大众捷运不断电系统的可用度及可靠度分析

分析单一组件的历时可用度行为,探讨对数常态分布可靠度(中位数tmed以及误差因子EF)和指数分布维修度(平均维修时间MTTR)对其可用度的影响,得出数值分析结果:在固定稳态可用度ASS以及平均维修时间MTTR的情况下,中位数tmed越小(或是误差因子EF越大)的组件历时可用度越早单调下降且下降量越大,越晚回弹至其稳态可用度;在固定稳态可用度ASS以及误差因子EF的情况下,具有越大平均维修时间MTTR的组件历时可用度越晚单调下降但下降量不变,也越晚回弹至其稳态可用度.建立不断电系统可用度以及可靠度的分析模式,探讨正常供电、电池备援以及旁通供电3种不同模式对整体可用度以及可靠度的贡献程度,得出数值分析结果:正常供电模式贡献了绝大部分的整体不断电可用度;不考虑维修作业能力,整体不断电系统的可靠度参数MTTF为1184301h.     

Determining the Monetary Value of Quality Attributes in Freight Transportation Using a Stated Preference Approach

It is commonly accepted that the modal choice of a shipper is influenced not only by the pure economic attributes of transportation – time and cost – but also by more qualitative factors. These quality attributes relate to frequency, reliability, flexibility, transport duration and risk of loss or damage; they are usually difficult to quantify in monetary terms. Different techniques exist that help to understand better how these different quality attributes of freight transportation influence modal choice. In this paper we apply a stated preference design. Using real business data, the aim is then to derive partial utility functions that allow us to calculate monetary values for these different quality attributes.     

手写输入改变HMI设计

手写输入识别技术通过电容式触摸传感器与先进手写识别软件的结合,为驾乘人员提供了另一种操控车载系统的方式。该技术能够识别各种手写字符,包括拉丁字母和各种亚洲文字,所有这些文字输入都通过手指在触摸屏上书写而完成。汽车已经成为人们日常生活不可或缺的部分。然而,日益拥堵的交通,各种驾驶限制和严苛的法规要求,让驾驶生活变得不再愉悦和轻松。身处现代社会中,人们对于移动互联的要求越来越高,消费者希望无论身处何地都能与外界取得联络。     

康明斯董事会喜迎新成员

2008年2月14日，康明斯公司宣布，前美国证券交易委员会（SEC）首席会计师、现任Kalorama咨询公司（Kalorama Partners LLC）执行董事罗伯特赫德曼成为康明斯董事会的第十名成员，负责领导董事会旗下的审计、财务、技术和环境政策委员会。     

Importance of traveler attitudes in the choice of public transportation to work: findings from the Regional Transportation Authority Attitudinal Survey

The commute mode choice decision is one of the most fundamental aspects of daily travel. Although initial research in this area was limited to explaining mode choice behavior as a function of traveler socioeconomics, travel times, and costs, subsequent studies have included the effect of traveler attitudes and perceptions. This paper extends the existing body of literature by examining public transit choice in the Chicago area. Data from a recent Attitudinal Survey conducted by the Regional Transportation Authority (RTA) in Northeastern Illinois were used to pursue three major steps. First, a factor analysis methodology was used to condense scores on 23 statements related to daily travel into six factors. Second, the factor scores on these six dimensions were used in conjunction with traveler socioeconomics, travel times, and costs to estimate a binary logistic regression of public transit choice. Third, elasticities of transit choice to the six factors were computed, and the factors were ranked in decreasing order of these elasticities. The analysis provided two major findings. First, from a statistical standpoint, the attitudinal factors improved the intuitiveness and goodness-of-fit of the model. Second, from a policy standpoint, the analysis indicated the importance of word-of-mouth publicity in attracting new riders, as well as the need for a marketing message that emphasizes the lower stress level and better commute time productivity due to transit use.     

The influence of panel effects and inertia on travel cost elasticities for car use and public transport

Transportation - Studies on the impact of changes in travel costs on car and public transport use are typically based on cross-sectional travel survey data or time series analysis and do not...     

Effect of traffic information on commuters' propensity to change route and departure time

Considerable public and private resources are devoted to the collection and dissemination of real-time traffic information in the Chicago area. Such information is intended to help individuals make more informed travel decisions, yet its effect on behavior remains largely unexplored. This study evaluates the effect of traffic information on travelers' route and departure time changes and provides a stronger basis for developing advanced information systems. Downtown Chicago automobile commuters were surveyed during the AM peak period. The results indicate that a majority of the respondents access, use and respond to information. For example, individuals use travel information to reduce their anxiety—even if they do not change travel decisions; this indicates that information may have “intrinsic” value. That is, simply knowing traffic conditions is valued by travelers. More than 60% of the respondents had used traffic information to modify their travel decisions. Multivariate analysis using the ordered probit model showed that individuals were more likely to use traffic reports for their route changes if they perceived traffic reports to be accurate and timely, and frequently listened to traffic reports. Respondents were more likely to change their departure times if they perceived traffic reports to be accurate and relevant, and frequently listened to traffic reports. The implication for Advanced Traveler Information Systems are that they may be designed to support both enroute and pre-trip decisions. ATIS performance, measured in terms of accuracy, relevance and timeliness would be critical in the success of such systems. Further, near-term prediction of traffic conditions on congested and unreliable routes (where conditions change rapidly) and incident durations is desirable.     

Behavioral analysis and transportation planning: Inputs to transit planning

The purpose of this paper is to discuss various types of behavioral data of potential relevance to transit planning. In particular a distinction is drawn between behavorial information regarding feelings, attitudes, opinions, and the like and more sophisticated types of data dealing with individuals' intentions to respond in certain ways given certain configurations of stimuli (transportation variables). The former is shown to be an important input to incremental planning, i.e., where information as to system performance is desired. The latter is shown to be critical to decisions regarding manipulations of transit system parameters, i.e., where knowledge of the outcome of manipulating system parameters is desired.A methodological example as to how the first type of data — informational level data — can be collected and utilized in system planning is presented. Specifically, data collected along the lines of traditional attitude surveys is collected in an attempt to monitor changes in public satisfaction with the Iowa City, Iowa, bus system before and after major system innovations. Implications of the collection and analytical procedures are discussed.This report was produced as part of a program of research and training in urban transportation sponsored by the Urban Mass Transportation Administration of the Department of Transportation.     

康明斯2007年三季度业绩继续保持强劲增长

康明斯公司日前宣布,2007年三季度公司再次取得创纪录的业绩表现,四大事业部中三个部门都刷新了季度销售额历史纪录.     

康明斯2007年业绩再创历史新高

2008年2月14日,康明斯公司公布了2007年度公司财务报告,销售额和利润再创新高,连续四年保持高速增长,美国以外的国际业务占到54%,中国区增长50%.