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431.
This paper describes tailpipe emission results generated by the Vehicle Performance and Emissions Monitoring system (VPEMS). VPEMS integrates on‐board emissions and vehicle/driver performance measurements with positioning and communications technologies, to transmit a coherent spatio‐temporally referenced dataset to a central base station in near real time. These results focus on relationships between tailpipe emissions of CO, CO2, NOx and speed and acceleration. Emissions produced by different driving modes are also presented. Results are generally as one would expect, showing variation between vehicle speed, vehicle acceleration and emissions. Data is based upon a test run in central London on urban streets with speeds not exceeding about 65 km/h. The results presented demonstrate the capabilities of the system. Various issues remain with regard to validation of the data and expansion of the system capability to obtain additional vehicle performance data. 相似文献
432.
The concept of accessibility has been variously interpreted as being the “nearness to places,” the “nearness to activities” and more recently the “ease of participating in activities.” With each of these qualitative interpretations, there has also been a variety of quantitative definitions of accessibility. This paper shows that many of the proposed definitions of accessibility can in fact be gathered together to form a spectrum of accessibility measures. These measures differ with respect to the factors included in their formulation and their degree of behavioural interpretation. Existing measures of accessibility are shown to be deficient in one major aspect. That is, they assume that for any one measure of accessibility there is but one origin of trips. Thus, in estimating the accessibility of a point within a region it is assumed that all potential trips, which contribute to the accessibility of that point, start from that single point. In view of the considerable amount of evidence demonstrating the widespread, and increasing, occurrence of trip‐linking such a proposition must be viewed as being rather doubtful. In the light of this, the paper proceeds to develop a measure of accessibility which explicitly accounts for the linking of trips. The implications of this measure, compared to a conventional unlinked‐trip accessibility measure, are discussed as are some problems which are foreseen in the practical implementation of such a measure. 相似文献
433.
介绍了在独立旋转车轮走行装置方面的研究成果,并探讨了一种复原装置,该复原装置既能保证车辆限界方面的要求,又能保证走行装置的抗脱轨安全性。 相似文献
434.
T.P. Hutchinson R.W.G. Anderson 《Transportation Research Part D: Transport and Environment》2010,15(2):123-125
Attention is called to evidence that in collisions between vehicles of equal mass, and in single-vehicle collisions, there is unlikely to be a very strong effect of car size on injury severity, and that variation in crashworthiness within the set of car models of a given size has a much larger effect. Consequently, the secondary safety of a national fleet of small cars in the future could be as high as that of a national fleet of large cars today. 相似文献
435.
Peter W. de Langen 《WMU Journal of Maritime Affairs》2008,7(1):5-16
The quality and availability of labour is important for the performance of ports. Insights from cluster theories are relevant for analysing training and education in ports, as ports can be regarded as clusters. In general, labour in clusters is relatively mobile, education services in clusters are relatively good and employees have a high willingness to invest in specific skills. However, skilled and talented labour still may be scarce, especially in regions with tight labour markets. Thus, in many clusters, including port clusters, firms and governments actively aim to improve the quality of labour. This paper presents an analysis of these efforts of firms and governments to improve the quality of the labour force in three seaport clusters. In this paper the concept of a ‘training and education regime’ is presented as an approach to analyse efforts of firms and governments to improve the quality and availability of labour. Important results of three case studies include first, the observation that the quality of training and education regime differs substantially between clusters. Second, the presence of aregime manager in Rotterdam adds to the quality of Rotterdam’s training and education regime. Such an organisation may be effective across countries and clusters. Finally, the presence ofleader firms, willing to invest in training and education also improves an education regime. 相似文献
436.
The different types of entry barrier in seaports are analysed and the policies and practices to reduce them are discussed in this paper. In most seaports, economic, regulatory, and geographical entry barriers are substantial and increasing in complexity as ports become embedded in supply chains and multilayered networks with multiple entry-levels. Various entry barriers in seaports are identified through an overview of the relevant literature and their presence is confirmed by empirical data describing them. The case is then made for lowering these barriers. This would be desirable from an economic point of view, since lower barriers strengthen the contestability of markets and increase the level of intra-port competition. The latter might yield substantial benefits, such as fostering specialization and preventing the abuse of market power. Finally, low entry barriers would facilitate the faster implementation of new technologies and business models. In the third part of the analysis, policies and practices designed to reduce entry barriers are examined. The implications are discussed of current national and supranational (EU) policy initiatives aimed to liberalize service provision in seaports. Other (de)regulatory policies that could contribute to the reduction of entry barriers are analysed. 相似文献
437.
This article addresses federal, state, and local regulatory regimes for controlling commercial advertising in coastal waters. It focuses on a new method of outdoor advertising that utilizes a billboard towed by a tug in coastal waters. Specifically, it explores the extent to which legal action to regulate advertising from floating billboards in U.S. waters could withstand constitutional scrutiny. The issue is examined within the contexts of commercial speech and navigational servitude. Additionally, the article discusses the preservation of viewscapes along the coast and the applicability of the public trust doctrine. Jurisdictional issues are examined along with the role of states' harbor management plans and local ordinances in regulating commerce and providing anchorage limitations. The article argues that regulation of floating billboards must not necessarily be based on aesthetics, but the public trust doctrine. The article concludes that the language of the Coastal Zone Management Act (CZMA) and interpretations of its scope, as well as Supreme Court decisions in favor of aesthetic zoning, support the inclusion of such regulations in states' coastal zone management plans. 相似文献
438.
Major accidental oil spills still affect ecologically and economically sensitive marine areas and shorelines, even though environmental programs and policies have led to an increase of ship safety measures. The aim of decision making during oil spill response management is to minimize pollution effects on coastal areas, once spills occur. However, limited equipments or options prevent such a globally satisfying combat strategy. Thus, often preferences between different coastal areas or uses, respectively, have to be made in an operational way. Such a management issue is here taken as a multigroup multicriteria decision-making problem involving a variety of stakeholders and natural dynamic environments. For solving such a complex problem, this article proposes a second order fuzzy comprehensive evaluation (FCE) model, which takes the influence of multiple criteria and the knowledge of different interested groups into account and further provides a basis for simulating a voting-based decision process. With the combination of oil fate simulations and FCE technique, managers are able to realize an integrated management for oil spill. Through a case study of the Prestige accident off the Spanish coast in 2002, it is demonstrated that the model provides a simple, effective and adaptable method to solve operational management problems related to complex human nature interactions as realized during oil spill management. Moreover, a series of analyses and comparisons are focused on to explore potentials and limitations of the FCE for further applications in the field of multigroup multicriteria decision making. 相似文献
439.
James H. Stone Leonard M. Bahr Jr. John W. Day Jr. R. Eugene Turner Paul H. Templet 《Coastal management》2013,41(1):9-35
Abstract Preliminary management guidelines have been derived for oil and gas activities in coastal Louisiana. Derivation of these guidelines was done in terms of the natural function of the coastal ecosystem; this means that all economic activities should be designed to complement natural function as much as possible. The guidelines range in scope from very specific, almost performance standards, to very general admonitions. For example, we have suggested that spoil banks, produced as a result of dredging, should not be higher than the height of the daily tide or roughly 15 cm in coastal Louisiana, and at the other extreme, we have suggested that all dredging should be done with great care during wildlife migrations, spawning, and nesting times. 相似文献
440.
Y. H. Venus Lun Kee-hung Lai Christina W. Y. Wong T. C. E. Cheng 《Maritime Policy and Management》2014,41(2):134-148
Global economic development is facilitated by the commercial shipping industry. Shipping operations contribute to the growth of international trade activities, which heavily count on ships to carry cargoes from places of production to places of consumption. Despite its importance, there have been growing concerns about the environmental impacts caused by shipping activities in international trade. To balance environmental protection and productivity, many shipping firms have begun to adopt green shipping practices (GSPs) to improve their operations in a more environmentally friendly manner. GSP consists of six dimensions, namely, company policy and procedure (CPP), shipping documentation (SD), shipping equipment (SE), shipper cooperation (SC), shipping materials (SM), and shipping design and compliance (SDC). GSP is becoming an important aspect of shipping operations. It is timely for the shipping industry to evaluate firm capability in carrying out greening operations, that is, firms’ “greening” capability. Firm capability comprises two key elements: one is embedded in firms’ business routines or activities, and the other concerns firms’ ability in transforming inputs into outputs. GSPs can be considered as inputs while firm performance measures as outputs. This study uses an input/output approach to examine the greening capability (GC) of shipping firms. The results indicate that shipping firms are relatively weak in the practices of SC and SE, while the capability scores of SM, CPP, SDC, and SD are all close to 1, with an average score of 0.927, 0.920, 0.924, and 0.978, respectively. Academic and managerial significance of the findings are highlighted. 相似文献