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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.
21

Δυναμική χαμηλοδιάστατων τόρων και χάος σε χαμιλτώνια συστήματα πολλών βαθμών ελευθερίας

Χριστοδουλίδη, Ελένη 07 June 2010 (has links)
Η παρούσα εργασία αφορά στη μελέτη Χαμιλτώνιων συστημάτων Ν μη γραμμικών ταλαντωτών, όπως είναι αυτό των Fermi Pasta και Ulam (FPU), με στόχο την βαθύτερη κατανόηση της δυναμικής των σχεδόν-περιοδικών τροχιών και του ρόλου των αντίστοιχων τόρων στο χώρο φάσεων, καθώς αυξάνουμε την ενέργεια Ε και τον αριθμό βαθμών ελευθερίας Ν του συστήματος. Το βασικό μας αποτέλεσμα είναι ότι υπάρχουν τόροι χαμηλής διάστασης, που προκύπτουν από τη συνέχεια των αντίστοιχων του γραμμικού συστήματος, οι οποίοι ευθύνονται για τις FPU επαναλήψεις και εμποδίζουν την ισοκατανομή της ενέργειας μεταξύ όλων των κανονικών τρόπων ταλάντωσης. Αναλύοντας ευστάθεια αυτών των τόρων, μπορέσαμε να δώσουμε μια πληρέστερη ερμηνεία στο Παράδοξο των FPU, συνδέοντας και συμπληρώνοντας έτσι δύο από τις επικρατέστερες ερμηνείες του εν λόγω φαινομένου. / The present work concerns the study of Hamiltonian systems of N nonlinear coupled oscillators, as it is the one by Fermi Pasta and Ulam (FPU), in order to understand the dynamics of quasi-periodic orbits and the role of their corresponding tori in phase space, as we increase the energy E and the number N of the degrees of freedom. Our fundamental result is that there exist tori of low dimension, that come from the continuation of the corresponding tori of the linear system, which are responsible for the FPU recurrences and prevent the system from equipartition of the energy among all normal modes. By investigating the stability of these tori, we achieved to provide a more complete explanation for the FPU paradox, connecting and supplementing in this way two of the most dominant approaches for this paradox.
22

Résistance à la cavitation : des mécanismes physiologiques à la génétique évolutive : de la bulle aux gènes / Resistance to cavitation : from physiological mechanisms to evolutionary quantitative genetic : from the bubble to genes

Lamy, Jean-Baptiste 13 March 2012 (has links)
Force est de constater que les dépérissements forestiers augmentent. Ces observations vont de pairs avec l’accroissement des événements climatiques extrêmes. Aussi dans ce contexte, il est nécessaire d’identifier denouveaux caractères de resistance à la sécheresse. La résistance à la cavitation est actuellement le meilleurmarqueur de la survie d’une espèce à la sécheresse.Cette thèse avait deux objectifs : (i) comprendre le mécanisme de propagation de la cavitation dans le xylèmechez les gymnospermes. (ii) Quantifier la variation phénotypique in situ de ce caractère chez Pinus pinaster ainsique (iii) quantifier la variation génétique, et sa plasticité phénotypique.La démarché a été la suivante (i) une étude interspécifique de la résistance à la cavitation a été couplé à desmesures micro-anatomiques. (ii) Pour le volet intraspécifique, nous avons phénotypé 6 populations dans deuxtest de populations-descendances, ainsi qu’en population naturelles in situ.La propagation de l’embolie chez les Pinaceae et les ex-Taxodiaceae pourrait être due au passage du germe d’air(rupture capillaire) à travers des nanopores dans le torus. En effet, la pression de rupture d’un ménisque air-sèveest corrélée à l’entrée de l’air dans le xylème (P12). Alors que la variation interspécifique est grande, la résistanceà la cavitation varie faiblement au sein d’une espèce. Ainsi les populations provenant de climat contrasté neprésentent pas ou peu de différence génétique (en test de provenance) ou en populations naturelles in situ. Cecaractère présente une plasticité phénotypique mais faible comparée à celle de la croissance en hauteur parexemple. La comparaison entre la variation génétique entre populations et la variation des marqueurs neutresentre ces mêmes populations montrent que la variation de ce caractère semble réduite par l’architecturegénétique sous-jacente. La resistance à la cavitation est vraisemblablement un trait canalisé. / Several review reported global forest die-back that are caused, directly or indirectly, by extreme climatic events(like heat waves or prolonged drought). In this context, there is an urgent need to identify new traits to tracedrought tolerance. Resistance to cavitation is one of the best proxy for survival during extreme drought.The aim of this work was (i) to understand how spreads cavitation in the vascular pathway of gymnosperms (ii)to quantify the phenotypic variation of resistance to cavitation for Pinus pinaster species, (iii) to determine theamount of the genetic variation and phenotypic plasticity available for this trait.A micro-anatomy study was coupled to measurement of resistance to cavitation for various species to foundwhere air-seeding occurs in the bordered pit. To quantify the variability of resistance to cavitation, wephenotyped 506 genotypes using to replicated provenance-progeny trials and on natural in situ populations.The spread of embolism for Pinaceae and ex-Taxodiaceae could be due to minute pore in tori, which are remainsof secondary plasmodesmata. We found that the pressure needed to break a water/air meniscus in these minutepores is correlated with the xylem air entry (P12). Despite the great variability of resistance to cavitation betweenspecies, we found low variability within species. Most of the variability is within population, rather than betweenpopulations. The phenotypic plasticity of resistance to cavitation is low compare to growth traits. Comparisonbetween QST and FST shows that populations exhibit less variation compare to what it is expected under geneticdrift. The variation of resistance to cavitation seems to be narrowed by the genetic architecture, which is the signof canalisation.
23

從聯合國海洋法公約第121條論日本延伸大陸礁層外部界限提案內容之合法性 / The legitimacy of the Japan’s submission on the outer limits of the continental shelf - An analysis from the Article 121 of the United Nations Convention on the Law of the Sea

陳杏莉 Unknown Date (has links)
2001年5月29日第11次《聯合國海洋法公約》締約國會議通過SPLOS/72號決定,於1999年5月13日以前對其生效之公約締約國,如欲依《聯合國海洋法公約》第76條規定主張200海里以外之大陸礁層,必須在1999年5月13日起算10年內向聯合國大陸礁層界限委員會提交與其所主張大陸礁層外部界限相關科學及技術佐證資料。由於《聯合國海洋法公約》所定義之大陸礁層外部界限範圍可能超越專屬經濟海域範圍,而大陸礁層不僅是魚類資源較豐富也是漁業活動重要資源地,同時也是海底油氣與礦場等重要自然資源的集中地區。因此,包括我國相鄰之日本、菲律賓、越南、馬來西亞等公約締約國紛紛進行大陸礁層調查來擴展自己國家的海洋權益。至2009年12月止,已有51個延伸大陸礁層外部界限之提案,及44個初步資訊,聯合國大陸礁層界限委員會並已就部分提案作成決議。 日本於2008年11月12日向聯合國大陸礁層界限委員會提出該國延伸大陸礁層外部界限之申請,卻也因此引起中國大陸及韓國對日本提案中以「沖之鳥礁」為基礎劃定超出200海里延伸大陸礁層之主張提出反對意見,質疑「沖之鳥礁」之法律地位及其所能享有的海域管轄空間。本論文爰由《聯合國海洋法公約》第121條「島嶼制度」形成的過程、相關國家實踐及學者見解,以及《聯合國海洋法公約》中「大陸礁層」之相關規範及聯合國大陸礁層界限委員會之組織與運作情形,探討日本的延伸大陸礁層外部界限提案中以「沖之鳥礁」為基礎主張延伸大陸礁層之適法性問題,並分析以聯合國大陸礁層界限委員會作為「沖之鳥礁」法律地位爭端解決途徑之可能性等。研究結果顯示,日本提案以「沖之鳥礁」為基礎主張延伸大陸礁層外部界限不符合《聯合國海洋法公約》第121條第3項規定,但該項規定並未具備有習慣國際法的效力,亦缺乏客觀的認定標準,聯合國大陸礁層界限委員會的場域無法解決「沖之鳥礁」的法律地位爭端,其他沿海國僅能利用聯合國大陸礁層界限委員會中「第三國意見」之機制凸顯爭端的存在,提醒國際社會注意此類島礁的海域管轄空間主張的合理性問題,並應尊重公約所賦予的權利與義務。 / On 29 May 2001, the 11th Meeting of States Parties to the United Nations Convention on the Law of the Sea (UNCLOS) adopted the SPLOS/72 Decision regarding the date of commencement of the ten-year period for making submissions to the Commission on the Limits of the Continental Shelf set out in Article 4 of Annex II to the UNCLOS. It was decided that, in the case of a State Party for which the Convention entered into force before 13 May 1999, the ten-year time period for it to submit the scientific and technical data supporting the outer limits of its continental shelf beyond 200 nautical miles under Article 76 of the UNCLOS shall be taken to have commenced on 13 May 1999. For quite a few States the outer limits of their continental shelf as defined by the UNCLOS may go beyond the limits of the Exclusive Economic Zone (EEZ). Besides, continental shelf is abundant in fisheries resources, crude oil, natural gas and minerals. Consequently, the neighboring States of Taiwan, including Japan, the Philippines, Viet Nam, and Malaysia, have already begun their surveys on continental shelf in order to expand their interests hidden in the ocean. As of December of 2009, there have been 51 formal submissions and 44 Preliminary Information delivered to the United Nations. The Commission on the Limits of the Continental Shelf (CLCS) has been undertaking the consideration of these submissions and already completed such process for some of them with recommendations. For Japan, the submission to support the outer limits of its extended continental shelf was made on 12 November 2008 to the CLCS. Such submission was challenged by China and Korea whose focus is on the part of extended continental shelf generated by Oki-no-tori Shima. The legal status of Oki-no-tori Shima as being capable of generating EEZ, continental shelf, and extended continental shelf beyond 200 nautical miles, is being disputed by the communications from China and Korea. To provide educated comments on such controversy, this thesis will discuss the legislative process of Article 121 of the UNCLOS, namely, the regime of islands. Related state practices and teachings of the most highly qualified publicists will be studied in this connection. The author will also examine the regime of continental shelf under the UNCLOS and the institution of the CLCS. These will pave the way to scrutinize the legality of using Oki-no-tori Shima as the basis to generate extended continental shelf as having been done by Japan in its submission. The author will also explore the feasibility for the CLCS to settle the dispute over the legality of Japanese submission with respect to Oki-no-tori Shima. As shown by research works, the Japanese submission using Oki-no-tori Shima to generate extended continental shelf is inconsistent with Article 121(3) of the UNCLOS. However, the rule as contained in Article 121(3) has not yet been received into customary international law. Also lacking are the objective criteria to decide whether a given rock meets the conditions as stipulated by Article 121(3) or not. The forum of the CLCS is not suitable to settle the dispute over the legality of using Oki-no-tori Shima by Japan to generate extended continental shelf. Other coastal States can only use the forum of the CLCS to demonstrate the legal controversy over this case through sending third party communications to notify the CLCS the existence of dispute and their unwillingness to support the CLCS to consider the Japanese submission with respect to the part of Oki-no-tori Shima. As submitted by this author, the international community should be reminded of the necessity to respect the integrity of the rights and duties enshrined by the UNCLOS. Also worthy of careful scrutiny is the legitimacy of such kinds of exaggerated maritime claims generated by the rock as defined by Article 121(3) of the UNCLOS.
24

Espaces de Hardy en probabilités et analyse harmonique quantiques / Hardy spaces in probability and quantum harmonic analysis

Yin, Zhi 07 June 2012 (has links)
Cette thèse présente quelques résultats de la théorie des probabilités quantiques et de l’analyse harmonique à valeurs operateurs. La thèse est composée des trois parties.Dans la première partie, on démontre la décomposition atomique des espaces de Hardy de martingales non commutatives. On identifie aussi les interpolés complexes et réels entre les versions conditionnelles des espaces de Hardy et BMO de martingales non commutatives.La seconde partie est consacrée à l’étude des espaces de Hardy à valeurs opérateursvia la méthode d’ondellettes. Cette approche est similaire à celle du cas des martingales non commutatives. On démontre que ces espaces de Hardy sont équivalents à ceux étudiés par Tao Mei. Par conséquent, on donne une base explicite complètement inconditionnelle pour l’espace de Hardy H1(R), muni d’une structure d’espace d’opérateurs naturelle. La troisième partie porte sur l’analyse harmonique sur le tore quantique. On établit les inégalités maximales pour diverses moyennes de sommation des séries de Fourier définies sur le tore quantique et obtient les théorèmes de convergence ponctuelle correspondant. En particulier, on obtient un analogue non commutative du théorème classique de Stein sur les moyennes de Bochner-Riesz. Ensuite, on démontre que les multiplicateurs de Fourier complètement bornés sur le tore quantique coïncident à ceux définis sur le tore classique. Finalement, on présente la théorie des espaces de Hardy et montre que ces espaces possèdent les propriétés des espaces de Hardy usuels. En particulier, on établit la dualité entre H1 et BMO. / This thesis presents some results in quantum probability and operator-valued harmonicanalysis. The main results obtained in the thesis are contained in the following three parts:In first part, we prove the atomic decomposition for the Hardy spaces h1 and H1 of noncommutative martingales. We also establish that interpolation results on the conditionedHardy spaces of noncommutative martingales. The second part is devoted to studying operator-valued Hardy spaces via Meyer’s wavelet method. It turns out that this way of approaching these spaces is parallel to that in the noncommutative martingale case. We also show that these Hardy spaces coincide with those introduced and studied by Tao Mei in [52]. As a consequence, we give an explicit completely unconditional base for Hardy spaces H1(R) equipped with a natural operator space structure. The third part deals with with harmonic analysis on quantum tori. We first establish the maximal inequalities for several means of Fourier series defined on quantum tori and obtain the corresponding pointwise convergence theorems. In particular, we prove the noncommutative analogue of the classical Stein theorem on Bochner-Riesz means. Then we prove that Lp completely bounded Fourier multipliers on quantum tori coincide with those on classical tori with equal cb-norms. Finally, we present the H1-BMO and Littlewood- Paley theories associated with the circular Poisson semigroup over quantum tori.
25

Automated flow systems for total and isotopic analysis of thorium and uranium in samples of environmental interest

Avivar Cerezo, Jessica 16 March 2012 (has links)
Tenint en compte, les característiques i la presència d’urani i tori al medi ambient, així com la evolució de les directives que estipulen els nivells màxims de materials radioactius al medi ambient, en aquesta tesis es presenten dues revisions exhaustives i quatre mètodes analítics per a la determinació total e isotòpica de tori i urani, com alternatives a les separacions radioquímiques clàssiques, que es caracteritzen per ser laborioses i de llarga duració. Aquestes metodologies varen ser automatitzades mitjançant l’ús de tècniques d’anàlisis en flux multiconmutades, les quals proporcionen un important estalvi de reactius, amb la conseqüent reducció de cost per anàlisis i de generació de residus permetent una major freqüència d’anàlisis, i una mínima manipulació de les mostres. La espectrofotometria de llarg pas òptic i la espectrometria de masses de plasma acoblat inductivament (ICP-MS) varen ser les tècniques de detecció emprades en els mètodes desenvolupats com alternatives a detectors radiomètrics. / Taking into account the occurrence, the characteristics of uranium and thorium in the environment as well as the evolution of the directives which stipulate the limit values of radioactive materials in water samples, in this thesis two comprehensive reviews and four automated analytical systems for total and isotopic thorium and uranium determination are presented as alternatives to classical radiochemical separations which are laborious and time consuming. These methodologies have been automated exploiting multicommutated flow techniques, which provide minimal sample handling, low reagent consumption and waste generation and a high frequency of analysis. Long path length spectrophotometry and ICP-MS have been implemented in the developed methods as detection techniques instead of radiometric detectors in order to obtain fully automated, low cost and fast thorium and uranium analyzers. All the developed methods proposed in this thesis have been satisfactorily applied to environmental samples and have been validated with reference materials
26

Určení pozice kamery v reálném čase pro rozšířenou realitou / Real-time camera pose estimation for augmented reality

Szentandrási, István Unknown Date (has links)
Definované markery tvoří základ určování polohy kamery pro velké množství aplikací s rozšířenou realitou, v případě že jsou přísné požadavky na rychlost a robustnost. Tato práce popisuje účinnou metodu pro určení pózy kamery pomocí Uniformního pole markerů a několik realistických aplikací na bázi popsané metody. Metoda je velice výpočetně levná a poskytuje spolehlivou detekci pro několik výpočetních platforem, včetně běžných chytrých telefonů. Markery jako část zobrazené informace na monitorech jsou použité v této práci pro určení relativní orientaci mezi poskytovatelem obsahu a užívatelským zařízením, sloužícím pro výběr prvků užívatelského rozhraní při  interakci a migraci úkolů. Ve filmařském průmyslu poskytuje popsaná metoda pro zjištění polohy kamery jako součást klíčovaní pozadí filmářům živý náhled virtuální scény. Výsledky ukazují, že popsaná metoda pro detekci pole markerů má srovnatelnou úspěšnost a přesnost v porovnání s ostatními metodami na bázi markerů a je několikrát rýchlejší. Aplikace zahrnuté v této práci podle výsledků testů jsou životaschopné - rychlejší a levnější - alternativy k existujícím řešením.
27

Way of the Butterfly: A Journey towards Transformation through Self-portraits In-Between

Koshikawa, Masami 01 January 2015 (has links)
It has not been easy for me to talk about myself or describe my feelings or thoughts. Coming from Japan, a collective society, we typically are not raised to do so. Throughout the MFA program at UCF, I have shared my feelings and thoughts through my work. It is important to discuss and inform others of our cultural similarities and differences so that we may gain a better understanding of each other. This process has helped me grow not only on an artistic level, but also on a personal level. My journey towards integration has led me to a meaningful studio practice, which has allowed my work to bridge the gap between Western and Eastern artistic sensibilities. At the beginning of the MFA program, my mother sent many boxes of origami from Japan. As I started incorporating my mother’s origami into my work, I found myself identifying with the origami butterfly. My realization is that the person I am now is not the person I was when I began this journey. My wish for you, the reader, is to go along with me as I tell you the story of my transformation.
28

Characterization of Quasi-Periodic Orbits for Applications in the Sun-Earth and Earth-Moon Systems

Brian P. McCarthy (5930747) 17 January 2019 (has links)
<div>As destinations of missions in both human and robotic spaceflight become more exotic, a foundational understanding the dynamical structures in the gravitational environments enable more informed mission trajectory designs. One particular type of structure, quasi-periodic orbits, are examined in this investigation. Specifically, efficient computation of quasi-periodic orbits and leveraging quasi-periodic orbits as trajectory design alternatives in the Earth-Moon and Sun-Earth systems. First, periodic orbits and their associated center manifold are discussed to provide the background for the existence of quasi-periodic motion on n-dimensional invariant tori, where n corresponds to the number of fundamental frequencies that define the motion. Single and multiple shooting differential corrections strategies are summarized to compute families 2-dimensional tori in the Circular Restricted Three-Body Problem (CR3BP) using a stroboscopic mapping technique, originally developed by Howell and Olikara. Three types of quasi-periodic orbit families are presented: constant energy, constant frequency ratio, and constant mapping time families. Stability of quasi-periodic orbits is summarized and characterized with a single stability index quantity. For unstable quasi-periodic orbits, hyperbolic manifolds are computed from the differential of a discretized invariant curve. The use of quasi-periodic orbits is also demonstrated for destination orbits and transfer trajectories. Quasi-DROs are examined in the CR3BP and the Sun-Earth-Moon ephemeris model to achieve constant line of sight with Earth and avoid lunar eclipsing by exploiting orbital resonance. Arcs from quasi-periodic orbits are leveraged to provide an initial guess for transfer trajectory design between a planar Lyapunov orbit and an unstable halo orbit in the Earth-Moon system. Additionally, quasi-periodic trajectory arcs are exploited for transfer trajectory initial guesses between nearly stable periodic orbits in the Earth-Moon system. Lastly, stable hyperbolic manifolds from a Sun-Earth L<sub>1</sub> quasi-vertical orbit are employed to design maneuver-free transfer from the LEO vicinity to a quasi-vertical orbit.</div>

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