Discrete dynamic models for freeway incident detection systems

This paper considers the problem of freeway incident detection within the general framework of computer‐based freeway surveillance and control. A new approach to the detection of freeway traffic incidents is presented based on a discrete‐time stochastic model of the form ARIMA (0, 1, 3) that describes the dynamics of traffic occupancy observations. This approach utilizes real‐time estimates of the variability in traffic occupancies as detection thresholds, thus eliminating the need for threshold calibration and lessening the problem of false‐alarms. Because the moving average parameters of the ARIMA (0, 1, 3) model change over time, these parameters can be updated occasionally. The performance of the developed detection algorithm has been evaluated in terms of detection rate, false‐alarm rate, and average time‐lag to detection, using a total of 1692 minutes of occupancy observations recorded during 50 representative traffic incidents.     

Characterization and comparison of traffic flow on reversible roadways

Reversible traffic operations have become an increasingly popular strategy for mitigating traffic congestion associated with the directionally unbalanced traffic flows that are a routine part of peak commute periods, planned special events, and emergency evacuations. It is interesting that despite its widespread and long‐term use, relatively little is known about the operational characteristics of this form of operation. For example, the capacity of a reversed lane has been estimated by some to be equal to that of a normal lane while others have theorized it to be half of this value. Without accurate estimates of reversible lane performance it is not possible to confidently gauge the benefits of reversible roadways or model them using traffic simulation. This paper presents the results of a study to measure and evaluate the speed and flow characteristics of reverse‐flow traffic streams by comparing them under various operating conditions and locations. It was found that, contrary to some opinions, the flow characteristics of reverse‐flowing lanes were generally similar to normally flowing lanes under a variety of traffic volume, time‐of‐day, location, and type‐of‐use conditions. The study also revealed that drivers will readily use reversible lanes without diminished operating speeds, particularly as volumes increase. Copyright © 2010 John Wiley & Sons, Ltd.     

项目、课程、竞赛:“三三制”机电人才培养模式探索

本文针对地方高校在新工科改革的作用,提出项目、课程、竞赛相结合的"三三制"机电人才培养模式,积极推动专业人才融入当地工业与经济的发展,为机电专业的人才培养提供了新的参考。     

基于软交换技术的VoIP在城轨公务电话系统中的应用研究

研究比选城轨公务电话系统典型构建方案,提出将基于软交换的VoIP技术应用在城轨公务电话领域,对该技术在城轨公务电话系统中应用的可行性及具体的构建方案展开深入研究。     

郑西客运专线四电系统集成的安全性分析

四电系统集成的安全性是实现高速铁路高效可靠运营的基础和保证。以郑西客运专线四电系统为例,建立系统评价指标体系,利用改进AHP确定各个评价指标的权重向量和隶属度矩阵,并结合综合安全水平模糊综合评价法对郑西客运专线四电系统集成进行定性描述以及定量分析,分析结果表明郑西客运专线四电系统集成的安全性水平较高。     

Simulation based population synthesis

Microsimulation of urban systems evolution requires synthetic population as a key input. Currently, the focus is on treating synthesis as a fitting problem and thus various techniques have been developed, including Iterative Proportional Fitting (IPF) and Combinatorial Optimization based techniques. The key shortcomings of these procedures include: (a) fitting of one contingency table, while there may be other solutions matching the available data (b) due to cloning rather than true synthesis of the population, losing the heterogeneity that may not have been captured in the microdata (c) over reliance on the accuracy of the data to determine the cloning weights (d) poor scalability with respect to the increase in number of attributes of the synthesized agents. In order to overcome these shortcomings, we propose a Markov Chain Monte Carlo (MCMC) simulation based approach. Partial views of the joint distribution of agent’s attributes that are available from various data sources can be used to simulate draws from the original distribution. The real population from Swiss census is used to compare the performance of simulation based synthesis with the standard IPF. The standard root mean square error statistics indicated that even the worst case simulation based synthesis (SRMSE = 0.35) outperformed the best case IPF synthesis (SRMSE = 0.64). We also used this methodology to generate the synthetic population for Brussels, Belgium where the data availability was highly limited.     

《客车类型划分及等级评定》新旧标准对此

通过JT／T325—2010与JT／T325—2006的对比,梳理出修改的主要内容,帮助有关人员进一步熟悉新标准。     

海事动态监管系统需求分析与技术实现

根据浙江海事局辖区的具体情况分析我国的经济发展和安全趋势,指出传统海事监管手段存在的问题并进行深入的分析,从稳定性、功能性、性能和扩展性四方面提出新型海事动态监管手段的建设目标,并介绍了实现此目标所需要使用的关键技术,如SOA 架构和适配器模式、框架和插件技术、分布式系统和空间索引技术,最后对海事动态监管系统的未来进行展望,为海事动态监管系统的建设提供了一套完整的技术解决方案。     

有限域上线性方程组的相变现象

对于含有n个未知数t个方程的线性方程组,各种实验显示随着参数r（方程个数／未知数个数）的变化,会发生从有解到无解的相变现象。研究工随机产生的有限域F上的k-线性方程组（每个线性方程中只含有k个变量）的相变现象,给出了k-线性方程组相变点的上界和下界。     

船舶电力系统中基于BFS的开关动作排序控制方法

为了解决现有船舶电网保护方法难以达到复杂网络对保护选择性要求的弱势,提出基于广度优先搜索法(Breadth First Search)的开关动作排序法。该方法通过控制开关的延时长短,让上下级开关的时间设定值相互配合,达到保护选择性要求。最后用3个实例对比原有方法证明了新方法的优势和有效性。