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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.
71

Investigação de operadores essenciais de mutação para programas orientados a aspectos

Lacerda, Jésus Thiago Sousa 20 October 2014 (has links)
Made available in DSpace on 2016-06-02T19:06:18Z (GMT). No. of bitstreams: 1 6398.pdf: 1432485 bytes, checksum: dbb2a36cf46b2e3c828fe5dd53dc5d1a (MD5) Previous issue date: 2014-10-20 / Financiadora de Estudos e Projetos / Context: The literature on software testing reports on the application of the Mutation Analysis criterion or mutation testing as a promising approach for revealing faults in aspect-oriented (AO) programs. However, it is widely known that this criterion is highly costly due to the large number of generated mutants and the effort required to identify equivalent mutants. We highlight that little existing research on mutation testing for AO programs focuses on cost reduction strategies. Objective: this work aims at investigating the cost reduction of mutation testing for AO programs. In particular, we intend to reduce the cost of mutation testing by identifying a reduced set of mutation operators that are capable of keeping the effectiveness in guaranteeing the quality of the designed test sets. Method: to achieve the goals, we applied an approach called Sufficient Procedure. Such approach yields sufficient (sets of) mutation operators. Test sets that are adequate with respect to mutants produced by sufficient operators are able to reveal the majority of faults simulated by a whole set of mutants. Results: by applying the Sufficient Procedure, we obtained substantial cost reductions for three groups of AO programs. The cost reduction in the experiments range from 52% to 62%. The final mutation scores yielded by the test sets that are adequate to mutants produced by the sufficient operators range from 92% to 94%. Conclusion: with the achieved results, we conclude that it is possible to reduce the cost of mutation testing applied to AO programs without significant losses with respect to the capacity of revealing prespecified fault types. The Sufficient Procedure has shown to be able to support cost reduction and to maintain the effectiveness of the criterion. / Contexto: A literatura de teste de software relata a aplicação do critério Análise de Mutantes ou teste de mutação em programas orientados a aspectos (OA) como uma forma promissora para revelar defeitos. Entretanto, esse critério é reconhecidamente de alto custo devido ao grande número de mutantes usualmente gerados e ao esforço para detectar os mutantes equivalentes. Ressalta-se que as iniciativas de aplicação de teste de mutação nesse contexto apresentam pouco enfoque em estratégias de redução de custo. Objetivo: este trabalho tem como objetivo investigar a redução de custo de teste de mutação para programas OA. Em específico, este trabalho objetiva reduzir o custo do teste de mutação por meio da identificação de um conjunto reduzido de operadores de mutação que mantenham a efetividade do critério em garantir a qualidade dos conjuntos de teste produzidos. Metodologia: para atingir o objetivo proposto, aplicou-se uma abordagem intitulada Procedimento Essencial, a qual resulta em conjuntos de operadores essenciais de mutação. Os testes adequados para os mutantes produzidos com esses operadores são capazes de revelar a maioria dos defeitos simulados em um conjunto completo de mutantes. Resultados: por meio da aplicação do Procedimento Essencial, foi possível obter reduções de custo substanciais para três conjuntos de programas OA. As reduções obtidas nos experimentos variam de 52% a 62%. Os escores de mutação finais alcançados pelos testes adequados aos mutantes produzidos com os operadores essenciais variam de 92% a 94%. Conclusão: com os resultados alcançados neste trabalho pode-se afirmar que é possível reduzir o custo do teste de mutação em programas OA sem perdas significativas na capacidade de revelar tipos de defeitos pré-definidos. O Procedimento Essencial mostrou-se eficaz na redução de custo e na manutenção da efetividade do critério.
72

Aplicação de fibra de ervilha em produtos cárneos / Pea fiber applied in meat products

Yana Jorge Polizer Rocha 26 February 2015 (has links)
O presente trabalho teve como objetivo avaliar as características físico-químicas e de aceitação sensorial de diferentes produtos cárneos elaborados com adição de fibra de ervilha como substituto parcial de carne (visando redução de custos no produto) e de gordura (visando a elaboração de um produto mais saudável). Foram processados quatro diferentes produtos cárneos (nuggets, hambúrguer, apresuntado e salsicha), onde cada um apresentou as seguintes formulações: nuggets (Nuggets Controle (NC) - formulação semelhante à comercial, Nuggets Fibra/ Menos Carne (NFMC) - redução de 10% de carne e adição de 2 % de fibra de ervilha e Nuggets Fibra/ Menos Gordura (NFMG) - redução de 10 % de gordura e adição de 2% de fibra de ervilha), hambúrguer (Hambúrguer Controle (HC) - semelhante à formulação comercial; Hambúrguer Fibra/ Menos Carne (HFMC) - redução de 5% de carne e adição de 1 % de fibra de ervilha e Hambúrguer Fibra/ Menos Gordura (FMG) - redução de 7 % de gordura e adição de 1,0 % de fibra de ervilha), apresuntado (Apresuntado Controle (AC) - semelhante à formulação comercial e Apresuntado Fibra/Menos Carne (AFMC) - redução de 5% de carne e adição de 1% de fibra) e salsicha: (Salsicha Controle (SC) - semelhante à formulação comercial; Salsicha Fibra/Menos Carne (SFMC): redução de 5% de carne bovina e adição de 2% de fibra de ervilha e Salsicha Fibra/ Menos Gordura (SFMG) - redução de 7 % de gordura e adição de 2,0 % de fibra de ervilha). Após o processamento os produtos foram caracterizados quanto à composição centesimal, cor objetiva, perfil de textura, perda de peso após a fritura (nuggets), perda de peso por cocção (hambúrguer), redução do diâmetro (hambúrguer), perdas por gotejamento (apresuntado), rendimento do produto (salsicha), estabilidade da emulsão (salsicha) e avaliação sensorial (teste de aceitação com escala hedônica de nove pontos). Para os nuggets as formulações NFMC e NFMG apresentaram pH superior (p<0,05) ao controle, e a formulação NFMG apresentou maior (p<0,05) dureza, quanto à porcentagem de perdas após a fritura, os parâmetros elasticidade e coesividade e a avaliação sensorial não foram encontradas diferenças (p>0,05) entre as formulações. A aplicação de fibra de ervilha e redução de carne e gordura nos hambúrgueres não afetaram (p>0,05) os valor de pH, parâmetros de cor L* e b*, os parâmetros avaliados no perfil de textura, perdas de peso por cocção, redução do tamanho (encolhimento) e avaliação sensorial, apenas a formulação HFMC apresentou redução (p<0,05) no parâmetro a*. Quanto ao apresuntado, os parâmetros de dureza e mastigabilidade foram maiores (p<0,05) para a formulação AC, a formulação AFMC apresentou valor de L* superior (p<0,05), parâmetros de cor a* e b* inferiores (p<0,05) ao C e maior aceitação geral, já o valores de pH, perdas por gotejamento e as médias dos demais atributos sensoriais avaliados não apresentaram diferença (p>0,05) entre as formulações. Em relação aos resultados obtidos na salsicha, a formulação SFMG apresentou pH inferior (p<0,05) a SC e maior valor para os parâmetros de dureza e mastigabilidade. As formulações SFMC e SFMG apresentaram rendimento inferior (p<0,05) a SC e não diferiram quanto à estabilidade da emulsão, já em relação a avaliação sensorial formulação SFMC apresentou notas superiores (p<0,05) à formulação SC e SFMG quanto aos atributos textura, sabor e aceitabilidade geral. De acordo com os resultados obtidos pode-se concluir que a fibra de ervilha mostrou-se como um ingrediente promissor para aplicação em produtos cárneos, já que nas condições testadas a substituição parcial de carne e gordura por fibra de ervilha não ocasionou prejuízo na maioria dos parâmetros físico-químicos avaliados e não prejudicou a aceitação sensorial em nenhum dos produtos cárneos estudados. / The objective of this study was to characterize physicochemical aspects of meat products and their sensorial acceptance elaborated with the addition of pea fiber as a partial substitute of meat (aiming the product cost reduction), and fat (aiming a healthier product). Four different meat products were formulated and processed (chicken nuggets, burger, chopped ham and frankfurter), as follows: chicken nuggets (Nuggets Control (NC) - formulation similar to the commercial product, Nuggets Fiber Less Meat (NFLM) - 10% of meat reduction and 2% of pea fiber addition, and Nuggets Fiber Less Fat (NFLF) - 10% of fat reduction, and 2% of pea fiber addition), burger (Burger Control (HC) - similar to the commercial formulation; Burger Fiber Less Meat (BFLM) - 5% of meat reduction, and 1% of pea fiber addition, and Burger Fiber Less Fat (BFLF) - 7% of fat reduction, and 1% of pea fiber addition); chopped ham (Chopped Ham Control (CHC) - similar to the commercial formulation, and Chopped Ham Fiber Less Meat (CHFLM) - 5% of meat reduction, and 1% of pea fiber addition), chopped ham (Chopped Ham Control (CHC) - similar to the commercial formulation, and Chopped Ham Fiber Less Meat (CHFLM) - 5% of meat reduction, and 1% of pea fiber addition), and frankfurter: ( Frankfurter Control (FC) - similar to the commercial formulation; frankfurter Fiber Less Meat (FFLM): 5% of beef reduction, and 2% pea fiber addition, and Frankfurter Fiber Less Fat (FFLF) - 7% of fat reduction, and 1% of pea fiber addition). After processing the products were characterized concerning proximal composition, color determination, texture, weight loss after frying (chicken nuggets), weight loss after cooking (burger), diameter reduction (burger), drip loss (chopped ham), product outcome (frankfurter), emulsion stability (frankfurter) and sensory analysis (nine point hedonic scale acceptance test). For the nuggets NFLM and NFLF formulations presented higher levels of pH (p<0.05) compared to control, and NFLF formulation presented higher (p<0.05) firmness. Regarding the losses after frying, the elasticity parameters, and cohesiveness and sensory analysis were not different (p>0.05) among formulations. The pea fiber addition and meat and fat reduction in burgers did not affect (p>0.05) the pH levels, color parameters L* and b*; the analyzed parameters concerning texture, weight loss after cooking, diameter reduction (shrinking), and sensory analysis, only BFLM formulation presented reduction (p<0.05) in the parameter a*. Regarding the chopped ham, firmness and chewiness parameters were higher (p<0.05) compared to CHC formulation, CHFLM formulation presented higher L* levels (p<0.05), lower parameters of color a* and b* (p<0.05) compared to CHC and higher general acceptance, yet the pH levels, drip loss and the averages of the other sensory characteristics analyzed did not present difference (p>0.05) among formulations. Regarding the results obtained with the frankfurter, the FFLF formulation presented lower pH levels (p<0.05) compared to FC and higher values for firmness and chewiness parameters, FFLM and FFLF formulations presented lower outcome (p<0.05) compared to FC and were not different to the emulsion stability, however regarding the sensory analysis FFLM formulation presented higher values (p<0.05) compared to FC and FFLF concerning texture, flavor and general acceptance. According to the results it is concluded that pea fiber is a promising ingredient to be added in meat products, since the tested conditions in the partial substitution of meat and fat for pea fiber did not cause significant change in most analyzed physicochemical parameters and did not interfere the sensory acceptance in any of the studied meat products.
73

Sistema de preparo profundo do solo e sua influência no desenvolvimento da cana-de-açúcar / Deep soil preparation system and its influence on sugarcane development

Halan Vieira de Queiroz Tomaz 21 January 2014 (has links)
A cana-de-açúcar é uma das mais importantes cadeias do agronegócio brasileiro, além do seu elevado destaque no contexto internacional como fonte de energia renovável e sustentável. Com a competitividade que as Usinas vem passando e pelas perspectivas de crescimento, este trabalho teve como hipóteses: i) o preparo profundo em cana-de-açúcar proporciona um maior volume de solo explorado pelas raízes; ii) o trafégo controlado de máquinas aliado ao espaçamento em fileiras duplas irá trazer uma maior população de plantas, traduzindo isso em incrementos de produtividade e redução de custos para o produtor. O objetivo geral, portanto, foi avaliar métodos de preparo do solo e desenvolver o tráfego contrololado na área, propondo assim que o produtor tenha redução nos custos com o manejo da cultura e também aumente a produtividade e longevidade do canavial. Portanto, pode-se concluir que na análise do comprimento de raízes, em todas as profundidades estudadas, o Preparo Profundo obteve comprimento, área e volume de raízes maiores estatisticamente. A Resistência do solo a penetração no tratamento Preparo Profundo, para as profundidades de 20-40 e 40-60 cm foi de 0,29 MPa e 0,45 MPa, respectivamente. Nas avaliações biométricas da parte área, o Preparo Profundo se destacou com um IAF de 7,1. Os custos das operações no momento do plantio foram bem inferiores no Preparo Profundo, sendo 33% e 58% inferiores aos Mínimo duplo e Convencional duplo, respectivamente. A movimentação do solo causada pelo sistema Preparo Profundo no preparo do solo, foi de até 80% inferior ao tratamento Convencional duplo. O tráfego controlado que o Preparo Profundo proporciona, diminui em até 70% o tráfego de máquinas na lavoura; menor consumo de combustível; redução no tempo das operações agrícolas; redução do parque de máquinas; e menor custo operacional. / Sugarcane is one of the most important crops in the Brazilian agribusiness chain, besides its great branch in the international context as a renewable and sustainable energy source. Through the competitiveness that sugar mills experience and through the growth perspectives of the sector, this study focuses the deep soil preparation for sugarcane crop renewal, since it provides a larger soil volume to be explored by the root system. Furthermore, the machinery traffic controlled by a smaller number of soil preparation operations, reduces farmer´s production costs. The general objective was, therefore, evaluate soil preparation methods and develop a controlled traffic system in the area, in order to propose to the farmer a cost reduction in the farm soil management along with yield increase and extension of the longevity of the crop. As a result of the imposed treatments it was possible to conclude that by the root length analysis in all depths of the Deep Soil Preparation, root length, area and volume were greater. Soil resistance to penetration in the Deep Soil Preparation system was much less in relation to the other treatments, assuming values of 0.29 MPa and 0.45 Mpa in the 20-40 and 40-60 cm layers, respectively. The above ground evaluations showed leaf area index of 7.1 for the Deep Soil Preparation, much higher in relation to the other treatments. Operation costs at planting time were much less for the Deep Soil Preparation, 33% and 58% smaller than for the Double Minimum Tillage and Double conventional, respectively. Soil movement caused by Deep Preparation was up to 80% less in relation to the Double conventional. The controlled machinery traffic that the Deep Soil Preparation provides, reduced up to 70% the farming operations, therefore presenting a lower fuel consumption, a reduction of the time used in farming operations, reduction of the machinery park, and a lower operational cost.
74

Využití informačních technologií pro manažerské sledování efektivity času a minimalizaci nákladů / Information technologies enabling managerial time tracking and cost reduction

Dědek, Lubomír January 2008 (has links)
Time tracking means to record and analyze costs in relation with business output. Managerial time tracking can be characterized as a tool that links working-time recording with planning, approving, rating, billing, invoicing, etc. This thesis deals with theoretical consequences and facts of time tracking approaches, and with practical application of these approaches with the usage of IT time tracking tools. There are described various alternatives of time tracking systems and characterized automatization of business processes with the focus on time tracking business process.
75

Etablering av lågtempererad fjärrvärme : Utveckling och tillämpning av ett indikatorsystem / Establishment of low-temperature district heating : Development and application of an indicator system

Vanky, Katarina January 2022 (has links)
This master thesis aims to develop an assessment tool for decision-making regarding future establishment of low-temperature district heating (LTDH). The tool is created as an indicator system on behalf of Södertörns Fjärrvärme AB (SFAB). SFAB is currently responsible for the distribution of high-temperature district heating (HTDH) to customers in the municipalities of Huddinge, Botkyrka, and Salem. The indicator system is designed to, in a first assessment step, examine the conditions that a delimited area has for conversion to lower system temperatures to be possible. Each indicator is quantified and graded. When using the system, a weighted final judgement is generated which indicates whether an area is suitable for LTDH or not. Furthermore, the purpose of this thesis is to also evaluate the tool by applying it to various areas within SFAB. This enables analysis and discussion regarding the tool's function in a real context. The development of the indicator system is the main result of the study. It consists of four indicators that take the following aspects into account: qualitative conditions (KA), conditions on the customer side (AA), the economic benefit (CRG), and the system condition (STA). The results from the implementation show that one out of five case-areas have good potential to be converted to LTDH, while the remaining cases fall below the limit for what is considered acceptable. No area from this project ends up over 75% of the maximum score, which would indicate very good potential. To validate the indicators, Pearson's correlation coefficient was calculated. The results show that there is a negligible to a weak correlation between all indicators, except KA & STA which has a strong correlation. For an HTDH area to be relevant for conversion to LTDH, the qualitative context of the area should be suitable, and the secondary side should be able to be supplied with lower temperatures. Furthermore, there should be an opportunity for increased system capacity and finally, a conversion should be economically beneficial. The application of the indicator system is an efficient and uncomplicated approach that makes it possible to identify areas that have the potential to develop district heating in a more sustainable direction. It is also possible for stakeholders to subsequently modify the indicator system if desired. In the longer term, the indicator system is an incentive for new business opportunities, increased energy efficiency, and increased economic benefits.
76

Strategier för clicks och brick-and-clicks i en pågående pandemi : Covid-19s påverkan på clicks och brick-and-clicks strategier / Strategies for clicks and brick-and-clicks in an ongoing pandemic

Olsson, Axel, Högvik, Amanda January 2021 (has links)
I en pandemi där stora delar av världen tvingades stänga ner, tvingades även detaljhandelsföretag i Sverige tänka om och hitta nya tillvägagångsätt. Samhället uppmanades till att stanna hemma och allmänhetens köpmönster förändrades helt. Tidigare forskning visar att e-handel ökat som effekt av pandemin, däremot saknas forskning på hur e-handelns olika affärsmodeller, clicks och brick-and-clicks, påverkats av covid-19. Studien är en komparativ flerfallstudie med syfte att belysa vilka strategier clicks och brick-and-clicks tillämpat för att möta covid-19 samt om strategierna skilt sig mellan affärsmodellerna. Vidare framhåller denna studie om strategierna varit lämpade för respektive affärsmodell. Resultatet visar att clicks och brick-and-clicks använt olika strategier för att möta pandemin. Vi finner att brick-and-clicks har tillämpat strategier för kostnadsreducering och fått ökad lönsamhet som effekt. Clicks har inte utnyttjat kostnadsreduktioner i samma utsträckning utan haft en avvaktande strategi. Sekundärdata visar att clicks försäljning ökat under pandemin. Däremot visar analys av prognostiseringen att clicks underpresterar gällande lönsamhet. / In a pandemic in which large parts of the world were forced to shut down, retailcompanies in Sweden were also forced to rethink and find new ways to reachcustomers. Society was encouraged to stay at home and the public's buying patternschanged completely. Previous research shows that e-commerce has increased as aneffect of the pandemic, but there lacks research on how e-commerce's variousbusiness models, clicks and brick-and-clicks, have been affected by covid-19.In this comparative multi-case study, the purpose is to investigate which strategiesclicks and brick-and-clicks have applied to counter the covid-19 pandemic andwhether the strategies differed between the business models. Furthermore, this studyillustrates whether the strategies of each business model have been suitable. Theresults shows that clicks and brick-and-clicks used different strategies to meet thepandemic. We find that brick-and-clicks have applied cost reduction strategies andincreased profitability as a . Clicks has not used cost reductions to the same extentbut has had a more cautious strategy. The secondary data shows that clicks salesincreased during the pandemic. On the other hand, the analysis of the forecast showsthat clicks underperform in profitability.
77

The adoption of distributed ledger technology in trade and export finance operations of Swedish banks

Blidholm, Gustaf, Johnson, Mathias January 2018 (has links)
Centralized data storage and reconciliation by trusted intermediaries has historically put financial systems in the hands of a single central parties. The emergence of bitcoin and blockchain, combined with the 2008 financial crisis, has shifted the Swedish financial sector’s traditional perspectives on democratization, centralization, transparency and automation. Trade and export finance is one of many sectors investigating how blockchain and distributed ledger technology can be used other than as a digital currency system. Swedish trade and export finance connects importers, exporters, banks, credit providers, customs, and transporters into a fragmented and complex process with many stakeholders. Sweden further has a history of quickly adopting technological innovations. Banks therefore face a dynamic environment and an inconsistent, manual operative process that removes profitability incentives in providing small enterprises with credit. The adoption of DLT could provide efficiency gains and cost savings in administration, communication, reconciliation and accounting. In this thesis, the costs, benefits, and remaining barriers of implementing distributed ledger technology in Swedish trade finance are identified. Further, Swedish contextual factors’ effect on the rate of adoption is addressed. The chosen methodology of deep interviews and thorough studying of literature provides an assessment of the potential transition dynamics, forming a foundation for future investment decisions. The conclusions drawn suggest that the main costs related to adoption lie in research and development and implementation. R&D costs for distributed ledgers in the Swedish financial sector during 2019 were approximated to USD 40 million. The main benefits of automation, efficiency and reduced level of complexity were concluded to likely outweigh the costs within approximately ten to twenty years. Experience will allow companies to optimize governance structures and consensus mechanisms, while learning to expose parts of networks into public space. The innovative, adaptive Swedish market environment presumably enables faster than average diffusion of innovation, while remaining barriers in cooperation, trust, interoperability and regulation may extend the adoption process
78

Forecasting and¨Optimization Models for Integrated PV-ESS Systems: : A Case Study at KTH Live-In Lab

Flor Lopes, Mariana January 2023 (has links)
With the ever-increasing adoption of renewable energy sources, the seamless integration of PV systems into existing grids becomes imperative. Therefore, this study investigates the integration of a PV-ESS system into sustainable urban living. It entails the development and evaluation of forecasting models for PV production and electricity consumption using artificial neural network models, as well as the analysis of linear optimization algorithms. These investigations give insight into the benefits, challenges, and implications of implementing a PV-ESS system. The photovoltaic generation forecasting model demonstrates high accuracy in winter months while encountering complexity in dynamic summer conditions. The model for estimating power demand poses challenges due to a variety of factors, including human behaviour and data quality.Moreover, the study focuses on the formulation and assessment of linear optimization models with two aims: minimizing costs and optimizing self-consumption. The first continually reduces electricity costs while increasing self-consumption, whereas the second maximizes self-consumption, with limitations in winter battery use. Finally, forecast precision appears as a crucial factor for optimization models. Forecast errors have an impact on the system’s operation. Improving forecasting accuracy and adaptive control strategies are therefore critical. / Med den ständigt ökande användningen av förnybara energikällor blir sömlös integration av solcellssystem i befintliga elnät nödvändig. Därför undersöker denna studie integrationen av ett solcellsenergilagringssystem (PV-ESS) i hållbart stadsboende. Det innefattar utveckling och utvärdering av prognosmodeller för solcellsproduktion och elförbrukning med hjälp av artificiella neurala nätverksmodeller, samt analys av linjär optimeringsalgoritmer. Dessa undersökningar ger insikt om fördelarna, utmaningarna och konsekvenserna av att implementera ett PV-ESS-system. Modellen för prognostisering av solcellsgeneration visar hög noggrannhet under vintermånaderna men stöter på komplexitet under dynamiska sommarförhållanden. Modellen för att uppskatta elförbrukning står inför utmaningar på grund av olika faktorer, inklusive mänskligt beteende och datakvalitet. Dessutom fokuserar studien på formulering och utvärdering av linjära optimeringsmodeller med två mål: att minimera kostnader och optimera självkonsumtion. Den första minskar kontinuerligt elkostnader samtidigt som den ökar självkonsumtionen, medan den andra maximerar självkonsumtionen med begränsningar i vinterbatterianvändning. Slutligen framstår precision i prognoser som en avgörande faktor för optimeringsmodeller. Prognosfel påverkar systemets drift. Därför är förbättring av prognosnoggrannhet och adaptiva kontrollstrategier avgörande.
79

Fire Simulation Cost Reduction for Improved Safety and Response for Underground Spaces

Haghighat, Ali 16 October 2017 (has links)
Over the past century, great strides have been made in the advancement of mine fire knowledge since the 1909 Cherry Mine Fire Disaster, one of the worst in U.S. history. However, fire hazards remain omnipresent in underground coal mines in the U.S. and around the world. A precise fire numerical analysis (simulation) before any fire events can give a broad view of the emergency scenarios, leading to improved emergency response, and better health and safety outcomes. However, the simulation cost of precise large complex dynamical systems such as fire in underground mines makes practical and even theoretical application challenging. This work details a novel methodology to reduce fire and airflow simulation costs in order to make simulation of complex systems around fire and mine ventilation systems viable. This study will examine the development of a Reduced Order Model (ROM) to predict the flow field of an underground mine geometry using proper orthogonal decomposition (POD) to reduce the airflow simulation cost in a nonlinear model. ROM proves to be an effective tool for approximating several possible solutions near a known solution, resulting in significant time savings over calculating full solutions and suitable for ensemble calculations. In addition, a novel iterative methodology was developed based on the physics of the fluid structure, turbulent kinetic energy (TKE) of the dynamical system, and the vortex dynamics to determine the interface boundary in multiscale (3D-1D) fire simulations of underground space environments. The proposed methodology was demonstrated to be a useful technique for the determination of near and far fire fields, and could be applied across a broad range of flow simulations and mine geometries. Moreover, this research develops a methodology to analyze the tenable limits in a methane fire event in an underground coal mine for bare-faced miners, mine rescue teams, and fire brigade teams in order to improve safety and training of personnel trained to fight fires. The outcomes of this research are specific to mining although the methods outlined might have broader impacts on the other fields such as tunneling and underground spaces technology, HVAC, and fire protection engineering industries. / Ph. D.
80

Algoritmos de tratamento de curvas para determinação de parâmetros de geradores síncronos através do ensaio de resposta em frequência utilizando metodologia com inversor de frequência. / Algorithms of curves treatment for parameters determination of synchronous generators through the frequency response test using a frequency inverter.

Kornrumpf, Luiz Henrique Damato 07 December 2016 (has links)
O ensaio de resposta em frequência em geradores síncronos vem ganhando espaço nas últimas décadas, porém o alto custo dos equipamentos empregados para realização do ensaio ainda é um empecilho, tanto para fabricantes como para consumidores finais. Este trabalho tem por objetivo complementar trabalhos anteriores, através do uso de redes neurais artificiais para identificação de padrões em ensaios realizados com equipamentos de baixo custo e baixa resolução. Através das redes neurais artificiais utilizadas é possível estimar novos pontos de ensaio sem que seja necessário um novo ensaio ou até mesmo um ensaio com equipamentos mais caros. Através de uma combinação de algoritmos de tratamento de dados, é possível a aproximação de modelos ensaiados com modelos teóricos e através desses resultados obter parâmetros elétricos dos geradores síncronos. / The frequency response test on synchronous generators has been increasing in recent decades, but the high cost of equipment used for conducting the test is still a stumbling block for both manufacturers and end-consumers. This dissertation aims to complement previous work, through the use of artificial neural networks to identify patterns in tests conducted with low-cost and low-resolution equipment. Through the artificial neural networks used it is possible to estimate a new set of test points without retesting is necessary or even a more expensive assay equipments. Through a combination of data processing algorithms, the approach tested models with theoretical models is possible and through these results to obtain electrical parameters of synchronous generators.

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