994 resultados para taxa de transporte de elétrons (ETR)
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Telecommunication is one of the most dynamic and strategic areas in the world. Many technological innovations has modified the way information is exchanged. Information and knowledge are now shared in networks. Broadband Internet is the new way of sharing contents and information. This dissertation deals with performance indicators related to maintenance services of telecommunications networks and uses models of multivariate regression to estimate churn, which is the loss of customers to other companies. In a competitive environment, telecommunications companies have devised strategies to minimize the loss of customers. Loosing customers presents a higher cost than obtaining new ones. Corporations have plenty of data stored in a diversity of databases. Usually the data are not explored properly. This work uses the Knowledge Discovery in Databases (KDD) to establish rules and new models to explain how churn, as a dependent variable, are related to a diversity of service indicators, such as time to deploy the service (in hours), time to repair (in hours), and so on. Extraction of meaningful knowledge is, in many cases, a challenge. Models were tested and statistically analyzed. The work also shows results that allows the analysis and identification of which quality services indicators influence the churn. Actions are also proposed to solve, at least in part, this problem
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This work has goal of analyzing the practices of Human Resources in the per missionary enterprises of urban transportation, by bus, in the metropolitan region of de Natal, based on the standard person of the National Program of Quality 2004 and points if they are able to take part as prize-winning in this standard. Also this work aims, through a theoretical evolution of people management and its current practices, the history of the National prize Quality and its main standards, the importance of the urban transportation, its characteristics and the system itself in the metropolitan region of Natal. The research was carried out in 11 enterprises that operated in the area, with several dimensions and forms of management. The research variations were based on the standard person of the 2004 NPQ that deals with the system of work, preparation and development and life quality. In the statistical treatment, discriminated and exploiting analyses were applied. The main obtained results through the research, we can verify an administrative centralization in managers and owners hands; that 45% of the enterprises don t have a Human Resources Department, however, on the other hand, they practice some human Resources politics, indicated by the variations; as to the items system of work, 55% of the enterprises are able; preparing and development, 43%
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The objective of this research is the verification of the competition in the intecity market, after the entrance of new competitors (vans and microbus) regulated and clandestine. For verification of this new view was effected one research of documentary character for the knowledge of the regulation and exploratory character of the system Natal - territory of the Seridó, for thus in making will know this problematic, well as its characteristics, attractivenesses and development of the territory of the Seridó, and its link with the Capital (Natal). Later, through a descriptive exploratory research of the type survey with the passengers to know as these are being taken care and its satisfaction in relation to the regulated companies. With the drivers if focus effected one group, and with the staff of the of sale ticket a research survey, aiming at to know the strategies used for the only company of bus that takes care of the territory of the Seridó, the implantation of these and the consequence of the user. In accordance with the generic tipologia of Porter and its strategies, were perceived that the bus company adopted the strategy of price leadership being competitive, using to advantage its bigger space in the market, already vans and the microbuses with its limited participation bet in a strategy of "differentiation" in its service, effecting faster trips and in the strategy of "approach" we find the not regulated services earn the service to the taste of the user
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This work searches to offer a model to improve spare parts stock management for companies of urban passenger transport by bus, with the consequent progress in their maintenance management. Also known as MRO items (Maintenance, Repair and Operations), these spare parts, according their consumption and demand features, cost, criticity to operation, lead-time, quantity of suppliers, among other parameters, shouldn´t have managed their inventory like normal production items (work in process e final products), that because their features, are managed by more predictable models based, for example, in economic order quantity. In the case specifically of companies of urban passenger transport by bus, items MRO have significant importance in their assets and a bad management of these inventories can cause serious losses to company, leading it even bankrupticy business, in more severe situations which missing spare part provokes vehicles shutdown indefinitely. Given slight attention to the issue, which translates in little literature available about it when compared to that literature about normal items stocks, and due the fact that MRO items be critical to bus urban transport of passengers companies´, it is necessary, so, deepen in this theme searching to give technical and scientific subsidies to companies that work, in many times, empirically, with these so decisive inputs to their business. As a typical portfolio problem, in which there are n items, separated into critical and noncritical, while competing for the same resource, it was developed a new algorithm to aid in a better inventory management of spare parts used only in corrective maintenance (whose failures are unpredictable and random), by analyzing the cost-benefit ratio, which compares the level of service versus cost of each item. The model was tested in a company of urban passenger transport by bus from the city of Natal, who anonymously provided their real data to application in this work
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Increased competition in the market of urban transport, characteristic of the Brazilian cities from years 90, has required actions of the managing agencies to ensure the universality of service, enhancing efficiency and consumer welfare. It grows in the Brazilian municipalities, the need to adopt a systematic performance evaluation in terms of management system of indicators and targets appropriate to the regulatory context, which has the purpose of evaluating the accomplishment and compliance by dealers, of the services granted during the contract period, marked by increasingly long periods. The introduction of an index operational performance in permission contracts/concession in urban buses is intended to establish a regulatory performance, giving the contract a pro-competitive feature and to allow the managing agency the systematic and continuous monitoring of the performance of the delegated service to avoid major deviations from desired performance. A performance assessment model of public transportation companies by bus, and applicable to the case of Natal is proposed. Sought to add the particularities found in the transport system in order to assess the performance of enterprises, contribute to improving the service quality to the population and enable decision-makers a detailed knowledge of the behavior of the licensees
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This work aims to "build" rostering urban bus crews to minimize the cost of overtime. For this purpose a mathematical model was developed based on case study in an urban transport company in the metropolitan region of Natal. This problem is usually known in the literature as the Crew Scheduling Problem (CSP) and classified as NP-hard. The mathematical programming takes into account constraints such as: completion of all trips, daily and maximum allowable range of home and / or food. We used the Xpress-MP software to implement and validate the proposed model. For the tested instances the application of the model allowed a reduction in overtime from 38% to 84%
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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O objetivo neste trabalho foi estudar o efeito do tratamento alcalino da cana-de-açúcar com hidróxido de sódio (1,5 a 50% de NaOH) sobre a digestibilidade total e o consumo de matéria seca das dietas experimentais e as taxas de passagem das canas-de-açúcar. Foram utilizados quatro bovinos mestiços (Zebu x Holandês) alimentados com canas-de-açúcar in natura, hidrolisada, hidrolisada fenada e hidrolisada ensilada como fontes volumosas, constituindo 70% das dietas. O tratamento alcalino foi mais eficiente na fração fibra, proporcionando aumentos de pelo menos 45% na digestibilidade. Os aumentos de 25,0 e 16,7% no consumo das dietas contendo as cana-de-açúcar hidrolisada (1,5% PV) e hidrolisada fenada (1,4% PV) provavelmente foram influenciados pela maior digestibilidade da fibra. Os valores estimados de taxa de passagem ruminal no ceco-cólon e o tempo de retenção em cada compartimento não diferiram entre as cana-de-açúcar in natura, hidrolisada e hidrolisada fenada. Entretanto, para a cana-de-açúcar hidrolisada ensilada, observaram-se as menores taxas (1,5 e 7,4%/h) e o maior tempo de retenção (71,4 horas). Concluiu-se que o tratamento alcalino com hidróxido de sódio, com ou sem fenação, melhorou a digestão da fibra da cana-de-açúcar no trato digestivo total e proporcionou acréscimo do consumo de matéria seca da cana-de-açúcar hidrolisada, sem afetar a taxa de passagem. Entretanto, a posterior ensilagem pode não trazer esses benefícios.
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The use of Natural Gas Vehicle has had a fast increase lately. However, in order to have a continuous success this Program needs to develop converting devices of Otto-cycle engines, gasoline or alcohol, to the use of NGV (Natural Gas Vehicle) that presents low cost, maintaining the same original development of the vehicle and low level of emissions, considering the PROCONVE rules. Due to the need to diversify the matrix in order to avoid energetic dependence and due to strict pollution control, it has increased in the Brazilian market the number of vehicles converted to the use of NGV. The recent regulation of the PROCONVE, determining that the converted engines with kits should be submitted to emission testing, comes to reinforce the necessity of the proposed development. Therefore, if we can obtain kits with the characteristics already described, we can reach a major trust in the market and obtain an increase acceptance of the vehicle conversion for NGV. The use of natural gas as vehicle fuel presents several advantages in relation to liquid fuels. It is a vehicle fuel with fewer indexes of emissions when compared to diesel; their combustion gases are less harmful, with a major level of safety than liquid fuels and the market price is quite competitive. The preoccupation that emerges, and the motivation of this project, is to know which are the main justifications for such technology, well accepted in other countries, with a low index or emission, with a high level of safety, where its maintenance becomes low, reminding that for this it is necessary that this technology has to be used properly, and once available in the market will not motivate interest in the urban transportation companies in Brazil, in research centers in general. Therefore this project exists to show the society in a general way the current vision of the main governmental factors, of the national research centers and of the private companies concerning the use of natural gas vehicles in urban transport vehicles, in order to give a major reliability to the population as well as to motivate national market competitiveness with a low cost and reliable product and to enrich the national technology
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Avaliou-se o efeito da adição de enzimas fibrolíticas (celulase e xilanase) sobre as taxas de passagem de partículas e de diluição e os parâmetros ruminais (pH e nitrogênio amoniacal) em animais consumindo dietas contendo silagem de milho e feno de tifton 85 (Cynodon spp.) como volumoso. Oito bovinos com fístulas no rúmen e no duodeno foram distribuídos em dois quadrados latinos 4 x 4, com os tratamentos distribuídos em esquema fatorial 2 x 2 (duas fontes de volumoso e adição ou não de enzimas). O complexo enzimático foi proveniente de fonte comercial e extraído dos fungos Aspergillus niger e Trichoderma longibrachiatum, sendo fornecido na proporção de 12 g/animal/dia, misturado à ração total. Para as taxas de passagem, foram utilizados como marcadores das fases sólida e líquida o cromo-mordente e o cobalto-EDTA, respectivamente. Não houve efeito das enzimas sobre o pH e as concentrações de N-NH3, que apresentaram médias de 6,5 e 22,10 mg/100 mL, respectivamente. A taxa de passagem de partículas no rúmen não foi influenciada pela suplementação enzimática, com médias de 3,4 e 3,0%/h para as dietas contendo silagem de milho e feno de tifton, respectivamente. A taxa de diluição aumentou de 10,07 para 11,84%/h com a adição de enzimas. A suplementação com enzimas fibrolíticas em dietas formuladas com silagem de milho e feno de tifton como volumoso praticamente não alterou os parâmetros avaliados.
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This thesis carries through an application of Analysis of Multicriterion Decision with use of the method of Analytical Hierarchy Process (AHP) in the problematic one of taking of decision of the adoption of electronic collecting in the system of urban transport in the country, a subject that has been controversial. A modeling of criteria and alternatives is carried through and applied a questionnaire based on method AHP the excellent actors in the system of urban transport - Leading of the Managing Agency Public Municipal theatre of Urban Transports, Controller of Company of Bus, Controller of Labor union, Controller of Union of Companies, Communitarian Leader. The considered alternatives were: the maintenance of the current state with collectors, the implementation of electronic collection without collectors, and the implementation of electronic collection with collectors. The used criteria were: job, impact in the fare, control of the system, easiness of use, information. The study was carried through in the city of Natal, RN, where if the adoption of electronic collection argues and where this implementation in some bus lines between Natal and Parnamirim exists, city that integrates the region of the great Natal. The main results of the method evidence in a dimension, the viability of use of method AHP with questionnaire by means of validation of the judgments with analysis of variance beyond proper the normal mechanisms of analysis of consistency to the method, and in another one, the contribution of the analysis boarding multicriterion to become the judgments more clearly. The main results of the analysis help to show that although to models of criteria and distinct judgments of the actors, the method evidenced that it has inclination the adoption of the electronic collection on the current situation, even so with divergences between the maintenance or not of the collector. The research points to the possibility of accomplishment of the application of the AHP in successive rounds of judgments
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O segundo satélite da Missão Espacial Completa Brasileira (SCD2/MECB) foi colocado em órbita em 23 de Outubro de 1998 e carrega a bordo um experimento de células solares. Célula solar de silício é um dispositivo semicondutor, que pode medir a intensidade da radiação visível e parte da radiação infravermelha (400-1100 nm). O experimento permite medir simultaneamente a insolação direta e parte da radiação solar que é refletida pela Terra para o espaço. Os dados do experimento célula solar são transmitidos em tempo real pela telemetria do satélite e recebidos pela estação terrestre em Cuiabá, MT-Brasil (16°S; 56°W). Este fato limita a cobertura espacial para um círculo sobre a América do Sul. O albedo planetário é obtido dentro desta cobertura e seus valores podem ser agrupados em períodos temporais (anual, sazonal ou mensal), ou podem ser estudados para várias localizações (latitude e longitude) durante a vida do satélite. O coeficiente de transmissão atmosférica ou índice de claridade (Kt), medido em estações meteorológicas na superfície da Terra, junto com o valor medido simultaneamente do albedo planetário, permite calcular o coeficiente de absorção atmosférica (Ka). O método desenvolvido neste trabalho para avaliar Ka considera que o albedo planetário é composto por duas partes: uma refletividade local e uma refletividade não local. Considerando este novo conceito, é definida uma taxa de absorção atmosférica (denominada Ra) que é a razão entre Ka e a potência de irradiância solar líquida, que não atravessou a atmosfera (100%-Kt). A taxa de absorção atmosférica assim definida é independente da cobertura de nuvens. O histograma de freqüência de Ra mostra os valores de 0,86±0,07 e 0,88±0,09 sobre as cidades de Botucatu-SP e do Rio de Janeiro-RJ, durante os anos de 1999 até 2006, respectivamente.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The objective of the dissertation was the realization of kinematic modeling of a robotic wheelchair using virtual chains, allowing the wheelchair modeling as a set of robotic manipulator arms forming a cooperative parallel kinematic chain. This document presents the development of a robotic wheelchair to transport people with special needs who overcomes obstacles like a street curb and barriers to accessibility in streets and avenues, including the study of assistive technology, parallel architecture, kinematics modeling, construction and assembly of the prototype robot with the completion of a checklist of problems and barriers to accessibility in several pathways, based on rules, ordinances and existing laws. As a result, simulations were performed on the chair in various states of operation to accomplish the task of going up and down stair with different measures, making the proportional control based on kinematics. To verify the simulated results we developed a prototype robotic wheelchair. This project was developed to provide a better quality of life for people with disabilities
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The aim of this study was investigate the consolidation of the biodiesel fuel used in (a) engines of urban and intercity bus companies, (b) a stationary engine. It was necessary to investigate and analyze, technologically, if the biodiesel fuels were presenting troubleshooting relative to wear of parts lied to fuel and to evaluate the consumption fluctuations of this fuel. The urban and intercity bus companies, localized in Natal, Rio Grande do Norte state, Brazil, had 41 and 12 vehicles, respectively. It were analyzed datasheet of each one vehicle during three years, since 2008 until 2010 and were interviewed the management of the maintenance team of bus companies relative to aspects concerning the substitution of the diesel fuel by the B5 biodiesel. The second aim of this study was visually inspect the wear of the parts directly lied to combustion process. For this reason, it was investigated a stationary engine, manufactured by Branco BD5, 5 HP of power, fueled by (a) diesel, (b) biodiesel B5, (c) biodiesel B20 and (d) diesel or biodiesel, both contaminated by distilled water. In this engine, its power utilizing biodiesel B5 versus diesel was lower about 5.2% and, in the investigated case of B20 versus diesel, it was lower around 11.5%