Submitted to the Faculty of Arts in fulfilment of the requirements for the Degree of Doctor of Philosophy in the Department of General Linguistics at the University of Zululand, 2007. / In almost all the statutory sentences that obtain in the statutes of the University of Zululand and the University of Swaziland respectively, modification and subordination or rather embedding form part of the essential techniques used by the writers to enhance the communicative potential of the sentences. The objective of the study, therefore, was to establish that using adjectival and adverbial information in legal texts does have an effect on the act of reading and interpretation and the resultant meaning on the text. The construction of the sentences in the two statutes favours the study's hypotheses. The first hypothesis is that using adjectival and adverbial information in legal texts significantly enhances clarity and precision of the expression as mediated by the text. The second hypothesis is. that reference both within the nominal group and the verbal group in legal texts is susceptible of further specification. In chapter two, we argue, in Bex's (1996:95) terms, that texts orient themselves to readers in particular ways, and organize their information in ways appropriate to the medium selected and the context in which they occur. We also note that in the construction and interpretation of texts due attention is given to the elements in the language which are capable of encoding various functions and particular realizations of these functions determine the register of the text under consideration (cf. Bex, 1996:95). In our analysis of the statutes of the University of Zululand and the University of Swaziland respectively, we establish that language varies according to the activity in which it plays a part (Leech et al, 1982:10). We also establish that sentences with different structures have different communicative functions and that one important property of a sentence is its communicative potential (Akmajian et al, 1995:229). This communicative potential of sentences, with specific reference to the statutory sentences under discussion, is, as already indicated earlier on, enhanced by using modification both within the nominal group and the verbal group. Thus, it is worth emphasizing that in enhancing the effectiveness and communicative potential of the statutory sentences in order to achieve clarity and precision of the expression, modifying elements carrying adjectival and adverbial information are put to use in constructing the sentences. In consequence thereof, modification which employs non-nuclear constituents is accorded a central role in determining the effectiveness of the sentences whilst the acceptability of the sentences in terms of its grammaticaltty is determined solely by the nuclear constituents. Thus the argument that the occurrence of a modifier is never essential for the internal structure of a noun phrase and that a modifier can be easily omitted without affecting the acceptability of the noun phrase (Aarts and Aarts, 1988:63) is, in our view, not at issue. Our concern is not so much with the acceptability of both reference and predication within the structure of the sentence. Rather, we are concerned with whether the communicative potential or effectiveness of the sentences makes it possible for the communicative intent to be realized as intended. Our analysis of the sentences in the statutes in question, demonstrate that the necessary specification is contained in the modifier and that a modifier has the effect of explicitness and of specifying precisely that which is the point of information (Halliday and Hasan, 1997:96). Our view, therefore, is that although non-nuclear constituents (modifiers) in a sentence are optional, their role of specification cannot go unnoticed since they are tightly integrated into the structure of the clause (cf. Huddleston and Pullum, 2005). This view is corroborated by Akmajian et al's (1995:223) argument that the meaning of a syntactically complex expression is determined by the meaning of its constituents and their grammatical relations. Hence we argue that notwithstanding the fact that nuclear constituents are obligatory for the sentence to be accepted as grammatical, the grammaticality of the sentence as determined by the nuclear constituents does not necessarily translate into its effectiveness as a communicative device of information. It bears repeating, therefore, that in almost all the statutory sentences of the two universities, modification and subordination or rather embedding from part of the essential techniques use by the writers to enhance the communicative potential and effectiveness of the sentences.

Submitted by Rafael Santana (rafael.silvasantana@ufpe.br) on 2017-12-06T17:09:43Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) tese deposito Eduardo Dias.pdf: 13485018 bytes, checksum: 3e7ed9b8bb164286f2486067e8bcc8c2 (MD5) / Made available in DSpace on 2017-12-06T17:09:43Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) tese deposito Eduardo Dias.pdf: 13485018 bytes, checksum: 3e7ed9b8bb164286f2486067e8bcc8c2 (MD5) Previous issue date: 2015-03-03 / A investigação que esta pesquisa empreende procurou desenvolver uma perspectiva para a compreensão dos julgamentos de valor de autoria do videoclipe e as atribuições que decorrem desse processo, observando como as transformações na materialidade do videoclipe estão articuladas a mudanças na própria ideia de autoria, abordada nesta tese como autoria múltipla. A abrangência dessa discussão pretende incorporar as qualidades artísticas dos clipes articulando-as com as suas características promocionais e midiáticas, desenvolvendo um resgate das principais perspectivas sobre a autoria nas indústrias culturais com o intuito de instrumentalizar uma noção que priorize esta natureza ambígua do videoclipe. O intuito é amplificar o panorama da discussão sobre autoria no videoclipe desenvolvido a partir das suas próprias particularidades como um formato cultural. Esse panorama foi construído a partir de discussões sobre as características de produção e reconhecimento do clipe que despertaram as atribuições e manifestações de autoria ao longo de sua história. A proposta se concretizou através da promoção de uma perspectiva da valoração autoral no videoclipe cuja abrangência atinja os modos de produção e consumo juntamente com a percepção das ações dos indivíduos envolvidos na criação, produção e reconhecimento. Assim, hoje, para além da perspectiva dos videoclipes como um formato ligado às grades televisivas, é importante pensá-los em suas formas de autoria múltipla como ambientes visuais que acionam valorações e atribuições de autoria aos clipes. / This research seeks to develop a perspective to the comprehension of value judgments of authorship and their assignments, noticing the transformations in how the materialization of music vídeo are articulated to the change in the ideia of authorship, addressed in this research as multiple authorship. This discussion coverage intend embody the artistic qualities of music vídeos in an articulation with their marketing and media characteristics with the assistence of the majors perspectives about authorship in the cultural industry to promote an view which honors the ambiguous essence of music videos. The intention is amplify the survey of discussion about authorship in music video developed on their own features as cultural format. This survey was built from discussions about features of production and consumption of music vídeo which arouse the attributions and manifestations of authorship in their own history. The proposition was materialized through the production of a perspective of authorship valuation in music vídeo whick coverage reachs the forms of production and comsumption along with perception of individuals’ attitudes who are attendants in the conception, production and consumption. Thus, beyond the production television-centered, it is important considering forms of multiple authorship as visuals ambients which operates valuations and attributions of authorship in music video.

This research has developed a novel method which uses an easy to deploy single dry electrode wireless electroencephalogram (EEG) collection device as an input to an automated system that measures indicators of a participant’s attentiveness while they are watching a short training video. The results are promising, including 85% or better accuracy in identifying whether a participant is watching a segment of video from a boring scene or lecture, versus a segment of video from an attentiveness inducing active lesson or memory quiz. In addition, the final system produces an ensemble average of attentiveness across many participants, pinpointing areas in the training videos that induce peak attentiveness. Qualitative analysis of the results of this research is also very promising. The system produces attentiveness graphs for individual participants and these triangulate well with the thoughts and feelings those participants had during different parts of the videos, as described in their own words. As distance learning and computer based training become more popular, it is of great interest to measure if students are attentive to recorded lessons and short training videos. This research was motivated by this interest, as well as recent advances in electronic and computer engineering’s use of biometric signal analysis for the detection of affective (emotional) response. Signal processing of EEG has proven useful in measuring alertness, emotional state, and even towards very specific applications such as whether or not participants will recall television commercials days after they have seen them. This research extended these advances by creating an automated system which measures attentiveness towards short training videos. The bulk of the research was focused on electrical and computer engineering, specifically the optimization of signal processing algorithms for this particular application. A review of existing methods of EEG signal processing and feature extraction methods shows that there is a common subdivision of the steps that are used in different EEG applications. These steps include hardware sensing filtering and digitizing, noise removal, chopping the continuous EEG data into windows for processing, normalization, transformation to extract frequency or scale information, treatment of phase or shift information, and additional post-transformation noise reduction techniques. A large degree of variation exists in most of these steps within the currently documented state of the art. This research connected these varied methods into a single holistic model that allows for comparison and selection of optimal algorithms for this application. The research described herein provided for such a structured and orderly comparison of individual signal analysis and feature extraction methods. This study created a concise algorithmic approach in examining all the aforementioned steps. In doing so, the study provided the framework for a systematic approach which followed a rigorous participant cross validation so that options could be tested, compared and optimized. Novel signal analysis methods were also developed, using new techniques to choose parameters, which greatly improved performance. The research also utilizes machine learning to automatically categorize extracted features into measures of attentiveness. The research improved existing machine learning with novel methods, including a method of using per-participant baselines with kNN machine learning. This provided an optimal solution to extend current EEG signal analysis methods that were used in other applications, and refined them for use in the measurement of attentiveness towards short training videos. These algorithms are proven to be best via selection of optimal signal analysis and optimal machine learning steps identified through both n-fold and participant cross validation. The creation of this new system which uses signal processing of EEG for the detection of attentiveness towards short training videos has created a significant advance in the field of attentiveness measuring towards short training videos.

O presente trabalho tem, como objetivo, analisar o processo de sedimentação atual no Canal do Ararapira, Sistema Estuarino Lagunar de Cananéia-Iguape (SP), através das características composicionais e granulométricas dos sedimentos de fundo e distribuição da matéria orgânica sedimentar e carbonatos, relacionando estes parâmetros à configuração geral do canal e aos processos oceanográficos que ali atuam. Foram realizadas análises granulométricas, conteúdo de carbonato e matéria orgânica sedimentar (C, N, S) em 60 amostras de sedimentos coletadas em um cruzeiro oceanográfico realizado no mês de julho de 2004. Dentre o total de 60 amostras, foram selecionadas 16 para realização da análise da fração arenosa. A análise espacial da distribuição dos sedimentos e da matéria orgânica sedimentar, apontou para a predominância de sedimentos arenosos com baixos teores orgânicos ao longo de praticamente toda extensão do canal exceto em determinados pontos localizados no centro-norte do canal onde há presença de sedimentos finos associados a baixios e desembocaduras de gamboas e pequenos cursos d\'água continentais e insulares. Constatou-se a predominância da influência continental ao longo de todo o canal com pequenas concentrações de carbonatos. Os teores elementares da matéria orgânica sedimentar possuem, normalmente, comportamento e distribuição que estão diretamente relacionados aos tipos de sedimentos e à topografia de fundo, bem como à circulação. Observou-se uma relação direta entre os sedimentos mais finos e um maior conteúdo de matéria orgânica. / The aim of this study is the analysis of modern sedimentary process taking place in the Ararapira Channel, at Cananéia-Iguape lagoonal estuarine system (SP). The employed parameters for this were the composition and grain size characteristics of the bottom sediments , the distribution of the carbonates , organic matter, and relates these parameters to the general configuration of the channel and to the oceanographic process that takes place over there. The grain size analysis, the carbonate content, and the sediment organic matter (C, N, S) were conducted over 60 sediment samples collected during an oceanographic cruise that took place in July 2004. Among the total of the 60 samples, 16 were selected for the coarse fraction analysis. The spatial analysis of the distribution of sediments and sedimentary organic matter showed that sandy sediments, with low organic content, are predominant practically all along the whole of the channel extension, except in points located in the central-northern portion of the channel, where there are thin sediment associated to shoals or small continental and insular river courses. The C, N, S and carbonates contents observed with the coarse fraction analysis, allow identifying the predominance of continental influence all along the channel, with lower carbonate concentrations. The sediment organic matter contents have, usually, behavior and distribution which are directly related to the type of sediment ,to the bottom topography, as well as to the circulation. It was possible to observe a direct relationship between the thin sediment and a larger content of the organic matter.

O presente trabalho tem, como objetivo, analisar o processo de sedimentação atual no Canal do Ararapira, Sistema Estuarino Lagunar de Cananéia-Iguape (SP), através das características composicionais e granulométricas dos sedimentos de fundo e distribuição da matéria orgânica sedimentar e carbonatos, relacionando estes parâmetros à configuração geral do canal e aos processos oceanográficos que ali atuam. Foram realizadas análises granulométricas, conteúdo de carbonato e matéria orgânica sedimentar (C, N, S) em 60 amostras de sedimentos coletadas em um cruzeiro oceanográfico realizado no mês de julho de 2004. Dentre o total de 60 amostras, foram selecionadas 16 para realização da análise da fração arenosa. A análise espacial da distribuição dos sedimentos e da matéria orgânica sedimentar, apontou para a predominância de sedimentos arenosos com baixos teores orgânicos ao longo de praticamente toda extensão do canal exceto em determinados pontos localizados no centro-norte do canal onde há presença de sedimentos finos associados a baixios e desembocaduras de gamboas e pequenos cursos d\'água continentais e insulares. Constatou-se a predominância da influência continental ao longo de todo o canal com pequenas concentrações de carbonatos. Os teores elementares da matéria orgânica sedimentar possuem, normalmente, comportamento e distribuição que estão diretamente relacionados aos tipos de sedimentos e à topografia de fundo, bem como à circulação. Observou-se uma relação direta entre os sedimentos mais finos e um maior conteúdo de matéria orgânica. / The aim of this study is the analysis of modern sedimentary process taking place in the Ararapira Channel, at Cananéia-Iguape lagoonal estuarine system (SP). The employed parameters for this were the composition and grain size characteristics of the bottom sediments , the distribution of the carbonates , organic matter, and relates these parameters to the general configuration of the channel and to the oceanographic process that takes place over there. The grain size analysis, the carbonate content, and the sediment organic matter (C, N, S) were conducted over 60 sediment samples collected during an oceanographic cruise that took place in July 2004. Among the total of the 60 samples, 16 were selected for the coarse fraction analysis. The spatial analysis of the distribution of sediments and sedimentary organic matter showed that sandy sediments, with low organic content, are predominant practically all along the whole of the channel extension, except in points located in the central-northern portion of the channel, where there are thin sediment associated to shoals or small continental and insular river courses. The C, N, S and carbonates contents observed with the coarse fraction analysis, allow identifying the predominance of continental influence all along the channel, with lower carbonate concentrations. The sediment organic matter contents have, usually, behavior and distribution which are directly related to the type of sediment ,to the bottom topography, as well as to the circulation. It was possible to observe a direct relationship between the thin sediment and a larger content of the organic matter.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / A necessidade constante de serviÃos de manutenÃÃo e restauraÃÃo nas vias urbanas, agravadas pela falta de recursos disponÃveis para tal fim à o que motiva a implantaÃÃo dos sistemas de gerÃncia aplicada à pavimentaÃÃo urbana. Estes sistemas sÃo capazes de alocar os recursos dos orÃamentos de manutenÃÃo de infra-estruturas de estradas, aos trechos mais necessitados, onde a sua utilizaÃÃo serà otimizada, priorizando-se os investimentos em funÃÃo do estado de conservaÃÃo da via e da importÃncia da mesma. Neste contexto, esta dissertaÃÃo propÃe a anÃlise dos defeitos existentes nos pavimentos urbanos atravÃs do uso da metodologia Paver (Pavement Maintenance Management System), desenvolvida pelo U.S. Army Corps of Engineers (USACE), baseada no cÃlculo do Ãndice de CondiÃÃo do Pavimento (PCI) que utiliza o tipo de defeito encontrado no pavimento e a sua severidade correspondente para calcular o seu valor. O estudo faz adaptaÃÃes à metodologia em questÃo para permitir a anÃlise de calÃamentos de paralelepÃpedos, bastante utilizados na cidade de Fortaleza, levantando os defeitos existentes nestes e avaliando a situaÃÃo dos mesmos pela Ãrea superficial dos danos existentes, uma vez que este tipo de revestimento nÃo à abordado pela metodologia Paver. Para testar a eficÃcia desta forma de anÃlise dos pavimentos urbanos, foi realizado um estudo de caso, em um trecho da malha viÃria urbana de Fortaleza, com 604m de extensÃo, que apresenta um trecho asfaltado e outro calÃado com paralelepÃpedos. Os resultados demonstraram a facilidade de aplicaÃÃo da metodologia e da adaptaÃÃo desenvolvida, propiciando a viabilidade de sua implantaÃÃo na malha viÃria urbana das grandes cidades em um Sistema de GerÃncia de Pavimentos (SGP). AtravÃs dos critÃrios de priorizaÃÃo, expostos no Paver, pode-se fornecer uma lista de prioridades de intervenÃÃo nos segmentos de uma malha viÃria, que necessitam de intervenÃÃo, reduzindo deste modo o desperdÃcio dos recursos pÃblicos e permitindo o controle destes nas obras de restauraÃÃo e manutenÃÃo das vias. / The necessity of constant maintenance and restoration services of the urban ways, aggravated by the lack of proper and sufficient resources, is the main motive for the application of management systems on urban pavements. These systems make it possible to allocate resources of the road infrastructure maintenance budget to the areas where they are most needed. By doing this, it becomes possible to optimize investments using them according to certain criteria, which will take into consideration the waysâ conservation status and also their importance. Within this context, this dissertation proposes an analysis of the existing distresses on urban pavements through the use of the PAVER methodology (Pavement Maintenance Management System), which was developed by the U.S. Army Corps of Engineers (USACE). Such methodology is based on the Pavement Condition Index (PCI), which takes into consideration the type of distress found and its severity level to calculate its value. In order to permit an analysis of ways with paving stone surfaces, which is frequently seen in Fortaleza, there have been some adaptations on the studied methodology by listing the existing distresses and evaluating their situation for the existing damagesâ superficial area, once that this type of way is not approached by the PAVER methodology. In order to test the efficiency of this way of analyzing urban pavements, a case-study has been conducted in a small portion, 604 meters long, of Fortalezaâs road network which is composed by two different paving surfaces; asphalt and paving stone. The results show the applicability of this methodology and the adaptation that has been developed, making it possible its implementation in big citiesâ road networks in a Pavement Management System (PMS). Through the criteria of priorities, postulated by PAVER, one can provide a list of priorities of intervention in road network segments, the ones that really need intervention, as to reduce the waste of public resources and allow a better spending control of these resources when restoration and maintenance services are being carried out in road networks.

Recently the role of marketing strategy for a company has significantly increased. Marketing strategy -- as a main plan which not only includes product, promotion, distribution, and pricing approach, but also determines the choice of market segment, positioning, and allocation of resources -- has become vital for a company. The main goal of the thesis will be to analyze and assess presently used marketing strategy of Philips Lighting in the Czech Republic in business to business market. Therefore, analyses that should be conducted before formulating a marketing strategy will be clarified. Since a wide variety of approaches to the categorization of marketing strategy exists, it will not be the goal of the author to deliver a complete enumeration of marketing strategies. With regards to the subject, classification reflecting company's position in the market, product life cycle period and market situation will be explained. Consequently, having acquired knowledge of marketing strategy categorization, and based mainly on the SWOT and Porter's industry analysis, recommendations and correcting measurements of Philips Lighting marketing strategy will be suggested.

A estimação da estrutura da taxa de juros é relevante por duas razões fundamentais: em primeiro lugar é considerado como um indicador antecipado de política, sendo uma das principais ferramentas para os bancos centrais como instrumento de política monetária; em segundo lugar, através da curva de rendimentos é possível fazer valoração de ativos financeiros. A causa da sua relevância, tanto na área macroeconômica e como no campo financeiro, uma ampla literatura dedicada a estimá-la se desenvolveu. Neste sentido, o objetivo deste documento é a previsão da curva de rendimentos da Colômbia através da metodologia de Spectrum Singular Analysis (SSA) durante o período 2006-2014. Para a previsão são usados parâmetros diários estimados pelo modelo de fatores de Nelson e Siegel (1987). Os resultados indicam ganhos na acurácia preditiva fora da amostra da abordagem de MSSA em relação ao modelo Random Walk e outros benchmarks amplamente usados na literatura, principalmente nos horizontes de previsão mais curtos. Os resultados são estatisticamente significantes. Assim mesmo, observasse que o MSSA se ajusta melhor que os modelos competidores em todos os horizontes para as previsões das menores maturidades. / The estimation of the Yield curve is relevant because of two fundamental reasons: firstly, it is considered an anticipated indicator of economic policies, being one of the principal central banks tools as instrument of monetary policy; secondly, through this estimation it is possible to valuate financial assets. Due to its relevance in the macroeconomics area and the financial field, an extensive literature has been dedicated to its estimation. Concerning that, the goal of this document is to get a prediction of Colombia’s yield curve through the Spectrum Singular Analysis (SSA) from 2006 to 2014. Daily estimated parameters by Nelson and Siegel (1987) factors model are used to obtain the prognostication. Results are statistically significant and indicate gains of the MMSA on the accuracy of previsions out of the sample in relation to the Random Walk competitor model and other benchmarks widely used in literature, mainly on short term previsions. Likewise, we observe that the MSSA method is better adjusted than competitors’ models in all the horizons for the previsions where maturity is lower. / La estimación de la curva de rendimientos es relevante por dos razones fundamentales: en primer lugar es considerado como un indicador anticipado de política económica, siendo una de las principales herramientas para los bancos centrales como instrumento de política monetaria; en segundo lugar, a través de esta es posible realizar valoración de activos financieros. Dada su relevancia tanto en el área macroeconómica como en el campo financiero una amplia literatura ha sido dedicada a su estimación. En este sentido, el objetivo de este documento es la previsión de la curva de rendimientos de Colombia a través de la metodología de Spectrum Singular Analysis (SSA) durante noviembre de 2006 a diciembre de 2014. Para su pronóstico son usados los parámetros diarios estimados por el modelo de factores de Nelson e Siegel (1987). Los resultados son estadísticamente significativos e indican ganancias del método MSSA en la precisión de las previsiones fuera de la muestra principalmente en horizontes de previsión más cortos en relación al Random Walk y otros benchmarks ampliamente usados en la literatura. Así mismo, se observa que el método MSSA se ajusta mejor que los modelos competidores en todos los horizontes para las previsiones donde el vencimiento es menor.

Στην παρούσα διπλωματική εργασία μελετάμε την κλασική δυναμική ατόμου υδρογόνου σε γενικευμένο δυναμικό Van der Waals. Το πρόβλημα ανήκει στην ευρύτερη κατηγορία των μη γραμμικών Χαμιλτώνιων δυναμικών συστημάτων. Σκοπός της μελέτης είναι η ανάλυση των ιδιομορφιών της κανονικής και χαοτικής κίνησης του συστήματος στο μιγαδικό πεδίο του χρόνου και η εξαγωγή συμπερασμάτων σχετικά με την ολοκληρωσιμότητα και επιλυσιμότητά του. Εκείνο που θέλουμε να κατανοήσουμε, επίσης, είναι τον ρόλο που παίζει η εμφάνιση ιδιομορφιών σε κάποια σημεία του χώρου των φάσεων και κατά πόσο μπορούν αυτές να επηρεάσουν συνολικά τις ιδιότητες των λύσεων. Για πρώτη φορά, επίσης, στην διπλωματική αυτή εργασία εφαρμόζεται σε ένα Χαμιλτώνιο δυναμικό σύστημα μία νέα αριθμητική μέθοδος διάκρισης μεταξύ κανονικής και χαοτικής συμπεριφοράς σε διαφορετικές περιοχές του χώρου φάσεων, η μέθοδος των Μικρότερων Δεικτών Ευθυγράμμισης (Smaller Alignment Indices method ή SALI). Η μέθοδος αυτή έχει χρησιμοποιηθεί κατά το πρόσφατο παρελθόν σε απεικονίσεις δύο, τεσσάρων και έξι διαστάσεων με πολύ ενδιαφέροντα αποτελέσματα. Χαρακτηριστικά της είναι η αποτελεσματικότητα και η δυνατότητα εξαγωγής χρήσιμων συμπερασμάτων ως προς την κανονική και χαοτική φύση των τροχιών ενός δυναμικού συστήματος με μεγαλύτερη ταχύτητα και αξιοπιστία από την μέθοδο των χαρακτηριστικών εκθετών Lyapunov καθώς και άλλων νεότερων μεθόδων στην σύγχρονη βιβλιογραφία. Εδώ θα παρουσιασθεί η μέθοδος αυτή με ορισμένες βελτιώσεις ώστε να μπορεί να εφαρμοσθεί σε συστήματα μη γραμμικών διαφορικών εξισώσεων οποιασδήποτε διάστασης ελέγχοντας συστηματικά ένα όσο πυκνό πλέγμα αρχικών συνθηκών του χώρου φάσεων επιθυμούμε, αντιστοιχώντας σε κάθε μία από αυτές ένα χρώμα. Κάθε χρώμα αντιστοιχεί και σε ένα διαφορετικό εύρος τάξεων του SALI δημιουργώντας έτσι μία συνολική εικόνα στο χώρο φάσεων που μας επιτρέπει να γνωρίζουμε τη φύση της τροχιάς κάθε συγκεκριμένης αρχικής συνθήκης. Σχηματίζεται με αυτόν τον τρόπο το "μωσαϊκό" του χώρου φάσεων και αποκαλύπτονται περιοχές κανονικής κίνησης, χαοτικής κίνησης καθώς και νησίδες ή περιοχές στις οποίες δεν αντιστοιχεί καθόλου κίνηση. / In this master thesis we study the classical dynamics of hydrogen atoms in a generalized Van der Waals potential. The problem belongs to the class of non linear Hamiltonian systems. Our aim is the singularity analysis of the ordered and chaotic motion of the system in the complex plain of time and the extraction of valuable conclusions concerning its integrability and solvability. What we want to understand, also, is the role of the emergence of singularities in some points of the phase space of the aforementioned system and how the singularities can affect globally the properties of the solutions. For the first time, in this master thesis, we introduce and apply in a Hamiltonian system a new numerical method for the fast and efficient discrimination between ordered and chaotic motion in different parts of phase space, namely the method of the Smaller Alignment Index (SALI). The method has been introduced and applied recently in mappings of two, four and six dimensions with very satisfactory results. Its main characteristics are the effectiveness and the ability of extracting valuable conclusions about the ordered and chaotic nature of trajectories of a dynamical system faster than the traditional method of Lyapunov exponents as well as of other indices in the bibliography. We will introduce SALI with appropriate modifications that help using it in non linear systems of differential equations of arbitrary dimensions checking systematically a dense grid of initial conditions and corresponding in every orbit a different color. Every color corresponds to a different range of SALI values creating by that way a global picture of the phase space that allows us to know the dynamic nature of initial conditions. By that way, we construct a “mosaic” of the phase space and reveal parts of ordered motion as well as parts of chaotic motion and islands of stability.

A estimação da estrutura da taxa de juros é relevante por duas razões fundamentais: em primeiro lugar é considerado como um indicador antecipado de política, sendo uma das principais ferramentas para os bancos centrais como instrumento de política monetária; em segundo lugar, através da curva de rendimentos é possível fazer valoração de ativos financeiros. A causa da sua relevância, tanto na área macroeconômica e como no campo financeiro, uma ampla literatura dedicada a estimá-la se desenvolveu. Neste sentido, o objetivo deste documento é a previsão da curva de rendimentos da Colômbia através da metodologia de Spectrum Singular Analysis (SSA) durante o período 2006-2014. Para a previsão são usados parâmetros diários estimados pelo modelo de fatores de Nelson e Siegel (1987). Os resultados indicam ganhos na acurácia preditiva fora da amostra da abordagem de MSSA em relação ao modelo Random Walk e outros benchmarks amplamente usados na literatura, principalmente nos horizontes de previsão mais curtos. Os resultados são estatisticamente significantes. Assim mesmo, observasse que o MSSA se ajusta melhor que os modelos competidores em todos os horizontes para as previsões das menores maturidades. / The estimation of the Yield curve is relevant because of two fundamental reasons: firstly, it is considered an anticipated indicator of economic policies, being one of the principal central banks tools as instrument of monetary policy; secondly, through this estimation it is possible to valuate financial assets. Due to its relevance in the macroeconomics area and the financial field, an extensive literature has been dedicated to its estimation. Concerning that, the goal of this document is to get a prediction of Colombia’s yield curve through the Spectrum Singular Analysis (SSA) from 2006 to 2014. Daily estimated parameters by Nelson and Siegel (1987) factors model are used to obtain the prognostication. Results are statistically significant and indicate gains of the MMSA on the accuracy of previsions out of the sample in relation to the Random Walk competitor model and other benchmarks widely used in literature, mainly on short term previsions. Likewise, we observe that the MSSA method is better adjusted than competitors’ models in all the horizons for the previsions where maturity is lower. / La estimación de la curva de rendimientos es relevante por dos razones fundamentales: en primer lugar es considerado como un indicador anticipado de política económica, siendo una de las principales herramientas para los bancos centrales como instrumento de política monetaria; en segundo lugar, a través de esta es posible realizar valoración de activos financieros. Dada su relevancia tanto en el área macroeconómica como en el campo financiero una amplia literatura ha sido dedicada a su estimación. En este sentido, el objetivo de este documento es la previsión de la curva de rendimientos de Colombia a través de la metodología de Spectrum Singular Analysis (SSA) durante noviembre de 2006 a diciembre de 2014. Para su pronóstico son usados los parámetros diarios estimados por el modelo de factores de Nelson e Siegel (1987). Los resultados son estadísticamente significativos e indican ganancias del método MSSA en la precisión de las previsiones fuera de la muestra principalmente en horizontes de previsión más cortos en relación al Random Walk y otros benchmarks ampliamente usados en la literatura. Así mismo, se observa que el método MSSA se ajusta mejor que los modelos competidores en todos los horizontes para las previsiones donde el vencimiento es menor.