14004456
Enhancing multimedia streaming performance through peer-paired collaboration
In this paper, a novel multimedia streaming framework called peer-paired pyramid streaming (P/sup 3/S) is proposed. The philosophy of P/sup 3/S is to enable collaboration between clients so as to bring in better performance. The structure of P/sup 3/S is basically a hybrid client/server and peer-to-peer structure and exhibits a triangle-cell based hierarchy. Based on P/sup 3/S, performance enhancement techniques are designed to increase the aggregated bandwidth of all participants. We present an optimal data allocation algorithm, which maximizes the overall throughput of the whole streaming session. We also present a greedy data allocation algorithm that is slightly suboptimal but much simpler. Extensive simulations were performed to demonstrate the effectiveness of proposed techniques.
16268564
FreeRank: implementing independent ranking service for multiplayer online games
Ranking is necessary for multiplayer online games to provide players with self-complacence and reference for choosing game counterparts. Most existing ranking solutions are tightly coupled with game applications of client-server architectures. In this paper, a novel scheme named FreeRank is proposed as a ranking service independent to specific architecture and detailed implementation of each individual game application. Based on a certificate-based framework and a reputation-based score-computing algorithm. FreeRank resolves the challenge of cheating prevention. Preliminary analysis and simulation results show that FreeRank is feasible and effective.
39099940
Efficient error recovery techniques in a novel multimedia streaming framework with peer-paired collaboration
Recently, active research has gone to application-level multicast that tries to bring all the merits of unicast and IP multicast together while avoiding their drawbacks. How to efficiently recover from errors in such a system is a difficult question yet to be answered. The current research focus is primarily on developing local error recovery techniques, but these techniques would not work in case of shared losses, which often occur in application-level multicast. In this paper, a novel multimedia streaming framework called peer-paired pyramid streaming (P/sup 3/S) is proposed. It is basically a hybrid client/server and peer-to-peer structure. In P/sup 3/S, clients are hierarchically organized and those at the same level are coupled and peer-pairs are then formed. Based on P/sup 3/S, we introduce some controlled delay between packets that are vulnerable to shared losses to combat with the shared losses. The proposed technique is supported by both theoretical and experimental results presented in this paper.
15663663
Kernel based articulated object tracking with scale adaptation and model update
Kernel based object tracking (KBOT) is one of the most popular and effective techniques for tracking task. However the constancy of the target model and unsound scale adaptation method are two main limitations. In this paper, we present a kernel based approach incorporated with scale estimation and target model update for articulated object tracking task. After predicating the object center with scale fixed KBOT, we extend scale selection theory to estimate the local optimal object scale. Once the object scale has been estimated, a kernel density estimation based strategy is developed to update the target model. Experimental results show that our approach is superior to traditional KBOT in the following two aspects: 1) it is less affected by the object scale change; 2) it is less prone to appearance variation.
1622406
Structure Analysis and SNR-Variance Evolution for Parallel Concatenated Coded IDMA Systems
This paper is concerned with parallel concatenated coded interleave-division multiple-access (IDMA) systems. We briefly present the transmitter/receiver structure of these systems and propose an efficient SNR-variance evolution scheme for bit-error-rate (BER) performance evaluation. The proposed evolution scheme is also useful for system performance optimization. Numerical results show that the BER performance curves obtained by simulation and evolution are quite close when the data length is long enough.
37867207
A Low-Latency Peer-to-Peer Approach for Massively Multiplayer Games
This paper focuses on the latency reduction problem in massively multiplayer games (MMGs). As the client-server (CS) architecture in use today in most commercial MMGs applications are exposing its weakness in scalability as the number of players increases, researchers start to consider the peer-to-peer (P2P) model that has inherent high scalability for MMGs. However, existing P2P models generally lead to high latency that significantly detracts from the playing experience. To improve this, we present a novel communication model intended to reduce the latency of network communication on game states. The model, based on DHT protocol, can select the best candidate node to perform server's role for a game zone. In contrast, existing P2P models designate 'peer servers' randomly without considering latency effects. The simulation shows that our approach obtains much lower latency than existing P2P models. The performance of our approach is shown to be even better than that of CS models.
6501389
A Hierarchical Queueing Model for Streaming Video over Multi-Hop Wireless Networks
In our previous work, we proposed a distributed buffer (DB) scheme to tackle the problem of transporting layered video over erroneous multi-hop wireless networks. In DB scheme, some intermediate nodes are selected as DB nodes, which are used to pre-buffer video packets before the video streaming starts. In this paper, a novel hierarchical queueing model for DB nodes is proposed. The video playback quality including buffer overflow probability and video quality throughput can be computed based on the proposed queueing model. The simulation result matches the queueing performance of video streaming application.
38177882
A Hybrid Feature Selection Approach for Microarray Gene Expression Data
Due to the huge number of genes and comparatively small number of samples from microarray gene expression data, accurate classification of diseases becomes challenging. Feature selection techniques can improve the classification accuracy by removing irrelevant and redundant genes. However, the performance of different feature selection algorithms based on different theoretic arguments varies even when they are applied to the same data set. In this paper, we propose a hybrid approach to combine useful outcomes from different feature selection methods through a genetic algorithm. The experimental results demonstrate that our approach can achieve better classification accuracy with a smaller gene subset than each individual feature selection algorithm does.
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.
5067889
Facial Expression Synthesis and Recognition with Intensity Alignment
A method of cooling section steel, particularly sectional steel girders, from rolling heat, wherein, prior to a final air cooling, a water cooling process is carried out in such a way that section steel portions with material concentrations are cooled at outwardly projecting portions of the steel sections over a width of application and a duration of application which are variable and subject to a predetermined cooling strategy supported by a process computer to a value which is at least still slightly above the transformation temperature Ar1.
29402189
Non-Standard Models for Formal Logics
showed that there must be a model in which that portion of the model which is supposed to represent the positive integers of the formal logic is not in fact isomorphic to the positive integers; indeed it is not even well ordered by what is supposed to be the relation of <. For the purposes of the present paper, we do not need a precise definition of what is meant by a standard model of a formal logic. The non-standard models which we shall discuss will be flagrantly non-standard, as for instance a model of the sort whose existence is proved by Henkin. It will suffice if we and our readers are in agreement that a model of a formal logic is not a standard model if either: (a) The relation in the model which represents the equality relation in the formal logic is not the equality relation for objects of the model. (b) That portion of the model which is supposed to represent the positive integers of the formal logic is not well ordered by the relation <. (c) That portion of the model which is supposed to represent the ordinal numbers of the formal logic is not well ordered by the relation <. Our first result is that there is no standard model for the system known as "Quine's New Foundations" (see [2] and [3]). This is proved for the logic originally proposed by Quine (see [2]), which is a system of such apparent weakness that so far no one has succeeded in proving the axiom of infinity in the system. Clearly, if there is no standard model for this apparently weak system, there cannot be a standard model for any apparently stronger system which one might form by adding additional axioms, such as the axiom of infinity. A natural reaction to this result would be to suspect that there is no model of any sort for Quine's New Foundations; that is to suspect that it is inconsistent. An alternative (and much less likely) reaction would be to suspect that the property of not having a standard model is perhaps a not uncommon property of strong formal logics, and to suspect that perhaps several of the familiar strong formal logics have no standard model. Unlikely as this might appear at first sight, we will present considerable evidence in favor of the idea. In particular we shall show that it is a property of each of the familiar formal logics that if it is w-consistent then one cannot prove in the logic itself that if the logic is consistent it must have a standard model; in fact, one cannot prove this statement about the logic even in certain stronger logics if these stronger logics are simply consistent.