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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

QPPOA : framework para qualifica??o do processo de produ??o de objetos de aprendizagem / QPPOA : a framework for qualification of the process of learning objects production

Guterres, Jo?o Pedro Dewes 08 March 2017 (has links)
Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-06-29T13:41:09Z No. of bitstreams: 1 DIS_JOAO_PEDRO_DEWES_GUTERRES_COMPLETO.pdf: 2705657 bytes, checksum: 78e3e0209e2f1af3b1e4d3cdc87b84a3 (MD5) / Made available in DSpace on 2017-06-29T13:41:09Z (GMT). No. of bitstreams: 1 DIS_JOAO_PEDRO_DEWES_GUTERRES_COMPLETO.pdf: 2705657 bytes, checksum: 78e3e0209e2f1af3b1e4d3cdc87b84a3 (MD5) Previous issue date: 2017-03-08 / The production of learning objects allied the areas of technology and education, being a key factor to bring new possibilities of learning. Due to the increase in computational resources, the production of this type of educational material grew and began to incorporate practices of software production in general, highlighting some peculiarities due to the educational objectives proposed in the objects. Thereat, the introduction of Software Engineering practices is increasingly present in the production of learning objects, and, as in software production, the qualification of this production process has become a necessity. In software production, a consolidated solution for production qualification is in the evaluation frameworks, such as CMMI and MPS.BR. In order to think this type of solution for the production of learning objects, this research presents a framework to support the reflection on the practices performed by the centers of production of learning objects. This framework is a result of the triangulation of pertinent practices related to the theme obtained from a literature review (including a systematic review and systematic mapping) and from interviews with members of nine Brazilian learning object centers. As a result obtained after the analysis of adherence of the practices by the centers, stands out its capacity to promote the reflection of the production process, as well as well as to encourage them to carry out new practices. / A produ??o de objetos de aprendizagem aliou as ?reas da tecnologia e da educa??o, sendo um fator chave para trazer novas possibilidades de aprendizagem. Devido ao aumento dos recursos computacionais, a produ??o desse tipo de material educacional cresceu e passou a incorporar pr?ticas da produ??o de software em geral, destacando-se algumas peculiaridades por conta dos objetivos educacionais propostos nos objetos. Com isso, a introdu??o de pr?ticas de Engenharia de Software est? cada vez mais presente na produ??o dos objetos de aprendizagem, e, assim como na produ??o de software, a qualifica??o deste processo de produ??o se tornou uma necessidade. Na produ??o de software, uma solu??o consolidada para qualifica??o da produ??o est? nos frameworks de avalia??o, como o CMMI e MPS.BR. De modo a pensar esse tipo de solu??o para a produ??o de objetos de aprendizagem, esta pesquisa apresenta um framework para apoiar a reflex?o sobre as pr?ticas realizadas pelos centros de produ??o de objetos de aprendizagem. Esse framework ? resultado da triangula??o de pr?ticas pertinentes relacionadas ao tema obtidas a partir de uma revis?o de literatura (incluindo uma revis?o e um mapeamento sistem?tico), de observa??es do pesquisador e de entrevistas com integrantes de nove centros brasileiros de produ??o de objetos de aprendizagem. Como resultado obtido ap?s a an?lise de ader?ncia das pr?ticas pelos centros, destaca-se a capacidade de promover a reflex?o do processo de produ??o e das pr?ticas dos centros de produ??o de objetos de aprendizagem, bem como de incentiv?-los ? realiza??o de novas pr?ticas.
2

Controlador preditivo n?o linear aplicado ao controle de golfadas em processos de produ??o de petr?leo / Nonlinear model predictive controller applied to slug control in oil production processes

Dantas Junior, Gaspar Fontineli 23 January 2014 (has links)
Made available in DSpace on 2014-12-17T14:56:17Z (GMT). No. of bitstreams: 1 GasparFDJ_DISSERT.pdf: 3388304 bytes, checksum: 086a8f61099f69978a8b9f477f351d24 (MD5) Previous issue date: 2014-01-23 / Petr?leo Brasileiro SA - PETROBRAS / Slugging is a well-known slugging phenomenon in multiphase flow, which may cause problems such as vibration in pipeline and high liquid level in the separator. It can be classified according to the place of its occurrence. The most severe, known as slugging in the riser, occurs in the vertical pipe which feeds the platform. Also known as severe slugging, it is capable of causing severe pressure fluctuations in the flow of the process, excessive vibration, flooding in separator tanks, limited production, nonscheduled stop of production, among other negative aspects that motivated the production of this work . A feasible solution to deal with this problem would be to design an effective method for the removal or reduction of the system, a controller. According to the literature, a conventional PID controller did not produce good results due to the high degree of nonlinearity of the process, fueling the development of advanced control techniques. Among these, the model predictive controller (MPC), where the control action results from the solution of an optimization problem, it is robust, can incorporate physical and /or security constraints. The objective of this work is to apply a non-conventional non-linear model predictive control technique to severe slugging, where the amount of liquid mass in the riser is controlled by the production valve and, indirectly, the oscillation of flow and pressure is suppressed, while looking for environmental and economic benefits. The proposed strategy is based on the use of the model linear approximations and repeatedly solving of a quadratic optimization problem, providing solutions that improve at each iteration. In the event where the convergence of this algorithm is satisfied, the predicted values of the process variables are the same as to those obtained by the original nonlinear model, ensuring that the constraints are satisfied for them along the prediction horizon. A mathematical model recently published in the literature, capable of representing characteristics of severe slugging in a real oil well, is used both for simulation and for the project of the proposed controller, whose performance is compared to a linear MPC / A golfada ? um regime inst?vel do fluxo multif?sico, com oscila??es de press?o e vaz?o abruptas no processo de produ??o de petr?leo, podendo ocasionar problemas tais como vibra??o na tubula??o e alto n?vel de l?quido nos separadores. Pode ser classificada de acordo com seu local de ocorr?ncia. A mais severa destas, conhecida como golfada no riser, ocorre na tubula??o vertical que alimenta a plataforma. Conhecida tamb?m como golfada severa, ela ? capaz de causar bruscas oscila??es na press?o, nas vaz?es do processo, vibra??o excessiva, inunda??o dos tanques separadores, produ??o limitada, parada n?o programada da plataforma, entre outros aspectos negativos que motivaram a produ??o deste trabalho. Uma solu??o vi?vel para lidar com tal problema seria projetar um m?todo efetivo para a remo??o ou diminui??o deste regime, como um controlador. De acordo com a literatura, o controlador convencional PID n?o apresenta bons resultados devido ao alto grau de n?o linearidade do processo, o que impulsionou o desenvolvimento de t?cnicas avan?adas de controle. Dentre estas, o controlador preditivo, cuja a??o de controle resulta da solu??o de um problema de otimiza??o, al?m de ser uma t?cnica que apresenta robustez e pode incorporar restri??es f?sicas e/ou de seguran?a. O objetivo deste trabalho ? estudar a aplica??o de uma t?cnica de controle preditivo n?o linear ao controle de golfada severa, visando controlar a quantidade de massa l?quida no riser atuando na v?lvula de produ??o e, indiretamente, suprimir as oscila??es de vaz?o e press?o. Com a finalidade de obter benef?cios ambientais e econ?micos. A t?cnica de controle preditivo proposta baseia-se no uso de aproxima??es lineares do modelo e na resolu??o repetida de um problema de otimiza??o quadr?tica que proporciona solu??es que melhoram a cada itera??o. No caso em que a converg?ncia desse algoritmo ? satisfeita, os valores preditos das vari?veis do processo s?o iguais ?queles que seriam obtidos pelo modelo n?o linear original, garantindo que as restri??es nessas vari?veis sejam satisfeitas ao longo do horizonte de predi??o. Um modelo matem?tico publicado recentemente na literatura, capaz de representar caracter?sticas da golfada severa em um po?o real, ? utilizado tanto para a simula??o, quanto para projeto do controlador proposto, cujo desempenho ? comparado ao de um controlador preditivo linear

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