BEGIN:VCALENDAR METHOD:PUBLISH PRODID:-//Q2S//Q2S Colloquium iCalendar file generator//NO VERSION:2.0 BEGIN:VTIMEZONE TZID:/Q2S/Europe/Oslo X-LIC-LOCATION:Europe/Oslo BEGIN:DAYLIGHT TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST DTSTART:19700329T020000 RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:+0200 TZOFFSETTO:+0100 TZNAME:CET DTSTART:19701025T030000 RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040604T131500 DTEND;TZID=/Q2S/Europe/Oslo:20040604T141500 SUMMARY:Q2S Colloquium: Online gaming: Audio and graphics aspects - Svensson, Holthe and Solvang DESCRIPTION:As a follow up of the Online gaming: An overview colloquium, this presentation goes more into the technical details of online gaming. Audio and graphics aspects are looked into. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200406041315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20030919T141500 DTEND;TZID=/Q2S/Europe/Oslo:20030919T151500 SUMMARY:Q2S Colloquium: Micro Measurements in High Capacity Networks - Hellan Jon Kåre DESCRIPTION:(Not available.) URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200309191415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20030912T141500 DTEND;TZID=/Q2S/Europe/Oslo:20030912T151500 SUMMARY:Q2S Colloquium: Quality Involves Security. Security in IP. - Svein Knapskog DESCRIPTION:(Not available.) URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200309121415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040130T141500 DTEND;TZID=/Q2S/Europe/Oslo:20040130T151500 SUMMARY:Q2S Colloquium: A Scaleable Monitoring Platform for the Internet - Arne Oslebo DESCRIPTION:SCAMPI is a two-and-a-half-year European project to develop a scalable monitoring platform for the Internet. As part of the project a new intelligent passive measurement card is being developed as well as a new monitoring API that makes it easier to develop new measurement applications. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E259 (Q2S Lunch area) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200401301415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040206T131500 DTEND;TZID=/Q2S/Europe/Oslo:20040206T141500 SUMMARY:Q2S Colloquium: Layered Coding and Congestion Addaptation in a Multicast Scalable Video Delivery System - Yuming Jiang DESCRIPTION:This talk introduces a color-resolution layered coding scheme and an automatic congestion adaptation scheme for a multicast video delivery system. In the system, a real-time video is encoded into a scalable bit stream using wavelet coding technique, which is further seperated into layers based on the colour and resolution information. These layers are then delivered over different multicast channels through the network to the video clients. Video clients contineouly probe the traffic condition in the network and subscribe to the appropriate number of video layers that can be supported by the network so as to achieve the best possible video quality. To futher enhance video quality at the clients, the video layers are prioritized and an automatic congestion adaptation scheme is implemented in the network such that packets in the base video layer have a low drop probability than those of the enhancement video layers. As a result, the video clients are able to receive a decodable video stream even when network congestion happens. The following are the two papers related to the talk: 1. Chen-Khong Tham, Yuming Jiang, and Yung-Sze Gan, “Layered Coding for a Scalable Video Delivery System”, IEEE/EURASIP Packet Video 2003 (PV 2003), 28-29 Apr 2003, Nantes, France. 2. Chen-Khong Tham, Yung-Sze Gan, and Yuming Jiang, “Congestion Adaptation and Layer Prioritization in a Multicast Scalable Video Delivery System”, IEEE/EURASIP Packet Video 2003 (PV 2003), 28-29 Apr 2003, Nantes, France. Their softcopies are available from: http://137.132.153.25/ymjiang/selectedpublications.html URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200402061315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040521T121500 DTEND;TZID=/Q2S/Europe/Oslo:20040521T131500 SUMMARY:Q2S Colloquium: Link-Based Fair Aggregation: A Simple Approach to Scalable Support of Per-Flow Service Guarantees - Yuming Jiang DESCRIPTION:To support service guarantees in packet-switched networks, three approaches have been proposed. They are the Stateless Core (SCORE) approach, the Integrated Services (IntServ) approach, and the Differentiated Services (DiffServ) approach. The granularities of service guarantees provided by these approaches at each router are respectively packet level, flow level, and class level. In this paper, we propose a novel approach, called Link-Based Fair Aggregation (LBFA) approach to scalable support of service guarantees. While the granularity of service guarantees supported by LBFA is link level at each router, we show through analysis that the proposed LBFA approach can achieve as good as or even better per-flow service guarantees than the current three approaches. Note: The paper was presented at IFIP Networking 2004 and has been published in Springer LNCS 3024, pp. 1084-1095, 2004. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:Q2S lunch area (E257) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200405211215@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20030905T141500 DTEND;TZID=/Q2S/Europe/Oslo:20030905T151500 SUMMARY:Q2S Colloquium: IP today and IP tomorrow. The European IPv6 research network. - Stig Venås DESCRIPTION:Unavailable URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200309051415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20031003T141500 DTEND;TZID=/Q2S/Europe/Oslo:20031003T151500 SUMMARY:Q2S Colloquium: IP and QoS - Øivind Kure DESCRIPTION:(Not available.) URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:Multimedia room, main building ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200310031415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20031017T141500 DTEND;TZID=/Q2S/Europe/Oslo:20031017T151500 SUMMARY:Q2S Colloquium: The Honeynet Project - Einar Oftedal DESCRIPTION:(Not available.) URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200310171415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20031107T141500 DTEND;TZID=/Q2S/Europe/Oslo:20031107T151500 SUMMARY:Q2S Colloquium: Processing of Scanned Images - Ajit Bopardikar DESCRIPTION:In this presentation some ideas on the processing of scanned images will be presented. First, methods for removing surface defects such as scratches, tears and dust from a flatbed-scanned image are discussed. These methods are based on a precise separation of the defects from the underlying image. This is critical to avoid any blurring or other alteration of the non-defective image data. Next, ideas for reduction and management of grain noise in scanned images are presented. This involves estimating and collecting statistics related to the grain in the image. These combined with specialized filtering operations are used to clean the image. Examples of both, defect detection and correction as well as grain reduction will be provided during the presentation. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200311071415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20031114T141500 DTEND;TZID=/Q2S/Europe/Oslo:20031114T151500 SUMMARY:Q2S Colloquium: Finding Resources in Networks using Ant-Like Agents - Otto J Wittner DESCRIPTION:The lecture will present work to be published in the proceedings of CEC\'03 (2003 Congress on Evolutionary Computation). URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200311141415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20030829T141500 DTEND;TZID=/Q2S/Europe/Oslo:20030829T151500 SUMMARY:Q2S Colloquium: Surround sound - Home cinema or more? - Peter Svensson DESCRIPTION:Unavailable URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200308291415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040625T131500 DTEND;TZID=/Q2S/Europe/Oslo:20040625T141500 SUMMARY:Q2S Colloquium: Efficient simulation of buffer overflow in queues with breakdowns - Victor Nicola DESCRIPTION:Efficient importance sampling methods are proposed for the estimation of overflow probabilities in a single server queue with server breakdowns. The server is assumed to alternate between the operational and failure states according to a CTMC. Both, continuous (fluid flow) and discrete (single arrivals) sources are considered. In the fluid flow model, we assume a Markov-modulated fluid source and a constant output rate when the server is operational. We show how known results on fluid queues may be applied to determine the optimal (exponentially tilted) change of measure. In the discrete arrivals model, we assume a Markov-modulated Poisson source and exponential service time when the server is operational. We show how known results on Markov additive processes may be applied to determine the optimal (exponentially tilted) change of measure. Empirical studies demonstrate the effectiveness of the proposed change of measures when used in importance sampling simulations. (Joint work with D.P. Kroese.) URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200406251315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040618T131500 DTEND;TZID=/Q2S/Europe/Oslo:20040618T141500 SUMMARY:Q2S Colloquium: Dynamic Routing After Service Disruption - Bjørn Jæger DESCRIPTION:This talk considers dynamic fault recovery routing in connection oriented packet switched networks using source node routing. The performance of communication networks immediately after a failure is dominated by a non-stationary traffic load that, in the worst case, can lead to network congestion with severe throughput degradation if not controlled. This talk focus on selecting an appropriate routing algorithm during dynamic fault recovery to control the network performance. A general optimization based formulation of the fault recovery problem is presented and used to model a variety of routing algorithms and fault scenarios. It is discussed how a distributed implementation relates to optimal routing and some results from a simulation based study are presented. Results show that routing algorithms optimal under steady state conditions are not optimal during failure conditions, and that a dedicated fault recovery routing scheme can improve network performance after failures. The results also show the importance of using representative metrics for measuring the network performance during fault recovery. Finally, some relating issues and some ideas for future work are presented. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200406181315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040611T131500 DTEND;TZID=/Q2S/Europe/Oslo:20040611T141500 SUMMARY:Q2S Colloquium: Online Gaming: Large scale online gaming - Gaute Godager DESCRIPTION:Funcom is a world leading developer and publisher of online entertainment, and has currently 19 game titles including well known titles such as The Longest Journey and Anarchy Online. Today Funcoms primarily focus is on online entertainment where Anarchy Online, a massive multiplayer game, is their flagship. This presentation introduces Funcom, and presents how online gaming at lagre scales can be achieved. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200406111315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040514T131500 DTEND;TZID=/Q2S/Europe/Oslo:20040514T141500 SUMMARY:Q2S Colloquium: Online Gaming: An Overview - Harald Øverby DESCRIPTION:Online gaming is a fast growing application area. There are several categories of such games. This presentation introduces online gaming in general, presents a set of game categories, dicusses marked, traffic and QoS issuse, and finally concludes by running a demo of an online first-person-shooter game (Quake 3) where the effects of introducing network impairments are demonstrated. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200405141315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040903T131500 DTEND;TZID=/Q2S/Europe/Oslo:20040903T141500 SUMMARY:Q2S Colloquium: Digital Cinema Unveiled - Andrew Perkis DESCRIPTION:“Digital Cinema is above all a concept, a complete system, covering the entire movie production chain from the acquisition with digital cameras to post-production to distribution to exhibition, all with bits and bytes instead of 35 mm film” URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200409031315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20040910T131500 DTEND;TZID=/Q2S/Europe/Oslo:20040910T141500 SUMMARY:Q2S Colloquium: Modeling Information Abuse Using Branching Processes - Tønnes Brekne DESCRIPTION:Branching processes are introduced as a stochastic tool for understanding the characteristics of the abuse of leaked information, and the associated risks. To understand the risk associated with information leakage, it is important to produce models capturing important aspects of the abuse of leaked information. This understanding is necessary to limit such risks effectively and efficiently. Filling part of an apparent gap in this area, a stochastic model based on a discrete-time branching process is introduced. Some general challenges associated with modelling information leak risks are identified, as well as some challenges associated with using branching processes to analyze operational risk. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200409101315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050401T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050401T151500 SUMMARY:Q2S Colloquium: Packet loss rate- and delay jitter differentiation in asynchronous optical packet switched networks - Harald Øverby DESCRIPTION:In this talk, we consider how access restriction may be utilized to provide packet loss rate- and delay jitter differentiation in an asynchronous optical packet switch with a contention resolution pool that contains both tunable wavelength converters and fiber delay lines. The proposed schemes enable an independent differentiation of packet loss rate and delay jitter by utilizing a combined access-restriction to output wavelengths, wavelength converters and fibre delay lines. The throughput penalty is quantified and evaluated for each scheme. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200504011415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050211T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050211T151500 SUMMARY:Q2S Colloquium: Removal of spatial irrelevancy in 3D audio utilizing Ambisonic and the continuity illusion. - Audun Solvang DESCRIPTION:Perceptual masking in temporal and frequency domain has up to recently been the basis for removal of irrelevancy in audio. This has been sufficient since audio in most cases has been reproduced in mono or stereo. The introduction of multichannel sound systems such as 5.1 (home theater) and 7. 1 (gaming) has opened for removal of irrelevancy in the spatial domain. This talk will present a way of removing spatial irrelevancy by exploiting the continuity illusion. The method is based on detection of possible strong sources ambisonics and spectral gating. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200502111415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050411T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050411T151500 SUMMARY:Q2S Colloquium: An Approach to Experimentally Obtain Service Dependability Characteristics of the Jgroup/ARM system - Hein Meling DESCRIPTION:Jgroup/ARM is a middleware framework for operating dependable distributed applications based on Java. Jgroup integrates the distributed object models of Java RMI and Jini with the object group communication paradigm, enabling the construction of groups of replicated server objects that provide dependable services to clients. ARM provides automated mechanisms for distributing replicas to host processors and recovering from replica failures. This paper describes an approach based on stratified sampling combined with fault injections for estimating the dependability attributes of a service deployed using the Jgroup/ARM middleware framework. A first experimental evaluation is performed focusing on a service provided by a triplicated server, and indicative predictions of various dependability attributes of the service are obtained. The evaluation shows that a very high availability and MTBF may be achieved for services based on Jgroup/ARM. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200504111415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050124T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050124T151500 SUMMARY:Q2S Colloquium: A parameter-based admission control for aggregate scheduling networks - Markus Fidler DESCRIPTION:Recent architectures for Quality of Service provide scalability by means of aggregating flows to few different traffic classes. Of particular interest among these is a Premium Service, which aims at ensuring defined end-to-end delay boundaries. Network Calculus is a theory of deterministic queuing systems that has already been applied successfully to solve similar problems in per-flow Integrated Services networks. However, in aggregate scheduling networks the derivation of tight delay bounds is significantly more complicated and still subject to research. The problem is caused by multiplexing and de-multiplexing effects that are hard to quantify. This talk will introduce basic concepts of Network Calculus and show how these extend to aggregate scheduling. An implementation of a parameter-based admission control will be introduced and related evaluation results will be presented. Finally, future directions towards a probabilistic Network Calculus and their benefits will be discussed. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200501241415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050429T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050429T151500 SUMMARY:Q2S Colloquium: Adaptation of Distributed Algorithms in Highly Dynamic Environments, Experimentation in Wireless Ad-hoc Networks. - Corine Marchand DESCRIPTION:Technological advances in wireless devices (laptop computers, personal digital assistants (PDAs), mobile phones, ...) bring up significance to new wireless technologies. Progress in wireless communication protocols (Bluetooth, WIFI, ...) allow the use of new ad-hoc networking schemes. Then, new challenges arise from the communication variability in wireless networks and the unpredictable disconnections of those heterogeneous devices, creating very dynamic topologies named ad-hoc wireless networks. In this context, to maintain the consistency of a wireless device group, we built a middleware addressing the distributed agreement problem in unreliable environment. Therefore, to characterize wireless environments performances, we first express a method, which tries to identify the factors acting upon system variability. Based on unreliable failure detectors, the consensus algorithm proposed is able to make a decision for distributed systems despite of unreliable communications or process failures (disconnections or crashes). An evaluation on either the behavior analysis and the quality of services has been performed to validate the method above. Keywords: Distributed algorithms, consensus and failure detectors, wireless ad-hoc networks, quality of service and modeling, performance evaluations. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200504291415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050601T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050601T151500 SUMMARY:Q2S Colloquium: Incorporating Attacker Behavior in Stochastic Models of Security - Karin Sallhammar DESCRIPTION:We describe a game-theoretic method to compute the probabilities of expected attacker behavior and we demonstrate how these probabilities can be incorporated in the transition rate matrix of a stochastic model for operational security assessment. The game theoretic method is based on a reward concept, which considers the effect of successful attacks as well as the possible cost of detection when computing the expected attacker behavior. Our method aims to fill an important gap in the application of reliability methodology to security evaluation. To demonstrate the usability of the method in different threat environments, an illustrative example is provied. Karin Sallhammar, Bjarne E. Helvik and Svein J. Knapskog, Incorporating Attacker Behavior in Stochastic Models of Security. To appear in proceedings of the 2005 International Conference on Security and Management (SAM\'05), Las Vegas, USA, June 20-23, 2005. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200506011415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050527T131500 DTEND;TZID=/Q2S/Europe/Oslo:20050527T141500 SUMMARY:Q2S Colloquium: Stochastic Network Calculus and its Impact - Yuming Jiang DESCRIPTION:Information theory for service guarantee analysis in stochastic networks has been identified as a grand challenge for future networking research. Stochastic network calculus is an important approach to it, which is a set of recent developments and results for stochastic service guarantee analysis. In this seminar, five basic properties required for a network calculus are first discussed. A stochastic traffic model and a stochastic server model are then introduced, with which a stochastic network calculus with the required basic properties has been developed. An example is given to demonstrate the use of stochastic network calculus in measurement-based admission control (MBAC). Finally, the impact of stochastic network calculus on analysis and cross-layer design of wireless networks is discussed. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200505271315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050526T093000 DTEND;TZID=/Q2S/Europe/Oslo:20050526T103000 SUMMARY:Q2S Colloquium: Quality of Experience for Personal Multimedia Communication Devices - Sun Kook Yoo DESCRIPTION:The presentation is part of the COST #276 workshop. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 2 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200505260930@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050810T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050810T151500 SUMMARY:Q2S Colloquium: Using quasigroups for PRNGs, Cryptographic Hash Functions, Stream Ciphers, One-way Functions, One-way Permutations, and Random Error Correcting Codes. - Danilo Gligoroski DESCRIPTION:I will present my recent research in Cryptology and Error Correcting Codes by the algebraic structures: Quasigroups. While every group is in the same time quasigroup, the oposite is not true. In general quasigroups are non- commutative, non-associative, non-idempotent, non- involutory and without neutral elements. That makes them very attractive mathematical objects for applications in Cryptology esspecially for building Pseudo Random Number Generators (PRNGs), for improving statistical characteristics of some known PRNGs, for defining Cryptographic Hash Functions, for fixing the vulnerabilities of some known and popular hash functions (like those from MD4 family), for defining One-way Functions, for defining One-way Permutations and for defining Random Error Correcting Codes. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:F3 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200508101415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050620T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050620T151500 SUMMARY:Q2S Colloquium: Honeypots - Christian Larsen DESCRIPTION:Based on my master thesis \"Using honeypots to document the threats from the blackhat-community\". More details will be added later. Master thesis description: The purpose of this master thesis is to collect and analyze security related data to learn more about malicious traffic on the Internet. The analysis should provide statistics for security-related traffic, as well as information about specific security incidents. To obtain these goals, the student will setup and maintain a low-interaction honeypot, in addition to measuring-equipment for this system. The system will further be extended to a distributed set of honeypots. A high-interaction honeypot may also be implemented to get a more detailed look at the methods of attack. The student will develop necessary guidelines for the system to ensure the quality of the collected data and the handling of the security of the system. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200506201415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050909T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050909T151500 SUMMARY:Q2S Colloquium: Research Proposals - Lech Janczewski DESCRIPTION:The objectives of the seminar are twofold: 1. To present the Auckland University (UofA) and teaching/research in the field of Information Systems conducted there 2. To present my current research interests and to discuss possible cooperation between Q2S and UofA Three research proposals will be presented and all of them will be in the field of information security. First proposal relates to the general issue of cyber terrorism. The second proposal deals with firewall configurations suitable for government departments and agencies. The third is investigation of protection of critical infrastructure against cyber attacks. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200509091415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050805T131500 DTEND;TZID=/Q2S/Europe/Oslo:20050805T141500 SUMMARY:Q2S Colloquium: Performance Evaluation of Multimedia Services over IP networks - Odd Inge Hillestad DESCRIPTION:We present a streaming media test bed for IP networks. Besides a streaming server and a streaming media client, it consists of a IP network emulator, a high-performance packet capture device and a packet flow regenerator enabling repeatable performance measurements of streaming media applications and network QoS mechanisms in a controlled environment. We also present some initial results from the work involved in verifying the performance of the packet regenerator. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200508051315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050819T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050819T151500 SUMMARY:Q2S Colloquium: The IETF vision of the Internet of the future - Harald Alvestrand DESCRIPTION:The Internet Engineering Task Force (IETF) has always eschewed prescribing specific architectures for the Internet, choosing rather to standardize components and let the net grow organically around these. Still, a few basic principles are part of the \"shared vision\" of IETF participants. This talk attempts to highlight some of these basic principles. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:F2 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200508191415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050824T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050824T151500 SUMMARY:Q2S Colloquium: Rate Control of Traffic Sources Based on Level Crossing in a Congested Buffer - Erling Austreim DESCRIPTION:Abstract: This paper presents a study of some rate control policies for traffic sources based on feedback from a congested buffer. The study of these policies is motivated by the increasing amount of traffic from applications using transport protocols without built-in mechanisms for congestion control. The sources are here modeled as simple ON-OFF sources, and the control policies have been studied based on a continuous fluid-flow approximation of the traffic. Further, we have looked at the level crossing rates in the queue to study how much signalling is required for these schemes when explicit congestion notification is given. Some measures on how this will affect the quality at the receiving end are also given. The presentation is to be held at ITC19 in Beijing, China. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:F2 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200508241415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050902T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050902T151500 SUMMARY:Q2S Colloquium: Random Waypoint Mobility Model and its Applications - Esa Hyytiä DESCRIPTION:The random waypoint model (RWP) is one of the most widely used mobility models in performance analysis of ad hoc networks. In RWP model each user, referred to as a node, moves independently of other users directly from its current waypoint to the next at a constant velocity. The waypoints are (typically) assumed to be independently and uniformly distributed in a given convex subset of plane. As a straightforward extension to the basic model one can include pause times at waypoints, use a non-uniform waypoint distribution and vary the velocity of the node according to certain rules. One interesting property of a mobility model is the resulting stationary distribution of nodes, i.e., the user density as a function of location. It may be also important to know how often a user visits a certain area, or, e.g., what is the user arrival rate into a given cell in a cellular network. In this presentation the corresponding results will be given for the RWP model and the results are illustrated through some examples of possible applications. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200509021415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20051104T141500 DTEND;TZID=/Q2S/Europe/Oslo:20051104T151500 SUMMARY:Q2S Colloquium: Source Specific Multicast (SSM) : Toward an extensible group communication service - Mickaël Hoerdt DESCRIPTION:Group communications using a multicast service over the Internet are both an old and active research topic due to its difficulty. The first contributions of the community have seen the definition of a general multicast group communication model offering more than a simple packet replication in the network: Any Source Multicast. Because of its generality and the exponential growth of the Internet after its definition, the multiple architectures which have attempted to implement it at the inter-domain level have rapidly been blocked by significant scalability and deployment problems. Holbrook solves these problems in an elegant way by the definition of a simpler model, which was still offering a packet replication service in the network: Source Specific Multicast. However, there are still several aspects that could prevent this model from being largely deployed in the Internet. Indeed, the connection of the different members of a multicast session needs to construct a multicast tree (to prevent loops) and this one is maintained by a set of stored states. The creation and the sharing of these states is not under the control of the network. We have experimentally checked the behavior of this repartition over generated graphs that respect Internet properties. We have defined several manners to enhance this repartition and we have developed a software (nec) which allowed us to map the Internet core. We have then extended our simulation work over the IPv6 internet topology in order to check our hypothesis on a network which is still in the early stage of development. Our results show that using the shortest multipaths is a working solution to decrease the number of multicast state on the most loaded routers in a dynamic and distributed way. These results show that realistic Internet maps are very important to evaluate our proposition. Indeed, significant differences appears when we use maps produced by nec or the maps generated by a graph generation tool which respects internet properties nem. Another aspect, which is a natural extension to the SSM model is the dynamic source discovery inside the same group session. Indeed, because of its simplification, the source discovery function is not included anymore in the model as it was the case for ASM. We have specified, implemented and evaluated a new architecture which allows to solve this problem. By defining controller, candidate controller, source and receiver entities and their interaction in a group communication, we define a robust and scalable session layer which allow a multipoint to multipoint communication and which only depends on the SSM network service. Evaluation results obtained by implementation confirms the starting hypothesis of our work: the SSM model is adapted to inter-domain for a large set of applications, including those which needs an efficient and dynamic source discovery support. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200511041415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050826T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050826T151500 SUMMARY:Q2S Colloquium: An introduction to the IPPM framework - Frank Aune DESCRIPTION:The IPPM framework is a set of standard metrics that can be applied to the quality, performance and reliability of Internet data delivery services. These metrics are designed such that they can be performed by network operators, end users, or independent testing groups. The overarching goal of the IPPM effort is to archive a situation in which users and providers of Internet transport service have an accurate common understanding of the performance and reliability of the Internet components \"clouds\" that they use and/or provide. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:UNINETT, meeting room "Rød", 5th floor ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200508261415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20050930T141500 DTEND;TZID=/Q2S/Europe/Oslo:20050930T151500 SUMMARY:Q2S Colloquium: An evolutionary approach to quality of service - Henrik Lundqvist DESCRIPTION:Providing a distinct service class for real-time applications over the Internet has been an active research area for a long time and several solutions have been proposed. However, the deployment has been very slow, since the benefits have not motivated the added technical and operational complexity. Therefore, we take a new approach, starting from a scheme based on probe-based admission control in the end-hosts, which works without any need for network support beyond best effort service. Once the end- hosts have been upgraded and conversational applications are more widely deployed on the Internet there is more incentive for operators to upgrade their networks. In this talk I will first present our host based service differentiation scheme and then show how different quality of service mechanisms in the network can interact with the probe-based admission control and allow different operators to choose their individual strategies for quality of service without need for common policies in the whole Internet. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200509301415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20051014T141500 DTEND;TZID=/Q2S/Europe/Oslo:20051014T151500 SUMMARY:Q2S Colloquium: Internet Failure Protection using Hamiltonian p-Cycles found by Ant-like Agents - Otto J Wittner DESCRIPTION:Swarm intelligence is a distributed system construction concept which has shown promising results when applied to problems within the area of network and operational management. Swarm Intelligence systems are fully distributed (without central components), have high redundancy, are adaptable, and can find near optimal solutions to NP-hard problems. This presentation describes a new swarm intelligence system based on the CE-ant algorithm developed by Helvik and Wittner. The system is capable of finding near optimal Hamiltonian protection cycles in meshed networks. These are suited for protection in small to medium sized networks (ASs). The presentation is to be held at DRCN 2005 i Naples, Italy. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200510141415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20051026T131500 DTEND;TZID=/Q2S/Europe/Oslo:20051026T141500 SUMMARY:Q2S Colloquium: Open issues in QoS provisioning - Chee-Kheong (David) Siew DESCRIPTION:The interest to provide quality of service (QoS) in the Internet has led to a plethora of research work that aims to provide QoS guarantee for many emerging applications in the Internet paradigm. As the Internet is based on the packet switching technology, the research work includes a wide range of topics, such as packet scheduling, admission control, flow and packet classifications, traffic policing, buffer management, etc. The accumulation and development of the research work in this area has led to two QoS architectures: Integrated Service (IntServ) and Differentiated Service (DiffServ). Integrated Service aims to provide per flow deterministic QoS guarantee but suffers from the issue of scalability. Differentiated service addresses this issue by means of flow aggregation and service is provided by means of a per-aggregate per-hop behavior. However, it provides coarse QoS and service differentiation among the traffic it services. This presentation provides a brief review of the major works that contribute to the proposal of these two architectures and discusses some of the remaining and interesting research issues in QoS provisioning. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200510261315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20051118T141500 DTEND;TZID=/Q2S/Europe/Oslo:20051118T151500 SUMMARY:Q2S Colloquium: Combining performance monitoring and location data in wireless networks - Laurent Paquereau DESCRIPTION:This paper focuses on investigation of methods for WLAN monitoring, and in particular how measurements and monitoring of wireless networks can benefit from user or terminal location data. By combining passive network monitoring data (trace based) with user or terminal location, quality measures such as coverage and quality maps can be generated. Compared to wired networks, management and monitoring of WLANs have additional challenges because the performance is heavily dependent on variable and unpredictable characteristics of the physical media (i.e. the air link). Consequently, there is an increasing need to understand how wireless technology will affect network management, troubleshooting and performance monitoring. This presentation is to be held at NIK\'05, Bergen, Norway. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200511181415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20051116T131500 DTEND;TZID=/Q2S/Europe/Oslo:20051116T141500 SUMMARY:Q2S Colloquium: Probabilistic Network Calculus: A System Theory for the Internet - Markus Fidler DESCRIPTION:A central aspect to networked applications is the performance of underlying communication systems. Relevant characteristics comprise capacity that has to be provisioned, buffer sizes that are required to achieve certain small loss rates, and end-to-end delays that need to be considered by real-time applications, such as telephony or video broadcasting. Queuing theory has been widely applied to analyze such performance measures and with the advent of network architectures for quality of service it has been complemented by network calculus which is a deterministic framework for worst-case analysis of backlogs and delays. Network calculus can be seen as a system theory under min-plus algebra and in almost the same manner as classical system theory it features intuitive and powerful convolution formulae for analysis of single servers as well as for concatenation of tandem servers. This concatenation property is of utmost importance since it establishes a general framework for efficient analysis of multiple node scenarios. Recent research loosens the worst-case assumptions of network calculus to evolve a probabilistic equivalent that benefits from statistical multiplexing of independent flows. Significant achievements have already been made, owing for example to the theory of effective bandwidths, however, the outstanding end-to-end scalability set up by deterministic network calculus has not been attained. To this end we establish a concise probabilistic network calculus which effectively builds on moment generating functions. The presented work features end-to-end probabilistic performance bounds that achieve the objective of scaling linearly in the number of traversed nodes. Unlike other known approaches the evolved calculus does not depend on additional a priori assumptions, such as busy period bounds. The consistent application of moment generating functions put forth in this work utilizes independence beyond the scope of current statistical multiplexing of flows. An important additional gain is demonstrated for different scheduling disciplines as well as for concatenation of network elements. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200511161315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20051202T141500 DTEND;TZID=/Q2S/Europe/Oslo:20051202T151500 SUMMARY:Q2S Colloquium: Trace driven simulation of rate adaptive MPEG-4 video - Arne Lie DESCRIPTION:Trace files of video and audio frame sizes have been used to investigate network behaviour and impact of audiovisual quality. The Evalvid streaming MPEG-4 video tool-set from Technical University of Berlin can e.g. be used both for real network and simulated network investigation. The media is reassembled and visual inspection and/or PSNR value generation is possible. However, there has been a lack of solutions for Rate Adaptive media content. This talk will present a solution that builds on modifications of the Evalvid tool set, and an adaptive rate controller that builds on SVBR (Hamdi/Roberts \'97). The benefits of the solution is the generation of real MPEG-4 streaming traffic, as well as a low-complexity rate controller that is a good compromise between optimal rate-distortion relaxation and complexity scalability when running many instances on the same computer. The modified tool-set is interfaced to ffmpeg and ns-2, and early results with video sequence visual inspections and PSNR calculations will be shown. References: valvid tool-set: http://www.tkn.tu- berlin.de/research/evalvid/ M. Hamdi, J. W. Roberts, P. Rolin, “Rate control for VBR video coders in broad-band networks”, IEEE Journal on Selected Areas in Communications, Vol. 15 no. 6, 1997. http://hpds.ee.ncku.edu.tw/~smallko/ns2/Evalvid_in_NS2.htm URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200512021415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060127T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060127T151500 SUMMARY:Q2S Colloquium: On periods of Edon-(2m,2k) Family of Stream Ciphers - Danilo Gligoroski DESCRIPTION:This is the presentation for the paper (by the authors Gligoroski, Markovski and Knapskog) that was accepted for SASC 2006 - Stream Ciphers Revisited, Special Workshop hosted by the ECRYPT Network of Excellence Leuven, Belgium, February 2-3, 2006. Edon80 is a candidate for a stream cipher due to the call of ECRYPT in 2005 - eSTREAM. Edon80 takes an approach that is radically different from other candidates, it uses a very long pipeline to transform a periodic input stream into a more complex key stream. It appears that Edon80 is the only cipher submitted to eSTREAM for which a strong mathematical analysis of the period exists. I will present how LogNormal distribution is obtained for the distribution of keystream period of Edon80. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200601271415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060210T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060210T151500 SUMMARY:Q2S Colloquium: Quantile estimation in large data sets and streaming data. - Valeriy Naumov DESCRIPTION:Abstract: For 0 < q < 1, the p-quantile (percentiles) of a distribution is the value at or below which 100q percent of the distribution lies. Extreme quantile estimation strategy depends of the properties of the distribution tails. Quantile estimation strategies for packet delay and for IP flow duration are different simply because packet delay distribution is bounded while IP flow durations are heavy tailed. Fortunately, there exist only three main classes of distribution tails, which simplifyes strategy selection. First part of the presentation gives an introduction to the extreme value theory and its application to quantile estimation. The second part deals with new approaches to quantile estimation in large data sets and streaming data. References: 1) R. Jain and I. Chlamtac. The P2 algorithm for dynamic calculation of quantiles and histograms without storing observations, Communications of the ACM, vol. 28, no. 10, 1985, pp. 1076–1085. 2) J. Diebolt, M.-A. El-Aroui, V. Durbec and B. Villain. Estimation of Extreme Quantiles: Empirical Tools for Methods Assessment and Comparison, Int. Journal of Reliability, Quality and Safety Engineering, vol. 7, no. 1, 2000, pp.75–94 3) V. Naumov and O. Martikainen. Exponentially Weighted Simultaneous Estimation of Several Quantiles, Proc. Int. Conference on Data Analysis (ICDA-2005), Budapest, October 26-28, 2005, pp. 71-75. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200602101415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060908T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060908T151500 SUMMARY:Q2S Colloquium: Self-tuned Refresh Rate in a Swarm Intelligence Path Management System - Otto J Wittner DESCRIPTION:This is a test of a presentation to be held at IWSOS 2006 in october. The paper abstract is given below. CE-ants (Cross Entropy ants) is a distributed, robust and adaptive swarm intelligence system for dealing with path management in communication networks. This paper focuses on strategies for adjusting the overhead generated by the CE-ants as the state of the network changes. The overhead is in terms of number of management packets (ants) generated, and the adjustments are done by controlling the generation rate of ants traversing the network. The self-tuned strategies proposed in this paper detect state changes implicitly by monitoring parameters and ant rates in the management system. Rate adaptation is done both in the network nodes and in the peering points of the virtual paths. The results are promising, and compared to fixed rate strategies the self-tuned strategies show a significant saving (70-85%) in number of packets, and has similar (even slightly better) data packet delay and service availability. The rate adaptation in network nodes provides fast restoration with short path detection times and hence also high service availability. The implicit self-tuned ant rate in the path endpoints improves the convergence time on link state events without flooding the network with management packets in steady state when these are not required. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200609081415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060609T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060609T151500 SUMMARY:Q2S Colloquium: HETEROGENEOUS FINITE-SOURCE RETRIAL QUEUES - János Sztrik DESCRIPTION:In this talk we investigate a single server retrial queue with a finite number of heterogeneous sources of calls. It is assumed when a given source is idle it will generate a primary call after an exponentially distributed time. If the server is free at the time of the request\\\'s arrival then the call starts to be served. The service time is also exponentially distributed. During the service time the source cannot generate a new primary call. After service the source moves into free state and can generate a new call again. If the server is busy at the time of the arrival of a primary call, then the source starts generating so called repeated calls with exponentially distributed times until it finds the server free. As before, after service the source becomes free and can generate a new primary call again. We assume that the primary calls, repeated attempts and service times are mutually independent. This queueing system and its variants could be used to model magnetic disk memory systems, local area networks with CSMA/CD protocols and collision avoidance local area networks. The novelty of this model is the heterogeneity of the calls, which means that each call is characterized by its own arrival, repeated and service rates. The aim of the investigation is to give the usual steady-state performance measures of the system. To do so, an efficient software tool, MOSEL ( Modeling, Specification and Evaluation Language ) developed at the University of Erlangen, Germany, is used to formulate and solve the problem. Several sample numerical results illustrate the power of the tool showing the effect of different parameters on the system measures. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200606091415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060324T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060324T151500 SUMMARY:Q2S Colloquium: Dependability Modelling and Analysis of Networks as Taking Routing and Traffic into Account - Qitao Gan DESCRIPTION:The existing work on dependability modelling and analysis of networks have main focuses on the, structural properties. However, the communication networks also have dynamic characteristics and behavioral properties, such as changes of topology, routes, and traffic loads, which should necessarily be reflected in the modelling. We regard the dependability modelling and analysis of IP networks with an intra-domain routing and traffic handling. This yields to an increased complexity in the modelling and analysis, due to the increase of the state space. Several techniques have been proposed to deal with the growth of the state space. To an analyst, an interesting point is, whether he/she can make a trade-off to the factors under consideration, i.e. the model representativeness vs. modelling complexity, and computation efforts vs. result accuracy. To meet these requirements, we propose a modelling approach where failures and repairs of network components as well as routing and traffic handling are described by a set of stochastic activity networks (SAN). The SANs are designed to restrict the generation of the state space to the most probable states, which enables an analysis without creation of an excessively large state space and achieving a sufficient accuracy of the result. A case study based on the Norwegian university IP backbone network demonstrates the applicability of this approach. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200603241415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060331T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060331T151500 SUMMARY:Q2S Colloquium: 1) A model for TCP congestion control capturing the correlations in times between the congestion events, 2) On Load Balancing in a Dense Wireless Multihop Network - Esa Hyytiä DESCRIPTION:1) We consider a simplified model for the rate control of TCP sources. In particular, we assume idealised negative feedbacks upon reaching a certain total sending rate, i.e., at the moment when the total sending rate attains a given capacity limit C one of the TCP sources is given a negative feedback and the source reduces its sending rate in a multiplicative manner. Thus, the model takes into account the interactions between different flows appropriately in the microscopic level instead of assuming independence. For this model we are able to derive steady state equations and solve them. Furthermore, we are able to compute several important performance measures such as the mean and the variance of the total sending rate. Moreover, we are able to characterise the packet loss process at the bottleneck link and, in particular, the correlations therein. 2) We study the load balancing problem in a dense multihop network, where a typical path consists of large number of hops, i.e., the spatial scales of a typical distance between source and destination, and mean distance between the neighbouring nodes are strongly sepatated. In this limit, we present a general framework for analysing the traffic load resulting from a given set of paths and traffic demands. We formulate the load balancing problem as a minmax problem and give two lower bounds for the achievable minimal maximum traffic load. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200603311415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060302T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060302T151500 SUMMARY:Q2S Colloquium: Quantile Estimation.Part 2 – Streaming Data. - Valeriy Naumov DESCRIPTION:First we consider new methods for estimation of the mean and the tail index. Then we discuss drawback of classical methods for quantile estimation and propose a solution. Finaly we combine all parts together and present a method for simultaneous estimation of several quantiles in stationary and non-stationary streaming data. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200603021415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060321T131500 DTEND;TZID=/Q2S/Europe/Oslo:20060321T141500 SUMMARY:Q2S Colloquium: Trådløse Trondheim som forsknings-lab - Steinar Andresen DESCRIPTION:Presentasjonen vil fokusere på i hovedsak tekniske (men også enkelte administrative) aspekter ved prosjektet \"Trådløse Trondheim\" som er relevante for potensiell forskningsvirksomhet i nettet. Følgende temaer vil bli belyst: - QoS mekanismer - Målepunkter - SLA - Sikkerhet - Monitorering - Handover mellom operatører/teknologier URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:B212, "Savannen" ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200603211315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060428T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060428T151500 SUMMARY:Q2S Colloquium: Delay analysis of IEEE 802.11e EDCA and 802.11 DCF - Olav Østerbø DESCRIPTION:The majority of analytical work on the performance of IEEE 802.11 focuses on predicting the throughput and the mean delay of only the medium access, although higher layer applications and protocols are interested in the total performance of the MAC layer. Seen in this perspective, surprisingly little focus has been on predicting the queueing delay. The main contribution of this work opposed to others is that it presents the full delay distribution through the z-transform. As a result, the mean medium access delay is found by the first order moment of the transform, and the mean queueing delay by the second order moment. Together this gives the average total delay associated with the MAC layer. In addition to finding the moments of the delay, the z-transform is inverted numerically using the trapezodial rule and with a configurable error bound (- in this paper restricted to 10- 14). This gives the full delay distributions both of the MAC delay, the queueing delay and the total delay. All desirable delay percentiles follow. The z-transform is derived from an analytical model that works in the whole range from a lightly loaded, non-saturated channel to a heavily congested, saturated medium. The model describes the priority schemes of the Enhanced Distributed Channel Access (EDCA) mechanism of the IEEE 802.11e standard. EDCA provides class-based differentiated Quality of Service (QoS) to IEEE 802.11 WLANs, and distinguishes between four different traffic classes – called Access Categories (AC). By setting the number of ACs to one, and by using an appropriate parameter setting, the results presented are also applicable to the legacy 802.11 Distributed Coordination Function (DCF). References (internal access only). URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200604281415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060905T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060905T151500 SUMMARY:Q2S Colloquium: A Game-theoretic Approach to Stochastic Security and Dependability Evaluation - Karin Sallhammar DESCRIPTION:The complex networked computer systems of today are often vulnerable to a large number of failures, accidental as well as intentional. To be able to assess to what degree one can rely on such a system, new methods for quantitative evaluation is needed. This paper presents a stochastic model for integrated security and dependability evaluation, which models malicious attacker behavior as transitions between system states. To predict the probabilities of attack actions a game theoretic approach is applied. We demonstrate the method by computing security and dependability measures in two different case studies. This paper will appear at the 2nd IEEE International Symposium on Dependable, Autonomic and Secure Computing (DASC\'06), Indianapolis, USA, Sep 29 - Oct 1, 2006. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200609051415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060512T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060512T151500 SUMMARY:Q2S Colloquium: Open Telephony - Olav Kvittem DESCRIPTION:The telephony service is seeing a disruptive transition to be internet-based. This talk will present SIP-based telephony and the way UNINETT foresee a way forward for the academic sector. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200605121415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060615T131500 DTEND;TZID=/Q2S/Europe/Oslo:20060615T141500 SUMMARY:Q2S Colloquium: 3DTV : Scene Extraction and Representation Issues - A. Aydin Alatan DESCRIPTION:3DTV is expected to be the next target for consumer electronics. This ambitious goal still requires many complex problems to be solved, such as, extraction of 3-D information of the recorded scene from visual data; representation of this 3-D scene information in the most efficient and the least distorted way; compression and transmission of the represented 3-D information; and finally, display of the transmitted 3-D content, which should yield 3-D perception to a viewer. This talk focuses on 3-D extraction and representation problems within 3DTV. Although, it is possible to utilize multiple cameras for 3-D scene reeconstruction, there is also significant demand to achieve the same goal with a single camera due to the vast existence of such recording equipment, as well as many available mono-view content. Fortunately, any relative motion between the camera and the scene/objects, yields enough clues to extract 3-D information. Self-calibration of the cameras, segmentation of indepedendently moving objects from background ,as well as each other, prioritization of frame pairs for better reconstruction and dense estimation of disparity information at all points of the scene are the sub-problems with some novel solutions. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200606151315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060904T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060904T151500 SUMMARY:Q2S Colloquium: Grid InterNetworking and QoS for the Grid - Michael Welzl DESCRIPTION:The importance of Grid Computing is constantly growing. While the term was very broadly defined as \\\"coordinated resource sharing and problem solving in virtual teams\\\" by Ian Foster, a Grid usually consists of computationally demanding applications that should be accelerated via appropriate parallelization. The underlying infrastructure is the Internet. Grid applications have special requirements regarding network usage, and they show some unusual properties from the network perspective. It is therefore obvious and reasonable to optimize Internet technology for such usage. After a brief overview of Grid networking, this talk will introduce one particular Grid specific network enhancement, namely a QoS architecture that is currently being developed at the University of Innsbruck. In Grids, there is significant demand for QoS, but typically for file transfers instead of multimedia data transfers (as in the common case). The sketched architecture uses congestion control as the core element for building fine-grain QoS, which enables it to make more efficient use of resources because file transfers are elastic. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200609041415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060907T140000 DTEND;TZID=/Q2S/Europe/Oslo:20060907T150000 SUMMARY:Q2S Colloquium: Internet Transport Tomorrow - introducing SCTP, UDP-Lite and DCCP - Michael Welzl DESCRIPTION:With the standard socket interface that is deployed in most common operating systems, the Internet currently provides two different transport services: 1. unreliable datagram delivery (based on the User Datagram Protocol, UDP) 2. reliable in-order delivery of a consecutive data stream (based on the Transmission Control Protocol, TCP) Within a few years, however, an Internet application programmer can be expected to face the following choice of transport services (provided by her operating system) due to recent IETF developments: *simple unreliable datagram delivery - with or without delivery of erroneous data *unreliable congestion controlled datagram delivery - with a choice of congestion control mechanisms - with or without delivery of erroneous data *reliable congestion controlled in-order delivery of - a consecutive data stream - multiple data streams *reliable congestion controlled unordered but potentially faster delivery of logically independent data chunks This talk introduces the new IETF protocols that will provide these services: SCTP, UDP-Lite and DCCP. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 3 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200609071400@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20060915T141500 DTEND;TZID=/Q2S/Europe/Oslo:20060915T151500 SUMMARY:Q2S Colloquium: Using Hidden Markov Models to Evaluate the Risks of Intrusions - André Årnes DESCRIPTION:Security-oriented risk assessment tools are used to determine the impact of certain events on the security status of a network. Most existing approaches are generally limited to manual risk evaluations that are not suitable for real-time use. In this paper, we introduce an approach to network risk assessment that is novel in a number of ways. First of all, the risk level of a network is determined as the composition of the risks of individual hosts, providing a more precise, fine-grained model. Second, we use Hidden Markov models to represent the likelihood of transitions between security states. Third, we tightly integrate our risk assessment tool with an existing framework for distributed, large-scale intrusion detection, and we apply the results of the risk assessment to prioritize the alerts produced by the intrusion detection sensors. We also evaluate our approach on both simulated and real-world data. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200609151415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20061006T141500 DTEND;TZID=/Q2S/Europe/Oslo:20061006T151500 SUMMARY:Q2S Colloquium: Application of the RESTART/Splitting Technique in Object-Oriented Simulation + A Module-Based Wireless Node for NS-2 - Anders Mykkeltveit DESCRIPTION:Two test-presentations will be given in this colloquium. Both are presentations to be held at workshops, RESIM 2006 and WNS2. ---- A Module-Based Wireless Node for NS-2 Over the last decade an extraordinary amount of research work at all layers of the network stack has focused on wireless and mobile networks, e.g. wireless local area networks (WLAN), in parallel with their wide acceptance as access technologies. Simulation has been used massively to develop, test and compare new ideas and protocols tailored for such networks and ns-2 has been the most used network simulator for these studies. However, the support for wireless and mobile networking in ns-2 is monolithic and not entirely consistent with basic design principles so that it becomes now a burden for making the simulator evolve. It makes it tedious, if not impossible, to support new features such as multiple wireless interfaces. To overcome the current limitations, the MobileNode object itself is questioned and a new, more flexible and better integrated layout of existing components to support wireless and mobile networking using modules (MW-Node) is presented. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200610061415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20061103T141500 DTEND;TZID=/Q2S/Europe/Oslo:20061103T151500 SUMMARY:Q2S Colloquium: An experimental analysis of VoIP over WLAN (preceded by an overview of the Performance Engineering Lab, Dublin) - Seán Murphy DESCRIPTION:This talk will first give an overview of the activities of the Performance Engineering Lab in Dublin with a strong emphasis on the mobile/wireless and multimedia activities that take place in the group. Then, the talk will discuss some specific work that we have been doing in the context of resource management for VoIP over WLAN. In particular, the talk will discuss some experimental work on terminal based admission control and link adaptation mechanisms. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200611031415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20061117T141500 DTEND;TZID=/Q2S/Europe/Oslo:20061117T151500 SUMMARY:Q2S Colloquium: (1) A Hybrid Modelling Approach for Analyzing Service Availability; (2) Refined Classification of Service Unavailability for Comparison - Qitao Gan DESCRIPTION:(1) In this paper, we present a modelling method for quantitative evaluation of availability attributes for end-to-end transport services protected by shared backup paths in IP networks. A hybrid modelling approach with simulation and model analysis is pursued to avoid an excessive computational effort. (2) In this paper, we propose a classification of service unavailability refined by different contributors. These contributors are orthogonalized so that they can be identified separately and used as common metrics for fair evaluation. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200611171415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20061124T141500 DTEND;TZID=/Q2S/Europe/Oslo:20061124T151500 SUMMARY:Q2S Colloquium: Multisensor Real-time Risk Assessment using Continuous-time Hidden Markov Models - Kjetil Haslum DESCRIPTION:The use of tools for monitoring the security state of assets in a network is an essential part of network management. Traditional risk assessment methodologies provide a framework for manually determining the risks of assets, and intrusion detection systems can provide alerts regarding security incidents, but these approaches do not provide a real-time high level overview of the risk level of assets. In this paper we further extend a previously proposed real-time risk assessment method to facilitate more flexible modeling with support for a wide range of sensors. Specifically, the paper develops a method for handling continuous-time sensor data and for determining a weighted aggregate of multisensor input. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200611241415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070112T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070112T151500 SUMMARY:Q2S Colloquium: Network Security and the Evolution of Intrusion Detection Systems: A Computational Intelligence Perpective - Ajith Abraham DESCRIPTION:Recently cyber security has emerged as an established discipline for computer systems and infrastructures with a focus on protection of valuable information stored on those systems from adversaries who want to obtain, corrupt, damage, destroy or prohibit access to it. Several information security techniques are available today to protect information systems against unauthorized use, duplication, alteration, destruction and virus attacks. An Intrusion Detection System (IDS) is a program that analyzes what happens or has happened during an execution and tries to find indications that the computer has been misused. In this talk, we present some of the challenges in designing efficient intrusion detection systems which could provide high accuracy, low false alarm rate and reduced number of features. Finally, we present how some of the computational intelligence paradigms could be used in designing intrusion detection systems (programs) in a distributed environment. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200701121415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070209T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070209T151500 SUMMARY:Q2S Colloquium: Image Processing for Forensic Science Applications - Sergio Carrato DESCRIPTION:In the forensice science field, image processing applications have some specific requirements and contraints, mainly related to the traceability of the operations, and the often very poor quality of the input image/video. The first issue is easily dealt with following a suitable documentation process; for the second one, suitable algorithms have to be developed/considered. In the talk, a brief review will be done on the image processing tasks normally needed in forensic science, and some details will be given on a few algorithms, developed at the University of Trieste, which have been applied to some of these tasks. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200702091415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070216T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070216T151500 SUMMARY:Q2S Colloquium: Optimal Packet Scheduling and Rate Control for Video Streaming - Eren Gurses DESCRIPTION: In this paper, we propose a new low-complexity retransmission based optimal video streaming and rate adaptation algorithm. The proposed OSRC (Optimal packet Scheduling and Rate Control) algorithm provides average reward optimal solution to the joint scheduling and rate control problem. The efficacy of the OSRC algorithm is demonstrated against optimal FEC based schemes and results are verified over TFRC (TCP Friendly Rate Control) transport with ns-2 simulations. Authors: Eren Gurses, Gozde Bozdagi Akar and Nail Akar URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200702161415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070305T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070305T151500 SUMMARY:Q2S Colloquium: Characterization of Slice-based H.264/AVC Encoded Video Traffic - Astrid Undheim DESCRIPTION:An explicit slice-based mode type selection scheme for use in H.264/AVC has recently been developed, which preserves the coding efficiency of H.264/AVC without requiring any modifications to the standard. The novel scheme avoids the burstiness effect of standard frame-based H.264/AVC by breaking up the Group Of Pictures (GOP) structure and each frame contains an intracoded slice at successive positions. A large intracoded frame is then only present at the beginning of each sequence. In addition, the first frame in each scene is large because of the prediction error when trying to predict the current frame based on the last frame in the previous scene. In this work a single slice-based encoded video stream is studied. The characteristics of the video stream divided into scenes using a scene change detection algorithm are investigated, looking at the marginal distributions and the correlations. A simulation study, looking at the multiplexing properties and the buffer overflow probabilities for a slice-based encoded stream compared to a frame-based encoded stream is also performed. The study shows that frame correlation is present only at small lags, and the periodic correlation structure seen in frame-based encoded video is mostly removed for the stream under study. Results from simulations show that the slice- based encoded video stream performs better than the frame- based encoded video stream in terms of lower packet loss rates and lower packet delay as long as the buffer size is small or the link utilization is moderate. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200703051415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070316T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070316T151500 SUMMARY:Q2S Colloquium: Confidentiality of Traffic Data - A Quality of Protection View - Dogan Kesdogan DESCRIPTION:One of the most important values in the information society is the information itself. Therefore, the protection of this precious good is a crucial task. A lot of research attention has been devoted to protecting the information contained within messages. This can be achieved easily today by using encryption techniques. In this talk we focus not on the protection of such content data but rather on how to ensure the confidentiality of traffic data, i.e. information about communication relations. Protection of traffic data usually results in some form of anonymity. Such confidentiality is important, since third parties’ unrestricted access to traffic data is considered an unacceptable invasion of both private and business lives. Several techniques are known to protect traffic data. However, there is still a lack of models to evaluate the level of protection these techniques can provide. The need for models that give designers enough insight into the protection task are of top priority. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200703161415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070420T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070420T151500 SUMMARY:Q2S Colloquium: Optimization techniques and applications - Crina Grosan DESCRIPTION:Abstract: Optimization problems are encountered daily in each of our lives. While most of us may fail to recognize the structure of these problems, they exist at many levels of complexity. Such optimization problems can vary from relatively simple, single input variable, single objective (SO) problems to multivariate, multiobjective optimization problems (MOPs) of great complexity. While obtaining the optimal solution to an MOP and hence solving it is the ultimate goal of any attempt to optimize an MOP, the desire of most researchers is to find an acceptable solution to MOPs. This talk reviews some of the contributions in the field of optimization from standard mathematical approaches to latest developed algorithms pointing on the application suitability of each of these techniques. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200704201415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070427T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070427T151500 SUMMARY:Q2S Colloquium: COMMUNICATION ACOUSTICS - Jens Blauert DESCRIPTION:Those aspects of acoustics which concern the relations of acoustics to the information and communication technologies are now frequently called \"Communication Acoustics\". After a short review of the history of this field, relevant results from recent research at the Institute of Communication Acoustics at the Ruhr-University of Bochum, Germany, will be reported. This work can be seen in the light of the research areas of Computational Auditory Scene Analysis (CASA) and Auditory Virtual Environments (AVE) - both dealing with the parametric representation of auditory scenes. Recent application opportunities and future trends will be discussed. It will be argued that modern communication-acoustical systems - which are often only embedded components in more complex communication systems - require more and more built-in explicit knowledge. Among other things, the development of such components and systems calls for data and knowledge from the cognitive sciences. Today’s programs for education in communication engineering and communication acoustics do often not yet take sufficient account of this trend. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200704271415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070504T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070504T151500 SUMMARY:Q2S Colloquium: Quality Aware Application Service Configuration in a Stochastic Grid Environment - Sharath Babu Musunoori DESCRIPTION:Achieving acceptable application performance in a distributed environment remains a difficult challenge. In particular, this is true for applications composed of services that need certain quality requirements to be fulfilled. The key problem considered here is the partitioning / configuration of application services (service graph) in a stochastic distributed environment (network graph). This talk introduces a new branch of decentralized multi- agent based algorithms for solving the service partitioning problem. Despite the dynamic nature of a distributed environment, the proposed algorithms are able to find a feasible solutions for a given service composition. In this respect, co-operative agents used in decision making process follow the basic principles of nature-inspired approaches such as learning automata, ant system and their combination. The proposed methods demonstrate that nature inspired approaches are more capable of working with distributed decisions in random environments. Further, test results indicate that the learning/coordination is an essential component for achieving scalability and efficiency in nature-inspired systems. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200705041415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070518T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070518T151500 SUMMARY:Q2S Colloquium: Performance Modeling of an Apache Web Server with a Dynamic Pool of Service Processes - Udo R. Krieger DESCRIPTION:In the current Internet the performance of service delivery crucially depends on the proper and efficient operation of Web servers. It is determined by their software architecture and characterized by the applied processing model. Here we consider the Unix software architecture of an Apache Web server with its non-threaded multi-processing module Prefork. For the first time we propose a tractable multi-server model to approximate the performance of the load-dependent dynamic behavior of Apache\'s resource pool of available HTTP service processes. Furthermore, we show that this Markovian queuing model can be solved by advanced matrix-geometric methods. Then the efficiently computed performance results of this analytic model are compared with measurements of a real Apache Web server. The outcome clearly indicates that our analytic model can very accurately predict the mean-value performance of Apache under the Prefork policy. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200705181415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070530T090000 DTEND;TZID=/Q2S/Europe/Oslo:20070530T100000 SUMMARY:Q2S Colloquium: An Architecture for Self-healing Autonomous Object Groups - Hein Meling DESCRIPTION:Jgroup/ARM is a middleware for developing and operating dependable distributed Java applications. Jgroup integrates the distributed object model of Java RMI with the object group paradigm, enabling construction of replicated servers that offer dependable services to clients. ARM aims to improve the dependability characteristics of systems through fault treatment, focusing on operational aspects where the gain in terms of improved dependability is likely to be the greatest. ARM offers two core mechanisms: recovery from node, object and network failures and distribution of replicas. ARM identifies failures and reconfigures the system according to its dependability requirements. This paper proposes an enhancement of the ARM framework in which replica placement is performed in a distributed manner, eliminating the need for a centralized manager with global information about all object groups. Instead each autonomous object group handles their own replica placement based on information from nodes. Assuming that multiple objects groups are deployed in the system, this constitutes a distributed replica placement scheme. This scheme enables the implementation of self-healing object groups that can perform fault treatment on themselves. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 4 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200705300900@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070529T110000 DTEND;TZID=/Q2S/Europe/Oslo:20070529T120000 SUMMARY:Q2S Colloquium: Estimation of Losses by Exceedances of Encoded Video Traffic - Natalia Markovich DESCRIPTION:The losses of video traffic due to the exceedances of capacity channel level are considered. The video traffic data with a specific encoding system are analyzed. The conclusions regarding heaviness of tail and dependence structure are made. The mean and overall losses are calculated using the so called extremal index and the mean excess function. The extremal index shows the mean number of exceedances over a threshold (capacity of channel) per block of data. The obtained characteristics are discussed. The talk is provided by plots and tables. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:Savannen ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200705291100@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070613T101500 DTEND;TZID=/Q2S/Europe/Oslo:20070613T111500 SUMMARY:Q2S Colloquium: Computational Forensics: Methodological foundations for forensic analysis of signatures - Katrin Franke DESCRIPTION:In recent years, mathematical, statistical and computer science methods have found extensive applications in developing new procedures for crime investigation, prosecution and the enforcement of law. At the same time, computer-based methods have become important assistance tools for police officers and forensic experts in specialized fields. Yet, in other domains the examinations still heavily depend on the knowledge and intuition of a human expert. This talk gives a brief overview of potentials of computational methods in forensic sciences. The state of the art is described, some practical examples are referred to and a further view is indicated hoping that the application of these methods will soon be extended to those fields, in which we still rely on expert knowledge only. One of the fields known to rely on expert knowledge only is the analysis of questioned documents and handwriting. Despite great efforts to provide adequate expert training, the methodology of forensic handwriting analysis has frequently been criticized, in particular for the lack of studies on validity and reliability. Although, a certain amount of promising research has been done, computer-based handwriting analysis is rarely applied in daily forensic casework. The examination of handwritten signatures is not supported by automated or computer-aided procedures at all. Therefore, it is appropriate to examine whether forensic signature analysis can profit from recent developments in technology. This talk presents new computational methods for discovering and evaluating ink-trace characteristics related to the human writing process. These characteristics are considered to provide clues on the authenticity of a questioned specimen. Our technological research is conducted under consideration of perspectives and findings from a number of other fields, namely forensics, human-movement science, computer vision and computational intelligence as well as robotics. The research method is \"Analysis by Synthesis\". Recorded pen movements are used to program a writing robot in order to ensure the production of ink traces on paper under strictly controlled conditions. The behavioral characteristics of the signing process and the characteristics of the synthesized ink trace are systematically studied, drawing conclusions for forensic analysis and computational method designs. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200706131015@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070824T131500 DTEND;TZID=/Q2S/Europe/Oslo:20070824T141500 SUMMARY:Q2S Colloquium: DIPS: A Framework for Distributed Attack Prediction and Intrusion Prevention Using Hidden Markov Models and Online Fuzzy Risk Assessment - Kjetil Haslum DESCRIPTION:This paper extends the functioning of a Distributed Intrusion Detection System (DIDS), which consists of several IDS over a large network (s), all of which communicate with each other, or with a central server that facilitates advanced network monitoring. A Hidden Markov Model is proposed for sensing intrusions in a distributed environment and to make a one step ahead prediction against possible serious intrusions. Distributed Intrusion Prevention System (DIPS) is activated based on the predicted threat level and risk assessment of the protected assets. Intrusions attempts are blocked based on (1) rate of packet flow (2) prediction of possible serious intrusions (3) a serious attack that has already occurred and (4) online risk assessment of the assets possibly available to the intruder. This paper focuses on the distributed monitoring of intrusion attempts and one step ahead prediction of such attempts and online risk assessment using fuzzy inference systems. Preliminary experiment results indicate that the proposed framework is efficient for real time distributed intrusion monitoring and prevention. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 1 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200708241315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20070921T141500 DTEND;TZID=/Q2S/Europe/Oslo:20070921T151500 SUMMARY:Q2S Colloquium: New results for speech recorded from distributed microphones - Ian Burnett DESCRIPTION:In this presentation I will provide an overview and introduction to current research at Whisper Labs, School of Electrical, Computer and Telecommunications Engineering at the University of Wollongong, NSW, Australia. The research extends from XML related multimedia delivery schemes through to spatial audio and speech signal processing. Following the brief summary, I will consider some of our recent results in the area of speech signal processing and in particular the areas of speech localisation in reverberant room environments and the LP Spectral distortions associated with delays induced by distributed microphone arrays. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:EL 2 ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200709211415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20071005T141500 DTEND;TZID=/Q2S/Europe/Oslo:20071005T151500 SUMMARY:Q2S Colloquium: Fast Hello; A means to speed up the convergence of the OSPF - Michael (Huaiyuan) Ma DESCRIPTION:Currently, the time for OSPF routers to reach the \"ExStart\" state depends on the OSPF HelloInterval. To reach the \"ExStart\" state as soon as possible, one of approach is to shorten HelloInterval. This speech will discuss another method that can be applied to significantly reduce the time to reach the \"ExStart\" state. With this method, a router will immediately reply a Hello Packet to its peer when receiving a neighbor\'s Hello Packet. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:Q2S lunch room (E-257) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200710051415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20071023T141500 DTEND;TZID=/Q2S/Europe/Oslo:20071023T151500 SUMMARY:Q2S Colloquium: Securing communication in a dynamic network environment - Saqib Ali DESCRIPTION:In dynamic network environments, unlike traditional wireless networks, nodes do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. A main challenge in the design of these networks is their vulnerability to security attacks. In this research we study the threats faced to the dynamic network environment and the security goals to be achieved. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200710231415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20071105T141500 DTEND;TZID=/Q2S/Europe/Oslo:20071105T151500 SUMMARY:Q2S Colloquium: Activities at the Multimedia Technology Group in Prague - Milos Klima DESCRIPTION:The presentation will be devoted to the overview of activities of the Multimedia Technology Group at the Department of Radioelectronics, Faculty of Electrical Engineering, Czech Technical University in Prague. The group members are active in the field of multimedia (audiovisual) technology with special attention to the qualitative aspects of both audio and video information – source compression, transducers, objective and subjective quality evaluation and the modeling of visual and auditory system. Selected results of our research work will be presented. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200711051415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20071116T141500 DTEND;TZID=/Q2S/Europe/Oslo:20071116T151500 SUMMARY:Q2S Colloquium: Statistical and Deterministic QoS guarantee in OBS/OPS edge nodes - Guoqiang Hu DESCRIPTION:In Optical Burst Switched (OBS) and Optical Packet Switched (OPS)networks, traffic assemblers are deployed in the edge nodes to aggregate the client traffic into optical data frames of large sizes. Thus, the requirement on the processing speed of the electronic Switch Control Units (SCU) in the core switching nodes can be significantly relieved, so as to assure the implementation feasibility or reduce the realization cost. However, the introduction of the assembly procedure brings additional assembly delay and has also an impact on the characteristics of the network traffic, which should be closely inspected in the End-to-End (E2E) Quality of Service (QoS) provisioning. In this presentation, I give an overview of my research activities and achievements in the design of QoS frameworks in OPS/OBS networks, with a focus on the issues in edge nodes. After a short introduction of the OBS/OPS network architecture, the QoS requirements in an edge node are summarized. The delay performance in the edge node is especially evaluated by the statistical queueing analysis and deterministic analysis, from which the QoS measures of delay jitter or maximal delay can be derived. Based on the performance analysis, the E2E QoS frameworks are established for the statistical guarantee and deterministic guarantee, respectively. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200711161415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20071120T110000 DTEND;TZID=/Q2S/Europe/Oslo:20071120T120000 SUMMARY:Q2S Colloquium: \"Biomedical image processing : Applications to Echocardiography\" and \"Improvement of digital image watermarking techniques based on FPGA\" - Mohamed E. El Hadedy DESCRIPTION:In this presentation, Mr. El Hadedy will present some of his current and previous work. The first part of the presentation is concerned with biomedical image processing in general and applications to echocardiography in particular. This work was done under supervision Prof. Fatma EL Zahraa in the Mansora University. The second part of the presentation deals with digital watermarking techniques implemented in FPGAs, a body of work that was done under supervision of Professors Mohy El-din Ahmed Aboelsaud (Mansora University) and Mahmoud Ali Ashour (Egyptian Atomic Energy Authority). URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200711201100@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20071126T141500 DTEND;TZID=/Q2S/Europe/Oslo:20071126T151500 SUMMARY:Q2S Colloquium: Multimedia communication and sensor networks in an industrial environment - Anna Kim DESCRIPTION:In this presentation, I will first give a summary of my activities and results at ABB strategic R&D for Oil and Gas, within the Project TAIL/IO during the past 8 months. This is followed by an overview of the topic \"multimedia communication and sensor networks in an industrial environment\". The talk will try to provide answers to the following questions: what is an industrial environment? Why do we need multimedia and sensor networks in the industry? and What are the challenges and possible solutions? Examples and case studies that are specific to the oil and gas industry will be presented. In particular, I\'ll discuss the concept of \'intelligent environment\' and \'control room of the future\'. Current results on distributed wireless networks will be presented in more detail, along with plans for future research activities. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200711261415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20071128T130000 DTEND;TZID=/Q2S/Europe/Oslo:20071128T140000 SUMMARY:Q2S Colloquium: Integration of Smart Caching and Overlay Networks for Wireless Communication Networks - Ali Abbas DESCRIPTION:In this presentation, I will discuss how I have developed an Overlay Layer with Smart Caching capability to handle network heterogeneity, which in turn increases network performance. Overlay layer\'s architecture, integration and performance evaluation with the help of user scenarios are also going to be discussed. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200711281300@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20071204T141500 DTEND;TZID=/Q2S/Europe/Oslo:20071204T151500 SUMMARY:Q2S Colloquium: Ubiquitous Platform Mixed-Reality Contents Service - Sun Kook Yoo DESCRIPTION:[TBA] URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200712041415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080222T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080222T151500 SUMMARY:Q2S Colloquium: A Survey of Resilience Differentiation Frameworks in Communication Networks - Anders Mykkeltveit DESCRIPTION:The seminar is based on a paper recently published in IEEE Surveys & Tutorials. It is authored by Piotr Cholda (AGH), Anders Mykkeltveit (Q2S), Bjarne E. Helvik (Q2S), Otto J. Wittner (Q2S) and Andrzej Jajszczyk (AGH). This research is an outcome of a co-operation between AGH University of Science and Technology, Kraków, Poland and Q2S, NTNU within the European IST Network of Excellence (NoE) EuroFGI. The paper has been nominated for the \"Fred W. Ellersick Prize Award\". Abstract: The current trend is to integrate a constantly increasing number of services in the same communication network. Some services have very high resilience requirements, while other services have lower ones. This scenario calls for frameworks capable of provisioning for multiple services in a cost-efficient manner, and already a large number of frameworks has been proposed in the literature. This article presents a comprehensive survey of research efforts related to resilience differentiation in the Internet and telecommunications networks. We present a general framework classification which is used as the basis for the subsequent review of the relevant literature. Finally, a critical evaluation of the state-of-the-art and future challenges facing operators and designers is given. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200802221415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080229T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080229T151500 SUMMARY:Q2S Colloquium: Evaluation of Perceived Quality in Interactive Audiovisual Application Systems based on MPEG-4 - Ulrich Reiter DESCRIPTION:The object-based scene concept of the international standard ISO/IEC 14496 (MPEG-4) lends itself very well for the description of interactive audiovisual content. This concept has facilitated the evolution of classical audiovisual media like television into modern interactive audiovisual applications. Content created for these applications is not tied to specific reproduction devices or setups anymore, thus enabling a true convergence of the media.

Because of limited available computing power at the reproduction side it is desirable to decrease the computational load imposed by these applications as much as possible without degrading the perceived overall quality. Unlike for the unimodal presentation of audio or video programme material, bimodally (in the audiovisual domain) perceived quality is not easily predictable. Above all this is because the two modalities mutually influence each other. Unfortunately, the mechanisms underlying the human bimodal perception are not well understood. Aspects of user interaction with the application add to the complexity of the problem.

In order to name the factors that determine the perceived overall quality of interactive audiovisual applications it is necessary to perform subjective assessments. This is usually done evaluating the perceived overall quality while varying certain quality attributes and determining what impact these variations have. In this presentation, an MPEG-4 based system developed for performing such audiovisual assessments in a largely automated way is described. By applying the system, first evidence regarding audiovisual interdependency and influence of interaction upon human perception could be collected.

URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200802291415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080306T111500 DTEND;TZID=/Q2S/Europe/Oslo:20080306T121500 SUMMARY:Q2S Colloquium: Hierarchical Bayesian Based Trust and Reputation Management Framework - Mozhgan Tavakolifard DESCRIPTION:The rapidly changing environment of the internet suffer from problem of fragile trustworthiness of millions active entities such as humans and mobile agents on the internet. This problem is nontrivial, as more and more commercial transactions get carried out over the internet. Therefore, devising an effective approach for verification of trustworthiness in such complex environments is essential. However, the trust mechanism plays a key role in security of multi-agent systems. Also the trust establishment is nontrivial, since the traditional and social means of trust cannot be applied directly to virtual settings of these environments. Because, in many cases the involved parties did not have any interaction before. Therefore, the reputation techniques must be used instead to stimulate the good qualities and behaviors in online markets and communities, and also sanction the poor qualities and bad behaviors. To this end, the Ntropi framework was designed to facilitate the exchange of trust and reputation in information and/or business environments. This work presents an automated and autonomous trust system using Bayesian inference along with improved Dirichlet distribution. Our main contributions are the application of maximum likelihood method in the trust/reputation model to estimate the parameters used in Dirichlet distribution, and also the introduction of a hierarchical Bayesian method in the proposed reputation management model. In addition, a retrusting mechanism (forgiveness) is incorporated into the Ntropi framework to improve the whole performance of the proposed model. The simulation results indicate the effectiveness of proposed model. Since the quality of a reputation system depends on the integrity of the ratings it receives as input, so a fundamental problem would be that a rater may rate an agent more positively or more negatively than the real experience. To resolve these problems, we used a statistical filtering technique for excluding unfair ratings, which proved to be very effective through different simulations. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200803061115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080310T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080310T151500 SUMMARY:Q2S Colloquium: Dimension Reduction and Expansion: Distributed Source Coding in a Noisy Environment - Anna Kim DESCRIPTION:We studied the problem of distributed coding and transmission of inter-correlated sources with memory. Different from the conventional distributed source coding structure which relies on design of effective channel codes to model the inter-correlation and quantizer, the proposed system utilizes distributed compressed sensing [DCS06] for signal dimension reduction through linear matrix operations and dimension expansion for protection against channel noise through a hybrid scalar quantizer linear coder [Coward00]. The proposed system is optimized for minimum end-to-end distortion under a transmission energy constraint. Its performance is verified through simulation and can serve as a good starting point for designing similar analogue based dimension reduction-expansion schemes for applications in sensor networks. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200803101415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080314T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080314T151500 SUMMARY:Q2S Colloquium: QoS Architecture in Ad Hoc Networks: Effects of Shadow Classes and ECN to Regulate the Load - Tor Kjetil Moseng DESCRIPTION:We propose and analyze an augmented DiffServ architecture for ad hoc networks. A scheme based on shadow classes and ECN is used to control the load. By including ECN we are able to regulate the admitted flows and the best- effort traffic in order to avoid congestion and improve the conditions for the prioritized traffic. Through simulations we analyze the proposed architecture, and illustrate trade-offs between utilization of the network resources and the QoS performance. By tuning the regulation mechanisms we can adapt to different network environments and performance targets. The presentation is based on a paper to be presented at IEEE WCNC in Las Vegas, USA, March 31. - April 3., 2008. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 [Q2S LUNCH ROOM] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200803141415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080402T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080402T151500 SUMMARY:Q2S Colloquium: A Network Calculus Interpretation of Available Bandwidth Estimation - Markus Fidler DESCRIPTION:Available bandwidth denotes the share of the capacity of a network path that is unused by cross-traffic. The idea to estimate theavailable bandwidth from measurements dates back to packet pair probing and TCP congestion control. It plays an important role for the Internet, with applications e.g. in monitoring, dimensioning, traffic engineering, admission control, and quality of service. In spite of a variety of probing schemes, the fundamentals of bandwidth estimation are still not precisely understood. In our work, we explore the task of bandwidth estimation in the framework of min-plus systems theory and the network calculus. Interestingly, the solutions to the resulting inversion problem substantiate various known methods for bandwidth estimation. This fundamental connection between network calculus and bandwidth estimation provides essential insights and lays a foundation for new and improved estimation methods. This talk presents joint work with Jorg Liebeherr and Shahrokh Valaee (University of Toronto). URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 [Q2S lunch room] ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200804021415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080408T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080408T151500 SUMMARY:Q2S Colloquium: On the importance of the key separation principle for different modes of operation - Danilo Gligoroski DESCRIPTION:The key separation principle for different modes of operation of the block ciphers is a cryptographic folklore wisdom that states: One should always use distinct keys for distinct algorithms and distinct modes of operation. If this principle is violated, then there are generic attacks that can recover the whole or a part of the encrypted messages. By the advent of software packages and libraries that offer some or all modes of operation of block ciphers, the violation of this principle is really possible in practice. We show that under the same key, OFB mode of operation is a special case of the CBC mode ofoperation, and that if CBC and CTR modes of operation are interchangeably used under the same secret key - then the security of the encryption process is seriously weakened. Moreover in the chosen plaintext attack scenario with interchanged use of CBC and OFB mode under the same key, we give a concrete list of openssl commands that can extract the complete plaintext without knowing the secret key, also when the recommendations in the NIST SpecialPublication 800-38A 2001, "Recommendation for Block Cipher Modes of Operation" are meticulously followed. The paper is co-authord by Suzana Andova, and is to be presented at The 4th Information Security Practice and Experience Conference (ISPEC 2008) 21-23 April 2008, Sydney, Australia. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200804081415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080414T090000 DTEND;TZID=/Q2S/Europe/Oslo:20080414T100000 SUMMARY:Q2S Colloquium: Multilateral Security - Dogan Kesdogan DESCRIPTION:The use of various types of data processing equipment (including notebooks, cell phones, Personal Digital Assistants etc.) has become commonplace. All these systems are linked through the Internet and through telecommunication networks. We use these communication networks everywhere and every time. Although security of the technology is a prerequisite for trustworthy usage of computer systems many applications offer neither privacy nor secure identification. Depending on the participants of a service (e.g. users, service providers, network operators) the security requirements of each party may differ and even conflict. As a result, an essential element in the design of communication systems is to balance the security requirements of all parties in an acceptable way. Multilateral Security offers a solution by allowing users to individually define and enforce their security requirements. In this talk we present the concept of Multilateral Security and discuss the ways of implementing it. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-257 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200804140900@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080605T101500 DTEND;TZID=/Q2S/Europe/Oslo:20080605T111500 SUMMARY:Q2S Colloquium: Transducers with the direct D/A conversion. - Ahmed Shawky Moussa DESCRIPTION:Transducers with the direct D/A conversion. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200806051015@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080606T101500 DTEND;TZID=/Q2S/Europe/Oslo:20080606T111500 SUMMARY:Q2S Colloquium: Psychometry and evaluation of sound codecs - Ahmed Shawky Moussa DESCRIPTION:Psychometry and evaluation of sound codecs URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200806061015@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080611T130000 DTEND;TZID=/Q2S/Europe/Oslo:20080611T140000 SUMMARY:Q2S Colloquium: Towards Mobile Music Edutainment: A Multimedia Approach - Wang Ye DESCRIPTION:With the hope to foster research collaborations between our universities, I would like to give first a brief introduction to School of Computing, National University of Singapore. This will be followed by an overview of research activities in my group - Towards Mobile Music Edutainment: A Multimedia Approach. Modern mobile systems from mobile phones to laptops are becoming increasingly more powerful in terms of computation, memory and connectivity. Such devices typically have a very high degree of integration of multimedia components (microphone, speaker, camera, accelerometer, etc.) and functionalities (MP3 player, video caption and playback, game, etc.). We seek to leverage on such capabilities of mobile devices to facilitate music education and entertainment. I will give an overview of two research projects: 1) multimedia-based music content analysis for computer-assisted musical instrument tutoring; 2) perception-aware low-power media processing for mobile devices. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200806111300@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080612T111500 DTEND;TZID=/Q2S/Europe/Oslo:20080612T121500 SUMMARY:Q2S Colloquium: The Design of Intelligent Adaptive Network State Updating Mechanism for the Optimization of QoS Network Performance under Uncertainty - Ahmed Shawky Moussa DESCRIPTION:Large-scale communication networks are complex dynamical fuzzy systems. To architect these networks as intelligent systems, intelligence must be incorporated into their individual communicating components. The sought intelligence can be applied to the modeling and design, the maintenance of state information, and the routing protocols. In a large-scale dynamical network, the global network state information is inherently imprecise. The nature and the level of the inevitable imprecision vary significantly when different information updating policies are applied, which directly affects the routing decisions and the network performance. Though, the trend in QoS Networking research has been to focus on developing routing algorithms, while regarding the updating policies as supplements to the routing algorithms in order to enable their implementation. In this paper, we reverse the tradition by setting the primary goal to be the design of an intelligent and adaptive network state updating policy. The proposed mechanism, regardless of the routing algorithm, aims at the optimization of the network performance, by dynamically maintaining the optimal trade-off between the degree of imprecision and the overhead associated with the updates. The proposed mechanism is based on the use of fuzzy overlapping tolerance classes and is designed to implement bounded uncertainty and controlled overhead without the need for hold-down timers. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200806121115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080613T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080613T151500 SUMMARY:Q2S Colloquium: Quantification of Anonymity for Mobile Ad Hoc Networks - Marie Elisabeth Gaup Moe DESCRIPTION:Privacy has become an increasing concern for users of communication services. As communication networks are becoming more complex and diverse, the trustworthiness of network nodes, like routers, cannot always be guaranteed. In order to properly define secure anonymous routing it is useful to have a security model that represents the system, and to have some sort of measure that can quantify the amount of anonymity offered by the protocol. We present a probabilistic system model for anonymous ad hoc routing protocols that takes into account the a priori knowledge of the adversary and illustrate how the information theoretical entropy measure can be used for quantification of the anonymity of the system as the adversary captures an increasing number of nodes in the network. The proposed measurement schema is applied to ANODR and ARM routing protocols. The presentation is based on a paper accepted at STM 2008, the 4th International Workshop on Security and Trust Management, that is to be held in conjunction with IFIP TM 2008, June 16-17th in Trondheim. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200806131415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080703T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080703T151500 SUMMARY:Q2S Colloquium: Group Signature - Peiqing Zhang DESCRIPTION:A group signature scheme allows members of a group to sign messages on behalf of group without revealing the identity of the signer. Signature can be verified with respect to a single group public key. What is more, there exists a designated group manager, which can trace the identity of the signer (i.e. reveal the identity of the signer) when a dispute happens. This presentation is based on Peiqings Master\'s Thesis, in which she pointed out that two existing group signature schemes are vulnerable to the coalition attack and structured an ID-based Group Signature. She will introduce some background knowledge and related problems as well. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200807031415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080715T090000 DTEND;TZID=/Q2S/Europe/Oslo:20080715T100000 SUMMARY:Q2S Colloquium: Available Bandwidth Measurements in 802.11 Wireless LANs - Michael Bredel DESCRIPTION:In recent years wireless local area networks based on the IEEE 802.11 standard have been widely deployed. Nevertheless, the estimation of QoS-parameters, like available bandwidth that is the residual capacity left over by some unknown cross traffic, is still challenging. To address this topic we present results from an extensive measurement study of bandwidth estimation in wireless LANs. We show that, best to our knowledge, none of the well known probing methods reports the available bandwidth but in the best case an estimate of a fair bandwidth share. Our measurement results confirm this view and we conclude that under the current probe gap and probe rate models the fair share can only be loosely related to the available bandwidth. This talk presents joint work with Markus Fidler. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200807150900@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080822T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080822T151500 SUMMARY:Q2S Colloquium: Quantifying the strategy taken by a pair of ensemble hand-clappers under the influence of delay. - Nima Darabi DESCRIPTION:Pairs of subjects were placed in two acoustically isolated rooms clapping together under an influence of delay up to 68 ms. Their trials were recorded and analyzed based on a definition of compensation factor or CF. This parameter was calculated from the recorded observations for both performers as a discrete function of time and thought of as a measure of the strategy taken by the subjects while clapping. Increasing the delay CF was shown to be increased linearly as it is desired to avoid tempo decrease for such high latencies. Theoretically a critical value for CF was defined as tempo over measure (or beat) duration and was used to explain why very short latencies may lead to a tempo acceleration in accordance with Chafe effect. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200808221415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080910T110000 DTEND;TZID=/Q2S/Europe/Oslo:20080910T120000 SUMMARY:Q2S Colloquium: Effective Security of Software Installations. - Pern Hui Chia DESCRIPTION:Security measures are often ineffective due to lax enforcement and poor usability. On the mobile platforms, software certification alone does not guarantee correct behaviors of software. When installing unauthenticated applications, users are only prompted with warning messages that they have been conditioned to click-through. Online reviews are not integrated into the installation process to deter users from installing badware. Global software voting systems are also susceptible to online manipulation. Our work improves the effective security of software installation through social collaboration and security usability. We present a decentralized social rating system which is characterized with positive features including higher rating integrity, self-correcting, visible/traceable individual ratings, and effective distribution of security information. We incorporate social rating into an improved UI and installation flow taking into accounts behavioral, social sciences, besides technical security. Concepts in usable security like simplicity, early signaling, safe defaults, security by design, and visibility are employed. We also devise a set of mechanisms to distribute software ratings locally or through the rendezvous server in a secure manner. Our design is implemented as a prototype system on the Nokia Internet Tablet (N810). URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200809101100@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080912T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080912T151500 SUMMARY:Q2S Colloquium: Performance of Transport Protocols in IEEE 802.16 Networks - Kai Wang DESCRIPTION:The Worldwide Interoperability for Microwave Access (WiMAX) is an IEEE 802.16 standard that defines the air interface for fixed broadband wireless access (BWA). WiMAX is designed to support heterogeneous services and applications with different QoS requirements and traffic characterizations. However, resource allocation for TCP- based services is limited because they are usually grouped into the best effort (BE) service class. BE is the least privileged service class and has no QoS guarantees at all. Therefore, bandwidth allocation is not ideally suitable for TCP. In this work, we first study the recent works in the literature. Next, the performance of TCP in WíMAX networks is investigated using simulations. We find that TCP performance is highly dependent on WiMAX settings such as frame duration, modulation and coding schemes, direction of flows, and downlink to uplink (DL: UL) ratios. Most of these choices impact performance by exacerbating the MAC- layer asymmetry inherent in the technology. In such asymmetric networks, we note that throughput and goodput performance not only depends on the amount and kind of traffic in the downlink, but also on the bandwidth slots allocated for acknowledgments in the reverse channel as well. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200809121415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080924T110000 DTEND;TZID=/Q2S/Europe/Oslo:20080924T120000 SUMMARY:Q2S Colloquium: Modeling of Nonlinear Active Circuits Using FDTD Approach - Nima Darabi DESCRIPTION:This paper was presented at the 12th WSEAS International Conference on COMMUNICATIONS on Crete Island the 23-25 of July 2008. The paper, describes a voltage- source formulation of the extended finite-difference time-domain algorithm for the purpose of modeling nonlinear microwave devices. Based on this approach, the device-wave interaction is characterized and incorporated into FDTD algorithm. Analysis of nonlinear properties, including harmonic generation and intermodulation, can be accomplished by using a large signal device circuit model. This technique is applied to the analysis of a typical nonlinear microwave amplifier, which includes a three-terminal active MESFET device. Simulation results are in good agreement with MICROWAVE OFFICE results. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200809241100@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20080926T141500 DTEND;TZID=/Q2S/Europe/Oslo:20080926T151500 SUMMARY:Q2S Colloquium: Learning Trust in Dynamic Multiagent Environments using HMMs. - Marie Elisabeth Gaup Moe DESCRIPTION:In open multiagent systems agents are owned by a variety of stakeholders and can enter and leave the system at any time. Therefore trust is a fundamental concern in effective interactions, which is a key component of such systems. In this paper, we propose a trust model for autonomous agents in mulitagent environments based on hidden Markov models and reinforcement learning. By this combination the reliability of the hidden Markov model will be improved since its parameters are re-estimated after training of the model with the reinforcement learning module. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200809261415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20081010T141500 DTEND;TZID=/Q2S/Europe/Oslo:20081010T151500 SUMMARY:Q2S Colloquium: An Information-Driven Approach to Wireless Sensor Networking - Kui Wu DESCRIPTION:Quality of Service (QoS) is an essential requirement for most applications over distributed networks. Traditional solutions to the problem are mainly network-oriented, i.e., they focus on QoS routing, resource provisioning, admission control, reliable transmission, and so on. We argue that this may be a dead end for quality guarantee for wireless sensor networks. This talk introduces our recent research on QoS support with a purely information-driven approach, particularly, information-driven scheduling and data streaming. (A paper was recently presented at ACM MobiHoc 2008.) For effective sensor scheduling, we develop a generic framework to address several important technical challenges, including how to partition the sensors into clusters, how to dynamically maintain the clusters in response to environmental changes, how to schedule the sensors in a cluster, how to explore spatial and temporal correlation, and how to restore the data in the sink with high fidelity. For quality guaranteed data streaming, we develop online algorithms with linear time complexity and constant cost in space. The low cost nature of our methods leads to the unique advantages of their applications in massive and fast streaming environment, low bandwidth networks, and heavily constrained nodes in computational power. We implement and evaluate our methods over a real test bed with MICA2 sensors. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200810101415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20081022T111500 DTEND;TZID=/Q2S/Europe/Oslo:20081022T121500 SUMMARY:Q2S Colloquium: Trust Transferability Among Similar Contexts - Mozhgan Tavakolifard DESCRIPTION:Trust is a fundamental concern in electronic transactions and behavior of people are influenced by the situation. Motivated by that we present a state-of-the-art survey of context representation in trust management and provide main directions along which research efforts have been done. We propose a generalized model which considers different aspects of the relationship between context-awareness and trust management. This paper will be presented at the 4th ACM International Symposium on QoS and Security for Wireless and Mobile Networks (Vancouver, October 27-31) URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200810221115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20081024T141500 DTEND;TZID=/Q2S/Europe/Oslo:20081024T151500 SUMMARY:Q2S Colloquium: TSR: Trust-based Secure MANET Routing using HMMs - Marie Elisabeth Gaup Moe DESCRIPTION:In this paper we propose a trust-based security extension to the mobile ad hoc network dynamic source routing protocol (DSR), where the state probability of a node, according to its corresponding hidden Markov model (HMM), is being used for deciding the node\'s trustworthiness. Our approach detects the selective packet dropping behavior of selfish nodes that could not be detected or defended against with previous suggested solutions. Packet-dropping nodes that are acting selfishly by selectively dropping packets and not sharing their bandwidth with the rest of the network, are excluded from the network. Thus enforcing cooperation among nodes and removing the incentives for selfish node behavior. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200810241415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20081028T141500 DTEND;TZID=/Q2S/Europe/Oslo:20081028T151500 SUMMARY:Q2S Colloquium: General aspect of Multimedia Quality Assessment and my main activities in that area. - Vittorio Baroncini DESCRIPTION:General aspect of Multimedia Quality Assessment and my main activities in that area. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200810281415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20081029T111500 DTEND;TZID=/Q2S/Europe/Oslo:20081029T121500 SUMMARY:Q2S Colloquium: Traffic engineering with Multiprotocol Label Switching - Bushra Qayyum DESCRIPTION:The growing internet traffic and swelling demand for better and reliable services has put the Internet Service Providers (ISPs) around the world in struggle to keep up with the advancements. The probe of the day is how to make the most effective use of the available bandwidth in a large Internet Protocol (IP) backbone network for best output of the existing IP networks as well as obtain performance even in the event of congestion. The goal of Traffic Engineering is efficiency in resource allocation and utilization, and performance. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200810291115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20081114T141500 DTEND;TZID=/Q2S/Europe/Oslo:20081114T151500 SUMMARY:Q2S Colloquium: Survivability in Networks - Poul Heegaard DESCRIPTION:In a telecommunication network it is essential to provide virtual connections between peering nodes with certain performance guarantees such as minimum throughput, maximum delay or loss. Critical services in telecommunication network should be continuously provided even when undesirable events like sabotage, natural disasters, or network failures happen. The design, construction and management of network infrastructures and service platforms aim at meeting such requirement. In this paper we consider the network's ability to survive major and minor failures in network infrastructure and service platforms that are caused by undesired events that might be external or internal. Survive means that the services provided comply with the requirement also in presence of failures. The emph{network survivability} is quantified as defined by the ANSI T1A1.2 committee which is the transient performance from the instant an undesirable event occurs until steady state with an acceptable performance level is attained. In this research we assess the survivability of a network with virtual connections exposed to link or node failures. The survivability is quantified in terms of packet delay distributions for each virtual connection. The analytic approach is validated against simulations of a real network topology and the results show very good correspondence comparing simulations with the analytic approach. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200811141415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20081128T141500 DTEND;TZID=/Q2S/Europe/Oslo:20081128T151500 SUMMARY:Q2S Colloquium: Cross-Situation Trust Reasoning - Mozhgan Tavakolifard DESCRIPTION:We propose an ontology-based approach for inferences linking trust information in two different situations. That reasoning process can augment the typically sparse trust information, by inferring the missing information from other situational conditions, and can better support situation-aware trust management. Our work is more comprehensive in comparison with other models and considers various aspects of the relationship between situation-awareness and trust management. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200811281415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20081217T101500 DTEND;TZID=/Q2S/Europe/Oslo:20081217T111500 SUMMARY:Q2S Colloquium: Quality of Experience (QoE) Guidelines for real-time communication services expressed in Quality of Service (QoS) terms - Bjørn Hestnes & Peter Brooks . DESCRIPTION:What technical level of QoS is required to achieve a certain level of QoE for videoconferencing users in particular communication situations? What about other real-time communication services, such as multimedia communication and mobile TV? An ETSI Specialist Task Force (STF 354 ) is developing an ETSI Guide and a web-based guideline and tutorial system to help network operators, service providers and system manufacturers develop user-centred real-time communication services. An overview of the work will be presented and the web-based system demonstrated. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200812171015@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090128T111500 DTEND;TZID=/Q2S/Europe/Oslo:20090128T121500 SUMMARY:Q2S Colloquium: The Acoustic Centre; a New concept for a Loudspeaker - John Vanderkooy DESCRIPTION:Please note that in addition to the following presentation Rozenn Nichol of France Telecom will have a presentation at 1500 with the title "Binaural technologies: why and how to individualize binaural rendering?" This paper focuses on uses for the acoustic centre concept, which in this paper represents a particular point for a loudspeaker that acts as the origin of its low-frequency radiation or reception. Although there are near-field effects very close to the loudspeaker, the acoustic centre has a clear meaning even a short distance from the enclosure, up to frequencies of about 300 Hz for typical systems. The concept, although new to loudspeakers, has long been employed for microphones when accurate acoustic pressure calibration is required. The study is underpinned by: (1) a mathematical multipole expansion of the output of a loudspeaker, (2) an acoustic boundary-element calculation of a number of loudspeaker systems, and (3) some measurements that corroborate the concept of the acoustic centre. The concept is applied to subwoofers, for which the acoustic centre is essentially a cabinet dimension away from the centre of the cabinet. This has an influence on its radiation pattern in a normal room with reflecting walls. Another application that we consider is the effective acoustic position of the ears on the head at lower frequencies. This shows that the acoustic centres of the ears are well away from the head, and the effective ear separation is larger than expected. This has implications for the human localization mechanism. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200901281115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090130T141500 DTEND;TZID=/Q2S/Europe/Oslo:20090130T151500 SUMMARY:Q2S Colloquium: Adaptive and Online Anomaly Detection in Computer Networks: Current work and Perspectives - Wei Wang DESCRIPTION:Anomaly Detection is an important issue in current defense-in-depth security framework. Many existing anomaly detection methods require a large amount of precisely labeled data to build a static model that is then used for detection. In practical environments, however, labeled data is very difficult to obtain. Moreover, the audit data for attack detection is typically streaming and the behavioral model is always evolving. Static detection models thus lead to considerable false positives. In this presentation, we propose a novel general framework for adaptive and online anomaly detection in computer networks. The general framework can be based on any online clustering methods. A detection model based on the framework is able to learn online and deal with concept drift in audit data streams. StrAP are used to validate the framework. The detection model based on the framework automatically labels the web audit data and adapts to normal behavior changes while identifies attacks through dynamical clustering of the streaming data. A very large size of real HTTP Log data collected in our institute is used to validate the framework and the model. The preliminary testing results demonstrated its effectiveness and efficiency. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200901301415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090206T141500 DTEND;TZID=/Q2S/Europe/Oslo:20090206T151500 SUMMARY:Q2S Colloquium: QoS in Heterogeneous Networks - Fazal Wahab Karam DESCRIPTION:The architecture of the future wireless networks seems to be more open and may include heterogeneous access networks. The access networks could be connected to different IP-backbone networks and relate to different providers.This multi-radio access situation opens the potential to offer access to any network utilizing a number of access techniques at the same time, not necessarily belonging to the same network operator through immediate establishment of internetwork agreements. The fundamental goal of multi-radio access networks is to offer an efficient mobile computing environment and to facilitate each user to seamlessly move among multi provider networks with significant consideration to quality-of-service (QoS) provision. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200902061415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090211T113000 DTEND;TZID=/Q2S/Europe/Oslo:20090211T123000 SUMMARY:Q2S Colloquium: Introduction to Spirent TestCenter - Arne Oslebo DESCRIPTION:This talk is a general introduction to the Spirent TestCenter recently bought by UNINETT and Q2S. It explains the main features of the measurement equipment and its use. Practical use of the equipment is demonstrated from the colloquium hall, including some simple tests. This equipment opens many new possibilities to everybody interested in Internet measurement, and adds to the pool of advanced measurement equipment available for us. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200902111130@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090218T111500 DTEND;TZID=/Q2S/Europe/Oslo:20090218T121500 SUMMARY:Q2S Colloquium: Quality of Service in Mobile Ad hoc Networks: A Survey - Ash Mohammad Abbas DESCRIPTION:An ad hoc network may provide cheaper ways to share information among many mobile hosts. An ad hoc network finds applications in situations where there is no centralized infrastructure such as emergency rescue missions, law enforcement, battlefield communications, online classrooms and conferences. It is desirable that an ad hoc network has a provision of quality of service (QoS). In this presentation, I shall present a survey of the research carried out by different researchers in the area of QoS provisioning in mobile ad hoc networks. I shall discuss the issues and challenges related to the provision of QoS and different solutions proposed in the literature. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200902181115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090227T141500 DTEND;TZID=/Q2S/Europe/Oslo:20090227T151500 SUMMARY:Q2S Colloquium: Adaptive Speech Quality Management in VoIP Communications - Eugene Myakotnykh DESCRIPTION:The quality of VoIP communication relies significantly on the network that transports voice packets because this network does not usually guarantee the available bandwidth, delay, and loss that are critical for real-time voice traffic. The proposed solution is to manage the voice-over-IP stream dynamically, changing parameters as needed to assure quality. The main objective of the project is to develop an adaptive speech encoding system that can be applied to conventional (telephony-grade), wideband, and, possibly full-band voice communications. This study includes the investigation and development of three key components of the system. First, to manage VoIP quality dynamically, a tool is needed to measure real-time changes in quality. The E-model, which exists for narrowband communication, may be extended to a single computational technique that measures speech quality for other types of VoIP codecs. The second system component is a variable speech-encoding algorithm. Although VoIP performance is affected by multiple codecs and network-based factors, only three factors can be managed dynamically: voice payload size, speech compression (encoding algorithm) and jitter buffer management. Using an existing adaptive jitter-buffer algorithm, voice packet-size and compression variation are studied as they affect speech quality under different network conditions. This study explains the relationships among multiple parameters as they affect speech transmission and its resulting quality. Then, based on these two components, the third system component is a novel adaptive-rate control algorithm that establishes the interaction between a VoIP sender and receiver, and manages voice quality in real-time. Simulations demonstrate that the system provides better average voice quality than traditional VoIP. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200902271415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090302T111500 DTEND;TZID=/Q2S/Europe/Oslo:20090302T121500 SUMMARY:Q2S Colloquium: Joint source-channel coding techniques for wireless multimedia communication - Christine Guillemot DESCRIPTION:Communication systems design principles so far have been mainly relying on Shannon source and channel coding separation theorem. This theorem states that source and channel performance bounds can be approached as close as desired by designing independently the source and channel coding strategies. However, this theorem holds only under asymptotic conditions. If the design of the system is constrained in terms of delay and complexity, if the sources are not stationary, or if the channels are non-ergodic, separate design and optimization of the source and channel coders can be largely suboptimal. For practical systems, joint source-channel coding as well as error resilient coding may reduce end-to-end distortion. This talk will focus on developments of source-channel decoding techniques which will be analyzed in the framework of Bayesian networks. New developments of source codes with interesting properties in terms of compression and resilience will be presented. The use of these codes and decoding tools within the H.264 video compression algorithm will be explained. Performance results with actual image and video compression systems will be illustrated. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200903021115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090318T111500 DTEND;TZID=/Q2S/Europe/Oslo:20090318T121500 SUMMARY:Q2S Colloquium: Secure sms communication. - Milivoj Simeonovski DESCRIPTION:The talk will be about a Java applet that implements an algorithm based on a quasigroups transformation which encrypts and appropriately decrypts SMS messages. The overall concept (design) of secure SMS communication will be shown. The aim of the diploma thesis was to find a way to establish secure mobile communication using textual messages (SMS) over existing GSM protocol. The challenge was to implement this algorithm using J2ME limited set of functions, supported by mobile phones and also to save limited system resources like memory and CPU. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200903181115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090424T141500 DTEND;TZID=/Q2S/Europe/Oslo:20090424T151500 SUMMARY:Q2S Colloquium: The Role of the Side Information in Wiretapped Communications. - Yanling Chen DESCRIPTION:In the modern age of digital communication, the issue of security has started to attract more attention. Both wired and wireless communications can be subject to eavesdroppers or wiretappers. Consider the following data communication problem: a transmitter wants to send a secret message to a receiver and he knows that there is a wiretapper. He writes the secret on paper using a limited amount of ink and sends it (this models transmission using limited communication resource). Along the way to the legitimate receiver, the paper becomes dirty (this models noise and interference during transmission). Assume that the wiretapper has access to an imperfect copy of the dirty paper (with even more dirt). The central question is: how much secret information can be reliably and securely sent such that (a) the legitimate receiver can correctly read the dirty paper, and (b) without leaking any secret information to the wiretapper. If the transmitter uses blank paper (this models the case without any side information known to the transmitter), and the dirt is Gaussian distributed, he can send secret information at rates up to the secrecy capacity of the Gaussian wiretap channel, as shown by Leung-Yan-Cheong and Hellman. However, to achieve reliable, efficient and especially secure communication, we wonder whether dirty paper might be a better choice than the blank paper as one would choose intuitively. This talk will explore the role of the side information in the secret communication over the wiretap channel and show that your intuition has made a right choice on this occasion. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200904241415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090504T111500 DTEND;TZID=/Q2S/Europe/Oslo:20090504T121500 SUMMARY:Q2S Colloquium: Pattern Recognition with Applications in Remote Sensing and Biomedical Informatics - Kai Wang DESCRIPTION:As a sub-topic of machine learning, pattern recognition is more about the methods of clustering raw data and the extraction of knowledge from the data. An intriguing problem in pattern recognition is the adaptations of pattern recognition algorithms for the problems to be solved. Often, multiple algorithms need to be adapted for solving a complex problem. The presenter will discuss a data clustering algorithm, fuzzy c-means, and its adaptations in solving ocean remote sensing and biomedical problems. A computer expert system has been developed to integrate multiple algorithms, and could also be used as a general-purpose image processing tool. Recent research on mobile computing in clinical setting will also be shared. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200905041115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090508T131500 DTEND;TZID=/Q2S/Europe/Oslo:20090508T141500 SUMMARY:Q2S Colloquium: IMS and Services - Kashif Imran DESCRIPTION:Kashif Imran will give a presentation of his PhD topic and a brief intro of IMS and IMS Services. He will also present the state of the art survey in this field and his possible work in this area. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200905081315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090513T110000 DTEND;TZID=/Q2S/Europe/Oslo:20090513T120000 SUMMARY:Q2S Colloquium: OBSAI interface interoperability in multivendor WiMAX base station architecture environment. - Sumanta Saha DESCRIPTION:There are different types of base station architectures. Open base station architecture initiative (OBSAI) specifications define a modular architecture for base stations as well as interfaces between the modules. These specifications will be applicable regardless of the network technology used. In this work main interface to concentrate is the RP03 interface between base band and remote RF unit. Main purpose is to analyze RP03 interoperability between vendor A base band and vendor B and/or C RF modules. This includes OBSAI interface understanding, vendor A WiMAX base station architecture understanding and possible interoperability testing in multi vendor base station architecture environment. The motivation of the work can be divided into three main categories. 1. Product management a. Ability to use any RF without a lot of testing b. Plug-n-play c. Outsource modules from any vendor 2. OBSAI standard a. Finding unclear loopholes b. Fill the gaps in standards c. Rigidity 3. WiMAX/LTE(TDM) common RF a. Will it be possible to use same RF for LTE (TDM) SM b. What standardization work needs to be done 4. Improvement proposal a. Improvement in management plane b. Improvement in data plane URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200905131100@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090529T131500 DTEND;TZID=/Q2S/Europe/Oslo:20090529T141500 SUMMARY:Q2S Colloquium: Inferring Trust based on Similarity with TILLIT - Mozhgan Tavakolifard DESCRIPTION:Network of people having established trust relations and a model for propagation of related trust scores are fundamental building blocks in many of today\'s most successful e-commerce and recommendation systems. However, the web of trust is often too sparse to predict trust values between non-familiar people with high accuracy. Trust inferences are transitive associations among users in the context of an underlying social network and may provide additional information to alleviate the consequences of the sparsity and possible cold-start problems. Such approaches are helpful, provided that a complete trust path exists between the two users. An alternative approach to the problem is advocated in this paper. Based on collaborative filtering one can exploit the like-mindedness resp. similarity of individuals to infer trust to yet unknown parties which increases the trust relations in the web. For instance, if one knows that with respect to a specific property, two parties are trusted alike by a large number of different trusters, one can assume that they are similar. Thus, if one has a certain degree of trust to the one party, one can safely assume a very similar trustworthiness of the other one. In an attempt to provide high quality recommendations and proper initial trust values even when no complete trust propagation path or user profile exists, we propose TILLIT --- a model based on combination of trust inferences and user similarity. The similarity is derived from the structure of the trust graph and users\' trust behavior as opposed to other collaborative-filtering based approaches which use ratings of items or user\'s profile. We describe an algorithm realizing the approach based on a combination of trust inferences and user similarity, and validate the algorithm using a real large-scale data-set. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200905291315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090605T131500 DTEND;TZID=/Q2S/Europe/Oslo:20090605T141500 SUMMARY:Q2S Colloquium: Analogical Trust Reasoning - Mozhgan Tavakolifard DESCRIPTION:Trust is situation-specific and the trust judgment problem with which the truster is confronted might be, in some ways, similar but not identical to some problems the truster has previously encountered. The truster then may draw information from these past experiences useful for the current situation. We present a knowledge-intensive and model-based case-based reasoning framework that supports the truster to infer such information. The suggested method augments the typically sparse trust information by inferring the missing information from other situational conditions, and can better support situation-aware trust management. Our framework can be coupled with existing trust management models to make them situation-aware. It uses the underlying model of trust management to transfer trust information between situations. We validate the proposed framework for Subjective Logic trust management model and evaluate it by conducting experiments on a large real dataset. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200906051315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090609T141500 DTEND;TZID=/Q2S/Europe/Oslo:20090609T151500 SUMMARY:Q2S Colloquium: Basic Theorems on the Backoff Process in 802.11 - Jeong-woo Cho DESCRIPTION:This paper discovers fundamental principles of the backoff process that governs the performance of IEEE 802.11. We first {\\it establish} that the so-called mean field technique, which spins off a fixed point equation, is mathematically valid for use in performance analysis of 802.11. On the basis of this, succinct equations describing the backoff distribution as a function of the collision probability $\\gamma$ are derived, which also shed light on a controversy in the field. In addition, the observation that the {\\it entropy} of the backoff process in 802.11 increases with the number of nodes leads us to see through a Poissonian character inherent in 802.11. However, it is also found that the {\\it collision} effect between nodes prevails over the {\\it Poissonian aggregation} effect in spite of its tendency to increase with the number of nodes. Based on these findings, we formulate the principle about the inter-transmission probability that lays a foundation for the short-term fairness analysis. Another principle discovered upon regular variation theory is that the per-packet backoff has a truncated {\\it Pareto-type} tail distribution with an exponent of $(\\log \\gamma)/\\log m$ ($m$ is the multiplicative factor). This reveals that the backoff process is heavy-tailed in the strict sense for $m^2 \\gamma > 1$, essentially due to collision. Moreover, we identify the long-range dependence in 802.11 and show that the inter-transmission probability undergoes a dramatic change at $\\gamma_0=1/m^2$ and falls into two qualitatively distinct categories: either approximately Gaussian or {\\it L\\\'evy} $\\alpha$-stable distribution with $\\alpha \\in (1,2)$ entailing infinite variances, {\\it leaning} tendency, and {\\it directional} unfairness. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200906091415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090612T131500 DTEND;TZID=/Q2S/Europe/Oslo:20090612T141500 SUMMARY:Q2S Colloquium: Loss-Distortion Estimation for Practical H.264/AVC Streams - Jari Korhonen DESCRIPTION:Even though several unequal erasure protection (UEP) schemes have been proposed for video streaming, it is still a challenge to define the optimal relative protection level for different data units. In this paper, we study loss-distortion modeling in realistic video streaming scenarios. The main observation is that when video streams with complex hierarchical structures and error resilience features are considered, the relative significance of different units cannot be reliably estimated from mutual dependencies between units as suggested in related research. Therefore, data units can be classified reliably into different perceptual priority classes via analysis by synthesis only. For estimating the co-impact of multiple losses, we propose a simple loss-distortion model. The model can be used for optimizing UEP in practical streaming systems. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200906121315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090828T131500 DTEND;TZID=/Q2S/Europe/Oslo:20090828T141500 SUMMARY:Q2S Colloquium: Guaranteeing Service Availability in SLAs; A Study of the Risk Associated with Contract Period and Failure Process - Andrés González DESCRIPTION:Service Level Agreements (SLAs) are a common means to define the obligations of network/service providers and users in business relationships. The terms that define the guaranteed availability for a given period are an important element of these contracts. The appropriate values selection is difficult due to the large number of variables involved, the complexities of the network and service provision and the computational challenge posed by the transient solution, as opposed to a steady state, that is needed. A common policy taken to solve it, is using the steady state availability as a reference. Nevertheless this simplification may put on risk the contract fulfillment as stochastic variation of the measured availability is significant over a typical contract period. This paper analyzes the relevance that the interval availability analysis has on SLAs, and provides suggestions to the network providers on the selection of adequate availability guarantees. The interval availability of unprotected and shared protected connections is studied under exponential and Weibull failure and repair distributions. It is observed that for a single path scenario, a small reduction of the guaranteed availability below the steady state value improve the probability to meet the requirements considerably. The same is the case for connections with shared backup protection. However performing this analysis in the transient domain is quite demanding. Hence, to simplify it, it is proposed to obtain the steady state results and introduce a safeguard factor to control that the availability guarantee is meet. For the Weibull distributed times between failures, where the shape factor is less than one (as observed in operational networks), the probability of meeting a guaranteed availability over a finite contract period, decrease more radically than for the commonly assumed Poisson failure process. This increases the importance of making a transient analysis. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200908281315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090831T141500 DTEND;TZID=/Q2S/Europe/Oslo:20090831T151500 SUMMARY:Q2S Colloquium: Activities at RMIT - Ian Burnett DESCRIPTION:na URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200908311415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090901T101500 DTEND;TZID=/Q2S/Europe/Oslo:20090901T111500 SUMMARY:Q2S Colloquium: "Quantifying the Uncertainty in Measurements for MBAC - Anne Nevin DESCRIPTION:In Measurement Based Admission Control (MBAC), the decision of accepting or rejecting a new flow is based on measurements of the current traffic situation. An in-depth understanding of the measurement error and its uncertainty is vital for the design of a robust MBAC. In this work, we study the measured parameters used by the MBAC and characterize their error. Our work differs significantly from previous work in that we find how the uncertainty in the measurements varies with the length of the observation window. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200909011015@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090904T131500 DTEND;TZID=/Q2S/Europe/Oslo:20090904T141500 SUMMARY:Q2S Colloquium: Energy-Aware Path Selection in Mobile Wireless Sensor Networks: A Dynamic Bayesian Game Approach - Chih-kuang Lin DESCRIPTION:Sensors are independent and autonomous agents that aim at completing their assigned mission. Meanwhile, they face the energy challenge from their heritage, environment and unfair design. These characteristics lead to possible selfishness as the sensor may decline to forward packets for other nodes. To address the above concern, we propose the dynamic Bayesian game approach: our algorithm derives mutually acceptable path selection strategies between the sensor and its neighbor, thereby resulting in fairer use of their energy. We validate the feasibility of this technique via analysis and simulations. The results show that it can efficiently handle the sensor\'s uncertainty, e.g., energy and mobility, while improving the energy efficiency - network lifetime. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200909041315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090911T131500 DTEND;TZID=/Q2S/Europe/Oslo:20090911T141500 SUMMARY:Q2S Colloquium: Implementing computer clapper as a tool for subjective rhythmic experiment - Rune Steinsmo Ødegård DESCRIPTION:In this presentation, Jordi will show some of his last works as a developer in the field of audio visual interactivity. Furthermore, the Computer-Clapper software will be presented, an application developed for Nima Darabi which is a programmable sequencer and impulse response detector to achieve rhythm performance metrics. Jordi will introduce MAX/MSP as an interface to develop subjective auditory and visual tests. This interface not only is used to implement human-computer subjective tests, but also will later on be used to implement the computer-clapper as a serious game. At the end Nima Darabi will finalize Jordi\'s talk to show how the observed step responses gathered from the clapper software is used to model human reaction to the tempo change by e second order damped harmonic oscillator like a damped mass spring system. Some objective quality assessment metrics will also be discussed specifically for musical interaction. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200909111315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090916T101500 DTEND;TZID=/Q2S/Europe/Oslo:20090916T111500 SUMMARY:Q2S Colloquium: Improved Registration and Segmentation for Image Analysis - Nick Kingsbury DESCRIPTION:To retrieve higher meaning from images there are often a number of preliminary tasks that need to be performed. Image registration and segmentation are two important processes that fall into this category. In this seminar I will present a new approach for registration of a 3D object with a 2D image of the same or a similar object and a new approach for segmentation of images based on texture. The new 2D-3D registration algorithm uses a similarity measure that is inherently robust to variations in intensity between the 2D and 3D objects and therefore can be used to register images of objects captured using different sensors. The new texture segmentation algorithm is based on features derived from the dual-tree complex wavelet transform of the image and is able to perform segmentation that is invariant to the scale and rotation of the texture in the image regions. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200909161015@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20090918T131500 DTEND;TZID=/Q2S/Europe/Oslo:20090918T141500 SUMMARY:Q2S Colloquium: Physical-based real-time auralization of interactive virtual environments - Dirk Schroeder DESCRIPTION:\"Auralization\" is a concept for the reproduction of sound on the basis of computer data. Auralization techniques are commonly used for adding the acoustic component to virtual reality (VR) systems. While for common applications, such as the analysis of three-dimensional simulation data, a modeling of simple sound effects usually suffices, interactive immersive environments (especially architectural applications) demand for physical-based auralization methods in order to reproduce sound pressure signals with a certain realistic behaviour. As a static environment would mostly mismatch with real world experiences, the system should also allow a high level of user interactivity to further improve the simulation in terms of immersion. This can include the dynamic modification of scene elements, e.g. the opening and closing of doors and windows, the change of acoustic material properties of surfaces, and even a modification of the geometry itself, e.g. adding new objects or moving walls. A hybrid concept for the simulation of sound propagation in rooms will be presented which is incorporated into the real-time room acoustics simulation software RAVEN. RAVEN uses a deterministic image source method for determining early specular reflections and a stochastic ray tracer for computing the reverberant sound field, i.e. diffuse and late specular reflections. Both approaches account for the simulation of sound diffraction, too. The software is incorporated into the 3D sound rendering system of RWTH Aachen University\'s CAVE and is used for any room acoustics simulation as a network service. See also: http://www.akustik.rwth-aachen.de/Forschung/Projekte/raven Demo section at the end of this website. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200909181315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091001T111500 DTEND;TZID=/Q2S/Europe/Oslo:20091001T121500 SUMMARY:Q2S Colloquium: Broadband music collaboration and virtual acoustics research projects at CIRMMT - Rune Steinsmo Ødegård DESCRIPTION:na URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200910011115@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091009T131500 DTEND;TZID=/Q2S/Europe/Oslo:20091009T141500 SUMMARY:Q2S Colloquium: Managing availability in wireless inter domain access - Eirik Larsen Følstad DESCRIPTION:This paper deals with how the availability of wireless/cellular access networks depend on the cooperation between the operators as well as with transmission network operators and professional land lords. The forthcoming 4G network will consist of diverse sets of wireless/cellular networks integrated into IP-based networks. Mobility, QoS and seamless handover between the networks are key features. In [1] the concept of Always Best Connected is defined as means that the user is connected through the best available device and access technology at all times. Availability of the access is fundamental for QoS and critical services (e.g. emergency services, health services) are more and more dependent of wireless/mobile access. Availability can be increased by utilization of several accesses through seamless handover and/or multihoming. Usually, the availability has been calculated assuming independencies between the access network operators, but in this paper we show that the actual cooperation between the market actors has significant impact on the availability. We propose a solution by usage of the IMH 802.21 framework to build and distribute network topologyinformation with availability estimates allowing to predict the overall availability for the access networks accessible as one of the criteria for a handover decision. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200910091315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091019T141500 DTEND;TZID=/Q2S/Europe/Oslo:20091019T151500 SUMMARY:Q2S Colloquium: Complex Wavelets: What are they and what can they do? - Nick Kingsbury DESCRIPTION:This talk will describe the Dual Tree Complex Wavelet Transform (DTCWT), which is a form of discrete wavelet transform that generates complex coefficients by using two trees of wavelet filters to obtain their real and imaginary parts. This introduces limited redundancy and allows the transform to provide the important properties of shift invariance and good directional selectivity. We will concentrate on applications of the DT CWT to datasets in 2-D (images) and 3-D (volumetric data). Typical applications include denoising, regularisation (for deconvolution), displacement estimation and registration, and object recognition. Examples of some of these applications will be given. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200910191415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091023T131500 DTEND;TZID=/Q2S/Europe/Oslo:20091023T141500 SUMMARY:Q2S Colloquium: Interconnecting IMS and Web Services - Performance aspects - Kashif Imran DESCRIPTION:The Telecomm Operators (Telcos) are facing problems in increasing their revenues from traditional voice and data services. In order to compensate for the declining revenues, the Telcos have to look for newer content-based and application-based multi-media services as a way to boost revenues. One solution is to bring social communication Web services (like Facebook, Twitter, Yahoo Msg etc) to the mobile users. In order to provide such services IP Multimedia Sub-system (IMS) is a suitable candidate; it can provide multi-media services with guaranteed Quality of Service (QoS). In this paper we have presented generalized performance scenarios which can be implemented on the IMS and WS working together. We have also discussed the different performance issues which they may experience in multi-provider network and have also pointed out different scenarios where they may face performance bottlenecks. In the end we have discussed the possible solutions to these problems and have also given our intended work in future. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200910231315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091030T131500 DTEND;TZID=/Q2S/Europe/Oslo:20091030T141500 SUMMARY:Q2S Colloquium: An objective video quality metric based on spatiotemporal distortion - Weisi Lin DESCRIPTION:This work proposes an objective video quality metric based on an analysis of spatial and temporal distortions. Spatial quality features extracted from the spatiotemporal region of reference and distorted videos are used to express the spatial distortion. Temporal distortion, caused by frame freezing resulting from a packet loss, is derived from the spatial distortion before and after the frozen frames. The overall quality is predicted according to the weighted combination of qualities over all the temporal regions. The experimental results with respect to the subjective measurements demonstrate the fast computation and promising performance of the proposed model compared with existing methods. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200910301315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091117T140000 DTEND;TZID=/Q2S/Europe/Oslo:20091117T150000 SUMMARY:Q2S Colloquium: Inter-provider routing and service architectures for the future Internet - Stefano Secci DESCRIPTION:We present various technical solutions to improve the level of collaboration among providers in support of inter-provider network services. By an in-depth analysis of recent Internet routing traces, we show that the current inter-domain (connection- less) routing suffers from a lack of coordination that produces inefficiencies and frequent route deviations. With respect to this issue, relying on concepts of non-cooperative game theory, we propose coordination strategies to improve the current BGP routing across peering settlements, while preserving the providers\' independence and respective interests. We show that their implementation can avoid congestion on peering links, reduce significantly the routing cost and successfully control the route deviations. The mathematical model can be extended to support a new form of peering agreement extended to multiple providers, but its adoption may appear too weak with respect to alternative solutions able to guarantee end-to- end cross-provider Quality of Service (QoS). The support of strict end-to-end QoS constraints for added-value services imposes, indeed, a higher level of collaboration on the multi-provider agreement. It is required to reserve resources for own services in other providers\' networks. These requirements bring towards a new interconnection model, the \"provider alliance\", as a cooperative framework that providers shall deploy to allow dynamic connection-oriented service routing and provisioning. We define the functional architecture of a service plane managing service-related data within the provider alliance, together with the instantiation and activation of multi-provider tunnel and circuit services. We highlight the required protocol extensions for the distributed (router-level) path computation and the dynamic resource reservation, which have been implemented and validated in a testbed. We define, moreover, specific AS-level routing algorithms that scale with the proposed model, supporting pre- computation and directional transit metrics. Finally, we show how providers shall cooperate also to statically reserve link resources, in an optimal and distributed fashion, modelling the economical incentives and the strategic position of each provider in such a cooperation with the application of concepts from cooperative game theory (precisely, the Shapley Value concept). URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200911171400@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091127T131500 DTEND;TZID=/Q2S/Europe/Oslo:20091127T141500 SUMMARY:Q2S Colloquium: Analysis on the Perceptual Impact of Bit Errors in Practical Video Streaming Applications - Jari Korhonen DESCRIPTION:In video streaming applications, there are two main sources of distortion in video quality: source distortion caused by video compression and channel distortion derived from failures in transmission, including packet losses and bit errors. The impact of bit errors on the perceived video quality depends on several different factors, such as error resilience of the data format itself, used error concealment mechanism and characteristics of the bit error pattern. In this paper, we have studied these different influencing factors from different perspectives, ranging from telecommunications to video signal processing and subjective quality assessment. We show that our results are useful for assessment and development of schemes to optimize bit error resilience in video streaming and broadcasting applications. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200911271315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091204T131500 DTEND;TZID=/Q2S/Europe/Oslo:20091204T141500 SUMMARY:Q2S Colloquium: On Schemes for Supporting QoS and Mobility in Heterogeneous Networks - Fazal Karam DESCRIPTION:The significance of quality of service (QoS) can be largely attributed to the recent evolution of wireless networks and its dynamic nature due to wide heterogeneity of networks and services as shown in Figure 1. Efficient access technologies are relevant, such as WLAN, WiMAX and HSPA. These are mixed with multiple providers on the core network side as well. To provide a good user experience, it is needed to support seamless handover and optimal decision for choosing the access networks. These are based on applications, user\'s preferences and network QoS criteria in different service providers, transmission media and implemented mechanisms. we proposes a scheme to provide service mobility with required QoS for different applications in heterogeneous access networks. Some existing schemes and proposed schemes are surveyed and compared with respect to key QoS-related mechanisms and capabilities. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200912041315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20091214T110000 DTEND;TZID=/Q2S/Europe/Oslo:20091214T120000 SUMMARY:Q2S Colloquium: Using realtime animation for storytelling - Friedrich Kirschner DESCRIPTION:In his talk, Friedrich will discuss some of his work in animation and computer graphics, from modifications of game-engines and scanning objects with milk and Lego, to new ways of creating animated movies and live realtime animation productions. For more information on Friedrich\'s work, please go to www.zeitbrand.net URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:200912141100@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100108T141500 DTEND;TZID=/Q2S/Europe/Oslo:20100108T151500 SUMMARY:Q2S Colloquium: The JPEG 2000 Suite of standards - Peter Schelkens DESCRIPTION:The Joint Photographic Experts Group (JPEG) committee is a joint working group of the International Standardization Organization (ISO) and the International Electrotechnical Commission (IEC). Inspired by technology and market evolutions, i.e. the advent of wavelet technology and need for additional functionality such as scalability, the JPEG committee launched in 1997 a new standardization process that would result in 2000 in a new standard: JPEG 2000. JPEG 2000 is a collection of standard parts, which together shape the complete toolset. Currently, the JPEG 2000 standard is composed out of 13 parts addressing a plethora of applications. In this presentation, we review recent standardization initiatives in this context and address application domains such as broadcasting and digital cinema. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201001081415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100122T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100122T141500 SUMMARY:Q2S Colloquium: Cryptographic Protocol Analysis of AN.ON - Benedikt Westermann DESCRIPTION:The work presents a cryptographic analysis of AN.ON\'s anonymization protocols. We have discovered three flaws of differing severity. The first is caused by the fact that the freshness of the session key was not checked by the mix. This flaw leads to a situation where an external attacker is able to perform a replay attack against AN.ON. A second, more severe, error was found in the encryption scheme of AN.ON. An internal attacker controlling the first mix in a cascade of length two is able to de-anonymize users with high probability. The third flaw results from the lack of checks to ensure that a message belongs to the current session. This enables an attacker to impersonate the last mix in a cascade. The flaws we discovered represent errors that, unfortunately, still oc- cur quite often and show the importance of either using standardized crytpographic protocols or performing detailed security analyses. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201001221315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100223T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100223T141500 SUMMARY:Q2S Colloquium: QoS / Monitoring in a Broadcast network - Torkel Thoresen DESCRIPTION:Agenda: - Telenor Broadcast - QoS in a Broadcast Network - Service Level Agreement - Service Level Performance Measurement - "Black box" principle - Case-in-point: The BIPP (Broadcast IP Platform) URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201002231315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100430T130000 DTEND;TZID=/Q2S/Europe/Oslo:20100430T140000 SUMMARY:Q2S Colloquium: On the Modeling of Delay and Burstiness for Calculating Throughput - Kashif Mahmood DESCRIPTION:This work presents a method for calculating the throughput of a network considering the bursty nature and delay requirements of real sources by using the established results in the area of guaranteed rate scheduling. The network of which the throughput is derived, implements aggregate scheduling which has been tipped as the solution to address scalability issues in large scale networks. The method is quite general and is applicable to a wide range of arrival and services processes. The study is useful in the domain of network information theory for estimating the amount of traffic that can be accommodated within a network with a specified bit rate and at the same time ensuring that QoS criteria are met along the path traversed by the input flow. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201004301300@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100604T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100604T141500 SUMMARY:Q2S Colloquium: Dynamic Sharing Mechanism for Guaranteed Availability in MPLS Based Networks - Andrés González DESCRIPTION:This study proposes an algorithm for allocating connections with bandwidth and availability requirements in a telecommunication network where the connections may share resources in their backup paths. The allocation is dynamic in the sense that allocation requests have random arrival times, source and destinations, and allocated connections have a random duration. The algorithm has been designed for core backbone networks with continuous bandwidth distribution, like for example MPLS networks. An efficient bandwidth utilization was obtained by an intelligent sharing mechanism that takes into account the properties of networks with continuous bandwidth allocation. The problem may be formulated as an NIP (Nonlinear Integer Programming) problem. However, due to the well known complexity and scalability limitations in solving this kind of problems, the solution is based on heuristic procedures. A performance comparison with previously published algorithms is carried out for some \"reference networks\", demonstrating a substantially better resource usage. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201006041315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100608T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100608T141500 SUMMARY:Q2S Colloquium: On the Validity of the Fixed Point Equation and Decoupling Assumption for Analyzing the 802.11 MAC Protocol - Jeong-woo Cho DESCRIPTION:Performance evaluation of the 802.11 MAC protocol is classically based on the decoupling assumption, which hypothesizes that the backoff processes at different nodes are independent. A necessary condition for the validity of this approach is the existence and uniqueness of a solution to a fixed point equation. However, it was also recently pointed out that this condition is not sufficient; in contrast, a necessary and sufficient condition is a global stability property of the associated ordinary differential equation. Such a property was established only for a specific case, namely for a homogeneous system (all nodes have the same parameters) and when the number of backoff stages is either 1 or infinite and with other restrictive conditions. In this paper, we give a simple condition that establishes the validity of the decoupling assumption for the homogeneous case. We also discuss the heterogeneous and the differentiated service cases and show that the uniqueness condition is not sufficient; we exhibit one case where the fixed point equation has a unique solution but the decoupling assumption is not valid. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201006081315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100610T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100610T141500 SUMMARY:Q2S Colloquium: Does Trust Matter for User Preferences? A study on Epinions ratings - Pern Hui Chia DESCRIPTION:Recommender systems have evolved during the last few years into useful online tools for assisting the daily e-commerce activities. The majority of recommender systems predict user preferences relating users with similar taste. Prior research has shown that trust networks improve the performance of recommender systems, predominantly using algorithms devised by individual researchers. In this work, omitting any specific trust inference algorithm, we investigate how useful it might be if explicit trust relationships (expressed by users for others) are used to select the best neighbours (or predictors), for the provision of accurate recommendations. We conducted our experiments using data from Epinions.com, a popular recommender system. Our analysis indicates that trust information can be helpful to provide a slight performance gain in a few cases especially when it comes to the less active users. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201006101315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100614T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100614T141500 SUMMARY:Q2S Colloquium: Improving Image Quality Assessment with Modeling Visual Attention - Weisi Lin DESCRIPTION:Visual attention is an important attribute of the human visual system (HVS), while it has not been explored in image quality assessment adequately. This paper investigates the capabilities of visual attention models for image quality assessment in different scenarios: two-dimensional images, stereoscopic images, and Digital Cinema setup. Three bottom-up attention models are employed to detect attention regions and find fixation points from an image and compute respective attention maps. Different approaches for integrating the visual attention models into several image quality metrics are evaluated with respect to three different image quality datasets. Experimental results demonstrate that visual attention is an important factor that can not be ignored in improving the performance of image quality metrics in perceptual quality assessment. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201006141315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100618T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100618T141500 SUMMARY:Q2S Colloquium: MQQ Analysis - Rune Steinsmo Ødegård DESCRIPTION:MQQ is a multivariate cryptosystem based on multivariate quadratic quasigroups and the Dobbertin transformation [1]. The cryptosystem was broken both by Gröbner bases computation and MutantXL [2]. The complexity of Gröbner bases computation is exponential in the degree of regularity, which is the maximum degree of polynomials occurring during the computation. The authors of [2] observed that the degree of regularity for solving the MQQ system is bounded from above by a small constant. In this paper we go one step further in the analysis of MQQ. We explain why the degree of regularity for the MQQ system is bounded. The main result of this paper is how the complexity of solving the MQQ system is the minimum complexity of solving just one quasigroup block and solving the Dobbertin transformation. Furthermore, we show that the degree of regularity for solving the Dobbertin transformation is bounded from above by the same constant as the bound on the MQQ system. We then investigate the strength of a tweaked MQQ system where the input to the Dobbertin transformation is replaced with random linear equations. We find that the degree of regularity for this tweaked system varies both in the size of the quasigroups and the number of variables. We conclude that if a suitable replacement for the Dobbertin transformation is found, MQQ can possibly be made strong enough to resist pure Gröbner attack for correct choices of quasigroups size and number of variables. [1] Danilo Gligoroski, Smile Markovski, and Svein Johan Knapskog. Multivariate quadratic trapdoor functions based on multivariate quadratic quasigroups. In MATH\'08: Proceedings of the American Conference on Applied Mathematics, pages 44-49, Stevens Point, Wisconsin, USA, 2008. World Scientific and Engineering Academy and Society (WSEAS). [2] Mohamed Saied Mohamed, Jintai Ding, Johannes Buchmann, and Fabian Werner. Algebraic attack on the MQQ public key cryptosystem. In CANS \'09: Proceedings of the 8th International Conference on Cryptology and Network Security, pages 392-401, Berlin, Heidelberg, 2009. Springer-Verlag. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201006181315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100621T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100621T141500 SUMMARY:Q2S Colloquium: Distinguishers for the Compression Function and Output Transformation of Hamsi-256 - Rune Steinsmo Ødegård DESCRIPTION:Hamsi is one of 14 remaining candidates in NIST\'s Hash Competition for the future hash standard SHA-3. Until now, little analysis has been published on its resistance to differential crypt- analysis, the main technique used to attack hash functions. We present a study of Hamsi\'s resistance to differential and higher- order differential cryptanalysis, with focus on the 256-bit version of Hamsi. Our main results are efficient distinguishers and near-collisions for its full (3-round) compression function, and distinguishers for its full (6-round) finalization function, indicating that Hamsi\'s building blocks do not behave ideally. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201006211315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100624T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100624T141500 SUMMARY:Q2S Colloquium: MBAC: Impact of the Measurement Error on Key Performance Issues - Anne Nevin DESCRIPTION:In Measurement Based Admission Control (MBAC), the decision of accepting or rejecting a new flow is based on measurements of the current traffic situation. Since MBAC relies on measurements, an in-depth understanding of the measurement error and how it is affected by the underlying traffic is vital for the design of a robust MBAC. In this work, we study how the measurement error impacts the admission decision, in terms of 'false rejections' and 'false acceptances', and the consequence this has for the MBAC performance. A slack in bandwidth must be added to reduce the probability of false acceptance. When determining the size of this slack, the service provider is confronted with the trade-off between maximizing useful traffic and reducing useless traffic. We show how the system can be provisioned to meet a predefined performance criteria. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201006241315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100625T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100625T141500 SUMMARY:Q2S Colloquium: Current Work on Online QoS Estimation - Guoqiang Hu DESCRIPTION:In the Internet, premium services require to keep a very small delay tail probability with respect to some delay threshold. Such a small probability is difficult to measure in real time due to the large measurement variability. Practical approaches measure the traffic statistics instead and derive the tail probability by queueing analysis. In this paper, we show that an accurate estimator based on in-depth queueing analysis can amplify the measurement errors and cause robustness problem. A simple and less-accurate estimator is proposed to achieve much better robustness while still keeping a satisfying accuracy. The balance between the accuracy and robustness is thus not only an issue of parameter configuration for an estimator, but also a crucial point in designing the method for online estimation. This insight illuminates a potential new way for the development of online tail probability estimators. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201006251315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100730T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100730T141500 SUMMARY:Q2S Colloquium: Performance Analysis of a Cognitive Radio Network with Stochastic Network Calculus - Yuehong Gao DESCRIPTION:In this research topic, the stochastic network calculus is used to analyze the performance bounds for a cognitive radio network with two classes of input traffic. Firstly, a simplified ideal system model is analyzed. The stochastic service curves for primary users and secondary users are obtained, based on which the performance bounds are derived under two methods, i.e., min-plus convolution and independent case analysis. Secondly, the impact of spectrum sensing errors and retransmission schemes are introduced into the simplified model, and further analysis are made. Numerical and simulation results are compared and presented to better illustrate the results. At last, possible improvements in the future research plan are discussed. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201007301315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100910T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100910T141500 SUMMARY:Q2S Colloquium: Towards Fair Indictment for Data Collection with Self-Enforcing Privacy - Mark Stegelmann DESCRIPTION:Recently, multiple cryptographic schemes for data collection with self-enforcing privacy were proposed by Golle et al. The schemes allow participants of electronic polls to prove a pollster\'s guilt if he distributes responses. Introducing punitive damages for such misbehaviour creates incentives for a pollster to protect the respondents\' privacy. To achieve fairness, a proof must be feasible if and only if a pollster in- deed leaked information. This paper analyses the scheme proposed for self-enforcing privacy with no release of data. Neither parameter publication nor cooperative indictment have been defined up to now. We show that both are of key importance to ensure fairness and describe potential attacks of a malicious pollster. After a detailed analysis, we propose two extensions preventing such actions. In addition, a possibility for the pollster to gain an unfair advantage in the basic scheme is identified and according checks put forward. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201009101315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20100930T131500 DTEND;TZID=/Q2S/Europe/Oslo:20100930T141500 SUMMARY:Q2S Colloquium: MBAC: The Measurement Error with Non-Homogeneous Flows - Anne Nevin DESCRIPTION:In Measurement Based Admission Control (MBAC), the decision of accepting or rejecting a new flow is based on measurements of the current traffic. Since MBAC relies on measurements, an in-depth understanding of the measurement error and how it is affected by the underlying traffic is vital for the design of a robust MBAC. The consequence of the measurement error is that flows are accepted in error, a false acceptance, and rejected in error, a false rejection. In this paper, the focus is on the prevention of false acceptance as the consequence is QoS violations and a service that may be of little use to the customers. Non-homogeneous flows cause increased complexity for the MBAC algorithm and also for the measurement process. The concept of similar flows is introduced, which is a restriction to simplify the analytical expressions in a non-homogeneous flow environment. This work differs significantly from previous work in the literature in that the measurement error is characterized as it abates with the length of the measurement window. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201009301315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20101008T131500 DTEND;TZID=/Q2S/Europe/Oslo:20101008T141500 SUMMARY:Q2S Colloquium: A Mixed Integer Programming Model for Multicast Routing with Multipath Delay Jitter Reduction - Matin Bagherpour DESCRIPTION:Multipath routing is the technique of assigning multiple paths to destinations which is believed to be beneficial to satisfy QoS requirements, especially when there are strict delay requirements and violation from Service Level Agreement (SLA) has significant revenue loss. However, it has not yet analytically been analyzed that how multipath routing can improve different QoS parameters. In this paper, first we propose a mixed integer programming model to minimize reservation costs while satisfying end-to-end delay constraint by letting to reserve at most two redundant paths for each multicast destination. Since the mathematical model is complicated and highly nonlinear, we propose a heuristic algorithm to find redundant paths to satisfy delay requirements. To guarantee delay jitter reduction, redundant paths must be maximally disjoint-minimal delay different. We use simulation experiments to survey the effect of multipath routing on QoS for different network topologies and parameter settings and compare results to show performance of proposed model. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201010081315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20101109T131500 DTEND;TZID=/Q2S/Europe/Oslo:20101109T141500 SUMMARY:Q2S Colloquium: Analyzing Causes of Failures in the Global Research Network Using Active Measurements + Summary form RNDM 2010 - Otto J Wittner DESCRIPTION:Presentation of paper published at RNDM 2010. The paper is available in the Q2S-database https://www.q2s.ntnu.no/all_publications/open/2010/Paper_rev/Analyzing%20 Causes%20of%20Failures_EDAS.pdf A summary of impressions from the RNDM 2010 workshop will also be presented. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201011091315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20101112T131500 DTEND;TZID=/Q2S/Europe/Oslo:20101112T141500 SUMMARY:Q2S Colloquium: A Survey of QoS Multicast in Ad Hoc Networks - Viet Thi Minh Do DESCRIPTION:This survey on Quality of Service (QoS) in multicast ad hoc networks uses a framework based on the mechanisms in three important elements: resource estimations, multicast tree/mesh administration, and multicast routing. Our contribution is an exploration of the design space and an identification of areas that have not been fully explored. We discuss the design space of central mechanisms and classify proposed QoS multicast schemes according to the mechanisms they used. In addition, we summarize the scenarios used for evaluating their performance. Furthermore, we identify issues, mechanisms, and scenarios that have not been fully investigated in existing works. The paper provides a coherent understanding of design principles, conceptual operation, and evaluated scenarios of schemes designed for QoS multicast application in mobile ad hoc networks (MANETs). It also outlines new areas for future research in this field. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201011121315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20101203T131500 DTEND;TZID=/Q2S/Europe/Oslo:20101203T141500 SUMMARY:Q2S Colloquium: Analysis of Dependencies Between Failures in the UNINETT IP Backbone Network - Andrés González DESCRIPTION:Dependencies between failures in operational networks may have a huge impact on their reliability and availability. In this paper we analyze failure logs to identify simultaneous and potentially correlated failures in routers and links of an IP backbone network. We show that the actual behavior of failure processes does not support the independence assumption commonly used in theoretical studies. Scatter plots are presented to visualize the failure processes, and it is seen that geographical adjacency has a pronounced effect. The existence of high correlation coefficients and high autocorrelation in some failure processes was observed. A formal analysis confirms this. The consequences of these dependencies on the provisioning of guaranteed availability are briefly discussed. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201012031315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20101210T131500 DTEND;TZID=/Q2S/Europe/Oslo:20101210T141500 SUMMARY:Q2S Colloquium: Towards Analysis of Intra-Flow Contention in Multi-hop Wireless Networks - Jie Xu DESCRIPTION:Based on whether the competing active nodes are forwarding packets of the same flow, the channel access contention in multi-hop wireless networks can be classified into intra-flow contention and inter-flow contention. In this paper, we analyze the effect of intra-flow contention on multi-hop network performance. First, we demonstrate that intra-flow contention makes up a large proportion of contention in the network and may severely degrade the network performance. Then, to understand the performance improvement by eliminating intra-flow contention, we consider an ideal MAC based on 802.11 DCF where intra-flow contention is eliminated. We analyze the performance of the ideal MAC by proposing a three-dimensional Markov model. Furthermore, we present an approximate implementation of the ideal MAC based on simple modifications to 802.11 DCF. Finally, extensive simulations are performed and the results validate the proposed model and reveal the performance improvement by eliminating intra-flow contention. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201012101315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110318T131500 DTEND;TZID=/Q2S/Europe/Oslo:20110318T141500 SUMMARY:Q2S Colloquium: Analysis of Failures Characteristics in the UNINETT IP Backbone Network + Presentation of some statistical tools for the analysis of measured data - Andrés González DESCRIPTION:Core backbone networks must be designed to guarantee high levels of availability. Any interruption in the services that they provide may have massive consequences. For this reason there is a huge interest in developing methods able to keep the network robustness in the desired level. For the design of these methods are used models that need input information such as the operational state of network components which are stochastic variables. The aim of this paper is to provide an insight into the core networks behavior based on real operational data in order to help future related works to take more realistic assumptions. Based on failure logs provided by UNINETT we analyze availability levels and failure intensities in routers and links. We show that links may be classified in three groups with different properties. Additionally we observe that some links have similar dependability features than routers, making the perfect node assumption used on many related studies not correct. Finally, there were used parametrization techniques in order to fit the empirical processes with well-known distributions. We observe that the Weibull assumption that is traditionally used to model link failures processes fits properly the behavior of routers and short distance links but for the case of long distance fibers the gamma distribution seems to fit better. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201103181315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110523T130000 DTEND;TZID=/Q2S/Europe/Oslo:20110523T140000 SUMMARY:Q2S Colloquium: Creating Interactive Multimedia Works with Bio-data - Claudia Robles Angel DESCRIPTION:This paper deals with the usage of bio-data from performers to create interactive multimedia performances or installations. It presents this type of research in some art works produced in the last fifty years (such as Lucier\'s Music for a Solo Performance, from 1965), including two interactive performances of my authorship, which use two different types of bio-interfaces: on the one hand, an EMG (Electromyography) and on the other hand, an EEG (electroencephalography). The paper explores the interaction between the human body and real-time media (audio and visual) by the usage of bio- interfaces. This research is based on biofeedback investigations pursued by the psychologist Neal E. Miller in the 1960s, mainly based on finding new methods to reduce stress. However, this article explains and shows examples in which biofeedback research is used for artistic purposes only. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201105231300@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110527T130000 DTEND;TZID=/Q2S/Europe/Oslo:20110527T140000 SUMMARY:Q2S Colloquium: Analysis on the capacity of a cognitive radio network under delay constraints - Yuehong Gao DESCRIPTION:In this paper, performance analysis of a cognitive radio network is conducted. In the network, there is imperfect sensing and the wireless channel is a Gilbert- Elliott channel. The focus is on the network\'s capacity in serving traffic with delay constraints. Specifically, the maximum traffic arrival rates of both primary users and secondary users, which the network can support with guaranteed delay bounds, are investigated. The analysis is based on stochastic network calculus. A general relationship between delay bounds, traffic patterns and important characteristics such as spectrum sensing errors and channel fading of the cognitive radio network is derived. This relationship lays a foundation for finding the capacity under different traffic scenarios. Two specific traffic types are exemplified, namely periodic traffic and Poisson traffic. Analytical results are presented in comparison with simulation results. The comparison shows a good match between them, validating the analysis. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201105271300@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110601T131500 DTEND;TZID=/Q2S/Europe/Oslo:20110601T141500 SUMMARY:Q2S Colloquium: Reproduction of Independent Soundfields In a Multizone Surround System - Nasim Radmanesh DESCRIPTION:While higher order ambisonic approaches can be used to generate multiple zone soundfields, this paper adopts a Least Squares matching approach which provides a more flexible formulation. The base approach, computes speaker weights which allow for the placement of single sources in the soundfield. In this paper the approach is extended firstly to two multi-frequency sources and then to narrowband speech signals. The results for multi-frequency sources explore the zonal soundfield errors resulting from varied source positions. For speech signals, the approach provides a potential solution for multiple conversation reproduction in a multi user environment. The paper results indicate that the approach is feasible for zones which do not suffer occlusion effects from other zones. However, for more versatile multizone soundfield reproduction a 3D approach is recommended. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201106011315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110621T131500 DTEND;TZID=/Q2S/Europe/Oslo:20110621T141500 SUMMARY:Q2S Colloquium: Why should I blog? - Anne Nevin DESCRIPTION:What do you think about blogging? Is blogging simply a big waste of time or...... Do you think blogging can be useful for your PhD research or research in general? URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201106211315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110624T131500 DTEND;TZID=/Q2S/Europe/Oslo:20110624T141500 SUMMARY:Q2S Colloquium: On the Flow Level Delay of a Spatial Multiplexing MIMO Wireless Channel - Kashif Mahmood DESCRIPTION:The MIMO wireless channel offers a rich ground for quality of service analysis. In this work, we present a stochastic network calculus analysis of a MIMO system, operating in spatial multiplexing mode, using moment generating functions (MGF). We quantify the spatial multiplexing gain, achieved through multiple antennas, for flow level quality of service (QoS) performance. Specifically we use Gilbert-Elliot model to describe individual spatial paths between the antenna pairs and model the whole channel by an $N$-State Markov chain, where $N$ depends upon the degrees of freedom available of the MIMO system. We derive probabilistic delay bounds for bursty channels and show the impact of increasing the number of antennas on the delay bounds under various conditions, such as signal strength and fading speed. Further we present results for multi-hop scenarios under statistical independence. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201106241315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110902T141500 DTEND;TZID=/Q2S/Europe/Oslo:20110902T151500 SUMMARY:Q2S Colloquium: Use of GPUs in acoustic modeling and audio DSP - Nasim Radmanesh DESCRIPTION:All room acoustic modeling techniques are computationally demanding due to the underlying complexity of sound propagation. Traditionally, all the modeling methods have been implemented for the central processing unit (CPU) of the computer. Recent trends in terms of programmable many-core processors or graphics processing units (GPU) is resulting in a paradigm shift. Modern GPUs are massively parallel processors with a different memory hierarchy, whose peak computational performance can be 10X more than that of current CPUs. In this presentation, Lauri will give an overview of GPU architectures and address issues in designing suitable algorithms that map well to GPU architectures. The room acoustic modeling and auralization techniques are especially discussed in the light of possible GPU-based implementations. He also gives a brief overview of recent advances in parallelization of real-time signal processing operations for audio, especially from auralization point-of-view. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201109021415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110923T131500 DTEND;TZID=/Q2S/Europe/Oslo:20110923T141500 SUMMARY:Q2S Colloquium: A Practical Complexity-Theoretic Analysis of Mix Systems - Vinh Pham DESCRIPTION:The Minimal-Hitting-Set attack (HS-attack) is a well-known passive intersection attack against Mix-based anonymity systems, applicable in cases where communication behaviour is non-uniform and unknown. The attack allows an observer to identify uniquely the fixed set of communication partners of a particular user by observing the messages of all senders and receivers using a Mix. Whilst the attack makes use of a provably minimal number of observations, it also requires solving an NP-complete problem. No prior research, to our knowledge, analyses the average complexity of this attack as opposed to its worst case. We show that the average complexity of the HS-attack can vary between a worst- case exponential complexity and a linear-time complexity according to the Mix parameters. We provide a closed formula for this relationship, giving a precise measure of the resistance of Mixes against the HS-attack in practice, and allowing adjustment of their parameters to reach a desired level of strength. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201109231315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20110930T131500 DTEND;TZID=/Q2S/Europe/Oslo:20110930T141500 SUMMARY:Q2S Colloquium: Investigating \'Quality of Experience\' (QoE): an interdisciplinary perspective - Katrien De Moor DESCRIPTION:The search for approaches that enable dynamic Quality of Experience- measurement in the context of ubiquitous and \'always on\' multimedia consumption is both crucial and challenging. On the one hand, there is a growing awareness in the QoE community that human experiences do not take place in a vacuum: a wide range of objective and highly subjective dimensions may influence a user\'s Quality of Experience. On the other hand, this awareness is not reflected in the traditional objective and subjective testing approaches. These are still predominantly technology-oriented, do not (sufficiently) reflect the multi-dimensional character of QoE and fail to grasp users\' experiences in the actual contexts in which they are taking place. QoE - being a complex and multi-faceted concept - should therefore be investigated from an interdisciplinary perspective. In this short talk, I will say a few words about my background, personal research focus and motivation for being here at Q2S. Additionally, I will show some concrete examples of interdisciplinary QoE-research from previous studies that I have been involved in. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201109301315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20111017T141500 DTEND;TZID=/Q2S/Europe/Oslo:20111017T151500 SUMMARY:Q2S Colloquium: Perceptual Quality Evaluation: An Overview and Several New Contributions - Weisi Lin DESCRIPTION:The first part of this talk gives an up-to-date overview on research in the areas related to quality evaluation for images and video. The ultimate objective of the resultant metrics aims at measuring and predicting picture quality according to the human perception. A number of frequently-used building blocks of the metrics are discussed: signal decomposition; just-noticeable distortion (JND); visual attention (VA); and common feature and artifact detection. Afterwards, different types of existing metrics are to be presented, and further discussion will be given toward feature pooling and viewing condition. Six often-used image metrics are also compared with seven public image databases (totally 3832 test images). We highlight the most significant research work for each topic and provide the links to the relevant literature. In the second part of the talk, several pieces of recent research (during the past two years) in the area by our team will be introduced and discussed. These include improved JND and VA models, and the use of machine learning in both a single metric and multi- metrics fusion; we have also performed evaluation based upon Fourier transform, 2D mel-cepstrum, free-energy modeling and Singular Value Decomposition; applications will be presented for watermarking, graphic rendering and image retargeting. We hope to use these to stimulate further discussion and explore opportunities for collaboration. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201110171415@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20111111T131500 DTEND;TZID=/Q2S/Europe/Oslo:20111111T141500 SUMMARY:Q2S Colloquium: Colonel Blotto in the Phishing War - Pern Hui Chia DESCRIPTION:Phishing exhibits characteristics of asymmetric conflict and guerrilla warfare. Phishing sites, upon detection, are subject to removal by takedown specialists. In response, phishers create large numbers of new phishing attacks to evade detection and stretch the resources of the defenders. We propose the Colonel Blotto Phishing (CBP) game, a twostage Colonel Blotto game with endogenous dimensionality and detection probability. We find that the optimal number of new phishes to create, from the attacker\'s perspective, is influenced by the degree of resource asymmetry, the cost of new phishes, and the probability of detection. Counter-intuitively, we find that it is the less resourceful attacker who would create more phishing attacks in equilibrium. And depending on the detection probability, an attacker will vary his strategies to either create even more phishes, or to focus on raising his resources to increase the chance he will extend the lifetime of his phishes. We discuss the implications to anti-phishing strategies and point out that the game is also applicable to web security problems more generally. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201111111315@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20120110T140000 DTEND;TZID=/Q2S/Europe/Oslo:20120110T150000 SUMMARY:Q2S Colloquium: Quality Evaluation of Long Duration Audiovisual Content - Adam Borowiak DESCRIPTION:Long-term audiovisual quality assessment is still an unexplored field of science. This is due to a very limited number of internationally accepted recommendations in the field. To be more specific only one such recommendation exists. In our work we present an alternative methodology for the evaluation of perceived quality for long duration audiovisual material. This method allows the investigation of unexplored dependencies between perceived quality and impairment variations over extended periods of time. Instead of providing quality scores on predefined rating scales, assessors are asked to adjust the quality level of the displayed content themselves, whenever a degradation in perceived quality occurs. This method approaches the problem of quality evaluation from a different perspective than the existing methods, which might be valuable for future research. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201201101400@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20120120T140000 DTEND;TZID=/Q2S/Europe/Oslo:20120120T150000 SUMMARY:Q2S Colloquium: Social research methods for investigating Quality of Experience: a helicopter view - Katrien De Moor DESCRIPTION:In the first part of this talk, I will give a brief overview of social research methods that can used for investigating (the quality of) users experiences with technology and that could be useful as a complement to the standardized objective and subjective test methods. In addition, I will discuss a number of criteria that can assist in selecting the right method(s). In the second part of this talk, I will give a concrete example of a qualitative study on audiovisual content categorization. This study, which took place in the AURA lab, consisted of a series of structured interviews, aimed at eliciting attributes for categorizing audiovisual content. As part of the attribute elicitation procedure, 7 short audiovisual stimuli were shown to the test subjects. I will briefly discuss the set-up of the study, illustrate how qualitative data can be processed and share a number of preliminary results. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201201201400@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20120203T140000 DTEND;TZID=/Q2S/Europe/Oslo:20120203T150000 SUMMARY:Q2S Colloquium: Understanding n-way Network Traffic Flows - Nevil Brownlee DESCRIPTION:During the last decade, unsolicited one-way traffic has been used to study malicious activity on the Internet. Researchers usually observe such traffic in \'darkspace,\' i.e. into networks that have no active hosts. Nevil will present research work on traffic observed at the UC San Diego Network Telescope, using data covering January to June 2011. Nevil will also present some more recent work on one-way traffic reaching the U Auckland network; this is an active network with IPv6 as well as IPv4 traffic, and most of its traffic is two-way. Filtering out the two-way traffic has required careful study of how its flows behave, yielding some unexpected results. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201202031400@q2s.ntnu.no END:VEVENT BEGIN:VEVENT DTSTART;TZID=/Q2S/Europe/Oslo:20120316T131500 DTEND;TZID=/Q2S/Europe/Oslo:20120316T141500 SUMMARY:Q2S Colloquium: Modeling and Analysis of a P2P-VoD System Based on Stochastic Network Calculus - Kai Wang DESCRIPTION:Peer-to-peer video-on-demand (P2P-VoD) is one of the most commercially important and technically challenging applications. In such systems, each video file is typically divided into sub-pieces that are stored possibly at different sending peers, and the receiving peer often needs to coordinate multiple senders by specifying a transmission schedule for them. In this paper, we investigate this transmission scheduling problem for a specific P2P-VoD system which is PPLive. We formalize the problem of scheduling sub-piece transmission based on stochastic network calculus, and analyze its delay performance. Based on the delay analysis, an optimization problem is formulated to design the schedule for sending peers to transmit their sub-pieces. The objective of this optimization is to maximize a defined reward and at the same time meet the delay constraint required to ensure video quality at the receiver. URL:http://www.q2s.ntnu.no/q2s_colloquium/ LOCATION:E-258 (Q2S lunch room) ORGANIZER;CN="Q2S Colloquium administrator":MAILTO:q2sfc@q2s.ntnu.no UID:201203161315@q2s.ntnu.no END:VEVENT END:VCALENDAR