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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Programação de tripulantes de aeronaves no contexto brasileiro. / Airline crew scheduling in the Brazilian context.

Gomes, Wagner de Paula 05 October 2009 (has links)
Esta pesquisa trata o Problema de Programação de Tripulantes (PPT), presente no planejamento operacional das empresas aéreas. O principal objetivo do PPT é atribuir um conjunto de tarefas aos tripulantes, considerando as regulamentações trabalhistas, as regras de segurança e as políticas das empresas, de tal maneira que o custo da tripulação seja mínimo. O PPT é normalmente dividido em dois subproblemas, resolvidos sequencialmente: Problema de Determinação das Viagens (PDV) e Problema de Atribuição de Escalas (PAE). No PDV, determina-se um conjunto de viagens que cubra todos os voos planejados. Em seguida, no PAE, as escalas, compostas pelas viagens escolhidas e outras atividades como folgas, sobreavisos, reservas, treinamentos e férias, são atribuídas aos tripulantes. Esta decomposição justifica-se pela natureza combinatória do PPT, porém não incorpora as disponibilidades e as preferências dos tripulantes em ambos os subproblemas (PDV e PAE), gerando assim custos extras relacionados aos conflitos que surgem durante a atribuição das escalas aos tripulantes no PAE. Além disso, as estimativas de custos adotadas no PDV não possuem caráter global, já que o custo real da programação só pode ser obtido após a atribuição das escalas. O estado da arte envolve a solução integrada do PPT, em que se elimina a necessidade de resolver inicialmente o PDV, provendo assim uma melhor estimativa de custo e uma programação final com melhor qualidade, por considerar os custos da tripulação, as disponibilidades e preferências dos tripulantes de forma global. O problema, no entanto, é NP-Difícil. Assim sendo, a metodologia proposta nesta pesquisa objetiva a solução do PPT de forma integrada, através de um Algoritmo Genético Híbrido (AGH) associado a um procedimento de busca em profundidade, levando em conta as particularidades da legislação brasileira. A metodologia foi testada, com sucesso, para a solução de instâncias baseadas na malha real de uma empresa aérea brasileira. / This master of science research treats the Crew Scheduling Problem (CSP), as part of the airlines operational planning. The main aim of the CSP is to assign a set of tasks to crew members, considering the labor regulations, safety rules and policies of companies, such that the crew cost is minimal. The CSP is divided into two subproblems, solved sequentially: Crew Pairing Problem (CPP) and Crew Rostering Problem (CRP). First, CPP provides a set of pairings that covers all the planned flights. Then, in the CRP, the rosters, encompassing the pairings and other activities such as rest periods, alert duties, reserve duties, training times and vacations, are assigned to the crew members. This decomposition is justified by the combinatorial nature of the CSP, but it not incorporates the crew members availabilities and preferences in both subproblems (CPP and CRP), generating extra costs related to conflicts that arise during the assignment of rosters to the crew members in the CRP. Besides, the costs estimations adopted in the CPP does not have a global character, since the real cost of the global schedule can be only obtained after the assignment of the rosters. The state of the art involves the integrated solution of CSP, where the CPP does not need to be solved, thus providing a better estimated cost and a better schedule quality, considering crew costs and also crew members availabilities and preferences globally. The problem, however, is NP-Hard. Therefore, the methodology proposed in this master of science research aims to obtain an integrated solution of the CSP, through an hybrid algorithm genetic associated with a depth-first search procedure, taking into account the Brazilian legislation. The methodology was tested, with success, to solve instances related a real network of a Brazilian airline.
2

Programação de tripulantes de aeronaves no contexto brasileiro. / Airline crew scheduling in the Brazilian context.

Wagner de Paula Gomes 05 October 2009 (has links)
Esta pesquisa trata o Problema de Programação de Tripulantes (PPT), presente no planejamento operacional das empresas aéreas. O principal objetivo do PPT é atribuir um conjunto de tarefas aos tripulantes, considerando as regulamentações trabalhistas, as regras de segurança e as políticas das empresas, de tal maneira que o custo da tripulação seja mínimo. O PPT é normalmente dividido em dois subproblemas, resolvidos sequencialmente: Problema de Determinação das Viagens (PDV) e Problema de Atribuição de Escalas (PAE). No PDV, determina-se um conjunto de viagens que cubra todos os voos planejados. Em seguida, no PAE, as escalas, compostas pelas viagens escolhidas e outras atividades como folgas, sobreavisos, reservas, treinamentos e férias, são atribuídas aos tripulantes. Esta decomposição justifica-se pela natureza combinatória do PPT, porém não incorpora as disponibilidades e as preferências dos tripulantes em ambos os subproblemas (PDV e PAE), gerando assim custos extras relacionados aos conflitos que surgem durante a atribuição das escalas aos tripulantes no PAE. Além disso, as estimativas de custos adotadas no PDV não possuem caráter global, já que o custo real da programação só pode ser obtido após a atribuição das escalas. O estado da arte envolve a solução integrada do PPT, em que se elimina a necessidade de resolver inicialmente o PDV, provendo assim uma melhor estimativa de custo e uma programação final com melhor qualidade, por considerar os custos da tripulação, as disponibilidades e preferências dos tripulantes de forma global. O problema, no entanto, é NP-Difícil. Assim sendo, a metodologia proposta nesta pesquisa objetiva a solução do PPT de forma integrada, através de um Algoritmo Genético Híbrido (AGH) associado a um procedimento de busca em profundidade, levando em conta as particularidades da legislação brasileira. A metodologia foi testada, com sucesso, para a solução de instâncias baseadas na malha real de uma empresa aérea brasileira. / This master of science research treats the Crew Scheduling Problem (CSP), as part of the airlines operational planning. The main aim of the CSP is to assign a set of tasks to crew members, considering the labor regulations, safety rules and policies of companies, such that the crew cost is minimal. The CSP is divided into two subproblems, solved sequentially: Crew Pairing Problem (CPP) and Crew Rostering Problem (CRP). First, CPP provides a set of pairings that covers all the planned flights. Then, in the CRP, the rosters, encompassing the pairings and other activities such as rest periods, alert duties, reserve duties, training times and vacations, are assigned to the crew members. This decomposition is justified by the combinatorial nature of the CSP, but it not incorporates the crew members availabilities and preferences in both subproblems (CPP and CRP), generating extra costs related to conflicts that arise during the assignment of rosters to the crew members in the CRP. Besides, the costs estimations adopted in the CPP does not have a global character, since the real cost of the global schedule can be only obtained after the assignment of the rosters. The state of the art involves the integrated solution of CSP, where the CPP does not need to be solved, thus providing a better estimated cost and a better schedule quality, considering crew costs and also crew members availabilities and preferences globally. The problem, however, is NP-Hard. Therefore, the methodology proposed in this master of science research aims to obtain an integrated solution of the CSP, through an hybrid algorithm genetic associated with a depth-first search procedure, taking into account the Brazilian legislation. The methodology was tested, with success, to solve instances related a real network of a Brazilian airline.
3

Modelagem integrada do problema de programação de tripulantes de aeronaves. / Integrated modeling of the airline crew scheduling problem.

Gomes, Wagner de Paula 20 January 2014 (has links)
Esta pesquisa trata o Problema de Programação de Tripulantes (PPT), presente no planejamento operacional das empresas aéreas. O principal objetivo do PPT é atribuir o conjunto de tripulantes requeridos para a operação dos voos de uma malha aérea de maneira a minimizar o custo total da tripulação, levando em conta a legislação pertinente e a satisfação dos tripulantes. O PPT é normalmente dividido na literatura em dois subproblemas independentes, modelados e resolvidos sequencialmente: Problema de Determinação de Viagens (PDV) e Problema de Atribuição de Escalas (PAE). Esta decomposição não incorpora os atributos (disponibilidade, qualificação, senioridade e preferências individuais) dos tripulantes de forma global, o que não permite uma estimativa real de custo e afeta a qualidade da solução final. O estado da arte envolve a solução integrada do PPT, eliminando a necessidade de se resolver inicialmente o PDV e permitindo a obtenção de uma solução mais realista. O PPT, no entanto, é de natureza combinatória. Assim sendo, esta pesquisa propõe e explora modelos baseados em programação linear inteira e em heurísticas para a solução integrada do PPT. Essas heurísticas incorporam fundamentos da meta-heurística GRASP, da heurística de economias de Clarke e Wright e da heurística day-by-day. Os modelos foram testados com sucesso para a solução de instâncias baseadas na malha real de três empresas aéreas brasileiras. / This doctoral research treats the Crew Scheduling Problem (CSP), as part of the airlines operational planning. The CSP consists of optimally assigning the required crew members to planned flights, in such a way that it minimizes the total cost of the aircrew, taking into consideration the proper legislation and the satisfaction of the crew members. The CSP is usually divided into two independent subproblems, modeled and solved sequentially: Crew Pairing Problem (CPP) and Crew Rostering Problem (CRP). This decomposition does not incorporate all the crew members attributes (availability, qualification, seniority and individual preferences), which does not lead to a real cost estimate and affects the quality of the final solution. The state of the art involves the integrated solution of CSP, without solving the CPP at first and providing a more realistic solution. The CSP, however, has a combinatorial nature. This research proposes and explores models based on integer linear programming and on heuristics to solve the CSP in an integrated way. These heuristics incorporate GRASP metaheuristic, Clarke and Wright savings heuristic and day-by-day heuristic. The models were successfully tested to solve instances related to the networks of three Brazilian airlines.
4

Modelagem integrada do problema de programação de tripulantes de aeronaves. / Integrated modeling of the airline crew scheduling problem.

Wagner de Paula Gomes 20 January 2014 (has links)
Esta pesquisa trata o Problema de Programação de Tripulantes (PPT), presente no planejamento operacional das empresas aéreas. O principal objetivo do PPT é atribuir o conjunto de tripulantes requeridos para a operação dos voos de uma malha aérea de maneira a minimizar o custo total da tripulação, levando em conta a legislação pertinente e a satisfação dos tripulantes. O PPT é normalmente dividido na literatura em dois subproblemas independentes, modelados e resolvidos sequencialmente: Problema de Determinação de Viagens (PDV) e Problema de Atribuição de Escalas (PAE). Esta decomposição não incorpora os atributos (disponibilidade, qualificação, senioridade e preferências individuais) dos tripulantes de forma global, o que não permite uma estimativa real de custo e afeta a qualidade da solução final. O estado da arte envolve a solução integrada do PPT, eliminando a necessidade de se resolver inicialmente o PDV e permitindo a obtenção de uma solução mais realista. O PPT, no entanto, é de natureza combinatória. Assim sendo, esta pesquisa propõe e explora modelos baseados em programação linear inteira e em heurísticas para a solução integrada do PPT. Essas heurísticas incorporam fundamentos da meta-heurística GRASP, da heurística de economias de Clarke e Wright e da heurística day-by-day. Os modelos foram testados com sucesso para a solução de instâncias baseadas na malha real de três empresas aéreas brasileiras. / This doctoral research treats the Crew Scheduling Problem (CSP), as part of the airlines operational planning. The CSP consists of optimally assigning the required crew members to planned flights, in such a way that it minimizes the total cost of the aircrew, taking into consideration the proper legislation and the satisfaction of the crew members. The CSP is usually divided into two independent subproblems, modeled and solved sequentially: Crew Pairing Problem (CPP) and Crew Rostering Problem (CRP). This decomposition does not incorporate all the crew members attributes (availability, qualification, seniority and individual preferences), which does not lead to a real cost estimate and affects the quality of the final solution. The state of the art involves the integrated solution of CSP, without solving the CPP at first and providing a more realistic solution. The CSP, however, has a combinatorial nature. This research proposes and explores models based on integer linear programming and on heuristics to solve the CSP in an integrated way. These heuristics incorporate GRASP metaheuristic, Clarke and Wright savings heuristic and day-by-day heuristic. The models were successfully tested to solve instances related to the networks of three Brazilian airlines.
5

Cabin Air Quality in Commercial Aircraft : Exposure, Symptoms and Signs

Lindgren, Torsten January 2003 (has links)
<p>The objective of the dissertation was to study the cabin environment, and identify personal and environmental risk factors, associated with symptoms, and perception of cabin air quality. Another objective was to study if ban of smoking, and increased relative air humidity on intercontinental flights, could have a beneficial health effect. The studies were performed among Scandinavian cabin crew in one Airline Company. Office workers from the same company served as controls. Exposure differed between cruise and non-cruise conditions. Air humidity was very low during intercontinental flights (3-8%). Concentration of moulds, bacteria, formaldehyde, and ozone was low. Tobacco smoking increased respirable particles in the cabin air, from 3 to 49 mg/m3, and increased cotinine in urine. The ETS-exposure was highest in the aft part of the cabin. Symptoms and environmental complaints were more common among flight crew than office workers. We could identify personal factors of importance, and certain conditions that could be improved, to achieve a better cabin environment. There was an association between symptoms and environmental perceptions and work stress, lack of influence on working condition, and a history of atopy. After ban on smoking in aircraft, there was a decrease of ocular and general symptoms, and increased tear-film stability in aircrew. Air humidification reduced headache and ocular, nasal, and dermal dryness symptoms, increased tear-film stability, and increased nasal patency. Our result indicates that ETS and low air humidity are important environmental factors in aircraft, and that atopy, and work stress could be significant risk factors for symptoms and environmental perceptions.</p>
6

Cabin Air Quality in Commercial Aircraft : Exposure, Symptoms and Signs

Lindgren, Torsten January 2003 (has links)
The objective of the dissertation was to study the cabin environment, and identify personal and environmental risk factors, associated with symptoms, and perception of cabin air quality. Another objective was to study if ban of smoking, and increased relative air humidity on intercontinental flights, could have a beneficial health effect. The studies were performed among Scandinavian cabin crew in one Airline Company. Office workers from the same company served as controls. Exposure differed between cruise and non-cruise conditions. Air humidity was very low during intercontinental flights (3-8%). Concentration of moulds, bacteria, formaldehyde, and ozone was low. Tobacco smoking increased respirable particles in the cabin air, from 3 to 49 mg/m3, and increased cotinine in urine. The ETS-exposure was highest in the aft part of the cabin. Symptoms and environmental complaints were more common among flight crew than office workers. We could identify personal factors of importance, and certain conditions that could be improved, to achieve a better cabin environment. There was an association between symptoms and environmental perceptions and work stress, lack of influence on working condition, and a history of atopy. After ban on smoking in aircraft, there was a decrease of ocular and general symptoms, and increased tear-film stability in aircrew. Air humidification reduced headache and ocular, nasal, and dermal dryness symptoms, increased tear-film stability, and increased nasal patency. Our result indicates that ETS and low air humidity are important environmental factors in aircraft, and that atopy, and work stress could be significant risk factors for symptoms and environmental perceptions.

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