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101.
102.
Demand for commercial air travel has been increasing over the years and recent forecasts indicate similar future trends. New aircraft with enhanced design features are being built and entering the airline service globally. These enhancements aim to ensure continued safety, efficiency, performance and prolonged life serviceability. However, these new enhancements often neglect the impact of the changing anthropometric characteristics of the passenger. Past studies have identified increasing trends in the average weight, height and other anthropometrical and biometrical measures of people at a global scale. However, many are limited to only exploring the ramifications primarily from the perspective of passenger experience. This paper highlights the importance of considering passengers’ anthropometric characteristics from a holistic perspective and identifies gaps for future research. 相似文献
103.
David A. Eerdmans Didier M. van de Velde Hans Westerink 《Research in Transportation Economics》2010,29(1):133-139
This paper presents a number of reasons that are responsible for the disappointment of authorities in their operators’ efforts to develop public transport (PT) to the advantage of their travellers. The lessons drawn in this paper are based upon the competitive tendering experience of the authors and upon the results of meetings organised with parties involved in competitive tendering and aimed at exchanging lessons. There appears to be three main causes: (1) there is freedom for the operator, but the contract is bad; (2) there is freedom for the operator, there is a good contract, but there is no market; and (3) there is freedom for the operator, but the operator is not able to use it. The paper concludes with a few perspectives for improvement. 相似文献
104.
The 2008 credit crunch and the subsequent economic crisis ended a period that lasted over two decades wherein international seaports around the globe experienced double-digit volume increases. This chapter provides an analysis of the structural effects that the crisis has on seaports, focusing mostly on developments in Europe. It does so via an examination of (a) the crisis implication for each of the four major types of transport flows that account for the vast majority of port throughput worldwide; (b) the prospects for future capacity organisation and development, given the realignment of the involvement strategies that the various stakeholders (i.e., governments, port authorities, service providers, users, investors) endorse in reaction to the financial tsunami; and (c) the adjustment opportunities, that the trade downturn unintentionally provides, allowing for correction of existing misallocations in the sector via the deployment of relevant adjustment strategies by the related actors. Recapping the identified structural consequences, the final section concludes on the changing role and responsibilities of port authorities and the ‘new issues’ that will require further investigation in the post-financial tsunami era. 相似文献
105.
Efficient maritime navigation through obstructions at close range is still one of the many problems faced by mariners. The
increasing traffic densities and average cruise speed of ships also impede the collision avoidance process by reducing the
time available for decision making. This study develops a path-planning algorithm that determines an optimal navigation path
for ships in close-range encounters, using known and predicted data about the traffic and environment. An improved ship dynamic
model has also been developed to better approximate the ship movement under external influences, and the algorithm was evaluated
with a set of test cases simulating various traffic scenarios typically encountered at close range. Since the method is based
on evolutionary algorithm, the algorithm behaviours were evaluated statistically, where properties such as consistency and
practicality of the algorithm outputs are discussed. 相似文献
106.
Can agents measure up? A comparative study of an agent-based and on-line optimization approach for a drayage problem with uncertainty 总被引:1,自引:0,他引:1
Tams Mhr Jordan Srour Mathijs de Weerdt Rob Zuidwijk 《Transportation Research Part C: Emerging Technologies》2010,18(1):99-119
Experiments studying the behavior of agent-based methods over varying levels of uncertainty in comparison to traditional optimization methods are generally absent from the literature. In this paper we apply two structurally distinct solution approaches, an on-line optimization and an agent-based approach, to a drayage problem with time windows under two types of uncertainty. Both solution approaches are able to respond to dynamic events. The on-line optimization approach utilizes a mixed integer program to obtain a feasible route at 30-s intervals. The second solution approach deploys agents that engage in auctions to satisfy their own objectives based on the information they perceive and maintain locally. Our results reveal that the agent-based system can outperform the on-line optimization when service time duration is highly uncertain. The on-line optimization approach, on the other hand, performs competitively with the agent-based system under conditions of job-arrival uncertainty. When both moderate service time and job-arrival uncertainties are combined, the agent system outperforms the on-line optimization; however, in the case of extremely high combined uncertainty, the on-line optimization outperforms the agent-based approach. 相似文献
107.
Audrey de Nazelle Brian J Morton Michael Jerrett Douglas Crawford-Brown 《Transportation Research Part D: Transport and Environment》2010,15(8):451-457
This paper examines how conversion of automobile trips of less than 3 miles to other transportation modes reduces emissions. Short trips contribute disproportionately to emissions because of cold starts. An analysis is conducted of short-trip behavior across the US using the 1995 Nationwide Personal Transportation Survey. The data is used to develop likely scenarios of mode conversions for short trips, which are then applied to estimate emission savings using MOBILE6 cold start and running emission factors for volatile organic compounds, nitrogen oxides, carbon monoxide, and carbon dioxide. The results suggest that reducing short auto trips would modestly reduce mobile source air pollution, but emission reductions are high compared to most federally-funded surface transportation interventions aimed at improving air quality. Enhanced the community pedestrian environment to encourage short trip mode conversion also produces co-benefits such as increased physical activity and subsequent reductions in chronic diseases. 相似文献
108.
Richard Morris 《Maritime Policy and Management》1993,20(1):67-75
Australia's merchant fleet underwent a delayed response to the trends responsible for the attrition of the OECD fleets over the past decades. A combination of political factors and the heritage of protectionism led to centrally-directed and government-sponsored programmes of modernization. Essentially, compliance with the federal government's shipping policy was achieved through the linkage of reform to tax incentives and to the management of change by tripartite shipowner, government and trade union committees. This paper explores the basic pattern of the reforms, their costings, assessment and policy alternatives. 相似文献
109.
110.
Anouk de Brauwere Benjamin de Brye Sébastien Blaise Eric Deleersnijder 《Journal of Marine Systems》2011,84(3-4):85-95
Residence times and exposure times are computed for 13 boxes in the Scheldt Estuary, using the high-resolution tracer-transport model SLIM. The concepts are clearly defined and related to how they should be computed. First, the timescale values are compared with results published previously that were obtained with a simple box model, and an unexpected difference is revealed. This may suggest that a high-resolution model is necessary, even for the computation of such integrated quantities as residence or exposure times. Secondly, the newly computed residence times are compared to the exposures times to illustrate their intrinsic differences. From this difference, it is possible to propose a return coefficient, expressing the fraction of the exposure time that is due to “returning water”, i.e. water which has already left the estuary at least once. Finally, the estuarine exposure times are decomposed into the different box exposure times, resulting in a connectivity matrix. This matrix expresses how much time is spent in each of the estuarine subdomains during the water parcels' journey through the estuary. 相似文献