To conduct marine surveys,multiple unmanned surface vessels(Multi-USV)with different capabilities perform collaborative mapping in multiple designated areas.This paper proposes a task allocation algorithm based on int...To conduct marine surveys,multiple unmanned surface vessels(Multi-USV)with different capabilities perform collaborative mapping in multiple designated areas.This paper proposes a task allocation algorithm based on integer linear programming(ILP)with flow balance constraints,ensuring the fair and efficient distribution of sub-areas among USVs and maintaining strong connectivity of assigned regions.In the established gridmap,a search-based path planning algorithm is performed on the sub-areas according to the allocation scheme.It uses the greedy algorithm and the A*algorithm to achieve complete coverage of the barrier-free area and obtain an efficient trajectory of each USV.The greedy algorithm enables fast local traversal of unvisited grids,while the A*algorithm ensures navigation to escape from deadlock areas and maintains global path continuity.The comparison of task allocation results proves that the task allocation algorithm based on ILP improves the mapping efficiency and task distribution fairness.The proposed allocation method and result analysis provide a certain reference for the practical application ofMulti-USV to perform survey tasks collaboratively.展开更多
A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they...A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they belong to the;32 Ma Comei LIP（Zhu et al.,2009）or展开更多
A novel thermogravimetric analyzer system of furnace with multiple temperature controller was described,which mainly decreased the analysis cycle duration down to 20 min.Furthermore,the present C591 rapid analyzer sys...A novel thermogravimetric analyzer system of furnace with multiple temperature controller was described,which mainly decreased the analysis cycle duration down to 20 min.Furthermore,the present C591 rapid analyzer system under software can monitor and control some coal physical and chemical properties like change of coal,control com- bustion regulation,operation of coal mixture,and improvement of the turnover rate of the transportation facilities as well.展开更多
Medium access control( MAC) protocol of underwater acoustic communication network is a key technology for underwater acoustic networks( UANs). Most of the MAC protocols for wireless terrestrial communication networks ...Medium access control( MAC) protocol of underwater acoustic communication network is a key technology for underwater acoustic networks( UANs). Most of the MAC protocols for wireless terrestrial communication networks have been designed with negligible propagation delay. If it is deployed directly in an underwater environment,the UANs will perform inefficiently. In this paper,the characteristics of underwater acoustic channel are modeled and simulated by using the OPNET simulation tool,which are the speed of sound, propagation loss, and four sources for ambient noise: the turbulence,shipping,wind driven waves and thermal noise. The performance of pure Aloha( P-Aloha),carrier sense multiple access with collision avoidance( CSMA / CA) and multiple access collision avoidance for wireless local area network( MACAW) protocols in underwater acoustic channel environment are evaluated. The different performance of protocols in underwater environment is compared in the simulation.展开更多
基金supported in part by the International Science and Technology Project of Guangzhou Development District under Grant 2023GH08the Science and Technology Development Fund,MSAR,under Grants 0029/2022/AGJ and 0029/2023/RIA1the Program of Guangdong under Grant 2023A0505020003.
文摘To conduct marine surveys,multiple unmanned surface vessels(Multi-USV)with different capabilities perform collaborative mapping in multiple designated areas.This paper proposes a task allocation algorithm based on integer linear programming(ILP)with flow balance constraints,ensuring the fair and efficient distribution of sub-areas among USVs and maintaining strong connectivity of assigned regions.In the established gridmap,a search-based path planning algorithm is performed on the sub-areas according to the allocation scheme.It uses the greedy algorithm and the A*algorithm to achieve complete coverage of the barrier-free area and obtain an efficient trajectory of each USV.The greedy algorithm enables fast local traversal of unvisited grids,while the A*algorithm ensures navigation to escape from deadlock areas and maintains global path continuity.The comparison of task allocation results proves that the task allocation algorithm based on ILP improves the mapping efficiency and task distribution fairness.The proposed allocation method and result analysis provide a certain reference for the practical application ofMulti-USV to perform survey tasks collaboratively.
基金supported by National Science Foundation of China (Grant No. 41425010 & 41503023)China Geological Survey (Grant No. 12120114022701 & 12120115027101)
文摘A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they belong to the;32 Ma Comei LIP（Zhu et al.,2009）or
文摘A novel thermogravimetric analyzer system of furnace with multiple temperature controller was described,which mainly decreased the analysis cycle duration down to 20 min.Furthermore,the present C591 rapid analyzer system under software can monitor and control some coal physical and chemical properties like change of coal,control com- bustion regulation,operation of coal mixture,and improvement of the turnover rate of the transportation facilities as well.
基金National Natural Science Foundations of China(Nos.60872073,6097501,and 51075068)the Doctoral Fund of Ministry of Education of China(No.20110092130004)the Research Foundation and Education Bureau of Anhui Province of China(No.KJ2009B137)
文摘Medium access control( MAC) protocol of underwater acoustic communication network is a key technology for underwater acoustic networks( UANs). Most of the MAC protocols for wireless terrestrial communication networks have been designed with negligible propagation delay. If it is deployed directly in an underwater environment,the UANs will perform inefficiently. In this paper,the characteristics of underwater acoustic channel are modeled and simulated by using the OPNET simulation tool,which are the speed of sound, propagation loss, and four sources for ambient noise: the turbulence,shipping,wind driven waves and thermal noise. The performance of pure Aloha( P-Aloha),carrier sense multiple access with collision avoidance( CSMA / CA) and multiple access collision avoidance for wireless local area network( MACAW) protocols in underwater acoustic channel environment are evaluated. The different performance of protocols in underwater environment is compared in the simulation.
