Intelligent system for associative pattern identification in data

Mestrado em Gestão de Sistemas de InformaçãoOs resultados das ferramentas estatísticas são baseados em resultados numéricos onde a interpretação e compreensão do que está gerado passa pelo intérprete que está a analisar os resultados. Esta tarefa de compreensão é muitas vezes complicada por vários fatores sendo um dos quais o facto do intérprete não conseguir captar dos resultados o que é relevante para avaliar o modelo formulado, não conseguindo avalia-lo como válido ou não, o que poderá levar à utilização de modelos que podem ser descabidos e sem fundamento. Com esta ideia em consideração foi desenvolvido, em ambiente Linux, um pequeno sistema com técnicas de data mining de carácter associativo. Neste sistema é gerado um relatório por cada modelo, onde são analisados os fatores mais relevantes para a criação de modelos, guiando desta forma o intérprete a decidir validar e utilizar o modelo criado ou a rejeitá-lo. O objetivo deste trabalho passou pela aprendizagem da linguagem Python aplicado a dados, uma aprendizagem aprofundada sobre data mining, as técnicas e métodos existentes e uma verificação das ferramentas de machine learning, de modo a criar como produto final um sistema com algumas técnicas. Foi possível a realização do trabalho proposto com a criação do sistema. Foram formulados métodos para produzir um modelo de regressão linear múltipla, regressão logística, um modelo de correlação linear e um modelo de regras de associação. Para três modelos foram gerados métodos tendo por base bibliotecas e machine learning. Para as regras de associação foi criado um método de raiz baseado no algoritmo FP-Growth.For many people statistics is a difficult task to be done, where the output that is given from the analytic tools can be complicated to understand. With this idea it was investigated the possibility of creation of a system that provides the creation some models to the users where is provided some guidelines about the most important values to take care for each model. The goals of this project are the development of the knowledge about Data Mining, learn how to use Python to produce data analysis, verify the existent machine learning applied to data for Python and use some data mining techniques to create a small system for associative models. The system is capable to perform a Linear Regression, a Logistic Regression, a Correlation Coefficient and an Association Rule Mining algorithm. For each method is provided an output that contains the numerical results of the method and it was produce some guidelines with general ideas, assumptions of each method and it is interpreted the most important statistical values to facilitate the understanding of all the methods. The system was developed in Python. Three methods were created are based on machine learning algorithms. The association rule mining algorithm was created from the beginning. The association rule mining algorithm developed was FP-growth. The system was ready to run in Linux.info:eu-repo/semantics/publishedVersio

A new combined joules supercritical rankine cycle exergetic analysis and optimization

The application of a supercritical Rankine cycle in combined cycles does not happen in today’s thermoelectric power stations. Nevertheless, the most recent development in gas turbines, that allows a high efficiency and high exhaust gases temperatures, and the improvement of high pressure and temperature alloys, makes this cycle possible. This study’s intent is to prove the viability of this combined cycle, since it can break the 60% efficiency barrier, which is the plafond in actual power stations. To attain this target, several configurations for this cycle have been simulated, optimized and analyzed [1]. The simulations were done with the computational program IPSEpro [2] and the optimizations were effectuated with software developed for the effect, using the DFP method [3]. In parallel with the optimization that claims the cycle’s efficiency maximization, an exergetic analysis was also made [4] to all the cycle components. In opposite to what happens in subcritical combined cycles, it was demonstrated that in supercritical combined cycles the higher efficiency takes place with a single steam pressure in the heat recovery steam generator (HRSG)

Hipertensão induzida pela gravidez (Caso clínico)

A pregnant 27-year old woman, a human resources technician, with recently diagnosed high blood pres sure. She was followed by the family doctor and ob stetrician. She was sent to the Nutrition Consultation for overweight and pregnancy-induced hypertension. Blood pressure was monitored at home.Mulher de 27 anos, técnica de recursos humanos, grávida com hipertensão arterial diagnosti-cada re centemente na gravidez. É acompanhada pelo médico de família e pelo obstetra. Foi enviada à Consulta de Nutrição por excesso de peso e hipertensão induzida pela gravidez. Faz monitorização da pressão arterial no domicílioinfo:eu-repo/semantics/publishedVersio

THE ROLE OF FIRMS AND ENTREPRENEURSHIP ON LOCAL DEVELOPMENT

The present paper considers and analyzes the role of management and entrepreneurship on the firm and region sustainability. This relation was explored in terms of managers’ behaviour related to three aspects of sustainable development, namely, economic, social and environmental.Through a questionnaire survey of 251 micro, small and medium firms in Vale do Sousa region located in the Northern Portugal, it was discovered that, contrary to what most of literature presents, managers are putting in first place the environmental aspect of sustainability, followed by the social aspect, and the economic as the last one. These results lead to a characterization of firms as being sustainable, but with a risk-averse and non innovative behaviour on the part of the firms’ management.small firms, entrepreneurship, sustainability

Hydrodynamic model for a biomass grate fired system

The present paper describes a hydrodynamic model for the solids motion in a grate fired combustion system. The overfed bed material is considered in a Lagrangian referential until the particles stop in a position over the bed or exit the domain. The solid material in the grate is then considered as an incompressible continuous media. The momentum balances are applied in an Eulerian referential to particle elements to calculate their velocity in the grate direction. For the conditions considered the calculated velocity of the elements increase always from the start of the grate towards the exit, so the motion in the vertical direction is always downward. This motion is calculated from continuity and the two components enable the definition of the solids flow within the bed. The application of the model for solids motion is shown to be representative of different situations that are analysed for a vibrating grate working with wood pellets. The distribution of solids in the bed is visually and computationally characterised for three situations: i) feeding particles above the bed over an inclined still grate, ii) vibrating an initial bed promoting the motion of particles and iii) vibrating the bed and feeding above the grate in order to achieve a continuous evolution. The comparison of the results show that the model provides a good representation of reality although it can be improved by adjusting model parameters. The model allows for the generation of solids flow patterns in the bed and is a base for the development of a model for grate fired combustion systems.info:eu-repo/semantics/publishedVersio

Study of biomass particle combustion model to use in multi-particle simulation codes

This paper presents an analyses of the modelling specifications required in the simulation of the conversion of a single biomass particle to be used in multi-particles computer simulation codes. It considers the transport and reaction of gases, the heterogeneous combustion and heat transfer within the biomass. The biomass conversion is described by a competitive reaction mechanism specifying the composition of the volatile species and tar properties. This approach can represent the influence of the heating conditions on biomass conversion and produce acceptable compositions for the final products. Tar decomposition is considered within the particle as well as combustion reactions for all combustibles: volatile, tar and char. The study of several approaches show the level of numerical approach required to simulate the thermal conversion of the biomass particle and further reactions such as tar decomposition and oxidation of the combustibles gases within the particle. The validation of the numerical code is accomplished with the conversion of a 50 mm trunk in a hot gas stream by measuring the mass loss and temperature along the combustion process. Parametric tests are carried out to investigate the conversion of tars and oxidation of gases within the particle and it is concluded that these can be neglected for particle diameters smaller than 20 mm with an error less than 1%. For combustible particles such as wood chips and pellets with 6 mm diameter, all intern gradients may be neglected.info:eu-repo/semantics/publishedVersio

Modeling biomass particle drying, devolatilization and combustion in a grate fired combustor

The paper presents the application of a numerical model to describe the evolution of a particle in a grate fired combustion system. Due to the particle dimensions, important temperature gradients exist inside the particles and reactions occur within the particles. A model using layers is used to describe the processes inside the particles. The biomass composition is expressed as fractions of moisture, unreacted biomass, char and ash. Biomass conversion is described by a competitive reaction model leading to the formation of light volatiles, tars and char. Tar is subject of secondary reactions inside the particles forming either light gases or char. Transport equations are solved for the gases within the particle including oxygen from the environment that reacts with gases or char. The model is applied to different heating rates leading to different amounts of tars and char in accordance with data from the literature. The model is also applied to simulate the combustion of a single trunk standing in a heated gas stream and comparisons are done for the temperature and mass loss.info:eu-repo/semantics/publishedVersio

Do "small is beautiful" ao "small is unsustainable"

O presente artigo debruça-se sobre a realidade das actividades económicas de pequena escala em Portugal. as discussões políticas mais recentes têm vindo a colocar “em cima da mesa”, cada vez com maior insistência, a problemática das pequenas e médias empresas. No entanto, como não se ultrapassam as abordagens generalistas, a especificidade das unidades económicas de pequena escala não emerge, sendo por essa via invisibilizada ao nível do pensamento e da acção. Ao longo das próximas páginas serão abordadas as dificuldades enfrentadas por estes microempreendedores, obrigados a respeitar quadros normativos e procedimentos funcionais estipulados para regular a competitividade internacional, mesmo que o seu campo de acção sejam os mercados de proximidade. São os reflexos de um país com “sede” de internacionalização, preocupado com as exportações e o investimento estrangeiro, mas que ao mesmo tempo cilindra as pequenas unidades produtivas nacionais que garantem emprego e produção de riqueza, conduzindo o país a uma dinâmica de empobrecimento

Caracterização energética e segurança na utilização de recuperadores de calor para lareiras

Os recuperadores de calor para lareiras são dispositivos de aquecimento doméstico cuja utilização está em expansão. A sua correcta utilização, quer no que respeita à segurança quer ao desempenho energético requer a caracterização destes equipamentos. Desta necessidade nasceu o projecto RECUPERA realizado em parceria entre a EST–ADEM da Universidade do Algarve e a empresa Vale–Montanha L.da., fabricante destes equipamentos. Foram realizados ensaios segundo a norma europeia em vigor EN 13299:2001 dos quais se obteve a distribuição de temperaturas nos recuperadores e envolvente, potência média, carga de lenha recomendada, emissões de CO e rendimento térmico. O presente artigo tem por objectivo apresentar os resultados obtidos nos ensaios, descrevendo a metodologia seguida e comparando os custos de operação entre vários equipamentos de aquecimento doméstico alternativos

Monitoring of physical activity levels of guide dog owners – a preliminary study

Despite the well-documented benefits of regular physical activity, people with disabilities are often challenged with too many barriers that discourage an active lifestyle. This is particularly evident among people with visual impairments (VI). Previous studies have shown that adults with VI are significantly less active than the general population, and do not meet the physical activity recommendations of the World Health Organisation (WHO). However, most study samples are based on participants using a white cane. Owning a guide dog is often described as a factor for increased mobility and has the potential to increase physical activity. Therefore, the purpose of this preliminary study was to objectively assess the physical activity of adults with VI assisted by a guide dog