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Chang Doo Jang Jong Jin Jung Alexander A. Korobkin 《Journal of Marine Science and Technology》2007,12(2):95-101
This article describes an estimation method for the hull girder response of a ship due to springing. The linear and nonlinear
springing effects on the hull girder are evaluated. Previous studies on the springing response focused mainly on the symmetric
response, or vertical response. In this article, however, the springing analysis is extended to asymmetric responses, or horizontal
and torsional responses. The Timoshenko beam model was used to calculate the hull girder response and the quadratic strip
method was employed to calculate hydrodynamic forces and moments on the hull. To remove irregular frequencies, a rigid lid
was adopted on the hull free surface level and hydrodynamic coefficients were interpolated for asymptotic values. Applications
to two ships for the symmetric and asymmetric responses were carried out and the effect of springing responses is also discussed. 相似文献
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Modeling traffic operation at signalized intersections without explicit left‐turn yielding rules with an enhanced cell transmission model 下载免费PDF全文
This paper presents an enhanced cell transmission model (CTM) to capture traffic operation at signalized intersections without explicit permissive left‐turn yielding rules (i.e. aggressive permissive left‐turn maneuvers may not necessarily yield to opposing through traffic), which can be widely observed in many developing countries. Different from previous studies that focus on traffic dynamics on approaching links, this study contributes to modeling traffic operations within the intersection. A novel cell transmission framework with various types of virtual cells is proposed to model the dynamics of traffic movements from approach to exit. The unique phenomenon of competitive occupying of the conflict point between the left turn and opposing through movements is modeled. The cell state indicating its blockage is proposed to capture the dynamic queue formulation and dissipation and to evaluate the operational traffic performance at the intersection. Field validation results show that the proposed model can capture the operation of traffic at signalized intersections without explicit permissive left‐turn yielding rules with significantly higher level of accuracy than traditional traffic flow models. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Effective prediction of bus arrival times is important to advanced traveler information systems (ATIS). Here a hybrid model, based on support vector machine (SVM) and Kalman filtering technique, is presented to predict bus arrival times. In the model, the SVM model predicts the baseline travel times on the basic of historical trips occurring data at given time‐of‐day, weather conditions, route segment, the travel times on the current segment, and the latest travel times on the predicted segment; the Kalman filtering‐based dynamic algorithm uses the latest bus arrival information, together with estimated baseline travel times, to predict arrival times at the next point. The predicted bus arrival times are examined by data of bus no. 7 in a satellite town of Dalian in China. Results show that the hybrid model proposed in this paper is feasible and applicable in bus arrival time forecasting area, and generally provides better performance than artificial neural network (ANN)–based methods. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Nadia Magnenat‐Thalmann 《运输规划与技术》2013,36(4):275-279
The system described in this paper allows the user to visualize the Montreal transportation system. The user is provided with several different maps. The complete subway network and all regular bus lines have been included. The subway network and the bus lines can be selectively displayed. The most attractive feature of this system is the possibility of obtaining all possible routes between two different places. The input is based on the menu technique. The system can be easily adapted to other large urban transportation systems. 相似文献
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Valuation of externalities is a condition for correct investment and pricing decisions in transport. This paper provides a brief survey of the main studies achieved in OECD countries in order to get these valuations. Numerical values for the average social cost of transport are presented. The procedures according to which environment is taken into account in France and Italy are analyzed, and the importance of valuation in these procedures is assessed. Finally, prospects for further research and new developments are expressed. 相似文献
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The purpose of this paper is to implement an efficient method for GIS‐based traffic analysis zone (TAZ) design in order to evaluate and validate such a method. The method was developed by the authors. Moran's I spatial autocorrelation coefficient and sample variance are used for evaluating the generated TAZs using the Champaign‐Urbana, IL region as a case study. Sensitivity analysis is also conducted to explore the fluctuations in TAZ generation outcomes. The evaluation, the validation as well as the TAZ design have been implemented with ARC/INFO GIS software on a UNIX workstation platform. 相似文献
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Due to additional trip production by land use development, the O‐D travel costs between some O‐D pairs may also change intuitively. This leads to positive and negative impacts on network users traveling between different O‐D pairs. Therefore the equity issue about the benefit distribution gained from the land‐use development problem is raised. This paper proposes an Equity based Land‐Use Transportation Problem (ELUTP) which is intended to examine the benefit distribution among the network users and the resulting equity associated with land‐use development problem in terms of the change of equilibrium O‐D travel cost. In the resulting bi‐level programming model, the upper level sub‐problem maximizes traffic production incorporating equity constraints, while the lower level sub‐problem is a combined trip distribution/assignment user equilibrium problem. Genetic algorithm based method is applied to test the models using an example network. 相似文献
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Yeong‐il Kang† 《运输评论》2013,33(4):357-370
The urban bus industry in Korea used to be controlled to provide stable transport services and enable operators to secure proper profits, but there were adverse effects within the industry such as inadequate business management and a downward spiral of low quality services resulting from lower fares. The government began easing restrictions on entry, operation, fares, and some conditions and procedures for licensing in the late 1980s, until in 1993, the government published a package of deregulatory measures that were considerably more drastic than those previously seen, such as freely adjusting the number of vehicles within 10%, easing the restrictions and requirements for operators’ employing staff and drivers, and improving the fare system. However, these measures seem to have been introduced too late and too luke‐warmly to encourage new entrants to the industry. Therefore, to gain the desirable effects of deregulation and to secure the development of the urban bus sector, there needs to be provision of a market atmosphere and greater scope for free competition; a positive attitude among operators for efficient business management and new services; and alert observation and monitoring by passengers. 相似文献