最优Steiner树问题(Steiner tree problem,STP)是一个经典的组合优化问题,许多工程问题都可以归结为最优Steiner树问题。STP被广泛应用于通信网络、电路设计、VLSI设计等领域。然而,STP是典型的NP难问题,还没有多项式时间的精确算法求...最优Steiner树问题(Steiner tree problem,STP)是一个经典的组合优化问题,许多工程问题都可以归结为最优Steiner树问题。STP被广泛应用于通信网络、电路设计、VLSI设计等领域。然而,STP是典型的NP难问题,还没有多项式时间的精确算法求解该问题。目前,求解该问题的算法主要集中在基于启发式的近似算法、智能优化算法、信息传播算法等,并取得了很好的效果。在不同规模的网络中,基于传统遗传算法给出一种叶交叉机制(leaf crossover,LC),使用该机制的算法性能表现更好。通过对这些算法的原理、性能、精度等方面进行梳理,归纳出算法的优缺点,并指出STP的研究方向和算法设计路径,对于相关问题的研究有指导意义。展开更多
A t-(v,k,λ)design(X,B)is a set X of points,of cardinality v,and a collection B of k-subsets of X called blocks,with the property that every t-subset of X is contained in precisely λ blocks.A t-design is a t-(v,k,λ)...A t-(v,k,λ)design(X,B)is a set X of points,of cardinality v,and a collection B of k-subsets of X called blocks,with the property that every t-subset of X is contained in precisely λ blocks.A t-design is a t-(v,k,λ) design for some v,k,γ.In this paper,we give a generalization of t-design called balanced n-ary t-design,and obtain some properties of the new combinatorial structure.展开更多
This study aims to discuss the possibility of becoming conscious of certain aspects of one’s own existence through creative activity.The discussion involves Piagetian constructivism and Steiner’s ideas about human d...This study aims to discuss the possibility of becoming conscious of certain aspects of one’s own existence through creative activity.The discussion involves Piagetian constructivism and Steiner’s ideas about human development and is justified by the contribution of creative activity to the development of autonomy,according to Piaget,and to the development of an ethical individuality,according to Steiner.The participation of adults in sessions of creative process,as well as the questions posed after this activity,asking for the relationships between what they created and their life,is evidence of practices favourable to increasing the grasping of consciousness of self and of the process of developing an ethical individuality.展开更多
文摘最优Steiner树问题(Steiner tree problem,STP)是一个经典的组合优化问题,许多工程问题都可以归结为最优Steiner树问题。STP被广泛应用于通信网络、电路设计、VLSI设计等领域。然而,STP是典型的NP难问题,还没有多项式时间的精确算法求解该问题。目前,求解该问题的算法主要集中在基于启发式的近似算法、智能优化算法、信息传播算法等,并取得了很好的效果。在不同规模的网络中,基于传统遗传算法给出一种叶交叉机制(leaf crossover,LC),使用该机制的算法性能表现更好。通过对这些算法的原理、性能、精度等方面进行梳理,归纳出算法的优缺点,并指出STP的研究方向和算法设计路径,对于相关问题的研究有指导意义。
文摘A t-(v,k,λ)design(X,B)is a set X of points,of cardinality v,and a collection B of k-subsets of X called blocks,with the property that every t-subset of X is contained in precisely λ blocks.A t-design is a t-(v,k,λ) design for some v,k,γ.In this paper,we give a generalization of t-design called balanced n-ary t-design,and obtain some properties of the new combinatorial structure.
文摘This study aims to discuss the possibility of becoming conscious of certain aspects of one’s own existence through creative activity.The discussion involves Piagetian constructivism and Steiner’s ideas about human development and is justified by the contribution of creative activity to the development of autonomy,according to Piaget,and to the development of an ethical individuality,according to Steiner.The participation of adults in sessions of creative process,as well as the questions posed after this activity,asking for the relationships between what they created and their life,is evidence of practices favourable to increasing the grasping of consciousness of self and of the process of developing an ethical individuality.
