3,857 research outputs found

    Decision support model for the selection of asphalt wearing courses in highly trafficked roads

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    The suitable choice of the materials forming the wearing course of highly trafficked roads is a delicate task because of their direct interaction with vehicles. Furthermore, modern roads must be planned according to sustainable development goals, which is complex because some of these might be in conflict. Under this premise, this paper develops a multi-criteria decision support model based on the analytic hierarchy process and the technique for order of preference by similarity to ideal solution to facilitate the selection of wearing courses in European countries. Variables were modelled using either fuzzy logic or Monte Carlo methods, depending on their nature. The views of a panel of experts on the problem were collected and processed using the generalized reduced gradient algorithm and a distance-based aggregation approach. The results showed a clear preponderance by stone mastic asphalt over the remaining alternatives in different scenarios evaluated through sensitivity analysis. The research leading to these results was framed in the European FP7 Project DURABROADS (No. 605404).The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under Grant Agreement No. 605404

    Analyzing the solutions of DEA through information visualization and data mining techniques: SmartDEA framework

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    Data envelopment analysis (DEA) has proven to be a useful tool for assessing efficiency or productivity of organizations, which is of vital practical importance in managerial decision making. DEA provides a significant amount of information from which analysts and managers derive insights and guidelines to promote their existing performances. Regarding to this fact, effective and methodologic analysis and interpretation of DEA solutions are very critical. The main objective of this study is then to develop a general decision support system (DSS) framework to analyze the solutions of basic DEA models. The paper formally shows how the solutions of DEA models should be structured so that these solutions can be examined and interpreted by analysts through information visualization and data mining techniques effectively. An innovative and convenient DEA solver, SmartDEA, is designed and developed in accordance with the proposed analysis framework. The developed software provides a DEA solution which is consistent with the framework and is ready-to-analyze with data mining tools, through a table-based structure. The developed framework is tested and applied in a real world project for benchmarking the vendors of a leading Turkish automotive company. The results show the effectiveness and the efficacy of the proposed framework

    Project portfolio evaluation and selection using mathematical programming and optimization methods

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    Project portfolio selection is an essential process for portfolio management and plays an important role in accomplishing organizational goals. This research explores the feasibility of developing a project portfolio selection tool by using mathematical programming and optimization models, specifically 0-1 integer programming (one objective portfolio) and goal programming (multiple objectives portfolio). These methods select the set of projects which deliver the maximum benefit (e.g., net present value, profit, etc.) represented for objective functions subjected to a series of constraints (e.g., technical requirements and/or resources availability) considering the scheduling of selected projects in a planning horizon, interdependence relationship among projects (e.g., complementary projects and mutually exclusive projects) and especial cases like mandatory and ongoing projects. ^ Based on the proposed model, a Decision Support System (DSS) will be developed and tested for accuracy, flexibility and ease of use. This computational tool will be designed for decision makers and users that are not familiar with mathematical programming models

    Weighted Goal Programming and Penalty Functions: Whole-farm Planning Approach Under Risk

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    The paper presents multiple criteria approach to deal with risk in farmer’s decisions. Decision making process is organised in a framework of spreadsheet tool. It is supported by deterministic and stochastic mathematical programming techniques applying optimisation concept. Decision making process is conceptually divided into seven autonomous modules that are mutually linked up. Beside the common maximisation of expected income through linear programming it enables also reconstruction of current production practice. Income risk modelling is based on portfolio theory resting on expected value, variance (E,V) paradigm. Modules dealing with risk are therefore supported with quadratic and constrained quadratic programming. Non-parametric approach is utilised to estimate decision maker’s risk attitude. It is measured with coefficient of risk aversion, needed to maximise certainty equivalent for analysed farms. Multiple criteria paradigm is based on goal programming approach. In contribution focus is put on benefits and possible drawbacks of supporting weighted goal programming with penalty functions. Application of the tool is illustrated with three dairy farm cases. Obtained results confirm advantage of utilizing penalty function system. Beside greater positiveness it proves as useful approach for fine tuning of the model enabling imitation of farmer’s behaviour, which is due to his/her conservative nature not perfect or rational. Results confirm hypothesis that single criteria decision making, based on maximisation of expected income, might be biased and does not necessary lead to the best - achievable option for analysed farm.goal programming, risk modelling, risk aversion, production planning, Risk and Uncertainty,

    AN INTERACTIVE PROCEDURE FOR AGGREGATE PRODUCTION PLANNING

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    Minimizing production cost over the planning period is usually assumed to be the objective of aggregate planning. However, other issues of strategic type may be even more important. Smoothing employment levels, driving down inventory levels or meeting high level of service usually are also considered. Thus, aggregate planning problem constitutes a multiple criteria decision making problem. In the paper a new approach for production aggregate planning problem is proposed. The procedure combines linear programming, simulation, and interactive approach. Linear programming models are used to generate initial solutions. In order to check how the fluctuations in demand will affect the results obtained under each of these solutions simulation experiments are performed. Finally, an interactive procedure is used for identifying the final solution of the problem

    AN INTERACTIVE PROCEDURE FOR AGGREGATE PRODUCTION PLANNING

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    Minimizing production cost over the planning period is usually assumed to be the objective of aggregate planning. However, other issues of strategic type may be even more important. Smoothing employment levels, driving down inventory levels or meeting high level of service usually are also considered. Thus, aggregate planning problem constitutes a multiple criteria decision making problem. In the paper a new approach for production aggregate planning problem is proposed. The procedure combines linear programming, simulation, and interactive approach. Linear programming models are used to generate initial solutions. In order to check how the fluctuations in demand will affect the results obtained under each of these solutions simulation experiments are performed. Finally, an interactive procedure is used for identifying the final solution of the problem

    A model based approach for complex dynamic decision-making

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    Current state-of-the-practice and state-of-the-art of decision-making aids are inadequate for modern organisations that deal with significant uncertainty and business dynamism. This paper highlights the limitations of prevalent decision-making aids and proposes a model-based approach that advances the modelling abstraction and analysis machinery for complex dynamic decision-making. In particular, this paper proposes a meta-model to comprehensively represent organisation, establishes the relevance of model-based simulation technique as analysis means, introduces the advancements over actor technology to address analysis needs, and proposes a method to utilise proposed modelling abstraction, analysis technique, and analysis machinery in an effective and convenient manner. The proposed approach is illustrated using a near real-life case-study from a business process outsourcing organisation

    Decision modelling tools for utilities in the deregulated energy market

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    This thesis examines the impact of the deregulation of the energy market on decision making and optimisation in utilities and demonstrates how decision support applications can solve specific encountered tasks in this context. The themes of the thesis are presented in different frameworks in order to clarify the complex decision making and optimisation environment where new sources of uncertainties arise due to the convergence of energy markets, globalisation of energy business and increasing competition. This thesis reflects the changes in the decision making and planning environment of European energy companies during the period from 1995 to 2004. It also follows the development of computational performance and evolution of energy information systems during the same period. Specifically, this thesis consists of studies at several levels of the decision making hierarchy ranging from top-level strategic decision problems to specific optimisation algorithms. On the other hand, the studies also follow the progress of the liberalised energy market from the monopolistic era to the fully competitive market with new trading instruments and issues like emissions trading. This thesis suggests that there is an increasing need for optimisation and multiple criteria decision making methods, and that new approaches based on the use of operations research are welcome as the deregulation proceeds and uncertainties increase. Technically, the optimisation applications presented are based on Lagrangian relaxation techniques and the dedicated Power Simplex algorithm supplemented with stochastic scenario analysis for decision support, a heuristic method to allocate common benefits and potential losses of coalitions of power companies, and an advanced Branch-and-Bound algorithm to solve efficiently non-convex optimisation problems. The optimisation problems are part of the operational and tactical decision making process that has become very complex in the recent years. Similarly, strategic decision support has also faced new challenges. This thesis introduces two applications involving multiple criteria decision making methods. The first application explores the decision making problem caused by the introduction of 'green' electricity that creates additional value for renewable energy. In this problem the stochastic multi-criteria acceptability analysis method (SMAA) is applied. The second strategic multi-criteria decision making study discusses two different energy-related operations research problems: the elements of risk analysis in the energy field and the evaluation of different choices with a decision support tool accommodating incomplete preference information to help energy companies to select a proper risk management system. The application is based on the rank inclusion in criteria hierarchies (RICH) method.reviewe
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