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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.
261

Metodologia Fuzzy aplicada ao triângulo de Duval para o diagnóstico de transformadores de potência por meio de análise de gases dissolvidos / Fuzzy methodology applied to the Duval triangle for the diagnosis of power transformers through the analysis of dissolved gases

Veloso, Diogo Pereira 17 February 2017 (has links)
Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2017-04-10T18:58:09Z No. of bitstreams: 2 Dissertação - Diogo Pereira Veloso - 2017.pdf: 3906692 bytes, checksum: 8d731c4df11a717552eb2bbe8b58f5ea (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-04-11T12:52:13Z (GMT) No. of bitstreams: 2 Dissertação - Diogo Pereira Veloso - 2017.pdf: 3906692 bytes, checksum: 8d731c4df11a717552eb2bbe8b58f5ea (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-04-11T12:52:13Z (GMT). No. of bitstreams: 2 Dissertação - Diogo Pereira Veloso - 2017.pdf: 3906692 bytes, checksum: 8d731c4df11a717552eb2bbe8b58f5ea (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-17 / Power transformers are essential equipment in eletric systems. Considered as highly expensive equipment it requires greater attention regarding the occurrence of failures. A failure on equipment can cause serious trouble to the concessionaire responsible for the generation, transmission and distribution of energy. In the present scenario, where legislation has increased the severity with which oversees these failures and demanding a higher efficiency of the same, it is necessary to create appropriate policies to investigas possible equipment failure. These failures can be caused by several factors, among them, the gases dissolved in the oil due to its degeneration. One of the most used techniques for the diagnosis of power transformers from these dissolved gases is the Duval Triangle, a method that has a precision and considerably high reliability. However, for proper planning of maintenance, avoiding a possible sudden withdrawal and supply cut, it is necessary to provide further information, including a quantitative analysis of the causes of failure and a history of the evolution of the operating status of the machine. To this end it is proposed to use a fuzzy logic by the method of Duval to provide an analysis of the transitions between the diagnostic originally presented to enable monitor the level of relevance of each possible cause for the diagnosis equipment allowing perform scheduled and preventive maintenance. The proposed methodology was validated using real data equipment in operation in the brazilian electric system. / Transformadores de potência são equipamentos essenciais em um sistema elétrico. São considerados equipamentos de alto custo que requerem uma maior atenção no que tange a ocorrência de falhas. Uma falha em um equipamento pode causar sérios prejuízos à concessionária responsável pela geração, transmissão e distribuição de energia. No cenário atual, onde a legislação vem sempre aumentado o rigor com que fiscaliza essas falhas e cobrando uma maior eficiência das mesmas, faz-se necessário criar políticas adequadas para investigas possíveis falhas nos equipamentos. Falhas essas que podem ser originadas por diversos fatores, dentre eles, pelos gases dissolvidos no óleo devido a sua degeneração. Um dos métodos mais utilizados para diagnóstico de transformadores de potência é a análise de gases dissolvidos utilizando o Triângulo de Duval, que apresenta uma precisão e confiabilidade consideravelmente altas. No entanto, para um planejamento adequado de manutenção, evitando uma possível retirada brusca do equipamento e corte no fornecimento, é necessário prover mais informações, incluindo uma análise quantitativa das causas das falhas e um histórico da evolução do estado operativo do equipamento. Para tanto propõe-se a utilização de uma lógica fuzzy junto ao método de Duval para fornecer uma análise das transições entre os diagnósticos apresentados originalmente de forma a permitir acompanhar a evolução do nível de pertinência de cada possível causa no diagnóstico do equipamento, possibilitando realizar manutenções programadas e preventivas. A metodologia proposta foi validada utilizando dados reais de equipamentos em operação no sistema slétrico brasileiro.
262

Funções aritméticas / Arithmetic Functions

Camila Lopes Montrezor 28 April 2017 (has links)
Neste estudo, apresentamos conteúdos matemáticos adaptáveis tanto para os anos finais do ensino fundamental quanto para o ensino médio. Iniciamos com um conjunto de ideias preliminares: indução matemática, triângulo de Pascal, Binômio de Newton e relações trigonométricas, para a obtenção de fórmulas de somas finitas, em que os valores das parcelas são computados sobre números inteiros consecutivos, e da técnica de transformação de soma finita em telescópica. Enunciamos Progressões Aritméticas e Geométricas como sequências numéricas e suas propriedades, obtendo a soma de seus n primeiros termos, associando com propriedades do triângulo de Pascal. Por fim, descrevemos Funções Aritméticas, Funções Aritméticas Totalmente Multiplicativas e Fortemente Multiplicativas, como sequências de números naturais, com suas operações e propriedades, direcionando ao objetivo de calcular o número de divisores naturais de n, a soma de todos os divisores naturais de n, e assim por diante. Como consequência, exibimos a fórmula de contagem do número de polinômios mônicos irredutíveis. / In this study, we present mathematical content that is adaptable to both of the final years of elementary school and to high school. We start with a set of preliminary ideas: mathematical induction, Pascal\'s triangle, Newton\'s binomial and trigonometric relations, to obtain finite sum formulas, where the parts are computed on consecutive integers, and the technique for transforming a finite sum in telescopic one. We state the Arithmetic and Geometric Progressions as numerical sequences and study their properties, obtaining the sum of their n first terms, associating with properties of the Pascal\'s triangle. Finally, we describe the Arithmetic, Totally Multiplicative and Strongly Multiplicative Arithmetic Functions, as sequences of natural numbers, with their operations and properties, as a way to calculating the number of natural divisors of n, the sum of all natural divisors of n, and so on. As a consequence, we obtain the counting formula of the number of irreducible mononical polynomials.
263

Scan me – Ökad säkerhet med multifactor authentication : En undersökning om effekten vid ökad säkerhet i digitala identifierare / Scan me - Increased security with multifactor authentication : A study of the effect when the security increases in digital identifiers

Borgman, Isabelle January 2016 (has links)
Följande kandidatuppsats undersöker en applikation utifrån tre faktorer: säkerhet, användbarhet och funktionalitet. Arbetet tar fram en prototyp på en identifieringsapplikation som använder sig av QR-koder för att identifiera personer. Identifieringsprocessen är tänkt att fungera i t.ex. en insläppningskö på en pub. QR-koden finns i gästens mobil och dörrvakten använder den framtagna prototypen på en surfplatta eller smartphone för att scanna av gästens QR-kod. Syftet är att undersöka hur användbarheten och funktionaliteten påverkas i en applikation när det läggs till en faktor för att öka säkerheten. Detta undersöks genom ett användartest där 8 testpersoner får testa den framtagna prototypen och ge kommentarer både utifrån en gästs och en dörrvakts perspektiv. Resultaten visar på att användbarheten dras ner något i samband med att säkerheten ökar. Identifiering med hjälp av QR-läsaren tar ungefär 4 sekunder längre än vad det gör att identifiera med den vanliga metoden, d.v.s jämföra ett ID-kort med ett medlemskort. Funktionaliteten ökar i systemet eftersom att det läggs till funktionalitet för att scanna av en QR-kod och jämföra informationen ur den med en databas. Prototypen som har tagits fram i denna kandidatuppsats har utvecklingsmöjligheter och kan användas i andra sammanhang och i andra miljöer; prototypen skulle exempelvis fungera lika bra i ett affärssammanhang där affären kan ersätta sina fysiska medlemskort med en QR-kod och en avläsare för att ge sina kunder förmåner. / The following bachelor thesis examines an application based on three factors: security, usability and functionality. The work presents a prototype of an identification application that uses QR codes to identify a person. The identification process is supposed to work in eg a line to a pub. The QR-code is in the guest's mobile and the doorman uses the prototype, which this thesis presents, on a tablet or smartphone and scan the guest's QR code. The aim is to investigate how the usability and functionality is affected in an application when it is added a factor that increases the apps security. This is examined through a user test where 8 test subjects will test the developed prototype and provide feedback both from a guest and a doormans perspective. The results show that the usability decreases while the security increases. The identification with the QR reader takes about 4 seconds longer than it does to identify with the usual method, i.e. comparing an ID card with a membership card. The functionality in the system increases because we add the functionality to scan a QR-code and compare it's information with a database. The prototype that has been developed in this bachelor thesis has development potential and can be used in other contexts and in other environments; for example the prototype would work equally well in a business context in which the business can replace their membership card with a QR code and a reader to give their customers benefits.
264

Aristotle on social media? : Investigating non-profit organizations’ usage of persuasive language in their posts on Twitter and Facebook

Nelzén, Amanda January 2018 (has links)
This study investigates how non-profit organizations market their organizations and persuades their audience on two different social media platforms. The aim is to examine four non-profit organizations’ use of persuasive language in their Facebook and Twitter posts.  in their Facebook and Twitter posts on their social media pages. The aim is to understand if, how and what linguistic means was are used in the posts through Aristotle’s triangle of rhetoric. His theory consists of the three appeals: ethos, logos and pathos. These three appeals all holds a number of individual features.  with a perspective from classic rhetoric, namely Aristotle’s triangle of rhetoric. The persuasion was examined using Aristotle’s triangle of rhetoric and its appeals ethos, logos, and pathos. The research was carried out by classifying the posts by the three appeals and their features. These defined what linguistic means were used and how. All three appeals are equally important when persuading an audience  public through a text as they are necessary to raise an understanding and interest to the text’s focus. Aristotle argued that when including all three appeals, the text has reached its full extent potential of persuasion. The appeals have their unique attributes and may also persuade when used individually. The An author’s credibility and trust applies to the appeal ethos, logic and reasoning in a of the text applies to logos, and a text that moves its reader’s emotions applies to pathos. The research resulted that aWhether a text’s length matters for its persuasion through a comparison of  the two social media platformshas also been examined through comparing the two social media platformsw. Non-profit organizations do not strive for any profit which make it a challenge for them how to market persuade their organization audience in order and actually be able to be able to continue their work. Many of the posts researched included the appeal pathos which aim mainly to evoke emotions with the readers.
265

Apple OS X i AD-Miljö : möjligheter och begränsningar

Kristoffersson, Henrik, Månsson, Victor January 2015 (has links)
Apples datorer med operativsystemet OS X blir allt vanligare på arbetsplatserna. För att företagets IT-avdelning ska kunna upprätthålla en stabil och säker miljö strävar man efter att standardisera system och hårdvara. Verkligheten stämmer inte alltid överens med IT-avdelningens strävan och anställda vill i ökande grad använda sig av produkter de valt själva. Arbetet har undersökt möjligheterna och begränsningarna med att integrera Apple OS X i Microsofts Active Directory. För att kunna besvara de frågor som använts som avgränsning inleddes arbetet med att metodiskt studera litteratur och på internet publicerade artiklar. Därefter har laborationer med och utan tredjepartsmjukvarorna ADmitMac och Centrify genomförts med inriktning på arbetets avgränsningar. Parallellt med detta har intervjuer av organisationer med olika bakgrund genomförts. Intervjuer och laborationer gav ett resultat som sedan diskuterades i rapportens avslutande del. I analysen gjordes en jämförelse av resultaten från intervjuer samt laborationer. Från detta kunde bland annat följande slutsats dras; För att integrera en dator med Apple OS X i Active Directory fungerar det inbyggda stödet men med begränsad funktionalitet. Med hjälp av tredjepartsmjukvaror utökas stödet och fler funktioner i Active Directory kan användas.
266

What Peace? Grasping the Empirical Realities of Peace(s) in Post-war Mitrovica

Segall, Sandra January 2018 (has links)
Urban peacebuilding has proved particularly challenging in cities contested on grounds of state legitimacy where group identities are salient. Ever since the end of the Kosovo War in 1999, the city of Mitrovica has remained divided and been further polarized by outbreaks of violence, post-war politics, and strained inter-group relations. This single case study describes and conceptualizes the empirical realities of peace in the post-war city by applying the Peace Triangle as an analytical tool for understanding the quality and characteristics of the peace that prevails beyond the cessation of large-scale violence. The author builds on the conceptual model by arguing that a more multifaceted and peace-grounded analysis of peace is necessary. The research paper concludes by suggesting an altered analytical model that may yield a more nuanced understanding of peace(s) by encompassing aspects grounded in peace-conducive activities.
267

Orange farm as informele nedersettingsterrein : 'n geografiese evaluering

Ferreira, Heléne 16 April 2014 (has links)
M.A. (Geography) / Fast growing urbanisation in South Africa has resulted in a shortage of housing. Therefore, a programme of informal housing projects was undertaken. The planning of these informal settlements was detrimental because it was done under crisis management. Informal housing will develop over time to formal urban residence and must therefore be properly planned. The purpose of this study was to determine the suitability of Orange Farm as an informal housing area. The goal was achieved by concentrating on certain physiographical (geology, soil, relief, vegetation and climate) and human aspects. Certain physiographical and human aspects were superimposed to establish areas suitable for informal settlement development. The process was aided by using a Geographic Information System. The fmding of the study was that no area in Orange Farm was suitable for informal settlement development. Areas of more and less suitability were indicated according to the physiographical aspects. The study stressed the role of the Government in addressing the problems of planning an informal settlement. Proper informal settlement planning is necessary to assure that these settlements can develop into healthy formal settlements with minimal cost and time. This research proposes certain factors to be considered very carefully in the planning of informal settlements, for ego detailed geological surveys, soil surveys, vegetation research, climatological research and assessment of costs to supply the necessary services and infrastructure. The above-mentioned factors must be taken into consideration, and therefore be analysed, for each settlement as well as the demographical, economical and cultural characteristics of the specific population group in the settlement.
268

Complex graph algorithms using relational database

Ahmed, Aly 24 August 2021 (has links)
Data processing for Big Data plays a vital role for decision-makers in organizations and government, enhances the user experience, and provides quality results in prediction analysis. However, many modern data processing solutions make a significant investment in hardware and maintenance costs, such as Hadoop and Spark, often neglecting the well established and widely used relational database management systems (RDBMS's). In this dissertation, we study three fundamental graph problems in RDBMS. The first problem we tackle is computing shortest paths (SP) from a source to a target in large network graphs. We explore SQL based solutions and leverage the intelligent scheduling that a RDBMS performs when executing set-at-a-time expansions of graph vertices, which is in contrast to vertex-at-a-time expansions in classical SP algorithms. Our algorithms perform orders of magnitude faster than baselines and outperform counterparts in native graph databases. Second, we studied the PageRank problem which is vital in Google Search and social network analysis to determine how to sort search results and identify important nodes in a graph. PageRank is an iterative algorithm which imposes challenges when implementing it over large graphs. We study computing PageRank using RDBMS for very large graphs using a consumer-grade machine and compare the results to a dedicated graph database. We show that our RDBMS solution is able to process graphs of more than a billion edges in few minutes, whereas native graph databases fail to handle graphs of much smaller sizes. Last, we present a carefully engineered RDBMS solution to the problem of triangle enumeration for very large graphs. We show that RDBMS's are suitable tools for enumerating billions of triangles in billion-scale networks on a consumer grade machine. Also, we compare our RDBMS solution's performance to a native graph database and show that our RDBMS solution outperforms by orders of magnitude. / Graduate
269

Kaskádový Sierpinského monopól / Cascade Sierpinski monopole

Kadlček, Jiří January 2013 (has links)
This master’s thesis describes the theoretical analysis of the Sierpinski triangle structure. On the basis of this structure, a planar version of the Sierpinski monopole is firstly designed. Then, by using a transfer of the planar motive to the conical surface, conical and cascade Sierpinski monopoles are designed. All simulations are calculated by CST Microwave Studio 2011. In the thesis, four types of cascade Sierpinski monopole are proposed. The investigated parameters are reflection coefficient, input impedance, radiation properties, polarization and bandwidth. The attention is primarily focused on the design and experimental verification of the selected conical shape cascade Sierpinski monopole set on the bands GSM 900, GSM 1800 and Wi-fi 2,4 GHz.
270

A critical Analysis of ESG Investments during the Covid-19 Pandemic

Motschmann, Laura January 2022 (has links)
This study deals with the critical analysis of sustainable investments and, therefore, ESG practices on financial performance during the year 2020, when the Covid-19 pandemic hit the financial market. The analysis examines sustainable investments in terms of their actual sustainability, risk, and earnings potential. For an improved tangibility of the findings, the overall market of the developed countries is represented by the two sample indices MSCI World and its sustainable benchmark MSCI World SRI. The analysis focuses on performance, volatility, and gross returns. Additionally, the knowledge of three financial experts supplements the analysis and connects the findings with their professional experience. The interview questions focused on the transparency and traceability of a sustainable investment product, the movement from shareholder-value to the stakeholder approach, the risk of sustainable investments, and the return analysis. The analysis shows that the Covid-19 pandemic has influenced the behavior of investors through the increasing importance of social and environmental topics. The analysis determines that intransparency and greenwashing of sustainable investments pose a danger to investors and are favored by a lack of legal framework conditions. Furthermore, the results reveal that ESG engagement reduces the agency problem and can be considered a stakeholder issue. An examination of market data shows that sustainable investments have a lower extreme risk and are thus subject to lower fluctuations in value during the year of the pandemic. In addition, sustainable investments show an abovemarket average development of value growth and gross returns. The conclusion is that sustainable investments are still in the development stage and need quickly binding legal regulations. Nevertheless, the lower risk, the above-market average performance, and the increasing demand point to a long-term establishment of sustainable investments in the market.

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