A reactive tabu search algorithm for the vehicle routing problem with simultaneous pickups and deliveries

The vehicle routing problem with pickups and deliveries (VRPPD) extends the vehicle routing problem (VRP) by allowing customers to both send and receive goods. The main difficulty of the problem is that the load of vehicles is fluctuating rather than decreasing as in the VRP. We design a reactive tabu search metaheuristic that can check feasibility of proposed moves quickly and reacts to repetitions to guide the search. Several new best solutions are found for benchmark problems.     

北京高校毕业生求职的资源动员行为分析

本文依据北京高校毕业生的实证调研数据,分析了大学生求职资源动员行为的结构与特征。研究发现:动员校内资源是中国大学生重要的求职行为;在所属高校层级、自身校内资源和生源地等指标上,不同毕业生群体的资源动员行为存在显著性差异。     

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。     

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。     

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。     

基于需求预测的两级动态配送路径优化研究

针对传统响应式配送难以应对海量动态客户需求的困境,在此提出基于需求预测的两级动态配送路径优化方法。利用历史数据从需求预测、需求聚类和需求配额三个维度,处理电商物流配送过程中的动态需求;建立基于需求预测的单阶段和多阶段两级车辆配送路径优化模型,并针对问题特性利用分支定界算法与CW-禁忌搜索算法生成两个阶段的最优配送路径。最后结合实验案例对模型与算法的有效性进行验证,试验结果表明本文设计方法具有较好的动态场景适应度和客户响应能力。     

网络信息的分类

网络信息浩如烟海,分类五花八门,依据传统文献信息分类法的科学性和系统性对其进行分类非常重要。本文就网络信息分类特点及其信息分类中存在的问题进行探讨,对建设统一的网络信息分类体系提出了自己的看法。