基于移动通信的城市停车诱导信息系统设计

随着汽车保有量不断增加,停车难已成为城市交通普遍问题。从分析城市停车诱导系统功能和提高停车设施利用率的角度出发,结合实际城市交通情况,采用PGIS技术,提出一个整体性、实时动态的停车诱导信息系统。该系统设计通过仿真验证有效．因此将为城市交通管理控制、驾驶员出行提供更准确和有效的诱导决策辅助信息。     

Review and perspective on encrypted traffic identification research

Considering the importance of encrypted traffic identification technology and existing research work,first,the type of encrypted traffic identification according to the demand of traffic analysis were introduced,such as protocols,applications and services.Second,the encrypted traffic identification technology was summarized,and identification technology was compared from multiple views.Third,the deficiencies and the affecting factors of the existing encrypted traffic identification technologies were induced,such as tunneling,traffic camouflage technology,new protocols of HTTP/2.0 and QUIC.Finally,prospect trends and directions of future research on encrypted traffic identification were discussed.     

全球网络中立进展及对OTT的影响

随着互联网的普及，特别是移动互联网的日益广泛，网络中立问题仍然是热点问题，从美国逐步扩展到全球其他地区，如亚洲、欧洲和南美洲等。目前网络中立问题主要聚焦在对运营商网络管理策略合法性的争论之上，特别是对OTT服务的管理问题。由于OTT应用不断涌现，给电信运营商网络带来很大压力，多国运营商采取措施应对OTT。     

IP网流量工程的一种权值设置方法

提出一种新的基于传统路由协议的流量控制方法。该方法首先在不限制总流量条件下求解最小化最大连接利用率。然后在固定最大连接利用率条件下最小化总流量。由此求得最优流量分配方案并从其对偶问题中求出各连接的权值配置。实验结果显示，文中算法较现有算法明显降低最大连接利用率，并且增加了稳定性。     

Optimization of listening time of S-MAC for wireless sensor networks

In wireless sensor networks, sensor nodes are usually battery-operated computing and sensing devices, hence operations are limited by the initially equipped batteries, which are hard to be recharged or replaced. In this sense, saving energy consumption becomes significant. As most energy waste is from the always-on wireless interface, S-MAC is suggested to reduce energy consumption by introducing periodic listen/sleep scheme. However, when designing the listening time, S-MAC fails to consider the traffic distribution factor. In this article, an optimization for this scheme is proposed based on the distribution model. Evaluations show that the optimized S-MAC achieves considerable improvement in energy and latency.     

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.     

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.