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51.
D. E. Pitfield 《运输规划与技术》2013,36(1):41-54
A modification to the transportation problem is outlined that aims to improve the quality of predictions of trip matrices, and at the same time, allow some behavioural and economic insights. A framework is suggested within which this modification may be made and a suitable statistic and iterative process are described. A simple example demonstrates the validity of the modification and suggests some areas of difficulty with the approach. 相似文献
52.
John R. E. Russell 《运输评论》2013,33(1):39-58
This paper assesses Danish experience in attempting to integrate traffic with its surroundings in existing areas. Rest and play areas, quiet roads with a 30 km/h speed limit, and major road schemes on urban shopping streets and through villages are all discussed; so too are policies seeking to create safe routes to school, the problems arising from the introduction of speed reduction measures on bus routes, and the merits of area‐wide as opposed to incremental approaches. Evaluations indicate that speed reductions to a maximum of 30 km/h are achievable on local roads, and that the quiet street approach represents a cost‐effective and popular means of achieving environmental improvements and safer, more liveable streets for residents. It is recommended as an appropriate model for Britain to follow. Incremental implementation risks being sub‐optimal in design terms but has distinct advantages in minimizing conflicts and enabling rapid implementation. Evaluations of shopping street and village schemes are incomplete but speed reductions and environmental gains have undoubtedly been achieved. 相似文献
53.
David W. Laist Thomas E. Bigford George W. Robertson Doria R. Gordon 《Coastal management》2013,41(3-4):203-239
Abstract Corals and coral communities provide substantial societal benefits by virtue of their recreational and esthetic appeal, the habitat provided for commercially harvested fish and shellfish, the structural foundation provided for productive coastal ecosystems, and the market value of harvested coral specimens. Coral resources are subject to adverse effects from pollution, dredging, specimen collecting, anchor damage, commercial fishing, overharvesting, and activities related to offshore petroleum development. Management programs which protect coral resources in the United States comprise a patchwork of separate federal and state programs. They attempt to adapt broad regulatory authorities for parks, fisheries, offshore mineral resources, and other subjects for the purpose of coral conservation. These programs embody species‐specific, area‐specific, and generic approaches to coral management. This paper traces the evolution of U.S. coral management programs and comments on their respective strengths and weaknesses. Alternative approaches for strengthening management systems could include new coordinating committees, legislation, memoranda of agreement between involved agencies, and others. 相似文献
54.
Carlos Jerome Lawrence A. Howard Ezgi Uzel Jameela R. Androulidakis 《WMU Journal of Maritime Affairs》2017,16(1):89-98
Protection against on-ship infectious disease—whether due to mishap or to harmful purpose—faces special situational problems. Sometimes, when infection levels on board have reached threshold levels, emergency actions are required. Often, the most thorough strategies for responding to threat are not feasible. A rapid first-stage test (RFT) is a fast, minimally invasive procedure used to rule out from possible infection a large percentage of an infection-threatened group. Prevention and control of on-ship infection need to combine various interconnected tactics. When timely criterion tests are not possible, the medical team must adopt fast alternative measures. The methods used to summarize protection against on-ship infectious agents included a scientific literature review and a web search. The fields of the review were maritime, health, and technology sources. Special attention was paid to material dealing with risks and threats of on-ship penetration by infectious agents, on-ship infection prevalence thresholds, and rapid diagnostic screens. The Bayes rule and the law of large numbers were applied to the analysis, for large on-ship populations, of RFT indications of crossing of an infection prevalence threshold. The increasing risk of serious on-ship infection—either accidental or purposeful—calls for a multi-layered protection approach. RFTs are a key part of the outer layer of such a defense. Well-designed and well-administered RFTs provide several advantages for defense against on-ship infection: low-cost, non-invasive, fast, and focuses on a drastically smaller number of infection possibilities. 相似文献
55.
D. I. Katzourakis E. Velenis E. Holweg R. Happee 《International Journal of Automotive Technology》2014,15(1):151-163
Current vehicle dynamic control systems from simple yaw control to high-end active steering support systems are designed to primarily actuate on the vehicle itself, rather than stimulate the driver to adapt his/her inputs for better vehicle control. The driver though dictates the vehicle’s motion, and centralizing him/her in the control loop is hypothesized to promote safety and driving pleasure. Exploring the above statement, the goal of this study is to develop and evaluate a haptic steering support when driving near the vehicle’s handling limits (Haptic Support Near the Limits; HSNL). The support aims to promote the driver’s perception of the vehicle’s behaviour and handling capacity (the vehicle’s internal model) by providing haptic (torque) cues on the steering wheel. The HSNL has been evaluated in (a) driving simulator tests and (b) tests with a vehicle (Opel Astra G/B) equipped with a variable steering feedback torque system. Drivers attempted to achieve maximum velocity while trying to retain control in a circular skid-pad. In the simulator (a) 25 subjects drove a vehicle model parameterised as the Astra on a dry skid-pad while in (b) 17 subjects drove the real Astra on a wet skid-pad. Both the driving simulator and the real vehicle tests led to the conclusion that the HSNL assisted subjects to drive closer to the designated path while achieving effectively the same speed. With the HSNL the drivers operated the tires in smaller slip angles and hence avoided saturation of the front wheels’ lateral forces and excessive understeer. Finally, the HSNL reduced their mental and physical demand. 相似文献
56.
Maren L. Outwater Greg Spitz John Lobb Margaret Campbell Bhargava Sana Ram Pendyala William Woodford 《Transportation》2011,38(4):605-623
This research seeks to improve the understanding of the full range of determinants for mode choice behavior and to offer practical
solutions to practitioners on representing and distinguishing these characteristics in travel demand forecasting models. The
principal findings were that the representation of awareness of transit services is significantly different than the underlying
assumption of mode choice and forecasting models that there is perfect awareness and consideration of all modes. Furthermore,
inclusion of non-traditional transit attributes and attitudes can improve mode choice models and reduce bias constants. Additional
methods and analyses are necessary to bring these results into practice. The work is being conducted in two phases. This paper
documents the results of Phase I, which included data collection for one case study city (Salt Lake City), research and analysis
of non-traditional transit attributes in mode choice models, awareness of transit services, and recommendations for bringing
these analyses into practice. Phase II will include data collection for two additional case study cities (Chicago and Charlotte)
with minor modifications based on limitations identified in Phase I, additional analyses where Phase I results indicated a
need, and a demonstration of the research in practice for at least one case study city. 相似文献
57.
Y.H. Venus Lun Michael BrowneKee-hung Lai Christina W.Y. WongT.C.E. Cheng 《Research in Transportation Economics》2011,32(1):64-70
Container shipping and its related service sectors help accelerate globalization of the world economy. This industry has been experiencing rapid growth, prompting container terminal operators to increase their handling capacity in response. Providing container terminal services requires substantial capital investment in physical assets such as cargo handling facilities and information systems. On the other hand, operating container terminals is a long-term investment that typically spans several business cycles. Hence prudent asset management using appropriate tools is critical for container terminal operators to sustain their businesses. Generally, due to risk-adverseness, investors are unwilling to take more risk in their investment unless they can reap a higher return. Contrary to this argument, this study finds no direct influence of better firm performance as a proxy of higher return on business risk-taking by container terminal operators. Instead, scale of operations is positively associated with business risk-taking, suggesting that container terminal operators with a larger scale of operations are willing to take more business risk. 相似文献
58.
Nicole A. Costa Jeanette J. Jakobsen Reto Weber Monica Lundh Scott N. MacKinnon 《WMU Journal of Maritime Affairs》2018,17(4):521-542
The aim of this study was to assess proof of concept and usability of a maritime service website prototype in a full-mission ship bridge simulator through Swedish mariners’ experiences and perceptions. This test was part of the European Commission’s EfficienSea2 project for e-navigation. The prototype was intended as an aid to existing standard systems and methodologies for planning, executing and monitoring voyages. The study began with 5 days of simulator trials focused on today’s standard practices. This served as a baseline to compare to subsequent 4 days of simulator trials testing the prototype. For data collection, observations, video footage, interviews, and eye tracking were used. Data analysis included breaking apart the qualitative data to capture the perceptions of the participants, and a preliminary analysis of eye-tracking data as a complement. The results suggested that the prototype could be more suitable for a route planning stage, that the participants were familiar with similar existing solutions from other manufacturers, and that the contents of the tool would be most beneficial if integrated within the Electronic Chart Display and Information Systems (ECDIS). There is a pressing need for the novel solutions to be user needs-driven, integrated with the existing technologies, and standardized across the domain, and these processes must go hand-in-hand with accounting for all involved stakeholders, procedures, regulations, and training, as this will alter the course of shipping. 相似文献
59.
An analysis of the determinants of children’s weekend physical activity participation 总被引:1,自引:0,他引:1
This paper examines the out-of-home, weekend, time-use patterns of children aged 5–17 years, with a specific emphasis on their
physical activity participation. The impact of several types of factors, including individual and household demographics,
neighborhood demographics, built environment characteristics, and activity day variables, on physical activity participation
is analyzed using a joint nested multiple discrete–continuous extreme value-binary choice model. The sample for analysis is
drawn from the 2000 San Francisco Bay Area Travel Survey. The model developed in the paper can be used to assess the impacts
of changing demographics and built environment characteristics on children’s physical activity levels. 相似文献
60.
H. E. Tseng 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2001,36(4):307-328
Road bank angles have a direct influence on vehicle dynamics and lateral acceleration measurement. A vehicle stability control system that knows road bank angle has an advantageous capability in achieving desired control sensitivities for maneuvers on ice and snow, among all surfaces, while avoiding false/nuisance activation on a banked road. Since neither lateral velocity nor road bank angle are directly measurable in current vehicle systems due to economical reasons, the major challenge is to differentiate the bias induced by road bank disturbances from actual effect of vehicle lateral dynamics in current measurements. This paper proposes a method of road bank estimation and provides theoretical background for the decoupling effort of lateral dynamics and road disturbances involved in bank estimation. 相似文献