A structured groupware for a collective decision-making aid

We present the groupware MEMO-Net which aim is to support collective problem solving and to memorize all exchanged arguments. This groupware is based on a knowledge-structuring method (DIPA) that provides a work support for the team using the tool and that permits the exchanges' structure for a better knowledge management.     

A continuous approximation approach for the integrated facility-inventory allocation problem

In today’s retail business many companies have a complex distribution network with several national and regional distribution centers. This article studies an integrated facility location and inventory allocation problem for designing a distribution network with multiple distribution centers and retailers. The key decisions are where to locate the regional distribution centers (RDCs), how to assign retail stores to RDCs and what should be the inventory policy at the different locations such that the total network cost is minimized. Due to the complexity of the problem, a continuous approximation (CA) model is used to represent the network. Nonlinear programming techniques are developed to solve the optimization problems. The main contribution of this work lies in developing a new CA modeling technique when the discrete data cannot be modeled by a continuous function and applying this technique to solve an integrated facility location-allocation and inventory-management problem. Our methodology is illustrated with the network from a leading US retailer. Numerical analysis suggests that the total cost is significantly lower in the case of the integrated model as compared with the non-integrated model, where the location-allocation and inventory-management problems are considered separately. This paper also studies the effects of changing parameter values on the optimal solutions and to point out some management implications.     

Illumination: an affective experience?

What is the nature of illumination in mathematics? That is, what is it that sets illumination apart from other mathematical experiences? In this article the answer to this question is pursued through a qualitative study that seeks to compare and contrast the AHA! experiences of preservice teachers with those of prominent research mathematicians. Using a methodology of analytic induction in conjunction with historical and contemporary theories of discovery, creativity, and invention along with theories of affect the anecdotal reflections of participants from these two populations are analysed. Results indicate that, although manifested differently in the two populations, what sets illumination apart from other mathematical experiences are the affective aspects of the experience.     

Editorial

The credit crisis is a complex societal problem in which many phenomena and actors are involved. If one wants to analyze the causes of this problem, try to stabilize the situation and prevent new fall backs, a multi-disciplinary approach is prescribed. A careful analysis based on the scientific methodology of societal complexity is needed in order to find how the credit crisis happened and how new crises can be prevented. Theories of multiple disciplines must be used by a multi disciplinary team to analyze the situation and to find sustainable options. This process can be accomplished by following the Compram Methodology of DeTombe. The Compram Methodology provides a framework for policy making which includes many methods and tools. The Compram Methodology is specialized to handle complex interdisciplinary world-wide problems and to offer a step-by-step approach of analyzing the problem, finding and implementing sustainable interventions and evaluating the effects. The Compram Methodology offers a bird’s-eye view on the complexity of the problem and gives directions to policy makers to build their decisions on using a multi-disciplinary, multi-actor approach. In this article the credit crisis is discussed in relation with the Compram Methodology. Aspects of the credit crisis are described with an emphasis on the role of the actors. Based on the Compram Methodology directions can be provided for handling the credit crisis and avoiding future similar problems.     

Systemic problem structuring applied to community involvement in water conservation

Many advocates of problem structuring approaches mix methods to enhance the flexibility and responsiveness of OR practice. A number of ‘multi-methodology’ approaches have been developed to support practitioners in doing this, and one of these is systemic intervention. A distinguishing feature of systemic intervention is boundary critique: a theory and set of methodological ideas for exploring the inclusion, exclusion and marginalization of both people and issues. This paper argues that boundary critique can enhance the choice and process of application of problem structuring methods. An application of boundary critique is presented to illustrate the argument, focusing on community participation in the management of ongoing water shortages in a small seaside town in New Zealand. The theory of boundary critique helped to reframe people's understanding of a 30-year conflict between the District Council and community. This led to the design of a participative problem structuring workshop, and a way forward was identified that both the District Council and community could accept. Feedback from the workshop participants suggested that the intervention generated valuable results for all the parties involved. The paper concludes with some brief reflections on how the research agenda on boundary critique and problem structuring methods can be progressed into the future.     

Mathematical modelling at secondary school: the MACSI-Clongowes Wood College experience

In Ireland, to encourage the study of STEM (science, technology, engineering and mathematics) subjects and particularly mathematics, the Mathematics Applications Consortium for Science and Industry (MACSI) and Clongowes Wood College (County Kildare, Ireland) organized a mathematical modelling workshop for senior cycle secondary school students. Participants developed simple mathematical models for everyday life problems with an open-ended answer. The format and content of the workshop are described and feedback from both students and participating teachers is provided. For nearly all participants, this workshop was an enjoyable experience which showed mathematics and other STEM components in a very positive way.     

Planning for disaster: developing a multi-agency counselling service

Multi-agency planning is becoming increasingly important to organisations, especially those concerned with delivering services for the benefit of the community. This paper describes how a modified version of the methods from soft systems methodology (SSM), chosen through methodological reflections informed by critical systems thinking, was used to support the planning of a multi-agency counselling service that could be activated in the event of a disaster. Representatives of nineteen agencies were involved in this exercise, working together in six, one-day workshops. Feedback from participants, using four evaluation criteria (derived from the principles of SSM and the stated priorities of workshop participants), suggests that the methods of SSM, modified as described, show a great deal of promise as a support to multi-agency planning.     

Genetic algorithms for the bus driver scheduling problem: a case study

This paper describes an application of genetic algorithms to the bus driver scheduling problem. The application of genetic algorithms extends the traditional approach of Set Covering/Set Partitioning formulations, allowing the simultaneous consideration of several complex criteria. The genetic algorithm is integrated in a DSS but can be used as a very interactive tool or a stand-alone application. It incorporates the user's knowledge in a quite natural way and produces solutions that are almost directly implemented by the transport companies in their operational planning processes. Computational results with airline and bus crew scheduling problems from real world companies are presented and discussed.     

Subjective Aspects of the Art of Decision Analysis: Exploring the Role of Decision Analysis in Decision Structuring,Decision Support and Policy Dialogue

The paper argues that, until very recently, decision analysts have devoted relatively little attention to the processes of problem formulation and subjective judgement in handling ill-structured strategic decision problems. Therefore, following a brief review of existing varieties of decision analysis, a modified policy dialogue' model of decision analysis is presented which integrates decision analysis with decision aids and decision support technology. This model is developed using as an illustration strategic problems drawn from the insurance industry. The paper concludes with some suggestions for the successful application and implementation of decision analysis.     

我国跨境电商上市企业经营效率研究——基于三阶段DEA-Malmquist指数方法

以33家跨境电商上市企业为研究对象,基于三阶段DEA和Malmquist指数模型从静态和动态两个角度出发,对2013-2018年我国跨境电商上市企业的综合效率、全要素生产效率指数及两者的分解效率进行测度并对比分析,同时分析了宏观经济环境、政府干预和企业自身经营情况等因素对经营效率的影响.结果表明:样本企业经营效率存在个体差异,且外部环境对其经营效率具有显著影响;纯技术效率和规模效率参差不齐是导致综合技术效率分化严重的主要原因.基于此,跨境电商上市企业应积极配合政策变化,加强营销能力,及时调整经营规模,以防范宏观经济风险,提高企业经营效率.     

On the origins of OR and its institutions

Operational Research (OR) is the science of decision-making. From its military origins on the eve of World War II, OR has over the past seven decades matured to become a discipline that is recognised worldwide for its contributions to managerial planning and complex operations on all levels within both private companies and public institutions. Besides being an indispensable tool as a means for decision support, OR is today a well-established academic discipline and a field with its own institutions. Thus, OR-professionals are joined in national societies worldwide, assembled since 1959 in the global organization International Federation of OR Societies (IFORS) which again is subdivided into four Regional Groupings. Among those is the Association of European OR Societies (EURO) having as members the national societies of 31 countries notably in Europe. Two questions will be addressed: what is OR all about? How do National OR societies fit within the frameworks of IFORS and EURO? Partial answers are provided to both.     

Fictitious domain method with penalty for an incompressible fluid

Fictitious domain method shows great advantages when handling problems with complex and constantly varying domains. In this article, we propose an algorithm which extends the fictitious domain method by introducing penalties. Test results with the numerical examples of backward facing step problem and the flow around steady and dynamic cylinder problem show that the algorithm we propose is highly efficient for solving incompressible fluid problems. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010     

Optimal dynamic routing in Flexible Manufacturing Systems with limited buffers

An optimal routing policy is obtained for Flexible Manufacturing Systems (FMSs) with limited buffers at the work stations. This policy is used to effectively drive a robotic material handling system. The routing decisions are made by a supervising computer on a real-time basis in order to avoid any work station running out of inputs and to control the blocking of the material handling system. Using our model, general material handling times can be assumed. The optimal policy and several key performance measures are computed, following the problem formulation as a continuous-time, semi-Markovian decision process. Fast convergence and computational stability are ensured by the ergodic solution algorithm augmented to solve the functional equations of the renewal process. The solution algorithm was implemented, tested on an extensive range of problems regarding the structure and the performance of the optimal policy. Complex environments involving diverse processing times, as well as very limited buffer storage, were examined. The interaction between the allocation of buffer spaces to work stations, the structural properties of the optimal monotone (threshold-type) policy and the system performance are also investigated.     

Iterative algorithms for part grouping and loading in cellular reconfigurable manufacturing systems

A reconfigurable manufacturing system (RMS), one of state-of-the-art manufacturing system technologies, is the one designed at the outset for rapid changes in its hardware and software components in order to quickly adjust its production capacity and functionality in response to market or system changes. In this study, we consider a cellular RMS with multiple reconfigurable machining cells (RMCs), each of which has numerical control machines, a setup station, and an automatic material handling and storage system. Each machine within the RMC has an automatic tool changer and a tool magazine of a limited capacity. Two important operational problems, part grouping and loading, are considered in this study. Part grouping is the problem of allocating parts to RMCs, and loading is the problem of allocating operations and their cutting tools to machines within the RMC. An integer programming model is suggested to represent the two problems at the same time for the objective of balancing the workloads assigned to machines. Then, due to the complexity of the problem, we suggest two iterative algorithms in which the two problems are solved repeatedly until a solution is obtained. Computational experiments were done on various test instances and the results are reported.     

Improving long-run industrial decision making

The paper describes the present status of new product evaluation and decision making in large and small companies. It discusses the need to draw from a wide range of sources for societal as well as financial and technical information. While deficiencies and the need for improved analytical capabilities are identified, the emphasis is on what can be done, and near term problems using as an example the decision to produce a new type of vehicle engine.     

Methodology for participatory policy analysis

In the course of time it has become clear that policy analysts who use traditional formal modeling techniques have limited impact on policy making regarding complex policy problems. These kinds of problems require the analyst to combine scientific insights with subjective knowledge resources and to improve communication between the parties involved in the policy problem. A policy analyst who takes into account the need for social interaction has different participatory methods at his disposal, such as gaming/simulations, consensus conferences, and electronic meetings. Some assumptions with regard to the theoretical base, the application, and the effectiveness of participatory methods are formulated in this article. These assumptions can be tested and supplemented by means of comparative research on the effectiveness of participatory methods in different policy situations.     

Combined MCDA–IP Approach for Project Selection in the Electricity Market

The European policy target of substantially increasing the share of renewable energy in electricity generation, in combination with national subsidization support schemes, has strongly motivated private investors towards this business sector. In Greece, this interest is particularly apparent in the case of wind energy exploitation, due to a favourable legislative framework and the important wind potential available in several Greek regions. In such endowed regions, a very high number of applications were submitted to the competent authority, most of which compete for the same most attractive (windy) sites. The selection among these applications is a multicriteria problem that has been solved with the support of a Decision-Aid tool combining the multicriteria classification method ELECTRE-TRI with Integer Linear Programming. The developed approach takes into account both, the performances of the applications to the evaluation criteria, as well as a number of technical and policy constraints.     

Multicriteria energy policy investments and energy market clearance via integer programming

The deregulation of energy markets has created a framework for policy making, still under evolution, which is much more complex than the previous one. As a consequence, new requirements need to be met, concerning both technical design and financial management. This framework renders the use of multicriteria techniques attractive. Here, the investments in suppliers, depending on the policy implemented, are formulated as an integer programming problem, which consists of different sub-problems according to the assumptions made and the market’s regulations. The equivalent relaxed problem is a mixed integer programming problem that can represent the clearance of the energy market by considering several criteria besides price and quantity. Nonlinearities are reformulated by inserting additional binary variables so that the solution algorithms are more effective and efficient in most realistic cases. The feasible solutions and the optimal solution that maximizes every time the market regulator’s gain are obtained, after imposing some thresholds on the criteria used to evaluate the different energy technologies, thus creating a decision support system for the regulator.     

Reliable Numerical Computation in Civil Engineering

Civil engineering is a field – as are many other engineering sciences – where most of the methods used for solving optimization problems are based on experience and experiments, and models using local information, but drawn from global models. The present work outlines an interesting class of problems from this field, and initiates some possible ways to solve those problems utilizing the wide tool capabilities of interval arithmetic for error handling and interval branch-and-bound algorithms to solve the original or modified industrial models automating civil engineers' work. The investigations are in the first state but are promising both in a theoretical and in a practical sense.