Response Surface Methodology Applied to Toll Plaza Design for the Transition to Electronic Toll Collection

Electronic toll collection (ETC) holds the promise of greatly reduced congestion at toll roads, bridges, and tunnels. Using automatic vehicle identification (AVI), vehicles are charged a toll as they drive non-stop through a tollbooth. Since a transition to the AVI-dominated toll plaza cannot occur overnight, a plan for the increasing use of AVI tollbooths that does not increase congestion for non-AVI vehicles is needed. Experiments using a simulation model of a typical toll plaza with varying mixes of vehicle types and tollbooth allocations provided data for four output measures: vehicle volume, average queue length, average waiting time, and tollbooth utilization. Multiple linear regression analysis was then applied to fit response surfaces for each measure. The response surfaces provided the optimum tollbooth allocation for a given mix of vehicles. Two decision rules were evaluated based on their ability to specify near-optimum tollbooth allocations for varying mixes of vehicle types using vehicle volume as the output measure.     

基于收费数据的交通拥堵初发点计算

目前,在高速公路发生拥堵后,如何利用海量收费数据快速准确地得到高速公路交通拥堵初发点,仍然缺少满意的解决方案。经过对湖南省高速公路收费数据检索,提取出车辆出入站时刻、行车时间和车型等相关交通特征参数,依据这些参数特点,提出了一种计算相邻两收费站之间的交通拥堵初发点的计算方法。该方法通过选取同路段上的快、慢2种车型建立方程组,然后根据分析收费数据提取相应的变量代入方程组中,从而计算得出拥堵初发点信息。结果表明,该方法可以有效地计算得出相邻两个收费站之间路段上的拥堵初发点位置和初发时刻。对今后出行服务,运行效率评估和交通组织管理等具有重要的现实意义。     

高速公路串行收费站通行能力仿真研究

针对基于车流到达服从标准泊松分布的并行收费站排队服务模型在交通流的时空复杂性、成本、可靠性等方面存在的不足,提出基于元胞自动机建模与仿真的串行收费站布设方式的通行能力、延误及布设个数的分析方法。研究结论表明：串行收费站的通行能力随布设个数的增加而增大,但增大幅度缓慢降低;串行收费站的车均延误以80%通行能力的流量水平为分界点,随着流量继续增大,车均延误急剧上升。给出了不同的流量水平所对应的串行收费站最佳布设个数。     

A general simulator approach to ETC toll traffic congestion

This study proposes a process simulation-based approach using a general simulator to offer solutions for Electronic Toll Collection System (ETC) traffic expressway problems at toll plazas. First, the paper describes an overview of the ETC system in general around the world as well as in Japan, and clarifies the ETC traffic problems that occur on Japanese expressways and hinder the diffusion of the ETC system in Japan. Then the paper describes our approach of process simulation to this issue, using a general simulator to show how the basic model in this study has been built and how its internal procedures are defined. The basic model has been reviewed by a mathematical approach with results shown in the following section. Into this basic model, we applied some actual traffic data obtained from one of the ETC I.C. sites. By using ETC traffic simulations, this study verifies the feasibility of the model. This paper proposes two kinds of solutions to the ETC traffic issue. One solution is gate management, which coordinates ETC/general switching to make the best use of the gates. The key issue here is how to find the best time for gate switching. Another solution is layout redesign, which employs an appropriate new layout for toll plazas. The issue here is to design an effective layout to reduce traffic jams. On-site reviews of either solution represent an unrealistic approach. Therefore, this research utilizes a simulation-based approach to identify these solutions. Using the results of simulation, feasibility of this approach is discussed. Received May 2005 / Revised: January 2006     

多业务流量预测动态带宽分配方法

静态带宽资源分配方法或基于业务分类的动态带宽分配方法等很难适应业务流特性,无法保证各级业务的服务质量。设计了流量预测及带宽分配模型,给出了流量预测计算方法,提出多业务流量预测动态带宽分配方法（MSTPDBA）,该方法基于业务预测流量的大小进行可用带宽的重新分配。仿真实验证明了MSTPDBA的有效性,能控制不同业务的时延,并提高了系统带宽资源的利用率。     

User-level performance of elastic traffic in a differentiated-services environment

We consider a system with two service classes, one of which supports elastic traffic. The traffic characteristics of the other class can be completely general, allowing streaming applications as an important special case. The link capacity is shared between the two traffic classes in accordance with the generalized processor sharing (GPS) discipline. GPS-based scheduling algorithms, such as weighted fair queuing, provide a flexible mechanism for service differentiation and prioritization.

We examine the user-level performance of the elastic traffic. The elastic traffic users randomly initiate file transfers with a heavy-tailed distribution. Within the elastic traffic class, the active flows share the available bandwidth in an ordinary processor-sharing (PS) fashion. The PS discipline has emerged as a natural paradigm for evaluating the user-perceived performance of bandwidth sharing algorithms like TCP. For a certain parameter range, we establish that the transfer delay incurred by the elastic traffic flows is asymptotically equivalent to that in an isolated PS system with constant service rate. This service rate is only affected by the streaming traffic through its average rate. Specifically, the elastic traffic is largely immune from possible adverse traffic characteristics or performance degradation due to prioritization of the streaming traffic. This confirms that GPS-based multiplexing mechanisms achieve significantly better performance for both traffic classes than a static bandwidth partitioning approach.     

VoIP development in China

Several factors have spurred the explosive growth of VoIP phone use in China, including customer incentives such as improved voice quality and lower cost per call, and provider incentives such as higher profits and upgrade paths to next-generation technologies. The voice over Internet protocol, also called IP telephony, offers a new type of service that uses the Internet protocol, intranets, and extranets to deliver voice information. In contrast to traditional telephone services, which operate through a circuit-switched network, VoIP uses a packet-switched network. This distinction results in differences in implementation, quality of service (QoS), and operating costs. Since the service was introduced to the public in China in April 1999, VoIP toll telephone traffic has increased with astonishing speed. By the end of 2002, VoIP toll telephone traffic had surpassed traditional toll telephone traffic in China in both domestic longdistance and international call areas, including phone calls to and from Hong Kong, Macao, and Taiwan.     

实时交通信息服务数据组织与基于JAVA的系统实现

相对于单纯道路网络信息和历史经验交通信息,实时交通信息对于出行者出行决策具有更为重要的意义。随着实时交通信息获取手段的多样化和普及化,更富生命力的实时交通服务系统已经纳入应用日程。首先分析总结了公众对于实时动态交通信息的需求状况,将与导航和出行密切相关的实时道路交通信息分为交通事件和交通流信息两大类,对交通事件,根据其几何特征,进一步分为点事件、线事件、面事件和关系事件。基于J2ME/J2EEE软件开发架构,Post SQL与Post GIS的时空交通数据管理模式,研发了中心式的实时交通信息服务系统原型,并对典型的交通事件和交通流信息在移动终端模拟器进行了时空表达示例。     

TPII: tracking personally identifiable information via user behaviors in HTTP traffic

It is widely common that mobile applications collect non-critical personally identifiable information(PII)from users'devices to the cloud by application service providers(ASPs)in a positive manner to provide precise and recommending services.Meanwhile,Internet service providers(ISPs)or local network providers also have strong requirements to collect PIIs for finer-grained traffic control and security services.However,it is a challenge to locate PIIs accurately in the massive data of network traffic just like looking a needle in a haystack.In this paper,we address this challenge by presenting an efficient and light-weight approach,namely TPII,which can locate and track PIIs from the HTTP layer rebuilt from raw network traffics.This approach only collects three features from HTTP fields as users'behaviors and then establishes a tree-based decision model to dig PIIs efficiently and accurately.Without any priori knowledge,TPII can identify any types of PIIs from any mobile applications,which has a broad vision of applications.We evaluate the proposed approach on a real dataset collected from a campus network with more than 13k users.The experimental results show that the precision and recall of TPII are 91.72%and 94.51%respectively and a parallel implementation of TPII can achieve 213 million records digging and labelling within one hour,reaching near to support 1Gbps wirespeed inspection in practice.Our approach provides network service providers a practical way to collect PIIs for better services.     

面向高速公路大数据的短时流量预测方法

针对高速公路传统的短时交通流预测方法适用数据规模小、全网预测效率较低、数据的时空关系被忽视等问题，提出一种结合了K近邻（KNN）模型且面向高速大数据的短时交通流预测方法。首先，对模型的K值和距离度量进行调优，利用交叉验证进行模型参数的对比实验；然后，考虑数据内在的业务时空关联，建模基于时空特性的特征向量；最后，在大数据环境下建立回归预测模型，以最优参数的模型实现预测。实验结果表明，与传统时间序列模型相比，所提方法一次可预测出全站点的流量，单次运行速度快，效率提高了77%，平均绝对百分比误差（MAPE）和绝对百分比误差中位数（MDAPE）均有明显减低，且具有良好的水平扩展性。     

Secure pay while on move toll collection using VANET

Manual toll tax collection requires vehicles to stop and pay. This results in long delays that nullify the aim of rapid transit of the toll roads. Existing pay as you drive techniques require offline payment and privacy breaching authentication process. In this paper, a VANET based privacy preserving secure pay while on move toll tax payment scheme is presented. The payment process is based on blinded coin in which the coin is obtained from the bank offline. As member of the VANET, a vehicle is a priori authenticated and makes online payment during the period it passes through the plaza.     

基于粗集理论的交通事故死亡人数时间分布分析

利用粗集理论,以事故死亡人数为指标,分别以月、周、日和小时为时间粒度,以吉林省某高速公路1999年至2004年发生的交通事故统计数据为例,对道路交通事故死亡人数的时间分布规律进行分析。结果表明,道路交通事故死亡人数的分布与时间有密切的关系,并且不同时间粒度对死亡人数分布影响的重要程度又存在显著差别。     

一种计算话务量的进化神经网络方法

话务量是度量用户使用电话设备频繁程度的一个重要参量,由于目前话务分布呈现出显著的立体性、多业务性和非泊松流等特点,不能直接应用欧兰Ｂ公式进行计算。为此,从计算智能出发提出一种基于PSO算法的进化神经计算方法,主要包括话务量及其相关参量的获取、神经网络结构的优化、基于PSO算法的网络训练,以及话务量计算等步骤。通过对河北省某市小灵通业务的详细研究,利用近半年来的话务量与无线阻塞率、来话接通率和掉话率等参量构成的样本信息进行建模,所计算的话务量精度高,表明其方法切实可行且效果显著。     

基于网格技术的交通信息服务平台的设计与实现

介绍了网格技术在交通信息服务平台中的应用策略,给出了一个基于网格技术的交通信息服务平台（SHGTISP）的服务部署和信息流程及其主要模块的主要工作流程。阐述了网格中间件在SHGTISP中的应用和SHGTISP中的并行算法设计要点,以及实现SHGTISP的开发环境和系统运行环境。实践表明,网格技术能为交通信息服务平台提供高性能的计算和开放的资源共享能力。     

Offloading mobile data traffic for QoS-aware service provision in vehicular cyber-physical systems

Owing to the increasing number of vehicles in vehicular cyber-physical systems (VCPSs) and the growing popularity of various services or applications for vehicles, cellular networks are being severely overloaded. Offloading mobile data traffic through Wi-Fi or a vehicular ad hoc network (VANET) is a promising solution for partially solving this problem because it involves almost no monetary cost. We propose combination optimization to facilitate mobile data traffic offloading in emerging VCPSs to reduce the amount of mobile data traffic for the QoS-aware service provision. We investigate mobile data traffic offloading models for Wi-Fi and VANET. In particular, we model mobile data traffic offloading as a multi-objective optimization problem for the simultaneous minimization of mobile data traffic and QoS-aware service provision; we use mixed-integer programming to obtain the optimal solutions with the global QoS guarantee. Our simulation results confirm that our scheme can offload mobile data traffic by up to 84.3% while satisfying the global QoS guarantee by more than 70% for cellular networks in VCPSs.     

基于WSDM的校园网流量监测系统设计与实现

设计了一种基于WSDM的校园网流量监测系统。以校园网为实验环境,设计并实现了该流量监测系统的原型。通过测试结果分析,证明该系统比传统流量监测系统具有更多的流量采集方式,更好的松耦合性,更容易进行扩展以及服务管理,对基于分布式计算的网络管理系统模型的开发和设计有较好的借鉴价值。     

The model of servicing the real-time traffic and data with a dynamically changeable transmission speed

A model is built up of the joint transmission of the traffic of real-time services and the data traffic admitting a delay. The real-time traffic has the advantage in the occupation and use of the channel resource. It is expressed in terms of a decrease of the data transmission speed to a certain preassigned minimum value. As a free channel resource appears, the data transfer speed increases. The scheme is investigated of the occupation of the channel resource and formal definitions are given of the basic quality indices of the joint service of requests. A solution is considered of the problem for estimating the data traffic volume that can be transmitted together with the traffic of real-time services in the fulfillment of the prescribed restrictions on the delay.     

A study on the monitoring model development for quality measurement of internet traffic

The recent trend of integration among new network services such as the long-term evolution (LTE) based on internet protocol (IP) needs reputable analyses and prediction information on the internet traffic. The IP along with increased internet traffics due to expanding new service platforms such as smartphones will reflect policies such as network QoS according to new services. The establishment of monitoring methods and analysis plans is thus required for the development of internet traffics that will analyze their status and predict their future. The paper with the speed of Internet traffic model is developed for monitoring the state of the experiment and verified. The problem is that the proposed service Internet service provider (ISP) to resolve the conflict between the occurrences can be considerably Internet traffic and that the state of data may be helpful in understanding. The paper advancement policy to reflect the network traffic volume of Internet services and users irradiation with increased traffic due to the development and management of the analysis was carried out experimental measurements.     

基于延迟函数次梯度启发式道路交通补偿策略

拥挤收费被认为是解决交通拥挤的有效方法,解决道路交通拥堵的主要想法是,对于有些容易造成拥堵的道路进行收费,而对于其他未充分利用的道路进行适当补偿,对此提出一种基于延迟函数的次梯度启发式道路交通补偿策略。首先,给出道路集的收费/补贴的非线性规划模型,主要是基于Beckmann最小化目标函数实现,然后利用库恩-希尔斯条件和拉格朗日乘子建立模型的条件约束;其次,基于启发式算法建立道路交通的定价补偿策略,利用边际成本建立延迟函数分析模型,然后基于次梯度法进行模型的优化;最后,通过在真实道路网络上的仿真实验,显示所提算法在旅行时间、交通流量、收敛性等指标上均具有较好的性能,验证了算法的有效性。     

基于SLA流量异常监测系统的研究与实现

随着网络规模的不断升级,网络流量特征的相关研究已经成为网络性能分析主要方向之一。通过对网络流量异常情况的监测,分析VPN流量和远程员工的行为,提供网络运行的详细情况。SLA是客户和网络服务商签署的关于网络QoS的正式合同,明确规定了所期望的服务质量的级别,其中包括所期望的服务项目和QoS参数。SNMP采集平台是流量异常监测系统的基础,负责远程数据的采集。本文主要描述了基于SLA流量异常监测系统的设计与实现的详细过程。