On the use of a multiple view interactive environment for MATLAB and octave program comprehension

WOS:000364988500049 (Nº de Acesso Web of Science)MATLAB or GNU/Octave programs can become very large and complex and therefore difficult to understand and maintain. The objective of this paper is presenting an approach to mitigate this problem, based upon a multiple view interactive environment (MVIE) called OctMiner. The latter provides visual resources to support program comprehension, namely the selection and configuration of several views to meet developers’ needs. For validation purposes, the authors conducted two case studies to characterize the use of OctMiner in the context of software comprehension activities. The results provided initial evidences of its effectiveness to support the comprehension of programs written in the aforementioned languages

How are extreme temperatures changing in Sweden

Global mean temperature has been observed to increase over the last hundred years; this increase is coupled with a global increase of warm extreme indices and a decrease in cold extreme indices. In this study, daily observations of mean and extreme temperatures from ten different weather stations in Sweden during the time period 1961-2010 were analyzed. A warming trend was identified for every data series for all stations at a statistical significance of 99.95% (with one exception at 99.9%). The tendencies differ between the stations where some show a higher increase in mean temperature while others a higher increase in extreme temperatures; the different rate of change is concluded to depend on local and regional weather effects. Northern Sweden is compared to Southern Sweden and the stations in Northern Sweden show a higher warming in cold extreme temperatures (0.04°C/y on average) than in the warm extreme temperatures (0.028°C/y on average). In Southern Sweden there is a higher warming in the warm temperature extremes (0.037°C/y on average) compared to the cold temperature extremes (0.028°C/y on average). During the time period, the stations show an increase of the warm extreme temperatures of 0.8-2.3°C and 0.7-2.5°C for the cold extremes

Uma abordagem matricial para desdobramento de redes de petri utilizando a ferramenta MATLAB

Orientador : Prof. Dr. Marcos CastilhoCoorientador : Prof. Dr. Luis Allan KünzleDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 15/07/2016Inclui referências : f. 55-57Área de concentração : Ciência da computaçãoResumo: Nas últimas décadas, redes de Petri têm sido amplamente utilizadas como ferramenta para modelar, analisar, simular e avaliar o comportamento e desempenho de sistemas com peculiaridades de sincronização, concorrência e compartilhamento de recursos, como sistemas de manufatura, robótica, sistemas de tempo real entre outros. Um dos problemas enfrentados durante a modelagem desses sistemas está na explosão combinatória do número de estados, o que inviabiliza qualquer método de análise que tenha como base a enumeração desses estados, como o grafo de alcançabilidade. McMillan desenvolveu uma técnica conhecida como desdobramento - unfolding, a qual gera uma nova rede, de complexidade menor que a do grafo de alcançabilidade, que permite evitar análises enumerativas em sistemas modelados por redes de Petri. Em 2002, o algoritmo de McMillan foi aperfeiçoado por Esparza, Römer e Vogler, sendo criado o algoritmo ERV Unfolding, implementado nas ferramentas CUnf, MOLE e PUnf. Essas ferramentas são soluções específicas stand-alone, tendo como desvantagem a complexidade dos algoritmos e a consequente dificuldade de manutenção, prejudicando a alteração dos códigos para estudos e simulação de redes de Petri em ambientes distintos. A abordagem matricial de uma rede de Petri permite com maior facilidade, o estudo das propriedades estruturais e comportamentais da rede, sendo inclusive um facilitador para a implementação de um algoritmo de desdobramento, uma vez que a técnica será implementada através de operações matriciais. A abordagem matricial permite também a simulação e validação de projetos, visando minimizar falhas ou interrupções (deadlocks) do sistema. Assim, a presente proposta de dissertação tem como objetivo construir uma abordagem matricial para o desdobramento em redes de Petri, implementando-a como um módulo da ferramenta MATLAB. As implementações serão validadas através de estudo de caso, sendo posteriormente avaliados os resultados obtidos e as limitações da ferramenta em relação aos algoritmos citados. Palavras-chave: Redes de Petri, desdobramento, algoritmos, MATLAB.Abstract: In recent decades, Petri nets have been widely used as a tool to model, analyze, simulate and evaluate the behavior and performance of systems with synchronization peculiarities, competition and resource sharing, as manufacturing systems, robotics, real-time systems among others. One of the problems faced during the modeling of these systems is the combinatorial explosion of the number of states, which prevents any method of analysis which is based on the enumeration of these states, as the states of reachability graph. McMillan created a technique known as split - unfolding, which generates a new network, complexity lower than the reachability graph, thus avoiding enumerative analysis systems modeled by Petri nets. In 2002, the algotirmo McMillan was perfected by Esparza, Römer and Vogler, being created the ERV Unfolding algorithm, implemented in CUnf, MOLE and PUnf tools. These tools are specific stand-alone solutions, with the disadvantage of the complexity of the algorithms and the consequent difficulty of maintenance, damaging the change of codes for studies and simulation of Petri nets in different environments. The matrix approach of a Petri net with greater ease allows the study of the structural and behavioral properties of the network, including being an enabler for implementing an unfolding algorithm, since the technique is implemented using matrix operations. The matrix approach also allows the simulation and design validation to minimize failures or interruptions (deadlocks) system. The proposed thesis aims to build a matrix approach for deployment on Petri nets, implementing it as a module of MATLAB tool. The implementations will be validated through case studies, and later evaluated the results and the limitations of the tool relative to those cited algorithms. Keywords: Petri net, unfolding, algorithm, MATLAB

Insights from the parallel implementation of efficient algorithms for the fractional calculus

This thesis concerns the development of parallel algorithms to solve fractional differential equations using a numerical approach. The methodology adopted is to adapt existing numerical schemes and to develop prototype parallel programs using the MatLab Parallel Computing Toolbox (MPCT). The approach is to build on existing insights from parallel implementation of ordinary differential equations methods and to test a range of potential candidates for parallel implementation in the fractional case. As a consequence of the work, new insights on the use of MPCT for prototyping are presented, alongside conclusions and algorithms for the effective implementation of parallel methods for the fractional calculus. The principal parallel approaches considered in the work include: - A Runge-Kutta Method for Ordinary Differential Equations including the application of an adapted Richardson Extrapolation Scheme - An implementation of the Diethelm-Chern Algorithm for Fractional Differential Equations - A parallel version of the well-established Fractional Adams Method for Fractional Differential Equations - The adaptation for parallel implementation of Lubich's Fractional Multistep Method for Fractional Differential Equations An important aspect of the work is an improved understanding of the comparative diffi culty of using MPCT for obtaining fair comparisons of parallel implementation. We present details of experimental results which are not satisfactory, and we explain how the problems may be overcome to give meaningful experimental results. Therefore, an important aspect of the conclusions of this work is the advice for other users of MPCT who may be planning to use the package as a prototyping tool for parallel algorithm development: by understanding how implicit multithreading operates, controls can be put in place to allow like-for-like performance comparisons between sequential and parallel programs.Ford, Nevill

Objetos de Aprendizaje con eXeLearning y GeoGebra para la definición y representación geométrica de operaciones con vectores y sus aplicaciones

[ES] A menudo durante el aprendizaje de las matemáticas, ciertos conceptos no son bien comprendidos si éstos no están relacionados con la resolución de problemas y/o ejercicios que tengan un significado para los estudiantes; en este caso lo más común es que los conceptos solo sean memorizados y consecuentemente fácilmente olvidados. Intentando solucionar este problema, este proyecto presenta una colección de seis Objetos de Aprendizaje (OA) como propuesta didáctica para la enseñanza de tema “Definición y representación geométrica de operaciones con vectores y sus aplicaciones”. Para que hasta cierto punto se garantice la efectividad educativa de cualquier recurso educativo es necesario comprender ¿qué es el aprendizaje?, ¿cómo ocurre? y ¿cuáles son los factores que influyen en este proceso? Y después, en función de esto, sean diseñadas las propuestas. Aunque existen muchas teorías que responden a estas preguntas desde diferentes enfoques, las Teorías de los Modelos Mentales de Johnson-Laird (1983,1996, 2013) y de los procesos cognitivos de visualización y razonamiento de Duval (1995, 1998, 1999a) han sido seleccionadas como base para la planeación y diseño de esta propuesta, pues, son teorías alternativas a las tradicionales que exploran más en la cognición humana y los procesos de aprendizaje en general y de la geometría. Los OA fueron creados completando las fases del modelo ADDIE (Análisis, Diseño, Desarrollo, Implementación y Evaluación). Durante las etapas de análisis y diseño, se planearon, siguiendo un método propuesto, las estrategias instructivas que ayudarían a la generación y comprobación de modelos mentales que representaron los temas expuestos. En el desarrollo se construyeron cada uno de los recursos y actividades para después ser empaquetados y etiquetados a través de eXeLearning (www.exelearinig.net). Después fueron implementados y evaluados. Para valorar la calidad de los OA, estos fueron valorados por expertos (desde un punto de vista pedagógico y técnico), utilizando una adaptación de la Herramienta de Evaluación de Objetos Didácticos de Aprendizaje Reutilizables (HEODAR). Los resultados reflejaron que la propuesta didáctica es de alta calidad. Por otro lado, los OA fueron implementados a un grupo de estudiantes; a través del análisis de pruebas, de las puntuaciones de la encuesta y de los comentarios recibidos, se supone que los OA tienen un buen potencial educativo como herramienta de enseñanza-aprendizaje. A través de estos análisis, se detectaron aspectos que debían ser mejorados. Entre los cuales se puede destacar la creación de una aplicación

Taming MATLAB

MATLAB is a dynamic scientific language used by scientists, engineers and students worldwide. Although MATLAB is very suitable for rapid prototyping and development, MATLAB users often want to convert their final MATLAB programs to a static language such as FORTRAN, to integrate them into already existing programs of that language, to leverage the performance of powerful static compilers, or to ease the distribution of executables. This thesis presents an extensible object-oriented toolkit to help facilitate the generation of static programs from dynamic MATLAB programs. Our open source toolkit, called the MATLAB Tamer, targets a large subset of MATLAB. Given information about the entry point of the program, the MATLAB Tamer builds a complete callgraph, transforms every function into a reduced intermediate representation, and provides typing information to aid the generation of static code. In order to provide this functionality, we need to handle a large number of MATLAB builtin functions. Part of the Tamer framework is the builtin framework, an extensible toolkit which provides a principled approach to handle a large number of builtin functions