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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.
121

Studie tvorby výrobní strategie / The Study of Production Strategy Formation

Voborná, Petra January 2008 (has links)
Every production unit must have a clearly determined production strategy based on the given business strategy. Today’s competitive environment is very tough and demanding and that is why each producer’s success or failure is determined by the correctly chosen productive orientation, technically advanced products and provided services, range of supply and their quality and mostly price as well. What makes firms to improve and optimize their supplies continuously is just dynamic development of the society and continuously growing consumers and users’ requirements. The keen competition on one hand makes the business more demanding, but on the other hand it brings lots of new opportunities. Looking for new ways, new procedures and management methods and especially niches in the given products and services market will bring the coveted strategy advantage. This master’s thesis deals with a change of the current production strategy in a building company, individual production aspects and improving the quality of the production process functionality itself following the objective of the firm competitiveness and business performance improvement. Within the solution I count on an ability to adapt promptly to new market requirements, I suppose that the continuing differentiation strategy will contribute to building a position of a preferential supplier of the chosen narrow market segment for large building firms in the market. Improving every production process component is the prerequisite for further development of the company.
122

Multidimensionale Bewertung von Fügetechnologien: Entwicklung einer Auswahlmethodik zur optimierten Entscheidungsfindung im Karosseriebau

Choudry, Saphir A. 30 January 2020 (has links)
Der Karosseriebau stellt einen der bedeutendsten Schritte in der Wertschöpfungskette moderner Fahrzeuge dar. Der Einsatz unterschiedlicher Werkstoffe sowie Ausführungen derzeitiger Fahrzeugkarosserien führt zu neuen Karosseriekonzepten wie dem Multi-Material-Design. Die spezifischen Eigenschaften einzelner Werkstoffe stellen jedoch insbesondere für die Fügetechnik neue Herausforderungen dar. Dementsprechend steigt die Vielfalt der zur Auswahl stehenden Fügetechnologien zum Verbinden der Werkstoffkombinationen. Die Auswahl der einzusetzenden Fügetechnologie basiert grundsätzlich auf den Erfahrungen der Produktentwicklung. Wissenschaftliche Ansätze beschränken sich im Rahmen des Auswahlprozesses von Fügetechnologien oftmals auf die ökonomische Bewertung für einzelne Fügepunkte. Ein integrierter Bewertungsansatz, welcher bereits während der Festlegung von Werkstoff und Konstruktion die Aspekte der Fügetechnik hinsichtlich ökonomischer, ökologischer sowie technologischer Faktoren für eine gesamte Baugruppe umfasst, existiert bisher nicht. Aufgrund der Intransparenz hinsichtlich monetärer und nicht-monetärer Eigenschaften der jeweiligen Fügetechnologie sowie der zunehmenden Entscheidungskomplexität leitet sich der Bedarf nach einer methodischen Unterstützung des Auswahlprozesses ab. Ziel der Forschung ist es, durch die Entwicklung einer multidimensionalen Auswahlmethodik eine optimierte Entscheidungsfindung in der Karosserieentwicklung zu ermöglichen. / The car body shop has become one of the most significant steps in the automobile value chain nowadays. The usage of a variety of different materials and configurations of current vehicle bodies in lightweight construction leads to new body concepts such as the multi-material design. However, the specific properties of individual materials lead to new challenges, especially in the joining technology where existing technologies face numerous restrictions. Therefore, new joining processes are required, which also results in an increased diversity of joining technologies and complexity of the decision-making. To date, the selection of a joining technology for a component is mostly based on the experience of the product development. The selection process of extant scientific approaches, however, is often limited to the economic assessment of joining technologies for individual joints. An integrated assessment approach, which already includes the aspects of joining technologies with regards to economic, ecological and technological factors for an entire assembly during the definition of material and design, does not exist. Due to the non-transparency of the overall monetary and non-monetary impact of the respective joining technology, the need for a methodological support for the selection process is derived. An essential part of this research work is the development of a multidimensional selection methodology to allow an optimized decision-making in the early stage of car body development.
123

Advanced Control Strategies for Diesel Engine Thermal Management and Class 8 Truck Platooning

John Foster (9179864) 29 July 2020 (has links)
<div> <div> <div> <p>Commercial vehicles in the United States account for a significant fraction of greenhouse gas emissions and NOx emissions. The objectives of this work are reduction in commercial vehicle NOx emissions through enhanced aftertreatment thermal management via diesel engine variable valve actuation and the reduction of commercial vehicle fuel consumption/GHG emissions by enabling more effective class 8 truck platooning. </p> <p><br></p><p>First, a novel diesel engine aftertreatment thermal management strategy is proposed which utilizes a 2-stroke breathing variable value actuation strategy to increase the mass flow rate of exhaust gas. Experiments showed that when allowed to operate with modestly higher engine-out emissions, temperatures comparable to baseline could be achieved with a 1.75x exhaust mass flow rate, which could be beneficial for heating the SCR catalyst in a cold-start scenario. </p> <p><br></p><p>Second, a methodology is presented for characterizing aerodynamic drag coefficients of platooning trucks using experimental track-test data, which allowed for the development of high-fidelity platoon simulations and thereby enabled rapid development of advanced platoon controllers. Single truck and platoon drag coefficients were calculated for late model year Peterbilt 579’s based on experimental data collected during J1321 fuel economy tests for a two-truck platoon at 65 mph with a 55’ truck gap. Results show drag coefficients of 0.53, 0.50, and 0.45 for a single truck, a platoon front truck, and a platoon rear truck, respectively. </p> <p><br></p><p>Finally, a PID-based platoon controller is presented for maximizing fuel savings and gap control on hilly terrain using a dynamically-variable platoon gap. The controller was vetted in simulation and demonstrated on a vehicle in closed-course functionality testing. Simulations show that the controller is capable of 6-9% rear truck fuel savings on a heavily-graded route compared to a production-intent platoon controller, while increasing control over the truck gap to discourage other vehicles from cutting in. </p></div></div></div>
124

Design of a 2-D Lattice Flower Constellation for Earth observation applying the twin satellite concept

Martín-Fuertes Brañas, Julia January 2023 (has links)
Events such as forest fires or floods are a danger to our Earth’s environment and the people living in it. The sooner they can be detected, the less damage they can cause. An idea arises: use satellites to monitor the Earth and relay information to prevention and rescue organizations in a very short time, regardless of accessibility from ground. PandionAI is a Swedish start-up that aims to create a constellation of satellites that will carry built-in machine learning models that analyze the Earth images and detect early on such environmental catastrophes. The aim of this thesis is to design a constellation for such purpose. In parallel, a target list that includes potential places of interest for such events will be developed and the constellation performance will be evaluated with it by defining Key Performance Indicators (KPIs). The target list has a dynamic nature as weather changes and climate evolves, so events of interest will be at different places in the globe as time passes. Because of this, four different target lists were developed, one per season. The events covered by the target lists are the environmental hazards: fires, floods, deforestation and CO2 footprint from factories. Constellation design is a highly complex problem due to its infinite possible solutions for a given purpose. Nevertheless, one can optimize for specific design parameters and assumptions. This thesis proposes a model in which for a given number of total satellites, multiple constellations are compared, and the search for the optimal design is performed given the defined KPIs. Constellations in the optimization process are designed applying the 2-D Lattice Flower Constellation method and adding the twin satellite concept. / Händelser som skogsbränder eller översvämningar är en fara för vår jords miljö och människorna som lever i den. Ju tidigare de kan upptäckas, desto mindre skada kan de orsaka. En idé uppstår: att använda satelliter för att övervaka jorden och vidarebefordra information till förebyggande och räddningsorganisationer på mycket kort tid, oavsett tillgänglighet från marken. PandionAI är en svensk start-up som vars mål är att skapa en konstellation av satelliter som ska bära inbyggda maskininlärningsmodeller som analyserar analyserar satelliters bilder bilder och tidigt upptäcker sådana miljökatastrofer. Syftet med denna uppsats är att utforma en konstellation för detta ändamål. Parallellt kommer en mållista som inkluderar potentiella platser av intresse för sådana händelser att utvecklas och konstellationens prestanda kommer att utvärderas med den genom att definiera Key Performance Indicator-parametrar (KPI). Mållistan har en dynamisk karaktär, eftersom väder och klimat varierar över året säsonger och händelser, så händelser av intresse kommer att finnas på olika platser i världen med tiden. På grund av detta utvecklades fyra olika mållistor, en per säsong. De händelser som omfattas av mållistorna är miljöriskerna: bränder, översvämningar, avskogning och CO2 fotavtryck från fabriker. Konstellationsdesign är ett mycket komplext problem på grund av dess oändliga många möjliga lösningar för ett givet syfte. Ändå kan man optimera för specifika designparametrar och antaganden. Denna studie syftar till att förslå en modell för ett totalt givet antal satelliter, där flera konstellationer jämförs och finna den optimala designen givet KPIerna. Konstellationer i optimeringsprocessen är designade med tillämpning av 2D Lattice Flower Constellation-metoden och användning av tvilling-satellit-konceptet till tvillingsatellitkonceptet.
125

Contributions à la co-optimisation contrôle-dimensionnement sur cycle de vie sous contrainte réseau des houlogénérateurs directs / Contribution to the sizing-control co-optimization over life cycle under grid constraint for direct-drive wave energy converters

Kovaltchouk, Thibaut 09 July 2015 (has links)
Les Energies Marines Renouvelables (EMR) se développent aujourd’hui très vite tant au niveau de la recherche amont que de la R&D, et même des premiers démonstrateurs à la mer. Parmi ces EMR, l'énergie des vagues présente un potentiel particulièrement intéressant. Avec une ressource annuelle brute moyenne estimée à 40 kW/m au large de la côte atlantique, le littoral français est plutôt bien exposé. Mais l’exploitation à grande échelle de cette énergie renouvelable ne sera réalisable et pertinente qu'à condition d'une bonne intégration au réseau électrique (qualité) ainsi que d'une gestion et d'un dimensionnement optimisé au sens du coût sur cycle de vie. Une première solution de génération tout électrique pour un houlogénérateur a d’abord été évaluée dans le cadre de la thèse de Marie RUELLAN menée sur le site de Bretagne du laboratoire SATIE (ENS de Cachan). Ces travaux ont mis en évidence le potentiel de viabilité économique de cette chaîne de conversion et ont permis de poser la question du dimensionnement de l’ensemble convertisseur-machine et de soulever les problèmes associés à la qualité de l’énergie produite. Puis une seconde thèse a été menée par Judicaël AUBRY dans la même équipe de recherche. Elle a consisté, entre autres, en l’étude d’une première solution de traitement des fluctuations de la puissance basée sur un système de stockage par supercondensateurs. Une méthodologie de dimensionnement de l’ensemble convertisseur-machine et de gestion de l’énergie stockée fut également élaborée, mais en découplant le dimensionnement et la gestion de la production d’énergie et de ceux de son système de stockage. Le doctorant devra donc : 1. S’approprier les travaux antérieurs réalisés dans le domaine de la récupération de l’énergie des vagues ainsi que les modèles hydrodynamiques et mécaniques réalisés par notre partenaire : le LHEEA de l’Ecole Centrale de Nantes - 2. Résoudre le problème du couplage entre dimensionnement/gestion de la chaîne de conversion et dimensionnement/gestion du système de stockage. 3. Participer à la réalisation d’un banc test à échelle réduite de la chaine électrique et valider expérimentalement les modèles énergétiques du stockage et des convertisseurs statiques associés - 4. Proposer une méthodologie de dimensionnement de la chaine électrique intégrant le stockage et les lois de contrôle préalablement élaborées 5. Déterminer les gains en termes de capacités de stockage obtenus grâce à la mutualisation de la production (parc de machines) et évaluer l’intérêt d’un stockage centralisé - 6. Analyser l’impact sur le réseau d’une production houlogénérée selon divers scenarii, modèles et outils développés par tous les partenaires dans le cadre du projet QUALIPHE. L’exemple traité sera celui de l’Ile d’Yeu (en collaboration avec le SyDEV. / The work of this PhD thesis deals with the minimization of the per-kWh cost of direct-drive wave energy converter, crucial to the economic feasibility of this technology. Despite the simplicity of such a chain (that should provide a better reliability compared to indirect chain), the conversion principle uses an oscillating system (a heaving buoy for example) that induces significant power fluctuations on the production. Without precautions, such fluctuations can lead to: a low global efficiency, an accelerated aging of the fragile electrical components and a failure to respect power quality constraints. To solve these issues, we firstly study the optimization of the direct drive wave energy converter control in order to increase the global energy efficiency (from wave to grid), considering conversion losses and the limit s from the sizing of an electrical chain (maximum force and power). The results point out the effect of the prediction horizon or the mechanical energy into the objective function. Production profiles allow the study of the flicker constraint (due to grid voltage fluctuations) linked notably to the grid characteristics at the connection point. Other models have also been developed to quantify the aging of the most fragile and highly stressed components, namely the energy storage system used for power smoothing (with super capacitors or electrochemical batteries Li-ion) and power semiconductors.Finally, these aging models are used to optimize key design parameters using life-cycle analysis. Moreover, the sizing of the storage system is co-optimized with the smoothing management.
126

Beyond hairballs: depicting complexity of a kinase-phosphatase network in the budding yeast

Abd-Rabbo, Diala 01 1900 (has links)
No description available.
127

Ověření funkce bezkontaktního snímače hladiny paliva v palivové nádrži / Testing and calibration of fuel level gauge

HAIKL, Petr January 2013 (has links)
This work inkluse measurement principles for measuring liquid level in tanks with a focus on fuel. Are described most frequently used types of liquid level sensors, focusing on fuel. The work inkluse design chosen technical solutions fuel level sensor and its technical implementation, including the technical implementation and verification of its functionality and calibration.
128

Low-Power Policies Based on DVFS for the MUSEIC v2 System-on-Chip

Mallangi, Siva Sai Reddy January 2017 (has links)
Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode. / Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.

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