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 计算机应用研究 , 2009, Abstract: In order to solve the problem of the cheat of malicious users in P2P electronic commerce, this paper presented a trust model of electronic commerce. The model used the structure of mixed P2P network with super nodes, made P2P network to some different domains and computed the trust degree respectively for the nodes in and between domains. The model consi-dered the amount and time of the trade and enhanced the veracity of the computing of the trust degree. Experimental results manifest that the model can decrease the malicious trade effectively.
 Mathematics , 2012, Abstract: The behavior of rational and selfish players (receivers) over a multiple-input multiple-output Gaussian broadcast channel is investigated using the framework of noncooperative game theory. In contrast to the game-theoretic model of the Gaussian multiple access channel where the set of feasible actions for each player is independent of other players' actions, the strategies of the players in the broadcast channel are mutually coupled, usually by a sum power or joint covariance constraint, and hence cannot be treated using traditional Nash equilibrium solution concepts. To characterize the strategic behavior of receivers connected to a single transmitter, this paper models the broadcast channel as a generalized Nash equilibrium problem with coupled constraints. The concept of normalized equilibrium (NoE) is used to characterize the equilibrium points and the existence and uniqueness of the NoE are proven for key scenarios.
 Computer Science , 2015, Abstract: This paper explores an old problem, {\em Byzantine fault-tolerant Broadcast} (BB), under a new model, {\em selective broadcast model}. The new model "interpolates" between the two traditional models in the literature. In particular, it allows fault-free nodes to exploit the benefits of a broadcast channel (a feature from reliable broadcast model) and allows faulty nodes to send mismatching messages to different neighbors (a feature from point-to-point model) simultaneously. The {\em selective broadcast} model is motivated by the potential for {\em directional} transmissions on a wireless channel. We provide a collection of results for a single-hop wireless network under the new model. First, we present an algorithm for {\em Multi-Valued} BB that is order-optimal in bit complexity. Then, we provide an algorithm that is designed to achieve BB efficiently in terms of message complexity. Third, we determine some lower bounds on both bit and message complexities of BB problems in the {\em selective broadcast model}. Finally, we present a conjecture on an "exact" lower bound on the bit complexity of BB under the {\em selective broadcast} model.
 Gautam Bharali Mathematics , 2010, Abstract: The Levi geometry at weakly pseudoconvex boundary points of domains in C^n, n \geq 3, is sufficiently complicated that there are no universal model domains with which to compare a general domain. Good models may be constructed by bumping outward a pseudoconvex, finite-type \Omega \subset C^3 in such a way that: i) pseudoconvexity is preserved, ii) the (locally) larger domain has a simpler defining function, and iii) the lowest possible orders of contact of the bumped domain with \bdy\Omega, at the site of the bumping, are realised. When \Omega \subset C^n, n\geq 3, it is, in general, hard to meet the last two requirements. Such well-controlled bumping is possible when \Omega is h-extendible/semiregular. We examine a family of domains in C^3 that is strictly larger than the family of h-extendible/semiregular domains and construct explicit models for these domains by bumping.
 Computer Science , 2015, Abstract: We present the first algorithm that implements an abstract MAC (absMAC) layer in the Signal-to-Interference-plus-Noise-Ratio (SINR) wireless network model. We first prove that efficient SINR implementations are not possible for the standard absMAC specification. We modify that specification to an "approximate" version that better suits the SINR model. We give an efficient algorithm to implement the modified specification, and use it to derive efficient algorithms for higher-level problems of global broadcast and consensus. In particular, we show that the absMAC progress property has no efficient implementation in terms of the SINR strong connectivity graph $G_{1-\epsilon}$, which contains edges between nodes of distance at most $(1-\epsilon)$ times the transmission range, where $\epsilon>0$ is a small constant that can be chosen by the user. This progress property bounds the time until a node is guaranteed to receive some message when at least one of its neighbors is transmitting. To overcome this limitation, we introduce the slightly weaker notion of approximate progress into the absMAC specification. We provide a fast implementation of the modified specification, based on decomposing a known algorithm into local and global parts. We analyze our algorithm in terms of local parameters such as node degrees, rather than global parameters such as the overall number of nodes. A key contribution is our demonstration that such a local analysis is possible even in the presence of global interference. Our absMAC algorithm leads to several new, efficient algorithms for solving higher-level problems in the SINR model. Namely, by combining our algorithm with known high-level algorithms, we obtain an improved algorithm for global single-message broadcast in the SINR model, and the first efficient algorithm for multi-message broadcast in that model.
 计算机科学 , 2008, Abstract: The existing P2P simulators have its disadvantages,and are not fit for many practical P2P applications.It is necessary to model each of the elements in the P2P networks and design a P2P simulator for the actual applications.In this paper,a simulation model which closely reflects the real P2P networks is designed.Based on the behavior of user in the P2P networks applications,the model has designed many attributes for every peer;some current strategies of peers selection and pieces selection are included in t...
 - , 2016, DOI: 10.6040/j.issn.1671-9352.3.2015.067 Abstract: 摘要： 针对已有的广播加密方案无法很好地对用户的隐私进行保护问题,提出了基于合数阶双线性群以及拉格朗日插值法的具有接收者匿名性的广播加密方案。并针对现有的P2P社交网络存在的隐私保护方面的不足,基于匿名广播加密方案构建了P2P社交网络隐私保护系统。在Android客户端设计与实现了关键算法及系统的功能模块,并对各模块进行了功能验证。验证结果表明该匿名广播加密算法在保证对用户数据进行分发同时,解决了已有P2P社交网络中依赖高代价匿名技术来对用户数据进行隐私保护或者用户权限的过度开放等问题,有效地保护了接收者的隐私性。Abstract: Aiming at the problem that the existing broadcast encryption scheme cannot protect the users privacy well, we proposed a broadcast encryption scheme with the receiver anonymity based on composite order bilinear groups and Lagrange interpolation method. And aiming at the low privacy protection in the existing P2P network system, we constructed a P2P network privacy protection system based on the proposed anonymous broadcast encryption scheme. Then,we designed and implemented function modules of the system by Android, and verified every modules function. The results show that the proposed anonymous broadcast encryption algorithm can distribute the users data and effectively protect the privacy of the receiver, at the same time, solve the problems that exist in the existing in P2P networks which rely on expensive anonymous technology to protect user data privacy and the excessive open of user permission
 计算机科学 , 2007, Abstract: Centralized P2P network model is not suitable for the large-scale network, while the pure distributed P2P network model is inefficient. According to the corresponding sociology principle, the layered and distributed P2P network model, named REC, is propos
 Computer Science , 2015, Abstract: We study a dynamic version of the Multiple-Message Broadcast problem, where packets are continuously injected in network nodes for dissemination throughout the network. Our performance metric is the ratio of the throughput of such protocol against the optimal one, for any sufficiently long period of time since startup. We present and analyze a dynamic Multiple-Message Broadcast protocol that works under an affectance model, which parameterizes the interference that other nodes introduce in the communication between a given pair of nodes. As an algorithmic tool, we develop an efficient algorithm to schedule a broadcast along a BFS tree under the affectance model. To provide a rigorous and accurate analysis, we define two novel network characteristics based on the network topology and the affectance function. The combination of these characteristics influence the performance of broadcasting with affectance (modulo a logarithmic function). We also carry out simulations of our protocol under affectance. To the best of our knowledge, this is the first dynamic Multiple-Message Broadcast protocol that provides throughput guarantees for continuous injection of messages and works under the affectance model.