A weighted time-based global hierarchical path planning method is proposed to obtain the global optimal path from the starting point to the destination with time optimal control. First, the grid-or graph-based modelin...A weighted time-based global hierarchical path planning method is proposed to obtain the global optimal path from the starting point to the destination with time optimal control. First, the grid-or graph-based modeling is performed and the environment is divided into a set of grids or nodes. Then two time-based features of time interval and time cost are presented. The time intervals for each grid are built, during each interval the condition of the grid remains stable, and a time cost of passing through the grid is defined and assigned to each interval. Furthermore, the weight is introduced for taking both time and distance into consideration, and thus a sequence of multiscale paths with total time cost can be achieved. Experimental results show that the proposed method can handle the complex dynamic environment, obtain the global time optimal path and has the potential to be applied to the autonomous robot navigation and traffic environment.展开更多
A theoretical study was conducted on finding optimal paths in transportation networks where link travel times were stochastic and time-dependent(STD). The methodology of relative robust optimization was applied as mea...A theoretical study was conducted on finding optimal paths in transportation networks where link travel times were stochastic and time-dependent(STD). The methodology of relative robust optimization was applied as measures for comparing time-varying, random path travel times for a priori optimization. In accordance with the situation in real world, a stochastic consistent condition was provided for the STD networks and under this condition, a mathematical proof was given that the STD robust optimal path problem can be simplified into a minimum problem in specific time-dependent networks. A label setting algorithm was designed and tested to find travelers' robust optimal path in a sampled STD network with computation complexity of O(n2+n·m). The validity of the robust approach and the designed algorithm were confirmed in the computational tests. Compared with conventional probability approach, the proposed approach is simple and efficient, and also has a good application prospect in navigation system.展开更多
Considering that non-motorized transport along with public transport are resourceful forms of mobility, this research aimed to investigate the serviceability of integrated bicycle path networks in towns of medium size...Considering that non-motorized transport along with public transport are resourceful forms of mobility, this research aimed to investigate the serviceability of integrated bicycle path networks in towns of medium size. Factors impacting bicycle use in medium sized cities （urban planning, other transport means, adequacy of installations and parking spaces, etc.） have been examined. Bicycle can be something more than a sport or entertainment activity and has the potential to become an efficient means of transport. Xanthi is a medium sized town in Northern Greece. Its total area is 153 km2 and 65,000 people live there. An analysis of the existing traffic schemes in the city has pointed out the necessity of an organized bicycle paths network both cost effective and time saving. The main characteristics of such a network are described, hoping that in its completed form could impose the features of sustainable mobility and would be a paradigm for mid-sized cities in the country. Cars could be kept out of the central part of Xanthi ifa bicycle paths network is built using a ring-like scheme, since the residents favor the use of bicycle. Local authorities＇ plans must encourage the lending of public owned bicycles.展开更多
基金Supported by the National Natural Science Foundation of China(No.61100143,No.61370128)the Program for New Century Excellent Talents in University of the Ministry of Education of China(NCET-13-0659)Beijing Higher Education Young Elite Teacher Project(YETP0583)
文摘A weighted time-based global hierarchical path planning method is proposed to obtain the global optimal path from the starting point to the destination with time optimal control. First, the grid-or graph-based modeling is performed and the environment is divided into a set of grids or nodes. Then two time-based features of time interval and time cost are presented. The time intervals for each grid are built, during each interval the condition of the grid remains stable, and a time cost of passing through the grid is defined and assigned to each interval. Furthermore, the weight is introduced for taking both time and distance into consideration, and thus a sequence of multiscale paths with total time cost can be achieved. Experimental results show that the proposed method can handle the complex dynamic environment, obtain the global time optimal path and has the potential to be applied to the autonomous robot navigation and traffic environment.
基金Project(71001079)supported by the National Natural Science Foundation of China
文摘A theoretical study was conducted on finding optimal paths in transportation networks where link travel times were stochastic and time-dependent(STD). The methodology of relative robust optimization was applied as measures for comparing time-varying, random path travel times for a priori optimization. In accordance with the situation in real world, a stochastic consistent condition was provided for the STD networks and under this condition, a mathematical proof was given that the STD robust optimal path problem can be simplified into a minimum problem in specific time-dependent networks. A label setting algorithm was designed and tested to find travelers' robust optimal path in a sampled STD network with computation complexity of O(n2+n·m). The validity of the robust approach and the designed algorithm were confirmed in the computational tests. Compared with conventional probability approach, the proposed approach is simple and efficient, and also has a good application prospect in navigation system.
文摘Considering that non-motorized transport along with public transport are resourceful forms of mobility, this research aimed to investigate the serviceability of integrated bicycle path networks in towns of medium size. Factors impacting bicycle use in medium sized cities （urban planning, other transport means, adequacy of installations and parking spaces, etc.） have been examined. Bicycle can be something more than a sport or entertainment activity and has the potential to become an efficient means of transport. Xanthi is a medium sized town in Northern Greece. Its total area is 153 km2 and 65,000 people live there. An analysis of the existing traffic schemes in the city has pointed out the necessity of an organized bicycle paths network both cost effective and time saving. The main characteristics of such a network are described, hoping that in its completed form could impose the features of sustainable mobility and would be a paradigm for mid-sized cities in the country. Cars could be kept out of the central part of Xanthi ifa bicycle paths network is built using a ring-like scheme, since the residents favor the use of bicycle. Local authorities＇ plans must encourage the lending of public owned bicycles.
