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11.
Work relevant to the state of the art as regards passenger cars towing trailers is referenced and reviewed. Not only included is the very limited amount of work specifically dealing with passenger cars towing trailers, but also reviewed is the much larger body of work having a bearing on car-trailer systems. Topics included are aerodynamic forces, tire forces, the compliance concept, relevant work on vehicles without trailers, vehicles with trailers, and the role of the driver. The types of stability problems exhibited by car-trailer systems are discussed.

The state of the art as regards ability to predict vehicle response to specific steering inputs is shown to be fairly advanced. Recent significant advances include the appearance of experimental data useful for validating theoretical models. However, the state of the art as regards definition of what constitute desirable handling characteristics is still at a primitive stage, largely because of a lack of understanding of the roles played by drivers as part of the vehicle -driver - environment systems.

Throughout the review an effort was made to point out topic areas where it is likely that significant future contributions to the state of the art can be made. These areas are reviewed in the conclusions.  相似文献   
12.
To facilitate the commercialization of wave energy in an array or farm environment, effective control strategies for improving energy extraction efficiency of the system are important. In this paper, we develop and apply model-predictive control(MPC) to a heaving point-absorber array, where the optimization problem is cast into a convex quadratic programming(QP)formulation,which can be efficiently solved by a standard QP solver. We introduced a term for penalizing large slew rates in the cost function to ensure the convexity of this function. Constraints on both range of the states and the input capacity can be accommodated. The convex formulation reduces the computational hurdles imposed on conventional nonlinear MPC. For illustration of the control principles,a point-absorber approximation is adopted to simplify the representation of the hydrodynamic coefficients among the array by exploiting the small devices to wavelength assumption. The energycapturing capabilities of a two-cylinder array in regular and irregular waves are investigated. The performance of the MPC for this two-WEC array is compared to that for a single WEC, and the behavior of the individual devices in head or beam wave configuration is explained. Also shown is the reactive power required by the power takeoff system to achieve the performance.  相似文献   
13.

An integrated method for benthic habitat assessment is described, in which divers maneuver boards equipped with digital video, temperature, and depth recorders while being towed behind a small boat. The tow path is concurrently recorded by a GPS receiver, and a layback model is applied to more accurately map the data. Percent cover of salient benthic categories is quantified by whole-image analysis of still frames sampled at 30-s intervals. The results of 15 towed-diver surveys at Midway Atoll in the Hawaiian Archipelago during a mass coral bleaching event are presented to exemplify the method and are compared to results derived from conventional methods. Towed-diver surveys bridge a gap between large-scale mapping efforts using satellite data and small-scale, roving diver assessments, providing a mesoscale spatial assessment of reef habitats. The spatial coverage of towed-diver surveys provides comprehensive data to managers concerning the extent, intensity, differential taxonomic response, and bathymetric correlates of bleaching.  相似文献   
14.
Abstract

In some cases, the major risk encountered by an industry seeking to site a facility is that of community acceptance. Without community acceptance of a proposed project, construction can be delayed, taxes can be prohibitive, and operations can be prevented through the opposition and influence of local groups. This paper describes the community acceptance risk, the traditional industrial approach to countering local opposition, and a positive approach to achieving community acceptance. This positive approach entails careful site selection; affirmative management of the community acceptance problem, including explicit planning of the community acceptance effort, assignment of staff with specific responsibilities to implement plans, and a budget for mitigating the impacts of the project on the community; acquisition of sufficient land to buffer unavoidable impacts of the project; a carefully formed corporate policy on the public release of information concerning the project; and constructive participation in state and local government policy development.  相似文献   
15.
This paper reviews a number of recent innovations in the regulation and operation of taxicabs in U. S. cities. The paper discusses the growing involvement of various levels of government in public transportation programs which affect the taxicab industry, and identifies the opportunities and problems created for the industry by this increased government activity. Innovations in the types of public transportation services which can be provided by taxicabs are discussed first, followed by a review of the administrative procedures which can be employed to involve taxicab companies in publicly funded programs. Proposals for changes in the regulations governing taxicab services and prices are discussed next, with particular attention to significant regulatory changes which have been implemented in U.S. cities in recent years. Finally, innovations in the technology of taxicab operations are reviewed, including improvements to vehicles, computerized dispatching techniques, and procedures and equipment for computing fares for taxicab services.  相似文献   
16.
Several shared-ride passenger transportation services which could be offered by taxicabs are currently prohibited in U.S. cities by state or local regulations. Although relaxation of these regulations has been advocated on numerous occasions, little regulatory change has occurred to date. Moreover, the taxicab industry has rarely been considered as a potential provider for publicly subsidized transportation services. This paper discusses several promising innovations in taxicab service provisions and subsidy mechanisms which have been implemented or proposed recently in U.S. cities. The paper argues for more well-designed experimentation with such innovations as a means of stimulating greater interest on the part of planners, policy-makers, regulators, and public transportation operators in broadening the role of taxicabs in urban transportation.  相似文献   
17.
1 背景 在1989年以前,汽车行业没有一个专门的氙灯加速老化测试方法的国际标准.1989年,汽车工程学会(SAE)发布了J1960"水冷式氙灯汽车外饰件加速暴露测试"和SAE J1885"水冷式氙灯汽车内饰件加速暴露测试"两项汽车材料耐候性测试标准.当时,SAE J1960和J1885有利于汽车制造商统一测试条件.但是,这些老化测试标准基于特定型号的设备构造,指定了某生产商的两种型号设备.  相似文献   
18.
This paper provides a review of transport model applications that not only provide a central traffic forecast (or forecasts for a few scenarios), but also quantify the uncertainty in the traffic forecasts in the form of a confidence interval or related measures. Both uncertainty that results from using uncertain inputs (e.g. on income) and uncertainty in the model itself are treated. The paper goes on to describe the methods used and the results obtained for a case study in quantifying uncertainty in traffic forecasts in The Netherlands.
Gerard de JongEmail:
  相似文献   
19.
Fishing is one of the most dangerous occupations in the world. Numerous research studies have been carried out to improve fishing safety from many different perspectives. Several of these studies focused on the relationship between environmental factors, climate change effects, and fishing safety. This paper aims to suggest a knowledge mobilization structure that translates findings of this type of research into input of evidence-based decision making and consequently improve and update fishing policies with respect to fishing safety and environmental conditions. Significant safety factors extracted from related literature are stability of vessels, fisheries management, safety equipment, communication, insurance, training, safety information and culture, weather forecasts, fatigue, and search and rescue planning. The paper then reviews policies related to these factors to examine if they address extreme environmental conditions and climate change effects. The paper presents recommendations to improve general fishing safety with respect to short- and long-term environmental considerations.  相似文献   
20.
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