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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.
1

Evolutionary Algorithms In Design

Ciftci, Erhan 01 January 2007 (has links) (PDF)
Evolutionary Structural Optimization (ESO) is a relatively new design tool used to improve and optimise the design of structures. In this method, a few elements of an initial design domain of finite elements are iteratively removed. Such a process is carried out repeatedly until an optimum design is achieved, or until a desired given area or volume is reached. In structural design, there is the demand for the development of design tools and methods that includes optimization. This need is the reason behind the development of methods like Evolutionary Structural Optimization (ESO). It is also this demand that this thesis seeks to satisfy. This thesis develops and examines the program named EVO, with the concept of structural optimization in the ESO process. Taking into account the stiffness and stress constraints, EVO allows a realistic and accurate approach to optimising a model in any given environment. Finally, in verifying the ESO algorithm&rsquo / s and EVO program&rsquo / s usefulness to the practical aspect of design, the work presented herein applies the ESO method to case studies. They concern the optimization of 2-D frames, and the optimization of 3-D spatial frames and beams with the prepared program EVO. Comparisons of these optimised models are then made to those that exist in literature.
2

Executive stock option disclosures by Australian listed companies: an assessment of their nature, extent and association with governance characteristics

Nelson, Jodie Elizabeth January 2007 (has links)
This thesis investigates statutory executive stock option (ESO) disclosures by Australian listed companies, and their nature, extent and association with governance characteristics. The study is motivated by the limited prior Australian studies that find evidence of low levels of compliance with ESO disclosures (Nelson and Percy, 2005), and by the changes in Australia's regulatory environment over the financial years 2001 to 2004. Arising from these motivations, three research questions are addressed: 1) what is the nature and extent of compliance with ESO disclosures in annual reports and does it change over time?, 2) how does corporate governance influence compliance with ESO disclosures?, and 3) what other factors influence compliance with ESO disclosures? Based on prior research and an application of agency theory, the research questions are addressed by systematically evaluating ESO disclosure compliance, and by modelling and testing the governance and other factors associated with companies' disclosure practices over the 2001 to 2004 study period. Within the agency framework, it is argued that effective governance mechanisms mitigate agency costs by decreasing information asymmetry through increased disclosure. Hence it is predicted that internal governance mechanisms, including the effectiveness of the board of directors, the effectiveness of the audit committee, the existence of a compensation committee, and management incentives are associated with the level of compliance with ESO disclosures. In addition, external governance mechanisms are predicted to influence compliance with ESO disclosures. Specifically, it is predicted that firms responded positively to the increased media and regulatory scrutiny on financial reporting practices as a result of major corporate collapses in Australia and the United States. Furthermore, it is predicted that regulatory intervention, in the form of new and comprehensive ESO disclosure requirements, as well as the authoritative guidance on valuing options and active enforcement efforts by ASIC, have contributed to increased levels of compliance. Using a combination of univariate and multivariate procedures, compliance and governance characteristics are tested over the financial years 2001 to 2004, to capture the changes in compliance over time and to examine the hypothesised relationships. The results of this thesis indicate that Australian companies do not fully comply with ESO disclosure requirements. Nevertheless, the results show that overall compliance has increased progressively from 2001 to 2004, suggesting that the increased scrutiny of companies' financial reporting practices following major corporate collapses has motivated companies to increase compliance. Notably, compliance has increased after the introduction of new and more comprehensive disclosure requirements for ESOs, as well as increased authoritative guidance and enforcement efforts by ASIC. However, despite the overall evidence of improvement in compliance levels, the results continue to reveal management's reluctance to disclose ESO information that may be considered sensitive (for example, price and value-related information). The multivariate results indicate that firms with a larger board of directors and a larger audit committee are more likely to encourage greater levels of compliance with ESO disclosures. However, a larger board of directors appears to take a holistic approach to monitoring company activities by encouraging higher overall compliance rather than focusing on specific, sensitive disclosures. Where a less independent Chairperson is present, the firm is more likely to disclose more sensitive information only, indicating a substitution effect whereby firms mitigate the agency problems associated with this lack of independence by increasing sensitive disclosures. Also, where the Chief Executive Officer's remuneration is relatively larger, companies are less forthcoming about ESO information. With respect to the influence of external corporate governance, the findings indicate that companies identified as poor performers by the Australian Shareholders' Association (a measure of external governance) exhibit lower levels of overall compliance, but not compliance with sensitive disclosures. This latter finding suggests that poorly performing firms provide similar levels of sensitive and important information as other firms, possibly to direct attention away from the low performance of the company. Consistent with prior disclosure research, other factors associated with compliance include leverage, where firms that are more highly leveraged disclose more sensitive information in an effort to become more transparent to creditors, thus reducing their monitoring costs. The use of a Big 4 auditor (a proxy for auditor quality) is associated with overall compliance, which indicates that external auditors primarily ensure that the financial report as a whole is compliant with the regulations, rather than identifying sensitive disclosures in detail, particularly where these disclosures may not have a material effect. Lastly, performance (as measured by profit or lossmaking status) is negatively associated with compliance. By investigating in detail the nature and extent of compliance with ESO disclosures over time and its relation to governance characteristics, the findings of this study demonstrate that while companies appear to lack full compliance with ESO disclosures, compliance has increased over time with active regulatory enforcement and assistance and comprehensive disclosure requirements. Of particular interest, is that the nature of compliance illustrates the very low levels of compliance with important, but sensitive, components of the required ESO disclosures. Importantly, the adoption of stronger governance structures appears to enhance compliance with ESO disclosures, including sensitive disclosures. Therefore, the findings of this study have important implications for corporate regulators, standard setters, financial statement preparers, shareholders and other users of financial reports with an interest in ESOs.
3

Análisis psicopedagógico de los alumnos de educación secundaria con problemas de comportamiento en el contexto escolar

Moreno Oliver, Francesc Xavier 26 June 2001 (has links)
Con la presente investigación, pretendemos crear un instrumento diagnóstico capaz de detectar aquellos factores de riesgo más significativos que la literatura científica define como específicos de los problemas de comportamiento en el contexto escolar. Dada la imposibilidad de poder numerar la totalidad de los factores de riesgo, por su extensión, la literatura científica tiende en general y de manera coincidente a numerar los más significativos y específicos del tema, siendo éstos en los que hemos centrado nuestra atención. Es a partir de esta relación de factores de riesgo, a la que hemos hecho mención anteriormente, cuando nos planteamos la manera de poder diagnosticarlos mediante la creación de una batería específica para este fin. La complejidad de esta tarea se ha centrado principalmente en encontrar las pruebas adecuadas para diagnosticar los factores de riesgo específicos de cada dimensión : bioneuropsicológica, social, psicológica y pedagógica, así como la adaptabilidad de estas pruebas a un perfil de alumno que presenta serias resistencias a cualquier intervención diagnóstica. Por otra parte, la elección de las pruebas, todas ellas ya estandarizadas y por tanto previamente fiabilizadas y validadas, para ser incluidas en una batería diagnóstica ha requerido una nueva fiabilización y validación de la propia batería y muy especialmente el poder determinar si este conjunto de pruebas que constituyen la citada batería son capaces de discriminar los factores de riesgo que deseamos diagnosticar. Mediante la experiencia profesional y vistos los resultados del presente estudio, estamos convencidos que los problemas de comportamiento que presentan los alumnos del primer ciclo de la Educación Secundaria Obligatoria (ESO) pueden ser prevenidos o corregidos mediante un diagnóstico preciso de los factores de riesgo que nos indiquen el tipo de intervención multidisciplinar que requiere su tratamiento. Este intento es una aportación novedosa a la literatura educativa que hace referencia a nuestro contexto educativo, puesto que hasta ahora sólo disponemos de investigaciones realizadas allende nuestras fronteras, sobre todo en el ámbito anglosajón y estadounidense, por estudiosos que han investigado adolescentes y sistemas educativos cuyas características, estimamos, no facilitan una extrapolación absoluta con la realidad y condicionantes de nuestros alumnos y las específicidades de nuestro sistema educativo.Hemos acotado nuestra investigación al ámbito definido como "contexto escolar" entendido éste de un modo amplio. Como "contexto escolar" no consideramos exclusivamente el aula o los espacios donde se desarrolla la docencia. Extendemos nuestra preocupación a espacios de índole en principio "no docente-lectiva" (pasillos, vestíbulos, salas de recreo, patios) y a momentos en que el alumno no está inmerso en la actividad docente. / With the present investigation, we seek to create an instrument diagnosis able to detect those more significant factors of risk that the scientific literature defines as specific of the behavior problems in the school context. Given the impossibility of being able to number the entirety of the factors of risk, for their extension, the scientific literature spreads in general and in a coincident way to number the most significant and specific in the topic, being these in those that we have centered our attention. It is starting from this relationship of factors of risk, to which have made mention previously, when we think about the way to be able to diagnose them by means of the creation of a specific battery for this end. The complexity of this task has been centered mainly in finding the appropriate tests to diagnose the specific factors of risk of each dimension: bioneuropsicolÛgica, social, psychological and pedagogic, as well as the adaptability of these tests to student's profile that presents serious resistances to any intervention diagnÛstica. On the other hand, the election of the tests, all them already standardized and therefore previously fiabilizadas and validated, to be included in a battery diagnÛstica it has required a new fiabilizaciÛn and validation of the own battery and very especially the power to determine if this group of tests that you/they constitute the mentioned battery is able to discriminate against the factors of risk that we want to diagnose. By means of the professional and seen experience the results of the present study, we are convinced that the behavior problems that the students of the first cycle of the Obligatory Secondary Education present (THAT) they can be prevented or corrected by means of a precise diagnosis of the factors of risk that you/they indicate us the type of intervention multidisciplinar that requires their treatment. This intent is a novel contribution to the educational literature that makes reference to our educational context, since up to now we only have investigations carried out beyond our frontiers, mainly in the Anglo-Saxon and American environment, for specialists that have investigated adolescents and educational systems whose characteristic, we estimate, they don't facilitate an absolute extrapolation with the reality and our students' conditions and the especÌficidades of our educational system.We have delimited our investigation to the defined environment as context school expert this in a wide way. As school context we don't consider the classroom or the spaces exclusively where the docencia is developed. We extend our concern to nature spaces in principle not educational-lectiva" (corridors, lobbies, recess rooms, patios) and to moments in that the student is not inmerso in the educational activity.
4

On Active Disturbance Rejection Control: Stability Analysis and Applications in Disturbance Decoupling Control

Zheng, Qing 08 October 2009 (has links)
No description available.
5

Otimização topológica de estruturas planas considerando comportamento não linear geométrico / Topology Optimization of 2D Structures under Geometrically Non Linear Behavior

Paulino, Daniele Melo Santos 31 May 2019 (has links)
Este estudo tem como principal objetivo a compreensão de dois dos principais métodos de otimização topológica disponíveis na literatura: o método SIMP e ESO. Estes métodos foram implementados computacionalmente utilizando a linguagem de programação FORTRAN 90. Utiliza-se o Método dos Elementos Finitos (MEF) como parâmetro de solução mecânica neste trabalho, adotando-se a formulação baseada em deslocamentos para elasticidade linear. Ademais, visando avaliar o efeito da não linearidade geométrica na topologia ótima obtida, utiliza-se também o MEF posicional, o qual baseia-se nas posições nodais para solução do sistema não linear. Em conjunto com este método, adota-se a lei constitutiva de Saint-Venant-Kirchhoff, visando considerar os efeitos não lineares. Desta maneira, avalia-se a eficiência dos resultados obtidos por meio da aplicação de exemplos presentes na literatura. Conforme esperado, conclui-se que para exemplos cuja resposta apresenta pequenos deslocamentos, ambas as soluções se sobrepõem. No entanto, em se tratando de problemas em que a não linearidade geométrica tem influência, como estruturas constituídas de baixa densidade, a técnica do MEF posicional apresenta relevância na solução ótima. / This study has as main objective the understanding of two main topology optimization methods available in the literature: the methods SIMP and ESO. These methods were implemented computationally using the FORTRAN 90 programming language. The finite element method (FEM) is used as the mechanical solution parameter in this work, adopting the displacement-based formulation for linear elasticity. In addition, in order to evaluate the effect of geometric non-linearity in the optimal topology obtained, the FEM positional-based formulation is used, which uses the nodal positions for solution of the non-linear system. In conjunction with this method, the constitutive law adopted is the Saint-Venant-Kirchhoff in order to consider the nonlinearity. Hence, benchmarks presented in the literature are used to evaluate the efficiency of the obtained results. As expected, we conclude that the examples subjected to small displacements have similar solutions for both linear and nonlinear behavior. However, when problems that undergo geometrically nonlinear behavior, such as the ones modelled with soft materials, the FEM positional-based formulation has significant influence in the optimal solution.
6

Mètode de Projectes Tecnològics com un entorn favorable d'aprenentatge en el context de la Teoria de l'Activitat, El

Soler Martínez, Albert Josep 23 January 2004 (has links)
Aquesta tesi intenta dotar la matèria de Tecnologia d'ESO i Batxillerat d'unainterpretació psico-pedagògica nova, de tal manera que ens permeti interpretar,entendre i millorar els processes subjacents en 1'adquisició dels continguts deTecnologia.En primer lloc es fa un estudi detallat d'aquesta matèria: especificant els seus significats; indicant els seus continguts i metodologies; trobant els seus trets caracteristics i les seves peculiaritats... S'observa com la manera de treballar a Tecnologia fa que sigui necessari un tractament psico-pedagògic adient a les sevescaracteristíques. També s'observa que existeixen diferències ben marcades dintre la mateixa matèria però entre diferents països, el que ens fara anar amb molta cura sempre que fem comparacions.Després es revisen les investigacions que s'han dut a terme sobre Tecnologia, tant al nostre país com a d'altres llocs, tot salvant les diferències existents sobre la concepció de la Tecnologia a cada país.Es cerca una teoria psico-pedagogica descriptiva que s'ajusti a les peculiaritats de laTecnologia: la "Teoria de la Formació per Etapes de les Accions Mentals", que s'engloba dintre de la Teoria de 1'Activitat. S'avala aquesta idoneïtat obtenint els trets caracteristics de les metodologies de treball de la Tecnologia en especial del Mètode de Projectes i comparant-los amb la Teoria de 1'Activitat. També es trobencomentaris de destacats investigadors d'aquestes teories avalant el seu ús en la interpretació del Mètode de Projectes.Es fa un estudi d'aquesta teoria psico-pedagògica tot centrant-se en aquells elements que més interessen de cara a interpretar aspectes docents a Tecnologia. Es passa despres a 1'analisi exhaustiu del Mètode de Projectes sota la perspectiva de la Teoria de l'Activitat. En primer lloc, d'una manera global, identificant elements i aclarint definicions i conceptes, i despres d'una manera particular, mitjançant la realització d'una investigació. A la investigació docent justifiquem i expliquem tot el treballrealitzat. I per ultim fem un exercici de síntesi de resultats, tant a nivell particular comgeneral, tot intentant enllaçar amb 1'objectiu inicial de reinterpretar 1'aplicació didàcticadel mètode de projectes a Tecnologia de cara a millorar la docencia.
7

Projecte d'intervenció didàctica sobre conjunts històrico-monumentals: creació d'una iconografia comprensiva. Exemplificació del castell templer i hospitaler.

Poblet Romeu, Marcel Joan 05 March 2003 (has links)
La problemàtica objecte d'estudi consisteix fonamentalment en les següents quatre qüestions: el desenvolupament de la Didàctica de la Història i específicament de la Didàctica del Patrimoni; la implementació d'una intervenció en un conjunt monumental (el Castell del Temple de Barberà de la Conca); el fet que la intervenció pròpiament didàctica es limitarà a les construccions medievals (i, per tant, afectarà a les fases corresponents als ordes del Temple i de l'Hospital de Sant Joan de Jerusalem del dit monument); i, en darrer lloc, la voluntat d'obtenir un model d'intervenció en el Patrimoni Arquitectònic i Arqueològic que es pugui utilitzar com a guia en d'altres casos. Els horitzons destinataris del projecte es concreten en l'Ensenyament Secundari Obligatori (ESO) i en el turisme cultural. L'estudi parteix d'unes bases epistemològiques de la Didàctica del Patrimoni fonamentades en autors com ara Altamira, Hernàndez, Pibernat i Santacana. Aquestes bases porten a constatar que no hi ha cap forma d'implementar una Didàctica de la Història vàlida que no parteixi de les fonts, i que el document escrit resulta de més difícil maneig, per la qual cosa sembla convenient donar prioritat a les fonts patrimonials. Les hipòtesis de treball giren al voltant de la idea que la Didàctica del Patrimoni pot donar respostes a un context caracteritzat per una "crisi de l'ensenyament de la Història" al costat d'un interès creixent pel Patrimoni cultural. D'altra banda, es fa especial èmfasi sobre les estratègies didàctiques de caràcter lúdic. L'estudi teòric (històric, arqueològic i didàctic) obre pas a la gènesi d'una iconografia que serà la base per a la implementació d'uns espais per a la presentació del patrimoni (que inclouen un projecte de restauració arquitectònica i un projecte museogràfic centrat en el castell medieval català i en els ordes militars templer i hospitaler), així com d'uns materials didàctics pensats específicament per a l'Ensenyament Secundari Obligatori.
8

"Estilo de socialización parental y fracaso escolar en la eso: una nueva mirada"

Domínguez González, Maria José 10 July 2012 (has links)
El fracàs escolar persisteix en el sistema educatiu com una roca difícil de remoure. En un país desenvolupat com el nostre, on s’han aconseguit quotes d’escolarització plena en les etapes obligatòries, diversos indicadors del fracàs segueixen afectant a un nombre elevat d’alumnes i posen de manifest que, en els darrers anys, els propòsits de reduir-lo de forma significativa i estable s’estan estancant (inclús retrocedint). El sistema educatiu deixa enrere un terç dels alumnes, són els que obtenen resultats desencisadors: aquests alumnes repeteixen curs però els seus nivells de rendiment no milloren, per tant, la mesura estrella per combatre el fracàs es demostra poc eficaç i s’han de crear noves vies d’anàlisi i tractament d’aquesta dificultat vigent. Aquesta tesis pretén explorar la relació que existeix entre l’estil de socialització parental que perceben els fills adolescents i el seu rendiment acadèmic com a alumnes de l’Educació Secundària Obligatòria. En la intersecció d'ambdós fenòmens trobem la hipòtesi que dona consistència a la present recerca: l'estil de socialització parental influeix de forma significativa en el rendiment acadèmic. L’estudi està orientat a la presa de decisions, utilitza dades quantitatives de caràcter transversal i és correlacional. La mostra està composta per 288 alumnes d’un centre de secundària públic de la província de Tarragona i el treball de camp es va realitzar durant el 2n. trimestre del curs 2010/2011. El disseny d’investigació respon a la finalitat de definir fins a quin punt estan influint la variable predictora (estil de socialització parental) en la criteri (resultats acadèmics). El resultat primordial al que s’arriba és que la variable acceptació/implicació dels pares es troba significativament vinculada al rendiment (evidència que deixa al descobert una línia d’actuació familiar de gran potencial). L’estudi aconsegueix confirmar i delimitar la correlació intuïda entre i subratlla l’àmbit familiar com un nou espai de preocupació pedagògica per explicar i intervenir sobre el fracàs escolar. / Students who don't succeed in school are a very persistent problem in our educational system. In our country, with a full level of schooling from 6 to 16 years old, there are different indicators of academic failure that still affect to a quite high number of students. This fact shows that, in the last few years, all the efforts to reduce this problem are not succeeding. One third of our students are left behind by the educational system; their results are discouraging. These students repeat year after year but their performance is not improving. This means that the measures to fight the academic failure are not working and that we have to put into practice new ways of analysis and treatment of this problem. This research explores the relationship between the way children perceive how their parents are educating them (parental socialization style) and his or her academic performance. In the intersection of both phenomena we find our hypothesis: the way parents socialise their children influences significantly their academic performance. This research is orientated to decision taking process, it uses quantitative data and it is a correlational study. Our simple is a group of 288 students from 12 to 16 year old from public schools from Tarragona province. We collected our data during the second trimester of the school year 2010/2011. The aim of the research is to define the level of influence of the predictive variables (parental socialization style) in the criteria variables (academic results). The main result we have found is that parents acceptation/implication appears to be significantly linked to the school performance (this evidence shows a big area for new researches: the family). Our research confirms and frames the correlation between these two variables and underlies the family as a new scenario of pedagogical concern to explain and treat school failure.
9

Frequency-comb stabilized laser sources for absolute distance metrology at the very large telescope interferometer

Schuhler, Nicolas Meyrueis, Patrick. January 2007 (has links) (PDF)
Thèse doctorat : Physique Photonique : Strasbourg 1 : 2006. / Titre provenant de l'écran-titre. Notes bibliogr.
10

Développement d'un modèle numérique de l'instrument MUSE / VLT (Multi Unit Spectroscopic Explorer / Very Large Telescope)

Jarno, Aurélien Allard, Bruno Bacon, Roland. January 2009 (has links)
Thèse doctorat : Dispositifs de l'Electronique Intégrée : Villeurbanne, INSA : 2008. / Titre provenant de l'écran-titre. Bibliogr. p. [127]-132. Contient également 1 article de revue.

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