7 resultados para non-ideal problems

em Universidade Federal do Rio Grande do Norte(UFRN)


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Nowadays, optic fiber is one of the most used communication methods, mainly due to the fact that the data transmission rates of those systems exceed all of the other means of digital communication. Despite the great advantage, there are problems that prevent full utilization of the optical channel: by increasing the transmission speed and the distances involved, the data is subjected to non-linear inter symbolic interference caused by the dispersion phenomena in the fiber. Adaptive equalizers can be used to solve this problem, they compensate non-ideal responses of the channel in order to restore the signal that was transmitted. This work proposes an equalizer based on artificial neural networks and evaluates its performance in optical communication systems. The proposal is validated through a simulated optic channel and the comparison with other adaptive equalization techniques

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La recherche prend comme point de départ la dimension formative du mémoire de formation, considerée comme constitutive de l´écriture de soi, et cherche à problématiser cette dimension au tour du questionnement suivant: Comment le mémoire de formation devient-il un instrument de recherche-action-formation? Les analyses s´appuient sur les principes théoriques du paradigme anthropoformateur, proposé par Pineau (2005), les études réalisées par Passeggi (2006ª, 2006b, 2007, 2008ª, 2008b) sur les mémoires, les travaux de recherche de Nóvoa (1988, 1995), de Josso (2004), de Souza (2006) et de Fontana (2000), qui conçoivent la formação du point de vue de l´ apprenant. L´univers de la recherche s´est circonscrit à la situation de formation des éducateurs de la zone rurale, étudiants en Pédagogie dans le PROFORMAÇÃO (CAMEAM), à l´Univeristé de l´Etat du Rio Grande du Nord (UERN), pendant le second semestre de 2005. La recherche a croisé diférents types de démarche pour recueillir les données empiriques: l´observation du processus d´élaboration des mémoires; un questionnaire; des entretiens informels avec les enseignants en formation et avec les formateurs; et 09 mémoires, écrits par les participants de la recherche. Les analyses des données empiriques montrent que l´écriture des mémoires, en tant que démarche de recherche-action-formation, révelent que la dimension formative se dédouble en d´autres dimensions: etnosociologique, heuristique, herméneutique, social et afective, autopoiétique et politique. Dans la quête de soi (recherche), mise en oeuvre dans et par l´écriture (action), chaque narrateur construit de nouveaux sens à la vie et (re)signifient les représentations de soi (formation). Les résultats confirment la richesse et les potentialités du mémoire, même dans des conditions non ideal, ce qui permet d´affirmer as valeur travail académique important dans la formation des enseignants

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Internet applications such as media streaming, collaborative computing and massive multiplayer are on the rise,. This leads to the need for multicast communication, but unfortunately group communications support based on IP multicast has not been widely adopted due to a combination of technical and non-technical problems. Therefore, a number of different application-layer multicast schemes have been proposed in recent literature to overcome the drawbacks. In addition, these applications often behave as both providers and clients of services, being called peer-topeer applications, and where participants come and go very dynamically. Thus, servercentric architectures for membership management have well-known problems related to scalability and fault-tolerance, and even peer-to-peer traditional solutions need to have some mechanism that takes into account member's volatility. The idea of location awareness distributes the participants in the overlay network according to their proximity in the underlying network allowing a better performance. Given this context, this thesis proposes an application layer multicast protocol, called LAALM, which takes into account the actual network topology in the assembly process of the overlay network. The membership algorithm uses a new metric, IPXY, to provide location awareness through the processing of local information, and it was implemented using a distributed shared and bi-directional tree. The algorithm also has a sub-optimal heuristic to minimize the cost of membership process. The protocol has been evaluated in two ways. First, through an own simulator developed in this work, where we evaluated the quality of distribution tree by metrics such as outdegree and path length. Second, reallife scenarios were built in the ns-3 network simulator where we evaluated the network protocol performance by metrics such as stress, stretch, time to first packet and reconfiguration group time

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In the present work are established initially the fundamental relationships of thermodynamics that govern the equilibrium between phases, the models used for the description of the behavior non ideal of the liquid and vapor phases in conditions of low pressures. This work seeks the determination of vapor-liquid equilibrium (VLE) data for a series of multicomponents mixtures of saturated aliphatic hydrocarbons, prepared synthetically starting from substances with analytical degree and the development of a new dynamic cell with circulation of the vapor phase. The apparatus and experimental procedures developed are described and applied for the determination of VLE data. VLE isobarics data were obtained through a Fischer s ebulliometer of circulation of both phases, for the systems pentane + dodecane, heptane + dodecane and decane + dodecane. Using the two new dynamic cells especially projected, of easy operation and low cost, with circulation of the vapor phase, data for the systems heptane + decane + dodecane, acetone + water, tween 20 + dodecane, phenol + water and distillation curves of a gasoline without addictive were measured. Compositions of the equilibrium phases were found by densimetry, chromatography, and total organic carbon analyzer. Calibration curves of density versus composition were prepared from synthetic mixtures and the behavior excess volumes were evaluated. The VLE data obtained experimentally for the hydrocarbon and aqueous systems were submitted to the test of thermodynamic consistency, as well as the obtained from the literature data for another binary systems, mainly in the bank DDB (Dortmund Data Bank), where the Gibbs-Duhem equation is used obtaining a satisfactory data base. The results of the thermodynamic consistency tests for the binary and ternary systems were evaluated in terms of deviations for applications such as model development. Later, those groups of data (tested and approved) were used in the KijPoly program for the determination of the binary kij parameters of the cubic equations of state original Peng-Robinson and with the expanded alpha function. These obtained parameters can be applied for simulation of the reservoirs petroleum conditions and of the several distillation processes found in the petrochemistry industry, through simulators. The two designed dynamic cells used equipments of national technology for the determination of VLE data were well succeed, demonstrating efficiency and low cost. Multicomponents systems, mixtures of components of different molecular weights and also diluted solutions may be studied in these developed VLE cells

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In the present work are established initially the fundamental relationships of thermodynamics that govern the equilibrium between phases, the models used for the description of the behavior non ideal of the liquid and vapor phases in conditions of low pressures. This work seeks the determination of vapor-liquid equilibrium (VLE) data for a series of multicomponents mixtures of saturated aliphatic hydrocarbons, prepared synthetically starting from substances with analytical degree and the development of a new dynamic cell with circulation of the vapor phase. The apparatus and experimental procedures developed are described and applied for the determination of VLE data. VLE isobarics data were obtained through a Fischer's ebulliometer of circulation of both phases, for the systems pentane + dodecane, heptane + dodecane and decane + dodecane. Using the two new dynamic cells especially projected, of easy operation and low cost, with circulation of the vapor phase, data for the systems heptane + decane + dodecane, acetone + water, tween 20 + dodecane, phenol + water and distillation curves of a gasoline without addictive were measured. Compositions of the equilibrium phases were found by densimetry, chromatography, and total organic carbon analyzer. Calibration curves of density versus composition were prepared from synthetic mixtures and the behavior excess volumes were evaluated. The VLE data obtained experimentally for the hydrocarbon and aqueous systems were submitted to the test of thermodynamic consistency, as well as the obtained from the literature data for another binary systems, mainly in the bank DDB (Dortmund Data Bank), where the Gibbs-Duhem equation is used obtaining a satisfactory data base. The results of the thermodynamic consistency tests for the binary and ternary systems were evaluated in terms of deviations for applications such as model development. Later, those groups of data (tested and approved) were used in the KijPoly program for the determination of the binary kij parameters of the cubic equations of state original Peng-Robinson and with the expanded alpha function. These obtained parameters can be applied for simulation of the reservoirs petroleum conditions and of the several distillation processes found in the petrochemistry industry, through simulators. The two designed dynamic cells used equipments of national technology for the determination Humberto Neves Maia de Oliveira Tese de Doutorado PPGEQ/PRH-ANP 14/UFRN of VLE data were well succeed, demonstrating efficiency and low cost. Multicomponents systems, mixtures of components of different molecular weights and also diluted solutions may be studied in these developed VLE cells

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This study aimed to understand the typical ideal of the nursing technician about the systematization of nursing care in the light of the theoretical framework of Alfred Schutz. It is a comprehensive phenomenological research, using the theoretical framework of Alfred Schutz. For the unveiling of the phenomenon (the typical ideal of the nursing technician about the systematization of nursing care), the search process was configured from the proposed guiding principles for a research methodology based on the work itself of Schutz held by Zeferino (2010) in his PhD. For data collection, we used the focus group technique, counting on the collaboration of thirteen practical nurses working in a university hospital in Rio Grande do Norte, who responded positively to the inclusion criteria: working in the study hospital, performing care direct to patients. Forty-four subjects showed interest in participating, being held a draw for selection of the research sample, consisting of 14 professionals, one of whom did not attend the gathering of data collection. The focus group, entitled "What I think about the systematization of nursing care", took place on February 15th, 2013, totaling 101 minutes. It was performed according to the Experiential Education Humanescent using building posters as projective technique, from the key question: "What is the systematization of nursing care for you?". In order to understand some of the biographical situation of the participants, a questionnaire was administered to study participants. From the agreement of the subjects, the focus group was recorded and photographed with the cooperation of one reporter and two other employees. We used Microsoft Word 2010 to perform the transcript of the meeting and Microsoft Excel 2010 for synthesizing the results via a spreadsheet. The study followed the ethical and legal principles that govern scientific research on humans, recommended in Resolution nº 196/96, it was approved by Opinion Embodied Ethics Committee in Research of UFRN (Federal University of Rio Grande do Norte), nº 98 424, of August 31th, 2012, CAAE No. 05906912.0.0000.5537. The analysis of the nursing staff speeches, along with the contemplation of their posters and their written descriptions, allowed from the guiding principles of Zeferino (2010), in light of the reference of Alfred Schutz, unveiling the typical ideal of nursing technicians about the systematization of nursing care, passing four themes: typing of the concept of systematization of nursing care; benefits, which resulted in the reasons to believe in the positivity of this working tool; experienced problems, revealing the world of everyday life of nursing professionals, and possibilities for improvement. It was concluded that the nursing technicians are unaware of the systematization of nursing care. However, they typify a very positive perception about the same, especially with regard to improvements that may foster care

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This research aimed to evaluate the Family Health Strategy (FHS) in Natal, Rio Grande do Norte, through its managers, professionals and users, having as its support the Theory of Belief and the Cognitive-Behavioral Theory. This is a multimethod research and is divided into three sub-studies. In the first study, nine managers answered to a semi-structured interview, to verify the knowledge and beliefs on SUS; the quantitative data were analyzed with descriptive statistics with the aid of SPSS software and the qualitative data were submitted to lexical analysis with support of ALCESTE software. In the second study, we have a descriptive correlational research in which the antecedent variables are related to working conditions in the family health units (FHUs) and to the professionals‟ profile; the corresponding variables refer to the evaluations of the FHS; a stratified probabilistic sample with 475 professionals, who answered to two scales, both consisting of three factors: Physical infrastructure, Material resources, and Treatment effectiveness, and data were analyzed using descriptive, bivariate and multivariate statistics, with the aid of SPSS. The third study is a descriptive correlational research in which the antecedent variables refer to the treatment in the FHUs and to the users‟ profile, and the corresponding variables refer to the evaluations of the FHS, with a stratified non-probabilistic sample with 390 users, who contributed to the construction of a new scale with a factor, effectiveness in treatment, analyzed through descriptive, bivariate and multivariate statistics, with the aid of SPSS. The results showed problems which start from management, under the shape of admission due to political indication and lack of knowledge on SUS and the FHS; they pass through the low tenure of professionals and insufficient professional; and they end up spreading all over the analyzed items: infrastructure of FHUs, material resources, professionals‟ training, accessibility and referral system. One concludes that, despite following an ideal model, the FHS is in need of changes with regard to the barriers to its operational reality