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PORUŠOVÁNÍ SLOŽENÝCH TĚLES VYVOLANÉ MATERIÁLOVOU NESPOJITOSTÍ / DAMAGE OF COMPOUND STRUCTURES CAUSED BY MATERIAL DISCONTINUITYKorbel, Jakub January 2012 (has links)
This Ph.D. thesis deals with modeling of compound structures containing defects such as cracks or notches. Attention was mainly focused on structures manufactured out of metals and polymers. Presented results were obtained from experimental measurements, which were compared with theoretical estimations of the ultimate states of the compound structures. Theoretical estimations were obtained by the application of the generalized fracture mechanics, whose integral part is based on numerical solution provided by finite element method. The results of the Ph.D. thesis contribute both to prediction of the limit states of compound objects, and to verification of the validity of the generalized fracture mechanics.
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Popis porušování vrstevnatých polymerních prostředí / Description of Failure of the Multilayer Polymer StructureZouhar, Michal January 2014 (has links)
The aim of this thesis is to describe behavior of cracks in layered polymer materials. Quasi-brittle fracture (through the initiation and subsequent crack propagation mechanism) under low stresses is the most common mode of failure of polymer materials. In this case plastic deformations are localized in the vinicity of the crack tip and linear elastic fracture mechanics description of the crack behavior can be used. The knowledge of fracture parameters change during the crack propagation in multilayer body is a key point for establishing of the maximum load and consequently for the assessment of the residua lifetime. In contrast to homogeneous bodies the estimation of stress intensity factors for multilayer (composite) structure is numerically more elaborated and the fracture mechanics approach is complicated by the existence of interfaces between single layers, where material parameters are changed by a step. Special attention is paid to the configuration of a crack growing close to the material interface and along the interface. For the crack with tip on the material interface the effective values of stress intensity factor based on the crack stability criteria are estimated. It is shown that under special conditions (depending mainly on the elastic mismatch of materials) the existence of material interface has positive influence on the lifetime of the multilayered structure.
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Evaluation of KPI Monitoring Tools for an Automotive SupplierMirza, Hasnain Haider Baig 24 August 2016 (has links)
Automotive SPICE is used to evaluate the efficiency of the development processes for OEMs and ECU suppliers. It is a domain specific version of SPICE. Many automotive manufacturers are demanding Automotive SPICE level 2 from their suppliers. Application life cycle management solutions specific to automotive industry focus more on standardisation yet providing very little information about performance of processes. This thesis shows how Business Intelligence (BI) solutions can be helpful in achieving Automotive SPICE level 2 compliance and as comprehensive reporting tools. Moreover the evaluation of approaches for implementation of different BI systems has shown that commercial solutions can be beneficial for small to medium size suppliers. Implementing a BI solution can also point out possible improvement opportunities and bad practices for an organisation. The implemented BI system can only be efficient and useful if the underlying data is accurate and responsive.
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A Deep Learning Approach To Vehicle Fault Detection Based On Vehicle BehaviorKhaliqi, Rafi, Iulian, Cozma January 2023 (has links)
Vehicles and machinery play a crucial role in our daily lives, contributing to our transportationneeds and supporting various industries. As society strives for sustainability, the advancementof technology and efficient resource allocation become paramount. However, vehicle faultscontinue to pose a significant challenge, leading to accidents and unfortunate consequences.In this thesis, we aim to address this issue by exploring the effectiveness of an ensemble ofdeep learning models for supervised classification. Specifically, we propose to evaluate the performance of 1D-CNN-Bi-LSTM and 1D-CNN-Bi-GRU models. The Bi-LSTM and Bi-GRUmodels incorporate a multi-head attention mechanism to capture intricate patterns in the data.The methodology involves initial feature extraction using 1D-CNN, followed by learning thetemporal dependencies in the time series data using Bi-LSTM and Bi-GRU. These models aretrained and evaluated on a labeled dataset, yielding promising results. The successful completion of this thesis has met the objectives and scope of the research, and it also paves the way forfuture investigations and further research in this domain.
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Periodic and Non-Periodic Filter Structures in Lasers / Periodiska och icke-periodisk filterstrukturer i lasrarEnge, Leo January 2020 (has links)
Communication using fiber optics is an integral part of modern societies and one of the most important parts of this is the grating filter of a laser. In this report we introduce both the periodic and the non-periodic grating filter and discuss how there can be resonance in these structures. We then provide an exact method for calculating the spectrum of these grating filters and study three different methods to calculate this approximately. The first one is the \emph{Fourier approximation} which is very simple. For the studied filters the fundamental form of the results for this method is correct, even though the details are not. The second method consists of calculating the spectrum exactly for some values and then use interpolation by splines. This method gives satisfactory results for the types of gratings analysed. Finally a method of perturbation is provided for the periodic grating filter as well as an outline for how this can be extended to the non-periodic grating filter. For the studied filters the results of this method are very promising. The method of perturbations may also give a deeper understanding of how a filter works and we therefore conclude that it would be of interest to study the method of perturbations further, while all the studied methods can be useful for computation of the spectrum depending on the required precision. / Fiberoptisk kommunikation utgör en viktig del i moderna samhällen och en av de grudläggande delarna av detta är Bragg-filter i lasrar. I den här rapporten introducerar vi både det periodiska och det icke-periodiska Bragg-filtret och diskuterar hur resonans kan uppstå i dessa. Vi presenterar sedan en exakt metod för att beräkna spektrumet av dessa filter samt studerar tre approximativa metoder för att beräkna spektrumet. Den första metoden är \emph{Fourier-approximationen} som är väldigt enkel. För de studerade filtrena blir de grundläggande formerna korrekta med Fourier-approximationen, medan detaljerna är fel. Den andra metoden består av att räkna ut spektrumet exakt för några punkter och sedan interpolera med hjälp av splines. Den här metoden ger mycket bra resultat för de studerade filtrena. Till sist presenteras en metod baserad på störningsteori för det periodiska filtret, samt en översikt över hur det här kan utökas till det icke-periodiska filtret. Denna metod ger mycket lovande resulat och den kan även ge djupare insikt i hur ett filter fungerar. Vi sluter oss därför till att det vore intressant att vidare studera metoder med störningar, men även att alla studerade metoder kan vara användabara för beräkningen av spektra beroende på vilken precision som krävs.
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Реинжиниринг системы управленческий показателей производственного предприятия и разработка аналитической отчетности на платформе Microsoft Power BI : магистерская диссертация / Reengineering of the system of management indicators of a manufacturing enterprise and development of analytical reporting on the Microsoft Power BI platformКолоколов, А. С., Kolokolov, A. S. January 2022 (has links)
Актуальность выбранной темы обусловлена потребностью предприятия ООО «ПРОФХОЛОД», которое выбрало путь цифровой трансформации бизнеса. Цель трансформации – опираться на данные при разработке и принятии управленческих решений, при этом не тратить значительные ресурсы на расчет показателей. Компания ОOO «ПРОФХОЛОД» разрабатывает системы и технологии управления теплом. Является лидером Российского рынка в сфере по объему продаж сэндвич-панелей с пенополиуретаном и полиизоциануратом. Цель работы: повышение качества управленческой отчетности компании путем разработки и внедрения в компанию ООО «Профхолод» BI-аналитики на базе инструмента Microsoft Power BI. Объектом исследования является бизнес-процесс в бизнес-аналитике. Предметом исследования следует указать внедрение и разработку бизнес-аналитики в бизнес-процессы через автоматизацию отчетности компании на базе инструментов Micrasoft Power BI. Результаты работы заключается в том, что были определены понятия Бизнес-аналитики и ее основные инструменты. С практической точки зрения были автоматизированы системы отчетности в компании и тем самым бизнес-процессы на предприятие были модернизированы через внедрение BI. Научная новизна состоит в том, что проанализированы различные системы BI и подробно изучены современные функции Power BI для реализации проекта. Экономическая эффективность имеет лишь прогнозный характер и показывает по подсчетам, что система полностью окупит себя. / The relevance of the chosen topic is due to the needs of the enterprise PROFHOLOD LLC, which has chosen the path of digital business transformation. The goal of the transformation is to rely on data in the development and adoption of management decisions, while not spending significant resources on calculating indicators. LLC "PROFHOLOD" develops systems and technologies for heat management. It is the leader of the Russian market in terms of sales of sandwich panels with polyurethane foam and polyisocyanurate. The purpose of the work: improving the quality of the company's management reporting by developing and implementing BI-analytics based on the Microsoft Power BI tool in Profholod LLC. The object of study is a business process in business analytics. The subject of the study should be the implementation and development of business intelligence in business processes through the automation of company reporting based on Micrasoft Power BI tools. The results of the work lies in the fact that the concepts of Business Intelligence and its main tools were defined. From a practical point of view, the reporting systems in the company were automated and thus the business processes in the enterprise were modernized through the introduction of BI. The scientific novelty lies in the fact that various BI systems have been analyzed and modern Power BI functions for project implementation have been studied in detail. Economic efficiency is only predictive in nature and shows, according to estimates, that the system will fully pay for itself.
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Finfördelad Sentimentanalys : Utvärdering av neurala nätverksmodeller och förbehandlingsmetoder med Word2Vec / Fine-grained Sentiment Analysis : Evaluation of Neural Network Models and Preprocessing Methods with Word2VecPhanuwat, Phutiwat January 2024 (has links)
Sentimentanalys är en teknik som syftar till att automatiskt identifiera den känslomässiga tonen i text. Vanligtvis klassificeras texten som positiv, neutral eller negativ. Nackdelen med denna indelning är att nyanser går förlorade när texten endast klassificeras i tre kategorier. En vidareutveckling av denna klassificering är att inkludera ytterligare två kategorier: mycket positiv och mycket negativ. Utmaningen med denna femklassificering är att det blir svårare att uppnå hög träffsäkerhet på grund av det ökade antalet kategorier. Detta har lett till behovet av att utforska olika metoder för att lösa problemet. Syftet med studien är därför att utvärdera olika klassificerare, såsom MLP, CNN och Bi-GRU i kombination med word2vec för att klassificera sentiment i text i fem kategorier. Studien syftar också till att utforska vilken förbehandling som ger högre träffsäkerhet för word2vec. Utvecklingen av modellerna gjordes med hjälp av SST-datasetet, som är en känd dataset inom finfördelad sentimentanalys. För att avgöra vilken förbehandling som ger högre träffsäkerhet för word2vec, förbehandlades datasetet på fyra olika sätt. Dessa innefattar enkel förbehandling (EF), samt kombinationer av vanliga förbehandlingar som att ta bort stoppord (EF+Utan Stoppord) och lemmatisering (EF+Lemmatisering), samt en kombination av båda (EF+Utan Stoppord/Lemmatisering). Dropout användes för att hjälpa modellerna att generalisera bättre, och träningen reglerades med early stopp-teknik. För att utvärdera vilken klassificerare som ger högre träffsäkerhet, användes förbehandlingsmetoden som hade högst träffsäkerhet som identifierades, och de optimala hyperparametrarna utforskades. Måtten som användes i studien för att utvärdera träffsäkerheten är noggrannhet och F1-score. Resultaten från studien visade att EF-metoden presterade bäst i jämförelse med de andra förbehandlingsmetoderna som utforskades. Den modell som hade högst noggrannhet och F1-score i studien var Bi-GRU. / Sentiment analysis is a technique aimed at automatically identifying the emotional tone in text. Typically, text is classified as positive, neutral, or negative. The downside of this classification is that nuances are lost when text is categorized into only three categories. An advancement of this classification is to include two additional categories: very positive and very negative. The challenge with this five-class classification is that achieving high performance becomes more difficult due to the increased number of categories. This has led to the need to explore different methods to solve the problem. Therefore, the purpose of the study is to evaluate various classifiers, such as MLP, CNN, and Bi-GRU in combination with word2vec, to classify sentiment in text into five categories. The study also aims to explore which preprocessing method yields higher performance for word2vec. The development of the models was done using the SST dataset, which is a well-known dataset in fine-grained sentiment analysis. To determine which preprocessing method yields higher performance for word2vec, the dataset was preprocessed in four different ways. These include simple preprocessing (EF), as well as combinations of common preprocessing techniques such as removing stop words (EF+Without Stopwords) and lemmatization (EF+Lemmatization), as well as a combination of both (EF+Without Stopwords/Lemmatization). Dropout was used to help the models generalize better, and training was regulated with early stopping technique. To evaluate which classifier yields higher performance, the preprocessing method with the highest performance was used, and the optimal hyperparameters were explored. The metrics used in the study to evaluate performance are accuracy and F1-score. The results of the study showed that the EF method performed best compared to the other preprocessing methods explored. The model with the highest accuracy and F1-score in the study was Bi-GRU.
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Smarta beslut i små och medelstora företag : Kritiska faktorer för en lyckad implementering av Business IntelligenceFerlander, Ludvig, Kullander, Kristoffer January 2024 (has links)
Denna studie undersöker vad BI-konsulter ser som de kritiska faktorer som påverkar implementeringen av Business Intelligence (BI) i små och medelstora företag (SME) i Sverige. Trots de betydande fördelarna med BI, såsom förbättrad operativ effektivitet och datadrivet beslutsfattande, möter SME:s ofta utmaningar vid implementeringen. Studien syftar till att identifiera och analysera dessa faktorer med hjälp av Technology-Organization-Environment (TOE) ramverket. För att uppnå syftet genomfördes semistrukturerade intervjuer med BI-konsulter som har omfattande erfarenhet av att arbeta med SME:s. Resultaten visade att förståelse och kompetens relaterat till BI är kritiska för en lyckad implementering vilket korrelerar med faktorer som ledningsstöd, komplexitet, resursallokering och kompatibilitet. Denna uppsats bidrar till en djupare förståelse för de faktorer som påverkar BI-implementering i svenska SME:s och ger insikter som kan hjälpa företag att framgångsrikt utnyttja BI-teknikerför att förbättra sin operativa effektivitet och konkurrenskraft.
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Regulation der Expression von Scavenger Receptor BI (SR-BI) und des bidirektionalen Cholesterolflux durch den Cholesterol- und Vitamin-E-Gehalt in HepG2-Zellen und High Density LipoproteinenBarikbin, Payman 20 October 2004 (has links)
Der Scavenger Receptor BI (SR-BI) vermittelt den selective lipid transfer von Cholesterol und Vitamin E aus HDL in die Leber. Die zelluläre Aufnahme verschiedener Lipide aus HDL über den selben Mechanismus, vermittelt durch den selben Rezeptor wirft die Frage auf, ob diese Aufnahmeprozesse einander beeinflussen. Aktuelle Forschungsergebnisse zeigen, daß die Aufnahme von neutralen Lipiden (Cholesterolester, Triacylglycerol) aus HDL in die Zelle von der Lipidzusammensetzung der Donorpartikel abhängen könnte. Wir untersuchten, ob der Vitamin-E-Gehalt von HDL die Aufnahme und den Efflux von Cholesterol in und aus HepG2-Zellen beeinflußt. Die Inkubation von HepG2-Zellen mit [3H]Cholesterol-markiertem HDL mit ansteigendem Vitamin-E-Gehalt ergab eine steigende Aufnahme von Vitamin E, während sich die Cholesterolaufnahme nicht veränderte. Der erhöhte zelluläre Gehalt an Vitamin E bewirkte eine Reduktion der PKC-Alpha- und SR-BI-Expression in Verbindung mit einem erniedrigten Cholesterolefflux aus HepG2-Zellen zu nativem HDL als Akzeptorpartikel. Die Verarmung der Zellen an Cholesterol führte zu einer erniedrigten PKC-Alpha- und SR-BI-Expression. Hingegen veränderte die Erhöhung des zellulären Cholesterolgehalts von HepG2-Zellen die PKC-Alpha- und SR-BI-Expression nicht, während der Cholesterolefflux aus HepG2-Zellen zu HDL im Vergleich zur Kontrolle gesteigert war. Wir schließen aus diesen Ergebnissen, daß Vitamin E und Cholesterol die SR-BI-Expression modulieren können und daß SR-BI den Efflux und möglicherweise auch den Influx von Cholesterol in HepG2-Zellen vermittelt. / The scavenger receptor BI (SR-BI) mediates selective lipid transfer of cholesterol and vitamin E from HDL to the liver. Cellular uptake of different lipids from HDL by the same mechanism, mediated by the same receptor rise the question, whether these uptake processes affect each other. Recent results show that the cellular uptake of neutral lipids (cholesterol ester, triacylglycerol) from HDL may depend on the lipid composition of the donor particles. We investigated whether the vitamin E-content of HDL affects cholesterol uptake and efflux by HepG2 cells. Incubation of HepG2 cells with [3H]cholesterol-labeled HDL, which contained increasing vitamin E-concentrations resulted in an increased uptake of vitamin E, whereas the cholesterol uptake did not change. The increased cellular content of vitamin E caused a decreased PKCalpha and SR-BI-expression combined with a decreased cholesterol-efflux from HepG2 cells to native HDL as acceptor. Depletion of cellular cholesterol decreased PKC-alpha and SR-BI-expression in HepG2 cells. Increase of cellular cholesterol of HepG2 cells, however, did not change PKCalpha and SR-BI-expression, whereas cholesterol-efflux from HepG2 cells to HDL increased. We conclude that vitamin E and cholesterol can modulate the SR-BI-expression and that SR-BI mediates the efflux and possibly also the influx of cholesterol by HepG2 cells.
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Nature and organization of the CuO 2 -plane / as experimentally probed in the prototype high-temperature superconductor Bi2201Dudy, Lenart E. 03 April 2009 (has links)
Diese experimentelle Arbeit beschäftigt sich mit Einkristallen der Bi Kuprate. Mittels Rastertunnelmikroskopie und der Beugung langsamer Elektronen wurde die strukturellen Eigenschaften untersucht. Es wurde ein bestehendes pseudobinäres Blei-Temperatur Phasendiagram erweitert. Mittels der Charakterisierungsresultate der energiedispersive Röntgenspektroskopie und der AC-Suszeptibilität wurde gezeigt, dass an bestimmten Lochdotierungen die Sprungtemperatur unterdrückt ist. Diese Tatsache wird für zwei Variationen des Bi2201 Kuprat-Systems bewiesen - durch Literaturdaten auch für LSCO. Desweiteren wurde argumentiert, dass die sogenannte Checkerboard-Ordnung nicht eine Ordnung der elektronischen Struktur ist. Vielmehr kann davon ausgegangen werden, dass Sie durch Dotanten-Atome verursacht wird. Dabei könnte der zusätzlichen Sauerstoff eine Bedeutung haben. Die Pseudolücken-Phase wurde mittels winkelaufgelöster Photoemission (ARPES) sowie Widerstandsmessungen untersucht. Durch ARPES konnte gezeigt werden, dass die Lücke in der antinodalen Richtung keinen grossen Anteil einer Supraleitungslücke aufweist, sondern mehr von der Pseudolückenphase bestimmt ist. Es wurde festgestellt, dass in der winkelaufgelösten Photoemission nur eine Übergangstemperatur sichtbar war, während bei den Widerstandsmessungen zwei Übergangstemperaturen sichtbar waren. Zudem wurde gezeigt, dass die Pseudolückenphase auch auf der überdotierten Seite existiert. Ein ganz und gar neues Ergebnis ist der dotierungsabhängige Verlauf der Pseudolücken-Temperatur und der in ARPES gemessenen Pseudolücke. Es zeigte sich dort zweifelsfrei, dass die Pseudolücken-Eigenschaften an genau denselben Dotierungen starke Änderungen aufweisen, an denen auch die Sprungtemperatur unterdrückt ist. Deshalb wurde propagiert, dass die Supraleitung durch Paarung von Defektlöchern in einem ansonsten magnetisch- und ladungs-hochgeordnetem Elektronensystem entsteht. / This thesis deals with the experimental exploration of the high-temperature superconducting Bi-cuprate system and mainly with single crystals of the one-layer Bi2201. To begin, the structural change resulting from Pb substitution was explored by using topological scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). The resulting morphologies were explained in a pseudo-binary phase-diagram. Using energy dispersive x-ray analysis and AC-susceptibility, it was proven that, for two variations of Bi2201 and also for LSCO, the superconducting transition temperature (TC) always drops at the same hole-doping values - an effect that might be explained by the so-called ''magic doping fractions''. By analyzing STM-data, it was reasonably argued that the so-called ''checkerboard order'' is not preferentially due to an ordering of the carriers in the Copper-Oxygen-plane. In the interpretation presented here, it is caused by dopant-atoms or dopant-complexes. The role of the Oxygen might be of particular importance. Measurements concerning the pseudogap-phase were then shown. Using angular resolved photoemission (ARPES), it was found that the gap in the antinodal direction is dominantly caused by the pseudogap-phase. Interestingly, while resistivity measurements detect two crossover temperatures, ARPES detects only the lower pseudogap-temperature. It can also be stated that the pseudogap also exists in the overdoped region. The most important finding about the pseudogap-temperature and the pseudogap-magnitude was that they also react on the doping values of the depressions in TC. Due to this finding, it was proposed that superconductivity occurs when an otherwise perfect charge-ordered and spin-ordered two-dimensional electronic system has mobile defective holes.
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