An optimization framework for workplace charging strategies

The workplace charging (WPC) has been recently recognized as the most important secondary charging point next to residential charging for plug-in electric vehicles (PEVs). The current WPC practice is spontaneous and grants every PEV a designated charger, which may not be practical or economic when there are a large number of PEVs present at workplace. This study is the first research undertaken that develops an optimization framework for WPC strategies to satisfy all charging demand while explicitly addressing different eligible levels of charging technology and employees’ demographic distributions. The optimization model is to minimize the lifetime cost of equipment, installations, and operations, and is formulated as an integer program. We demonstrate the applicability of the model using numerical examples based on national average data. The results indicate that the proposed optimization model can reduce the total cost of running a WPC system by up to 70% compared to the current practice. The WPC strategies are sensitive to the time windows and installation costs, and dominated by the PEV population size. The WPC has also been identified as an alternative sustainable transportation program to the public transit subsidy programs for both economic and environmental advantages.     

道路交通事故多发点鉴别

介绍了事故多发点的分析方法，建立了事故多发点判别模型，并给出了其算法，根据中国交通流的特点，开发了事故多发点数据库，使事故多发点的鉴别工作能够快速进行。     

山区公路事故多发段道路条件分析与防治对策

针对山区公路交通事故的严重性,从山区公路道路条件的角度,对山区公路事故多发段道路环境中存在的主要隐患以及这些隐患如何导致了交通事故的发生进行了分析,并提出了对事故多发段进行改造的原则和防治对策。     

The role of paratransit: some reflections based on the experience of residents’ coach services in Hong Kong

Paratransit refers to urban transport services “somewhere between private passenger transport and conventional public transport in terms of cost and quality of service” [Rimmer (1980), Paratransit: A commentary. Environ. Plan. A 12, 937–944]. Since the 1980s, a new form of paratransit—residents’ coach, which provides exclusive transport services to residents living in private housing estates—has emerged in Hong Kong. What was the background underlying the emergence and subsequent growth of residents’ coach services? Also, what was the role of residents’ coach in the public transport system of Hong Kong? With the completion of more railway extensions, should residents’ coach services be replaced? If so, what are the potential impacts on people’s life? This paper addresses the above research questions through a large-scale questionnaire survey that examined not only people’s modal choice but also their residential choice, socio-economic background and attitudes. The findings suggest that transport policy makers should pay more attention to examine new forms of paratransit and the ways of integrating them into the overall public transport system, both spatially and temporally. It is only through the development of an efficient and multi-modal transport system can the maximum potential of paratransit in filling the transport gap between conventional mass transit and private cars be realized.     

事故多发点鉴别及其成因分析

对比分析了事故多发点鉴别及其成因方法,归纳总结了各种方法的优缺点及适用条件。提出了基于BP神经网络的高速公路事故多发点鉴别方法,并应用实际高速公路交通事故数据,标定了网络的权值矩阵和偏置向量,该方法能有效解决矩阵法中人为确定边界的不足。针对事故多发点的突出事故诱导因素问题,提出了基于动态模糊聚类的多发点成因分析方法,该方法能将众多的事故诱导因素聚类为从主要原因到隐患原因等4个类别,进而得出较客观的成因分类结果。     

From traces to trajectories: How well can we guess activity locations from mobile phone traces?

Passively generated mobile phone dataset is emerging as a new data source for research in human mobility patterns. Information on individuals’ trajectories is not directly available from such data; they must be inferred. Many questions remain in terms how well we can capture human mobility patterns from these datasets. Only one study has compared the results from a mobile phone dataset to those from the National Household Travel Survey (NHTS), though the comparison is on two different populations and samples. This study is a very first attempt that develops a procedure to generate a simulated mobile phone dataset containing the ground truth information. This procedure can be used by other researchers and practitioners who are interested in using mobile phone data and want to formally evaluate the effectiveness of an algorithm.To identify activity locations from mobile phone traces, we develop an ensemble of methods: a model-based clustering method to identify clusters, a logistic regression model to distinguish between activity and travel clusters, and a set of behavior-based algorithms to detect types of locations visited. We show that the distribution of the activity locations identified from the simulated mobile phone dataset resembles the ground truth better than the existing studies. For home locations, 70% and 97% of identified homes are within 100 and 1000 m from the truth, respectively. For work places, 65% and 86% of the identified work places are within 100 and 1000 m from the true ones, respectively. These results point to the possibility of using these passively generated mobile phone datasets to supplement or even replace household travel surveys in transportation planning in the future.     

Exploring electric vehicle charging patterns: Mixed usage of charging infrastructure

This paper examines the charging behavior of 7,979 plug-in electric vehicle (PEV) owners in California. The study investigates where people charge be it at home, at work, or at public location, and the level of charging they use including level 1, level 2, or DC fast charging. While plug-in behavior can differ among PEV owners based on their travel patterns, preferences, and access to infrastructure studies often make generalizations about charging behavior. In this study, we explore differences in charging behavior among different types of PEV owners based on their use of charging locations and levels, we then identify factors associated with PEV owner’s choice of charging location and charging level. We identified socio-demographic (gender and age), vehicle characteristics, commute behavior, and workplace charging availability as significant factors related to the choice of charging location.     

路堤工程信息化施工测点的优化布置

引入了系统论中灵敏度分析方法 ,提出了测点优化设置的概念 ,对一路堤工程进行了位移和孔压对土性参数的灵敏度分析 ,并根据分析结果优化设置了量测点位置。该方法对路堤工程信息化施工测点的优化布置很有指导意义     

道路事故多发地点的鉴别与整治

预防交通事故,降低交通事故死亡率,已成为全社会面临的一项十分紧迫的任务。深入分析交通事故的成因,研究事故多发地点的鉴别方法和整治措施尤显重要。通过对贵阳市事故资料调查与统计分析,运用事故累计频率法鉴别事故多发地点,提出切实可行的整治措施,降低交通事故的发生,改善道路的安全水平。     

The influence of workplace environment on lung function of shopkeepers working near National Highway in Jalgaon: A note

The inferior ambient air quality was observed near highway passing through Jalgaon urban center. Among the pollutants critical level of particulates are observed at the roadside during May 2003 to April 2004. The shopkeepers working at the highway sides are at high risk of exposure to the air pollution caused by heavy highway traffic. The lung function test of the shopkeepers shows significant decrease in forced vital capacity, forced expiratory volume in one second and peak expiratory flow rate. The regular periodic health checkup and use of nose mask will protect the health of shopkeepers working near National Highway passing through Jalgaon urban center.