全文获取类型
收费全文 | 250篇 |
免费 | 14篇 |
专业分类
公路运输 | 50篇 |
综合类 | 69篇 |
水路运输 | 76篇 |
铁路运输 | 21篇 |
综合运输 | 48篇 |
出版年
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 17篇 |
2019年 | 11篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 18篇 |
2013年 | 17篇 |
2012年 | 13篇 |
2011年 | 21篇 |
2010年 | 14篇 |
2009年 | 14篇 |
2008年 | 14篇 |
2007年 | 16篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1994年 | 2篇 |
排序方式: 共有264条查询结果,搜索用时 93 毫秒
61.
影响汽车油耗的因素很多,在汽车油耗测试中,人们常会对测量结果是否有效、可信或测量的品质提出疑问,将不确定度评定应用于汽车燃油消耗量的测量中可解决上述问题。 相似文献
62.
在城市交通网络中,每个交通小区的交通发生量以及吸引量与其经济发展水平、土地利用、人口数量等因素密切相关,通常能够较为准确的预测,而小区之间的交通需求很难准确的预测. 本文假定所有起讫点的交通发生量和吸引量是确定的,而OD需求不确定且属于一个有界区间,利用鲁棒优化的方法建立OD需求不确定环境下考虑用户均衡约束的交通网络设计极小极大模型,并提出了灵敏度分析结合相继平均法(MSA)的求解算法. 数值算例表明,利用鲁棒优化方法得到的网络设计方案较传统的确定性网络设计方案具有更高的可靠性. 相似文献
63.
64.
Robust optimization for emergency logistics planning: Risk mitigation in humanitarian relief supply chains 总被引:1,自引:0,他引:1
Aharon Ben-Tal Byung Do Chung Supreet Reddy Mandala Tao Yao 《Transportation Research Part B: Methodological》2011,45(8):1177-1189
This paper proposes a methodology to generate a robust logistics plan that can mitigate demand uncertainty in humanitarian relief supply chains. More specifically, we apply robust optimization (RO) for dynamically assigning emergency response and evacuation traffic flow problems with time dependent demand uncertainty. This paper studies a Cell Transmission Model (CTM) based system optimum dynamic traffic assignment model. We adopt a min–max criterion and apply an extension of the RO method adjusted to dynamic optimization problems, an affinely adjustable robust counterpart (AARC) approach. Simulation experiments show that the AARC solution provides excellent results when compared to deterministic solution and sampling based stochastic programming solution. General insights of RO and transportation that may have wider applicability in humanitarian relief supply chains are provided. 相似文献
65.
Chao ZhangXiaojun Chen Agachai Sumalee 《Transportation Research Part B: Methodological》2011,45(3):534-552
Various models of traffic assignment under stochastic environment have been proposed recently, mainly by assuming different travelers’ behavior against uncertainties. This paper focuses on the expected residual minimization (ERM) model to provide a robust traffic assignment with an emphasis on the planner’s perspective. The model is further extended to obtain a stochastic prediction of the traffic volumes by the technique of path choice approach. We show theoretically the existence and the robustness of the ERM solution. In addition, we employ an improved solution algorithm for solving the ERM model. Numerical experiments are carried out to illustrate the characteristics of the proposed model, by comparing with other existing models. 相似文献
66.
Quantifying the benefit of responsive pricing and travel information in the stochastic congestion pricing problem 总被引:1,自引:0,他引:1
Lauren M. Gardner Stephen D. Boyles 《Transportation Research Part A: Policy and Practice》2011,45(3):204-218
This paper is concerned with roadway pricing amidst the uncertainty which characterizes long-term transportation planning. Uncertainty is considered both on the supply-side (e.g., the effect of incidents on habitual route choice behavior) and on the demand-side (e.g., due to prediction errors in demand forecasting). The framework developed in this paper also allows the benefits of real-time travel information to be compared directly against the benefits of responsive pricing, allowing planning agencies to identify the value of these policy options or contract terms in publicly-operated toll roads. Specifically, six scenarios reflect different combinations of policy options, and correspond to different solution methods for optimal tolls. Demonstrations are provided on both the Sioux falls and Anaheim networks. Results indicate that providing information to drivers implemented alongside responsive tolling may reduce expected total system travel time by over 9%, though more than 8% of the improvement is due to providing information, with the remaining 1% improvement gained from responsive tolling. 相似文献
67.
船闸通过能力与日平均过闸次数、一次过闸吨位、年通航天数、船舶装载系数以及运量不均衡系数有关,在船闸运营过程中这些因素都存在一定的不确定性,对船闸通过能力的计算产生很大的影响。为消除不确定性因素的影响,采用基于MC法的计算机仿真研究船闸通过能力,并以新夏港河船闸年过闸货运量作为研究对象予以说明。运行结果表明,计算机仿真能够较好地应对不确定性问题,为船闸工程建设中船闸通过能力计算提供理论依据。 相似文献
68.
69.
为解决全断面岩石掘进机(TBM)刀盘系统由于掘进过程中工况不确定性造成的载荷不确定和动态特性预测难度大的问题,提出一种工况不确定性的动力学分析方法。首先,对4种典型掘进工况进行等效,采用区间理论将不同工况的等效载荷进行区间表示,并将工况的不确定性转化为载荷的不确定性; 然后,通过集中质量法建立刀盘多自由度耦合动力学模型,并结合得到的区间不确定载荷等效出不确定工况下的多自由度耦合动力学模型,求解得到不确定工况下的动力学响应; 最后,以现场实测数据对该方法进行验证。研究结果表明: TBM在设计时应充分考虑工况的差异性; 随着刀盘分块的增多,刀盘系统稳定性有所提高; 驱动齿轮均匀分布时,刀盘系统振动稳定性较好。 相似文献
70.
This paper revisits the real option investment problem from a ‘Knightian’ perspective of uncertainty. We examine the decision to invest in rail transit infrastructure (i.e., transport improvement) by treating population scale and the attitudes of decision-makers or social planners as sources of risk and ambiguity. An α-maxmin multiple-priors expected utility framework is developed to solve for the option value of rail transit investment under Knightian uncertainty. We find that the threshold for investment varies with the ambiguity attitudes (i.e., pessimism or optimism) of decision-makers regarding future population dynamics, and show that option value can in fact either increase or decrease with uncertainty subject to κ-ignorance and ambiguity. We also underline the effect of transport improvement on traffic congestion under various states of nature, and determine the specific population scale ranges for which investment is warranted under (1) risk and (2) Knightian uncertainty. These dynamics are illustrated in a numerical application adapted from a Chinese rail transit initiative specific to the Xiamen region. 相似文献