With the development of satellite communication,in order to solve the problems of shortage of on-board resources and refinement of delay requirements to improve the communication performance of satellite optical netwo...With the development of satellite communication,in order to solve the problems of shortage of on-board resources and refinement of delay requirements to improve the communication performance of satellite optical networks,this paper proposes a bee colony optimization algorithm for routing and wavelength assignment based on directional guidance(DBCO-RWA)in satellite optical networks.In D-BCORWA,directional guidance based on relative position and link load is defined,and then the link cost function in the path search stage is established based on the directional guidance factor.Finally,feasible solutions are expanded in the global optimization stage.The wavelength utilization,communication success probability,blocking rate,communication hops and convergence characteristic are simulated.The results show that the performance of the proposed algorithm is improved compared with existing algorithms.展开更多
This paper describes a cooperative decentralized architecture for reactive real-time route guidance. The architecture is cooperative in the sense that it allows adjacent local controllers to exchange information regar...This paper describes a cooperative decentralized architecture for reactive real-time route guidance. The architecture is cooperative in the sense that it allows adjacent local controllers to exchange information regarding the traffic conditions in their territories. A set of local decision rules and associated heuristic functions to support the cooperative architecture are specified. A protocol governing the knowledge exchange among local adjacent controllers is developed. A simulation-assignment modeling framework is used for assessing the effectiveness of this cooperative architecture under various levels of controller knowledge and network traffic congestion. The cooperative decentralized system is tested under various scenarios of knowledge and cooperation and network traffic demand levels. The cooperative system is compared against the shortest path algorithm as a benchmark.展开更多
Haptic(vibration)information expression is an effective human-computer interaction mode and information transfer method.It makes up shortcomings of sound under certain conditions and is an important channel of informa...Haptic(vibration)information expression is an effective human-computer interaction mode and information transfer method.It makes up shortcomings of sound under certain conditions and is an important channel of information transfer for route guidance field.As a special kind of walkers,the visually impaired pedestrians have a specific type of cognition or perception of route guidance environment(including spatial orientation,distance and walking speed etc.)and they have sharp sense of touch resources form the ordinary.This work integrated application of GPS,GIS and Haptic(vibration)technology to develop more reliable mode route guidance for the visually impaired.It provides different vibration to the user under two circumstances:key nodes of roads ahead and deviation planning path.It resists environmental noise,reflects timely and has high effectiveness.Based on Google Legend phone,we developed the prototype and realized the designed functions,and verified the effectiveness of the system.We initially determined the thresholds of deviating from the path,those at road junctions and other nodes through experiments,interviews etc.And we used the thresholds for experiments testing and guiding.Then they were inspected,corrected and improved in the field practice.Finally,more reasonable thresholds were drawn out for future applications in reality.展开更多
In order to increase the aircraft's survival in the flight mission, it is necessary to carry out flight mission planning, which includes TF/TA2( terrain following/terrain avoidance/threat avoidance). An approach to...In order to increase the aircraft's survival in the flight mission, it is necessary to carry out flight mission planning, which includes TF/TA2( terrain following/terrain avoidance/threat avoidance). An approach to 3D-route planning based on A * heuristic search algorithm was selected to determine the routes of fiber optic guidance missile' s cruise segment. The cost function was discussed, which was mainly related to the physical obstacle, threat exposure, and aircraft performance characteristics. The digital map techniques were presented, which included setting "no-go" area according to fiber's safety requirement. The optimal or the sub-optimal route was obtained, while the cost function constraints were satisfied and the stored terrain obtained from a real terrain was digitized. The algorithm is validated through simulation and can fulfill the route planning task which focuses on the cruise segment of fiber optic guidance missile.展开更多
Optimal route selection is an important function of vehicle trac flow guidance system. Its core is to determine the index weight for measuring the route merits and to determine the evaluation method for selecting rout...Optimal route selection is an important function of vehicle trac flow guidance system. Its core is to determine the index weight for measuring the route merits and to determine the evaluation method for selecting route. In this paper, subjective weighting method which relies on driver preference is used to determine the weight and the paper proposes the multi-criteria weighted decision method based on vague sets for selecting the optimal route. Examples show that, the usage of vague sets to describe route index value can provide more decision-making information for route selection.展开更多
Formation control of fixed-wing aerial vehicles is an important yet rarely addressed problem because of their complex dynamics and various motion constraints,such as nonholonomic and velocity constraints.The guidance-...Formation control of fixed-wing aerial vehicles is an important yet rarely addressed problem because of their complex dynamics and various motion constraints,such as nonholonomic and velocity constraints.The guidance-route-based strategy has been demonstrated to be applicable to fixed-wing aircraft.However,it requires a global coordinator and there exists control lag,due to its own natures.For this reason,this paper presents a fully distributed guidance-route-based formation approach to address the aforementioned issues.First,a hop-count scheme is introduced to achieve distributed implementation,in which each aircraft chooses a neighbor with the minimum hop-count as a reference to generate its guidance route using only local information.Next,the model predictive control algorithm is employed to eliminate the control lag and achieve precise formation shape control.In addition,the stall protection and collision avoidance are also considered.Finally,three numerical simulations demonstrate that our proposed approach can implement precise formation shape control of fixed-wing aircraft in a fully distributed manner.展开更多
Walking,as the main mode of soft mobility,has become an integral aspect of urban tourism.The development of pedestrian tourist routes plays a crucial role in enhancing the positive walking experience in urban tourist ...Walking,as the main mode of soft mobility,has become an integral aspect of urban tourism.The development of pedestrian tourist routes plays a crucial role in enhancing the positive walking experience in urban tourist destinations.This research employs a hybrid multi-criteria decision-making(MCDM)with GIS to rank street segments,establishing walking-oriented tourist paths in Shiraz’s historic district,Iran.The initial steps involve identifying pivotal criteria through literature reviews and expert surveys.The Analytical Hierarchy Process(AHP)establishes criteria and sub-criteria weights using input from 30 experts.The Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)then prioritizes street segments based on sub-criteria such as traffic safety,image ability and heritage assets,security,land use and activity,accessibility,comfort and convenience,and human scale.Furthermore,a Space Syntax analysis(SSA)is conducted to evaluate the morphology of the street network in the study area and identify streets with potential for pedestrian movement.By integrating these analyses,a prime corridor for a pedestrian tourist route is identified.This study offers planners and policymakers a valuable tool for pre-investment decision-making,aiding the promotion of walkability in tourist-centric areas.展开更多
In recent years,formation control of multi-agent has been a significant research subject in the field of cooperative control.However,previous works have mainly concentrated on formation control for simple point-mass m...In recent years,formation control of multi-agent has been a significant research subject in the field of cooperative control.However,previous works have mainly concentrated on formation control for simple point-mass model and linear model.In contrast,this paper presents a novel cooperative algorithm for multiple air vehicles formation control,which aims to devise a control strategy based on guidance route to achieve precisely coordinated formation control for a group of fixed-wing aircraft in a complex task environment.The proposed method introduces the leader-follower structure for effective organization of the multi-agent coordination.Moreover,the Partial Integrated Formation and Control(PIFC)is adopted to design the control law for Guidance-Route based Formation Control(GRFC).Additionally,the proposed approach designs two guidance-route generation strategies for two special situations to demonstrate the effectiveness of GRFC in complex task environments.Theoretical analysis reveals that the proposed control protocol for guidance command can ensure the overall stability and tracking accuracy of the system.Numerical simulations are performed to illustrate the theoretical results,and verify that the proposed approach can achieve coordinated formation control precisely in a complex task environment.展开更多
运营突发事件下,向城市轨道交通(城轨)乘客有针对性地发布诱导信息,是实现高效疏导、确保城轨运营安全的重要举措。本文考虑乘客异质性,开展突发事件下城轨诱导信息发布策略研究。首先,基于潜在分类模型(Latent Class Model,LCM)构建城...运营突发事件下,向城市轨道交通(城轨)乘客有针对性地发布诱导信息,是实现高效疏导、确保城轨运营安全的重要举措。本文考虑乘客异质性,开展突发事件下城轨诱导信息发布策略研究。首先,基于潜在分类模型(Latent Class Model,LCM)构建城轨乘客在突发事件和诱导信息双重作用下的路径选择行为模型,分析乘客对诱导信息接受程度及路径选择偏好的差异。其次,以线网乘客总出行时间和线网客流分布均衡性基尼系数为优化目标,构建基于路径选择行为分析的信息诱导优化模型,并应用非支配排序遗传算法(Non-dominated Sorting Genetic AlgorithmⅡ,NSGA-Ⅱ)求解,以获得突发事件下受影响起讫点(Origin and Destination,OD)间各有效路径的最优推荐指数。最后,以北京市工作日早高峰城轨区域线网进行案例分析。结果表明:城轨乘客在突发事件下对诱导信息存在“诱导服从型”“诱导中立型”“诱导无视型”这3类不同接受程度的群体。提供诱导信息后,线网乘客总出行时间减少3.906%,线网客流分布均衡性基尼系数下降4.063%,同时减少了高满载率区间数量。事件结束后,诱导信息的继续发布可降低突发事件受影响区间7.08%的满载率,并避免乘客在刚恢复正常运营区间上的再次聚集。展开更多
Traffic congestion is one of the main challenges in transportation engineering. It directly impactsthe economy by increasing travel time and affecting the environment by excessive fuel consumptionand emission. Road ro...Traffic congestion is one of the main challenges in transportation engineering. It directly impactsthe economy by increasing travel time and affecting the environment by excessive fuel consumptionand emission. Road route recommendation to overcome the congestion by alternativeroute suggestions has gained high importance. The existing route recommendation systems areproposed using the reinforcement learning algorithm (Q-learning). The techniques suggestedin this paper are state-action-reward-state-action (SARSA) algorithm and dynamic programming(DP) to guide the commuters to reach the destination with an optimal solution. The algorithmconsiders travel time, cost, flexibility, and traffic intensity as the user preference attributes torecommend an optimal route. The recommended system is implemented by building a roadnetwork graph. We assign values to each user preference attribute along the edges, which cantake high(1) or low(0) values. By considering these values, the system recommends the route.The proposed system performance is evaluated based on computation time, cumulative reward,and accuracy. The results show that DP outperforms the SARSA algorithm.展开更多
基金supported in part by the National Key Research and Development Program of China under Grant 2021YFB2900604in part by the National Natural Science Foundation of China(NSFC)under Grant U22B2033,61975234,61875230。
文摘With the development of satellite communication,in order to solve the problems of shortage of on-board resources and refinement of delay requirements to improve the communication performance of satellite optical networks,this paper proposes a bee colony optimization algorithm for routing and wavelength assignment based on directional guidance(DBCO-RWA)in satellite optical networks.In D-BCORWA,directional guidance based on relative position and link load is defined,and then the link cost function in the path search stage is established based on the directional guidance factor.Finally,feasible solutions are expanded in the global optimization stage.The wavelength utilization,communication success probability,blocking rate,communication hops and convergence characteristic are simulated.The results show that the performance of the proposed algorithm is improved compared with existing algorithms.
文摘This paper describes a cooperative decentralized architecture for reactive real-time route guidance. The architecture is cooperative in the sense that it allows adjacent local controllers to exchange information regarding the traffic conditions in their territories. A set of local decision rules and associated heuristic functions to support the cooperative architecture are specified. A protocol governing the knowledge exchange among local adjacent controllers is developed. A simulation-assignment modeling framework is used for assessing the effectiveness of this cooperative architecture under various levels of controller knowledge and network traffic congestion. The cooperative decentralized system is tested under various scenarios of knowledge and cooperation and network traffic demand levels. The cooperative system is compared against the shortest path algorithm as a benchmark.
文摘Haptic(vibration)information expression is an effective human-computer interaction mode and information transfer method.It makes up shortcomings of sound under certain conditions and is an important channel of information transfer for route guidance field.As a special kind of walkers,the visually impaired pedestrians have a specific type of cognition or perception of route guidance environment(including spatial orientation,distance and walking speed etc.)and they have sharp sense of touch resources form the ordinary.This work integrated application of GPS,GIS and Haptic(vibration)technology to develop more reliable mode route guidance for the visually impaired.It provides different vibration to the user under two circumstances:key nodes of roads ahead and deviation planning path.It resists environmental noise,reflects timely and has high effectiveness.Based on Google Legend phone,we developed the prototype and realized the designed functions,and verified the effectiveness of the system.We initially determined the thresholds of deviating from the path,those at road junctions and other nodes through experiments,interviews etc.And we used the thresholds for experiments testing and guiding.Then they were inspected,corrected and improved in the field practice.Finally,more reasonable thresholds were drawn out for future applications in reality.
基金Sponsored by the Ministerial Level Advanced Research Foundation(51401050105BQ01)
文摘In order to increase the aircraft's survival in the flight mission, it is necessary to carry out flight mission planning, which includes TF/TA2( terrain following/terrain avoidance/threat avoidance). An approach to 3D-route planning based on A * heuristic search algorithm was selected to determine the routes of fiber optic guidance missile' s cruise segment. The cost function was discussed, which was mainly related to the physical obstacle, threat exposure, and aircraft performance characteristics. The digital map techniques were presented, which included setting "no-go" area according to fiber's safety requirement. The optimal or the sub-optimal route was obtained, while the cost function constraints were satisfied and the stored terrain obtained from a real terrain was digitized. The algorithm is validated through simulation and can fulfill the route planning task which focuses on the cruise segment of fiber optic guidance missile.
基金Supported by the Provincial Government Decision-making Tender Subject(2013B318)Supported by the Educational Committee of Henan Province of China(15A520004)
文摘Optimal route selection is an important function of vehicle trac flow guidance system. Its core is to determine the index weight for measuring the route merits and to determine the evaluation method for selecting route. In this paper, subjective weighting method which relies on driver preference is used to determine the weight and the paper proposes the multi-criteria weighted decision method based on vague sets for selecting the optimal route. Examples show that, the usage of vague sets to describe route index value can provide more decision-making information for route selection.
基金partially supported by the STI 2030-Major Projects(No.2022ZD0208804)the Postdoctoral Fellows of Beihang“Zhuoyue”Program,China。
文摘Formation control of fixed-wing aerial vehicles is an important yet rarely addressed problem because of their complex dynamics and various motion constraints,such as nonholonomic and velocity constraints.The guidance-route-based strategy has been demonstrated to be applicable to fixed-wing aircraft.However,it requires a global coordinator and there exists control lag,due to its own natures.For this reason,this paper presents a fully distributed guidance-route-based formation approach to address the aforementioned issues.First,a hop-count scheme is introduced to achieve distributed implementation,in which each aircraft chooses a neighbor with the minimum hop-count as a reference to generate its guidance route using only local information.Next,the model predictive control algorithm is employed to eliminate the control lag and achieve precise formation shape control.In addition,the stall protection and collision avoidance are also considered.Finally,three numerical simulations demonstrate that our proposed approach can implement precise formation shape control of fixed-wing aircraft in a fully distributed manner.
文摘Walking,as the main mode of soft mobility,has become an integral aspect of urban tourism.The development of pedestrian tourist routes plays a crucial role in enhancing the positive walking experience in urban tourist destinations.This research employs a hybrid multi-criteria decision-making(MCDM)with GIS to rank street segments,establishing walking-oriented tourist paths in Shiraz’s historic district,Iran.The initial steps involve identifying pivotal criteria through literature reviews and expert surveys.The Analytical Hierarchy Process(AHP)establishes criteria and sub-criteria weights using input from 30 experts.The Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)then prioritizes street segments based on sub-criteria such as traffic safety,image ability and heritage assets,security,land use and activity,accessibility,comfort and convenience,and human scale.Furthermore,a Space Syntax analysis(SSA)is conducted to evaluate the morphology of the street network in the study area and identify streets with potential for pedestrian movement.By integrating these analyses,a prime corridor for a pedestrian tourist route is identified.This study offers planners and policymakers a valuable tool for pre-investment decision-making,aiding the promotion of walkability in tourist-centric areas.
基金co-supported by the National Natural Science Foundation of China(Nos.61773031 and 61573042)Graduate Innovation Practice Fund of Beihang University,China(No.YCSJ-01-201915)funded by the State Key Laboratory of Software Development Environment,China.
文摘In recent years,formation control of multi-agent has been a significant research subject in the field of cooperative control.However,previous works have mainly concentrated on formation control for simple point-mass model and linear model.In contrast,this paper presents a novel cooperative algorithm for multiple air vehicles formation control,which aims to devise a control strategy based on guidance route to achieve precisely coordinated formation control for a group of fixed-wing aircraft in a complex task environment.The proposed method introduces the leader-follower structure for effective organization of the multi-agent coordination.Moreover,the Partial Integrated Formation and Control(PIFC)is adopted to design the control law for Guidance-Route based Formation Control(GRFC).Additionally,the proposed approach designs two guidance-route generation strategies for two special situations to demonstrate the effectiveness of GRFC in complex task environments.Theoretical analysis reveals that the proposed control protocol for guidance command can ensure the overall stability and tracking accuracy of the system.Numerical simulations are performed to illustrate the theoretical results,and verify that the proposed approach can achieve coordinated formation control precisely in a complex task environment.
文摘运营突发事件下,向城市轨道交通(城轨)乘客有针对性地发布诱导信息,是实现高效疏导、确保城轨运营安全的重要举措。本文考虑乘客异质性,开展突发事件下城轨诱导信息发布策略研究。首先,基于潜在分类模型(Latent Class Model,LCM)构建城轨乘客在突发事件和诱导信息双重作用下的路径选择行为模型,分析乘客对诱导信息接受程度及路径选择偏好的差异。其次,以线网乘客总出行时间和线网客流分布均衡性基尼系数为优化目标,构建基于路径选择行为分析的信息诱导优化模型,并应用非支配排序遗传算法(Non-dominated Sorting Genetic AlgorithmⅡ,NSGA-Ⅱ)求解,以获得突发事件下受影响起讫点(Origin and Destination,OD)间各有效路径的最优推荐指数。最后,以北京市工作日早高峰城轨区域线网进行案例分析。结果表明:城轨乘客在突发事件下对诱导信息存在“诱导服从型”“诱导中立型”“诱导无视型”这3类不同接受程度的群体。提供诱导信息后,线网乘客总出行时间减少3.906%,线网客流分布均衡性基尼系数下降4.063%,同时减少了高满载率区间数量。事件结束后,诱导信息的继续发布可降低突发事件受影响区间7.08%的满载率,并避免乘客在刚恢复正常运营区间上的再次聚集。
文摘Traffic congestion is one of the main challenges in transportation engineering. It directly impactsthe economy by increasing travel time and affecting the environment by excessive fuel consumptionand emission. Road route recommendation to overcome the congestion by alternativeroute suggestions has gained high importance. The existing route recommendation systems areproposed using the reinforcement learning algorithm (Q-learning). The techniques suggestedin this paper are state-action-reward-state-action (SARSA) algorithm and dynamic programming(DP) to guide the commuters to reach the destination with an optimal solution. The algorithmconsiders travel time, cost, flexibility, and traffic intensity as the user preference attributes torecommend an optimal route. The recommended system is implemented by building a roadnetwork graph. We assign values to each user preference attribute along the edges, which cantake high(1) or low(0) values. By considering these values, the system recommends the route.The proposed system performance is evaluated based on computation time, cumulative reward,and accuracy. The results show that DP outperforms the SARSA algorithm.