Based on the two-list algorithm and the parallel three-list algorithm, an improved parallel three-list algorithm for knapsack problem is proposed, in which the method of divide and conquer, and parallel merging withou...Based on the two-list algorithm and the parallel three-list algorithm, an improved parallel three-list algorithm for knapsack problem is proposed, in which the method of divide and conquer, and parallel merging without memory conflicts are adopted. To find a solution for the n-element knapsack problem, the proposed algorithm needs O（2^3n/8） time when O（2^3n/8） shared memory units and O（2^n/4） processors are available. The comparisons between the proposed algorithm and 10 existing algorithms show that the improved parallel three-fist algorithm is the first exclusive-read exclusive-write （EREW） parallel algorithm that can solve the knapsack instances in less than O（2^n/2） time when the available hardware resource is smaller than O（2^n/2） , and hence is an improved result over the past researches.展开更多
目的探究社会性不同的拉布拉多犬认知能力是否存在差异。方法参照瑞典工作犬协会(the Swedish Working Dog Association)创建的犬气质评估测试(dog mentality assessment,DMA),使用DMA测试中的社会接触、游戏Ⅰ、距离游戏、扮鬼和游戏Ⅱ...目的探究社会性不同的拉布拉多犬认知能力是否存在差异。方法参照瑞典工作犬协会(the Swedish Working Dog Association)创建的犬气质评估测试(dog mentality assessment,DMA),使用DMA测试中的社会接触、游戏Ⅰ、距离游戏、扮鬼和游戏Ⅱ5个子测试中的12个行为变量来评估犬的社会性,根据评分标准对中国导盲犬大连培训基地提供的49只拉布拉多犬的社会性行为变量进行评分,使用聚类分析将其分为社会性高分组(n=15)和低分组(n=34)。根据Bray等的犬认知发展系列测试(dog cognitive development battery,DCDB)建立了新的犬认知能力测试体系,对犬的社会线索使用、无法解决任务、抑制控制、认知灵活、工作记忆和多步骤解决任务等不同领域的认知能力进行测试,记录犬在测试中的行为表现及持续时长,统计分析社会性不同的犬认知能力是否存在差异。结果社会性高分组与低分组的犬在无法解决任务、抑制控制测试和多步骤解决任务中的行为变量上存在显著差异。在无法解决任务中,社会性高分组的犬注视人时长显著高于社会性低分组的犬(P=0.008),注视人潜伏时长显著低于社会性低分组的犬(P=0.0001)。在抑制控制测试中,社会性高分组的犬选择正确率显著高于社会性低分组的犬(P=0.034),选择时长显著低于社会性低分组的犬(P=0.039)。在多步骤解决任务中,社会性高分组的犬完成木桩任务数量显著高于社会性低分组的犬(P=0.044);操作木桩时长占比显著低于社会性低分组的犬(P=0.05);完成骨头盘任务平均时长显著高于社会性低分组的犬(P=0.037);操作骨头盘时长占比显著低于社会性低分组的犬(P=0.038)。涉及可操作仪器的测试中,社会性高分组的犬注视人时长高于社会性低分组的犬,操作仪器时长低于低分组的犬,但经统计无显著差异(P>0.05)。结论社会性不同的犬的认知能力存在差异。社会性好的拉布拉多犬表现出更强的认知能力,它们在测试时抑制冲动的能力更强,完成多步骤解决任务的能力更强,在遇到无法解决任务时更倾向于转变策略向人寻求新线索而不是执着于操作仪器。展开更多
A conflict is an event in which two or more aircraft experience a loss of minimum separation. In this paper, we formulate the problem of solving conflicts arising among several aircraft moving in a shared airspace as ...A conflict is an event in which two or more aircraft experience a loss of minimum separation. In this paper, we formulate the problem of solving conflicts arising among several aircraft moving in a shared airspace as a Constraint Satisfaction Problem (CSP). The constraint satisfaction problem being NP-complete, the algorithms developed to solve it have been of two types: non-systematic and systematic search methods. In this paper, we have considered a breakout algorithm as an example of non-systematic search methods and a backtracking procedure that maintains Arc Consistency (MAC) as an example of systematic search methods. The performance of these algorithms was compared experimentally and the Breakout algorithm is shown to be clearly superior.展开更多
文摘Based on the two-list algorithm and the parallel three-list algorithm, an improved parallel three-list algorithm for knapsack problem is proposed, in which the method of divide and conquer, and parallel merging without memory conflicts are adopted. To find a solution for the n-element knapsack problem, the proposed algorithm needs O（2^3n/8） time when O（2^3n/8） shared memory units and O（2^n/4） processors are available. The comparisons between the proposed algorithm and 10 existing algorithms show that the improved parallel three-fist algorithm is the first exclusive-read exclusive-write （EREW） parallel algorithm that can solve the knapsack instances in less than O（2^n/2） time when the available hardware resource is smaller than O（2^n/2） , and hence is an improved result over the past researches.
文摘目的探究社会性不同的拉布拉多犬认知能力是否存在差异。方法参照瑞典工作犬协会(the Swedish Working Dog Association)创建的犬气质评估测试(dog mentality assessment,DMA),使用DMA测试中的社会接触、游戏Ⅰ、距离游戏、扮鬼和游戏Ⅱ5个子测试中的12个行为变量来评估犬的社会性,根据评分标准对中国导盲犬大连培训基地提供的49只拉布拉多犬的社会性行为变量进行评分,使用聚类分析将其分为社会性高分组(n=15)和低分组(n=34)。根据Bray等的犬认知发展系列测试(dog cognitive development battery,DCDB)建立了新的犬认知能力测试体系,对犬的社会线索使用、无法解决任务、抑制控制、认知灵活、工作记忆和多步骤解决任务等不同领域的认知能力进行测试,记录犬在测试中的行为表现及持续时长,统计分析社会性不同的犬认知能力是否存在差异。结果社会性高分组与低分组的犬在无法解决任务、抑制控制测试和多步骤解决任务中的行为变量上存在显著差异。在无法解决任务中,社会性高分组的犬注视人时长显著高于社会性低分组的犬(P=0.008),注视人潜伏时长显著低于社会性低分组的犬(P=0.0001)。在抑制控制测试中,社会性高分组的犬选择正确率显著高于社会性低分组的犬(P=0.034),选择时长显著低于社会性低分组的犬(P=0.039)。在多步骤解决任务中,社会性高分组的犬完成木桩任务数量显著高于社会性低分组的犬(P=0.044);操作木桩时长占比显著低于社会性低分组的犬(P=0.05);完成骨头盘任务平均时长显著高于社会性低分组的犬(P=0.037);操作骨头盘时长占比显著低于社会性低分组的犬(P=0.038)。涉及可操作仪器的测试中,社会性高分组的犬注视人时长高于社会性低分组的犬,操作仪器时长低于低分组的犬,但经统计无显著差异(P>0.05)。结论社会性不同的犬的认知能力存在差异。社会性好的拉布拉多犬表现出更强的认知能力,它们在测试时抑制冲动的能力更强,完成多步骤解决任务的能力更强,在遇到无法解决任务时更倾向于转变策略向人寻求新线索而不是执着于操作仪器。
文摘A conflict is an event in which two or more aircraft experience a loss of minimum separation. In this paper, we formulate the problem of solving conflicts arising among several aircraft moving in a shared airspace as a Constraint Satisfaction Problem (CSP). The constraint satisfaction problem being NP-complete, the algorithms developed to solve it have been of two types: non-systematic and systematic search methods. In this paper, we have considered a breakout algorithm as an example of non-systematic search methods and a backtracking procedure that maintains Arc Consistency (MAC) as an example of systematic search methods. The performance of these algorithms was compared experimentally and the Breakout algorithm is shown to be clearly superior.
