Thèses sur le sujet « Compression set »

Two novel methods to reduce the number of random test patterns required to fully test a circuit are proposed in this thesis. In the concept of correlated random patterns, reductions in a circuit's random pattern test length are achieved by taking advantage of correlations measured between values applied at different input positions in a complete deterministic test set. Instead of being generated independently, correlated inputs have their random values generated from a common source with each input's value then individually biased at a rate necessary to match the measured correlation. In the concept of cube-contained random patterns, reductions in random pattern test lengths are achieved by the successive assignment of temporarily fixed values to selected inputs during the random pattern generation process.
The concepts of correlated and cube-contained random patterns can be viewed as methods to compress a deterministic test set into a small amount of information which is then used to control the generation of a superset of the deterministic test set. The goal is to make this superset as small as possible while maintaining its containment of the original test set. The two concepts are meant to be used in either a Built-In Self-Test (BIST) environment or with an external tester when the storage requirements of a deterministic test are too large.
Experimental results show that both correlated and cube-contained random patterns can achieve 100% fault coverage of synthesized circuits using orders or magnitude less patterns than when equiprobable random patterns are used.

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Multilevel military communications security can be implemented with the notion of masterkeys. Naval message traffic is transmitted with restricted character set and optionally files are compressed. Both character translation and data compression can be used as add-on data encryption. A masterkey is constructed from a set of service keys from which masterkey is allowed to access. This thesis presents the principles of multilevel security with restricted character translation, data compression, and masterkey implementation.

This thesis studies the generalization behavior of algorithms in Sample Compression Settings. It extends the study of the Sample Compression framework to derive data-dependent bounds that give tighter guarantees to the algorithms where data-independent bounds such as the VC bounds are not applicable. It also studies the interplay between sparsity and the separating margin, of the classifier and shows how new compression based data-dependent bounds can be obtained that can exploit these two quantities explicitly. These bounds not only provide tight generalization guarantees but by themselves present optimization problems for learning leading to novel learning algorithms. This thesis studies the algorithms based on learning conjunctions or disjunctions of data-dependent Boolean features. With the Set Covering Machine (SCM) as its basis, the thesis shows how novel learning algorithms can be designed in compression settings that can perform a non-trivial margin-sparsity trade-off to yield better classifiers. Moreover, the thesis also shows how feature-selection can be integrated with the learning process in these settings yielding algorithms that not only perform successful feature selection but also have provable theoretical guarantees. In particular, the thesis proposes two novel learning algorithms. The first algorithm is for the SCM with data-dependent half-spaces along with a tight compression bound that can successfully perform model selection. The second algorithm aims at learning conjunctions of features called data-dependent Rays to classify gene expression data from DNA microarrays. The thesis shows how a PAC-Bayes approach to learning Rays' conjunctions can perform a non-trivial margin-sparsity trade-off to achieve classifiers that not only have provable theoretical guarantees but also utilize a significantly small number of attributes unlike traditional feature selection algorithms. This thesis also proposes two new formulations for the classical SCM algorithm with data-dependent balls aimed at performing margin-sparsity trade-off by utilizing Occam's Razor and PAC-Bayes principles respectively. The thesis shows how such approaches yield more general classifiers with tight risk bounds that can potentially guide the model selection process.

With rapid development in semiconductor technology, today's large and complex integrated circuits require a large amount of test data to achieve desired test coverage. Test cost, which is proportional to the size of the test set, can be reduced by generating a small number of highly effective test patterns. Automatic Test Pattern Generators (ATPGs) generate effective deterministic test patterns for different fault models and can achieve high test coverage. To reduce ATPG-produced test set size, design for test (DFT) methods can be used to further improve the ATPG process and apply generated test patterns in more efficient ways. The first part of this dissertation introduces a test point insertion (TPI) technique that reduces the test pattern counts and test data volume of a design by adding additional hardware called control points. These dedicated control points are inserted at internal nodes of the design to resolve large internal conflicts during ATPG. Therefore, more faults can be detected by a single test pattern. To minimize silicon area needed to implement these control points, we propose a method that reuses some existing functional flip-flops as drivers of the control points, instead of inserting dedicated flip-flops for the control points. Experimental results on industrial designs indicate that the proposed technique can achieve significant test pattern reductions, similar to the control points using dedicated flip-flops. The second part of this dissertation proposes a staggered ATPG scheme that produces deterministic test-per-clock-based staggered test patterns by using dedicated compactor scan chains to capture additional test responses during scan shift cycles that are used for regular scan cells to completely load each test pattern. These compactor scan chains are formed by dedicated capture-per-cycle observation test points inserted at suitable locations of the design. By leveraging this new scan infrastructure, more compacted test patterns can be generated, and more faults can also be systematically detected during the simulation process, thus reducing the overall test pattern count. To meet the stringent test requirements for in-system test (especially for automotive test), a built-in self-test (BIST) approach, called Stellar BIST, is introduced in the last part of this dissertation. Stellar BIST employs a dedicated BIST infrastructure with additional on-system memory to store some parent test patterns (seeds). Derivative test patterns can be obtained by complementing selected bits of corresponding parent patterns through an on-chip Stellar BIST controller. A dedicated ATPG process is also proposed for generating a minimal set of test patterns that need to be stored and their effective derivative patterns that require short test application time. Furthermore, the proposed scheme can provide flexible trade-offs between stored test data volume and test application time.

Ce travail porte sur la simulation numérique et la modélisation du comportement thermo-mécanique des matériaux composites renforcés par des fibres. Spécifiquement les matériaux SMC (Sheet Moulding Compound) sont utilisés dans le processus de moulage par compression pour construire des pièces automobiles de haute performance. Ce travail est divisé en quatre chapitres, décrivant tout d’abord un modèle thermo-mécanique entièrement couplé pour les matériaux SMC standards et innovants à haute concentration en fibres (> 25% en volume). Le SMC est traité comme un mélange incompressible de fibre et de résine complété éventuellement par une phase de porosité compressible. Son anisotropie est modélisée au moyen de tenseurs structurels. La cinétique de réaction et de consolidation de la pièce est également modélisée et étudiée. Les données expérimentales mécaniques et thermiques enregistrées sur des échantillons de matériaux SMC sont comparées au modèle et à la solution numérique fournie par ce travail. D’un point de vue numérique, nous utilisons la méthode des domaines immergées o`u chaque phase est distinguée par une fonction distance signée. Nous décrivons le procédé de moulage par compression en proposant une résolution compressible anisotrope unifiée capable de décrire la transition compressible / incompressible du matériau SMC sous déformation. Cela permet de décrire la réponse mécanique du SMC et de prédire localement la consolidation (durcissement) de la pièce le long du cycle thermique
This work deals with the numerical simulation and modeling of thermomechanical analysis of fiber reinforcedcomposites materials. Specifically for SMC (Sheet Molding Compound) materials that are used in compression molding processes to build automotive high performance parts. The work is divided into fourchapters, firstly describing a fully coupled thermo-mechanical model for standard SMC materials and for innovative SMC with high fiber concentration (> 25% in volume). The SMC is treated as an incompressible mixtureof fibers and paste complemented by a compressible porosity phase. Its anisotropy is modeled by means of structural tensors. Kinetic of reaction and consolidation of the part is also modeled and studied. Mechanicaland thermal experimental data recorded on samples of SMC materials are compared to the model and numerical solution provided in this work. A numerical framework, we use the immersed boundary method and the level set method. We describe the compression molding process by proposing an unified anisotropic compressible resolution able to describe the transition between compressible/ incompressible of SMC materials under deformation. We are able to describe the mechanical response of the SMC and to predict locally the consolidation (curing) of thepart throughout the thermal cycle

L’objectif de ces travaux de thèse est de développer un nouveau matériau pour des applications d’étanchéité dans l’industrie automobile. Pour cela, ce dernier doit présenter à la fois de bonnes propriétés de recouvrance élastique en compression (test de DRC) et une bonne mise en œuvre, permettant le recyclage. Pour cela différentes voies de réticulation ont été étudiées. Nous avons commencé par étudier une réticulation ionique, et son association a une réticulation par voie radicalaire sur un EPDM-g-AM. Ce système a par la suite été appliqué à des mélanges plus complexes, de type formulation industrielle. Dans un deuxième temps nous avons étudié la réticulation par voie alkoxysilane (en se basant sur les réactions d’hydrolyse/condensation des alkoxysilanes) d’un mélange SEBS/SBS. Une nouvelle fois ce type de réticulation a été couplé à une réticulation radicalaire. Les résultats étant prometteurs nous avons finalement transposé cette étude à une échelle plus importante en étudiant ce type de formulation en extrusion bi-vis
The objective of this thesis work is to develop a new material for sealing applications in the automotive industry. For this, it must have both good elastic recovery properties in compression (compression set experiment) and good processability, allowing recycling. To achieve this goal, different crosslinking pathways have been studied. We started by studying an ionic crosslinking, and its combination with a free radical crosslinking on an EPDM-g-AM. This system was subsequently applied to more complex blends, based on an industrial formulation. Secondly, we studied the crosslinking by alkoxysilane way (based on the hydrolysis/condensation reactions of alkoxysilane) on a SEBS/SBS blend. Once again, this type of crosslinking was coupled with radical crosslinking. The results being promising, we finally transposed these results on a larger scale by studying this type of formulations in twin screw extruder

A new fast and progressive set-partitioning image compression parallel algorithm with Region Of Interest (ROI) which outputs an embedded bit oriented rate-distortion optimized stream and addresses very low bit rate compression is presented.User defined variable packet sizes make it suitable for the implementation of any communications protocols, either underwater or in any other scenario, while remaining competitive with current state-of-the-art compressors at higher bit rates.A parallel algorithm for the Discrete Wavelet Transform (DWT) based on the lifting scheme is also presented and it is shown to be optimal in the sense that no other implementation may be faster if memory saturation is achieved.The best ordering for the significant and refinement bits of the transform coefficients is derived, using the Mean Squared Error (MSE) as the error measure, by fitting a Probability Density Function (PDF) to the transform coefficients and weighting the error for each range of coefficients by its respective DWT subband gain.A general scheme for Region Of Interest (ROI), including a non-linear scaling ROI, is presented in which the lower bitplanes of the foreground coefficients are delayed in exchange for better background reconstruction, achieving a more effective blending of foreground and background information.Finally, an implementation for both 32-bit and 64-bit ARM and x86 architectures was validated in an actual wireless underwater robotic teleoperation context.
Se presenta un nuevo algoritmo rápido y progresivo de compresión de imagen con Region De Interés (ROI) que emite un flujo optimizado de distorsión y trata una compresión de tasa de bits muy baja. Los tamaños de paquete variables definidos por el usuario lo hacen adecuado para el implementación de cualquier protocolo de comunicación, ya sea bajo el agua o en cualquier otro escenario, sin dejar de ser competitivo con los actuales compresores de última generación a mayores tasas de bits. Un algoritmo paralelo para la Transformada Wavelet Discreta (DWT) basado en el esquema de lifting es también presentado y se muestra como óptimo en el sentido de que ninguna otra implementación puede ser más rápida si se logra la saturación de la memoria. Se obtiene el mejor orden para los bits significativos y de refinamiento de los coeficientes de transformación, usando el Error Cuadrático Medio (MSE), al ajustar una función de densidad de probabilidad (PDF) a los coeficientes de transformación y ponderar el error para cada rango de coeficientes por su respectiva ganancia de subbanda DWT. Se presenta un esquema general para la Región de Interés (ROI), incluyendo un ROI de escalado no lineal, en el cual los planos de bit más bajos de los coeficientes de primer plano se retrasan a cambio de una mejor reconstrucción de fondo, logrando una efectiva combinación de información de fondo y de frente. Finalmente, se validó una implementación para las arquitecturas ARM y x86 de 32 bits y de 64 bits en un contexto de teleoperación robótica bajo el agua real.

L'Analyse Power Graph est une technique de compression sans perte de graphe visant à réduire la complexité visuelle d'un graphe. Le processus consiste à détecter des motifs, les cliques et les bicliques, qui permettent d'établir des groupes de nœuds organisés hiérarchiquement, des groupes d'arcs, et finalement un graphe réduit à ces groupes. Cette thèse propose tout d'abord la formalisation de l'espace de recherche de l'Analyse Power Graph, en utilisant l'Analyse de Concepts Formels comme base théorique pour exprimer le processus de compression. Le traitement indépendant de deux motifs présente des difficultés et nous proposons une notion unificatrice, les concepts triplets, qui conduiront à un motif unique plus général pour la compression. L'Analyse Power Graph et la nouvelle approche ont été implémentés dans un formalisme logique de Programmation par Ensembles Réponses (ASP), et nous présentons quelques applications en bioinformatique pour les deux approches. La thèse se clôt sur la présentation d'un environnement de visualisation et de spécification de haut-niveau en théorie des graphes
Power Graph Analysis is a lossless graph compression method aiming at reducing the visual complexity of a graph. The process is to detect motifs, cliques and bicliques, which enables the hierarchical clustering of nodes, the grouping of edges, and ultimately a graph reduced to these groups. This thesis exposes first the formalization of the Power Graph Analysis search space, using Formal Concept Analysis as a theoretical ground to express the compression process. Because the independent treatment of two motifs presents some caveats, we propose a unification framework, triplet concepts, which encode a more general motif for compression. Both Power Graph Analysis and the new approach have been implemented in Answer Set Programming (ASP), a logical formalism, and we present some applications in bioinformatics of these two approaches. This thesis ends on the presentation of an high-level specification and visualization environment for graph theory

Densification is a well-known method for improving the mechanical properties of wood. In the present study, unmodified and furfurylated wood samples were densified and submitted to cyclic water storage tests and cyclic alternating climate tests. Swelling coefficients and spring-back data were determined for the evaluation of the quality of densification. The study shows that results depend on the test method applied. Simple water storage tests do not reflect the behavior of densified wood in the high humidity range. The spring-back data of unmodified samples are more influenced by the testing method than those of the furfurylated ones.

Les thermoplastiques vulcanisés (TPV) sont des mélanges de polymères présentant à la fois des propriétés d'élasticité et de mise en œuvre et en forme. L'objectif de cette thèse est d'étudier les TPV à base d’un système PP/EPDM malgré la complexité de leurs formulations et de comprendre les mécanismes gouvernant la propriété de recouvrance élastique. La première partie de ce travail s'est concentrée sur l'influence de la chimie de réticulation sur les mécanismes de relaxation aux temps longs des réseaux élastomères réticulés. Il a été constaté que la réticulation radicalaire à partir de la décomposition thermique d’un peroxyde menait à une meilleure recouvrance élastique qu’avec la réticulation avec une résine phénolique. Cependant, la chimie de la réticulation n'est pas le paramètre de premier ordre qui influence cette propriété en ce qui concerne les TPV. En effet, elle dépend surtout de la formulation et du ratio thermoplastique/élastomère, ainsi, leurs influences sur les morphologies finales et sur la déformation rémanente en compression ont été étudiées dans une seconde partie. De plus, l'influence des charges inorganiques a également été étudiée dans les systèmes élastomères avec l'ajout de noir de carbone ou de silice ou dans les systèmes TPV avec l'ajout de noir de carbone. Il a été démontré que l'ajout de noir de carbone dans les systèmes réticulés au peroxyde est bénéfique et améliore les propriétés mécaniques : déformation rémanente après compression et comportement en traction (module d’Young, allongement à la rupture). En effet, la densité de réticulation et la compatibilité entre les polymères ont été améliorées. Enfin, une méthode RMN à bas champ a été utilisée pour l’étude de ces systèmes, notamment avec l'utilisation de la séquence Double Quanta (DQ) qui donne accès aux variations des mobilités moléculaires dans les matériaux avec la mesure du couplage dipolaire résiduel
Thermoplastics vulcanizates (TPVs) are polymer blends with interesting elasticity and processability properties. The objective of this thesis was to study PP/EPDM TPV despite the complexity of their formulations and to understand what influences the elastic recovery property. The first part of this work was focused on the influence of crosslinking chemistry and its statistics on the long-time relaxation mechanisms of crosslinked elastomeric networks. It was found that radical peroxide crosslinking provides better recovery elasticity than phenolic resin one. However, crosslinking chemistry has been seen to not be the first-order parameter that influences this property for TPV. It depends mostly on the formulation and the thermoplastic/elastomer ratio, their influence on the final morphology and compression set have been then studied in a second part. Moreover, the influence of inorganic fillers was also studied in elastomeric systems with the addition of CB or silica or in TPV systems with the addition of CB. It has been seen that the addition of CB in a system crosslinked with peroxides is beneficial for the improvement in mechanical properties: compression set or tensile test. Indeed, the crosslinking density and the compatibility between polymers were improved. Finally, a low-field NMR method has been applied to these systems, in particular with the use of the Double Quanta (DQ) sequence which gives access to the variations of molecular mobilities in the materials with the measurement of a residual dipolar coupling

Cette thèse porte sur le développement d’un moyen d’essai mécanique permettant de caractériser l’effet de la pression partielle d’oxygène sur le comportement mécanique des oxydes sous-stoechiométriques de type pérovskite utilisé pour leur propriété de semi-perméation. Pour étudier ces matériaux, un nouveau protocole expérimental a été développé, ainsi qu’une méthode numérique de dépouillement ad hoc. Les essais de compression diamétrale cyclique et fluage par compression diamétrale mis en place sont réalisés dans un four d’essais mécaniques à étanchéité renforcée permettant de maitriser l’atmosphère gazeuse dans la zone utile pendant l’essai. Le four, conçu pour ces essais, permet la réalisation de mesures optiques en temps réels. Pour l’identification des paramètres matériaux, une nouvelle routine nommée DigImCo.v2 a été développée. Celle-ci couple les techniques de corrélation d’images numérique (CIN) et la méthode d’identification par analyse inverse à travers la simulation numérique des essais et les méthodes d’optimisation. L’algorithme d’optimisation proposée découle de celui de Levenberg-Marquardt modifié et la loi de fluage implémentée dans le logiciel de simulation éléments finis est une loi de type Norton. Les résultats des essais montrent une faible influence de la pression partielle d’oxygène sur les matériaux étudiés, qui présentent également des déformations de fluage négligeables comparativement aux matériaux de la littérature
This thesis deals with the development of mechanical set up that allows characterizing the oxygen partial pressure effect on the mechanical behavior of sub-stoichiometric perovskites oxides, used due to their potential oxygen semi-permeation properties. In order to study these materials, a new experimental set up and a new post-process routine are developed. Diametric compression tests and creep by diametric compression are conducted in an original mechanical test furnace with reinforced sealing and controlled atmospheres. The tests are instrumented by optical measurements. In order to control the oxygen partial pressure in the test zone, and to study its real influence on mechanical properties, an oxygen sensor is monitored to the device. To analyze experiences, a new post-process routine called DigImCo.v2 is developed that permits to identify material parameters. This approach combine Digital Image Correlation method and an inverse identification method. The optimization technic is based on Levenberg-Marquardt module and the numeric model simulation of the tests are performed on Abaqus software. For the creep parameters identification, Norton creep model is simulated in Abaqus. Tests results reflect the relatively weak influence of oxygen partial pressure on studies materials, which exhibit negligible creep strains compared to literature

The objectives of the thesis were to find the mechanisms that govern compression failures in paperboard and to find the link between manufacturing process and paperboard properties. The thesis also investigates two different test methods and evaluates how suitable they are for paperboard grades. The materials are several commercial board grades and a set of hand-formed dynamic sheets that are made to mimic the construction of commercial paperboard. The method consists of mounting a stereomicroscope on a short-span compression tester and recording the compression failure on video, long-span compression testing and standard properties testing. The observed failure modes of paperboard under compression were classified into four categories depending on the appearance of the failures. Initiation of failure takes place where the structure is weakest and fiber buckling happens after the initiation, which consists of breaking of fiber-fiber bonds or fiber wall delamination. The compression strength is correlated to density and operations and raw materials that increase the density also increases the compression strength. Short-span compression and Long-span compression are not suitable for testing all kinds of papers; the clamps in short-span give bulky specimens an initial geometrical shape that can affect the given value of compression strength. Long-span compression is only suitable for a limited range of papers, one problem with too thin papers are low wavelength buckling.

Deployment of a large box structure in many sea states has been investigated. Two deployment methods are compared; crane installation over the side and through moonpool installation. The structure is 12 [m] long, 6 [m] wide and 12 [m] high with a mass of 250 [t]. Normand Subsea is used as installation vessel. Both JONSWAP and Torsethaugen wave spectra are used for crane lowering while only JONSWAP is used for moonpool installation.Splash zone lowering is seen as the most critical stage of the installation because hydrodynamic forces are largest at the surface. Hydrodynamic uplift is assumed limiting for the deployment, i.e “slack slings”. Slings are the lower part of the lift rigging. The operation limit is that dynamic uplift should not exceed 90 % of the modules static weight. Forces in z-direction are hence most interesting. Minimum wire tension for the lowering is therefore calculated at two time instances; when the module bottom end is at mean water level and when the module is fully submerged with its top end 0.5 [m] below mean water level. These time instances are referred to as time instance 1 and 2 in the report respectively. Design significant wave heights, Hs, are taken from plots of minimum wire tension for different wave peak periods Tp and wave headings. Based on these design Hs values, which equals the operation limits, operability rosettes are plotted. It is seen that wave headings 90⁰ and 120⁰ are most critical with lowest operability for crane installation while wave heading 90⁰ is worst for moonpool deployment.The lowest design Hs for all Tp values considering wave headings 0⁰ ±30⁰ is used as overall operation limit for deployment when weather window statistics are computed. Time instance 1 is worst for crane deployment with resulting forecasted weather operational criterion Hs=2.8 [m]. Time instance 2 is worst for moonpool deployment with forecasted operational criterion Hs=2.5 [m] and Tp ≥ 13.0 [s]. Reference time for deployment, hence the time needed from the weather forecast is issued to the module is landed on the seabed, is 6 hours. Based on reference time and forecasted operation limits weather window statistics are estimated.Moonpool deployment annual operability is 7.24 days, hence 2.0 % of the year, and can naturally not be used. Crane deployment annual operability is 213.22 days, 58.4 % of the year. This is much better but still not very good as it is theoretically desirable to be able to install the module any day year round.

This dissertation deals with customised image analysis tools in cancer research. In the field of biomedical sciences, mathematical imaging has become crucial in order to account for advancements in technical equipment and data storage by sound mathematical methods that can process and analyse imaging data in an automated way. This thesis contributes to the development of such mathematically sound imaging models in four ways: (i) automated cell segmentation and tracking. In cancer drug development, time-lapse light microscopy experiments are conducted for performance validation. The aim is to monitor behaviour of cells in cultures that have previously been treated with chemotherapy drugs, since atypical duration and outcome of mitosis, the process of cell division, can be an indicator of successfully working drugs. As an imaging modality we focus on phase contrast microscopy, hence avoiding phototoxicity and influence on cell behaviour. As a drawback, the common halo- and shade-off effect impede image analysis. We present a novel workflow uniting both automated mitotic cell detection with the Hough transform and subsequent cell tracking by a tailor-made level-set method in order to obtain statistics on length of mitosis and cell fates. The proposed image analysis pipeline is deployed in a MATLAB software package called MitosisAnalyser. For the detection of mitotic cells we use the circular Hough transform. This concept is investigated further in the framework of image regularisation in the general context of imaging inverse problems, in which circular objects should be enhanced, (ii) exploiting sparsity of first-order derivatives in combination with the linear circular Hough transform operation. Furthermore, (iii) we present a new unified higher-order derivative-type regularisation functional enforcing sparsity of a vector field related to an image to be reconstructed using curl, divergence and shear operators. The model is able to interpolate between well-known regularisers such as total generalised variation and infimal convolution total variation. Finally, (iv) we demonstrate how we can learn sparsity promoting parametrised regularisers via quotient minimisation, which can be motivated by generalised Eigenproblems. Learning approaches have recently become very popular in the field of inverse problems. However, the majority aims at fitting models to favourable training data, whereas we incorporate knowledge about both fit and misfit data. We present results resembling behaviour of well-established derivative-based sparse regularisers, introduce novel families of non-derivative-based regularisers and extend this framework to classification problems.

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The usage of mammographic image databases in digital form and the practice of telemedicine require to store and to transmit large amounts of data. The image digitization from a single mammographic exam with appropriate resolution can take up to 120MB of space in disk, which becomes even more critical when considering the large number of exams per day on a clinic. Thus, efficient data compression techniques are needed to reduce storage and transmission costs. This document describes the development of a high-performance lossless compressor based on Prediction by Partial Matching (PPM) algorithm with modules for segmentation, mapping, gray code, bit planes decomposition and move-to-front transform, for mammographic image compression. The compressor developed was efficient in both compression ratio and processing time, and compresses 27MB images in about 13 seconds with an average compression ratio of 5,39.
A utilização de bancos de dados de imagens mamográficas em formato digital e as práticas de telemedicina exigem que se armazene e transmita grandes quantidades de dados. A digitalização das quatro imagens de um único exame mamográfico com resolução adequada pode ocupar até 120MB de espaço em disco. Esta quantidade de dados leva a uma situação ainda mais crítica ao considerar-se o grande número de exames diários efetuados rotineiramente em uma clínica. Assim, técnicas eficientes de compressão de dados são necessárias para reduzir os custos relativos ao armazenamento e à transmissão destas imagens. O presente trabalho descreve o desenvolvimento de um sistema de alto desempenho para compressão sem perdas de imagens mamográficas baseado no algoritmo Prediction by Partial Matching (PPM), em conjunto com módulos para segmentação, mapeamento, codificação com Código Gray, decomposição em planos de bits e transformada move-to-front (MTF). O sistema desenvolvido mostrou-se eficiente tanto no que tange à razão de compressão quanto ao tempo de processamento, comprimindo imagens de 27MB em aproximadamente 13 segundos com razão de compressão média de 5,39.

Accelerating and mineral admixtures, one of the major ingredients in concrete, are primarily used to modify the properties of both fresh and hardened concrete. Within the scope of this thesis, there were four types of cements having almost identical fineness. The mixes were prepared by using natural pozzolan, blast furnace slag and limestone conforming to TS EN 197-1 and two types of accelerating admixtures, namely triethanolamine (TEA) and calcium formate (CF). The effect of set accelerating admixtures with different cement types on the setting time, water demand and compressive strength has been analyzed by an experimental study in accordance with relevant ASTM standards. Finally, it has been observed that the amount of the accelerating admixtures used is suitable because of their effects on the water demand, setting and strength. Due to the density difference of mineral admixtures and clinker, the normal consistency and 110% flow water content should be considered on a volumetric basis. The effectiveness of the accelerating admixtures on the normal consistency water, 110% flow water content and setting time depends on the type and amount of mineral admixtures. The increase caused by CF in the normal consistency and 110% flow water content is higher than that by TEA. The accelerating effect of TEA and CF on the setting times is more significant for cements incorporating 6% mineral admixture. The effects of accelerating admixtures on the compressive strength change with specimen age, type and amount of mineral admixtures. Generally, for all cement types, early age compressive strengths increase with the increase of TEA, however long term strengths increase by increasing CF.

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The current wireless networks development scenario indicates that mobile VoIP applications are increasing their appeal among consumers, which creates an increasing demand for bandwidth consuption. However, bandwidth availability for VoIP applications is restricted by phisical and regulatory means. Header compression algorithms are one of the most used bandwidth optimization techniques for VoIP applications in wireless networks. This dissertation presents a performance evaluation of cooperative header compression algoritms for VoIP applications in wireless networks. The results indicate that the use of the single-channel cooperative approach leads to excelent results in terms of bandwidth optimization alied with robust context update. Also, the results indicate that the multi-channel cooperative approach has serious issues regarding parallel asyncrhonous VoIP connections.
O cenário atual do desenvolvimento das redes sem fio indica que o apelo por aplicações VoIP móveis está crescendo entre os consumidores, o que gera uma demanda cada vez maior de consumo de largura de banda. No entanto, a disponibilidade de largura de banda para aplicações VoIP é limitada tanto pelo meio físico quanto por regulamentações governamentais. O uso de algoritmos de compressão de cabeçalho é uma das técnicas mais usadas para otimização de largura de banda para aplicações VoIP em redes sem fio. Esta dissertação apresenta uma avaliação de desempenho de algoritmos de compressão de cabeçalhos cooperativos para aplicações VoIP em redes sem fio. Os resultados indicam que a utilização do algoritmo cooperativo mono-canal leva a excelentes resultados em termos de otimização de largura de banda com a manutenção das atualizações de contexto. Além disso, os resultados indicam que o uso do algoritmo cooperativo multi-canal possui sérias restrições quando utilizado em conjunto com conexões VoIP paralelas e assíncronas.

Le phénomène de la décomposition de certaines orientations de cristaux cfc en laminage est étudié par des expériences de compression plane sur monocristaux, en parallèle avec une modélisation théorique originale. La déformation hétérogène de cristaux d'aluminium d'orientation (001)[kho] est associée a de grandes rotations cristallines de sens opposes autour de DT. La cinétique de décomposition est en accord avec une modélisation du type Taylor relâché, tandis que la répartition spatiale des bandes de déformation s'explique par une analyse fine de leurs incompatibilités de déformation plastique. Afin d'étudier l'influence de la température sur la déformation de cristaux à chaud, un nouveau dispositif de compression plane bi-encastrée a été mis au point (Tmax 450c, max 1. 2). Des essais préliminaires laissent entrevoir la possibilité d'une stabilisation de l'orientation cube a des températures proches de 400c. Les mécanismes de recristallisation de monocristaux déformes d'aluminium sont caractérisés par microdiffraction au MEB (ECP et EBSD). Une attention particulière est portée à l'influence des bandes de transition -BT- dans les cristaux (001)[hko] après compression plane. En général, deux cas de présentent: (i) germination dans les BT avec une rotation du germe vers l'orientation cube, et (ii) germination dans la matrice des bandes de déformation avec plusieurs types de relations d'orientation (matrice, vers cube ou autour d'axes<111>). Les orientations des grains après recristallisation complète sont également déterminées et les désorientations caractérisées en termes du type de joint de grain (méthode CSL)
The phenomenon of the decomposition of certain guidelines in fcc crystals rolling is studied by compression experiments on single crystals flat, in parallel with an original theoretical modeling. The heterogeneous deformation of aluminum crystal orientation (001) Kho) is associated with large crystal rotations of opposite directions around DT. The decomposition kinetics are consistent with a Taylor-type models released, while the spatial distribution of deformation bands is explained by a detailed analysis of their plastic deformation incompatibilities. To study the influence of temperature on the hot deformation of crystals, a new compression device bi-recessed flat has been developed (tmax 450c, max 1. 2). Preliminary tests suggest the possibility of a stabilization of the cube orientation has around 400c temperatures. Recrystallization of deformed single crystal of aluminum mechanisms are characterized by SEM micro diffraction (EBSD and ECP). Particular attention is paid to the influence of transition -bt- bands in crystals (001) hko plane after compression. In general, two cases arise: (i) bt germination in a seed with the rotation towards the cube orientation, and (ii) sprouting in the matrix deformation bands with several types of orientation relationships (matrix, to cube or about axes <111>). The orientations of grains after complete recrystallization are also determined and disorientation characterized in terms of the type of grain boundary (method SCL)

Fundação do Amparo à Pesquisa do Estado do Amazonas (FAPEAM)
Nesta dissertação de mestrado é apresentada uma proposta de um método simples de compressão de dados sem perda para Redes de Sensores sem Fio (RSSF). Este método é baseado numa codificação Huffman convencional aplicada a um conjunto de amostras de parâmetros monitorados que possuam uma forte correlação temporal, fazendo com que seja gerado um dicionário Huffman a partir dessas probabilidades e que possam ser utilizadas em outros conjuntos de parâmetros de mesma característica. Os resultados de simulação usando temperatura e umidade relativa mostram que este método supera alguns dos mais populares mecanismos de compressão projetados especificamente para RSSF.
In this masters thesis we present a lightweight lossless data compression method for wireless sensor networks(WSN). This method is based on a conventional Huffman coding applied to a sample set of monitored parameters that have a strong temporal correlation, so that a Huffman dictionary is generated from these probabilities, and which may be used in other sets of parameters with same characteristic. Simulations results using temperature and relative humidity measurements show that the proposed method outperforms popular compression mechanisms designed specifically for wireless sensor networks.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2014.
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O superaquecimento do fluido refrigerante no processo de sucção reduz as eficiências volumétrica e isentrópica de compressores recíprocos usados em sistemas de refrigeração. A presente dissertação considera a modelação térmica de um compressor recíproco operando sem óleo lubrificante. O método de volumes finitos foi adotado para a solução da condução de calor nos componentes sólidos e do escoamento de fluido refrigerante no interior da carcaça. A fim de reduzir o custo computacional, o ciclo de compressão no interior do cilindro foi modelado com uma formulação integral transiente, mas de forma acoplada ao restante do domínio de solução. O modelo desenvolvido foi adotado para a previsão dos campos de velocidade e temperatura, bem como do fluxo de calor em diferentes regiões do compressor. Em termos da distribuição de temperatura, diferenças pontuais entre resultados numéricos e experimentais foram observadas para os sólidos e para o gás, sendo levantadas hipóteses para justificá-las. Apesar disso, o modelo forneceu previsões em boa concordância com as medições em quatro diferentes condições de operação, especialmente em relação ao superaquecimento do gás de sucção e a parâmetros de eficiência do compressor. Uma vez que não necessita de calibração experimental, o modelo desenvolvido é particularmente útil no projeto de compressores.

Abstract : Suction superheating acts to reduce the volumetric and isentropic efficiencies of small reciprocating compressors adopted for household refrigeration. This dissertation considers the thermal modeling of an oil-free linear compressor. The finite volume method was adopted for the solution of both the heat conduction in solids components and the flow of refrigerant inside the compressor shell. In order to reduce the computational cost, the compression cycle inside the cylinder was modeled via a transient lumped formulation, but in a coupled manner with the model for the remainder of the solution domain. The developed model was adopted to predict the velocity and temperature fields and heat flux in different regions of the compressor. In terms of temperature distribution, some difference between numerical and experimental results was observed in specific regions of solid components and gas. Nevertheless, the model presented was able to predict estimates in good agreement with measurements, especially for gas suction superheating and efficiency parameters, in four different operating conditions. The model does not require experimental calibration, being particularly useful in compressor design.

The aim of this thesis was to investigate the difference between containerboard materials strength and stiffness properties in tension and compression, how the mechanisms behind compressive and tensile properties are affected by the relative humidity of the ambient air and how the relative humidity affects the compressive response of the fibre network. These properties are used to predict the lifetime performance of corrugated boxes and to prevent early collapses of the boxes and thereby waste or harm of the transported goods inside. The work also discusses the methods used to evaluate the different properties and how reliable the results are. The experimental part includes testing of linerboard and fluting materials from both virgin and recycled fibres, which have been conditioned at 50% and 90% relative humidity. The compression tests were filmed to evaluate if different compression failure modes can be related to the strength and stiffness of the material. The results indicated that the compressive strength and stiffness differ from the strength and stiffness values in tension at 90% relative humidity. Compressive strength is lower in both 50% and 90% relative humidity compared with the tensile strength. However, the compression stiffness shows a higher value than the tensile stiffness at 90% relative humidity. The study of the method for evaluating the compressive behaviour of the paper does not present a complete picture on what type of failure the paper actually experience.

The increasing development of mobile computing technologies has allowed users to access the Internet any time and anywhere. However, as the resources of mobile devices are scarcer than their counterparts in wired network, there is the need to adapt data documents in order to provide efficient access to applications and services in wireless environments. In this work, it is proposed a model which predicts how and when a file should be compressed before its transmission over a wireless channel, aiming to minimize the impact on energy consumption and to improve response time. Experiments in real scenarios and simulations using ns2 simulator with both IEEE 802.11 and Bluetooth technologies prove the efficiency of this model when compared with other simplistic approaches adopted in literature
O atual desenvolvimento das diversas tecnologias da computação móvel permite a um usuário acessar a Internet de qualquer lugar e a qualquer instante. Entretanto, para prover um acesso eficiente nesse ambiente, necessitamos de algum processo de adaptação do conteúdo da Web, uma vez que os recursos dos dispositivos móveis são inerentemente escassos. Nesse trabalho propomos um modelo para adaptação de conteúdo HTML que prevê, dinamicamente, quando um arquivo deve ser comprimido antes de sua transmissão. Nossos experimentos e simulações com os ambientes Bluetooth e IEEE 802.11 comprovam a eficácia e a factibilidade desse modelo quando comparado às técnicas atuais de adaptação por compressão.

Nella seguente tesi si descrive e si analizza un set-up sperimentale innovativo per le prove a taglio e compressione su pannelli murari. In questo elaborato si andranno a dimensionare alcuni elementi del set-up di prova in modo tale da ricreare le condizioni di vincolo incastro/incastro scorrevole, che permettono di simulare il comportamento reale della struttura. L’applicazione di queste forze controllata e calibrata in ogni istante di tempo, questo modo di procedere garantisce il rispetto delle condizioni di vincolo imposte. Inoltre uno studio accurato della strumentazione permette di rilevare le fessure che potrebbero manifestarsi in seguito alla rottura a taglio della muratura o per effetto rocking.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In the resonant linear compressor the piston is drive by a linear actuator and a resonant mechanical spring directly in the reciprocating motion, this is a mass spring resonant system, eliminating bearing and crank of the conventional reciprocating compressors, and the friction loss has a significant reduction. The maximum displacement of the piston is regulating by the equilibration between the power supply by the actuator and the power transfer to the gas compression process. This type of the compressor is design to work at the resonant frequency of the mass spring system, in this condition the efficiency is maximum. Then the control must drive the linear actuator in the maximum displacement of the piston and adjust the drive frequency at the system resonant frequency. For enable of this process is necessary that piston position is known with precision, however the installation of a sensor have same difficulty, since the refrigeration compressor is hermetic system, and it have high pressure and temperature, with wide range of variation. This work develop the implementation of a full order linear observer to estimate the displacement and the velocity of the piston of the resonant linear compressor, and a control system able to drive the compressor in the maximum piston displacement and in the resonant frequency, and only measured a current of the linear actuator, without sensor inside de compressor. For this a nonlinear model of the compressor and a linear model with variable coefficients for the observer are develop, also a simulator of the system is develop, where the compressor model is controlled by the displacement and the velocity signals calculate by observer, demonstrated the feasibility of the proposed technique in the present work.
Nos compressores lineares ressonantes o pistão é acionado por um atuador linear e molas diretamente no sentido do seu movimento alternativo, formando um sistema massa-mola ressonante, eliminando assim os mancais mecânicos e o sistema biela e manivela dos compressores convencionais, reduzindo de forma significativa as perdas por atrito. A amplitude do deslocamento do pistão é regulada pelo equilíbrio da potência fornecida pelo atuador e a potência transferida para o processo de compressão do gás. Estes compressores são projetados para funcionar na frequência de ressonância do sistema massa-mola, nesta condição a eficiência do sistema é máxima. Assim, o controle deve acionar o atuador linear na máxima amplitude de deslocamento do pistão e ajustar a frequência de acionamento na frequência de ressonância do sistema. Para viabilizar este processo é necessário que o curso do pistão seja conhecido com precisão, porém a instalação de um sensor apresenta dificuldades, pois os compressores de refrigeração são herméticos e estão sujeitos a pressões e temperaturas elevadas e com grande faixa de variação. Este trabalho propõe a implementação de um observador de estados de ordem plena, para estimar o deslocamento e a velocidade do pistão do compressor linear ressonante, e um sistema de controle capaz de acionar o compressor no deslocamento máximo e na frequência de ressonância, medindo somente a corrente no atuador linear, sem a necessidade de sensores instalados dentro do compressor. Para isto desenvolve-se um modelo não linear do compressor e um modelo linear equivalente de coeficientes variáveis para o projeto do observador, também é desenvolvido um simulador do sistema, onde o modelo do compressor é controlado pelos sinais de deslocamento e velocidade calculados pelo observador, demonstrando a viabilidade da técnica proposta no presente trabalho.

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FADESP - Fundação de Amparo e Desenvolvimento da Pesquisa
Nos últimos anos o mundo tem visto uma demanda crescente por serviços móveis de alta capacidade e baixo custo, isto tem forçado as tecnologias da rede de acesso móvel a serem repensadas. Entre as diferentes arquiteturas propostas na literatura, uma que ganhou bastante atenção é a centralização dos recursos da rede. Essa estratégia propõe compartilhar os recursos da rede através da centralização do processamento em banda-base, e como resultado reduzir o custo da rede. Apesar da centralização trazer vários benefícios, ela também aumenta a distancia entre o ponto onde os sinais são capturadas e o ponto onde são processados, o link que conecta esses dois pontos é chamado de fronthaul. Nesse cenário, as tecnologias de fronthaul existentes não são apropriadas para os requisitos de flexibilidade e custo esperados para a próxima geração de redes fronthaul, devido principalmente ao uso de links óticos dedicados. Uma solução para esses problemas é a utilização de Ethernet para transportar o trafego fronthaul, devido a sua onipresença, flexibilidade e baixo custo. Neste trabalho um testbed para fronthaul baseado em Ethernet ´e apresentado, juntamente com os detalhes de implementação e resultados de validação. Além disso, motivado pela limitação em banda existente no Ethernet, este trabalho apresenta a implementação em VHDL de um algoritmo de compressão de sinais LTE, avaliado em uma rede Ethernet real através do testbed. Os resultados obtidos indicam que é possível utilizar a infra-estruturar provida pela rede Ethernet no transporte de fronthaul. Por outro lado é necessário reduzir os requisitos exigidos pelo tráfego fronthaul. Através, por exemplo, da aplicação da compressão de sinais e de técnicas de sincronismo.
In recent years the world has seen an increasing demand for mobile services with high capacity and low cost. Such requirements forced the radio access technologies to be rethought. Among the different architectures proposed in literature, one that has got a lot of attention was the Centralized Radio Access Network (C-RAN). This strategy proposes to share the network resources through the centralization of the base-band processing and, as a result, reduce the network cost. Even though the centralization can bring several benefits, it also increases the distance between the point where the signal is captured and the point where it is processed. The link connecting both points is called fronthaul. In this scenario, the existing fronthaul technologies do not fit in the flexibility and cost requisites expected for the next generation mobile network, mainly due to the usage of dedicated optical links. One solution to these problems is the usage of Ethernet to transport fronthaul data, due to its ubiquitous presence, flexibility and low cost. In this work, a testbed for fronthaul based on Ethernet is presented, along with the implementation details and validation results. Also motivated by the Ethernet’s bandwidth limitation, this work presents the VHDL implementation of a compression technique for LTE signals, evaluated in real transport conditions with the testbed. The obtained results indicate that it is possible to utilize the Ethernet network infrastructure for fronthaul transport. Although, it is necessary to reduce the requirements of Fronthaul stream through, for example, the application of signal compression techniques and synchronization methods.

This work aims to increase our understanding of the nature of large scale features of sea ice from a dynamics point of view.Sea ice plays an important part in the exchange of heat and humidity between sea and air and thus is an important component of the climate system. Its physical presence also directly impacts the various forms of life such as diatoms, polar bears and humans alike.The dynamics of sea ice affect both weather and climate, through the large scale drift in the Arctic from the Siberian coast towards Fram Strait, through creation of cracks in the ice called leads or polynyas, and through ridging and other mechanical deformations of ice floes.In this work, we have focused on modelling of ridged ice for a number of reasons. Direct observations of the internal ice state is very difficult to perform and in general, observations of sea ice are either sparse or of limited information density. Ridged ice can be seen as the memory of high ice stress events, giving us a view on these highly dynamic events. Ridging is of major importance for the ice thickness distribution, as the thickest ice can only be formed through mechanical processes. Further, ridged ice is of direct interest for anyone conducting shipping through seasonal or perennial ice covered seas as it can form impenetrable barriers or in extreme even cases crush a ship caught within the ice pack. To this end, a multi-category sea ice model, the HELsinki Multi category Ice model (HELMI), was implemented into the Rossby Centre Ocean model (RCO). HELMI has explicit formulations for ridged and rafted ice, as well as sub-grid scale ice thickness distribution (a feature shared with other multi category models) and an ice strength based on energetics. These features give RCO better representation of sub-grid scale physics and gives us the possibility to study the deformed ice in detail. In paper I we look at the change in behaviour in the Arctic as the ice becomes more mobile, leading to a slight increase in modelled ridged ice volume in the central Arctic, despite a general trend of a decreasing ice cover.Paper II takes us to the Baltic Sea and the possibilities of modelling ridge ice concentration with a statistical model.In Paper III we investigate how the diminishing ice cover in future scenarios affects the biological activity in the Baltic Sea.Finally Paper IV investigates how the ice stress and the internal ice force can be interpreted in terms of ice compression on the ship scale.

At the time of the doctoral defence the following paper was unpublished and had a status as follows: Paper 4: Manuscript

La muratura è sicuramente uno dei materiali strutturali più antico e diffuso in Italia. È costituita da mattoni e malta, componenti che hanno proprietà molto diverse tra loro e per questo la muratura stessa viene considerata un materiale eterogeneo e anisotropo; pertanto, le analisi da eseguire per comprendere il suo comportamento nel complesso sono molto complicate. Oggigiorno, però, è possibile far ricorso a degli appositi modelli numerici che rappresentano una valida alternativa alle prove sperimentali e tra questi vi sono (Kurdo F. Abdulla, Lee S. Cunningham, Martin Gillie, 2017): il metodo agli elementi finiti (FEM), il metodo agli elementi discreti (DEM), l’analisi limite e il metodo degli elementi applicati (AEM). Infatti l’obiettivo di questo lavoro di tesi è comprendere che tipo di rottura avviene in un pannello murario di dimensioni reali sottoposto ad una prova di taglio-compressione tramite la modellazione agli elementi finiti di un innovativo set-up sperimentale grazie all’utilizzo del software Straus7. In particolare si andrà ad analizzare come i parametri meccanici della muratura influenzano l’attivazione del meccanismo di rottura permettendo, dunque, di cogliere i vari aspetti del suo comportamento.

Orientador : Yuzo Iano
Tese (doutorado) - Universidade Estadual de Campinas,Faculdade de Engenharia Eletrica e de Computação
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Resumo: Neste trabalho, apresenta-se um tutorial sobre a técnica de Codificação Aritmética Binária Adaptativa (CABA), onde a CABA é a base principal do padrão JBIG (¿Joint Bi-level Image Experts Group¿). O esforço é dedicado para o estudo e a implementação de quatro sub-blocos que fazem parte do padrão JBIG: sub-bloco ¿Redutor de Resolução¿, sub-bloco ¿Predição Típica¿, sub-bloco ¿Template Modelo¿ e sub-bloco ¿Codificador Aritmético Adaptativo¿. O presente trabalho tem como objetivo o desenvolvimento de protótipo software de ¿Codec¿ de CABA para imagens de escala de cinzas e imagens coloridas, tendo-se em vista a codificação sem perdas. Realizou-se a simulação de uma nova proposta usando-se método progressivo do padrão JBIG com o objetivo de se representar a informação de imagem em planos de bits e camadas de resolução. Essa proposta consiste em se transferir o modo progressivo para o decodificador do JBIG ao invés de usá-lo no codificador que é o procedimento comum. Isso permitirá o ganho desejado na taxa de compressão. Os resultados numéricos são apresentados e analisados
Abstract: In this work, a tutorial about an Adaptive Binary Arithmetic Coding technique (ABAC) is presented, where the ABAC is the principal base of the JBIG standard (¿Joint Bi-level Image Experts Group¿). The main effort is dedicated to the study and the implementation of four sub-blocks of the JBIG standard namely: sub-block ¿Resolution Reduction¿, sub-block ¿Typical Prediction¿, sub-block ¿Model Template¿ and sub-block ¿Adaptive Arithmetic Encoder¿. The main objective of this work is the development of a software prototype of Codec of ABAC for greyscale and colour images, with the aim to obtain a lossless coding. The simulation of a new proposal was realised using the progressive method of the JBIG standard with the objective of representing the image information in bit-planes and resolution layers. This proposal consists of transferring the progressive mode to the decoder of JBIG instead of using the common procedure. This would allow the desired gain in the compression ratio. The numerical results are presented and analysed.
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica

Nella tesi si è descritto un set-up innovativo per le prove di laboratorio di taglio-compressione e se ne è fatta una simulazione mediante il metodo agli elementi finiti al fine di effettuare analisi non lineari. Il modello utilizzato è stato calibrato usando come riferimento prove di laboratorio già effettuate al fine di verificarne la validità. Si è poi analizzato il comportamento del set-up di prova al variare dei principali parametri meccanici e geometrici: modulo elastico, resistenza a compressione e lunghezza di base del pannello oggetto della prova. Si sono inoltre effettuate analisi al variare della tensione di precarico iniziale e del processo di carico con cui vengono applicati i carichi verticali nel corso delle prove. Mediante questa tesi vengono fornite metodologie per l'organizzazione delle prove di taglio-compressione e risultati utili a comprendere le dinamiche di prova.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The amount of data generated and transmitted by satellites to ground stations is always growing. As the technology advances, space imaging systems, especially those present in Earth observing missions, use equipment of increasing resolutions. Hence, it is necessary to ensure that this great quantity of data arrives at their destination reliably. Among some techniques involved, data compression plays an important role to accomplish this requirement. A data compression system for this purpose must comply with some conditions, particularly regarding performance. In this context, hardware implementations based on prediction and Golomb-Rice coding has achieved excellent results considering hardware and compression performance in both lossless and lossy cases. This work proposes a digital hardware approach of a low complexity satellite image lossless compressor based on prediction and Golomb-Rice coding that is attuned to the balance between performance requirements and error propagation, a common issue in space systems environment that is enhanced by data compression. In order to validate and analyze the compressor, a functional verification and FPGA prototyping methodology were followed. Given an image set from Brazilian's National Institute for Space Research (INPE, in the Portuguese acronym), CBERS-2B satellite, its results in FPGA show that this compressor achieves average compression ratio of 3.4, comparable value to related works in this area, and throughput of 28 MPixel/s (224 Mbit/s). Taking advantage of images nature, its compression can be parallelized through simultaneous multi-cores compressors. For example, using 5 cores, this work is able to compress those images in a rate of 142 MPixel/s (1.1 Gbit/s). All these features make it useful and effective in a current remote sensing imaging system.
A quantidade de dados gerados e transmitidos pelos satélites para as estações na Terra é cada vez maiores. Com o passar do tempo e avanço da tecnologia, os sistemas de imageamento espaciais, particularmente as missões de observação da Terra, tem utilizado equipamentos com resoluções cada vez maiores. Por esse motivo, se faz necessário garantir que os dados cheguem ao destino de maneira confiável. Dentre algumas técnicas envolvidas, a compressão de dados é o meio mais viável de alcançar esse requisito. Um sistema de compressão de dados para esse fim deve obedecer algumas condições, principalmente quanto ao desempenho. Nesse contexto, implementações em hardware baseadas em predição e codificação de Golomb-Rice têm obtido excelentes resultados considerando desempenho do hardware e da compressão, tanto nos casos sem perdas como nos com perdas. O presente trabalho apresenta uma proposta de hardware digital de um compressor sem perdas para imagens de satélite baseado em predição e codificação Golomb-Rice que busca um balanceamento entre os requisitos de desempenho e a propagação de erros, um problema comum no âmbito de sistemas espaciais e que é potencializado no caso dos compressores de dados. Para validação e análise do compressor, é seguida uma metodologia de verificação funcional de hardware digital e o desenvolvimento de um protótipo em FPGA. Dado um conjunto de imagens do satélite CBERS-2B disponibilizadas pelo Instituto Nacional de Pesquisas Espaciais, os resultados obtidos em FPGA mostram que esse compressor alcança razão de compressão média de 3,4, valor comparável a trabalhos correlatos, e velocidade de 28 MPixel/s (224 Mbit/s). Considerando a natureza das imagens, a compressão pode ser paralelizada por meio de simultâneos núcleos compressores em uma abordagem multicore. Por exemplo, usando 5 núcleos, o sistema proposto é capaz de comprimir essas imagens em uma velocidade de 142 MPixel/s (1.1 Gbit/s). Todas essas características tornam-no útil e efetivo para a aplicação em um sistema moderno de imageamento para sensoriamento remoto.

Cement is the construction building material with higher responsibility by carbon dioxide emission of all industrial human activities, besides be a considerably expensive material, more than the rice husk ash in nature. Environmental benefits are generated in its utilization, because rice husk ashes are industrial process residues of the grain processing, that are discarded in the environment without none care. The using of these ashes in partial cement substitution in structural concrete, beside of the economical and environmental benefits, proportionate, in general, a higher useful life to the reinforced concrete structures. Based in theses environmental principles, this work aims at to study the technical and economical viability of the RHA utilization, substituting the cement partially, in concrete mixtures for conventional concrete. concrete prototypes with 20 x 20 x 70 cm, with and without ground and non-ground RHA, in 0%, 15% and 25% contents of cement substitution, with water/binder ratios of 0,45, 0,55 and 0,65. Exposed in natural environmental conditions (0,3 0,4% of CO2) the concrete prototypes were analyzed at 18, 24 and 30 months, to the axial compressive strength and carbonation by means of extraction of specimens perpendicularly cut to the casting direction, with 10 x 20 cm dimensions. The axial compressive strength at 18 months of the ground RHA mixtures were higher to the reference concrete, while the natural RHA ones were lower than the latter, with higher decreases for the 25% content than for 15%. The natural carbonation coefficients of reference concrete were the smallest ones, followed by the ground RHA with 15% and 25% and, after, with natural RHA, 15% and 25%. The results show that is possible substitute until 15% of cement by natural rice husk ash without pronounced strength losses (around 20%) and with carbonation coefficients between 4 and 5 mm.ano-0,5, values considered adjusted for conventional concrete.
O cimento é o material de construção com maior responsabilidade pela emissão do dióxido de carbono de todas as atividades industriais humanas, alem de ser um material consideravelmente mais caro do que as CCA s, in natura. Benefícios ambientais são gerados na sua utilização, pois as cinzas de casca de arroz são resíduos de processos industriais do beneficiamento do grão, que muitas vezes são descartados no meio ambiente, sem nenhuma preocupação ambiental. Usá-las em substituição parcial do cimento em concretos estruturais, além de benefícios econômicos e ambientais, proporciona, geralmente, uma maior vida útil às estruturas de concreto armado. Baseado nestes preceitos ambientais, esta pesquisa tem por objetivo o estudo da viabilidade técnica e econômica da utilização da cinza de casca de arroz (CCA), substituindo parcialmente o cimento nas misturas de concretos para uso em concreto convencional. Foram moldados protótipos de concreto de 20 x 20 x 70 cm, com CCA natural e moída, nos teores de 0, 15 e 25%, em substituição ao cimento, nas relações água/aglomerante 0,45, 0,55 e 0,65. Expostos em condições ambientais naturais (0,3 0,4% de dióxido de carbono), os protótipos de concreto foram analisados nas idades de 18, 24 e 30 meses, quanto à resistência, compressão axial e frente ao fenômeno de carbonatação natural, por meio da extração de testemunhos cortados perpendiculares à direção de moldagem, com dimensões 10 x 20 cm. A resistência à compressão axial a 18 meses dos traços com CCA moída foram superiores ao concreto de referência, enquanto que os de cinza natural foram menores do que as misturas com CCA moída, com quedas maiores para o teor de 25% do que para 15%. Os coeficientes de carbonatação natural do traço referência foram os menores de todos, seguidos dos CCA moída, com 15 e 25% e, após, com a CCA natural, de 15% e 25%. Os resultados mostram que é possível substituir até 15% de cimento por cinza de casca de arroz natural, sem moagem, sem perdas acentuadas de resistência (ao redor de 20%) e com coeficientes de carbonatação entre 4 e 5 mm.ano-0,5, valores que podem ser considerados adequados para concreto convencional.

A finalidade deste estudo foi verificar a resistência ao deslocamento de restaurações de Classe IV, ressaltando a sua capacidade de retenção com e sem a associação de pino(s) dentinários, bem como a comparação entre dentes humanos e bovinos, visando este último como possível substrato a dentes humanos em testes laboratoriais. Foram realizadas 60 cavidades de Classe IV com 6mm no sentido incisocervical e 3mm no sentido mesiodistal, tanto em dentes humanos como bovinos, com um bisel de 1mm de extensão, as quais foram divididas nos seguintes grupos: · G1- restaurações sem pino, sem condicionamento + adesivo (controle); · G2- restaurações com condicionamento ácido + adesivo; · G3- restaurações com um pino, sem condicionamento ácido + adesivo; · G4- restaurações com dois pinos, sem condicionamento ácido + adesivo; · G5- restaurações com um pino, com condicionamento ácido + adesivo; · G6- restaurações com dois pinos, com condicionamento ácido + adesivo. A aplicação do sistema adesivo (Single Bond) e a inserção da resina composta (Z 100) deu-se de acordo com as instruções do fabricante. Após a realização das restaurações, os corpos-de-prova foram armazenados por um período de 72 horas a 37+1oC antes de serem levados à máquina de ensaios universal para serem submetidos à carga de compressão. A análise estatística aplicada aos resultados obtidos segundo as condições experimentais em que foi realizado este trabalho permitiu as seguintes conclusões: - a presença de um ou dois pinos rosqueados em dentina apresentou tendência em aumentar a resistência ao deslocamento das restaurações de Classe IV quando associadas ao sistema adesivo; - a utilização de um pino dentinário proporcionou aumento na retenção das restaurações de Classe IV, todavia, não suficiente para suplantar estatisticamente as restaurações adesivas sem essa variável; - a utilização de dois pinos dentinários proporcionou aumento estatisticamente significante na resistência ao deslocamento das restaurações,em relação às realizadas apenas com o sistema adesivo; - não existiu diferença na resistência ao deslocamento das restaurações de Classe IV realizadas em dentes bovinos e em dentes humanos.
The goal of this study was to verify the resistance to displacement of Class IV restorations, emphasizing their retention capacity with and without the association of retentive pins (Pinlock), as well as the comparison between human and bovine teeth, aiming at the latter as a possible substrate to human teeth in laboratory tests. Sixty Class IV cavities with 6 mm in the incisal-cervical plane and 3 mm in the mesio-distal plane and with bevel 1mm were performed, both on human and bovine teeth, which were divided into the following groups: · G1 - restorations without acid conditioning and pin + adhesive (control); · G2 - restorations with acid conditioning + adhesive; · G3 - restorations without acid conditioning + one pin + adhesive; · G4 - restorations without acid conditioning + two pins + adhesive; · G5 - restorations with one pin + acid conditioning + adhesive +; · G6 - restorations with two pins + acid conditioning + adhesive. The application of the adhesive system (Single Bond) and the insertion of composite resin (Z100) were according to the manufacturer's instructions. Following restoration procedures, the specimens were stored for a period of 72 hours at 37+ oC prior to being taken to the Universal testing machine, so as to be submitted to compression load. The statistical analysis applied to the results obtained, according to the experimental conditions in which this study was performed, allowed the following conclusions:- the presence of one or two dentin-threaded pins showed a trend in increasing the displacement resistance of Class IV restorations when associated with the adhesive system; - the utilization of one dentinal pin afforded an increase in the retention of Class IV restorations, nevertheless, not sufficient to supersede the adhesive restorations statistically without this variable; - the utilization of two dentinal pins afforded a statistically significant increase in the displacement resistance of restorations, in relation to those performed only with the adhesive system; - there was no difference as to displacement resistance of Class IV restorations performed on both bovine and human teeth.

Foram avaliados os resultados, as alterações hemodinâmicas sistêmicas e as alterações da sensibilidade geral superficial de 31 doentes com neuralgia idiopática do trigêmeo tratados com a técnica de compressão percutânea do gânglio trigeminal com balão sob anestesia geral associadamente ou não ao bloqueio anestésico do gânglio trigeminal com lidocaína. As características biométricas, demográficas e clínicas foram similares nos doentes tratados (CBA) ou não (SBA) com bloqueio anestésico. As médias das pressões arteriais sistólicas (PASs), médias (PAMs) e diastólicas (PADs) e das frequências cardíacas foram analisadas nos momentos preoperatório imediato, anestesia geral e sem manipulação operatória, punção ganglionar, insuflação do balão e despertar e as sensibilidades faciais nos momentos pré-operatório e de 30 e 210 dias posoperatórios. As médias das PASs, das PAMs e das PADs foram inferiores nos doentes do grupo CBA em relação às dos doentes do grupo SBA nos momentos punção ganglionar e insuflação do balão do balão e as médias das PAMs e PADs foram inferiores nos doentes do grupo CBA em relação às do grupo SBA no momento despertar. Ocorreu elevação da PAS, PAM e PAD em todos os doentes hipertensos ou não do grupo SBA. Ocorreu elevação da PAM em 16,7% dos normotensos e em 33,3% dos hipertensos e em 33,3% dos normotensos e em 11,1% dos hipertensos do grupo CBA, respectivamente, nos momentos, punção ganglionar e insuflação do balão. Ocorreu hipertensão arterial em 50 a 75% dos doentes do grupo SBA e em zero a 7% dos doentes do grupo CBA nos momentos punção ganglionar e insuflação do balão. Todos os doentes normotensos do grupo CBA apresentaram redução da PAS e da PAM e, 83,3%, também da PAD no momento punção do gânglio trigeminal. Ocorreu redução da PAS e da PAM em 83,3% dos doentes normotensos do grupo CBA e, em 66,7%, da PAD no momento insuflação do balão. Em 55,6% dos hipertensos do grupo CBA ocorreu redução das PAS e da PAM e, em 66,7%, da PAD no momento punção ganglionar. Observou-se redução da PAS em 66,7% dos doentes hipertensos do grupo CBA e da PAM e da PAS em 88,9%. Ocorreu redução da PAS e da PAM em 83,3% dos doentes normotensos do grupo CBA e da PAD em 66,7%. Ocorreu hipotensão arterial em 27% a 33% dos doentes do grupo CBA e em nenhum dos do grupo SBA. As frequências cardíacas dos doentes do grupo SBA elevaram-se e mantiveram-se mais elevadas que as dos do grupo CBA nos momentos anestesia geral sem manipulação operatória, punção ganglionar, insuflação do balão e despertar. Todos os doentes do grupo SBA e 90% dos do grupo CBA não apresentavam dor sete meses após a operação. Ocorreu recidiva da dor em 26,7% dos doentes; ocorreu em uma a 128 (71,13 ± 55,23) semanas após a cirurgia ou seja em 121,07 ± 23,05 semanas em média; não houve diferença estatisticamente significativa entre os doentes dos grupos SBA e CBA quanto à recidiva ou não da dor. Na avaliação de 30 e 210 dias, os valores da algiometria na região do segundo ramo (V2) do nervo trigêmeo nos doentes do grupo CBA foram mais elevados em ambos os lados da face que nos doentes do grupo SBA e não se modificaram ao longo do período das avaliações. A algiometria no território do primeiro ramo (V1) do nervo trigêmeo não se modificou ao longo dos sete meses de avaliação e não diferiu entre os doentes de ambos os grupos. A maioria dos doentes apresentava hipoalgesia no território de inervação de V2 e V3 um mês após a operação; a sensibilidade dolorosa não se modificou em cerca de metade dos doentes de ambos os grupos e manteve-se inalterada em 25% a 33% dos doentes A intensidade da dormência e do incômodo associado a ela foram maiores um e sete meses após a operação nos doentes de ambos os grupos; 14,3% dos doentes do grupo SBA não apresentava sensação de dormência facial um mês após a operação. Todos os doentes do grupo SBA e 90% dos do grupo CBA apresentavam dormência facial sete meses após a operação. Sete meses após a operação, a sensibilidade dolorosa no território de V1 não se modificou em metade dos doentes de ambos os grupos, foi normal na região de V2 em 50% e 41,7% dos doentes dos grupos CBA e SBA, respectivamente, e na região de V3 em 40% dos doentes do grupo CBA e em nenhum do grupo SBA, respectivamente. As alterações da sensibilidade dolorosa na região de V3 foram menores nos doentes do grupo CBA que nos do grupo SBA. Houve aumento de doentes do grupo SBA que apresentaram hipoalgesia facial nas regiões de V1, V2 e V3 um mês após a operação. Nos doentes do grupo CBA ocorreu hipoalgesia apenas na região de V3 um mês após a cirurgia e redução não significativa destas alterações sete meses após. O exame da sensibilidade ao frio foi normal no território de V1 em cerca de metade dos doentes um mês após a operação; houve aumento da proporção de doentes com hipoestesia ou anestesia ao frio nos territórios de V2 ou V3. Na maioria dos doentes, a sensibilidade ao frio nos territórios de V1 e V2 normalizou-se, mas manteve-se comprometida no território de V3 sete meses após a operação. Nos doentes do grupo SBA não se identificaram alterações significativas da sensibilidade facial ao frio nas regiões de V1 e V2, mas ocorreu aumento significativo de casos com hipoestesia ao frio na região de V3 um e sete meses após a operação. Houve hipoestesia ao frio somente na região de inervação de V2, um e sete meses após a operação nos doentes do grupo CBA. Um mês após a operação, a proporção de doentes com sensibilidade normal ao calor reduziu-se para 42,9% e 21,4% em V1 e V3, respectivamente, nos doentes de ambos os grupos. Sete meses após a operação, a proporção de doentes com sensibilidade normal ao calor reduziu-se para 33,3%, 41,7% e 8,3%, respectivamente, em V1, V2 e V3 nos doentes do grupo SBA e elevou-se para 50,0%, 40,0% e 40,0% respectivamente, nos doentes do grupo CBA, mas as diferenças não foram significativas. Ocorreu aumento significativo da hipoestesia ao calor apenas na região de inervação de V3 dos doentes do grupo SBA e do número de doentes do grupo CBA com hipoestesia ao calor nas regiões de inervação de V2 e V3 um e sete meses após a operação. Não houve diferença estatisticamente significativa entre os doentes de ambos os grupos quanto à sensibilidade tátil nos momentos preoperatório, um mês e sete meses após a operação. Os doentes do grupo SBA apresentaram significativa hipoestesia tátil no território de V1 ao longo dos períodos de avaliação. Não houve diferença estatística entre os grupos em relação ao exame da sensibilidade tátil no território de V2 e de V3 ao longo dos momentos da avaliação. Evidenciou-se hipoestesia tátil no território de V3 ao longo das avaliações pós-operatórias nos doentes do grupo SBA e não houve alterações significativas da sensibilidade tátil ao longo das avaliações nos doentes do grupo CBA. Não ocorreu diferença entre os doentes de ambos os grupos quanto aos achados da pesquisa do reflexo corneopalpebral ao longo das avaliações
The clinical results, the systemic hemodynamic reactions and the modification of the general superficial sensorial examination of 31 patients with idiopathic trigeminal neuralgia treated with percutaneous compression technique of the trigeminal ganglion with balloon under general anesthesia associated or not with block the trigeminal ganglion with local anesthetic were evaluated. The biometric, demographic and clinical characteristics were similar in patients treated (CBA) or not (SBA) with trigeminal ganglion block. The averages of the systolic (PASs), mean (PAMs) and diastolic (PADs) arterial pressures and heart rates were evaluated in the preoperative period, during the general anesthesia and before the surgical manipulation, during the trigeminal ganglion puncture, during the balloon expansion and the awakening period and the facial sensibility at the immediate preoperative and at the 30th and 210th postoperative days. In the CBA group, the averages of PASs, PAMs and PADs were lower than in CBA patients during the trigeminal ganglion puncture and expansion of the balloon and the averages of the PAMs and PADs were lower in CBA patients than in SBA patients during the awakening period. There was increasing of the mean PAS, PAM and PAD on all hypertensive or not SBA patients. There was increasing of the PAM in 16.7% of the normotensive and in 33.3% of the hypertensive and in 33.3% of normotensive CBA patients and in 11.1% of hypertensive CBA patients, respectively, at the trigeminal ganglion puncture and balloon inflation times. Arterial hypertension was diagnosed in 50 to 75% of SBA patients and in none to 7% of CBA patients during the trigeminal ganglion puncture and balloon expansion. All normotensive CBA patients presented PAS and PAM reduction and 83.3%, also presented PAD reduction at the time of the trigeminal ganglion puncture. The PAS and PAM reduced in 83.3% of the normotensive CBA patients, and the PAD in 66.7% during the balloon inflation. In 55.6% of the hypertensive CBA patients, there was reduction of PAS and also of the PAM and in 66.7% of the PAD at the time of trigeminal ganglion puncture. There was reduction of PAS in 66.7% of hypertensive CBA patients and of the PAM and PAS in 88.9% of them. There was reduction of PAS and PAM in 83.3% of the normotensive CBA patients and of PAD in 66.7%. Arterial hypotension was observed in 27% to 33% of the CBA patients but not in the SBA patients. The cardiac rates of the SBA patients increased and remained higher than those of the CBA patients during the general anesthesia period previous to the surgical manipulation, trigeminal ganglion puncture, balloon expansion and awakening. All SBA and 90% of the CBA patients had no pain seven months after the operation. There was pain recurrence in 26.7% of the patients in one to 128 (71.13 ± 55.23) weeks after the surgical procedure, that is 121.07 ± 23.05 weeks of the postoperative period in average; there was no difference between SBA and CBA patients in relation to pain recurrence rate. The algiometry values in the region of the second branch (V2) of the trigeminal nerve in the CBA patients were higher on both sides of the face that in SBA patients in the 30th and 210th postoperative days. There was no difference between patients of both groups regarding the averages of the values of the postoperative algiometry. The algiometry did not change in the first branch (V1) of the trigeminal nerve over the seven months of the follow-up period and did not differ statistically between the patients from both groups. The majority of patients presented hipoalgesia in the territory of V2 and V3 one month after the operation. The hypoalgesia did not change in about half of the patients of both groups and remained unchanged in 25% to 33% of the patients. The intensity of the numbness and of the associated bad feeling were higher one and seven months after surgery in the patients of both groups. All SBA and 90% of CBA patients presented facial numbness seven months after the operation. Seven months after the operation, the numbness in the territory of V1 did not change in half the patients from both groups, was normal in the region of V2 in 50% and 41.7% of patients of the CBA and SBA groups, respectively, and in the region of V3 in 40% of patients of the CBA and in none of the SBA group, respectively. The pain sensory changes in V3 were smaller in the CBA than in SBA patients. There was increasing in the number of SBA patients who presented V1, V2 and V3 hipoalgesia of one month after the operation. Hypoalgesia was observed just in the V3 territory of the CBA patients one month after surgery and non-significant reduction of this finding seven months after the procedure. The sensitivity to cold was normal in the territory of V1 in about half of patients a month after the operation. There was increasing in the proportion of patients presenting hypoesthesia or anesthesia to cold in the territories of V2 or V3. In most patients, coldness perception in the V1 and V2 territories normalized but remained altered in the territory of V3 seven months after the operation in many of them. There were not significant changes in the facial sensitivity to cold in V1 and V2 territories in the SBA patients, but there was a significant increase of cases with cold hypoesthesia in the region of V3 one and seven months after the operation. There was cold hypoesthesia in the V2 region seven months after surgery in of CBA patients. One month after the operation, the proportion of patients from both groups with normal perception of heat in the face reduced to 42.9% and 21.4% in V1 and V3, respectively. Seven months after the operation, the proportion of patients with normal sensitivity to heat fell to 33.3%, 41.7% and 8.3%, respectively, in V1, V2 and V3 of patients from the SBA group and increased to 50.0%; 40.0% and 40.0%, respectively, in CBA patients, but the differences were not significant between both groups. There was a significant increase of heat hypoesthesia in V3 region, one and seven months after surgery in SBA patients. There was significant increase in the number of CBA patients presenting V2 and V3 heat hypoesthesia, one and seven months after the operation. There was no significant difference in the tactile sensitivity between the patients of both groups in the preoperative period and one month and seven months postoperatively. SBA patients presented significant tactile hypoesthesia in the V1 territory over the evaluation period. There was no difference between both groups of patients related to tactile sensitivity in the V2 territory during the follow up period. There was no difference between the groups in relation to V3 tactile sensitivity in the evaluation period. There was V3 tactile hypoesthesia along the post-operative evaluations in the SBA patients. There were no significant changes in the tactile sensitivity along the evaluations in the CBA patients. No difference was observed in the evaluation of the corneal reflex in the patients of both groups during the follow-up period

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Accessing data anywhere and anytime, via mobile devices, is a very present reality nowadays. However, even with technological advances, such de-vices may have limited computing resources, such as available secondary mem-ory space and data processing capacity. It is well known that data compression feature may reduce significantly the size of databases as well as improve the performance of I/O intensive workloads. This work presents an approach for data compression to be applied over data existing in such devices to optimize the memory space. The used framework implements a storage column oriented architecture. One of the major advantages concerning this approach is its effect on compression, because data is stored in columns, and there is only one type of data in each column, thus it is possible to use the most appropriate technique for each data type. Experimental results show that the proposed technique reduces the space allocated to store data on mobile devices, and ensures reasonable data access time to access compressed data. The compression technique does not jeopardize data access efficiency. Keywords: Database, Mobile database, Data compression, Column-oriented database.
Acessar dados em qualquer lugar e a qualquer momento, através de dispositivos móveis, é uma realidade muito presente nos dias atuais. Porém, mesmo com os avanços tecnológicos, tais dispositivos apresentam recursos computacionais limitados, tais como espaço de memória secundária e capacidade de processamento. Quando se utiliza esse tipo de dispositivo reduzir o espaço de memória usado é um aspecto critico. Porém, o uso da compressão de dados pode reduzir significativamente o espaço dos dados desses dispositivos, bem como melhorar a performance de E/S. Esse trabalho apresenta um mecanismo eficiente para a compressão de dados em dispositivos móveis que otimiza o espaço em memória, além de não pôr em risco a eficiência do acesso aos dados. O mecanismo tem como base uma arquitetura de armazenamento orientada à coluna. Uma das principais vantagens desse tipo de armazenamento é a compressão, pois os dados são armazenados em colunas, e existe apenas um tipo de dados em cada coluna, assim é possível utilizar a técnica de compressão mais adequada para cada tipo de dado. Resultados experimentais mostram que a técnica de compressão proposta reduz o espaço alocado para armazenar os dados em dispositivos móveis, e garante o acesso aos dados compactados num tempo razoável. Palavras-chave: Banco de Dados, Banco de Dados Móveis, Banco de Dados Orientado a Coluna, Compressão de Dados.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2014
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Compressores lineares apresentam baixos carregamentos transversais no pistão, possibilitando a utilização do próprio fluido refrigerante para formar um mancal aerostático na folga pistão-cilindro. Ao passo que esse arranjo reduz o efeito de fricção no mancal, o escoamento de gás na folga pistão-cilindro gera perdas que reduzem a eficiência do compressor. A presente dissertação apresenta um modelo desenvolvido para avaliar essas perdas e seus efeitos sobre as eficiências volumétrica e isentrópica de um compressor linear operando sem óleo lubrificante. A simulação do escoamento transiente na folga é realizada com um código comercial baseado no método de volumes finitos, enquanto que o ciclo de compressão no cilindro é simulado com um modelo de formulação integral. De modo a evidenciar as perdas geradas no mancal aerostático, o modelo desconsidera ineficiências associadas aos processos de sucção e descarga, bem como ao superaquecimento do gás no cilindro. O fenômeno foi investigado para diferentes parâmetros de projeto, assumindo que o pistão e cilindro se mantém concêntricos durante o ciclo de compressão. Verificou-se um decréscimo na eficiência do compressor com os aumentos da espessura da folga e da razão de compressão, mas o efeito oposto foi observado com o aumento da velocidade de operação.

Abstract : The piston of linear compressors experience low transversal loads and the refrigerant gas in the piston-cylinder clearance can be used to form an aerostatic bearing. Despite the reduction of friction in the bearing, the gas flow in the piston-cylinder clearance generates losses that decrease the compressor efficiency. The present dissertation reports a model developed to evaluate such losses and their effects on the volumetric and isentropic efficiencies for an oil-free linear compressor. The transient flow in the gap is simulated with a commercial code based on the finite volume method, whereas the compression cycle in the cylinder is characterized via a lumped model. The attention is focused on the flow losses and other inefficiencies, associated with gas superheating inside the cylinder and with suction and discharge processes, are not included in the analysis. Different design parameters were considered in the analysis and the cylinder and the piston are assumed to be concentric during the compression cycle. It was found that the compressor efficiency is reduced when the clearance dimension and pressure ratio are increased, but the opposite effect was observed in relation to the operation speed.

The thesis is concerned with multi-criteria evaluation of alternatives of modernization of compressor station for natural gas. This thesis is divided into practical part and theoretical part. The theoretical part will introduce historical development of the gas industry and the current state of the gas network in our country. The following describes a method for operating a compressor station, its technology units and existing operational processes. The theoretical part is a chapter that describes methods of multi-criteria evaluation of alternatives and a way of specifying the methods suitable for constructing weights of the criteria. The fifth chapter contains an application example, the aim of which is to choose the suitable way of modernization of the compressor station that would meet the requirements of planned projects. Creating recommendations for the management of the company fulfilled the goal of this thesis.

A força de compressão entre os fragmentos é um importante fator que interfere na consolidação das fraturas. O objetivo deste trabalho foi avaliar a eficácia de cada um dos parafusos sem cabeça de auto compressão com três diâmetros de rosca diferentes, empregados no tratamento das fraturas do escafoide. Utilizando um dispositivo de alumínio acoplado à uma máquina universal de ensaios equipada com uma célula de carga de 50 kgf. Foram utilizados dois blocos de espuma rígida de poliuretana de densidade 0,16 g/cc. Os testes foram realizados com os parafusos HCS da marca Synthes®, com diâmetros de 3,0 mm, 2,4 mm e 1,5 mm. Todos tinham 20 mm de comprimento. Os parafusos foram introduzidos utilizando os princípios da técnica AO, sendo o instrumental fornecido com os parafusos. Foram realizados com os parafusos supracitados fixações com inserção a 90º, 60º, 45º e 30º de inclinação em relação à superfície do bloco. Todos procedimentos foram repetidos por sete vezes, comparando-se os valores obtidos do pico da força de compressão (Força Max), da força de compressão após 20 segundos (Força T1) e da força de compressão após 300 segundos (Força T2). Para as fixações dos parafusos de 3.0 mm e 2.4 mm com 30º de inclinação não houve compressão, devido ao rompimento da superfície do bloco pela rosca da extremidade proximal dos parafusos. A Força Max do parafuso HCS de 3.0 mm foi maior do que a dos parafusos de 2.4 mm em todas as comparações. A relação entre as Força T2/Força T1 foram semelhante em todas as comparações, isto é, não apresentaram diferença estatística, e demostraram que a acomodação dos parafusos não foi relacionada ao diâmetro da rosca dos parafusos. Concluímos que a força de compressão entre os fragmentos foi maior quando o diâmetro da rosca do parafuso também foi maior, independente da posição da inserção em relação à fratura
The interfragmentary compression force is an important factor for fracture healing. The aim of this study was to evaluate the effectiveness of each three different diameters headless compression screw, used for the treatment of scaphoid fractures. It was used an aluminum device coupled to a universal testing machine equipped with a load cell of 50 kgf. Two rigid foam blocks made of polyurethane with density of 0.16 g/cc. The tests were performed with the HCS Synthes® with 20 mm length 3.0 mm, 2.4 mm and 1.5 mm in diameter. The screws were inserted using the AO technique and instrumental provided with screws. They were performed with the above screw with 90º, 60º, 45º and 30º tilt with the block and repeated seven times and comparing the results obtained from the peak compression force (Max Force) to compression force after 20 seconds (T1 Force) and compression force after 300 seconds (T2 force). For the fixations of 3.0 mm and 2.4 mm screws with 30° tilt no compression were reached, as the proximal threads of the screws broke the surface of the block. Max Force for HCS 3.0 mm was higher than the 2.4 mm screws in all comparisons. The relationship T2 Force / T1 Force was similar in all comparisons, showing no statistical difference, proving that the accommodation of the screws is not related to the threads diameter of the screws. It was concluded in this work that there was a reduction of interfragmentary compressive force by reducing the threads diameter of the screws, regardless of the position placed over the fracture surface

Este trabalho tem como objetivo investigar o comportamento pós-pico de pilares com concretos de alta resistência confinados com e sem adição de fibras metálicas, submetidos à flexo-compressão. Para tanto, realizou-se inicialmente uma extensa revisão bibliográfica sobre o tema, na qual, elencaram-se os principais fatores que influenciam o comportamento pós-pico desses elementos estruturais. Em seguida, desenvolveram-se estudos paramétricos com o intuito de estabelecer os modos de influência de cada fator. Com base nesses estudos preliminares, um programa experimental, dividido em duas fases, foi proposto. Na primeira fase, ensaiaram-se vinte e seis pilares de concreto armado e 14 pilares de concreto simples. Três fatores foram estudados: a taxa de adição de fibras metálicas, a taxa de armadura transversal e a resistência à compressão do concreto. Os pilares possuíam seções transversais quadradas com dimensões 15 cm x 15 cm e altura de 50 cm e foram ensaiados à compressão centrada com controle de deslocamento. Observou-se que os três fatores analisados influenciam diretamente a ductilidade desses elementos estruturais e que, por meio de adição de fibras metálicas, é possível garantir índices de ductilidade aceitáveis para os pilares com concreto de alta resistência. Outrossim, analisando-se os diagramas força vs. deformação dos pilares, observou-se que para o primeiro pico de força, toda a seção resiste a esforços de compressão e que a adição de fibras melhora o trabalho conjunto entre o cobrimento e o núcleo do pilar. Finalizando esta fase, propuseram-se modificações para o modelo para concreto confinado de Cusson e Paultre (1995), de modo que, permitisse ao mesmo modelar o comportamento do concreto confinado com e sem adição de fibras metálicas. Na segunda fase do programa experimental, quinze pilares de concreto armado foram ensaiados a compressão excêntrica. Essa fase teve como objetivo investigar a influência da excentricidade, da taxa de armadura transversal e da taxa de adição de fibras metálicas no comportamento pós-pico desses elementos estruturais. Os pilares, nessa fase, possuíam seção transversal quadrada com dimensões de 15 cm x 15 cm e altura de 170 cm. Para realização dos ensaios foi confeccionado um par de rótulas unidirecionais, as quais apresentaram excelente desempenho, conseguindo transferir integralmente o momento externo aplicado ao pilar. Observou-se que, tanto a flambagem das barras da armadura longitudinal, quanto a perda de massa de concreto nesses pilares ocorrem de modo bem mais crítico que nos pilares submetidos à compressão centrada. Constatou-se, ainda, que quando os valores dos três fatores analisados são elevados, a ductilidade desses elementos estruturais é melhorada. Finalmente, foi observado que o efeito da flexão faz com que as tensões de confinamento se distribuam de modo diferenciado dentro da seção transversal dos pilares; contudo, observou-se que a tensão de confinamento na região comprimida da seção transversal pouco é modificada.
This thesis aims to investigate the ductility of high strength concrete columns, with confinement and/or with steel fibre addition, under combined axial load and bending. For this, an extensive survey was performed, and the main factors, which influence the column ductility, were pointed out. Then, parametric studies were done, aiming to establish the mode of influence of each factor. Based on these preliminaries studies, an experimental investigation, divided in two steps, was proposed. In the first part, twenty-six reinforced concrete columns and fourteen concrete columns were tested and three factors were analysed: the ratio of fibre addition, the transversal reinforcement ratio and the concrete compressive strength. The columns have 15 cm x 15 cm square cross section and were 50 cm high. They were tested under concentric load with displacement control. It was observed that all factors interfere in the columns\' ductility, and that, by adding fibre in the concrete, is possible to provide acceptable ductility index to high strength concrete columns. The load vs. column strain diagrams were studied and it was verified that for the first load peak, all the column cross section resists the axial load. Besides that, it was observed that the fibre addition improves the work together between the cover and the column core. Finally, several modifications to the concrete confinement model of Cusson and Paultre (1995) were proposed to allow this model to analyse the compressive behaviour of the confined concrete with or/not fibre addition. In the second part of the experimental program, fifteen reinforced concrete columns were tested under eccentric load. The effects of the load eccentricity, the ratio of steel fibre addition and the transversal reinforcement ratio on the column ductility were investigated. The columns have 15 cm x 15 cm square cross section and were 170 cm high. A pair of unidirectional hinges was design, which presented exceptional performance, transferring integrally the external applied moment to the columns. A most critical model of longitudinal reinforcement buckling and mass lost was observed. In addition, it was verified that when the values of all factors were increased, the column ductility was improved. Finally, a different distribution mode of the confinement pressure on the column cross section was observed, when combined axial load and bending is applied. Nevertheless, the confinement pressure on the compressive region of the column cross section is not modified.

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As demandas por soluções de comunicações de redes sem fio (tecnologia wireless) estão integradas ao cotidiano e cada dia mais inseridas e valorizadas em nosso meio. Neste trabalho realizou-se o estudo da viabilidade de utilização da rede sem fioWPAN (padrão IEEE 802.15.4) na transmissão de imagens e vídeo utilizando o padrão ZigBee. Utilizou-se neste trabalho, linguagens de programação JAVA e C, o software livre Atube Catcher para compressão de vídeos, módulos de conexão, placas e transceptor da Atmel. A comunicação e configuração dos módulos para a transmissão de dados pelo padrão ZigBee são realizadas através da porta serial. Testes efetuados com imagens e vídeo MPEG-4 mostraram a viabilidade desta transmissão, tendo sido feitas medições com compressão de arquivos com imagens e vídeo, das perdas de pacotes com distância e da latência de transmissão dos dados
The demand for wireless network communications solutions technology wireless are integrated into the everyday and each day more embedded and valued in our midst. In this work the study of the feasibility of using wireless networkWPAN (IEEE 802.15.4) for video transmission with the Zigbee standard was done. For improve the capability of transmission of images and video compression techniques were used. For accomplish of this work the following tools are used: JAVA and C programming languages, aTube Catcher free software for video compression, connection modules, Atmel boards and transceiver. Tests were performed with images and MPEG-4 video and the results showed the feasibility of transmission. Besides, measurements with file compression with images and video, packet loss ratio with distance and data transmission latency were made

Orientador: Nobuo Oki
Banca: Sergio Azevedo de Oliveira
Banca: Tércio Alberto dos Santos Filho
Resumo: As demandas por soluções de comunicações de redes sem fio (tecnologia wireless) estão integradas ao cotidiano e cada dia mais inseridas e valorizadas em nosso meio. Neste trabalho realizou-se o estudo da viabilidade de utilização da rede sem fioWPAN (padrão IEEE 802.15.4) na transmissão de imagens e vídeo utilizando o padrão ZigBee. Utilizou-se neste trabalho, linguagens de programação JAVA e C, o software livre Atube Catcher para compressão de vídeos, módulos de conexão, placas e transceptor da Atmel. A comunicação e configuração dos módulos para a transmissão de dados pelo padrão ZigBee são realizadas através da porta serial. Testes efetuados com imagens e vídeo MPEG-4 mostraram a viabilidade desta transmissão, tendo sido feitas medições com compressão de arquivos com imagens e vídeo, das perdas de pacotes com distância e da latência de transmissão dos dados
Abstract: The demand for wireless network communications solutions technology wireless are integrated into the everyday and each day more embedded and valued in our midst. In this work the study of the feasibility of using wireless networkWPAN (IEEE 802.15.4) for video transmission with the Zigbee standard was done. For improve the capability of transmission of images and video compression techniques were used. For accomplish of this work the following tools are used: JAVA and C programming languages, aTube Catcher free software for video compression, connection modules, Atmel boards and transceiver. Tests were performed with images and MPEG-4 video and the results showed the feasibility of transmission. Besides, measurements with file compression with images and video, packet loss ratio with distance and data transmission latency were made
Mestre

Antarctic ice shelves control the ice flux from the continent to the ocean. As such, they play a major role in the stability of the ice sheet and its potential contribution to sea level rise, especially in the context of global change. Below some of these ice shelves, marine ice can be found which is a product of the Deep Thermohaline Circulation. Due to its specific genetic process, marine ice has intrinsic physical (grain size, ice fabric, bubble content, ) and chemical (impurities, water stable isotopes) properties, that differ from those of 'meteoric ice' formed on the continent through snow metamorphism or 'sea ice' resulting from sea water freezing at the ocean-atmosphere surface. Until now however, the effect of these specific properties on marine ice rheology is still very poorly understood.

The principal objective being to include realistic mechanical parameters for marine ice in ice shelf flow models, uniaxial compression experiments have been performed on various types of marine ice samples. Technical developments are an important component of this thesis has they were necessary to equip the laboratory with the appropriate tools (pneumatic rig, automatic ice fabric data handling).

Results from experimental compression on isotropic marine ice show that it represents the higher boundary for meteoric ice viscosity throughout the whole temperature range, thereby validating Cuffey and Paterson's relationship with an enhancement factor equals to 1.

Marine ice is however often quite anisotropic, showing elongated crystals and wide single maximum fabric, that should impact its mechanical properties. Experiments on pre-oriented marine ice samples have therefore been carried out combining the study of epsilon_{oct} vs. tau_{oct} with a thorough analysis of microstructural data 'before' and 'after' the experiment.

Depending on the orientation of the sample in the applied stress field and on the intensity of the latter, anisotropic marine ice can be harder or softer than its isotropic counterpart, with n=4 often observed in Glen's flow law. Associating the experimental geometrical settings to potential natural equivalent, results suggest that anisotropic marine ice would strengthen ice shelf flow in most areas (for a same given temperature), apart from suturing areas between individual ice streams as they merge to form the ice shelf, where it could become weaker than meteoric ice in certain circumstances.

Finally, preliminary sensitivity studies, using a simple ice shelf model with our experimental parameters of Glen's flow law have allowed us to discuss the potential impact of rift location, rift size and thermal regime in the ice shelf behavior.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

Understanding the interaction of sea ice with offshore structures is of primary importance for the development of technology in cold climate regions. The rheological properties of sea ice (strength, creep, viscosity) as well as the roughness of the contact surface are the main factors influencing the type of interaction with a structure. A device was developed and designed and small scale laboratory experiments were carried out to study sea ice frictional interaction with steel material by means of a uniaxial compression rig. Sea-ice was artificially grown between a stainless steel piston (of circular cross section) and a hollow cylinder of the same material, coaxial to the former and of the same surface roughness. Three different values for the roughness were tested: 1.2, 10 and 30 μm Ry (maximum asperities height), chosen as representative values for typical surface conditions, from smooth to normally corroded steel. Creep tests (0.2, 0.3, 0.4 and 0.6 kN) were conducted at T = -10 ºC. By pushing the piston head towards the cylinder base, three different types of relative movement were observed: 1) the piston slid through the ice, 2) the piston slid through the ice and the ice slid on the surface of the outer cylinder, 3) the ice slid only on the cylinder surface. A cyclic stick-slip motion of the piston was detected with a representative frequency of 0.1 Hz. The ratio of the mean rate of axial displacement to the frequency of the stick-slip oscillations was found to be comparable to the roughness length (Sm). The roughness is the most influential parameter affecting the amplitude of the oscillations, while the load has a relevant influence on the their frequency. Guidelines for further investigations were recommended. Marco Nanetti - seloselo@virgilio.it

Les matériaux composites utilisés actuellement en mer sont presque tous fabriqués avec des résines thermodurcissables (polyester, époxy). Il existe aujourd’hui une alternative aux matrices thermodurcissables: les matrices thermoplastiques (PP, PA, PPS, PEEK…). Celles-ci offrent la possibilité d’une mise en forme par chauffage local associée à des propriétés mécaniques très intéressantes et un recyclage possible en fin de vie. Les raisons pour l’adaptation lente de ces matériaux est qu’ils nécessitent une mise en œuvre complètement différente du fait de leur microstructure particulière et du manque d’expérience sur ce type de matériau pour des structures épaisses. Le but de ce projet est de designer, fabriquer et tester une enceinte en composite thermoplastique pour des profondeurs de 4500 mètres, afin d‘établir l’intérêt technique, écologique et économique de ces matériaux sur ce marché. De nombreux matériaux existent mais des questions se posent concernant la sensibilité à l’eau de matériaux composites moins chers comme le C/PA6, plus particulièrement sur son effet sur les propriétés mécaniques. Dans cette étude, un modèle de diffusion spécifique a été développé et des relations semiempiriques ont été proposées pour prendre en compte l’effet du vieillissement sur les propriétés mécaniques. L’effet des conditions de fabrication a également été étudié en détail et les résultats ont montré qu’il y avait un effet important de la mise en œuvre sur les propriétés. Enfin des cylindres épais en C/PA6 ont été fabriqués puis testés jusqu’à implosion. Les résultats ont montré qu’il était possible d’utiliser ce type de matériau pour des applications sous-marines car ceux-ci ont implosé à des pressions supérieures à 600 bar
The composite materials used at sea are today nearly all based on thermoset resins (polyester, epoxy). However, there is an increasing number of thermoplastic matrix polymers available on the market (PP, PA, PPS, PEEK…), which offer possibilities for forming by local heating, attractive mechanical properties and the potential for end of life recycling. The reasons for the slow adoption of these materials are that they require a completely different manufacturing route compared to the current materials, they have more complex microstructure, and that there is little experience with them, particularly for thick structures. The aim of this study is to design, manufacture and test thermoplastic composite pressure vessels for 4500 meter depth, in order to establish a technical, economic and ecological assessment of the use of these materials to replace traditional composites underwater. Various material options exist but there are questions concerning the water sensitivity of less expensive thermoplastic composites (C/PA6) for these applications, more especially concerning its effect on the mechanical properties. In this study, a specific water diffusion model has been developed and semi-empirical relationships have been proposed to account for the effect of water on the mechanical properties. The effect of processing conditions have also been addressed and have shown a strong effect on the mechanical properties. Finally, thick thermoplastic cylinders were manufactured and tested until implosion. Results showed that it is possible to use C/PA6 thermoplastic composite cylinders for deep sea applications as these imploded at pressures higher than 600 bar

Orientador: Raul Raposo de Medeiros
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: Dez cães mestiços, machos, foram submetidos à laparotomia, com limpeza intra-operatória do conteúdo intestinal, e à realização de secções transversas do cólon a 10 e 20 em da transição ileocólica, respectivamente. As extremidades foram, então, anastomosadas utilizando-se a técnica de sutura com pontos separados seromuscu1ares e justaposição das bordas usando-se o fio de poligluconato 4.0 na anastomose proximal. Na distal, utilizou-se a técnica de compressão sem sutura, usando-se o anel biofragmentável, BAR ("biofragmentable anastomosis oring") . Os cães foram mantidos sob a observação clínica durante um período de 30 dias, após o qual foram novamente anestesiados e, em seguida, sacrificados, para a retirada do segmento de cólon que continha as duas anastomoses. Realizaram-se análise das alterações macroscópicas verificadas na inspeção da cavidade peritoneal e comparações entre os índices de estenose, resistência das anastomoses à insuflação gasosa e aspectos da superfície das mesmas. Pela análise microscópica verificou-se a coaptação das bordas; a espessura da parede; o grau de necrose tecidual; a reação inflamatória; a proliferação de fibroblastos; a formação de fibras colágenas; as alterações histopatológicas e a presença ou ausência de solução de continuidade na mucosa. Concluiu-se que foi encontrada maior estenose nas anastomoses confeccionadas com o anel biofragmentável, não havendo repercussão ou alteração significativa do ponto de vista funcional. Ambas as anastomoses suportaram pressões intraluminares acima de 300 mmHg sem se romperem. A espessura da parede junto às anastomoses foi maior naquelas em que se utilizou o anel biofragmentável, o que também não teve nenhuma repercussão funcional, e ambas as técnicas utilizadas mostraram-se seguras na confecção de anastomoses término-terminais em intestino grosso de cães
Abstract: Ten half-breed male dogs were submitted to laparotomy, with intra-operative cleaning of intestinal content, and transverse colon section 10 and 20 em from the ileocolic transition respectival1y. The extremes were then anastomosed, by using the technique of suture with separate seromuscu1ar stiches and overpositioning of the extremes through the use of 4.0 polygluconate threads at proximal anastomoses. The technique ofsutureless compression was used in the distal, with the use of biofragmental anastomosis ring (BAR). The dogs were kept under clinica1 observation during a 30-day-period, after which they were again anesthesized, and then sacrificed, for the removal of the colon segment that contained both anastomosis. Analysis of the macroscopica1 alterations noticed during peritoneal cavity inspection was done, and comparison made between stenosis index, anastomosis resistance to gaseous insufflation and surface aspects. Through microscopic analysis, border coaptation was verified; wal1 thickness; leveI of tissue necrosis; inflammatory reaction, fiberblasts proliferation; formation of colagen fibers; histopathologica1 alterations and the presence or absence of continuity solution in the mucosa. The conclusion was that more stenosis was found in anastomoses with biofragmental anastomosis ring, with no repercussion or significant alteration from the functional point of view. Both ariastomoses tolerated intraluminar pressure above 300 mmHg without rupture. The wall thickness near the anastomoses was higher among those that used the biofragmental anastomosis ring, which also did not present any functional repercussion. Both techniques used were reliable in the making of termino-terminal anastomoses in the bowels of dogs
Mestrado
Mestre em Cirurgia