信息共享平台模型探讨

介绍采用多数据库和数据仓库技术实现信息共享的方法,并在此基础上提出了新型信息共享平台的模型。通过阐述建设信息共享模型的一般过程,说明了该模型的工作原理。模型建立在分布式数据库系统之上,通过全局管理的元数据,可以实现局部异构数据库的存取;通过元数据和元数据基本例程库,可以实现异构数据库间的复制。借助元数据的定义和扩充,该模型可以具有更大的灵活性和可扩展性,实现不同信息系统间的共享。     

基于多传感器信息融合的列车定位方法研究

针对城市轨道交通中列车定位问题,提出了一种基于联邦卡尔曼滤波器的多传感器信息融合列车定位方法,建立了GPS/IPS/DR信息融合模型,对GPS/IPS/DR组合的信息融合定位进行了MATLAB仿真,结果表明,GPS/IPS/DR融合定位能提高列车的定位精度和可靠度,能很好的抑制传统列车定位中的积累误差.     

Will subsidies drive electric vehicle adoption? Measuring consumer preferences in the U.S. and China

We model consumer preferences for conventional, hybrid electric, plug-in hybrid electric (PHEV), and battery electric (BEV) vehicle technologies in China and the U.S. using data from choice-based conjoint surveys fielded in 2012–2013 in both countries. We find that with the combined bundle of attributes offered by vehicles available today, gasoline vehicles continue in both countries to be most attractive to consumers, and American respondents have significantly lower relative willingness-to-pay for BEV technology than Chinese respondents. While U.S. and Chinese subsidies are similar, favoring vehicles with larger battery packs, differences in consumer preferences lead to different outcomes. Our results suggest that with or without each country’s 2012–2013 subsidies, Chinese consumers are willing to adopt today’s BEVs and mid-range PHEVs at similar rates relative to their respective gasoline counterparts, whereas American consumers prefer low-range PHEVs despite subsidies. This implies potential for earlier BEV adoption in China, given adequate supply. While there are clear national security benefits for adoption of BEVs in China, the local and global social impact is unclear: With higher electricity generation emissions in China, a transition to BEVs may reduce oil consumption at the expense of increased air pollution and/or greenhouse gas emissions. On the other hand, demand from China could increase global incentives for electric vehicle technology development with the potential to reduce emissions in countries where electricity generation is associated with lower emissions.     

On a clear day in Ogunquit,Maine

Abstract

Winning a court case against a federal agency may seem to be the sweetest success for an environmental group, but losing litigation is not total failure. In the case of Ogunquit Village Corporation et al., vs. R. M. Davis the plaintiff lost the legal skirmish against the Soil Conservation Service, but in doing so significantly aided the struggle within the agency to implement more environmentally sensitive planning and engineering procedures. This paper describes the court case in terms of the Soil Conservation Service's procedural and policy responses including the agency's modus operandi and the internal paths/pitfalls involved with the implementation of visual resource management. The author also speculates as to the visual resource understanding of the evidence presented by the plaintiff and a possible but unstated visual basis for the original complaint.     

Public transport policy in Canada and the United States: Developing political commitment from the federal government

The United States federal government has been involved in public transport funding for over 40 years, whereas in Canada the federal government has little history of urban public transport policy. In that context, over the past 10 years, Canada has made significant progress in developing new federal commitments for public transport. Critical as these developments have been, however, they do not represent a true National Transit Strategy, which needs to be permanent, predictable and comprehensive. This claim is supported by economic analysis which suggests that Canadian government investment in transit is significantly below the optimal level.     

Judicial Interpretations of Federal Consistency under the Coastal Zone Management Act

The federal consistency provision of the Coastal Zone Management Act (1972) created a new form of interaction between federal and state governments. The implementation of this provision has significant ramifications for coastal management and intergovernmental cooperation in the United States. Past studies have focused on the provision's implementation patterns among U.S. coastal states and federal-state disputes mediated by the Secretary of Commerce. This supplemental article examines judicial interpretations of the federal consistency provision over the past two decades in relation to major issues deliberated by Congress at the time of enactment. Recent changes in the provision, as well as those unresolved issues likely to resurface in future litigation, are also discussed. Seemingly, coastal land use authority and offshore energy exploration remain the most contentious issues surrounding the federal consistency provision.     

A model to identify airport hubs and their importance to tourism in Brazil

Air transportation in Brazil has been recently liberalized and one of the consequences of this process is the concentration of flights in a few hubs. During the years 2006-2007 two fatal accidents created unprecedented chaos in both land and air sides of the system with harmful consequences to tourism in Brazil. The consequences were more airport congestion and many episodes of flight delays and cancellations that lasted for several months. We argue that, among other factors, this state of blackout was a result of the increase in the degree of concentration in few airports, particularly Congonhas (in São Paulo) and Brasília. Using data obtained from a survey with Brazilian experts, a comparison was made with two existing methods (the one used by the US Federal Aviation Administration and the usual Herfindahl-Hirschman method) in order to calculate the number of hubs in Brazil. Due to the huge discrepancy obtained between data from the survey and the other two methods considered, a new mathematical method based on the Herfindahl-Hirschman Index was proposed to identify the number of hubs in a given network. Drawing from the examples of what happened to tourist destinations during and after the air transport crisis in Brazil, the article concludes discussing the need for a more accurate tool to identify and to monitor the concentration of flights at the Brazilian air transportation network and its importance to tourism.     

美国联邦政府在城市交通发展中的角色

简要回顾了美国联邦政府支持联邦公路项目、公共交通项目及都市交通计划的历史,并介绍了能力建设和机构建设等内容。1964年之前,美国一直认为城市公共交通是私有部门盈利行业,属于地方责任,联邦政府没有对公共交通投入资金。直到1964年《城市公共交通法》的出台,联邦政府开始认识到国家经济社会和环境的健康发展离不开城市公共交通的高效运行。2010年美国联邦陆路交通项目资金共约500亿美元,其中105亿美元用于公共交通。     

改进联合滤波在GPS/DR组合定位中的应用

根据低成本车辆GPS/DR组合定位系统传感器精度低和计算能力弱的特点,提出一种改进联合卡尔曼滤波(FKF)算法,并简化主滤波器信息融合算法,稍微降低融合精度,提高计算效率。试验结果表明,提出的改进联合滤波算法具有融合精度高、容错性好、计算量小、便于工程实现等优点。