A {{10}}-Approximation Algorithm for a Generalization of the Weighted Edge-Dominating Set Problem

We study the approximability of the weighted edge-dominating set problem. Although even the unweighted case is NP-Complete, in this case a solution of size at most twice the minimum can be efficiently computed due to its close relationship with minimum maximal matching; however, in the weighted case such a nice relationship is not known to exist. In this paper, after showing that weighted edge domination is as hard to approximate as the well studied weighted vertex cover problem, we consider a natural strategy, reducing edge-dominating set to edge cover. Our main result is a simple -approximation algorithm for the weighted edge-dominating set problem, improving the existing ratio, due to a simple reduction to weighted vertex cover, of 2r _WVC, where r _WVC is the approximation guarantee of any polynomial-time weighted vertex cover algorithm. The best value of r _WVC currently stands at . Furthermore we establish that the factor of is tight in the sense that it coincides with the integrality gap incurred by a natural linear programming relaxation of the problem.     

论“三个代表”中“文化”的本源思想及思考视角

代表"中国先进的文化方向"是执政党群体的行为准则,是走向21世纪中国文化发展的象征.然而,"文化"一词的本源思想是什么?将对我们理解"代表"的真正含义,起到举足轻重的作用;用什么视角来思考"文化方向",又是我们落实"代表"思想的关键环节.     

角度单值-移动合向量长度控制图

基于角度技术标准,研究总体质量特性值服从V on M ises分布M(μ0,k)的角度质量控制问题。应用方向数据统计方法,从平均方向和合向量长度的概念出发,研究角度单值的分布和移动合向量长度的分布,给出标准值给定和标准值未给定两种情况下角度单值控制图和移动合向量长度控制图的控制限。测算结果表明V on M ises分布M(μ0,k)的刻度参数对控制限的大小起着关键作用。     

On Split-Coloring Problems

We study a new coloring concept which generalizes the classical vertex coloring problem in a graph by extending the notion of stable sets to split graphs. First of all, we propose the packing problem of finding the split graph of maximum size where a split graph is a graph G = (V,E) in which the vertex set V can be partitioned into a clique K and a stable set S. No condition is imposed on the edges linking vertices in S to the vertices in K. This maximum split graph problem gives rise to an associated partitioning problem that we call the split-coloring problem. Given a graph, the objective is to cover all his vertices by a least number of split graphs. Definitions related to this new problem are introduced. We mention some polynomially solvable cases and describe open questions on this area. An erratum to this article is available at .     

尘埃如何落定--试析《尘埃落定》的叙述

<尘埃落定>的成功,很大程度上得益于叙述的成功.从"傻子"二少爷的第一人称叙述角度的选择、叙述时间的快慢蕴涵作家价值取向以及叙述的思维跳跃性、预言性、短句为主的语言和意象性等所体现出来的诗意渗透等方面对<尘埃落定>的叙述进行分析,以期对这部小说进行更准确的解读.     

新历史小说“新”论

新历史小说以实验文本的形式走上当代文坛,繁荣一时,但至今为止还是一个含混的概念,从历史题材、历史视角、历史意识三个角度入手,尝试澄清它与十七年时期革命历史小说和传统历史小说的区别以及“新”之所在,为它的存在提供理由与合法性依据,并对简单地将新历史小说与新历史主义理论对应阐释的状况提出批评。     

新文学源流的政治文化再考

0世纪中国文学的源流、传统问题 ,似乎已有了文学史的定论。但是 ,过往的认识 :一是从文学是社会生活的反映或再现考察其演变 ;一是从文学本身的表现中寻求文学本质或规律。近代中国文学自觉与不自觉地走进了政治的系统中寻求生路 ,她不同于简单化的“政治”概念 ,很大程度是政治的心理诉求和文学精神现象的互动认知。新文学源流应该是 ,“文学救国”与“文学革命”所表现的特殊文化语境中的整合现象 ,是文学载体与历史转型交织生成的过程     

关于短跑运动员下肢技术的研究

本文通过对跑的两个时期的分析认为后趴力，后划力，伸踝力是推动人体向前运动的真正动力，充分的后蹬是没有意义．     

仿射李代数C_3~((1))的一类顶点表示

通过引进一系列顶点算子,构造了访射李代数C_3~((I))的一类水平为1的不可约最高权表示。     

分离式热管卧式加热段传热性能的实验研究

对分离式热管卧式加热段进行了传热性能实验,考察了充液率、倾角对卧式加热段传热性能的影响,由实验数据回归得出无因次换热准则关系式。