Performance comparison of multicast routing protocols based on NS-2

The electronic system in a comprehensive shipboard has a extremely wide bandwidth. It supports synchronized and asynchronous data transmission, multimedia correspondence, and videophone conferencing. In order to guarantee the security and correspondent real time of the communication, choosing a multicast routing protocol based on different applications is a key problem in terms of the complexity of the system. A simulation model was first designed for existing multicast routing protocols in NS-2 and analysis was performed on their corresponding application environments. The experiments proved that PIM-DM based on the shortest-path tree protocol is suitable for communication in the field of comprehensive shipboard. Further work that is necessary is also discussed.     

应用面向对象程序设计方法实现列车运行图绘制

介绍面向对象编程方法,阐述用其方法完成列车运行图的绘制过程,并且介绍列车运行图编制系统中所涉及的各种问题及解决方法.     

车辆安全检测和管理系统的设计与实现

分析海量数据传输和管理系统的功能,并针对系统特点提出了基于C/S和B/S混合结构的解决方案,最后介绍了系统的设计与实现.     

Real-time motion planning methods for autonomous on-road driving: State-of-the-art and future research directions

Currently autonomous or self-driving vehicles are at the heart of academia and industry research because of its multi-faceted advantages that includes improved safety, reduced congestion, lower emissions and greater mobility. Software is the key driving factor underpinning autonomy within which planning algorithms that are responsible for mission-critical decision making hold a significant position. While transporting passengers or goods from a given origin to a given destination, motion planning methods incorporate searching for a path to follow, avoiding obstacles and generating the best trajectory that ensures safety, comfort and efficiency. A range of different planning approaches have been proposed in the literature. The purpose of this paper is to review existing approaches and then compare and contrast different methods employed for the motion planning of autonomous on-road driving that consists of (1) finding a path, (2) searching for the safest manoeuvre and (3) determining the most feasible trajectory. Methods developed by researchers in each of these three levels exhibit varying levels of complexity and performance accuracy. This paper presents a critical evaluation of each of these methods, in terms of their advantages/disadvantages, inherent limitations, feasibility, optimality, handling of obstacles and testing operational environments.Based on a critical review of existing methods, research challenges to address current limitations are identified and future research directions are suggested so as to enhance the performance of planning algorithms at all three levels. Some promising areas of future focus have been identified as the use of vehicular communications (V2V and V2I) and the incorporation of transport engineering aspects in order to improve the look-ahead horizon of current sensing technologies that are essential for planning with the aim of reducing the total cost of driverless vehicles. This critical review on planning techniques presented in this paper, along with the associated discussions on their constraints and limitations, seek to assist researchers in accelerating development in the emerging field of autonomous vehicle research.     

基于损伤退化模型的钢筋混凝土梁式桥加固计算方法研究

为了客观反映材料退化、结构损伤、运营环境变化及结构工作状态改变等因素对桥梁承载能力的影响,分析了桥梁加固计算的特点,给出了基于损伤退化模型的钢筋混凝土梁式桥正截面及斜截面承载能力计算公式,提出了结构加固计算的一般步骤,并以工程实例给出了具体应用方法。     

航次租船中的留置权条款

主要讨论金康租约及其他主要租约中的留置权条款。许多航次租船合同中,都包含一个船东行使留置权条款,船东能否获得有效的留置权,是否能获得及时支付,却经常遇到争议。针对这一条款作简要分析,以期引起有关人员的重视。     

Forecasting petrol demand and assessing the impact of selective strategies to reduce fuel consumption

Abstract

The use of fossil fuels in transportation is an important topic as a result of growing concerns over global warming. Automobile petrol demand has been of particular interest to researchers and policy-makers, given that the automobile is a major contributor to the enhanced greenhouse effect. This paper forecasts Australia's automobile petrol demand up to the year 2020 based on the best performing forecasting model selected out of eight models. In order to establish ways to reduce the demand for petrol, and the consequent by-product of reducing the amount of greenhouse gas emissions, we have estimated the impact on CO₂ for several potential policy instruments, using Transportation and Environment Strategy Impact Simulator (an integrated transport, land use and environmental strategy impact simulation programme). We find that a carbon tax of AU$0.50/kg can reduce automobile kilometres by 5.9%, resulting in reduced demand for petrol and a reduction in CO₂ of 1.5%.     

关于C50结构砼的适用配比研究

对C50混凝土配合比设计中的设计方法、注意事项及施工中的控制重点提出一些看法.     

基于C30并行多处理器系统的设计与应用

介绍应用于某型声纳仿真测试仪的并行多处理系统，该系统以TMS320C30为基本处理单元，并具有较强的并行处理能力。给出仿真仪的硬件体系结构和软件开发方法，具有性价比高、开发周期短等优点。