This thesis explores mining the evolutionary history of a software system to support software developers and managers in their endeavors to build and maintain complex software systems. We introduce the idea of evolutionary extractors which are specialized extractors that can recover the history of software projects from software repositories, such as source control systems. The challenges faced in building C-REX, an evolutionary extractor for the C programming language, are discussed. We examine the use of source control systems in industry and the quality of the recovered C-REX data through a survey of several software practitioners. Using the data recovered by C-REX, we develop several approaches and techniques to assist developers and managers in their activities. We propose <em>Source Sticky Notes</em> to assist developers in understanding legacy software systems by attaching historical information to the dependency graph. We present the <em>Development Replay</em> approach to estimate the benefits of adopting new software maintenance tools by reenacting the development history. We propose the <em>Top Ten List</em> which assists managers in allocating testing resources to the subsystems that are most susceptible to have faults. To assist managers in improving the quality of their projects, we present a complexity metric which quantifies the complexity of the changes to the code instead of quantifying the complexity of the source code itself. All presented approaches are validated empirically using data from several large open source systems. The presented work highlights the benefits of transforming software repositories from static record keeping repositories to active repositories used by researchers to gain empirically based understanding of software development, and by software practitioners to predict, plan and understand various aspects of their project.

When performing an analysis of the evolution of software quality and software metrics,there is a need to get access to as many versions of the source code as possible. There isa lack of research on how data or source code can be extracted from the source controlmanagement system Git. This thesis explores different possibilities to resolve thisproblem. Lately, there has been a boom in usage of the version control system Git. Githubalone hosts about 6,100,000 projects. Some well known projects and organizations thatuse Git are Linux, WordPress, and Facebook. Even with these figures and clients, thereare very few tools able to perform data extraction from Git repositories. A pre-studyshowed that there is a lack of standardization on how to share mining results, and themethods used to obtain them. There are several tools available for older version control systems, such as concurrentversions system (CVS), but few for Git. The examined repository mining applicationsfor Git are either poorly documented; or were built to be very purpose-specific to theproject for which they were designed. This thesis compiles a list of general issues encountered when using repositorymining as a tool for data gathering. A selection of existing repository mining tools wereevaluated towards a set of prerequisite criteria. The end result of this evaluation is thecreation of a new repository mining tool called Doris. This tool also includes a smallcode metrics analysis library to show how it can be extended.

A infiltração das águas de chuva dentro dos lotes urbanos é uma possível forma de promover o controle descentralizado do escoamento superficial na origem, com vistas ao gerenciamento das águas pluviais urbanas e conseqüente atenuação das cheias. Neste trabalho, foram conduzidos ensaios de campo com trincheiras de infiltração, em dois solos distintos, um arenoso e outro argiloso, com o objetivo de avaliar quantitativamente o comportamento hidráulico das estruturas de infiltração em resposta a volumes de escoamento. As trincheiras foram alimentadas com volumes de água controlados, e o campo de umidade do experimento foi monitorado com sonda de nêutrons, durante o processo de redistribuição da água no solo. Foi realizada a modelagem matemática do fenômeno bidimensional de infiltração em torno de trincheiras de seção retangular, em resposta à entrada de águas pluviais provenientes de áreas impermeabilizadas contíguas. A comparação entre os resultados experimentais e simulados pela equação bidimensional de Richards indica uma pequena defasagem dos valores de volume infiltrado e umidade do solo nos processos de infiltração e drenagem interna simulados em relação aos observados. A capacidade de infiltração da trincheira mostrou-se maior nos dados observados, possivelmente devido à simplificação de distribuição unimodal dos diâmetros dos poros adotada na modelagem numérica, uma vez que, experimentalmente, observou-se multimodalidade nos dois solos estudados. A curva de van Genuchten é, juntamente com a equação de Richards, a base do modelo computacional, e divergências no seu ajuste em relação aos dados observados podem conduzir a pequenas divergências dos volumes infiltrados e perfis de umidade ao longo do processo de infiltração simulado, em relação ao observado. São apresentadas algumas considerações de dimensionamento sobre a implantação de trincheiras de infiltração em lotes residenciais, bem como discussões com respeito aos planos diretores urbanos. É apresentado um estudo simplificado, baseado no método racional, sobre a redução no hidrograma de cheia proporcionada pelo uso de trincheiras em uma micro bacia urbana, o qual revelou reduções da ordem de até 94% do deflúvio superficial direto gerado pelo lote. / Stormwater infiltration process at the scale of housing is a possible way to promote the decentralized runoff control in order to manage the urban water and to attenuate flood peaks. In this work, field essays with infiltration devices at two different soils, either sandy and clay-loam soils, are assessed in order to study the hydraulic behavior of infiltration trenches to attenuate incoming runoff volume inputs. The infiltration trench experiments set a controlled water supply for specific boundary conditions, and the experimental moisture field were monitored with neutron probe during the water redistribution process at soil core. Bi-dimensional (2D) mathematical modeling is depicted at specific boundary conditions with a rectangular-trench layout, thereby mimicking a potential situation of runoff incoming from adjacent impervious areas. The comparison between experimental and numerical results, simulated by two-dimensional Richards\' equation, shows a small lag-time difference of both infiltrated volumes and soil moisture contents during infiltration and drainage periods. The trench infiltration capacity of observed data appears to be greater than simulated results, possibly due to an overall simplification of a uni-modal, homogeneous pore diameter distribution adopted by the modeling scheme. Experimental retention curves outline indirect evidences of multi-modal, heterogeneous behavior of pore structure. Bon van Genutchen-type retention curve and Richards-momentum equations represent the baseline approach to the computational model of non-saturated soils. Some fitting discrepancies between observed and simulated results could lead to negligible different estimations of infiltrated volumes and moisture profiles. Finally, further discussions on project design and best management practices (BMPs) of infiltration trenches at housing scale as well discussions on urban master plan are outlined herewith. A simplified study, based on rational method, is presented on the reduction of incoming hydrograph with the use of infiltration trenches. Preliminary results perform volume reductions of approximately 94% from incoming runoff generated at housing lots.

A infiltração das águas de chuva dentro dos lotes urbanos é uma possível forma de promover o controle descentralizado do escoamento superficial na origem, com vistas ao gerenciamento das águas pluviais urbanas e conseqüente atenuação das cheias. Neste trabalho, foram conduzidos ensaios de campo com trincheiras de infiltração, em dois solos distintos, um arenoso e outro argiloso, com o objetivo de avaliar quantitativamente o comportamento hidráulico das estruturas de infiltração em resposta a volumes de escoamento. As trincheiras foram alimentadas com volumes de água controlados, e o campo de umidade do experimento foi monitorado com sonda de nêutrons, durante o processo de redistribuição da água no solo. Foi realizada a modelagem matemática do fenômeno bidimensional de infiltração em torno de trincheiras de seção retangular, em resposta à entrada de águas pluviais provenientes de áreas impermeabilizadas contíguas. A comparação entre os resultados experimentais e simulados pela equação bidimensional de Richards indica uma pequena defasagem dos valores de volume infiltrado e umidade do solo nos processos de infiltração e drenagem interna simulados em relação aos observados. A capacidade de infiltração da trincheira mostrou-se maior nos dados observados, possivelmente devido à simplificação de distribuição unimodal dos diâmetros dos poros adotada na modelagem numérica, uma vez que, experimentalmente, observou-se multimodalidade nos dois solos estudados. A curva de van Genuchten é, juntamente com a equação de Richards, a base do modelo computacional, e divergências no seu ajuste em relação aos dados observados podem conduzir a pequenas divergências dos volumes infiltrados e perfis de umidade ao longo do processo de infiltração simulado, em relação ao observado. São apresentadas algumas considerações de dimensionamento sobre a implantação de trincheiras de infiltração em lotes residenciais, bem como discussões com respeito aos planos diretores urbanos. É apresentado um estudo simplificado, baseado no método racional, sobre a redução no hidrograma de cheia proporcionada pelo uso de trincheiras em uma micro bacia urbana, o qual revelou reduções da ordem de até 94% do deflúvio superficial direto gerado pelo lote. / Stormwater infiltration process at the scale of housing is a possible way to promote the decentralized runoff control in order to manage the urban water and to attenuate flood peaks. In this work, field essays with infiltration devices at two different soils, either sandy and clay-loam soils, are assessed in order to study the hydraulic behavior of infiltration trenches to attenuate incoming runoff volume inputs. The infiltration trench experiments set a controlled water supply for specific boundary conditions, and the experimental moisture field were monitored with neutron probe during the water redistribution process at soil core. Bi-dimensional (2D) mathematical modeling is depicted at specific boundary conditions with a rectangular-trench layout, thereby mimicking a potential situation of runoff incoming from adjacent impervious areas. The comparison between experimental and numerical results, simulated by two-dimensional Richards\' equation, shows a small lag-time difference of both infiltrated volumes and soil moisture contents during infiltration and drainage periods. The trench infiltration capacity of observed data appears to be greater than simulated results, possibly due to an overall simplification of a uni-modal, homogeneous pore diameter distribution adopted by the modeling scheme. Experimental retention curves outline indirect evidences of multi-modal, heterogeneous behavior of pore structure. Bon van Genutchen-type retention curve and Richards-momentum equations represent the baseline approach to the computational model of non-saturated soils. Some fitting discrepancies between observed and simulated results could lead to negligible different estimations of infiltrated volumes and moisture profiles. Finally, further discussions on project design and best management practices (BMPs) of infiltration trenches at housing scale as well discussions on urban master plan are outlined herewith. A simplified study, based on rational method, is presented on the reduction of incoming hydrograph with the use of infiltration trenches. Preliminary results perform volume reductions of approximately 94% from incoming runoff generated at housing lots.