An extended master-equation approach applied to aggregation in freeway traffic

We restudy the master-equation approach applied to aggregation in a one-dimensional freeway, where the decay transition probabilities for the jump processes are reconstructed based on a car-following model. According to the reconstructed transition probabilities, the clustering behaviours and the stochastic properties of the master equation in a one-lane freeway traffic model are investigated in detail The numerical results show that the size of the clusters initially below the critical size of the unstable cluster and initially above that of the unstable cluster all enter the same stable state, which also accords with the nucleation theory and is known from the result in earlier work. Moreover, we have obtained more reasonable parameters of the master equation based on some results of cellular automata models.     

Steady state speed distribution analysis for a combined cellular automaton traffic model

Cellular Automaton （CA） based traffic flow models have been extensively studied due to their effectiveness and simplicity in recent years. This paper develops a discrete time Markov chain （DTMC） analytical framework for a Nagel-Schreckenberg and Fukui Ishibashi combined CA model （W^2H traffic flow model） from microscopic point of view to capture the macroscopic steady state speed distributions. The inter-vehicle spacing Maxkov chain and the steady state speed Markov chain are proved to be irreducible and ergodic. The theoretical speed probability distributions depending on the traffic density and stochastic delay probability are in good accordance with numerical simulations. The derived fundamental diagram of the average speed from theoretical speed distributions is equivalent to the results in the previous work.     

Performance analysis of an integrated scheme in optical burst switching high-speed networks

A new integrated scheme based on resource-reservation and adaptive network flow routing to alleviate contention in optical burst switching networks is proposed. The objective of the proposed scheme is to reduce the overall burst loss in the network and at the same time to avoid the packet out-of-sequence arrival problem. Simulations are carried out to assess the feasibility of the proposed scheme. Its performance is compared with that of contention resolution schemes based on conventional routing. Through extensive simulations, it is shown that the proposed scheme not only provides significantly better burst loss performance than the basic equal proportion and hop-length based traffic routing algorithms, but also is void of any packet re-orderings.     

Finite Linear Spaces II

Batten and Beutelspacher have characterized Finite Linear Spaces with lines of size n,n + 1 and n + 2, and with v (n + 1)²for n 22, and some of the cases for smaller n. In this article, using the structuredapproach we presented in our earlier article [8], we complete this characterization for smalln.     

Loss Probabilities of Hand-in Traffic under Various Protocols,I: Models and Algebraic Results

Mobile telephone traffic business demands that a given base station be able to handle both newly originating traffic and hand-in traffic from neighbouring base stations, with priority to be given to the latter, existing traffic. Starting from a baseline standard model in which all channels are available to all traffic, this note examines three other models, each with its own access control protocol that allocates a reserve capacity R amongst the N _tot channels to give priority to the hand-in traffic. These different protocols give different loss probabilities for the two types of traffic. All the results are proved on the basis of assuming a Poisson arrival process and independent exponential service times. This paper concentrates on presenting explicit expressions for many of the loss probabilities, some of them given by the Erlang B loss formula or variants, as well as simple approximations and bounds. A companion paper presents results comparing the various models.     

Linear discriminant analysis in network traffic modelling

It is difficult to give an accurate judgement of whether the traffic model fit the actual traffic. The traditional method is to compare the Hurst parameter, data histogram and autocorrelation function. The method of comparing Hurst parameter cannot give exact results and judgement. The method of comparing data histogram and autocorrelation only gives a qualitative judgement. Based on linear discriminant analysis we proposed a novel arithmetic. Utilizing this arithmetic we analysed some sets of data with large and little differences. We also analysed some sets of data generated by network simulator. The analysis result is accurate. Comparing with traditional method, this arithmetic is useful and can conveniently give an accurate judgement for complex network traffic trace. Copyright © 2005 John Wiley & Sons, Ltd.     

Research on the measurement of the price change of telecom services in China

1 Introduction The telecom service price (TSP) is the focus of benefit of distribution between telecom enterprises and customers. With the opening of the telecom service market and the increasing competition, the changes in the TSP became more frequent, e…     

MANET中基于动态拓扑的多路径自适应流量分配算法

移动自主网络中的大多数多路径路由方案几乎没有考虑流量分配和负载均衡问题。显然,无论路径质量好坏给每条路径分配相同的负荷,会大大降低多路径路由机制的性能,最后会大幅增加网络的通信开销和节点的处理开销。围绕这些问题,提出了一个基于动态拓扑的多路径自适应动态流量分配方案,根据路径质量的权重来动态地给多条路径分配数据流量的比例。大多数情况下仅用局部的信息做路由决定,因此大大减少网络开销。在OPNET模拟平台中实现了这个协议,结果表明,该方案对于MANET网络来说的确是一个可行的方法。     

Simple bounds for closed queueing networks

Consider a closed Jackson type network in which each queue has a single exponential server. Assume that N customers are moving among k queues. We establish simple closed form bounds on the network throughput (both lower and upper), which are sharper than those that are currently available. Numerical evaluation indicates that the improvements are significant.     

ATM网络中突发业务的漏桶算法分析

统计复用可以使突发业务获得较高的频带利用率，但必须对输入的业务量进行恰当的控制，否则会造成严重的网络拥塞，漏桶法是ＡＴＭ网络基于速率调节进行业务量控制的一种重要的方法，本文对突发业务的漏桶算法进行了分析，得出了突发业务的漏桶性能与输入业务统计参数和漏桶参数之间关系的解析式，计算机模拟结果表明它与理论分析的一致性。