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971.
汽车安全带安全气囊的新发展 总被引:2,自引:0,他引:2
简要回顾了汽车安全带、安全气囊的发展历史,对汽车安全带、安全气囊的发展动向作了重点介绍。基于目前国内外在该领域的差距,提出了一些应对策略。 相似文献
972.
973.
目前,世界各国都认识到在开发应用卫星导航系统的同时,必须继续发展陆基无线电导航系统。因此,我国在大力发展双星导航系统(RDSS)的同时,还应继续加强LORAN—C系统的的研究,积极开发RDSS/LORAN—C组合导航的潜力。本文对RDSS/LORAN—C组合导航的优势和可实现性进行了分析,提出了三种不同的数据组合方法,并给出了这三种方法性能的简单比较。 相似文献
974.
975.
A dual control approach for repeated anticipatory traffic control with estimation of network flow sensitivity
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This paper investigates a strategic signal control, which anticipates travelers' route choice response and determines signal timings to optimize network‐wide objectives. In general traffic assignment models are used for anticipating this route choice response. However, model‐reality mismatch usually brings suboptimal solutions to the real system. A repeated anticipatory control resolves the suboptimality and addresses the modeling error by learning from information on model bias. This paper extends the repeated control approach and focuses on the estimation of flow sensitivity as well as its influence on control, which is a crucial issue in implementation of model bias correction. The main objective of this paper is first to analyze the estimation error in the real flow derivative that is estimated from noisy measurements. A dual control method is then presented, improving both optimization objective function and derivative estimation during the control process. The proposed dual algorithm is tested on a simple network as well as on a midsize network. Numerical examples confirm the reliable performance of the new reality‐tracking control strategy and its ability to identify (local) optimal solutions on real traffic networks. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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977.
Efficient numerical schemes were presented for the steady state solutions of towed marine cables. For most of towed systems, the steady state problem can be resolved into two-point boundary-value problem, or initial value problem in some special cases where the initial values are available directly. A new technique was proposed and attempted to solve the two-point boundary-value problem rather than the conventional shooting method due to its algorithm complexity and low efficiency. First, the boundary conditions are transformed into a set of nonlinear governing equations about the initial values, then bisection method is employed to solve these nonlinear equations with the aid of 4th order Runge-Kutta method. In common sense, non-uniform (sheared) current is assumed, which varies in magnitude and direction with depth. The schemes are validated through the DE Zoysa's example, then several numerical examples are also presented to illustrate the numerical schemes. 相似文献
978.
中国首批第三代越野汽车东风"猛士"的开发 总被引:1,自引:0,他引:1
东风汽车公司通过在设计思想、设计理论与方法、技术和产品等方面的创新,完成了我国首批第三代越野汽车--东风"猛士"的开发,其整体技术性能达到国际领先水平. 相似文献
979.
980.
Optimization of headways with stop‐skipping control: a case study of bus rapid transit system
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Bus rapid transit system is designed to provide high‐quality and cost‐efficient passenger transportation services. In order to achieve this design objective, effective scheduling strategies are required. This research aims at improving the operation efficiency and service quality of a BRT system through integrated optimization of its service headways and stop‐skipping strategy. Based on cost analysis for both passengers and operation agencies, an optimization model is established. A genetic algorithms based algorithm and an application‐oriented solution method are developed. Beijing BRT Line 2 has been chosen as a case study, and the effectiveness of the optimal headways with stop‐skipping services under different demand levels has been analyzed. The results has shown that, at a certain demand level, the proposed operating strategy can be most advantageous for passengers with an accepted increase of operating costs, under which the optimum headway is between 3.5 and 5.5 min for stop‐skipping services during the morning peak hour depending on the demand with the provision of stop‐skipping services. The effectiveness of the optimal headways with stop‐skipping services is compared with those of existing headways and optimal headways without stop‐skipping services. The results show that operating strategies under the optimal headways with stop‐skipping services outperforms the other two operating strategies with respect to total costs and in‐vehicle time for passengers. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献