考虑风险规避的秘书问题求解的一个启发式方法

秘书问题是一类序贯观察与选择问题,描述了动态的信息搜索与决策过程.针对现有的以寻找满意解为目标的启发式方法存在诸多局限,提出了新的启发式方法,该方法基于当前观测中侯选项在已观察侯选项中的相对排名、待观测侯选项数量以及决策者的抱负水平,决策者可以通过设定抱负水平灵活决定该启发式方法的结果导向.推导了该启发式方法的性能指标,并通过仿真的方法与已有启发式方法的性能进行了比较.结果发现,该启发式方法在最终选择的侯选项的期望排名和稳定性,以及风险解的避免上均优于已有的启发式方法.     

哪些创业失败者更可能卷土重来?———基于松 － 紧文化与制度环境的跨国比较研究

高失败率是创业热潮中创业者必须面对的基本事实.创业失败在为创业者带来大量情绪与财务成本的同时,也提供了独特的学习经验.如何激活创业失败者卷土重来的激情是降低创业社会成本的关键.文章整合组织学习和创业认知理论构建了统一的创业失败学习理论逻辑,结合全球创业观察(Global Entrepreneurship Monitor)、世界银行和松-紧文化3个跨国数据库,考察了不同国家文化与制度环境下不同性别个体的创业失败经历对其创业选择的影响.研究发现:与没有失败经历的个体相比,有创业失败经历的个体更可能选择创业;高宽松度的国家文化、好的制度环境分别强化了这一关系;性别与文化宽松度对这一关系有显著的三重调节效应.即在高宽松度的国家文化下,有创业失败经历的女性创业者再次创业的概率更高.将性别角色差异纳入到创业失败的分析框架中,同时也扩展了创业失败的文化与制度分析.     

An upper bound on the minimal total cost of the transportation problem with varying demands and supplies

In general cases, to find the exact upper bound on the minimal total cost of the transportation problem with varying demands and supplies is an NP-hard problem. In literature, there are only two approaches with several shortcomings to solve the problem. In this paper, the problem is formulated as a bi-level programming model, and proven to be solvable in a polynomial time if the sum of the lower bounds for all the supplies is no less than the sum of the upper bounds for all the demands; and a heuristic algorithm named TPVDS-A based on genetic algorithm is developed as an efficient and robust solution method of the model. Computational experiments on benchmark and new randomly generated instances show that the TPVDS-A algorithm outperforms the two existing approaches.     

A shelf-space optimization model when demand is stochastic and space-elastic

The more customer demand is impulse-driven, the more it is space-dependent and the more it is subject to variation. We investigate the corresponding problem of retail shelf-space planning when demand is stochastic and sensitive to the number and position of facings. We develop a model to maximize a retailer׳s profit by selecting the number of facings and their shelf position under the assumption of limited space. The model is particularly applicable to promotional or temporary products.We develop the first optimization model and solution approach that takes stochastic demand into account, since the current literature applies deterministic models for shelf-space planning. By the means of an innovative modeling approach for the case with space- and positioning effects and the conversion of our problem into a mixed-integer problem, we obtain optimal results within very short run times for large-scale instances relevant in practice. Furthermore, we develop a solution approach to account for cross-space elasticity, and solve it using an own heuristic, which efficiently yields near-optimal results. We demonstrate that correctly considering space elasticity and demand variation is essential. The corresponding impacts on profits and solution structures become even more significant when space elasticity and stochastic demand interact, resulting in up to 5% higher profits and up to 80% differences in solution structures, if both effects are correctly accounted for. We develop an efficient modeling approach, compare the model results with approaches applied in practice and derive rules-of-thumb for planners.     

Model selection consistency of U-statistics with convex loss and weighted lasso penalty

In the paper we consider minimisation of U-statistics with the weighted Lasso penalty and investigate their asymptotic properties in model selection and estimation. We prove that the use of appropriate weights in the penalty leads to the procedure that behaves like the oracle that knows the true model in advance, i.e. it is model selection consistent and estimates nonzero parameters with the standard rate. For the unweighted Lasso penalty, we obtain sufficient and necessary conditions for model selection consistency of estimators. The obtained results strongly based on the convexity of the loss function that is the main assumption of the paper. Our theorems can be applied to the ranking problem as well as generalised regression models. Thus, using U-statistics we can study more complex models (better describing real problems) than usually investigated linear or generalised linear models.     

中国地方NGO生成机制的制度分析

地方NGO作为一种具体制度安排,其生成机制主要是在外在制度环境的作用下,以潜在利益为基本诱因,外在制度需求与内在制度供给相互契合推进,从而激励地方公民合作创设NGO制度安排的复杂过程。这是中国地方NGO生成的简要逻辑。从制度需求与制度供给的视角分析,在中国地方NGO的生成机制中,国家与市场对NGO制度安排的供给、市民集体行动的理性选择、地方制度转型的适应性安排、地方政府之间的制度竞争、地方知识精英的主导性介入与网络等科学技术进步的推动是六个关键性因素。特别是国家与市场的博弈过程与中国地方NGO的发展壮大过程相伴相生。分析中国地方NGO的生成机制,可以窥见中国公民社会的生长与发展轨迹。     

分支问题等价的一个充分条件

利用奇点理论的思想和方法研究了具有平凡解的分支问题．在t-等价群作用下,得到了具有平凡解的分支问题等价的充分条件．     

人大监督不力的制度原因探析

人大监督权运作正常与否被看成是衡量人大制度健康与否的重要标志。现阶段,我国各级人大较为普遍地存在着监督权不到位、监督不力的现象,这极大地消解了国家权力机关的权威、弱化了其地位。造成这一状况的制度原因主要有：党的领导和人大权力关系未能理顺;人大代表的筛选与监控机制失灵;人大代表履职监督机制还不够健全等。为此,解决人大监督不力、提高人大监督实效,要从制度建设入手,通过制度变革来形成合力,改变人大监督的政治生态环境,健全人大制度、强化人大监督,推动人大制度的健康发展。     

论制度变迁的动力机制与中国特色社会主义

加强对制度变迁的动力机制研究对于推动社会发展与转型、制度变迁与创新具有重要意义.生产力与生产关系的矛盾运动是制度变迁的最终决定力量,决定了中国特色社会主义必须坚持把发展作为党执政兴国的第一要务,人的需求与发展对制度变迁与创新起根本的推动作用,决定了中国特色社会主义必须坚持以人为本,社会意识形态是制度变迁的推动力量,决定了中国特色社会主义必须建立社会主义核心价值体系,自然环境和社会环境是制度变迁的外部力量,决定了中国特色社会主义必须加强生态保护和社会建设.     

On construction of asymptotically correct confidence intervals

In this paper we discuss constructing confidence intervals based on asymptotic generalized pivotal quantities (AGPQs). An AGPQ associates a distribution with the corresponding parameter, and then an asymptotically correct confidence interval can be derived directly from this distribution like Bayesian or fiducial interval estimates. We provide two general procedures for constructing AGPQs. We also present several examples to show that AGPQs can yield new confidence intervals with better finite-sample behaviors than traditional methods.