Lower bounds and a tabu search algorithm for the minimum deficiency problem

An edge coloring of a graph G=(V,E) is a function c:E→ℕ that assigns a color c(e) to each edge e∈E such that c(e)≠c(e′) whenever e and e′ have a common endpoint. Denoting S _v (G,c) the set of colors assigned to the edges incident to a vertex v∈V, and D _v (G,c) the minimum number of integers which must be added to S _v (G,c) to form an interval, the deficiency D(G,c) of an edge coloring c is defined as the sum ∑ _v∈V D _v (G,c), and the span of c is the number of colors used in c. The problem of finding, for a given graph, an edge coloring with a minimum deficiency is NP-hard. We give new lower bounds on the minimum deficiency of an edge coloring and on the span of edge colorings with minimum deficiency. We also propose a tabu search algorithm to solve the minimum deficiency problem and report experiments on various graph instances, some of them having a known optimal deficiency.     

Agent Rationality Behind Network Formation

We search for agent behavior rules which lead to the emergence of social networks that exhibit empirically observed phenomena: small-world property, scale-free degree distribution and stability in time. We assume that agents form and sever links using a cost-benefit analysis. Agents receive benefit from own links and from links that their friends form. On the other hand, link formation, deletion and keeping is costly. We find that a simple model structure which relies only on convex cost of link upkeep leads to stable networks which exhibit the small-world property.     

跨界搜索、企业内部协作网络与创新产出技术影响力：基于全球半导体行业的实证分析

本研究通过对全球半导体行业1991-2000年间64家上市公司样本,实证检验跨界搜索对创新产出技术影响力的作用关系,及企业内部协作网络整合度对跨界搜索有效性的调节机制。本研究认为,企业内部协作网络,作为企业重要的非正式组织,直接影响组织内部知识交换过程,进而影响跨界搜索的有效性。结果发现：（1）跨界搜索对创新产出技术影响力存在倒U性关系;（2）协作网络整合度越高,跨界搜索对创新产出技术影响力的正影响就越强。     

自动化立体仓库中的储位分配及存取路径优化

储位分配和存取作业路径优化是仓储管理中的两个重要决策问题。本文研究如何在自动化立体仓库中对这两个问题进行同时决策。提出了一个混合整数规划模型对该问题进行优化建模,设计开发了一个基于有向连接图的两阶段优化算法对问题求初始解,并利用禁忌搜索算法对所求得的解进行改进。算法第一阶段解决储位分配问题,在此基础上第二阶段利用Hungarian算法对堆垛机的存取作业路径优化问题进行求解。最后利用实例对算法效率和精度进行分析评价,计算结果验证了算法的有效性。     

具有遗憾值约束的鲁棒供应链网络设计模型研究

考虑不确定性环境,研究战略层次的供应链网络鲁棒设计问题,目标是设计参数发生摄动时,供应链性能能够保持稳健性。基于鲁棒解的定义,建立从上游供应商选择到下游设施选址-需求分配的供应链网络设计鲁棒优化模型;提出确定遗憾值限定系数上限和下限的方法,允许决策者调节鲁棒水平,选择多种供应链网络结构;通过模型分解与协调,设计了供应链节点配置的禁忌搜索算法。算例的计算结果表明了禁忌搜索算法具有良好的收敛特性,以及在处理大规模问题上的优越性;同时也反映了利用鲁棒优化模型进行供应链网络设计,可以有效规避投资风险。     

Incentives in a Stage‐Gate Process

Many large organizations use a stage‐gate process to manage new product development projects. In a typical stage‐gate process project managers learn about potential ideas from research and exert effort in development while senior executives make intervening go/no‐go decisions. This decentralized decision making results in an agency problem because the idea quality in early stages is unknown to the executive and the project manager must exert unobservable development effort in later stages. In light of these challenges, how should the firm structure incentives to ensure that project managers reveal relevant information and invest the appropriate effort to create value? In this study, we develop a model of adverse selection in research and moral hazard in development with a go/no‐go decision at the intervening gate. Our results show that the principal's uncertainty regarding early‐stage idea quality—a term we refer to as idea risk—alters the effect of late‐stage development risk. The presence of idea risk can alter the incentives offered to the agent and may lead the principal to reject projects that otherwise seem favorable in terms of positive net present value. A simulation of early‐stage ideas, found through search on a complex landscape, shows that the firm can mitigate the negative effects of idea risk by encouraging breadth of search and high tolerance for failure.     

对共轭梯度法中标量β_k的一种修正

共轭梯度法是优化算法中最常用的方法之一,适于解决大规模问题,因而有着广泛的应用,而标量kβ不同的选取可以构成不同的共轭梯度法。修正了共轭梯度法中的标量kβ,将其推广到一般情况,并在wolfe线搜索下证明了它的全局收敛性。     

我国水资源管理与水系统科学发展的机遇与挑战

针对国家重大需求和国际科学前沿问题,综述了中国水资源管理与水系统科学发展面临的机遇与挑战。初步论述了聚焦在水资源的前瞻性、战略性和交叉性的研究的三个发展方向,指出了变化环境的水问题所涉及到水与气候、水与生态、水与环境、水与社会及其联系的复杂水系统问题,强调了水系统科学的发展及其在应对复杂水问题的科学基础支撑与管理的指导作用。建议加强水系统的科学基础理论研究与创新＂、水与气候＂＂水与生态＂＂水与社会＂应用问题的综合研究和水系统科学与水资源管理的交叉研究。     

蒙古游牧社会变迁与“蒙古族村落群”成因关系追溯

以连带性视角回顾历史上蒙古人的盛衰与荣辱体验,特别是历数历代统治阶级对蒙古族所实行的民族歧视政策的同时,试图以不偏不倚的公正思维,盘点反其道而行的蒙古游牧社会变迁的另类历史轨迹;同时以“历史欠账”与当今蒙古族聚居区生存条件捆绑探究的新视点,揭秘蒙古游牧社会变迁与当今蒙古族村落群形成的因果关系;进而把一直被忽略的历史原因为诉说理由,使其确认为致使蒙古族滞后的一项分量很重的客观因素。     

吉林省农业科技园区建设存在的问题和对策

文章从吉林省农业科技园区的发展成果出发,总结了搞好农业园区建设的重要意义和作用。根据目前农业科技园区运行的现状和存在的问题,探讨了今后的发展方向,提出了有针对性的发展策略。