全文获取类型
收费全文 | 117篇 |
免费 | 1篇 |
专业分类
公路运输 | 17篇 |
综合类 | 25篇 |
水路运输 | 23篇 |
铁路运输 | 34篇 |
综合运输 | 19篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 4篇 |
2009年 | 8篇 |
2008年 | 1篇 |
2007年 | 8篇 |
2006年 | 15篇 |
2005年 | 6篇 |
2004年 | 11篇 |
2003年 | 1篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1986年 | 2篇 |
排序方式: 共有118条查询结果,搜索用时 15 毫秒
61.
结合某高速公路沥青路面热再生工程的实际情况,测定旧沥青的常规指标、粘度及组分并与原新沥青各指标进行对比,评价旧沥青的老化程度.选择不同种类再生剂,以不同比例调配旧沥青组成再生沥青,观察再生沥青的常规指标、粘度及等性能的变化情况.试验结果表明,在旧路面的老化沥青中掺入10%~30%再生剂后,其性能得到明显的改善. 相似文献
62.
63.
64.
分布式人工智能作为人工智能与分布式计算的结合,正逐渐受到人们的重视。以城市快速路控制系统为研究背景,应用多智能体技术,以实现对其智能控制的策略。在分析研究多智能体体系架构与快速路控制系统的控制需求的基础上,进行快速路MAS的总体架构设计与层次功能设计。在分析研究Agent结构模式与构造方法的基础上,设计快速路控制协调智能体Harmony-agent的结构,并针对结构中各个模块的功能进行详细设计。MAS体系可以成为传统控制手段与智能控制方式的统一实现载体,架起了传统控制与智能控制的桥梁。MAS架构体系是兼容传统手段与智能理念的弱耦合思想的良好承载平台。 相似文献
65.
针对交通网络分布式仿真的时钟同步问题,提出了一种基于时间窗的保守性同步策略。分析对象(逻辑进程)间的关联事件,提出关联事件在进程间传递信息的延迟dij的估计方法,确定每个仿真对象的时间窗。以9个节点的示例网络为对象,实现了保守时间窗同步算法在交通网络模拟中的应用。实践表明,与其他同步算法相比这种策略具有建模容易、模拟效率高的特点。从而为满足智能运输系统中网络模拟大规模、高效率和实时动态的要求奠定了基础。 相似文献
66.
The inconsistence between system optimality and user optimality represents one of the key difficulties on network traffic congestion control. The advanced connected vehicle systems, enabling smart vehicles to possess/exchange real-time information and conduct portable computation, provide new opportunities to address this challenge. Motivated by this view, this study proposes a coordinated online in-vehicle routing mechanism with intentional information provision perturbation (CRM-IP), which seeks to shape individual vehicles online routing decisions so that user optimality and system optimality are balanced, by exploiting bounded rationality of the users. The proposed CRM-IP is modeled as a pure strategy atomic routing game, and implemented by a sequentially updating distributed algorithm. The mathematical analysis is conducted to quantify the absolute gain of system optimality corresponding to the loss of user optimality resulting from a given level of the information perturbation in the worst case so that the efficiency of the information perturbation can be evaluated. Furthermore, numerical experiments conducted based on City of Sioux Falls network investigate the average effects of the CRM-IP on system optimality and user optimality under various network traffic conditions, comparing to the CRM developed by Du et al. (in press). The results indicate that the improvement of system optimality and the reduction of individual vehicles’ travel time from the CRM is more significant when the network traffic is under an mild congestion state, such as under the levels of service (LOS’s) C, D, and E, rather than under extremely sparse or congested states, such as under LOS’s A and B, or F. Moreover, higher level of information perturbation benefits system optimality more, but the marginal effect decreases after the perturbation reaching certain level, such as in this case study. In addition, a portion of vehicles may sacrifice user optimality due to the information perturbation, but the extent of the sacrifice is not significant, even though it increases with the information perturbation level. Hence, a small information perturbation is recommended to achieve an efficient network traffic control through the CRM-IP. Overall, this study proposes the CRM-IP as an efficient routing mechanism, which has a great potential to guide the routing decisions of individual vehicles so that their collective behavior improve network performance in both system optimality and user optimality. 相似文献
67.
职业卫生服务的各个环节,如评价、监测、治理技术、生物监测以及健康监护、职业病诊断等,都与毒源的辨识密切相关。准确辨识毒物是有的放矢地作好职业卫生服务必不可少的基本技能,尤其是近些年隐匿性职业中毒频频出现,更显出毒源辨识的重要性。 相似文献
68.
69.
70.
Vehicular Ad-Hoc Networks (VANETs) are an emerging technology soon to be brought to everyday life. Many Intelligent Transport Systems (ITS) services that are nowadays performed with expensive infrastructure, like reliable traffic monitoring and car accident detection, can be enhanced and even entirely provided through this technology. In this paper, we propose and assess how to use VANETs for collecting vehicular traffic measurements. We provide two VANET sampling protocols, named SAME and TOME, and we design and implement an application for one of them, to perform real time incident detection. The proposed framework is validated through simulations of both vehicular micro-mobility and communications on the 68 km highway that surrounds Rome, Italy. Vehicular traffic is generated based on a large real GPS traces set measured on the same highway, involving about ten thousand vehicles over many days. We show that the sampling monitoring protocol, SAME, collects data in few seconds with relative errors less than 10%, whereas the exhaustive protocol TOME allows almost fully accurate estimates within few tens of seconds. We also investigate the effect of a limited deployment of the VANET technology on board of vehicles. Both traffic monitoring and incident detection are shown to still be feasible with just 50% of equipped vehicles. 相似文献