Scheduling two-stage production lines with multiple machines

Most manufacturing process maintain separate fabrication and assembly centres. Based on this observation, the author coincides a manufacturing process that contains two stages of production with multiple machines. The manufacturer produces a variety of products to satisfy customer demands, operates under a 'push' mode and in a ‘ make-to-order’ environment. Each customer order consists of known quantities of different products which must be delivered as a whole shipment. Periodically, the manufacturer schedules all the accumulated unscheduled customer orders. The scheduling objective is to minimize the sum of weighted customer order lead times. Such manufacturing systems are formulated as a mathematical programming problem. It is then shown that this problem is unary NP-hard and remains unary NP-hard even when all the weights are equal. Some insights about the structure of the optimal schedule(s) are provided and some special cases solved in polynomial time. Several polynomial time heuristics are proposed, and worst-case analysis of some of the heuristics are provided. Tight lower bounds are developed in order to measure the performance of the proposed heuristics. Numerical examples are presented and possible extensions are discussed.     

An effective total ranking model for a ranked voting system

In this paper an effective model to rank candidates in a preferential election is proposed. It is an extension and simplified form of a recently proposed model for ranking efficient candidates. The model consists of fewer constraints and can be used for ranking inefficient as well as efficient candidates. Some techniques are introduced to decrease the complexity of the proposed model by obtaining some of the results by inspection.     

Population Changes in Europe. Demographic and Social Prospects and Problems

Abstract. Over recent years, the European Community has experienced profound demographic changes which, to a large extent, have already determined its demographic future. One of the more significant consequences of demographic and social trends is a marked fragmentation of the family with people giving absolute priority to the individual dimension in their lives and in terms of society as a whole. Legal regulations and administrative practice have not totally–and not everywhere – adapted to the far-reaching changes in the family so as to adequately protect the family and its weaker members in particular: children, the elderly, the disabled, people with mental and social illnesses, the poor. In this field, some measures will be proposed in this paper. The imbalances in demographic-occupational growth in the Euro-Mediterranean area–the area with which the EC is most directly in contact–are and will be of an exceptional amplitude, as has already been shown, to an extent never before experienced in the history of mankind. We must ask ourselves if this very strong differential pressure, which is also of a political and socio-economic nature, will lead to steady and long-lasting migratory flows. Some considerations regarding the future action and intervention of the EC close the paper.     

GMM with Many Moment Conditions

This paper provides a first order asymptotic theory for generalized method of moments (GMM) estimators when the number of moment conditions is allowed to increase with the sample size and the moment conditions may be weak. Examples in which these asymptotics are relevant include instrumental variable (IV) estimation with many (possibly weak or uninformed) instruments and some panel data models that cover moderate time spans and have correspondingly large numbers of instruments. Under certain regularity conditions, the GMM estimators are shown to converge in probability but not necessarily to the true parameter, and conditions for consistent GMM estimation are given. A general framework for the GMM limit distribution theory is developed based on epiconvergence methods. Some illustrations are provided, including consistent GMM estimation of a panel model with time varying individual effects, consistent limited information maximum likelihood estimation as a continuously updated GMM estimator, and consistent IV structural estimation using large numbers of weak or irrelevant instruments. Some simulations are reported.     

The Effects of Task Information and Outcome Feedback on Individuals' Insight into Their Decision Models

When making business decisions, people generally receive some form of guidance. Often, this guidance might be in the form of instructions about which inputs to the decision are most important. Alternatively, it might be outcome feedback concerning the appropriateness of their decisions. When people receive guidance in making difficult judgments, it is important that they do not confuse this guidance with insight into their own decision models. This study examined whether people confuse their actual decision model with task information and outcome feedback. Subjects predicted the likelihood that various hypothetical companies would experience financial distress and then reported the decision models they believed they had used. Their reported models were compared with their actual models as estimated by a regression of the subjects' predictions on the inputs to their decisions. In a 2times2 factorial design, some subjects were provided with task information regarding the relative importance of each input to their decisions while others were not. Some subjects were provided with outcome feedback regarding the quality of their decisions while others were not. The subjects tended to confuse the task information and outcome feedback with their actual decision models. Implications for the results are discussed.     

Business games and implementation research

This paper reviews some recent research in OR implementation and suggests that a new approach is required, which will take fuller account of the perceptions of managers concerned with the problem. Research games in business settings seem to offer a means for such approach. Some lessons learned from a business game used in this way are described and their implications for modelbuilders are discussed.     

Technological forecasting in six major U.K. companies

This study, although based upon a small sample, generally supports the recent evidence in the U.K. and the United States concerning the state of current practice in technological forecasting. The weight of this evidence points to the conclusion that the formal techniques of TF are not widely practiced, although the need for TF is generally accepted, and that those companies which are using these techniques do so with some reservation. Some companies in the U.K., however, do have considerable experience in technological forecasting, diffusion of the knowledge of which would be of benefit to the bulk of British industry.     

管理科学中国学派如何走向世界？——问题、策略及系统方法论层面的分析

针对管理科学中国学派走向世界的需要,界定了管理科学中国学派的内涵和特色,分析了管理科学中国学派在走向世界过程中存在的问题,提出"通过寻找东西方管理的共同点,让管理科学中国学派走向世界"的策略;以西方的CmCvAwA s系统理论和东方的物理-事理-人理系统理论为例,分析了东西方在系统方法论层面上的相互联系,期望为管理科学中国学派走向世界提供借鉴。     

Data envelopment analysis: Prior to choosing a model

In this paper, we address several issues related to the use of data envelopment analysis (DEA). These issues include model orientation, input and output selection/definition, the use of mixed and raw data, and the number of inputs and outputs to use versus the number of decision making units (DMUs). We believe that within the DEA community, researchers, practitioners, and reviewers may have concerns and, in many cases, incorrect views about these issues. Some of the concerns stem from what is perceived as being the purpose of the DEA exercise. While the DEA frontier can rightly be viewed as a production frontier, it must be remembered that ultimately DEA is a method for performance evaluation and benchmarking against best-practice. DEA can be viewed as a tool for multiple-criteria evaluation problems where DMUs are alternatives and each DMU is represented by its performance in multiple criteria which are coined/classified as DEA inputs and outputs. The purpose of this paper is to offer some clarification and direction on these matters.     

论知识经济时代的人力资源管理

结合世界发达国家的知识经济的兴起 ,阐述了知识经济的特征及发展现状 ;分析了知识经济时代对人力资源要求的基本特征 ;进而 ,结合国情 ,提出了我国发展知识经济框架下人力资源管理的模式和策略 .它们可作为人力资源管理的高层决策的依据和参考 .     

Subset sum problems with digraph constraints

We introduce and study optimization problems which are related to the well-known Subset Sum problem. In each new problem, a node-weighted digraph is given and one has to select a subset of vertices whose total weight does not exceed a given budget. Some additional constraints called digraph constraints and maximality need to be satisfied. The digraph constraint imposes that a node must belong to the solution if at least one of its predecessors is in the solution. An alternative of this constraint says that a node must belong to the solution if all its predecessors are in the solution. The maximality constraint ensures that no superset of a feasible solution is also feasible. The combination of these constraints provides four problems. We study their complexity and present some approximation results according to the type of input digraph, such as directed acyclic graphs and oriented trees.     

Leadership of socio-political vanguards: A review and future directions

With the influential rise of the Alt-Right throughout the West in recent years, there has been a renewed interest in the leadership of these forms of fringe political groups. While some work on the leadership of these types of groups was done in the 1960s, 70s, and 80s, less work has been done since then. Given the important role of these groups in today's political environment, a review and theoretical integration of this past leadership work, along with suggestions for future research directions, is overdue.This paper begins by reviewing what literature exists regarding the leadership of socio-political vanguards, as well as what additional literature exists that may also be relevant to better understanding the phenomenon of vanguard leadership. Vanguard leadership is then placed within the historical context and goals of past vanguard groups. This analysis then leads to further defining some of the components of vanguard leadership along with a review of typically associated leadership traits, skills and behaviours.While few theories directly address the way in which vanguard leadership operates, this paper reviews related leadership theories that might offer meaningful contributions to our understanding of socio-political vanguard leadership. Some theories, such as those related to social movements (particularly burgeoning), minor but influential mainstream political groups, and advocacy/activist collectives are particularly relevant here and are reviewed along with more general leadership theories that might also hold applicability, such as those related to leader and follower (and public) information processing and sensemaking under crises. The paper then concludes with some suggestions for future research directions.     

Recycling resources

The current rate of depletion of non-renewable resources and of the generation of waste for disposal have prompted the call for waste to be reclaimed and re-used.This paper describes the general forms which such recycling presently takes and identified the factors which bear upon the amount and nature of recycling. Some of these factors are seen to be economic, others technological and behavioural. Although a private enterprise economy will automatically recycle resources in some degree, the author concludes that the analysis presented here of the relevant determinants of recycling suggests that conscious intervention of some kind is desirable.     

The planning of a department store

A town or village attracts people from its hinterland to purchase goods by virtue of the amount and variety of goods on offer. Similarly, a department store attracts customers away from cempetitors by means of displays, staff expertise, stock holdings and numerous other parameters. The store is generally free to manipulate these parameters subject to certain restrictions; the manipulation will have a direct affect on the ultimate profitability of the store. This paper describes some current research that is being carried out in conjunction with a department store group. The ultimate aim is to link the corporate planning of the group and each store to detailed socioeconomic data describing the population. Some aspects of the problem have been investigated in depth, some are currently being discussed and some have not been considered at all as yet. The latest position will be reported and hopefully some feedback will be engendered.     

Some trends in corporate modelling

This paper reviews the evidence of a number of surveys and case studies of corporate modelling in the U.K. Some general conclusions as to trends are drawn. Thus corporate models will display increasing modularity; will be more likely to include probabilistic elements; will more often incorporate physical flows; and will be generally linked to a greater number of other models in organisations. Micros are making a substantial impact as tools for running decision support systems both of the corporate model and the ad hoc model variety. Forecasting techniques are still greatly underutilised in many organisations. Although most corporate models are currently of the deterministic financial simulation type, the influence of management education will help the adoption of more advanced models by more numerate senior managers and accountants. Indeed there is already evidence that this is happening in some organisations.     

Some debates and challenges in the literature on action learning: the state of the art since Revans

Action learning has travelled in some new directions and become an evolving practice since Revans first articulated his great idea. This paper focuses on some key challenges in the literature, some of which relate to these more recent directions in theory and practice. In particular, we consider the persistent problem of defining action learning and the varieties in practice which are in evidence, the nature of ‘action’ in action learning and the developing theory and practice of critical action learning as contrasted with the ‘classical’ approach to action learning. These debates are chosen for consideration here because they appear to strike at the heart of what action learning is for and because they are in evidence across a range of action learning literature. Some implications of these debates for human resource development (HRD) are also considered, including the potential action learning has for making a contribution to organizational learning, especially in treating ‘wicked’ problems and ill-structured challenges.     

考虑消费者网购体验滞后的产品定价研究

随着电子商务技术的发展，网络购物越来越便利。与此同时，网络购物带来的产品体验滞后也导致了消费者对产品的认知不确定性。而这种不确定性正在成为消费者策略性退货行为的主要原因，如消费者同时购买多件具有横向差异的产品，在收到货物后经亲身体验后保留一件而将其他产品退货。本文通过构建Hotelling模型，探讨了企业在考虑此种影响情况下的最优定价策略，分析得出：当消费者的退货成本增加时，企业最优定价也随之增加；消费者对产品的先验效用差异化越小，企业的最优定价也越低。同时发现，若某种产品无消费者单独购买，企业的最优定价会随消费者偏好的增加而增加；而当两种产品均有消费者单独购买且消费者退货成本较大时，企业的最优定价不但不会随消费者偏好的增加而提高，反而会随消费者偏好增加而减少。此外，本文给出了消费者策略性退货行为存在的临界条件，当消费者的退货成本高于这一临界条件时消费者的策略退货行为将消失。     

On the Development of Threshold Criteria for Action for Light Water Reactors

A survey of recently proposed threshold criteria for regulatory action on light water reactors (LWRs) is presented together with some commentary. This is followed by a new proposal for threshold action criteria which includes some different risk attributes than are found in previous criteria. Some preliminary risk values are suggested for the criteria and then evaluated in terms of a few hypothetical accident scenarios. Finally, several licensing issues are examined in terms of various threshold action criteria.     

Fall-Supervision in Gruppen und Teams: Mögliche Schwierigkeiten mit psychodramatischem Rollenspiel

Case oriented supervision in groups and teams: Potential Problems of Psychodramatic role-playingCase-oriented supervision is seen as promoting variety in perspectives upon cases. This relates to various levels (client-helper, team dynamics, institutional dynamics) and is a means of generating insights and new ways of working. Psychodramatic Role-playing is directed at broadening perspectives. Since it has become a widespread procedure in supervision some problems inherent in this are described. Psychodramatic role-playing is based upon group cohesion. Dramatic production itself leads by to ?prägnant“ solutions and gives a directive role to the supervisor. Hence the procedure can be inappropriate for groups in a timid or scapegoating phase. Furthermore it can be used to evade painful insights and the director can become the group leader. These problems are intensified in teams. Some proposals for dealing with these problems are presented. The question whether the illusion of feasibility is a general problem in supervision is broached.     

基于合作博弈的易腐性产品运输设施选择的费用分配

易腐性产品的价值会随着时间而损失,运输易腐性产品时,客户除了支付运输费用外还需要承担产品的价值损失。本文把易腐性产品的价值损失和运输费用之和作为总费用,应用合作博弈理论,把易腐性产品的运输设施选择的费用分配问题构造成费用分配博弈,证明了在易腐性产品线性价值损失的情况下,运输设施选择博弈的核心非空,且为子模博弈,并讨论核仁、夏普利值、τ-值等解。论文最后讨论了有约束运输的设施选择的费用分配博弈的解的情况,说明其核心也许为空,并提出了进一步研究的方向。