Digital Workflows and Material Sciences in Dental Medicine

The trend of digitalization is an omnipresent phenomenon nowadays – in social life and in the dental community. Advancement in digital technology has fostered research into new dental materials for the use of these workflows, particularly in the field of prosthodontics and oral implantology.CAD/CAM-technology has been the game changer for the production of tooth-borne and implant-supported (monolithic) reconstructions: from optical scanning, to on-screen designing, and rapid prototyping using milling or 3D-printing. In this context, the continuous development and speedy progress in digital workflows and dental materials ensure new opportunities in dentistry.The objective of this Special Issue is to provide an update on the current knowledge with state-of-the-art theory and practical information on digital workflows to determine the uptake of technological innovations in dental materials science. In addition, emphasis is placed on identifying future research needs to manage the continuous increase in digitalization in combination with dental materials and to accomplish their clinical translation.This Special Issue welcomes all types of studies and reviews considering the perspectives of the various stakeholders with regard to digital dentistry and dental materials

Advanced software techniques for space shuttle data management systems Final report

Airborne/spaceborn computer design and techniques for space shuttle data management system

Research reports: The 1980 NASA/ASEE Summer Faculty Fellowship Program

The Summer Faculty Fellowship Research Program objectives are: to further the professional knowledge of qualified engineering and science faculty members; to stimulate an exchange of ideas between participants and NASA; to enrich and refresh the research and teaching activities of participants and institutions; and to contribute to the research objectives at the NASA centers. The Faculty Fellows engaged in research projects commensurate with their interests and background and worked in collaboration with a NASA/MSFC colleague

Detailed Case Studies

Wireless body area networks (WBANs) are one of the key technologies that support the development of pervasive health monitoring (remote patient monitoring systems), which has attracted more attention in recent years. These WBAN applications requires stringent security requirements as they are concerned with human lives. In the recent scenario of the corona pandemic, where most of the healthcare providers are giving online services for treatment, DDoS attacks become the major threats over the internet. This chapter particularly focusses on detection of DDoS attack using machine learning algorithms over the healthcare environment. In the process of attack detection, the dataset is preprocessed. After preprocessing the dataset, the cleaned dataset is given to the popular classification algorithms in the area of machine learning namely, AdaBoost, J48, k-NN, JRip, Random Committee and Random Forest classifiers. Those algorithms are evaluated independently and the results are recorded. Results concluded that J48 outperform with accuracy of 99.98% with CICIDS dataset and random forest outperform with accuracy of 99.917, but it takes the longest model building time. Depending on the evaluation performance the appropriate classifier is selected for further DDoS detection at real-time

Matrixfreie voxelbasierte Finite-Elemente-Methode für Materialien mit komplizierter Mikrostruktur

Modern image detection techniques such as micro computer tomography (μCT), magnetic resonance imaging (MRI) and scanning electron microscopy (SEM) provide us with high resolution images of the microstructure of materials in a non-invasive and convenient way. They form the basis for the geometrical models of high-resolution analysis, so called image-based analysis. However especially in 3D, discretizations of these models reach easily the size of 100 Mill. degrees of freedoms and require extensive hardware resources in terms of main memory and computing power to solve the numerical model. Consequently, the focus of this work is to combine and adapt numerical solution methods to reduce the memory demand first and then the computation time and therewith enable an execution of the image-based analysis on modern computer desktops. Hence, the numerical model is a straightforward grid discretization of the voxel-based (pixels with a third dimension) geometry which omits the boundary detection algorithms and allows reduced storage of the finite element data structure and a matrix-free solution algorithm. This in turn reduce the effort of almost all applied grid-based solution techniques and results in memory efficient and numerically stable algorithms for the microstructural models. Two variants of the matrix-free algorithm are presented. The efficient iterative solution method of conjugate gradients is used with matrix-free applicable preconditioners such as the Jacobi and the especially suited multigrid method. The jagged material boundaries of the voxel-based mesh are smoothed through embedded boundary elements which contain different material information at the integration point and are integrated sub-cell wise though without additional boundary detection. The efficiency of the matrix-free methods can be retained.Moderne bildgebende Verfahren wie Mikro-Computertomographie (μCT), Magnetresonanztomographie (MRT) und Rasterelektronenmikroskopie (SEM) liefern nicht-invasiv hochauflösende Bilder der Mikrostruktur von Materialien. Sie bilden die Grundlage der geometrischen Modelle der hochauflösenden bildbasierten Analysis. Allerdings erreichen vor allem in 3D die Diskretisierungen dieser Modelle leicht die Größe von 100 Mill. Freiheitsgraden und erfordern umfangreiche Hardware-Ressourcen in Bezug auf Hauptspeicher und Rechenleistung, um das numerische Modell zu lösen. Der Fokus dieser Arbeit liegt daher darin, numerische Lösungsmethoden zu kombinieren und anzupassen, um den Speicherplatzbedarf und die Rechenzeit zu reduzieren und damit eine Ausführung der bildbasierten Analyse auf modernen Computer-Desktops zu ermöglichen. Daher ist als numerisches Modell eine einfache Gitterdiskretisierung der voxelbasierten (Pixel mit der Tiefe als dritten Dimension) Geometrie gewählt, die die Oberflächenerstellung weglässt und eine reduzierte Speicherung der finiten Elementen und einen matrixfreien Lösungsalgorithmus ermöglicht. Dies wiederum verringert den Aufwand von fast allen angewandten gitterbasierten Lösungsverfahren und führt zu Speichereffizienz und numerisch stabilen Algorithmen für die Mikrostrukturmodelle. Es werden zwei Varianten der Anpassung der matrixfreien Lösung präsentiert, die Element-für-Element Methode und eine Knoten-Kanten-Variante. Die Methode der konjugierten Gradienten in Kombination mit dem Mehrgitterverfahren als sehr effizienten Vorkonditionierer wird für den matrixfreien Lösungsalgorithmus adaptiert. Der stufige Verlauf der Materialgrenzen durch die voxelbasierte Diskretisierung wird durch Elemente geglättet, die am Integrationspunkt unterschiedliche Materialinformationen enthalten und über Teilzellen integriert werden (embedded boundary elements). Die Effizienz der matrixfreien Verfahren bleibt erhalten

Point spread function estimation of solar surface images with a cooperative particle swarm optmization on GPUS

Orientador : Prof. Dr. Daniel WeingaertnerDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 21/02/3013Bibliografia : fls. 81-86Resumo: Apresentamos um método para a estimativa da função de espalhamento pontual (PSF) de imagens de superfície solar obtidas por telescópios terrestres e corrompidas pela atmosfera. A estimativa e feita obtendo-se a fase da frente de onda usando um conjunto de imagens de curta exposto, a reconstrucão de granulado optico do objeto observado e um modelo PSF parametrizado por polinómios de Zernikes. Estimativas da fase da frente de onda e do PSF sao computados atraves da minimizacao de uma funcao de erro com um metodo de otimizacão cooperativa por nuvens de partículas (CPSO), implementados em OpenCL para tirar vantagem do ambiente altamente paralelo Um metodo de calibracao e apresentado para ajustar os parâmetros do que as unidade de processamento gráfico (GPU) provem. algoritmo para resultados de baixo custo, resultando em solidas estimativas tanto para imagens de baixa frequencia quanto para imagens de alta frequencia. Os resultados mostram que o metodo apresentado possui râpida convergencia e e robusto a degradacao causada por ruídos. Experimentos executados em uma placa NVidia Tesla C2050 computaram 100 PSFs com 50 polinómios de Zernike em " 36 minutos. Ao aumentar-se o námero de coeficientes de Zernike dez vezes, de 50 para 500, o tempo de execucão aumentou somente 17%, o que demonstra que o algoritmo proposto e pouco afetado pelo numero de Zernikes utilizado.Abstract: We present a method for estimating the point spread function (PSF) of solar surface images acquired from ground telescopes and degraded by atmosphere. The estimation is done by retrieving the wavefront phase using a set of short exposures, the speckle reconstruction of the observed object and a PSF model parametrized by Zernike polynomials. Estimates of the wavefront phase and the PSF are computed by minimizing an error function with a cooperative particle swarm optimization method (CPSO), implemented in OpenCL to take advantage of highly parallel graphical processing units (GPUs). A calibration method is presented to adjust the algorithm parameters for low cost results, providing solid estimations for both low frequency and high frequency images. Results show that the method has a fast convergence and is robust to noise degradation. Experiments run on an NVidia Tesla C2050 were able to compute 100 PSFs with 50 Zernike polynomials in " 36 minutes. The increase on the number of Zernike coefficients tenfold, from 50 to 500, caused the increase of 17% on the execution time, showing that the proposed algorithm is only slightly affected by the number of Zernikes used

SIMULATION OF PROPPANT TRANSPORT IN HYDRAULIC AND NATURAL FRACTURES USING A COUPLED CFD-DEM METHOD

Understanding proppant transport is critically important in designing effective stimulation systems for low-permeability reservoirs, as it leads to better estimates of the propped fracture dimensions and stimulated reservoir volume. Existing models mostly represent proppant as a continuous fluid phase. This assumption is valid for the conventional fracturing designs, where high viscosity fluid (e.g., cross-linking gels) are used as the carrier fluid. Current fracturing designs mostly use low viscosity fluids (e.g., slick water). As a result, proppants behave more like discrete particles and less like a continuous fluid phase. Existing proppant transport models assume a single planar fracture as the main representation of the geometry of fractures, but the geometry of the subsurface fracture networks is much more complex. In this study I couple computational fluid dynamics with the discrete element method (CFD-DEM) to simulate proppant transport in a complex fracture network. The coupled simulator enables the explicit modeling of the motion of individual particles and offers a more accurate representation of the complex interactions between proppant particles, fracturing fluids, and fracture walls. To calibrate the numerical model, I first conducted validation simulations that imitated a particle settling test, a particle collision test and a laboratory proppant transport experiment. Through scoping calculations, I determined the correct drag force model and matched the model predictions with existing analytical solutions and experimental data for a wide range of flow regimes, including three different sizes of proppants (20-30 mesh, 30-40mesh and 50-70 mesh) in two types of fluids (water and oil). In the main component of my study, I built multiple 3-dimentional fracture network models, which include one baseline vertical fracture model, three dipping fracture models, two hydraulic fracture-natural fracture (HF-NF) intersection models (T-shaped and Z-shaped) and, finally, a multi-cluster horizontal wellbore model. In the baseline vertical fracture model, the simulation results show that the flow regime of proppant (suspension or bedload transport) plays a critical role in determining the proppant advance and distribution in the fracture. Higher fluid velocities lead to a larger suspension transport region and a higher proppant placement efficiency in the hydraulic fractures. In the dipping fracture models, my results show that decreasing the dipping angle increases the proppant placement efficiency. In the T-shaped HF-NF intersection model, I observed significantly better proppant placement in the NF when proppants are in the suspension transport regime. In the Z-shaped HF-NF intersection model, my study identified two parameters that are critical for estimating the occurrence of proppant bridging: the proppant concentration (Cp) and the ratio between the secondary fracture aperture and the proppant diameter (Rfp). At a fixed value of Rfp, continuous transport of proppant is possible when Cp is lower than a threshold value. Based on this determination, I use Rfp and Cp to propose a blocking criterion correlation. Lastly, in my multi-cluster wellbore model, I experimented with various pumping strategies and computed the proppant and fluid distribution at each cluster. By comparing the influence of injection rate, I discussed potential strategies to achieve a better (more even) proppant distribution at the different clusters

Design/cost tradeoff studies. Appendix A. Supporting analyses and tradeoffs, book 2. Earth Observatory Satellite system definition study (EOS)

Attitude reference systems for use with the Earth Observatory Satellite (EOS) are described. The systems considered are fixed and gimbaled star trackers, star mappers, and digital sun sensors. Covariance analyses were performed to determine performance for the most promising candidate in low altitude and synchronous orbits. The performance of attitude estimators that employ gyroscopes which are periodically updated by a star sensor is established by a single axis covariance analysis. The other systems considered are: (1) the propulsion system design, (2) electric power and electrical integration, (3) thermal control, (4) ground data processing, and (5) the test plan and cost reduction aspects of observatory integration and test

A study of style and techniques in the music of Elisabeth Lutyens.

In 2 volsSIGLEAvailable from British Library Document Supply Centre- DSC:D95625 / BLDSC - British Library Document Supply CentreGBUnited Kingdo