Flow Control Strategy for the High Speed Network Based on Control Theory

Design of an effective congestion control scheme is a hot topic in the development of computer network. The flow control scheme can adjust the packet sending rate in source host, thus effectively avoiding the network congestion. This paper proposes a new flow control scheme based on discrete control theory. The simulation results show that this method can adjust the sending rate and queue level in buffer rapidly and effectively. The method is easy to implement and applicable to high speed networks.     

Civil aircraft fault tolerant attitude tracking based on extended state observers and nonlinear dynamic inversion

For the problem of sensor faults and actuator faults in aircraft attitude control,this paper proposes a fault tolerant control(FTC)scheme based on extended state observer(ESO)and nonlinear dynamic inversion(NDI).First,two ESOs are designed to estimate sensor faults and actuator faults respectively.Second,the angular rate signal is reconstructed according to the estimation of sensor faults.Third,in angular rate loop,NDI is designed based on reconstruction of angular rate signals and estimation of actuator faults.The FTC scheme proposed in this paper is testified through numerical simulations.The results show that it is feasible and has good fault tolerant ability.     

The Structure Entropy of Social Networks

Micro triadic structure is an important motif and serves the building block of complex networks. In this paper, the authors define structure entropy for a social network and explain this concept by using the coded triads proposed by Davis and Leinhardt in 1972. The proposed structure entropy serves as a new macro-evolution index to measure the network’s stability at a given timestamp.Empirical analysis of real-world network structure entropy discloses rich information on the mechanism that yield...     

A performance evaluation index system for multimedia communication networks and forecasting for web-based network traffic

This paper presents a new index system for the performance evaluation and network planning of multimedia communication systems using measurement on actual systems to support several different traffic types. In this index system, we develop an expert system to evaluate the performance of such multimedia communication networks including channel utilization and call blocking probability and packet delay, and apply the network planning methods to optimize the networks and forecast the demand of the growing multimedia communications systems. Two important planning problems for the multimedia communication systems are presented: optimization problem for construction of the world system and forecast problem for increasing traffic demands. We first discuss analysis methods, performance measures for the multimedia communication systems. Then, we describe network planning methods for the multimedia communication systems and give some efficiency network planning methods. Finally, we present some results studied in     

RKP based secure tracking in wireless sensor networks

To enhancing the wireless sensor network＇s security in target tracking and locating application, this article proposes a tracking cluster based mobile cluster distributed group rekeying protocol （MCDGR）. Based on the given sensitivity, sensors can locate the moving object in the monitored area and form a tracking cluster around it. This tracking cluster can follow the target logically, process data on the target and report to the sink node, and thus achieve the tracking function. We introduce a multi-path reinforcement scheme, q-composition scheme and one-way cryptographic hash function based random key predistribution algorithm （RKP）, which can guarantee a high accuracy and security and a low energy consumption on the same time in large-scale sensor networks.     

Internet end-to-end delay dynamics

1 .INTRODUCTIONEnd-to-end delay is one of the most i mportantcharacteristics of Internet end-to-end packet dy-namics , which may be applied to QoS manage-ment , SLA management , etc . A better compre-hension of end-to-end delay dynamics can help tosuggest efficient congestion control algorithm andadmission control scheme in which the parametersselection and technical principle can harmonizewith network behaviors . Much work has been doneto end-to-end delay dynamics and various modelshav…     

Self-configuring scheduling scheme for IPv6 traffic with multiple QoS classes

This paper proposes a new queuing model and adaptive scheduling scheme which realizes multi-class QoS mechanism under DiffServ architecture. The queuing model is composed of two parallel output subqueues, each output sub-queue adopts random drop algorithm by setting different buffer threshold for different class traffic, so it can provide multi-class QoS. The new proposed scheduling scheme which adaptively changes the parameter A can guarantee the performance target of high class traffic, in the mean time, improve the QoS of low classes traffic.     

Finite-time tracking control for motor servo systems with unknown dead-zones

A finite-time tracking control scheme is proposed in this paper based on the terminal slid- ing mode principle for motor servo systems with unknown nonlinear dead-zone inputs. By using the differential mean value theorem, the dead-zone is represented as a time-varying system and thus the inverse compensation approach is avoided. Then, an indirect terminal sliding mode control （ITSMC） is developed to guarantee the finite-time convergence of the tracking error and to overcome the singu- larity problem in the traditional terminal sliding mode control. In the proposed controller design, the unknown nonlinearity of the system is approximated by a simple sigmoid neural network, and the ap- proximation error is diminished by employing a robust term. Comparative experiments on a turntable servo system are conducted to show the superior performance of the proposed method.     

Designing cost-effective network-on-chip by dual-channel access mechanism

A dual-channel access mechanism to overcome the drawback of traditional single-channel access mechanism for network-on-chip (NoC) is proposed.In traditional single-channel access mechanism,every Internet protocol (IP) has only one channel to access the on-chip network.When the network is relatively idle,the injection rate is too small to make good use of the network resource.When the network is relatively busy,the ejection rate is so small that the packets in the network cannot leave immediately,and thus the probability of congestion is increased.In the dual-channel access mechanism,the injection rate of IP and the ejection rate of the network are increased by using two optional channels in network interface (NI) and local port of routers.Therefore,the communication performance is improved.Experimental results show that compared with traditional single-channel access mechanism,the proposed scheme greatly increases the throughput and cuts down the average latency with reasonable area increase.     

Game-theoretic approach to power and admission control in hierarchical wireless sensor networks

Power efficiency and link reliability are of great importance in hierarchical wireless sensor networks (HWSNs),especially at the key level,which consists of sensor nodes located only one hop away from the sink node called OHS.The power and admission control problem in HWSNs is comsidered to improve its power efficiency and link reliability.This problem is modeled as a non-cooperative game in which the active OHSs are considered as players.By applying a double-pricing scheme in the definition of OHSs’ utility function,a Nash Equilibrium solution with network properties is derived.Besides,a distributed algorithm is also proposed to show the dynamic processes to achieve Nash Equilibrium.Finally,the simulation results demonstrate the effectiveness of the proposed algorithm.     

多媒体传感器网络中服务感知的业务调度算法

作为传感器网络的高级形式，多媒体传感器网络在环境监控、安全监控以及医疗保健等诸多应用领域发挥重要作用。首先介绍一种提供区分服务的分簇传感器网络体系结构，进而提出一种服务感知的业务调度策略，使用非抢占的优先扳排队模型保障两类服务对时延的要求，以提供满足监控应用需求的QoS。理论分析和仿真试验证明了方法的有效性。较之其它典型方法，方法更适用于可提供区分服务的多媒体传感器网络。     

Study on the Class-Based Admission Control Scheme for DiffServ in MPLS Networks

Differentiated services (DiffServ) and MPLS are two major building blocks for providing multi-class services over IP networks. In order to respond to the need for relatively simple, coarse methods of providing different levels of service for Internet traffic, to support various types of applications and specific business requirements, the MPLS network infrastructure and the DiffServ traffic model will work together. Meanwhile, in today's environment of multiple service networks, it is necessary for the node in the networks to perform the control mechanism to guarantee various QoS. In     

基于MPLS流量工程的QoS性能分析

多媒体业务和实时业务的出现要求网络能够提供QoS保证,MPLS为解决这一问题提供了基本的网络框架,而流量工程则是实现这一问题的有力工具。MPLS网络的显式路由机制是流量工程实施的保障,不但可以满足业务流的QoS约束条件,同时还可以优化网络的性能。研究了基于MPLS流量工程的QoS保证机制,并以传输控制协议(TCP)和报文协议(UDP)为业务模型,以吞吐量为性能指标,采用仿真的方法对使用MPLS流量工程情况下的QoS性能进行了分析。实验结果表明,通过在MPLS网络中实施流量工程技术,无论是面向业务流的性能还是面向资源的性能都会得到很好的保证,较传统的IP网络有了明显的提高。     

无线多跳网络中基于QoS的自适应拥塞控制方案

提出的无线多跳网络中基于服务质量(QoS:Quality of service)的自适应拥塞控制方案是从两个方面实现拥塞控制和QoS保证的.一方面,通过控制路由请求过程,为实时业务选择时延较短的路由,为非实时业务选择时延较长的路由来控制拥塞并保证QoS.另一方面,按照QoS等级减小邻居结点的转发业务来增加拥塞结点占用信道的概率,从而消除拥塞并保证QoS.该方案的特点在于综合考虑了拥塞控制和QoS保证,能在控制拥塞的过程中提高服务的QoS质量.论文建立了路由发现成功率、端到端时延和丢包率的性能分析模型,并对提出的方案进行了性能分析.性能分析和仿真结果表明我们提出的方案能够有效的控制拥塞,并保证实时业务的QoS.     

DiffServ中基于端到端测量的接纳控制

提出了一种新的区分服务(DiffServ)网络中端到端剩余带宽的估计方法,在此基础上建立了Diff-Serv网络的分布式接纳控制机制,通过引入端到端流量测量手段,动态估计网络中可用的带宽资源,从而对到达的流实施有效的接纳控制,提高网络的服务质量。网络仿真实验结果表明,该接纳控制机制在保证网络服务质量的同时能保证较高的网络带宽利用率。     

超密集网络中基于聚类的资源分配方案

超密集网络(ultra-dense network, UDN)中,毫微微基站(femto-cell base station, FBS)的密集和随机部署会导致严重的小区间干扰。为了减轻干扰、保障用户服务质量(quality of service, QoS),提出了一种UDN中基于聚类的资源分配方案。首先,设计了一种基于加权密度的改进K-means聚类算法,将FBS动态划分为不同的簇。然后,以最大化UDN系统吞吐量为目标提出了一种两阶段时频资源分配方案:第一阶段,每个聚类内使用贪婪算法执行时频资源块的分配;第二阶段,利用资源补偿分配算法分配剩余的资源块,在考虑用户公平性的同时保证用户QoS。仿真结果表明,本文提出的资源分配方案能够有效提升系统吞吐量,同时保证用户QoS和公平性。     

Proportional rate scheduling based on QoS in mobile WiMAX networks

A new scheduling scheme based on users’ quality of service (QoS) in mobile WiMAX networks is presented. The proposed scheme tracks each user’s average rate and adjusts the corresponding scheduling weight adaptively to result in: (a) each user’s average rate is proportional to the corresponding QoS level; (b) the constraints of the minimal and/or maximal rates required by QoS can be satisfied; (c) the utility function of system is maximal under the constraints (a) and (b). Theoretical analysis based on utility function and simulation results indicates the system throughput can be improved dramatically in the proposed scheme.     

基于正则信道求逆预编码的MIMO功率分配方案研究

提出一种多用户MIMO系统中基于正则信道求逆预编码并具有QoS保障的功率分配方案:结合信道状态信息和用户QoS需求,分析得出约束条件的可行性判断依据;利用连续几何规划算法将非凸优化问题近似为凸优化问题,并辅以内点法求解最优功率分配方案;最终综合得出一套基于滑动窗口机制的功率分配框架。仿真结果表明,与现有算法相比,该方案能在有效保障用户最小速率和时延需求的基础上,显著提高系统可达速率。     

综合服务通信系统资源控制建模与分析

基于QoS资源控制是保证网络综合应用服务质量的必要手段。深入讨论了基于QoS最优综合服务通信系统(ISCS)模型及其最优资源控制策略和评价方法。建立了ISCS最优动态资源控制系统模型。针对资源控制重要部件buffer，又提出了面向buffer资源控制策略，并取得了良好的模拟结果。     

蓝牙个人区域网络视频流传输建模与仿真研究

目前无线ad hoc网络发展的目标是支持多媒体数据的传输,基于ad hoc网络的视频流传输有着巨大的应用前景。但是无线传输介质的不稳定特性决定了其支持视频流传输存在较大的挑战。在分析蓝牙技术特点的基础上,对蓝牙无线ad hoc网络视频流传输进行建模。设计基于所提模型的网络视频流传输模拟实验架构。在不同码率和不同路径长度的模拟环境下测试解码视频流的质量,研究分析蓝牙视频流传输性能。