基于驾驶行为和信息熵的道路交通安全风险预估

为了精准有效地进行交通事故预防预警，基于车辆OBD驾驶行为数据及信息熵理论，提出了城市道路交通安全风险预估方法。首先，分析异常驾驶行为高发位置与道路交通事故发生位置的关联性；其次，构建以道路交通安全熵为一级指标，急加速率、急减速率、急转弯率、超速率、高速空挡滑行率为二级指标的道路交通安全风险预估指标体系，提出了基于改进熵权法的道路交通安全熵计算方法；然后，基于密度聚类、K-means聚类提出了道路交通安全风险等级数确定方法，并基于K-means聚类建立了风险等级阈值计算方法。研究结果表明：异常驾驶行为高发位置与交通事故发生位置具有一致性；通过对log对数底数选择优化、二级指标零值处理、指标权重分段计算3个步骤改进的熵权法，可弥补log对数函数无法计算零值指标熵值的缺陷，避免指标权重为负、指标熵值与权重反映信息不一致的现象；两步聚类避免了孤立数据点对安全风险等级划分的影响。以重庆市4条城市道路（总长约38 km）进行实例验证后得出，道路交通安全熵与交通事故表征的道路交通安全状态趋势一致；道路交通安全风险等级可划分为高、低风险2级，道路交通安全熵优化阈值为0.042，最后，风险等级划分准确率为87.88%。研究成果可为道路交通安全风险点辨识、交通事故预防预警提供有效的技术支持。     

Route Selection for Railway Passengers: A Multi-objective Model and Optimization Algorithm

With an increased operating speed in Chinese railways in recent years, the number of passengers traveling by trains has been significantly increasing. The research issue is regarding how passengers select their routes when there are no direct trains. Previous studies have dealt with the route selection problem as a multi-objective optimization. The study began by setting up a transportation network which encompasses the departure and terminal stations along with important intermediate stations. Then, six key factors are analyzed and formulated using a multi-objective model, consisting of the train-running time, railway fare, transfer frequencies, distances between transfer stations, transfer interval time, and travel comfort. Furthermore, a two-phase algorithm is employed to solve the model. A rapid searching algorithm for feasible routes based on the train timetable is established, then the weight vector is assigned by introducing the information entropy to obtain satisfied routes. In the end, the two-phase algorithm is tested respectively for railway passengers from Lanzhou to Beijing (with direct trains) and from Lanzhou to Changchun (without direct trains), and the results show that the proposed model and solution algorithm are efficient for obtaining satisfactory routes.     

CAD与CAPP信息共享研究

如何实现CAPP与CAD之间的信息共享，无缝连接，一直是CAPP系统开发过程中的一个难点，对该问题进行了研究与探索，介绍了一种如何获取CAD图纸界面上零件总体信息及将CAPP系统处理后的数据库信息写到CAD图纸界面上的方法。     

船舶涂装污染及处理技术

文章分析了船舶涂装污染物的来源、成分和性质，并针对性的介绍了科学、先进、具有较强使用性和可操作性的处理方法。     

机车质量信息管理系统设计与开发

从铁路局角度出发，针对机车质量信息管理系统的研究开发，提出系统的建设思路和原则，并围绕系统的构成、现场流程控制及基础技术数据处理，对系统的先进性、安全性、易用性、可扩展性，以及可维护性原则等方面加以论述。机车质量信息管理系统的建立，可以提高机务段检修管理水平，为机车检修从计划修向状态修转变创造条件。     

搜索引擎相关技术研究概述

主要介绍了搜索引擎的概念、分类和主要工作原理,并详细介绍了目前该领域所涉及的关键技术及相应的主要研究方向,最后指出了目前的搜索引擎存在的问题,并提出了一种改进的研究方向.     

The impact of route guidance,departure time advice and alternative routes on door-to-door travel time reliability: Two data-driven assessment methods

ABSTRACT

Conventional travel time reliability assessment has evolved from road segments to the route level. However, a connection between origin and destination usually consists of multiple routes, thereby providing the option to choose. Having alternatives can compensate for the deterioration of a single route; therefore, this study assesses the reliability and quality of the aggregate of the route set of an origin-destination (OD) pair. This paper proposes two aggregation methods for analyzing the reliability of travel times on the OD level: 1) an adapted Logsum method and 2) a route choice model. The first method analyzes reliability from a network perspective and the second method is based on the reliability as perceived by a traveler choosing his route from the available alternatives. A case study using detailed data on actual travel times illustrates both methods and shows the impact of having variable departure times and the impact of information strategies on travel time reliability.     

船舶涂装污染处理技术分析

分析船舶涂装污染物的来源、成分和性质,并针对性地介绍科学、先进,具有较强实用性和可操作性的处理方法。     

Spatial Information Infrastructure for Integrated Coastal and Ocean Management in Canada

Access to current, comprehensive, and reliable spatial information is necessary for informed decision making in integrated coastal and ocean management. This need is being met through development of a marine spatial information infrastructure that encompasses both technological and institutional responses. This article traces Canada's experience in developing a marine spatial information infrastructure over the last 30 years starting with the compilation of coastal atlases, through the development of geographic information systems, to remote data acquisition instruments and Web mapping portals. Because of the plethora of initiatives, it has been essential to be selected and limit the number and choice of examples. The institutional response has lagged behind that of technological innovation and hinges on understanding users’ needs and decision support drivers, sustainability of institutional and individual champions, and, above all, cooperation and collaboration among the broad community of practice.     

综合数据处理系统在津滨轻轨中的应用

结合综合数据处理系统在津滨轻轨工程中的应用实例，提出城市轻轨项目信息集成与综合处理的解决方案，并进一步探讨系统在设备综合维护管理方面的扩展应用。