An automated approach for performance deviation analysis of evolving software systems

A manutenção e evolução de sistemas de software tornou-se uma tarefa bastante crítica ao longo dos últimos anos devido à diversidade e alta demanda de funcionalidades, dispositivos e usuários. Entender e analisar como novas mudanças impactam os atributos de qualidade da arquitetura de tais sistemas é um pré-requisito essencial para evitar a deterioração de sua qualidade durante sua evolução. Esta tese propõe uma abordagem automatizada para a análise de variação do atributo de qualidade de desempenho em termos de tempo de execução (tempo de resposta). Ela é implementada por um framework que adota técnicas de análise dinâmica e mineração de repositório de software para fornecer uma forma automatizada de revelar fontes potenciais – commits e issues – de variação de desempenho em cenários durante a evolução de sistemas de software. A abordagem define quatro fases: (i) preparação – escolher os cenários e preparar os releases alvos; (ii) análise dinâmica – determinar o desempenho de cenários e métodos calculando seus tempos de execução; (iii) análise de variação – processar e comparar os resultados da análise dinâmica para releases diferentes; e (iv) mineração de repositório – identificar issues e commits associados com a variação de desempenho detectada. Estudos empíricos foram realizados para avaliar a abordagem de diferentes perspectivas. Um estudo exploratório analisou a viabilidade de se aplicar a abordagem em sistemas de diferentes domínios para identificar automaticamente elementos de código fonte com variação de desempenho e as mudanças que afetaram tais elementos durante uma evolução. Esse estudo analisou três sistemas: (i) SIGAA – um sistema web para gerência acadêmica; (ii) ArgoUML – uma ferramenta de modelagem UML; e (iii) Netty – um framework para aplicações de rede. Outro estudo realizou uma análise evolucionária ao aplicar a abordagem em múltiplos releases do Netty, e dos frameworks web Wicket e Jetty. Nesse estudo foram analisados 21 releases (sete de cada sistema), totalizando 57 cenários. Em resumo, foram encontrados 14 cenários com variação significante de desempenho para Netty, 13 para Wicket e 9 para Jetty. Adicionalmente, foi obtido feedback de oito desenvolvedores desses sistemas através de um formulário online. Finalmente, no último estudo, um modelo de regressão para desempenho foi desenvolvido visando indicar propriedades de commits que são mais prováveis a causar degradação de desempenho. No geral, 997 commits foram minerados, sendo 103 recuperados de elementos de código fonte degradados e 19 de otimizados, enquanto 875 não tiveram impacto no tempo de execução. O número de dias antes de disponibilizar o release e o dia da semana se mostraram como as variáveis mais relevantes dos commits que degradam desempenho no nosso modelo. A área de característica de operação do receptor (ROC – Receiver Operating Characteristic) do modelo de regressão é 60%, o que significa que usar o modelo para decidir se um commit causará degradação ou não é 10% melhor do que uma decisão aleatória.

An automated approach for performance deviation analysis of evolving software systems

A manutenção e evolução de sistemas de software tornou-se uma tarefa bastante crítica ao longo dos últimos anos devido à diversidade e alta demanda de funcionalidades, dispositivos e usuários. Entender e analisar como novas mudanças impactam os atributos de qualidade da arquitetura de tais sistemas é um pré-requisito essencial para evitar a deterioração de sua qualidade durante sua evolução. Esta tese propõe uma abordagem automatizada para a análise de variação do atributo de qualidade de desempenho em termos de tempo de execução (tempo de resposta). Ela é implementada por um framework que adota técnicas de análise dinâmica e mineração de repositório de software para fornecer uma forma automatizada de revelar fontes potenciais – commits e issues – de variação de desempenho em cenários durante a evolução de sistemas de software. A abordagem define quatro fases: (i) preparação – escolher os cenários e preparar os releases alvos; (ii) análise dinâmica – determinar o desempenho de cenários e métodos calculando seus tempos de execução; (iii) análise de variação – processar e comparar os resultados da análise dinâmica para releases diferentes; e (iv) mineração de repositório – identificar issues e commits associados com a variação de desempenho detectada. Estudos empíricos foram realizados para avaliar a abordagem de diferentes perspectivas. Um estudo exploratório analisou a viabilidade de se aplicar a abordagem em sistemas de diferentes domínios para identificar automaticamente elementos de código fonte com variação de desempenho e as mudanças que afetaram tais elementos durante uma evolução. Esse estudo analisou três sistemas: (i) SIGAA – um sistema web para gerência acadêmica; (ii) ArgoUML – uma ferramenta de modelagem UML; e (iii) Netty – um framework para aplicações de rede. Outro estudo realizou uma análise evolucionária ao aplicar a abordagem em múltiplos releases do Netty, e dos frameworks web Wicket e Jetty. Nesse estudo foram analisados 21 releases (sete de cada sistema), totalizando 57 cenários. Em resumo, foram encontrados 14 cenários com variação significante de desempenho para Netty, 13 para Wicket e 9 para Jetty. Adicionalmente, foi obtido feedback de oito desenvolvedores desses sistemas através de um formulário online. Finalmente, no último estudo, um modelo de regressão para desempenho foi desenvolvido visando indicar propriedades de commits que são mais prováveis a causar degradação de desempenho. No geral, 997 commits foram minerados, sendo 103 recuperados de elementos de código fonte degradados e 19 de otimizados, enquanto 875 não tiveram impacto no tempo de execução. O número de dias antes de disponibilizar o release e o dia da semana se mostraram como as variáveis mais relevantes dos commits que degradam desempenho no nosso modelo. A área de característica de operação do receptor (ROC – Receiver Operating Characteristic) do modelo de regressão é 60%, o que significa que usar o modelo para decidir se um commit causará degradação ou não é 10% melhor do que uma decisão aleatória.

Efeito Da Suplementação Materna Com Palmitato De Retinila Sobre A Concentração De Retinol No Colostro Em Condições De Jejum E Pós-Prandial.

Vitamin A is important in many essential body processes and its deficiency results in serious consequences for human health. Breast milk is the only source of this vitamin for children that are exclusively breastfed. Analysis of vitamin A in mother s milk is important because its concentration is related to maternal vitamin A status and to its ingestion by the mother during pregnancy. The aim of the present study was to assess the effect of maternal supplementation with retynil palmitate on the concentration of colostrum retinol under fasting and postprandial conditions. A total of 149 nursing mothers were recruited at the Januário Cicco Maternity School (Natal, Brazil) and allocated to two groups: Comparison (n = 69) and Test (n = 80). Blood and colostrum (in fasting and postprandial conditions) samples were collected up to 24hs after delivery. Serum retinol and colostrum levels were analyzed by high-performance liquid chromatography. The serum retinol level of 41.6 ± 12.7μg/dL (mean ± standard deviation) indicates adequate biochemical nutritional status. Colostrum retinol level was not influenced by serum retinol levels under any of the conditions established. In the colostrum, the retinol concentration in the unsupplemented test group was 67.3 ± 37.7 μg/dL under fasting and 80.3 ± 35.1 μg/dL under postprandial conditions (p<0.05), showing an increase of 19.3%. In the supplemented test group the values were 102.6 ± 57.3 μg/dL and 133.4 ± 78.3 μg/dL under fasting and postprandial, respectively (p<0.05), representing an increase of 30%. Considering that under fasting conditions most of the vitamin A transported to the milk originates in the retinol binding protein (RBP), the postprandial increase in colostrum retinol suggests a different transport mechanism of retinol to maternal milk from that performed by RBP. This situation becomes more evident under supplementation conditions.

Efeito do estado nutricional bioquímico de retinol e alfatocoferol sobre seus níveis em lactantes

Vitamins A and E are essential nutrients in many biological processes, so that their adequate supply to the neonate is crucial. However, the bioavailability of vitamins may be limited by factors such as maternal nutritional status and the interaction between nutrients. This study aimed to investigate the effect of biochemical nutritional status of retinol and alpha-tocopherol levels in serum and colostrum. The study included 103 healthy puerperal women treated at the reference state maternity hospital (Natal-RN). Colostrum and serum samples were collected fasting in the immediate postpartum period and the analysis of retinol and alpha-tocopherol were determined by high-performance liquid chromatography. Specific cutoff points were adopted to characterize the biochemical status of vitamins A and E. For the total group of lactanting women the average concentration of retinol in serum (1.49 ± 0.4 μmol/L-1) and colostrum (2.18 ± 0.8 μmol/L-1), as well as alpha-tocopherol in serum (26.4 ± 8.0 μmol/L-1) and colostrum (26.1 ± 12.8 μmol/L-1), indicated adequate biochemical state. However, when evaluating the individual, was found a high prevalence of deficient serum (15%) and colostrum retinol (50%), and also alphatocopherol in serum (16%) and colostrum (61%). In women with serum retinol ≥ 1.05 μmol/L-1, found an inverse correlation between serum retinol and alpha-tocopherol in colostrum (p = 0.008, r = -0.28). This association was not observed in women with serum retinol <1.05 μmol/L-1. This situation demonstrates for the first time in humans that high physiological levels of serum retinol, without supplementation, can negatively influence the transfer of alpha-tocopherol in breast milk. Although the diagnosis of satisfactory nutritional status lactanting women showed high risk of subclinical deficiency of vitamins A and E from measurements made in the colostrum

Avaliação do retinol em parturientes com diabetes mellitus gestacional no pós parto imediato

Micronutrient deficiencies affect individuals mainly in developing countries, where vitamin A deficiency is a public health problem worldwide more worrying, especially in groups with increased physiological needs such as children and women of reproductive age. Vitamin A is supplied to the body through diet and has an important role in the visual process, cell differentiation, maintenance of epithelial tissue, reproductive and resistance to infection. The literature has demonstrated the relationship between vitamin A and diabetes, including gestational, leading to a risk to both mother and child. Gestational diabetes is any decrease in glucose tolerance of variable magnitude diagnosed each the first time during pregnancy, and may or may not persist after delivery. Insulin resistance during pregnancy is associated with placental hormones, as well as excess fat. Studies have shown that retinol transport protein produced in adipose tissue in high concentrations, this would be associated with resistance by interfering with insulin signaling. Therefore, this study aimed to evaluate the concentration of retinol in serum and colostrum from healthy and diabetic mothers in the immediate postpartum period. One hundred and nine parturient women were recruited, representing seventy-three healthy and thirty-six diabetic. Retinol was extracted and subsequently analyzed by High Performance Liquid Chromatography. Among the results highlights the mothers with gestational diabetes were older than mothers healthy, had more children and a higher prevalence of cases of cesarean section. Fetal macrosomia was present in 1.4% of healthy parturient women and in 22.2% of diabetic mothers. The maternal serum retinol showed an average of 39.7 ± 12.5 mg/dL for healthy parturients 35.12 ± 15 mg/dL for diabetic and showed no statistical difference. It was observed that in the group of diabetic had 17% vitamin A deficiency, whereas in the healthy group, only 4% of the women were deficentes. Colostrum, the concentration of retinol in healthy was 131.3 ± 56.2 mg/dL and 125.3 ± 41.9 mg/dL in diabetic did not differ statistically. This concentration of retinol found in colostrum provides approximately 656.5 mg/day for infants born to healthy mothers and 626.5 mg/day for infants of diabetic mothers, based on a daily consumption of 500 mL of breast milk and need Vitamin A 400 mg/day, thus reaching the requirement of the infant. The diabetic mothers showed significant risk factors and complications related to gestational diabetes. Although no 11 difference was found in serum retinol concentration and colostrum among women with and without gestational diabetes, the individual analysis shows that parturients women with diabetes are 4.9 times more likely to develop vitamin A deficiency than healthy parturients. However, the supply of vitamin A to the newborn was not committed in the presence of gestational diabetes

Mesoestruturas porosas a partir de materiais naturais

The MCM-41 mesoporous synthesis was done using rice hulls ash and chrysotile as natural alternative silica sources. For the using of these sources, chemical and thermic treatments were done in both materials. After chemical and thermic treatments, these materials were employed on the MCM-41 mesoctructures synthesis. The natural materials treated and employed in the synthesis were characterized by several techniques such as X-ray diffraction, N2 adsorption and desorption, scanning electronic microscopy and thermogravimetric analysis. MCM-41 standart samples synthetized with aerosil 200 commercial sílica were used to evaluation. The formed material from rice hulls ash showed values from BET specific area about 468 m².g-1, N2 adsorption and desorption isotherms and loss mass similar to reference materials. The silica from chrysotile calcined and leached was employed to mesoporous materials synthesis. The BET specific area showed values about 700 m².g-1, N2 adsorption and desorption isotherms type IV and loss mass similar to mesoporous materials. The formed material from calcined and leached chrysotile, without calcination, applied to phenol remotion carried high performance liquid chromatography and evaluated with organophilic clays with different treatments. By the characterization techniques were proved that mesoporous materials with lesser order that reference samples. The material formed from rice hulls ash without the calcination step achieved better adsorption results than organophilic clays

Propriedade fotoluminescente da ZrO2: Tb+3, Eu+3, Tm+3 obtida pelo método de polimerização de complexos

Recent studies are investigating a new class of inorganic materials which arise as a promising option for high performance applications in the field of photoluminescence. Highlight for rare earth (TR +3 ) doped, which have a high luminous efficiency, long decay time and being able to emit radiation in the visible range, specific to each element. In this study, we synthesized ZrO2: Tb +3 , Eu +3 , Tm +3 nanoparticles complex polymerization method (CPM). We investigated the influences caused by the heat treatment temperature and the content of dopants in zirconia photoluminescent behavior. The particles were calcined at temperature of 400, 500 and 600 ° C for two hours and ranged in concentration of dopants 1, 2, 4 and 8 mol% TR +3 . The samples were characterized by thermal analysis, X-ray diffraction, photoluminescence of measurements and uv-visible of spectroscopies. The results of X-ray diffraction confirmed the formation of the tetragonal and cubic phases in accordance with the content of dopants. The photoluminescence spectra show emission in the region corresponding simultaneous to blue (450 nm), green (550 nm) and red (615 nm). According to the results, ZrO2 particles co-doped with rare earth ions is a promising material white emission with a potential application in the field of photoluminescence

Plásticos reforçados a base de tecidos híbridos: efeitos da anisotropia e geometria normativa na caracterização mecânica e da fratura

As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy

Caracterização e quantificação de marcadores químicos do extrato hidroetanólico das folhas de Kalanchoe brasiliensis Cambess

Kalanchoe brasiliensis Cambess (Crassulaceae), commonly known as saião , coirama branca , folha grossa , is originally from Brazil and commonly found in São Paulo to Bahia, mainly in the coastal zone. Regarding of biological activities, most preclinical studies were found in the literature, mainly about the anti-inflammatory activity of extracts obtained from leaves and / or aerial parts of K. brasiliensis. As regards the chemical constitution, it has been reported mainly the presence of flavonoids in the leaves of the species, but until this moment did not knows which are the active compounds. Although it is a species widely used in traditional medicine in Brazil, there is no monograph about the quality parameters of the plant drug. In this context, this study aims to characterize and quantify the chemical markers of hydroethanolic extract (HE) from the leaves of K. brasiliensis, which can be used in quality control of plant drug and derivatives obtained from this species. The methodology was divided into two parts: i. Phytochemical study: to fractionate, isolate and characterizate of the chemical (s) marker (s) of the HE from the leaves of K. brasiliensis; ii. To Developed validate of analytical method by High Performance Liquid Chromatography (HPLC)-diode array detector (DAD) to quantify the chemical (s) marker (s) of the EH. i. The EH 50% was prepared by turbo extraction method. It was then submitted to liquid-liquid partition, obtaining dichloromethane, n-butanol and ethyl acetate (AcOEt) fractions. The AcOEt fraction was selected to continue the fractionation process, because it has a chemical profile rich in flavonoids. The acOEt fraction was submitted to column chromatography using different systems for obtaining the compound Kb1. To identify this compound, it was submitted to UV analysis ii. For quantitative analysis, the EH was analyzed by HPLC, using different methods. After selecting the most appropriate method, which showed satisfactory resolution and symmetrical peaks, it was validated according to parameters in the RE 899/2003. As result, it was obtained from the AcOEt fraction the compound Kb1 (2.7 mg). Until this moment, the basic nucleus was characterized by UV analysis using shift reagents. The partial chemical structure of the compound Kb1 was identified as a flavonol, containing hydroxyls in 3 , 4 position (ring A), 5 and 7 free (ring B) and a replacement of the C3 hydroxyl by a sugar. As the analysis were performed in the HPLC coupled to a DAD, we observed that the UV spectrum of the major peaks of EH from K. brasiliensis shown similar UV spectrum. According to the literature, it has been reported the presence of patuletin glycosydes derivatives in the leaves of this species. Therefore, it is suggested that the compound Kb1 is glycosylated patuletin derivative. Probably the sugar (s) unit(s) are linked in the C3 in the C ring. . Regarding the development of HPLC analytical method, the system used consists of phase A: water: formic acid (99,7:0,3, v / v) and phase B: methanol: formic acid (99,7:0,3, v / v), elution gradient of 40% B - 58% B in 50 minutes, ccolumn (Hichrom ®) C18 (250x4, 0 mm, 5 μm), flow rate 0.8 mL / min, UV detection at 370 nm, temperature 25 ° C. In the analysis performed with the co-injection of thecompound Kb1 + HE of K. brasiliensis was observed that it is one of the major compounds with a retention time of 12.47 minutes and had a content of 15.3% in EH of leaves from K. brasiliensis. The method proved to be linear, precise, accurate and reproducible. According to these results, it was observed that compound Kb1 can be used as a chemical marker of EH from leaves of K. brasiliensis, to assist in quality control of drug plant and its derivatives

Otimização evalidação de métodos analíticos para a determinação simultânea de tuberculostáticos (4-FDC) por CLAE/DAD e CLUE/ DAD

Tuberculosis is a serious disease, but curable in practically 100% of new cases, since complied the principles of modern chemotherapy. Isoniazid (ISN), Rifampicin (RIF), Pyrazinamide (PYR) and Chloride Ethambutol (ETA) are considered first line drugs in the treatment of tuberculosis, by combining the highest level of efficiency with acceptable degree of toxicity. Concerning USP 33 - NF28 (2010) the chromatography analysis to 3 of 4 drugs (ISN, PYR and RIF) last in average 15 minutes and 10 minutes more to obtain the 4th drug (ETA) using a column and mobile phase mixture different, becoming its industrial application unfavorable. Thus, many studies have being carried out to minimize this problem. An alternative would use the UFLC, which is based with the same principles of HPLC, however it uses stationary phases with particles smaller than 2 μm. Therefore, this study goals to develop and validate new analytical methods to determine simultaneously the drugs by HPLC/DAD and UFLC/DAD. For this, a analytical screening was carried out, which verified that is necessary a gradient of mobile phase system A (acetate buffer:methanol 94:6 v/v) and B (acetate buffer:acetonitrile 55:45 v/v). Furthermore, to the development and optimization of the method in HPLC and UFLC, with achievement of the values of system suitability into the criteria limits required for both techniques, the validations have began. Standard solutions and tablets test solutions were prepared and injected into HPLC and UFLC, containing 0.008 mg/mL ISN, 0.043 mg/mL PYR, 0.030 mg.mL-1 ETA and 0.016 mg/mL RIF. The validation of analytical methods for HPLC and UFLC was carried out with the determination of specificity/selectivity, analytical curve, linearity, precision, limits of detection and quantification, accuracy and robustness. The methods were adequate for determination of 4 drugs separately without interfered with the others. Precise, due to the fact of the methods demonstrated since with the days variation, besides the repeatability, the values were into the level required by the regular agency. Linear (R> 0,99), once the methods were capable to demonstrate results directly proportional to the concentration of the analyte sample, within of specified range. Accurate, once the methods were capable to present values of variation coefficient and recovery percentage into the required limits (98 to 102%). The methods showed LOD and LOQ very low showing the high sensitivity of the methods for the four drugs. The robustness of the methods were evaluate, facing the temperature and flow changes, where they showed robustness just with the preview conditions established of temperature and flow, abrupt changes may influence with the results of methods

Desenvolvimento e validação de método analítico para determinação de WE010, WE014 e WE017

The synthetic guanylhydrazones WE010 (3,5-di-tert-butil-4-hidroxibenzaldehyde-guanylhydrazone), WE014 (4-bifenilcarboxialdehydeguanylhydrazone) and WE017 (3,4-diclorobenzaldehydeguanylhydrazone) showed high cytotoxic activity in terms of percentage inhibition of cancer cells growth. However, further progress in the development of these drug candidates requires precise and convenient methods for their qualitative and quantitative analyses. The aim of this study was to develop and validate High Performance Liquid Chromatography with diode-array detection (HPLC-DAD) and Ultra Fast Liquid Chromatography with diode-array detection (UFLC-DAD) methods suitable for as simultaneous as isolated determination of studied guanylhydrazones, based on the optimization of chromatographic parameters and obtaining reduced detection times. The chromatographic analyses of analytes by HPLC were performed on C18 ACE analytical column (150 mm x 4.6 mm), with a particle size of 5.0 μm. Among all the conditions assayed, the best results of separation were obtained with a mixture of methanol:water (60:40, v/v) as the mobile phase at a flow rate 1.5mL/min and pH of 3.5 adjusted at acetic acid. The UFLC method was developed by experimetal desing techniques in order to find optimal chromatographic analytical conditions, which were achieved on XR-ODS analytical column (50 mm x 3.0 mm), with a particle size of 2,2 μm, maintained at 25 ºC. The mobile phase was consisted of methanol:water (65:35, v/v) with 0.1% triethylamine (TEA) and pH of 3.5 adjusted at acetic acid, at a flow rate 0.5 mL/min. The procedure were validated following evaluating parameters such as specificity, linearity, limits of detection (LD) and quantification (LQ), precision, accuracy and robustness, giving results within the acceptable range. Although the UFLC method shows better sensitivity (lower values of LD and LQ), robustness (lower rates of relative standard deviation) and minimize spending time and solvent, both developed methods were adequately applied to the analysis of guanylhydrazones molecules, may be used in routine of quality control laboratories. Keywords: guanylhydrazones, HPLC/DAD, UFLC/DAD, validation of analitical method

Análise e otimização de superfícies seletivas de Frequência utilizando redes neurais artificiais e algoritmos de otimização natural

The bidimensional periodic structures called frequency selective surfaces have been well investigated because of their filtering properties. Similar to the filters that work at the traditional radiofrequency band, such structures can behave as band-stop or pass-band filters, depending on the elements of the array (patch or aperture, respectively) and can be used for a variety of applications, such as: radomes, dichroic reflectors, waveguide filters, artificial magnetic conductors, microwave absorbers etc. To provide high-performance filtering properties at microwave bands, electromagnetic engineers have investigated various types of periodic structures: reconfigurable frequency selective screens, multilayered selective filters, as well as periodic arrays printed on anisotropic dielectric substrates and composed by fractal elements. In general, there is no closed form solution directly from a given desired frequency response to a corresponding device; thus, the analysis of its scattering characteristics requires the application of rigorous full-wave techniques. Besides that, due to the computational complexity of using a full-wave simulator to evaluate the frequency selective surface scattering variables, many electromagnetic engineers still use trial-and-error process until to achieve a given design criterion. As this procedure is very laborious and human dependent, optimization techniques are required to design practical periodic structures with desired filter specifications. Some authors have been employed neural networks and natural optimization algorithms, such as the genetic algorithms and the particle swarm optimization for the frequency selective surface design and optimization. This work has as objective the accomplishment of a rigorous study about the electromagnetic behavior of the periodic structures, enabling the design of efficient devices applied to microwave band. For this, artificial neural networks are used together with natural optimization techniques, allowing the accurate and efficient investigation of various types of frequency selective surfaces, in a simple and fast manner, becoming a powerful tool for the design and optimization of such structures

Uma implementação da análise de componentes independentes em plataforma de hardware reconfigurável

Blind Source Separation (BSS) refers to the problem of estimate original signals from observed linear mixtures with no knowledge about the sources or the mixing process. Independent Component Analysis (ICA) is a technique mainly applied to BSS problem and from the algorithms that implement this technique, FastICA is a high performance iterative algorithm of low computacional cost that uses nongaussianity measures based on high order statistics to estimate the original sources. The great number of applications where ICA has been found useful reects the need of the implementation of this technique in hardware and the natural paralelism of FastICA favors the implementation of this algorithm on digital hardware. This work proposes the implementation of FastICA on a reconfigurable hardware platform for the viability of it's use in blind source separation problems, more specifically in a hardware prototype embedded in a Field Programmable Gate Array (FPGA) board for the monitoring of beds in hospital environments. The implementations will be carried out by Simulink models and it's synthesizing will be done through the DSP Builder software from Altera Corporation.

Estudos de algumas ferramentas de coleta e visualização de dados e desempenho de aplicações paralelas no ambiente MPI

The last years have presented an increase in the acceptance and adoption of the parallel processing, as much for scientific computation of high performance as for applications of general intention. This acceptance has been favored mainly for the development of environments with massive parallel processing (MPP - Massively Parallel Processing) and of the distributed computation. A common point between distributed systems and MPPs architectures is the notion of message exchange, that allows the communication between processes. An environment of message exchange consists basically of a communication library that, acting as an extension of the programming languages that allow to the elaboration of applications parallel, such as C, C++ and Fortran. In the development of applications parallel, a basic aspect is on to the analysis of performance of the same ones. Several can be the metric ones used in this analysis: time of execution, efficiency in the use of the processing elements, scalability of the application with respect to the increase in the number of processors or to the increase of the instance of the treat problem. The establishment of models or mechanisms that allow this analysis can be a task sufficiently complicated considering parameters and involved degrees of freedom in the implementation of the parallel application. An joined alternative has been the use of collection tools and visualization of performance data, that allow the user to identify to points of strangulation and sources of inefficiency in an application. For an efficient visualization one becomes necessary to identify and to collect given relative to the execution of the application, stage this called instrumentation. In this work it is presented, initially, a study of the main techniques used in the collection of the performance data, and after that a detailed analysis of the main available tools is made that can be used in architectures parallel of the type to cluster Beowulf with Linux on X86 platform being used libraries of communication based in applications MPI - Message Passing Interface, such as LAM and MPICH. This analysis is validated on applications parallel bars that deal with the problems of the training of neural nets of the type perceptrons using retro-propagation. The gotten conclusions show to the potentiality and easinesses of the analyzed tools.

Arquiteturas eficientes para sensoriamento espectral e classificação automática de modulações usando características cicloestacionárias

The increasing demand for high performance wireless communication systems has shown the inefficiency of the current model of fixed allocation of the radio spectrum. In this context, cognitive radio appears as a more efficient alternative, by providing opportunistic spectrum access, with the maximum bandwidth possible. To ensure these requirements, it is necessary that the transmitter identify opportunities for transmission and the receiver recognizes the parameters defined for the communication signal. The techniques that use cyclostationary analysis can be applied to problems in either spectrum sensing and modulation classification, even in low signal-to-noise ratio (SNR) environments. However, despite the robustness, one of the main disadvantages of cyclostationarity is the high computational cost for calculating its functions. This work proposes efficient architectures for obtaining cyclostationary features to be employed in either spectrum sensing and automatic modulation classification (AMC). In the context of spectrum sensing, a parallelized algorithm for extracting cyclostationary features of communication signals is presented. The performance of this features extractor parallelization is evaluated by speedup and parallel eficiency metrics. The architecture for spectrum sensing is analyzed for several configuration of false alarm probability, SNR levels and observation time for BPSK and QPSK modulations. In the context of AMC, the reduced alpha-profile is proposed as as a cyclostationary signature calculated for a reduced cyclic frequencies set. This signature is validated by a modulation classification architecture based on pattern matching. The architecture for AMC is investigated for correct classification rates of AM, BPSK, QPSK, MSK and FSK modulations, considering several scenarios of observation length and SNR levels. The numerical results of performance obtained in this work show the eficiency of the proposed architectures