基于RFCS的城轨列车无线视频监控统切换机制

针对城轨列车跨越多个无线接入点AP高速运行时存在切换延迟的问题,在对城轨列车无线视频监控系统研究的基础上,提出一种RFCS（RF channel switched）机制,在这种机制下,无线接入点AP按照预定的顺序周期性的改变RF信道来防止相邻AP信道的重叠,从而减小了切换延迟,增大了网络吞吐量,最终实现无缝切换.并用NS2仿真软件对该方案进行仿真,与传统的切换过程相比,该方案明显减小了切换时延,保证了城轨列车无线视频监控系统的实时性.     

基于灰色理论的民用汽车运力动员能力评估

在当前军民融合式发展的大趋势下,汽车运力动员作为民用运力动员的一个组成部分,在现代战争中发挥着重要作用。提出一种基于灰色理论的评估方法,通过分析民用汽车运力动员体系的构成要素,构建动员能力评估指标体系,客观评估动员能力,并依据结果提出相应的改进建议。可为加强民用汽车动员能力建设提供一定的参考。     

燃料电池城市客车用储氢瓶有限元分析和疲劳寿命分析

用有限元法对燃料电池城市客车用储氢瓶进行了预紧导致的残余应力应变分析和充放气条件下的表面应力应变分析,通过与实测结果进行对比可知,二者基本吻合,说明有限元模型分析结果可信。进行储氢瓶疲劳寿命分析时,先得出铝内衬零件S-N曲线,再将铝内衬筒体中部的多轴交变应力转换为等效的对称循环条件下的单轴交变应力,最后根据该S-N曲线得出储氢瓶疲劳寿命为2.57×105次循环,与实际情况相符。     

用户均衡条件下3类停车设施收费定价模型

为了模拟多类停车设施运营(收费定价)竞争以及出行者的反馈行为,建立了基于用户均衡条件的路外、路内停车场和停车换乘设施等3类停车设施的收费定价模型。上层优化模型模拟停车运营者以利润最大为目标的停车费定价决策,下层用户均衡条件描述出行者以个人出行成本最小为原则的旅行选择行为,包括方式、路径和停车设施的选择。采用基于灵敏度分析的算法来求解该非线性规划问题。设计算例对模型和算法的有效性进行验证,结果表明:考虑多类停车设施运营竞争对停车收费定价最优解有显著影响,并且可能导致较低的停车收费水平和较好的交通需求管理效果,如人均出行的交通拥挤成本降低,停车换乘方式分担率提高等。     

船厂门机变幅系统的优化设计

门机在修造船厂应用十分广泛,本文以D2545型门机为研究对象,从影响整机使用性能和成本的变幅系统入手,分别计算和比较水平性、不平衡力矩、臂架结构和变幅机构功率这几个关键技术参数,说明优化方案对成本和使用性能的影响。     

价值工程在煤炭港口企业设备运行管理中的应用研究

介绍了价值工程的基本理论和方法;结合煤炭港口企业设备运行管理的特点,以2012年吞吐量3000万t的某煤码头为例,阐述了价值工程在煤炭港口企业设备运行管理中的应用方法和主要步骤。     

常规潜艇燃料电池AIP系统氢源技术应用研究

为了解决常规潜艇燃料电池AIP系统在密闭、狭小空间内安全、可靠、高效存储或制备氢气的问题,根据潜艇的特点以及作战需求,在简要分析工业上常用储氢和制氢技术的基础上,综合比较了各种氢源技术方案的装艇优缺点,提出了一种适用于常规潜艇燃料电池系统的氢源技术——NaBH4水解制氢.     

Measuring the Cost Effectiveness of Multimode Bus Transit in the Presence of Accident Risks

Abstract

This study employs the directional graph distance function and the multiactivity data envelopment analysis (DEA) approach, which incorporates both desirable and undesirable outputs, in order to provide a more complete representation of the multimode bus production technology from which environmentally and risk-sensitive cost effectiveness measures can be generated. We treat accident cost as the risky output in the sense that we wish to increase desirable outputs and decrease risky output and inputs. The approach is applied to the problem of measuring the cost effectiveness of 24 bus companies in Taiwan. An empirical illustration suggests that the overall cost effectiveness rankings turn out to be very sensitive to whether or not the graph multiactivity DEA approach is adopted. This implies that the conventional DEA cost effectiveness measure may be seriously misleading if it ignores the cost effectiveness of organizations that carry out various activities whilst sharing common resources.     

Evaluation of the Transferability of Incident Detection Algorithms Developed for Singapore Expressways

ABSTRACT

Two new detection algorithms, single-station DV (dual-variable) and dual-station CODE (COmbined Detector Evaluation) were developed earlier using 160 incidents collected along Singapore's Central Expressway (CTE). The transferability of these CTE-developed algorithms is assessed, as a case study, using 100 incidents collected from the Tullamarine Freeway and South Eastern Freeway in Melbourne, Australia. The investigation covers the differences in traffic detector systems (loop detectors versus video-based), road geometry and behaviour between drivers in Singapore and Australia. The re-calibrated application of these algorithms to freeways in Melbourne yielded a reasonably good detection performance as well as satisfying the average expected performances of seven traffic management centres surveyed in the USA. The results suggested that the detection logic of the algorithms developed for CTE possessed reasonably good transferability and are also suitable for receiving traffic inputs from video-based detectors as well as from loop detectors.     

船舶电力系统静态安全分析概述

船舶电力系统日趋复杂化,船员已难以通过经验来判断电力系统的安全运行状态.在陆地电网静态安全分析的基础上,针对船舶电力系统的特点,提出船舶电力系统静态安全分析的概念,同时给出适合船舶电力系统预想事故的危害度指标和安全裕度指标,弥补了船舶电力系统在这方面的空白.