O grande desafio da Implantodontia é alcançar resultados a longo prazo com maior preservação dos tecidos ósseos, resposta adequada dos tecidos conjuntivos e manutenção da estabilidade secundária adequada para a retenção de próteses. Estes fatores evitam a perda indesejável tanto do tratamento reabilitador quanto dos tecidos ósseos de suporte. A região extraoral apresenta menores espessuras ósseas em comparação às regiões de maxila e mandíbula, especialmente no osso temporal. Portanto, os seguintes aspectos foram investigados: (i) Análise pelo Método dos Elementos Finitos (FEA) de 16 modelos virtuais, com aplicação de forças estáticas de tensão e compressão nos pontos médios entre os implantes. Três implantes maxilofaciais extraorais foram posicionados no osso temporal, onde um deles foi posicionado sobre o processo mastóide. Este estudo foi totalmente realizado em ambiente computacional. Foram empregados dois tipos de conexões protéticas e intermediários retos de conicidades 20º e 45º, posicionados virtualmente no modelo de osso temporal, com paralelismo entre eles. Foi desenhada uma barra virtual para retenção protética do tipo barra-clipe da prótese auricular. Foram consideradas as melhores configurações aquelas apresentando distribuição uniforme e branda das tensões de von Mises sobre o tecido ósseo adjacente aos implantes. (ii) Confecção de corpos de prova com graus variáveis de pigmentação para (a) melhorar a reprodutibilidade da coloração (b) entender e reduzir o processo de descoloração para melhorar a longevidade das próteses. Um elastômero maxilofacial tipo A foi pigmentado intrinsecamente de acordo com os seis tons da Escala de Fitzpatrick. Uma técnica de pigmentação foi desenvolvida a partir dos resultados obtidos a partir de uma Escala de Fitzpatrick impressa em papel e dos pigmentos intrínsecos de cores primárias. Este dimetil-metilvinil-siloxano reforçado por platina A 223-30 (Factor II, Inc., Lakeside, AZ, USA) apresenta dureza \"Shore-A\" 30. As amostras foram expostas a fotoenvelhecimento acelerado, e sua degradação mapeada com Espectroscopia UV/Vis/NIR. Concluiu-se que: (i) Os implantes com conexão cone Morse plataforma 3.7 tem melhor comportamento biomecânico com intermediários de 45o e altura de 2mm. Sugere-se planejamento cirúrgico visando a instalação a 3 horas para o temporal esquerdo e 9 horas para o temporal direito, mais 6 horas (mastóide). Implantes com conexão cone Morse plataforma 4.0 apresentaram comportamento biomecânico desejável com intermediários de 20o e alturas de 2mm or 4mm. Para implantes com conexão cone Morse plataforma 4.0, sugere-se a instalação a 6-9-12 horas para o temporal direito, e 12-6-3 para o esquerdo, visando comportamento biomecânico adequado. Sugere-se que os implantes extraorais Brånemark hexágono externo com plataforma 4.1 regular ou expandida sejam preferencialmente empregados com intermediários de 20o. (ii) O SiO2 5% pode ser adicionado à preparação do silicone para retardar o desbotamento da prótese maxilofacial. O TiO2 traz mudanças visuais significativas e pode ser considerado como opacificador. / Major challenges in Implantology include: achieving longevity of implants, bone tissue preservation, connective tissue suitable answer and maintenance of secondary stability in order to retain prosthesis. These factors avoid the undesirable loss of both rehabilitation treatment and supporting bone tissues. The extraoral region has less bone depth compared to the maxilla and mandible regions, especially for the temporal bone. Therefore, the following aspects were investigated: (i) Finite Elements Analysis (FEA) of 16 virtual models, with static application of tension and compression forces in medium points between implants. Three extraoral maxillofacial implants were placed on the temporal bone, which one of them was placed on the mastoid process. This study was made entirely in a computational environment. Two prosthetic connection types and straight Intermediários were employed, with conicities of 20º and 45º, placed virtually on the temporal bone model, mutually parallel. A virtual bar for bar-clip prosthetic retention of auricular prosthesis was designed. The best configurations were considered to be the ones presenting uniform and mild von Mises tension distribution over the bone tissue around the implants. (ii) Generation of samples with varying degree of pigmentation to (a) improve the reproducibility of the colouration (b) understand and minimise the discolouration process to improve prosthetics longevity. A maxillofacial elastomer type A was intrinsically pigmented according to the six tones of the Fitzpatrick Scale. A pigmentation technique was developed from spectroscopy outcomes of paper printed Fitzpatrick Scale and the primary colors pigments. This platinum reinforced dimethyl methylvinyl siloxane A 223-30 (Factor II, Inc., Lakeside, AZ, USA) presents \"Shore-A\" hardness 30. The samples were exposed to accelerated photo aging, and their degradation mapped with UV/Vis/NIR Spectroscopy. The effects of exclusion of oxygen and inclusion of nanoparticle fillers during prosthetic formulation were investigated. It was concluded that: (i) Morse taper prosthetic connection 3.7 platform implants, should be employed with 45o abutments with 2mm height. The surgical planning shall be for placement 3 hours for the left temporal bone and 9 hours for the right, and in 6 hours (mastoid). Morse taper prosthetic connection 4.0 platform implants behaved biomechanically desirably with 20o abutments in 2mm or 4mm heights. For the Morse taper connection 4.0 platform implants, their placement shall be in 6-9-12 hours, for the right temporal, and 12-3-6, for the left temporal, in order to achieve proper biomechanical behaviour. The Brånemark extraoral external hexagon implant, with 4.1 platform (normal or expanded) should preferrably be used with 20o abutments. (ii) The SiO2 5% may be added to the silicone preparation in order to slow maxillofacial prosthesis colour fading. The TiO2 brings visually significant changes and may be considered as an opacifier.

This thesis is primarily focused on problems in extremal combinatorics, although we will also consider some questions of analytic and algorithmic nature. The d-dimensional hypercube is the graph with vertex set {0,1}^d where two vertices are adjacent if they differ in exactly one coordinate. In Chapter 2 we obtain an upper bound on the 'saturation number' of Q_m in Q_d. Specifically, we show that for m ≥ 2 fixed and d large there exists a subgraph G of Q_d of bounded average degree such that G does not contain a copy of Q_m but, for every G' such that G ⊊ G' ⊆ Q_d, the graph G' contains a copy of Q_m. This result answers a question of Johnson and Pinto and is best possible up to a factor of O(m). In Chapter 3, we show that there exists ε > 0 such that for all k and for n sufficiently large there is a collection of at most 2^{(1-ε)k} subsets of [n] which does not contain a chain of length k+1 under inclusion and is maximal subject to this property. This disproves a conjecture of Gerbner, Keszegh, Lemons, Palmer, Pálvölgyi and Patkós. We also prove that there exists a constant c ∈ (0,1) such that the smallest such collection is of cardinality 2^{(1+o(1))^ck} for all k. In Chapter 4, we obtain an exact expression for the 'weak saturation number' of Q_m in Q_d. That is, we determine the minimum number of edges in a spanning subgraph G of Q_d such that the edges of E(Q_d)\E(G) can be added to G, one edge at a time, such that each new edge completes a copy of Q_m. This answers another question of Johnson and Pinto. We also obtain a more general result for the weak saturation of 'axis aligned' copies of a multidimensional grid in a larger grid. In the r-neighbour bootstrap process, one begins with a set A₀ of 'infected' vertices in a graph G and, at each step, a 'healthy' vertex becomes infected if it has at least r infected neighbours. If every vertex of G is eventually infected, then we say that A₀ percolates. In Chapter 5, we apply ideas from weak saturation to prove that, for fixed r ≥ 2, every percolating set in Q_d has cardinality at least (1+o(1))(d choose r-1)/r. This confirms a conjecture of Balogh and Bollobás and is asymptotically best possible. In addition, we determine the minimum cardinality exactly in the case r=3 (the minimum cardinality in the case r=2 was already known). In Chapter 6, we provide a framework for proving lower bounds on the number of comparable pairs in a subset S of a partially ordered set (poset) of prescribed size. We apply this framework to obtain an explicit bound of this type for the poset 𝒱(q,n) consisting of all subspaces of 𝔽_qⁿordered by inclusion which is best possible when S is not too large. In Chapter 7, we apply the result from Chapter 6 along with the recently developed 'container method,' to obtain an upper bound on the number of antichains in 𝒱(q,n) and a bound on the size of the largest antichain in a p-random subset of 𝒱(q,n) which holds with high probability for p in a certain range. In Chapter 8, we construct a 'finitely forcible graphon' W for which there exists a sequence (ε_i)^∞_i=1 tending to zero such that, for all i ≥ 1, every weak ε_i-regular partition of W has at least exp(ε_i^-2/2^{5log∗ε_i^-2}) parts. This result shows that the structure of a finitely forcible graphon can be much more complex than was anticipated in a paper of Lovász and Szegedy. For positive integers p,q with p/q ❘≥ 2, a circular (p,q)-colouring of a graph G is a mapping V(G) → ℤ_p such that any two adjacent vertices are mapped to elements of ℤ_p at distance at least q from one another. The reconfiguration problem for circular colourings asks, given two (p,q)-colourings f and g of G, is it possible to transform f into g by recolouring one vertex at a time so that every intermediate mapping is a p,q-colouring? In Chapter 9, we show that this question can be answered in polynomial time for 2 ≤ p/q < 4 and is PSPACE-complete for p/q ≥ 4.

O grande desafio da Implantodontia é alcançar resultados a longo prazo com maior preservação dos tecidos ósseos, resposta adequada dos tecidos conjuntivos e manutenção da estabilidade secundária adequada para a retenção de próteses. Estes fatores evitam a perda indesejável tanto do tratamento reabilitador quanto dos tecidos ósseos de suporte. A região extraoral apresenta menores espessuras ósseas em comparação às regiões de maxila e mandíbula, especialmente no osso temporal. Portanto, os seguintes aspectos foram investigados: (i) Análise pelo Método dos Elementos Finitos (FEA) de 16 modelos virtuais, com aplicação de forças estáticas de tensão e compressão nos pontos médios entre os implantes. Três implantes maxilofaciais extraorais foram posicionados no osso temporal, onde um deles foi posicionado sobre o processo mastóide. Este estudo foi totalmente realizado em ambiente computacional. Foram empregados dois tipos de conexões protéticas e intermediários retos de conicidades 20º e 45º, posicionados virtualmente no modelo de osso temporal, com paralelismo entre eles. Foi desenhada uma barra virtual para retenção protética do tipo barra-clipe da prótese auricular. Foram consideradas as melhores configurações aquelas apresentando distribuição uniforme e branda das tensões de von Mises sobre o tecido ósseo adjacente aos implantes. (ii) Confecção de corpos de prova com graus variáveis de pigmentação para (a) melhorar a reprodutibilidade da coloração (b) entender e reduzir o processo de descoloração para melhorar a longevidade das próteses. Um elastômero maxilofacial tipo A foi pigmentado intrinsecamente de acordo com os seis tons da Escala de Fitzpatrick. Uma técnica de pigmentação foi desenvolvida a partir dos resultados obtidos a partir de uma Escala de Fitzpatrick impressa em papel e dos pigmentos intrínsecos de cores primárias. Este dimetil-metilvinil-siloxano reforçado por platina A 223-30 (Factor II, Inc., Lakeside, AZ, USA) apresenta dureza \"Shore-A\" 30. As amostras foram expostas a fotoenvelhecimento acelerado, e sua degradação mapeada com Espectroscopia UV/Vis/NIR. Concluiu-se que: (i) Os implantes com conexão cone Morse plataforma 3.7 tem melhor comportamento biomecânico com intermediários de 45o e altura de 2mm. Sugere-se planejamento cirúrgico visando a instalação a 3 horas para o temporal esquerdo e 9 horas para o temporal direito, mais 6 horas (mastóide). Implantes com conexão cone Morse plataforma 4.0 apresentaram comportamento biomecânico desejável com intermediários de 20o e alturas de 2mm or 4mm. Para implantes com conexão cone Morse plataforma 4.0, sugere-se a instalação a 6-9-12 horas para o temporal direito, e 12-6-3 para o esquerdo, visando comportamento biomecânico adequado. Sugere-se que os implantes extraorais Brånemark hexágono externo com plataforma 4.1 regular ou expandida sejam preferencialmente empregados com intermediários de 20o. (ii) O SiO2 5% pode ser adicionado à preparação do silicone para retardar o desbotamento da prótese maxilofacial. O TiO2 traz mudanças visuais significativas e pode ser considerado como opacificador. / Major challenges in Implantology include: achieving longevity of implants, bone tissue preservation, connective tissue suitable answer and maintenance of secondary stability in order to retain prosthesis. These factors avoid the undesirable loss of both rehabilitation treatment and supporting bone tissues. The extraoral region has less bone depth compared to the maxilla and mandible regions, especially for the temporal bone. Therefore, the following aspects were investigated: (i) Finite Elements Analysis (FEA) of 16 virtual models, with static application of tension and compression forces in medium points between implants. Three extraoral maxillofacial implants were placed on the temporal bone, which one of them was placed on the mastoid process. This study was made entirely in a computational environment. Two prosthetic connection types and straight Intermediários were employed, with conicities of 20º and 45º, placed virtually on the temporal bone model, mutually parallel. A virtual bar for bar-clip prosthetic retention of auricular prosthesis was designed. The best configurations were considered to be the ones presenting uniform and mild von Mises tension distribution over the bone tissue around the implants. (ii) Generation of samples with varying degree of pigmentation to (a) improve the reproducibility of the colouration (b) understand and minimise the discolouration process to improve prosthetics longevity. A maxillofacial elastomer type A was intrinsically pigmented according to the six tones of the Fitzpatrick Scale. A pigmentation technique was developed from spectroscopy outcomes of paper printed Fitzpatrick Scale and the primary colors pigments. This platinum reinforced dimethyl methylvinyl siloxane A 223-30 (Factor II, Inc., Lakeside, AZ, USA) presents \"Shore-A\" hardness 30. The samples were exposed to accelerated photo aging, and their degradation mapped with UV/Vis/NIR Spectroscopy. The effects of exclusion of oxygen and inclusion of nanoparticle fillers during prosthetic formulation were investigated. It was concluded that: (i) Morse taper prosthetic connection 3.7 platform implants, should be employed with 45o abutments with 2mm height. The surgical planning shall be for placement 3 hours for the left temporal bone and 9 hours for the right, and in 6 hours (mastoid). Morse taper prosthetic connection 4.0 platform implants behaved biomechanically desirably with 20o abutments in 2mm or 4mm heights. For the Morse taper connection 4.0 platform implants, their placement shall be in 6-9-12 hours, for the right temporal, and 12-3-6, for the left temporal, in order to achieve proper biomechanical behaviour. The Brånemark extraoral external hexagon implant, with 4.1 platform (normal or expanded) should preferrably be used with 20o abutments. (ii) The SiO2 5% may be added to the silicone preparation in order to slow maxillofacial prosthesis colour fading. The TiO2 brings visually significant changes and may be considered as an opacifier.

「當代的教育有被多數人當成一項藝術來實踐嗎？我們的教育有美嗎？教育如何成人之美？我們又如何觀看教育之美？」本研究採用藝術家、教師與教育研究者三位一體的研究取徑a/r/tography（art-based forms of educational inquiry）並混合多元研究方法、跨領域理論交互辯證以及表達性藝術實踐行動，旨在試圖超越目前科學家、藝術家、心理分析學家與教育家各自觀看世界的方式。本研究戮力創新教育美學研究取徑，以跨領域對話回應研究提問。 本研究借喻近代攝影史上最重要的變革演化：新紀實（The New Documentary），將其預設並倡議為一種後現代背景下之教育美學的多元視野（長鏡頭），以做為「教育的生命（神經性）、生成（藝術性）、生態（靈性）」的觀看之道。研究者並創作一系列新紀實攝影作品，期以多元真相涵化單一紀實的缺陷，改以不完美的長鏡頭與檔案的中性特質，一方面認清教育紀實的虛妄無明，另一方面則從教育的限制裡生出另隻眼。 教育美學所揭示的實踐智慧，大多來自「人如何描述眼前的世界」，故本研究深入梳理近二十年的神經科學對於視覺腦（visual brain）與靈性冥想（meditation）活動的研究成果，探究藝術家的實踐歷程以及進行藝術評論文本分析，並依多年田野經驗重新設計了一系列合作式彩繪曼陀羅（Cooperative Mandala Coloring）表達性藝術活動，以求能更充份反映榮格學派（Jungian Psychology）之共時性（synchronicity）理論與推演新時代靈性生態觀點，最終援引本質直觀的現象學（phenomenology）進行詮釋。 本研究成果特別關注青少年處於神經美學、藝術實踐與靈性成長之間精神流變（spirit flux）歷程，建議首先提供真誠友善的安全空間（safe space）、引入神馳（flow）的靈性體驗、以藝術活動滿足個體化的表達性需求（expressed needs）、在人我關係中創造利他的美感經驗。新紀實視野下的後現代教育美學倡議「自我陶養」、「德美一致」與「三性一體」，教育必需讓人有力量、有光芒、有夢想，始能真正啟動教育最美的樣子。 / This study borrows ‘the New Documentary’, the most important evolution in the photography history, as a metaphor to presuppose and advocate ‘the Lens’ as a diverse vision of education aesthetics under its post-modern context. It is utilized as a way to perceive the life (Neurological), the formation (Artistic), and ecology (Spiritual) of education. In this study, a series of the New Documentary work has been created. Two decades’ research on visual brain and meditation in neuroscience has been reviewed. The researcher also inquired into the artists’ journey of praxis and criticized numerous art reviews. Moreover, a series of Cooperative Mandala Coloring work has been redesigned based on the researcher’s years of practical teaching experience. This Cooperative Mandala Coloring, an expressive artistic activity, is adopted in present study to reflect Jungian Psychology’s theory of synchronicity, deduce the spiritual and ecological perspectives of new age, and interpret the phenomenology. The results of the present study particularly focus on adolescents’ spirit flux in neuro-aesthetics, art praxis, and spiritual development. The researcher proposes friendly safe space and spiritual experience in flow. It is also suggested that young individual’s expressed needs be fulfilled through artistic activities and altruistic aesthetic experience be created through relationships with others.

Network coding has emerged as an attractive alternative to routing because of the through put improvement it provides by reducing the number of channel uses. In a wireless scenario, in addition, further improvement can be obtained through Physical layer Network Coding (PNC), a technique in which nodes are allowed to transmit simultaneously, instead of transmitting in orthogonal slots. In this thesis, the design and analysis of network coding schemes are considered, for wireless two-way relaying, multi-user Multiple Access Relay Channel (MARC) and wireline networks. In a wireless two-way relay channel with PNC, the simultaneous transmissions of user nodes result in Multiple Access Interference (MAI) at there lay node. The harmful effect of MAI is the presence of signal set dependent deep channel fade conditions, called singular fade states, under which the minimum distance of the effective constellation at the relay become zero. Adaptively changing the network coding map used at the relay according to channel conditions greatly reduces the impact of this MAI. In this work, we obtain these adaptive PNC maps, which are finite in number ,by completing partially filled Latin Squares and using graph vertex coloring. Having obtained the network coding maps, the set of all possible channel realizations is quantized into a finite number of regions, with a specific network coding map chosen in a particular region and such a quantization is obtained analytically for 2λ-PSK signal set. The performance of the adaptive PNC scheme for two-way relaying is analyzed and tight high SNR upper bounds are obtained for the average end-to-end symbol error probability, in terms of the average error probability of a point-to-point fading channel. The adaptive PNC scheme is generalized for two-way relaying with multiple antennas at the nodes. As an alternative to the adaptive PNC scheme for two-way relaying, a Distributed Space Time Coding (DSTC) scheme is proposed, which effectively re-moves the effect of singular fade states at the transmitting nodes itself without any Channel State Information at the Transmitter (CSIT), and without any need to change the PNC map as a function of channel fade conditions. It is shown that the singular fade states can be viewed equivalently as vector subspaces of C2, which are referred to as the singular fade subspaces. DSTC design criterion to minimize the number of singular fade subspaces and maximize the coding gain is formulated and explicit low decoding complexity DSTC designs are provided. For the K-user MARC, in which K source nodes want to transmit messages to a destination node D with the help of are lay node R, a new PNC scheme is proposed. Use of a many-to-one PNC map with conventional minimum squared Euclidean distance decoding at D, results in a loss of diversity order due to error propagation from the relay node. To counter this, we propose a novel low complexity decoder which offers the maximum diversity order of two. Next, we consider wire line networks and explore the connections between linear network coding, linear index coding and discrete polymatroids, which are the multi-set analogue of matroids. We define a discrete polymatroidal network and show that a fractional vector linear solution over a field Fq exists for a network if and only if the network is discrete polymatroidal with respect to a discrete polymatroid representable over Fq.An algorithm to construct networks starting from certain class of discrete polymatroids is provided. Every representation over Fq for the discrete polymatroid, results in a fractional vector linear solution over Fq for the constructed network. It is shown that a linear solution to an index coding problem exists if and only if there exists a representable discrete polymatroid satisfying certain conditions which are determined by the index coding problem considered. El Rouayheb et. al. showed that the problem of finding a multi-linear representation for a matroid can be reduced to finding a perfect linear index coding solution for an index coding problem obtained from that matroid. Multi-linear representation of a matroid can be viewed as a special case of representation of an appropriate discrete polymatroid. We generalize the result of El Rouayheb et. al. by showing that the problem of finding a representation for a discrete polymatroid can be reduced to finding a perfect linear index coding solution for an index coding problem obtained from that discrete polymatroid.

Mes travaux de thèse s’inscrivent dans le cadre du projet ANR GRAPHEM1 (Graphemebased Retrieval and Analysis for PaleograpHic Expertise of Middle Age Manuscripts). Ilsprésentent une contribution méthodologique applicable à l'analyse automatique des écrituresanciennes pour assister les experts en paléographie dans le délicat travail d’étude et dedéchiffrage des écritures.L’objectif principal est de contribuer à une instrumetation du corpus des manuscritsmédiévaux détenus par l’Institut de Recherche en Histoire des Textes (IRHT – Paris) en aidantles paléographes spécialisés dans ce domaine dans leur travail de compréhension de l’évolutiondes formes de l’écriture par la mise en place de méthodes efficaces d’accès au contenu desmanuscrits reposant sur une analyse fine des formes décrites sous la formes de petits fragments(les graphèmes). Dans mes travaux de doctorats, j’ai choisi d’étudier la dynamique del’élément le plus basique de l’écriture appelé le ductus2 et qui d’après les paléographes apportebeaucoup d’informations sur le style d’écriture et l’époque d’élaboration du manuscrit.Mes contributions majeures se situent à deux niveaux : une première étape de prétraitementdes images fortement dégradées assurant une décomposition optimale des formes en graphèmescontenant l’information du ductus. Pour cette étape de décomposition des manuscrits, nousavons procédé à la mise en place d’une méthodologie complète de suivi de traits à partir del’extraction d’un squelette obtenu à partir de procédures de rehaussement de contraste et dediffusion de gradients. Le suivi complet du tracé a été obtenu à partir de l’application des règlesfondamentales d’exécution des traits d’écriture, enseignées aux copistes du Moyen Age. Il s’agitd’information de dynamique de formation des traits portant essentiellement sur des indicationsde directions privilégiées.Dans une seconde étape, nous avons cherché à caractériser ces graphèmes par desdescripteurs de formes visuelles compréhensibles à la fois par les paléographes et lesinformaticiens et garantissant une représentation la plus complète possible de l’écriture d’unpoint de vue géométrique et morphologique. A partir de cette caractérisation, nous avonsproposé une approche de clustering assurant un regroupement des graphèmes en classeshomogènes par l’utilisation d’un algorithme de classification non-supervisé basée sur lacoloration de graphe. Le résultat du clustering des graphèmes a conduit à la formation dedictionnaires de formes caractérisant de manière individuelle et discriminante chaque manuscrittraité. Nous avons également étudié la puissance discriminatoire de ces descripteurs afin d’obtenir la meilleure représentation d’un manuscrit en dictionnaire de formes. Cette étude a étéfaite en exploitant les algorithmes génétiques par leur capacité à produire de bonne sélection decaractéristiques.L’ensemble de ces contributions a été testé à partir d’une application CBIR sur trois bases demanuscrits dont deux médiévales (manuscrits de la base d’Oxford et manuscrits de l’IRHT, baseprincipale du projet), et une base comprenant de manuscrits contemporains utilisée lors de lacompétition d’identification de scripteurs d’ICDAR 2011. L’exploitation de notre méthode dedescription et de classification a été faite sur une base contemporaine afin de positionner notrecontribution par rapport aux autres travaux relevant du domaine de l’identification d’écritures etétudier son pouvoir de généralisation à d’autres types de documents. Les résultats trèsencourageants que nous avons obtenus sur les bases médiévales et la base contemporaine, ontmontré la robustesse de notre approche aux variations de formes et de styles et son caractèrerésolument généralisable à tout type de documents écrits. / My thesis work is part of the ANR GRAPHEM Project (Grapheme based Retrieval andAnalysis for Expertise paleographic Manuscripts of Middle Age). It represents a methodologicalcontribution applicable to the automatic analysis of ancient writings to assist the experts inpaleography in the delicate work of the studying and deciphering the writing.The main objective is to contribute to an instrumentation of the corpus of medievalmanuscripts held by “Institut de Recherche en Histoire de Textes” (IRHT-Paris), by helping thepaleographers specialized in this field in their work of understanding the evolution of forms inthe writing, with the establishment of effective methods to access the contents of manuscriptsbased on a fine analysis of the forms described in the form of small fragments (graphemes). Inmy PhD work, I chose to study the dynamic of the most basic element of the writing called theductus and which according to the paleographers, brings a lot of information on the style ofwriting and the era of the elaboration of the manuscript.My major contribution is situated at two levels: a first step of preprocessing of severelydegraded images to ensure an optimal decomposition of the forms into graphemes containingthe ductus information. For this decomposition step of manuscripts, we have proceeded to theestablishment of a complete methodology for the tracings of strokes by the extraction of theskeleton obtained from the contrast enhancement and the diffusion of the gradient procedures.The complete tracking of the strokes was obtained from the application of fundamentalexecution rules of the strokes taught to the scribes of the Middle Ages. It is related to thedynamic information of the formation of strokes focusing essentially on indications of theprivileged directions.In a second step, we have tried to characterize the graphemes by visual shape descriptorsunderstandable by both the computer scientists and the paleographers and thus unsuring themost complete possible representation of the wrting from a geometrical and morphological pointof view. From this characterization, we have have proposed a clustering approach insuring agrouping of graphemes into homogeneous classes by using a non-supervised classificationalgorithm based on the graph coloring. The result of the clustering of graphemes led to theformation of a codebook characterizing in an individual and discriminating way each processedmanuscript. We have also studied the discriminating power of the descriptors in order to obtaina better representation of a manuscript into a codebook. This study was done by exploiting thegenetic algorithms by their ability to produce a good feature selection.The set of the contributions was tested from a CBIR application on three databases ofmanuscripts including two medieval databases (manuscripts from the Oxford and IRHTdatabases), and database of containing contemporary manuscripts used in the writersidentification contest of ICDAR 2011. The exploitation of our description and classificationmethod was applied on a cotemporary database in order to position our contribution withrespect to other relevant works in the writrings identification domain and study itsgeneralization power to other types of manuscripts. The very encouraging results that weobtained on the medieval and contemporary databases, showed the robustness of our approachto the variations of the shapes and styles and its resolutely generalized character to all types ofhandwritten documents.

Diese Arbeit beschäftigt sich mit Scheduling von Tasks in Computersystemen. Wir untersuchen sowohl die in neueren Arbeiten betrachtete Zielfunktion zur Energieminimierung als auch die klassische Zielfunktion zur Lastbalancierung auf mehreren Prozessoren. Beim Speed-Scaling mit Sleep-State darf ein Prozessor, der zu jedem Zeitpunkt seine Geschwindigkeit anpassen kann, auch in einen Schlafmodus übergehen. Unser Ziel ist es, den Energieverbrauch zu minimieren. Wir zeigen die NP-Härte des Problems und klären somit den Komplexitätsstatus. Wir beweisen eine untere Schranke für die Approximationsgüte für eine spezielle natürliche Klasse von Schedules. Ferner entwickeln wir eine Familie von Algorithmen, die gute Approximationsfaktoren liefert, und zeigen, dass diese sogar Lösungen liefert, die optimal für die zuvor erwähnte Klasse von Schedules sind. Anschließend widmen wir unsere Aufmerksamkeit dem folgenden Termin-basierten Scheduling-Problem. Es seien mehrere Prozessoren gegeben, wobei jeder einzelne Prozessor zu jedem Zeitpunkt seine Geschwindigkeit anpassen kann. Ziel ist es wie zuvor, den Energieverbrauch des erzeugten Schedules zu minimieren. Für den Offline-Fall entwickeln wir einen optimalen Polynomialzeit-Algorithmus. Für das Online-Problem erweitern wir die zwei bekannten Ein-Prozessor-Algorithmen Optimal Available und Average Rate. Wir zeigen, dass diese den gleichen bzw. einen um die additive Konstante von eins vergrößerten kompetiven Faktor haben. Bei der Lastbalancierung auf mehreren Prozessoren betrachten wir Offline-Load-Balancing auf identischen Maschinen. Unser Ziel ist es, die Current-Load für temporäre Tasks mit identischem Gewicht zu minimieren. Wir zeigen, dass eine Lösung mit maximaler Imbalance von eins immer existiert und entwickeln einen effizienten Algorithmus, der solche Lösungen liefert. Zum Schluss beweisen wir die NP-Härte von zwei Verallgemeinerungen des Problems. / This thesis studies problems of scheduling tasks in computing environments. We consider both the modern objective function of minimizing energy consumption, and the classical objective of balancing load across machines. We first investigate offline deadline-based scheduling in the setting of a single variable-speed processor that is equipped with a sleep state. The objective is that of minimizing the total energy consumption. Apart from settling the complexity of the problem by showing its NP-hardness, we provide a lower bound of 2 for general convex power functions, and a particular natural class of schedules. We also present an algorithmic framework for designing good approximation algorithms. Furthermore, we give tight bounds for the aforementioned particular class of schedules. We then focus on the multiprocessor setting where each processor has the ability to vary its speed. We first study the offline problem and show that optimal schedules can be computed efficiently in polynomial time. Regarding the online problem and a natural class of power functions, we extend the two well-known single-processor algorithms Optimal Available and Average Rate. We prove that Optimal Available has the same competitive ratio as in the single-processor case. For Average Rate we show a competitive factor that increases by an additive constant of one compared to the single-processor result. With respect to load balancing, we consider offline load balancing on identical machines, with the objective of minimizing the current load, for temporary unit-weight jobs. The problem can be seen as coloring n intervals with k colors, such that for each point on the line, the maximal difference between the number of intervals of any two colors is minimal. We prove that a coloring with maximal difference at most one is always possible, and develop a fast polynomial-time algorithm for generating such a coloring. Lastly, we prove that two generalizations of the problem are NP-hard.