The densest <Emphasis Type="Italic">k</Emphasis>-subgraph problem on clique graphs

The Densest k-Subgraph (DkS) problem asks for a k-vertex subgraph of a given graph with the maximum number of edges. The problem is strongly NP-hard, as a generalization of the well known Clique problem and we also know that it does not admit a Polynomial Time Approximation Scheme (PTAS). In this paper we focus on special cases of the problem, with respect to the class of the input graph. Especially, towards the elucidation of the open questions concerning the complexity of the problem for interval graphs as well as its approximability for chordal graphs, we consider graphs having special clique graphs. We present a PTAS for stars of cliques and a dynamic programming algorithm for trees of cliques. M.L. is co-financed within Op. Education by the ESF (European Social Fund) and National Resources. V.Z. is partially supported by the Special Research Grants Account of the University of Athens under Grant 70/4/5821.     

Design and implementation of an integrated production planning system for a pharmaceutical manufacturing concern in India

SmithKline Beecham (SBPI) is a major player in the Indian pharmaceutical industry. Though relatively small in terms of turnover, it has performed Pharmaceuticals (India) exceptionally well in terms ofprofitability and growth rate. The firm has substantial cash reserves. However, the firm operates in 'mass production' mode at present, with the established finished goods inventory norms being in the range of 1 to 1.5 months. Competitive pressure on the firm is now forcing it to move towards world class manufacturing and the application of concepts from MRP II, JIT and OPT is under consideration. This paper describes the considerations that went into the justification, design and implementation of an integrated production planning and control system in this situaion.     

论大学英语课堂评估方式及其对教学的反拨作用

适时、适量、适度的大学英语课堂评估能有效地促进大学英语教学.大学英语课堂评估的形式可分为测试性与非测试性两类,非测试性方式有课堂观察、学习档案、日志等,在当前比较注重学生英语运用能力的教学中,非测试手段尤为重要.在测试性方式中,随堂测试、诊断测试、成绩测试等都可选用.如果进行得恰当,课堂评估对教学会产生多方面的积极反拨作用.     

多媒体技术在连串反应动力学教学中的应用

利用Matlab语言中Simulink工具 ,开发了连串反应动力学过程动态模拟多媒体功能模块 ,并将其应用于教学中 ,效果良好。     

浅论学生思想品德教育

本文首先从青少年成长、中国21世纪发展和应对国际大环境需要的角度，论述了加强学生思想教育的紧迫性；接着分析了社会舆论导向的三个认识误区；并提出了把静态教育变为动态教育的改革建议。     

学生授课PK法在大学课堂教学中的运用

大学课堂大多以教师讲授为主,很难听到学生的观点与异议,学生的主动性与积极性难以激发,学习效果受到严重影响。本文提出一种提高大学课堂学习效果的学生授课PK法,这种方法将改变教师一贯唱主角的教学模式,同时提高学生参与学习的主动性、积极性。     

An illustration of dynamic network DEA in commercial banking including robustness tests

The main motivation of this article is to illustrate dynamic network data envelopment analysis (DN-DEA) in commercial banking with emphasis on testing robustness. To this end, sixteen foreign banks in China are benchmarked against thirty-two domestic banks for the post-2007 period that follows major reforms. When network and dynamic dimensions are brought together, a more comprehensive analysis of the period 2008–2010 is enabled where divisional and between-period interactions are reflected in efficiency estimates. Weighted, variable returns-to-scale, non-oriented dynamic network slacks-based measure is used within the framework of the intermediation approach to bank behavior. A bank network (i.e., a decision-making unit, DMU) is conceptualized as comprised of two divisions or sub-DMUs, namely, interest-bearing operations and non-interest operations linked by number of referrals. Undesirable outputs from sub-DMUs 1 and 2 (non-performing loans, and proportion of fruitless referrals, respectively) are treated as carry-overs that impact the efficiency of the following periods. Under robustness testing, the illustrative application discusses discrimination by efficiency estimates, dimensionality of the performance model, stability of estimates through re-sampling (leave-one-out method), and sensitivity of results to divisional weights and returns-to-scale assumptions. The results based on Chinese commercial banks are illustrative in nature because of simulated data used on two of the variables.     

Managing stochastic demand in an Inventory Routing Problem with transportation procurement

We study an Inventory Routing Problem in which the supplier has a limited production capacity and the stochastic demand of the retailers is satisfied with procurement of transportation services. The aim is to minimize the total expected cost over a planning horizon, given by the sum of the inventory cost at the supplier, the inventory cost at the retailers, the penalty cost for stock-out at the retailers and the transportation cost. First, we show that a policy based just on the average demand can have a total expected cost infinitely worse than the one obtained by taking into account the overall probability distribution of the demand in the decision process. Therefore, we introduce a stochastic dynamic programming formulation of the problem that allows us to find an optimal policy in small size instances. Finally, we design and implement a matheuristic approach, integrating a rollout algorithm and an optimal solution of mixed-integer linear programming models, which is able to solve realistic size problem instances. Computational results allow us to provide managerial insights concerning the management of stochastic demand.     

Dynamic Bayesian analysis of generalized odds ratios assuming multivariate skew-normal distribution for the error terms in the system equation

In this paper, we develop a methodology for the dynamic Bayesian analysis of generalized odds ratios in contingency tables. It is a standard practice to assume a normal distribution for the random effects in the dynamic system equations. Nevertheless, the normality assumption may be unrealistic in some applications and hence the validity of inferences can be dubious. Therefore, we assume a multivariate skew-normal distribution for the error terms in the system equation at each step. Moreover, we introduce a moving average approach to elicit the hyperparameters. Both simulated data and real data are analyzed to illustrate the application of this methodology.     

中国碳交易政策扩散的影响因素、路径差异与减碳效果研究——基于省域数据的实证分析

碳交易市场的建设有助于实现全球碳平衡,而碳交易政策扩散对于促进中国碳交易市场的持续健康发展有着重要的现实意义。在我国碳交易市场建设不断深化的情境下,有必要识别省域碳交易政策扩散的多维影响要素,检验不同扩散路径下的政策效果差异,总结政策扩散经验。文章基于省域面板数据,首先运用事件史分析法,通过Cox比例风险模型发现,能源政策的落实、地方政府的综合服务能力和社会创新能力是碳交易政策扩散的关键驱动要素;其次,利用合成控制法进一步检验,发现主动扩散地区的减排效果弱于试点扩散地区,试点扩散地区对主动扩散地区的激励和带动作用有限,试点成果尚未得到有效学习和复制。为此,在我国统一碳交易市场的建设过程中,应强化中央统筹协调与地方相关举措之间的协同配合,依托有力的政策驱动激发我国碳交易制度活力,提升碳减排效果,形成路径清晰、梯度有序的政策扩散机制,以稳步实现2030“碳达峰”、2060“碳中和”的目标。