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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.
91

Filtros harmônicos passivos: otimização e arranjos híbridos / Passive harmonic filters: optimization and hybrid structures / Filtros passivos de armónicos: optimización y estructuras hibridas

Álvarez, Juan José Pérez [UNESP] 01 September 2016 (has links)
Submitted by JUAN JOSE PEREZ ALVAREZ null (yuanjpa@gmail.com) on 2016-09-09T18:04:31Z No. of bitstreams: 1 Final.pdf: 4688581 bytes, checksum: ffc24669bda0a26530c5591cfd508d95 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-13T13:20:34Z (GMT) No. of bitstreams: 1 alvarez_jjp_me_ilha.pdf: 4688581 bytes, checksum: ffc24669bda0a26530c5591cfd508d95 (MD5) / Made available in DSpace on 2016-09-13T13:20:34Z (GMT). No. of bitstreams: 1 alvarez_jjp_me_ilha.pdf: 4688581 bytes, checksum: ffc24669bda0a26530c5591cfd508d95 (MD5) Previous issue date: 2016-09-01 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Neste trabalho apresenta-se um algoritmo para o dimensionamento de um sistema híbrido de filtragem passivo que considera os filtros ressonantes e os dispositivos eletromagnéticos para mitigação de correntes harmônicas de sequência zero. O objetivo do algoritmo proposto é acrescentar o estudo dos filtros passivos mediante a utilização de métodos de otimização nos modelos matemáticos dos filtros ressonantes e do filtro eletromagnético considerando a interação destes dispositivos com o sistema de distribuição de energia elétrica (SDEE). Os estudos realizados visam aplicar o algoritmo na avaliação de três casos de estudo com diferentes características com o objetivo de verificar: a efetividade dos modelos propostos no cálculo dos parâmetros construtivos das topologias consideradas; o impacto do desequilíbrio das fases no ponto de acoplamento comum (PAC) no dimensionamento e na operação dos filtros passivos estudados; e, por meio da operação conjunta, a eficiência dos filtros medida individualmente, bem como do sistema híbrido de filtragem passivo resultante. Um critério de dimensionamento para o bloqueador eletromagnético usado no algoritmo proposto é também discutido. / This work presents an algorithm for designing a passive filtering hybrid system considering resonant and zero-sequence electromagnetic filters. The proposed algorithm objective is to enrich the study of passive filters by applying optimization methods to the resonant and zerosequence electromagnetic filter models considering their interaction with the distribution energy system (DER). The obtained results, applying the algorithm on three diverse study cases, indicate: the effectiveness of the proposed models in calculating the parameters of the passive filters studied, the negative impact of phase unbalance in the point of common coupling (PCC) over the designing and operation of the passive filters studied and, through a combined operation, a filter efficiency improvement seen individually and by evaluating the passive filtering hybrid system. A criterion for the zero-sequence electromagnetic blocker used by the proposed algorithm is also discussed. / CNPq: 163977/2014-3
92

Sistemas de cultivo integrados baseados no conceito de emissão zero em micro-escala

Erse, Euler Batista 26 February 2004 (has links)
Made available in DSpace on 2015-05-07T14:49:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A great predatory pressure on the reduced number of fishing option has produced difficulty to the market to cover the demand of fishing products. This fact justifies itself by the domain of the linear products that envolve the unilateral technologies of the exploitation of the resources, this limits the possibility of choice of the product. The final objective reached, ends up being of extreme avallability, that causes an interruption of the estability of the environment and has an influence on the social peripheral nucleus. At this moment, the aquaculture has been a solution for this problem. A growing consolidation of its techniques has been happening, making itself equaly comparable to the agriculture in the sence of food production. A new technique, the Zero Emission approach, that says that what is rejected (output) by one, is food (input) for another one, has resulted in a better management of the comercial fishing. New aggregated values are created around a main material processor, generating a new competitive chance and making the profits better and at the same time creating completely new markets and services This project is targeted to the rural producer. It presents here, a productive model related to aquaculture, with microscale production systems, capable of using raw material with zero waste of it. The cultivations that participated of the system are those that could complete the cattle breeding, usually available to these social nucleus. Its also integrated into the new cultivations that would be done paralelly to the the property: a worm cultivation, a fish cultivation and an organic vegetable garden / Uma grande pressão predatória sobre o reduzido número de opções de pescado tem produzido uma dificuldade ao mercado em cobrir a demanda de produtos pesqueiros. Esse fato se justifica pelo domínio dos processos lineares que envolvem as tecnologias unilaterais de explotação destes recursos, o que limita as possibilidades de escolha do produto. O objetivo final alcançado, acaba sendo o uso extremamente parcial dos recursos disponíveis, o que causa uma quebra na estabilidade dinâmica dos ecossistemas e influencia a obtenção de recursos dos núcleos sociais periféricos. Neste momento, a aqüicultura tem surgido como uma adaptação viável de produção. Uma crescente consolidação de suas técnicas se faz notar, colocando a mesma, cada vez mais, em condições de igualdade com o setor agropecuário no que se refere à produção alimentícia. Uma nova técnica, a abordagem "Emissão Zero", que prescreve que o que é rejeito (output) para um, é alimento (input) para outro, tem resultado num melhoramento da arte do gerenciamento comercial pesqueiro. Novos valores agregados são gerados em torno de um processador principal de materiais, criando uma nova margem competitiva e melhorando o fluxo de caixa com o retorno dos investimentos ao mesmo tempo em que mercados e serviços completamente novos são criados. O presente projeto propõe uma alternativa para a geração de novas receitas para o produtor rural. Apresenta-se aqui, um modelo produtivo integrado à aqüicultura, com sistemas de produção em micro-escala, capaz de utilizar as matérias primas e residuais com desperdício zero. As culturas que participaram do sistema são aquelas que poderiam complementar a criação de gado, normalmente disponível a estes núcleos sociais. A mesma se integrou aos novos cultivos que poderiam gerar novos valores agregados àquelas já presentes na propriedade: um minhocário, um cultivo de peixes e uma horta orgânica
93

Filtros harmônicos passivos : otimização e arranjos híbridos /

Álvarez, Juan José Pérez January 2016 (has links)
Orientador: Júlio Borges Souza / Resumo: Neste trabalho apresenta-se um algoritmo para o dimensionamento de um sistema híbrido de filtragem passivo que considera os filtros ressonantes e os dispositivos eletromagnéticos para mitigação de correntes harmônicas de sequência zero. O objetivo do algoritmo proposto é acrescentar o estudo dos filtros passivos mediante a utilização de métodos de otimização nos modelos matemáticos dos filtros ressonantes e do filtro eletromagnético considerando a interação destes dispositivos com o sistema de distribuição de energia elétrica (SDEE). Os estudos realizados visam aplicar o algoritmo na avaliação de três casos de estudo com diferentes características com o objetivo de verificar: a efetividade dos modelos propostos no cálculo dos parâmetros construtivos das topologias consideradas; o impacto do desequilíbrio das fases no ponto de acoplamento comum (PAC) no dimensionamento e na operação dos filtros passivos estudados; e, por meio da operação conjunta, a eficiência dos filtros medida individualmente, bem como do sistema híbrido de filtragem passivo resultante. Um critério de dimensionamento para o bloqueador eletromagnético usado no algoritmo proposto é também discutido. / Abstract: This work presents an algorithm for designing a passive filtering hybrid system considering resonant and zero-sequence electromagnetic filters. The proposed algorithm objective is to enrich the study of passive filters by applying optimization methods to the resonant and zerosequence electromagnetic filter models considering their interaction with the distribution energy system (DER). The obtained results, applying the algorithm on three diverse study cases, indicate: the effectiveness of the proposed models in calculating the parameters of the passive filters studied, the negative impact of phase unbalance in the point of common coupling (PCC) over the designing and operation of the passive filters studied and, through a combined operation, a filter efficiency improvement seen individually and by evaluating the passive filtering hybrid system. A criterion for the zero-sequence electromagnetic blocker used by the proposed algorithm is also discussed. / Mestre
94

Stochastic Differential Games In A Bounded Domain

Suresh Kumar, K 09 1900 (has links) (PDF)
No description available.
95

Briquetagem de Resíduos de Café Cultivado no Sistema Safra Zero / Zero Harvest Grown Coffee Crop Waste Briquetting

Zerbinatti, Oberdan Everton 03 September 2012 (has links)
Made available in DSpace on 2016-05-02T13:54:23Z (GMT). No. of bitstreams: 1 Oberdan Everton Zerbinatti-Dissertacao.pdf: 1435178 bytes, checksum: 8b4c978e8193371e9d98209fed1e759a (MD5) Previous issue date: 2012-09-03 / Plant biomass is all material resulting from photosynthesis, whether or not processed by living beings, features disadvantages as for its irregular shape, low density and high humidity. As a solution to such problem a process consisting of biomass energy densification in a high calorific power solid fuel called referred to as "briquetting" is proposed. In this context coffee, which is one of Brazil's largest commodities and produces biomass in different amounts depending on cultural practices such as pruning, including what we refer to as Zero Harvest System of crop conduction in which such system is based on two types of pruning, one of which consisting of coffee crop collar done at a height ranging from 1.5 to 1.8 meters and primary branch skeletons on the four sides of the plants set 20 cm from the trunk. The main feature of the skeleton is the possibility of its renewing itself as well as increasing the number of productive branches per plant, thus increasing the next harvest. This present work aimed to investigate the feasibility of briquette production. Different percentages of crop residues obtained from Zero Harvest such as branches, leaves and straw were used. All the fresh material was grinded to 5-10mm particles and laid to natural under-shade drying in sheds until they reached 12% moisture content. From their undergoing the briquetting process near natural-wood calorific value briquettes which can even replace wood as fuel were obtained. / A biomassa vegetal é todo o material advindo de fotossíntese, processado ou não por seres vivos, detém desvantagens no que concerne a sua forma irregular, baixa densidade e alta umidade. Para solucionar esta questão propõe-se o processo de briquetagem que consiste na densificação energética da biomassa em um combustível sólido de alto poder calorífico denominado briquete. Neste contexto, a cafeicultura que é uma das maiores commodities brasileira e produzem biomassa em quantidades diferentes dependendo dos tratos culturais como tipos de podas incluindo o que chamamos de Sistema Safra Zero de condução da lavoura, onde este sistema se baseia em dois tipos de podas, ou seja, é feito o decote do cafeeiro a uma altura variando de 1,50 a 1,80 metros e o esqueletamento dos ramos plagiotrópicos nos quatro lados da planta a uma distância de 20 cm do tronco. A principal característica do esqueletamento é a possibilidade de renovar e aumentar o número de ramos produtivos por planta, potencializando a safra posterior. O presente trabalho teve por objetivo investigar a viabilidade de produção de briquetes onde foram utilizadas diferentes porcentagens de restos culturais obtidos no sistema safra zero como, galhos, folhas e palha, todo o material fresco colhido foi moído deixando partículas variando entre 5 a 10 mm, posteriormente colocado para secagem natural à sombra em galpões até que atingiram o teor de umidade 12%. Sendo passado pelo processo de briquetagem obtiveram-se briquetes de poder calorífico próximo ao da lenha natural. Podendo substituir a madeira como combustível.
96

PING-PONG AUTO-ZERO AMPLIFIER WITH RAIL-TO-RAIL OUTPUT BUFFER

Naini, Srikar Reddy 12 October 2018 (has links)
No description available.
97

IT-världens Paradise Hotel – lita inte på någon! : En kvalitativ studie om Zero Trust inom svenska företag och myndigheter

Michel, Johan, Nordgren, Amanda, Boqvist, David January 2023 (has links)
In today's world, network security is of utmost importance for companies and authorities as data and information are increasingly being stored and transmitted through cloud solutions. This has led to a higher risk of cyberattacks. To enhance security during this transition, Zero Trust has emerged as a promising concept, with its direction from an internal IT-environment to a more secure cloud solution. Its main motto "never trust, always verify" emphasizes the importance of a high level of security. This study aims to highlight the significance of Zero Trust and compare the attitudes of Swedish companies and authorities towards its implementation. The study was conducted using semi-structured interviews with IT experts who possess knowledge in this domain. Additionally, a literature review was conducted to connect the outcomes of the interviews with the existing research in the field of Zero Trust. The results indicate that several barriers must be considered during the implementation phase. These include cost-related issues, lack of expertise, and outdated systems that cannot handle Zero Trust at the required security level. Despite these challenges, the respondents' attitudes towards Zero Trust were positive. They believed that it could be applied to sporadic and isolated parts of the network infrastructure, and that striving towards it at a theoretical level was essential.
98

Dopad COVID-19 na bezpečnostní politiku států v oblasti kybernetické bezpečnosti / Impact of COVID-19 on Security Policies of States in the Area of Cyber Security

Rieger, Anastasiya January 2022 (has links)
CHARLES UNIVERSITY FACULTY OF SOCIAL SCIENCES Master of International Security Systems Anastasiya Neskoromna/Rieger Impact of COVID 19 on Security Policies of States in the Area of Cyber Security Abstract Prague 2022 Author: Ms. Anastasiya Neskoromna/Rieger Supervisor: prof. David Erkomashvile, Ph.D. Academic Year: 2021/2022 Abstract The SARS-Cov-19 or in different wording the global Covid pandemic outburst have created an unprecedented scenario for various organizations, agencies and structures. The COVID-19 pandemic in 2020 has become an extraordinary and shocking event for the world community and the global economy. On the part of the authorities, the COVID-19 pandemic is accompanied by sometimes harsh and ambiguous decisions, the consequences of which are felt by people in many countries of the world: movement between countries was stopped, businesses and enterprises were closed, the restriction was created, those who were sick or at risk of infection were isolated. There was also no possible assumption regarding how long such a mode of life will last. Many factors as a consequential chain of reactions from the pandemic in the aggregate have created a pleasant environment for altering and modifying the cybercrime landscape. This work aims to analyze the factorial presence of modification in the sphere...
99

Multilingual Neural Machine Translation for Low Resource Languages

Lakew, Surafel Melaku 20 April 2020 (has links)
Machine Translation (MT) is the task of mapping a source language to a target language. The recent introduction of neural MT (NMT) has shown promising results for high-resource language, however, poorly performing for low-resource language (LRL) settings. Furthermore, the vast majority of the 7, 000+ languages around the world do not have parallel data, creating a zero-resource language (ZRL) scenario. In this thesis, we present our approach to improving NMT for LRL and ZRL, leveraging a multilingual NMT modeling (M-NMT), an approach that allows building a single NMT to translate across multiple source and target languages. This thesis begins by i) analyzing the effectiveness of M-NMT for LRL and ZRL translation tasks, spanning two NMT modeling architectures (Recurrent and Transformer), ii) presents a self-learning approach for improving the zero-shot translation directions of ZRLs, iii) proposes a dynamic transfer-learning approach from a pre-trained (parent) model to a LRL (child) model by tailoring to the vocabulary entries of the latter, iv) extends M-NMT to translate from a source language to specific language varieties (e.g. dialects), and finally, v) proposes an approach that can control the verbosity of an NMT model output. Our experimental findings show the effectiveness of the proposed approaches in improving NMT of LRLs and ZRLs.
100

Elements of Control for a Quadruped Robot

Graber-Tilton, Alexander 30 May 2016 (has links)
No description available.

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