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This paper is concerned with the connection design for a two-floating beam system for minimum hydroelastic response. The frequency domain approach is used for the hydroelastic analysis. The fluid is modelled as an ideal fluid, and the floating beams are modelled by the Euler–Bernoulli beam theory. The boundary element method (BEM) and the finite element method (FEM) are applied to solve the governing equation of the fluid motion and the beam equation of motion, respectively. The study aims to investigate the optimum location and rotational stiffness of the connection for the two-floating beam system with the view to minimize the compliance. The study also investigates the effects of relative beam stiffnesses on the hydroelastic response of the two-floating beam system. 相似文献
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Are Intelligent Transportation Systems (ITS) affecting transportation industry only? ITS are currently perceived as a contribution to transportation industry only; however, by quantitatively analyzing the economic impact of ITS on the state of Michigan, this work attempts to answer the posed question. The quantitative economic analysis is carried out through the well‐established Leontief's Input–Output (I‐O) model. This model is employed to establish ITS effects on each industry by detailing RIMS II I‐O tables for Michigan constructed from the national I‐O tables. Major savings by ITS identified as reduced time delays and fuel cost savings are quantitatively simulated thereby generating an overall cost reduction factor which is incorporated in Michigan I‐O tables to modify their characteristics. ITS impact on each industry in I‐O tables is achieved by maximizing effects on certain selected industries. Impact multipliers that are customary macro‐economic measures for I‐O analysis are then calculated for all the aggregated industries. Multipliers comparison for the three cases namely before ITS implementation, conventional improvement methods, and after ITS implementation is evaluated. These values suggest greater economic benefits that may be achieved by statewide implementation of the ITS. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Motorised vehicle conditions have been evaluated by many researchers. In contrast, there are very limited studies on vulnerable and non-motorised users, such as cyclists and pedestrians, specifically children, the elderly and the disabled. Thus, this paper reviews prominent studies on street evaluations to identify effective indicators for non-motorised trips. The street condition for these trips is measured by the bicycle level of service (BLOS) and the pedestrian level of service (PLOS). In previous studies, different methods have been introduced for PLOS and BLOS. However, these methods have several major shortcomings. First, pedestrians and cyclists are assumed to be users who can share street facilities with motorised vehicles and thus are considered equivalent to cars. Second, the majority of these methods are complicated and time-consuming, and it is difficult to connect them to a design process. Furthermore, these methods support only a limited number of walking and cycling facilities; therefore, they may not be valid for a wide range of pedestrians and cyclists with a diverse variety of abilities and ages. This study discusses the challenges in the BLOS and PLOS research and attempts to introduce new objectives for further studies in this field to eliminate the aforementioned shortcomings. 相似文献
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采用互信息来描述图像配准的效果,应用类电磁机制优化算法搜索配准所对应的空间变换参数,并借鉴POWELL优化算法,在局部搜索过程中采用了黄金分割点一维搜索方法进行搜索,实验结果表明提出的算法可以很好的脱离局部最优解,同时可以达到较好的配准精度,并具有较好的时效性。 相似文献
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Muhammad Marizwan Abdul Manan András Várhelyi Ali Kemal Çelik Hizal Hanis Hashim 《国际交通安全学会研究报告》2018,42(4):207-220
This study aims to determine risk factors contributing to traffic crashes in 9,176 fatal cases involving motorcycle in Malaysia between 2010 and 2012. For this purpose, both multinomial and mixed models of motorcycle fatal crash outcome based on the number of vehicle involved are estimated. The corresponding model predicts the probability of three fatal crash outcomes: motorcycle single-vehicle fatal crash, motorcycle fatal crash involving another vehicle and motorcycle fatal crash involving two or more vehicles. Several road characteristic and environmental factors are considered including type of road in the hierarchy, location, road geometry, posted speed limit, road marking type, lighting, time of day and weather conditions during the fatal crash. The estimation results suggest that curve road sections, no road marking, smooth, rut and corrugation of road surface and wee hours, i.e. between 00.00 am to 6 am, increase the probability of motorcycle single-vehicle fatal crashes. As for the motorcycle fatal crashes involving multiple vehicles, factors such as expressway, primary and secondary roads, speed limit more than 70 km/h, roads with non-permissible marking, i.e. double lane line and daylight condition are found to cause an increase the probability of their occurrence. The estimation results also suggest that time of day (between 7 pm to 12 pm) has an increasing impact on the probability of motorcycle single-vehicle fatal crashes and motorcycle fatal crashes involving two or more vehicles. Whilst the multinomial logit model was found as more parsimonious, the mixed logit model is likely to capture the unobserved heterogeneity in fatal motorcycle crashes based on the number of vehicles involved due to the underreporting data with two random effect parameters including 70 km/h speed limit and double lane line road marking. 相似文献
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中巴公路穿越西喀喇昆仑-喜马拉雅山系的冰缘地带,沿线冰川活跃,冰川消融与进退等引发各类地质灾害,严重损毁公路,危及公路安全.中巴公路灾害防治是中巴公路改扩建工程的目标,科学防灾减灾需要掌握中巴公路沿线冰川及冰川灾害的形成及发展规律.通过野外调查、定点观测、文献检索与遥感解译等研究手段发现,独特的地形地貌、丰沛的夏季降雪、险峻的地形落差、山地气候波动等环境因素孕育大量跃动型冰川,具有长期萎缩与间歇跃动、同期不同步、夏季累积型和悬冰川的活动特征.中巴公路沿线可区分为四大活动性冰川群,洪扎河谷(Hunza River)一带的帕苏幕士塔格山冰川群(Pasu Mustaghs)最为活跃.中巴公路冰川灾害可分为冰川灾害与冰川地质灾害两大类别,10个类型.其中,冰湖溃决、冰川泥石流的治理是工程上主要面临的防治问题. 相似文献
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Irawan Muhammad Zudhy Belgiawan Prawira Fajarindra Tarigan Ari Krisna Mawira Wijanarko Fajar 《Transportation》2020,47(5):2367-2389
Transportation - In the last decade, the emergence of ride-sourcing services has transformed personal trip behavior. In the context of Indonesia, ride-sourcing services have evolved into two modes... 相似文献
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Jamshaid Ali Muhammad Ushaq Salman Majeed 《Journal of Marine Science and Technology》2012,17(3):340-348
The strapdown inertial navigation system (SINS) is able to provide continuous estimates of a vehicle??s velocity, position and attitude. As a rule, the SIMS component known as a high accuracy strapdown inertial measurement unit (SIMU) is an exceptionally expensive system. Less expensive SIMUs comprised of low cost sensors suffer from degraded performance, but this can be compensated for, in part, by addition of a velocity data recorder (VDR) to accompany the SINS. In this configuration, the need frequently arises to align the SINS of a submarine to in order to avoid a long run-up of the inertial system before a start command is issued. This in-motion alignment (IMA) can be accomplished by integrating SINS data with some external aiding source, such as the VDR, by using some form of measurement matching method. Accordingly, this paper demonstrates a consistent IMA scheme for a low-cost SIMU using a robust Kalman/ $ H_{\infty } $ filter structure. An error model of the SINS is derived in which the state vector includes attitude, velocity, position and sensor errors. Velocity information from the VDR is used as a measurement to the proposed filter. All significant equations concerning navigation are presented in conjunction with argument. Results show the advantages of the approach and emphasize diverse aspects of the SINS. 相似文献
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