A new travel time reliability-based traffic assignment model is proposed to investigate the effects of an advanced transportation information system (ATIS) on drivers' risk-taking path choice behaviours in transpo...A new travel time reliability-based traffic assignment model is proposed to investigate the effects of an advanced transportation information system (ATIS) on drivers' risk-taking path choice behaviours in transportation networks with demand uncertainty. In the model, drivers are divided into two classes. The first class is not equipped with ATIS, while the second class is equipped with ATIS. Different risk-taking path choice behaviours of the two classes are studied, respectively. A corresponding mixed equilibrium traffic assignment model is formulated as a variational inequality problem in terms of path flows, which is solved by a heuristic solution algorithm. Numerical results indicate that the ATIS can influence the drivers' risk-taking path choice behaviours and the total system travel time in transportation networks with demand uncertainty. It is also found that under higher demand levels, the benefits of ATIS for network performance enhancement may be more obvious.展开更多
The Sixth Beijing Forum on Human Rights is opened today, which is co-spon- sored by the China Society for Human Rights Studies and the China Foundation for Human Rights Development. First, on behalf of the China Found...The Sixth Beijing Forum on Human Rights is opened today, which is co-spon- sored by the China Society for Human Rights Studies and the China Foundation for Human Rights Development. First, on behalf of the China Foundation for Human Rights Development, I would like to express warm congratulations to the opening of the Forum, and heartfelt thanks tothe friends who have always cared for and supported for the development and progress of human rights cause of China.展开更多
The 2018 Beijing Forum on Human Rights opens on this wonderful autumn day.On behalf of the China Society for Human Rights Studies, I wish to express warm congratulations on the opening of the forum and a sincere welco...The 2018 Beijing Forum on Human Rights opens on this wonderful autumn day.On behalf of the China Society for Human Rights Studies, I wish to express warm congratulations on the opening of the forum and a sincere welcome to all guests from home and abroad.展开更多
在足球机器人运动过程中,足球机器人处于一个实时对抗的复杂环境中,这就需要机器人有较高的实时运动过程应对能力。需要对每个关键时刻,例如:多机器人抢球过程、单机器人控球过程等,做出合理的应对措施。许多策略的研究都只注重单机器...在足球机器人运动过程中,足球机器人处于一个实时对抗的复杂环境中,这就需要机器人有较高的实时运动过程应对能力。需要对每个关键时刻,例如:多机器人抢球过程、单机器人控球过程等,做出合理的应对措施。许多策略的研究都只注重单机器人控球过程的路径规划,没有考虑到多机器人竞争的过程,导致足球机器人整个运动过程中的一些关键步骤的缺失,丧失了完整性,忽略了实时的对抗性。拟采用新的策略解决上述问题:第一步是将采用WTA(Winner Take All)竞争模型去有效的解决多机器人竞争问题;第二步将采用一种改进的APF(Artificial Potential Field)路径规划法来进行避障。解决了传统APF算法的弊端,提高了效率。通过仿真实验,验证了理论的正确性,也验证了所提理论的科学性和实用性,为以后在其他科学领域的实践奠定了基础。展开更多
为识别复杂地形影响下香港国际机场(HKIA,Hong Kong International Airport)低空风切变的易发空域,采用大涡模拟方法(LES,large eddy simulation)对机场及其周边地形进行了风场精细化数值模拟。结合风速云图比较东、东南、南、西南风背...为识别复杂地形影响下香港国际机场(HKIA,Hong Kong International Airport)低空风切变的易发空域,采用大涡模拟方法(LES,large eddy simulation)对机场及其周边地形进行了风场精细化数值模拟。结合风速云图比较东、东南、南、西南风背景下3条跑道起降航道上的风速变化,分析得出了地形与风场分布间的因果关系。通过与无地形情况下的对照试验结果对比,采用F因子(识别逆风)和7节标准(识别侧风)识别机场跑道低空风切变易发区间。结果表明,东风易造成飞机进离场的逆风风速发生时空变化;西南风影响跑道东侧着陆路径上的逆风风速,但几乎不影响跑道西侧离场路径的风速;在东南风和南风背景下,3条跑道起降航道低空段的侧风均受地形影响显著。根据3条跑道进离场航道上的低空风切变易发空域,得到了地形因素对香港国际机场低空风切变的影响范围,研究结果可为机场风切变风险防控提供主动规避措施和建议。展开更多
基金The National High Technology Research and Development Program of China (863 Program) (No.2006AA11Z209)Youth Science and Technology Foundation of China University of Mining and Technology (No.2007A028)Natural Science Foundation of Beijing (No.9073018)
文摘A new travel time reliability-based traffic assignment model is proposed to investigate the effects of an advanced transportation information system (ATIS) on drivers' risk-taking path choice behaviours in transportation networks with demand uncertainty. In the model, drivers are divided into two classes. The first class is not equipped with ATIS, while the second class is equipped with ATIS. Different risk-taking path choice behaviours of the two classes are studied, respectively. A corresponding mixed equilibrium traffic assignment model is formulated as a variational inequality problem in terms of path flows, which is solved by a heuristic solution algorithm. Numerical results indicate that the ATIS can influence the drivers' risk-taking path choice behaviours and the total system travel time in transportation networks with demand uncertainty. It is also found that under higher demand levels, the benefits of ATIS for network performance enhancement may be more obvious.
文摘The Sixth Beijing Forum on Human Rights is opened today, which is co-spon- sored by the China Society for Human Rights Studies and the China Foundation for Human Rights Development. First, on behalf of the China Foundation for Human Rights Development, I would like to express warm congratulations to the opening of the Forum, and heartfelt thanks tothe friends who have always cared for and supported for the development and progress of human rights cause of China.
文摘The 2018 Beijing Forum on Human Rights opens on this wonderful autumn day.On behalf of the China Society for Human Rights Studies, I wish to express warm congratulations on the opening of the forum and a sincere welcome to all guests from home and abroad.
文摘在足球机器人运动过程中,足球机器人处于一个实时对抗的复杂环境中,这就需要机器人有较高的实时运动过程应对能力。需要对每个关键时刻,例如:多机器人抢球过程、单机器人控球过程等,做出合理的应对措施。许多策略的研究都只注重单机器人控球过程的路径规划,没有考虑到多机器人竞争的过程,导致足球机器人整个运动过程中的一些关键步骤的缺失,丧失了完整性,忽略了实时的对抗性。拟采用新的策略解决上述问题:第一步是将采用WTA(Winner Take All)竞争模型去有效的解决多机器人竞争问题;第二步将采用一种改进的APF(Artificial Potential Field)路径规划法来进行避障。解决了传统APF算法的弊端,提高了效率。通过仿真实验,验证了理论的正确性,也验证了所提理论的科学性和实用性,为以后在其他科学领域的实践奠定了基础。
文摘为识别复杂地形影响下香港国际机场(HKIA,Hong Kong International Airport)低空风切变的易发空域,采用大涡模拟方法(LES,large eddy simulation)对机场及其周边地形进行了风场精细化数值模拟。结合风速云图比较东、东南、南、西南风背景下3条跑道起降航道上的风速变化,分析得出了地形与风场分布间的因果关系。通过与无地形情况下的对照试验结果对比,采用F因子(识别逆风)和7节标准(识别侧风)识别机场跑道低空风切变易发区间。结果表明,东风易造成飞机进离场的逆风风速发生时空变化;西南风影响跑道东侧着陆路径上的逆风风速,但几乎不影响跑道西侧离场路径的风速;在东南风和南风背景下,3条跑道起降航道低空段的侧风均受地形影响显著。根据3条跑道进离场航道上的低空风切变易发空域,得到了地形因素对香港国际机场低空风切变的影响范围,研究结果可为机场风切变风险防控提供主动规避措施和建议。