Development of behavioral context addressable loggers in the shell for travel-activity analysis

This study attempts to develop a small, portable travel-activity measuring instrument that requires no entry from respondents. Conventional surveys have collected identification information such as facility type, transport mode, and activity content through the operation of instruments, questionnaires, etc. However, these complicated surveys burden the respondents and rely on their memory, often leading to recording omissions or incorrect records. We propose a method for estimating behavioral contexts using BCALs (Behavioral Context Addressable Loggers in the Shell), a wearable, behavioral context information-measuring instrument, for re-estimating label information such as facility type and transport mode from ecological and environmental sensors based on learning models. The numerical values observed by these sensors differed greatly among locations or means of transportation, revealing the high possibility of automatic identification of locations and means of transportation using BCALs.     

基于航海模拟器实施雷达定位训练的方法探究

文章基于TRANSAS航海模拟器,运用其内置电子海图进行纸质海图的制作,解决雷达定位的培训和训练问题,经过实践,完全满足要求。     

对我国现行的海员证管理的探讨

现行《中华人民共和国海员证管理办法》颁布距今已近二十年,原来的规定中已有一部分不能适应现在的政治、经济形势和社会的发展。笔者参考国内相关的法律、法规和国际公约,并结合多年从事海员证管理工作的积累,从海员证的属性、申请、颁发到使用,对现行的海员证管理进行探讨。     

Evaluation of a cellular phone-based system for measurements of traffic speeds and travel times: A case study from Israel

The purpose of this paper is to examine the performance of a new operational system for measuring traffic speeds and travel times which is based on information from a cellular phone service provider. Cellular measurements are compared with those obtained by dual magnetic loop detectors. The comparison uses data for a busy 14 km freeway with 10 interchanges, in both directions, during January–March of 2005. The dataset contains 1 284 587 valid loop detector speed measurements and 440 331 valid measurements from the cellular system, each measurement referring to a 5 min interval. During one week in this period, 25 floating car measurements were conducted as additional comparison observations. The analyses include visual, graphical, and statistical techniques; focusing in particular on comparisons of speed patterns in the time–space domain. The main finding is that there is a good match between the two measurement methods, indicating that the cellular phone-based system can be useful for various practical applications such as advanced traveler information systems and evaluating system performance for modeling and planning.     

Multi-step prediction of experienced travel times using agent-based modeling

This paper develops an agent-based modeling approach to predict multi-step ahead experienced travel times using real-time and historical spatiotemporal traffic data. At the microscopic level, each agent represents an expert in a decision-making system. Each expert predicts the travel time for each time interval according to experiences from a historical dataset. A set of agent interactions is developed to preserve agents that correspond to traffic patterns similar to the real-time measurements and replace invalid agents or agents associated with negligible weights with new agents. Consequently, the aggregation of each agent’s recommendation (predicted travel time with associated weight) provides a macroscopic level of output, namely the predicted travel time distribution. Probe vehicle data from a 95-mile freeway stretch along I-64 and I-264 are used to test different predictors. The results show that the agent-based modeling approach produces the least prediction error compared to other state-of-the-practice and state-of-the-art methods (instantaneous travel time, historical average and k-nearest neighbor), and maintains less than a 9% prediction error for trip departures up to 60 min into the future for a two-hour trip. Moreover, the confidence boundaries of the predicted travel times demonstrate that the proposed approach also provides high accuracy in predicting travel time confidence intervals. Finally, the proposed approach does not require offline training thus making it easily transferable to other locations and the fast algorithm computation allows the proposed approach to be implemented in real-time applications in Traffic Management Centers.     

交通移动采集技术及其适用性分析

交通移动采集技术是一种先进的交通信息采集技术,目前在国外很多城市都进行了广泛的实验和应用。本文在分析常规交通采集技术的不足和交通移动采集技术特点的基础上,结合中国城市交通的特点,分析认为交通移动采集技术同样适合于国内大部分城市,并且有着广泛的应用前景。此外本文还将交通移动采集技术分为主动测试车技术和被动探测车技术。最后以中山市公交车采集的数据作为被动探测车数据,简单探讨了交通移动采集数据的分析和处理方法。     

Simple analytical models for estimating the queue lengths from probe vehicles at traffic signals

As mobile traffic sensor technology gets more attention, mathematical models are being developed that utilize this new data type in various intelligent transportation systems applications. This study introduces simple analytical estimation models for queue lengths from tracked or probe vehicles at traffic signals using stochastic modeling approach. Developed models estimate cycle-to-cycle queue lengths by using primary parameters such as arrival rate, probe vehicle proportions, and signal phase durations. Valuable probability distributions and moment generating functions for probe information types are formulated. Fully analytical closed-form expressions are given for the case ignoring the overflow queue and approximation models are presented for the overflow case. Derived models are compared with the results from VISSIM-microscopic simulation. Analytical steady-state and cycle-to-cycle estimation errors are also derived. Numerical examples are shown for the errors of these estimators that change with probe vehicle market penetration levels, arrival rates, and volume-to-capacity ratios.     

新经济组织新社会组织党建工作创新机制探索

"两新"组织是当前党建工作所面临的新的时代课题。文章介绍了以昆山为代表的苏南地区党组织大胆探索并构建的"两新"组织党建工作创新机制,指出在新的时代条件下应以建设和谐企业的全新理念统领"两新"组织党建工作的全局,探求符合"两新"组织自身特点和发展规律的新方式、新方法,构建"两新"组织党建中新的运行机制。     

A discounted recursive logit model for dynamic gridlock network analysis

Emerging sensing technologies such as probe vehicles equipped with Global Positioning System (GPS) devices on board provide us real-time vehicle trajectories. They are helpful for the understanding of the cases that are significant but difficult to observe because of the infrequency, such as gridlock networks. On the premise of this type of emerging technology, this paper propose a sequential route choice model that describes route choice behavior, both in ordinary networks, where drivers acquire spatial knowledge of networks through their experiences, and in extraordinary networks, which are situations that drivers rarely experience, and applicable to real-time traffic simulations. In extraordinary networks, drivers do not have any experience or appropriate information. In such a context, drivers have little spatial knowledge of networks and choose routes based on dynamic decision making, which is sequential and somewhat forward-looking. In order to model these decision-making dynamics, we propose a discounted recursive logit model, which is a sequential route choice model with the discount factor of expected future utility. Through illustrative examples, we show that the discount factor reflects drivers’ decision-making dynamics, and myopic decisions can confound the network congestion level. We also estimate the parameters of the proposed model using a probe taxis’ trajectory data collected on March 4, 2011 and on March 11, 2011, when the Great East Japan Earthquake occurred in the Tokyo Metropolitan area. The results show that the discount factor has a lower value in gridlock networks than in ordinary networks.     

Probe vehicle-based traffic state estimation method with spacing information and conservation law

This paper proposes a method of estimating a traffic state based on probe vehicle data that contain spacing and position of probe vehicles. The probe vehicles were assumed to observe spacing by utilizing an advanced driver assistance system, that has been implemented in practice and is expected to spread in the near future. The proposed method relies on the conservation law of the traffic flow but is independent of a fundamental diagram. The conservation law is utilized for reasonable aggregation of the spacing data to acquire the traffic state, i.e., a flow, density and speed. Its independence from a fundamental diagram means that the proposed method does not require predetermined nor exogenous assumptions with regard to the traffic flow model parameters. The proposed method was validated through a simulation experiment under ideal conditions and a field experiment conducted under actual traffic conditions; and empirical characteristics of the proposed method were investigated.