• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 40
  • 35
  • 6
  • 3
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 100
  • 42
  • 28
  • 19
  • 14
  • 14
  • 13
  • 11
  • 11
  • 10
  • 9
  • 9
  • 9
  • 8
  • 8
  • 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.
41

Verification of timed automata : reachability, liveness and modelling / Vérification d'automates temporisés : sûreté, vivacité et modélisation

Tran, Thanh tung 04 November 2016 (has links)
Cette thèse revisite les algorithmes standards pour les problèmes d'accessibilité et de vivacité des automates temporisés. L'algorithme standard pour tester l'accessibilité consiste à utiliser l'inclusion de zones pour explorer efficacement un arbre de recherche abstrait. Cependant, l'ordre du parcours du graphe a une forte incidence sur l'efficacité de l'algorithme. Dans cette thèse nous introduisons deux stratégies, nommées ranking et waiting, et une combinaison des deux. De nombreux exemples montrent que la combinaison des deux stratégies aide l'algorithme d'accessibilité à éviter des explorations non nécessaires. Le problème de vivacité est couramment vérifiées par l'analyse des cycles dans l'automate temporisé. Contrairement à l'algorithme d'accessibilité, l'algorithme pour l'analyse de vivacité ne peut pas librement utiliser l'inclusion de zones. Par conséquent, il y a des situations où l'algorithme doit faire une longue exploration avant de conclure l'existence d'un cycle. Nous proposons une analyse accélérée des cycles, nommées w-iterability checking, qui permet d'améliorer la performance de l'algorithme de vivacité des automates temporisés. En plus, nous proposons une modélisation du mécanisme de démarrage du protocole FlexRay. La modélisation permet à vérifier le mécanisme dans configurations différents du réseau FlexRay. Nous présentons également un outil de visualisation qui aide à mieux comprendre le fonctionnement des algorithmes d'analyse. / This thesis revisits the standard algorithms for reachability and liveness analysis of timed automata. The standard algorithm for reachability analysis consists in using zone inclusion to efficiently explore a finite abstract zone graph of a timed automaton. It has been observed that the search order may strongly affect the performance of the algorithm. For the same algorithm, one search order may introduce a lot more exploration than another. In order to deal with the search order problem, we propose two strategies, named ranking strategy and waiting strategy, and a combination of the two. We show on a number of examples, the combining strategy helps to reduce unnecessary exploration in the standard algorithms. The standard algorithm for liveness analysis consists in looking for reachability of cycles in timed automata. But unlike the algorithm for safety analysis, the algorithm for liveness analysis cannot freely use zone inclusion. Consequently, there are situations where the algorithm has to perform a long exploration before reporting the result. In this thesis, we propose an accelerated checking for cycles in timed automata, named !-iterability checking, to improve the performance of the state-of-the-art algorithm for liveness analysis of timed automata. Furthermore, we present a new model for the startup procedure of FlexRay. The model allows to verify the procedure on different configurations of FlexRay networks. It also allows to evaluate the performance of our new strategies for safety analysis of timed automata. In addition, we present a methodology that uses visualization tools to get more insights into the execution of the algorithms.
42

Riziko výběru dodavatele s využitím fuzzy logiky / Risk Related to Selecting a Supplier Using Fuzzy Logic

Nekulová, Iveta January 2017 (has links)
This diploma thesis deals with the evaluation of security companies for ZETOR TRACTORS a.s. using fuzzy logic models. The main part of the thesis consists of proposals for the evaluation of the suppliers' evaluation of the company. Decision models are created in Microsoft Excel and Matlab. Another part of the thesis deals with analysis and comparison of results from both programs.
43

Riziko výběru dodavatele s využitím fuzzy logiky / Risk Selection of Suppliers with Fuzzy Logic

Vala, Lukáš January 2017 (has links)
The diploma thesis deals with evaluation of fertilizer suppliers using fuzzy logic models. The main part of the thesis consists of proposals for the evaluation of the company's suppliers. Decision models are created in Microsoft Excel and Matlab. Another part of the thesis deals with analysis and comparison of results from both programs.
44

Postranní kanály u Smart Card / Smart Card side channels

Pospíšil, Karel January 2011 (has links)
The thesis is dealing with smart cards and describes the known types of side channel attacks. Smart card belongs into the group of the youngest and smartest cards. In the card body, made mostly from PVC, there is a chip inserted which contains a microprocessor.Side channel attacks are trying to use the leaking information from the physical implementation of the system while processing the cryptographic algorithm. The attacker is trying to use the leaking sensitive information because under certain circumstances it can be dependent on the input data. The theoretical part is devoted to description of smart cards, their types and their safety. It describes the classification of attacks on smart cards and includes the overview of selected cryptographic algorithms used in smart cards. It also describes selected physical and logical attacks and the most frequent side channel attacks. The thesis furthermore describes possibilities of measuring the voltage-current side channel. The practical part deals with used software and hardware. This section is devoted to the measurement of power specification of smart cards and to the analysis of processed information, using the oscilloscope and workstation with AD 622 card and Simulink development environment.
45

Aplikace fuzzy logiky pro určení priority testů / The Application of Fuzzy Logic for Test Case Prioritization

Starostová, Andrea January 2014 (has links)
Diplomová práce je zaměřena na stanovení priority testovacích případů s využitím fuzzy logiky. Vhodným přístupem k získání výstupu na základě definovaného vstupu a stanovených pravidel byl zvolen fuzzy model přiřazující prioritu testovacím případům. K dosažení cíle práce byla nejprve stanovena kritéria, parametry a poté určena jejich váha pro jednotlivé testovací případy. Na závěr jsou vyhodnocena vstupní data s využitím řešení v programu MS Excel a MATLAB.
46

Aplikace fuzzy logiky při hodnocení dodavatelů firmy / The Application of Fuzzy Logic for Rating of Suppliers for the Firm

Ondra, Jan January 2015 (has links)
This diploma thesis deals with development of a fuzzy decision-making system for evaluating of REONTECH CZ s.r.o. company suppliers. The first part is dedicated to theory of fuzzy logic. The next part contains firstly an analysis of the current situation and then a description of the development process of the fuzzy decision-making system. The main outcome of this thesis is a tool that meets needs and requirements of the company and serves as a decision-making support tool.
47

Aplikace fuzzy logiky při hodnocení dodavatelů firmy / The Application of Fuzzy Logic for Rating of Suppliers for the Firm

Pafkovičová, Petra January 2016 (has links)
Master's thesis deals with design and development of two decision-making systems, which can be supportive during suppliers rating and selection the most suitable one from them. Both of the models, that one, which was made in the MS Excel, and also that one, which was made in the MATLAB, use principle of fuzzy logic and are designed according to the requirements of the selected company. Diploma thesis contains also all of theoretical bases, which are necessary for a design of both systems, and evaluation of benefits of the solution.
48

Industrialization of Lithium-Ion Prismatic Battery Cell for the Automotive Industry

Liiv, Oliver January 2020 (has links)
Energy systems in every part of the world are experiencing accelerated shifts towards more sustainable solutions which will bring far-reaching changes to our daily lives. These rapid transitions will bring impactful and vital changes to the way we fuel our cars, heat our homes and power our industries in the approaching decades. [1] The automotive sector is in high pace to electrify their cars. The number of electric passengercar sales is expected to increase by more than a factor of 60 between 2018 to 2050. Which means by that time there could be approximately 2 billion EVs on the roads and they all need batteries to run on. [1] ManyEuropean electric vehicle manufacturers have started marketing their future models globally, but automotiveli.-ion battery manufacturing capacity in Europe is merely 2.1% of the total global automotive li-ion batteryproduction. [2] Increase in sales of EV-s and energy storage systems drives the demand for li-ion batteries. This research is conducted in collaboration with Northvolt, one of the newcomers to the li-ion batterymanufacturing market in Europe. Northvolt is a Swedish-founded company in 2016, and despite its young age, Northvolt has prominent partners including BMW Group, Epiroc, Scania and the Volkswagen Group. Northvolt is with global ambition to produce the world's greenest battery cell with minimal possible carbon footprint in its Gigafactory in Sweden with 32GWh annual manufacturing capacity. Also, together with Volkswagen a 50/50 joint venture has been established to produce batteries in a 16GWh factory in Germany. After entering in different supplier agreements, Northvolt has sold a considerable amount of its first Gigafactory NV Ett production capacity to its key customers with a united equivalent of over $13billion until 2030. [3]Setting up lithium-ion battery factories for the automotive industry is a challenging task. It requires high speed and flexibility to keep up with the growing demand in a short time and still meeting all the stakeholder's requirements while keeping the highest environmental standards in place during production. To keep up with the growing demand and customer requirements a state-of.the-art industrialization project management strategy is developed. Therefore, state-of.the-art automotive project management, new product industrialization and development practices are investigated together with the best practices from the wider industry. Furthermore, Northvolt's current industrialization project management strategies are examined, and improvement proposals and tools are developed to ramp-up the current and future factories with shorter time, less cost and highest possible quality. The main aim of the thesis is to develop a project management solutions to lead industrialization of li-ionbattery Giga-factories successfully and help Northvolt fuel our cars, heat our homes, and power our industries more sustainably and innovatively. The expected outcome of the thesis is five tools developed that support the industrialization of LIB production facilities in Europe to increase the EU LIB manufacturing capacity. / Energisystem genomgår en snabb omväxling till allt mer hållbara lösningar, vilket kommer påverka våra liv markant. Dessa snabba omväxlingar kommer påverka samt främja sättet hur vi driver våra bilar, värmer våra hus och försörjer våra industrier, flera år framåt. [1] Bilsektorn som har skiftat sitt fokus till elektrifiering av sina bilar, där antalet sålda elbilar förväntas att öka sextifaldigt mellan 2018 och 2050. Detta kommer att leda till att cirka 2 miljarder elbilar kommer att åka på vägarna globalt och alla dessabilar kommer behöva framförallt litiumjonbatterier. [1] Majoriteten av biltillverkare i Europa har börjatutveckla framtida elektrifierade bilmodeller. Tillverkningen av litiumjonbatterier för elbilar i Europa utgörendast 2.1 % av den globala tillverkningen totalt. [2] En ökad försäljning av elbilar och även av produkterför energilagring, ökar efterfrågan på litiumjonbatterier. Den här undersökningen har tagits fram i samarbete med Northvolt som är en av nykomlingarna inomtillverkningen av litiumjonbatterier i Europa. Northvolt är ett svenskt bolag som startades 2016 och trotsdess tidiga fas, har de lyckats samverka med prominenta samarbetspartners som BMW group, Epiroc, Scania och Volkswagen group. Northvolts ambition är att skapa världens grönaste batteri med ett minimalt klimatavtryck. Denna produkt utvecklas i deras så kallade Gigafactory som ligger i Skellefteå och vars årliga produktion uppnår 32 Gwh. Utöver det har Northvolt i samarbete med Volkswagen fått i uppdrag att bygga upp en batterifabrik i Tyskland, vars tillverkningskapacitet kommer att uppnå till 16Gwh årligen. Efter att ha ingått i flera leverantörsavtal har Northvolt sålt en avsevärd mängd av sin produktionskapacitet för den planerade fabriken Gigafactory NV Ett till sina nyckelkunder. Detta motsvarar en investering på 13 miljarder dollar fram till 2030. [3]Att etablera en fabrik som tillverkar litiumjonbatterier för bilindustrin är en utmanande uppgift. Det kräversnabba beslut och flexibilitet för att hålla jämna steg med den växande efterfrågan på batterier av denna typ. Batterierna ska hålla måttet för de krav som kunderna har, och även ska de uppfylla alla internationella standarder för ett miljövänligt batteri.För att kunna upprätthålla den växande efterfrågan och kundkraven utvecklas nya metoder inom projektledning för att effektivisera produktionen. Det allra senaste praxis i projektledning, produktion och produkttillverkning inom bilindustrin analyseras. Dessutom beaktas senaste metoderna och praxis från andra industrier. Vidare kartläggs northvolts nuvarande strategi för deras hantering av produktionsfasen för att föreslå förbättringar och verktyg, som kan effektivisera uppbyggnaden och driften av framtida fabriker. Huvudsyftet med denna avhandling är att utveckla nya metoder inom projektledning för att kunnautveckla produktionsfasen för framtida fabriker som tillverkar litiumjonbatterier. Detta kommer leda tillatt Northvolt kommer vara en del av våra framtida liv genom att hjälpa oss att driva våra fordon, värma våra hem och driva våra fabriker på ett hållbart och effektivt sätt. Det förväntade resultatet i denna avhandling är fem utvecklade verktyg som stödjer utbyggnaden av Litiumjonbatteri fabriker i Europa föratt öka dess totala årliga produktion.
49

Mobility in rural areas: setting up operational tools to facilitate and standardize the implementation of mobility diagnoses on a regional scale / Mobilitet på landsbygden: inrättande av operativa verktyg för att underlätta och standardisera genomförandet av mobilitetsdiagnoser på regional nivå

Marchais, Alice January 2023 (has links)
While individual car use is a dominant mode of transportation in France, particularly in rural and low-density areas, it is important to promote the development of new sustainable travel paths in order to reduce dependence on cars. Planning policies and tools play a crucial role in defining such paths by providing decision-makers with a framework for data analysis, which can ensure efficient, safe, and sustainable mobility.The 2019 French mobility orientation law changed the rules of governance for mobility (i.e., management of transportation systems and mobility patterns). The territorial collectivities now have the choice of becoming mobility-organizing authorities. This law also introduced "simplified mobility plans" which aim to plan sustainable mobility on territories with less than 100,000 inhabitants. These planning documents are not mandatory but are crucial to build a policy aligned with mobility challenges, and consist of several steps, the first of which is conducting a mobility diagnosis.This thesis focuses on rural areas and on investigating the mobility diagnosis part which is a mandatory step of the simplified mobility plans, and which allows to provide a comprehensive understanding of transportation systems and mobility patterns and enable the identification of challenges and opportunities. Guided by theories on sustainable transitions and urban mobility planning, it details how to use and adapt existing tools to the specific context rural areas, that are constrained in both financial and human resources and are under-studied by current scientific research.Moreover, current methods for mobility diagnostics are too cumbersome and not always suitable for rural areas with limited resources. To address this issue, the thesis proposes a turnkey toolbox with relevant, easy-to-use indicators to standardize results and make regional - or national - planning easier.This master thesis tries in particular to answer the needs of mobility coordination by regions, in territories where local authorities have taken over mobility competences and where regions wish to support them in their planning efforts, especially in the implementation of their simplified mobility plans. A case study of Normandy will be used to understand the objectives at the regional scale when developing such simplified mobility plans.The results were obtained through a combination of qualitative methods, including document analysis as well as multicriteria analysis.The final output of the thesis is a new toolbox relying on the proposed methodology and indicators. It will simplify the process of conducting mobility diagnosis and therefore the understanding of mobility patterns in rural areas, which is key in developing plans to address their needs and to offer solutions for more sustainable and less car-dependent mobility.
50

ANALYSIS AND DESIGN OF AN INERT-CORE MACHINE FOR VEHICULAR PROPULSION

Harshini Budhi Lakshmanan (17130745) 11 October 2023 (has links)
<p dir="ltr">There is a growing demand for lower-cost, lighter-weight, and more compact electric ma-<br>chines used for vehicle propulsion. In this research, a dual-rotor inert-core machine (ICM) is<br>considered to meet this demand. In the ICM, permanent-magnet-based Halbach arrays are<br>placed on inner and outer rotating structures. This enables one to eliminate magnetic steels<br>used in the stator and rotor of traditional electric machinery. In addition, a stator structure<br>that leverages a thermal plastic is proposed that facilitates straightforward active cooling<br>of phase windings, which greatly increases current density. To support the multi-objective<br>design of the ICM, a multi-physics toolbox has been developed. Within the toolbox, electro-<br>magnetic performance is predicted using a method-of-moments-based field solver. Thermal<br>performance is assessed using a thermal equivalent circuit that includes conductive heat<br>transfer from stator windings to the surrounding environment as well as convective heat<br>transfer to moving fluids. The structural integrity of the stator is assessed using analytical<br>expressions to predict stress from material properties, geometry, and applied external forces.<br>Calculated loss of proposed designs includes those of the stator windings as well as those<br>required for active cooling. Several optimization studies have been conducted to evaluate the<br>performance of the ICM under an expected electric vehicle driving cycle. From the studies,<br>Pareto-optimal fronts are obtained and used to explore the impact of alternative cooling<br>strategies on volumetric power density.</p>

Page generated in 0.0266 seconds