TCP流的带宽公平性保证机制研究

端到端的TCP拥塞控制机制使得TCP连接获得的瓶颈带宽反比于RTT。为了缓解TCP对于RTT较小流的偏向，区分服务的流量调节机制在RTT较小的流取得目标速率且获得多余资源的情况下可以确保RTT较大流不至于饥饿。现有的方法在网络拥塞程度较重或者RTT差异较大时不能有效地工作，因此提出了一种改进方法。其主要思想就是根据网络的拥塞程度自适应地调整对RTT较大流的保护程度。大量的仿真试验表明，所提的机制能有效保障TCP流的带宽公平性并且比现有方法具有更好的性能。     

Cisco SRP环上的带宽分配

给出了一种较简单的SRP(spatial reuse protocol)加权公平性算法的实现,并在此基础上提出了在Cisco SRP环上进行带宽定量分配的方案.在OPNET仿真环境下对这种带宽分配方案的效果进行了仿真和分析.仿真结果表明这种带宽分配方案具有良好的精确度.     

Shape optimization of curves and surfaces considering fairness metrics and elastic stiffness

A method is presented for generating round curves and surfaces allowing discontinuities in tangent vectors and curvatures. The distance of the centre of curvature from the specified point is used for formulating the objective function which is a continuous function of the design variables through convex and concave shapes. It is shown that a shell with and without ribs can be generated within the same problem formulation if the minimization problem is converted into a maximization problem and the parameter region where integration is to be carried out is restricted in view of the curvature. Optimal shapes are also found under constraints on the compliance against static loads. A multiobjective optimization problem is solved by the constraint method to generate a trade-off design between roundness and mechanical performance.An erratum to this article can be found at     

市场经济条件下的“公平与效率”

“公平与效率”的问题是经济学中一对难以解决的矛盾，也是社会主义市场经济中面临的难题，在生产力水平较低的社会主义初级阶段，要提高生产效率，必须调动私人投资的积极性，承认资金和劳动的个人所有，必须同时采取按劳分配及按资分配等多种分配方式，在这种条件下，收入分配的绝对公平是难以实现的，从行为科学的角度出发，通过各种具体措施，提高人们“心理的公平”度，可以促进社会主义市场经济效率的提高。     

谈二沙岛中心绿地的公平与效率

从多方面分析广州二沙岛中心绿地因性质转换而带来的公平与效率的思考。在中国社会的转型阶段,政府的角色也应有所转变。在处理公共利益与私人财产的矛盾时,应遵循合理公平的程序维护各方利益,并力取共赢局面。唯有如此,社会才能公正、稳定、持续地发展。     

一种兼顾效率和公平的分组标记算法

标记器位于网络边缘,根据应用和网络之间的服务约定为分组打上对应于不同丢弃优先级的标记。分组标记算法不仅应保证不同流共享资源的公平性,同时应兼顾资源的有效利用率。本文在分析现有分组标记算法的基础上,提出了一种兼顾效率和公平的分组标记算法,并通过仿真实验进行了验证。     

Packet video transport in ATM networks with single-bit feedback

The promise of a broadband integrated service digital network has led to the design of mechanisms for efficient transport of real-time compressed video in packet switching networks. We examine feedback control for video transport in ATM networks where the available feedback is a single bit of information carried in the cell header. We investigate the performance of three single-bit schemes for source rate adaptation. Two were originally for congestion control of bursty data traffic and are modified to control video traffic. The third scheme conveys more information about the state of queue(s) at the bottleneck. The simulation results show that all three schemes for feedback control of VBR video streams work remarkably well. During severe network congestion, the signal quality degrades gracefully, but not uniformly across all connections. Based on insights from the initial simulations, we propose a scheme to improve the fairness of service and demonstrate its effectiveness.     

Network Assisted Power Control for Wireless Data

The cellular telephone success story prompts the wireless communications community to turn its attention to other information services, many of them in the category of wireless data communications. One lesson of cellular telephone network operation is that effective power control is essential to promote system quality and efficiency. In recent we have applied microeconomic theories to power control taking into account notions of utility and pricing. Our earlier work has shown that this new approach to power control for wireless data performs better than traditional techniques applied for voice signals. However, the operating points of such a strategy result in an unfair equilibrium in that users operate with unequal signal-to-interference ratios. Further, the power control algorithms required to achieve such operating points are more complex than the simple signal-to-interference ratio balancing algorithms for voice. In this paper, we introduce a new concept, Network Assisted Power Control (NAPC) that maximizes utilities for users while maintaining equal signal-to-interference ratios for all users. The power control algorithm is easily implemented via signal-to-interference ratio balancing with the assistance of the network that broadcasts the common signal-to-interference ratio target.     

分组交换网络调度算法——SFQ+的研究

分组调度是实现计算机网络QoS保证的核心问题。该文描述了SFQ+分组调度算法，在SFQ算法的基础上引入了DWCS的动态窗函数约束机制，并与传统的SFQ和DWCS算法作了比较，给出了算法的性能评价，对算法的扩展进行了展望。