In this paper,we carry out an analysis of the structural properties of the solutions to the speed gradient(SG)traffic flow model.Under the condition that the relaxation effect can be neglected,it is shown that a 1-sho...In this paper,we carry out an analysis of the structural properties of the solutions to the speed gradient(SG)traffic flow model.Under the condition that the relaxation effect can be neglected,it is shown that a 1-shock or a 1-rarefaction is associated with the first characteristic,but on the other hand,a contact discontinuity rather than a 2-shock or a 2-rarefaction is associated with the second characteristic.Since the existence of a 2-shock or 2-rarefaction violates the physical mechanism of the traffic flow,the SG model is more reasonable.If the relaxation effect cannot be neglected,it is somewhat difficult to carry out the analytical analysis and the numerical simulation results should be obtained.展开更多
在复杂轨道交通网络中,某些乘客的出行行程是确定的。这些乘客可以作为启发式的“证人”,为其他乘客证明某个行程的可能性,从而在保证查全率的前提下,准确地找出潜在的密接乘客。本文的目的是开发一套适用于城市轨道交通的疫情密接人群...在复杂轨道交通网络中,某些乘客的出行行程是确定的。这些乘客可以作为启发式的“证人”,为其他乘客证明某个行程的可能性,从而在保证查全率的前提下,准确地找出潜在的密接乘客。本文的目的是开发一套适用于城市轨道交通的疫情密接人群追溯方法,利用有限的确定行程乘客作为虚拟的目击者,采用启发式的树搜索生成目标乘客可能的出行链,通过验证目标出行链与感染者行程是否有交集,判断目标乘客是否为密接乘客。以北京城市轨道交通为例,招募志愿者在特定线路乘车,并假定感染者乘车信息,通过提取有关自动售检票(Automatic Fare Collection,AFC)数据识别密接乘客,以验证方法的有效性。在实验场景下,本文提出的方法对密接乘客的识别查全率达到100%,查准率达到92.7%,表明方法具备一定的可行性。识别结果有助于有关部门针对性采取措施,更高效率地防范疫情蔓延和传播。展开更多
基金The project supported by the National Natural Science Foundation of China(10272101)
文摘In this paper,we carry out an analysis of the structural properties of the solutions to the speed gradient(SG)traffic flow model.Under the condition that the relaxation effect can be neglected,it is shown that a 1-shock or a 1-rarefaction is associated with the first characteristic,but on the other hand,a contact discontinuity rather than a 2-shock or a 2-rarefaction is associated with the second characteristic.Since the existence of a 2-shock or 2-rarefaction violates the physical mechanism of the traffic flow,the SG model is more reasonable.If the relaxation effect cannot be neglected,it is somewhat difficult to carry out the analytical analysis and the numerical simulation results should be obtained.
文摘在复杂轨道交通网络中,某些乘客的出行行程是确定的。这些乘客可以作为启发式的“证人”,为其他乘客证明某个行程的可能性,从而在保证查全率的前提下,准确地找出潜在的密接乘客。本文的目的是开发一套适用于城市轨道交通的疫情密接人群追溯方法,利用有限的确定行程乘客作为虚拟的目击者,采用启发式的树搜索生成目标乘客可能的出行链,通过验证目标出行链与感染者行程是否有交集,判断目标乘客是否为密接乘客。以北京城市轨道交通为例,招募志愿者在特定线路乘车,并假定感染者乘车信息,通过提取有关自动售检票(Automatic Fare Collection,AFC)数据识别密接乘客,以验证方法的有效性。在实验场景下,本文提出的方法对密接乘客的识别查全率达到100%,查准率达到92.7%,表明方法具备一定的可行性。识别结果有助于有关部门针对性采取措施,更高效率地防范疫情蔓延和传播。
