Les méthodes classiques de compression d’image sont communément basées sur des transformées fréquentielles telles que la transformée en Cosinus Discret (DCT) ou encore la transformée discrète en ondelettes. Nous présentons dans ce document une méthode originale basée sur une transformée combinatoire celle de Burrows-Wheeler(BWT). Cette transformée est à la base d’un réagencement des données du fichier servant d’entrée au codeur à proprement parler. Ainsi après utilisation de cette méthode sur l’image originale, les probabilités pour que des caractères identiques initialement éloignés les uns des autres se retrouvent côte à côte sont alors augmentées. Cette technique est utilisée pour la compression de texte, comme le format BZIP2 qui est actuellement l’un des formats offrant un des meilleurs taux de compression. La chaîne originale de compression basée sur la transformée de Burrows-Wheeler est composée de 3 étapes. La première étape est la transformée de Burrows-Wheeler elle même qui réorganise les données de façon à regrouper certains échantillons de valeurs identiques. Burrows et Wheeler conseillent d’utiliser un codage Move-To-Front (MTF) qui va maximiser le nombre de caractères identiques et donc permettre un codage entropique (EC) (principalement Huffman ou un codeur arithmétique). Ces deux codages représentent les deux dernières étapes de la chaîne de compression. Nous avons étudié l’état de l’art et fait des études empiriques de chaînes de compression basées sur la transformée BWT pour la compression d’images sans perte. Les données empiriques et les analyses approfondies se rapportant aux plusieurs variantes de MTF et EC. En plus, contrairement à son utilisation pour la compression de texte,et en raison de la nature 2D de l’image, la lecture des données apparaît importante. Ainsi un prétraitement est utilisé lors de la lecture des données et améliore le taux de compression. Nous avons comparé nos résultats avec les méthodes de compression standards et en particulier JPEG 2000 et JPEG-LS. En moyenne le taux de com-pression obtenu avec la méthode proposée est supérieur à celui obtenu avec la norme JPEG 2000 ou JPEG-LS / Common image compression standards are usually based on frequency transform such as Discrete Cosine Transform or Wavelets. We present a different approach for loss-less image compression, it is based on combinatorial transform. The main transform is Burrows Wheeler Transform (BWT) which tends to reorder symbols according to their following context. It becomes a promising compression approach based on contextmodelling. BWT was initially applied for text compression software such as BZIP2 ; nevertheless it has been recently applied to the image compression field. Compression scheme based on Burrows Wheeler Transform is usually lossless ; therefore we imple-ment this algorithm in medical imaging in order to reconstruct every bit. Many vari-ants of the three stages which form the original BWT-based compression scheme can be found in the literature. We propose an analysis of the more recent methods and the impact of their association. Then, we present several compression schemes based on this transform which significantly improve the current standards such as JPEG2000and JPEG-LS. In the final part, we present some open problems which are also further research directions

This paper deals with the usage of photovoltaics in positive energy buildings. The European Union published in 2010 a directive about the energy performance of buildings in which article 9 states that all member States shall ensure that by the end of 2020 all new buildings should be “nearly zero-energy” buildings (by the end of 2018 for public buildings). This kind of nearly zero-energy buildings is starting to develop in France under the name “BEPOS” (which stands for POSitive Energy Building, in French), and this is the name that will be used in this document. 288 projects have been certified “BEPOS” as of 2012, according to the ADEME which published a map of all the BEPOS buildings in France (the ADEME is a French agency for the environment and the energy utilization, which is a major actor in the French energy policy, often deciding where to allocate funds). To be a BEPOS, these buildings need to produce electricity on site and photovoltaics are often considered as one of the most mature and competitive technology to do so, also the most used. The purpose of this study is to demonstrate that photovoltaics are an economically viable means to reach the BEPOS quality label, and to provide data to quantify the cost and performance of a photovoltaic system. To achieve that, the technological and market conditions of photovoltaics in France are reviewed, and techno-economic calculations are made using data provided by solar and construction companies.

A climate-neutral city can be viewed at in many different aspects. This report investigates the greenhouse gas, exergy and energy balance for both heat pumps and district heat supply at local, national and methane gas perspectives of the energy conversion processes. Through a numerical grey box model of a geographical information system based urban district. There seven different passive-, nearly zero-, and plus-energy residential buildings are implemented. That are developed and annually simulated in the IDA ICE software. There, thermal transmittance and building geometry are the most urgent parameters that impacts the space heating demand and energy performance. They are estimated by current and proposed primary energy weight factors where the geometry shape is undefined, while the altitude impact’s the building's energy, exergy, and greenhouse gas balance. Therefore high-rise building's energy performance are poorer than low-rise buildings, simultaneously as heat pump supply enables higher altitude than district heating. Other energy savings occur through additional energy-efficient technologies, energy generating technologies and soft tools that change residents’ behavior. The investigated urban district is placed in the Swedish city Gävle, which meets residents’ demand for approximately 6000 apartments without additional service. It is a plus energy district for heat pump supply and passive energy for district heating supply. Although the district heated urban district electricity-saving towards heat pump corresponds to 32 percent of the urban district's total facility and household electricity utilization. The energy analysis include the perspective of the facility’s energy utilization and generation, and the perspectives of residents’ energy utilization and recovery from their waste resource production. This makes the urban district exergy productive and carbon-negative during the operating phase, regardless of emission value and heat supply technology, since the facility perspective compensates for the residents’ electricity utilization and consumption of goods. Therefore, there are no need for tree plantation as compensation of greenhouse gas pollution since the carbon negativity corresponds to between 2 to 154 hectares of forest. The study is therefore relevant for other geographical locations in Sweden depending on geographical location, heat supply technology and emission value from the primary energy conversion processes. / <p>Förstudie i future heat projekt angående Framtidens klimatsmarta stad genom klimatneutral bebyggelse med fjärrvärme.</p>

This thesis deals with design algorithms for filter banks based on optimization. The design specifications consist of the perfect reconstruction and frequency response specifications for finite impulse response (FIR) analysis and synthesis filters. The perfect reconstruction conditions are formulated as a set of linear equations with respect to the analysis filters’ coefficients and the synthesis filters’ coefficients. Five design algorithms are presented. The first three are based on an unconstrained optimization of performance indices, which include the perfect reconstruction error and the error in the frequency specifications. The last two algorithms are formulated as constrained optimization problems with the perfect reconstruction error as the performance index and the frequency specifications as constraints. The performance of the five algorithms is evaluated and compared using six examples; these examples include uniform filter bank, compatible non-uniform filter bank and incompatible non-uniform filter bank designs. The evaluation criteria are based on distortion and aliasing errors, the magnitude response characteristics of analysis and synthesis filters, the computation time required for the optimization, and the convergence of the performance index with respect to the number of iterations. The results show that the five algorithms can achieve almost perfect reconstruction and can meet the frequency response specifications at an acceptable level. In the case of incompatible non-uniform filter banks, the algorithms have challenges to achieve almost perfect reconstruction. / Graduate

Almost p-ary perfect and nearly perfect sequences are equivalent to certain relative difference sets and direct product difference sets, respectively. This feature enables Chee, Tan and Zhou to determine the existence status of those sequences by using the tools of Design Theory. In particular, they determined the existence status of almost p-ary perfect and nearly perfect sequences of period n+1 for n 100, except some open cases in [6]. In this thesis, we obtained a set of Diophantine equations in integers while observing relative difference sets, and proved nonexistence of almost p-ary perfect sequences of period n + 1 for n (50,76,94,99,100).Also, we observed that it was possible to extend Diophantine equations that we used for relative difference sets to the direct product difference sets, thereby proved the nonexistence of almost p-ary nearly perfect sequences of type II of period n + 1 for p = 2, p = 3 and p = 5 at certain values of n. As a result, we answered two questions posed by Chee, Tan and Zhou in [6].

Dans cette thèse nous introduisons la notion de fibré tt* (E,D,S), de fibré tt* métrique (E,D,S,g) et de fibré tt* symplectique (E,D,S,w) sur un fibré vectoriel E au-dessus d'une variété complexe, dans le langage de la géométrie différentielle réelle. Grâce à cette notion on obtient une correspondance entre des fibrés tt* métriques et des applications pluriharmoniques admissibles de (M,J) dans l'espace symétrique pseudo-Riemannien GL(r,R)/O(p,q), avec (p,q) la signature de la métrique g. En utilisant ce résultat on obtient dans le cas où M est compact Kählérienne, un résultat de rigidité, puis un cas particulier du théorème de Lu. <br />De plus nous étudions des fibrés tt* sur le fibré tangent TM et caractérisons une classe spéciale qui contient les variétés spéciales complexes et les variétés nearly Kählériennes plates, et la sous-classe qui admet un fibré tt* métrique ou symplectique. En outre on analyse les fibrés tt* qui proviennent de variations de structures de Hodge (VHS) et de fibrés harmoniques. Pour les fibrés harmoniques, la correspondance permet de généraliser un résultat de Simpson. L'application pluriharmonique associée à une variété spécialement Kählérienne reliée à l'application de Gauß duale, et celle associée à une VHS de poids impair est l'application de périodes. Si la structure complexe n'est pas intégrable, on doit généraliser la notion de pluriharmonicité. <br />Hors la rigidité ces résultats sont généralisés au cas para-complexe.

On étudie des variétés presque hermitiennes de dimension 6 qui admettent une réduction supplémentaire à SU(3), induite par la partie de type (3,0) de la différentielle de la forme de Kähler dω. On se sert du fait constaté par Hitchin qu'une 2-forme ω et une 3-forme ψ, d'un certain type algébrique, sont suffisantes pour définir une structure SU(3) sur une variété de dimension 6, ainsi que du fait démontré par Chiossi, Salamon que les différentielles de ω, ψ mais aussi de φ, le dual de Hodge de ψ, déterminent le 1-jet de cette structure SU(3) en tout point. L'exemple privilégié de cette situation, où la réduction est globale, est celui des variétés « nearly Kähler » non kähleriennes en dimension 6, appelées par nous variétés de Gray. On classifie les variétés de Gray homogènes ce qui permet de résoudre une ancienne conjecture de Gray et Wolf : toutes les variétés strictement « nearly Kähler » homogènes sont des espaces 3-symétriques. Un autre résultat concerne une sous-variété naturelle de l'espace de twisteurs d'une variété presque hermitienne. Cet « espace de twisteurs réduit » est muni d'une structure presque complexe naturelle qu'on montre n'être intégrable que si la variété est localement conforme à une variété kählerienne, Bochner-plate ou à la sphère S6. En passant, on montre que les variétés de type W1+W4 dans la classification de Gray, Hervella (où W1 est la classe des variétés « nearly-Kähler » et W4 la classe des variétés localement conformément kähleriennes) sont localement conformes à des variétés nearly-Kähler, en dimension 6.

We study some Hölderian functional central limit theorems for the polygonal partial sum processes built on a first order nearly nonstationary autoregressive process and its least squares residuals Innovations are i.i.d. centered and at least square-integrable innovations. Two types of models are considered. For the first type model we prove that the limiting process depends on Ornstein – Uhlenbeck one. In the second type model, the convergence to Brownian motion is established in Hölder space in terms of the rate of coefficient and the integrability of the residuals. We also investigate some epidemic change in the innovations of the first order nearly nonstationary autoregressive process . We build the alpha-Hölderian uniform increments statistics based on the observations and on the least squares residuals to detect the short epidemic change in the process under consideration. Under the assumptions for innovations we find the limit of the statistics under null hypothesis, some conditions of consistency and we perform a test power analysis. / Disertacijoje nagrinėjami dalinių sumų laužčių procesai sudaryti iš pirmos eilės beveik nestacionaraus proceso bei jo mažiausių kvadratų liekanų. Inovacijos yra nepriklausomi, vienodai pasiskirstę ir bent kvadratu integruojami atsitiktiniai dydžiai su nuliniu vidurkiu. Įrodomos funkcinės ribinės teoremos šiems laužčių procesams Hiolderio erdvėje. Nagrinėjami du beveik nestacionaraus proceso atvejai. Vienu atveju įrodoma, kad ribinis procesas priklauso nuo Ornsteino–Uhlenbecko proceso. Kitu atveju, įrodomas konvergavimas į Brauno judesį Hiolderio erdvėje, atsižvelgiant į koeficiento divergavimo greitį bei inovacijų integruojamumą. Toliau nagrinėjamas epideminio pasikeitimo modelis beveik nestacionaraus pirmos eilės autoregresinio proceso inovacijoms. Nagrinėjami du modeliai. Iš stebėjimų bei liekanų konstruojama tolydžiųjų prieaugių alpha-Hiolderio statistika. Remiantis prielaidomis inovacijoms, randama statistikos ribinis procesas prie nulinės hipotezės, suderinamumo sąlygos, atliekama galios analizė.

Disertacijoje nagrinėjami dalinių sumų laužčių procesai sudaryti iš pirmos eilės beveik nestacionaraus proceso bei jo mažiausių kvadratų liekanų. Inovacijos yra nepriklausomi, vienodai pasiskirstę ir bent kvadratu integruojami atsitiktiniai dydžiai su nuliniu vidurkiu. Įrodomos funkcinės ribinės teoremos šiems laužčių procesams Hiolderio erdvėje. Nagrinėjami du beveik nestacionaraus proceso atvejai. Vienu atveju įrodoma, kad ribinis procesas priklauso nuo Ornsteino–Uhlenbecko proceso. Kitu atveju, įrodomas konvergavimas į Brauno judesį Hiolderio erdvėje, atsižvelgiant į koeficiento divergavimo greitį bei inovacijų integruojamumą. Toliau nagrinėjamas epideminio pasikeitimo modelis beveik nestacionaraus pirmos eilės autoregresinio proceso inovacijoms. Nagrinėjami du modeliai. Iš stebėjimų bei liekanų konstruojama tolydžiųjų prieaugių alpha-Hiolderio statistika. Remiantis prielaidomis inovacijoms, randama statistikos ribinis procesas prie nulinės hipotezės, suderinamumo sąlygos, atliekama galios analizė. / We study some Hölderian functional central limit theorems for the polygonal partial sum processes built on a first order nearly nonstationary autoregressive process and its least squares residuals Innovations are i.i.d. centered and at least square-integrable innovations. Two types of models are considered. For the first type model we prove that the limiting process depends on Ornstein – Uhlenbeck one. In the second type model, the convergence to Brownian motion is established in Hölder space in terms of the rate of coefficient and the integrability of the residuals. We also investigate some epidemic change in the innovations of the first order nearly nonstationary autoregressive process . We build the alpha-Hölderian uniform increments statistics based on the observations and on the least squares residuals to detect the short epidemic change in the process under consideration. Under the assumptions for innovations we find the limit of the statistics under null hypothesis, some conditions of consistency and we perform a test power analysis.

Made available in DSpace on 2016-12-08T16:18:47Z (GMT). No. of bitstreams: 1 Diele.pdf: 1205275 bytes, checksum: 1e1958313e7636dd1c4b73f67fb5df5a (MD5) Previous issue date: 2011-08-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the present investigation was intended to observe and analyze the graphic representation of four (4) blind children. The goal was to pinpoint the existing differences in the logic process of those who were born blind (nearly totally blind) and those who lost their sight at some age (older totally blind). The research took place at the Escola de Educação Especial Professor Osny Macedo Saldanha , kept by the Instituto Paranaense de Cegos , in which the researcher is the Arts Program Teacher since 2006. At first, a social historical profile is rescued and presented, based on daily basis reports of the Art classes, pointing the importance of mediation in this process. This research was fundamented in some aspects about children s drawings pointed by the Authors Luquet (1969), Darras (1998), Gombrich (1999), Arnheim (1980), Wilson & Wilson (1997) and Cox (2007). Three drawing teaching methods for blind children are also presented: Duarte s (2005) research, the methodology created by Bardisa (1992), and the notes about the practice of tactile drawings made by Lima (2001). The investigation took place with a pre-collection that consisted in: propositions of drawing their own bodies, drawings off the top of their heads objects, drawings after touching miniatures, and drawings places and actions. From the pre-collection, a history based on the students daily lives was created, containing drawings elements already known by them, but this time presented as a text to be drawn. In the data collection it was observed that: a) nearly totally blind and older totally blind students use different resources of graphic representation; b) the narrative is necessary in the understanding of the graphic representation of the nearly totally blind; c) the older totally blind s drawings that had previous experiences drawing resemble the nearly totally blind s drawings; d) teaching a blind child to draw requires a systematic teaching method; e) the way students were stimulated as a child and the social-historical-cultural context that they live in are determinant in their capacity of representing the world by drawing / Na presente investigação, buscou-se observar e analisar a representação gráfica de quatro alunos cegos já iniciados no desenho. O objetivo foi apontar as diferenças presentes nos processos de raciocínio entre aqueles que nasceram cegos (cegos precoces) e aqueles que perderam a visão com determinada idade (cegos tardios). A pesquisa ocorreu nas dependências da Escola de Educação Especial Professor Osny Macedo Saldanha, mantida pelo Instituto Paranaense de Cegos, na qual a pesquisadora é professora de Artes desde 2006. No primeiro momento, é apresentado um resgate histórico-social com relatos de vivências das aulas de Artes, salientando a importância da mediação neste processo. Esta pesquisa fundamentou-se em alguns aspectos do desenho infantil apontados pelos autores Luquet (1969), Darras (1998), Gombrich (1999), Arnheim (1980), Wilson e Wilson (1997) e Cox (2007). São apresentadas também três propostas metodológicas de ensino de desenho para cegos: a pesquisa de Duarte (2005), a metodologia criada por Bardisa (1992) e os apontamentos dos treinos de desenhos táteis realizados por Lima (2001). A investigação iniciou-se com uma précoleta que consistiu em: proposições do desenho de seu corpo, desenhos de memória de objetos, desenhos no contato com miniaturas e desenhos de espaços e ações. A partir da pré-coleta, foi criada uma história baseada no dia a dia dos alunos, contendo elementos de desenho já conhecidos por eles, mas que agora estavam apresentados em forma de um texto a ser ilustrado. Observou-se na coleta de dados que: a) alunos cegos precoces e tardios utilizam recursos diferentes de representação gráfica; b) a narrativa se faz necessária no entendimento da representação gráfica dos alunos cegos precoces; c) os desenhos dos alunos cegos tardios que tiveram experiências anteriores com o desenho se assemelham aos desenhos de crianças videntes; d) ensinar desenho para uma criança cega requer um método de ensino sistemático; e) a forma com que os alunos foram estimulados quando pequenos e o contexto sócio-histórico-cultural em que vivem são determinantes na sua capacidade de representar o mundo pelo desenho