A new method for sector optimum partition of airspace is proposed by dividing the fright altitude into several layers according to the distribution characteristics of the controller＇s workloads in an airspace. On the...A new method for sector optimum partition of airspace is proposed by dividing the fright altitude into several layers according to the distribution characteristics of the controller＇s workloads in an airspace. On the basis of the original distribution of the waypoints at each level of altitude, the sweel5 line algorithm of Voronoi diagram is used to divide them into certain polygons （ elements）, and the controller＇s workloads are calculated in each Voronoi polygon. Then by the rule about balance of controller＇s workload and by adding conditions of control handover or coordination for the sector, a mathematical model for the controller＇s workload based sector optimization is built. By the model, the Voronoi polygons are optimally partitioned. As a result, a 3D sector optimum partition of the whole airspace is formed by combining the sector optimum partitions at every layer. The actual airspace partition for Xiamen Airport has proved the reasonability and effectiveness of the 3D sector optimum partition of airspace proposed.展开更多
Parental food provisioning is crucial for the growth and survival of offspring.Growth rate depends on food quality and food supplied to offspring may differ from what adults use for their own.In the case of steppe pas...Parental food provisioning is crucial for the growth and survival of offspring.Growth rate depends on food quality and food supplied to offspring may differ from what adults use for their own.In the case of steppe passerine birds,detailed characterization on nestling dietary composition,as well as prey choice and resource partitioning among species,is a pending subject.Dietary differences between nestlings and adults remain also largely unexplored.By using faecal DNA metabarcoding,we described the diet of nestlings and adults of five shrub-steppe passerine species over the 2017–2019 breeding seasons in central Spain.We also monitored arthropod availability in the field to assess dietary selection.We expected interspecific dietary differences to limit competition for food resources among sympatric species,as well as parental selection of high quality prey for nestlings.We also predicted age-related differences,with nestlings being fed nutrient-rich prey more frequently than adults.The main arthropod orders provisioned to nestlings were Orthoptera,Julida,Araneae and Lepidoptera.Nestlings of the different species showed high interspecific diet overlap,indicating both a coincidence in growth needs among bird species and no or little limitation of the most profitable resources during the breeding season.Adults of all species showed higher diet richness than nestlings,and age-related differences in prey composition were mainly driven by the selection of the most easily digestible,larger protein-and calcium-rich prey for nestlings,which may favour their rapid growth,and avoiding highly sclerotized and less nutritional prey such as ants.Our study sheds light on the basic ecology and conservation of these declining steppe birds,indicating that interspecific competition may not be a major factor during the breeding season.Given the current global decline of arthropods,further long-term research would be necessary,along with the implementation of effective conservation measures that ensure a sufficient availability of resources identified as key prey in the diet of steppe bird nestlings.展开更多
Multivariate spline function is an important research object and tool in Computational Geometry. The singularity of multivariate spline spaces is a difficult problem that is ineritable in the research of the structure...Multivariate spline function is an important research object and tool in Computational Geometry. The singularity of multivariate spline spaces is a difficult problem that is ineritable in the research of the structure of multivariate spline spaces. The aim of this paper is to reveal the geometric significance of the singularity of bivariate spline space over Morgan-Scott type triangulation by using some new concepts proposed by the first author such as characteristic ratio, characteristic mapping of lines （or ponits）, and characteristic number of algebraic curve. With these concepts and the relevant results, a polished necessary and sufficient conditions for the singularity of spline space S u＋1^u （△MS^u） are geometrically given for any smoothness u by recursion. Moreover, the famous Pascal＇s theorem is generalized to algebraic plane curves of degree n≥3.展开更多
基金The National Natural Science Foundation of China (No.60472117)
文摘A new method for sector optimum partition of airspace is proposed by dividing the fright altitude into several layers according to the distribution characteristics of the controller＇s workloads in an airspace. On the basis of the original distribution of the waypoints at each level of altitude, the sweel5 line algorithm of Voronoi diagram is used to divide them into certain polygons （ elements）, and the controller＇s workloads are calculated in each Voronoi polygon. Then by the rule about balance of controller＇s workload and by adding conditions of control handover or coordination for the sector, a mathematical model for the controller＇s workload based sector optimization is built. By the model, the Voronoi polygons are optimally partitioned. As a result, a 3D sector optimum partition of the whole airspace is formed by combining the sector optimum partitions at every layer. The actual airspace partition for Xiamen Airport has proved the reasonability and effectiveness of the 3D sector optimum partition of airspace proposed.
基金supported by the European Commission LIFE Ricotí(LIFE15-NAT-ES-000802)LIFE Connect Ricotí(LIFE20-NAT-ES000133)projects+1 种基金This is a contribution to the Excellence Network Remedinal TE-CM(S2013/MAE2719)JG-C is funded by a Margarita Salas postdoctoral fellowship(CA4/RSUE/2022-00205)。
文摘Parental food provisioning is crucial for the growth and survival of offspring.Growth rate depends on food quality and food supplied to offspring may differ from what adults use for their own.In the case of steppe passerine birds,detailed characterization on nestling dietary composition,as well as prey choice and resource partitioning among species,is a pending subject.Dietary differences between nestlings and adults remain also largely unexplored.By using faecal DNA metabarcoding,we described the diet of nestlings and adults of five shrub-steppe passerine species over the 2017–2019 breeding seasons in central Spain.We also monitored arthropod availability in the field to assess dietary selection.We expected interspecific dietary differences to limit competition for food resources among sympatric species,as well as parental selection of high quality prey for nestlings.We also predicted age-related differences,with nestlings being fed nutrient-rich prey more frequently than adults.The main arthropod orders provisioned to nestlings were Orthoptera,Julida,Araneae and Lepidoptera.Nestlings of the different species showed high interspecific diet overlap,indicating both a coincidence in growth needs among bird species and no or little limitation of the most profitable resources during the breeding season.Adults of all species showed higher diet richness than nestlings,and age-related differences in prey composition were mainly driven by the selection of the most easily digestible,larger protein-and calcium-rich prey for nestlings,which may favour their rapid growth,and avoiding highly sclerotized and less nutritional prey such as ants.Our study sheds light on the basic ecology and conservation of these declining steppe birds,indicating that interspecific competition may not be a major factor during the breeding season.Given the current global decline of arthropods,further long-term research would be necessary,along with the implementation of effective conservation measures that ensure a sufficient availability of resources identified as key prey in the diet of steppe bird nestlings.
基金Supported by the National Natural Science Foundation of China (Grant Nos.10771028 60533060)+1 种基金the programof New Century Excellent Fellowship of NECCfunded by a DoD fund (Grant No.DAAD19-03-1-0375)
文摘Multivariate spline function is an important research object and tool in Computational Geometry. The singularity of multivariate spline spaces is a difficult problem that is ineritable in the research of the structure of multivariate spline spaces. The aim of this paper is to reveal the geometric significance of the singularity of bivariate spline space over Morgan-Scott type triangulation by using some new concepts proposed by the first author such as characteristic ratio, characteristic mapping of lines （or ponits）, and characteristic number of algebraic curve. With these concepts and the relevant results, a polished necessary and sufficient conditions for the singularity of spline space S u＋1^u （△MS^u） are geometrically given for any smoothness u by recursion. Moreover, the famous Pascal＇s theorem is generalized to algebraic plane curves of degree n≥3.
