A presente pesquisa tem como objetivo estudar a integração entre dois temas clássicos da literatura de pesquisa operacional e gestão de operações: problemas de corte e empacotamento; e problemas de programação da produção. Ainda que sejam duas áreas intensamente exploradas e pesquisadas, e, ainda, que seja uma situação facilmente encontrada em sistemas de produção reais, abordagens de ambos problemas de forma coordenada ainda carecem de maiores pesquisas. Neste trabalho é feita uma revisão de ambos temas, com foco em problemas de bin packing e programação em ambiente de máquina única com objetivo de minimizar soma de atrasos e adiantamentos ponderados. Uma formulação matemática linear e inteira mista é proposta para o problema, contemplando as restrições que concernem a cada um e também à sua consideração simultânea. Como se trata de um problema que une dois outros, cada um NP-hard isoladamente, um método heurístico é proposto para obter uma solução interessante em tempos computacionais bastante reduzidos. Foram obtidas propriedades físicas de definição de data ideal de programação de um conjunto de itens atribuídos a um bin. Também é proposto um método para geração de um limitante inferior melhorado em relação a pacotes de otimização de mercado para o problema. Ambos métodos foram testados em uma massa de dados de 1.152 instâncias, geradas para retratar cenários de diferentes datas de entrega, setups, custos de atraso e adiantamento em relação à matéria-prima, tamanho de itens e número de itens na instância. Os resultados mostram-se largamente superiores aos obtidos por um otimizador genérico (CPLEX), embora ainda sejam gaps excessivamente grandes, o que reforça a dificuldade do problema. / The present research aims to explore the integration between two classic themes on operations research and operations management literature: cutting and packing problems; and production scheduling problems. Although they are intensive explored and researched areas and, besides, it\'s an easily found situation on real production systems, coordinated approaches of both themes still need deeper research. On this paper, it was done a review of both themes, focusing on bin packing problems and single-machine environment scheduling problems aiming to minimize total weighed earliness and tardiness. A mixed integer-linear mathematical formulation is proposed to the problem, including constraints referred to each problem and, also, to their simultaneous consideration. Once it\'s a problem that joins the other two, each one NP-hard solely, an heuristic method is proposed to obtain an interesting solution in reasonable computational times. Physical properties were identified, defining the best date to allocate a given lot of items to be processed together. Also, a lower bound generation method is proposed, improving the one generated by optimization softwares. Both methods were tested on a 1.152 instances mass of data, generated to represent well several scenarios of different due dates, setup times, earliness and tardiness costs compared to raw material, size of items and number the items the instance. Results show largely superiority the ones obtained by an optimization pack (CPLEX), although gaps are still excessively large, fact the reinforces problem\'s difficulty.

No description available.

Durant cette thèse, nous avons introduit les problèmes de Bin Covering avec Contrainte de Distance (BCCD) et de Bin Packing avec Contrainte de Distance (BPCD), qui trouvent leur application dans les réseaux de grande échelle, tel Internet. L'étude de ces problèmes que nous effectuons dans des espaces métriques quelconques montre qu'il est impossible de travailler dans un tel cadre sans avoir recours à de l'augmentation de ressources, un procédé qui permet d'élaborer des algorithmes construisant des solutions moins contraintes que la solution optimale à laquelle elles sont comparées. En plus de résultats d'approximation intéressants, nous prouvons la difficulté de ces problèmes si ce procédé n'est pas utilisé. Par ailleurs, de nombreux outils ont pour objectif de plonger les grands réseaux qui nous intéressent dans des espaces métriques bien décrits. Nous avons alors étudié nos problèmes dans plusieurs espaces métriques spécifiques, et, en particulier, ceux générés par certains de ces outils, comme Vivaldi et Sequoia. / During this Ph.D we introduced Bin Covering under Distance Constraint (BCCD in French) and Bin Packing under Distance Constraint (BPCD in French). Those two problems find their applications in the context of large scale networks, like Internet. We studied those problems in general metric spaces, and proved that using resource augmentation is mandatory. Resource augmentation allows to build algorithms working on solutions with less constraints than the optimal solution to which it is compared to. We found interesting approximations algorithms using this relaxation, and proved the necessity of this resource augmentation. However many tools are used to embed large networks we are interested in in specific metric spaces. Thus we studied those problems in different specific metric spaces, in particular those generated by the use of Vivaldi and Sequoia, two of those tools.

This study considered using a relatively new method to study soil-tool wear which could drastically reduce the time and associated costs of traditional wear studies. The goal was to utilize discrete element method (DEM) simulations to recreate the results of a circular soil bin test in order to develop a relationship that could be used to predict wear under different conditions. Through the application of DEM, simulations could be used to study different materials or designs intended to result in improved wear performance.<p> Three replications of aluminum cylindrical bars were worn during 400 km of travel in a circular soil bin. Wear was quantified by measuring the change in radius of the cylinders at 18-degree intervals around their circumference. Mass data were also obtained to provide an overall average of wear occurring on the bar and to validate the radii measurements.<p> The DEM simulations were executed using EDEM software. Conditions present in the physical soil bin trials were simulated by recreating components in the soil bin and incorporating soil properties that were directly measured, using representative soil samples. Forces exerted on the bar by the soil and the relative velocities between the soil and tool were used to generate a relationship to predict wear of the bar. The wear equation was verified using a portion of the experimental data from the soil bin.<p> The wear model showed promise in predicting the amount of wear recorded in the soil bin through the application of DEM-predicted compressive forces and relative velocities between the tool and soil particles. The Archard equation for wear was modified to create a non-linear equation. Plotting the measured wear against the wear predicted from the fitted equation produced a trendline with a slope of 0.65. Although a perfect correlation would have produced a slope of 1, the model was able to predict a large portion of the wear that occurred. Refinement of the model could further be achieved with changes in the design of the geometry used in the simulation and through verification of force predictions with experimental data. Because of the variable nature of wear, additional replications of tools in the soil bin would have increased the number of data points available to create the model and reduced the impact of outlying data. With these recommended improvements, the wear model has the ability to very accurately predict the wear of a cylindrical bar.

This study considered using a relatively new method to study soil-tool wear which could drastically reduce the time and associated costs of traditional wear studies. The goal was to utilize discrete element method (DEM) simulations to recreate the results of a circular soil bin test in order to develop a relationship that could be used to predict wear under different conditions. Through the application of DEM, simulations could be used to study different materials or designs intended to result in improved wear performance.<p> Three replications of aluminum cylindrical bars were worn during 400 km of travel in a circular soil bin. Wear was quantified by measuring the change in radius of the cylinders at 18-degree intervals around their circumference. Mass data were also obtained to provide an overall average of wear occurring on the bar and to validate the radii measurements.<p> The DEM simulations were executed using EDEM software. Conditions present in the physical soil bin trials were simulated by recreating components in the soil bin and incorporating soil properties that were directly measured, using representative soil samples. Forces exerted on the bar by the soil and the relative velocities between the soil and tool were used to generate a relationship to predict wear of the bar. The wear equation was verified using a portion of the experimental data from the soil bin.<p> The wear model showed promise in predicting the amount of wear recorded in the soil bin through the application of DEM-predicted compressive forces and relative velocities between the tool and soil particles. The Archard equation for wear was modified to create a non-linear equation. Plotting the measured wear against the wear predicted from the fitted equation produced a trendline with a slope of 0.65. Although a perfect correlation would have produced a slope of 1, the model was able to predict a large portion of the wear that occurred. Refinement of the model could further be achieved with changes in the design of the geometry used in the simulation and through verification of force predictions with experimental data. Because of the variable nature of wear, additional replications of tools in the soil bin would have increased the number of data points available to create the model and reduced the impact of outlying data. With these recommended improvements, the wear model has the ability to very accurately predict the wear of a cylindrical bar.

No description available.

This dissertation explores the composition, construction and framing of Al-Qa'ida leadership communiqués – understood as the statements, messages, interviews, written work and other output from the movement's predominant leaders: Usama bin Ladin and Ayman al-Zawahiri. The thesis argues existing research into this corpus is insufficiently rigorous, systematic and comprehensive in scope, thus failing to elucidate nuances and dynamics in the narrative of the Al-Qa'ida leadership since the movement's inception. The current study presents results from the coding of 240 communiqués produced by the two leaders from 1991 to August 2011. The analysis was informed by the literature on Collective Action Frames, which understands this material as the communicative effort of movement leaders towards identified audiences and constituents. This approach divides each message according to diagnostic, prognostic and motivational appeals contained within the narrative and assesses the impact of this collective according to its narrative fidelity (as regards the wider socio-cultural milieu), empirical credibility (in terms of consistency and continuity) and experiential commensurability (in light of experiences and realities of designated constituents). The dissemination of communiqués highlighting the values, aspirations, frustrations and grievances of Al-Qa'ida is a central objective of its leadership. This material provides the metrics to understand the way in which the movement has evolved since its formation. The leaders themselves recognise the importance of communicating with diverse audiences in this way. The longitudinal analysis of the leadership communiqués, however, found that bin Ladin and Zawahiri failed to present coherent justifications for the solutions presented or how they should be focused. Moreover, it found that the leadership failed to reflect the interests of the vast majority of Muslims, particularly in the West, and gradually denounced those it claims to represent – the Muslim ummah. This dissertation thus illustrates how Al-Qa'ida has failed as a revolutionary vanguard based on evidence garnered from a systematic and long-term analysis of the leadership's communiqués.

Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, June 2009. / Thesis Advisor(s): Roberts, Nancy. "June 2009." Description based on title screen as viewed on 13 July 2009. Author(s) subject terms: Al Qaeda, Osama bin Laden, charisma, charismatic, radicalism, terrorism, insurgencies, radical social movements, cohesion, power structure, flux, control, communion, stability, Islam, Islamic. Includes bibliographical references (p. 139-145). Also available in print.

Thesis (Ph. D.)--Ohio State University, 2007. / Full text release at OhioLINK's ETD Center delayed at author's request

University, Diss., 2003--Kiel.