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681.
J. E. Davis 《Maritime Policy and Management》1994,21(1):77-87
This paper traces the evolution of Canadian liner shipping policy from its beginnings, at the time of the initial formation of shipping conferences, in the late nineteenth century, to its current form, as provided by the 1987 Shipping Conference Exemption Act. It is shown that evolution has been associated with a shift in policy orientation from an initial British-based position to a contemporary form that is distincly American in nature. The reasons for this shift are analysed and the similarities and differences between curent Canadian and U.S.A. legislation are identified. The paper shows that the adoption by Canada of an American-style policy became inevitable once the container revolution had physically integrated the transport systems of both nations. 相似文献
682.
Bruce E. Marti 《Maritime Policy and Management》1990,17(3):157-164
The cruise ship industry is currently undergoing a period of rapid expansion. New cruise capacity threatens to produce overtonnaging, with future berths exceeding demand. Despite this development, cruise operators are confident that a growing North American market will be able to satisfy the equilibrium condition sought by vessel operators. This research explores where the new tonnage might be deployed and its eventual impact on the cruise industry. Geographic concepts are utilized to test and support the premise that geography contributes positively to the cruise port selection process. Itineraries, influenced by 'site' and 'situation,' are presently still the most important factor affecting cruise port selection. 相似文献
683.
Steven E. Shladover Deputy Director 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(6):551-595
This paper provides a broad review of the developments that have taken place within the past thirty years in the field now known as Advanced Vehicle Control Systems (AVCS). This long time horizon was chosen to ensure that significant findings from earlier generations of work are not overlooked today. Following a history of the international development of AVCS, several methods of classifying AVCS are introduced. The main body of the paper reviews the relevant literature in lateral, longitudinal and integrated control of road vehicles and summarizes the most significant findings from this work. 相似文献
684.
Effects of Model Complexity on the Performance of Automated Vehicle Steering Controllers: Model Development, Validation and Comparison 总被引:2,自引:0,他引:2
Dirk E. Smith John M. Starkey 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(2):163-181
Recent research on autonomous highway vehicles has begun to focus on lateral control strategies. The initial work has focused on vehicle control during low-g maneuvers at constant vehicle speed, typical of lane merging and normal highway driving. In this paper, and its companion paper, to follow, the lateral control of vehicles during high-g emergency maneuvers is addressed. Models of the vehicle dynamics are developed, showing the accuracy of the different models under low and high-g conditions. Specifically, body roll, tire and drive-train dynamics, tire force saturation, and tire side force lag are shown to be important effects to include in models for emergency maneuvers. Current controllers, designed for low-g maneuvers only, neglect these effects. The follow on paper demonstrates the performance of lateral controllers during high-g lateral emergency maneuvers using these vehicle models. 相似文献
685.
686.
The purpose of this paper is to present the results of a survival analysis for the duration of particular trip-making activities based on sex. Specifically, this study investigates the duration of those activities related to household and family support shopping, personal business, and free time and how these durations vary between men and women. It was found that there were no significant differences in the survival curves (i.e., durations) of free-time or personal business activities; this suggests that men and women spend approximately similar amounts of time on these activities, although it is not known if the activities themselves are similar (for example, banking versus getting gas). Alternatively, sex was found to be a very significant indicator of the duration of household and family support shopping activities. In the model specification, assuming all variables except sex are the same, it was found that women were 1.32 times more likely than men to spend a longer period of time in a household and family support shopping activity. Additionally, it was found that women are 1.33 times more likely than men to have a longer household and family support activity duration if the activity is nested in the journey to work trip. 相似文献
687.
688.
Application of Elementary Neural Networks and Preview Sensors for Representing Driver Steering Control Behaviour 总被引:1,自引:0,他引:1
Charles C. Macadam Associate Research Scientist Gregory E. Johnson Engineer in Research 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1996,25(1):3-30
This paper demonstrates the use of elementary neural networks for modelling and representing driver steering behaviour in path regulation control tasks. Areas of application include uses by vehicle simulation experts who need to model and represent specific instances of driver steering control behaviour, potential on-board vehicle technologies aimed at representing and tracking driver steering control behaviour over time, and use by human factors specialists interested in representing or classifying specific families of driver steering behaviour. Example applications are shown for data obtained from a driver/vehicle numerical simulation, a basic driving simulator, and an experimental on-road test vehicle equipped with a camera and sensor processing system. 相似文献
689.
This paper provides a framework for assessing the progress that is being made in the computer-assisted dispatching of trains. The state of the art is described in general terms, and future research needs are identified. 相似文献
690.
Although the urban transportation planning process has evolved into the most sophisticated of all urban planning processes, the increasirig difficulty in implementing long-range transportation plans in urban areas today suggests basic questions concerning the process which deserve critical examination.Planning for implementation of urban transportation programs, particularly during periods of rapidly changing human values, requires a continuing re-evaluation of both technical and organizational strategies and their interrelationships.This paper raises some fundamental questions about the traditional activities and relationships that have characterized most urban transportation planning programs in the past. It also suggests a number of strategies, both technical and organizational, that may contribute to the implementation of plans and programs resulting from the transportation planning process.The first portion of this paper discusses the implications of not providing transportation services to match metropolitan growth. The experience of the Washington Metropolitan Area over the past decade is used to illustrate these implications.A discussion of organizational and institutional constraints upon the planning process follows. Then, the implications for the planning process are explored, and the scale of planning is reviewed as well as the need for monitoring the performance and impact of facilities.Next, the paper deals with the need to broaden the range of solutions to transportation problems, including consideration of economic and land development policies to reduce travel demand, as well as the provision of new facilities.Finally, techniques for involving decision-makers in the planning process are discussed. Examples of special project activities in the Washington area are used to illustrate these techniques and their value. 相似文献