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Made available in DSpace on 2014-06-11T19:22:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-20Bitstream added on 2014-06-13T20:49:12Z : No. of bitstreams: 1 romero_mev_me_ilha.pdf: 1382824 bytes, checksum: b46118201c032210f988939bf442defe (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A restauração do sistema de energia elétrica consiste na busca da melhor topologia com o maior número de cargas restauradas e o menor número possível de chaveamentos. Os limites de operação devem ser respeitados, ou seja, a rede deve manter a estrutura radial, os limites de tensão e das capacidades de cargas dos alimentadores e de subestações não devem ser violados. Desta forma, um dos objetivos do procedimento da restauração do serviço em sistemas de energia elétrica é reenergizar a maioria de cargas fora de serviço no menor tempo possível, pela transferência dessas áreas para outros sistemas energizados, sem violar restrições de operações e de projeto. Isso é uma busca constante das empresas concessionárias em atender a satisfação dos clientes e da adequação aos índices de continuidade de serviços impostos pelas agências reguladoras, no caso brasileiro a ANEEL (Agência Nacional de Energia Elétrica). Neste trabalho propõe-se uma técnica para melhorar a confiabilidade de sistemas de distribuição, através da alocação de chaves automáticas para restauração desses sistemas. O problema de alocação de chaves é modelado como um problema de programação não linear restrito, com uma função multiobjetivo. A técnica de solução proposta para resolver tanto o problema de alocação de chaves como o de restauração de sistemas radiais de distribuição é um algoritmo de busca tabu reativa (BTR). Para introduzir a metodologia proposta para solução dos problemas de alocação de chaves e restauração de sistemas de distribuição, são apresentados os aspectos teóricos destes problemas, o sistema de codificação que representa soluções potenciais para o problema, e permite que o mesmo seja resolvido através de meta-heurísticas e o desenvolvimento do trabalho de pesquisa para o planejamento da operação e controle on line de um sistema real / The restoration of electric power system is the search for the best topology with the largest number of loads and restored fewest switching. The operating limits must be respected, in other words, the network must maintain the radial structure, voltage limits and capacity loads of feeders and substations should not be violated. Thus one aim of the procedure of restoration of service in electric power systems is re-energized the most charges out of service in the shortest time possible, and the transfer of these areas to other systems energized, without violating restrictions on operations and constructions. This is a constant search for businesses to meet customer satisfaction and the suitability indices of continuity of services imposed by regulatory agencies, in Brazil, ANEEL (National Agency of Electrical Energy). This paper proposes a technique to improve the reliability of distribution systems, through the allocation of keys for automatic restoration of such systems. The problem of allocation of keys is modeled as a problem of constrained nonlinear programming with a multi-objective function. The technical solution proposed to solve both the problem of assigning keys to the restoration of radial distribution systems is an algorithm of reactive tabu search (RTS). To introduce the proposed methodology for solving problems of allocation of keys and restoration of distribution systems, be present the theoretical aspects of these problems, the coding system that represents potential solutions to the problem, and allows it to be resolved by metaheuristics and development of research work for the planning of the operation and control an online real system

Participants from recent secure email user studies have expressed a need to use secure email tools only a few times a year. At the same time, Internet users are expressing concerns over the permanence of personal information on the Internet. Support for short-lived keys has the potential to address both of these problems. However, the short-lived keys usability and security space is underdeveloped and unexplored. In this thesis, we present an exploration of the short-lived keys usability and security design space. We implement both a short-lived keys and a long-term keys secure email prototype. With these two prototypes, we conduct a within-subjects user study. Results from our study show that participants believe the short-lived keys prototype is more secure and more trusted. Participants also provide feedback on what they want in a system supporting short-lived keys. They also discuss how concerned they are about the permanence of their information on the Internet and on their devices.

Bitcoin har framträtt som den mest igenkännbara kryptovalutan sedan igångsättningen 2009 och har vid skrivande tillfälle ett börsvärde på 1,6 biljoner svenska kronor. Detta ihop med den ekonomiska friheten som Bitcoin erbjuder gör att användarantalet ständigt ökar. Likt all ny teknik så tar det tid innan teknologin är fullt utvecklad och anpassad för den bredda massan. I följd av detta kan säkerheten lida vilket kan resultera till ekonomiska förluster. Denna forskningsinsats undersöker vad för åtgärder och strategier som kan användas för att öka säkerheten via en litteraturstudie. Insatsen undersöker även med hjälp av en enkätundersökning ställd till ett Bitcoin-forum om hur användare av Bitcoin hanterar sina privata nycklar. Arbetet visar att det finns åtgärder som bidrar till ökad säkerhet såsom kryptering och multisignatur men att det hänger mycket på vad användarna själva väljer för typ av bäst strategi för deras användningsområde. Enkätundersökning redovisar att majoriteten av användarna gör säkerhetsmedvetna beslut för hur de använder Bitcoin men att en andel nyttjar mindre önskade tillvägagångssätt. / Bitcoin has emerged as the most recognizable cryptocurrency since its inception in 2009 and, at the time of writing has a market capitalization of 165 billion dollars. This together with the financial freedom that Bitcoin offers means that the number of users is constantly increasing. Like all new technology, it takes time for the technology to be fully developed and adapted to the wider mass. As a result, security can suffer which can result in financial losses. This research effort explores what measures and strategies can be used to increase safety through a literature study. The effort also investigates with the help of a survey conducted at a Bitcoin forum on how users of Bitcoin manage their private keys. The work shows that there are measures that contribute to increased security such as encryption and multi-signature but that much depends on what the users themselves choose for the type of best strategy for their area of use. The survey shows that the majority of users make security-conscious decisions about how to use Bitcoin but that aproportion uses less desirable approaches.

Physical access control systems (PACS) deal with the security of the availability of resources. They work as an alternative to traditional manual security access control. Access control has two variants, the logical which deals with computer environments and the physical which deals with the physical entry into a property or warehouses. However, offline physical access control systems cannot enforce the user’s path making it unsuitable for use in classified areas, such as places where the public is restricted. Therefore, offline PACS need a framework that can delegate the authority to enforce the user’s path. This is satisfactorily met in the presented research with a new design of offline PACS that has the capability to implement delegation. This framework allows the locks to dynamically write and read access policies onto and from a smart card. It works by means of a construct called “Path Array” and communication among different entities occurs via a chain of trust formed with the use of pre-shared keys.

The amount of data and the development of new technologies used by all society-critical organizations are increasing dramatically. In parallel, data breaches, cyber-attacks, and their devastating consequences are also on the rise, as well as the number of individuals and organizations that are potential targets for such attacks. This places higher demands on security in terms of protecting data against cyber-attacks and controlling access to data that authenticated users want to access. The paper focuses on studying concepts of secure data practices in a GitLab-based cloud environment. The objective is to give answers to questions such as how to ensure the guarantee of secure data and protect it from unauthorized access and changes. The work behind this thesis includes exploring techniques for access control, data encryption, and data immutability. The study is followed by an implementation project that includes fetching code from GitLab verifying user identity and access control, managing data access, and displaying the results. The results of the thesis demonstrate the effectiveness of the implemented security measures in protecting data and controlling access. / Mängden av data och utvecklingen av banbrytande teknologier som idag används av alla samhällsbärande organisationer ökar drastiskt. I samma takt ökar dataintrång, cyberattacker och dess förödande konsekvenser samt antalet personer och organisationer som utgör potentiella offer för sådana typer av attacker. Detta ställer högre krav på säkerheten när det gäller att skydda data mot cyberattacker, men även att kontrollera åtkomsten till data som autentiserade användare vill komma åt. Rapporten fokuserar på att studera hur data säkras i GitLab-baserade molnsystem. Syftet med detta arbete är att ge svar på frågeställningar som till exempel att lova säker åtkomst och skydd för data från obehörig åtkomst och ändringar. Arbetet bakom detta projekt inkluderade undersökning av tekniker som används inom accesskontroll, datakryptering och data-omutlighet. Studien resulterade i en implementation som möjliggör att hämta signerade ändringar (Commits) från GitLab, verifiera användaridentiteten och åtkomstbehörighet, hantera dataåtkomst samt presentera resultaten. Resultaten av detta examensarbete demonstrerar effektiviteten av den implementerade säkerhetsteknikerna i att skydda data och kontrollera access.

The concept of key characteristics deals with the particular moods which different tonalities are believed to provide to music. Discussions regarding their existence and the validity of the phenomena have always been controversial because of a lack of fundamental reasons and explanations for them. Nevertheless, references to key characteristics have appeared in various fields of study and over many centuries: the Greek doctrine of ethos, writings of Guido d’Arezzo, Jean-Philippe Rameau’s Traité de l’harmonie, scribbles in Beethoven’s sketches, and several passages in Hermann von Helmholtz’s On the Sensations of Tones. The attitudes and opinions towards key characteristics have varied in each period of its history. Among the ancient Greeks and Romans, the characteristics of modes were discussed among philosophers, namely, Plato, Aristotle, Lucianus and Cassiodorus. They were believed to affect moral development but were also associated with mysticism. In the Middle Ages and Renaissance, references to key characteristics can be found in the writings of numerous theorists, including Gioseffo Zarlino, Ramos de Pariea and Heinrich Glarean. The studies and discussions of key characteristics in those periods became so well explored as to result in the first appearance of a list of the characteristics of each mode. In Germany and France especially, the discussion of key characteristics reached its peak in the first half of the eighteenth century, when it was studied as a part of Rhetoric. Theorists and composers equally showed their interest in the elements each key could offer to music and how to use keys advantageously in order to enrich the musical experience of the listener. While key characteristics were studied commonly as a vital subject by composers in the eighteenth century and as a fundamental of musical education by many young musicians in the early nineteenth, this tradition had all but disappeared by the middle of the twentieth. The concept of key characteristics is no longer commonly taught in our musical institutions, and this desertion from such a traditionally significant discipline is ever puzzling and particularly interesting to me. In my thesis, I will focus on writings from the last half of the nineteenth century and the first half of the twentieth to determine the various paths taken in the study of key characteristics. I will investigate the writings and discussions of three scholarly groups—music theorists, composers and scientists—from late nineteenth and early twentieth centuries and discuss how the survival of the study of key characteristics was influenced by aspects of the time: popular aspects and aims in the fields of music theory; cultural and social expectations in the validity of phenomena; pronouncements of composers (Arthur Bliss, Alexander Scriabin, Olivier Messiaen, Arnold Schoenberg and Vincent D’Indy) in their musical styles; the rise of a naturalistic view of physical reality as a field and changes it brought to music and societies. I will also include a comparative summary of the status of key characteristics in various periods.

A dataset consisting of logs describing results of tests from a single Build and Test process, used in a Continous Integration setting, is utilized to automate categorization of the logs according to failure types. Two different features are evaluated, words and log keys, using unordered document matrices as document representations to determine the viability of log keys. The experiment uses Multinomial Naive Bayes, MNB, classifiers and multi-class Support Vector Machines, SVM, to establish the performance of the different features. The experiment indicates that log keys are equivalent to using words whilst achieving a great reduction in dictionary size. Three different multi-layer perceptrons are evaluated on the log key document matrices achieving slightly higher cross-validation accuracies than the SVM. A shallow-and-wide Convolutional Neural Network, CNN, is then designed using temporal sequences of log keys as document representations. The top performing model of each model architecture is evaluated on a test set except for the MNB classifiers as the MNB had subpar performance during cross-validation. The test set evaluation indicates that the CNN is superior to the other models. / Ett dataset som består av loggar som beskriver resultat av test från en bygg- och testprocess, använt i en miljö med kontinuerlig integration, används för att automatiskt kategorisera loggar enligt olika feltyper. Två olika sorters indata evalueras, ord och loggnycklar, där icke- ordnade dokumentmatriser används som dokumentrepresentationer för att avgöra loggnycklars användbarhet. Experimentet använder multinomial naiv bayes, MNB, som klassificerare och multiklass-supportvektormaskiner, SVM, för att avgöra prestandan för de olika sorternas indata. Experimentet indikerar att loggnycklar är ekvivalenta med ord medan loggnycklar har mycket mindre ordboksstorlek. Tre olika multi-lager-perceptroner evalueras på loggnyckel-dokumentmatriser och får något högre exakthet i krossvalideringen jämfört med SVM. Ett grunt-och-brett faltningsnätverk, CNN, designas med tidsmässiga sekvenser av loggnycklar som dokumentrepresentationer. De topppresterande modellerna av varje modellarkitektur evalueras på ett testset, utom för MNB-klassificerarna då MNB har dålig prestanda under krossvalidering. Evalueringen av testsetet indikerar att CNN:en är bättre än de andra modellerna.

Recent improvements in genetic analyses have paved the way in using molecular data to answer questions regarding evolutionary history, genetic structure, and demography. Key deer are a federally endangered subspecies assumed to be genetically unique (based on one allozyme study), homogeneous, and have a female-biased population of approximately 900 deer. I used 985bp of the mitochondrial cytochrome b gene and 12 microsatellite loci to test two hypotheses: 1) if the Moser Channel is a barrier to gene flow, I should expect that Key deer are differentiated and have reduced diversity compared to mainland deer and (2) if isolation on islands leads to a higher probability of extinction, I should expect that Key deer exhibit a small population size and a high risk of extinction. My results indicate that Key deer are genetically isolated from mainland white-tailed deer and that there is a lack of genetic substructure between islands. While Key deer exhibit reduced levels of genetic diversity compared to their mainland counterparts, they contain enough diversity of which to uniquely identify individual deer. Based on genetic identification, I estimated a census size of around 1,000 individuals with a heavily skewed female-biased adult sex ratio. Furthermore, I combined genetic and contemporary demographic data to generate a species persistence model of the Key deer. Sensitivity tests within the population viability analysis brought to light the importance of fetal sex ratio and female survival as the primary factors at risk of driving the subspecies to extinction.

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