排序方式: 共有49条查询结果,搜索用时 15 毫秒
21.
Rokicki Bartlomiej Haddad Eduardo A. Horridge Jonathan M. Stępniak Marcin 《Transportation》2021,48(2):747-772
Transportation - Since its EU accession, Poland has invested strongly in the development of fast road transport network. As a result, the total length of modern, high-speed roads has increased from... 相似文献
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提出基于粒子群(PSO)优化最小二乘支持向量机(LS-SVM)的列车弓网系统建模方法。针对LS-SVM的超参数难以选择的问题,提出采用具有全局搜索性能的PSO优化LS-SVM超参数的方法。在建立弓网子系统模型的基础上,得到了弓网系统的整体动力学方程。最后进行弓网系统的仿真实验,结果表明,所提出的PSO优化LS-SVM模型比LS-SVM模型、子空间模型具有更高的预报精度,所提出的方法用于列车弓网系统的建模是有效的。 相似文献
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The jack-up unit is one of the best drilling platforms in offshore oil fields with water depth shallower than 150 meters.As the most pivotal component of the jack-up unit,the leg system can directly affect the global performance of a jack-up unit.Investigation shows that there are three kinds of leg structure forms in the world now:the reverse K,X,and mixing types.In order to clarify the advantage and defects of each one,as well as their effect on the global performance of the jack-up unit,this paper commenced to study performance targets of a deepwater jack-up unit with different leg systems(X type,reverse K type,and mixing type).In this paper a typical leg scantling dimension and identical external loads were selected,detailed finite element snalysis(FEA) models were built to simulate the jack-up unit’s structural behavior,and the multi-point constraint(MPC) element together with the spring element was used to deal with the boundary condition.Finally,the above problems were solved by comparative analysis of their main performance targets(including ultimate static strength,dynamic response,and weight). 相似文献
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In terms of equal sailing distances, where is the inflexion when ships depart from ports in the Asian Continent to New York via Suez and/or Panama?
The answer is China South Port Group (Hong Kong, Shenzhen and Guangzhou). 相似文献
The answer is China South Port Group (Hong Kong, Shenzhen and Guangzhou). 相似文献
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Itis increasingly apparentthatthe main reasonforthe failure of anti- tumor immune response is theinactivation of TIL (Tumor Infiltrating Lympho-cyte,TIL) .The activation of immunocompetentcells is largely dependent on their local microenvi-ronment.Since the tumor local microenvironmentisthe frontier where host immunocompetent cells in-teract with the tumor cells directly,analyzing thetumor local microenvironment,especially compar-ing it to anti- inflammatory immune microenviron-ment,is very… 相似文献
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Fekih Mariem Bellemans Tom Smoreda Zbigniew Bonnel Patrick Furno Angelo Galland Stéphane 《Transportation》2021,48(4):1671-1702
Transportation - Spatiotemporal data, and more specifically origin–destination matrices, are critical inputs to mobility studies for transportation planning and urban management purposes.... 相似文献
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Stéphanie Vincent Lyk-Jensen 《运输评论》2013,33(5):603-624
Trade patterns and transport markets are changing as a result of the growth and globalization of international trade, and forecasting future freight flow has to rely on trade forecasts. Forecasting freight flows is critical for matching infrastructure supply to demand and for assessing investment. This article models long-term dynamic physical trade flows and estimates a dynamic panel data model for foreign trade for the EU15 and two countries from the EFTA (European Free Trade Association) 1967–2002. The analysis suggests that a dynamic three-way-effects gravity equation is the best-fitted econometric model. The analysis uses a structural relationship to explain the structure of the exchange of the goods—a relationship that can be used in the year of forecast. This article also provides a new methodology for converting monetary aggregates into quantity aggregates. The resulting commodity growth rates constitute a valuable input to freight models for forecasting future capacity problems. 相似文献
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Christopher St.John 《舰船科学技术》2011,33(4)
在工程仿真领域,有一家以提供专业化的仿真解决方案享誉业界的公司引起了记者的注意,这家公司何以能在激烈的全球CAE行业中赢得越来越多的市场?其解决方案的特点是什么?其未来发展和技术研发方向是什么?面对中国技术创新的巨大机遇,以及中国已成为造船大国并向造船强国转型的时机下,该公司如何布局中国的CAE市场?其仿真技术和方案能给中国船舶工业转型过程技术创新带来什么益处?带着这些问题,在一个初冬的早晨,本刊记者对这家的全球运营官ChristopherSt.John博士进行了专访。 相似文献
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In this study sail-assisted motor vessels weather routing is investigated to establish the most economical route by applying available information of the ship's behavior regarding the encountered sea-conditions. To derive the vessel’s fuel use on a route, a fuzzy logic model is constructed through an automated identification process. Only data collected from actual integrated bridge measurements systems is used. Fuzzy modeling is a framework providing a flexible and transparent mathematical structure to describe the physical relationships in a vessel's behavior. This consumption model is integrated into a determinist weather-routing optimization workflow based on a systematic meshing scheme of the sailing area. Pareto-optimization with a multi-objective genetic algorithm is used to maximize fuel economy in a limited or optimum time. The benefits of the developed decision helping tool in sail-assisted motor vessel routing are highlighted on a westbound north Transatlantic journey. 相似文献