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Adaptive filtering techniques are used in a wide range of applications, including echo cancellation, adaptive equalization, adaptive noise cancellation, and adaptive beamforming. The performance of an adaptive filtering algorithm is evaluated based on its convergence rate, misadjustment, computational requirements, and numerical robustness. We attempt to improve the performance by developing new adaptation algorithms and by using "unconventional" structures for adaptive filters. Part I of this dissertation presents a new adaptation algorithm, which we have termed the Normalized LMS algorithm with Orthogonal Correction Factors (NLMS-OCF). The NLMS-OCF algorithm updates the adaptive filter coefficients (weights) on the basis of multiple input signal vectors, while NLMS updates the weights on the basis of a single input vector. The well-known Affine Projection Algorithm (APA) is a special case of our NLMS-OCF algorithm. We derive convergence and tracking properties of NLMS-OCF using a simple model for the input vector. Our analysis shows that the convergence rate of NLMS-OCF (and also APA) is exponential and that it improves with an increase in the number of input signal vectors used for adaptation. While we show that, in theory, the misadjustment of the APA class is independent of the number of vectors used for adaptation, simulation results show a weak dependence. For white input the mean squared error drops by 20 dB in about 5N/(M+1) iterations, where N is the number of taps in the adaptive filter and (M+1) is the number of vectors used for adaptation. The dependence of the steady-state error and of the tracking properties on the three user-selectable parameters, namely step size, number of vectors used for adaptation (M+1), and input vector delay D used for adaptation, is discussed. While the lag error depends on all of the above parameters, the fluctuation error depends only on step size. Increasing D results in a linear increase in the lag error and hence the total steady-state mean-squared error. The optimum choices for step size and M are derived. Simulation results are provided to corroborate our analytical results. We also derive a fast version of our NLMS-OCF algorithm that has a complexity of O(NM). The fast version of the algorithm performs orthogonalization using a forward-backward prediction lattice. We demonstrate the advantages of using NLMS-OCF in a practical application, namely stereophonic acoustic echo cancellation. We find that NLMS-OCF can provide faster convergence, as well as better echo rejection, than the widely used APA. While the first part of this dissertation attempts to improve adaptive filter performance by refining the adaptation algorithm, the second part of this work looks at improving the convergence rate by using different structures. From an abstract viewpoint, the parameterization we decide to use has no special significance, other than serving as a vehicle to arrive at a good input-output description of the system. However, from a practical viewpoint, the parameterization decides how easy it is to numerically minimize the cost function that the adaptive filter is attempting to minimize. A balanced realization is known to minimize the parameter sensitivity as well as the condition number for Grammians. Furthermore, a balanced realization is useful in model order reduction. These properties of the balanced realization make it an attractive candidate as a structure for adaptive filtering. We propose an adaptive filtering algorithm based on balanced realizations. The third part of this dissertation proposes a unit-norm-constrained equation-error based adaptive IIR filtering algorithm. Minimizing the equation error subject to the unit-norm constraint yields an unbiased estimate for the parameters of a system, if the measurement noise is white. The proposed algorithm uses the hyper-spherical transformation to convert this constrained optimization problem into an unconstrained optimization problem. It is shown that the hyper-spherical transformation does not introduce any new minima in the equation error surface. Hence, simple gradient-based algorithms converge to the global minimum. Simulation results indicate that the proposed algorithm provides an unbiased estimate of the system parameters. / Ph. D.

[EN] The aim of this work is to design new acoustic devices based on arrangements of scattering units. First, the use of sonic crystals as noise barriers for traffic noise control is comprehensively analyzed. Due to the limitations of the conventional structures based on rigid scatterers, the inclusion of absorbing elements is proposed. Two different types of absorbers are here considered: porous materials and microperforated plates. In the first case, the attenuation characteristics of barriers made with cylinders containing rubber crumb is analyzed. The second proposal is based on the construction of cylindrical microperforated shells. Analytical approaches modelling the behavior of the barriers have been developed in both cases. These models show a satisfactory agreement with the corresponding experimental realizations. Finally, it is performed an optimization process in order to obtain efficient sound barriers intended to attenuate traffic noise. Another application considered in this work is the construction of cloaks to render objects acoustically invisible. In particular, cloaks made with rigid inclusions are designed to operate with airborne sound. The first proposal consists of a cloak that utilizes the temperature of the background to control the properties of the effective medium. In addition, two and three-dimensional cloaks have been developed through the scattering cancellation technique. These devices have been designed by means of an optimization procedure and their performance has been experimentally demonstrated. / [ES] El objetivo de este trabajo es el diseño de nuevos dispositivos acústicos basados en disposiciones de centros de dispersión. En primer lugar, el uso de cristales sónicos como barreras acústicas para el control de ruido de tráfico es analizado en detalle. Debido a las limitaciones que presentan las estructuras convencionales basadas en centros de dispersión rígidos, se propone la inclusión de elementos absorbentes en los mismos. Se han considerado dos tipos distintos de absorbente: materiales porosos y placas microperforadas. En el primer caso se analizan las propiedades atenuadoras de barreras formadas por cilindros que contienen granza de caucho. La segunda solución se basa en la construcción de coronas microperforadas. En ambos casos se han desarrollado modelos analíticos que permiten determinar el comportamiento de las barreras. Dichos modelos muestran un acuerdo satisfactorio con las correspondientes realizaciones experimentales. Finalmente se ha realizado un proceso de optimización con objeto de obtener barreras eficientes para la atenuación de ruido de tráfico. Otra aplicación considerada en este trabajo es el desarrollo de dispositivos de invisibilidad acústica. Concretamente se pretenden diseñar mantos constituidos con elementos rígidos para ondas acústicas en aire. La primera propuesta consiste en un manto que utiliza la temperatura del medio externo para controlar sus propiedades efectivas. Además se han desarrollado mantos en dos y tres dimensiones a través de la técnica de cancelación de la dispersión. Los diseños han sido realizados por medio de un proceso de optimización y su funcionamiento ha sido demostrado experimentalmente. / [CA] L'objectiu d'aquest treball és el disseny de nous dispositius acústics basats en disposicions de centres de dispersió. En primer lloc, l'ús de vidres sònics com barreres acústiques per al control de soroll de trànsit és analitzat en detall. A causa de les limitacions que presenten les estructures convencionals basades en centres de dispersió rígids, es proposa la inclusió d'elements absorbents en els mateixos. S'han considerat dos tipus diferents de absorbent: materials porosos i plaques microperforades. En el primer cas s'analitzen les propietats atenuadores de barreres formades per cilindres que contenen gransa de cautxú. La segona solució es basa en la construcció de corones microperforades. En tots dos casos s'han desenvolupat models analítics que permeten determinar el comportament de les barreres. Aquests models mostren un acord satisfactori amb les corresponents realitzacions experimentals. Finalment s'ha realitzat un procés d'optimització per tal d'obtenir barreres eficients per l'atenuació de soroll de trànsit. Una altra aplicació considerada en aquest treball és el desenvolupament de dispositius d'invisibilitat acústica. Concretament es pretenen dissenyar mantells constituïts amb elements rígids per ones acústiques en aire. La primera proposta consisteix en un mantell que utilitza la temperatura del medi extern per controlar les seves propietats efectives. A més s'han desenvolupat mantells en dues i tres dimensions a través de la tècnica de cancel·lació de la dispersió. Els dissenys han estat realitzats per mitjà d'un procés d'optimització i el seu funcionament ha estat demostrat experimentalment. / García Chocano, VM. (2015). New devices for noise control and acoustic cloaking [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/53026 / Premios Extraordinarios de tesis doctorales

It is now more than two years since the new Civil Code (OZ), which unified the previous predominantly two-way regulation of the discharge of obligations in one single codex, became effective. As a follow-up to this legally significant event, the focus of my PhD thesis (dissertation) has been on analyzing the resulting changes in comparison with the foregoing legal regulation of the Civil Code and the Commercial Code, including a deliberation on whether such changes have been positive or, alternatively, whether the new regulation can be reproached for certain shortcomings. Although the regulation of OZ which deals with the termination of obligations due to unilateral legal act (such as satisfaction/fulfillment of an obligation (in Czech: "splnění"), deposition in court custody (in Czech: "složení do soudní úschovy"), withdrawal from a contract (in Czech: "odstoupení od smlouvy"), contract cancellation fee (in Czech: "odstupné"), cancellation/termination of a contract by a notice of cancellation/termination (in Czech: "výpověď smlouvy"), and unilateral set-off (in Czech: "jednostranné započtení")) mostly follows up the preceding regulation, it also introduces certain new elements. These new elements evidently intended both to remove certain issues of smaller relevance resulting from the current...

本研究主要針對我國上市櫃輔導之制度，探討撤銷上市(櫃)輔導公司之中，獲准上市(櫃)之公開發行公司，與其他自願撤銷輔導上市櫃之公開發行公司相較，於撤銷輔導上市櫃之前二年至後二年的研究期間，兩者之間的盈餘品質是否存在差異。 實證結果顯示，以損失認列時效性迴歸模型分析時，獲准上市(櫃)之公開發行公司較自願撤銷輔導上市櫃之公開發行公司有較佳的盈餘品質；以盈餘時效性迴歸模型分析時，自願撤銷輔導上市櫃之公開發行公司較獲准上市(櫃)之公開發行公司有較佳的盈餘品質。本研究推論此分歧結果，由我國臺灣證券交易所股份有限公司有價證券上市審查準則與財團法人中華民國證券櫃檯買賣中心證券商營業處所買賣有價證券審查準則對於申請上市(櫃)之獲利門檻要求所造成。 / Based on regulations on listing guidance released by the Taiwan Stock Exchange Corporation (TSEC) mission, this study investigates the difference in earnings quality between firms that voluntarily cancel their listing guidance applications and firm that complete their initial public offerings (IPOs) over the period of two years prior to the cancellation and two years after the cancellation of listing guidance application. The results show that, under timeliness in loss recognition regression model, using a two-year duration prior to the IPO or listing guidance application cancellation for research period, the earnings quality of IPO firms over the two-year-period prior to their IPOs is better than that of firms voluntarily cancelled their listing guidance applications. On the contrary, under timeliness in earnings regression model, earnings quality of firms cancelled their listing guidance application voluntarily is better than that of the IPO firms. The empirical evidence thus suggests that the inconsistence on earnings quality measured in terms of loss and earnings recognition may due to the profitability threshold imposed by TSEC and GreTai Securities Market on rules governing the review of stock listings.

Delay in commercial commitments and its consequences The purpose of the thesis is to describe all the aspects of delay in commercial commitments in the law system of the Czech Republic with focus on the consequences a delay may cause. Even though the history of the respective legislation is long and uninterrupted (it basically dates back to the Austrian General Civil Code from 1811), certain cases of indistinct interpretation in every-day use of the rules may still arise and that is the reason for elaborating the research. Legislation, expert interpretation of the legislation, papers from professional journals and a number of judicatures, mostly decisions of the Supreme Court of the Czech Republic, are used to thoroughly analyse the topic. The Czech Commercial Code recognises two general kinds of delay - debtor's delay, which occurs if the debtor does not fulfil their (usually contractual) duties in time and/or properly and creditor's delay, that is initiated by the creditor if they do not accept proper fulfilment from the debtor and that supersedes the debtor's delay, if it may be in place. In case of the debtor's delay the law automatically guarantees the creditor several rights. They have the right to insist on the proper fulfilment to be delivered or they are entitled to cancel the contract, if...

In the presented work we focus on applications of decision problems from combinatorial group theory. Namely we analyse the Shpilrain-Zapata pro- tocol. We give formal proof that small cancellation groups are good platform for the protocol because the word problem is solvable in linear time and they are generic. We also analyse the complexity of the brute force attack on the protocol and show that in a theoretical way the protocol is immune to attack by adversary with arbitrary computing power.

La théorie générale des obligations contractuelles ne traite de la rupture du contrat qu’au travers de la résolution. Elle n’évoque pas non plus la notion de durée du contrat. L’attention des juristes français est ainsi essentiellement portée sur la résolution pour inexécution et sur la résiliation unilatérale fautive du contrat à durée indéterminée. Une autre présentation, plus neutre, est possible : il s’agit d’étudier la sortie du contrat et, plus particulièrement, la possibilité offerte aux parties de prévoir la sortie anticipée de leurs relations contractuelles.Il est alors possible de se rendre compte que la pratique, face aux lacunes de la théorie générale, a su adapter l’existant afin de prendre en compte l’évolution du contrat depuis le début du XIXème siècle. De nombreuses clauses, qui permettent à un contractant de sortir de manière anticipée du contrat, se sont ainsi développées sous des appellations diverses et sont aujourd’hui présentes dans tous les contrats. L’analyse de la jurisprudence fait apparaître que le contentieux qui en résulte, non seulement porte sur des problèmes communs, mais tend à apporter des solutions communes ; à tout le moins perçoit-on la nécessité d’un traitement unitaire. L’étude, repoussant la distinction classique entre la résolution et la résiliation, recherche l’existence d’une unité, cherche à vérifier l’existence de la clause de sortie qui instituerait une faculté de sortir de manière anticipée d’une relation conclue pour une durée déterminée. Pour cela, la clause de sortie est appréhendée comme toute autre clause « autonome ».Dans un premier temps, il faut démontrer l’existence d’un objectif commun de validité. Il est question tout d’abord de faire ressortir la fonction commune des clauses, qui est de prémunir le titulaire de la faculté de sortie contre une atteinte à son intérêt. L’unité se poursuit dans la nature de la clause : issue d’un accord des parties, elle met en place un droit potestatif. Elle prend alors les traits d’une condition résolutoire « moderne », adaptation contemporaine de la modalité de l’obligation prévue par le Code civil.Dans un second temps, une fois qu’elles sont valablement prévues, les clauses de sortie doivent encore répondre à un objectif commun d’efficacité : la sortie s’exerce par acte unilatéral et obéit alors aux règles applicables à ce dernier. Au-delà de ce régime, on peut se rendre compte qu’il existe des modalités communes à toutes les clauses de sortie. Les effets des clauses de sortie, enfin, présentent ou doivent présenter une certaine unité, que la sortie mise en œuvre soit réussie ou qu’elle soit « manquée ». / The general theory of the contractual obligations treats breach of contract only through the “résolution”. It does not mention either the concept of duration of the contract. The attention of the French jurists is mainly focused on the cancellation for non-fulfilment and the offending termination of the agreement without any term. Another presentation, more neutral, is however possible, studying the exit of the contract and, more particularly, the opportunity given to the contracting parties to envisage the exit of their contractual relations.Then it is possible to realize that the practice, against the gaps of the general theory, knew to adapt existing concepts in order to take into consideration the evolution of the contract since the beginning of the 19th century. Thus many clauses, which make it possible to one of the contracting parties to leave the contract, developed under various names and are today present in all the contracts. The analysis of jurisprudence reveals that the litigations which result from it, not only relate to common problems, but also tend to bring common solutions ; at the very least, one perceives the need for a unit treatment. The study, pushing back the classical distinction between the “résolution” and the “résiliation”, seeks the existence of a unit, seeks to check the existence of the exit clause which would institute a faculty to leave in a way anticipated of a relation concluded for one limited duration. For that purpose, the exit clause is approached like any other “autonomous” clause.Initially, it is necessary to show the existence of a common objective of validity. It is question first of all of emphasizing the common function of the clauses, which is to secure the holder of the faculty of exit against a loss of interest. The unit continues in the nature of the clause: resulting from an agreement of the parties, it sets up a “potestative” right. It then takes the features of a “modern” “resolutive condition”, contemporary adaptation of the condition of the obligation envisaged by the Civil code.In the second time, once they are validly provided, the clauses of exit must meet a common aim of effectiveness : the exit is exerted by unilateral act and then obeys the rules applicable in this case. Beyond this mode, one can realize that there exist common conditions to all the clauses of exit. The effects of these clauses, finally, present or must present a certain unit, whether the exit put in work is successful or that it failed.

Esta dissertação tem como objetivo principal o estudo das técnicas de cancelamento de massa, bem como suas aplicações em análise modal experimental. Estas técnicas são utilizadas na redução de determinados erros nos dados de resposta em frequência da estrutura sob estudo. Estes erros são por sua vez causados por fontes adicionais de inércia, tais como acelerômetros e transdutores de força, que são frequentemente utilizados nos ensaios para o levantamento das características dinâmicas da estrutura. As técnicas de cancelamento de massa estudadas neste trabalho são desenvolvidas a partir de uma modelagem das relações de entrada e saída no domínio da frequência, utilizando-se para tanto as Funções de Resposta em Frequência (FRF), bem como conceitos de subestruturação. Os modelos analíticos utilizados no problema de cancelamento de massa são também aplicados na geração de FRFs desconhecidas para a estrutura sob estudo, a partir de um subconjunto de FRFs medidas com massas adicionais acopladas à estrutura. Os métodos estudados são aplicados a dados obtidos através de simulações numéricas em sistemas discretos, bem como a dados experimentais provenientes de ensaios em estruturas simples. Resultados satisfatórios foram obtidos tanto a partir das simulações numéricas quanto na análise experimental para o problema de cancelamento de massa. Na obtenção de FRFs desconhecidas, verificou-se que os modelos teóricos conduzem a resultados satisfatórios em determinadas situações, e que o ruído encontrado em dados experimentais representa um fator detrimental na utilização das técnicas de cancelamento de massa para o propósito de gerar-se FRF desconhecidas a partir de FRF efetivamente medidas na estrutura sob estudo. / The goal of this dissertation is to develop a study on mass cancellation techniques and their applications in experimental modal analysis. These techniques are commonly employed in the reduction of experimental errors on the structure\'s measured frequency response data. Such errors are in turn caused by extra masses such as accelerometer and force transducers, that are utilized on the measurement of the system\'s Frequency Response Functions (FRF). The mass cancellation techniques studied here are developed through frequency domain input and output relationships as well as substructuring concepts. The analytical models employed in the mass cancellation problem are also applied in obtaining unknown FRF from a subset of measured FRF that are measured with extra masses attached to the structure. The methods studied are applied to numerically simulated data from discrete systems, as well as to experimental data coming from modal tests performed on simple structures. Reasonably good results are obtained in either the numerical and experimental analysis for the mass cancellation problem. In obtaining unknown FRF data, it was verified that the models generated reasonable results in some circumstances, and that experimental noise is a major source of error in using these mass cancellation techniques for the purpose of obtaining unmeasured data from a subset of measured FRF.

This master's thesis deals with the design of a differential high-gain transimpedance amplifier in TSMC's 0.18 um mixed signal process that utilizes a DC photodiode current cancellation loop and a switching automatic gain control (AGC) with a bilinear gain curve. The amplifier is designed to satisfy the demands of Optical Coherence Tomography applications where the receiver is expected to measure the envelope power of an amplitude modulated sinusoidal optical signal that incorporates a large DC component. Methods of increasing dynamic range and gain linearity through the use of DC photodiode current cancellation and bilinear gain are explored. Effects of changing DC photodiode current on the overall system response is also demonstrated.