两类周期查询式完全服务排队系统研究

本文对时间连续型非对称周期查询式完全服务排队系统进行了分析,并与时间离散型周期查询式完全服务排队系统(赵东风,1994)进行了对比研究。在两种系统取相同的系统参数值的条件下,给出两类排队服务系统的分析结果。     

两类周期查询式完全服务排队系统研究

本文对时间连续型非对称周期查询式完全服务排队系统进行了分析,并与时间离散型周期查询式完全服务排队系统（赵东风,１９９４）进行了对比研究。在两种系统取相同的系统参数值的条件下,给出两类排队服务系统的分析结果。     

周期查询式限定服务排队系统研究

本文采用嵌入马尔可夫链理论和概率母函数的方法,在离散时间状态下对周期查询式限定(K=1)服务排队系统进行了分析,讨论了报文的平均排队队长和平均等待时间的特性,改进了H。Tagai(1985)的分析结果。     

查询式完全服务排队模型分析

本文对查询式完全服务队系统，采用嵌入马乐可夫链理论和概率母了函数的分析方法进行了研究，给出了报文的平均延迟计算公式和有关的参数值。最后通过计算机模拟实验，给出了查询式完全服务排队系统的模拟数值的结果。理论计算与模拟结果相一致。     

多元最优信息分组延迟粒子群算法

在简要介绍基本PSO算法的基础上,提出多元最优信息分组算法:选择m个最优信息,分成m个组,每个微粒属于离自己最近的最优微粒所处的小组。当经过一定的运行延迟周期后,合并小组,直到只剩下最后一个小组。同时,对新算法进行描述并以典型优化问题的实例仿真验证了MGPSO算法的有效性。     

SCTP中引入基于排队延迟的拥塞算法

介绍SCTP拥塞控制机制,并在SCTP关联内引入基于排队延迟的FAST拥塞算法.通过比较分析基于排队延迟和基于数据丢失的两种拥塞算法,阐述基于排队延迟拥塞算法更加适合于网络发展的需求,并提出了SCTP中实现FAST拥塞控制机制的初步框架.     

多级门限服务轮询系统MAC离散时间控制协议模型分析

 本文提出了一种新的多级门限服务轮询系统MAC控制协议的分析模型.采用嵌入马尔可夫链理论,对离散时间的多级门限服务轮询系统进行了分析,获得了轮询时刻系统队长的概率母函数,精确解析了系统的平均排队队长、平均循环周期、信息分组的平均等待时延.通过对多级门限服务轮询系统的控制机理研究,分析获得了m控制参数的有效控制取值大小和系统的相关特性.多级门限服务轮询系统综合了基本门限服务轮询系统和完全服务轮询系统,在轮询系统的MAC控制协议的应用方面更为有效.     

有优先级的输出排队快速分组交换机性能研究

输出排队结构是快速分组交换中交换性能最佳的交换结构。本文研究输出排队结构交换任意种优先级业务的排队性能。分别在独立和相关到达两种情况下导出了任意优先级业务的平均排队长度等特征参数,发现当N×N规模互连网络的端口数N足够大时,两种业务到达模型的排队性能趋于一致。文中提出了一种数值迭代法来求取用二维Markov过程表示的高、低优先级分组队列长度的稳态解。计算机模拟结果证实了文中的分析。     

分组交换中分组流的概率特性与输出排队

本文分析快速分组交换中分组流的概率特性与输出排队。在输入分组流为复合泊松流的假设之下，论证了复合泊松流在分组交换过程中的叠加性、分解性、泊松性、马尔柯夫性、输出与输入的不变性等。然后，将输出分组流转换为连续时间的马尔柯夫链，分析了输出分组流的概率特性，并得到了输出排队长分布和充满缓冲器的概率。     

服务器个数随机可变的轮询系统分析

前人关于轮询系统的大量研究均以服务器无故障为前提。本文提出了一种容许服务器个数随机可变的多服务器轮询模型。同时考虑排队延迟与服务器故障／修复的影响，获得了顾客等待时间的平均值公式。     

离散时间闸门式多级门限服务的两级优先级轮询排队系统分析

本文提出了一种基于闸门式多级门限服务的两级优先级轮询系统.论文先构建了系统的排队分析模型,然后把模型中各个站点内的等待顾客数合起来设定为系统状态变量,对系统状态变量的概率母函数求二阶偏导后组成迭代方程组,联立求解后得到了站点的平均排队队长、顾客平均等待时间以及服务器查询周期等关键指标的完整数学解析表达式.最后,对该模型进行了仿真实验分析,实验结果与理论结果相一致.系统性能分析表明该轮询系统满足了周期性系统服务资源分配过程中业务多样性和弹性服务的发展需求,使得轮询控制策略应用方面更为广泛.     

离散时间并行优化门限服务轮询系统排队特性解析

针对周期式查询门限服务中流水线式调度效率低的问题,本文提出了一种并行优化门限服务轮询控制的系统服务资源调度策略.论文构建了轮询排队系统及其数学模型,先对系统状态变量的概率母函数求偏导得到一阶和二阶特性参数方程组,联立求解后推导出各个系统参数的完整数学解析表达式.仿真实验结果和理论计算值相一致.系统性能分析表明,该系统的队长和时延特性均得到了较大的提高,能够更好的适应密集数据环境下时延敏感性数据的服务需求.     

非对称周期查询限定服务系统解析

本文利用嵌入马尔可夫链理论和概率母函数的方法,对局域网络中离散时间状态下,有限缓冲器的非对称周期查询限定(k=1)服务系统 ∑ N i G_i/ ∑ N i G_i/1( ∑ N i G_i)/ ∑ N i S_i(FCFS)模型进行了解析,获得了系统第i队列的查询周期、信息分组平均队长、信息分组平均延时和信息分组丢失率的数学解析表达式.计算机模拟的结果表明了仿真与理论的一致性.     

Packet Delay Analysis of Symmetric Gated Polling System for DBA Scheme in an EPON

In this paper, we analyze the mean packet delay of a dynamic bandwidth allocation (DBA) scheme in an Ethernet passive optical network (EPON). We propose the interleaved polling system with a gated service discipline and a two-stage queue in order to investigate the delay performance of DBA scheme in an EPON. We assume that input packets arrive at an optical network unit (ONU) according to a Poisson process from several types of users. We use a continuous time queueing model in order to find the mean packet delay and the mean cycle time of an arbitrary packet. We obtain the closed form solution for the mean packet delay of the proposed gated polling system with a two-stage queue. We obtain another result on the mean packet delay by solving a system of linear equations derived from the moments of the queue length distribution. We give some numerical results to investigate the delay performances for the symmetric polling system with statistically identical stations. In addition, we compare numerical results on the closed form solution with numerical results on a system of linear equations.     

Mean Waiting Time Analysis in Finite Storage Queues for Wireless Cellular Networks

In this paper priority is assigned to the handover calls over new call attempts and blocked handover calls are placed in a finite storage queue. Total handover forced termination probability is evaluated and a suitable function for the mean service time at each position in the queue is theoretically estimated. Quality of service is obtained by introducing a threshold in the maximum waiting time of a handover call in the queue. In case the handover call mean service time at each queue position is found to be greater than this threshold, this call will be blocked. Simulation results show that this scheme provides satisfactory results for both types of calls. Spiros Louvros was born in Corfu Island, Hellas in 1971. He received his Bachelor in Physics from the University of Crete, Hellas and his Master of Science in telecommunications from the University of Cranfield, U.K. with a graduate scholarship from the Alexandros Onassis Institution. In 2004 he received his PhD from the University of Patras, Hellas, in mobile communications. He has worked for Siemens as a microwave engineer, for Vodafon-Hellas as a switching engineer and for Cosmote S.A. as section manager in the Operations, Maintenance & Optimization Department. His current occupation is in the Telecommunication Systems & Networks Department, Technical University of Messologi, Hellas, as an Assistant Professor. He holds several papers in international journals and conferences and he has participated in several research projects regarding mobile communications. His area of interest is in mobile networks, telecommunication traffic engineering, wireless ATM and optical communications and is documented by over 30 papers in international literature and conference proceedings. He is member of FITCE and Hellenic Physics Union. Gerasimos Pylarinos – Stamatelatos was born in Kefalonia, Greece in 1966. He receieved the B.E. in Electrical and Computer Systems Engineering from Monash University, Melbourne, Australia in 1992 and the B.E. in Electrical and Computer Systems Engineering from the University of Patras, Greece in 1994. He received the M.Sc. in Data Communications Systems from Brunel University, United Kingdom. He is currently pursuing the PhD degree at the University of Patras Greece. He has worked at Philips Radio Communication Systems, Melbourne, Australia developing hardware for mobile radio communication systems for 2 years. He subsequently worked as project manager in the Research and Development department at Intracom Radio Communication Systems, Greece for 7 years. He is now manager of the Biomedical Engineering department of Kefalonia Hospital, Greece. His research interests lie in the areas of 3G and 4G wireless communications. S. Kotsopoulos was born in Argos-Argolidos (Greece) in the year 1952. He received his B.Sc. in Physics in the year 1975 from the University of Thessaloniki, and in the year 1984 got his Diploma in Electrical and Computer Engineering from the University of Patras. He did his postgraduate studies in the University of Bradford in United Kingdom. And he is an M.Phil and Ph.D. holder since 1978 and 1985 correspondingly. Currently he is member of the academic staff of the Department of Electrical and Computer Engineering of the University of Patras and holds the position of Associate Professor. Since 2004, is the Director of the Wireless Telecommunications Laboratory and develops his professional life teaching and doing research in the scientific area of Telecommunications, with interest in mobile communications, interference, satellite communications, telematics applications, communication services and antennae design. Moreover he is the (co)author of the book titled “mobile telephony”. The research activity is documented by more than 160 publications in scientific journals and proceedings of International Conferences. Associate Professor Kotsopoulos has been the leader of several international and many national research projects. Finally, he is member of the Greek Physicists Society and member of the Technical Chamber of Greece.     

多服务器轮询系统分析（Ⅱ）──穷尽服务系统

多服务器轮询模型在分布式系统及多通道网络系统中有着实际应用价值。本文首次对采用穷尽服务策略的多服务器轮询模型进行了分析，在周期特性分析的基础上给出了顾客等待时间的均值及平均分公式。     

候时抖动抑制方法研究

针对正码速调整、正／零／负码速调整和指针调整等，提出并讨论了相应的可以有效减小候时抖动的方法。