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31	Observation et commande d'une classe de systèmes non linéaires temps discret / Observation and control of a class of nonlinear discrete-time systems Gasmi, Noussaiba 14 November 2018 (has links) L’analyse et la synthèse des systèmes dynamiques ont connu un développement important au cours des dernières décennies comme l’atteste le nombre considérable des travaux publiés dans ce domaine, et continuent d’être un axe de recherche régulièrement exploré. Si la plupart des travaux concernent les systèmes linéaires et non linéaires temps continu, peu de résultats ont étaient établis dans le cas temps discret. Les travaux de cette thèse portent sur l’observation et la commande d’une classe de systèmes non linéaires à temps discret. Dans un premier temps, le problème de synthèse d’observateur d’état utilisant une fenêtre de mesures glissante est abordé. Des conditions de stabilité et de robustesse moins restrictives sont déduites. Deux classes de systèmes non linéaires à temps discret sont étudiées : les systèmes de type Lipschitz et les systèmes « one-sided Lipschitz ». Ensuite, une approche duale a été explorée afin de déduire une loi de commande stabilisante basée sur un observateur. Les conditions d’existence d’un observateur et d’un contrôleur stabilisant les systèmes étudiés sont formulées sous forme d’un problème d’optimisation LMI. L’efficacité et la validité des approches présentées sont montrées à travers des exemples académiques / The analysis and synthesis of dynamic systems has undergone significant development in recent decades, as illustrated by the considerable number of published works in this field, and continue to be a research theme regularly explored. While most of the existing work concerns linear and nonlinear continuous-time systems, few results have been established in the discrete-time case. This thesis deals with the observation and control of a class of nonlinear discrete-time systems. First, the problem of state observer synthesis using a sliding window of measurements is discussed. Non-restrictive stability and robustness conditions are deduced. Two classes of discrete time nonlinear systems are studied: Lipschitz systems and one-side Lipschitz systems. Then, a dual approach was explored to derive a stabilizing control law based on observer-based state feedback. The conditions for the existence of an observer and a controller stabilizing the studied classes of nonlinear systems are expressed in term of LMI. The effectiveness and validity of the proposed approaches are shown through numerical examples Systèmes à temps discret Systèmes Lipschitz Systèmes « one-sided Lipschitz » Optimisation LMI Stabilité au sens de Lyapunov Filtrage H∞ Approche avec fenêtre glissante Commande basée observateur Commande robuste Critère H∞ Incertitudes paramétriques Discrete-time systems Lipschitz systems One-sided Lipschitz systems LMI optimization Lyapunov Stability H∞ filtering Sliding window approach Observer-based control Robust control H∞ criterion Parametric uncertainties 620.001 185 003.83
32	Αυτόματη μάθηση συντακτικών εξαρτήσεων και ανάπτυξη γραμματικών της ελληνικής γλώσσας / Learning of syntactic dependencies and development of modern Greek grammars Κερμανίδου, Κάτια Λήδα 25 June 2007 (has links) Η παρούσα διατριβή έχει ως σκοπό της, πρώτον, την ανάκτηση συντακτικής πληροφορίας (αναγνώριση συμπληρωμάτων ρημάτων, ανάκτηση πλαισίων υποκατηγοριοποίησης (ΠΥ) ρημάτων, αναγνώριση των ορίων και του είδους των προτάσεων) αυτόματα μέσα από ελληνικά και αγγλικά σώματα κειμένων με την χρήση ποικίλων και καινοτόμων τεχνικών μηχανικής μάθησης και, δεύτερον, την θεωρητική περιγραφή της ελληνικής σύνταξης μέσω τυπικών γλωσσολογικών φορμαλισμών, όπως η γραμματική Ενοποίησης και η γραμματική Φραστικής Δομής Οδηγούμενη από τον Κύριο Όρο. Η διατριβή κινήθηκε πάνω στους εξής καινοτόμους άξονες: 1. Η προεπεξεργασία των σωμάτων κειμένων βασίστηκε σε ελάχιστους γλωσσολογικούς πόρους για να είναι δυνατή η μεταφορά των μεθόδων σε γλώσσες φτωχές σε υποδομή. 2. Η αντιμετώπιση του θορύβου που υπεισέρχεται στα δεδομένα εξ αιτίας της χρήσης ελάχιστων πόρων πραγματοποιείται με Μονόπλευρη Δειγματοληψία. Εντοπίζονται αυτόματα παραδείγματα δεδομένων που δεν προσφέρουν στην μάθηση και αφαιρούνται. Τα τελικά δεδομένα είναι πιο καθαρά και η απόδοση της μάθησης βελτιώνεται πολύ. 3. Αποδεικνύεται η χρησιμότητα της εξαχθείσας πληροφορίας. Η χρησιμότητα των συμπληρωμάτων φαίνεται από την αύξηση της απόδοσης της διαδικασίας ανάκτησης ΠΥ με την χρήση τους. Η χρησιμότητα των εξαγόμενων ΠΥ φαίνεται από την αύξηση της απόδοσης ενός ρηχού συντακτικού αναλυτή με την χρήση τους. 4. Οι μέθοδοι εφαρμόζονται και στα Αγγλικά και στα Ελληνικά για να φανεί η μεταφερσιμότητά τους σε διαφορετικές γλώσσες και για να πραγματοποιηθεί μια ενδιαφέρουσα σχετική σύγκριση ανάμεσα στις δύο γλώσσες. Τα αποτελέσματα είναι πολύ ενθαρρυντικά, συγκρίσιμα με, και σε πολλές περιπτώσεις καλύτερα από, προσεγγίσεις που χρησιμοποιούν εξελιγμένα εργαλεία προεπεξεργασίας. / The thesis aims firstly at the acquisition of syntactic information (detection of verb complements, acquisition of verb subcategorization frames (SF), detection of the boundaries and the semantic type of clauses) automatically from Modern Greek and English text corpora with the use of various state-of-the-art and novel machine learning techniques, and, secondly, at the theoretical description of the Greek syntax through formal grammatical theories like Unification Grammar and Head-driven Phrase Structure Grammar. The thesis has been based on the following novel axes: 1. Corpus pre-processing has been limited to the use of minimum linguistic resources to ensure the portability of the presented methodologies to languages that are poorly equipped with resources. 2. Due to the low pre-processing level, a significant amount of noise appears in the data, which is dealt with One-sided Sampling. Examples that do not contribute to the learning process are detected and removed. The final data set is clean and learning performance improves significantly. 3. The importance of the acquired information is proven. The importance of complements is shown by the improvement in the performance of the SF acquisition process after the incorporation of complement information. The importance of the acquired SF lexicon is shown by its incorporation in a shallow syntactic parser and the increase of the performance of the latter. 4. The methods are applied on Modern Greek and on English to show their portability across different languages and to allow for an interesting rough comparison between the two languages. The results are very satisfactory, comparable to, and in some cases better than, approaches utilizing sophisticated resources for pre-processing. Συμπληρώματα ρημάτων Μηχανική μάθηση Συντακτική ανάλυση 410.285 Natural language processing Verb complements Verb subcategorization frames Machine learning Syntactic processing One-sided sampling Modern Greek grammar development
33	The Myth of Incentive-Based Sales Strategies: an Empirical Analysis Contradicting Prevailing Theories using Data Mining and Hypothesis Testing Techniques Liang, Yidan (Nickia) January 2023 (has links) In recent decades, the use of incentive-based reward programs to foster customer loyalty and promote sales has become prevalent in various industries. While these strategies are widely accepted and implemented, there is a significant gap in empirical studies to ascertain their real-world effectiveness. This thesis embarks on a comprehensive examination into the effectiveness of an online business's reward program, utilizing data from the past five years and employing data mining techniques, including RFM (Recency, Frequency, Monetary) model and clustering algorithms; hypothesis tests are employed to further strengthen the drawn conclusions. Contrary to popular theories, the findings reveal that small incentives such as rewards did not induce significant changes in customer purchasing behavior, nor did they effectively boost sales among rewarded customers. A control group of non-rewarded top-class customers showed more robust purchasing patterns. These unexpected results challenge existing beliefs and call for a critical re-evaluation of current practices in sales promotion and customer loyalty. The research underscores the need for empirically grounded strategies, further exploration into alternative loyalty-building methods, and a recognition of the complex realities influencing customer engagement. Reward Program Reward Evaluation Data Mining RFM Customer Segmentation Clustering K-Means Hypothesis Testing One-Sided T-Test Marketing Effectiveness Incentive-Based Sales Strategy Sales Promotion Business Administration Företagsekonomi
34	Choice deferral, status quo bias, and matching Buturak, Gökhan January 2011 (has links) This thesis consists of three independent papers. They are put in reverse chronological order according to when they were initiated. The first paper, which is a joint work with Özgür Evren, extends the standard rational choice framework with the option to postpone the act of selecting an alternative. In that paper, we propose an axiomatic model of choice over risky prospects that restricts the classical rationality axioms solely to those instances in which the decision maker does not defer. The cardinal approach we follow allows us to identify the preference relation of the decision maker over lotteries, even if the choice data is very scarce due to deferral. Moreover, we also derive the value of deferring choice from a given set of options, which turns out to be an affine utility function over choice sets. At each choice situation, the decision maker compares the utility of each available alternative with that of deferral so as to decide on opting for an alternative immediately. The second paper is a model of status quo bias with choice avoidance. It describes the choice behavior of an otherwise standard decision maker whose choices are affected by the presence of a status quo alternative. The status quo emerges as a temporary choice, which may be reversed upon arrival of new (introspective or objective) information, or upon finding new alternatives. The third paper considers the network formation problem from a matching perspective. In that paper, agents want to link with each other and each has preferences over the subsets of others. We consider various solution concepts regarding the stability of a matching between the agents, establish relations between these concepts under several preference restrictions, and provide sufficient conditions for these solutions to be nonempty. / Diss. Stockholm : Handelshögskolan i Stockholm, 2011 choice theory choice deferral choice avoidance preference for flexibility preference for commitment subjective states anticipated regret status quo bias incomplete preferences one-sided many-to-many matching network formation setwise stable set bargaining set individually rational core weak separability implementation strategy-proofness Pareto efficiency Ekonomisk teori Economics Nationalekonomi
35	Jednostranné gramatiky s nahodilým kontextem / One-Sided Random Context Grammars Zemek, Petr Unknown Date (has links) Tato disertační práce zavádí jednostranné gramatiky s nahodilým kontextem jako řízené gramatiky založené na bezkontextových gramatikách. V těchto gramatikách je ke každému pravidlu přiřazena množina povolujících symbolů a množina zakazujících symbolů a množina pravidel je rozdělena na množinu levých pravidel s nahodilým kontextem a množinu pravých pravidel s nahodilým kontextem . Levým pravidlem s nahodilým kontextem lze přepsat neterminál pokud se všechny povolující symboly vyskytují vlevo od přepisovaného neterminálu a žádný zakazující symbol tam přítomen není. Pravé pravidlo s nahodilým kontextem lze aplikovat analogicky, ale ona kontrola na přítomnost a nepřítomnost symbolů je provedena doprava od přepisovaného neterminálu. Práce je rozdělena na tři části. První část uvádí motivaci za zavedením jednostranných gramatik s nahodilým kontextem a umisťuje materiál pokrytý v této práci do vědeckého kontextu. Poté dává přehled základů teorie formálních jazyků a některých méně známých oblastí, jejichž znalost je nutná pro pochopení studovaného tématu. Druhá část tvoří jádro práce. Formálně definuje jednostranné gramatiky s nahodilým kontextem a studuje je z mnoha pohledů. Mezi studovaná témata patří generativní síla, vztah k jiným typům gramatik, redukce, normální formy, nejlevější derivace, zobecněné a LL verze těchto gramatiky. Třetí část této práce zakončuje diskusi několika poznámkami. Mezi ně patří poznámky týkající se aplikovatelnosti zavedených gramatik v praxi, bibliografie a otevřených problémů.
36	Adaptivní kmitočtový filtr / Adaptive frequency filter Kříž, Petr January 2010 (has links) The aim of this work is to design a filter of the type low–pass of order 5th with Butterworth’s approximation in the range of over-tuning 10 – 100 kHz and if it will be possible so! achieve even higher marginal frequencies. To compare two typical representatives of the frequency filters cascading and non-cascading synthesis from the viewpoint the accuracy of an! approximation function, sensitivity to the tolerance values of components, number of the components (mainly OZ) and viability, especially the possibility of electronic over-tuning in selected frequency range. On the basis of these conditions will be chosen one design, which will be realized later. Further it will be necessary to consider the possibilities of electronic over-tuning and to choose for this over-tuning suitable component, to design user management changes of marginal frequency fm by the help of keyboard + LCD and control application on the PC. For this hardware will be programmed appropriate control software. At the end of this work will be constructed appropriate device, which fullfils requirements written above and will be subjected to the laboratory measurements that verify function of this device. The constructional details of the filter are presented in the enclosure at the end of this work. At the CD are available all materials, which were created during the master’s thesis or which are necessarily concerned.
37	Exploratory study of market entry strategies for digital payment platforms Marcinkowska, Anna January 2018 (has links) The digital payment industry has become one of the fastest evolving markets in the world, but in the wake of its rapid advancement, an ever increasing gap between academic theory and the actual reality of this market widens - and especially so when it comes to entry theory. It is widely acknowledged that the world is moving towards an ever more homogeneous economy, but despite the fact that payment preferences differ greatly from country to country - research on this subject continues to revolve mainly around localized efforts. But as historical inequalities between poor and rich societies continue to dissipate - learning from nations at the forefront of technological advancement increases the likelihood that the developed strategy becomes applicable to an increased number of countries. By selecting a nation most conducive to technological growth, the purpose of this report is to map the present dynamics in its digital payment industry using both recent and traditional market entry theory. However, studies geared towards globalized strategy formulation cannot be assumed as having guaranteed access to internal company-data at all times. So in order to facilitate such studies, the level of dependency on primary data required for conducting such research needs to be understood first, which is why the work in this report is constrained strictly to data of secondary nature. This, not only to further map the characteristics of this market, but also to see how open the market is to public inspection. Ultimately, the academic contribution becomes that of providing a road-map towards adapting currently available market entry theory to suit the rapidly evolving conditions of the digital payment industry from a global perspective and, when failing to do so, the aim is to also explore avenues for further research towards this end goal. Market entry strategy digital payment platform platform network effects first mover late entrant early follower klarna swish paypal seqr wywallet homing costs switching costs internationalization bankid bank-id cashless society timing of entry one-sided two-sided multi-sided NFX cross-side cross side same-side same side subsidy-side subsidy side money-side money side secondary data analysis degrees of navigation navigational degrees content cognitive load application mobile payment mobile wallet Business Administration Företagsekonomi Other Natural Sciences Annan naturvetenskap Övrig annan teknik
38	Beiträge zur expliziten Fehlerabschätzung im zentralen Grenzwertsatz Paditz, Ludwig 04 June 2013 (has links) (PDF) In der Arbeit wird das asymptotische Verhalten von geeignet normierten und zentrierten Summen von Zufallsgrößen untersucht, die entweder unabhängig sind oder im Falle der Abhängigkeit als Martingaldifferenzfolge oder stark multiplikatives System auftreten. Neben der klassischen Summationstheorie werden die Limitierungsverfahren mit einer unendlichen Summationsmatrix oder einer angepaßten Folge von Gewichtsfunktionen betrachtet. Es werden die Methode der charakteristischen Funktionen und besonders die direkte Methode der konjugierten Verteilungsfunktionen weiterentwickelt, um quantitative Aussagen über gleichmäßige und ungleichmäßige Restgliedabschätzungen in zentralen Grenzwertsatz zu beweisen. Die Untersuchungen werden dabei in der Lp-Metrik, 1<p<oo oder p=1 bzw. p=oo, durchgeführt, wobei der Fall p=oo der üblichen sup-Norm entspricht. Darüber hinaus wird im Fall unabhängiger Zufallsgrößen der lokale Grenzwertsatz für Dichten betrachtet. Mittels der elektronischen Datenverarbeitung neue numerische Resultate zu erhalten. Die Arbeit wird abgerundet durch verschiedene Hinweise auf praktische Anwendungen. / In the work the asymptotic behavior of suitably centered and normalized sums of random variables is investigated, which are either independent or occur in the case of dependence as a sequence of martingale differences or a strongly multiplicative system. In addition to the classical theory of summation limiting processes are considered with an infinite summation matrix or an adapted sequence of weighting functions. It will be further developed the method of characteristic functions, and especially the direct method of the conjugate distribution functions to prove quantitative statements about uniform and non-uniform error estimates of the remainder term in central limit theorem. The investigations are realized in the Lp metric, 1 <p <oo or p = 1 or p = oo, where in the case p = oo it is the usual sup-norm. In addition, in the case of independent random variables the local limit theorem for densities is considered. By means of electronic data processing new numerical results are obtained. The work is finished by various references to practical applications. Zentraler Grenzwertsatz Summen unabhängiger Zufallsgrößen Doppelfolge von Zufallssgrößen Martingaldifferenzfolgen stark multiplikative Systeme Zufallsvektoren Zufallselemente Verteilungsfunktion Dichtefunktion charakteristische Funktionen konjugierte Verteilungen zufälliger Index Konvergenzgeschwindigkeit ungleichmäßige Fehlerabschätzung einseitige Momente Pseudomomente abgeschnittene Momente Limitierungsverfahren Lp-Metrik globaler zentraler Grenzwertsatz Ordnung der Konvergenzgeschwindigkeit Fehlerabschätzung mittlere Abweichungen central limit theorem sums of independent random variables triangular arrays of random variables series of independent random variables sequences of martingale differences strongly multiplicative systems random vectors random elements distribution function density function characteristic functions conjugate distributions random index speed of convergence nonuniform error estimate one-sided moments pseudo moments truncated moments limiting methods Lp-metric global central limit theorem nonuniform central limit theorem order of the speed of convergence error estimation moderate deviations ddc:510 rvk:SK 800
39	Statistical Inference Chou, Pei-Hsin 26 June 2008 (has links) In this paper, we will investigate the important properties of three major parts of statistical inference: point estimation, interval estimation and hypothesis testing. For point estimation, we consider the two methods of finding estimators: moment estimators and maximum likelihood estimators, and three methods of evaluating estimators: mean squared error, best unbiased estimators and sufficiency and unbiasedness. For interval estimation, we consider the the general confidence interval, confidence interval in one sample, confidence interval in two samples, sample sizes and finite population correction factors. In hypothesis testing, we consider the theory of testing of hypotheses, testing in one sample, testing in two samples, and the three methods of finding tests: uniformly most powerful test, likelihood ratio test and goodness of fit test. Many examples are used to illustrate their applications. finite population correction factor statistical hypothesis type I error composite hypothesis power Central limit theorem Basu theorem critical value goodness of fit test likelihood ratio test Lehmann-Scheffe theorem complete statistic ancillary statistic P-value type II error Rao-Blackwell theorem simple hypothesis one-sided test two-sided test significance level sufficient statistic alternative hypothesis testing hypothesis null hypothesis rejection region confidence interval confidence level minimum variance unbiased estimator interval estimation uniformly most powerful test Cramer-Rao inequality likelihood function mean square error moment estimator error of estimation point estimation maximum likelihood estimator bias consistent estimator minimal sufficient statistic factorization theorem unbiased estimator statistic most powerful test test statistics Neyman-Pearson lemma decision rule
40	Beiträge zur expliziten Fehlerabschätzung im zentralen Grenzwertsatz Paditz, Ludwig 27 April 1989 (has links) In der Arbeit wird das asymptotische Verhalten von geeignet normierten und zentrierten Summen von Zufallsgrößen untersucht, die entweder unabhängig sind oder im Falle der Abhängigkeit als Martingaldifferenzfolge oder stark multiplikatives System auftreten. Neben der klassischen Summationstheorie werden die Limitierungsverfahren mit einer unendlichen Summationsmatrix oder einer angepaßten Folge von Gewichtsfunktionen betrachtet. Es werden die Methode der charakteristischen Funktionen und besonders die direkte Methode der konjugierten Verteilungsfunktionen weiterentwickelt, um quantitative Aussagen über gleichmäßige und ungleichmäßige Restgliedabschätzungen in zentralen Grenzwertsatz zu beweisen. Die Untersuchungen werden dabei in der Lp-Metrik, 1<p<oo oder p=1 bzw. p=oo, durchgeführt, wobei der Fall p=oo der üblichen sup-Norm entspricht. Darüber hinaus wird im Fall unabhängiger Zufallsgrößen der lokale Grenzwertsatz für Dichten betrachtet. Mittels der elektronischen Datenverarbeitung neue numerische Resultate zu erhalten. Die Arbeit wird abgerundet durch verschiedene Hinweise auf praktische Anwendungen. / In the work the asymptotic behavior of suitably centered and normalized sums of random variables is investigated, which are either independent or occur in the case of dependence as a sequence of martingale differences or a strongly multiplicative system. In addition to the classical theory of summation limiting processes are considered with an infinite summation matrix or an adapted sequence of weighting functions. It will be further developed the method of characteristic functions, and especially the direct method of the conjugate distribution functions to prove quantitative statements about uniform and non-uniform error estimates of the remainder term in central limit theorem. The investigations are realized in the Lp metric, 1 <p <oo or p = 1 or p = oo, where in the case p = oo it is the usual sup-norm. In addition, in the case of independent random variables the local limit theorem for densities is considered. By means of electronic data processing new numerical results are obtained. The work is finished by various references to practical applications. info:eu-repo/classification/ddc/510 ddc:510

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