Autonomous-rail rapid transit(ART)is a new medium-capacity rapid transportation system with punctuality,comfort and convenience,but low-cost construction.Combined velocity planning is a critical approach to meet the r...Autonomous-rail rapid transit(ART)is a new medium-capacity rapid transportation system with punctuality,comfort and convenience,but low-cost construction.Combined velocity planning is a critical approach to meet the requirements of energy-saving and punctuality.An ART velocity pre-planning and re-planning strategy based on the combination of punctuality dynamic programming(PDP)and pseudospectral(PS)method is proposed in this paper.Firstly,the longitudinal dynamics model of ART is established by a multi-particle model.Secondly,the PDP algorithm with global optimal characteristics is adopted as the pre-planning strategy.A model for determining the number of collocation points of the real-time PS method is proposed to improve the energy-saving effect while ensuring computation efficiency.Then the enhanced PS method is utilized to design the velocity re-planning strategy.Finally,simulations are conducted in the typical scenario with sloping roads,traffic lights,and intrusion of the pedestrian.The simulation results indicate that the ART with the proposed velocity trajectory optimization strategy can meet the punctuality requirement,and obtain better economy efficiency compared with the punctuality green light optimal speed advisory(PGLOSA).展开更多
Path planning is a prevalent process that helps mobile robots find the most efficient pathway from the starting position to the goal position to avoid collisions with obstacles.In this paper,we propose a novel path pl...Path planning is a prevalent process that helps mobile robots find the most efficient pathway from the starting position to the goal position to avoid collisions with obstacles.In this paper,we propose a novel path planning algorithm-Intermediary RRT*-PSO-by utilizing the exploring speed advantages of Rapidly exploring Random Trees and using its solution to feed to a metaheuristic-based optimizer,Particle swarm optimization(PSO),for fine-tuning and enhancement.In Phase 1,the start and goal trees are initialized at the starting and goal positions,respectively,and the intermediary tree is initialized at a random unexplored region of the search space.The trees were grown until one met the other and then merged and re-initialized in other unexplored regions.If the start and goal trees merge,the first solution is found and passed through a minimization process to reduce unnecessary nodes.Phase 2 begins by feeding the minimized solution from Phase 1 as the global best particle of PSO to optimize the path.After simulating two special benchmark configurations and six practice configurations with special cases,the results of the study concluded that the proposed method is capable of handling small to large,simple to complex continuous environments,whereas it was very tedious for the previous method to achieve.展开更多
Public forest recreation area planning is often confronted by conflicting stakeholder views of what actions are most appropriate for improving outdoor recreation areas. Contemporary users of an outdoor recreation area...Public forest recreation area planning is often confronted by conflicting stakeholder views of what actions are most appropriate for improving outdoor recreation areas. Contemporary users of an outdoor recreation area are often inadequately represented in these planning decisions, due to the high cost and time required for user surveys that have traditionally been used to represent these stakeholders. A case example of the application of an alternative research method termed rapid appraisal (RA) is described. Data collected using rapid appraisal was used to help resolve disagreements on future planning and development options for the Little Molas Recreation Area (LMRA). The entire RA process was completed in one month’s time, with results which provided a reliable stakeholder supplement to working group recommendations to the Forest Service for their proposed LMRA redevelopment plan.展开更多
Given that it is difficult to assess the harmfulness and make emergency response timely in the early stage when flood disasters happen in cities for that the data are complex and rapidly changing, this article constru...Given that it is difficult to assess the harmfulness and make emergency response timely in the early stage when flood disasters happen in cities for that the data are complex and rapidly changing, this article constructs a rapid assessment model, namely Simple Simos Procedure and PROMTHEE II Model (SSPPM), to assess the severity of flood disaster occurring in cities at the early stage based on a view of the rapid flood disaster assessment. On this basis, the fuzzy VIKOR method is applied to choose a scientific emergency plan. This article aims to construct a research framework model, which can provide some practice implications to reduce the losses caused by flood disaster.展开更多
The problem of privacy in social networks is well documented within literature;users have pri- vacy concerns however, they consistently disclose their sensitive information and leave it open to unintended third partie...The problem of privacy in social networks is well documented within literature;users have pri- vacy concerns however, they consistently disclose their sensitive information and leave it open to unintended third parties. While numerous causes of poor behaviour have been suggested by re- search the role of the User Interface (UI) and the system itself is underexplored. The field of Per- suasive Technology would suggest that Social Network Systems persuade users to deviate from their normal or habitual behaviour. This paper makes the case that the UI can be used as the basis for user empowerment by informing them of their privacy at the point of interaction and remind- ing them of their privacy needs. The Theory of Planned Behaviour is introduced as a potential theoretical foundation for exploring the psychology behind privacy behaviour as it describes the salient factors that influence intention and action. Based on these factors of personal attitude, subjective norms and perceived control, a series of UIs are presented and implemented in con- trolled experiments examining their effect on personal information disclosure. This is combined with observations and interviews with the participants. Results from this initial, pilot experiment suggest groups with privacy salient information embedded exhibit less disclosure than the control group. This work reviews this approach as a method for exploring privacy behaviour and propos- es further work required.展开更多
Karst groundwater is highly vulnerable to contamination,which urges better land use zoning.This paper proposes a new approach,called COCKPIT-PLUS,to minimize groundwater contamination within cockpit karst regions.The ...Karst groundwater is highly vulnerable to contamination,which urges better land use zoning.This paper proposes a new approach,called COCKPIT-PLUS,to minimize groundwater contamination within cockpit karst regions.The method employed four parameters:P(the existence of ponor/swallow hole),L(lineament density),U(sinking stream to an underground river),and S(distance to spring/pumping site).These parameters are essential for identifying contaminant pathways and transport from the surface to the karst groundwater/springs.COCKPIT-PLUS has been developed and validated in the Gunungsewu karst in Java,Indonesia.This research considers a cockpit as a single hydrological unit that uniquely recharges karst groundwater.We analyzed 2,811 cockpits and 81 other closed depressions to develop a land use planning map.The research used the time to first arrival(Ta),time to peak(Tp),and Q_(max/min)ratio parameters of two karst springs and two underground pumping sites for validation.Cockpits with ponors/swallow holes,sinking streams,high lineament density,and short distances to springs are vulnerable to groundwater and thus must be restricted areas for any land uses.The findings show that though the COCKPIT-PLUS uses a limited karst dataset,the proposed method seems reliable enough for a rapid land-use zoning approach in cockpit karst areas.展开更多
针对快速搜索随机树(RRT)算法在航迹规划过程中存在采样点扩展随机性强、航迹曲折不平滑等问题,提出了一种基于约束随机采样点的RRT(Constrained Random Sampling-based RRT,CRS-RRT)算法。该算法引入人工势场法中的引力场势能函数约束...针对快速搜索随机树(RRT)算法在航迹规划过程中存在采样点扩展随机性强、航迹曲折不平滑等问题,提出了一种基于约束随机采样点的RRT(Constrained Random Sampling-based RRT,CRS-RRT)算法。该算法引入人工势场法中的引力场势能函数约束随机采样点在目标点附近采样,引导随机树朝着目标点生长,提高算法的规划速度,并结合去除冗余节点策略和Minimum Snap航迹平滑方法,在复杂三维环境中可快速生成一条安全、平滑且满足无人机动力学约束的航迹。仿真结果表明,该算法有效提高航迹规划速度并缩短航迹长度。展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.52072073 and 52025121)National Key R&D Program of China(Grant No.2018YFB1201602).
文摘Autonomous-rail rapid transit(ART)is a new medium-capacity rapid transportation system with punctuality,comfort and convenience,but low-cost construction.Combined velocity planning is a critical approach to meet the requirements of energy-saving and punctuality.An ART velocity pre-planning and re-planning strategy based on the combination of punctuality dynamic programming(PDP)and pseudospectral(PS)method is proposed in this paper.Firstly,the longitudinal dynamics model of ART is established by a multi-particle model.Secondly,the PDP algorithm with global optimal characteristics is adopted as the pre-planning strategy.A model for determining the number of collocation points of the real-time PS method is proposed to improve the energy-saving effect while ensuring computation efficiency.Then the enhanced PS method is utilized to design the velocity re-planning strategy.Finally,simulations are conducted in the typical scenario with sloping roads,traffic lights,and intrusion of the pedestrian.The simulation results indicate that the ART with the proposed velocity trajectory optimization strategy can meet the punctuality requirement,and obtain better economy efficiency compared with the punctuality green light optimal speed advisory(PGLOSA).
基金funded by International University,VNU-HCM under Grant Number T2021-02-IEM.
文摘Path planning is a prevalent process that helps mobile robots find the most efficient pathway from the starting position to the goal position to avoid collisions with obstacles.In this paper,we propose a novel path planning algorithm-Intermediary RRT*-PSO-by utilizing the exploring speed advantages of Rapidly exploring Random Trees and using its solution to feed to a metaheuristic-based optimizer,Particle swarm optimization(PSO),for fine-tuning and enhancement.In Phase 1,the start and goal trees are initialized at the starting and goal positions,respectively,and the intermediary tree is initialized at a random unexplored region of the search space.The trees were grown until one met the other and then merged and re-initialized in other unexplored regions.If the start and goal trees merge,the first solution is found and passed through a minimization process to reduce unnecessary nodes.Phase 2 begins by feeding the minimized solution from Phase 1 as the global best particle of PSO to optimize the path.After simulating two special benchmark configurations and six practice configurations with special cases,the results of the study concluded that the proposed method is capable of handling small to large,simple to complex continuous environments,whereas it was very tedious for the previous method to achieve.
文摘Public forest recreation area planning is often confronted by conflicting stakeholder views of what actions are most appropriate for improving outdoor recreation areas. Contemporary users of an outdoor recreation area are often inadequately represented in these planning decisions, due to the high cost and time required for user surveys that have traditionally been used to represent these stakeholders. A case example of the application of an alternative research method termed rapid appraisal (RA) is described. Data collected using rapid appraisal was used to help resolve disagreements on future planning and development options for the Little Molas Recreation Area (LMRA). The entire RA process was completed in one month’s time, with results which provided a reliable stakeholder supplement to working group recommendations to the Forest Service for their proposed LMRA redevelopment plan.
基金Acknowledgments The authors gratefully acknowledge the financial support provided by Foundation for Distinguished Young Talents in Higher Education of Guangdong, China （Project No： wyrnl1049） and the Natural Natural Science Foundation of China （Project No. 40901066）.
文摘Given that it is difficult to assess the harmfulness and make emergency response timely in the early stage when flood disasters happen in cities for that the data are complex and rapidly changing, this article constructs a rapid assessment model, namely Simple Simos Procedure and PROMTHEE II Model (SSPPM), to assess the severity of flood disaster occurring in cities at the early stage based on a view of the rapid flood disaster assessment. On this basis, the fuzzy VIKOR method is applied to choose a scientific emergency plan. This article aims to construct a research framework model, which can provide some practice implications to reduce the losses caused by flood disaster.
文摘The problem of privacy in social networks is well documented within literature;users have pri- vacy concerns however, they consistently disclose their sensitive information and leave it open to unintended third parties. While numerous causes of poor behaviour have been suggested by re- search the role of the User Interface (UI) and the system itself is underexplored. The field of Per- suasive Technology would suggest that Social Network Systems persuade users to deviate from their normal or habitual behaviour. This paper makes the case that the UI can be used as the basis for user empowerment by informing them of their privacy at the point of interaction and remind- ing them of their privacy needs. The Theory of Planned Behaviour is introduced as a potential theoretical foundation for exploring the psychology behind privacy behaviour as it describes the salient factors that influence intention and action. Based on these factors of personal attitude, subjective norms and perceived control, a series of UIs are presented and implemented in con- trolled experiments examining their effect on personal information disclosure. This is combined with observations and interviews with the participants. Results from this initial, pilot experiment suggest groups with privacy salient information embedded exhibit less disclosure than the control group. This work reviews this approach as a method for exploring privacy behaviour and propos- es further work required.
文摘Karst groundwater is highly vulnerable to contamination,which urges better land use zoning.This paper proposes a new approach,called COCKPIT-PLUS,to minimize groundwater contamination within cockpit karst regions.The method employed four parameters:P(the existence of ponor/swallow hole),L(lineament density),U(sinking stream to an underground river),and S(distance to spring/pumping site).These parameters are essential for identifying contaminant pathways and transport from the surface to the karst groundwater/springs.COCKPIT-PLUS has been developed and validated in the Gunungsewu karst in Java,Indonesia.This research considers a cockpit as a single hydrological unit that uniquely recharges karst groundwater.We analyzed 2,811 cockpits and 81 other closed depressions to develop a land use planning map.The research used the time to first arrival(Ta),time to peak(Tp),and Q_(max/min)ratio parameters of two karst springs and two underground pumping sites for validation.Cockpits with ponors/swallow holes,sinking streams,high lineament density,and short distances to springs are vulnerable to groundwater and thus must be restricted areas for any land uses.The findings show that though the COCKPIT-PLUS uses a limited karst dataset,the proposed method seems reliable enough for a rapid land-use zoning approach in cockpit karst areas.
文摘针对快速搜索随机树(RRT)算法在航迹规划过程中存在采样点扩展随机性强、航迹曲折不平滑等问题,提出了一种基于约束随机采样点的RRT(Constrained Random Sampling-based RRT,CRS-RRT)算法。该算法引入人工势场法中的引力场势能函数约束随机采样点在目标点附近采样,引导随机树朝着目标点生长,提高算法的规划速度,并结合去除冗余节点策略和Minimum Snap航迹平滑方法,在复杂三维环境中可快速生成一条安全、平滑且满足无人机动力学约束的航迹。仿真结果表明,该算法有效提高航迹规划速度并缩短航迹长度。
