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International Symposium on Parallel and Distributed Processing (IPDPS)

作者： Thomas Bocek Michael Shann David Hausheer Burkhard Stiller Communication Systems Group Department of Informatics IFI University of Zurich Switzerland Computer Engineering and Networks Laboratory ETH Zurich Switzerland

One of the key challenges in peer-to-peer networks is the design of incentives to encourage peers to share their resources. Incentives are necessary in order to exploit the full potential of these systems. The tit-for-tat incentive scheme, as used in BitTorrent for example, has proven to be a successful approach in P2P file sharing systems, where peers have direct relations and share the same kind of resources. However, in P2P systems where different kind of resources are shared between peers with non-direct relations, the design of incentives remains a challenge. In this paper, a large-scale, fully decentralized P2P collaboration network is shown, where peers share not only bandwidth and storage space, but also contribute by editing articles and voting for or against changes. A new incentive scheme is proposed which supports non-direct relations and provides incentives for sharing different kind of resources. The incentive scheme is based on a reputation system that assigns a reputation value to every peer reflecting its previous behavior in the network. Based on this value, the service level is differentiated, i.e. the higher a peer's reputation the better the quality of service it can get from the network. The service differentiation has been analyzed and simulated with rational, irrational and altruistic peers based on game theory concepts.

关键词： Game theory Large-scale systems Collaboration Incentive schemes Thin film transistors Peer to peer computing Voting Bandwidth Quality of service Analytical models

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Distributed and Optimal Congestion Control for Application-Layer Multicast: A Synchronous Dual Algorithm

Distributed and Optimal Congestion Control for Application-L...

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Consumer communications and Networking Conference, CCNC IEEE

作者： Jinyao Yan Martin May Bernhard Plattner Computer and Network Center Communication University of China Beijing China Computer Engineering and Networks Laboratory Swiss Federal Institute of Technology ETH Zurich Switzerland

In this paper, we study the topic of distributed and optimal congestion control for scalable video streams in application-layer multicast (ALM). We propose a TCP-friendly, fully distributed synchronous algorithm based on the utility-price model which maximizes the global utilities for the streams in the application-layer multicast tree. With the help of numerical study, we show that our proposed algorithm optimizes the overall video quality for fine-grained scalable streams, while minimizing the messaging overhead in the application-layer multicast channel.

关键词： Optimal control Multicast algorithms Streaming media Multicast protocols Unicast communication system control computer networks Distributed computing Distributed control Algorithm design and analysis

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Task scheduling and lightpath establishment in optical grids

Task scheduling and lightpath establishment in optical grids

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INFOCOM 2008: 27th IEEE communications Society Conference on computer communications

作者： Liu, Xin Wei, Wei Qiao, Chunming Wang, Ting Hu, Weisheng Guo, Wei Wu, Min-You Department of Computer Science and Engineering SUNY Buffalo NY 14260 United States NEC Laboratories America Princeton NJ 08540 United States State Key Lab. of Advanced Optical Communication Systems and Networks SJTU Shanghai 200030 China

ISBN: (纸本)9781424420261

Data-intensive Grid applications require huge data transferring between multiple geographically separated computing nodes where computing tasks are executed. For a future WDM network to efficiently support this type of emerging applications, traditional approaches to establishing lightpaths between given source destination pairs are not sufficient because a computing task may be executed on any one of several computing nodes having the necessary resources. Therefore, lightpath establishment has to be considered jointly with task scheduling to achieve best performance. In this paper, we study the optimization problems of jointly scheduling both computing resources and network resources. We first present the formulation of two optimization problems with the objectives being the minimization of the completion time of a job and minimization of the resource usage/cost to satisfy a job with a deadline respectively. When the objective is to minimize the completion time, we devise an optimal algorithm for a special type of applications. Furthermore, we propose efficient heuristics to deal with general applications with either optimization objective and demonstrate their good performances via simulation. © 2008 IEEE.

关键词： Optimization

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LiveShift: Peer-to-Peer Live Streaming with Distributed Time-Shifting

LiveShift: Peer-to-Peer Live Streaming with Distributed Time...

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International Conference on Peer-to-Peer Computing

作者： Fabio Victora Hecht Thomas Bocek Cristian Morariu David Hausheer Burkhard Stiller University of Zurich Institute of Informatics (IFI) Zurich Switzerland ETH Zurich Computer Engineering and Networks Lab (TIK) Zurich Switzerland

The increasing assortment of devices with IP connectivity contributes to the high popularity of video sharing over the Internet. High traffic generated by such applications at the source can be better distributed using a peer-to-peer overlay, since every user forwards information to other users. Current implementations target either live or on demand video streaming. LiveShift is an application that combines both approaches. While video is transmitted through the peer-to-peer network in a live fashion, all peers participate in a distributed storage. This adds ability to replay time-shifted streams from other peers in a distributed and scalable manner. For the demonstration, a decentralized network is used, with peers running on EMANICSlab nodes and notebook computers.

关键词： Streaming media Peer to peer computing Watches Media computers Graphical user interfaces Buffer storage

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Loss temporal dependency characteristic inference in wireless sensor network

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Journal of Computational Information Systems 2008年第5期4卷 2303-2308页

作者： Li, Yongjun Ji, Wenli Dai, Yafei Computer Networks and Distributed Systems Laboratory Peking University Beijing 100871 China School of Computer Science Northwestern Polytechnical University Xi'an 710072 China School of Communication Engineering Xi'an University of Science and Technology Xi'an 710075 China State Key Lab. for Adv. Opt. Commun Syst and Networks Beijing 1000871 China

The internal link loss characteristic inference has become an increasingly important issue for operating and evaluating a wireless sensor network. Due to the inherent stringent bandwidth and energy constraints, it is usually impractical to directly collect link loss statistical data from each node in sensor network. Here we consider the problem of inferring the internal link loss characteristics from end-to-end measurement. We use the Gilbert error model to model the sensor link losses, formulate the problem of link loss characteristics estimation as a Bayesian inference problem, and propose a Markov Chain Monte Carlo (MCMC) algorithm to solve it. The simulation shows that the link loss performance parameters can be inferred accurately, and the proposed algorithm scales well according to the sensor network size. © 2008 Binary Information Press.

关键词： Inference engines

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Loss cumulate generating function inference and application in wireless sensor network

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Journal of Computational Information Systems 2008年第4期4卷 1399-1407页

The internal link loss characteristic inference has become an increasingly important issue for operating and evaluating a wireless sensor network. Due to the inherent stringent bandwidth and energy constraints of sensors, it is usually impractical to directly monitor each node or link in wireless sensor network. We consider the problem of inferring the internal link loss characteristics from passive end-to-end measurement in this paper. Specifically, the link loss performance inference during the data aggregation is considered. Under the assumptions that the link losses are mutually independent, we elaborate a bias corrected link loss Cumulant Generating Function (CGF) algorithm. The simulation results show that the internal link loss CGF can be inferred accurately comparable to the sampled internal link loss CGF. At the end of this paper, we apply the result of internal link loss CGF inference to identify the lossy link in sensor network.

关键词： Sensor nodes

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Audio-Visual Speech Processing Framework for Lip Reading

Audio-Visual Speech Processing Framework for Lip Reading

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International Conference on Information and communication Technologies: From Theory to Applications, ICTTA

作者： Abdulbaset M. Nasr Abd Rahman Ramli Mohammad Hamiruce Shamala K Subramaniam Robotics Lab Institute of advanced technology Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Computer and Communications Systems Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Electrical and Electronics Engineering Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Communication Technology & Networks Faculty of Computer Science and Information Technology Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia

It is well known that speech production and perception process is inherently bimodal consisting of audio and visual components. Recently there has been increased interest in using the visual modality in combination with the acoustic modality for improved speech processing. This field of study has gained the title of audio-visual speech processing. Lip movement recognition, also known as lip reading, is a communication skill which involves the interpretation of lip movements in order to estimate some important parameters of the lips that include, but not limited to, size, shape and orientation. In this paper, we represent a hybrid framework for lip reading which is based on both audio and visual speech parameters extracted from a video stream of isolated spoken words. The proposed algorithm is self-tuned in the sense that it starts with an estimations of speech parameters based on visual lip features and then the coefficients of the algorithm are fine-tuned based on the extracted audio parameters. In the audio speech processing part, extracted audio features are used to generate a vector containing information of the speech phonemes. These information are used later to enhance the recognition and matching process. For lip feature extraction, we use a modified version of the method used by F. Huang and T. Chen for tracking of multiple faces. This method is based on statistical color modeling and the deformable template. The experiments based on the proposed framework showed interesting results in recognition of isolated words.

关键词： Speech processing Image processing Parameter estimation Data mining Feature extraction Robots computer networks Systems engineering and theory communications technology computer science

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Influence of different system abstractions on the performance analysis of distributed real-time systems

Influence of different system abstractions on the performanc...

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EMSOFT'07: 7th ACM and IEEE International Conference on Embedded Software

作者： Perathoner, Simon Wandeler, Ernesto Thiele, Lothar Hamann, Arne Schliecker, Simon Henia, Rafik Racu, Razvan Ernst, Rolf Harbour, Michael González Computer Engineering and Networks Laboratory ETH Zurich Switzerland Institute of Computer and Communication Network Engineering TU Braunschweig Germany Grupo de Computadores y Tiempo Real Universidad de Cantabria Santander Spain

ISBN: (纸本)9781595938251

System level performance analysis plays a fundamental role in the design process of real-time embedded systems. Several different approaches have been presented so far to address the problem of accurate performance analysis of distributed embedded systems in early design stages. The existing formal analysis methods are based on essentially different concepts of abstraction. However, the influence of these different models on the accuracy of the system analysis is widely unknown, as a direct comparison of performance analysis methods has not been considered so far. We define a set of benchmarks aimed at the evaluation of performance analysis techniques for distributed systems. We apply different analysis methods to the benchmarks and compare the results obtained in terms of accuracy and analysis times, highlighting the specific effects of the various abstractions. We also point out several pitfalls for the analysis accuracy of single approaches and investigate the reasons for pessimistic performance predictions. Copyright 2007 ACM.

关键词： Real time systems

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Wireless opportunistic podcasting: Implementation and design tradeoffs

Wireless opportunistic podcasting: Implementation and design...

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2007 International Conference on Mobile Computing and Networking, MobiCom'07 - 2nd ACM Workshop on Challenged networks, CHANTS'07

作者： May, Martin Lenders, Vincent Karlsson, Gunnar Wacha, Clemens Computer Engineering and Networks Laboratory ETH Zurich 8092 Zurich Switzerland Department of Electrical Engineering Princeton University Princeton NJ 08544 United States Laboratory for Communication Networks KTH Royal Inst. of Tech. 100 44 Stockholm Sweden

ISBN: (纸本)9781595937377

Podcasting has become a very popular and successful Internet service in a short time. This success illustrates the interest for participatory broadcasting, but podcasting is alas only available with fixed infrastructure support to retrieve publicized episodes. We aim at releasing this limitation and present herein a podcasting system architecture based on opportunistic wireless networking that allows us to extend podcasting to ad hoc domains. The design is explained and presented together with a prototype implementation running on hand-held devices. We analyze different fundamental design tradeoffs based on measurements. Copyright 2007 ACM.

关键词： Delay tolerant networks

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Rotation sensing based on a slow-light resonating structure with high group dispersion

Rotation sensing based on a slow-light resonating structure ...

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作者： Chao, Peng Zhengbin, Li Anshi, Xu Natl. Lab. on Local Fiber-Optic Communication Networks and Advanced Optical Communication Systems School of Electronics Engineering and Computer Science Peking University Peking 100871 China

The concept of the Sagnac effect in a slow-light medium and resonator structure with a high group dispersion is investigated. It is found that a slow-light medium can be utilized for relative motion sensing, and a slow-light resonator structure is suitable to detect absolute rotation for navigation purposes. It is noted that the high group dispersion leads to a huge enhancement of the rotation sensor's sensitivity in a resonating structure, and an approach to evaluate and design resonator devices with slow-light property is proposed. Moreover, a folded loop-lattice-based structure is numerically simulated to verify the concept. © 2007 Optical Society of America.

关键词： Resonators

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