CEGI - Book Chapters

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    An agent-based approach to schedule crane operations in rail-rail transshipment terminals
    ( 2016) Sam Heshmati ; Kokkinogenis,Z ; Rossetti,RJF ; Maria Antónia Carravilla ; José Fernando Oliveira
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    Constraint aggregation in non-linear programming models for nesting problems
    ( 2016) Pedro Filipe Rocha ; Gomes,AM ; Rui Pedro Rodrigues ; Toledo,FMB ; Andretta,M
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    The cutting stock problem: A case study in a manufacturer of pet vivaria
    ( 2015) Sousa,C ; Elsa Marília Silva ; Lopes,M ; António Galrão Ramos
    This paper addresses the problem of determining the cutting patterns of metal sheets, which arises in a manufacturer of metal cages, in order to minimize the waste, the number of cuts performed, the number of metal sheets used or a weighted combination of the three. A two stage approach, to solve a 2D guillotine cutting stock problem with single and multiple stock sizes, is presented and compared with the company approach and state-of-the-art algorithms. The results show great improvement compared to the company approach and a very good performance compared to state-of-the-art algorithms.
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    Demand uncertainty for the location-routing problem with two-dimensional loading constraints
    ( 2016) de Queiroz,TA ; José Fernando Oliveira ; Maria Antónia Carravilla ; Miyazawa,FK
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    Design of retail backroom storage: A research opportunity?
    ( 2015) Maria João Pires ; Pedro Amorim ; Liz,J ; Pratas,J
    The design of retail backroom storage has a great impact on in-store operations, customer service levels and store life-cycle costs. Moreover, backroom storage in modern retail stores is crucial to several functions, such as acting as a buffer against strong demand lifts yielded by an increasing promotional activity, seasonal peak demand and e-commerce activities. Despite having similar functions to a distribution center, backroom storage facilities have particularities that deserve a distinct analysis. In this paper we aim to draw attention to the lack of research about this topic.
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    Eco-efficiency assessment at firm level: An application to the mining sector
    ( 2015) Renata Melo Oliveira ; Ana Camanho ; Andreia Zanella
    Assessing firms' Eco-efficiency is important to ensure they succeed in creating wealth without compromising the needs of future generations. This work aims to extend the Eco-efficiency concept by including in the assessment new features related to environmental benefits. Eco-efficiency is evaluated using a DEA model specified with a Directional Distance Function. The new methodology proposed in this paper is illustrated with an application to world-class mining companies, whose results and managerial implications are discussed.
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    A GRASP algorithm for the vehicle-reservation assignment problem
    ( 2016) Beatriz Brito Oliveira ; Maria Antónia Carravilla ; José Fernando Oliveira
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    Improving the robustness of bus schedules using an optimization model
    ( 2015) Hora,J ; Teresa Galvão ; Ana Camanho
    This study pursues the operational improvement of urban transportation services. Non-foreseen events lead to the occurrence of delays, which are further propagated during the daily operations of bus services. This paper applies an optimization model to obtain robust schedules of bus lines. The model builds a new schedule which minimizes delays and anticipations from a set of observations. The decision variables are the slack time to be allocated at each segment of two subsequent stops. The solutions obtained are assessed with two robustness measures: price of robustness (i.e. the deviations from schedule) and the percentage of absorbed delays. The results obtained in a real-world case study (a bus line operating in Porto) are promising.
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    Integrated cutting and production planning: A case study in a home textile manufacturing company
    ( 2015) Elsa Marília Silva ; Viães,C ; José Fernando Oliveira ; Maria Antónia Carravilla
    In this paper we consider the problem of minimizing the waste of textile material in a Portuguese home textile manufacturing company. The company has a vertical structure covering the different production stages of the home textile, from weaving until the finished products. Production planning comprises different decisions: the definition of the widths and lengths of the fabric rolls to be produced, the number of fabric rolls to be used from stock or purchased and the definition of the cutting patterns to be applied to each width of the fabric roll, so that the waste is minimized. We propose a MIP model, solved by a column generation method, to tackle the problem.
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    A MIP model for production planning in the roasting coffee industry
    ( 2016) Ospina,DY ; Maria Antónia Carravilla ; José Fernando Oliveira
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    Modeling lot sizing and scheduling in practice
    ( 2015) Luís Guimarães ; Gonçalo Reis Figueira ; Pedro Amorim ; Bernardo Almada-Lobo
    Lot sizing and scheduling by mixed integer programming has been a hot research topic in the last 20 years. Researchers have been trying to develop stronger formulations, as well as to incorporate real-world requirements from different applications. In this paper we illustrate some of these requirements and show howmodels have been adapted and extended. Motivation comes from different industries, especially from process and fast moving consumer goods industries.
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    Modelo de apoio à gestão da pescaria de bivalves com ganchorra no Algarve baseado em dinâmica de sistemas
    ( 2014) Ana Camanho ; Joana Maria Hora ; Manuela Maria Oliveira ; Gaspar,MB
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    An operating theater planning decision support system
    ( 2013) Gomes,C ; Sperandio,F ; Peles,A ; José Luís Borges ; António Carvalho Brito ; Bernardo Almada-Lobo
    The operating theater is the biggest hospital budget expenditure. The usage of surgery related resources and its intrinsic planning must be carefully devised in order to achieve better operational performance. However, from long to short term planning, the decision processes inherent to the operating theater are often the subject of empiricism. Moreover, the current hospital information systems available in Portuguese public hospitals lack a decision support system component, which could assist in achieving better planning solutions. This work reports the development of a centralized system for the operating theater planning to support decision-making tasks of surgeons, chief specialty managers, and hospital administration. Its main components concern surgery scheduling, operating theater's resource allocation and performance measurement. The enhancement of the planning processes, the increase of policy compliance, and the overall performance of the operating theater compared to the former methodologies are also discussed. © 2013, IGI Global.
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    Pricing for internet sales channels in car rentals
    ( 2015) Beatriz Brito Oliveira ; Maria Antónia Carravilla ; José Fernando Oliveira ; Raicar,P ; Acácio,D ; Ferreira,J ; Araújo,P
    Internet sales channels, especially e-brokers that compare prices in the market, have a major impact on car rentals. As costs are heavily correlated with unoccupied fleet, occupation considerations should be integrated with swift responses to the market prices. This work was developed alongside Guerin, a Portuguese car rental, to build a tool that quickly updates prices on e-brokers websites to increase total value. This paper describes the specificities of the problem and their implication on the solution, and presents an adaptative heuristic to update prices and the system's architecture.
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    Reliability metrics for the evaluation of the schedule plan in public transportation
    ( 2015) Jorge Freire Sousa ; Mendes-Moreira,J ; Moreira-Matias,L ; Gama,J
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    Tree Search and Simulation
    ( 2015) João Pedro Pedroso ; Rei,R