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881.
J. Hwang D. Lee K. Huh H. Na H. Kang 《International Journal of Automotive Technology》2011,12(1):119-124
The longitudinal and lateral vehicle control techniques have been widely used in several active driver assistance systems.
The adaptive cruise control, lane keeping assistant control, vehicle platooning and stop-and-go control are typical examples
of the most important applications. In this study, a novel path planning method is proposed considering the driving environment
such as road shape, ego vehicle and surrounding vehicles’ movement. The relative distance and velocity between the ego vehicle
and surrounding vehicles are identified with respect to the predicted lane shape in front of the ego vehicle. Based on the
identified information, the road shape and surrounding vehicles are mapped into the intensity image and the desired vector
for the ego vehicle’s movement is determined by the maximum intensity density tracing method. The desired vehicle path is
followed by the acceleration/deceleration control and the steering assist control, respectively. In order to evaluate the
performance of the proposed system, simulations are conducted and compared with ACC systems. 相似文献
882.
Changes in Swiss accessibility since 1850 总被引:2,自引:0,他引:2
This paper discusses the changes in Swiss accessibility since 1850 after arguing that such spatially detailed measures are needed, if one wants to understand the impact of transport investment on the economy and land use patterns.The road-based accessibility overtook that offered by the railways around 1930 and has kept a steady relative lead since then. The relative advantage of the large cities has been eroded since 1950 through their population loss and the massive population gain of the metropolitan fringe. In absolute terms, though, they are still locations with the highest accessibilities. 相似文献
883.
While the literature has established macroeconomic determinants of shipping freight (charter) rates, there has been no systematic
investigation of the microeconomic determinants of shipping freight rates. Therefore, the purpose of this paper is to investigate
microeconomic determinants of freight rates in the dry bulk shipping market, using a large sample of individual dry bulk charter
contracts from January 2003 to July 2009. Differences in freight rates across major dry bulk shipping routes, the geographical
distribution of shipping activities around the world, and the duration of the laycan period of shipping contracts are also
investigated. Estimated results suggest that the laycan period and dry bulk freight rates are interrelated and determined
simultaneously. Furthermore, vessel deadweight, age and voyage routes are important determinants of dry bulk shipping freight
rates, while determinants of the laycan period of chartered vessels include vessel age, freight rate level, and freight rate
volatility. 相似文献
884.
Environmental justice (EJ) assessment has traditionally focused on identifying distributive effects to protected populations. Federal and State highway improvement programs have been established to stimulate economic development for these populations. While this issue has long been recognized as part of EJ initiatives, no quantitative comparisons of highway construction impacts on protected populations have been reported in the literature. This paper presents a dynamic modeling approach to investigate impacts to protected and low-Income populations in highway planning using an integrated Geographic Information System (GIS) and Genetic Algorithms (GAs) optimization framework. Using census and county level parcel data, the model integrates various socioeconomic factors into a GIS while generating highway alignments using GAs. Examples using county level census data from North Carolina are demonstrated to test the sensitivity of generated highway alignments with constrained distances from protected populations. The results indicate that it is important to consider local social and economic effects, in addition to regional planning objectives when measuring the effectiveness of feasibility studies associated with highway construction. Within the proposed modeling framework attention is directed on various EJ initiatives, such as environmental health and safety laws in minority and low-income areas. The model would help planners, designers, and policy-makers understand the intricate interrelationships among local communities, while facilitating more scientific and economically equitable planning for highway construction projects. 相似文献
885.
Conventional design methods require the lane marking patterns, which are painted on ground showing road users the permissible turning directions on different approach lanes, as exogenous inputs to define the traffic stream grouping for analysis. This predefined grouping of traffic movements may restrict the design of signal timings in the optimisation procedures. More recently, a lane-based design method has been developed to relax the lane markings as binary-type control variables in a mathematical programming approach. The lane marking patterns and the signal timings can then be optimised simultaneously in a unified framework. This paper presents an extension work to further relax the numbers of approach lane in traffic arms as new integer variables which can then be optimised to give optimal lane arrangement in various arms of a junction to manage the given traffic demands more efficiently. All well-defined signal timings variables in the phase-based approach as well as the lane marking and lane flow variables in the lane-based approach together with their governing constraints are all preserved in the new formulation for the reserve capacity optimisation of isolated signal-controlled junctions. 相似文献