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501.
为了提高交通基础设施BOT项目管理水平,基于交通基础设施BOT项目的界面信息特点,指出了对该类项目进行界面管理的必要性。提出应从技术分析、组织体系和合同约束等角度,分析该类项目在全生命周期中存在的界面,探讨了界面管理在交通基础设施BOT项目的具体应用。 相似文献
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紧凑、轻巧、价格低廉是葫芦起重机的最大优点,在分析几种调速与控制方案的基础上,指出变频调速技术的应用,可以克服葫芦起重机使用中的一些缺点;随着变频技术的迅速发展,其系统价格及性价比的优势愈来愈显著,变频葫芦桥式起重机、变频葫芦门式起重机将会以极大的优势占领市场。 相似文献
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Mixed-effects models,also called random-effects models,are a regression type of analysis which enables the analyst to not only describe the trend over time within each subject,but also to describe the variation among different subjects.Nonlinear mixed-effects models provide a powerful and flexible tool for handling the unbalanced count data.In this paper,nonlinear mixed-effects models are used to analyze the failure data from a repairable system with multiple copies.By using this type of models,statistical inferences about the population and all copies can be made when accounting for copy-to-copy variance.Results of fitting nonlinear mixed-effects models to nine failure-data sets show that the nonlinear mixed-effects models provide a useful tool for analyzing the failure data from multi-copy repairable systems. 相似文献
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Objective: Vehicle-to-vehicle (V2V) communication has become one of the most active fields of research recently. The implementation of the wireless connected vehicles has widely extended the transmission range of warning messages to inform drivers of hazards ahead. The present study addressed the human component with mathematical modeling of the human reaction time to warning messages in the connected vehicle systems (CVSs) with different confidence intervals (CIs). Methods: In the present study, human performance in warning responses is modeled by extending an existing mathematical model of human performance with the complexity level of tasks. The modeling of human performance with different levels of uncertainty is integrated to propose the warning message notification model in the CVS settings. The warning message notification models were proposed to model the CVSs parameters including maximum available message notification delay, the maximum available machine processing time, the minimum acceptable message notification range, and the designed message display delay. Results: The optimal designs of CVSs parameters were presented in general and for specific conditions by applying the modeling of human performance with different CIs (i.e., 95% and 99% CI) and the warning message notification model with human in the loop. A software interface with the message notification model implemented was presented to discuss the practical benefits of the current work in the design of CVSs. 相似文献
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Nak-Tak Jeong Maosen Wang Sehoon Yoo Weon-Kyong Kim Seok-Youn Han Ho-Yong Lee Myung-Won Suh 《International Journal of Automotive Technology》2017,18(3):523-533
Train-tram railway vehicles implement the connection between urban tramlines and the surrounding railway network. Train-tram railway vehicles, which use existing infrastructure, can help to avoid large investments in new railways or tramlines and make interchanges between city center and surrounding cities unnecessary. However, present train-tram rail vehicle cannot carry out the integration of operating by means of high speed in intercity railways with operating on small radius of curvature in inner city tramlines. This paper aims to develop a new model for solid wheelsets train-tram railway vehicles, which will not only pass the curve of 25mR radius of curvature traveling on inner city tramlines with the speed of 18 km/h, but also can travel on straight railway with 200 km/h high speed between intercity. In this paper, a new train-tram model, including five car-body and five motor bogies with ten traction motors, is addressed. Expect as a real rail vehicle testing, this study prefer virtual simulation, which is an effective way to show the rail vehicle performance, such as ride stability, ride comfort and ride safety, by means of evaluating the dynamic characteristics of rail vehicle. Moreover, Design of Experiment (DOE) method is used to optimize solid wheelsets bogie system on improving passenger comfort, safety and stability of train-tram. Parameters of components of bogie system are tuned to minimize the derailment coefficient and the ride comfort index. The results shows that the best comfort index for passenger and minimum derailment coefficient are found. The results also show that this optimized new train-tram model is reliable and practical enough to be applied on real rail vehicle design. 相似文献
510.
SangHyuk Yoo Jaehyeok Doh Juhee Lim Ohsung Kang Jongsoo Lee Keonwook Kang 《International Journal of Automotive Technology》2017,18(4):625-630
This study shows topology optimization of lower control arm (LCA), made of carbon fiber reinforced plastic (CFRP), that was originally composed of aluminum alloy. By mean-field homogenization (MFH) method, averaged mechanical properties of CFRP are applied to FEM analyses of 3D LCA model. The design target is to reduce the LCA weight while satisfying the multiple constraints including required stiffness and durability conditions at the same time. As a result, authors propose the new design of CFRP LCA with 30 % weight reduction compared to Al alloy LCA. 相似文献