• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 336
  • 184
  • 184
  • 90
  • 44
  • 41
  • 29
  • 25
  • 17
  • 11
  • 11
  • 10
  • 9
  • 6
  • 6
  • Tagged with
  • 1095
  • 196
  • 138
  • 100
  • 97
  • 73
  • 65
  • 65
  • 64
  • 63
  • 57
  • 55
  • 55
  • 52
  • 50
  • 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.
281

Elastographie haute-résolution pour l'évaluation des propriétés élastiques de la cornée et de la peau

Nguyen, Thu-Mai 06 December 2012 (has links) (PDF)
Ces travaux de thèse portent sur la mise au point d'une technique d'élastographie quantitative à haute résolution pour l'estimation des propriétés biomécaniques de la cornée et de la peau. Pour cela, nous avons implémenté la méthode Supersonic Shear wave Imaging (SSI) à des fréquences ultrasonores atteignant 20 MHz. L'élastographie SSI consiste à déterminer la rigidité d'un milieu à partir de la vitesse de propagation d'une onde de cisaillement dans ce milieu. La géométrie de la cornée et de la peau, qui sont des organes d'épaisseur submillimétrique, impose un guidage des ondes de cisaillement le long des interfaces de ces organes, engendrant des phénomènes dispersifs. Nous avons donc dans un premier temps développé un modèle permettant de calculer quantitativement le module d'Young à partir des courbes de dispersion de l'onde de cisaillement. Dans un second temps, nous avons mis en application l'élastographie SSI pour obtenir des cartographies des propriétés élastiques de cornées porcines ex vivo et in vivo et du derme humain in vivo. Le comportement élastique anisotrope et non-linéaire de ces deux tissus a ainsi pu être observé. Nous avons ensuite réalisé une étude préclinique en ophtalmologie, qui démontre la faisabilité d'utiliser l'élastographie SSI pour évaluer in vivo le durcissement cornéen induit par un traitement appelé " cross-linking de collagène cornéen ". Enfin, nous avons mené deux études cliniques en dermatologie. L'une a permis d'étudier les variations d'élasticité du derme au cours du vieillissement, l'autre concerne la caractérisation de lésions cutanées.
282

L'évolution modulaire des protéines : un point de vue phylogénétique

Sertier, Anne-Sophie 12 September 2011 (has links) (PDF)
La diversité du monde vivant repose pour une large part sur la diversité des protéines codées dans les génomes. Comment une telle diversité a-t-elle été générée ? La théorie classique postule que cette diversité résulte à la fois de la divergence de séquence et de la combinatoire des arrangements de protéines en domaines à partir de quelques milliers de domaines anciens, mais elle n'explique pas les nombreuses protéines orphelines.Dans cette thèse, nous avons étudié l'évolution des protéines du point de vue de leur décomposition en domaines en utilisant trois bases de données : HOGENOM (familles de protéines homologues), Pfam (familles de domaines expertisées) et ProDom (familles de modules protéiques construites automatiquement). Chaque famille d'HOGENOM a ainsi été décomposée en domaines de Pfam ou modules de ProDom. Nous avons modélisé l'évolution de ces familles par un réseau Bayésien basé sur l'arbre phylogénétique des espèces. Dans le cadre de ce modèle, on peut reconstituer rigoureusement les scénarios d'évolution les plus probables qui reflètent la présence ou l'absence de chaque protéine, domaine ou module dans les espèces ancestrales. La mise en relation de ces scénarios permet d'analyser l'émergence de nouvelles protéines en fonctions de domaines ou modules ancestraux. L'analyse avec Pfam suggère que la majorité de ces événements résulte de réarrangements de domaines anciens, en accord avec la théorie classique. Cependant une part très significative de la diversité des protéines est alors négligée. L'analyse avec ProDom, au contraire, suggère que la majorité des nouvelles protéines ont recruté de nouveaux modules protéiques. Nous discutons les biais de Pfam et de ProDom qui permettent d'expliquer ces points de vue différents. Nous proposons que l'émergence de nouveaux modules protéiques peut résulter d'un turn-over rapide de séquences codantes, et que cette innovation au niveau des modules est essentielle à l'apparition de nombreuses protéines nouvelles tout au long de l'évolution.
283

La agregación modular como mecanismo proyectual residencial en España: el taller de arquitectura

García Hernández, Pedro 01 March 2013 (has links)
El Congrés d'Otterlo de 1959 va significar el principi de la fi de la Carta d'Atenes. Els arquitectes del Team 10 van plantejar, a partir d'aquest moment, una nova forma de relació entre edifici i ciutat. La ciutat tradicional, la "kashba" i les medines, van ser reinterpretades com a opcions per futures reflexions de relació, a diverses escales, entre l’hàbitat i el seu entorn. D'aquesta manera l'arquitectura, a través de l’autonomia que li atorguen les seves pròpies lleis, va ser capaç; d'establir diàleg amb el territori i amb la societat. La voluntat de canvi cap a una nova societat i una nova forma de fer ciutat van introduir conceptes arquitectònics totalment nous. Els sistemes agregatius, van ser les propostes més utilitzades com a resposta a les qüestions plantejades. L'activitat edilícia va ser vista com una escala intermèdia de relació a través de la unitat d’agregació. Mig segle més tard, tota una sèrie d'arquitectes reinterpreten molts d'aquests conceptes. Les noves tecnologies aplicades a l'activitat arquitectònica han fet una nova relectura d'aquests sistemes. La incorporació de conceptes matemàtics i conceptes estètics, com el collage arquitectònic, són fonamentals per entendre la manera com plantegen estudis com OMA i, especialment, SANAA, la resposta arquitectònica als problemes plantejats perla societat actual. La tesis profunditza en la manera en que totes aquestes idees plantejades a partir dels anys seixanta, i que encara perduren com a mètode de treball, van arribar al nostre país i com es van desenvolupar, de forma embrionària, unes propostes que van sorprendre inclús més enllà de les nostres fronteres. A la península ibèrica deis anys seixanta, hi va haver cert interès pels sistemes modulars. En el camp teòric, s'han de destacar les propostes de Rafael Leoz, les seves publicacions i llibres. En el camp pràctic, arquitectes com Bonet Castellana, Coderch, Sáez de Oiza i Corrales i Molezun, van demostrar la connexió amb las propostes que es desenvolupaven als països veïns. Tot i així, va ser el Taller d'Arquitectura el que va projectar i executar un major número d'exemples en una línea clara, treballant els sistemes agregatius i el desenvolupament d'aquests a partir d'una investigació modular. El barri Gaudí de Reus serà un primer intent de recerca de lleis agregatives. A la Muralla Roja i a l'edifici Xanadú, es van començar a explorar els habitatges i a concretar el mòdul que finalment van aplicar al Castell de Sitges. La culminació del sistema agregatiu es realitzarà a la Ciudad en el Espacio i a Walden 7, on s'arriba a la solució més rica i clara de totes les anteriors. Li seguirà la Petit Cathedral, on la recerca de la monumentalitat s'anteposa a les pròpies lleis agregatives, i que serà el final de tota una dècada d'investigació. L’anàlisi d'aquestes obres, així com la metodologia utilitzada i l'organització del propi Taller són fonamentals per entendre l'evolució d'aquestes propostes que van demostrar el geni i caràcter d’un jove Ricardo Bofill al davant del Taller de Arquitectura. / El Congreso de Otterlo de 1959 significó el principio del fin de la Carta de Atenas. Los arquitectos del Team 10 plantearon, a partir de ese momento una nueva forma de relación entre edificio y ciudad. La ciudad tradicional, la "kashba" y las medinas, fueron reinterpretadas como opciones para futuras reflexiones de relación, a diversas escalas, entre el hábitat y su entorno. De este modo la arquitectura, a través de la autonomía que le otorgan sus propias leyes, fue capaz de establecer diálogo con el territorio y con la sociedad. La voluntad de cambio hacia una nueva sociedad y una nueva forma de hacer ciudad introdujeron conceptos arquitectónicos totalmente nuevos. Los sistemas agregativos, fueron las propuestas más utilizadas como respuesta a las cuestiones planteadas. La actividad edilicia fue vista como una escala intermedia de relación a través de la unidad de agregación. Pasado medio siglo, toda una serie de arquitectos reinterpretan actualmente muchos de estos conceptos. Las nuevas tecnologías aplicadas a la actividad arquitectónica, han hecho una nueva relectura de dichos sistemas. La incorporación de conceptos matemáticos y conceptos estéticos como el collage arquitectónico son fundamentales para entender la manera de cómo plantean estudios como OMA y, especialmente, SANAA, la respuesta arquitectónica a los problemas planteados por la sociedad actual. La tesis profundiza en la manera en que todas estas ideas planteadas a partir de los años sesenta, y que aún perduran como método de trabajo, llegaron a nuestro país y como se desarrollaron, de forma embrionaria, unas propuestas, que asombraron incluso más allá de nuestras fronteras. En la península ibérica de los años sesenta, hubo un cierto interés por los sistemas modulares. En el campo teórico, hay que destacar las propuestas de Rafael Leoz y sus publicaciones y libros. En la práctica, arquitectos como Bonet Castellana, Coderch, Sáez de Oiza y Corrales y Molezun, demostraron la conexión con las propuestas que se desarrollaban en los países vecinos. Sin embargo, fue el Taller de Arquitectura, el que proyectó y ejecutó un mayor número de ejemplos en una línea clara, trabajando los sistemas agregativos y el desarrollo de estos a partir de una investigación modular. El barrio Gaudí de Reus será un primer intento de búsqueda de leyes agregativas. En la Muralla Roja y en el edificio Xanadú, comenzaron a explorar las viviendas y a concretar el modulo que finalmente aplicaron en el Castell de Sitges. La culminación del sistema agregativo se realizara en la Ciudad en el Espacio y en Walden 7, donde se llega a la solución más rica y clara de todas las anteriores. Le seguirá la Petit Cathedral, donde la búsqueda de la monumentalidad se antepone a las propias leyes agregativas y que será el fin de toda una década de investigación. El análisis de estas obras, así como la metodología utilizada y la organización del propio Taller son fundamentales para entender la evolución de estas propuestas que demostraron el genio y carácter de un joven Ricardo Bofill al frente del Taller de Arquitectura. / The Otterlo Congress of 1959 marked the beginning of the end of the Athens Charter. From then on, the Team 10 architects raised a new form of relationship between the building and the city. The traditional city, the "Kashba" and the medinas, were reinterpreted as options for future relationship considerations between habitat and environment at different scales. Thereby architecture, by virtue of the autonomy granted by its own laws, was able to establish a dialogue with the territory and with society. The will to change towards a new society and a new way of city-making introduced totally new architectural concepts. Aggregative systems were the most commonly used proposals in response to the issues raised. The building activity was seen as an intermediate relationship scale through the aggregation unit. Half a century later, a vast number of architects currently reinterpret many of these concepts. New technologies applied to architectural activity have generated a new reading of such systems. The incorporation of mathematical and aesthetic concepts such as architectural collage are fundamental for the understanding of the way in which studios such as OMA and especially Saana set out the response to the problems posed by today's society. The thesis delves into the manner in which all the ideas raised in the sixties- and which still remain as working methods- reached our country and how they embryonically developed proposals that stunned even beyond our borders. In the lberian Peninsula of the sixties there was some interest in modular systems. In the theoretical field, Rafael Leoz's proposals and publications are noteworthy. In the practical field, architects such as Bonet Castellana, Coderch,Sáez de Oiza y Corrales and Molezún showed the connection with the proposals that were developed in the neighboring countries. However, it was the Taller de Arquitectura [Architecture Workshop], which planned and executed a large number of clear examples working with aggregative systems and their development on the basis of a modular research. The Gaudí neighborhood in Reus would become the first attempt to search aggregative laws. The Muralla Roja [Red Wall] and the Xanadú building, began to explore the dwellings and to settle the module that would then be applied on the Castell de Sitges [Sitges Castle]. The culmination of aggregative system would be accomplished in the Ciudad en el Espacio [The City in Space] and in the Walden 7, where the richest and clearest solution among all the previous is reached. They were followed by the Petite Cathédrale, wherein the search for monumentality preempts aggregative laws themselves and that will be the end of a whole decade of research. The analysis of these works, as well as the methodology and the organization of the Taller itself are key to understand the evolution of proposals which proved the genius and character of a young Ricardo Bofill leading the Taller de Arquitectura.
284

The Folding and Binding Partners of the Perlecan SEA Module

Diaz, Ariel 06 September 2012 (has links)
Sperm protein, enterokinase and agrin (SEA) modules are small folds within large heavily glycosylated modular proteins. Because decreased expression of SEA-containing proteins such as perlecan (PLN) can lead to diseases such as Schwartz-Jampel syndrome (SJS), characteristics of the PLN SEA module including folding, potential for autocleavage, and protein binding were studied. Sequence analyses, recombinant protein evaluation, and a yeast two-hybrid screen were used to study the PLN SEA module and compare it to the mucin (MUC) 1 SEA module. In silico modeling of the PLN SEA module demonstrated a well conserved α/β sandwich fold. Experiments with expressed proteins showed that unlike MUC1, the PLN SEA module does not autocleave. Two-hybrid screening identified four “high confidence” proteins as potential binding partners which were explored in preliminary experiments. Together, these results demonstrate that PLN SEA module is unique and its properties cannot be generalized with other SEA module proteins such as MUC1.
285

Automated Analysis of Automotive Read-Out Data for Better Decision Making

Saleem, Muhammad January 2011 (has links)
The modern automobile is a complex electromechanical system controlled by control systems which consist of several interdependent electronic control units (ECUs). Analysis of the data generated by these modules is very important in order to observe the interesting patterns among data. At Volvo Cars Corporation today, diagnostic read-out data is retrieved from client machines installed at workshops in different countries around the world. The problem with this data is that it does not show a clear picture as what is causing what i.e. tracking the problem. Diagnostic engineers at Volvo Cars Corporation perform routine based statistical analysis of diagnostic read-out data manually, which is time consuming and tedious work. Moreover, this analysis is restricted to basic level mainly statistical analysis of diagnostic readout data. We present an approach based on statistical analysis and cluster analysis. Our approach focused on analysing the data from a pure statistical stand-point to isolate the problem in diagnostic read-out data, thereby helping to visualize and analyse the nature of the problem at hand. Different general statistical formulae were applied to get meaningful information from large amount of DRO data. Cluster analysis was carried out to get clusters consisting of similar trouble codes. Different methods and techniques were considered for the purpose of cluster analysis. Hierarchical and non-hierarchical clusters were extracted by applying appropriate algorithms. The results obtained from the thesis work show that the diagnostic read-out data consist of independent and interdependent fault codes. Groups were generated which consist of similar trouble codes. Furthermore, corresponding factors from freeze frame data which shows significant variation for these groups were also extracted. These faults, groups of faults and factors were later interpreted and validated by diagnostic engineers.
286

The remote control ofmobile robot on theInternet

Zhong, Shengtong January 2007 (has links)
During last decades, the Internet teleobotics has been growing at an enormous ratedue to the rapid improvement of Internet technology. This paper presents theinternet-based remote control of mobile robot. To face unpredictable Internet delaysand possible connection rupture, a direct continuous control based teleoperationarchitecture with “Speed Limit Module” (SLM) and “Delay Approximator” (DA) isproposed. This direct continuous control architecture guarantees the path error of therobot motion is restricted within the path error tolerance of the application.Experiment results show the feasibility and effectiveness of this direct Internet controlarchitecture in the real Internet environment.
287

Design andImplementation of a Module Generator for Low Power Multipliers

Sun, Kaihong January 2003 (has links)
Multiplication is an important part of real-time system applications. Various hardware parallel multipliers used in such applications have been proposed. However, when the operand sizes of the multipliers and the process technology need to be changed, the existing multipliers have to be redesigned. From the point of library cell reuse, this master thesis work aims at developing a module generator for parallel multipliers with the help of software programs. This generator can be used to create the gate-level schematic for fixed point two's complement number multipliers. Based on the generated schematic, the entire multiplier can be implemented by small manual intervention. This feature can reduce the time of chip design. The design phases consist of the logic, circuit and physical designs. The logic design includes gate-level schematic generation with C and SKILL programs and structural VHDL-code descriptions as well as validation. The circuit and physical design are custom in Cadence and the routing uses automatic place and route tools. To demonstrate the design method, an 18 by 18-bit modified Booth recoded multiplier was implemented in 0.18 µm CMOS process with a supply voltage of 1.2 V and simulated using simulator (Spectre). The number of integrated transistors is 13000 and the active area is 85000 µm2. The postlayout simulation shows the critical path with a delay of 17 ns.
288

VHDL Implementation of a Fast Adder Tree

Dacheng, Chen January 2005 (has links)
This thesis discusses the design and implementation of a VHDL generator for Wallace tree with (3:2) counter modules and (2:2) counter modules to solve fast addition problem. The basic research has been carried out by MATLAB programming environment and automatic generation of VHDL file based on the result obtained from MATLAB simulation. MODELSIM has been used for compilation and simulation of the VHDL file.
289

Drive System of Electrical Lighter Vehicle with Brushless DC Machine

Lu, Wei-i 05 February 2010 (has links)
A drive system of the electrical lighter vehicle with the brushless DC machine is developed in the thesis. The system consists of a control unit based on a digital signal processor (DSP) and a drive module which combines a drive circuit, a brushless DC machine, and associated wheels. The motive power is delivered directly to the wheels without a power transmission system. The driving comments and the monitored signals between the modules and the control unit are communicated by the Controller Area Network (CAN) Bus. Each module can be controlled independently. By modifying the software of the system, the proposed drive system can be implemented in various electrical vehicles without changing circuit design. The developed system can be operated at forward, backward, and rotating motions. By limiting the armature current, the vehicle can be operated under the power saving mode. During the regenerative braking, the battery set is charged by the regenerative current. The experimental results show that the highest efficiency of the machine is 80 % with the motoring operation.
290

Three essays concerning economic analysis associated with the supply chain

Sherwell Cabello, Pablo 02 June 2009 (has links)
Analyzing different aspects of the supply chain aids in understanding how firms behave, interact and respond within an industry. Some concepts used to carry out this analysis include asymmetric price transmission, event study methodology and event costing analysis. Each of these topics is discussed in this dissertation, presented as a set of three separate papers. The first paper analyzes asymmetric price transmission and elasticities of price transmission at the farm-retail level for whole and two percent milk in selected cities in the United States. The theoretical core of this paper relies on a comparison between the traditional Houck approach and the error correction model proposed by von Cramon- Taubadel and Fahlbusch. We reject the null hypothesis of symmetry for each product and city under both approaches. We also find little evidence of statistical superiority between the classic Houck approach and the error correction model. The second paper uses financial market event study methodology to calculate the economic impact on the supply chain related to one of the worst disease outbreaks in the food industry in the United States. This event began on November 3, 2003, when the Associated Press reported a hepatitis advisory in the Beaver Valley, Pennsylvania. This outbreak directly involved two publicly traded companies: Prandium and Sysco. The market model is used as the main foundation of the economic analysis. There is no evidence of abnormal rates of return or spillover effects in relation to the outbreak. However, there is evidence that volatility of returns increases after the event. The third paper develops a general conceptual economic module to quantify the impact of an animal disease outbreak. This study develops a generic economic module, which estimates cost in the face of a simulated animal disease outbreak under different mitigation strategies. This model was subsequently applied in a case study: a hypothetical case of a foot-and-mouth (FMD) outbreak in the Texas Panhandle analyzed under five different ex-post mitigation strategies. The results show that the most effective strategy is to slaughter and not to vaccinate. We conclude that analyzing the supply chain is important in understanding how markets behave.

Page generated in 0.026 seconds