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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

A decision support system for conduct hydropower development

Loots, Ione January 2013 (has links)
Cheap and reliable electricity is an essential stimulus for economic and social development. Currently fossil fuels are used for the majority of global electricity generation, but energy shortages and pressure on all industries to reduce CO2 emissions provide incentives for growing emphasis on the development of alternative energy-generation methods. Presently hydropower contributes about 17% of global energy generation, which is only a fraction of its total potential. In Africa only 5% of its estimated hydropower potential has been exploited, making it the most underdeveloped continent in terms of hydropower. An often overlooked source of hydropower energy is found in conduits, where pressure-reducing stations (PRSs) are installed to dissipate excess energy. The energy dissipated by these devices can instead be captured as hydroelectricity if turbines are installed in the conduits, either by replacing pressure-reducing valves (PRVs) with a turbine, or by installing the turbine in parallel with the PRV. An initial scoping investigation indicated that significant potential exists for small-scale hydropower installations in water-distribution systems in South Africa. Almost all of the country’s municipalities and water-supply utilities have pressure-dissipating stations in their water-distribution systems, where hydropower potential may exist. This dissertation reflects the development of a Conduit Hydropower Decision Support System (CHDSS), summarised in a series of flow diagrams that illustrate the developmental process (Figure i(a) provides an example). A Conduit Hydropower Development (CHD) Tool was developed to facilitate the calculation of necessary factors (the Phase 1 Economic Analysis is shown in Figure i(b)). The objective of this CHDSS was to assist municipalities and engineers in identifying conduit hydropower potential in South Africa and to provide proper guidance for the development of potential sites. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Civil Engineering / Unrestricted
2

Vienetų testų generavimo metodo Android aplikacijoms testuoti realizavimas ir tyrimas / Implementation and research of unit tests generation method for testing Android applications

Babenskas, Egidijus 31 October 2013 (has links)
Tobulėjant išmaniesiems telefonams ir jų techninėms galimybėms bei didėjant jų pardavimams Lietuvoje ir pasaulyje, kuriamos aplikacijos tampa sudėtingesnės ir funkcionalesnės, tačiau kokybės problema vis dar išlieka skaudžia programinės įrangos kūrimo dalimi. Šiuo metu iš visų parduodamų išmaniųjų telefonų apie 50% parduodami su Android operacine sistema. Matant Android OS programų vis didėjantį poreikį rinkoje ir jų populiarumą bei panagrinėjus esamą rinką ir pamačius, jog testavimo įrankių, skirtų testuoti Android aplikacijas, beveik nėra, buvo nuspręsta, jog reikalingas vienetų testų generavimo sprendimas pritaikytas testuoti Android aplikacijas. Šio darbo pagrindinis tikslas ir yra pateikti vienetų testų generavimo sprendimą skirtą Android OS aplikacijos testuoti, jį realizuoti bei pagrįsti eksperimentiškai. Darbe siūlomas vienetų testų generavimo metodas, kuris remiasi atsitiktiniu generavimu, naudoja OCL apribojimus bei regresinio testavimo principus. Taip pat yra suderinamas su Google kompanijos teikiamu ADT įskiepiu ir Android SDK priemonėmis. Įrankis sukurtas kaip Eclipse programavimo aplinkos įskiepis. Pasiūlyto vienetų testų generavimo sprendimo efektyvumas įrodomas eksperimentiniu tyrimu. Šio eksperimento metu buvo testuojamos 4 aplikacijos. Naudojantis įrankiu vidutiniškai sugautų mutantų skaičius yra 75%. Mažiausia reikšmė yra 69%, o didžiausia – 88%. Vidutiniškai pasiekiamas 85% kodo eilučių padengimas. Mažiausia reikšmė yra 72%, o didžiausia padengimo... [toliau žr. visą tekstą] / With the development of smart phones and their technical capabilities and increase of their sales in Lithuania and the world applications become more complex and have more functionality, but the issue of quality remains a painful part of the development of software. Currently 50% out of all smart phones are sold with Android operating system. Having an increasing demand and popularity of Android OS applications in the market, as well as having researched the current market and seen that there is a lack of testing tools to test Android applications, it has been decided that a solution generating unit tests is needed to test Android applications. The main goal of this work is to provide unit test generation solution for the Android OS application testing, implementation and validate it experimentally. This work proposes a method generating unit tests based on random generation, using OCL constraints and regression testing principles. It is compatible with Google plug-in ADT and Android SDK tools. The tool is designed as a plugin in Eclipse development environment. Efficiency of the proposed decision of generating unit tests is proved by experimental study. During this study four applications were tested. Using the tool the average of catched mutants is 75%. The minimum value is 69%, while the highest - 88%. On average coverage of code lines is achieved by 85%. The minimum value is 72% and the maximum value of coverage - 97%.
3

Estudo de métodos para a dispersão de nanopartículas de níquel e ferro em suspensão

Zoccal, João Victor Marques 27 April 2015 (has links)
Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-09-30T18:32:13Z No. of bitstreams: 1 TeseJVMZ.pdf: 2731888 bytes, checksum: a756e69d141b297fb91ca74654baab0d (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-09-30T19:17:40Z (GMT) No. of bitstreams: 1 TeseJVMZ.pdf: 2731888 bytes, checksum: a756e69d141b297fb91ca74654baab0d (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-09-30T19:17:49Z (GMT) No. of bitstreams: 1 TeseJVMZ.pdf: 2731888 bytes, checksum: a756e69d141b297fb91ca74654baab0d (MD5) / Made available in DSpace on 2016-09-30T19:25:18Z (GMT). No. of bitstreams: 1 TeseJVMZ.pdf: 2731888 bytes, checksum: a756e69d141b297fb91ca74654baab0d (MD5) Previous issue date: 2015-04-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / In recent decades, several studies have been conducted on the generation of materials at the nanoscale, not only by offering possible risks when inhaled, but also by the various applications that can be employed. Among the various equipment used for the generation of particles, atomizers generators have proved efficient and economical. Although many studies have used materials in solution, in which the material is dissolved in the solvent, generation of particles, it has been observed growing interest in the study of suspended nanometric materials, in which there is dispersion in the solvent. In addition, this growing interest in the suspended study materials is due to the need to generate solid aerosols from oxides, since they have high added value and important to be recaptured and intended back into production. Given the presented work aimed to disperse nanoparticles from suspensions, evaluating the time of the generation process over a period of 10 hours, for different equipment. The nanoparticles were generated by atomization of nickel and iron oxides suspensions at different concentrations and the atomization process were used three generator, a generator from TSI, model 3079, a commercial inhaler of the brand NS, model I-205 and a fluidized bed generator, model 3400. The size distribution and concentration of particles was determined by a Scanning Mobility Particle Sizer (SMPS), Model 3936 and a Aerodynamic Particle Sizer (APS), Model 3320, both from TSI, being sampled directly from the aerosol. The results relating to the dispersion of nanoparticles from the suspension of nickel and iron oxide proved effective in 10 hour period. However, TSI generator showed a dispersion of particles with a more uniform distribution, whereas the commercial inhaler dispersed a greater number of particles per cm3. In addition, the collection of particles by APS, there was the generation of micrometric particles, since the particles are already being generated aglomeradamente, which was observed in SEM and TEM images. / Nas últimas décadas, diversos estudos têm sido realizados sobre a geração de materiais na escala nanométrica, não só pelos possíveis riscos que oferecem quando inalados, mas também pelas diversas aplicações que podem ser empregados. Dentre os diversos equipamentos utilizados para a geração de partículas, os geradores atomizadores têm-se demonstrado eficientes e econômicos. Embora muitos trabalhos têm utilizado materiais em solução, na qual o material fica dissolvido no solvente, na geração de partículas, tem-se observado o crescente interesse de estudos sobre materiais nanométricos suspensos, nas quais não se dissolvem no solvente, mas sim se dispersão no meio. Em adição, este crescente interesse no estudo de materiais em suspensão é decorrente da necessidade de se gerar aerossóis sólidos provenientes de óxidos, uma vez que apresentam alto valor agregado, sendo importante ser recapturados e destinados de volta à produção. Diante do apresentado, o trabalho visou dispersar nanopartículas provenientes de suspensões, avaliando o tempo do processo de geração ao longo de um período de 10 horas, por diferentes equipamentos. As nanopartículas foram geradas através da atomização de suspensões de óxido de níquel e ferro em diferentes concentrações e no processo de atomização foram utilizados três geradores, um gerador da TSI, modelo 3079, um inalador comercial da marca NS, modelo I-205 e um gerador de leito fluidizado, modelo 3400. A distribuição de tamanho e concentração das partículas foram determinadas por meio de um Analisador de Partículas por Mobilidade Elétrica (SMPS), modelo 3936 e pelo Contador de Partículas (APS), modelo 3320, ambos da TSI, sendo a amostragem feita diretamente do aerossol. Os resultados referentes à dispersão das nanopartículas provenientes das suspensões de óxido de níquel e de ferro mostraram eficientes no período de 10 horas. No entanto, o gerador da TSI apresentou uma dispersão de partículas com uma distribuição mais uniforme, enquanto que o inalador comercial dispersou um maior número de partículas por cm3. Em adição, na coleta de partículas pelo APS, teve-se a geração de partículas micrométricas, uma vez que as partículas já estavam sendo geradas aglomeradamente, fato que foi observado nas imagens de MEV e MET.
4

Integrability in two-dimensional gravity

Katsimpouri, Despoina 07 September 2015 (has links)
In dieser Arbeit untersuchen wir Gravitations- und Supergravitationssysteme, die in zwei Dimensionen vollständig integrabel sind. Dies sind Theorien, zu denen auch die einsteinsche Gravitation zählt, die bei dimensionaler Reduktion auf drei Dimensionen, die Form eines nichtlinearen $\s$-Models für den Materieteil annehmen und als Zielmannigfaltigkeit den Cosetraum $\mathrm{G}/\mathrm{K}$ haben. Ausgehend von der einsteinschen Gravitation betrachten wir insbesondere die Klasse der stationären und axialsymmetrischen Lösungen. Dabei untersuchen wir das lineare System (Lax-Paar), das den nichtlinearen Feldgleichungen der Vakuumsgravitation entspricht, wie es von Belinski-Zakharov (BZ) und Breitenlohner-Maison (BM) formuliert wurde. Die Existenz des linearen Systems zeigt die Integrabilität des zweidimensionalen Systems und ist inversen Streumethoden zugänglich, wie in zwei unterschiedlichen Ansätzen von BZ und BM gezeigt. Aus der unendlich-dimensionalen Symmetrie, die mit den zweidimensionalen Gleichungen assoziiert ist, ergibt sich die sogenannte Gerochgruppe. Der BM-Ansatz ermöglicht eine direkte Implementierung der Gerochgruppe und der Erzeugung von physikalisch interessanten Lösungen im Solitonensektor auf manifest gruppentheoretischer Weise. Aus diesem Grund ist zu erwarten, dass es in einem breiteren Spektrum von Cosetmodellen angewendet werden kann. In dieser Arbeit konzentrieren wir uns auf diesen Ansatz und erweitern ihn um die STU-Supergravitation, wobei entsprechende technische Änderungen im BM-Lösungserzeugungsalgorithmus erforderlich werden. Basierend auf diesen Änderungen, diskutieren wir auch eine Verallgemeinerung auf andere Fälle. Wir testen die Anwendbarkeit der BM inversen Streumethode, indem wir explizit folgende Lösungen konstruieren: die Kerr-NUT Lösung der einsteinschen Gravitation, die Vier-Ladungs-Lösung eines schwarzen Lochs innerhalb der STU Supergravitation von Cvetic und Youm und die einfach rotierende JMaRT Lösung. / In this thesis, we study gravity and supergravity systems that become completely integrable in two dimensions. Including Einstein gravity, these systems are theories that upon dimensional reduction to three dimensions assume the form of a non-linear $\s$-model for the matter part, with target manifold a coset space $\mathrm{G}/\mathrm{K}$. Starting from Einstein gravity and focusing on the class of stationary axisymmetric solutions, we study the linear system (Lax pair) associated with the non-linear field equations of vacuum gravity as formulated by Belinski - Zakharov (BZ) and Breitenlohner-Maison (BM). The existence of the linear system exhibits the integrability of the two-dimensional system and is amenable to inverse scattering methods as shown in two different approaches by BZ and BM. The infinite dimensional symmetry associated with the two-dimensional equations gives rise to the so-called Geroch group. The BM approach allows for a direct implementation of the Geroch group and the generation of physically interesting solutions in the soliton sector in a manifestly group theoretic way. For this reason, it is expected to apply to a broader set of coset models. Throughout this work, we concentrate on this approach and extend it to STU supergravity, where appropriate technical modifications were required in the BM solution generation algorithm. Based on these modifications, we also discuss a generalization to other set-ups. We test the applicability of the BM inverse scattering method by explicitly constructing the Kerr-NUT solution of Einstein gravity and within STU supergravity, the four-charge black hole solution of Cvetic and Youm as well as the singly rotating JMaRT solution.

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