We address the 1-line minimum Steiner tree of line segments(1L-MStT-LS)problem.Specifically,given a set S of n disjoint line segments in R^(2),we are asked to find the location of a line l and a set E_(l) of necessary...We address the 1-line minimum Steiner tree of line segments(1L-MStT-LS)problem.Specifically,given a set S of n disjoint line segments in R^(2),we are asked to find the location of a line l and a set E_(l) of necessary line segments(i.e.,edges)such that a graph consisting of all line segments in S ∪ E_(l) plus this line l,denoted by T_(l)=(S,l,E_(l)),becomes a Steiner tree,the objective is to minimize total length of edges in E_(l) among all such Steiner trees.Similarly,we are asked to find a set E_(0) of necessary edges such that a graph consisting of all line segments in S ∪ E_(0),denoted by T_(S)=(S,E_(0)),becomes a Steiner tree,the objective is to minimize total length of edges in E_(0) among all such Steiner trees,we refer to this new problem as the minimum Steiner tree of line segments(MStT-LS)problem.In addition,when two endpoints of each edge in Eo need to be located on two different line segments in S,respectively,we refer to that problem as the minimum spanning tree of line segments(MST-LS)problem.We obtain three main results:(1)Using technique of Voronoi diagram of line segments,we design an exact algorithm in time O(n log n)to solve the MST-LS problem;(2)we show that the algorithm designed in(1)is a 1.214-approximation algorithm to solve the MStT-LS problem;(3)using the combination of the algorithm designed in(1)as a subroutine for many times,a technique of finding linear facility location and a key lemma proved by techniques of computational geometry,we present a 1.214-approximation algorithm in time O(n^(3) log n)to solve the 1L-MStT-LS problem.展开更多
The Euclidean Steiner minimum tree problem is a classical NP-hard combinatorial optimization problem.Because of the intrinsic characteristic of the hard computability,this problem cannot be solved accurately by effici...The Euclidean Steiner minimum tree problem is a classical NP-hard combinatorial optimization problem.Because of the intrinsic characteristic of the hard computability,this problem cannot be solved accurately by efficient algorithms up to now.Due to the extensive applications in real world,it is quite important to find some heuristics for it.The stochastic diffusion search algorithm is a newly population-based algorithm whose operating mechanism is quite different from ordinary intelligent algorithms,so this algorithm has its own advantage in solving some optimization problems.This paper has carefully studied the stochastic diffusion search algorithm and designed a cellular automata stochastic diffusion search algorithm for the Euclidean Steiner minimum tree problem which has low time complexity.Practical results show that the proposed algorithm can find approving results in short time even for the large scale size,while exact algorithms need to cost several hours.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11861075 and 12101593)Project for Innovation Team(Cultivation)of Yunnan Province(No.202005AE160006)+2 种基金Key Project of Yunnan Provincial Science and Technology Department and Yunnan University(No.2018FY001014)Program for Innovative Research Team(in Science and Technology)in Universities of Yunnan Province(No.C176240111009)Jian-Ping Li is also supported by Project of Yunling Scholars Training of Yunnan Province.Su-Ding Liu is also supported by the Graduate Research and Innovation Project of Yunnan University(No.2020Z66).
文摘We address the 1-line minimum Steiner tree of line segments(1L-MStT-LS)problem.Specifically,given a set S of n disjoint line segments in R^(2),we are asked to find the location of a line l and a set E_(l) of necessary line segments(i.e.,edges)such that a graph consisting of all line segments in S ∪ E_(l) plus this line l,denoted by T_(l)=(S,l,E_(l)),becomes a Steiner tree,the objective is to minimize total length of edges in E_(l) among all such Steiner trees.Similarly,we are asked to find a set E_(0) of necessary edges such that a graph consisting of all line segments in S ∪ E_(0),denoted by T_(S)=(S,E_(0)),becomes a Steiner tree,the objective is to minimize total length of edges in E_(0) among all such Steiner trees,we refer to this new problem as the minimum Steiner tree of line segments(MStT-LS)problem.In addition,when two endpoints of each edge in Eo need to be located on two different line segments in S,respectively,we refer to that problem as the minimum spanning tree of line segments(MST-LS)problem.We obtain three main results:(1)Using technique of Voronoi diagram of line segments,we design an exact algorithm in time O(n log n)to solve the MST-LS problem;(2)we show that the algorithm designed in(1)is a 1.214-approximation algorithm to solve the MStT-LS problem;(3)using the combination of the algorithm designed in(1)as a subroutine for many times,a technique of finding linear facility location and a key lemma proved by techniques of computational geometry,we present a 1.214-approximation algorithm in time O(n^(3) log n)to solve the 1L-MStT-LS problem.
基金the National Natural Science Foundation of China (No.70871081)the Science and Technology Department Research Project of Henan Province(No.112102310448)the Natural Science Foundation of Henan University (No.2010YBZR047)
文摘The Euclidean Steiner minimum tree problem is a classical NP-hard combinatorial optimization problem.Because of the intrinsic characteristic of the hard computability,this problem cannot be solved accurately by efficient algorithms up to now.Due to the extensive applications in real world,it is quite important to find some heuristics for it.The stochastic diffusion search algorithm is a newly population-based algorithm whose operating mechanism is quite different from ordinary intelligent algorithms,so this algorithm has its own advantage in solving some optimization problems.This paper has carefully studied the stochastic diffusion search algorithm and designed a cellular automata stochastic diffusion search algorithm for the Euclidean Steiner minimum tree problem which has low time complexity.Practical results show that the proposed algorithm can find approving results in short time even for the large scale size,while exact algorithms need to cost several hours.
基金国家自然科学基金(the National Natural Science Foundation of China under Grant No.70471065)上海市重点学科建设项目(the Shanghai Leading Academic Discipline Project No.T0502)
