10 resultados para branch and price

em Universidade Federal do Rio Grande do Norte(UFRN)


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This study aims to investigate the influence of the balance of payments constrained on economic growth in Brazil from 1991 to 2010. With this order, are shown some of the Keynesian balance of payments constrained growth models, inspired by Thirlwall (1979) and Kaldor (1970), which are supported by important points in common, such as adherence to the principle of effective demand. Given that within this theoretical perspective, there is no consensus about the best model to explain the growth rate allowed by the balance of payments constraint, the results are presented by the representative of the empirical literature that addresses the topic, which are necessary for understand the Brazilian case. From the estimation of the income elasticity of imports (0.85) via autoregressive vectors with error correction (VEC), it was calculated five growth rates of income, as predicted by the models of Thirlwall (1979), Thirlwall and Hussain (1982), Moreno-Brid (1998, 2003) and Lourenço et al. (2011) and compared with the actual growth rate. The empirical analysis has shown that: it can not reject the presence of external constraint in the Brazilian economy, there is a strong similarity in growth rates provided by different modeling suggest that growth with external constraint. In addition, when using data in quarterly for the period after 1990 there are no factors that could cause instability in the parameters of the import function (income elasticity and price elasticity of imports) within the period, which indicates that the structural break widely associated with the year 1994 was not confirmed by this study

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This paper aims to investigate the factors that influence the satisfaction and fidelity of tennis´s users with the region southern city of Natal, capital of Rio Grande do Norte as the area of analyzing , using the national satisfaction index models as a tool to study. In this study was used the questionnaire as a tool for collecting data based on the new Norwegian customer satisfaction barometer model proposed by Johnson et. al. (2001). The data collection took place during the months of May and June 2008, when 450 tennis´s users were interviewed. The main results obtained by multiple regression analysis and logistic regression showed that the users' satisfaction with the tennis´s brand is influenced by the quality, comfort, material used in the manufacture and price, while fidelity is potentized by the image of the brand and the satisfaction degree with the user's tennis and with the brand of tennis. In relation to user satisfaction with the tennis, that satisfaction is influenced by the quality, comfort, weight and the material used, while fidelity is potentized by the satisfaction with the tennis´s brand, with the possibility of paying the same amount again and the emotional commitment. As the processing of claims there was no direct influence on satisfaction and consumers fidelity due to the low number complaints

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The objective of this thesis was studying the factors which contribute to customer s satisfaction and loyalty, focusing the Norwegian model of satisfaction and loyalty of the consumer, applied in the sector of hotel services in Natal/RN, Brazil. The theoretical research was led through the concepts of service quality, customer satisfaction and loyalty, models of quality management systems, national index of customer s satisfaction and methods which evaluate the customer s satisfaction. The field research was carried through from December 1st of 2004 to 24 st, among 381 international tourists who had been housed in the hotels of Natal. The analyses of the data had been made through the descriptive statistics and analysis of multiple regression. The results had evidenced that the main precedents variables of satisfaction had been: hotel s room, staff friendliness, hotel restaurant food and price paid; these are factors which explained, in 56,0% the variation of satisfaction with hotels. In relation to the constructs which had influenced the tourist s loyalty, were founds: tourist s satisfaction, hotel image and affective commitment, which had explained 53.0% of the data variability. The complaint management resulted as a basic factor for the tourist s satisfaction and loyalty

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This Thesis deals with a study on customer satisfaction and loyalty focusing on a model of factors antecedents of customer satisfaction and loyalty. The model is based on a Satisfaction Index model adopted in Norway developed by Johnson et al.(2001) and the service quality drivers from the literature. It is surveyed a sample of tourist in Natal. It is used a survey questionnaire applied at the airport in the departure moment of the tourist. The final sample results on 198 cases. Is is used a multiple regression analysis as the method to verify the factor affecting satisfaction and loyalty. Two models arise from the analysis. The first model concerning satisfaction results with cleaness and hygiene of the bathroom, leisure facilities, employees promptness, and price as the significant factors affecting satisfaction. The model has a R2 of 0.6430 and the also check in service, cleaness of the apartment and the hotel in general, bedroom setting have colinearity with some factors entering the model. The loyalty model results with satisfaction, affective commitment as the main factors affecting loyalty, with a R2 0.5396, and also image has collinearity with satisfaction. A small part of the sample has complained and this factor was not considered in the models. The results are consistent with the literature in term of quality as the main driver of the satisfaction and that it is not the only one factor to explain loyalty

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The direct relationship with the processing, industrial yield and price of milk, the importance of the centesimal composition of milk and their protein fractions has increased for both the dairy industry and for the producers, so it is important to identify the possible causes on variation of these components. The aim of this study was to evaluate the effect of the seasons, order of calving and lactation phase on milk composition and protein fractions in dairy farms in the Agreste and Leste meso-regions, of Rio Grande do Norte State (RN). Milk samples were taken in seven milk farms directly from the bulk tanks except for one farm where samples were taken from higher milking cows producers and heifers. The experiment was done in seven properties with milk samples taken directly from the bulk tanks and in one property were collected from higher production cows and heifers. Composition analyses were carried out for both experiments and sensorial trial was performed for the second experiment only. The data results were submitted to analysis of variance (ANOVA) and Tukey test performed for 5% significance level. In the first experiment was observed response of the seasons, dry and rainy season; while in the second, the effect of the order of calving and lactation phase had influence on milk composition and protein fractions. There was significant response (p < 0.05) for season effects but due to farms. The rainy season had higher averages in the protein, lactose, total solids and nonfat dry extract. Multiparous cows had higher CCS, NUL and PCAS milk contents; while, first calving heifers showed higher average for the sensory attribute, color of milk. The final third of lactation was responsible for the elevation of the levels of almost all milk components and their protein fractions

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The Quadratic Minimum Spanning Tree Problem (QMST) is a version of the Minimum Spanning Tree Problem in which, besides the traditional linear costs, there is a quadratic structure of costs. This quadratic structure models interaction effects between pairs of edges. Linear and quadratic costs are added up to constitute the total cost of the spanning tree, which must be minimized. When these interactions are restricted to adjacent edges, the problem is named Adjacent Only Quadratic Minimum Spanning Tree (AQMST). AQMST and QMST are NP-hard problems that model several problems of transport and distribution networks design. In general, AQMST arises as a more suitable model for real problems. Although, in literature, linear and quadratic costs are added, in real applications, they may be conflicting. In this case, it may be interesting to consider these costs separately. In this sense, Multiobjective Optimization provides a more realistic model for QMST and AQMST. A review of the state-of-the-art, so far, was not able to find papers regarding these problems under a biobjective point of view. Thus, the objective of this Thesis is the development of exact and heuristic algorithms for the Biobjective Adjacent Only Quadratic Spanning Tree Problem (bi-AQST). In order to do so, as theoretical foundation, other NP-hard problems directly related to bi-AQST are discussed: the QMST and AQMST problems. Bracktracking and branch-and-bound exact algorithms are proposed to the target problem of this investigation. The heuristic algorithms developed are: Pareto Local Search, Tabu Search with ejection chain, Transgenetic Algorithm, NSGA-II and a hybridization of the two last-mentioned proposals called NSTA. The proposed algorithms are compared to each other through performance analysis regarding computational experiments with instances adapted from the QMST literature. With regard to exact algorithms, the analysis considers, in particular, the execution time. In case of the heuristic algorithms, besides execution time, the quality of the generated approximation sets is evaluated. Quality indicators are used to assess such information. Appropriate statistical tools are used to measure the performance of exact and heuristic algorithms. Considering the set of instances adopted as well as the criteria of execution time and quality of the generated approximation set, the experiments showed that the Tabu Search with ejection chain approach obtained the best results and the transgenetic algorithm ranked second. The PLS algorithm obtained good quality solutions, but at a very high computational time compared to the other (meta)heuristics, getting the third place. NSTA and NSGA-II algorithms got the last positions

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The Multiobjective Spanning Tree Problem is NP-hard and models applications in several areas. This research presents an experimental analysis of different strategies used in the literature to develop exact algorithms to solve the problem. Initially, the algorithms are classified according to the approaches used to solve the problem. Features of two or more approaches can be found in some of those algorithms. The approaches investigated here are: the two-stage method, branch-and-bound, k-best and the preference-based approach. The main contribution of this research lies in the fact that no research was presented to date reporting a systematic experimental analysis of exact algorithms for the Multiobjective Spanning Tree Problem. Therefore, this work can be a basis for other research that deal with the same problem. The computational experiments compare the performance of algorithms regarding processing time, efficiency based on the number of objectives and number of solutions found in a controlled time interval. The analysis of the algorithms was performed for known instances of the problem, as well as instances obtained from a generator commonly used in the literature

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The working conditions, occupational health, occupational illness and workers quality of life, usually referring to the artisanal activities and the workers with a poor professional support. Because this reality is still present in locals without good infrastructure of social and economic attention, there is a need for a broad knowledge of problems related to the productive processes that include features of unsanitary and unhealthy. Despite the intense process of industrialization promoted by globalization and the growth of developing nations like Brazil, the activities of artisanal and small-scale mining are still suffering from the marginalization of their production processes and their workers. This dissertation deals with the description of mineral-based activities (MBA), especially the activities related to production processes of extraction and processing of red pottery and minerals in pegmatites in Parelhas city, Seridó, Rio Grande do Norte, which are conducted by small mining companies or artisanal miners. The study of the work process was based on direct observation, photographic documentation, ergonomics, health and occupational safety analysis, interviews and structured questionnaire with workers of the two activities. The results indicate the need for improvement in both workplaces (red pottery and pegmatites), adaptation of workers to safety standards specific to the workplace, more attention and care related to ergonomics and occupational safety, greater importance to economic and social relations among performed activities, workers and firms of mineral branch and better and greater integration of social policies, supported by different sectors of society with the intention of transforming the current social, cultural, labor and education situation

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The Quadratic Minimum Spanning Tree (QMST) problem is a generalization of the Minimum Spanning Tree problem in which, beyond linear costs associated to each edge, quadratic costs associated to each pair of edges must be considered. The quadratic costs are due to interaction costs between the edges. When interactions occur between adjacent edges only, the problem is named Adjacent Only Quadratic Minimum Spanning Tree (AQMST). Both QMST and AQMST are NP-hard and model a number of real world applications involving infrastructure networks design. Linear and quadratic costs are summed in the mono-objective versions of the problems. However, real world applications often deal with conflicting objectives. In those cases, considering linear and quadratic costs separately is more appropriate and multi-objective optimization provides a more realistic modelling. Exact and heuristic algorithms are investigated in this work for the Bi-objective Adjacent Only Quadratic Spanning Tree Problem. The following techniques are proposed: backtracking, branch-and-bound, Pareto Local Search, Greedy Randomized Adaptive Search Procedure, Simulated Annealing, NSGA-II, Transgenetic Algorithm, Particle Swarm Optimization and a hybridization of the Transgenetic Algorithm with the MOEA-D technique. Pareto compliant quality indicators are used to compare the algorithms on a set of benchmark instances proposed in literature.

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The Quadratic Minimum Spanning Tree (QMST) problem is a generalization of the Minimum Spanning Tree problem in which, beyond linear costs associated to each edge, quadratic costs associated to each pair of edges must be considered. The quadratic costs are due to interaction costs between the edges. When interactions occur between adjacent edges only, the problem is named Adjacent Only Quadratic Minimum Spanning Tree (AQMST). Both QMST and AQMST are NP-hard and model a number of real world applications involving infrastructure networks design. Linear and quadratic costs are summed in the mono-objective versions of the problems. However, real world applications often deal with conflicting objectives. In those cases, considering linear and quadratic costs separately is more appropriate and multi-objective optimization provides a more realistic modelling. Exact and heuristic algorithms are investigated in this work for the Bi-objective Adjacent Only Quadratic Spanning Tree Problem. The following techniques are proposed: backtracking, branch-and-bound, Pareto Local Search, Greedy Randomized Adaptive Search Procedure, Simulated Annealing, NSGA-II, Transgenetic Algorithm, Particle Swarm Optimization and a hybridization of the Transgenetic Algorithm with the MOEA-D technique. Pareto compliant quality indicators are used to compare the algorithms on a set of benchmark instances proposed in literature.