This thesis aims to study the theoretical complexity and empirical performance of decomposition algorithms. We focus on linear programs with a block-angular structure. Decomposition algorithms used to be the only way to solve large-scale special structured problems, in terms of memory limit and CPU time. However, with the advances in computer technology over the past few decades, many large-scale problems can now be solved simply by using some general purpose LP software, without exploiting the problems' inner structures. A question arises naturally, should we solve a structured problem with decomposition, or directly solve it as a whole? We try to understand how a problem's characteristics influence its computational performance, and compare the relative efficiency of algorithms with and without decomposition. Two comparisons are conducted in our research: first, the Dantzig-Wolfe decomposition method (DW) versus the simplex method (simplex); second, the analytic center cutting plane method (ACCPM) versus the interior point method (IPM). These comparisons fall into the two main solution approaches in linear programming: simplex-based algorithms and IPM-based algorithms. Motivated by our observations of ACCPM and DW decomposition, we devise a hybrid algorithm combining ACCPM and DW, which are the counterparts of IPM and simplex in the decomposition framework, to take the advantages of both: the quick convergence rate of IPM-based methods, as well as the accuracy of simplex-based algorithms. A large set of 316 instances is incorporated in our experiments, so that different dimensioned problems with primal or dual block-angular structures are covered to test our conclusions.

Os solos das regiões arrozeiras apresentam características geotécnicas inadequadas para uso como revestimentos primários de estradas. Isto força o transporte de materiais de jazidas distantes, o que, além de onerar o custo de construção, nem sempre é uma solução durável. Nesta tese relata-se uma pesquisa que apresenta uma solução para esse problema: a pavimentação de estradas de baixo volume de tráfego com solo local modificado com cal. Foram realizados estudos laboratoriais e de campo, e os resultados analisados através de uma abordagem mecanístico-empírica. Dois pavimentos experimentais com revestimentos de solo-cal foram construídos e monitorados próximo a Cebollatí, leste do Uruguai. Foram realizados ensaios de caracterização e comportamento mecânico do solo e de misturas de solo e cal, variando-se o teor de cal, o tempo de cura e a energia de compactação. Realizaram-se ensaios de módulo de resiliência, para o qual foi projetado, montado e operado o primeiro equipamento de ensaios de carga repetida na compressão triaxial do Uruguai. Também foram realizados ensaios de fadiga na compressão diametral para o solo modificado com 3% e 5% de cal, curado por 28 e 150 dias. Para entender o comportamento das camadas de solo modificado com cal submetidas ao tráfego, realizou-se uma análise conjunta dos resultados laboratoriais e do monitoramento dos trechos experimentais, com uso de modelos computacionais. Apesar das limitações construtivas, de terem sido liberados ao tráfego em plena safra e das más condições de drenagem da região, após 5 anos de trafego, os pavimentos não mostram trincas de fadiga ou afundamentos nas trilhas de roda. Assim, a pavimentação de estradas de baixo volume de tráfego em regiões arrozeiras com revestimentos de solo local modificado com cal provou ser uma alternativa economicamente vantajosa, por reduzir custos de construção e manutenção, e sustentável, por preservar materiais não-renováveis, como solos e rochas. / Soils in rice plantation areas generally present geotechnical characteristics unsuitable for use as primary wearing course of roads. Because of that, it is necessary to import materials from distant sites, a solution that, besides increasing construction cost, is rarely long-lasting. In this thesis a research on paving low volume roads with lime modified local soils is reported, in order to present an alternative solution to that problem. Both laboratory and field studies were carried out and the results were analyzed by means of a mechanistic-empirical approach. Two test sections with wearing courses made of lime modified soil were built and monitored close to Cebollatí, a village in the east of Uruguay. Previously, laboratory characterization and mechanical tests on samples of the sedimentary soil were carried out. Lime contents for mixtures were determined and the stress-strain-strength behavior of mixes with different levels of lime content, curing time and compaction energy was studied. In order to analyze the elastic behavior of the lime modified soil under traffic, resilient modulus tests were carried out. This motivated the design, assembly and use of the first equipment for triaxial compression repeated loading tests in Uruguay. Besides, stress controlled fatigue tests were performed on cylindrical specimens of soil modified with 3% and 5% of lime, cured for 28 and 150 days. The results of laboratory tests and field monitoring were analyzed using computational models. In spite of the difficulties faced during pavements construction, including heavy traffic in early days, and the poor drainage, after 5 years of service no cracks or ruts are seen on top of the test pavements. Therefore, paving low volume roads in rice plantation areas with lime modified wearing courses has proved to be a cost-effective alternative, reducing construction and maintenance costs, and a sustainable practice, preserving non-renewable materials such as rocks and soils.

Os solos das regiões arrozeiras apresentam características geotécnicas inadequadas para uso como revestimentos primários de estradas. Isto força o transporte de materiais de jazidas distantes, o que, além de onerar o custo de construção, nem sempre é uma solução durável. Nesta tese relata-se uma pesquisa que apresenta uma solução para esse problema: a pavimentação de estradas de baixo volume de tráfego com solo local modificado com cal. Foram realizados estudos laboratoriais e de campo, e os resultados analisados através de uma abordagem mecanístico-empírica. Dois pavimentos experimentais com revestimentos de solo-cal foram construídos e monitorados próximo a Cebollatí, leste do Uruguai. Foram realizados ensaios de caracterização e comportamento mecânico do solo e de misturas de solo e cal, variando-se o teor de cal, o tempo de cura e a energia de compactação. Realizaram-se ensaios de módulo de resiliência, para o qual foi projetado, montado e operado o primeiro equipamento de ensaios de carga repetida na compressão triaxial do Uruguai. Também foram realizados ensaios de fadiga na compressão diametral para o solo modificado com 3% e 5% de cal, curado por 28 e 150 dias. Para entender o comportamento das camadas de solo modificado com cal submetidas ao tráfego, realizou-se uma análise conjunta dos resultados laboratoriais e do monitoramento dos trechos experimentais, com uso de modelos computacionais. Apesar das limitações construtivas, de terem sido liberados ao tráfego em plena safra e das más condições de drenagem da região, após 5 anos de trafego, os pavimentos não mostram trincas de fadiga ou afundamentos nas trilhas de roda. Assim, a pavimentação de estradas de baixo volume de tráfego em regiões arrozeiras com revestimentos de solo local modificado com cal provou ser uma alternativa economicamente vantajosa, por reduzir custos de construção e manutenção, e sustentável, por preservar materiais não-renováveis, como solos e rochas. / Soils in rice plantation areas generally present geotechnical characteristics unsuitable for use as primary wearing course of roads. Because of that, it is necessary to import materials from distant sites, a solution that, besides increasing construction cost, is rarely long-lasting. In this thesis a research on paving low volume roads with lime modified local soils is reported, in order to present an alternative solution to that problem. Both laboratory and field studies were carried out and the results were analyzed by means of a mechanistic-empirical approach. Two test sections with wearing courses made of lime modified soil were built and monitored close to Cebollatí, a village in the east of Uruguay. Previously, laboratory characterization and mechanical tests on samples of the sedimentary soil were carried out. Lime contents for mixtures were determined and the stress-strain-strength behavior of mixes with different levels of lime content, curing time and compaction energy was studied. In order to analyze the elastic behavior of the lime modified soil under traffic, resilient modulus tests were carried out. This motivated the design, assembly and use of the first equipment for triaxial compression repeated loading tests in Uruguay. Besides, stress controlled fatigue tests were performed on cylindrical specimens of soil modified with 3% and 5% of lime, cured for 28 and 150 days. The results of laboratory tests and field monitoring were analyzed using computational models. In spite of the difficulties faced during pavements construction, including heavy traffic in early days, and the poor drainage, after 5 years of service no cracks or ruts are seen on top of the test pavements. Therefore, paving low volume roads in rice plantation areas with lime modified wearing courses has proved to be a cost-effective alternative, reducing construction and maintenance costs, and a sustainable practice, preserving non-renewable materials such as rocks and soils.

Os solos das regiões arrozeiras apresentam características geotécnicas inadequadas para uso como revestimentos primários de estradas. Isto força o transporte de materiais de jazidas distantes, o que, além de onerar o custo de construção, nem sempre é uma solução durável. Nesta tese relata-se uma pesquisa que apresenta uma solução para esse problema: a pavimentação de estradas de baixo volume de tráfego com solo local modificado com cal. Foram realizados estudos laboratoriais e de campo, e os resultados analisados através de uma abordagem mecanístico-empírica. Dois pavimentos experimentais com revestimentos de solo-cal foram construídos e monitorados próximo a Cebollatí, leste do Uruguai. Foram realizados ensaios de caracterização e comportamento mecânico do solo e de misturas de solo e cal, variando-se o teor de cal, o tempo de cura e a energia de compactação. Realizaram-se ensaios de módulo de resiliência, para o qual foi projetado, montado e operado o primeiro equipamento de ensaios de carga repetida na compressão triaxial do Uruguai. Também foram realizados ensaios de fadiga na compressão diametral para o solo modificado com 3% e 5% de cal, curado por 28 e 150 dias. Para entender o comportamento das camadas de solo modificado com cal submetidas ao tráfego, realizou-se uma análise conjunta dos resultados laboratoriais e do monitoramento dos trechos experimentais, com uso de modelos computacionais. Apesar das limitações construtivas, de terem sido liberados ao tráfego em plena safra e das más condições de drenagem da região, após 5 anos de trafego, os pavimentos não mostram trincas de fadiga ou afundamentos nas trilhas de roda. Assim, a pavimentação de estradas de baixo volume de tráfego em regiões arrozeiras com revestimentos de solo local modificado com cal provou ser uma alternativa economicamente vantajosa, por reduzir custos de construção e manutenção, e sustentável, por preservar materiais não-renováveis, como solos e rochas. / Soils in rice plantation areas generally present geotechnical characteristics unsuitable for use as primary wearing course of roads. Because of that, it is necessary to import materials from distant sites, a solution that, besides increasing construction cost, is rarely long-lasting. In this thesis a research on paving low volume roads with lime modified local soils is reported, in order to present an alternative solution to that problem. Both laboratory and field studies were carried out and the results were analyzed by means of a mechanistic-empirical approach. Two test sections with wearing courses made of lime modified soil were built and monitored close to Cebollatí, a village in the east of Uruguay. Previously, laboratory characterization and mechanical tests on samples of the sedimentary soil were carried out. Lime contents for mixtures were determined and the stress-strain-strength behavior of mixes with different levels of lime content, curing time and compaction energy was studied. In order to analyze the elastic behavior of the lime modified soil under traffic, resilient modulus tests were carried out. This motivated the design, assembly and use of the first equipment for triaxial compression repeated loading tests in Uruguay. Besides, stress controlled fatigue tests were performed on cylindrical specimens of soil modified with 3% and 5% of lime, cured for 28 and 150 days. The results of laboratory tests and field monitoring were analyzed using computational models. In spite of the difficulties faced during pavements construction, including heavy traffic in early days, and the poor drainage, after 5 years of service no cracks or ruts are seen on top of the test pavements. Therefore, paving low volume roads in rice plantation areas with lime modified wearing courses has proved to be a cost-effective alternative, reducing construction and maintenance costs, and a sustainable practice, preserving non-renewable materials such as rocks and soils.

[pt] Custos de troca existentes em certas indústrias são capazes de fornecer poder de mercado para as firmas que os detêm. O que se espera é que estes custos diminuam a concorrência entre as firmas uma vez que consumidores estarão mais inelásticos a variações de preço. No entanto, o que se nota neste trabalho é que dependendo da maturidade do mercado, firmas podem estar concorrendo por market share mais agressivamente para posteriormente aproveitar o custo de troca e o respectivo poder de mercado gerado por este custo. O que se observa no modelo é que se o custo de troca for diminuído em um momento de concorrência para obtenção de market share, preços podem aumentar. Este estudo analisa empiricamente a ocorrência da lei da portabilidade numérica no mercado de telefonia focando os efeitos na concorrência. / [en] Existing switching costs in certain industries are capable of providing market power to the holding firms. It s expected that these switching costs reduce the competition between the firms, as the consumers would likely to be more inelastic to the price variations. However, what s noticed in this paper is that depending of the market maturity; firms could be greedily competing for the market share to posteriorly take advantage of the switching cost. What s noticed is that if the switching cost is reduced in a competition moment of obtaining the marked share, prices would raise. This paper focuses the empirical study of the occurrence of the number portability in the phone market.

Since the 1980s, hemlock-dominated forests (Tsuga canadensis) of central New England have been increasingly infested by the invasive pest hemlock woolly adelgid (HWA, Adelges tsugae), predominantly resulting in its replacement by black birch-dominated forests (Betula lenta). To date there has been no long-term empirical analysis of HWA effects on forest carbon (C) cycling due to forest transition from hemlock to black birch. To address this question, I measured the C pools in five stand types at varying ages and stages of HWA infestation in Massachusetts and Connecticut. I also measured C fluxes in aboveground net primary production (ANPP) and soil respiration, and studied the drivers of these fluxes viz. litter production, rates of foliar decomposition, soil exoenzyme activity, temperature sensitivity of soil respiration and nitrogen (N) cycling. The mass of C stored in recovering forests was resilient to HWA infestation but the location of these stocks varied among stand types. There was a transition of C from live biomass in healthy, unaffected secondary hemlock forests to coarse woody debris (CWD) in recently girdled forests intended to simulate the effect of HWA on hemlock loss. Twenty years post-HWA infestation, however, ANPP was very high and there was a large increase in biomass-C pools in aggrading black stand types. C pools in mature, secondary black birch stand types ~135 years since pastureland abandonment were as large as those in primary hemlock stand types ~235 years of age, suggesting recovery of C storage within one century of HWA infestation. Soil respiration rates were positively correlated with inputs of hardwood leaf litter, fine root biomass and exoenzyme activity. Stand-type variations in ANPP were positively correlated with annual N requirements and N uptake from the soil. Nitrogen-use efficiency was highest in the girdled and post-HWA infestation stand types where ANPP was dominated by wood production which has a wide C:N ratio. Similar trends were found in soil respiration, but not to the same degree as that of ANPP. Collectively, my results indicate that southern New England forests C storage is highly resilient to the HWA-induced losses of hemlock, suggesting that these ecosystems will continue to be sinks for atmospheric carbon dioxide.

In the present study, a neoclassical general equilibrium model is developed to study the dualistic economic development of a predominantly agrarian economy, Bangladesh. Quantitative analysis is undertaken in order to make assessments of several development strategies within the framework of the model. The linkages between the agricultural (rural) and the manufacturing (urban) sectors via the output and labour markets are incorporated in the model and empirical analysis. In specifying the aggregate relations in the model especially those of the rural sector, the analysis is based on the microeconomic relations of a 'representative peasant household'. The approach is to first estimate the structural parameters of the model (simultaneous system) and then to perform simulation exercises. These simulations permit us to move beyond the restrictions of growth theory, since the direction of influences on different variables and their quantitative dimensions may be assessed. The aim is to determine the differential impact of exogenous investments and related public policy measares on the two sectors, especially on the level of employment, output and wages. Within a disequilibrium growth process which allows for differences in wages in the two sectors, the impact of rural-urban migration of people on the economy of Bangladesh and its policy implications are assessed. The policy simulations suggest that strategies which favour agricultural rather than industrial development have a more positive impact on output, employment, and the reduction of rural-to-urban migration of people. / Thesis / Doctor of Philosophy (PhD)

L’originalité de la musique arabe tient dans la richesse mélodique et rythmique de ses multiplesinfluences. Toutefois, la particularité de son mode de transmission orale, ainsi que l’utilisationintensive et récurrente de l’improvisation, rendent difficile toute classification et archivage, pourtantindispensables à la sauvegarde de ce patrimoine culturel. Or, les tentatives de transcription musicale sesont soldées par de trop nombreuses simplifications, au point de sacrifier les nuances mélodiques etautres finesses techniques, spécifiques à cette musique.Il était nécessaire d’explorer une nouvelle voie, qui permettrait de la sauvegarder sur un support écrit,tout en respectant ses spécificités. A partir d’une oeuvre marquante de l’histoire de la musique arabe,la nūba raıt el dhil, présentée par la délégation tunisienne au Congrès du Caire de 1932, nousproposons un système original et inédit de codification, qui permettra de transcrire toutes les subtilitésdes oeuvres traditionnelles ou improvisées, redonnant ainsi aux interprètes leur liberté d'improvisation,tout en leur conservant la faculté de se référer à une partition simplifiée, mais plus fidèle à l'oeuvreoriginale. / The originality of Arabic music is due to its melodic and rhythmic richness, inheritedfrom many influences. However, the particulars of its oral mode of transmission, as well asthe intensive and recurrent usage of improvisation, render any classification and any archivingdifficult, as indispensable as they may be for the conservation of this cultural patrimony.Attempts at musical transcription resulted in excessive simplifications, or recorded onlyone single version, up to the point of sacrificing melodic nuances and other technical finessesspecific to this music. It appeared therefore necessary to try another solution that wouldallow safeguarding this music in writing, while preserving its specificities. On the basis of amemorable work in the history of Arabic music, the nūba raıt el dhil as presented by theTunisian delegation at the Cairo congress of 1932, we propose an original and novel systemof codification, writing down on the one hand the melodic framework resulting from areduction process and on the other hand the ornaments, in abridged form, as applied to thisreduced melody. This notation will allow transcribing all the subtleties of traditional orimprovised works, giving back to the performers their freedom of improvising, whileallowing them to refer to a simplified score more faithful to the original work.

Cette thèse esquisse une réflexion autour de la mutation du langage musical de l’improvisation instrumentale du type istikhbâr en Tunisie à travers le XXe siècle. Une des raisons qui sont à l’origine de cette mutation consiste à la théorisation de la musique tunisienne, intervenue au congrès du Caire de 1932. L’aspect le plus contraignant de ce congrès consiste à adopter une échelle musicale composée de vingt quatre notes équidistantes à l’octave, obtenues par la subdivision de chaque intervalle de demi-ton en deux quart de tons. Ce manuscrit traite en particulier l’évolution des échelles musicales et du comportement de leurs degrés à travers le temps tout en mesurant l’impact de cette nouvelle théorie. Il s’intéresse aussi à l’analyse des propriétés du cheminement mélodique et de la chaîne syntagmatique afin d’élucider les spécificités langagières inhérentes à chaque époque. Ces différents éléments sont ressortis grâce à la mise en oeuvre d’une méthode d’analyse empirique appliquée sur trois improvisations instrumentales A, B et C, jouées respectivement en 1926, 1963 et 1990. / This thesis exposes a reflection on the musical language‘s mutation in instrumental improvisation called istikhbâr in Tunisia through the XXth century. One of the reasons which are at the origin of this mutation is the theorization of Tunisian music taken place at the Cairo’s congress in 1932. The most compelling aspect of this congress is to adopt a musical scale consisting of twenty four equally spaced octave notes, obtained by subdividing each interval of a semitone into two quarter-tones. This manuscript treats particularly the evolution of musical scales and the behavior of their degrees by the time while measuring the impact of this new theory. It is also interested in analyzing the properties of the melodic path and syntagmatic in order to elucidate the characteristics of each period. These elements emerged by the application of an empirical analytic method applied in three instrumental improvisations A, B and C, respectively played in 1926, 1963 and 1990.

Made available in DSpace on 2016-07-27T14:20:01Z (GMT). No. of bitstreams: 1 Fabiola Ribeiro de Moraes Santeiro.pdf: 516590 bytes, checksum: 7fda62f80ca77c11ea5208db2f849244 (MD5) Previous issue date: 2013-03-07 / Studies on coping help to understand about human contexts and on coping skills to everyday demands. This work consists of two parts. In the first one performs an analysis of scientific literature on coping. The sample consists of 294 articles published between 1993 and 2012 in journals indexed to international database SciELO. Several indicators show that the academic production on coping enjoys positive characteristics, among which stands out the occurrence of significant empirical studies. Given the relevance of the study of coping in adolescents, obtained through systematic analysis of the production area, the second part takes place descriptive study about the use of coping strategies in adolescents, students of big Goiânia (N=430) of both genders and aged between 12 and 19 years. There are significant differences in the use of coping strategies as age and gender of the participants. To consolidate the findings presented, further research is desirable. / Estudos sobre coping ajudam a entender sobre contextos humanos e sobre habilidades de enfrentamento às demandas cotidianas. Este trabalho se compõe de duas partes. Na primeira delas realiza-se uma análise de produção científica sobre coping. A amostra é composta por 294 artigos publicados entre 1993 e 2012, em periódicos indexados à base de dados internacional SciELO. Diversos indicadores demonstram que a produção acadêmica sobre coping desfruta de características positivas, dentre as quais se destaca a ocorrência significante de estudos empíricos. Constatada a relevância do estudo sobre coping em adolescentes, obtida por meio do levantamento sistemático da produção na área, na segunda parte realiza-se estudo descritivo sobre o uso de estratégias de coping em adolescentes, escolares da grande Goiânia (N=430), de ambos os sexos e com idades entre 12 e 19 anos. Verificam-se diferenças significativas no uso de estratégias de coping conforme idade e gênero dos participantes. Para consolidação dos achados apresentados, novas pesquisas são desejáveis.