基于等级域的多服务Agent协作求解问题研究

在合同网当中引入等级域的概念,建立相应的基于等级域的多服务Agent模型GF-CNM,并采用随机TOP-N算法对等级域中不同等级的各个服务Agent的等级跃迁进行了算法描述和分析。该模型能减少任务协作时引起的网络通信量,避免对不相关服务Agent求解的时间开销,并均衡协作任务的分布,在一定程度上避免了“忙者越忙,闲者越闲”的“马太效应”,有效地缓解了资源受限条件下的任务协作求解问题。     

一种电磁信号分析的Agent协作模型

基于KQML语言,通过合同网模型对战场电磁环境模拟系统中的电磁信号分析Agent进行改进,使电磁信号Agent间的协作能力提高,增强了电磁信号分析的准确性和实际应用能力。在此具体对传统合同网进行了改进,增加了公共黑板通信方式,对投标者进行了合理的筛选,并增加了n个投标者,通过信号管理Agent向其发送标书,从而选择合适的投标者,与传统合同网不同的是这里的中标者不惟一,符合标准的都可成为中标者。     

基于扩展合同网的多Agent协作研究

分析传统合同网方法的不足,提出改进和扩展合同网的方法.在改进的合同网方法基础上,研究了基于扩展合同网方法的多Agent协作策略,通过对招标和投标双方状态的扩充以及对投标者评价指标的引入,完善合同网方法的招投标过程,提高了合同网方法的招标效率以及用户任务的完成质量.     

基于MAS的分布式作战任务分配研究

首先介绍了基于MAS的任务分配概念,并通过分析传统合同网（CNP）模型的缺点,给出了基于改进合同网的任务分配模型,详细描述了改进合同网的任务协商过程;最后,结合典型军事仿真应用实例,对比分析了该模型相比于传统合同网模型的优点。     

面向可重构服务承载网的分域混合承载组调度研究

传统网络技术体系,网络是封闭的、刚性的,无法满足未来网络大量差异化业务的规模化应用,由此提出了面向服务提供的柔性网络技术体系,该体系将传统网络中的用户业务、网络服务和网络基础设施中的紧耦合关系转变为松耦合关系,通过资源分割构建可重构服务承载网实现对业务的服务质量保证。该文分析了服务承载网映射到交换结构的需求,提出分域调度的思想。通过选择关闭部分交叉节点的方法建立了crossbar交换结构分域模型,实现了分域调度的端口分离。提出了支持可重构服务承载网构建的混合承载组调度(HCGS)算法,推导了承载组内SDRR(Smoothed Deficit Round Robin)调度、单个域内基于时间戳的输入端口调度和交叉节点输出端口调度算法,证明了HCGS具有良好的时延性能和最坏公平指数(WFI)公平性。仿真结果表明:在均匀分布的泊松业务源条件下,分域HCGS算法具有更优的时延性能,可保证业务带宽的公平性。在diagonal非均匀允许流量条件下,该算法的吞吐量可达100%。     

一种价格时间Petri网的状态空间计算

价格时间Petri网是对web服务过程和工作流模型等进行时间和成本分析的一种新工具.而价格时间自动机则是一种相对成熟的工具.提出一种状态空间计算方法,可以将价格时间Petri网的状态空间构造为一个价格时间自动机.该方法的核心思想是在扩展状态类中增加价格参数.进一步证明了构造出的价格时间自动机和初始的价格时间Petri网是双相似的.     

基于蚁群优化的时间Petri网及其在柔性制造系统调度优化中的应用

Petri网的优化调度求解主要采用基于状态空间的智能搜索方法,执行效率往往不高.提出基于蚁群优化的时间Petri网,通过在Petri网的变迁和进化规则中引入蚁群优化机制,改变Petri网原有的非确定性选择行为,使之具备蚁群寻优选择智能行为,克服了需要基于状态空间进行启发式搜索的缺陷,提高了调度优化的计算效率.最后应用蚁群优化时间Petri网模型,对柔性制造系统的区间Job Shop调度问题进行建模和优化求解.实验结果进一步验证了所提模型和方法的有效性.     

云过程神经网络模型及算法研究

该文针对输入输出具有不确定性特征并与时间或过程有关的复杂非线性系统建模和求解问题,利用过程神经网络对时变信号的动态处理能力,结合云模型对定性定量概念的转化能力,构建了一种具有不确定性信息处理能力的云过程神经网络模型,并采用猫群优化算法同时对网络结构和参数进行并行优化设计,提高了网络逼近及泛化能力,实现了神经网络在时间域和不确定信息处理领域上的有效扩展。仿真实验结果验证了模型和算法的可行性和有效性。     

一种区分服务综合方案的模型与性能分析

本文提出了一种将Internet网络分组传输延时和丢失控制的区分服务要求相结合的综合方案,它具有较强的通用性和灵活性.文章给出了PHB实现机制的一种基于随机Petri网模型的分析框架,并给出了性能指标的分析和数值结果.模型求解采用了一种分解、迭代的近似方法,可以有效降低求解复杂度.近似分析结果和模拟结果的比较证明,这种近似求解方法是可行的.     

基于角色等级树的光网络信息多域云访问控制研究

为了提高光网络信息多域云访问和调度能力,提出基于角色等级树的光网络信息多域云访问控制方法。构建光网络信息多域云访的分布式存储结构模型,结合特征重建重组方法进行光网络信息多域云数据的结构重组,在高维特征空间中提取光网络信息多域云数据的关联规则性特征量,采用模糊相关性融合方法进行光网络信息多域云数据信息融合和特征调度,结合谱分析方法进行光网络信息多域云访问和信息检索,采用角色等级树进行光网络信息多域云访问过程中的分类控制,提高光网络信息多域云数据的访问和调度能力。仿真结果表明,采用该方法进行光网络信息多域云访问控制的特征分辨力较强,准确性较好,数据访问的查准性较好。     

A teletraffic model for the Physical Downlink Control Channel in LTE

Recent advances in mobile handsets have led to new trends in mobile broadband data consumption, with a huge increase of signaling traffic generated by always-connected devices. Thus, a proper planning of control channels in mobile networks is necessary to avoid network capacity problems and provide an appropriate quality of service to the end user. A key issue in network planning is the availability of a complete and accurate system model. In this paper, an analytical performance model for the Long Term Evolution (LTE) Physical Downlink Control Channel (PDCCH) is constructed based on queuing theory. Unlike previous works, the proposed model considers important network features, such as link adaptation, and can be tuned with available network performance statistics. Model assessment is carried out by comparing performance estimates with request-level simulations and real performance measurements taken from a live LTE network. Results show that the proposed model can predict the PDCCH load distribution in a live network accurately.     

Game of energy consumption balancing in heterogeneous sensor networks

In a multi‐hop sensor network, sensors largely rely on other nodes as a traffic relay to communicate with targets that are not reachable by one hop. Depending on the topology and position of nodes, some sensors receive more relaying traffic and lose their energy faster. Such imbalanced energy consumption may lead to server problems like network partitioning. In this paper, we study the problem of energy consumption balancing (ECB) in heterogeneous sensor networks by assuming general any‐to‐any traffic pattern. We consider both factors of transmission power and forwarding load in measuring energy consumption. To find a solution, we formulate the problem as a strategic network formation game with a new utility function. We show that this game is guaranteed to converge to strongly connected topologies which have better ECB and bounded inefficiency. We propose a localized algorithm in which every node knows only about its k‐hop neighbourhood. Through simulations on uniform and clustered networks with various densities, we show that the performance of our algorithm is comparable with global and centralized algorithms. Copyright © 2015 John Wiley & Sons, Ltd.     

Design and analysis of RT-Ring: a protocol for supporting real-time communications

Distributed applications with quality of service (QoS) requirements are more and more used in several areas (e.g., automated factory networks, embedded systems, conferencing systems). These applications produce a type of traffic with hard timing requirements, i.e., transmissions must be completed within specified deadlines. To handle these transmissions, the communication system must use real-time protocols to provide a communication service that is able to satisfy the QoS requirements of the distributed applications. In this paper, the authors propose a new real-time protocol, called RT-Ring, able to support transmissions of both real-time and generic traffic over a ring network. RT-Ring provides both network guarantees and high network resource utilization, while ensuring the compatibility with the emerging differentiated service architectures. Network guarantees are fully proved and high network utilization is highlighted by a comparative study with the FDDI protocol. This comparison shows that RT-Ring network capacities are greater than the corresponding FDDI capacities. In fact, by assuming the FDDI frames with a length equal to the RT-Ring slot size and by using the same traffic load the authors show that the capacities of FDDI are equal to the lower bound capacities of RT-Ring.     

GSM/TD-SCDMA网络话务分流网络参数优化解决方案

随着3G数据业务的暴涨,面对日益激增的用户流量,网络负载的迅速抬升,各地GSM 网络陆续亮起了红灯.特别是今年年初,部分地市GSM 网络的无线综合利用率接近90%,远超话务负荷的红色警戒线.与之对应,网络质量日益完善的TD-SCDMA 网络利用率持续偏低.为均衡两网话务,通过网络GSM/3G 互操作参数调整、网络控制的...     

Offloading in Software Defined Network at Edge with Information Asymmetry: A Contract Theoretical Approach

The proliferation of highly capable mobile devices such as smartphones and tablets has significantly increased the demand for wireless access. Software defined network (SDN) at edge is viewed as one promising technology to simplify the traffic offloading process for current wireless networks. In this paper, we investigate the incentive problem in SDN-at-edge of how to motivate a third party access points (APs) such as WiFi and smallcells to offload traffic for the central base stations (BSs). The APs will only admit the traffic from the BS under the precondition that their own traffic demand is satisfied. Under the information asymmetry that the APs know more about own traffic demands, the BS needs to distribute the payment in accordance with the APs’ idle capacity to maintain a compatible incentive. First, we apply a contract-theoretic approach to model and analyze the service trading between the BS and APs. Furthermore, other two incentive mechanisms: optimal discrimination contract and linear pricing contract are introduced to serve as the comparisons of the anti adverse selection contract. Finally, the simulation results show that the contract can effectively incentivize APs’ participation and offload the cellular network traffic. Furthermore, the anti adverse selection contract achieves the optimal outcome under the information asymmetry scenario.     

Charging Information Collection Modeling and Analysis of GPRS Networks

Charging is one of the most important functionalities in a telecommunication service system. In a general packet radio service (GPRS) wireless network, the load of charging information flow depends on the intensity of call traffic and the size of charging records. During busy hours, the GPRS network might not be able to transfer charging records on a timely basis if new charging records are generated too fast. On the other hand, when a call happens, the related charging information must be collected and transferred to the billing system. If a failure of the data link occurs, a secondary data link must be employed to transfer the charging information. However, this redundant operation might result in charging information duplication. This paper formally addresses these two issues. A timed Petri net model is built to support the analysis of the charging system performance versus various factors when the system works in the normal status, which, in particular, gives the maximum supportable busy hour call attempts of the GPRS network. The Petri net approach is also used to model and verify the correctness of the redundancy operation in case a connection failure occurs.     

基于话务负荷的自适应绿色基站

构筑环境友好的生产模式,高效使用有限的能源,是运营商现阶段的研究重点。文章探讨了一种基于话务承载情况自适应调整能源消耗的模式,能在不损失业务承载能力和性能的前提下降低电力消耗,并针对现网的话务模型进行算法优化。应用结果显示该模式切实可行,利于推广,能在通信系统性能与节能目标间实现有效平衡。     

卫星移动通信终端的低功耗设计

低功耗设计是电子产品设计的重要环节,特别是对工作在野外环境的卫星移动通信手持终端类产品而言,低功耗设计是延长终端待机时间和使用寿命的重要途径。在对通信产品整机及各类组成单元功耗产生原理分析的基础上,分别从整机、单元电路、主要元器件及FPGA代码设计等几个方面入手,讨论了采用通用元器件设计的卫星通信终端的低功耗设计方法,并给出了改进设计后的低功耗设计效果。     

Improving IPTV Forwarding Mechanism in IEEE 802.16j MMR Networks Based on Aggregation

Internet protocol television (IPTV) service depends on the network quality of service (QoS) and bandwidth of the broadband service provider. IEEE 802.16j mobile multihop relay Worldwide Interoperability for Microwave Access networks have the opportunity to offer high bandwidth capacity by introducing relay stations. However, to actually satisfy QoS requirements for offering IPTV services (HDTV, SDTV, Web TV, and mobile TV) for heterogeneous users' requests, providers must use a video server for each IPTV service type, which increases the network load, especially bandwidth consumption and forwarding time. In this paper, we present a solution for forwarding IPTV video streaming to diverse subscribers via an 802.16j broadband wireless access network. In particular, we propose a new multicast tree construction and aggregation mechanism based on the unique property of prime numbers. Performance evaluation results show that the proposed scheme reduces both bandwidth consumption and forwarding time.     

Approach to problem of minimizing network power consumption based on robust optimization

In this paper, a green and robust optimization model is introduced to minimize network power consumption, which allows fluctuations of traffic demands between source‐destination pairs in the network. Our model is based on the green hose model, where the traffic is bounded by just total outgoing and incoming amount at each node. In addition to the green hose model, we use the ellipsoidal uncertainty set to allow a different type of fluctuations in traffic demands. Here, the total amount of squared errors in traffic demands is bounded by a constant which controls the total admissible fluctuations over the network. Applying the conic duality, we formulate our model in the form of mixed‐integer second order cone programming (MISOCP) problem. Furthermore, we establish a relationship between our model and the green hose model with bound of link traffic (HLT) model, an developed version of the hose model known as the HLT. Numerical results demonstrate that each of the MISOCP problems can be solved to its optimality in a reasonable time by a general MISOCP solver, and that the proposed model has different tendency in performance with the green hose and green HLT models.