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Guofeng Zhao Minchang Yu Chuan Xu Hong Tang 《通讯和计算机》2014,(1):59-65
Generating web traffic is of great importance to analyze performance of new designed network, test new equipment, and verify new protocols, etc.. However, most existing traffic generation systems tend to simulate the overall characteristics of network traffic, while neglecting of the behavior of the individual users. Nevertheless, in principle, the emerged characteristics of overall traffic originate from the aggregation of individual users' access behavior. In this paper, we propose an innovative web traffic generating method based on user browsing behavior. Our method simulates the real users' accessing behavior, and visits the real web servers. Then, we design and develop a web traffic generating system. Because our system accesses the real websites, it can produce almost the real network traffic. The test results show that the traffic generated by our system has characteristics of burstiness and self-similarity, which are widely found and characterized in many real networks. In addition, our system can better reflect real user's web browsing behavior. 相似文献
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Olfa Dridi Saoussen Krichen Adel Guitouni 《International Transactions in Operational Research》2014,21(6):935-953
The assignment and scheduling problem is inherently multiobjective. It generally involves multiple conflicting objectives and large and highly complex search spaces. The problem allows the determination of an efficient allocation of a set of limited and shared resources to perform tasks, and an efficient arrangement scheme of a set of tasks over time, while fulfilling spatiotemporal constraints. The main objective is to minimize the project makespan as well as the total cost. Finding a good approximation set is the result of trade‐offs between diversity of solutions and convergence toward the Pareto‐optimal front. It is difficult to achieve such a balance with NP‐hard problems. In this respect, and in order to efficiently explore the search space, a hybrid bidirectional ant‐based approach is proposed in this paper, which is an improvement of a bi‐colony ant‐based approach. Its main characteristic is that it combines a solution construction developed for a more complicated problem with a Pareto‐guided local search engine. 相似文献
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Pareto特征值问题是定义在正卦限上一类锥约束问题,在许多领域有着深厚的背景。将讨论Pareto特征值的一些理论性质,包括给定矩阵Pareto特征值范围及个数上界。引进了一类新矩阵,讨论并给出它的部分理论性质,可直接计算其最大Pareto特征值。 相似文献
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在缺乏先验知识的前提下,提出了约束条件的一种满意度,按照遗传算法求解多目标问题的步骤,求出非劣解集;然后根据适应度大小选出最优解;最后算例证明了该算法的有效性和可行性。 相似文献
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目前的步态优化算法仅仅实现了对单一目标的优化,把双足机器人步态优化看做是多目标优化问题,构建了衡量稳定性、能量消耗、步行速度三个目标评价函数。考虑到直接对多个目标加权求和的方法不能很好地处理多目标问题,提出一种新的基于约束满足的多目标步态参数优化算法,其思想是把基于惩罚函数的SPEA2(strength Pareto evolutionary algorithm2 )应用到多目标双足机器人动态步态参数优化问题上,规划出了同时满足这三个目标的动态优化步态。通过仿真实验表明了算法的有效性。 相似文献
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企业在承担社会责任时由于存在"搭便车"问题,缺乏主动承担社会责任的动力,运用新制度经济学企业理论分析了其原因。而且,为了解决这一问题,设计了一种制度以激励企业能够积极主动地承担起社会责任,同时证明了在确定性环境和不确定性环境下这种制度的纳什均衡都可以实现帕累托最优。 相似文献
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In commercial networks, user nodes operating on batteries are assumed to be selfish to consume their resources (i.e., bandwidth and power) solely maximizing their own benefits (e.g., the received signal-to-noise ratios (SNRs) and datarates). In this paper, a cooperative game theoretical framework is proposed to jointly perform the bandwidth and power allocation for selfish cooperative relay networks. To ensure a fair and efficient resource sharing between two selfish user nodes, we assume that either node can act as a source as well as a potential relay for each other and either node is willing to seek cooperative relaying only if the datarate achieved through cooperation is not lower than that achieved through noncooperation (i.e., direct transmission) by consuming the same amount of bandwidth and power resource. Define the cooperative strategy of a node as the number of bandwidth and power that it is willing to contribute for relaying purpose. The two node joint bandwidth and power allocation (JBPA) problem can then be formulated as a cooperative game. Since the Nash bargaining solution (NBS) to the JBPA game (JBPAG) is computationally difficult to obtain, we divide it into two subgames, i.e., the bandwidth allocation game (BAG) and the power allocation game (PAG). We prove that both the subgames have unique NBS. And then the suboptimal NBS to the JBPAG can be achieved by solving the BAG and PAG sequentially. Simulation results show that the proposed cooperative game scheme is efficient in that the performance loss of the NBS result to that of the maximal overall data-rate scheme is small while the maximal-rate scheme is unfair. The simulation results also show that the NBS result is fair in that both nodes could experience better performance than they work independently and the degree of cooperation of a node only depends on how much contribution its partner can make to improve its own performance. 相似文献