The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Erik Demeulemeester - One of the best experts on this subject based on the ideXlab platform.
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a model enhancement heuristic for building robust aircraft Maintenance Personnel rosters with stochastic constraints
European Journal of Operational Research, 2015Co-Authors: Philippe De Bruecker, Jeroen Belien, Jorne Van Den Bergh, Erik DemeulemeesterAbstract:This paper presents a heuristic approach to optimize staffing and scheduling at an aircraft Maintenance company. The goal is to build robust aircraft Maintenance Personnel rosters that can achieve a certain service level while minimizing the total labor costs. Robust Personnel rosters are rosters that can handle delays associated with stochastic flight arrival times. To deal with this stochasticity, a model enhancement algorithm is proposed that iteratively adjusts a mixed integer linear programming (MILP) model to a stochastic environment based on simulation results. We illustrate the performance of the algorithm with a computational experiment based on real life data of a large aircraft Maintenance company located at Brussels Airport in Belgium. The obtained results are compared to deterministic optimization and straightforward optimization. Experiments demonstrate that our model can ensure a certain desired service level with an acceptable increase in labor costs when stochasticity is introduced in the aircraft arrival times.
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a three stage approach for aircraft line Maintenance Personnel rostering using mip discrete event simulation and dea
Expert Systems With Applications, 2013Co-Authors: Jorne Van Den Bergh, Jeroen Belien, Philippe De Bruecker, Liesje De Boeck, Erik DemeulemeesterAbstract:Personnel scheduling problems need to cope with Personnel preferences, coverage constraints, legal restrictions, and many other constraints. We present a three-stage methodology that can be used to select Personnel rosters. In the first stage we generate multiple Personnel rosters with a mathematical programming model. In the second stage, the performance of the rosters regarding a number of service criteria is evaluated through discrete event simulation. In the third stage, a ranking is made using data envelopment analysis. The methodology is tested on a Personnel scheduling problem for aircraft line Maintenance.
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a tabu search heuristic for building aircraft Maintenance Personnel rosters
Social Science Research Network, 2012Co-Authors: Philippe De Bruecker, Jeroen Belien, Jorne Van Den Bergh, Erik DemeulemeesterAbstract:This paper presents a fast heuristic approach to optimize staffing and scheduling of the workforce at an aircraft Maintenance company. Two linked Tabu Search algorithms are proposed to minimize the labour costs and to maximize employee satisfaction. To enhance the performance of the algorithm, strategic oscillation and pattern creation are used. We illustrate the performance of the algorithms with a computational experiment based on real life data from Sabena Technics, a large aircraft Maintenance company located at Brussels Airport in Belgium. We analyze the results in different scenarios and compare them to a mixed integer linear programming model. The experiments demonstrate that Tabu Search can deliver acceptable solutions faster than the integer programming technique for small instances and outperforms the integer programming model for larger and more realistic problem sizes.
J M Godoy - One of the best experts on this subject based on the ideXlab platform.
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radioactivity concentration in liquid and solid phases of scale and sludge generated in the petroleum industry
Journal of Environmental Radioactivity, 2005Co-Authors: Maria Helena Paranhos Gazineu, Andressa Arruda De Araujo, Yana Batista Brandao, Clovis A Hazin, J M GodoyAbstract:Abstract Scales and sludge generated during oil extraction and production can contain uranium, thorium, radium and other natural radionuclides, which can cause exposure of Maintenance Personnel. This work shows how the oil content can influence the results of measurements of radionuclide concentration in scale and sludge. Samples were taken from a PETROBRAS unit in Northeast Brazil. They were collected directly from the inner surface of water pipes or from barrels stored in the waste storage area of the E&P unit. The oil was separated from the solids with a Soxhlet extractor by using aguarras at 90 ± 5°C as solvent. Concentrations of 226 Ra and 228 Ra in the samples were determined before and after oil extraction by using an HPGe gamma spectrometric system. The results showed an increase in the radionuclide concentration in the solid (dry) phase, indicating that the above radionuclides concentrate mostly in the solid material.
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radioactivity concentration in liquid and solid phases of scale and sludge generated in the petroleum industry
Journal of Environmental Radioactivity, 2005Co-Authors: Maria Helena Paranhos Gazineu, Andressa Arruda De Araujo, Yana Batista Brandao, Clovis A Hazin, J M GodoyAbstract:Scales and sludge generated during oil extraction and production can contain uranium, thorium, radium and other natural radionuclides, which can cause exposure of Maintenance Personnel. This work shows how the oil content can influence the results of measurements of radionuclide concentration in scale and sludge. Samples were taken from a PETROBRAS unit in Northeast Brazil. They were collected directly from the inner surface of water pipes or from barrels stored in the waste storage area of the E&P unit. The oil was separated from the solids with a Soxhlet extractor by using aguarras at 90+/-5 degrees C as solvent. Concentrations of 226Ra and 228Ra in the samples were determined before and after oil extraction by using an HPGe gamma spectrometric system. The results showed an increase in the radionuclide concentration in the solid (dry) phase, indicating that the above radionuclides concentrate mostly in the solid material.
Philippe De Bruecker - One of the best experts on this subject based on the ideXlab platform.
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a model enhancement heuristic for building robust aircraft Maintenance Personnel rosters with stochastic constraints
European Journal of Operational Research, 2015Co-Authors: Philippe De Bruecker, Jeroen Belien, Jorne Van Den Bergh, Erik DemeulemeesterAbstract:This paper presents a heuristic approach to optimize staffing and scheduling at an aircraft Maintenance company. The goal is to build robust aircraft Maintenance Personnel rosters that can achieve a certain service level while minimizing the total labor costs. Robust Personnel rosters are rosters that can handle delays associated with stochastic flight arrival times. To deal with this stochasticity, a model enhancement algorithm is proposed that iteratively adjusts a mixed integer linear programming (MILP) model to a stochastic environment based on simulation results. We illustrate the performance of the algorithm with a computational experiment based on real life data of a large aircraft Maintenance company located at Brussels Airport in Belgium. The obtained results are compared to deterministic optimization and straightforward optimization. Experiments demonstrate that our model can ensure a certain desired service level with an acceptable increase in labor costs when stochasticity is introduced in the aircraft arrival times.
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a three stage approach for aircraft line Maintenance Personnel rostering using mip discrete event simulation and dea
Expert Systems With Applications, 2013Co-Authors: Jorne Van Den Bergh, Jeroen Belien, Philippe De Bruecker, Liesje De Boeck, Erik DemeulemeesterAbstract:Personnel scheduling problems need to cope with Personnel preferences, coverage constraints, legal restrictions, and many other constraints. We present a three-stage methodology that can be used to select Personnel rosters. In the first stage we generate multiple Personnel rosters with a mathematical programming model. In the second stage, the performance of the rosters regarding a number of service criteria is evaluated through discrete event simulation. In the third stage, a ranking is made using data envelopment analysis. The methodology is tested on a Personnel scheduling problem for aircraft line Maintenance.
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a tabu search heuristic for building aircraft Maintenance Personnel rosters
Social Science Research Network, 2012Co-Authors: Philippe De Bruecker, Jeroen Belien, Jorne Van Den Bergh, Erik DemeulemeesterAbstract:This paper presents a fast heuristic approach to optimize staffing and scheduling of the workforce at an aircraft Maintenance company. Two linked Tabu Search algorithms are proposed to minimize the labour costs and to maximize employee satisfaction. To enhance the performance of the algorithm, strategic oscillation and pattern creation are used. We illustrate the performance of the algorithms with a computational experiment based on real life data from Sabena Technics, a large aircraft Maintenance company located at Brussels Airport in Belgium. We analyze the results in different scenarios and compare them to a mixed integer linear programming model. The experiments demonstrate that Tabu Search can deliver acceptable solutions faster than the integer programming technique for small instances and outperforms the integer programming model for larger and more realistic problem sizes.
Jorne Van Den Bergh - One of the best experts on this subject based on the ideXlab platform.
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a model enhancement heuristic for building robust aircraft Maintenance Personnel rosters with stochastic constraints
European Journal of Operational Research, 2015Co-Authors: Philippe De Bruecker, Jeroen Belien, Jorne Van Den Bergh, Erik DemeulemeesterAbstract:This paper presents a heuristic approach to optimize staffing and scheduling at an aircraft Maintenance company. The goal is to build robust aircraft Maintenance Personnel rosters that can achieve a certain service level while minimizing the total labor costs. Robust Personnel rosters are rosters that can handle delays associated with stochastic flight arrival times. To deal with this stochasticity, a model enhancement algorithm is proposed that iteratively adjusts a mixed integer linear programming (MILP) model to a stochastic environment based on simulation results. We illustrate the performance of the algorithm with a computational experiment based on real life data of a large aircraft Maintenance company located at Brussels Airport in Belgium. The obtained results are compared to deterministic optimization and straightforward optimization. Experiments demonstrate that our model can ensure a certain desired service level with an acceptable increase in labor costs when stochasticity is introduced in the aircraft arrival times.
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a three stage approach for aircraft line Maintenance Personnel rostering using mip discrete event simulation and dea
Expert Systems With Applications, 2013Co-Authors: Jorne Van Den Bergh, Jeroen Belien, Philippe De Bruecker, Liesje De Boeck, Erik DemeulemeesterAbstract:Personnel scheduling problems need to cope with Personnel preferences, coverage constraints, legal restrictions, and many other constraints. We present a three-stage methodology that can be used to select Personnel rosters. In the first stage we generate multiple Personnel rosters with a mathematical programming model. In the second stage, the performance of the rosters regarding a number of service criteria is evaluated through discrete event simulation. In the third stage, a ranking is made using data envelopment analysis. The methodology is tested on a Personnel scheduling problem for aircraft line Maintenance.
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a tabu search heuristic for building aircraft Maintenance Personnel rosters
Social Science Research Network, 2012Co-Authors: Philippe De Bruecker, Jeroen Belien, Jorne Van Den Bergh, Erik DemeulemeesterAbstract:This paper presents a fast heuristic approach to optimize staffing and scheduling of the workforce at an aircraft Maintenance company. Two linked Tabu Search algorithms are proposed to minimize the labour costs and to maximize employee satisfaction. To enhance the performance of the algorithm, strategic oscillation and pattern creation are used. We illustrate the performance of the algorithms with a computational experiment based on real life data from Sabena Technics, a large aircraft Maintenance company located at Brussels Airport in Belgium. We analyze the results in different scenarios and compare them to a mixed integer linear programming model. The experiments demonstrate that Tabu Search can deliver acceptable solutions faster than the integer programming technique for small instances and outperforms the integer programming model for larger and more realistic problem sizes.
Maria Helena Paranhos Gazineu - One of the best experts on this subject based on the ideXlab platform.
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radioactivity concentration in liquid and solid phases of scale and sludge generated in the petroleum industry
Journal of Environmental Radioactivity, 2005Co-Authors: Maria Helena Paranhos Gazineu, Andressa Arruda De Araujo, Yana Batista Brandao, Clovis A Hazin, J M GodoyAbstract:Abstract Scales and sludge generated during oil extraction and production can contain uranium, thorium, radium and other natural radionuclides, which can cause exposure of Maintenance Personnel. This work shows how the oil content can influence the results of measurements of radionuclide concentration in scale and sludge. Samples were taken from a PETROBRAS unit in Northeast Brazil. They were collected directly from the inner surface of water pipes or from barrels stored in the waste storage area of the E&P unit. The oil was separated from the solids with a Soxhlet extractor by using aguarras at 90 ± 5°C as solvent. Concentrations of 226 Ra and 228 Ra in the samples were determined before and after oil extraction by using an HPGe gamma spectrometric system. The results showed an increase in the radionuclide concentration in the solid (dry) phase, indicating that the above radionuclides concentrate mostly in the solid material.
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radioactivity concentration in liquid and solid phases of scale and sludge generated in the petroleum industry
Journal of Environmental Radioactivity, 2005Co-Authors: Maria Helena Paranhos Gazineu, Andressa Arruda De Araujo, Yana Batista Brandao, Clovis A Hazin, J M GodoyAbstract:Scales and sludge generated during oil extraction and production can contain uranium, thorium, radium and other natural radionuclides, which can cause exposure of Maintenance Personnel. This work shows how the oil content can influence the results of measurements of radionuclide concentration in scale and sludge. Samples were taken from a PETROBRAS unit in Northeast Brazil. They were collected directly from the inner surface of water pipes or from barrels stored in the waste storage area of the E&P unit. The oil was separated from the solids with a Soxhlet extractor by using aguarras at 90+/-5 degrees C as solvent. Concentrations of 226Ra and 228Ra in the samples were determined before and after oil extraction by using an HPGe gamma spectrometric system. The results showed an increase in the radionuclide concentration in the solid (dry) phase, indicating that the above radionuclides concentrate mostly in the solid material.
