• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 6
  • 5
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 34
  • 34
  • 6
  • 6
  • 6
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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

Analys av mellanspänningsnätet i centrala delar av Västerås stad / Analysis of the Primary Power Distribution System Located in the City Centre of Västerås

Arvidsson, Mari January 2015 (has links)
The dependency of continuous electricity supply is high in the Swedish society today, at the same time no one is willing to pay for a too costly or over dimensioned power distribution system. The owners of the distribution systems are the ones responsible for this balance act of maintaining a high quality of electricity delivery to customers at a reasonable cost. In this master thesis a limited part of the primary distribution system (10 kV), owned by Mälarenergi Elnät AB and located in the city centre of Västerås, was chosen for a deeper analysis of its reliability. Its ability to handle outages of system components (N-1 and N-2 contingency analysis) was investigated to find out potential weak spots and parts of the grid that showed signs of being overdimensioned. The results of the performed simulations showed that in 74 % of the studied N-1 contingencies cases, consisting of outages of a bus bar in a distribution substation, the system could handle this without causing outages in other parts of the grid. For the N-2 contingencies 61 % passed the test. It was also found that one of the two included high voltage substations could alone supply the investigated part of the grid. Some cables and transformers were found to be more or less unnecessary, whereas other components proved to be overloaded in several situations.
2

Cinemaquinação: entre montanhas e vale, um sobrevoo

Belcavello, Maria Paula Pinto dos Santos 27 March 2017 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-18T11:31:32Z No. of bitstreams: 1 mariapaulapintodossantosbelcavello.pdf: 39674906 bytes, checksum: faa362b8f5e60c046d1491f6398d108c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-18T11:39:21Z (GMT) No. of bitstreams: 1 mariapaulapintodossantosbelcavello.pdf: 39674906 bytes, checksum: faa362b8f5e60c046d1491f6398d108c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-18T11:39:30Z (GMT) No. of bitstreams: 1 mariapaulapintodossantosbelcavello.pdf: 39674906 bytes, checksum: faa362b8f5e60c046d1491f6398d108c (MD5) / Made available in DSpace on 2017-05-18T11:39:30Z (GMT). No. of bitstreams: 1 mariapaulapintodossantosbelcavello.pdf: 39674906 bytes, checksum: faa362b8f5e60c046d1491f6398d108c (MD5) Previous issue date: 2017-03-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho se revela como um exercício cartográfico de experimentação com outros modos de produção de vida, de mundo, de educação. O cinema, a imagem-arte cinematográfica, entra no jogo como dispositivo-disparador de escrita, de leitura e de estar com a pesquisa. Entre uma cena e outra, traça diferentes linhas desta composição. Na indefinição de um método a seguir, um corpo-professor-pesquisador arrisca-se a caminhar no intermezzo da pesquisa, entre acontecimentos. Questões desenham os contornos de um possível mapa: O que se propõe? Cartografar as produções de vida que se reinventam junto ao Mutirão da Meninada do Vale Verde. Experimentar e cartografar as movimentações, os processos de produção de subjetividade e a educação que se faz em um vale. Dar a pensar modos outros de compor uma educação nos diversos territórios existenciais. O que se dispõe? Acompanhar os processos de produção de subjetividade nesse exercício de oficinar com essas vidas que se reinventam no Vale Verde. Capturar os efeitos produzidos com os encontros. O que se compõe? Produção com os afetos e efeitos das vibrações experimentadas junto ao mutirão. Um mapa intensivo de uma viagem experimentada no mesmo e em outros territórios. Um desejo que escapa à procura de respostas. Invenção de problemas! Abrirse ao encontro. Encontrar-se em devir. Experimentar uma educação como acontecimento: processo ético-estético-político. Um sobrevoo, com Deleuze e Guattari, entre montanhas e vale... / This work reveals itself as a cartographic exercise of experimentation with other production modes of life, world, education. The cine, the image-film art, enters the game as a trigger device, reading and writing with the research. Between a scene and another, different lines of this composition. In the blurring of a following method, a body-research professor risk walking in the intermezzo of the survey, between events. Issues draw the contours of a possible map: What do you propose? Mapping the productions of life by the collective effort of reinventing Kids Green Valley. Try and map the drives, the production processes of subjectivity and education that is done in a valley. Give the thinking modes other than compose a education in several existential territories. What offers? Follow the production processes of subjectivity in this oficinar exercise with those lives that reinvent in Green Valley. Capture the effects produced with the dates. What consists? Production with the affects and effects of vibration experienced by the collective effort. A map a journey intensive experienced the same and in other territories. A wish that escapes looking for answers. Invention of problems! Open to date. Find yourself in future. Experience an education event: ethical-aestheticpolitical process. A flypast, with Deleuze and Guattari, between mountains and valley…
3

Kognitiv träning vid depression / Cognitive Training of Depression

Andersson, Ulrika, Persson, Jerry January 2009 (has links)
<p><em><p>Depression är en vida utbredd sjukdom. Kognitiv träning skulle kunna</p><p>vara en kostnadseffektiv och lättillgänglig intervention att bemöta</p><p>sjukdomen i ett tidigt skede. Tidigare forskning tyder på att kognitiv</p><p>träning har effekt på depression och kognitiva nedsättningar. Denna</p><p>studie ämnade undersöka om träning hemma skulle leda till</p><p>förbättringar av depression, och om dessa berodde på träningen i sig.</p><p>Fyra deltagare med depressionssjukdomar genomförde träning med</p><p>Paced Auditory Serial Addition Task (PASAT). Studien hade en n=1-</p><p>design med för- och eftermätningar, och kontroll genom</p><p>pseudointervention. Dagliga och veckovisa mätningar visade</p><p>förbättring för endast en deltagare. Träningen visade sig därmed inte</p><p>effektiv. Tre deltagare upplevde nytta med interventionen. Det kan</p><p>vara skäl för fortsatta studier av kognitiva interventioner vid</p><p>depression.</p></em></p><p> </p> / <p>Depression is a widely spread disorder. Cognitive training could be a</p><p>cost effective and easily accessible intervention to treat the disorder in</p><p>an early stage. Previous research indicates that cognitive training is</p><p>effective in alleviating depression and cognitive deficits. The aim of</p><p>this study was to investigate whether cognitive training at home would</p><p>lead to improvements in depression, and whether improvements were</p><p>due to the training per se. Four subjects with depression participated</p><p>in training with the Paced Audity Serial Addition Task (PASAT). The</p><p>study had an n=1-design with pre- and post-measures, and control by</p><p>a pseudo-intervention. Daily and weekly measures showed effects</p><p>only for one participant. Thus the training was not shown to be</p><p>effective. Three participants experienced benefits from the</p><p>intervention. That could be a reason for further studies of cognitive</p><p>interventions of depression.</p>
4

Kognitiv träning vid depression / Cognitive Training of Depression

Andersson, Ulrika, Persson, Jerry January 2009 (has links)
Depression är en vida utbredd sjukdom. Kognitiv träning skulle kunna vara en kostnadseffektiv och lättillgänglig intervention att bemöta sjukdomen i ett tidigt skede. Tidigare forskning tyder på att kognitiv träning har effekt på depression och kognitiva nedsättningar. Denna studie ämnade undersöka om träning hemma skulle leda till förbättringar av depression, och om dessa berodde på träningen i sig. Fyra deltagare med depressionssjukdomar genomförde träning med Paced Auditory Serial Addition Task (PASAT). Studien hade en n=1- design med för- och eftermätningar, och kontroll genom pseudointervention. Dagliga och veckovisa mätningar visade förbättring för endast en deltagare. Träningen visade sig därmed inte effektiv. Tre deltagare upplevde nytta med interventionen. Det kan vara skäl för fortsatta studier av kognitiva interventioner vid depression. / Depression is a widely spread disorder. Cognitive training could be a cost effective and easily accessible intervention to treat the disorder in an early stage. Previous research indicates that cognitive training is effective in alleviating depression and cognitive deficits. The aim of this study was to investigate whether cognitive training at home would lead to improvements in depression, and whether improvements were due to the training per se. Four subjects with depression participated in training with the Paced Audity Serial Addition Task (PASAT). The study had an n=1-design with pre- and post-measures, and control by a pseudo-intervention. Daily and weekly measures showed effects only for one participant. Thus the training was not shown to be effective. Three participants experienced benefits from the intervention. That could be a reason for further studies of cognitive interventions of depression.
5

Prestanda i ett GraphQL-API : Ett experiment med databaser och verktyg för hantering av N+1-problemet

Martin, Fooladi, Pontus, Åkerberg January 2024 (has links)
Efficient performance is pivotal for digital service and product retention, necessitating consideration and design throughout system development. Central to this is the API, orchestrating communication between client and server within a system. GraphQL, created in 2012, revolutionized this interaction by enabling precise data requests. However, less sophisticated implementations of GraphQL often encounter the N+1 problem, where a query requiring N additional database queries is executed, leading to performance inefficiencies. With increasing data interconnectedness, query complexity and the choice of database management system (DBMS) become critical factors. This study investigates whether a GraphQL API performs better with Neo4j, a graph database, or MariaDB, a relational database, and evaluates how various N+1 problem solving tools influence API performance. The study conducted experiments with six API configurations, each subjected to five queries of varying complexity. One configuration utilized Neo4j, while the remaining five used MariaDB. Among the latter, three configurations integrated N+1 problem solving tools. The study shows that, when query complexity and data interconnectedness is low, response times from a GraphQL API using MariaDB, without solving the N+1-problem, are shorter than the response times of an API using Neo4j. It also demonstrates the efficacy of Neo4j when data becomes more interconnected. Furthermore, the study concludes that addressing the N+1 problem is crucial, and that different tools offer varying levels of performance in solving it. Tools that do manage to solve this issue commonly show a significant improvement in response times when interconnected data is requested. / Effektiv prestanda är avgörande för att behålla användare av digitala tjänster och produkter, och måste tas i beaktande när ett system utvecklas. Centralt i sammanhanget är API:et, som koordinerar kommunikationen mellan klient och server inomett system. GraphQL, som skapades 2012, revolutionerade denna interaktion genomatt möjliggöra exakta dataförfrågningar. Mindre genomtänkta implementationer avGraphQL stöter ofta på N+1-problemet, där en förfrågan som kräver N ytterligare databasförfrågningar utförs, vilket leder till sämre prestanda. Med starkare kopplingar mellan data blir komplexiteten i förfrågningar och valet av databas avgörande faktorer. Denna studie syftar till att utforska om ett GraphQL-API presterar bättre medNeo4j, en grafdatabas, eller MariaDB, en relationsdatabas, och utvärderar hur olika verktyg, som löser N+1-problemet, påverkar API-prestandan. Studien genomförde experiment med sex API-konfigurationer, var och en testad med fem förfrågningar av varierande komplexitet. En konfiguration använde Neo4j, medan övriga fem använde MariaDB. Tre av dessa fem konfigurationer implementerade verktyg för att lösa N+1-problemet. Studien visar att, vid enklare frågor utan kopplad data, kan ett GraphQL-API, som använder MariaDB utan att lösa N+1-problemet, ge mycket kortare svarstider än ett API med Neo4j. Neo4j visar däremot sin effektivitet när data med kopplingar efterfrågas. Vidare visade experimenten på vikten av att lösa N+1-problemet. Verktygen lyckades lösa problemet olika väl, men gemensamt för de verktyg som klarar av att lösa det är att de förbättrar svarstiderna avsevärt så fort kopplad data efterfrågas.
6

A Monte Carlo Study: The Consequences of the Misspecification of the Level-1 Error Structure

Petit-Bois, Merlande 01 January 2014 (has links)
Single-case interventions allow for the repeated measurement of a case or participant across multiple time points, to assess the treatment¡͞s effect on one specific case or participant. The basic interrupted time series design includes two phases: baseline and treatment. Raudenbush and Byrk (2002) demonstrated that a meta-analysis of large group designs can be seen as a special case of multi-level analysis with participants (level-one) nested within studies (level-two). Raw data from a set of single case design studies have a similar structure. Van den Noortgate and Onghena (2003) illustrated the use of a two-level model to analyze data in primary single-case studies. In 2008, Van den Noortgate and Onghena later proposed that if raw data from several single case designs are used in a meta-analysis, scores can be varied at each of the three levels: over occasions (level-one), across participants from the same study (level-two), and across studies (level-three). The multi-level approach allows for a large degree of flexibility in modeling the data (Goldstein & Yang, 2000; Hox & de Leeuw, 1997). Researchers can make various methodological decisions when specifying the model to approximate the data. Those decisions are critical since parameters can be biased if the statistical model is not correctly specified. The first of these decisions is how to model the level-one error structure--is it correlated or uncorrelated? Recently, the investigation of the Van den Noortgate and Onghena¡͞s (2008) three-level meta-analytic model has increased and shown promising results (Owens & Ferron, 2011; Ugille, Moeyaert, Beretvas, Ferron, & Van den Noortgate, 2012 ). These studies have shown the fixed effects tend to be unbiased and the variance components have been problematic across a range of conditions. Based on a thorough literature review, no one has looked at the model in relation to the use of fit indices or log likelihood tests to select an appropriate level-one error structure. The purpose of the study was two-fold: 1) to determine the extent to which the various fit indices can correctly identify the level-one covariance structure; and 2) to investigate the effect of various forms of misspecification of the level-one error structure when using a three-level meta-analytic single-case model. This study used Monte Carlo simulation methods to address the aforementioned research questions. Multiple design, data, and analysis factors were manipulated in this study. The study used a 2x2x2x2x2x5x7 factorial design. Seven experimental variables were manipulated in this study: 1) The number of primary studies per meta-analysis (10 and 30); 2) The number of participants per primary study (4 and 8); 3)The series length per participant (10 and 20); 4)Variances of the error terms (most of the variance at level-one: [¦Ò2=1;¡¼ ¦²¡½_u = 0.5, 0.05, 0.5, 0.05; ¡¼ ¦²¡½_v = 0.5, 0.05, 0.5, 0.05] and most of the variance at the upper levels: [¦Ò2=1;¡¼ ¦²¡½_u = 2, 0.2, 2, 0.2; ¡¼ ¦²¡½_v = 2, 0.2, 2, 0.2]); 5) The levels for the fixed effects (0, 2 [corresponding to the shift in level]; and 0, 0.2[corresponding to the shift in slope]) 6)Various types of covariance structures were used for data generation (ID, AR(1), and ARMA (1,1); and 7) The form of model specification [i.e. ID, AR(1), ARMA (1,1)], and error structure selected by AIC, AICC, BIC, and the LRT. The results of this study found that the fixed effects tend to mostly be unbiased, however, the variance components were extremely biased with particular design factors. The study also concluded that the use of fit indices to select the correct level-1 structure was appropriate for certain error structures. The accuracy of the fit indices tend to increase for the simpler level-one error structures. There were multiple implications for the applied single-case researcher, for the meta-analyst, and for the methodologist. Future research included investigating different estimation methods, such as Bayesian approach, to improve the estimates of the variance components and coupling multiple violations of the error structures, such as non-normality at levels two and three.
7

On the Mechanistic Roles of the Protein Positive Charge Close to the N(1)Flavin Locus in Choline Oxidase

Ghanem, Mahmoud 12 June 2006 (has links)
Choline oxidase catalyzes the oxidation of choline to glycine betaine. This reaction is of considerable medical and biotechnological applications, because the accumulation of glycine betaine in the cytoplasm of many plants and human pathogens enables them to counteract hyperosmotic environments. In this respect, the study of choline oxidase has potential for the development of a therapeutic agent that can specifically inhibit the formation of glycine betaine, and therefore render pathogens more susceptible to conventional treatment. The study of choline oxidase has also potential for the improvement of the stress resistance of plant by introducing an efficient biosynthetic pathway for glycine betaine in genetically engineered economically relevant crop plant. In this study, codA gene encoding for choline oxidase was cloned. The cloned gene was then used to express and purify the wild-type enzyme as well as to prepare selected mutant forms of choline oxidase. In all cases, the resulting enzymes were purified to high levels, allowing for detailed characterizations. The biophysical and biochemical analyses of choline oxidase variants in which the positively charged residue close to the flavin N(1) locus (His466) was removed (H466A) or reversed (H466D) suggest that in choline oxidase, His466 modulates the electrophilicity of the bound flavin and the polarity of the active site, and contributes to the flavinylation process of the covalently bound FAD as well as to the stabilization of the negative charges in the active site. Biochemical, structural, and mechanistic relevant properties of selected flavoproteins with special attention to flavoprotein oxidases, as well as the biotechnological and medical relevance of choline oxidase, are presented in Chapter I. Chapter II summarizes all the experimental techniques used in this study. Chapter III-VII illustrate my studies on choline oxidase, including cloning, expression, purification and preliminary characterizations (Chapter III), spectroscopic and steady state kinetics (Chapter IV), the catalytic roles of His466 and the effects of reversing the protein positive charge close to the flavin N(1) locus (Chapter V and VI), and the roles of His310 with a special attention to its involvement in a proton-transfer network (Chapter VII). Chapter VIII presents a general discussion of the data presented.
8

The cybernetics of nonzero sum games : the prisoner's dilemma reinterpreted as a pure conflict game with nature, with empirical applications

Bell, Robert I. January 1972 (has links)
In this thesis a new solution concept is developed for n-player, nonzero sum games. The solution concept is based in reinterpreting the n-player nonzero sum game into 2-player zero sum games. The n-player nonzero sum game is first rewritten as an n + 1 player coalition game. The definition of zero sum payment is that one player pays the other what he gets in a given outcome (coalition of the n + 1 player game). Who pays whom depends on the coalition. More than one 2-player zero sum interpretation game always results from the procedure, and criteria are established to select one of the zero sum interpretation games. The solution concept defines results identical to the minimax concept when applied directly to zero sum 2-player games. When applied to 2-player prisoner’s dilemma games, the solution procedure assigns mixed strategies to the prisoners, thereby “resolving” the dilemma. The mixed strategies vary with the payoffs (up to a linear transformation). For prisoner’s dilemma matrices which have been used in large numbers of gaming experiments, the solution concept predicts dynamically, i.e., by play number, the “fraction of cooperative choices” for (approximately) the first 30 plays. In addition, the mixed strategy appears in a game between each subject (prisoner) and the n + 1st player (district attorney), suggesting that the subjects have been playing against the experimenter. Empirical evidence for this conclusion is given. A theorem is proved for n-player prisoner’s dilemma games. Game theory is reviewed to show the roots of this solution concept in the heuristic use of zero sum n-player games in the von Neumann and Morgenstern theory, and in rational decision making models, e.g., “games against Nature.” The empirical and formal difficulties of the equilibrium point solution concept for nonzero sum games are discussed. Detailed connections between game theory and cybernetics are discussed.
9

Efectos de los liceos públicos emblemáticos sobre el desempeño escolar el caso del Liceo N.1 de Niñas Javiera Carrera

Manríquez, Bárbara 04 1900 (has links)
Tesis para optar al grado de Magíster en Análisis Económico / En un contexto de debate sobre las reformas que afectarán los mecanismos de selección académica de los colegios públicos emblemáticos, este trabajo presenta evidencia del impacto sobre el desempeño académico de asistir a un liceo público, selectivo y de excelencia. Particularmente, se analiza el caso del Liceo N°1 “Javiera Carrera”. La metodología consiste en un diseño de regresión discontinua fuzzy. Utilizando datos administrativos proporcionados por el Liceo N°1 y datos del Sistema de Medición de la Calidad de la Educación (evaluación Simce), se comparan los resultados de estudiantes que son similares al momento de postular al establecimiento, pero que difieren en haber ingresado o no al Liceo N°1. Los resultados sugieren que, a pesar que los test de medias son favorables para las estudiantes del establecimiento, haber asistido al Liceo N°1 no posee un efecto LATE (Local Average Treatmente Effect) estadísticamente significativo sobre el promedio Simce de lectura y matemática de 2do medio. Por otro lado, al analizar el efecto sobre las estudiantes de 8vo básico, quienes llevaban dos años en el establecimiento, tampoco se aprecia un efecto significativo de participar en el colegio, e incluso en algunas especificaciones este efecto es negativo, sin embargo esto podría ser poco conclusivo al verse influenciado por el proceso de adaptación a un nuevo establecimiento de alta exigencia académica.
10

Síntese de novos derivados de 1-(7-cloro-4-quinolinil) tiossemicarbazidas e semicarbazidas como potencias agentes antibacterianos e antiparasitários

Machado, Rafael Carvalhaes 18 July 2011 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-27T12:08:52Z No. of bitstreams: 1 rafaelcarvalhaesmachado.pdf: 4567959 bytes, checksum: d476d2158bd5cb7ad61d6470ecca1cee (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-13T13:00:19Z (GMT) No. of bitstreams: 1 rafaelcarvalhaesmachado.pdf: 4567959 bytes, checksum: d476d2158bd5cb7ad61d6470ecca1cee (MD5) / Made available in DSpace on 2017-05-13T13:00:19Z (GMT). No. of bitstreams: 1 rafaelcarvalhaesmachado.pdf: 4567959 bytes, checksum: d476d2158bd5cb7ad61d6470ecca1cee (MD5) Previous issue date: 2011-07-18 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A presente dissertação, intitulada Síntese de novos derivados de 1-(7-cloro-4-quinolinil) tiossemicarbazidas e semicarbazidas como potencias agentes antibacterianos e antiparasitários descreve a síntese de novos derivados de 1-(7-cloro-4-quinolinil) tiossemicarbazidas e semicarbazidas N-1-substituídas além dos respectivos derivados piridínicos como potenciais agentes antibacterianos e antiparasitários. A síntese destes derivados procedeu-se via substituição nucleofílica aromática (SNAr) entre a 4,7-dicloroquinolina ou o cloridrato de 4-cloropiridina com as tiossemicarbazidas e semicarbazidas N-substituídas. As tiossemicarbazidas e semicarbazidas foram preparadas a partir da redução das respectivas tiossemicarbazonas e semicarbazonas com amalgama de sódio. Os resultados da avaliação biológica dos derivados 1-(7-cloro-4quinolinil)tiossemicarbazidas, semicarbazidas e 1-(4-piridinil)tiossemicarbazidas contra a bactéria Mycobacterium tuberculosis também são discutidos. / This work, entitled “Synthesis of novel derivatives of 1-(7-chloro-4-quinolinyl) thiosemicarbazides and semicarbazides as potencial antibacterial and antiparasitic agents” describes the synthesis of new derivatives of 1-(7-chloro-4-quinolinyl) thiosemicarbazides and semicarbazides, N-1-substituted pyridine derivatives were also prepared and their evaluation as potential antibacterial and antiparasitic agents was investigated. The synthesis of these compounds proceeded via nucleophilic aromatic substitution (SNAr) 4,7-dichloroquinoline or 4-chloropyridine hydrochloride by Nsubstituted thiosemicarbazides and semicarbazides. The thiosemicarbazides and semicarbazides were prepared by reduction of the respective thiosemicarbazones and semicarbazones with sodium amalgam. The results of biological evaluation of these 1-(7-chloro-4- quinolinyl)thiosemicarbazides, semicarbazides and 1-(4-pyridinyl)thiosemicarbazides against the bacterium Mycobacterium tuberculosis are also discussed.

Page generated in 0.046 seconds