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41.
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   
42.
This paper considers the issue of women's employment at sea in view of the current and predicted labour shortage in the industry. It reports on an International Labour Organization (ILO) commissioned study which aimed to explore employment policies and practices regarding women seafarers and the experiences of women seafarers themselves. The data suggested that those employers who had experience employing women seafarers were generally very positive about their skills and abilities. Women seafarers themselves were dedicated and committed to a sea-going career. The paper concludes that women seafarers are an under-recognized resource and, if utilized, could fill labour shortages in the industry, both in sea-going positions and in marine positions ashore that require sea-going experience. A series of recommendations are outlined in order to promote the recruitment and retention of women at sea.  相似文献   
43.
44.
This paper attempts to explain the spatial variation of the use of a bicycle for commuting to work at the level of the 589 municipalities in Belgium. Regression techniques were used and special attention was paid to autocorrelation, heterogeneity and multicollinearity. Spatial lag models were used to correct for the presence of spatial dependence and a disaggregated modelling strategy was adopted for the northern and southern parts of the country. The results show that much of the inter-municipality variation in bicycle use is related to environmental aspects such as the relief, traffic volumes and cycling accidents. Town size, distance travelled and demographic aspects also have some effect. In addition, there are regional differences in the effects of the structural covariates on bicycle use: the impact of variables such as traffic volume and cycling accidents differs substantially between the north and the south of the country. This paper also suggests that high rates of bicycle use in one municipality stimulate cycling in neighbouring municipalities, and hence that a mass effect can be initiated, i.e. more cycle commuting encourages even more commuters in the area to cycle. These findings provide some recommendations for decision-makers wishing to promote a shift from car to bicycle use.  相似文献   
45.
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   
46.
Observing the rhythms of daily life: A six-week travel diary   总被引:2,自引:0,他引:2  
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47.
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   
48.
Urban transportation is identified as a functional element in the broader context of urban facilities and services. From this point of view, the relative merits of separate information systems for transportation planning and general urban planning, as contrasted to unified systems for all urban management functions, are discussed. The overriding need to make the most effective use of urban resources argues strongly for the unification of urban information systems to the greatest possible extent consistent with the special data requirements of various functional programs. The need to identify and correlate data items for very small areal units and to keep current records of the constantly shifting patterns of social and economic activities in urban areas present difficult, but not insurmountable technical problems. However, the most serious barrier to the development and implementation of comprehensive urban information systems is concluded to be institutional, rather than technical, in nature.  相似文献   
49.
The absence of formal career-development programmes and the apparent low priority given to the development of human resources in the ports of developing countries has led to a severe shortage of suitably qualified and experienced managers. At the centre of this problem lies the formidable barriers to the establishment of a local training capability to meet the diverse and often specialized needs of this industry. This paper examines the nature and scale of the management-training requirements of the ports of developing countries. Further, it briefly describes the background to UNCTAD's role in the field of management training and outlines the objectives of its training strategy for the 1980s. An important component of this strategy is the 'Improving port performance project which is designed to prepare structured learning materials using audio-visual techniques and is proposed as one solution to establishing a local training capability in developing countries.  相似文献   
50.
This article examines the relationship between refinery margins traded on paper using petroleum futures (the paper refinery) and the physical trade of crude oil into the US. Computations of a 3:2:1 crack spread were constructed using daily observations of second- and third-nearby unleaded gasoline and heating oil futures contracts traded on the New York Mercantile Exchange (NY MEX) and spot Brent crude oil prices. The crack spread represents the margin between the cost of crude oil feed stock today and the value of the products produced by a refinery in the future. Unit root tests on each of the time series found crack spreads to be stationary while crude oil imports were found to be non-stationary. A s the two series were found to be integrated of different order, cointegration analysis of the two series was not deemed appropriate. Instead, linear relationships between crack spreads and imports were examined using causality tests. It was found that the 2-month 3:2:1 crack spread Granger-causes crude oil imports and that this causality is unidirectional. The significance of these findings lies in the fact that other industries like tanker shipping derive their demand from the demand for, and trade in, petroleum. Crack spreads, therefore, can provide a leading indicator for short term developments in tanker demand. For a chartering manager who has ships on the spot market, crack spreads can help him/her anticipate demand developments and influence vessel deployment and chartering decisions.  相似文献   
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