4,699 research outputs found

    Design and Control of Warehouse Order Picking: a literature review

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    Order picking has long been identified as the most labour-intensive and costly activity for almost every warehouse; the cost of order picking is estimated to be as much as 55% of the total warehouse operating expense. Any underperformance in order picking can lead to unsatisfactory service and high operational cost for its warehouse, and consequently for the whole supply chain. In order to operate efficiently, the orderpicking process needs to be robustly designed and optimally controlled. This paper gives a literature overview on typical decision problems in design and control of manual order-picking processes. We focus on optimal (internal) layout design, storage assignment methods, routing methods, order batching and zoning. The research in this area has grown rapidly recently. Still, combinations of the above areas have hardly been explored. Order-picking system developments in practice lead to promising new research directions.Order picking;Logistics;Warehouse Management

    A Genetic Algorithm solver for pest management control in Island systems

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    Island conservation management is a truly multidisciplinary problem that requires considerable knowledge of the characteristics of the ecosystem, species and their interactions. Nevertheless, this can be translated into an optimisation problem. Essentially, within a limited budget, a manager needs to select the conservation actions according to expected payoffs (in terms of protecting or restoring desired species) versus cost (the amount of resources/money) required for the actions. This paper presents the problem in terms of a knapsack formulation and develops optimisation techniques to solve it. From this, decision-support software is being developed, tailored to meet the needs of pest control on islands for conservation managers. The solver uses a Genetic Algorithm and incorporates a simplified model of the problem. The solver derives strategies that reduce the number of threats, allowing the preservation of desired species. However, the problem model needs further refinement to derive truly realistic options for conservation managers

    Integrated design : a generative multi-performative design approach

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.MIT Institute Archives copy: with CD-ROM; divisional library copy with no CD-ROM.Includes bibliographical references (leaves 70-72).There are building systems, called "modularized", in which the component systems (for structure, lighting, etc) can be analyzed and synthesized independently since their performance and design do not interact or affect one another. There are other building systems, called "coupled", in which the component systems do interact and influence one another. The thesis acknowledges that in a building there are both sub-systems that act independently and others that interact. While many design processes have been proposed for dealing with discrete sub-systems, there is no systematic study for building sub-systems that interrelate. This thesis examines a different design approach called integrated. The term "integrated" has a dual utilization in this study. The first use refers to the integration of form and building performance. The second use refers to the integration of interrelated and diverse building performances involving multiple disciplines. The integrated design approach analyzes and evaluates several interrelated design systems involving different disciplines in the early design phase. The goal of the approach is the generation of design alternatives guided simultaneously by two basic objectives: the aspiration for form exploration and the satisfaction of the performances of interrelated systems. After defining a framework for an integrated design approach, which includes inter-disciplinary collaboration, unified design, optimization, simulation, and other formal and digital techniques, the approach will be demonstrated in a case study. The objective of the case study is to demonstrate that the integrated design approach has validity and can be realized, in this case, for the generation of high-rise buildings guided by structural, lighting, zoning codes, and aesthetic criteria.by Eleftheria Fasoulaki.S.M

    Using response surface design to determine the optimal parameters of genetic algorithm and a case study

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    Copyright © 2013 Taylor & Francis. This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Production Research on 09 June 2013, available online: http://www.tandfonline.com/10.1080/00207543.2013.784411Genetic algorithms are efficient stochastic search techniques for approximating optimal solutions within complex search spaces and used widely to solve NP hard problems. This algorithm includes a number of parameters whose different levels affect the performance of the algorithm strictly. The general approach to determine the appropriate parameter combination of genetic algorithm depends on too many trials of different combinations and the best one of the combinations that produces good results is selected for the program that would be used for problem solving. A few researchers studied on parameter optimisation of genetic algorithm. In this paper, response surface depended parameter optimisation is proposed to determine the optimal parameters of genetic algorithm. Results are tested for benchmark problems that is most common in mixed-model assembly line balancing problems of type-I (MMALBP-I)

    Supervised regionalization methods, a survey.

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    This paper reviews almost four decades of contributions on the subject of supervised regionalization methods. These methods aggregate a set of areas into a predefined number of spatially contiguous regions while optimizing certain aggregation criteria. The authors present a taxonomic scheme that classifies a wide range of regionalization methods into eight groups, based on the strategy applied for satisfying the spatial contiguity constraint. The paper concludes by providing a qualitative comparison of these groups in terms of a set of certain characteristics, and by suggesting future lines of research for extending and improving these methods.regionalization, constrained clustering, analytical regions.

    Research Trends and Outlooks in Assembly Line Balancing Problems

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    This paper presents the findings from the survey of articles published on the assembly line balancing problems (ALBPs) during 2014-2018. Before proceeding a comprehensive literature review, the ineffectiveness of the previous ALBP classification structures is discussed and a new classification scheme based on the layout configurations of assembly lines is subsequently proposed. The research trend in each layout of assembly lines is highlighted through the graphical presentations. The challenges in the ALBPs are also pinpointed as a technical guideline for future research works
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