全文获取类型
收费全文 | 172篇 |
免费 | 18篇 |
专业分类
公路运输 | 46篇 |
综合类 | 62篇 |
水路运输 | 51篇 |
铁路运输 | 10篇 |
综合运输 | 21篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 9篇 |
2014年 | 18篇 |
2013年 | 10篇 |
2012年 | 17篇 |
2011年 | 21篇 |
2010年 | 16篇 |
2009年 | 14篇 |
2008年 | 7篇 |
2007年 | 10篇 |
2006年 | 2篇 |
2005年 | 6篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1992年 | 1篇 |
排序方式: 共有190条查询结果,搜索用时 15 毫秒
131.
黄正锋 《重庆交通大学学报(自然科学版)》2009,28(4):742-744
提出将路段质量定义为路段重要度(LS)和路段通行能力可靠度(LCR)的线性加权和,作为城市道路单元或公路路段关键性的衡量指标,有助于确定亟需改善的道路单元。针对路段通行能力服从连续分布函数的假设,基于Monte Carlo模拟求解随机用户均衡配流模型,从而可以通过灵敏度分析(SA)方法计算LS,使用LCR分布函数计算LCR,最终确定出随机路网的路段质量排序。以一个小型网络作为算例,验证路段质量排序的可行性。 相似文献
132.
133.
基于舰载舰壳声呐搜潜原理及舰艇协同应召螺旋搜潜战术,建立了在潜艇初始位置已知、航向及航速未知的条件下,多舰利用舰壳声呐对潜艇目标搜索的数学模型,基于已建搜索模型及假定的潜艇运动模型,采用蒙特卡洛方法,仿真分析了相同条件、不同潜艇运动模型下,潜艇初始航向角、潜艇初始航向角选定后航向变化次数、航段搜索时间、航段最佳搜索时间等因素对搜潜概率的影响,并进行了分析比较。仿真结果表明,不同目标运动态势对搜索概率均具有较大影响,在对潜艇进行搜索时,只有根据对潜艇目标运动态势的感知程度合理选择搜索模式,才能提高搜索效率。 相似文献
134.
135.
为解决在预约需求下,考虑预约时刻、时长及延时需求的共享停车分配问题,提出一种共享停车泊位分配模型. 以平台收益和停车步行距离为优化目标,将需求分为基本及延时两种情况,确定停车预约请求的分配策略. 根据模型结构,设计随机解集生成方法,利用蒙特卡洛法确定模型的最优解. 以医院停车场及周边停车场为案例,测试模型. 结果表明,模型能较好地服务于共享停车泊位的分配,实现平台收益与满足需求之间的平衡. 相似文献
136.
Accurate fatigue assessment is a challenging and crucial aspect of riser design. The prediction of the long-term fatigue damage must account for numerous sea states of different wave heights, periods, and directions. Each sea state entails a dynamic analysis, often performed in the time domain owing to the significant nonlinearities. Because of the short-term uncertainties from irregular waves, the simulation duration must be sufficiently long for results to converge. To alleviate the hefty computational cost of long-term fatigue analysis, researchers have proposed efficient methods, but these are not without drawbacks; in particular, wave directionality is commonly neglected. This paper presents an efficient method for long-term fatigue analysis based on time domain simulation, considering wave directionality among other things. The proposed method is based on an enhanced version of control variates to reduce the variance in Monte Carlo simulations (MCS). The control function is constructed by training artificial neural network (ANN) models using existing MCS data. Here, a customized scheme is developed to allow for the situation that the training data and ANN prediction cases have different wave directions. The proposed method is unbiased and provides an error estimate. Simulations are performed on a floating system, and the proposed method is found to improve the efficiency of MCS significantly. Different scenarios such as fixed and random wave directions are compared, confirming that wave directionality is critical and should be included in a long-term fatigue assessment. 相似文献
137.
This paper presents a framework for addressing uncertainty and risk for large-scale transportation investments involving public–private participation. Demand, fare/toll and demand responsive costs are considered in the uncertainty analysis. Uncertainty analysis provides information on economic feasibility of the project. A set of relaxation policies is proposed to form various Ownership, Tenure and Governance (OTG) strategies reflecting the nature and level of participation by the public and private entity. A Monte Carlo Simulation-based Value at Risk is used to quantify risk. Finally, a methodology is proposed to integrate uncertainty and risk. The framework is tested on the proposed multibillion dollar Detroit River International Crossing connecting the cities of Detroit in the USA with Windsor in Canada. The analysis provides insights to probable outcomes for this transportation infrastructure investment under different OTG scenarios. 相似文献
138.
139.
140.