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Robust analysis of uncertain descriptor systems using non quadratic Lyapunov functions / Analyse robuste des systèmes descripteurs incertains par des fonctions de Lyapunov non quadratiquesDos Santos Paulino, Ana Carolina 12 December 2018 (has links)
Les systèmes descripteurs incertains sont convenables pour la représentation des incertitudes d’un modèle, du comportement impulsif et des contraintes algébriques entre les variables d’état. Ils peuvent décrire bien plus de phénomènes qu’un système dynamique standard, mais, en conséquence, l’analyse des systèmes descripteurs incertains est aussi plus complexe. Des recherches sont menées de façon à réduire le degré de conservatisme dans l’analyse des systèmes descripteurs incertains. L’utilisation des fonctions de Lyapunov qui sont en mesure de générer des conditions nécessaires et suffisantes pour une telle évaluation y figurent. Les fonctions de Lyapunov polynomiales homogènes font partie de ces classes, mais elles n’ont jamais été employées pour les systèmes descripteurs incertains. Dans cette thèse, nous comblons ce vide dans la littérature en étendant l’usage des fonctions de Lyapunov polynomiales homogènes du cas incertain standard vers les systèmes descripteurs incertains. / Uncertain descriptor systems are a convenient framework for simultaneously representing uncertainties in a model, as well as impulsive behavior and algebraic constraints. This is far beyond what can be depicted by standard dynamic systems, but it also means that the analysis of uncertain descriptor systems is more complex than the standard case. Research has been conducted to reduce the degree of conservatism in the analysis of uncertain descriptor systems. This can be achieved by using classes of Lyapunov functions that are known to be able to provide necessary and sufficient conditions for this evaluation. Homogeneous polynomial Lyapunov functions constitute one of such classes, but they have never been employed in the context of uncertain descriptor systems. In this thesis, we fill in this scientific gap, extending the use of homogeneous polynomial Lyapunov functions from the standard uncertain case for the uncertain descriptor one.
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Méthodes géométriques et numériques en contrôle optimal et applications au transfert orbital à poussée faible et à la nage à faible nombre de Reynolds / Geometric and numerical methods in optimal control and applications to the swimming problem at low Reynolds number and to low thrust orbital transferRouot, Jérémy 21 November 2016 (has links)
Dans la première partie, on propose une étude sur le problème de nage à faible nombre de Reynolds à partir d'unnageur modélisant la nage des copépodes et du nageur historique de Purcell.En minimisant l’énergie dissipée par les forces de trainée sur le fluide, laquelle est reliée au concept d’efficacitéd’une nage, on utilise les outils géométriques et numériques du contrôle optimal. Le principe du maximum estutilisé pour calculer les contrôles optimaux périodiques satisfaisant une condition de transversalité fine reliée à laminimisation de l’énergie mécanique pour un déplacement fixé où à la maximisation de l’efficacité. Ce sont desproblèmes sous-Riemanniens ce qui permet d’utiliser des techniques efficaces telles que l’approximation nilpotentepour calculer des nages de faible amplitude et qui est utilisée pour calculer des nages sur le vrai système parcontinuation. Les conditions nécessaires et suffisantes du second ordre sont calculées pour sélectionner desminimiseurs faible dans le cas d’une famille de nages périodiques.Dans la seconde partie, on s‘intéresse à la trajectoire d’un engin spatial contrôlé sous l’action d’un champ à forcecentral et où l’on considère les perturbations conservatives dues à l’effet lunaire et à l’aplatissement de la Terre àses pôles. Notre approche est basée sur des techniques moyennisation appliquées sur le système issu du principedu maximum. Nous donnons des résultats de convergence entre le système moyenné et le système non moyenné.Enfin, nous simulons les trajectoires du système non moyennée en utilisant les solutions du système moyennépour initialiser des méthodes numériques indirectes / The first part of this work is devoted to the study of the swimming at low Reynolds number where we consider a2-link swimmer to model the motion of a Copepod and the seminal model of the Purcell Three-link swimmer. Wepropose a geometric and numerical approach using optimal control theory assuming that the motion occursminimizing the energy dissipated by the drag fluid forces related with a concept of efficiency of a stroke. TheMaximum Principle is used to compute periodic controls considered as minimizing control using propertransversality conditions, in relation with periodicity, minimizing the energy dissipated for a fixed displacement ormaximizing the efficiency of a stroke. These problems fall into the framework of sub-Riemannian geometry whichprovides efficient techniques to tackle these problems : the nilpotent approximation is used to compute strokeswith small amplitudes which are continued numerically for the true system. Second order optimality, necessary orsufficient, are presented to select weak minimizers in the framework of periodic optimal controls.In the second part, we study the motion of a controlled spacecraft in a central field taking into account thegravitational interaction of the Moon and the oblateness of the Earth. Our purpose is to study the time minimalorbital transfer problem with low thrust. Due to the small control amplitude, our approach is to define anaveraged system from the Maximum Principle and study the related approximations to the non averaged system.We provide proofs of convergence and give numerical results where we use the averaged system to solve the nonaveraged system using indirect method
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Flerfamiljshus självförsörjande på solenergi : En jämförelse av olika kombinationer av PVT, solceller och solfångare i ett hybridsystemManjikian, Saro, Lundgren, Pauline January 2020 (has links)
The rise in population causes serious issues in larger cities since the electrical grid is becoming overloaded. Simultaneously, the demand on more sustainable energy production and the use of renewable energy sources increase. Renewable energy based off-grid electrical systems are a possible solution to decrease the magnitude of these issues. The purpose of this thesis is to compare solar cells, solar thermal collectors and PVT (Photovoltaic thermal hybrid solar collectors) and design the most suitable combination of solar panels for a selfsufficient multi-family house in Jönköping, Sweden. The solar panels were compared from a cost and energy production perspective, then a suitable renewable energy system with all three types of panels was constructed and optimized using Opti-CE, which is a MATLABbased software. During the course of this thesis, an interview was made with Hans-Olof Nilsson who is a co-founder of Nilsson Energy and owner of a self-sufficient off-grid house. The results show that PVT-panels have higher energy production per area and 22% higher LCC (life cycle cost) than regular solar cells in combination with solar thermal collectors. Optimization results indicate that the house cannot be self-sufficient by installing solar panels on the given roof area only, rather the area of installed solar collectors should be increased to a minimum of 1497𝑚2 . With the given roof area of 900𝑚2 the house can only be self-sufficient a maximum of 75% of the time. The results also indicate that the introduction of compact systems with the simultaneous decrease of cost will make renewable off-grid energy systems more attractive in the future.
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Toward an energy self-sufficient paint shopMohammadpour, Violet, Hane, Oskar January 2020 (has links)
As manufacturing is creating welfare and prosperity, it is important for humankind. Nevertheless, manufacturing is causing the depletion of natural resources, environmental burdens affecting the health of animals, humans and eco-systems, and social conflicts. Thus, it is essential to implement sustainability into manufacturing. Paint shops are however known for being liable for a big part of the large energy consumptions within manufacturing. Therefore, it is necessary to investigate what cost-effective solutions can be implemented in paint shops in order to reduce the energy consumption in a sustainable manner. Hence, the aim of this study was to, from a manufacturing perspective identify possible cost-effective solutions for lowering energy consumption within paint shops. The aim was further divided into two research questions: • RQ1: What are the enablers for energy efficient paint shops? • RQ2: What are the challenges for energy efficient paint shops? The research approach used to answer the aim and research questions were a literature review and a case study. The literature review was performed to get a deeper understanding of the subject and was then complimented with the findings from the case study. The case study was performed at the paint shop of a global automotive manufacturing company in Sweden, which currently have a high energy consumption. The enablers identified were (1) implementation of solar photovoltaic, and an energy storage system, which enables an environmentally friendly way of generating energy on-site and store excess energy for later use. The energy storage system can also be used to save money by utilizing the fluctuating electricity market prices, charging the battery when the energy price is at its lowest. (2) Implementation of an UV-curing system and paint, which is an environmentally harmless method of curing paint. (3) Reducing or disabling the heating, ventilation and air conditioning system of a building when it is not a necessity. (4) Workers commitment and motivation towards sustainability, to ensure everyone’s participation. The challenges identified were (1) the expensiveness of sustainability, allocating and prioritizing it in budgets is challenging for a company since profitability is always a major concern that often overshadows sustainability. (2) The risk of modifying the processes within the paint shop, as the consequences are unexplored. (3) In its current state, the energy consumption of the paint shop is very high, it is hence difficult to provide the whole paint shop with solely solar photovoltaic. (4) An energy storage system requires space and freeing up that space is a challenge without reconstructing existing facilities. (5) With implementation of UV- curing, the paint used must be curable with UV-light. Additionally, complex three-dimensional shapes make it challenging to properly cure evenly with UV-curing. (6) It is not guaranteed whether it is possible to completely shut down heating, ventilation and air conditioning since industrial equipment in general is designed to always run. (7) Sustainability is not a focus and even if it is increasingly requested by society, the commitment of companies is experienced as low. It is challenging to motivate all the employees to work towards sustainability and find ways to always keep sustainability in mind and to prioritize it over other alternatives.
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Contributions in interval optimization and interval optimal control /Villanueva, Fabiola Roxana. January 2020 (has links)
Orientador: Valeriano Antunes de Oliveira / Resumo: Neste trabalho, primeiramente, serão apresentados problemas de otimização nos quais a função objetivo é de múltiplas variáveis e de valor intervalar e as restrições de desigualdade são dadas por funcionais clássicos, isto é, de valor real. Serão dadas as condições de otimalidade usando a E−diferenciabilidade e, depois, a gH−diferenciabilidade total das funções com valor intervalar de várias variáveis. As condições necessárias de otimalidade usando a gH−diferenciabilidade total são do tipo KKT e as suficientes são do tipo de convexidade generalizada. Em seguida, serão estabelecidos problemas de controle ótimo nos quais a funçãao objetivo também é com valor intervalar de múltiplas variáveis e as restrições estão na forma de desigualdades e igualdades clássicas. Serão fornecidas as condições de otimalidade usando o conceito de Lipschitz para funções intervalares de várias variáveis e, logo, a gH−diferenciabilidade total das funções com valor intervalar de várias variáveis. As condições necessárias de otimalidade, usando a gH−diferenciabilidade total, estão na forma do célebre Princípio do Máximo de Pontryagin, mas desta vez na versão intervalar. / Abstract: In this work, firstly, it will be presented optimization problems in which the objective function is interval−valued of multiple variables and the inequality constraints are given by classical functionals, that is, real−valued ones. It will be given the optimality conditions using the E−differentiability and then the total gH−differentiability of interval−valued functions of several variables. The necessary optimality conditions using the total gH−differentiability are of KKT−type and the sufficient ones are of generalized convexity type. Next, it will be established optimal control problems in which the objective function is also interval−valued of multiple variables and the constraints are in the form of classical inequalities and equalities. It will be furnished the optimality conditions using the Lipschitz concept for interval−valued functions of several variables and then the total gH−differentiability of interval−valued functions of several variables. The necessary optimality conditions using the total gH−differentiability is in the form of the celebrated local Pontryagin Maximum Principle, but this time in the intervalar version. / Doutor
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Self-sufficient oscillating microsystem at low Reynolds numbersAkbar, Farzin 21 December 2022 (has links)
This work is inspired by the peculiar behavior of the natural systems, namely the ability to produce self-sustained oscillations in the level of tens of Hertz in constant ambient conditions. This feature is one of the key signatures prescribed to living organisms. The firing rate of neuronal cells, a pulsating heart, or the beating of cilia and flagella are among many biological examples that possess amazing functionalities and unprecedented intelligence solely relying on bio-electro-chemical processes. Exploring shapeable polymeric technologies, new self-oscillating artificial microsystems were developed within this thesis. These microsystems rely on the novel nonlinear architecture that exhibits a negative differential resistance (NDR) within the parametric response that enables periodic oscillations. These systems are made of polymers and metals and were microfabricated in a planar fashion. The electrochemically deposited ionic electroactive polymers act as actuators of the system. Upon the self-assembly process, due to the interlayer strains, the planar device transforms into a three-dimensional soft nonlinear system that is able to perform self-sustained relaxation oscillations when subjected to a constant electric field while consuming extremely low powers (as low as several microwatts). The parameters of these systems were tuned for a high oscillation amplitude and frequency. This electro-mechanical parametric relaxation oscillator (EMPRO) can generate a rhythmic motion at stroke frequencies that are biologically relevant reaching up to ~95 Hz. The EMPRO oscillations at high frequencies generate a flow in the surrounding liquid, which was observed in the form of vortices around the micro actuators. This flow was further studied in ex-vivo conditions by measuring Doppler shifts of ultrasound waves. The EMPRO was made autonomous by integrating an electrochemical voltaic cell. Four different electrochemical batteries were tested to match the power consumption of the EMPRO system and electrochemical compatibility of the surrounding media. An Ag-Mg primary cell was then integrated with the EMPRO for autonomous operation without the need for external power sources, cables or controllers. This biomimicking self-powered self-sustaining oscillating microsystem is envisioned to be useful in novel application scenarios operating at low Reynolds numbers in biologically relevant conditions. Furthermore, as the system is electromechanical in nature, it could be integrated with electronic components such as sensors and communication devices in the next generation of autonomous microsystems.:
Table of contents
Acronyms 7
1 Introduction 8
1.1 Motivation 9
1.2 Objectives 9
1.3 Thesis organization 10
2 Background 12
2.1 A brief review on nonlinear self-oscillation 12
2.2 Self-oscillating biological systems 13
2.3 Stimuli responsive materials 15
2.3.1 Electroactive polymers in electrochemical cells 16
2.3.2 Sources of electrical field for electroactive polymers 24
2.4 Self-oscillating synthetic systems 27
2.5 Movement in low Reynolds number regime 33
3 Materials and methods 38
3.1 Deposition methods 38
3.1.1 Photolithography 38
3.1.2 Plasma sputtering 41
3.1.3 Atomic layer deposition 42
3.1.4 Electrochemical polymerization 44
3.2 Shapeable polymeric platform technology 46
3.2.1 Sacrificial layer 46
3.2.2 Hydrogel swelling layer 47
3.2.3 Polyimide reinforcing layer 48
3.3 Characterization methods 49
3.3.1 Profilometry 49
3.3.2 Scanning electron and focused ion beam microscopy 50
3.3.3 Cyclic Voltammetry 52
3.3.4 Ultrasound and Doppler shift measurements 53
4 Electromechanical Parametric Relaxation Oscillators (EMPROs) 56
4.1 Relaxation oscillation in EMPROs 56
4.2 Theory of EMPRO relaxation oscillations 61
4.3 Realization of EMPROs 67
4.3.1 Design parameters of EMPROs 67
4.3.2 EMPRO on-chip battery integration 71
4.4 Fabrication of autonomous EMPROs 76
5 EMPRO performances 84
5.1 Externally biased EMPROs 84
5.2 Autonomous EMPROs 95
6 Conclusions and outlook 98
6.1 Outlook 99
Bibliography i
List of Figures and Tables xi
Versicherung xiii
Acknowledgements xiv
Scientific publications and contributions xvi
Theses xvii
Curriculum Vitae xix
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Klimaneutraler Gebäudebestand durch Pauschalmiete?: Erfahrungen bei solarer Eigenversorgung inklusive SpeicherGäbler, Andreas, Fleischmann, Undine, Storch, Thomas, Fieback, Tobias M. 28 April 2023 (has links)
Der 2. Präsenz- Workshop des Forschungsprojektes „EVERSOL-MFH“ fand diesmal unter besonderen Voraussetzungen bei der eG Wohnen 1902 in Cottbus statt. In direkter Nachbarschaft zu den im Projekt untersuchten Sonnenhäusern kamen ca. 50 Teilnehmer aus Forschung, Wohnungswirtschaft und Planungsbüros mit gebührendem Abstand zusammen. Zusätzlich konnten an zwei Tagen jeweils weitere fast 20 Interessierte der Onlineübertragung aller Vorträge folgen und sich so auch an den anschließenden Diskussionen über den Chat beteiligen. Diese besondere Herausforderung gelang nach anfänglichen Startschwierigkeiten und wird für folgende Workshops als interessante Zusatzoption geplant.
Dank vieler Gastbeiträge wurde insgesamt eine reiche Vortragsvielfalt rund um den
Themenschwerpunkt “Bauen der Zukunft“ vorgestellt:
• Mietmodelle und rechtliche Hürden
• Neue Geschäftsfelder für die Wohnungswirtschaft
• Mieterbefragungen mit Blick auf zukünftige Herausforderungen
• Vorstellung von Messdaten und Nutzereinfluss bei Pauschalmiete
• Sinnvolle Energieversorgungssysteme für das Mehrfamilienhaus, Status quo bei der Solarthermie und Praxisbeispielen
• Alternative Sanierungsstrategien und PV-Fassaden mit Eigennutzung
Im vorliegenden Tagungsband sind freigegebene Vorträge sowie einzelne Inhalte des Workshops noch einmal tiefergehend dargestellt. Weitere Informationen zum Workshop sowie zum EVERSOL-Projekt sind auf der Projekthomepage unter https://eversol.iwtt.tu-freiberg.de/workshop-2020.html zu finden.:Liste der Herausgeber .......................................................................................... 5
Danksagung ......................................................................................................... 7
Zusammenfassung ............................................................................................... 9
1. Mit Low Tech zu High Savings – warum reduzierte Gebäudetechnik mit autarkem
Energiekonzept im Wohnungsbau die Zukunft ist ............................................... 10
2. Pauschalmieten in der WoWi – ein ökonomisches Anreizmodell? ................... 12
3. Energiekennwerte und Nutzereinfluss zweier teilautarker Mehrfamilienhäuser über 1 ½ Jahre Monitoring .................................................................................. 16
4. Neue Geschäftsfelder für die Wohnungswirtschaft- Möglichkeiten und Chancen am Projektbeispiel Winner .................................................................................. 26
5. Wärmepumpe & PV = sinnvolle Energieversorgung im Mehrfamilienhaus? .... 30
6. Energiesprong – Serielles Sanieren von Mehrfamilienhäusern....................... 42
7. Ergebnisse der Mieterbefragungen der Sonnenhäuser vor dem Hintergrund
zukünftiger Smart-Home Gebäude ..................................................................... 46
8. Status quo Solarthermie – Ertragskontrolle und neueste Entwicklungen ....... 52
9. WINNER – Projekt .......................................................................................... 60
10. Solarenergie auf Wohnungsebene – heute die Stadt von morgen bauen ... 64
Fazit und Ausblick Eversol Workshop ................................................................ 66
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Bydraes tot die oplossing van die veralgemeende knapsakprobleemVenter, Geertien 06 February 2013 (has links)
Text in Afikaans / In this thesis contributions to the solution of the generalised knapsack problem are given and discussed.
Attention is given to problems with functions that are calculable but not necessarily in a closed form.
Algorithms and test problems can be used for problems with closed-form functions as well.
The focus is on the development of good heuristics and not on exact algorithms. Heuristics must be
investigated and good test problems must be designed. A measure of convexity for convex functions
is developed and adapted for concave functions. A test problem generator makes use of this measure
of convexity to create challenging test problems for the concave, convex and mixed knapsack problems.
Four easy-to-interpret characteristics of an S-function are used to create test problems for the S-shaped
as well as the generalised knapsack problem.
The in
uence of the size of the problem and the funding ratio on the speed and the accuracy of the
algorithms are investigated. When applicable, the in
uence of the interval length ratio and the ratio of
concave functions to the total number of functions is also investigated.
The Karush-Kuhn-Tucker conditions play an important role in the development of the algorithms. Suf-
cient conditions for optimality for the convex knapsack problem with xed interval lengths is given
and proved. For the general convex knapsack problem, the key theorem, which contains the stronger
necessary conditions, is given and proved. This proof is so powerful that it can be used to proof the
adapted key theorems for the mixed, S-shaped and the generalised knapsack problems as well.
The exact search-lambda algorithm is developed for the concave knapsack problem with functions that
are not in a closed form. This algorithm is used in the algorithms to solve the mixed and S-shaped
knapsack problems. The exact one-step algorithm is developed for the convex knapsack problem with
xed interval length. This algorithm is O(n). The general convex knapsack problem is solved by using
the pivot algorithm which is O(n2). Optimality cannot be proven but in all cases the optimal solution
was found and for all practical reasons this problem will be considered as being concluded. A good heuristic is developed for the mixed knapsack problem. Further research can be done on this
heuristic as well as on the S-shaped and generalised knapsack problems. / Mathematical Sciences / D. Phil. (Operasionele Navorsing)
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Integration and Simulation of a Bitumen Upgrading Facility and an IGCC Process with Carbon CaptureEl Gemayel, Gemayel 19 September 2012 (has links)
Hydrocracking and hydrotreating are bitumen upgrading technologies designed to enhance fuel quality by decreasing its density, viscosity, boiling point and heteroatom content via hydrogen addition. The aim of this thesis is to model and simulate an upgrading and integrated gasification combined cycle then to evaluate the feasibility of integrating slurry hydrocracking, trickle-bed hydrotreating and residue gasification using the Aspen HYSYS® simulation software. The close-coupling of the bitumen upgrading facilities with gasification should lead to a hydrogen, steam and power self-sufficient upgrading facility with CO2 capture. Hydrocracker residue is first withdrawn from a 100,000 BPD Athabasca bitumen upgrading facility, characterized via ultimate analysis and then fed to a gasification unit where it produces hydrogen that is partially recycled to the hydrocracker and hydrotreaters and partially burned for power production in a high hydrogen combined cycle unit. The integrated design is simulated for a base case of 90% carbon capture utilizing a monoethanolamine (MEA) solvent, and compared to 65% and no carbon capture scenarios. The hydrogen production of the gasification process is evaluated in terms of hydrocracker residue and auxiliary petroleum coke feeds. The power production is determined for various carbon capture cases and for an optimal hydrocracking operation. Hence, the feasibility of the integration of the upgrading process and the IGCC resides in meeting the hydrogen demand of the upgrading facility while producing enough steam and electricity for a power and energy self-sufficient operation, regardless of the extent of carbon capture.
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Integration and Simulation of a Bitumen Upgrading Facility and an IGCC Process with Carbon CaptureEl Gemayel, Gemayel 19 September 2012 (has links)
Hydrocracking and hydrotreating are bitumen upgrading technologies designed to enhance fuel quality by decreasing its density, viscosity, boiling point and heteroatom content via hydrogen addition. The aim of this thesis is to model and simulate an upgrading and integrated gasification combined cycle then to evaluate the feasibility of integrating slurry hydrocracking, trickle-bed hydrotreating and residue gasification using the Aspen HYSYS® simulation software. The close-coupling of the bitumen upgrading facilities with gasification should lead to a hydrogen, steam and power self-sufficient upgrading facility with CO2 capture. Hydrocracker residue is first withdrawn from a 100,000 BPD Athabasca bitumen upgrading facility, characterized via ultimate analysis and then fed to a gasification unit where it produces hydrogen that is partially recycled to the hydrocracker and hydrotreaters and partially burned for power production in a high hydrogen combined cycle unit. The integrated design is simulated for a base case of 90% carbon capture utilizing a monoethanolamine (MEA) solvent, and compared to 65% and no carbon capture scenarios. The hydrogen production of the gasification process is evaluated in terms of hydrocracker residue and auxiliary petroleum coke feeds. The power production is determined for various carbon capture cases and for an optimal hydrocracking operation. Hence, the feasibility of the integration of the upgrading process and the IGCC resides in meeting the hydrogen demand of the upgrading facility while producing enough steam and electricity for a power and energy self-sufficient operation, regardless of the extent of carbon capture.
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