Dynamic routing-and-inventory problems: a review

The paper presents a review of the available literature on a class of problems denoted as dynamic routing-and-inventory (DRAl) problems. They are characterized by the simultaneous relevance of routing and of inventory issues in a dynamic environment, within the framework of distribution logistics. A classification scheme is first proposed for these problems. Then the results obtained in this area are summarized. Finally, the papers available in the literature are clustered and discussed according to the proposed scheme.     

VAN总线技术及应用

阐述了VAN总线协议及其技术特点,描述了VAN的物理层和数据链层。以实例说明VAN总线载波监听多路访问/冲突检测技术和E-Manchester编码。介绍了3类通信模块、报文格式及其各部分的组成及功能。对通信中5种条件下的通信帧进行了说明,最后介绍了VAN总线的两种典型应用形式和发展趋势。     

基于内燃机车柴油机内漏检测仪的网络化改造

介绍了在数字化改造过程中,采用廉价的MSC5 1单片机和RTL80 19AS实现柴油机内漏检测仪的网络化改造。并采用C5 1高级编程语言实现TCP/IP协议,使检测仪器的数据向以太网传递     

基于Softswitch的呼叫控制中心体系构建探讨

介绍了Softswitch的概念和当前呼叫中心技术存在的问题,提出基于Softswitch的呼叫控制中心构建方案及相关技术.     

Floating car based travel times for city logistics

City logistics routing requires time-dependent travel times for each network link. We rely on the concept of Floating Car Data (FCD) to develop and provide such travel times. Different levels of aggregation in the determination of time-dependent travel times from a database of historical FCD are presented and evaluated with regard to routing quality. Furthermore, a Data Mining approach is introduced, allowing for a substantial reduction of the volume of input data required for city logistics routing. The different approaches are investigated and evaluated by a huge amount of FCD collected for the urban area of Stuttgart, Germany. The results show that the Data Mining approach enables efficient provision of time-dependent travel times without a significant loss of routing quality for city logistics applications.     

TXJK型驼峰信号溜放进路自动控制系统

介绍ＴＸＪＫ驼峰信号溜放进路自动控制系统的结构，功能及特点。     

Windows CE下的网络应用研究

嵌入式WindowsCE最大的优点在于:界面的通用性、用户容易接收、并可以将Windows通用操作系统下的应用程序移植到嵌入式应用系统中.关于Windows CE的研究文献有许多,但是,缺少从构建平台到网络应用的系统分析.从网络应用出发,深入研究在WindowsCE下如何实现TCPflP协议,这对嵌入式网络应用意义重大.     

A dynamic behavioural traffic assignment model with strategic agents

Foresee traffic conditions and demand is a major issue nowadays that is very often approached using simulation tools. The aim of this work is to propose an innovative strategy to tackle such problem, relying on the presentation and analysis of a behavioural dynamic traffic assignment.The proposal relies on the assumption that travellers take routing policies rather than paths, leading us to introduce the possibility for each simulated agent to apply, in real time, a strategy allowing him to possibly re-route his path depending on the perceived local traffic conditions, jam and/or time already spent in his journey.The re-routing process allows the agents to directly react to any change in the road network. For the sake of simplicity, the agents’ strategy is modelled with a simple neural network whose parameters are determined during a preliminary training stage. The inputs of such neural network read the local information about the route network and the output gives the action to undertake: stay on the same path or modify it. As the agents use only local information, the overall network topology does not really matter, thus the strategy is able to cope with large and not previously explored networks.Numerical experiments are performed on various scenarios containing different proportions of trained strategic agents, agents with random strategies and non strategic agents, to test the robustness and adaptability to new environments and varying network conditions. The methodology is also compared against existing approaches and real world data. The outcome of the experiments suggest that this work-in-progress already produces encouraging results in terms of accuracy and computational efficiency. This indicates that the proposed approach has the potential to provide better tools to investigate and forecast drivers’ choice behaviours. Eventually these tools can improve the delivery and efficiency of traffic information to the drivers.     

Coordinated online in-vehicle routing balancing user optimality and system optimality through information perturbation

The inconsistence between system optimality and user optimality represents one of the key difficulties on network traffic congestion control. The advanced connected vehicle systems, enabling smart vehicles to possess/exchange real-time information and conduct portable computation, provide new opportunities to address this challenge. Motivated by this view, this study proposes a coordinated online in-vehicle routing mechanism with intentional information provision perturbation (CRM-IP), which seeks to shape individual vehicles online routing decisions so that user optimality and system optimality are balanced, by exploiting bounded rationality of the users. The proposed CRM-IP is modeled as a pure strategy atomic routing game, and implemented by a sequentially updating distributed algorithm. The mathematical analysis is conducted to quantify the absolute gain of system optimality corresponding to the loss of user optimality resulting from a given level of the information perturbation in the worst case so that the efficiency of the information perturbation can be evaluated. Furthermore, numerical experiments conducted based on City of Sioux Falls network investigate the average effects of the CRM-IP on system optimality and user optimality under various network traffic conditions, comparing to the CRM developed by Du et al. (in press). The results indicate that the improvement of system optimality and the reduction of individual vehicles’ travel time from the CRM is more significant when the network traffic is under an mild congestion state, such as under the levels of service (LOS’s) C, D, and E, rather than under extremely sparse or congested states, such as under LOS’s A and B, or F. Moreover, higher level of information perturbation benefits system optimality more, but the marginal effect decreases after the perturbation reaching certain level, such as $\lambda =0.1$ in this case study. In addition, a portion of vehicles may sacrifice user optimality due to the information perturbation, but the extent of the sacrifice is not significant, even though it increases with the information perturbation level. Hence, a small information perturbation is recommended to achieve an efficient network traffic control through the CRM-IP. Overall, this study proposes the CRM-IP as an efficient routing mechanism, which has a great potential to guide the routing decisions of individual vehicles so that their collective behavior improve network performance in both system optimality and user optimality.     

无线局域网高效地址自动分配协议

在无线局域网(MANET-Mobile Ad Hoc Networks)中IP地址如何无冲突的分配一直是一个重要的论题。本文将使用聚集自动分配和有效地址选择给出一个高效的分配方案。无线局域网是由一系列平等的主机所构成,我们需要一个IP地址自动分配协议来对这些移动的主机进行控制,而在该协议制定中很好的考虑到这一特性。