随机仿真优化的一类遗传序优化框架

针对仿真优化问题存在随机性、计算费时、解空间巨大、多极小等难点,结合遗传算法的并行遗传搜索、最优计算量分配以及序优化的目标软化和序比较思想提出一类遗传序优化框架,进而讨论了该方法的收敛性和具体实施问题,最后指出了进一步的研究内容.     

无线通信网络呼叫接纳控制策略研究综述

呼叫接纳控制（CAC）是无线通信网络无线资源管理中一个重要的组成部分,CAC策略依据一定的准则决定呼叫到达请求的允许接入或拒绝接入,其中策略设计的好坏直接影响着网络的性能和资源利用率。20多年来,CAC策略得到了广泛地研究,极大地改善了网络呼损率、中断率、分组延时、丢包率和吞吐率等性能。简要介绍了无线通信网络中与CAC的一些相关背景及CAC策略的功能定位与作用,重点介绍了近年来CAC研究的一些新的成果,并分析了这些成果仍然存在的一些问题,最后给出了对于CAC进一步研究的探讨。     

Proposed high speed packet switch for broadband integrated networks

The design of a high speed, broadband packet switch with two priority levels for application in integrated voice/data networks is presented. The packet switch can efficiently cope with 128 byte packets converging on it from eight 140 Mbit/s dynamic time division multiplexed fibre optic links. The packet switch throughput varies with the load and traffic composition, and the delay experienced by voice and data packets is within 300 μs and 3 ms, respectively. The design is implemented by task-sharing in a multi-processor configuration. The design of the packet switch, including its subsystems, is detailed here.     

适合于移动多媒体网络的呼叫接纳控制算法

移动多媒体网络应该能够同时支持传统的数据业务和实时交互式多媒体业务,并能够为用户提供QoS保证.在无线移动网中提供QoS保证,呼叫接纳控制扮演着重要的角色.通过对呼叫接纳算法中资源预留方案进行了分析总结,提出了一种适合于移动多媒体网络的自适应呼叫接纳控制算法.     

Solution of trim-loss problem by an integrated simulated annealing and ordinal optimization approach

This work presents a novel optimization method capable of integrating ordinal optimization (OO) and simulated annealing (SA). A general regression neural network (GRNN) is trained using available data to generate a rough model that approximates the response surface in the feasible domain. A set of good enough candidates are generated by conducting a (SA) search on this rough model. Only candidates accepted by the SA search are actually tested by evaluating their true objective functions. The GRNN model is then updated using these new data. The procedure is repeated until a specified number of tests have been performed. The method (SAOO+GRNN) is tested the well-known paper trim loss problem. SAOO+GRNN approach can substantially reduce the number of function calls and the computing time far below those of simple ordinal optimization method with such as horse race selection rule, as well as straightforward simulated annealing.     

Implementation of call admission control scheme in next generation mobile communication networks using particle swarm optimization and fuzzy logic systems

In the present and next generation wireless networks, cellular system remains the major method of telecommunication infrastructure. Since the characteristic of the resource constraint, call admission control is required to address the limited resource problem in wireless network. The call dropping probability and call blocking probability are the major performance metrics for quality of service (QoS) in wireless network. Many call admission control mechanisms have been proposed in the literature to decrease connection dropping probability for handoffs and new call blocking probability in cellular communications. In this paper, we proposed an adaptive call admission control and bandwidth reservation scheme using fuzzy logic control concept to reduce the forced termination probability of multimedia handoffs. Meanwhile, we adopt particle swarm optimization (PSO) technique to adjust the parameters of the membership functions in the proposed fuzzy logic systems. The simulation results show that the proposed scheme can achieve satisfactory performance when performance metrics are measured in terms of the forced termination probability for the handoffs, the call blocking probability for the new connections and bandwidth utilization.     

基于禁忌算法的快速公交网络系统仿真优化

针对传统数学规划方法处理BRT网络系统优化存在的局限性,提出了一类直达乘客量最大化的BRT网络规划问题并建立了数学模型。设计了该优化模型的禁忌算法。多次仿真实验结果表明模型合理,算法有效。     

无线光通信网络建模与仿真

采用面向对象的方法自顶向下地对无线光(FSO)通信网络进行了分析建模.根据FSO的实际特点设计出关键算法,抽象出FSO载荷基类、环境基类并派生出FSO节点类、FSO链路类和FSO网络类,并由此建立了FSO网络的仿真模型.采用事件驱动的方法设计程序的流程,利用时间同步机制处理不同的仿真通信线程间的数据交互.     

无线蜂窝网络呼叫接入控制仿真平台的设计与实现

介绍了蜂窝网络无线通信中的呼叫接入控制(CAC)的特点,描述了基于面向对象的事件驱动技术的仿真平台的设计思想和仿真系统的优化,对仿真平台的物理模型进行了分析,并给出平台的运行过程。最后给出了无预留信道和固定预留信道的接入控制算法的进行了仿真,并对仿真的结果进行了分析,试验结果符合理论分析。     

基于CHEMSTAR的在线模拟优化系统

以青岛科技大学计算机与化工研究所的CHEMSTAR化工之星为平台,开发了基于CHEMSTAR的在线模拟优化系统。提出了系统形成的基本思路,建立了系统的总体结构,本系统可以在线的实现过程数据校正和模拟优化。最后,应用工业实例来说明基于CHEMSTAR的在线模拟优化系统的可行性和实用性。     

Voice/data integration on Ethernet — backoff and priority considerations

Astudy of the CSMA/CD protocol as given in the Ethernet specifications, for real time (voice in particular) and mixed voice/data environments is described. The objectives of the study were to predict the Ethernet's behaviour under the current protocols, to point out potential improvements within the realm of the current specifications, and to improve understanding of the network behaviour in these environments. Results are given in terms of relative performance of the various system measures given as a function of system and traffic models. It is shown that the support provided to real time voice on Ethernet strongly depends on the assumptions made with regard to the coexisting data user's traffic and that with certain data traffic patterns the observed voice delay is much worse than previously reported. Finally, it is shown that without violating the Ethernet network specification, voice service can be improved by simple adjustments of the Ethernet retransmission ‘backoff’ algorithm.     

火箭炮营通信仿真系统控制子系统的研究

为了满足部队和院校对新装备的训练、教学需要,设计了某型火箭炮营通信仿真系统.主要介绍了通信仿真系统的总体设计,着重研究了控制子系统的设计和功能模块的划分.在具体实现过程中基于VC++编程语言,运用多种网络通信方式和差错控制方法,以及数据库访问技术,实现了控制机子系统对电台分组和维护通信子网的逻辑过程.实际应用表明,控制机子系统运行可靠,达到了设计要求.     

具有通信时延和有向网络的多智能体分布式优化

本文对非平衡有向拓扑下一阶多智能体系统的分布式优化问题进行研究.研究的智能体在与邻居的通信过程中都有一个变化的时延.本文的目标是找到使得目标函数f(x)=(NΣi=1)fi(xi)最小的智能体的状态.提出了一种基于有向图的拉普拉斯矩阵的零特征值对应的左特征向量和智能体的局部信息的控制器.在这项研究中,去掉了fi(xi)...     

A hybrid optimization/simulation approach for a distribution network design of 3PLS

Third party logistics service providers (3PLs) are playing an increasing role in the management of supply chains. Especially in warehousing and transportation services, a number of clients expect for 3PLs to improve lead times, fill rates, inventory levels, etc. Hence, these 3PLs are under pressure to meet various clients’ service requirements in a dynamic and uncertain business environment. As a result, 3PLs should maintain an efficient distribution system of high performance competitive advantages. In this paper, we propose a hybrid optimization/simulation approach to design a distribution network for 3PLs in consideration of the performance of the warehouses. The optimization model uses a genetic algorithm to determine dynamic distribution network structures. Subsequently, the simulation model is applied to capture the uncertainty in clients’ demands, order-picking time, and travel time for the capacity plans of the warehouses based on service time. The approach is applied to an example problem for examining its validity.     

大规模稀疏矩阵在并行应用中的通信优化研究*

为了提高并行应用系统的效率,研究了针对大型稀疏矩阵的压缩通信问题.通过对矩阵压缩通信过程中矩阵稀疏度、网络带宽、处理器计算能力之间的关系进行定量分析,推导出稀疏度下界计算公式.通过对不同稀疏度情况下算法所取得的效率进行分析,总结出压缩通信中稀疏度与通信效率之间的函数关系.结合油藏数值模拟的应用实例,设计实现了稀疏矩阵的压缩通信算法.结果表明本算法在稀疏矩阵通信方面效率有明显的提高.     

二维宏观拟颗粒并行模拟程序通信性能优化策略

随着粒子模拟并行计算在相关领域应用的不断深入和并行节点计算能力的不断增强,粒子模拟并行程序中通信耗时对整体性能的影响越来越显著,甚至成为主要性能瓶颈.本文在分析影响并行程序通信性能多种因素的基础上,从进程划分方式选择、通信协议优化的角度,对1个典型粒子模拟并行程序——二维宏观拟颗粒并行模拟程序在千兆以太网环境下的通信性能的优化策略进行了测试研究,通过改进并行进程划分方式,采用用户级通信协议等方法,使测试程序通信性能获得明显提高,进而提出了粒子模拟并行程序通信性能优化的思路和建议.     

QoS routing optimization strategy using genetic algorithm in optical fiber communication networks

This paper describes the routing problems in optical fiber networks, defines five constraints, induces and simplifies the evaluation function and fitness function, and proposes a routing approach based on the genetic algorithm, which includes an operator [OMO] to solve the QoS routing problem in optical fiber communication networks. The simulation results show that the proposed routing method by using this optimal maintain operator genetic algorithm (OMOGA) is superior to the common genetic algorithms (CGA). It not only is robust and efficient but also converges quickly and can be carried out simply, that makes it better than other complicated GA.     

Buffer analysis of an integrated voice and data terminal

Current research activities in computer networks tend to emphasize the integration of services such as voice and data by designing networks that take into account the performance requirements of these services. In some cases, however, design and implementation of a totally new network may not be feasible. An alternative approach in such cases would be to integrate the services at the terminal level. Such an integrated terminal could also be widely used in future office automation systems. The performance of such an integrated terminal is assessed with the assumption that the terminal is connected to a voiceband channel. The analysis indicates the performance limits on the application imposed by the buffer size at the terminal and the large fluctuation of delay performance for data traffic. A window-type flow control for data traffic is also considered. By appropriately choosing the buffers in the terminal and window size, both voice and data traffic service requirements can be met.     

自适应MIMO-OFDM通信系统中基于CPSO-PF的状态优化与性能仿真

针对MIMO-OFDM通信系统状态参数不能随信道干扰噪声适时调整而严重影响通信质量的实际问题,论述了MIMO-OFDM通信系统的传输原理与性能参数,研究了混沌粒子群优化算法(CP-SO)及粒子滤波(PF)的性能特点,提出了基于CPSO粒子滤波(CPSO-PF)的自适应MIMO-OFDM通信系统模型;设计了基于CPSO-PF的自适应状态优化算法,并结合典型干扰噪声环境对系统误码率进行了仿真。仿真实验结果表明,基于CPSO-PF的自适应状态优化能够有效抑制噪声干扰,显著改善自适应MIMO-OFDM通信系统的误码性能。     

基于多目标满意优化的计算机通信网流量和容量分配

将满意优化理论应用到计算机通信网中,提出了基于多目标满意优化的计算机通信网优化设计方法,通过设计满意度函数,构造出计算机通信网的满意优化数学模型,并用改进遗传算法实现计算机通信网的容量和流量分配的满意优化设计。仿真结果显示,所设计的网络具有更满意的综合性能指标,证实了该方法的有效性和实用性。