NEW METHOD FOR DERIVING OPTIMAL REDUCT

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Study on Performances of Car-following Models Induced by Motions of a Leading Car

IntroductionReasonably accurate mathematical modeling oftraffic engineering is needed not only for better un-derstanding of the collective behavior of traffic,but also for analyzing flow conditions, designingefficient control strategies, and etc[1]. For the pastfew decades, many researchers made studies of thissubject and a wide range of traffic flow theoriesand models have been developed. According to thelevel-of-detail with which the traffic flow is de-scribed, these traffic models were clas…     

Image series segmentation and improved MC algorithm

A semiautomatic segmentation method based on active contour is proposed for computed tomography （CT） image series. First, to get initial contour, one image slice was segmented exactly by C-V method based on Mumford-Shah model. Next, the computer will segment the nearby slice automatically using the snake model one by one. During segmenting of image slices, former slice boundary, as next slice initial contour, may cross over next slice real boundary and never return to right position. To avoid contour skipping over, the distance variance between two slices is evaluated by an threshold, which decides whether to initiate again. Moreover, a new improved marching cubes （MC） algorithm based on 2D images series segmentation boundary is given for 3D image reconstruction. Compared with the standard method, the proposed algorithm reduces detecting time and needs less storing memory. The effectiveness and capabilities of the algorithm were illustrated by ,experimental results.     

平面交叉路口信号灯自动配时方案的优化算法

章提出了一种平面交叉路口的通用模型及描述各种实际路口的方法，根据路口各车流向的期望车流量实时预测结果，实时给出最优配时方案的算法。最后总结了算法的优点。     

Unsupervised Linear Discriminant Analysis

Introduction As a supervised learning algorithm,linear dis-criminant analysis(LDA)is widely used in manyfields,such as face recognition,numerical recogni-tion and information retrieval.The objective ofLDA is to find a project matrix A that maximizesthe ratio of between-class scatter Sbagainst within-class scatter Sw[1].In contrast,an algorithm forunsupervised linear discriminant analysis(ULDA)is presented in this paper.The project matrix A isobtained through maximizing covariance of all …     

汽车发动机冷却风扇对机舱热管理影响的研究

文章应用CFD软件STAR CCM+及AMEsim研究了汽车发动机冷却风扇对机舱热管理的影响,在建立三维整车热管理系统数值模型的同时,建立了发动机冷却系统一维仿真模型。得到了车辆在不同转速和车速下散热器和冷凝器的进风量,分析了不同车速下,发动机冷却风扇转速与冷却模块进风量之间的关系,以及散热器进风量对发动机冷却液水温的影响。结果表明:随着车速的提高,风扇转速对散热器进气量的影响逐渐降低。当车速小于60km/h时,风扇转速对散热器进气量的增加有明显的作用;结合车辆开发性能要求,通过一维、三维联合仿真确定了该车辆发动机冷却风扇的合理转速,并且验证了所选风扇转速的合理性和可靠性。     

半潜钻井平台辐射问题的高精度算法研究

附加质量和阻尼力是决定半潜式钻井平台运动响应的重要参数,该研究采用直交边界边配置多重节点的新方法去除积分边界的奇异性。研究中同时应用了高阶边界单元方法近似真实的空间三维复杂结构,依据波浪与结构物相互作用的辐射和绕射理论建立边界元积分方程,对ISSC型半潜式平台（Semi-Submersible）的附加质量和阻尼力进行了分析研究。研究表明多重节点与高阶边界元相结合的方法对复杂结构的水动力计算具有很高的精度。     

基于DSRC的ITS电子收费系统研究

电子收费系统（ETC，Electronic Toll System)是智能交通系统（ITS，Intelligent Transportation System)体系结构中一个重要的组成部分，在国外有着广泛的应用，也是ITS体系中发展较为成熟的技术。把联网ETC系统置于ITS体系中加以研究，分析了电子收费系统的结构组成、数据流动模型、资金在银行系统的流动模型和与ITS其它子系统的接口模型。通过ITS数据通信协议（TCIP，Transportation Communication for ITS Protocol)，可以充分利用ETC信息，实现信息与ITS体系中其它子系统共享。同时实现各个ETC系统之间的协同工作，提出以专用短程通信（DSRC，Dedicated Short Range Communication)技术为基础的实现策略。最后对系统实现的关键技术加以说明。     

水下上弧形板结构的水动力特性研究

文章应用边界单元法,依据波浪绕射和辐射理论研究了一种新型的板式防波堤结构—上弧形板结构。研究中通过与另外三种板式防波堤结构(下弧形板结构,单板结构,双层板结构)的对比,验证了这一新型结构具有更好的消波效果。文中重点分析了这种新型结构的散射波浪力、透射系数和反射系数,并且为了进一步揭示这种结构的消波原理,对该结构周围的流场进了分析。研究发现：（1）上弧形板结构在横荡方向上所受波浪力最小。（2）当潜深波高比为0.05时,该结构的消波效果比其他三种结构增强约50%。（3）通过对上弧形板结构的速度流场分析,发现上弧形板结构上部有明显回流。