Objetivo. Esta revisão sistemática com metanálise investigou se o protocolo de carga imediata tem mais desvantagens clínicas do que o protocolo de carga precoce para implantes dentários individuais em termos de perda óssea marginal e taxa de sobrevivência de coroas de implantes unitários. Material e métodos: Dois revisores realizaram uma pesquisa avançada de banco de dados eletrônico, sem restrição de idioma ou data, no Medline / PubMed, Embase e na Biblioteca Cochrane até maio de 2016. Os estudos foram escolhidos por título e resumo para triagem, de acordo com os seguintes critérios de inclusão: estudos de implantes dentários; estudos de coorte (prospectivos e retrospectivos) e estudos clínicos aleatorizados; amostras envolvendo pacientes parcialmente desdentados; implantes com carga imediata; carregamento precoce de implantes; e n>=10. Após a leitura do texto completo os artigos foram excluídos de acordo com os seguintes critérios: 1) estudos sem implantes dentários de titânio; 2) revisão sistemática, descrição de técnica, intervenções, protocolos, estudos in vitro e relato de casos; 3) estudos sem implantes com carga imediata; 4) estudos sem implantes com carga precoce; 5) amostras menores do que 10 pacientes; 6) implantes unidos; 7) grupos isolados (pacientes com diabetes, cardiopatas, pacientes com bruxismo ou osso irradiado); 8) acompanhamento menor do que 6 meses; 9) estudos sem taxa de sobrevida; 10) estudos sem acompanhamento da perda óssea marginal; 11) taxa de desistência maior do que 30%. Resultados. Dos 5710 estudos inicialmente identificados, 5 preencheram os critérios de inclusão. Uma metanálise que gerou diferença de risco (DR) e diferença média (DM) com um intervalo de confiança de 95% (IC 95%) foi realizada. Os estudos incluídos não mostraram diferenças significativas entre os protocolos de carga precoce e imediata em coroas de implante unitário em relação à taxa de sobrevivência em 1 e 3 anos (RD -0,00, IC 95% -0,04 a 0,04; P = 0,990 por 1 ano e P = 0,980 por 3 anos), ou perda óssea marginal em 1 (DM 0,09, 95% IC -0,02 a 0,19; P = 0,110) e 3 anos (DM -0,23, 95% IC -0,47 a 0,01; P =, 060 ). Conclusões: Esta revisão sistemática não mostrou diferenças significativas entre os protocolos de carga inicial e imediata em coroas de implante unitário em relação à taxa de sobrevivência ou perda óssea marginal em 1 ou 3 anos. / Purpose. This systematic review and meta-analysis investigated whether the immediate loading protocol has more clinical disadvantages than the early loading protocol for single dental implants in terms of the marginal bone loss and survival rate of single implant crowns. Material and methods. Two reviewers conducted an advanced electronic database search, with no language or date restriction, in Medline/PubMed, Embase, and the Cochrane Library up to May 2016. Studies were chosen by title and abstract for screening in accordance with the following inclusion criteria: dental implants studies; cohort studies (prospective and retrospective) and randomized controlled trials; samples involving partially edentulous patients; immediate loading implants; early loading implants; and n>=10. Results. Of the 5710 studies initially identified, 5 fulfilled the inclusion criteria. A meta-analysis yielding risk difference (RD) and mean difference (MD) with a confidence interval of 95% (95% CI) was performed. The included trials showed no significant differences between early and immediate loading protocols in single implant crowns with regard to survival rate at 1 and 3 years (RD -0.00, 95% CI -0.04 to 0.04; P=.990 for 1 year and P=.980 for 3 years), or marginal bone loss at 1 (MD 0.09, 95% CI -0.02 to 0.19; P=.110) and 3 years (MD -0.23, 95% CI -0.47 to 0.01; P=.060). Conclusions. This systematic review showed no significant differences between early and immediate loading protocols in single implant crowns with regard to survival rate or marginal bone loss at 1 or 3 years.

Atualmente, a Onion-tree [Carélo et al., 2009] é o método de acesso métrico baseado em memória primária mais eficiente para pesquisa por similaridade disponível na literatura. Ela indexa dados complexos por meio da divisão do espaço métrico em regiões (ou seja, subespaços) disjuntas, usando para isso dois pivôs por nó. Para prover uma boa divisão do espaço métrico, a Onion-tree introduz as seguintes características principais: (i) procedimento de expansão, o qual inclui um método de particionamento que controla o número de subespaços disjuntos gerados em cada nó; (ii) técnica de substituição, a qual pode alterar os pivôs de um nó durante operações de inserção baseado em uma política de substituição que garante uma melhor divisão do espaço métrico, independente da ordem de inserção dos elementos; e (iii) algoritmos para a execução de consultas por abrangência e aos k-vizinhos mais próximos, de forma que esses tipos de consulta possam explorar eficientemente o método de particionamento da Onion-tree. Entretanto, a Onion-tree apenas oferece funcionalidades voltadas à inserção dos dados um-a-um em sua estrutura. Ela não oferece, portanto, uma operação de bulk-loading que construa o índice considerando todos os elementos do conjunto de dados de uma única vez. A principal vantagem dessa operação é analisar os dados antecipadamente para garantir melhor particionamento possível do espaço métrico. Com isto, a carga inicial de grandes volumes de dados pode ser melhor realizada usando a operação de bulk-loading. Este projeto de mestrado visa suprir a falta da operação de bulk-loading para a Onion-tree, por meio da proposta de algoritmos que exploram as características intrínsecas desse método de acesso métrico. No total, são propostos três algoritmos de bulk-loading, denominados GreedyBL, SampleBL e HeightBL, os quais utilizam respectivamente as seguintes abordagens: gulosa, amostragem e de estimativa da altura do índice. Testes experimentais realizados sobre conjuntos de dados com volume variando de 2.536 a 102.240 imagens e com dimensionalidade variando de 32 a 117 dimensões mostraram que os algoritmos propostos introduziram vantagens em relação à estrutura criada pelo algoritmo de inserção um-a-um da Onion-tree. Comparado com a inserção um-a-um, o tamanho do índice foi reduzido de 9% até 88%. Em consultas por abrangência, houve redução de 16% até 99% no número de cálculos de distância e de 9% a 99% no tempo gasto em relação à inserção. Em consultas aos k-vizinhos mais próximos, houve redução de 13% a 86% em número de cálculos de distância e de 9% até 63% no tempo gasto / The main-memory Onion-tree [Carélo et al., 2009] is the most efficient metric access method to date. It indexes complex data by dividing the metric space into several disjoint regions (i.e. subspaces) by using two pivots per node. To provide a good division of the metric space, the Onion-tree introduces the following characteristics: (i) expansion procedure, which provides a partitioning method that controls the number of disjoint subspaces generated at each node; (ii) replacement technique, which can replace the pivots of a leaf node during insert operations based on a replacement policy that ensures a better division of the metric space, regardless of the insertion order of the elements; and (iii) algorithms for processing range and k-NN queries, so that these types of query can efficiently use the partitioning method of the Onion-tree. However, the Onion-tree only performs element-by-element insertions into its structure. Another important issue is the mass loading technique, called bulk-loading, which builds the index considering all elements of the dataset at once. This technique is very useful in the case of reconstructing the index or inserting a large number of elements simultaneously. Despite the importance of this technique, to the best of our knowledge, there are not in the literature bulk-loading algorithms for the Onion-tree. In this masters thesis, we fill this gap. We propose three algorithms for bulk-loading Onion-trees: the GreedyBL algorithm, the SampleBL algorithm and the HeightBL algorithm. These algorithms are based on the following approaches, respectively: greedy, sampling and estime height of the index. Performance tests with real-world data with different volumes (ranging from 2,536 to 102,240 images) and different dimensionalities (ranging from 32 to 117 dimensions) showed that the indices produced by the proposed algorithms are very compact. Compared with the element-by-element insertion, the size of the index reduced from 9% up to 88%. The proposed algorithms also provided a great improvement in query processing. They required from 16% up to 99% less distance calculations and were from 9% up to 99% faster than the element-by-element insertion to process range queries. Also, they required from 13% up to 86% less distance calculations and were from 9% up to 63% faster than the element-by-element insertion to process k-NN queries

This thesis investigates the feasibility of loading silicone hydrogel (SiHy) contact lenses with two different hydrophobic therapeutics, latanoprost and DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine), for treatment of glaucoma and hyperemia respectively. The two methods of loading were 1) thermal loading in an aqueous medium and 2) convective loading in a solution of n-propanol. Dailies Total1® lenses prepared in this manner were tested for their loading and their release into artificial tears. Continuous release over 1-4 days at therapeutic levels is achievable from thermal loading of DMPC, convective loading of DMPC, and convective loading of latanoprost. The DMPC loading processes can be naturally integrated into standard manufacturing lines for Dailies Total1®. Both DMPC and latanoprost release at rates proportional to the amount loaded into a contact lens. Latanoprost loads into a contact lens strictly proportionally to the loading concentration and the time of loading. The convective loading step represents a significant improvement on both the time of loading (reduced from days to minutes) and the loading capacity of silicone hydrogel contact lenses. This thesis also compares the loading and release of latanoprost in the convective loading procedure using the SiHy contact lenses of Acuvue Advance® (Johnson & Johnson Vision Care, Jacksonville, FL) , Air Optix® (Alcon, Copenhagen, Denmark), Biofinity® (CooperVision), PureVision® (Bausch & Lomb), and Dailies Total1® (Alcon), and the polyHEMA lens, SofLens 38® (Bausch & Lomb), finding that silicone hydrogels load an order of magnitude more drug than the polyHEMA lens and release into artificial tears for an order of magnitude longer. Overall, these experiments provide a quantitative understanding of the dynamics of loading and release for both DMPC and latanoprost.

<p>Kunskap om grundvattenbildningen är nödvändig för att man ska kunna förutsäga konsekvenserna av grundvattenuttag och underjordsbyggande. Grundvattenbildningen i berggrunden är dock svår att uppskatta. Syftet med avhandlingen var att öka förståelsen av grundvattenbildningen i kristallin berggrund, att undersöka hur grundvattenbildningen ska uppskattas samt att utveckla nya modeller för att beskriva grundvattenbildningen. Studien grundades på tre angreppssätt: grundvattendatering med freoner (CFC), geohydrauliska observationer och matematisk modellering.</p><p>Koncentrationerna av CFC-11 och CFC-113 befanns vara låga i det undersökta berggrundvattnet, vilket i kombination med låga syrgashalter tyder på anaerob nedbrytning. Koncentrationerna av CFC-12 och tritium överensstämde ganska väl, vilket betyder att den skenbara åldern kan vara den sanna åldern. Resultaten tyder på att CFC-datering inte är pålitlig i skogsmiljöer med finkornigt jordtäcke.</p><p>Vid nederbörd observerades ett snabbt gensvar i den hydrauliska potentialen i den studerade bergakviferen, trots det 10 m mäktiga moräntäcket. En avsevärd del av de observerade potentialvariationerna befanns vara belastningseffekter, som inte innebar någon magasinsförändring eller något vattenflöde. Berggrundens belastningseffektivitet uppskattades, ur potentialens svar på lufttrycksförändringar, till 0,95. Ytbelastningen beräknades från mätningar av lufttryck, vatten i jordtäcket och snö. Omkring 20 % av årstidsvariationen hos den hydrauliska potentialen uppskattades bero på enbart belastningsförändringar. En enkel begreppsmässig modell kunde användas för att simulera den observerade hydrauliska potentialen. För att beskriva enskilda grundvattenbildningstillfällen på bästa sätt var det nödvändigt att ta hänsyn till effekten av ytbelastningen.</p><p>Numeriska experiment gjordes med en modell av en jord–bergprofil. När berget modellerades som ett heterogent kontinuum bildades omättade zoner i berget vid stora hydrauliska gradienter. Fenomenet uppträdde i områden där låggenomsläppliga zoner låg uppströms höggenomsläppliga zoner, och ledde till minskad hydraulisk konduktivitet i berget.</p> / <p>Knowledge about the groundwater recharge is essential for the prediction of impacts of groundwater withdrawal and underground construction. Recharge in the bedrock is, however, difficult to estimate. The objectives of this thesis were to increase the understanding of groundwater recharge in crystalline bedrock, to investigate how the recharge could be estimated, and to develop new models to describe the recharge. The study was based on three approaches: groundwater dating using chlorofluorocarbons (CFCs), geohydraulic field measurements, and mathematical modelling.</p><p>Low concentrations of CFC-11 and CFC-113 were found in the bedrock groundwater, which in combination with low dissolved-oxygen levels indicated anaerobe degradation. The CFC-12 and tritium concentrations agreed fairly well, which means that apparent ages could be true ages. The results suggest that CFC dating may not be reliable at forested, humid sites covered by fine-grained soil.</p><p>A quick response in hydraulic head to precipitation was observed in the studied bedrock, despite the 10-m thick till cover. A substantial portion of observed head variations was found to be loading effects, involving no storage changes or water flow. The loading efficiency of the bedrock was estimated, from the air-pressure response, to be 0.95. The surface loading was calculated from measurements of air pressure, water in the soil, and snow. About 20% of the seasonal variation of the hydraulic head was estimated to be related to loading changes only. A simple conceptual model could be used to simulate the observed hydraulic heads. The loading effect had to be included to properly describe individual recharge events.</p><p>Numerical experiments were performed with a soil–bedrock profile. When the rock was modelled as a heterogeneous continuum, unsaturated zones developed at high hydraulic gradients. The phenomenon appeared in areas where low-conductive zones were located upstream of high-conductive zones, decreasing the effective hydraulic conductivity of the material.</p>

Kunskap om grundvattenbildningen är nödvändig för att man ska kunna förutsäga konsekvenserna av grundvattenuttag och underjordsbyggande. Grundvattenbildningen i berggrunden är dock svår att uppskatta. Syftet med avhandlingen var att öka förståelsen av grundvattenbildningen i kristallin berggrund, att undersöka hur grundvattenbildningen ska uppskattas samt att utveckla nya modeller för att beskriva grundvattenbildningen. Studien grundades på tre angreppssätt: grundvattendatering med freoner (CFC), geohydrauliska observationer och matematisk modellering. Koncentrationerna av CFC-11 och CFC-113 befanns vara låga i det undersökta berggrundvattnet, vilket i kombination med låga syrgashalter tyder på anaerob nedbrytning. Koncentrationerna av CFC-12 och tritium överensstämde ganska väl, vilket betyder att den skenbara åldern kan vara den sanna åldern. Resultaten tyder på att CFC-datering inte är pålitlig i skogsmiljöer med finkornigt jordtäcke. Vid nederbörd observerades ett snabbt gensvar i den hydrauliska potentialen i den studerade bergakviferen, trots det 10 m mäktiga moräntäcket. En avsevärd del av de observerade potentialvariationerna befanns vara belastningseffekter, som inte innebar någon magasinsförändring eller något vattenflöde. Berggrundens belastningseffektivitet uppskattades, ur potentialens svar på lufttrycksförändringar, till 0,95. Ytbelastningen beräknades från mätningar av lufttryck, vatten i jordtäcket och snö. Omkring 20 % av årstidsvariationen hos den hydrauliska potentialen uppskattades bero på enbart belastningsförändringar. En enkel begreppsmässig modell kunde användas för att simulera den observerade hydrauliska potentialen. För att beskriva enskilda grundvattenbildningstillfällen på bästa sätt var det nödvändigt att ta hänsyn till effekten av ytbelastningen. Numeriska experiment gjordes med en modell av en jord–bergprofil. När berget modellerades som ett heterogent kontinuum bildades omättade zoner i berget vid stora hydrauliska gradienter. Fenomenet uppträdde i områden där låggenomsläppliga zoner låg uppströms höggenomsläppliga zoner, och ledde till minskad hydraulisk konduktivitet i berget. / Knowledge about the groundwater recharge is essential for the prediction of impacts of groundwater withdrawal and underground construction. Recharge in the bedrock is, however, difficult to estimate. The objectives of this thesis were to increase the understanding of groundwater recharge in crystalline bedrock, to investigate how the recharge could be estimated, and to develop new models to describe the recharge. The study was based on three approaches: groundwater dating using chlorofluorocarbons (CFCs), geohydraulic field measurements, and mathematical modelling. Low concentrations of CFC-11 and CFC-113 were found in the bedrock groundwater, which in combination with low dissolved-oxygen levels indicated anaerobe degradation. The CFC-12 and tritium concentrations agreed fairly well, which means that apparent ages could be true ages. The results suggest that CFC dating may not be reliable at forested, humid sites covered by fine-grained soil. A quick response in hydraulic head to precipitation was observed in the studied bedrock, despite the 10-m thick till cover. A substantial portion of observed head variations was found to be loading effects, involving no storage changes or water flow. The loading efficiency of the bedrock was estimated, from the air-pressure response, to be 0.95. The surface loading was calculated from measurements of air pressure, water in the soil, and snow. About 20% of the seasonal variation of the hydraulic head was estimated to be related to loading changes only. A simple conceptual model could be used to simulate the observed hydraulic heads. The loading effect had to be included to properly describe individual recharge events. Numerical experiments were performed with a soil–bedrock profile. When the rock was modelled as a heterogeneous continuum, unsaturated zones developed at high hydraulic gradients. The phenomenon appeared in areas where low-conductive zones were located upstream of high-conductive zones, decreasing the effective hydraulic conductivity of the material.

Fatigue crack growth behavior of AA7050 T7451 aluminum alloy under mode II loading condition in two orientations was investigated. Compact shear specimens were prepared in TL and LT directions. A loading frame for mode II type of loading was manufactured. Using the loading frame and the specimen, KIIC values and mode II fatigue crack growth rates were calculated. Fractographic analysis of the fracture surfaces of both mode II fracture toughness test specimens and mode II fatigue crack growth test specimens were done to examine the effects of mode II load. KIIC values were measured between 1.3 and 1.5 times the KIC values for this alloy. As for mode II fatigue crack growth rates, TL orientation shows the highest mode II fatigue crack growth resistance.

Whether you are in industrial manufacturing striving to optimize your supply chain, international or domestic carrier committed to lower your operational costs, retailer dedicated to run your distribution network more efficiently, or anywhere else where the words "cargo", "freight", "shipment" are in your business language, automated load planning and optimization will significantly improve your business process. While the concept of computerized simulation of 3D load building is not new, with some companies offering software solutions for "virtual" loading, no one has a single product that is capable to handle complex variety of business rules and constraints of the modern transportation industry. We are analyzing the problems related with 3D box loading and then to analyze existing 3D load building systems. After accumulating all analyzes data we are having enough experience to create our own algorithm. And we did it! We create 3D box loading algorithm witch is fast and accurate and 3D box loading system which is using this new algorithm. To ensure that we succeeded we compare this new system with existing 3D box loading software to make sure that it’s really useful for solving logistic problems. After testing we are sure that we made a big job and we have created system, which can compete with the logistic IT leaders made solutions.

Several studies were undertaken by various investigators during the last five decades to better understand the engineering behaviour of unsaturated soils. These studies are justified as more than 33% of soils worldwide are found in either arid or semi-arid regions with evaporation losses exceeding water infiltration. Due to this reason, the natural ground water table in these regions is typically at a greater depth and the soil above it is in a state of unsaturated conditions. Foundations of structures such as the housing subdivisions, multi-storey buildings, bridges, retaining walls, silos, and other infrastructure constructed in these regions in sandy soils are usually built within the unsaturated zone (i.e., vadose zone). Limited studies are reported in the literature to understand the influence of capillary stresses (i.e., matric suction) on the bearing capacity, settlement and liquefaction potential of unsaturated sands. The influence of matric suction in the unsaturated zone of the sandy soils is ignored while estimating or evaluating bearing capacity, settlement and liquefaction resistance in conventional engineering practice. The focus of the research presented in the thesis has been directed towards better understanding of these aspects and providing rational and yet simple tools for the design of shallow foundations (i.e., footings) in sands under both static and dynamic loading conditions. Terzaghi (1943) or Meyerhof (1951) equations for bearing capacity and Schmertmann et al. (1978) equation for settlement are routinely used by practicing engineers for sandy soils based on saturated soil properties. The assumption of saturated conditions leads to conservative estimates for bearing capacity; however, neglecting the influence of capillary stresses contributes to unreliable estimates of settlement or differential settlement of footings in unsaturated sands. There are no studies reported in the literature on how capillary stresses influence liquefaction, bearing capacity and settlement behavior in earthquake prone regions under dynamic loading conditions. An extensive experimental program has been undertaken to study these parameters using several specially designed and constructed equipment at the University of Ottawa. The influence of matric suction, confinement and dilation on the bearing capacity of model footings in unsaturated sand was determined using the University of Ottawa Bearing Capacity Equipment (UOBCE-2011). Several series of plate load tests (PLTs) were carried out on a sandy soil both under saturated and unsaturated conditions. Based on these studies, a semi-empirical equation has been proposed for estimating the variation of bearing capacity with respect to matric suction. The saturated shear strength parameters and the soil water characteristic curve (SWCC) are required for using the proposed equation. This equation is consistent with the bearing capacity equation originally proposed by Terzaghi (1943) and later extended by Meyerhof (1951) for saturated soils. Chapter 2 provides the details of these studies. The cone penetration test (CPT) is conventionally used for estimating the bearing capacity of foundations because it is simple and quick, while providing continuous records with depth. In this research program, a cone penetrometer was specially designed to investigate the influence of matric suction on the cone resistance in a controlled laboratory environment. Several series of CPTs were conducted in sand under both saturated and unsaturated conditions. Simple correlations were proposed from CPTs data to relate the bearing capacity of shallow foundations to cone resistance in saturated and unsaturated sands. The details of these studies are presented and summarized in Chapter 3. Standard penetration tests (SPTs) and PLTs were conducted in-situ sand deposit at Carp region in Ottawa under both saturated and unsaturated conditions. The test results from the SPTs and PLTs at Carp were used along with other data from the literature for developing correlations for estimating the bearing capacity of both saturated and unsaturated sands. The proposed SPT-CPT-based technique is simple and reliable for estimation of the bearing capacity of footings in sands. Chapter 4 summarizes the details of these investigations. Empirical relationships were proposed using the CPTs data to estimate the modulus of elasticity of sands for settlement estimation of footings in both saturated and unsaturated sands. This was achieved by modifying the Schmertmann et al. (1978) equation, which is conventionally used for settlement estimations in practice. Comparisons are provided between the three CPT-based methods that are commonly used for settlement estimations in practice and the proposed method for seven large scale footings in sandy soils. The results of the comparisons show that the proposed method provides better estimations for both saturated and unsaturated sands. Chapter 5 summarizes the details of these studies. A Flexible Laminar Shear Box (FLSB of 800-mm3 in size) was specially designed and constructed to simulate and better understand the behaviour of model surface footing under seismic loads taking account of the influence of matric suction in an unsaturated sandy soil. The main purpose of using the FLSB is to simulate realistic in-situ soils behaviour during earthquake ground shaking. The FLSB test setup with model footing was placed on unidirectional 1-g shake table (aluminum platform of 1000-mm2 in size) during testing. The resistance of unsaturated sand to deformations and liquefaction under seismic loads was investigated. The results of the study show that matric suction offers significant resistance to liquefaction and settlement of footings in sand. Details of the equipment setup, test procedure and results of this study are presented in Chapter 6. Simple techniques are provided in this thesis for estimating the bearing capacity and settlement behaviour of sandy soils taking account of the influence of capillary stresses (i.e., matric suction). These techniques are consistent with the methods used in conventional geotechnical engineering practice. The studies show that even low values of capillary stresses (i.e., 0 to 5 kPa) increases the bearing capacity by two to four folds, and the settlement of footings not only decreases significantly but also offers resistance to liquefaction in sands. These studies are promising and encouraging to use ground improvement techniques; such as capillary barrier techniques to maintain capillary stresses within the zone of influence below shallow foundations. Such techniques, not only contribute to the increase of bearing capacity, they reduce settlement and alleviate problems associated with earthquake effects in sandy soils.

Au cours des 50 dernières années, l’étude du phénomène de liquéfaction de sols sableux saturés ont fait l'objet de nombreuses recherches en laboratoire. La plupart de ces recherches antérieures se sont concentrées sur la liquéfaction de sables propres, en supposant que la présence de fines limite le développement de la surpression interstitielle et donc le risque de liquéfaction. Cependant, les sables sableux naturels se trouvent généralement dans la nature sous la forme d'un mélange de sable et de fines et, l’influence de ces fines sur le risque de liquéfaction de ce type de matériau n'est toujours pas claire. En effet, on trouve des résultats contradictoires, dans la littérature, sur l'effet des particules fines sur le phénomène de liquéfaction des sables. Dans ce contexte, l’objectif principal de ce travail expérimental est de clarifier et de quantifier l’influence des particules fines présentes au sein d’une matrice sableuse sur l’initiation et le développement du phénomène de liquéfaction. On s’est intéressé, en particulier, à la nature des particules fines (plastique/non-plastique), à leur proportion au sein de la matrice, à l’état de compacité de la matrice et à l’état de contrainte initial (état de consolidation). A cet effet, à l'aide d'un nouveau dispositif triaxial servo-hydraulique, une série d'essais monotones et cycliques ont été effectués afin de clarifier cet effet. Les résultats expérimentaux montrent que l'augmentation de la proportion de fines non plastiques augmente la résistance à la liquéfaction du mélange sous chargements monotone et cyclique. Par contre, cette tendance est inversée pour les mélanges qui contiennent des fines plastiques. Enfin, une comparaison a été établie entre le comportement de ces sols sous cisaillement monotone et cyclique non drainé en termes d'évaluation du déclenchement du phénomène d'instabilité et d'autres paramètres mécaniques / Since the last 50 years, the study of the phenomenon of liquefaction of saturated sandy soils has been a topic of extensive laboratory research. Most of the earlier research has focused on the liquefaction of clean sands assuming that the presence of fines resists the development of pore water pressure as well as the risk of liquefaction. However, natural sand is found in nature under the form of a mixture of sand and fines and, the influence of these fines on the liquefaction risk of this type of material is still unclear. In fact, we could find contradictory results in the literature review of the effect of fine particles on the sand liquefaction phenomenon. In this context, the main objective of this study is to clarify and quantify the influence of fine particles (plastic and non-plastic) present in a sandy matrix on the initiation and development of the liquefaction phenomenon .We’ve focused, in particular, on the nature of fine particles (plastic/non-plastic), their proportion in the matrix, the matrix compactness condition and initial stress state (state consolidation). For this purpose, with the aid of a new triaxial servo-hydraulic device, a series of monotonic and cyclic tests were done in order to clarify this effect. Experimental results show that the increase in non-plastic fines increases the resistance to liquefaction of the mixture under both monotonic and cyclic loading. However, this trend is reversed for the mixtures containing plastic fines. Finally a comparison has been established between the behavior of these soils under undrained monotonic and cyclic shearing in terms of evaluation of the initiation of instability phenomenon and other mechanical parameters

Atualmente, a Onion-tree [Carélo et al., 2009] é o método de acesso métrico baseado em memória primária mais eficiente para pesquisa por similaridade disponível na literatura. Ela indexa dados complexos por meio da divisão do espaço métrico em regiões (ou seja, subespaços) disjuntas, usando para isso dois pivôs por nó. Para prover uma boa divisão do espaço métrico, a Onion-tree introduz as seguintes características principais: (i) procedimento de expansão, o qual inclui um método de particionamento que controla o número de subespaços disjuntos gerados em cada nó; (ii) técnica de substituição, a qual pode alterar os pivôs de um nó durante operações de inserção baseado em uma política de substituição que garante uma melhor divisão do espaço métrico, independente da ordem de inserção dos elementos; e (iii) algoritmos para a execução de consultas por abrangência e aos k-vizinhos mais próximos, de forma que esses tipos de consulta possam explorar eficientemente o método de particionamento da Onion-tree. Entretanto, a Onion-tree apenas oferece funcionalidades voltadas à inserção dos dados um-a-um em sua estrutura. Ela não oferece, portanto, uma operação de bulk-loading que construa o índice considerando todos os elementos do conjunto de dados de uma única vez. A principal vantagem dessa operação é analisar os dados antecipadamente para garantir melhor particionamento possível do espaço métrico. Com isto, a carga inicial de grandes volumes de dados pode ser melhor realizada usando a operação de bulk-loading. Este projeto de mestrado visa suprir a falta da operação de bulk-loading para a Onion-tree, por meio da proposta de algoritmos que exploram as características intrínsecas desse método de acesso métrico. No total, são propostos três algoritmos de bulk-loading, denominados GreedyBL, SampleBL e HeightBL, os quais utilizam respectivamente as seguintes abordagens: gulosa, amostragem e de estimativa da altura do índice. Testes experimentais realizados sobre conjuntos de dados com volume variando de 2.536 a 102.240 imagens e com dimensionalidade variando de 32 a 117 dimensões mostraram que os algoritmos propostos introduziram vantagens em relação à estrutura criada pelo algoritmo de inserção um-a-um da Onion-tree. Comparado com a inserção um-a-um, o tamanho do índice foi reduzido de 9% até 88%. Em consultas por abrangência, houve redução de 16% até 99% no número de cálculos de distância e de 9% a 99% no tempo gasto em relação à inserção. Em consultas aos k-vizinhos mais próximos, houve redução de 13% a 86% em número de cálculos de distância e de 9% até 63% no tempo gasto / The main-memory Onion-tree [Carélo et al., 2009] is the most efficient metric access method to date. It indexes complex data by dividing the metric space into several disjoint regions (i.e. subspaces) by using two pivots per node. To provide a good division of the metric space, the Onion-tree introduces the following characteristics: (i) expansion procedure, which provides a partitioning method that controls the number of disjoint subspaces generated at each node; (ii) replacement technique, which can replace the pivots of a leaf node during insert operations based on a replacement policy that ensures a better division of the metric space, regardless of the insertion order of the elements; and (iii) algorithms for processing range and k-NN queries, so that these types of query can efficiently use the partitioning method of the Onion-tree. However, the Onion-tree only performs element-by-element insertions into its structure. Another important issue is the mass loading technique, called bulk-loading, which builds the index considering all elements of the dataset at once. This technique is very useful in the case of reconstructing the index or inserting a large number of elements simultaneously. Despite the importance of this technique, to the best of our knowledge, there are not in the literature bulk-loading algorithms for the Onion-tree. In this masters thesis, we fill this gap. We propose three algorithms for bulk-loading Onion-trees: the GreedyBL algorithm, the SampleBL algorithm and the HeightBL algorithm. These algorithms are based on the following approaches, respectively: greedy, sampling and estime height of the index. Performance tests with real-world data with different volumes (ranging from 2,536 to 102,240 images) and different dimensionalities (ranging from 32 to 117 dimensions) showed that the indices produced by the proposed algorithms are very compact. Compared with the element-by-element insertion, the size of the index reduced from 9% up to 88%. The proposed algorithms also provided a great improvement in query processing. They required from 16% up to 99% less distance calculations and were from 9% up to 99% faster than the element-by-element insertion to process range queries. Also, they required from 13% up to 86% less distance calculations and were from 9% up to 63% faster than the element-by-element insertion to process k-NN queries