柔性制造系统(flexible manufacturing system,FMS)调度问题属于NP难题,针对该问题利用赋时库所Petri网(timed place Petri net,TPPN)对FMS进行建模,在此基础上,提出了利用改进的嵌套分区(nested partitions,NP)算法对建立的TPPN模型进...柔性制造系统(flexible manufacturing system,FMS)调度问题属于NP难题,针对该问题利用赋时库所Petri网(timed place Petri net,TPPN)对FMS进行建模,在此基础上,提出了利用改进的嵌套分区(nested partitions,NP)算法对建立的TPPN模型进行优化调度.采用来自半导体制造的末端测试系统数据做数值试验,结果表明,基于TPPN模型的改进嵌套分区优化调度算法较其它常用算法具有更好的平衡指数,可有效降低最大完工时间.展开更多
The specific spatial distribution and habitat association--strongly influenced by environmental fac- tors or competitive interactions--are major issues in ecology and conservation. We located and georeferenced nesting...The specific spatial distribution and habitat association--strongly influenced by environmental fac- tors or competitive interactions--are major issues in ecology and conservation. We located and georeferenced nesting sites of five cliff-nesting raptors （Egyptian vulture Neophron percnopterus [a locally extinct species], common buzzard Buteo buteo, osprey Pandion haliaetus, common kes- trel Falco tinnunculus, Barbary falcon Falco peregrinus pelegrinoides）, and common raven Corvus corax on one of the most biodiverse hotspot within the Canary Islands （Teno, Tenerife）. We used generalized linear models to evaluate the factors affecting abundance, richness, and intra- and interspecific interactions. Raptor abundance increased with slope, shrub-covered area, and habitat diversity, and decreased with altitude, and forested and grassed areas. Richness increased with slope and decreased with altitude. Threatened species （osprey, Barbary falcon, and raven） occu- pied cliffs farther away from houses and roads, and more rugged areas than the non-threatened species. The models suggested that the probability of cliff occupation by buzzards, falcons, and rav- ens depended only on inter-specific interactions. Buzzard occupation increased with the distance to the nearest raven and kestrel nests, whereas falcons and ravens seek proximity to each other. Teno holds between 75% and 100% of the insular breeding populations of the most endangered species （osprey and raven）, indicating the high conservation value of this area. Our study suggests that the preservation of rugged terrains and areas of low human pressure are key factors for raptor conservation and provide basic knowledge on the community structure and habitat associations to develop appropriated management actions for these fragile island populations.展开更多
文摘柔性制造系统(flexible manufacturing system,FMS)调度问题属于NP难题,针对该问题利用赋时库所Petri网(timed place Petri net,TPPN)对FMS进行建模,在此基础上,提出了利用改进的嵌套分区(nested partitions,NP)算法对建立的TPPN模型进行优化调度.采用来自半导体制造的末端测试系统数据做数值试验,结果表明,基于TPPN模型的改进嵌套分区优化调度算法较其它常用算法具有更好的平衡指数,可有效降低最大完工时间.
文摘The specific spatial distribution and habitat association--strongly influenced by environmental fac- tors or competitive interactions--are major issues in ecology and conservation. We located and georeferenced nesting sites of five cliff-nesting raptors （Egyptian vulture Neophron percnopterus [a locally extinct species], common buzzard Buteo buteo, osprey Pandion haliaetus, common kes- trel Falco tinnunculus, Barbary falcon Falco peregrinus pelegrinoides）, and common raven Corvus corax on one of the most biodiverse hotspot within the Canary Islands （Teno, Tenerife）. We used generalized linear models to evaluate the factors affecting abundance, richness, and intra- and interspecific interactions. Raptor abundance increased with slope, shrub-covered area, and habitat diversity, and decreased with altitude, and forested and grassed areas. Richness increased with slope and decreased with altitude. Threatened species （osprey, Barbary falcon, and raven） occu- pied cliffs farther away from houses and roads, and more rugged areas than the non-threatened species. The models suggested that the probability of cliff occupation by buzzards, falcons, and rav- ens depended only on inter-specific interactions. Buzzard occupation increased with the distance to the nearest raven and kestrel nests, whereas falcons and ravens seek proximity to each other. Teno holds between 75% and 100% of the insular breeding populations of the most endangered species （osprey and raven）, indicating the high conservation value of this area. Our study suggests that the preservation of rugged terrains and areas of low human pressure are key factors for raptor conservation and provide basic knowledge on the community structure and habitat associations to develop appropriated management actions for these fragile island populations.
