27 resultados para One-Way Function (OWF)


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The composition of petroleum may change from well to well and its resulting characteristics influence significantly the refine products. Therefore, it is important to characterize the oil in order to know its properties and send it adequately for processing. Since petroleum is a multicomponent mixture, the use of synthetic mixtures that are representative of oil fractions provides a better understand of the real mixture behavior. One way for characterization is usually obtained through correlation of physico-chemical properties of easy measurement, such as density, specific gravity, viscosity, and refractive index. In this work new measurements were obtained for density, specific gravity, viscosity, and refractive index of the following binary mixtures: n-heptane + hexadecane, cyclohexane + hexadecane, and benzene + hexadecane. These measurements were accomplished at low pressure and temperatures in the range 288.15 K to 310.95 K. These data were applied in the development of a new method of oil characterization. Furthermore, a series of measurements of density at high pressure and temperature of the binary mixture cyclohexane + n-hexadecane were performed. The ranges of pressure and temperature were 6.895 to 62.053 MPa and 318.15 to 413.15 K, respectively. Based on these experimental data of compressed liquid mixtures, a thermodynamic modeling was proposed using the Peng-Robinson equation of state (EOS). The EOS was modified with scaling of volume and a relatively reduced number of parameters were employed. The results were satisfactory demonstrating accuracy not only for density data, but also for isobaric thermal expansion and isothermal compressibility coefficients. This thesis aims to contribute in a scientific manner to the technological problem of refining heavy fractions of oil. This problem was treated in two steps, i.e., characterization and search of the processes that can produce streams with economical interest, such as solvent extraction at high pressure and temperature. In order to determine phase equilibrium data in these conditions, conceptual projects of two new experimental apparatus were developed. These devices consist of cells of variable volume together with a analytical static device. Therefore, this thesis contributed with the subject of characterization of hydrocarbons mixtures and with development of equilibrium cells operating at high pressure and temperature. These contributions are focused on the technological problem of refining heavy oil fractions

Relevância:

100.00% 100.00%

Publicador:

Resumo:

To analyze the effects of electrical stimulation at two frequencies on the EMG parameters (EMG) and dynamometer, in muscles with different typing. MATERIALS AND METHODS: This is a controlled clinical trial, randomized and double blind. Sixty healthy volunteers (23.6 ± 4.2anos; 54.2 ± 7.7kg, 1.62 ± 0.009 cm) of both sexes were divided randomly into three groups: control group (CG), experimental group 1 (SG1) with application of the current Russian 30 HZ and experimental group 2 (EG2) at 70 Hz The volunteers performed an initial assessment (AV1) on the isokinetic dynamometer with three repetitions maximum voluntary isometric (MVC) for knee extension concomitant uptake of EMG for the VM muscle, VL and RF. Later, after application of NMES, they underwent an experimental protocol of isometric fatigue using 70% of MVIC, ending with the completion of a final assessment (AV2) in the same manner as the AV1. RESULTS: By analyzing the profile of the 60 subjects in three broad, VM showed a higher value of RMS behavior when the VL and RF (p = 0.03 and p = 0.02). With respect to Fmed the RF muscle (p = 0.001) showed a higher value for the VM. The VM muscle showed significant increases of Fmed (p = 0.05) after electrical stimulation at 70 Hz when compared the AV1 AV2 and RF showed significant decreases (p = 0.009) after stimulation at 30 Hz during the fatigue showed an increase RMS in the VM and VL, with a reduction in RF. For the variable Fmed was observed in three broad decline during fatigue. CONCLUSION: Our findings provide evidence that the muscles VM, VL and RF fiber typing are different besides indicating that the frequency of NMES tend to relate to the muscle stimulated. Finally suggests the surface EMG as a noninvasive method for characterizing muscle

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Introduction: The aging process causes quantitative and qualitative changes in sleeping. Such changes affects more than half of the adults above 65 years old, that live in the community and 70% of the institutionalized, a great negative impact in their quality of life. One of the pathological displays of aging, that share some characteristics with sleeping disorders and predict similar results, is the Frailty Syndrome, that characterize the most weakened and vulnerable elderly. The way sleeping disorders play a role in the frailty pathogeneses remains uncertain. Objective: Evaluate the relation between the sleeping and the frailty syndrome on institutionalized elderly. Methodology: A transversal study was performed with 69 elderly in institutions in the city of João Pessoa PB. Were used the Pittsburgh Sleeping Quality Index and actigraphy to subjective and objective variables, respectively, and questionnaires and specific tests to frailty phenotype variant (Fried Frailty Criteria). In the statistic analysis were used the Pearson correlation test, Chi Square and One-way ANOVA test, with Tukey-Krammer posttest. Subsequently, a Simple Linear Regression model was built. On every statistical analysis were considered a confidence interval of 95% and a p < 0,05. Results: The sample was characterized by the prevalence of the frail (49,3%), women (62,3%), single (50,7%) and 77,52 (±7,82).The frail elderly obtained the worst sleeping quality 10,37 (±4,31) (f = 4,15, p = 0,02), when compared with the non-frail. The sleep latency influenced more the frailty (R2 = 0,13, β standard = 1,76, β = 0,41, p = 0,001). Weren t found differences between the standard resting-activity variable and the frailty phenotype categories. Conclusion: Sleeping alterations, including bad sleeping quality, prolonged sleep latency, low sleep efficiency and day drowsiness, influenced the frailty in institutionalized elderly

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Introduction: The reference values and prediction equations for maximal respiratory pressures (MRP) differ significantly between the available studies. This large discrepancy can be attributed to the different methodologies proposed. Although the importance of MRP is widely recognized, there are no Brazilian studies that provide predictive equations and reference values for PRM adolescents. Objectives: The purpose of this study was to provide normal values and propose predictive equations for maximal static respiratory pressures of Brazilian adolescents. Methods: An observational cross-sectional study, which evaluated 182 adolescents of both sexes aged between 12 and 18 years, enrolled in schools of the state and private in the city of Natal / RN. The selection of schools and participants of the study was randomly through a lottery system. The spirometric evaluation was performed through the digital spirometer One Flow FVC prior to the assessment of respiratory muscle strength. The MICs were measured with MVD digital manometer 300. Statistical analysis was performed using the SPSS 17.0 software STATISTICS, assigning the significance level of 5%. The normality of data distribution was verified using the Kolmogorov-Smirnov (KS). The descriptive analysis was expressed as mean and standard deviation. We used one-way ANOVA test to verify the difference of the averages of MRPs between age and gender and comparing the averages of MRPs between levels of physical activity. The test t'Student unpaired compared the averages of MRPs being ages and sexes. The comparison of mean values obtained in this study PRM with the values predicted using the equations mentioned above was relizada by testing paired t'Student. To verify the correlation between the PRM and the independent variables (age, weight, height) was used Pearson correlation test. Levene's test evaluated the homogeneity of variance. To obtain predictive equations analysis was used stepwise multiple linear regression. Results: There was no significant difference in mean age between the PRM. The male adolescents, regardless of age, showed superiority in MRP values when compared to the opposite sex. Weight, height and sex correlated with the PRM. Regression analysis suggested in this study, pointed out that the weight and sex had an influence in MIP and MEP only in relation to sex influenced. The mean for each PRM adolescents classified as very active were superior to those observed in adolescents classified as irregularly active. Conclusion: This study provides reference values and two models of predictive equations for maximal inspiratory and expiratory pressures, and to establish the lower limits of normality that will serve as an indispensable condition for careful evaluation of respiratory muscle strength in Brazilian adolescents

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Lip squamous cell carcinoma (SCC) may develop from a premalignant condition, actinic cheilitis (AC) in 95% of the cases. Both premalignant and neoplastic lip diseases are caused mainly by chronic exposure to the ultraviolet component of solar radiation, especially UVB. This exposure causes disruption of the cell cycle and damage to DNA repair systems, like mismatch repair, altering proteins repair as hMLH1 and hMSH2. This research aimed to investigate the immunohistochemical expression of hMLH1 and hMSH2 proteins in lower lip SCCs and ACs, providing additional information about carcinogenesis of the lower lip. The sample consisted 40 cases of ACs and 40 cases of lower lip SCCs. Histological sections of 3 μm were submitted to immunoperoxidase method, for immunohistochemical analysis of lesions were counted in 1000 cells (positive and negative), data were evaluated both in absolute numbers and percentage of immunostained cells, the latter by assigning scores. Associations of the variables and comparative analysis of biomarker expression were performed by Fisher s exact and Pearson s chi-square, "t" student, one-way ANOVA, Mann- Whitney e Kruskal-Wallis tests. The level of significance was 5%. It was found that, in lower lip SCC, the mean of the proteins was higher in female patients (hMLH1= 369,80 + 223,98; hMHS2 = 534,80 + 343,62), less than 50 years old (hMLH1 = 285,50 + 190,65; hMHS2 = 540,00 + 274,79) and classified as low-grade malignancy (hMLH1 = 264,59 + 179,21; hMHS2 = 519,32 + 302,58), in these data only to sex, for hMLH1 protein, was statistically significant (p=0.034). Comparing the different lesions, we observed that for both hMLH1 and hMSH2 protein, the average of positive epithelial cells decreased as the lesion was graded at later stages. The ACs classified without dysplasia or mild dysplasia had the highest average of immunostained cells (hMLH1 = 721.23 + 88.116; hMHS2 = 781.50 + 156.93). The ACs classified as moderate or severe dysplasia had intermediate values (hMLH1 = 532,86 + 197,72; hMHS2 = 611,14 + 172,48) and SSCs of the lower lip had the lowest averages (hMLH1 = 255,03 + 199,47; hMHS2 = 518,38 + 265,68). There was a statistically significant difference between groups (p<0.001). In conclusion, our data support the hypothesis that changes in immunoexpression of these proteins is related to the process of carcinogenesis of the lower lip

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In systems that combine the outputs of classification methods (combination systems), such as ensembles and multi-agent systems, one of the main constraints is that the base components (classifiers or agents) should be diverse among themselves. In other words, there is clearly no accuracy gain in a system that is composed of a set of identical base components. One way of increasing diversity is through the use of feature selection or data distribution methods in combination systems. In this work, an investigation of the impact of using data distribution methods among the components of combination systems will be performed. In this investigation, different methods of data distribution will be used and an analysis of the combination systems, using several different configurations, will be performed. As a result of this analysis, it is aimed to detect which combination systems are more suitable to use feature distribution among the components

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Classifier ensembles are systems composed of a set of individual classifiers and a combination module, which is responsible for providing the final output of the system. In the design of these systems, diversity is considered as one of the main aspects to be taken into account since there is no gain in combining identical classification methods. The ideal situation is a set of individual classifiers with uncorrelated errors. In other words, the individual classifiers should be diverse among themselves. One way of increasing diversity is to provide different datasets (patterns and/or attributes) for the individual classifiers. The diversity is increased because the individual classifiers will perform the same task (classification of the same input patterns) but they will be built using different subsets of patterns and/or attributes. The majority of the papers using feature selection for ensembles address the homogenous structures of ensemble, i.e., ensembles composed only of the same type of classifiers. In this investigation, two approaches of genetic algorithms (single and multi-objective) will be used to guide the distribution of the features among the classifiers in the context of homogenous and heterogeneous ensembles. The experiments will be divided into two phases that use a filter approach of feature selection guided by genetic algorithm

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The vascular segmentation is important in diagnosing vascular diseases like stroke and is hampered by noise in the image and very thin vessels that can pass unnoticed. One way to accomplish the segmentation is extracting the centerline of the vessel with height ridges, which uses the intensity as features for segmentation. This process can take from seconds to minutes, depending on the current technology employed. In order to accelerate the segmentation method proposed by Aylward [Aylward & Bullitt 2002] we have adapted it to run in parallel using CUDA architecture. The performance of the segmentation method running on GPU is compared to both the same method running on CPU and the original Aylward s method running also in CPU. The improvemente of the new method over the original one is twofold: the starting point for the segmentation process is not a single point in the blood vessel but a volume, thereby making it easier for the user to segment a region of interest, and; the overall gain method was 873 times faster running on GPU and 150 times more fast running on the CPU than the original CPU in Aylward

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The occurrence of problems related to the scattering and tangling phenomenon, such as the difficulty to do system maintenance, increasingly frequent. One way to solve this problem is related to the crosscutting concerns identification. To maximize its benefits, the identification must be performed from early stages of development process, but some works have reported that this has not been done in most of cases, making the system development susceptible to the errors incidence and prone to the refactoring later. This situation affects directly to the quality and cost of the system. PL-AOVgraph is a goal-oriented requirements modeling language which offers support to the relationships representation among requirements and provides separation of crosscutting concerns by crosscutting relationships representation. Therefore, this work presents a semi-automatic method to crosscutting concern identification in requirements specifications written in PL-AOVgraph. An adjacency matrix is used to identify the contributions relationships among the elements. The crosscutting concern identification is based in fan-out analysis of contribution relationships from the informations of adjacency matrix. When identified, the crosscutting relationships are created. And also, this method is implemented as a new module of ReqSys-MDD tool

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Self-adaptive software system is able to change its structure and/or behavior at runtime due to changes in their requirements, environment or components. One way to archieve self-adaptation is the use a sequence of actions (known as adaptation plans) which are typically defined at design time. This is the approach adopted by Cosmos - a Framework to support the configuration and management of resources in distributed environments. In order to deal with the variability inherent of self-adaptive systems, such as, the appearance of new components that allow the establishment of configurations that were not envisioned at development time, this dissertation aims to give Cosmos the capability of generating adaptation plans of runtime. In this way, it was necessary to perform a reengineering of the Cosmos Framework in order to allow its integration with a mechanism for the dynamic generation of adaptation plans. In this context, our work has been focused on conducting a reengineering of Cosmos. Among the changes made to in the Cosmos, we can highlight: changes in the metamodel used to represent components and applications, which has been redefined based on an architectural description language. These changes were propagated to the implementation of a new Cosmos prototype, which was then used for developing a case study application for purpose of proof of concept. Another effort undertaken was to make Cosmos more attractive by integrating it with another platform, in the case of this dissertation, the OSGi platform, which is well-known and accepted by the industry

Relevância:

100.00% 100.00%

Publicador:

Resumo:

One way to deal with the high complexity of current software systems is through selfadaptive systems. Self-adaptive system must be able to monitor themselves and their environment, analyzing the monitored data to determine the need for adaptation, decide how the adaptation will be performed, and finally, make the necessary adjustments. One way to perform the adaptation of a system is generating, at runtime, the process that will perform the adaptation. One advantage of this approach is the possibility to take into account features that can only be evaluated at runtime, such as the emergence of new components that allow new architectural arrangements which were not foreseen at design time. In this work we have as main objective the use of a framework for dynamic generation of processes to generate architectural adaptation plans on OSGi environment. Our main interest is evaluate how this framework for dynamic generation of processes behave in new environments

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The development of computers and algorithms capable of making increasingly accurate and rapid calculations as well as the theoretic foundation provided by quantum mechanics has turned computer simulation into a valuable research tool. The importance of such a tool is due to its success in describing the physical and chemical properties of materials. One way of modifying the electronic properties of a given material is by applying an electric field. These effects are interesting in nanocones because their stability and geometric structure make them promising candidates for electron emission devices. In our study we calculated the first principles based on the density functional theory as implemented in the SIESTA code. We investigated aluminum nitride (AlN), boron nitride (BN) and carbon (C), subjected to external parallel electric field, perpendicular to their main axis. We discuss stability in terms of formation energy, using the chemical potential approach. We also analyze the electronic properties of these nanocones and show that in some cases the perpendicular electric field provokes a greater gap reduction when compared to the parallel field