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41.
This paper investigates the market potential and environmental benefits of replacing internal combustion engine (ICE) vehicles with battery electric vehicles (BEVs) in the taxi fleet in Nanjing, China. Vehicle trajectory data collected by onboard global positioning system (GPS) units are used to study the travel patterns of taxis. The impacts of charger power, charging infrastructure coverage, and taxi apps on the feasibility of electric taxis are quantified, considering taxi drivers’ recharging behavior and operating activities. It is found that (1) depending on the charger power and coverage, 19% (with AC Level 2 chargers and 20% charger network coverage) to 56% (with DC chargers and 100% charger network coverage) of the ICE vehicles can be replaced by electric taxis without driving pattern changes; (2) by using taxi apps to find nearby passengers and charging stations, drivers could utilize the empty cruising time to charge the battery, which may increase the acceptance of BEVs by up to 82.6% compared to the scenario without taxi apps; and (3) tailpipe emissions in urban areas could be significantly reduced with taxi electrification: a mixed taxi fleet with 46% compressed-natural-gas-powered (CNG) and 54% electricity-powered vehicles can reduce the tailpipe emissions by 48% in comparison with the fleet of 100% CNG taxis. 相似文献
42.
Biodiesel use in local public transport could be especially significant in improving air quality in cities. The purpose of the experiments described in this paper was to evaluate the various (10, 20 and 50%) blends of biodiesel with diesel in the context of the engine and pollution aspects. As regards the experimental use of these findings on municipal buses, these experiments were the first reference in Hungary. The ages (15–20 years) and types of buses (Ikarus-280, Ikarus-260) used in the experiments are still common vehicles in Hungarian public transport. During our measurements, there was a significant difference between the change in fuel consumption of articulated and solo buses in traffic when compared to test bench measurements. The proportion of the engine performance reduction is nearly the same as that for biodiesel share in the blends. Most pollutants were decreasing (both at idle and full rpm), but this reduction is not directly proportional to the increase of the blending percentage. However, as for CO2, emission increase was observed in the case of idle rpm in comparison to normal diesel operation, even though this phenomenon was not due to biodiesel use, but the catalytic converter and the fact that biodiesel was used for the first time in the engine concerned. 相似文献
43.
Managers of public transport systems have been facing for years the strategic challenge of maintaining high quality of transport services to improve the mobility of citizens, while reducing costs and ensuring safety and low environmental impact. A well-established way to evaluate the performance achieved by the system or by specific activities is to monitor Key Performance Indicators (KPI). However, existing management systems, which refer to flexible yet large and complex data models, provide a limited support to define and select relevant KPIs for the objectives at hand, and even the identification of whether and how the data model is capable to achieve a certain informative need is a critical and time-consuming task. This work is aimed to propose a framework to ease the development of a monitoring system in the public transport domain. The approach is based on the ontological representation of all the knowledge regarding indicators and their formulas, business objectives, dimension analysis and their relation with the Transmodel, the European reference data model for public transport information systems. On its top, a reasoning framework provides logic functionalities to interactively support designers in a set of common design tasks: the choice of the most suitable indicators for the performance monitoring needs at hand, the definition of new indicators and the identification of the minimal set of Transmodel modules needed to calculate them. A case study is included to discuss these applications, while an evaluation shows the feasibility of the approach. 相似文献
44.
城市轨道交通客运服务标准编制研究 总被引:5,自引:0,他引:5
城市轨道交通客运服务标准应主要针对乘客的需求而制定,是当前需要优先制定的服务业标准之一。通过对城市轨道交通客运服务及特性进行分析,结合国际相关服务标准以及我国现行的服务标准及标准化模式,提出了“以人为本”、系统性和与国际接轨的标准编制原则。乘客乘车是一个按时间顺序的活动过程,沿乘客乘车时间次序展开服务次序,是标准编制的重要技术方法。确定城市轨道交通客运服务内容是城市轨道交通客运服务标准编制的一项主要任务。在借鉴国外先进服务标准理念的基础上,通过轨道交通客运服务质量和从乘客实际需求出发来规范服务内容。最后,对乘客相应权益的规定做了说明。 相似文献
45.
文章介绍了我国公路工程招标的主要形式,就公路工程招标工作中存在的一些问题,提出了解决建议和应对技巧,为提高与改进公路项目招标工作提供参考. 相似文献
46.
47.
港澳是广东经济发展最重要的外部推动力,是"经济转型"举足轻重的合作伙伴,进一步深化粤港澳各领域合作,是全面深化推进改革的重要举措.基于粤港澳区域经济一体化发展为背景,以航运服务合作为出发点,对国内外关于粤港澳航运服务理论研究的相关文献进行了梳理,归纳粤港澳现代航运服务的发展特点、发展规律、发展现状,总结了粤港澳航运服务存在的问题,针对我国目前在粤港澳航运服务合作机制方面研究空白,提出了今后的研究方向和重点:合作方法和模式研究、合作政策衔接研究、合作策略和措施研究. 相似文献
48.
我国铁路经过6次大提速后,硬件设施水平得到了大幅提升,但与之配套的旅客信息服务体系却相对滞后。目前绝大多数铁路列车上的媒体终端是单向播发系统,研发适合铁路列车的车载移动信息服务平台已迫在眉睫。本文针对铁路旅客信息服务需求,运用系统分析法和功能分析法研发设计了集管理、服务、监控、娱乐四大功能于一体的列车车载移动信息服务平台,该平台的应用功能主要包括列车点餐、视频点播、音乐点播、电子书、新闻发布、广告发布、列车时刻表、整晚点信息发布、游戏、监控等。在车载信息服务平台的基础上,选择平台应用案例中点餐功能进行研究和开发,运用个案研究法实现了基于Android的列车订餐系统。 相似文献
49.
50.
Web 服务的安全作为近年来一个重要研究领域得到了越来越多的重视。论文分析了 SOA 平台下 Web 服务的安全性问题,并对解决这些安全问题的 Web 服务安全规范做了系统的总结。着重描述 WS‐Security 规范以及衍生的其他规范,并对实现跨域单点登陆的 SAML 规范以及描述安全策略的 XACML 进行一定的分析和比较。 相似文献