17038094
On-line Algorithm for Server Selection of Video Streaming over P2P Networks
Abstract We consider a video streaming application over P2Pnetworks and introduce the P2P on-line server selection problem. This task is related to the classic K-server problem, known from the theory of online algorithms. The difference is that our problem has a dynamic cost matrix, due to network congestion which may trigger the rerouting of streaming paths. With the assumption that the number of hops of any alternative path from the server node p to the requesting node q is at most δ times the number of hops of the shortest path from p to q, our dynamic work function algorithm works for the P2P on-line server selection problem with competitive ratio δ×(2k-1). 1. Introduction In this paper we consider a video streaming application over P2Pnetworks. As we know, it isdifficult to provide large scale streaming service using traditional, centralized client-serverarchitecture, since a bottleneck occurs at the server. The network service model known as Peer-to-Peer (P2P) solves this problem, due to its distributed nature. We address the issue of optimizing the server selection for video streaming in P2P networks.Optimization tasks are classified into online and offline problems. Optimization problems in which the input is received piece by piece and the corresponding piece of output must be produced before knowing the entire input are called online problems. In some optimization tasks, such as job scheduling, both the online and offline versions of the problem are meaningful. Many other situations, such as telephone circuit switching, investment planning etc. are intrinsically online. For these problems, offline algorithms are not acceptable. Competitive algorithms were introduced by Sleator and Tarjan [1] in the context of optimization problems. They sought a worst case complexity measure for on-line algorithms that have to make decisions based on current and previous parts of the input. In the on-line problem the input is given as a sequence σ = σ
2177063
A New Lightweight and Scalable Encryption Algorithm for Streaming Video over Wireless Networks
A process for improving the stability of a cadmium chalcogenide/copper chalcogenide photovoltaic cell is disclosed. The improvement comprises positioning a layer of a polymer composition containing electrically conductive particles between the copper chalcogenide layer and the metal electrode such that the metal electrode does not make physical contact with the copper chalcogenide layer.
10659233
Wiener indices of balanced binary trees
We study a new family of trees for computation of the Wiener indices. We introduce general tree transformations and derive formulas for computing the Wiener indices when a tree is modified. We present several algorithms to explore the Wiener indices of our family of trees. The experiments support new conjectures about the Wiener indices.
59897458
Algorithms and qos of video streaming over wireless networks
Video streaming over wireless networks has attracted much attention recently. It is well known that video streaming is QoS Stringent applications and wireless link suffers from erroneous and time-variant conditions. Significant research work has been conducted on QoS guarantee of video streaming application in Physical, MAC and Network layers. In this dissertation, the author designed a combination of packet ordering algorithm and transmission scheme for streaming video over a single wireless link and a distributed system for streaming video over multi-hop wireless networks, respectively. 
QoS routing has been widely researched and a number of routing protocols have been proposed to support routing of QoS stringent real-time applications. Recently, scalable video coding has been used for adaptation of video streaming to heterogeneous networks, especially wireless networks. The author proposed the routing criteria and routing algorithms for the routing of base layer (BL) and enhancement layer (EL) of MPEG-4 FGS. 
Research on Mobile Ad Hoc networks (MANETS) has been driven by either large scale military applications or specialized civilian applications which are tailored to very specialized missions and cost is typically not a main issue. Wireless mesh networks (WMN) meet the demand of a limited number of people wanting to form an ad hoc network for sharing information. In wireless mesh networks, Peer-to-Peer (P2P) video streaming service request generally can be satisfied by more than one video server. WMN P2P video streaming service can be modeled by K-server problem. Competitive work function algorithm is running in the distributed manner and is robust to the update message loss. Modified work function algorithm is proposed for P2P video streaming service over congested WMN. And the author conjectured that the modified work function algorithm is still competitive.
6971305
Video streaming over multi-hop wireless networks
In this paper, we considered the problem of transporting layered video over erroneous multi-hop wireless networks and proposed a distributed system. Our proposed distributed scheme is comprised of distributed control (DC), distributed buffer (DB) and distributed error control schemes. The DC scheme improves the efficiency of the network bandwidth usage and reduces the end-to-end delay of the streaming application. End-to-end delay jitter can be reduced by proper use of the DB nodes' buffer. Replacing the traditional EEC and ARQ with our distributed FEC and ARQ scheme reduces the error-protection overhead and ARQ delay and improves the wireless channel throughput. A layered video module is developed in GlomoSim 2.03 for video streaming application. We simulated our distributed scheme employing the layered video module in GlomoSim 2.03. Our simulation results confirm that QoS of streaming video over erroneous multi-hop wireless network can be improved using our proposed distributed scheme.
9126668
Hand Gesture Tracking for Wearable Computing Systems
A spin stabilized, earth orbitting satellite having a phased array antenna capable of radiating a plurality of steered electromagnetic beams to predetermined earth locations. The antenna array extends around the satellite and is made up of individual elements which are energized through semiconductor diode devices by electron beams. The electron beams are controlled by fields having the same frequency as the spin frequency of the satellite.
48875713
Reflections on Kurt Gödel
Newton/Descartes. Einstein/Gdel. The seventeenth century had its scientific and philosophical geniuses. Why shouldn't ours have them as well? Kurt Gdel was indisputably one of the greatest thinkers of our time, and in this first extended treatment of his life and work, Hao Wang, who was in close contact with Gdel in his last years, brings out the full subtlety of Gdel's ideas and their connection with grand themes in the history of mathematics and philosophy.The subjects he covers include the completeness of elementary logic, the limits of formalization, the problem of evidence, the concept of set, the philosophy of mathematics, time, and relativity theory, metaphysics and religion, as well as general ideas on philosophy as a worldview. Wang, whose reflections on his colleague also serve to clarify his own philosophical thoughts, distinguishes his ideas from those of Gdel's and on points of agreement develops Gdel's views further.The book provides a generous array of information on and interpretation of the two main phases of Gdel's career - the years between 1924 and 1939 at the University of Vienna, which were marked by intense mathematical creativity, and the period from 1940 to his death in 1978, during which he was affiliated with the Institute for Advanced Studies in Princeton, a time in which Gdel's interests steadily shifted from questions of logic to metaphysics. And it also examines Gdel's relations with the Vienna Circle, his philosophical differences with Carnap and Wittgenstein, the intimate and mutually fruitful friendship with Einstein, and the periodic bouts of depression for which Gdel was hospitalized a number of times over the course of his life.Hao Wang is Professor of Logic at The Rockefeller University and author of scores of articles and several books on logic, computers, and philosophy, including From Mathematics to Philosophy (extensively discussed with Gdel and containing contributions by him) and Beyond Analytic Philosophy: Doing Justice to What We Know (MIT Press Bradford Books). He is currently preparing a companion volume, Conversations with Kurt Gdel which will concentrate on Gdel's unpublished ideas. A Bradford Book.
10477328
Efficient Multiple-Link Adaptive Bandwidth Provisioning for End-to-End Quality of Service Guarantee
Future IP networks need to support different quality of service (QoS) sensitive services with distinct end-to-end QoS requirement. An attractive solution is to use adaptive bandwidth provisioning to provide guaranteed distinctive QoS and maintain high network efficiency at the same time. But, previous research on adaptive provisioning assumes dedicated bandwidth and is limited to the single-link case. This paper studies adaptive bandwidth provisioning to provide guaranteed statistical end-to-end QoS. The novelty of this study is that our adaptive bandwidth provisioning is performed on multiple links along the end-to-end path to satisfy the end-to-end statistical QoS requirement, and it is done in bandwidth sharing generalized processor sharing (GPS) networks, in which the received QoS of one flow can be interfered by other competing flows. The analysis and simulation results show that by utilizing adaptive bandwidth provisioning, guaranteed end-to-end statistical QoS can be achieved, and between the two possible schemes to carry out this multiple-link adaptive bandwidth provisioning, the end-to-end bandwidth provisioning scheme is more efficient than performing local adaptive bandwidth provisioning on each individual link
3839837
Creating Vulnerability Signatures Using Weakest Preconditions
Signature-based tools such as network intrusion detection systems are widely used to protect critical systems. Automatic signature generation techniques are needed to enable these tools due to the speed at which new vulnerabilities are discovered. In particular, we need automatic techniques which generate sound signatures - signatures which will not mistakenly block legitimate traffic or raise false alarms. In addition, we need signatures to have few false negatives and will catch many different exploit variants. We investigate new techniques for automatically generating sound vulnerability signatures with fewer false negatives than previous research using program binary analysis. The key problem to reducing false negatives is to consider as many as possible different program paths an exploit may take. Previous work considered each possible program path an exploit may take separately, thus generating signatures that are exponential in the size of the number of branches considered. In the exact same scenario, we show how to reduce the overall signature size and the generation time from exponential to polynomial. We do this without requiring any additional assumptions, or relaxing any properties. This efficiency gain allows us to consider many more program paths, which results in reducing the false negatives of generated signatures. We achieve these results by creating algorithms for generating vulnerability signatures that are based on computing weakest preconditions (WP). The weakest precondition for a program path to a vulnerability is a function which matches all exploits that may exploit the vulnerability along that path. We have implemented our techniques and generated signatures for several binary programs. Our results demonstrate that our WP-based algorithm generates more succinct signatures than previous approaches which were based on forward symbolic execution.
4409694
On route selection for interdomain traffic engineering
In this article we investigate a model of route selection for interdomain traffic engineering where routing to multiple destinations can be coordinated. We identify potential routing instability and inefficiency problems, and derive a set of practical guidelines to guarantee stability without global coordination. Using a realistic Internet topology, we show that route oscillations can happen even when a small number of ASes coordinate route selection for just a small number of destinations if the coordination does not follow our guidelines. Wc further extend our model so that ASes can adopt any route selection algorithms in a class of algorithms we call rational route selection algorithms; and the local ranking of routes of an AS can depend on ingress traffic patterns. We show that persistent route oscillations can happen in certain network settings even if the ASes strictly follow the constraints imposed by business considerations, and adopt any rational route selection algorithms.