A task allocation problem for the heterogeneous unmanned aerial vehicle (UAV) swarm in unknown environments is studied in this paper.Considering that the actual mission environment information may be unknown,the UAV s...A task allocation problem for the heterogeneous unmanned aerial vehicle (UAV) swarm in unknown environments is studied in this paper.Considering that the actual mission environment information may be unknown,the UAV swarm needs to detect the environment first and then attack the detected targets.The heterogeneity of UAVs,multiple types of tasks,and the dynamic nature of task environment lead to uneven load and time sequence problems.This paper proposes an improved contract net protocol (CNP) based task allocation scheme,which effectively balances the load of UAVs and improves the task efficiency.Firstly,two types of task models are established,including regional reconnaissance tasks and target attack tasks.Secondly,for regional reconnaissance tasks,an improved CNP algorithm using the uncertain contract is developed.Through uncertain contracts,the area size of the regional reconnaissance task is determined adaptively after this task assignment,which can improve reconnaissance efficiency and resource utilization.Thirdly,for target attack tasks,an improved CNP algorithm using the fuzzy integrated evaluation and the double-layer negotiation is presented to enhance collaborative attack efficiency through adjusting the assignment sequence adaptively and multi-layer allocation.Finally,the effectiveness and advantages of the improved method are verified through comparison simulations.展开更多
设置模拟氮沉降的控制试验,以NH4NO3作为外加氮源,设计CK(0 kg N hm-2·a-1)、LN(50 kg N hm-2·a-1)、MN(100 kgN hm-2·a-1)、HN(150 kg N hm-2·a-1)4个处理,历时9个月,测定木荷(Schima superba)幼苗的光合特性、生...设置模拟氮沉降的控制试验,以NH4NO3作为外加氮源,设计CK(0 kg N hm-2·a-1)、LN(50 kg N hm-2·a-1)、MN(100 kgN hm-2·a-1)、HN(150 kg N hm-2·a-1)4个处理,历时9个月,测定木荷(Schima superba)幼苗的光合特性、生物量和C、N、P含量及其分配格局对氮沉降的响应。结果表明:(1)木荷幼苗的最大净光合速率和光饱和点随着氮处理水平增加呈先增加后减小的特点,在中氮处理下极显著增加(P<0.01)。氮处理降低了幼苗的光补偿点和暗呼吸速率,光补偿点在低氮处理下显著降低(P<0.05),暗呼吸速率在低中氮处理下极显著降低(P<0.01),高氮处理下显著降低(P<0.05)。未见氮处理对表观量子效率产生显著影响。(2)氮处理促进了木荷的全株生物量以及各部分生物量的增长。随着氮处理水平的增加,叶重比呈升高的趋势,而根重比和根冠比呈降低的趋势,在高氮处理下叶重比的增加和根重比、根冠比的降低都达到了显著水平(P<0.05)。(3)氮沉降促进各器官N含量的增加,在高氮处理下根和茎中N含量极显著增加(P<0.01),叶中N含量显著增加(P<0.05)。而各器官C含量随着氮沉降程度的增加呈先增加后降低的趋势,在中氮处理下根和茎中C含量极显著增加(P<0.01),叶中C含量显著增加(P<0.05)。但各器官P含量变化趋势各不相同,随着氮的增加,根中P含量是呈先增加后降低的趋势,而茎和叶中P含量是呈降低的趋势。氮沉降一定程度上降低了木荷各器官的C/N比值而增加了N/P比值。展开更多
基金National Natural Science Foundation of China (12202293)Sichuan Science and Technology Program (2023NSFSC0393,2022NSFSC1952)。
文摘A task allocation problem for the heterogeneous unmanned aerial vehicle (UAV) swarm in unknown environments is studied in this paper.Considering that the actual mission environment information may be unknown,the UAV swarm needs to detect the environment first and then attack the detected targets.The heterogeneity of UAVs,multiple types of tasks,and the dynamic nature of task environment lead to uneven load and time sequence problems.This paper proposes an improved contract net protocol (CNP) based task allocation scheme,which effectively balances the load of UAVs and improves the task efficiency.Firstly,two types of task models are established,including regional reconnaissance tasks and target attack tasks.Secondly,for regional reconnaissance tasks,an improved CNP algorithm using the uncertain contract is developed.Through uncertain contracts,the area size of the regional reconnaissance task is determined adaptively after this task assignment,which can improve reconnaissance efficiency and resource utilization.Thirdly,for target attack tasks,an improved CNP algorithm using the fuzzy integrated evaluation and the double-layer negotiation is presented to enhance collaborative attack efficiency through adjusting the assignment sequence adaptively and multi-layer allocation.Finally,the effectiveness and advantages of the improved method are verified through comparison simulations.
文摘设置模拟氮沉降的控制试验,以NH4NO3作为外加氮源,设计CK(0 kg N hm-2·a-1)、LN(50 kg N hm-2·a-1)、MN(100 kgN hm-2·a-1)、HN(150 kg N hm-2·a-1)4个处理,历时9个月,测定木荷(Schima superba)幼苗的光合特性、生物量和C、N、P含量及其分配格局对氮沉降的响应。结果表明:(1)木荷幼苗的最大净光合速率和光饱和点随着氮处理水平增加呈先增加后减小的特点,在中氮处理下极显著增加(P<0.01)。氮处理降低了幼苗的光补偿点和暗呼吸速率,光补偿点在低氮处理下显著降低(P<0.05),暗呼吸速率在低中氮处理下极显著降低(P<0.01),高氮处理下显著降低(P<0.05)。未见氮处理对表观量子效率产生显著影响。(2)氮处理促进了木荷的全株生物量以及各部分生物量的增长。随着氮处理水平的增加,叶重比呈升高的趋势,而根重比和根冠比呈降低的趋势,在高氮处理下叶重比的增加和根重比、根冠比的降低都达到了显著水平(P<0.05)。(3)氮沉降促进各器官N含量的增加,在高氮处理下根和茎中N含量极显著增加(P<0.01),叶中N含量显著增加(P<0.05)。而各器官C含量随着氮沉降程度的增加呈先增加后降低的趋势,在中氮处理下根和茎中C含量极显著增加(P<0.01),叶中C含量显著增加(P<0.05)。但各器官P含量变化趋势各不相同,随着氮的增加,根中P含量是呈先增加后降低的趋势,而茎和叶中P含量是呈降低的趋势。氮沉降一定程度上降低了木荷各器官的C/N比值而增加了N/P比值。
