Qing, Hai; Mishnaevsky, Leon
2009-01-01
A 3D hierarchical computational model of deformation and stiffness of wood, which takes into account the structures of wood at several scale levels (cellularity, multilayered nature of cell walls, composite-like structures of the wall layers) is developed. At the mesoscale, the softwood cell is...... presented as a 3D hexagon-shape-tube with multilayered walls. The layers in the softwood cell are considered as considered as composite reinforced by microfibrils (celluloses). The elastic properties of the layers are determined with Halpin–Tsai equations, and introduced into mesoscale finite element...
Adaptive Enhancement of 3D Scenes using Hierarchical Registration of Texture-Mapped 3D Models
Ramalingam, Srikumar; Lodha, Suresh
2003-01-01
Adaptive fusion of new information in a 3D urban scene is an important goal to achieve in computer vision, graphics, and visualization. In this work we acquire new image pairs of a scene from closer distances and extract 3D models of successively higher resolutions. We present a new hierarchical approach to register these texture-mapped 3D models with a coarse 3D texture mapped model of an urban scene. First, we use the standard reconstruction algorithm to construct 3D models after establishi...
Resilient 3D hierarchical architected metamaterials.
Meza, Lucas R; Zelhofer, Alex J; Clarke, Nigel; Mateos, Arturo J; Kochmann, Dennis M; Greer, Julia R
2015-09-15
Hierarchically designed structures with architectural features that span across multiple length scales are found in numerous hard biomaterials, like bone, wood, and glass sponge skeletons, as well as manmade structures, like the Eiffel Tower. It has been hypothesized that their mechanical robustness and damage tolerance stem from sophisticated ordering within the constituents, but the specific role of hierarchy remains to be fully described and understood. We apply the principles of hierarchical design to create structural metamaterials from three material systems: (i) polymer, (ii) hollow ceramic, and (iii) ceramic-polymer composites that are patterned into self-similar unit cells in a fractal-like geometry. In situ nanomechanical experiments revealed (i) a nearly theoretical scaling of structural strength and stiffness with relative density, which outperforms existing nonhierarchical nanolattices; (ii) recoverability, with hollow alumina samples recovering up to 98% of their original height after compression to ≥ 50% strain; (iii) suppression of brittle failure and structural instabilities in hollow ceramic hierarchical nanolattices; and (iv) a range of deformation mechanisms that can be tuned by changing the slenderness ratios of the beams. Additional levels of hierarchy beyond a second order did not increase the strength or stiffness, which suggests the existence of an optimal degree of hierarchy to amplify resilience. We developed a computational model that captures local stress distributions within the nanolattices under compression and explains some of the underlying deformation mechanisms as well as validates the measured effective stiffness to be interpreted as a metamaterial property. PMID:26330605
3D surface reconstruction multi-scale hierarchical approaches
Bellocchio, Francesco; Ferrari, Stefano; Piuri, Vincenzo
2012-01-01
3D Surface Reconstruction: Multi-Scale Hierarchical Approaches presents methods to model 3D objects in an incremental way so as to capture more finer details at each step. The configuration of the model parameters, the rationale and solutions are described and discussed in detail so the reader has a strong understanding of the methodology. Modeling starts from data captured by 3D digitizers and makes the process even more clear and engaging. Innovative approaches, based on two popular machine learning paradigms, namely Radial Basis Functions and the Support Vector Machines, are also introduced
3D Computations and Experiments
Couch, R; Faux, D; Goto, D; Nikkel, D
2004-04-05
This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.
Parametrizable cameras for 3D computational steering
Mulder, J.D.; Wijk, J.J. van
1997-01-01
We present a method for the definition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and configure multiple views on his custom 3D interface in an intuitive graphical man
Computer Modelling of 3D Geological Surface
Kodge B. G.
2011-02-01
Full Text Available The geological surveying presently uses methods and tools for the computer modeling of 3D-structures of the geographical subsurface and geotechnical characterization as well as the application of geoinformation systems for management and analysis of spatial data, and their cartographic presentation. The objectives of this paper are to present a 3D geological surface model of Latur district in Maharashtra state of India. This study is undertaken through the several processes which are discussed in this paper to generate and visualize the automated 3D geological surface model of a projected area.
Computer Modelling of 3D Geological Surface
Kodge, B G
2011-01-01
The geological surveying presently uses methods and tools for the computer modeling of 3D-structures of the geographical subsurface and geotechnical characterization as well as the application of geoinformation systems for management and analysis of spatial data, and their cartographic presentation. The objectives of this paper are to present a 3D geological surface model of Latur district in Maharashtra state of India. This study is undertaken through the several processes which are discussed in this paper to generate and visualize the automated 3D geological surface model of a projected area.
Handling Missing Data in the Computation of 3D Affine Transformations
Martisson, Hanna; Bartoli, Adrien; Gaspard, François; Lavest, Jean-Marc
2005-01-01
The reconstruction of rigid scenes from multiple images is a central topic in computer vision. Approaches merging partial 3D models in a hierarchical manner have proven the most eective to deal with large image sequences. One of the key building blocks of these hierarchical approaches is the alignment of two partial 3D models, which requires to express them in the same 3D coordinate frame by computing a 3D transformation. This problem has been well-studied for the cases of 3D models obtained ...
Harbo, Anders La-Cour; Stoustrup, Jakob
2000-01-01
The infra red 3D mouse is a three dimensional input device to a computer. It works by determining the position of an arbitrary object (like a hand) by emitting infra red signals from a number of locations and measuring the reflected intensities. To maximize stability, robustness, and use of bandw......The infra red 3D mouse is a three dimensional input device to a computer. It works by determining the position of an arbitrary object (like a hand) by emitting infra red signals from a number of locations and measuring the reflected intensities. To maximize stability, robustness, and use...
3D Cameras: 3D Computer Vision of Wide Scope
May, Stefan; Pervoelz, Kai; Surmann, Hartmut
2007-01-01
First of all, a short comparison of range sensors and their underlying principles was given. The chapter further focused on 3D cameras. The latest innovations have given a significant improvement for the measurement accuracy, wherefore this technology has attracted attention in the robotics community. This was also the motivation for the examination in this chapter. On this account, several applications were presented, which represents common problems in the domain of autonomous robotics. For...
Practical algorithms for 3D computer graphics
Ferguson, R Stuart
2013-01-01
""A valuable book to accompany any course that mixes the theory and practice of 3D graphics. The book's web site has many useful programs and code samples.""-Karen Rafferty, Queen's University, Belfast""The topics covered by this book are backed by the OpenFX modeling and animation software. This is a big plus in that it provides a practical perspective and encourages experimentation. … [This] will offer students a more interesting and hands-on learning experience, especially for those wishing to pursue a career in computer game development.""-Naganand Madhavapeddy, GameDeveloper>
Gao, Huai-Ling; Xu, Liang; Long, Fei; Pan, Zhao; Du, Yu-Xiang; Lu, Yang; Ge, Jin; Yu, Shu-Hong
2014-04-25
As macroscopic three dimensional (3D) architectures show increasing significance, much effort has been devoted to the hierarchical organization of 1D nanomaterials into serviceable macroscopic 3D assemblies. How to assemble 1D nanoscale building blocks into 3D hierarchical architectures is still a challenge. Herein we report a general strategy based on the use of ice as a template for assembling 1D nanostructures with high efficiency and good controllability. Free-standing macroscopic 3D Ag nanowire (AgNW) assemblies with hierarchical binary-network architectures are then fabricated from a 1D AgNW suspension for the first time. The microstructure of this 3D AgNW network endows it with electrical conductivity and allows it to be made into stretchable and foldable conductors with high electromechanical stability. These properties should make this kind of macroscopic 3D AgNW architecture and it composites suitable for electronic applications. PMID:24683064
Hierarchical approach to 'atomistic' 3-D MOSFET simulation
Asenov, A.; Brown, A. R.; J. H. Davies; S Saini
1999-01-01
We present a hierarchical approach to the 'atomistic' simulation of aggressively scaled sub-0.1-Î¼m MOSFETs. These devices are so small that their characteristics depend on the precise location of dopant atoms within them, not just on their average density. A full-scale three-dimensional drift-diffusion atomistic simulation approach is first described and used to verify more economical, but restricted, options. To reduce processor time and memory requirements at high drain voltage, we have de...
Transfer printing of 3D hierarchical gold structures using a sequentially imprinted polymer stamp
Complex three-dimensional (3D) hierarchical structures on polymeric materials are fabricated through a process referred to as sequential imprinting. In this work, the sequentially imprinted polystyrene film is used as a soft stamp to replicate hierarchical structures onto gold (Au) films, and the Au structures are then transferred to a substrate by transfer printing at an elevated temperature and pressure. Continuous and isolated 3D structures can be selectively fabricated with the assistance of thermo-mechanical deformation of the polymer stamp. Hierarchical Au structures are achieved without the need for a corresponding three-dimensionally patterned mold
Pose Estimation using a Hierarchical 3D Representation of Contours and Surfaces
Buch, Anders Glent; Kraft, Dirk; Kämäräinen, Joni-Kristian; Krüger, Norbert
We present a system for detecting the pose of rigid objects using texture and contour information. From a stereo image view of a scene, a sparse hierarchical scene representation is reconstructed using an early cognitive vision system. We define an object model in terms of a simple context descri...... variety of real-world objects rendered in a controlled virtual environment. Our experiments show the complementary role of 3D texture and contour information allowing for pose estimation with high robustness and accuracy....... descriptor of the contour and texture features to provide a sparse, yet descriptive object representation. Using our descriptors, we do a search in the correspondence space to perform outlier removal and compute the object pose. We perform an extensive evaluation of our approach with stereo images of a...
3D hierarchical architectures based on self-rolled-up silicon nitride membranes
This study presents the superior structural versatility of strained silicon nitride (SiNx) membranes as a platform for three-dimensional (3D) hierarchical tubular architectures. The effects of compressive and tensile stressed SiNx layer thickness on the self-rolled-up tube curvature, the sacrificial layer etching anisotropy on rolling direction and chirality, and stress engineering by localized thickness control or thermal treatment, are explored systematically. Using strained SiNx membranes as an electrically insulating and optically transparent mechanical support, compact 3D hierarchical architectures involving carbon nanotube arrays and passive electronic components are demonstrated by releasing the functional structures deposited and patterned in 2D. These examples highlight the uniqueness of this platform that exploits 2D processing and self-assembly to achieve highly functional 3D structures. (paper)
CASTLE3D - A Computer Aided System for Labelling Archaeological Excavations in 3D
Houshiar, H.; Borrmann, D.; Elseberg, J.; Nüchter, A.; Näth, F.; Winkler, S.
2015-08-01
Documentation of archaeological excavation sites with conventional methods and tools such as hand drawings, measuring tape and archaeological notes is time consuming. This process is prone to human errors and the quality of the documentation depends on the qualification of the archaeologist on site. Use of modern technology and methods in 3D surveying and 3D robotics facilitate and improve this process. Computer-aided systems and databases improve the documentation quality and increase the speed of data acquisition. 3D laser scanning is the state of the art in modelling archaeological excavation sites, historical sites and even entire cities or landscapes. Modern laser scanners are capable of data acquisition of up to 1 million points per second. This provides a very detailed 3D point cloud of the environment. 3D point clouds and 3D models of an excavation site provide a better representation of the environment for the archaeologist and for documentation. The point cloud can be used both for further studies on the excavation and for the presentation of results. This paper introduces a Computer aided system for labelling archaeological excavations in 3D (CASTLE3D). Consisting of a set of tools for recording and georeferencing the 3D data from an excavation site, CASTLE3D is a novel documentation approach in industrial archaeology. It provides a 2D and 3D visualisation of the data and an easy-to-use interface that enables the archaeologist to select regions of interest and to interact with the data in both representations. The 2D visualisation and a 3D orthogonal view of the data provide cuts of the environment that resemble the traditional hand drawings. The 3D perspective view gives a realistic view of the environment. CASTLE3D is designed as an easy-to-use on-site semantic mapping tool for archaeologists. Each project contains a predefined set of semantic information that can be used to label findings in the data. Multiple regions of interest can be joined under
3D CAD model retrieval method based on hierarchical multi-features
An, Ran; Wang, Qingwen
2015-12-01
The classical "Shape Distribution D2" algorithm takes the distance between two random points on a surface of CAD model as statistical features, and based on that it generates a feature vector to calculate the dissimilarity and achieve the retrieval goal. This algorithm has a simple principle, high computational efficiency and can get a better retrieval results for the simple shape models. Based on the analysis of D2 algorithm's shape distribution curve, this paper enhances the algorithm's descriptive ability for a model's overall shape through the statistics of the angle between two random points' normal vectors, especially for the distinctions between the model's plane features and curved surface features; meanwhile, introduce the ratio that a line between two random points cut off by the model's surface to enhance the algorithm's descriptive ability for a model's detailed features; finally, integrating the two shape describing methods with the original D2 algorithm, this paper proposes a new method based the hierarchical multi-features. Experimental results showed that this method has bigger improvements and could get a better retrieval results compared with the traditional 3D CAD model retrieval method.
Jong Uk Kim
2016-01-01
Full Text Available In nanoscience and nanotechnology, nanofabrication is critical. Among the required processes for nanofabrication, lithography is one of core issues. Although conventional photolithography with recent remarkable improvement has contributed to the industry during the past few decades, fabrication of 3-dimensional (3D nanostructure is still challenging. In this review, we summarize recent advances for the construction of 3D nanostructures by unconventional lithography and the combination of two top-down approaches or top-down and bottom-up approaches. We believe that the 3D hierarchical nanostructures described here will have a broad range of applications having adaptable levels of functional integration of precisely controlled nanoarchitectures that are required by not only academia, but also industry.
Benchmark for a 3D Monte Carlo boiling water reactor fluence computational package - MF3D
A detailed three dimensional model of a quadrant of an operating BWR has been developed using MCNP to calculate flux spectrum and fluence levels at various locations in the reactor system. The calculational package, MF3D, was benchmarked against test data obtained over a complete fuel cycle of the host BWR. The test package included activation wires sensitive in both the fast and thermal ranges. Comparisons between the calculational results and test data are good to within ten percent, making the MF3D package an accurate tool for neutron and gamma fluence computation in BWR pressure vessel internals. (orig.)
Design for scalability in 3D computer graphics architectures
Holten-Lund, Hans Erik
2002-01-01
This thesis describes useful methods and techniques for designing scalable hybrid parallel rendering architectures for 3D computer graphics. Various techniques for utilizing parallelism in a pipelines system are analyzed. During the Ph.D study a prototype 3D graphics architecture named Hybris has...... been developed. Hybris is a prototype rendering architeture which can be tailored to many specific 3D graphics applications and implemented in various ways. Parallel software implementations for both single and multi-processor Windows 2000 system have been demonstrated. Working hardware...... as a case study and an application of the Hybris graphics architecture....
In conformity with the protocol of the Workshop under Contract open-quotes Assessment of RBMK reactor safety using modern Western Codesclose quotes VNIIEF performed a neutronics computation series to compare western and VNIIEF codes and assess whether VNIIEF codes are suitable for RBMK type reactor safety assessment computation. The work was carried out in close collaboration with M.I. Rozhdestvensky and L.M. Podlazov, NIKIET employees. The effort involved: (1) cell computations with the WIMS, EKRAN codes (improved modification of the LOMA code) and the S-90 code (VNIIEF Monte Carlo). Cell, polycell, burnup computation; (2) 3D computation of static states with the KORAT-3D and NEU codes and comparison with results of computation with the NESTLE code (USA). The computations were performed in the geometry and using the neutron constants presented by the American party; (3) 3D computation of neutron kinetics with the KORAT-3D and NEU codes. These computations were performed in two formulations, both being developed in collaboration with NIKIET. Formulation of the first problem maximally possibly agrees with one of NESTLE problems and imitates gas bubble travel through a core. The second problem is a model of the RBMK as a whole with imitation of control and protection system controls (CPS) movement in a core
Practical rendering and computation with Direct3D 11
Zink, Jason; Hoxley, Jack
2011-01-01
Practical Rendering and Computation with Direct3D 11 packs in documentation and in-depth coverage of basic and high-level concepts related to using Direct 3D 11 and is a top pick for any serious programming collection. … perfect for a wide range of users. Any interested in computation and multicore models will find this packed with examples and technical applications.-Midwest Book Review, October 2011The authors have generously provided us with an optimal blend of concepts and philosophy, illustrative figures to clarify the more difficult points, and source code fragments to make the ideas con
Multitasking the code ARC3D. [for computational fluid dynamics
Barton, John T.; Hsiung, Christopher C.
1986-01-01
The CRAY multitasking system was developed in order to utilize all four processors and sharply reduce the wall clock run time. This paper describes the techniques used to modify the computational fluid dynamics code ARC3D for this run and analyzes the achieved speedup. The ARC3D code solves either the Euler or thin-layer N-S equations using an implicit approximate factorization scheme. Results indicate that multitask processing can be used to achieve wall clock speedup factors of over three times, depending on the nature of the program code being used. Multitasking appears to be particularly advantageous for large-memory problems running on multiple CPU computers.
3D Pharmacophore, hierarchical methods, and 5-HT4 receptor binding data.
Varin, Thibault; Saettel, Nicolas; Villain, Jonathan; Lesnard, Aurelien; Dauphin, François; Bureau, Ronan; Rault, Sylvain
2008-10-01
5-Hydroxytryptamine subtype-4 (5-HT(4)) receptors have stimulated considerable interest amongst scientists and clinicians owing to their importance in neurophysiology and potential as therapeutic targets. A comparative analysis of hierarchical methods applied to data from one thousand 5-HT(4) receptor-ligand binding interactions was carried out. The chemical structures were described as chemical and pharmacophore fingerprints. The definitions of indices, related to the quality of the hierarchies in being able to distinguish between active and inactive compounds, revealed two interesting hierarchies with the Unity (1 active cluster) and pharmacophore fingerprints (4 active clusters). The results of this study also showed the importance of correct choice of metrics as well as the effectiveness of a new alternative of the Ward clustering algorithm named Energy (Minimum E-Distance method). In parallel, the relationship between these classifications and a previously defined 3D 5-HT(4) antagonist pharmacophore was established. PMID:18821249
FUN3D and CFL3D Computations for the First High Lift Prediction Workshop
Park, Michael A.; Lee-Rausch, Elizabeth M.; Rumsey, Christopher L.
2011-01-01
Two Reynolds-averaged Navier-Stokes codes were used to compute flow over the NASA Trapezoidal Wing at high lift conditions for the 1st AIAA CFD High Lift Prediction Workshop, held in Chicago in June 2010. The unstructured-grid code FUN3D and the structured-grid code CFL3D were applied to several different grid systems. The effects of code, grid system, turbulence model, viscous term treatment, and brackets were studied. The SST model on this configuration predicted lower lift than the Spalart-Allmaras model at high angles of attack; the Spalart-Allmaras model agreed better with experiment. Neglecting viscous cross-derivative terms caused poorer prediction in the wing tip vortex region. Output-based grid adaptation was applied to the unstructured-grid solutions. The adapted grids better resolved wake structures and reduced flap flow separation, which was also observed in uniform grid refinement studies. Limitations of the adaptation method as well as areas for future improvement were identified.
The 3D-SEEP computer code user's manual
This report describes the 3D-SEEP computer code and presents the direction to use the code effectively. 3D-SEEP calculates the saturated-unsaturated time dependent or steady state flow of groundwater in permeable geologic media for the safety evaluation of nuclear waste disposal. 3D-SEEP is based on the 3-dimensional Galerkin finite element method. This allows the modeling of complex geometrical shapes and complicated patterns of geologic media. The flow is modeled by single phase flow governed by Darcy's law, and the simplified double porosity model is introduced to consider fractured media. This code can handle non-uniform flow regions having irregular boundaries and arbitrary degree of local anisotropy. (author)
Advanced computational tools for 3-D seismic analysis
Barhen, J.; Glover, C.W.; Protopopescu, V.A. [Oak Ridge National Lab., TN (United States)] [and others
1996-06-01
The global objective of this effort is to develop advanced computational tools for 3-D seismic analysis, and test the products using a model dataset developed under the joint aegis of the United States` Society of Exploration Geophysicists (SEG) and the European Association of Exploration Geophysicists (EAEG). The goal is to enhance the value to the oil industry of the SEG/EAEG modeling project, carried out with US Department of Energy (DOE) funding in FY` 93-95. The primary objective of the ORNL Center for Engineering Systems Advanced Research (CESAR) is to spearhead the computational innovations techniques that would enable a revolutionary advance in 3-D seismic analysis. The CESAR effort is carried out in collaboration with world-class domain experts from leading universities, and in close coordination with other national laboratories and oil industry partners.
3D computer visualization and animation of CANDU reactor core
Three-dimensional (3D) computer visualization and animation models of typical CANDU reactor cores (Darlington, Point Lepreau) have been developed using world-wide-web (WWW) browser based tools: JavaScript, hyper-text-markup language (HTML) and virtual reality modeling language (VRML). The 3D models provide three-dimensional views of internal control and monitoring structures in the reactor core, such as fuel channels, flux detectors, liquid zone controllers, zone boundaries, shutoff rods, poison injection tubes, ion chambers. Animations have been developed based on real in-core flux detector responses and rod position data from reactor shutdown. The animations show flux changing inside the reactor core with the drop of shutoff rods and/or the injection of liquid poison. The 3D models also provide hypertext links to documents giving specifications and historical data for particular components. Data in HTML format (or other format such as PDF, etc.) can be shown in text, tables, plots, drawings, etc., and further links to other sources of data can also be embedded. This paper summarizes the use of these WWW browser based tools, and describes the resulting 3D reactor core static and dynamic models. Potential applications of the models are discussed. (author)
Ball-scale based hierarchical multi-object recognition in 3D medical images
Bağci, Ulas; Udupa, Jayaram K.; Chen, Xinjian
2010-03-01
This paper investigates, using prior shape models and the concept of ball scale (b-scale), ways of automatically recognizing objects in 3D images without performing elaborate searches or optimization. That is, the goal is to place the model in a single shot close to the right pose (position, orientation, and scale) in a given image so that the model boundaries fall in the close vicinity of object boundaries in the image. This is achieved via the following set of key ideas: (a) A semi-automatic way of constructing a multi-object shape model assembly. (b) A novel strategy of encoding, via b-scale, the pose relationship between objects in the training images and their intensity patterns captured in b-scale images. (c) A hierarchical mechanism of positioning the model, in a one-shot way, in a given image from a knowledge of the learnt pose relationship and the b-scale image of the given image to be segmented. The evaluation results on a set of 20 routine clinical abdominal female and male CT data sets indicate the following: (1) Incorporating a large number of objects improves the recognition accuracy dramatically. (2) The recognition algorithm can be thought as a hierarchical framework such that quick replacement of the model assembly is defined as coarse recognition and delineation itself is known as finest recognition. (3) Scale yields useful information about the relationship between the model assembly and any given image such that the recognition results in a placement of the model close to the actual pose without doing any elaborate searches or optimization. (4) Effective object recognition can make delineation most accurate.
Ball-Scale Based Hierarchical Multi-Object Recognition in 3D Medical Images
Bagci, Ulas; Chen, Xinjian
2010-01-01
This paper investigates, using prior shape models and the concept of ball scale (b-scale), ways of automatically recognizing objects in 3D images without performing elaborate searches or optimization. That is, the goal is to place the model in a single shot close to the right pose (position, orientation, and scale) in a given image so that the model boundaries fall in the close vicinity of object boundaries in the image. This is achieved via the following set of key ideas: (a) A semi-automatic way of constructing a multi-object shape model assembly. (b) A novel strategy of encoding, via b-scale, the pose relationship between objects in the training images and their intensity patterns captured in b-scale images. (c) A hierarchical mechanism of positioning the model, in a one-shot way, in a given image from a knowledge of the learnt pose relationship and the b-scale image of the given image to be segmented. The evaluation results on a set of 20 routine clinical abdominal female and male CT data sets indicate th...
Real-time rendering of very large 3D scenes using hierarchical mesh simplification
Jönsson, Daniel
2009-01-01
Captured and generated 3D data can be so large that it creates a problem for today's computers since they do not fit into the main or graphics card memory. Therefore methods for handling and rendering the data must be developed. This thesis presents a way to pre-process and render out-of-core height map data for real time use. The pre-processing uses a mesh decimation API called Simplygon developed by Donya Labs to optimize the geometry. From the height map a normal map can also be created an...
Computing Radiative Transfer in a 3D Medium
Von Allmen, Paul; Lee, Seungwon
2012-01-01
A package of software computes the time-dependent propagation of a narrow laser beam in an arbitrary three- dimensional (3D) medium with absorption and scattering, using the transient-discrete-ordinates method and a direct integration method. Unlike prior software that utilizes a Monte Carlo method, this software enables simulation at very small signal-to-noise ratios. The ability to simulate propagation of a narrow laser beam in a 3D medium is an improvement over other discrete-ordinate software. Unlike other direct-integration software, this software is not limited to simulation of propagation of thermal radiation with broad angular spread in three dimensions or of a laser pulse with narrow angular spread in two dimensions. Uses for this software include (1) computing scattering of a pulsed laser beam on a material having given elastic scattering and absorption profiles, and (2) evaluating concepts for laser-based instruments for sensing oceanic turbulence and related measurements of oceanic mixed-layer depths. With suitable augmentation, this software could be used to compute radiative transfer in ultrasound imaging in biological tissues, radiative transfer in the upper Earth crust for oil exploration, and propagation of laser pulses in telecommunication applications.
Hu, Pei; Hou, Dongfang; Wen, Yanwei; Shan, Bin; Chen, Chaoji; Huang, Yunhui; Hu, Xianluo
2015-01-01
Novel three-dimensional (3D) hierarchical Nb3O7(OH) nanostructures with a sheaf-like nanoarchitecture were fabricated for the first time by a hydrothermal process. Interestingly, the nanosheafs are composed of nanorods with an average diameter of about 25 nm. The as-prepared 3D hierarchical nanostructures possess a high surface area of 77 m2 g-1 with pore diameters of ca. 4.2-12.5 nm. A possible growth mechanism based on the combined Ostwald ripening and self-assembly process was proposed. It is found that both the valence-band top and the conduction-band bottom consist of O 2p and Nb 4d orbitals. Importantly, the 3D hierarchical Nb3O7(OH) nanostructures exhibit enhanced photocatalytic activity for the degradation of Rhodamine B (RhB) under UV-visible light, which is attributed to the unusual hierarchical structure, high surface area, and hybridization of energy bands.Novel three-dimensional (3D) hierarchical Nb3O7(OH) nanostructures with a sheaf-like nanoarchitecture were fabricated for the first time by a hydrothermal process. Interestingly, the nanosheafs are composed of nanorods with an average diameter of about 25 nm. The as-prepared 3D hierarchical nanostructures possess a high surface area of 77 m2 g-1 with pore diameters of ca. 4.2-12.5 nm. A possible growth mechanism based on the combined Ostwald ripening and self-assembly process was proposed. It is found that both the valence-band top and the conduction-band bottom consist of O 2p and Nb 4d orbitals. Importantly, the 3D hierarchical Nb3O7(OH) nanostructures exhibit enhanced photocatalytic activity for the degradation of Rhodamine B (RhB) under UV-visible light, which is attributed to the unusual hierarchical structure, high surface area, and hybridization of energy bands. Electronic supplementary information (ESI) available: XRD patterns, XPS spectra, and SEM images. See DOI: 10.1039/c4nr06580h
3D artefact for concurrent scale calibration in Computed Tomography
Stolfi, Alessandro; De Chiffre, Leonardo
2016-01-01
A novel artefact for calibration of the scale in 3D X-ray Computed Tomography (CT) is presented. The artefact comprises a carbon fibre tubular structure on which a number of reference ruby spheres are glued. The artefact is positioned and scanned together with the workpiece inside the CT scanner...... providing a reference system for measurement. The artefact allows a considerable reduction of time by compressing the full process of calibration, scanning, measurement, and re-calibration, into a single process. The method allows a considerable reduction of the amount of data generated from CT scanning. A...
3D ultrasound computer tomography: update from a clinical study
Hopp, T.; Zapf, M.; Kretzek, E.; Henrich, J.; Tukalo, A.; Gemmeke, H.; Kaiser, C.; Knaudt, J.; Ruiter, N. V.
2016-04-01
Ultrasound Computer Tomography (USCT) is a promising new imaging method for breast cancer diagnosis. We developed a 3D USCT system and tested it in a pilot study with encouraging results: 3D USCT was able to depict two carcinomas, which were present in contrast enhanced MRI volumes serving as ground truth. To overcome severe differences in the breast shape, an image registration was applied. We analyzed the correlation between average sound speed in the breast and the breast density estimated from segmented MRIs and found a positive correlation with R=0.70. Based on the results of the pilot study we now carry out a successive clinical study with 200 patients. For this we integrated our reconstruction methods and image post-processing into a comprehensive workflow. It includes a dedicated DICOM viewer for interactive assessment of fused USCT images. A new preview mode now allows intuitive and faster patient positioning. We updated the USCT system to decrease the data acquisition time by approximately factor two and to increase the penetration depth of the breast into the USCT aperture by 1 cm. Furthermore the compute-intensive reflectivity reconstruction was considerably accelerated, now allowing a sub-millimeter volume reconstruction in approximately 16 minutes. The updates made it possible to successfully image first patients in our ongoing clinical study.
3D computer model of the VINCY cyclotron magnet
The VINCY Cyclotron magnetic field simulation was performed with the help of the three-dimensional (3D) software. The following aspects of the system were considered: 3D calculation of the magnetic field in the median plane, 3D calculation of the magnetic field in the extraction region, 3D calculation of the stray magnetic field. 8 refs., 17 figs., 3 tabs
Computation of 3D form factors in complex environments
The calculation of radiant interchange among opaque surfaces in a complex environment poses the general problem of determining the visible and hidden parts of the environment. In many thermal engineering applications, surfaces are separated by radiatively non-participating media and may be idealized as diffuse emitters and reflectors. Consenquently the net radiant energy fluxes are intimately related to purely geometrical quantities called form factors, that take into account hidden parts: the problem is reduced to the form factor evaluation. This paper presents the method developed for the computation of 3D form factors in the finite-element module of the system TRIO, which is a general computer code for thermal and fluid flow analysis. The method is derived from an algorithm devised for synthetic image generation. A comparison is performed with the standard contour integration method also implemented and suited to convex geometries. Several illustrative examples of finite-element thermal calculations in radiating enclosures are given
Computational Modelling of Piston Ring Dynamics in 3D
Dlugoš Jozef
2014-12-01
Full Text Available Advanced computational models of a piston assembly based on the level of virtual prototypes require a detailed description of piston ring behaviour. Considering these requirements, the piston rings operate in regimes that cannot, in general, be simplified into an axisymmetric model. The piston and the cylinder liner do not have a perfect round shape, mainly due to machining tolerances and external thermo-mechanical loads. If the ring cannot follow the liner deformations, a local loss of contact occurs resulting in blow-by and increased consumption of lubricant oil in the engine. Current computational models are unable to implement such effects. The paper focuses on the development of a flexible 3D piston ring model based on the Timoshenko beam theory using the multibody system (MBS. The MBS model is compared to the finite element method (FEM solution.
Effect of 3d computed microtomography resolution on reservoir rocks
The objective of this study is to evaluate the quantification process of geometric parameters when different computed microtomography spatial resolutions are employed. To this end, one reservoir rock sample was scanned with a 3D high energy computed microtomography system. The results show a strong difference in the acquisition, reconstruction and image processes, but do not present a significant loss of information on the microstructural parameters in the higher resolutions. However, it has been significantly loss of information in the lower resolution. - Highlights: ► The potential of one reservoir can be know when porosity parameter is calculated. ► MicroCT was used in order to estimate volume and porosity of one carbonate rock. ► It was evaluated how the parameters are affected when different spatial resolutions are employed. ► We do not have a significant loss of information on when high resolution is applied
Weixuan Jing
2014-01-01
Full Text Available With ZnO nanorods hydrothermally synthesized on manually assembled arrays of optical fiber cores, 3D arrays of ZnO nanorod-based cylindrically hierarchical structures with nominal pitch 250 μm or 375 μm were constructed. Based on micrographs of scanning electron microscopy and image processing operators of MATLAB software, the 3D arrays of cylindrically hierarchical structures were quantitatively characterized. The values of the actual diameters, the actual pitches, and the parallelism errors suggest that the process capability of the manual assembling is sufficient and the quality of the 3D arrays of cylindrically hierarchical structures is acceptable. The values of the characteristic parameters such as roughness, skewness, kurtosis, correlation length, and power spectrum density show that the surface morphologies of the cylindrically hierarchical structures not only were affected significantly by Zn2+ concentration of the growth solution but also were anisotropic due to different curvature radii of the optical fiber core at side and front view.
Burgess, Ian B; Loncar, Marko
2012-01-01
Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top-down lithography allows for designer patterning of arbitrary shapes, but is largely restricted to planar 2D structures. Self-assembly techniques facilitate easy fabrication of 3D photonic crystals, but controllable defect-integration is difficult. In this paper we combine the advantages of top-down and bottom-up fabrication, developing two techniques to deposit 2D-lithographically-patterned planar layers on top of or in between inverse-opal 3D photonic crystals and creating hierarchical structures that resemble the architecture of the bright green wing scales of the butterfly, Parides sesostris. These fabrication procedures, combining advantages of both top-down and bottom-up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D-2D photonic crystal devices.
Glasses for 3D ultrasound computer tomography: phase compensation
Zapf, M.; Hopp, T.; Ruiter, N. V.
2016-03-01
Ultrasound Computer Tomography (USCT), developed at KIT, is a promising new imaging system for breast cancer diagnosis, and was successfully tested in a pilot study. The 3D USCT II prototype consists of several hundreds of ultrasound (US) transducers on a semi-ellipsoidal aperture. Spherical waves are sequentially emitted by individual transducers and received in parallel by many transducers. Reflectivity volumes are reconstructed by synthetic aperture focusing (SAFT). However, straight forward SAFT imaging leads to blurred images due to system imperfections. We present an extension of a previously proposed approach to enhance the images. This approach includes additional a priori information and system characteristics. Now spatial phase compensation was included. The approach was evaluated with a simulation and clinical data sets. An increase in the image quality was observed and quantitatively measured by SNR and other metrics.
Self-assembled Synthesis of 3D CuO Flocculus-like Nanosheet-based Hierarchical Nanostructures
YIN Yong-kui; XU Yan-Li; LI Ying; REN Feng-yun; LI Shuang-jing; JIN Ge; LI Miao-jing
2013-01-01
A simple,surfactant-free,and environmentally benign method has been developed to synthesize a novel 3D flocculus-like CuO hierarchical nanostructure self-assembled with 2D nanosheet as building blocks.Detailed proofs demonstrate that the overall synthetic process underwent the dehydration and re-crystallization of precursor Cu(OH)2 nanowires,and the subsequent two-step oriented attachment.In addition,3D butterfly-like and flower-like CuO nanostructures consisted of 2D nanosheets could be obtained by adjusting the concentration of NaOH(cNaOH) in the solution.cNaOH played a key role in tailoring the thickness of the nanosheets and changing the morphology of the product.This report may be helpful to constructing fine-tune hierarchical CuO nanostructures under basic conditions.
CdS sensitized 3D hierarchical TiO2/ZnO heterostructure for efficient solar energy conversion.
Zheng, Zhaoke; Xie, Wen; Lim, Zhi Shiuh; You, Lu; Wang, Junling
2014-01-01
For conventional dye or quantum dot sensitized solar cells, which are fabricated using mesoporous films, the inefficient electron transport due to defects such as grain boundaries and surface traps is a major drawback. To simultaneously increase the carrier transport efficiency as well as the surface area, optimal-assembling of hierarchical nanostructures is an attractive approach. Here, a three dimensional (3D) hierarchical heterostructure, consisting of CdS sensitized one dimensional (1D) ZnO nanorods deposited on two dimensional (2D) TiO2 (001) nanosheet, is prepared via a solution-process method. Such heterstructure exhibits significantly enhanced photoelectric and photocatalytic H2 evolution performance compared with CdS sensitized 1D ZnO nanorods/1D TiO2 nanorods photoanode, as a result of the more efficient light harvesting over the entire visible light spectrum and the effective electron transport through a highly connected 3D network. PMID:25030846
CdS sensitized 3D hierarchical TiO2/ZnO heterostructure for efficient solar energy conversion
Zheng, Zhaoke; Xie, Wen; Lim, Zhi Shiuh; You, Lu; Wang, Junling
2014-01-01
For conventional dye or quantum dot sensitized solar cells, which are fabricated using mesoporous films, the inefficient electron transport due to defects such as grain boundaries and surface traps is a major drawback. To simultaneously increase the carrier transport efficiency as well as the surface area, optimal-assembling of hierarchical nanostructures is an attractive approach. Here, a three dimensional (3D) hierarchical heterostructure, consisting of CdS sensitized one dimensional (1D) ZnO nanorods deposited on two dimensional (2D) TiO2 (001) nanosheet, is prepared via a solution-process method. Such heterstructure exhibits significantly enhanced photoelectric and photocatalytic H2 evolution performance compared with CdS sensitized 1D ZnO nanorods/1D TiO2 nanorods photoanode, as a result of the more efficient light harvesting over the entire visible light spectrum and the effective electron transport through a highly connected 3D network. PMID:25030846
Computational and methodological developments towards 3D full waveform inversion
Etienne, V.; Virieux, J.; Hu, G.; Jia, Y.; Operto, S.
2010-12-01
Full waveform inversion (FWI) is one of the most promising techniques for seismic imaging. It relies on a formalism taking into account every piece of information contained in the seismic data as opposed to more classical techniques such as travel time tomography. As a result, FWI is a high resolution imaging process able to reach a spatial accuracy equal to half a wavelength. FWI is based on a local optimization scheme and therefore the main limitation concerns the starting model which has to be closed enough to the real one in order to converge to the global minimum. Another counterpart of FWI is the required computational resources when considering models and frequencies of interest. The task becomes even more tremendous when one tends to perform the inversion using the elastic equation instead of using the acoustic approximation. This is the reason why until recently most studies were limited to 2D cases. In the last few years, due to the increase of the available computational power, FWI has focused a lot of interests and continuous efforts towards inversion of 3D models, leading to remarkable applications up to the continental scale. We investigate the computational burden induced by FWI in 3D elastic media and propose some strategic features leading to the reduction of the numerical cost while providing a great flexibility in the inversion parametrization. First, in order to release the memory requirements, we developed our FWI algorithm in the frequency domain and take benefit of the wave-number redundancy in the seismic data to process a quite reduced number of frequencies. To do so, we extract frequency solutions from time marching techniques which are efficient for 3D structures. Moreover, this frequency approach permits a multi-resolution strategy by proceeding from low to high frequencies: the final model at one frequency is used as the starting model for the next frequency. This procedure overcomes partially the non-linear behavior of the inversion
3D Vectorial Time Domain Computational Integrated Photonics
Kallman, J S; Bond, T C; Koning, J M; Stowell, M L
2007-02-16
The design of integrated photonic structures poses considerable challenges. 3D-Time-Domain design tools are fundamental in enabling technologies such as all-optical logic, photonic bandgap sensors, THz imaging, and fast radiation diagnostics. Such technologies are essential to LLNL and WFO sponsors for a broad range of applications: encryption for communications and surveillance sensors (NSA, NAI and IDIV/PAT); high density optical interconnects for high-performance computing (ASCI); high-bandwidth instrumentation for NIF diagnostics; micro-sensor development for weapon miniaturization within the Stockpile Stewardship and DNT programs; and applications within HSO for CBNP detection devices. While there exist a number of photonics simulation tools on the market, they primarily model devices of interest to the communications industry. We saw the need to extend our previous software to match the Laboratory's unique emerging needs. These include modeling novel material effects (such as those of radiation induced carrier concentrations on refractive index) and device configurations (RadTracker bulk optics with radiation induced details, Optical Logic edge emitting lasers with lateral optical inputs). In addition we foresaw significant advantages to expanding our own internal simulation codes: parallel supercomputing could be incorporated from the start, and the simulation source code would be accessible for modification and extension. This work addressed Engineering's Simulation Technology Focus Area, specifically photonics. Problems addressed from the Engineering roadmap of the time included modeling the Auston switch (an important THz source/receiver), modeling Vertical Cavity Surface Emitting Lasers (VCSELs, which had been envisioned as part of fast radiation sensors), and multi-scale modeling of optical systems (for a variety of applications). We proposed to develop novel techniques to numerically solve the 3D multi-scale propagation problem for both the
Li, Guangci; Guan, Lili; Liu, Yunqi; Liu, Chenguang
2012-09-01
In the absence of template and surfactant, hierarchical nanostructured boehmite was synthesized via a simple solvothermal route using aluminum nitrate as aluminum source and isopropanol-toluene mixture as solvent. The crystal structures, morphologies and textural properties of products were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and N2 adsorption-desorption technique. The as-obtained hierarchical nanostructures consist of nanosheets keeping Brunauer-Emmett-Teller (BET) specific surface area and pore volume of ca. 264.7 m2/g and 1.2 cm3/g, respectively. The experimental results show that the longer reaction time and the lower reaction temperature are unfavorable to the formation of hierarchical nanostructures. Moreover, the properties of solvent have important influence on the morphology of product. The possible formation mechanism of boehmite hierarchical nanostructures was proposed and discussed.
Three-dimensional (3D) volumetric velocity measurement techniques, such as tomographic or holographic particle image velocimetry (PIV), rely upon the computationally intensive formation, storage and localized interrogation of multiple 3D particle intensity fields. Calculation of a single velocity field typically requires the extraction of particle intensities into tens of thousands of 3D sub-volumes or discrete particle clusters, the processing of which can significantly affect the performance of 3D cross-correlation based PIV and 3D particle tracking velocimetry (PTV). In this paper, a series of popular and customized volumetric data formats are presented and investigated using synthetic particle volumes and experimental data arising from tomographic PIV measurements of a turbulent boundary layer. Results show that the use of a sub-grid ordered non-zero intensity format with a sub-grid size of 16 × 16 × 16 points provides the best performance for cross-correlation based PIV analysis, while a particle clustered non-zero intensity format provides the best format for PTV applications. In practical tomographic PIV measurements the sub-grid ordered non-zero intensity format offered a 29% improvement in reconstruction times, while providing a 93% reduction in volume data requirements and a 28% overall improvement in cross-correlation based velocity analysis and validation times. (paper)
Atkinson, C.; Buchmann, N. A.; Soria, J.
2013-11-01
Three-dimensional (3D) volumetric velocity measurement techniques, such as tomographic or holographic particle image velocimetry (PIV), rely upon the computationally intensive formation, storage and localized interrogation of multiple 3D particle intensity fields. Calculation of a single velocity field typically requires the extraction of particle intensities into tens of thousands of 3D sub-volumes or discrete particle clusters, the processing of which can significantly affect the performance of 3D cross-correlation based PIV and 3D particle tracking velocimetry (PTV). In this paper, a series of popular and customized volumetric data formats are presented and investigated using synthetic particle volumes and experimental data arising from tomographic PIV measurements of a turbulent boundary layer. Results show that the use of a sub-grid ordered non-zero intensity format with a sub-grid size of 16 × 16 × 16 points provides the best performance for cross-correlation based PIV analysis, while a particle clustered non-zero intensity format provides the best format for PTV applications. In practical tomographic PIV measurements the sub-grid ordered non-zero intensity format offered a 29% improvement in reconstruction times, while providing a 93% reduction in volume data requirements and a 28% overall improvement in cross-correlation based velocity analysis and validation times.
Geometric approaches to computing 3D-landscape metrics
M.-S. Stupariu
2010-12-01
Full Text Available The relationships between patterns and processes lie at the core of modern landscape ecology. These dependences can be quantified by using indices related to the patch-corridor-matrix model. This model conceptualizes landscapes as planar mosaics consisting of discrete patches. On the other hand, relief variability is a key factor for many ecological processes, and therefore these processes can be better modeled by integrating information concerning the third dimension of landscapes. This can be done by generating a triangle mesh which approximates the original terrain. The aim of this methodological paper is to introduce two new constructions of triangulations which replace a digital elevation model. These approximation methods are compared with the method which was already used in the computation of 3D-landscape metrics (firstly for parameterized surfaces and secondly for two landscape mosaics. The statistical analysis shows that all three methods are of almost equal sensitivity in reflecting the relationship between terrain ruggedness and the patches areas and perimeters. In particular, either of the methods can be used for approximating the real values of these basic metrics. However, the two methods introduced in this paper have the advantage of yielding continuous approximations of the terrain, and this fact could be useful for further developments.
Computer Assisted Assessment within 3D Virtual Worlds
Ibáñez, María Blanca; Morillo, Diego; Santos, Patricia; Perez Calle, David; García Rueda, José Jesús; Hernández-Leo, Davinia; Delgado Kloos, Carlos
2011-01-01
3D Virtual Worlds are currently been explored as learning environments due to their capabilities to promote learner motivation. Most of the research has been focused on the deployment of learning strategies on them. However, a crucial component of the teaching-learning process: the assessment has been neglected. In this work, we present an architecture that integrates an engine QTI-compliant with a 3D virtual world platform. The rich set of interactions that can occur in a 3D virtual environm...
Interactive 3D computer model of the human corneolimbal region
Molvaer, Rikke Kongshaug; Andreasen, Arne; Heegaard, Steffen;
2013-01-01
plan. In all, one low-magnification and 24 high-magnification interactive 3D models were created. Immunohistochemistry against stem cell markers p63 and ΔNp63α was performed as a supplement to the 3D models. RESULTS: Using the interactive 3D models, we identified three types of stem cell niches......PURPOSE: This study aims to clarify the existence of and to map the localization of different proposed stem cell niches in the corneal limbal region. MATERIALS AND METHODS: One human eye was cut into 2200 consecutive sections. Every other section was stained with haematoxylin and eosin, digitized...... in the superior limbal region and one LEC, six LCs and 12 FSPs in the inferior limbal region. Only few LECs, LCs and FSPs were localized nasally and temporally. CONCLUSION: Interactive 3D models are a powerful tool that may help to shed more light on the existence and spatial localization of the different stem...
Kim, Geun Hyung; Son, Joon Gon
2009-03-01
The 3D bioplotter, which is one of the rapid-prototyping systems, enables us to produce the design-based scaffolds which could control good mechanical properties and pore structures for mimicking human organs. Although the plotting system has several advantages to fabricate a variety of designed scaffolds, the main disadvantage of scaffolds fabricated by the system is that the strand surfaces are too smooth and tend to discourage initial cell attachment within the scaffolds. To overcome the problem, we suggest a new 3D plotting method supplemented by piezoelectric vibration system for fabricating scaffolds that have hierarchical surface structures, which increase the surface roughness of the scaffold without any additional chemical process. The surface-modified 3D scaffold exhibited various positive qualities including enhanced compressive modulus and improved initial cell attachment and proliferation. Cell culturing results demonstrated that the interactions between chondrocytes and the scaffold were much more favorable than those between the cells and conventionally plotted 3D scaffolds. This process provides a feasible new technique for fabricating high-quality 3D scaffolds for tissue engineering applications.
COMPUTER AIDED DESIGN IN URBAN ARHITECTURE 3D MODELING
Nicolae Radu MARSANU; Silvia Mihaela RUSU
2010-01-01
The gap from the PC made sketches with the help of the china ink pen and ruler to the digitised drawing boards, high diagonal monitors and 3D projecting is truly spectacular. The increasingly efficient and more specialized programs allow the architects a whole range of facilities providing drawing commands and changes very easy to use, automatic rating, operating simultaneously in multiple windows, building sections and extracts of the plan, 3D views design and even projecting in virtual real...
Automatic Plant Annotation Using 3D Computer Vision
Nielsen, Michael
In this thesis 3D reconstruction was investigated for application in precision agriculture where previous work focused on low resolution index maps where each pixel represents an area in the field and the index represents an overall crop status in that area. 3D reconstructions of plants would all...... machinery or a field robot or a self guided tractor following a sample strategy based on overview maps of the field....
3D Printing device adaptable to Computer Numerical Control (CNC)
Gardan, Julien; DANESI, Frédéric; Roucoules, Lionel; Schneider, A
2014-01-01
This article presents the development of a 3D printing device for the additive manufacturing adapted to a CNC machining. The application involves the integration of a specific printing head. Additive manufacturing technology is most commonly used for modeling, prototyping, tooling through an exclusive machine or 3D printer. A global review and analysis of technologies show the additive manufacturing presents little independent solutions [6][9]. The problem studied especially the additive manu...
Computed 3D visualisation of an extinct cephalopod using computer tomographs
Lukeneder, Alexander
2012-01-01
The first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of t...
Hierarchical online appearance-based tracking for 3D head pose, eyebrows, lips, eyelids, and irises
Orozco, Javier; Rudovic, Ognjen; Gonzàlez, Jordi; Pantic, Maja
2013-01-01
In this paper, we propose an On-line Appearance-Based Tracker (OABT) for simultaneous tracking of 3D head pose, lips, eyebrows, eyelids and irises in monocular video sequences. In contrast to previously proposed tracking approaches, which deal with face and gaze tracking separately, our OABT can also be used for eyelid and iris tracking, as well as 3D head pose, lips and eyebrows facial actions tracking. Furthermore, our approach applies an on-line learning of changes in the appearance of the...
Hierarchical online appearance-based tracking for 3D head pose, eyebrows, lips, eyelids, and irises
Orozco, Javier; Rudovic, Ognjen; Gonzalez Garcia, Jordi; Pantic, Maja
2013-01-01
In this paper, we propose an On-line Appearance-Based Tracker (OABT) for simultaneous tracking of 3D head pose, lips, eyebrows, eyelids and irises in monocular video sequences. In contrast to previously proposed tracking approaches, which deal with face and gaze tracking separately, our OABT can als
3D segmentation of rodent brain structures using hierarchical shape priors and deformable models.
Zhang, Shaoting; Huang, Junzhou; Uzunbas, Mustafa; Shen, Tian; Delis, Foteini; Huang, Xiaolei; Volkow, Nora; Thanos, Panayotis; Metaxas, Dimitris N
2011-01-01
In this paper, we propose a method to segment multiple rodent brain structures simultaneously. This method combines deformable models and hierarchical shape priors within one framework. The deformation module employs both gradient and appearance information to generate image forces to deform the shape. The shape prior module uses Principal Component Analysis to hierarchically model the multiple structures at both global and local levels. At the global level, the statistics of relative positions among different structures are modeled. At the local level, the shape statistics within each structure is learned from training samples. Our segmentation method adaptively employs both priors to constrain the intermediate deformation result. This prior constraint improves the robustness of the model and benefits the segmentation accuracy. Another merit of our prior module is that the size of the training data can be small, because the shape prior module models each structure individually and combines them using global statistics. This scheme can preserve shape details better than directly applying PCA on all structures. We use this method to segment rodent brain structures, such as the cerebellum, the left and right striatum, and the left and right hippocampus. The experiments show that our method works effectively and this hierarchical prior improves the segmentation performance. PMID:22003750
From Digital to Physical: Computational Aspects of 3D Manufacturing
Baecher, Moritz Niklaus
2013-01-01
The desktop publishing revolution of the 1980s is currently repeating itself in 3D, referred to as desktop manufacturing. Online services such as Shapeways have become available, making personalized manufacturing on cutting edge additive manufacturing (AM) technologies accessible to a broad audience. Affordable desktop printers will soon take over, enabling people to fabricate
Software-based geometry operations for 3D computer graphics
Sima, M.; Iancu, D.; Glossner, J.; Schulte, M.; Mamidi, S.
2006-01-01
In order to support a broad dynamic range and a high degree of precision, many of 3D renderings fundamental algorithms have been traditionally performed in floating-point. However, fixed-point data representation is preferable over floatingpoint representation in graphics applications on embedded de
Computed 3D visualisation of an extinct cephalopod using computer tomographs.
Lukeneder, Alexander
2012-08-01
The first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of the genus Dissimilites. Object-based combined analyses from computed tomography and various computed 3D facility programmes help to understand morphological details as well as their ontogentical changes in fossil material. In this study, an additional goal was to show changes in locomotion during different ontogenetic phases of such fossil, marine shell-bearing animals (ammonoids). Hence, the presented models and tools can serve as starting points for discussions on morphology and locomotion of extinct cephalopods in general, and of the genus Dissimilites in particular. The heteromorph ammonoid genus Dissimilites is interpreted here as an active swimmer of the Tethyan Ocean. This study portrays non-destructive methods of 3D visualisation applied on palaeontological material, starting with computed tomography resulting in animated, high-quality video clips. The here presented 3D geometrical models and animation, which are based on palaeontological material, demonstrate the wide range of applications, analytical techniques and also outline possible limitations of 3D models in earth sciences and palaeontology. The realistic 3D models and motion pictures can easily be shared amongst palaeontologists. Data, images and short clips can be discussed online and, if necessary, adapted in morphological details and motion-style to better represent the cephalopod animal. PMID:24850976
Weight prediction of broiler chickens using 3D computer vision
Mortensen, Anders Krogh; Lisouski, Pavel; Ahrendt, Peter
2016-01-01
employed. The camera was robust to the changing light conditions of the broiler house as it contained its own infrared light source. A newly developed image processing algorithm is proposed. The algorithm first segmented the image with a range-based watershed algorithm, then extracted twelve different...... a platform weigher which may also include ill birds. In the current study, a fully-automatic 3D camera-based weighing system for broilers have been developed and evaluated in a commercial production environment. Specifically, a low-cost 3D camera (Kinect) that directly returned a depth image was...... period. A traditional platform weigher was used to estimate the reference weights. An average relative mean error of 7.8% between the predicted weights and the reference weights is achieved on a separate test set with 83 broilers in approximately 13,000 manually annotated images. The errors were...
Learning Projectile Motion with the Computer Game ``Scorched 3D``
Jurcevic, John S.
2008-01-01
For most of our students, video games are a normal part of their lives. We should take advantage of this medium to teach physics in a manner that is engrossing for our students. In particular, modern video games incorporate accurate physics in their game engines, and they allow us to visualize the physics through flashy and captivating graphics. I recently used the game "Scorched 3D" to help my students understand projectile motion.
The computational fluid dynamics code ANSYS CFX has been coupled with the neutron-kinetic core model DYN3D. ANSYS CFX calculates the fluid dynamics and related transport phenomena in the reactors coolant and provides the corresponding data to DYN3D. In the fluid flow simulation of the coolant, the core itself is modeled within the porous body approach. DYN3D calculates the neutron kinetics and the fuel behavior including the heat transfer to the coolant. The physical data interface between the codes is the volumetric heat release rate into the coolant. In the prototype that is currently available, the coupling is restricted to single-phase flow problems. In the time domain an explicit coupling of the codes has been implemented so far. Steady-state and transient verification calculations for two small-size test problems confirm the correctness of the implementation of the prototype coupling. The first test problem was a mini-core consisting of nine real-size fuel assemblies with quadratic cross section. Comparison was performed with the DYN3D stand-alone code. In the steady state, the effective multiplication factor obtained by the DYN3D/ANSYS CFX codes hows a deviation of 9.8 pcm from the DYN3D stand-alone solution. This difference can be attributed to the use of different water property packages in the two codes. The transient test case simulated the withdrawal of the control rod from the central fuel assembly at hot zero power in the same mini-core. Power increase during the introduction of positive reactivity and power reduction due to fuel temperature increase are calculated in the same manner by the coupled and the stand-alone codes. The maximum values reached during the power rise differ by about 1 MW at a power level of 50 MW. Beside the different water property packages, these differences are caused by the use of different flow solvers. The same calculations were carried for a mini-core with seven real-size fuel assemblies with hexagonal cross section in
Xu, Mengchi; Zhai, Dong; Xia, Lunguo; Li, Hong; Chen, Shiyi; Fang, Bing; Chang, Jiang; Wu, Chengtie
2016-07-01
The hierarchical structure of biomaterials plays an important role in the process of tissue reconstruction and regeneration. 3D-plotted scaffolds have been widely used for bone tissue engineering due to their controlled macropore structure and mechanical properties. However, the lack of micro- or nano-structures on the strut surface of 3D-plotted scaffolds, especially for bioceramic scaffolds, limits their biological activity. Inspired by the adhesive versatility of mussels and the active ion-chelating capacity of polydopamine, we set out to prepare a hierarchical bioceramic scaffold with controlled macropores and mussel-inspired surface nanolayers by combining the 3D-plotting technique with the polydopamine/apatite hybrid strategy in order to synergistically accelerate the osteogenesis and angiogenesis. β-Tricalcium phosphate (TCP) scaffolds were firstly 3D-plotted and then treated in dopamine-Tris/HCl and dopamine-SBF solutions to obtain TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds, respectively. It was found that polydopamine/apatite hybrid nanolayers were formed on the surface of both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds and TCP-DOPA-SBF scaffolds induced apatite mineralization for the second time during the cell culture. As compared to TCP scaffolds, both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds significantly promoted the osteogenesis of bone marrow stromal cells (BMSCs) as well as the angiogenesis of human umbilical vein endothelial cells (HUVECs), and the TCP-DOPA-SBF group presented the highest in vitro osteogenic/angiogenic activity among the three groups. Furthermore, both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds significantly improved the formation of new bone in vivo as compared to TCP scaffolds without a nanostructured surface. Our results suggest that the utilization of a mussel-inspired Ca, P-chelated polydopamine nanolayer on 3D-plotted bioceramic scaffolds is a viable and effective strategy to construct a hierarchical structure for synergistically
Xu, Mengchi; Zhai, Dong; Xia, Lunguo; Li, Hong; Chen, Shiyi; Fang, Bing; Chang, Jiang; Wu, Chengtie
2016-07-01
The hierarchical structure of biomaterials plays an important role in the process of tissue reconstruction and regeneration. 3D-plotted scaffolds have been widely used for bone tissue engineering due to their controlled macropore structure and mechanical properties. However, the lack of micro- or nano-structures on the strut surface of 3D-plotted scaffolds, especially for bioceramic scaffolds, limits their biological activity. Inspired by the adhesive versatility of mussels and the active ion-chelating capacity of polydopamine, we set out to prepare a hierarchical bioceramic scaffold with controlled macropores and mussel-inspired surface nanolayers by combining the 3D-plotting technique with the polydopamine/apatite hybrid strategy in order to synergistically accelerate the osteogenesis and angiogenesis. β-Tricalcium phosphate (TCP) scaffolds were firstly 3D-plotted and then treated in dopamine-Tris/HCl and dopamine-SBF solutions to obtain TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds, respectively. It was found that polydopamine/apatite hybrid nanolayers were formed on the surface of both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds and TCP-DOPA-SBF scaffolds induced apatite mineralization for the second time during the cell culture. As compared to TCP scaffolds, both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds significantly promoted the osteogenesis of bone marrow stromal cells (BMSCs) as well as the angiogenesis of human umbilical vein endothelial cells (HUVECs), and the TCP-DOPA-SBF group presented the highest in vitro osteogenic/angiogenic activity among the three groups. Furthermore, both TCP-DOPA-Tris and TCP-DOPA-SBF scaffolds significantly improved the formation of new bone in vivo as compared to TCP scaffolds without a nanostructured surface. Our results suggest that the utilization of a mussel-inspired Ca, P-chelated polydopamine nanolayer on 3D-plotted bioceramic scaffolds is a viable and effective strategy to construct a hierarchical structure for synergistically
Ball-Scale Based Hierarchical Multi-Object Recognition in 3D Medical Images
Bagci, Ulas; Udupa, Jayaram K.; Chen, Xinjian
2010-01-01
This paper investigates, using prior shape models and the concept of ball scale (b-scale), ways of automatically recognizing objects in 3D images without performing elaborate searches or optimization. That is, the goal is to place the model in a single shot close to the right pose (position, orientation, and scale) in a given image so that the model boundaries fall in the close vicinity of object boundaries in the image. This is achieved via the following set of key ideas: (a) A semi-automati...
Ren, Long; Hui, K N; Hui, K S; Liu, Yundan; Qi, Xiang; Zhong, Jianxin; Du, Yi; Yang, Jianping
2015-01-01
New and novel 3D hierarchical porous graphene aerogels (HPGA) with uniform and tunable meso-pores (e.g., 21 and 53 nm) on graphene nanosheets (GNS) were prepared by a hydrothermal self-assembly process and an in-situ carbothermal reaction. The size and distribution of the meso-pores on the individual GNS were uniform and could be tuned by controlling the sizes of the Co3O4 NPs used in the hydrothermal reaction. This unique architecture of HPGA prevents the stacking of GNS and promises more electrochemically active sites that enhance the electrochemical storage level significantly. HPGA, as a lithium-ion battery anode, exhibited superior electrochemical performance, including a high reversible specific capacity of 1100 mAh/g at a current density of 0.1 A/g, outstanding cycling stability and excellent rate performance. Even at a large current density of 20 A/g, the reversible capacity was retained at 300 mAh/g, which is larger than that of most porous carbon-based anodes reported, suggesting it to be a promising candidate for energy storage. The proposed 3D HPGA is expected to provide an important platform that can promote the development of 3D topological porous systems in a range of energy storage and generation fields. PMID:26382852
Dufaux A
2011-01-01
Full Text Available Technological solutions for obstacle-detection systems have been proposed to prevent accidents in safety-transport applications. In order to avoid the limits of these proposed technologies, an obstacle-detection system utilizing stereo cameras is proposed to detect and localize multiple objects at level crossings. Background subtraction is first performed using the color independent component analysis technique, which has proved its performance against other well-known object-detection methods. The main contribution is the development of a robust stereo-matching algorithm which reliably localizes in 3D each segmented object. A standard stereo dataset and real-world images are used to test and evaluate the performances of the proposed algorithm to prove the efficiency and the robustness of the proposed video-surveillance system.
Highlights: • 3D hierarchical flower-like Co3-xFexO4 ferrite were obtained using a facile two-step method. • The flower-like structure could provide facile electron transport paths in the electrode for fast Faradiac reaction. • The 3D hierarchical feature largely increases the amount of electroactive sites. • The 3D hierarchical Co3-xFexO4 ferrite exhibit excellent electrochemical performances with high capacitance, excellent rate capability and stability. - Abstract: A facile hydrothermal method combined with a post solution reaction is developed to synthesize interconnected three-dimension (3D) hierarchical Co3-xFexO4 ferrite (CF) on nickel foam. By controlling the experimental parameters, the structures of the products are tailored from nanoflowers to microflowers with different sized void interiors. The obtained 3D hierarchical flower-like CF are characterized by field emission scanning electron microscopy, X-ray diffraction, and inductively coupled plasma mass spectrometer analysis. The 3D hierarchical flower-like CF-nickel foam with the rational structural feature could be used as binder and conductive agent-free supercapacitor electrodes directly. Such integrated electrodes exhibit a high specific capacitance and well cycling stability when the charge-discharge current density is high. Remarkably, the 3D hierarchical CF microflowers exhibit specific capacitance values of 768 F g−1 at a constant current density of 6 A g−1. The CF microflowers also show high charge-discharge reversibility with an efficiency of 79.2% after 5000 cycles
Simulation on 3D acoustic fields on a concurrent computer
1996-01-01
In this paper. we present a method used to calculate the acoustic field created by a transducer. A parallel computer network was used to elaborate the effectiveness of the direct calculation of the Rayleigh Integral.
Ma, Fangwei; Ma, Di; Wu, Guang; Geng, Weidan; Shao, Jinqiu; Song, Shijiao; Wan, Jiafeng; Qiu, Jieshan
2016-05-10
A smart and sustainable strategy based on charge-induced self-assembly and nanocrystal-assisted catalytic graphitization is explored for the efficient construction of 3D nanostructure hierarchical porous graphitic carbons from the pectin biopolymer. The electrostatic interaction between the negatively charged pectin chains and magnesium ions plays a crucial role in the formation of 3D architectures. The 3D HPGCs possess a three-dimensional carbon framework with a hierarchical porous structure, flake-like graphitic carbon walls and high surface area (1320 m(2) g(-1)). The 3D HPGCs show an outstanding specific capacitance of 274 F g(-1) and excellent rate capability with a high capacitance retention of 85% at a high current density of 50 A g(-1) for supercapacitor electrodes. This strategy provided a novel approach to effectively construct 3D porous carbon nanostructures from biopolymers. PMID:27115341
The 3d International Workshop on Computational Electronics
Goodnick, Stephen M.
1994-09-01
The Third International Workshop on Computational Electronics (IWCE) was held at the Benson Hotel in downtown Portland, Oregon, on May 18, 19, and 20, 1994. The workshop was devoted to a broad range of topics in computational electronics related to the simulation of electronic transport in semiconductors and semiconductor devices, particularly those which use large computational resources. The workshop was supported by the National Science Foundation (NSF), the Office of Naval Research and the Army Research Office, as well as local support from the Oregon Joint Graduate Schools of Engineering and the Oregon Center for Advanced Technology Education. There were over 100 participants in the Portland workshop, of which more than one quarter represented research groups outside of the United States from Austria, Canada, France, Germany, Italy, Japan, Switzerland, and the United Kingdom. There were a total 81 papers presented at the workshop, 9 invited talks, 26 oral presentations and 46 poster presentations. The emphasis of the contributions reflected the interdisciplinary nature of computational electronics with researchers from the Chemistry, Computer Science, Mathematics, Engineering, and Physics communities participating in the workshop.
Computational 3-D Model of the Human Respiratory System
We are developing a comprehensive, morphologically-realistic computational model of the human respiratory system that can be used to study the inhalation, deposition, and clearance of contaminants, while being adaptable for age, race, gender, and health/disease status. The model ...
We facilely fabricate hierarchical 3D microspheres consisting of 2D V2O5 (vanadium pentoxide) nanosheets by a low temperature hydrothermal method and use it to structure hierarchical 3D micro-/nano-LIBs (lithium ion batteries) cathode. This is a template-free and facile method easy for scale-up production of hierarchical 3D micro-/nano-structured V2O5 spheres beneficial for high performance LIBs applications. Such a facile method resulted hierarchical 3D micro-/nano-V2O5 possess many unique features good for LIBs: (1) 2D V2O5 nanosheets facilitate the Li+ diffusions and electron transports; (2) hierarchical 3D micro-/nano-cathode structure built up by V2O5 nanosheet spheres will lead to the close and sufficient contact between electrolytes and activate materials and at the same time will create buffer volume to accommodate the volume change during discharging/charging process; and (3) micro-scale V2O5 spheres are easy to result in high cell packing density beneficial for high power battery. As revealed by the experimental results, the micro-/nano-V2O5 electrode demonstrates high initial discharge and charge capacities with no irreversible loss, high rate capacities at different currents and long-lasting lifespan. The high-energy and high-power performances of the micro-/nano-V2O5 electrode is ascribed to the unique hierarchical micro-/nano-structure merits of V2O5 spheres as abovementioned. In view of the advantages of facile fabrication method and unique features of 3D micro-/nano-V2O5 spheres for high power and high energy LIB battery, it is of great significance to beneficially broaden the applications of high-energy and high-power LIBs with creating novel hierarchical micro-/nano-structured V2O5 cathode materials. - Highlights: • Hierarchical 3D micro-/nano-V2O5 spheres were facile fabricated by a template free hydrothermal method for LIBs cathode. • High energy and high power LIBs were resulted from many unique features. • Unique hierarchical 3D micro
An Algorithm for Fast Computation of 3D Zernike Moments for Volumetric Images
Khalid M. Hosny; Hafez, Mohamed A.
2012-01-01
An algorithm was proposed for very fast and low-complexity computation of three-dimensional Zernike moments. The 3D Zernike moments were expressed in terms of exact 3D geometric moments where the later are computed exactly through the mathematical integration of the monomial terms over the digital image/object voxels. A new symmetry-based method was proposed to compute 3D Zernike moments with 87% reduction in the computational complexity. A fast 1D cascade algorithm was also employed to add m...
Computational 3D and reflectivity imaging with high photon efficiency
Shin, Dongeek; Kirmani, Ahmed; Shapiro, Jeffrey H.; Goyal, Vivek K
2014-01-01
Capturing depth and reflectivity images at low light levels from active illumination of a scene has wide-ranging applications. Conventionally, even with single-photon detectors, hundreds of photon detections are needed at each pixel to mitigate Poisson noise. We introduce a robust method for estimating depth and reflectivity using on the order of 1 detected photon per pixel averaged over the scene. Our computational imager combines physically accurate single-photon counting statistics with ex...
Zhong, Jiasong; Wang, Qingyao; Chen, Daqin; Chen, Leifeng; Yu, Hua; Lu, Hongwei; Ji, Zhenguo
2015-07-01
In this work, we developed a novel environmentally friendly strategy toward solvothermal synthesis of 3D hierarchical Cu2FeSnS4 microspheres with the utilization of L-cystine, an amino acid, as a coordination agent and sulfur donor. The crystal structure, surface morphology and microstructure of the as-prepared products were investigated. The results showed that the 3D hierarchical Cu2FeSnS4 microspheres were composed of stannite nanosheets, and the average thickness of nanosheets was 100 nm. Moreover, the 3D hierarchical Cu2FeSnS4 exhibited high efficiency in the photodegradation of RhB under visible light illumination, suggesting a promising candidate for treatment of organic pollutants in waste water.
3D neutron computed tomography. Requirements and applications
Other than X-rays, neutrons can penetrate most metals easily while delivering a high contrast for many light-weight elements. Especially their high sensitivity for hydrogen makes them a valuable tool for the detection of organic materials like lubricants, plastics or sealants within metal housings. Neutron radiography and tomography complement the application of X-ray for the inspection of complex and critical components like in automotive and aerospace applications. An overview about the technical and mathematical differences between neutron and X-ray tomography is given and the imperfections and limitations of a neutron setup are shown. Several examples of technical neutron computed tomography are given. (author)
Computation of Electrostatic Properties of 3D MEMS Structures
Majumdar, N
2006-01-01
Micro-Electro-Mechanical Systems (MEMS) normally have fixed or moving structures with cross-sections of the order of microns ($\\mu m$) and lengths of the order of tens or hundreds of microns. These structures are often plates or array of thin beams which, owing to their smallness, can be moved or deflected easily through the application of low voltages. Since electrostatic forces play a very major role in maneuvering these devices, a thorough understanding of the electrostatic properties of these structures is of critical importance, especially in the design phase of MEMS. In many cases, the electrostatic analysis of MEMS is carried out using boundary element method (BEM), while the structural analysis is carried out using finite element method (FEM). In this paper, we focus on accurate electrostatic analysis of MEMS using BEM. In particular, we consider the problem of computing the charge distribution and capacitance of thin conducting plates relevant to the numerical simulation of MEMS. The reason behind th...
MEI, G.
2015-05-01
Full Text Available In the calculating of convex hulls for point sets, a preprocessing procedure that is to filter the input points by discarding non-extreme points is commonly used to improve the computational efficiency. We previously proposed a quite straightforward preprocessing approach for accelerating 2D convex hull computation on the GPU. In this paper, we extend that algorithm to being used in 3D cases. The basic ideas behind these two preprocessing algorithms are similar: first, several groups of extreme points are found according to the original set of input points and several rotated versions of the input set; then, a convex polyhedron is created using the found extreme points; and finally those interior points locating inside the formed convex polyhedron are discarded. Experimental results show that: when employing the proposed preprocessing algorithm, it achieves the speedups of about 4x on average and 5x to 6x in the best cases over the cases where the proposed approach is not used. In addition, more than 95 percent of the input points can be discarded in most experimental tests.
3D Computational Simulation of Calcium Leaching in Cement Matrices
Gaitero, J. J.
2014-12-01
Full Text Available Calcium leaching is a degradation process consisting in progressive dissolution of the cement paste by migration of calcium atoms to the aggressive solution. It is therefore, a complex phenomenon involving several phases and dissolution and diffusion processes simultaneously. Along this work, a new computational scheme for the simulation of the degradation process in three dimensions was developed and tested. The toolkit was used to simulate accelerated calcium leaching by a 6M ammonium nitrate solution in cement matrices. The obtained outputs were the three dimensional representation of the matrix and the physicochemical properties of individual phases as a consequence of the degradation process. This not only makes it possible to study the evolution of such properties as a function of time but also as a function of the position within the matrix. The obtained results are in good agreement with experimental values of the elastic modulus in degraded and undegraded samples.El lixiviado de calcio es un proceso de degradación consistente en la disolución progresiva de la pasta de cemento por la migración de los átomos de calcio a la disolución agresiva. Se trata por tanto de un fenómeno complejo que involucra simultáneamente diferentes fases y procesos de disolución y difusión. En este trabajo se desarrolló y probó una nueva herramienta computacional para la simulación del proceso de degradación en tres dimensiones. Para ello se simuló el lixiviado de calcio acelerado provocado por una disolución de nitrato amónico 6M en matrices de cemento. Como resultado se obtuvieron la representación tridimensional de la matriz y las propiedades físico-químicas sus fases a lo largo del tiempo. Esto permitió estudiar la evolución de dichas propiedades a lo largo del proceso de degradación así como en función de su posición dentro de la matriz. Los resultados obtenidos coinciden con los valores experimentales del módulo elástico tanto
Hierarchical Poly Tree computer architectures defined by computational multidisciplinary mechanics
Padovan, Joe; Gute, Doug; Johnson, Keith
1989-01-01
This paper will develop an alternative computer architecture called the Poly Tree. Based on the requirements of computational mechanics and the concept of hierarchical substructuring, the paper will explore the development of problem-dependent parallel networks of processors which will enable significant, often superlinear, speed enhancements; provide a logical/efficient framework for linear/nonlinear and transient structural mechanics problems; and provide a logical framework from which to apply model reduction procedures. In addition, the paper will explore optimal processor arrangements which define the overall system granularity. Consideration will also be given to system I/O requirements.
Application of hierarchical computer complex concept for nuclear power plants
Development of hierarchical computer complex concept and its application to nuclear power plants is reported. The hierarchical computer complex is an integrated system for control, monitoring, and management of the plant and consists of a large number of computers and processors. The hierarchical computer complex (HCC) has three levels; The first and the uppermost level is for site management purposes, the second level is for unit level plant monitoring systems, and the third and the lowest level is that for local system control. Fast speed dataway linkage is provided between computers and/or controllers at each level and also between different levels for rapid transmission of control and information data
Wen, Xin; Luo, Wenjun; Guan, Zhongjie; Shao, Hansen; Fu, Gao; Zhou, Yong; Zou, Zhigang
2016-03-01
Cu2ZnSnS4 (CZTS) is one of the most promising light capture materials for solar cells or solar fuels. Construction of 3D hierarchical structure is very important for efficient optoelectronic devices. It is challenging to directly fabricate 3D hierarchical structure CZTS film by a facile solution method. Herein, we present a one-step sol-gel method for fabrication of CZTS thin films with 3D hierarchical structures. For the first time, it is found that the morphologies of thin films can be adjusted between dense, porous and 3D hierarchical structures by tuning anion ratios of Cl-/Ac- in precursor solution. Further analysis suggests the formation of intermediate phases of SnO2 nanoparticles and SnS2 nanosheets by tuning ratios of Cl-/Ac- in precursor solution, which has important effects on the formation of different nanostructures of CZTS. This study can deepen understanding of anion’ effect on morphologies of samples using a solution method and forms a reference to prepare novel nanostructures of other materials.
Effect of coordinate rotation on 3D molecular descriptors computed by DragonX
Hechinger, Manuel
2012-01-01
Quantitative structure-property relations (QSPR) employing descriptors derived from the 3D molecular structure are frequently applied for property prediction in various fields of research. In particular, DragonX is one of the most widely used software packages for descriptor calculation. The reliability of 3D molecular descriptors computed by DragonX has lately been investigated, thereby focusing on the effect of computational methods used for molecular structure optimization on the accuracy of the resulting molecular descriptors. The present contribution extends the analysis to a more intrinsic problem of DragonX descriptor evaluation resulting from the sensitivity of the computed 3D descriptors on the coordinate system used for molecule description. Evaluating several 3D descriptors for converged molecular structures rotated around all 3 spatial axes (affine coordinate transformations) yields systematically varying descriptor values. Since this unphysical behavior severely affects the descriptor reliability...
The accuracy of Single Photon Emission Computed Tomography (SPECT) images is degraded by physical effects, namely photon attenuation, Compton scatter and spatially varying collimator response. The 3D nature of these effects is usually neglected by the methods used to correct for these effects. To deal with the 3D nature of the problem, a 3D projector modeling the spread of photons in 3D can be used in iterative tomographic reconstruction. The 3D projector can be estimated analytically with some approximations, or using precise Monte Carlo simulations. This latter approach has not been applied to fully 3D reconstruction yet due to impractical storage and computation time. The goal of this paper was to determine the gain to be expected from fully 3D Monte Carlo (F3DMC) modeling of the projector in iterative reconstruction, compared to conventional 2D and 3D reconstruction methods. As a proof-of-concept, two small datasets were considered. The projections of the two phantoms were simulated using the Monte Carlo simulation code GATE, as well as the corresponding projector, by taking into account all physical effects (attenuation, scatter, camera point spread function) affecting the imaging process. F3DMC was implemented by using this 3D projector in a maximum likelihood expectation maximization (MLEM) iterative reconstruction. To assess the value of F3DMC, data were reconstructed using 4 methods: filtered backprojection (FBP), MLEM without attenuation correction (MLEM), MLEM with attenuation correction, Jaszczak scatter correction and 3D correction for depth-dependent spatial resolution using an analytical model (MLEMC) and F3DMC. Our results suggest that F3DMC improves mainly imaging sensitivity and signal-to-noise ratio (SNR): sensitivity is multiplied by about 103 and SNR is increased by 20 to 70% compared to MLEMC. Computation of a more robust projector and application of the method on more realistic datasets are currently under investigation. (authors)
Graphical abstract: Hierarchical porous carbon with 3D macroporous structure is prepared via a facile method and displays high lithium ion storage capacity and rate capability. - Highlights: • Hierarchical porous carbon is prepared from lignin via a facile method. • KOH acts both as activating agent and template in the preparation process. • Lignin based hierarchical porous carbon displays high lithium storage capacity. • Lignin based hierarchical porous carbon displays stable cycling stability. - Abstract: Hierarchical porous carbon derived from lignin (denoted as LHPC) was prepared via a facile method. In this method, KOH acts both as activating agent and template. The obtained LHPC was composed of unique 3D macroporous network with mesopores and micropores decorated on carbon walls. LHPC was further applied as the anode material of lithium ion battery and displayed a stable, high capacity of 470 mAh g−1 after 400 galvanostatic charge-discharge cycles at a current density of 200 mA g−1. Furthermore, LHPC displayed high cycling stability and perfect rate capability. This facile method for the preparation of LHPC offers a new route for the preparation of a series of hierarchical porous carbons for the application in supercapacitors, fuel cells, lithium ion batteries, etc
An Approach to Computer Modeling of Geological Faults in 3D and an Application
ZHU Liang-feng; HE Zheng; PAN Xin; WU Xin-cai
2006-01-01
3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geological faults in 3D is currently a topical research area. Structural modeling techniques of complex geological entities containing reverse faults are discussed and a series of approaches are proposed. The geological concepts involved in computer modeling and visualization of geological fault in 3D are explained, the type of data of geological faults based on geological exploration is analyzed, and a normative database format for geological faults is designed. Two kinds of modeling approaches for faults are compared: a modeling technique of faults based on stratum recovery and a modeling technique of faults based on interpolation in subareas. A novel approach, called the Unified Modeling Technique for stratum and fault, is presented to solve the puzzling problems of reverse faults, syn-sedimentary faults and faults terminated within geological models. A case study of a fault model of bed rock in the Beijing Olympic Green District is presented in order to show the practical result of this method. The principle and the process of computer modeling of geological faults in 3D are discussed and a series of applied technical proposals established. It strengthens our profound comprehension of geological phenomena and the modeling approach, and establishes the basic techniques of 3D geological modeling for practical applications in the field of geosciences.
Hu, Lianren; Ren, Yumei; Yang, Hongxia; Xu, Qun
2014-08-27
In this work, three-dimensional (3D) hierarchical MoS2/polyaniline (PANI) nanoflowers were successfully fabricated via a simple hydrothermal method. The crystal structure and morphology of the MoS2/PANI nanoflowers were characterized by SEM, TEM, XRD, XPS, and FT-IR spectra, revealing that the nanoflowers were composed of ultrathin nanoplates which consisted of few-layered MoS2 nanosheets with enlarged interlayer distance of the (002) plane and PANI. The excellent electrochemical performance of the 3D hierarchical MoS2/PANI nanoflowers was demonstrated. Further 3D hierarchical MoS2/C nanoflowers can be prepared conveniently by annealing the MoS2/PANI sample in a N2 atmosphere at 500 °C for 4 h. The obtained MoS2/C sample exhibited more excellent electrochemical performance due to its excellent electronic conductivity resulting from the close integration of MoS2 nanosheets with carbon matrix. High reversible capacity of 888.1 mAh g(-1) with the Coulombic efficiency maintained at above 90% from the first cycle were achieved at a current density of 100 mA g(-1). Even at a current density of 1000 mA g(-1), the reversible capacity of the MoS2/C sample could be retained at 511 mAh g(-1). The excellent electrochemical performance of these two samples could be attributed to the combined action of enlarged interlayer distance of the ultrathin MoS2 nanosheets, 3D architectures, hierarchical structures, and conductive material. Thus, these 3D hierarchical nanoflowers are competent as promising anode materials for high-performance lithium-ion batteries. PMID:25100439
Asenov, Asen; Brown, A. R.; Slavcheva, G.; Davies, J. H.
2000-01-01
When MOSFETs are scaled to deep submicron dimensions the discreteness and randomness of the dopant charges in the channel region introduces significant fluctuations in the device characteristics. This effect, predicted 20 year ago, has been confirmed experimentally and in simulation studies. The impact of the fluctuations on the functionality, yield, and reliability of the corresponding systems shifts the paradigm of the numerical device simulation. It becomes insufficient to simulate only one device representing one macroscopical design in a continuous charge approximation. An ensemble of macroscopically identical but microscopically different devices has to be characterized by simulation of statistically significant samples. The aims of the numerical simulations shift from predicting the characteristics of a single device with continuous doping towards estimating the mean values and the standard deviations of basic design parameters such as threshold voltage, subthreshold slope, transconductance, drive current, etc. for the whole ensemble of 'atomistically' different devices in the system. It has to be pointed out that even the mean values obtained from 'atomistic' simulations are not identical to the values obtained from continuous doping simulations. In this paper we present a hierarchical approach to the 'atomistic' simulation of aggressively scaled decanano MOSFETs. A full scale 3D drift-diffusion'atomostic' simulation approach is first described and used for verification of the more economical, but also more restricted, options. To reduce the processor time and memory requirements at high drain voltage we have developed a self-consistent option based on a thin slab solution of the current continuity equation only in the channel region. This is coupled to the Poisson's equation solution in the whole simulation domain in the Gummel iteration cycles. The accuracy of this approach is investigated in comparison with the full self-consistent solution. At low drain
A HIERARCHICAL SELF-HEALING SLA FOR CLOUD COMPUTING
Ahmad Mosallanejad; Rodziah Atan; Masrah Azmi Murad; Rusli Abdullah
2014-01-01
The service level agreement (SLA) is a mutual contract between the service provider and consumer which determines the agreed service level objective (SLO). The common SLA is a plain documental agreement without any relation to other dependent SLAs during the different layers of cloud computing. Hence, the cloud computing environment needs the hierarchical and autonomic SLA. This paper proposes the SH-SLA model to generate a hierarchical self-healing SLA in cloud computing. The self-healing ab...
3D SPIRAL COMPUTED TOMOGRAPHY FOR THE DIAGNOSIS OF AN ABDOMINAL TUMOUR
R.C. Tiutiuca; Iuliana Eva
2006-01-01
Patients with digestive illnesses requires a full exploration, cases where imagistic assets support (echographic examination, radiological data, computed tomography, magnetic resonance) are very usefully. Computed tomography, in this process, has a special value. The results from axial images are sustained by the informations supplied from three-dimensional reconstruction processes (3D reconstruction) with relevant importance in establishment of diagnosis and therapeutic plan.
3-D field computation: The near-triumph of commerical codes
Turner, L.R.
1995-07-01
In recent years, more and more of those who design and analyze magnets and other devices are using commercial codes rather than developing their own. This paper considers the commercial codes and the features available with them. Other recent trends with 3-D field computation include parallel computation and visualization methods such as virtual reality systems.
3D-SoftChip: A Novel Architecture for Next-Generation Adaptive Computing Systems
Lee Mike Myung-Ok
2006-01-01
Full Text Available This paper introduces a novel architecture for next-generation adaptive computing systems, which we term 3D-SoftChip. The 3D-SoftChip is a 3-dimensional (3D vertically integrated adaptive computing system combining state-of-the-art processing and 3D interconnection technology. It comprises the vertical integration of two chips (a configurable array processor and an intelligent configurable switch through an indium bump interconnection array (IBIA. The configurable array processor (CAP is an array of heterogeneous processing elements (PEs, while the intelligent configurable switch (ICS comprises a switch block, 32-bit dedicated RISC processor for control, on-chip program/data memory, data frame buffer, along with a direct memory access (DMA controller. This paper introduces the novel 3D-SoftChip architecture for real-time communication and multimedia signal processing as a next-generation computing system. The paper further describes the advanced HW/SW codesign and verification methodology, including high-level system modeling of the 3D-SoftChip using SystemC, being used to determine the optimum hardware specification in the early design stage.
3D COMPUTER SIMULATION FOR LIGNIFICATION OF ANCIENT CHINESE TIMBER BUILDINGS
无
2001-01-01
A pioneer research work was carried out by investigators engaged in surveying and mapping for describing ancient Chinese timber buildings by 3D frame graphs w ith a computer.Users can know the structural layers and the assembly process of the se buildings if the frame graphs are processed further with a computer model.Th is can be implemented by computer simulation technique.This technique display t he raw data on the screen of a computer and interactively manage them by combini ng technologies from computer graphics and image processing,multi-media technol ogy,artificial intelligence,highly parallel real-time computation technique an d human behavior science.This paper presents the implementing procedure of ligni fi cation simulation for large-sized wooden buildings as well as 3D dynamic assembl y of these buildings under the 3DS MAX environment.The results from computer sim ulation are also shown in the paper.
In order to improve quality of 3D X-ray tomography reconstruction for Non Destructive Testing (NDT), we investigate in this paper hierarchical Bayesian methods. In NDT, useful prior information on the volume like the limited number of materials or the presence of homogeneous area can be included in the iterative reconstruction algorithms. In hierarchical Bayesian methods, not only the volume is estimated thanks to the prior model of the volume but also the hyper parameters of this prior. This additional complexity in the reconstruction methods when applied to large volumes (from 5123 to 81923 voxels) results in an increasing computational cost. To reduce it, the hierarchical Bayesian methods investigated in this paper lead to an algorithm acceleration by Variational Bayesian Approximation (VBA) [1] and hardware acceleration thanks to projection and back-projection operators paralleled on many core processors like GPU [2]. In this paper, we will consider a Student-t prior on the gradient of the image implemented in a hierarchical way [3, 4, 1]. Operators H (forward or projection) and Ht (adjoint or back-projection) implanted in multi-GPU [2] have been used in this study. Different methods will be evalued on synthetic volume 'Shepp and Logan' in terms of quality and time of reconstruction. We used several simple regularizations of order 1 and order 2. Other prior models also exists [5]. Sometimes for a discrete image, we can do the segmentation and reconstruction at the same time, then the reconstruction can be done with less projections
3D Slicer as an image computing platform for the Quantitative Imaging Network.
Fedorov, Andriy; Beichel, Reinhard; Kalpathy-Cramer, Jayashree; Finet, Julien; Fillion-Robin, Jean-Christophe; Pujol, Sonia; Bauer, Christian; Jennings, Dominique; Fennessy, Fiona; Sonka, Milan; Buatti, John; Aylward, Stephen; Miller, James V; Pieper, Steve; Kikinis, Ron
2012-11-01
Quantitative analysis has tremendous but mostly unrealized potential in healthcare to support objective and accurate interpretation of the clinical imaging. In 2008, the National Cancer Institute began building the Quantitative Imaging Network (QIN) initiative with the goal of advancing quantitative imaging in the context of personalized therapy and evaluation of treatment response. Computerized analysis is an important component contributing to reproducibility and efficiency of the quantitative imaging techniques. The success of quantitative imaging is contingent on robust analysis methods and software tools to bring these methods from bench to bedside. 3D Slicer is a free open-source software application for medical image computing. As a clinical research tool, 3D Slicer is similar to a radiology workstation that supports versatile visualizations but also provides advanced functionality such as automated segmentation and registration for a variety of application domains. Unlike a typical radiology workstation, 3D Slicer is free and is not tied to specific hardware. As a programming platform, 3D Slicer facilitates translation and evaluation of the new quantitative methods by allowing the biomedical researcher to focus on the implementation of the algorithm and providing abstractions for the common tasks of data communication, visualization and user interface development. Compared to other tools that provide aspects of this functionality, 3D Slicer is fully open source and can be readily extended and redistributed. In addition, 3D Slicer is designed to facilitate the development of new functionality in the form of 3D Slicer extensions. In this paper, we present an overview of 3D Slicer as a platform for prototyping, development and evaluation of image analysis tools for clinical research applications. To illustrate the utility of the platform in the scope of QIN, we discuss several use cases of 3D Slicer by the existing QIN teams, and we elaborate on the future
Efficient computation of steady, 3D water-wave patterns, application to hovercraft-type flows
Lewis, M. R.; Koren, Barry
2002-01-01
Numerical methods for the computation of stationary free surfaces is the subject of much current research in computational engineering. The present report is directed towards free surfaces in maritime engineering. Of interest here are the long steady waves generated by hovercraft and ships, the gravity waves. In the present report an existing 2D iterative method for the computation of stationary gravity-wave solutions is extended to 3D, numerically investigated, and improved. The method emplo...
Creation of 3D digital computer model of radiation conditions about ChNPP
Information technology for creation of 3D digital computer model of radiation conditions (RC) around the ChNPP was developed on the basis of geo information technologies. 3D digital computer model of the RC was created, which is aimed at taking of decisions and situational modeling. Data analysis on the RC within the 30 km exclusion zone was carried out and the RC data base was created. Surface distribution and volumetric digital model of 137Cs on the area adjoining to the ChNPP industrial site were made
Development of 3-D Radiosurgery Planning System Using IBM Personal Computer
Recently, stereotactic radiosurgery plan is required with the information of 3-D image and dose distribution. A project has been doing if developing LINAC based stereotactic radiosurgery since April 1991. The purpose of this research is to develop 3-D radiosurgery planning system using personal computer. The procedure of this research is based on two steps. The first step is to develop 3-D localization system, which input the image information of the patient, coordinate transformation, the position and shape of target, and patient contour into computer system using CT image and stereotactic frame. The second step is to develop 3-D dose planning system, which compute dose distribution on image plane, display on high resolution monitor both isodose distribution and patient image simultaneously and develop menu-driven planning system. This prototype of radiosurgery planning system was applied recently for several clinical cases. It was shown that our planning system is fast, accurate and efficient while making it possible to handle various kinds of image modalities such as angiography, CT and MRI. It makes it possible to develop general 3-D planning system using beam eye view or CT simulation in radiation therapy in future
Ba, Ningning; Zhu, Lianjie; Li, Hongbin; Zhang, Guangzhi; Li, Jianfa; Sun, Jingfeng
2016-03-01
3-dimensional (3D) rod-like CuO with nanowire hierarchical structure has been synthesized successfully by a facile ultrasound assisted method combined with thermal conversion, using rouaite Cu2(OH)3NO3 as the precursor. The product was characterized by XRD, SEM, TEM, HRTEM and FT-IR spectrum. Its optical properties were studied by means of UV-Vis diffuse reflectance absorption spectroscopy and photoluminescence (PL) spectrum. Series of control experiments have been performed to explore influencing factors to the product morphologies and a possible formation mechanism has been proposed. The results show that each CuO rod assembled by tens of nanowires is 200-300 nm in diameter and about 1000 nm in length. Each nanowire contains many interconnected nanoparticles with sizes of about 15 nm. Particularly, ultrasound processing was found beneficial to the formation of the 3D rod-like CuO with nanowire hierarchical structure.
3-D Multiphase Segmentation of X-Ray Micro Computed Tomography Data of Geologic Materials
Tuller, M.; Kulkarni, R.; Fink, W.
2011-12-01
Advancements of noninvasive imaging methods such as X-Ray Computed Tomography (CT) led to a recent surge of applications in Geoscience. While substantial efforts and resources have been devoted to advance CT technology and micro-scale analysis, the development of a stable 3-D multiphase image segmentation method applicable to large datasets is lacking. To eliminate the need for wet/dry or dual energy scans, image alignment, and subtraction analysis, commonly applied in synchrotron X-Ray micro CT, a segmentation method based on a Bayesian Markov Random Field (MRF) framework amenable to true 3-D multiphase processing was developed and evaluated. Furthermore, several heuristic and deterministic combinatorial optimization schemes required to solve the labeling problem of the MRF image model were implemented and tested for computational efficiency and their impact on segmentation results. Test results for natural and artificial porous media datasets demonstrate great potential of the MRF image model for 3-D multiphase segmentation.
Computer-Assisted Hepatocellular Carcinoma Ablation Planning Based on 3-D Ultrasound Imaging.
Li, Kai; Su, Zhongzhen; Xu, Erjiao; Guan, Peishan; Li, Liu-Jun; Zheng, Rongqin
2016-08-01
To evaluate computer-assisted hepatocellular carcinoma (HCC) ablation planning based on 3-D ultrasound, 3-D ultrasound images of 60 HCC lesions from 58 patients were obtained and transferred to a research toolkit. Compared with virtual manual ablation planning (MAP), virtual computer-assisted ablation planning (CAP) consumed less time and needle insertion numbers and exhibited a higher rate of complete tumor coverage and lower rate of critical structure injury. In MAP, junior operators used less time, but had more critical structure injury than senior operators. For large lesions, CAP performed better than MAP. For lesions near critical structures, CAP resulted in better outcomes than MAP. Compared with MAP, CAP based on 3-D ultrasound imaging was more effective and achieved a higher rate of complete tumor coverage and a lower rate of critical structure injury; it is especially useful for junior operators and with large lesions, and lesions near critical structures. PMID:27126243
Liao Gui-Hong
2009-01-01
Full Text Available Abstract Three-dimensional (3D flower-like hierarchicalβ-Ni(OH2hollow architectures were synthesized by a facile hydrothermal route. The as-obtained products were well characterized by XRD, SEM, TEM (HRTEM, SAED, and DSC-TGA. It was shown that the 3D flower-like hierarchicalβ-Ni(OH2hollow architectures with a diameter of several micrometers are assembled from nanosheets with a thickness of 10–20 nm and a width of 0.5–2.5 μm. A rational mechanism of formation was proposed on the basis of a range of contrasting experiments. 3D flower-like hierarchical NiO hollow architectures with porous structure were obtained after thermal decomposition at appropriate temperatures. UV–Vis spectra reveal that the band gap of the as-synthesized NiO samples was about 3.57 eV, exhibiting obviously red shift compared with the bulk counterpart.
Analyzing 3D xylem networks in Vitis vinifera using High Resolution Computed Tomography (HRCT)
Recent developments in High Resolution Computed Tomography (HRCT) have made it possible to visualize three dimensional (3D) xylem networks without time consuming, labor intensive physical sectioning. Here we describe a new method to visualize complex vessel networks in plants and produce a quantitat...
Detection of screw threads in computed tomography 3D density fields
Kosarevsky, Sergey
2013-01-01
In this paper, a new method is proposed to automatically detect screw threads in 3D density fields obtained from computed tomography measurement devices. The described method can be used to automate many operations during screw thread inspection process and drastically reduce operator's influence on the measurement process resulting in lower measurement times and increased repeatability.
Simplified 3D model of a PWR reactor vessel using fluid dynamics code ANSYS CFX computational
This paper presents the results from the calculation of the steady state simulation with model of CFD (computational fluid dynamic) operating under conditions of operation at full power (Hot Full Power). Development and the CFD model results show the usefulness of these codes for calculating 3D of the variable thermohydraulics of these reactors.
The Effects of 3D Computer Simulation on Biology Students' Achievement and Memory Retention
Elangovan, Tavasuria; Ismail, Zurida
2014-01-01
A quasi experimental study was conducted for six weeks to determine the effectiveness of two different 3D computer simulation based teaching methods, that is, realistic simulation and non-realistic simulation on Form Four Biology students' achievement and memory retention in Perak, Malaysia. A sample of 136 Form Four Biology students in Perak,…
3D image fusion and guidance for computer-assisted bronchoscopy
Higgins, W. E.; Rai, L.; Merritt, S. A.; Lu, K.; Linger, N. T.; Yu, K. C.
2005-11-01
The standard procedure for diagnosing lung cancer involves two stages. First, the physician evaluates a high-resolution three-dimensional (3D) computed-tomography (CT) chest image to produce a procedure plan. Next, the physician performs bronchoscopy on the patient, which involves navigating the the bronchoscope through the airways to planned biopsy sites. Unfortunately, the physician has no link between the 3D CT image data and the live video stream provided during bronchoscopy. In addition, these data sources differ greatly in what they physically give, and no true 3D planning tools exist for planning and guiding procedures. This makes it difficult for the physician to translate a CT-based procedure plan to the video domain of the bronchoscope. Thus, the physician must essentially perform biopsy blindly, and the skill levels between different physicians differ greatly. We describe a system that enables direct 3D CT-based procedure planning and provides direct 3D guidance during bronchoscopy. 3D CT-based information on biopsy sites is provided interactively as the physician moves the bronchoscope. Moreover, graphical information through a live fusion of the 3D CT data and bronchoscopic video is provided during the procedure. This information is coupled with a series of computer-graphics tools to give the physician a greatly augmented reality of the patient's interior anatomy during a procedure. Through a series of controlled tests and studies with human lung-cancer patients, we have found that the system not only reduces the variation in skill level between different physicians, but also increases biopsy success rate.
Computer assisted determination of acetabular cup orientation using 2D-3D image registration
2D-3D image-based registration methods have been developed to measure acetabular cup orientation after total hip arthroplasty (THA). These methods require registration of both the prosthesis and the CT images to 2D radiographs and compute implant position with respect to a reference. The application of these methods is limited in clinical practice due to two limitations: (1) the requirement of a computer-aided design (CAD) model of the prosthesis, which may be unavailable due to the proprietary concerns of the manufacturer, and (2) the requirement of either multiple radiographs or radiograph-specific calibration, usually unavailable for retrospective studies. In this paper, we propose a new method to address these limitations. A new formulation for determination of post-operative cup orientation, which couples a radiographic measurement with 2D-3D image matching, was developed. In our formulation, the radiographic measurement can be obtained with known methods so that the challenge lies in the 2D-3D image matching. To solve this problem, a hybrid 2D-3D registration scheme combining a landmark-to-ray 2D-3D alignment with a robust intensity-based 2D-3D registration was used. The hybrid 2D-3D registration scheme allows computing both the post-operative cup orientation with respect to an anatomical reference and the pelvic tilt and rotation with respect to the X-ray imaging table/plate. The method was validated using 2D adult cadaver hips. Using the hybrid 2D-3D registration scheme, our method showed a mean accuracy of 1.0 ± 0.7 (range from 0.1 to 2.0 ) for inclination and 1.7 ± 1.2 (range from 0.0 to 3.9 ) for anteversion, taking the measurements from post-operative CT images as ground truths. Our new solution formulation and the hybrid 2D-3D registration scheme facilitate estimation of post-operative cup orientation and measurement of pelvic tilt and rotation. (orig.)
Computer assisted determination of acetabular cup orientation using 2D-3D image registration
Zheng, Guoyan; Zhang, Xuan [University of Bern, Institute for Surgical Technology and Biomechanics, Bern (Switzerland)
2010-09-15
2D-3D image-based registration methods have been developed to measure acetabular cup orientation after total hip arthroplasty (THA). These methods require registration of both the prosthesis and the CT images to 2D radiographs and compute implant position with respect to a reference. The application of these methods is limited in clinical practice due to two limitations: (1) the requirement of a computer-aided design (CAD) model of the prosthesis, which may be unavailable due to the proprietary concerns of the manufacturer, and (2) the requirement of either multiple radiographs or radiograph-specific calibration, usually unavailable for retrospective studies. In this paper, we propose a new method to address these limitations. A new formulation for determination of post-operative cup orientation, which couples a radiographic measurement with 2D-3D image matching, was developed. In our formulation, the radiographic measurement can be obtained with known methods so that the challenge lies in the 2D-3D image matching. To solve this problem, a hybrid 2D-3D registration scheme combining a landmark-to-ray 2D-3D alignment with a robust intensity-based 2D-3D registration was used. The hybrid 2D-3D registration scheme allows computing both the post-operative cup orientation with respect to an anatomical reference and the pelvic tilt and rotation with respect to the X-ray imaging table/plate. The method was validated using 2D adult cadaver hips. Using the hybrid 2D-3D registration scheme, our method showed a mean accuracy of 1.0 {+-} 0.7 (range from 0.1 to 2.0 ) for inclination and 1.7 {+-} 1.2 (range from 0.0 to 3.9 ) for anteversion, taking the measurements from post-operative CT images as ground truths. Our new solution formulation and the hybrid 2D-3D registration scheme facilitate estimation of post-operative cup orientation and measurement of pelvic tilt and rotation. (orig.)
Zhao, Lei; Sui, Xu-Lei; Li, Jia-Long; Zhang, Jing-Jia; Zhang, Li-Mei; Wang, Zhen-Bo
2016-06-29
Three-dimensional hierarchical nitrogen-doped graphene (3D-NG) frameworks were successfully fabricated through a feasible solution dip-coating method with commercially available sponges as the initial backbone. A spongy template can help hinder the graphene plates restacking in the period of the annealing process. The Pt/3D-NG catalyst was synthesized employing a polyol reduction process. The resultant Pt/3D-NG exhibits 2.3 times higher activity for methanol electro-oxidation along with the improvement in stability as compared with Pt/G owing to their favorable features including large specific surface area, high pore volume, high N doping level, and the homogeneous dispersion of Pt nanoparticles. Besides, Pt/3D-NG also presents high oxygen reduction reaction (ORR) performance in acid media when compared with Pt/3D-G and Pt/G. This work raises a valid solution for the fabrication of 3D functional freestanding graphene-based composites for a variety of applications in fuel cell catalysis, energy storage, and conversion. PMID:27266527
The computation of steady 3-D separated flows over aerodynamic bodies at incidence and yaw
Pulliam, T. H.; Pan, D.
1986-01-01
This paper describes the implementation of a general purpose 3-D NS code and its application to simulated 3-D separated vortical flows over aerodynamic bodies. The thin-layer Reynolds-averaged NS equations are solved by an implicit approximate factorization scheme. The pencil data structure enables the code to run on very fine grids using only limited incore memories. Solutions of a low subsonic flow over an inclined ellipsoid are compared with experimental data to validate the code. Transonic flows over a yawed elliptical wing at incidence are computed and separations occurred at different yaw angles are discussed.
Conventional bone histomorphometry is an important method for quantitative evaluation of bone microstructure. X-ray computed microtomography is a noninvasive technique, which can be used to evaluate histomorphometric indices in trabecular bones (BV/TV, BS/BV, Tb.N, Tb.Th, Tb.Sp). In this technique, the output 3D images are used to quantify the whole sample, differently from the conventional one, in which the quantification is performed in 2D slices and extrapolated for 3D case. In this work, histomorphometric quantification using synchrotron 3D X-ray computed microtomography was performed to quantify pathological samples of human bone. Samples of human bones were cut into small blocks (8 mm x 8 mm x 10 mm) with a precision saw and then imaged. The computed microtomographies were obtained at SYRMEP (Synchrotron Radiation for MEdical Physics) beamline, at ELETTRA synchrotron radiation facility (Italy). The obtained 3D images yielded excellent resolution and details of intra-trabecular bone structures, including marrow present inside trabeculae. Histomorphometric quantification was compared to literature as well. (author)
Bai, Hongwei; Liu, Lei; Liu, Zhaoyang; Sun, Darren Delai
2013-08-01
Hierarchical 3D dendritic TiO2 nanospheres building with ultralong 1D TiO2 nanoribbon/wires were hydrothermally synthesized via controlling the hydrolysis rate of precursor by EG. It is found that the EG and Cl(-) in the precursor solution are the dominant factors in controlling the hydrolysis rate of Ti(4+) from TTIP, and the growing direction of 1D TiO2, respectively. Through optimizing the molar ratio of TTIP:EG, hierarchical 3D dendritic TiO2 nanospheres building with long 1D nanoribbons (TiO2 nanoribbon spheres) were synthesized at a molar ratio of TTIP:EG = 1:2. And hierarchical 3D dendritic TiO2 nanospheres building with even longer and thinner 1D TiO2 nanowires (TiO2 nanowire spheres) were synthesized via further reducing the hydrolysis rate of Ti(4+) by increasing the content of EG at a molar ratio of TTIP:EG = 1:3. The hierarchical 3D dendritic TiO2 nanoribbon/wire spheres were well characterized by a variety of techniques such as FESEM, TEM, XRD, N2 adsorption/desorption, UV-vis spectra, etc. A "win-win" strategy was developed to integrate the hierarchical TiO2 nanoribbon/wire spheres and membrane for high performance photocatalytic membrane water purification through maximizing the advantages of TiO2 photocatalysis and membrane, while minimizing their disadvantages. Hierarchical TiO2 nanoribbon/wire spheres exhibited high performance for water purification in terms of high flux, low fouling, high removal rate of pollutants, and long lifespan of membrane, both in concurrent dead end and cross flow membrane system. The rationale behind this phenomenon lies in that the hierarchical TiO2 nanoribbon/wire spheres in the concurrent system possess the advantages of mitigating the membrane fouling via photocatalytic degrading the organic pollutants relying on their high photocatalytic activities; and keeping high water flux owing to the porous functional layer favorable for water pass through. The experimental results demonstrated that the hierarchical TiO2
Hierarchical Matrix Techniques on Massively Parallel Computers
Izadi, Mohammad
2012-01-01
Hierarchical matrix (H-matrix) techniques can be used to efficiently treat dense matrices. With an H-matrix, the storage requirements and performing all fundamental operations, namely matrix-vector multiplication, matrix-matrix multiplication and matrix inversion can be done in almost linear complexity. In this work, we tried to gain even further speedup for the H-matrix arithmetic by utilizing multiple processors. Our approach towards an H-matrix distribution relies on the s...
A burnup corrected 3-D nodal depletion method for vector and parallel computer architectures
The 2- and 3-D nodal depletion code NOMAD-BC was parallelized and vectorized (3-D only). A 3-D, 2-cycle depletion problem was devised and successfully solved with the NOMAD-BC code in less than 35 seconds on two CPUs of a Cray X-MP/48. This shows a combined vectorization and parallelization speedup of 8.6. The same problem was solved on a 2-CPU 16 MHz SGI workstation in less than one hour, exhibiting a 1.78 speedup over the single processor solution on the same machine. It is shown in this work that complex and detailed burnup computations can be successfully optimized. In addition, the performance achieved demonstrates the possibility of obtaining results within very reasonable times, even on inexpensive workstations. Finally, the small CPU time requirements should make possible the routine evaluation of fuel cycles at great savings of the engineer's time. (author)
Using the CAVE virtual-reality environment as an aid to 3-D electromagnetic field computation
One of the major problems in three-dimensional (3-D) field computation is visualizing the resulting 3-D field distributions. A virtual-reality environment, such as the CAVE, (CAVE Automatic Virtual Environment) is helping to overcome this problem, thus making the results of computation more usable for designers and users of magnets and other electromagnetic devices. As a demonstration of the capabilities of the CAVE, the elliptical multipole wiggler (EMW), an insertion device being designed for the Advanced Photon Source (APS) now being commissioned at Argonne National Laboratory (ANL), wa made visible, along with its fields and beam orbits. Other uses of the CAVE in preprocessing and postprocessing computation for electromagnetic applications are also discussed
Performance assessment of KORAT-3D on the ANL IBM-SP computer
The TENAR code is currently being developed at the Russian Federal Nuclear Center (VNIIEF) as a coupled dynamics code for the simulation of transients in VVER and RBMK systems and other nuclear systems. The neutronic module in this code system is KORAT-3D. This module is also one of the most computationally intensive components of the code system. A parallel version of KORAT-3D has been implemented to achieve the goal of obtaining transient solutions in reasonable computational time, particularly for RBMK calculations that involve the application of >100,000 nodes. An evaluation of the KORAT-3D code performance was recently undertaken on the Argonne National Laboratory (ANL) IBM ScalablePower (SP) parallel computer located in the Mathematics and Computer Science Division of ANL. At the time of the study, the ANL IBM-SP computer had 80 processors. This study was conducted under the auspices of a technical staff exchange program sponsored by the International Nuclear Safety Center (INSC)
Measurement of facial soft tissues thickness using 3D computed tomographic images
To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side. The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. There were no statistically significant differences between the direct measurements and those using the 3D images(p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissue thickness more easily in forensic science and anthropology
A Computer Vision Method for 3D Reconstruction of Curves-Marked Free-Form Surfaces
Xiong Hanwei; Zhang Xiangwei
2001-01-01
Visual method is now broadly used in reverse engineering for 3D reconstruction. Thetraditional computer vision methods are feature-based, i.e., they require that the objects must revealfeatures owing to geometry or textures. For textureless free-form surfaces, dense feature points areadded artificially. In this paper, a new method is put forward combining computer vision with CAGD.The surface is subdivided into N-side Gregory patches using marked curves, and a stereo algorithm isused to reconstruct the curves. Then, the cross boundary tangent vector is computed throughreflectance analysis. At last, the whole surface can be reconstructed by jointing these patches withG1 continuity.
Han Zhou; Jianjun Guo; Peng Li; Tongxiang Fan; Di Zhang; Jinhua Ye
2013-01-01
The development of an “artificial photosynthetic system” (APS) having both the analogous important structural elements and reaction features of photosynthesis to achieve solar-driven water splitting and CO2 reduction is highly challenging. Here, we demonstrate a design strategy for a promising 3D APS architecture as an efficient mass flow/light harvesting network relying on the morphological replacement of a concept prototype-leaf's 3D architecture into perovskite titanates for CO2 photoreduc...
Zhang, Qian; Huang, Shao-Zhuan; Jin, Jun; Liu, Jing; Li, Yu; Wang, Hong-En; Chen, Li-Hua; Wang, Bin-Jie; Su, Bao-Lian
2016-01-01
A highly crystalline three dimensional (3D) bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite constructed by nanoparticles in the range of 50~100 nm via a rapid microwave assisted solvothermal process followed by carbon coating have been synthesized as cathode material for high performance lithium-ion batteries. The abundant 3D macropores allow better penetration of electrolyte to promote Li+ diffusion, the mesopores provide more electrochemical reaction sites and the carbon layers outside LiFePO4 nanoparticles increase the electrical conductivity, thus ultimately facilitating reverse reaction of Fe3+ to Fe2+ and alleviating electrode polarization. In addition, the particle size in nanoscale can provide short diffusion lengths for the Li+ intercalation-deintercalation. As a result, the 3D macro-mesoporous nanosized LiFePO4/C electrode exhibits excellent rate capability (129.1 mA h/g at 2 C; 110.9 mA h/g at 10 C) and cycling stability (87.2% capacity retention at 2 C after 1000 cycles, 76.3% at 5 C after 500 cycles and 87.8% at 10 C after 500 cycles, respectively), which are much better than many reported LiFePO4/C structures. Our demonstration here offers the opportunity to develop nanoscaled hierarchically porous LiFePO4/C structures for high performance lithium-ion batteries through microwave assisted solvothermal method. PMID:27181195
Zhang, Qian; Huang, Shao-Zhuan; Jin, Jun; Liu, Jing; Li, Yu; Wang, Hong-En; Chen, Li-Hua; Wang, Bin-Jie; Su, Bao-Lian
2016-05-01
A highly crystalline three dimensional (3D) bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite constructed by nanoparticles in the range of 50~100 nm via a rapid microwave assisted solvothermal process followed by carbon coating have been synthesized as cathode material for high performance lithium-ion batteries. The abundant 3D macropores allow better penetration of electrolyte to promote Li+ diffusion, the mesopores provide more electrochemical reaction sites and the carbon layers outside LiFePO4 nanoparticles increase the electrical conductivity, thus ultimately facilitating reverse reaction of Fe3+ to Fe2+ and alleviating electrode polarization. In addition, the particle size in nanoscale can provide short diffusion lengths for the Li+ intercalation-deintercalation. As a result, the 3D macro-mesoporous nanosized LiFePO4/C electrode exhibits excellent rate capability (129.1 mA h/g at 2 C; 110.9 mA h/g at 10 C) and cycling stability (87.2% capacity retention at 2 C after 1000 cycles, 76.3% at 5 C after 500 cycles and 87.8% at 10 C after 500 cycles, respectively), which are much better than many reported LiFePO4/C structures. Our demonstration here offers the opportunity to develop nanoscaled hierarchically porous LiFePO4/C structures for high performance lithium-ion batteries through microwave assisted solvothermal method.
PID - 3D: a software to develop mathematical human phantoms for use in computational dosimetry
The PID-3D software, written in Visual C++, contains tools developed for building and editing of three-dimensional geometric figures formed of voxels (volume pixels). These tools were projected to be used, together with those already developed by the Grupo de Dosimetria Numerica (GDN/CNPq), such as the FANTOMAS and DIP software, in computational dosimetry of ionizing radiation. The main objective of this paper is to develop various voxel-based geometric solids to build voxel phantoms (meaning models), anthropomorphic or not. The domain of this technique of development of geometric solids is important for the GDN/CNPq, because it allows the use of just one Monte Carlo code to simulate the transportation, interaction and deposition of radiation in tomographic and mathematical phantoms. Building a particular geometric solid the user needs to inform to the PID-3D software, the location and the size of the parallelepiped that involves it. Each built solid can be saved in a binary file of the type SGI (file containing the size and the numeric values that constitutes the 3D matrix that represents the solid, commonly used by GDN/CNPq). The final mathematical phantom is built starting from these SGI files and the SGI file resulting constitutes a voxel phantom. With this approach the software's user does not have to manipulate the equations and inequalities of the solids that represent the organs and tissues of the phantom. The 3D-PID software, associated with the FANTOMAS and DIP software are tools produced by GDN/CNPq, providing a new technique for building of 3D scenes in dosimetric evaluations using voxel phantoms. To validate the PID-3D software one built, step by step, a phantom similar to the MIRD-5 stylized phantom. (author)
Three-dimensional imaging using computer-generated holograms synthesized from 3-D Fourier spectra
Yatagai, Toyohiko; Miura, Ken-ichi; Sando, Yusuke; Itoh, Masahide [University of Tsukba, Institute of Applied Physics, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan)], E-mail: yatagai@cc.utsunomiya-u.ac.jp
2008-11-01
Computer-generated holograms(CGHs) synthesized from projection images of real existing objects are considered. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD. According to the principles of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel CGH is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary. Moreover, when a color CCD is used in recording, it is easily possible to record and reconstruct colorful objects. Finally, we demonstrate reconstruction of biological objects.
Three-dimensional imaging using computer-generated holograms synthesized from 3-D Fourier spectra
Computer-generated holograms(CGHs) synthesized from projection images of real existing objects are considered. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD. According to the principles of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel CGH is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary. Moreover, when a color CCD is used in recording, it is easily possible to record and reconstruct colorful objects. Finally, we demonstrate reconstruction of biological objects.
Gust Acoustics Computation with a Space-Time CE/SE Parallel 3D Solver
Wang, X. Y.; Himansu, A.; Chang, S. C.; Jorgenson, P. C. E.; Reddy, D. R. (Technical Monitor)
2002-01-01
The benchmark Problem 2 in Category 3 of the Third Computational Aero-Acoustics (CAA) Workshop is solved using the space-time conservation element and solution element (CE/SE) method. This problem concerns the unsteady response of an isolated finite-span swept flat-plate airfoil bounded by two parallel walls to an incident gust. The acoustic field generated by the interaction of the gust with the flat-plate airfoil is computed by solving the 3D (three-dimensional) Euler equations in the time domain using a parallel version of a 3D CE/SE solver. The effect of the gust orientation on the far-field directivity is studied. Numerical solutions are presented and compared with analytical solutions, showing a reasonable agreement.
Sand transverse dune aerodynamics: 3D Coherent Flow Structures from a computational study
Bruno, Luca
2015-01-01
The engineering interest about dune fields is dictated by the their interaction with a number of human infrastructures in arid environments. The aerodynamic behaviour of sand dunes in atmospheric boundary layer belongs to the class of bluff bodies. Because of their simple geometry and their frequent occurrence in desert area, transverse sand dunes are usually adopted in literature as a benchmark to investigate dune aerodynamics by means of both computational or experimental approach, usually in nominally 2D setups. The writers suspect the flow in the wake is characterised by 3D features and affected by wind tunnel setup - e.g. blockage effect, duct side wall boundary layer, incoming velocity profile - when experimental studies are carried out. The present study aims at evaluating the 3D flow features of an idealised transverse dune under different setup conditions by means of computational simulations and to compare the obtained results with experimental measurements.
Paoli Alessandro
2011-02-01
Full Text Available Abstract Background A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides. Methods In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental information into periodontal surgical field. The methodology is based on integrating 3D data of anatomical (impression and cast and preoperative (radiographic template models, obtained by both CT and optical scanning processes. Results A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy of the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed to place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to monitor all the errors, which have been occurring step by step manufacturing the physical templates. Conclusions The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has demonstrated to be a valid support to control the precision of the various physical models adopted and to point out possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the proposed methodology.
Three dimensional field computation software package DE3D and its applications
A software package DE3D, which can be run on PC, for three dimensional electrostatic and magnetostatic field computations is developed in China Institute of Atomic Energy. The features of the code and its applications are introduced. Typical examples are given on the design of a cyclotron magnet and magnetic elements on its beam transport line, which show how the program help the designer to improve his design of products
3D-Workbench : Design and Development of a 3-Dimension Computer Numerical Controlled Machine
Sandru, Andrei
2015-01-01
The purpose of this thesis was to examine and develop a multipurpose Computer Numerical Controlled (CNC) device which would satisfy industrial requirements, but could also be implemented at universities for students to improve and apply their knowledge in different scopes. The topic was specifically chosen because of its close relation to a summer job at a metal factory the author completed and his personal fascination with 3D printers. The project presented in this thesis was commissioned...
3D Vertical Dual-Layer Oxide Memristive Devices for Neuromorphic Computing
Gaba, Siddharth; Sheridan, Patrick; Du, Chao; Wei LU
2014-01-01
Dual-layer resistive switching devices with horizontal W electrodes, vertical Pd electrodes and WOx switching layer formed at the sidewall of the horizontal electrodes have been fabricated and characterized. The devices exhibit well-characterized analog switching characteristics and small mismatch in electrical characteristics for devices formed at the two layers. The three-dimensional (3D) vertical device structure allows higher storage density and larger connectivity for neuromorphic comput...
Computed Tomography and its Application for the 3D Characterization of Coarse Grained Meteorites
Gillies, Donald C.; Engel, H. P.; Carpenter, P. K.
2004-01-01
With judicious selection of parameters, computed tomography can provide high precision density data. Such data can lead to a non-destructive determination of the phases and phase distribution within large solid objects. Of particular interest is the structure of the Mundrabilla meteorite, which has 25 volumes, percent of a sulfide within a metallic meteorite. 3D digital imaging has enabled a quantitative evaluation of the distribution and contiguity of the phases to be determined.
Preoperative evaluation of the saphenous vein by 3-D contrastless computed tomography
Maruyama, Yuji; Imura, Hajime; Shirakawa, Makoto; Ochi, Masami
2013-01-01
Volume-rendering computed tomography (CT) without contrast medium has clearly demonstrated the 3-D mapping of the saphenous vein (SV). Contrastless volume-rendering CT was used to preoperatively evaluate the SV anatomy before coronary artery bypass grafting (CABG). This technique was useful for atypical anatomical variations, such as partial duplication of SV (Case 1) or varicose veins (Case 2). Volume-rendering CT may also help with redo CABG (to determine remaining SV) or during endoscopic ...
Yue, Dan; Lu, Wei; Jin, Lin; Li, Chunyang; Luo, Wen; Wang, Mengnan; Wang, Zhenling; Hao, Jianhua
2014-10-01
Lanthanide doped ZnO mushroom-like 3D hierarchical structures have been fabricated by polyol-mediated method and characterized by various microstructural and optical techniques. The results indicate that the as-prepared ZnO:Ln3+ (Ln = Tb, Eu) samples have a hexagonal phase structure and possess a mushroom-like 3D hierarchical morphology. The length of the whole mushroom from stipe bottom to pileus top is about 1.0 μm, and the diameters of pileus and stipe are about 0.8 μm and 0.4 μm, respectively. It is found that the flow of N2 is the key parameter for the formation of the novel ZnO structure and the addition of (NH4)2HPO4 has a prominent effect on the phase structure and the growth of mushroom-like morphology. The potential mechanism of forming this morphology is proposed. The pileus of the formed mushroom is assembled by several radial ZnO:Ln3+ nanorods, whereas the stipe is composed of over layered ZnO:Ln3+ nanosheets. Moreover, asymmetrical I-V characteristic curves of ZnO:Ln3+ mushrooms indicate that the texture composition of the 3D hierarchical morphology might lead to the asymmetrical transport behavior of electrical conductivity. Lanthanide doped ZnO samples can exhibit red or green emission under the excitation of UV light.Lanthanide doped ZnO mushroom-like 3D hierarchical structures have been fabricated by polyol-mediated method and characterized by various microstructural and optical techniques. The results indicate that the as-prepared ZnO:Ln3+ (Ln = Tb, Eu) samples have a hexagonal phase structure and possess a mushroom-like 3D hierarchical morphology. The length of the whole mushroom from stipe bottom to pileus top is about 1.0 μm, and the diameters of pileus and stipe are about 0.8 μm and 0.4 μm, respectively. It is found that the flow of N2 is the key parameter for the formation of the novel ZnO structure and the addition of (NH4)2HPO4 has a prominent effect on the phase structure and the growth of mushroom-like morphology. The potential
Ding, Taotao; Dai, Jiangnan; Xu, Juan; Wang, Jin; Tian, Wu; Huo, Kaifu; Fang, Yanyan; Chen, Changqing
2015-07-01
A solvothermal method has been employed to synthesize bismuth sulfide (Bi2S3) with three-dimensional (3D) hierarchical architectures. The influences of different types of surfactants and Cl- species on the size and morphology were investigated. A possible formation mechanism was also proposed on the basis of time-dependent experiments. The photoresponse properties show that the conductivity of Bi2S3 micro-flowers is significantly enhanced and the photocurrent is approximately two orders of magnitude larger than the dark current. The response and decay times are estimated to be 142 and 151 ms, respectively. It is expected that hierarchical architectures Bi2S3 may provide a new pathway to develop advanced nanomaterial for high-speed and high-sensitivity photoelectrical switches and photodetecting devices.
Computer assisted 3D pre-operative planning tool for femur fracture orthopedic surgery
Gamage, Pavan; Xie, Sheng Quan; Delmas, Patrice; Xu, Wei Liang
2010-02-01
Femur shaft fractures are caused by high impact injuries and can affect gait functionality if not treated correctly. Until recently, the pre-operative planning for femur fractures has relied on two-dimensional (2D) radiographs, light boxes, tracing paper, and transparent bone templates. The recent availability of digital radiographic equipment has to some extent improved the workflow for preoperative planning. Nevertheless, imaging is still in 2D X-rays and planning/simulation tools to support fragment manipulation and implant selection are still not available. Direct three-dimensional (3D) imaging modalities such as Computed Tomography (CT) are also still restricted to a minority of complex orthopedic procedures. This paper proposes a software tool which allows orthopedic surgeons to visualize, diagnose, plan and simulate femur shaft fracture reduction procedures in 3D. The tool utilizes frontal and lateral 2D radiographs to model the fracture surface, separate a generic bone into the two fractured fragments, identify the pose of each fragment, and automatically customize the shape of the bone. The use of 3D imaging allows full spatial inspection of the fracture providing different views through the manipulation of the interactively reconstructed 3D model, and ultimately better pre-operative planning.
3D animation of facial plastic surgery based on computer graphics
Zhang, Zonghua; Zhao, Yan
2013-12-01
More and more people, especial women, are getting desired to be more beautiful than ever. To some extent, it becomes true because the plastic surgery of face was capable in the early 20th and even earlier as doctors just dealing with war injures of face. However, the effect of post-operation is not always satisfying since no animation could be seen by the patients beforehand. In this paper, by combining plastic surgery of face and computer graphics, a novel method of simulated appearance of post-operation will be given to demonstrate the modified face from different viewpoints. The 3D human face data are obtained by using 3D fringe pattern imaging systems and CT imaging systems and then converted into STL (STereo Lithography) file format. STL file is made up of small 3D triangular primitives. The triangular mesh can be reconstructed by using hash function. Top triangular meshes in depth out of numbers of triangles must be picked up by ray-casting technique. Mesh deformation is based on the front triangular mesh in the process of simulation, which deforms interest area instead of control points. Experiments on face model show that the proposed 3D animation facial plastic surgery can effectively demonstrate the simulated appearance of post-operation.
Modeling tumor/polyp/lesion structure in 3D for computer-aided diagnosis in colonoscopy
Chen, Chao-I.; Sargent, Dusty; Wang, Yuan-Fang
2010-02-01
We describe a software system for building three-dimensional (3D) models from colonoscopic videos. The system is end-to-end in the sense that it takes as input raw image frames-shot during a colon exam-and produces the 3D structure of objects of interest (OOI), such as tumors, polyps, and lesions. We use the structure-from-motion (SfM) approach in computer vision which analyzes an image sequence in which camera's position and aim vary relative to the OOI. The varying pose of the camera relative to the OOI induces the motion-parallax effect which allows 3D depth of the OOI to be inferred. Unlike the traditional SfM system pipeline, our software system contains many check-and-balance mechanisms to ensure robustness, and the analysis from earlier stages of the pipeline is used to guide the later processing stages to better handle challenging medical data. The constructed 3D models allow the pathology (growth and change in both structure and appearance) to be monitored over time.
Parallel computation of 3-D Navier-Stokes flowfields for supersonic vehicles
Ryan, James S.; Weeratunga, Sisira
1993-01-01
Multidisciplinary design optimization of aircraft will require unprecedented capabilities of both analysis software and computer hardware. The speed and accuracy of the analysis will depend heavily on the computational fluid dynamics (CFD) module which is used. A new CFD module has been developed to combine the robust accuracy of conventional codes with the ability to run on parallel architectures. This is achieved by parallelizing the ARC3D algorithm, a central-differenced Navier-Stokes method, on the Intel iPSC/860. The computed solutions are identical to those from conventional machines. Computational speed on 64 processors is comparable to the rate on one Cray Y-MP processor and will increase as new generations of parallel computers become available.
Zeng, Yuze; Flores, Jose F.; Shao, Yu-Cheng; Guo, Jinghua; Chuang, Yi-De; Lu, Jennifer Q.
2016-06-01
We report a new method to reproducibly fabricate functional 3D carbon structures directly on a current collector, e.g. stainless steel. The 3D carbon platform is formed by direct growth of upright arrays of carbon nanofiber bundles on a roughened surface of stainless steel via the seed-assisted approach. Each bundle consists of about 30 individual carbon nanofibers with a diameter of 18 nm on average. We have found that this new platform offers adequate structural integrity. As a result, no reduction of the surface area during downstream chemical functionalization was observed. With a fixed and reproducible 3D structure, the effect of the chemistry of the grafted species on the oxygen reduction reaction has been systematically investigated. This investigation reveals for the first time that non-conductive Si with an appropriate electronic structure distorts the carbon electronic structure and consequently enhances ORR electrocatalysis. The strong interface provides excellent electron connectivity according to electrochemical analysis. This highly reproducible and stable 3D platform can serve as a stepping-stone for the investigation of the effect of carbon surface functionalization on electrochemical reactions in general.We report a new method to reproducibly fabricate functional 3D carbon structures directly on a current collector, e.g. stainless steel. The 3D carbon platform is formed by direct growth of upright arrays of carbon nanofiber bundles on a roughened surface of stainless steel via the seed-assisted approach. Each bundle consists of about 30 individual carbon nanofibers with a diameter of 18 nm on average. We have found that this new platform offers adequate structural integrity. As a result, no reduction of the surface area during downstream chemical functionalization was observed. With a fixed and reproducible 3D structure, the effect of the chemistry of the grafted species on the oxygen reduction reaction has been systematically investigated. This
Computation of 3D steady Navier-Stokes flow with free-surface gravity waves
Lewis, M. R.; Koren, Barry; Raven, H.C.
2003-01-01
In this paper an iterative method for the computation of stationary gravity-wave solutions is investigated, using a novel formulation of the free-surface (FS) boundary-value problem. This method requires the solution of a sequence of stationary Reynolds-Averaged Navier-Stokes subproblems employing the so-called quasi free-surface condition. The numerical performance of this new approach is investigated for two test cases. The first test case involves the computation of the 3D gravity-wave pat...
Implementation of SceneServer : a 3D software assisting developers of computer vision algorithms
Bennet, Fredrik; Fenelius, Stefan
2003-01-01
The purpose behind this thesis is to develop a software (SceneServer) that can generate data such as images and vertex lists from computer models. These models are placed in a virtual environment and they can be controlled either from a graphical user interface (GUI) or from a MATLAB client. Data can be retrieved and processed in MATLAB. By creating a connection between MATLAB and a 3D environment, computer vision algorithms can be designed and tested swiftly, thus giving the developer a powe...
A hybrid method for the computation of quasi-3D seismograms.
Masson, Yder; Romanowicz, Barbara
2013-04-01
The development of powerful computer clusters and efficient numerical computation methods, such as the Spectral Element Method (SEM) made possible the computation of seismic wave propagation in a heterogeneous 3D earth. However, the cost of theses computations is still problematic for global scale tomography that requires hundreds of such simulations. Part of the ongoing research effort is dedicated to the development of faster modeling methods based on the spectral element method. Capdeville et al. (2002) proposed to couple SEM simulations with normal modes calculation (C-SEM). Nissen-Meyer et al. (2007) used 2D SEM simulations to compute 3D seismograms in a 1D earth model. Thanks to these developments, and for the first time, Lekic et al. (2011) developed a 3D global model of the upper mantle using SEM simulations. At the local and continental scale, adjoint tomography that is using a lot of SEM simulation can be implemented on current computers (Tape, Liu et al. 2009). Due to their smaller size, these models offer higher resolution. They provide us with images of the crust and the upper part of the mantle. In an attempt to teleport such local adjoint tomographic inversions into the deep earth, we are developing a hybrid method where SEM computation are limited to a region of interest within the earth. That region can have an arbitrary shape and size. Outside this region, the seismic wavefield is extrapolated to obtain synthetic data at the Earth's surface. A key feature of the method is the use of a time reversal mirror to inject the wavefield induced by distant seismic source into the region of interest (Robertsson and Chapman 2000). We compute synthetic seismograms as follow: Inside the region of interest, we are using regional spectral element software RegSEM to compute wave propagation in 3D. Outside this region, the wavefield is extrapolated to the surface by convolution with the Green's functions from the mirror to the seismic stations. For now, these
Wang, Hongbin; Wang, Ning; Hang, Tao; Li, Ming
2016-05-01
Three-dimensional porous micro-nano hierarchical structure Cu films were prepared by electrochemical deposition with the Hydrogen bubble dynamic template. The morphologies of the deposited films characterized by Scanning Electronic Microscopy (SEM) exhibit a porous micro-nano hierarchical structure, which consists of three levels in different size scales, namely the honeycomb-like microstructure, the dendritic substructure and the nano particles. Besides, the factors which influenced the microscopic morphology were studied, including the deposition time and the additive Ethylene diamine. By measuring the water contact angle, the porous copper films were found to be super-hydrophobic. The maximum of the contact angles could reach as high as 162.1°. An empirical correlation between morphologies and wetting properties was revealed for the first time. The pore diameter increased simultaneously with the deposition time while the contact angle decreased. The mechanism was illustrated by two classical models. Such super-hydrophobic three-dimensional hierarchical micro-nano structure is expected to have practical application in industry.
New solutions and applications of 3D computer tomography image processing
Effenberger, Ira; Kroll, Julia; Verl, Alexander
2008-02-01
As nowadays the industry aims at fast and high quality product development and manufacturing processes a modern and efficient quality inspection is essential. Compared to conventional measurement technologies, industrial computer tomography (CT) is a non-destructive technology for 3D-image data acquisition which helps to overcome their disadvantages by offering the possibility to scan complex parts with all outer and inner geometric features. In this paper new and optimized methods for 3D image processing, including innovative ways of surface reconstruction and automatic geometric feature detection of complex components, are presented, especially our work of developing smart online data processing and data handling methods, with an integrated intelligent online mesh reduction. Hereby the processing of huge and high resolution data sets is guaranteed. Besides, new approaches for surface reconstruction and segmentation based on statistical methods are demonstrated. On the extracted 3D point cloud or surface triangulation automated and precise algorithms for geometric inspection are deployed. All algorithms are applied to different real data sets generated by computer tomography in order to demonstrate the capabilities of the new tools. Since CT is an emerging technology for non-destructive testing and inspection more and more industrial application fields will use and profit from this new technology.
A Computational Model for Suspended Large Rigid Bodies in 3D Unsteady Viscous Flows
Xiao, Feng
1999-11-01
A 3D numerical model for computing large rigid objects suspended in fluid flow has been developed. Rather than calculating the surface pressure upon the solid body, we evaluate the net force and torque based on a volume force formulation. The total effective force is obtained by summing up the forces at the Eulerian grids occupied by the rigid body. The effects of the moving bodies are coupled to the fluid flow by imposing the velocity field of the bodies to the fluid. A Poisson equation is used to compute the pressure over the whole domain. The objects are identified by color functions and calculated by the PPM scheme and a tangent function transformation which scales the transition region of the computed interface to a compact thickness. The model is then implemented on a parallel computer of distributed memory and validated with Stokes and low Reynolds number flows.
Computational fluid dynamics simulations of blood flow regularized by 3D phase contrast MRI
Rispoli, Vinicius C; Nielsen, Jon; Nayak, Krishna S;
2015-01-01
BACKGROUND: Phase contrast magnetic resonance imaging (PC-MRI) is used clinically for quantitative assessment of cardiovascular flow and function, as it is capable of providing directly-measured 3D velocity maps. Alternatively, vascular flow can be estimated from model-based computation fluid...... approach in regularizing 3D flow fields is evaluated. METHODS: The proposed algorithm incorporates both a Newtonian fluid physics model and a linear PC-MRI signal model. The model equations are solved numerically using a modified CFD algorithm. The numerical solution corresponds to the optimal solution of...... dynamics (CFD) calculations. CFD provides arbitrarily high resolution, but its accuracy hinges on model assumptions, while velocity fields measured with PC-MRI generally do not satisfy the equations of fluid dynamics, provide limited resolution, and suffer from partial volume effects. The purpose of this...
The current status of the development of the technology on 3D computer simulation in Japan
The development background and property of the COSIDA, which is the 3D computer simulation system for the analysis on the dismantling procedure of the nuclear facilities in Japan was reviewed. The function of the visualization on the work area, Kinematics analysis and dismantling scenario analysis, which are the sub systems of the COSIDA, has been investigated. The physical, geometrical and radiological properties were modelled in 2D or 3D in the sub system of the visualization of the work area. In the sub system of the kinematics analysis, the command set on the basic work procedure for the control of the motion of the models at a cyber space was driven. The suitability of the command set was estimated by the application of COSIDA to the programming on the motion of the remote dismantling tools for dismantling the components of the nuclear facilities at cyber space
Parallel Adaptive Computation of Blood Flow in a 3D ``Whole'' Body Model
Zhou, M.; Figueroa, C. A.; Taylor, C. A.; Sahni, O.; Jansen, K. E.
2008-11-01
Accurate numerical simulations of vascular trauma require the consideration of a larger portion of the vasculature than previously considered, due to the systemic nature of the human body's response. A patient-specific 3D model composed of 78 connected arterial branches extending from the neck to the lower legs is constructed to effectively represent the entire body. Recently developed outflow boundary conditions that appropriately represent the downstream vasculature bed which is not included in the 3D computational domain are applied at 78 outlets. In this work, the pulsatile blood flow simulations are started on a fairly uniform, unstructured mesh that is subsequently adapted using a solution-based approach to efficiently resolve the flow features. The adapted mesh contains non-uniform, anisotropic elements resulting in resolution that conforms with the physical length scales present in the problem. The effects of the mesh resolution on the flow field are studied, specifically on relevant quantities of pressure, velocity and wall shear stress.
Computation of Edge-Edge-Edge Events Based on Conicoid Theory for 3-D Object Recognition
WU Chenye; MA Huimin
2009-01-01
The availability of a good viewpoint space partition is crucial in three dimensional (3-D) object rec-ognition on the approach of aspect graph. There are two important events depicted by the aspect graph ap-proach, edge-edge-edge (EEE) events and edge-vertex (EV) events. This paper presents an algorithm to compute EEE events by characteristic analysis based on conicoid theory, in contrast to current algorithms that focus too much on EV events and often overlook the importance of EEE events. Also, the paper provides a standard flowchart for the viewpoint space partitioning based on aspect graph theory that makes it suitable for perspective models. The partitioning result best demonstrates the algorithm's efficiency with more valu-able viewpoints found with the help of EEE events, which can definitely help to achieve high recognition rate for 3-D object recognition.
Zhou, Han; Guo, Jianjun; Li, Peng; Fan, Tongxiang; Zhang, Di; Ye, Jinhua
2013-01-01
The development of an "artificial photosynthetic system" (APS) having both the analogous important structural elements and reaction features of photosynthesis to achieve solar-driven water splitting and CO₂ reduction is highly challenging. Here, we demonstrate a design strategy for a promising 3D APS architecture as an efficient mass flow/light harvesting network relying on the morphological replacement of a concept prototype-leaf's 3D architecture into perovskite titanates for CO₂ photoreduction into hydrocarbon fuels (CO and CH₄). The process uses artificial sunlight as the energy source, water as an electron donor and CO₂ as the carbon source, mimicking what real leaves do. To our knowledge this is the first example utilizing biological systems as "architecture-directing agents" for APS towards CO₂ photoreduction, which hints at a more general principle for APS architectures with a great variety of optimized biological geometries. This research would have great significance for the potential realization of global carbon neutral cycle. PMID:23588925
Improved dehydrogenation performance of LiBH4 by 3D hierarchical flower-like MoS2 spheres additives
Zhao, Yan; Liu, Yongchang; Liu, Huiqiao; Kang, Hongyan; Cao, Kangzhe; Wang, Qinghong; Zhang, Chunling; Wang, Yijing; Yuan, Huatang; Jiao, Lifang
2015-12-01
In this work, 3D hierarchical flower-like MoS2 spheres are successfully fabricated via a hydrothermal method followed by a heat treatment. The obtained product is composed of few-layered MoS2 nanosheets with enlarged interlayer distance (ca. 0.66 nm) of the (002) plane. Meanwhile, the hydrogen storage properties of the as-prepared MoS2 ball milled with LiBH4 are systematically investigated. The results of temperature programmed desorption (TPD) and isothermal measurement suggest that the LiBH4-MoS2 (as-prepared) mixture exhibits favorable dehydrogenation properties in both lowering the hydrogen release temperature and improving kinetics of hydrogen release rate. LiBH4-MoS2 (as-prepared) sample (the preparation mass ratio is 1:1) starts to release hydrogen at 171 °C, and roughly 5.6 wt% hydrogen is released within 1 h when isothermally heated to 320 °C, which presents superior dehydrogenation performance compared to that of the bulk LiBH4. The excellent dehydrogenation performance of the LiBH4-MoS2 (as-prepared) mixture may be attributed to the high active site density and enlarged interlayer distance of the MoS2 nanosheets, 3D architectures and hierarchical structures.
Tang, Hua; Huang, Hong; Wang, Xiaoshuai; Wu, Kongqiang; Tang, Guogang; Li, Changsheng
2016-08-01
In this paper, we report a facile and versatile modified hydrothermal method for synthesis of three-dimensional (3D) hierarchical flower-like MoSe2 microspheres using selenium powders and sodium molybdate as raw materials. The as-prepared MoSe2 was investigated for application as an adsorbent for the removal of dye contaminants from water. Power X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscope (XPS) and N2 adsorption-desorption analysis were carried out to study the microstructure of the as-synthesized product. A possible growth mechanism of MoSe2 flower-like microspheres was preliminarily proposed on the basis of observation of a time-dependent morphology evolution process. Moreover, the MoSe2 sample exhibited good adsorption properties, with maximum adsorption capacity of 36.91 mg/g for methyl orange. The adsorption process of methyl orange on 3D hierarchical flower-like MoSe2 microspheres was systematically investigated, which was found to obey the pseudo-second-order rate equation and Langmuir adsorption model.
Using 2D and 3D Computer Games to Detect Colorblindness – a Comparative Study
Laskowski Maciej
2015-12-01
Full Text Available Computer games have accompanied the development of computer technologies since the very beginning. Despite their basic, purely entertainment-targeted appliance, games can also be used for many other purposes. Medical applications are especially interesting, as games (especially different kinds of simulations are widely used for training personnel, e.g. to perform certain procedures or in learning to use equipment. This allows the trainees to gain knowledge and proper habits, as well as test themselves in different situations without any risk. Computer games can also be used as a diagnostic tool, although this topic is still insufficiently researched. This paper discusses the possibility of using serious games for diagnosing color vision disorders, focusing especially on two problems: differences in diagnosing colorblindness using 2D and 3D environments, and the influence of individual features, such as reflex or agility, on the diagnostic process.
Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D
Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.
2016-01-01
This paper presents results from an exploratory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered, focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected and the resulting steady-state analyses using NASA's FUN3D CFD software.
Traveltime computation and imaging from rugged topography in 3D TTI media
Foothill areas with rugged topography are of great potential for oil and gas seismic exploration, but subsurface imaging in these areas is very challenging. Seismic acquisition with larger offset and wider azimuth is necessary for seismic imaging in complex areas. However, the scale anisotropy in this case must be taken into account. To generalize the pre-stack depth migration (PSDM) to 3D transversely isotropic media with vertical symmetry axes (VTI) and tilted symmetry axes (TTI) from rugged topography, a new dynamic programming approach for the first-arrival traveltime computation method is proposed. The first-arrival time on every uniform mesh point is calculated based on Fermat's principle with simple calculus techniques and a systematic mapping scheme. In order to calculate the minimum traveltime, a set of nonlinear equations is solved on each mesh point, where the group velocity is determined by the group angle. Based on the new first-arrival time calculation method, the corresponding PSDM and migration velocity analysis workflow for 3D anisotropic media from rugged surface is developed. Numerical tests demonstrate that the proposed traveltime calculation method is effective in both VTI and TTI media. The migration results for 3D field data show that it is necessary to choose a smooth datum to remove the high wavenumber move-out components for PSDM with rugged topography and take anisotropy into account to achieve better images. (paper)
Coronary computed tomography angiography (coronary CTA) is a powerful non-invasive imaging method to evaluate coronary artery disease. Nowadays, coronary CTA estimated effective radiation dose can be dramatically reduced using state-of-the-art scanners, such as 320-row detector CT (320-CT), without changing coronary CTA diagnostic accuracy. To optimize and further reduce the radiation dose, new iterative reconstruction algorithms were released recently by several CT manufacturers, and now they are used routinely in coronary CTA. This paper presents our first experience using coronary CTA with 320-CT and the Adaptive Iterative Dose Reduction 3D (AIDR-3D). In addition, we describe the current indications for coronary CTA in our practice as well as the acquisition standard protocols and protocols related to CT application for radiation dose reduction. In conclusion, coronary CTA radiation dose can be dramatically reduced following the 'as low as reasonable achievable' principle by combination of exam indication and well-documented technics for radiation dose reduction, such as beta blockers, low-kV, and also the newest iterative dose reduction software as AIDR-3D. (author)
Coupled fully 3D neutron kinetics thermal-hydraulic computations for DNB analysis on PWRs
Departure from Nucleate Boiling (DNB) is one of the major limiting factors of Pressurized Water Reactors (PWRs). Safety requires that occurrence of DNB should be precluded under normal or incidental operating conditions. To perform Main Steam Line Break (MSLB) accident calculations EDF have developed its own numerical tool OSCARD based on: the thermal-hydraulic THYC code for DNB analysis, the neutron kinetics COCCINELLE code for power distribution computations, the thermal-hydraulic CATHARE code to provide boundary conditions analysis with system scale computation. With OSCARD a fully three-dimensional (3D) representation of the core is proposed in conjunction with a two-phase flow porous-body approach (THYC) and two-group diffusion equations in the axial and lateral directions with Doppler and void reactivity feedback effects (COCCINELLE). OSCARD provides EDF with an alternative and independent way of evaluating fuel performance and safety margins. In the licensed approach, the coupled 3D neutron kinetics and thermal-hydraulic part of OSCARD steady computations is used to produce 3D power distribution in the reactor core at the most penalizing moment of the transient. Then this distribution is used as an input for THYC to perform thermal-hydraulic subchannel analysis. This 3 steps approach is used with simple conservative and bounding analysis assumptions, that can not occur in reality. In a prospective approach, OSCARD enables to combine thermal-hydraulic subchannel analysis with the neutron kinetics radial average channel model using a nodalization of one quarter of fuel assembly in order to perform one step DNB analysis. (author)
3-D electromagnetic plasma particle simulations on the Intel Delta parallel computer
A three-dimensional electromagnetic PIC code has been developed on the 512 node Intel Touchstone Delta MIMD parallel computer. This code is based on the General Concurrent PIC algorithm which uses a domain decomposition to divide the computation among the processors. The 3D simulation domain can be partitioned into 1-, 2-, or 3-dimensional sub-domains. Particles must be exchanged between processors as they move among the subdomains. The Intel Delta allows one to use this code for very-large-scale simulations (i.e. over 108 particles and 106 grid cells). The parallel efficiency of this code is measured, and the overall code performance on the Delta is compared with that on Cray supercomputers. It is shown that their code runs with a high parallel efficiency of ≥ 95% for large size problems. The particle push time achieved is 115 nsecs/particle/time step for 162 million particles on 512 nodes. Comparing with the performance on a single processor Cray C90, this represents a factor of 58 speedup. The code uses a finite-difference leap frog method for field solve which is significantly more efficient than fast fourier transforms on parallel computers. The performance of this code on the 128 node Cray T3D will also be discussed
Development of a system for 3D reconstruction of objects using passive computer vision methods
Gec, Sandi
2015-01-01
The main goal of the master thesis is to develop a system for reconstruction of 3D objects from colour images. The main focus is on passive computer vision methods from which we select two, i.e., Stereo vision and Space carving. Both methods require information about camera poses. The camera pose for a given image is estimated from the information obtained by detecting a reference object, i.e., a standard A4 paper sheet. We develop an Android based mobile application to guide a user during im...
The history of visual magic in computers how beautiful images are made in CAD, 3D, VR and AR
Peddie, Jon
2013-01-01
If you have ever looked at a fantastic adventure or science fiction movie, or an amazingly complex and rich computer game, or a TV commercial where cars or gas pumps or biscuits behaved liked people and wondered, ""How do they do that?"", then you've experienced the magic of 3D worlds generated by a computer.3D in computers began as a way to represent automotive designs and illustrate the construction of molecules. 3D graphics use evolved to visualizations of simulated data and artistic representations of imaginary worlds. In order to overcome the processing limitations of the computer, graph
Technical report on hierarchical reservoir computing architectures
Wyffels, Francis; Waegeman, Tim; Schrauwen, Benjamin; Jaeger, Herbert
2012-01-01
One approach for building architectures (of which an overview was given in D.6.1) in AMARSi is to use reservoir computing. Here, untrained (or unsupervised trained) recurrent neural networks are used for motion control by learning simple readouts on the dynamic representation generated by the dynamic RNN system. Although single reservoirs are able to generate rich and tunable control patterns (as demonstrated in D.4.1), to allow composition of motion or high-level control, these modules need ...
Nonlinear hierarchical substructural parallelism and computer architecture
Padovan, Joe
1989-01-01
Computer architecture is investigated in conjunction with the algorithmic structures of nonlinear finite-element analysis. To help set the stage for this goal, the development is undertaken by considering the wide-ranging needs associated with the analysis of rolling tires which possess the full range of kinematic, material and boundary condition induced nonlinearity in addition to gross and local cord-matrix material properties.
Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals’ Behaviour
Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola
2016-01-01
Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs’ behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals’ quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog’s shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non
Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals' Behaviour.
Shanis Barnard
Full Text Available Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs' behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals' quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog's shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is
Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals' Behaviour.
Barnard, Shanis; Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola
2016-01-01
Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs' behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals' quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog's shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non
Computer-controlled dynamic mode multidirectional UV lithography for 3D microfabrication
Computer-controlled dynamic mode multidirectional ultraviolet (UV) lithography has been demonstrated using a collimated UV light source, a substrate-holding stage equipped with two stepper motors (one for tilting and the other for rotation), a controller with programming software and a laptop computer. The tilting and rotational angles of the stage in motion are accurately controlled during UV exposure as programmed by the user to produce complex three-dimensional (3D) microstructures. Process parameters include the initial and final tilting and rotational angles of the stage, and the relative angular velocities of the two motors in addition to the normal fabrication process parameters of UV lithography such as optical dose, baking time, and developing time and condition. Symmetric patterns can be generated by a simple synchronous mode dynamic operation, where both the angular velocities of the tilting motion and the rotating motion are set equal or harmonically related. More complex and non-symmetric patterns can be obtained using a piecewise synchronous mode, where the relationship between the angular velocities of the two motors is described not with a single coefficient but with a set of coefficients. 3D structures fabricated from the synchronous mode operation include the four-leaf clover horn and the cardiac horn while the ones from the piecewise synchronous mode are a vertical triangular slab, a screwed wind vane and arbitrary shape horns. Ray trace simulation has been performed using a mathematical tool in a spherical coordinate system and the simulated 3D patterns show good agreement with the fabricated ones.
Compute extremely low-frequency electromagnetic field exposure by 3-D impendance method
无
2007-01-01
A 3-D impedance method has been introduced to compute the electric currents induced in a human body exposed to extremely low-frequency electromagnetic field.The 3-D impedance method has been deduced from Maxwell equations and is put into the computation and simulation effectively to the visible human body model, which has 196×114×626 cells and more than 40 types of tissues.As the result, two representative cases are investigated.One is exposure of the human body to 100 μT (1 000 mG), the limit recommended by the International Commission on Non-Ionizing Radiation Protection for the public and the other one is the exposure of human body to 0.4 μT (4 mG), the level at which a statistical link appears with a doubled risk of development of childhood leukaemia.The distribution of induced current density can be obtained and the maximum of induced current are found to be 16 mA/m2 and 0.07 mA/m2.
A fission collision separation method has been recently developed to significantly improve the computational efficiency of the COMET response coefficient generator. In this work, the accuracy and efficiency of the new response coefficient generation method is tested in 3D HTTR benchmark problems at both lattice and core levels. In lattice calculations, the surface-to-surface and fission density response coefficients computed by the new method are compared with those directly calculated by the Monte Carlo method. In whole core calculations, the eigenvalues and bundle/pin fission densities predicated by COMET based on the response coefficient libraries generated by the fission collision separation method are compared with those based on the interpolation method as well as the Monte Carlo reference solutions. These comparisons have shown that the new response coefficient generation method is significantly (about 3 times) faster than the interpolations method while its accuracy is close to that of the interpolation method. (author)
A new 3-D integral code for computation of accelerator magnets
For computing accelerator magnets, integral codes have several advantages over finite element codes; far-field boundaries are treated automatically, and computed fields in the bore region satisfy Maxwell's equations exactly. A new integral code employing the edge elements rather than nodal elements has overcome the difficulties associated with earlier integral codes. By the use of field integrals (potential differences) as solution variables, the number of unknowns is reduced to one less than the number of nodes. Two examples, a hollow iron sphere and the dipole magnet of Advanced Photon source injector synchrotron, show the capability of the code. The CPU time requirements are comparable to those of three-dimensional (3-D) finite-element codes. Experiments show that in practice it can realize much of the potential CPU time saving that parallel processing makes possible
Tools for 3D scientific visualization in computational aerodynamics at NASA Ames Research Center
Hardware, software, and techniques used by the Fluid Dynamics Division (NASA) for performing visualization of computational aerodynamics, which can be applied to the visualization of flow fields from computer simulations of fluid dynamics about the Space Shuttle, are discussed. Three visualization techniques applied, post-processing, tracking, and steering, are described, as well as the post-processing software packages used, PLOT3D, SURF (Surface Modeller), GAS (Graphical Animation System), and FAST (Flow Analysis software Toolkit). Using post-processing methods a flow simulation was executed on a supercomputer and, after the simulation was complete, the results were processed for viewing. It is shown that the high-resolution, high-performance three-dimensional workstation combined with specially developed display and animation software provides a good tool for analyzing flow field solutions obtained from supercomputers. 7 refs
A HIERARCHICAL SELF-HEALING SLA FOR CLOUD COMPUTING
Ahmad Mosallanejad
2014-03-01
Full Text Available The service level agreement (SLA is a mutual contract between the service provider and consumer which determines the agreed service level objective (SLO. The common SLA is a plain documental agreement without any relation to other dependent SLAs during the different layers of cloud computing. Hence, the cloud computing environment needs the hierarchical and autonomic SLA. This paper proposes the SH-SLA model to generate a hierarchical self-healing SLA in cloud computing. The self-healing ability contains the SLA monitoring, violation detecting and violation reacting processes. In SH-SLA, the related SLAs communicate with each other hierarchically. The SLA would be able to check its QoS and notify the recent status to dependent SLAs. Furthermore, SH-SLA could prevent or propagate the notified violations by an urgent reaction. Consequently, the service providers have a great chance to prevent the violated SLA before sensing by end users. The SH-SLA model is simulated and the experiment results have presented the violation detection and reaction abilities of the proposed model in cloud computing. Besides, the end users meet the lesser violations in SH-SLA than the common SLA.
A brain-computer interface method combined with eye tracking for 3D interaction.
Lee, Eui Chul; Woo, Jin Cheol; Kim, Jong Hwa; Whang, Mincheol; Park, Kang Ryoung
2010-07-15
With the recent increase in the number of three-dimensional (3D) applications, the need for interfaces to these applications has increased. Although the eye tracking method has been widely used as an interaction interface for hand-disabled persons, this approach cannot be used for depth directional navigation. To solve this problem, we propose a new brain computer interface (BCI) method in which the BCI and eye tracking are combined to analyze depth navigation, including selection and two-dimensional (2D) gaze direction, respectively. The proposed method is novel in the following five ways compared to previous works. First, a device to measure both the gaze direction and an electroencephalogram (EEG) pattern is proposed with the sensors needed to measure the EEG attached to a head-mounted eye tracking device. Second, the reliability of the BCI interface is verified by demonstrating that there is no difference between the real and the imaginary movements for the same work in terms of the EEG power spectrum. Third, depth control for the 3D interaction interface is implemented by an imaginary arm reaching movement. Fourth, a selection method is implemented by an imaginary hand grabbing movement. Finally, for the independent operation of gazing and the BCI, a mode selection method is proposed that measures a user's concentration by analyzing the pupil accommodation speed, which is not affected by the operation of gazing and the BCI. According to experimental results, we confirmed the feasibility of the proposed 3D interaction method using eye tracking and a BCI. PMID:20580646
Multi-level Hierarchical Poly Tree computer architectures
Padovan, Joe; Gute, Doug
1990-01-01
Based on the concept of hierarchical substructuring, this paper develops an optimal multi-level Hierarchical Poly Tree (HPT) parallel computer architecture scheme which is applicable to the solution of finite element and difference simulations. Emphasis is given to minimizing computational effort, in-core/out-of-core memory requirements, and the data transfer between processors. In addition, a simplified communications network that reduces the number of I/O channels between processors is presented. HPT configurations that yield optimal superlinearities are also demonstrated. Moreover, to generalize the scope of applicability, special attention is given to developing: (1) multi-level reduction trees which provide an orderly/optimal procedure by which model densification/simplification can be achieved, as well as (2) methodologies enabling processor grading that yields architectures with varying types of multi-level granularity.
Panitsa, E.; Rosenwald, J. C.; Kappas, C.
1998-10-01
Detailed quality control (QC) protocols are a necessity for modern radiotherapy departments. The established QC protocols for treatment planning systems (TPS) do not include recommendations on the advanced features of three-dimensional (3D) treatment planning, like the dose volume histograms (DVH). In this study, a test protocol for DVH characteristics was developed. The protocol assesses the consistency of the DVH computation to the dose distribution calculated by the same TPS by comparing DVH parameters with values obtained by the isodose distributions. The computation parameters (such as the dimension of the computation grid) that are applied to the TPS during the tests are not fixed but set by the user as if the test represents a typical clinical case. Six commercial TPS were examined with this protocol within the frame of the EC project Dynarad (Biomed I). The results of the intercomparison prove the consistency of the DVH results to the isodose values for most of the examined TPS. However, special attention should be paid when working with cases of adverse conditions such as high dose gradient regions. In these cases, higher errors are derived, especially when an insufficient number of dose calculation points are used for the DVH computation.
Creating computer aided 3D model of spleen and kidney based based on Visible Human Project
To investigate the efficacy of computer aided 3-dimensional (3D) reconstruction technique on visualization and modeling of gross anatomical structures with an affordable methodology applied on the spleen and kidney. From The Visible Human Project Dataset cryosection images, developed by the National Library of Medicine, the spleen and kidney sections were preferred to be used due to their highly distinct contours. The software used for the reconstruction were Surf Driver 3.5.3 for Mac and Cinema 4D X L version 7.1 for Mac OS X. This study was carried out in May 2004 at the Department of Anatomy, Hacettepe University, Ankara, Turkey. As a result of this study, it is determined that these 2 programs could be effectively used both for 3D modeling of the mentioned organs and volumetric analyses on these models. It is also seen that it is possible to hold the physical models of these gross anatomical digital ones with stereolithography technique by means of the data exchange file format provided by the program and present such images as anaglyph. Surf Driver 3.5.3 for Mac OS and Cinema 4 DXL version 7.1 for Mac OS X can be used effectively for reconstruction of gross anatomical structures from serial parallel sections with distinct contours such as spleen and kidney and the animation of models. These software constitute a highly effective way of getting volumetric calculations, spatial relations and morphometrical measurements of reconstructed structures. (author)
Siclari, Michael J.
1988-01-01
A computer code called NCOREL (for Nonconical Relaxation) has been developed to solve for supersonic full potential flows over complex geometries. The method first solves for the conical at the apex and then marches downstream in a spherical coordinate system. Implicit relaxation techniques are used to numerically solve the full potential equation at each subsequent crossflow plane. Many improvements have been made to the original code including more reliable numerics for computing wing-body flows with multiple embedded shocks, inlet flow through simulation, wake model and entropy corrections. Line relaxation or approximate factorization schemes are optionally available. Improved internal grid generation using analytic conformal mappings, supported by a simple geometric Harris wave drag input that was originally developed for panel methods and internal geometry package are some of the new features.
The NCOREL computer program for 3D nonlinear supersonic potential flow computations
Siclari, M. J.
1983-01-01
An innovative computational technique (NCOREL) was established for the treatment of three dimensional supersonic flows. The method is nonlinear in that it solves the nonconservative finite difference analog of the full potential equation and can predict the formation of supercritical cross flow regions, embedded and bow shocks. The method implicitly computes a conical flow at the apex (R = 0) of a spherical coordinate system and uses a fully implicit marching technique to obtain three dimensional cross flow solutions. This implies that the radial Mach number must remain supersonic. The cross flow solutions are obtained by using type dependent transonic relaxation techniques with the type dependency linked to the character of the cross flow velocity (i.e., subsonic/supersonic). The spherical coordinate system and marching on spherical surfaces is ideally suited to the computation of wing flows at low supersonic Mach numbers due to the elimination of the subsonic axial Mach number problems that exist in other marching codes that utilize Cartesian transverse marching planes.
Deng, Weina; Hu, Aiping; Chen, Xiaohua; Zhang, Shiying; Tang, Qunli; Liu, Zheng; Fan, Binbin; Xiao, Kuikui
2016-08-01
A rational 3D hierarchical porous nitrogen-doped aligned carbon nanotubes (HPNACNTs) with well-directed 1D conductive electron paths is designed as scaffold to load sulfur. The HPNACNTs have abundant micropores, mesopores and macropores with a relatively high specific surface area and a large total pore volume. The sulfur-HPNACNTs composite is synthesized for lithium-sulfur batteries by a melt-diffusion of sulfur powders into HPNACNTs scaffolds. Electrochemical tests reveal that the sulfur-HPNACNTs (68.8 wt% sulfur) composite exhibits a high initial discharge capacity of 1340 mAh g-1 at 0.1 C and retains as high as 979 mAh g-1 at 0.2 C after 200 cycles. More importantly, it shows high reversible capacity at high rates (817 mAh g-1 at 5 C). Its enhanced electrochemical performance can be attributed to the excellent electrical conductivity of aligned carbon nanotubes, the synergetic effect of its hierarchical porosity and the restraint of the shuttle effect due to the SxLi … N interactions via the N lone-pair electron.
Computational ghost imaging versus imaging laser radar for 3D imaging
Hardy, Nicholas D
2012-01-01
Ghost imaging has been receiving increasing interest for possible use as a remote-sensing system. There has been little comparison, however, between ghost imaging and the imaging laser radars with which it would be competing. Toward that end, this paper presents a performance comparison between a pulsed, computational ghost imager and a pulsed, floodlight-illumination imaging laser radar. Both are considered for range-resolving (3D) imaging of a collection of rough-surfaced objects at standoff ranges in the presence of atmospheric turbulence. Their spatial resolutions and signal-to-noise ratios are evaluated as functions of the system parameters, and these results are used to assess each system's performance trade-offs. Scenarios in which a reflective ghost-imaging system has advantages over a laser radar are identified.
Fatigue of hybrid glass/carbon composites: 3D computational studies
Dai, Gaoming; Mishnaevsky, Leon
2014-01-01
3D computational simulations of fatigue of hybrid carbon/glass fiber reinforced composites is carried out using X-FEM and multifiber unit cell models. A new software code for the automatic generation of unit cell multifiber models of composites with randomly misaligned fibers of various properties...... and geometrical parameters is developed. With the use of this program code and the X-FEM method, systematic investigations of the effect of microstructure of hybrid composites (fraction of carbon versus glass fibers, misalignment, and interface strength) and the loading conditions (tensile versus...... compression cyclic loading effects) on fatigue behavior of the materials are carried out. It was demonstrated that the higher fraction of carbon fibers in hybrid composites is beneficial for the fatigue lifetime of the composites under tension-tension cyclic loading, but might have negative effect on the...
Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.
Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa
2013-12-01
The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime
Enabling 3D-Liver Perfusion Mapping from MR-DCE Imaging Using Distributed Computing
Benjamin Leporq
2013-01-01
Full Text Available An MR acquisition protocol and a processing method using distributed computing on the European Grid Infrastructure (EGI to allow 3D liver perfusion parametric mapping after Magnetic Resonance Dynamic Contrast Enhanced (MR-DCE imaging are presented. Seven patients (one healthy control and six with chronic liver diseases were prospectively enrolled after liver biopsy. MR-dynamic acquisition was continuously performed in free-breathing during two minutes after simultaneous intravascular contrast agent (MS-325 blood pool agent injection. Hepatic capillary system was modeled by a 3-parameters one-compartment pharmacokinetic model. The processing step was parallelized and executed on the EGI. It was modeled and implemented as a grid workflow using the Gwendia language and the MOTEUR workflow engine. Results showed good reproducibility in repeated processing on the grid. The results obtained from the grid were well correlated with ROI-based reference method ran locally on a personal computer. The speed-up range was 71 to 242 with an average value of 126. In conclusion, distributed computing applied to perfusion mapping brings significant speed-up to quantification step to be used for further clinical studies in a research context. Accuracy would be improved with higher image SNR accessible on the latest 3T MR systems available today.
FURN3D: A computer code for radiative heat transfer in pulverized coal furnaces
Ahluwalia, R.K.; Im, K.H.
1992-08-01
A computer code FURN3D has been developed for assessing the impact of burning different coals on heat absorption pattern in pulverized coal furnaces. The code is unique in its ability to conduct detailed spectral calculations of radiation transport in furnaces fully accounting for the size distributions of char, soot and ash particles, ash content, and ash composition. The code uses a hybrid technique of solving the three-dimensional radiation transport equation for absorbing, emitting and anisotropically scattering media. The technique achieves an optimal mix of computational speed and accuracy by combining the discrete ordinate method (S{sub 4}), modified differential approximation (MDA) and P, approximation in different range of optical thicknesses. The code uses spectroscopic data for estimating the absorption coefficients of participating gases C0{sub 2}, H{sub 2}0 and CO. It invokes Mie theory for determining the extinction and scattering coefficients of combustion particulates. The optical constants of char, soot and ash are obtained from dispersion relations derived from reflectivity, transmissivity and extinction measurements. A control-volume formulation is adopted for determining the temperature field inside the furnace. A simple char burnout model is employed for estimating heat release and evolution of particle size distribution. The code is written in Fortran 77, has modular form, and is machine-independent. The computer memory required by the code depends upon the number of grid points specified and whether the transport calculations are performed on spectral or gray basis.
FURN3D: A computer code for radiative heat transfer in pulverized coal furnaces
Ahluwalia, R.K.; Im, K.H.
1992-08-01
A computer code FURN3D has been developed for assessing the impact of burning different coals on heat absorption pattern in pulverized coal furnaces. The code is unique in its ability to conduct detailed spectral calculations of radiation transport in furnaces fully accounting for the size distributions of char, soot and ash particles, ash content, and ash composition. The code uses a hybrid technique of solving the three-dimensional radiation transport equation for absorbing, emitting and anisotropically scattering media. The technique achieves an optimal mix of computational speed and accuracy by combining the discrete ordinate method (S[sub 4]), modified differential approximation (MDA) and P, approximation in different range of optical thicknesses. The code uses spectroscopic data for estimating the absorption coefficients of participating gases C0[sub 2], H[sub 2]0 and CO. It invokes Mie theory for determining the extinction and scattering coefficients of combustion particulates. The optical constants of char, soot and ash are obtained from dispersion relations derived from reflectivity, transmissivity and extinction measurements. A control-volume formulation is adopted for determining the temperature field inside the furnace. A simple char burnout model is employed for estimating heat release and evolution of particle size distribution. The code is written in Fortran 77, has modular form, and is machine-independent. The computer memory required by the code depends upon the number of grid points specified and whether the transport calculations are performed on spectral or gray basis.
3D Navier-Stokes Time Accurate Solutions Using Multipartitioning Parallel Computation Methodology
Zha, Ge-Cheng
1998-01-01
A parallel CFD code solving 3D time accurate Navier-Stokes equations with multipartitioning parallel Methodology is being developed in collaboration with Ohio State University within the Air Vehicle Directorate, at Wright Patterson Air Force Base. The advantage of the multipartitioning parallel method is that the domain decomposition will not introduce domain boundaries for the implicit operators. A ring structure data communication is employed so that the implicit time accurate method can be implemented for multi-processors with the same accuracy as for the single processor. No sub-iteration is needed at the domain boundaries. The code has been validated for some typical unsteady flows, which include Coutte Flow, flow passing a cylinder. The code now is being employed for a large scale time accurate wall jet transient flow computation. 'ne preliminary results are promising. The mesh has been refined to capture more details of the flow field. The mesh refinement computation is in progress and would be difficult to successfully implement without the parallel computation techniques used. A modified version of the code with more efficient inversion of the diagonalized block matrix is currently being tested.
Highlights: • Novel 3D SnO flowers self-assembled by 2D nano-leaves were synthesized by hydrothermal method. • The SnO nano-leaf is of single crystalline nature. • The band gap of 2.59 eV of as-prepared products was obtained. • The as-synthesized material will be a promising photocatalytic material. - Abstract: In this report, the novel 3D SnO flower-like hierarchical architectures self-assembled by 2D SnO nano-leaves are successfully synthesized via template-free hydrothermal approach under facile conditions. The high-resolution transmission electron microscopy results demonstrate that the 2D nano-leaves structure is of single crystalline nature. The band gap 2.59 eV for prepared product is obtained from UV–vis diffuse reflectance spectrum. The photocatalysis of the as prepared SnO for degrading methyl orange (MO) has been studied. A good photocatalytic activity is obtained and the mechanism is discussed in detail. Results indicate that the SnO nanostructures are the potential candidates for photocatalyst applications
Cui, Yongkui; Wang, Fengping, E-mail: fpwang@ustb.edu.cn; Iqbal, M. Zubair; Wang, Ziya; Li, Yan; Tu, Jianhai
2015-10-15
Highlights: • Novel 3D SnO flowers self-assembled by 2D nano-leaves were synthesized by hydrothermal method. • The SnO nano-leaf is of single crystalline nature. • The band gap of 2.59 eV of as-prepared products was obtained. • The as-synthesized material will be a promising photocatalytic material. - Abstract: In this report, the novel 3D SnO flower-like hierarchical architectures self-assembled by 2D SnO nano-leaves are successfully synthesized via template-free hydrothermal approach under facile conditions. The high-resolution transmission electron microscopy results demonstrate that the 2D nano-leaves structure is of single crystalline nature. The band gap 2.59 eV for prepared product is obtained from UV–vis diffuse reflectance spectrum. The photocatalysis of the as prepared SnO for degrading methyl orange (MO) has been studied. A good photocatalytic activity is obtained and the mechanism is discussed in detail. Results indicate that the SnO nanostructures are the potential candidates for photocatalyst applications.
Yuan, Shuang; Wang, Sai; Li, Lin; Zhu, Yun-hai; Zhang, Xin-bo; Yan, Jun-min
2016-04-13
Development of an anode material with high performance and low cost is crucial for implementation of next-generation Na-ion batteries (NIBs) electrode, which is proposed to meet the challenges of large scale renewable energy storage. Metal chalcogenides are considered as promising anode materials for NIBs due to their high theoretical capacity, low cost, and abundant sources. Unfortunately, their practical application in NIBs is still hindered because of low conductivity and morphological collapse caused by their volume expansion and shrinkage during Na(+) intercalation/deintercalation. To solve the daunting challenges, herein, we fabricated novel three-dimensional (3D) Cu2NiSnS4 nanoflowers (CNTSNs) as a proof-of-concept experiment using a facile and low-cost method. Furthermore, homogeneous integration with reduced graphene oxide nanosheets (RGNs) endows intrinsically insulated CNTSNs with superior electrochemical performances, including high specific capacity (up to 837 mAh g(-1)), good rate capability, and long cycling stability, which could be attributed to the unique 3D hierarchical structure providing fast ion diffusion pathway and high contact area at the electrode/electrolyte interface. PMID:26986821
Beane, Andy
2012-01-01
The essential fundamentals of 3D animation for aspiring 3D artists 3D is everywhere--video games, movie and television special effects, mobile devices, etc. Many aspiring artists and animators have grown up with 3D and computers, and naturally gravitate to this field as their area of interest. Bringing a blend of studio and classroom experience to offer you thorough coverage of the 3D animation industry, this must-have book shows you what it takes to create compelling and realistic 3D imagery. Serves as the first step to understanding the language of 3D and computer graphics (CG)Covers 3D anim
Madura, Thomas I.; Clementel, Nicola; Gull, Theodore R.; Kruip, Chael J. H.; Paardekooper, Jan-Pieter
2015-01-01
We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (>120 M_Sun), highly eccentric (e ~ 0.9) binary star system Eta Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF journal publication and the benefits of using 3D visualization and 3D printing as tools to analyze data from multidimensional numerical simulations. Using a consumer-grade 3D printer (Make...
The accuracy of Single-Photon Emission Computed Tomography images is degraded by physical effects, namely photon attenuation, Compton scatter and spatially varying collimator response. The 3D nature of these effects is usually neglected by the methods used to correct for these effects. To deal with the 3D nature of the problem, a 3D projector modeling the spread of photons in 3D can be used in iterative tomographic reconstruction. The 3D projector can be estimated analytically with some approximations, or using precise Monte Carlo simulations. This latter approach has not been applied to fully 3D reconstruction yet due to impractical storage and computation time. The goal of this paper was to determine the gain to be expected from fully 3D Monte Carlo (F3DMC) modeling of the projector in iterative reconstruction, compared to conventional 2D and 3D reconstruction methods. As a proof-of-concept, two small datasets were considered. The projections of the two phantoms were simulated using the Monte Carlo simulation code GATE, as well as the corresponding projector, by taking into account all physical effects (attenuation, scatter, camera point spread function) affecting the imaging process. F3DMC was implemented by using this 3D projector in a maximum likelihood expectation maximization (MLEM) iterative reconstruction. To assess the value of F3DMC, data were reconstructed using four methods: filtered backprojection, MLEM without attenuation correction (MLEM), MLEM with attenuation correction, Jaszczak scatter correction and 3D correction for depth-dependent spatial resolution using an analytical model (MLEMC) and F3DMC. Our results suggest that F3DMC improves mainly imaging sensitivity and signal-to-noise ratio (SNR): sensitivity is multiplied by about 103 and SNR is increased by 20-70% compared to MLEMC. Computation of a more robust projector and application of the method on more realistic datasets are currently under investigation
A small scale experimental facility was designed to study the thermal hydraulic phenomena in the Reactor Cavity Cooling System (RCCS). The facility was scaled down from the full scale RCCS system by applying scaling laws. A set of RELAP5-3D simulations were performed to confirm the scaling calculations, and to refine and optimize the facility's configuration, instrumentation selection, and layout. Computational Fluid Dynamics (CFD) calculations using StarCCM+ were performed in order to study the flow patterns and two-phase water behavior in selected locations of the facility where expected complex flow structure occurs. (author)
Potential hazards of viewing 3-D stereoscopic television, cinema and computer games: a review.
Howarth, Peter A
2011-03-01
The visual stimulus provided by a 3-D stereoscopic display differs from that of the real world because the image provided to each eye is produced on a flat surface. The distance from the screen to the eye remains fixed, providing a single focal distance, but the introduction of disparity between the images allows objects to be located geometrically in front of, or behind, the screen. Unlike in the real world, the stimulus to accommodation and the stimulus to convergence do not match. Although this mismatch is used positively in some forms of Orthoptic treatment, a number of authors have suggested that it could negatively lead to the development of asthenopic symptoms. From knowledge of the zone of clear, comfortable, single binocular vision one can predict that, for people with normal binocular vision, adverse symptoms will not be present if the discrepancy is small, but are likely if it is large, and that what constitutes 'large' and 'small' are idiosyncratic to the individual. The accommodation-convergence mismatch is not, however, the only difference between the natural and the artificial stimuli. In the former case, an object located in front of, or behind, a fixated object will not only be perceived as double if the images fall outside Panum's fusional areas, but it will also be defocused and blurred. In the latter case, however, it is usual for the producers of cinema, TV or computer game content to provide an image that is in focus over the whole of the display, and as a consequence diplopic images will be sharply in focus. The size of Panum's fusional area is spatial frequency-dependent, and because of this the high spatial frequencies present in the diplopic 3-D image will provide a different stimulus to the fusion system from that found naturally. PMID:21309798
Zhonghua Sun
2011-01-01
Multislice computed tomography (CT) has been widely used in clinical practice for the diagnosis of cardiovascular disease due to its reduced invasiveness and high spatial and temporal resolution.As a reliable alternative to conventional angiography,multislice CT angiography has been recognized as the method of choice for detecting and diagnosing head and neck vascular disease,abdominal aortic aneurysm,aortic dissection,and pulmonary embolism.In patients with suspected coronary artery disease,although invasive coronary angiography still remains as the gold standard technique,multislice CT angiography demonstrates high diagnostic accuracy; in selected patients,it is considered as the first-line technique.The imaging diagnosis of cardiovascular disease is based on a combination of two-dimensional (2D) and three-dimensional (3D) visualization tools to enhance the diagnostic value.This is facilitated by reconstructed visualizations which provide additional information about the extent of the disease,an accurate assessment of the spatial relationship between normal structures and pathological changes,and pre-operative planning and post-procedure follow-up.The aim of the present article is to present an overview of the diagnostic performance of various 2D and 3D CT visualizations in cardiovascular disease,including multiplanar reformation,maximum intensity projection,volume rendering,and virtual intravascular endoscopy.The recognition of the potential value of these visualizations will assist clinicians in efficiently using the muitislice CT imaging modality for the diagnostic management of patients with cardiovascular disease.
Computer-aided detection of cancer in automated 3-D breast ultrasound.
Tan, Tao; Platel, Bram; Mus, Roel; Tabar, László; Mann, Ritse M; Karssemeijer, Nico
2013-09-01
Automated 3-D breast ultrasound (ABUS) has gained a lot of interest and may become widely used in screening of dense breasts, where sensitivity of mammography is poor. However, reading ABUS images is time consuming, and subtle abnormalities may be missed. Therefore, we are developing a computer aided detection (CAD) system to help reduce reading time and prevent errors. In the multi-stage system we propose, segmentations of the breast, the nipple and the chestwall are performed, providing landmarks for the detection algorithm. Subsequently, voxel features characterizing coronal spiculation patterns, blobness, contrast, and depth are extracted. Using an ensemble of neural-network classifiers, a likelihood map indicating potential abnormality is computed. Local maxima in the likelihood map are determined and form a set of candidates in each image. These candidates are further processed in a second detection stage, which includes region segmentation, feature extraction and a final classification. On region level, classification experiments were performed using different classifiers including an ensemble of neural networks, a support vector machine, a k-nearest neighbors, a linear discriminant, and a gentle boost classifier. Performance was determined using a dataset of 238 patients with 348 images (views), including 169 malignant and 154 benign lesions. Using free response receiver operating characteristic (FROC) analysis, the system obtains a view-based sensitivity of 64% at 1 false positives per image using an ensemble of neural-network classifiers. PMID:23693128
Trelease, R B
1996-01-01
Advances in computer visualization and user interface technologies have enabled development of "virtual reality" programs that allow users to perceive and to interact with objects in artificial three-dimensional environments. Such technologies were used to create an image database and program for studying the human skull, a specimen that has become increasingly expensive and scarce. Stereoscopic image pairs of a museum-quality skull were digitized from multiple views. For each view, the stereo pairs were interlaced into a single, field-sequential stereoscopic picture using an image processing program. The resulting interlaced image files are organized in an interactive multimedia program. At run-time, gray-scale 3-D images are displayed on a large-screen computer monitor and observed through liquid-crystal shutter goggles. Users can then control the program and change views with a mouse and cursor to point-and-click on screen-level control words ("buttons"). For each view of the skull, an ID control button can be used to overlay pointers and captions for important structures. Pointing and clicking on "hidden buttons" overlying certain structures triggers digitized audio spoken word descriptions or mini lectures. PMID:8793223
Computer-assisted diagnostic system for neurodegenerative dementia using brain SPECT and 3D-SSP
Ishii, Kazunari; Kanda, Tomonori; Uemura, Takafumi; Miyamoto, Naokazu; Yoshikawa, Toshiki [Hyogo Brain and Heart Center, Department of Radiology and Nuclear Medicine, Himeji, Hyogo (Japan); Shimada, Kenichi; Ohkawa, Shingo [Hyogo Brain and Heart Center, Institute for Aging Brain and Cognitive Disorders, Himeji, Hyogo (Japan); Minoshima, Satoshi [University of Washington, Radiology and Bioengineering, Department of Radiology, Seattle, WA (United States)
2009-05-15
To develop a computer-assisted automated diagnostic system to distinguish among Alzheimer disease (AD), dementia with Lewy bodies (DLB), and other degenerative disorders in patients with mild dementia. Single photon emission computed tomography (SPECT) images with injection of N-Isopropyl-p-[{sup 123}I]iodoamphetamine (IMP) were obtained from patients with mild degenerative dementia. First, datasets from 20 patients mild AD, 15 patients with dementia with DLB, and 17 healthy controls were used to develop an automated diagnosing system based on three-dimensional stereotactic surface projections (3D-SSP). AD- and DLB-specific regional templates were created using 3D-SSP, and critical Z scores in the templates were established. Datasets from 50 AD patients, 8 DLB patients, and 10 patients with non-AD/DLB type degenerative dementia (5 with frontotemporal dementia and 5 with progressive supranuclear palsy) were then used to test the diagnostic accuracy of the optimized automated system in comparison to the diagnostic interpretation of conventional IMP-SPECT images. These comparisons were performed to differentiate AD and DLB from non-AD/DLB and to distinguish AD from DLB. A receiver operating characteristic (ROC) analysis was performed. The area under the ROC curve (Az) and the accuracy of the automated diagnosis system were 0.89 and 82%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 65%, respectively, for AD vs. DLB patients. The mean Az and the accuracy of the visual inspection were 0.84 and 77%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 65%, respectively, for AD vs. DLB patients. The mean Az and the accuracy of the combination of visual inspection and this system were 0.96 and 91%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 66%, respectively, for AD vs. DLB patients. The system developed in the present study achieved as good discrimination of AD, DLB, and other degenerative disorders in patients with mild
Computer-assisted diagnostic system for neurodegenerative dementia using brain SPECT and 3D-SSP
To develop a computer-assisted automated diagnostic system to distinguish among Alzheimer disease (AD), dementia with Lewy bodies (DLB), and other degenerative disorders in patients with mild dementia. Single photon emission computed tomography (SPECT) images with injection of N-Isopropyl-p-[123I]iodoamphetamine (IMP) were obtained from patients with mild degenerative dementia. First, datasets from 20 patients mild AD, 15 patients with dementia with DLB, and 17 healthy controls were used to develop an automated diagnosing system based on three-dimensional stereotactic surface projections (3D-SSP). AD- and DLB-specific regional templates were created using 3D-SSP, and critical Z scores in the templates were established. Datasets from 50 AD patients, 8 DLB patients, and 10 patients with non-AD/DLB type degenerative dementia (5 with frontotemporal dementia and 5 with progressive supranuclear palsy) were then used to test the diagnostic accuracy of the optimized automated system in comparison to the diagnostic interpretation of conventional IMP-SPECT images. These comparisons were performed to differentiate AD and DLB from non-AD/DLB and to distinguish AD from DLB. A receiver operating characteristic (ROC) analysis was performed. The area under the ROC curve (Az) and the accuracy of the automated diagnosis system were 0.89 and 82%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 65%, respectively, for AD vs. DLB patients. The mean Az and the accuracy of the visual inspection were 0.84 and 77%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 65%, respectively, for AD vs. DLB patients. The mean Az and the accuracy of the combination of visual inspection and this system were 0.96 and 91%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 66%, respectively, for AD vs. DLB patients. The system developed in the present study achieved as good discrimination of AD, DLB, and other degenerative disorders in patients with mild dementia
Madura, T. I.; Clementel, N.; Gull, T. R.; Kruip, C. J. H.; Paardekooper, J.-P.
2015-06-01
We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (≳120 M⊙), highly eccentric (e ˜ 0.9) binary star system η Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF (Portable Document Format) journal publication and the benefits of using 3D visualization and 3D printing as tools to analyse data from multidimensional numerical simulations. Using a consumer-grade 3D printer (MakerBot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics simulations of η Carinae's inner (r ˜ 110 au) wind-wind collision interface at multiple orbital phases. The 3D prints and visualizations reveal important, previously unknown `finger-like' structures at orbital phases shortly after periastron (φ ˜ 1.045) that protrude radially outwards from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. thin-shell, Rayleigh-Taylor) that arise at the interface between the radiatively cooled layer of dense post-shock primary-star wind and the fast (3000 km s-1), adiabatic post-shock companion-star wind. The success of our work and easy identification of previously unrecognized physical features highlight the important role 3D printing and interactive graphics can play in the visualization and understanding of complex 3D time-dependent numerical simulations of astrophysical phenomena.
Li, Zhenwei; Sun, Jianyong; Zhang, Jianguo
2012-02-01
As more and more CT/MR studies are scanning with larger volume of data sets, more and more radiologists and clinician would like using PACS WS to display and manipulate these larger data sets of images with 3D rendering features. In this paper, we proposed a design method and implantation strategy to develop 3D image display component not only with normal 3D display functions but also with multi-modal medical image fusion as well as compute-assisted diagnosis of coronary heart diseases. The 3D component has been integrated into the PACS display workstation of Shanghai Huadong Hospital, and the clinical practice showed that it is easy for radiologists and physicians to use these 3D functions such as multi-modalities' (e.g. CT, MRI, PET, SPECT) visualization, registration and fusion, and the lesion quantitative measurements. The users were satisfying with the rendering speeds and quality of 3D reconstruction. The advantages of the component include low requirements for computer hardware, easy integration, reliable performance and comfortable application experience. With this system, the radiologists and the clinicians can manipulate with 3D images easily, and use the advanced visualization tools to facilitate their work with a PACS display workstation at any time.
Performance Assessment of Three Rendering Engines in 3D Computer Graphics Software
Žan Vidmar
2015-03-01
Full Text Available The aim of the research was the determination of testing conditions and visual and numerical evaluation of renderings made with three different rendering engines in Maya software, which is widely used for educational and computer art purposes. In the theoretical part the overview of light phenomena and their simulation in virtual space is presented. This is followed by a detailed presentation of the main rendering methods and the results and limitations of their applications to 3D objects. At the end of the theoretical part the importance of a proper testing scene and especially the role of Cornell box are explained. In the experimental part the terms and conditions as well as hardware and software used for the research are presented. This is followed by a description of the procedures, where we focused on the rendering quality and time, which enabled the comparison of settings of different render engines and determination of conditions for further rendering of testing scenes. The experimental part continued with rendering a variety of simple virtual scenes including Cornell box and virtual object with different materials and colours. Apart from visual evaluation, which was the starting point for comparison of renderings, a procedure for numerical estimation and colour deviations of renderings using the selected regions of interest in the final images is presented.
Computed Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding
Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.
2005-01-01
In friction stir welding (FSW), a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and is carried with the macro-flow of the weld metal. By using CT images, a 3-dimensional (3D) image of the lead flow pattern can be reconstructed. CT imaging was found to be a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.
High resolution 3D imaging of bump-bonds by means of synchrotron radiation computed laminography
Cecilia, A.; Hamann, E.; Koenig, T.; Xu, F.; Cheng, Y.; Helfen, L.; Ruat, M.; Scheel, M.; Zuber, M.; Baumbach, T.; Fauler, A.; Fiederle, M.
2013-12-01
During the flip-chip bonding process of a semiconductor sensor onto readout electronics, a formation of defects may take place, like solder joint displacements, voids, cracks, pores and bridges. This may result in blind spots on the detector, which are insensitive to photons and thus reduce the detector performance. In this work, the flip-chip interconnections of selected CdTe and GaAs Medipix detectors were investigated by synchrotron radiation computed laminography at a micrometer scale. The analysis of the volume rendering proved the presence of voids in the CdTe sensor flip-chip interconnections, with sizes between 3 μm and 9 μm. These voids can be harmful for the long term use of the device, because their presence weakens the adhesive strength between a contact and the readout electronics. Consequently, their formation needs to be avoided. The GaAs Medipix detectors investigated include two sensors that were produced with different flip-chip methods. The comparison of the 3D renderings of the bump-bond interconnections in the two GaAs sensors demonstrated the presence of a misalignment in the range of 5-12 μm between pixel passivation and bump-bonds in the detector produced with an older technique. In contrast to this, no misalignment was observed for the most recently produced detector. The only remarkable observation is the presence of ``satellites'' of solder that do not compromise the detector operation.
High resolution 3D imaging of bump-bonds by means of synchrotron radiation computed laminography
During the flip-chip bonding process of a semiconductor sensor onto readout electronics, a formation of defects may take place, like solder joint displacements, voids, cracks, pores and bridges. This may result in blind spots on the detector, which are insensitive to photons and thus reduce the detector performance. In this work, the flip-chip interconnections of selected CdTe and GaAs Medipix detectors were investigated by synchrotron radiation computed laminography at a micrometer scale. The analysis of the volume rendering proved the presence of voids in the CdTe sensor flip-chip interconnections, with sizes between 3 μm and 9 μm. These voids can be harmful for the long term use of the device, because their presence weakens the adhesive strength between a contact and the readout electronics. Consequently, their formation needs to be avoided. The GaAs Medipix detectors investigated include two sensors that were produced with different flip-chip methods. The comparison of the 3D renderings of the bump-bond interconnections in the two GaAs sensors demonstrated the presence of a misalignment in the range of 5–12 μm between pixel passivation and bump-bonds in the detector produced with an older technique. In contrast to this, no misalignment was observed for the most recently produced detector. The only remarkable observation is the presence of ''satellites'' of solder that do not compromise the detector operation
Detecting and visualizing internal 3D oleoresin in agarwood by means of micro-computed tomography
Detection and analysis of oleoresin is particularly significant since the commercial value of agarwood is related to the quantity of oleoresins that are present. A modern technique of non-destructive may reach the interior region of the wood. Currently, tomographic image data in particular is most commonly visualized in three dimensions using volume rendering. The aim of this paper is to explore the potential of high resolution non-destructive 3D visualization technique, X-ray micro-computed tomography, as imaging tools to visualize micro-structure oleoresin in agarwood. Investigations involving desktop X-ray micro-tomography system on high grade agarwood sample, performed at the Centre of Tomography in Nuclear Malaysia, demonstrate the applicability of the method. Prior to experiments, a reference test was conducted to stimulate the attenuation of oleoresin in agarwood. Based on the experiment results, micro-CT imaging with voxel size 7.0 μm is capable to of detecting oleoresin and pores in agarwood. This imaging technique, although sophisticated can be used for standard development especially in grading of agarwood for commercial activities. (author)
Helfer, Talita Micheletti; Peixoto, Alberto Borges; Tonni, Gabriele; Araujo Júnior, Edward
2016-09-01
Craniosynostosis is defined as the process of premature fusion of one or more of the cranial sutures. It is a common condition that occurs in about 1 to 2,000 live births. Craniosynostosis may be classified in primary or secondary. It is also classified as nonsyndromic or syndromic. According to suture commitment, craniosynostosis may affect a single suture or multiple sutures. There is a wide range of syndromes involving craniosynostosis and the most common are Apert, Pffeifer, Crouzon, Shaethre-Chotzen and Muenke syndromes. The underlying etiology of nonsyndromic craniosynostosis is unknown. Mutations in the fibroblast growth factor (FGF) signalling pathway play a crucial role in the etiology of craniosynostosis syndromes. Prenatal ultrasound`s detection rate of craniosynostosis is low. Nowadays, different methods can be applied for prenatal diagnosis of craniosynostosis, such as two-dimensional (2D) and three-dimensional (3D) ultrasound, magnetic resonance imaging (MRI), computed tomography (CT) scan and, finally, molecular diagnosis. The presence of craniosynostosis may affect the birthing process. Fetuses with craniosynostosis also have higher rates of perinatal complications. In order to avoid the risks of untreated craniosynostosis, children are usually treated surgically soon after postnatal diagnosis. PMID:27622416
Detectability of hepatic tumors during 3D post-processed ultrafast cone-beam computed tomography
To evaluate hepatic tumor detection using ultrafast cone-beam computed tomography (UCBCT) cross-sectional and 3D post-processed image datasets.657 patients were examined using UCBCT during hepatic transarterial chemoembolization (TACE), and data were collected retrospectively from January 2012 to September 2014. Tumor detectability, diagnostic ability, detection accuracy and sensitivity were examined for different hepatic tumors using UCBCT cross-sectional, perfusion blood volume (PBV) and UCBCT–MRI (magnetic resonance imaging) fused image datasets. Appropriate statistical tests were used to compare collected sample data.Fused image data showed the significantly higher (all P < 0.05) diagnostic ability for hepatic tumors compared to UCBCT or PBV image data. The detectability of small hepatic tumors (<5 mm) was significantly reduced (all P < 0.05) using UCBCT cross-sectional images compared to MRI or fused image data; however, PBV improved tumor detectability using a color display. Fused image data produced 100% tumor sensitivity due to the simultaneous availability of MRI and UCBCT information during tumor diagnosis.Fused image data produced excellent hepatic tumor sensitivity, detectability and diagnostic ability compared to other datasets assessed. Fused image data is extremely reliable and useful compared to UCBCT cross-sectional or PBV image datasets to depict hepatic tumors during TACE. Partial anatomical visualization on cross-sectional images was compensated by fused image data during tumor diagnosis. (paper)
Computer-assisted 3D kinematic analysis of all leg joints in walking insects.
John A Bender
Full Text Available High-speed video can provide fine-scaled analysis of animal behavior. However, extracting behavioral data from video sequences is a time-consuming, tedious, subjective task. These issues are exacerbated where accurate behavioral descriptions require analysis of multiple points in three dimensions. We describe a new computer program written to assist a user in simultaneously extracting three-dimensional kinematics of multiple points on each of an insect's six legs. Digital video of a walking cockroach was collected in grayscale at 500 fps from two synchronized, calibrated cameras. We improved the legs' visibility by painting white dots on the joints, similar to techniques used for digitizing human motion. Compared to manual digitization of 26 points on the legs over a single, 8-second bout of walking (or 106,496 individual 3D points, our software achieved approximately 90% of the accuracy with 10% of the labor. Our experimental design reduced the complexity of the tracking problem by tethering the insect and allowing it to walk in place on a lightly oiled glass surface, but in principle, the algorithms implemented are extensible to free walking. Our software is free and open-source, written in the free language Python and including a graphical user interface for configuration and control. We encourage collaborative enhancements to make this tool both better and widely utilized.
First refraction enhanced 3D computed tomography. Application to metal matrix composites
For the first time Metal Matrix Composites (MMC) have been investigated by 3D Computed Tomography combined with enhanced interface contrast due to X-ray refraction. X-ray refraction is a relatively new approach for the characterization of advanced materials. The related techniques of Refraction Topography and Refraction Computed Tomography have been developed and applied at our laboratory during the last decade to meet the actual demand for improved non-destructive characterization of high performance composites, ceramics and other low density materials and components. X-ray refraction occurs, when X-rays crosses interfaces of spherical or cylindrical shape (e.g. pores or fibres) in the same way as visible light is refracted by lenses. These X-ray optical effects can be observed at small scattering angles of few minutes of arc as the refractive index n of X-rays is nearly unity (n = 1 - 10-6). Due to the short X-ray wavelength of about 0.1 nm the technique determines the amount of inner surfaces and interfaces of nanometer dimensions. The technique is expected to solve many problems in understanding the meaning of micro and sub micro structures in materials science. With the results of the CT investigation, some questions could be clarified for a better understanding of fatigue failure mechanisms under cyclic loading conditions. The specimens for the test programme have been provided by MTU Aero Engines. They consist of a titanium matrix (Ti6242) reinforced by SiC fibres (SCS6). The investigations have been performed at the materials research station of BAM (BAMline) at the Synchrotron Facility BESSY in Berlin, Germany
The implementation of a version of the Rutherford Laboratory's magnetostatic computer code GFUN3D on the CDC 7600 at the National Magnetic Fusion Energy Computer Center is reported. A new iteration technique that greatly increases the probability of convergence and reduces computation time by about 30% for calculations with nonlinear, ferromagnetic materials is included. The use of GFUN3D on the NMFE network is discussed, and suggestions for future work are presented. Appendix A consists of revisions to the GFUN3D User Guide (published by Rutherford Laboratory( that are necessary to use this version. Appendix B contains input and output for some sample calculations. Appendix C is a detailed discussion of the old and new iteration techniques
Auto-masked 2D/3D image registration and its validation with clinical cone-beam computed tomography
Image-guided alignment procedures in radiotherapy aim at minimizing discrepancies between the planned and the real patient setup. For that purpose, we developed a 2D/3D approach which rigidly registers a computed tomography (CT) with two x-rays by maximizing the agreement in pixel intensity between the x-rays and the corresponding reconstructed radiographs from the CT. Moreover, the algorithm selects regions of interest (masks) in the x-rays based on 3D segmentations from the pre-planning stage. For validation, orthogonal x-ray pairs from different viewing directions of 80 pelvic cone-beam CT (CBCT) raw data sets were used. The 2D/3D results were compared to corresponding standard 3D/3D CBCT-to-CT alignments. Outcome over 8400 2D/3D experiments showed that parametric errors in root mean square were <0.18° (rotations) and <0.73 mm (translations), respectively, using rank correlation as intensity metric. This corresponds to a mean target registration error, related to the voxels of the lesser pelvis, of <2 mm in 94.1% of the cases. From the results we conclude that 2D/3D registration based on sequentially acquired orthogonal x-rays of the pelvis is a viable alternative to CBCT-based approaches if rigid alignment on bony anatomy is sufficient, no volumetric intra-interventional data set is required and the expected error range fits the individual treatment prescription. (paper)
Madura, Thomas I; Gull, Theodore R; Kruip, Chael J H; Paardekooper, Jan-Pieter
2015-01-01
We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (>120 M_Sun), highly eccentric (e ~ 0.9) binary star system Eta Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF journal publication and the benefits of using 3D visualization and 3D printing as tools to analyze data from multidimensional numerical simulations. Using a consumer-grade 3D printer (MakerBot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics (SPH) simulations of Eta Carinae's inner (r ~ 110 au) wind-wind collision interface at multiple orbital phases. The 3D prints and visualizations reveal important, previously unknown 'finger-like' structures at orbital phases shortly after periastron (phi ~ 1.045) that protrude radially outward from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. thin-shell, Rayleigh-Taylor) that arise a...
Computation of neutron fluxes in clusters of fuel pins arranged in hexagonal assemblies (2D and 3D)
For computations of fluxes, we have used Carvik's method of collision probabilities. This method requires tracking algorithms. An algorithm to compute tracks (in 2D and 3D) has been developed for seven hexagonal geometries with cluster of fuel pins. This has been implemented in the NXT module of the code DRAGON. The flux distribution in cluster of pins has been computed by using this code. For testing the results, they are compared when possible with the EXCELT module of the code DRAGON. Tracks are plotted in the NXT module by using MATLAB, these plots are also presented here. Results are presented with increasing number of lines to show the convergence of these results. We have numerically computed volumes, surface areas and the percentage errors in these computations. These results show that 2D results converge faster than 3D results. The accuracy on the computation of fluxes up to second decimal is achieved with fewer lines. (authors)
Zhang, Luojiang; Hui, Kwun Nam; San Hui, Kwan; Lee, Haiwon
2016-06-01
The synthesis of layered double hydroxide (LDH) as electroactive material has been well reported; however, fabricating an LDH electrode with excellent electrochemical performance at high current density remains a challenge. In this paper, we report a 3D hierarchical porous flower-like NiAl-LDH grown on nickel foam (NF) through a liquid-phase deposition method as a high-performance binder-free electrode for energy storage. With large ion-accessible surface area as well as efficient electron and ion transport pathways, the prepared LDH-NF electrode achieves high specific capacity (1250 C g-1 at 2 A g-1 and 401 C g-1 at 50 A g-1) after 5000 cycles of activation at 20 A g-1 and high cycling stability (76.7% retention after another 5000 cycles at 50 A g-1), which is higher than those of most previously reported NiAl-LDH-based materials. Moreover, a hybrid supercapacitor with LDH-NF as the positive electrode and porous graphene nanosheet coated on NF (GNS-NF) as the negative electrode, delivers high energy density (30.2 Wh kg-1 at a power density of 800 W kg-1) and long cycle life, which outperforms the other devices reported in the literature. This study shows that the prepared LDH-NF electrode offers great potential in energy storage device applications.
We developed a computer-aided interactive surgical simulation system for craniofacial anomalies based on three-dimensional (3-D) surface reconstruction CT imaging. This system has four functions: 1) 3-D surface reconstruction display with an accelerated projection method; 2) Surgical simulation to cut, move, rotate, and reverse bone-blocks over the reference 3-D image on the CRT screen; 3) 3-D display of the simulated image in arbitrary views; and 4) Prediction of postoperative skin surface features displayed as 3-D images in arbitrary views. Retrospective surgical simulation has been performed on three patients who underwent the fronto-orbital advancement procedures for brachycephaly and two who underwent the reconstructive procedure for scaphocephaly. The predicted configurations of the cranium and skin surface were well simulated when compared to the postoperative images in 3-D arbitrary views. In practical use, this software might be used for an on-line system connected to a large scale general-purpose computer. (author)
A decentralized hierarchical computer system for digital reactor control
In this paper a decentralized hierarchical informational system (HIS) is presented which has been developed for monitoring and control of the Rossendorf Research Reactor RFR, but which may also be considered to be the prototype of a digital automation system to be used in power stations. The following functions are integrated in the HIS: process monitoring, on-line disturbance analysis, process control, and use of a specialized industrial robot for control of charging and discharging of the materials to be irradiated. The AS is realized on the basis of a process computer system. It includes the computer K 1630 and the intelligent process terminals ursadat 5000 connected by a fast serial interface. (author)
Kim, Jungkwun; Yoon, Yong-Kyu; Allen, Mark G.
2016-03-01
This paper presents a computer-numerical-controlled ultraviolet light-emitting diode (CNC UV-LED) lithography scheme for three-dimensional (3D) microfabrication. The CNC lithography scheme utilizes sequential multi-angled UV light exposures along with a synchronized switchable UV light source to create arbitrary 3D light traces, which are transferred into the photosensitive resist. The system comprises a switchable, movable UV-LED array as a light source, a motorized tilt-rotational sample holder, and a computer-control unit. System operation is such that the tilt-rotational sample holder moves in a pre-programmed routine, and the UV-LED is illuminated only at desired positions of the sample holder during the desired time period, enabling the formation of complex 3D microstructures. This facilitates easy fabrication of complex 3D structures, which otherwise would have required multiple manual exposure steps as in the previous multidirectional 3D UV lithography approach. Since it is batch processed, processing time is far less than that of the 3D printing approach at the expense of some reduction in the degree of achievable 3D structure complexity. In order to produce uniform light intensity from the arrayed LED light source, the UV-LED array stage has been kept rotating during exposure. UV-LED 3D fabrication capability was demonstrated through a plurality of complex structures such as V-shaped micropillars, micropanels, a micro-‘hi’ structure, a micro-‘cat’s claw,’ a micro-‘horn,’ a micro-‘calla lily,’ a micro-‘cowboy’s hat,’ and a micro-‘table napkin’ array.
This paper presents a computer-numerical-controlled ultraviolet light-emitting diode (CNC UV-LED) lithography scheme for three-dimensional (3D) microfabrication. The CNC lithography scheme utilizes sequential multi-angled UV light exposures along with a synchronized switchable UV light source to create arbitrary 3D light traces, which are transferred into the photosensitive resist. The system comprises a switchable, movable UV-LED array as a light source, a motorized tilt-rotational sample holder, and a computer-control unit. System operation is such that the tilt-rotational sample holder moves in a pre-programmed routine, and the UV-LED is illuminated only at desired positions of the sample holder during the desired time period, enabling the formation of complex 3D microstructures. This facilitates easy fabrication of complex 3D structures, which otherwise would have required multiple manual exposure steps as in the previous multidirectional 3D UV lithography approach. Since it is batch processed, processing time is far less than that of the 3D printing approach at the expense of some reduction in the degree of achievable 3D structure complexity. In order to produce uniform light intensity from the arrayed LED light source, the UV-LED array stage has been kept rotating during exposure. UV-LED 3D fabrication capability was demonstrated through a plurality of complex structures such as V-shaped micropillars, micropanels, a micro-‘hi’ structure, a micro-‘cat’s claw,’ a micro-‘horn,’ a micro-‘calla lily,’ a micro-‘cowboy’s hat,’ and a micro-‘table napkin’ array. (paper)
A new cone-beam computed tomography system for dental applications with innovative 3D software
Pasini, Alessandro; Bianconi, D.; Rossi, A. [University of Bologna, Department of Physics, Bologna (Italy); NECTAR Imaging srl Imola (Italy); Casali, F. [University of Bologna, Department of Physics, Bologna (Italy); Bontempi, M. [CEFLA Dental Group Imola (Italy)
2007-02-15
Objective Cone beam computed tomography (CBCT) is an important image technique for oral surgery (dentoalveolar surgery and dental implantology) and maxillofacial applications. This technique requires compact sized scanners with a relatively low radiation dosage, which makes them suitable for imaging of the craniofacial region. This article aims to present the concept and the preliminary findings obtained with the prototype of a new CBCT scanner with dedicated 3D software, specifically designed for dental imaging. Methods The prototype implements an X-ray tube with a nominal focal spot of 0.5 mm operating at 70-100 kVp and 1-4 mA. The detector is a 6 in. image intensifier coupled with a digital CCD camera. Dosimetry was performed on a RANDO anthropomorphic phantom using Beryllium Oxide thermo-luminescent dosimeters positioned in the phantom in the following site: eyes, thyroid, skin (lips, cheeks, back of the neck), brain, mandible, maxilla and parotid glands. Doses were measured using four configurations, changing the field-of-view (4'' and 6'') and acquisition time (10 and 20 s) of the CBCT. Acquisitions were performed with different parameters regarding the x-ray tube, pixel size and acquisition geometries to evaluate image quality in relation to modulation transfer function (MTF), noise and geometric accuracy. Results The prototype was able to acquire a complete maxillofacial scan in 10-15 s. The CT reconstruction algorithm delivered images that were judged to have high quality, allowing for precise volume rendering. The radiation dose was determined to be 1-1.5 times that of the dose applied during conventional dental panoramic studies. Conclusion Preliminary studies using the CBCT prototype indicate that this device provides images with acceptable diagnostic content at a relatively low radiation dosage, if compared to systems currently available on the market. (orig.)
Ziegle, Jens; Müller, Bernhard H.; Neumann, Bernd; Hoeschen, Christoph
2016-03-01
A new 3D breast computed tomography (CT) system is under development enabling imaging of microcalcifications in a fully uncompressed breast including posterior chest wall tissue. The system setup uses a steered electron beam impinging on small tungsten targets surrounding the breast to emit X-rays. A realization of the corresponding detector concept is presented in this work and it is modeled through Monte Carlo simulations in order to quantify first characteristics of transmission and secondary photons. The modeled system comprises a vertical alignment of linear detectors hold by a case that also hosts the breast. Detectors are separated by gaps to allow the passage of X-rays towards the breast volume. The detectors located directly on the opposite side of the gaps detect incident X-rays. Mechanically moving parts in an imaging system increase the duration of image acquisition and thus can cause motion artifacts. So, a major advantage of the presented system design is the combination of the fixed detectors and the fast steering electron beam which enable a greatly reduced scan time. Thereby potential motion artifacts are reduced so that the visualization of small structures such as microcalcifications is improved. The result of the simulation of a single projection shows high attenuation by parts of the detector electronics causing low count levels at the opposing detectors which would require a flat field correction, but it also shows a secondary to transmission ratio of all counted X-rays of less than 1 percent. Additionally, a single slice with details of various sizes was reconstructed using filtered backprojection. The smallest detail which was still visible in the reconstructed image has a size of 0.2mm.
A new cone-beam computed tomography system for dental applications with innovative 3D software
Objective Cone beam computed tomography (CBCT) is an important image technique for oral surgery (dentoalveolar surgery and dental implantology) and maxillofacial applications. This technique requires compact sized scanners with a relatively low radiation dosage, which makes them suitable for imaging of the craniofacial region. This article aims to present the concept and the preliminary findings obtained with the prototype of a new CBCT scanner with dedicated 3D software, specifically designed for dental imaging. Methods The prototype implements an X-ray tube with a nominal focal spot of 0.5 mm operating at 70-100 kVp and 1-4 mA. The detector is a 6 in. image intensifier coupled with a digital CCD camera. Dosimetry was performed on a RANDO anthropomorphic phantom using Beryllium Oxide thermo-luminescent dosimeters positioned in the phantom in the following site: eyes, thyroid, skin (lips, cheeks, back of the neck), brain, mandible, maxilla and parotid glands. Doses were measured using four configurations, changing the field-of-view (4'' and 6'') and acquisition time (10 and 20 s) of the CBCT. Acquisitions were performed with different parameters regarding the x-ray tube, pixel size and acquisition geometries to evaluate image quality in relation to modulation transfer function (MTF), noise and geometric accuracy. Results The prototype was able to acquire a complete maxillofacial scan in 10-15 s. The CT reconstruction algorithm delivered images that were judged to have high quality, allowing for precise volume rendering. The radiation dose was determined to be 1-1.5 times that of the dose applied during conventional dental panoramic studies. Conclusion Preliminary studies using the CBCT prototype indicate that this device provides images with acceptable diagnostic content at a relatively low radiation dosage, if compared to systems currently available on the market. (orig.)
A Pipeline for 3D Multimodality Image Integration and Computer-assisted Planning in Epilepsy Surgery
Nowell, Mark; Rodionov, Roman; Zombori, Gergely; Sparks, Rachel; Rizzi, Michele; Ourselin, Sebastien; Miserocchi, Anna; McEvoy, Andrew; Duncan, John
2016-01-01
Epilepsy surgery is challenging and the use of 3D multimodality image integration (3DMMI) to aid presurgical planning is well-established. Multimodality image integration can be technically demanding, and is underutilised in clinical practice. We have developed a single software platform for image integration, 3D visualization and surgical planning. Here, our pipeline is described in step-by-step fashion, starting with image acquisition, proceeding through image co-registration, manual segmen...
Bristeau, Marie-Odile; Glowinski, Roland; Périaux, Jacques; Rossi, Tuomo
1999-01-01
We consider the scattering problem for 3-D electromagnetic harmonic waves. The time-domain Maxwell's equations are solved and Exact Controllability methods improve the convergence of the solutions to the time-periodic ones for nonconvex obstacles. A least-squares formulation solved by a preconditioned conjugate gradient is introduced. The discretization is achieved in time by a centered finite difference scheme and in space by Lagrange finite elements. Numerical results for 3-D nonconvex scat...
Bartels, Robert E.
2012-01-01
This paper presents the implementation of gust modeling capability in the CFD code FUN3D. The gust capability is verified by computing the response of an airfoil to a sharp edged gust. This result is compared with the theoretical result. The present simulations will be compared with other CFD gust simulations. This paper also serves as a users manual for FUN3D gust analyses using a variety of gust profiles. Finally, the development of an Auto-Regressive Moving-Average (ARMA) reduced order gust model using a gust with a Gaussian profile in the FUN3D code is presented. ARMA simulated results of a sequence of one-minus-cosine gusts is shown to compare well with the same gust profile computed with FUN3D. Proper Orthogonal Decomposition (POD) is combined with the ARMA modeling technique to predict the time varying pressure coefficient increment distribution due to a novel gust profile. The aeroelastic response of a pitch/plunge airfoil to a gust environment is computed with a reduced order model, and compared with a direct simulation of the system in the FUN3D code. The two results are found to agree very well.
Rodríguez-Sánchez, Rafael; Martínez, José Luis; Cock, Jan De; Fernández-Escribano, Gerardo; Pieters, Bart; Sánchez, José L.; Claver, José M.; de Walle, Rik Van
2013-12-01
The H.264/AVC video coding standard introduces some improved tools in order to increase compression efficiency. Moreover, the multi-view extension of H.264/AVC, called H.264/MVC, adopts many of them. Among the new features, variable block-size motion estimation is one which contributes to high coding efficiency. Furthermore, it defines a different prediction structure that includes hierarchical bidirectional pictures, outperforming traditional Group of Pictures patterns in both scenarios: single-view and multi-view. However, these video coding techniques have high computational complexity. Several techniques have been proposed in the literature over the last few years which are aimed at accelerating the inter prediction process, but there are no works focusing on bidirectional prediction or hierarchical prediction. In this article, with the emergence of many-core processors or accelerators, a step forward is taken towards an implementation of an H.264/AVC and H.264/MVC inter prediction algorithm on a graphics processing unit. The results show a negligible rate distortion drop with a time reduction of up to 98% for the complete H.264/AVC encoder.
De Silva, R. T.; Pasbakhsh, Pooria; Goh, K. L.;
2014-01-01
A real-structure based 3-D micromechanical computational model of poly (lactic acid) nanocomposites reinforced by randomly oriented halloysite nanotubes (HNTs) was developed and compared with an idealized model (conventional model) and experimental results. The developed idealized model consists of...
Stull, Kyra E; Tise, Meredith L; Ali, Zabiullah; Fowler, David R
2014-05-01
Forensic pathologists commonly use computed tomography (CT) images to assist in determining the cause and manner of death as well as for mass disaster operations. Even though the design of the CT machine does not inherently produce distortion, most techniques within anthropology rely on metric variables, thus concern exists regarding the accuracy of CT images reflecting an object's true dimensions. Numerous researchers have attempted to validate the use of CT images, however the comparisons have only been conducted on limited elements and/or comparisons were between measurements taken from a dry element and measurements taken from the 3D-CT image of the same dry element. A full-body CT scan was performed prior to autopsy at the Office of the Chief Medical Examiner for the State of Maryland. Following autopsy, the remains were processed to remove all soft tissues and the skeletal elements were subject to an additional CT scan. Percent differences and Bland-Altman plots were used to assess the accuracy between osteometric variables obtained from the dry skeletal elements and from CT images with and without soft tissues. An additional seven crania were scanned, measured by three observers, and the reliability was evaluated by technical error of measurement (TEM) and relative technical error of measurement (%TEM). Average percent differences between the measurements obtained from the three data sources ranged from 1.4% to 2.9%. Bland-Altman plots illustrated the two sets of measurements were generally within 2mm for each comparison between data sources. Intra-observer TEM and %TEM for three observers and all craniometric variables ranged between 0.46mm and 0.77mm and 0.56% and 1.06%, respectively. The three-way inter-observer TEM and %TEM for craniometric variables was 2.6mm and 2.26%, respectively. Variables that yielded high error rates were orbital height, orbital breadth, inter-orbital breadth and parietal chord. Overall, minimal differences were found among the
Effective Permeability of Fractured Rocks by Analytical Methods: A 3D Computational Study
Sævik, P. N.; Berre, I.; Jakobsen, M.; Lien, M.
2013-12-01
Analytical upscaling methods have been proposed in the literature to predict the effective hydraulic permeability of a fractured rock from its micro-scale parameters (fracture aperture, fracture orientation, fracture content, etc.). In this presentation, we put special emphasis on three effective medium methods (the symmetric and asymmetric self-consistent methods, and the differential method), and evaluate their accuracy for a wide range of parameter values. The analytical predictions are computed using our recently developed effective medium formulations, which are specifically adapted for fractured media. Compared to previous formulations, the new expressions have improved numerical stability properties, and require fewer input parameters. To assess their accuracy, the analytical predictions have been compared with 3D finite element simulations. Specifically, we generated realizations of several different fracture geometries, each consisting of 102 fractures within a unit cube. We applied unit potential difference on two opposing sides, and no-flux conditions on the remaining sides. A commercial finite-element solver was used to calculate the mean flux, from which the effective conductivity was found. This process was repeated for fracture densities up to ɛ = 1.0. Also, a wide range of fracture permeabilities was considered, from completely blocking to infinitely permeable fractures. The results were used to determine the range of applicability for each analytical method, which excels in different regions of the parameter space. For blocking fractures, the differential method is very accurate throughout the investigated parameter range. The symmetric self-consistent method also agrees well with the numerical results on sealed fractures, while the asymmetric self-consistent method is more unreliable. For permeable fractures, the performance of the methods depends on the dimensionless quantity λ = (Kfrac a)/(r Kmat ), describing the contrast between fracture and
KNOW-BLADE task-3.3 report: Rotor blade computations with 3D vortex generators
Johansen, J.; Sørensen, Niels N.; Reck, M.; Hansen, M.O.L.; Stuermer, A.; Ramboer, J.; Hirsch, C.; Ekaterinaris, J.; Voutsinas, S.; Perivolaris, Y.
2005-01-01
successfully modelled vortex generators in 3D, which eventually generates vortices and mixes the boundary layer.A large effort has been on generating the numerical meshes since this is a relatively complex configuration and a large variation of length and time scales is present. Even though the quantitative...... agreement with measurements is not acceptable the effortspend in the present project indicate that it is possible to investigate the effect of vortex generators on wind turbine blades using 3D Navier-Stokes solvers. Much further work within independence of mesh resolution and time step as well as...
Jeffcoate, Penelope
2013-01-01
The near-field depth-varying velocities and resulting bed stresses downstream from a tidal barrage have not previously been studied. The flow through and downstream of a row of seven open draft tubes in a barrage has been investigated through laboratory experiment in a wide flume, 3-D RANS CFD simulation and 2-D depth-averaged computation. When there is no turbine representation and hence negligible swirl in the draft tubes, agreement between the experiments and 3-D modelling is shown to be g...
Computational Graph Model for 3D Cells Tracking in Zebra Fish Datasets
Zhang, Lelin; Xiong, Hongkai; Zhao, Yang; Zhang, Kai; Zhou, Xiaobo
2007-11-01
This paper leads to a novel technique for tracking and identification of zebra-fish cells in 3D image sequences, extending graph-based multi-objects tracking algorithm to 3D applications. As raised in previous work of 2D graph-based method, separated cells are modeled as vertices that connected by edges. Then the tracking work is simplified to that of vertices matching between graphs generated from consecutive frames. Graph-based tracking is composed of three steps: graph generation, initial source vertices selection and graph saturation. To satisfy demands in this work separated cell records are segmented from original datasets using 3D level-set algorithms. Besides, advancements are achieved in each of the step including graph regulations, multi restrictions on source vertices and enhanced flow quantifications. Those strategies make a good compensation for graph-based multi-objects tracking method in 2D space. Experiments are carried out in 3D datasets sampled from zebra fish, results of which shows that this enhanced method could be potentially applied to tracking of objects with diverse features.
Rasmussen, Henrik Koblitz
2000-01-01
(polymeric melts) and polymeric solutions. Secondly, the 3D-LIM has also been applied to calculate the inflation of a thick sheet of a polymer melt into an elliptic cylinder. These problems all include free surfaces. As the governing equations are solved for the particle positions, the motion of surfaces can...
Grid-Adapted FUN3D Computations for the Second High Lift Prediction Workshop
Lee-Rausch, E. M.; Rumsey, C. L.; Park, M. A.
2014-01-01
Contributions of the unstructured Reynolds-averaged Navier-Stokes code FUN3D to the 2nd AIAA CFD High Lift Prediction Workshop are described, and detailed comparisons are made with experimental data. Using workshop-supplied grids, results for the clean wing configuration are compared with results from the structured code CFL3D Using the same turbulence model, both codes compare reasonably well in terms of total forces and moments, and the maximum lift is similarly over-predicted for both codes compared to experiment. By including more representative geometry features such as slat and flap brackets and slat pressure tube bundles, FUN3D captures the general effects of the Reynolds number variation, but under-predicts maximum lift on workshop-supplied grids in comparison with the experimental data, due to excessive separation. However, when output-based, off-body grid adaptation in FUN3D is employed, results improve considerably. In particular, when the geometry includes both brackets and the pressure tube bundles, grid adaptation results in a more accurate prediction of lift near stall in comparison with the wind-tunnel data. Furthermore, a rotation-corrected turbulence model shows improved pressure predictions on the outboard span when using adapted grids.
Madura, Thomas; Gull, Theodore R.; Clementel, Nicola; Paardekooper, Jan-Pieter; Kruip, Chael; Corcoran, Michael F.; Hamaguchi, Kenji; Teodoro, Mairan
2015-01-01
We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (>120 MSun), highly eccentric (e ~ 0.9) binary Eta Carinae. Using a consumer-grade 3D printer (Makerbot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics simulations of Eta Carinae's inner (r ~110 AU) wind-wind collision interface at multiple orbital phases. These 3D prints reveal important, previously unknown 'finger-like' structures at orbital phases shortly after periastron (φ ~1.045) that protrude radially outward from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. Rayleigh-Taylor) that arise at the interface between the radiatively-cooled layer of dense post-shock primary-star wind and the hot, adiabatic post-shock companion-star wind. The success of our work and easy identification of previously unknown physical features highlight the important role 3D printing can play in the visualization and understanding of complex 3D time-dependent numerical simulations of astrophysical phenomena.
Vazquez Bustos, Jesus; Segura Ozuna, Victor Octavio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)
2012-06-22
The evolution and incorporation of new hardware technologies, as well as recent advances in computer systems have enabled the development of applications of computer aided design of most complete scope, such as those used for the design of industrial process plants. This article describes a software system developed to complement the capabilities of one of these systems for the design of process plants. A 3D electronic model is generated through the user interface of the design system that at the same time gives the user the ability to generate, publish, review and control the engineering document that are generated during the entire life cycle of a marine oil platform, a very particular type of industrial process plant. This way, the user obtains not only a tool for the design of an industrial plant, but also a system for managing information and engineering documents that are developed. This allows the user to do a more efficient job by putting at his disposal and in the same system, all documents and information required to perform his duty. [Spanish] La evolucion e incorporacion de nuevas tecnologias de hardware, junto con los avances recientes en sistemas de computo ha permitido el desarrollo de aplicaciones de interesante diseno de computo de mayor alcance, tales como los que se emplean en las plantas de procesos industriales. Este articulo describe un sistema de software desarrollado para complementar las capacidades de uno de estos sistemas para el diseno de proceso. Un modelo electronico se genera por medio de la interfaz de usuario del sistema de diseno, que al mismo tiempo da al usuario la capacidad para crear, publicar, revisar y controlar los documentos de ingenieria que se producen durante el ciclo de vida completo de una plataforma marina petrolera, un tipo muy particular de planta de proceso industrial. De este modo, el usuario no solo obtiene una herramienta para el diseno de una planta industrial, sino tambien un sistema para manejar informacion y
The use of three dimensional(3D) computer-aided design and drafting(CADD) models, and the associated information technology and databases, in the engineering and construction phases of large projects is well established and yielding significant improvements in project cost, schedule and quality. The information contained in these models can also be extremely valuable to operating plants, particularly when the visual and spatial information contained in the 3D models is interfaced to other plant information databases. Indeed many plant owners and operators in the process and power industries are already using this technology to assist with such activities as plant configuration management, staff training, work planning and radiation protection. This paper will explore the application of 3D models and the associated databases in an operating plant environment and describe the resulting operational benefits and cost reduction benefits. Several industrial experience case studies will be presented along with suggestions for further future applications. (author). 4 refs., 1 tab., 8 figs
We are developing a computer-aided diagnosis (CAD) system to classify malignant and benign lung nodules found on CT scans. A fully automated system was designed to segment the nodule from its surrounding structured background in a local volume of interest (VOI) and to extract image features for classification. Image segmentation was performed with a three-dimensional (3D) active contour (AC) method. A data set of 96 lung nodules (44 malignant, 52 benign) from 58 patients was used in this study. The 3D AC model is based on two-dimensional AC with the addition of three new energy components to take advantage of 3D information: (1) 3D gradient, which guides the active contour to seek the object surface (2) 3D curvature, which imposes a smoothness constraint in the z direction, and (3) mask energy, which penalizes contours that grow beyond the pleura or thoracic wall. The search for the best energy weights in the 3D AC model was guided by a simplex optimization method. Morphological and gray-level features were extracted from the segmented nodule. The rubber band straightening transform (RBST) was applied to the shell of voxels surrounding the nodule. Texture features based on run-length statistics were extracted from the RBST image. A linear discriminant analysis classifier with stepwise feature selection was designed using a second simplex optimization to select the most effective features. Leave-one-case-out resampling was used to train and test the CAD system. The system achieved a test area under the receiver operating characteristic curve (Az) of 0.83±0.04. Our preliminary results indicate that use of the 3D AC model and the 3D texture features surrounding the nodule is a promising approach to the segmentation and classification of lung nodules with CAD. The segmentation performance of the 3D AC model trained with our data set was evaluated with 23 nodules available in the Lung Image Database Consortium (LIDC). The lung nodule volumes segmented by the 3D AC
Li, Yunfeng; Pizlo, Zygmunt; Steinman, Robert M
2009-05-01
Human beings perceive 3D shapes veridically, but the underlying mechanisms remain unknown. The problem of producing veridical shape percepts is computationally difficult because the 3D shapes have to be recovered from 2D retinal images. This paper describes a new model, based on a regularization approach, that does this very well. It uses a new simplicity principle composed of four shape constraints: viz., symmetry, planarity, maximum compactness and minimum surface. Maximum compactness and minimum surface have never been used before. The model was tested with random symmetrical polyhedra. It recovered their 3D shapes from a single randomly-chosen 2D image. Neither learning, nor depth perception, was required. The effectiveness of the maximum compactness and the minimum surface constraints were measured by how well the aspect ratio of the 3D shapes was recovered. These constraints were effective; they recovered the aspect ratio of the 3D shapes very well. Aspect ratios recovered by the model were compared to aspect ratios adjusted by four human observers. They also adjusted aspect ratios very well. In those rare cases, in which the human observers showed large errors in adjusted aspect ratios, their errors were very similar to the errors made by the model. PMID:18621410
Identification and classification in le fort type fractures by using 2D and 3D computed tomography
CHEN We-jian; YANG Yun-jun; FANG Yi-ming; XU Fang-hong; ZHANG Lin; CAO Guo-quan
2006-01-01
Objective:To evaluate the usefulness of twodimensional (2D) and three-dimensional (3D) computed tomography (CT) in the identification and classification of Le Fort type fractures.Methods: Sixty-two patients with different types of Le Fort fractures underwent CT scanning and 3D-CT reconstruction. The data were analyzed by multiplanar reconstruction (MPR), surface shaded display (SSD) and volume rendering (VR) respectively.Results: The patients with Le Fort Ⅰ , Le Fort Ⅱfracture and Le Fort Ⅲ fracture accounted for 16.1%,14.5 % and 12.9 % respectively. The compound fractures were the most common type and accounted for 56.5 % ( n =35, 18 cases with Le Fort Ⅰ + Ⅱ fracture, 10 cases with Le Fort Ⅱ + Ⅲ fracture and 7 cases with Le Fort Ⅰ + Ⅱ + Ⅲfracture). Fifty-five cases coexisted with other fractures in maxillofacial region. 2D-CT could be used to define the tiny fractures and the deep-structure fractures more accurately compared with 3D-CT, but the real impression of Le Fort type fractures could not be correctly evaluated on 2D-CT.3D-CT could clearly demonstrate the whole shape of Le Fort type fractures and identify the classification of Le Fort fractures.Conclusions: 3D-CT is the best imaging method for the diagnosis of Le Fort type fractures and can provide valuable information of space relationship, especially for the design of treatment plan before operation.
Jung, Jin Woo; Lee, Jung-Seob; Cho, Dong-Woo
2016-02-01
Recently, much attention has focused on replacement or/and enhancement of biological tissues via the use of cell-laden hydrogel scaffolds with an architecture that mimics the tissue matrix, and with the desired three-dimensional (3D) external geometry. However, mimicking the heterogeneous tissues that most organs and tissues are formed of is challenging. Although multiple-head 3D printing systems have been proposed for fabricating heterogeneous cell-laden hydrogel scaffolds, to date only the simple exterior form has been realized. Here we describe a computer-aided design and manufacturing (CAD/CAM) system for this application. We aim to develop an algorithm to enable easy, intuitive design and fabrication of a heterogeneous cell-laden hydrogel scaffolds with a free-form 3D geometry. The printing paths of the scaffold are automatically generated from the 3D CAD model, and the scaffold is then printed by dispensing four materials; i.e., a frame, two kinds of cell-laden hydrogel and a support. We demonstrated printing of heterogeneous tissue models formed of hydrogel scaffolds using this approach, including the outer ear, kidney and tooth tissue. These results indicate that this approach is particularly promising for tissue engineering and 3D printing applications to regenerate heterogeneous organs and tissues with tailored geometries to treat specific defects or injuries.
Tesařová, M.; Zikmund, T.; Kaucká, M.; Adameyko, I.; Jaroš, J.; Paloušek, D.; Škaroupka, D.; Kaiser, J.
2016-03-01
Imaging of increasingly complex cartilage in vertebrate embryos is one of the key tasks of developmental biology. This is especially important to study shape-organizing processes during initial skeletal formation and growth. Advanced imaging techniques that are reflecting biological needs give a powerful impulse to push the boundaries of biological visualization. Recently, techniques for contrasting tissues and organs have improved considerably, extending traditional 2D imaging approaches to 3D . X-ray micro computed tomography (μCT), which allows 3D imaging of biological objects including their internal structures with a resolution in the micrometer range, in combination with contrasting techniques seems to be the most suitable approach for non-destructive imaging of embryonic developing cartilage. Despite there are many software-based ways for visualization of 3D data sets, having a real solid model of the studied object might give novel opportunities to fully understand the shape-organizing processes in the developing body. In this feasibility study we demonstrated the full procedure of creating a real 3D object of mouse embryo nasal capsule, i.e. the staining, the μCT scanning combined by the advanced data processing and the 3D printing.
M. Schmitt
2015-12-01
Full Text Available Recent years have seen a growing interest in the characterization of the pore morphologies of reservoir rocks and how the spatial organization of pore traits affects the macro behaviour of rock-fluid systems. With the availability of 3-D high-resolution imaging (e.g. μ-CT, the detailed quantification of particle shapes has been facilitated by progress in computer science. Here, we show how the shapes of irregular rock particles (pores can be classified and quantified based on binary 3-D images. The methodology requires the measurement of basic 3-D particle descriptors and a shape classification that involves the similarity of artificial objects, which is based on main pore network detachments and 3-D sample sizes. The results were validated for three sandstones (S1, S2 and S3 from distinct reservoirs, and most of the pore shapes were found to be plate- and cube-like. Furthermore, this study generalizes a practical way to correlate specific particle shapes, such as rods, blades, cuboids, plates and cubes, to characterize asymmetric particles of any material type with 3-D image analysis.
Imaging of increasingly complex cartilage in vertebrate embryos is one of the key tasks of developmental biology. This is especially important to study shape-organizing processes during initial skeletal formation and growth. Advanced imaging techniques that are reflecting biological needs give a powerful impulse to push the boundaries of biological visualization. Recently, techniques for contrasting tissues and organs have improved considerably, extending traditional 2D imaging approaches to 3D . X-ray micro computed tomography (μCT), which allows 3D imaging of biological objects including their internal structures with a resolution in the micrometer range, in combination with contrasting techniques seems to be the most suitable approach for non-destructive imaging of embryonic developing cartilage. Despite there are many software-based ways for visualization of 3D data sets, having a real solid model of the studied object might give novel opportunities to fully understand the shape-organizing processes in the developing body. In this feasibility study we demonstrated the full procedure of creating a real 3D object of mouse embryo nasal capsule, i.e. the staining, the μCT scanning combined by the advanced data processing and the 3D printing
Mozafar Shokri Rad
2015-01-01
Full Text Available Auxetic materials exhibit a unique characteristic due to the altered microstructure. Different structures have been used to model these materials. This paper treats a development of finite element model and theoretical formulation of 3D star honeycomb structure of these materials. Various shape parameters of the structural cell were evaluated with respect to the basic mechanical properties of the cell. Finite element and analytical approach for various geometrical parameters were numerically used to formulate the characteristics of the material. The study aims at quantifying mechanical properties for any domain in which auxetic material is of interest for variations in geometrical parameters. It is evident that mechanical properties of the material could be controlled by changing the base wall angle of the configuration. The primary outcome of the study is a design guideline for the use of 3D star honeycomb auxetic cellular structure in structural applications.
Reliability of clinically relevant 3D foot bone angles from quantitative computed tomography
Gutekunst, David J; Liu, Lu; Ju, Tao; Prior, Fred W.; Sinacore, David R
2013-01-01
Background Surgical treatment and clinical management of foot pathology requires accurate, reliable assessment of foot deformities. Foot and ankle deformities are multi-planar and therefore difficult to quantify by standard radiographs. Three-dimensional (3D) imaging modalities have been used to define bone orientations using inertial axes based on bone shape, but these inertial axes can fail to mimic established bone angles used in orthopaedics and clinical biomechanics. To provide improved ...
KNOW-BLADE task-3.3 report. Rotor blade computations with 3D vortex generators
Johansen, J.; Soerensen, N.N.; Reck, M. (and others)
2005-01-01
The present report describes the work done in work package WP3.3: Aerodynamic Accessories in 3D in the EC project KNOW-BLADE. Vortex generators (VGs) are modelled in 3D Navier-Stokes solvers and applied on the flow around an airfoil and a wind turbine blade. Three test cases have been investigated. They are: 1) A non-rotating airfoil section with VGs. 2) A rotating airfoil section with VGs. 3) A non-rotating wind turbine blade with VGs. The airfoil section was the FFA-W3-241 airfoil, which has been measured in the VELUX wind tunnel with and without VGs placed at different chord wise positions. Three of the partners have modelled the airfoil section as a thin airfoil section with symmetry boundary conditions in the span wise direction to simulate an array of VGs. The wind turbine blade is the LM19.1 blade equipped with one pair of VGs placed at radius = 8.5 m. In general all partners have successfully modelled vortex generators in 3D, which eventually generates vortices and mixes the boundary layer. A large effort has been on generating the numerical meshes since this is a relatively complex configuration and a large variation of length and time scales is present. Even though the quantitative agreement with measurements is not acceptable the effort spend in the present project indicate that it is possible to investigate the effect of vortex generators on wind turbine blades using 3D Navier-Stokes solvers. Much further work within independence of mesh resolution and time step as well as turbulence modelling has to be carried out in future projects before parametric variations can be investigated. (au)
Nowell, Mark; Rodionov, Roman; Zombori, Gergely; Sparks, Rachel; Rizzi, Michele; Ourselin, Sebastien; Miserocchi, Anna; McEvoy, Andrew; Duncan, John
2016-01-01
Epilepsy surgery is challenging and the use of 3D multimodality image integration (3DMMI) to aid presurgical planning is well-established. Multimodality image integration can be technically demanding, and is underutilised in clinical practice. We have developed a single software platform for image integration, 3D visualization and surgical planning. Here, our pipeline is described in step-by-step fashion, starting with image acquisition, proceeding through image co-registration, manual segmentation, brain and vessel extraction, 3D visualization and manual planning of stereoEEG (SEEG) implantations. With dissemination of the software this pipeline can be reproduced in other centres, allowing other groups to benefit from 3DMMI. We also describe the use of an automated, multi-trajectory planner to generate stereoEEG implantation plans. Preliminary studies suggest this is a rapid, safe and efficacious adjunct for planning SEEG implantations. Finally, a simple solution for the export of plans and models to commercial neuronavigation systems for implementation of plans in the operating theater is described. This software is a valuable tool that can support clinical decision making throughout the epilepsy surgery pathway. PMID:27286266
A Pipeline for 3D Multimodality Image Integration and Computer-assisted Planning in Epilepsy Surgery
Nowell, Mark; Rodionov, Roman; Zombori, Gergely; Sparks, Rachel; Rizzi, Michele; Ourselin, Sebastien; Miserocchi, Anna; McEvoy, Andrew; Duncan, John
2016-01-01
Epilepsy surgery is challenging and the use of 3D multimodality image integration (3DMMI) to aid presurgical planning is well-established. Multimodality image integration can be technically demanding, and is underutilised in clinical practice. We have developed a single software platform for image integration, 3D visualization and surgical planning. Here, our pipeline is described in step-by-step fashion, starting with image acquisition, proceeding through image co-registration, manual segmentation, brain and vessel extraction, 3D visualization and manual planning of stereoEEG (SEEG) implantations. With dissemination of the software this pipeline can be reproduced in other centres, allowing other groups to benefit from 3DMMI. We also describe the use of an automated, multi-trajectory planner to generate stereoEEG implantation plans. Preliminary studies suggest this is a rapid, safe and efficacious adjunct for planning SEEG implantations. Finally, a simple solution for the export of plans and models to commercial neuronavigation systems for implementation of plans in the operating theater is described. This software is a valuable tool that can support clinical decision making throughout the epilepsy surgery pathway. PMID:27286266
Felician ALECU
2010-01-01
Full Text Available Many professionals and 3D artists consider Blender as being the best open source solution for 3D computer graphics. The main features are related to modeling, rendering, shading, imaging, compositing, animation, physics and particles and realtime 3D/game creation.
Interactive computer graphics displays for hierarchical data structures
An interactive computer graphical display program was developed as an aid to user visualization and manipulation of hierarchically structured data systems such as thesauri. In the present configuration, a thesaurus term and its primary and secondary conceptual neighbors are presented to the user in tree graph form on a CRT; the user then designates, via light pen or keyboard, any of the neighbors as the next term of interest and receives a new display centered on this term. By successive specification of broader, narrower, and related terms, the user can course rapidly through the thesaurus space and refine his search file. At any stage, he deals with a term-centered, conceptually meaningful picture of a localized portion of the thesaurus, and is freed from the artificial difficulties of handling the traditional alphabetized thesaurus. Intentional limitation of the associative range of each display frame, and the use of color, case, and interconnecting vectors to encode relationships among terms, enhance interpretability of the display. Facile movement through the term space, provided by interactive computation, allows the display to remain simple, and is an essential element of the system. 3 figures
Using the 2-D data provided by CT-Tomography and MRI-tomography of oral and maxillofacial diseases (cyst, benign tumor, primary tumor and regional lymphnodes of malignant tumor), 3-D images were reconstructed and spatial analysis was attempted. We report the general concepts. The hardware used consisted of the Hewlett-Packard HP-9000/300, which utilizes a 16-bit CPU. A digitizer was used to construct 3-D images from serial CT-tomography and MRI-tomography images. Output was displayed on a color monitor and photographs. The 3 cases on which we used this technique included a 19-year-old male with plunging ranula, a 50-year-old male with maxillary pleomorphic adenoma, and a 58-year-old male with squamous cell carcinoma of the maxillary sinus (T3N3M0). As 3-D reconstruction can be done in any arbitrary direction or cross section, it is possible to spatially determine the position of the disease inside the body, its progression, and its relationship with adjacent organs. Through image analysis, it is possible to better understand the volume and surface area of the disease. 3-D image reconstruction is an effective tool in the determination of diagnosis, therapeutic guidelines, and surgical indications, as well as effectiveness of treatment. (author)
Lemaitre, Sophie; Choi, Daniel; Karamian, Philippe
2015-01-01
In this paper we study the thermal effective behaviour for 3D multiphase composite material consisting of three isotropic phases which are the matrix, the inclusions and the coating media. For this purpose we use an accelerated FFT-based scheme initially proposed in Eyre and Milton (1999) to evaluate the thermal conductivity tensor. Matrix and spherical inclusions media are polymers with similar properties whereas the coating medium is metallic hence better conducting. Thus, the contrast between the coating and the others media is very large. For our study, we use RVEs (Representative volume elements) generated by RSA (Random Sequential Adsorption) method developed in our previous works, then, we compute effective thermal properties using an FFT-based homogenization technique validated by comparison with the direct finite elements method. We study the thermal behaviour of the 3D-multiphase composite material and we show what features should be taken into account to make the computational approach efficient.
Numerical computation of critical properties and atomic basins from 3D grid electron densities
Katan, C; Lecomte, C; Guezo, M; Oison, V; Souhassou, M
2003-01-01
InteGriTy is a software package that performs topological analysis following AIM approach on electron densities given on 3D grids. Use of tricubic interpolation is made to get the density, its gradient and hessian matrix at any required position. Critical points and integrated atomic properties have been derived from theoretical densities calculated for the compounds NaCl and TTF-2,5Cl2BQ, thus covering the different kinds of chemical bonds: ionic, covalent, hydrogen bonds and other intermolecular contacts.
3D game engine design a practical approach to real-time computer graphics
Eberly, David H
2006-01-01
A major revision of the international bestseller on game programming!Graphics hardware has evolved enormously in the last decade. Hardware can now be directly controlled through techniques such as shader programming, which requires an entirely new thought process of a programmer. 3D Game Engine Design, Second Edition shows step-by-step how to make a shader-based graphics engine and how to tame the new technology. Much new material has been added, including more than twice the coverage of the essential techniques of scene graph management, as well as new methods for manag
Steam generator experiment for 3-D computer code qualification - CLOTAIRE international program
The current 1988/89 test program does focus on the production of accurate data sets dedicated to the qualifications of both 3-D thermalhydraulic codes and flow induced vibration predictive tools. In order to meet these challenging objectives the test program includes: detailed measurements of two-phase flow distributions relying on advanced optical probe techniques, throughout the bundle straight part; investigations at the same time of flow distributions and of the tubes' vibratory responses, in the U-band region; for a limited number of preselected positions, measurements of the emulsion's changing characteristics during transient sequences similar to those in an actual plant. (orig./DG)
Computer Simulation of Flow in CSO “OK3D Evropská”
Pollert, J
2000-01-01
During the last 30 years, a number of devices has been developed for dynamic separation of settle able solids in wastewaters. Initially, these separators were used for control of Combined Sewer Overflow (CSO) pollution by retaining the bulk of solids in the underflow, directed to the sewage treatment plant (STP), and allowing combined sewage with reduced pollutant loads to overflow from the sewer systém. This paper is describing CSO “OK 3D Evropská” in Prague 6 on Evropská Street. Inlet...
Implementation of Headtracking and 3D Stereo with Unity and VRPN for Computer Simulations
Noyes, Matthew A.
2013-01-01
This paper explores low-cost hardware and software methods to provide depth cues traditionally absent in monocular displays. The use of a VRPN server in conjunction with a Microsoft Kinect and/or Nintendo Wiimote to provide head tracking information to a Unity application, and NVIDIA 3D Vision for retinal disparity support, is discussed. Methods are suggested to implement this technology with NASA's EDGE simulation graphics package, along with potential caveats. Finally, future applications of this technology to astronaut crew training, particularly when combined with an omnidirectional treadmill for virtual locomotion and NASA's ARGOS system for reduced gravity simulation, are discussed.
World's first ABWR start-up test analysis with 3-D transient computational code
The Kashiwazaki-Kariwa Nuclear Power Station Unit 6, the world's first Advanced BWR (ABWR), began commercial operation from November 1996 following one year of start-up tests. A large number of variables which may be used to validate the advanced design features were obtained from transient tests. These test data are now being used for the qualification of TRACG, a BWR 3-D transient analysis code. Calculated results show that TRACG is fully capable of accurately predicting ABWR transient response and will be useful for application to future plant designs
Salih Sinan Gültekin; Ahmet Oğuz Hasdemir; Emine Öztürk
2016-01-01
We herein present our first experience obtained by 3D freehand single-photon emission computed tomography (SPECT) (F-SPECT) guidance for sentinel lymph node detection (SLND) in two patients with early stage breast cancer. F-SPECT guidance was carried out using one-day protocol in one case and by the two-day protocol in the other one. SLND was performed successfully in both patients. Histopathologic evaluation showed that the excised nodes were tumor negative. Thus, patients underw...
The role of computer-aided design in the learning of practical 3D-descriptive geometry: a case study
Edwards, Geoffrey Alan
1988-01-01
There are a number of problems surrounding the teaching of practical 3-D descriptive geometry to children in secondary education, notably the difficulty pupils have with visualising an object's form from orthographic views, and the interpretation of an object's geometric attributes into the descriptive geometry representation. The purpose of the current research is to evaluate the use of computer-aided design in this area of the curriculum and is based upon work under...
Parameswaran, Harikrishnan; Majumdar, Arnab; Suki, Béla
2011-01-01
Pulmonary emphysema is a connective tissue disease characterized by the progressive destruction of alveolar walls leading to airspace enlargement and decreased elastic recoil of the lung. However, the relationship between microscopic tissue structure and decline in stiffness of the lung is not well understood. In this study, we developed a 3D computational model of lung tissue in which a pre-strained cuboidal block of tissue was represented by a tessellation of space filling polyhedra, with e...
Harikrishnan Parameswaran; Arnab Majumdar; Béla Suki
2011-01-01
Pulmonary emphysema is a connective tissue disease characterized by the progressive destruction of alveolar walls leading to airspace enlargement and decreased elastic recoil of the lung. However, the relationship between microscopic tissue structure and decline in stiffness of the lung is not well understood. In this study, we developed a 3D computational model of lung tissue in which a pre-strained cuboidal block of tissue was represented by a tessellation of space filling polyhedra, with e...
Eichenlaub, Jesse B.
1995-03-01
Mounting a lenticular lens in front of a flat panel display is a well known, inexpensive, and easy way to create an autostereoscopic system. Such a lens produces half resolution 3D images because half the pixels on the LCD are seen by the left eye and half by the right eye. This may be acceptable for graphics, but it makes full resolution text, as displayed by common software, nearly unreadable. Very fine alignment tolerances normally preclude the possibility of removing and replacing the lens in order to switch between 2D and 3D applications. Lenticular lens based displays are therefore limited to use as dedicated 3D devices. DTI has devised a technique which removes this limitation, allowing switching between full resolution 2D and half resolution 3D imaging modes. A second element, in the form of a concave lenticular lens array whose shape is exactly the negative of the first lens, is mounted on a hinge so that it can be swung down over the first lens array. When so positioned the two lenses cancel optically, allowing the user to see full resolution 2D for text or numerical applications. The two lenses, having complementary shapes, naturally tend to nestle together and snap into perfect alignment when pressed together--thus obviating any need for user operated alignment mechanisms. This system represents an ideal solution for laptop and notebook computer applications. It was devised to meet the stringent requirements of a laptop computer manufacturer including very compact size, very low cost, little impact on existing manufacturing or assembly procedures, and compatibility with existing full resolution 2D text- oriented software as well as 3D graphics. Similar requirements apply to high and electronic calculators, several models of which now use LCDs for the display of graphics.
Schmitt, Mayka; Halisch, Matthias; Müller, Cornelia; Peres Fernandes, Celso
2016-02-01
Recent years have seen a growing interest in the characterization of the pore morphologies of reservoir rocks and how the spatial organization of pore traits affects the macro behavior of rock-fluid systems. With the availability of 3-D high-resolution imaging, such as x-ray micro-computed tomography (µ-CT), the detailed quantification of particle shapes has been facilitated by progress in computer science. Here, we show how the shapes of irregular rock particles (pores) can be classified and quantified based on binary 3-D images. The methodology requires the measurement of basic 3-D particle descriptors (length, width, and thickness) and a shape classification that involves the similarity of artificial objects, which is based on main pore network detachments and 3-D sample sizes. Two main pore components were identified from the analyzed volumes: pore networks and residual pore ganglia. A watershed algorithm was applied to preserve the pore morphology after separating the main pore networks, which is essential for the pore shape characterization. The results were validated for three sandstones (S1, S2, and S3) from distinct reservoirs, and most of the pore shapes were found to be plate- and cube-like, ranging from 39.49 to 50.94 % and from 58.80 to 45.18 % when the Feret caliper descriptor was investigated in a 10003 voxel volume. Furthermore, this study generalizes a practical way to correlate specific particle shapes, such as rods, blades, cuboids, plates, and cubes to characterize asymmetric particles of any material type with 3-D image analysis.
Computer Simulation of Flow in CSO “OK3D Evropská”
J. Pollert
2000-01-01
Full Text Available During the last 30 years, a number of devices has been developed for dynamic separation of settle able solids in wastewaters. Initially, these separators were used for control of Combined Sewer Overflow (CSO pollution by retaining the bulk of solids in the underflow, directed to the sewage treatment plant (STP, and allowing combined sewage with reduced pollutant loads to overflow from the sewer systém. This paper is describing CSO “OK 3D Evropská” in Prague 6 on Evropská Street. Inlet to CSO is 3 m diameter tube collecting water from location of Oepy, Vokovice, Liboc and Ruzyně. The outflow throttle pipe is 1.1 m in diameter and continues to central wastewater treatment plant and overflow is ending in Šárecký creek. Šárecký creek flows through the Šárka valley which is environmentally protected area. CSO “OK 3D Evropská" has high overflow crest and probability of the function is 0.44 per year.
Fabrication of computationally designed scaffolds by low temperature 3D printing
The development of artificial bone substitutes that mimic the properties of bone and simultaneously promote the desired tissue regeneration is a current issue in bone tissue engineering research. An approach to create scaffolds with such characteristics is based on the combination of novel design and additive manufacturing processes. The objective of this work is to characterize the microstructural and the mechanical properties of scaffolds developed by coupling both topology optimization and a low temperature 3D printing process. The scaffold design was obtained using a topology optimization approach to maximize the permeability with constraints on the mechanical properties. This procedure was studied to be suitable for the fabrication of a cage prototype for tibial tuberosity advancement application, which is one of the most recent and promising techniques to treat cruciate ligament rupture in dogs. The microstructural and mechanical properties of the scaffolds manufactured by reacting α/β-tricalcium phosphate with diluted phosphoric acid were then assessed experimentally and the scaffolds strength reliability was determined. The results demonstrate that the low temperature 3D printing process is a reliable option to create synthetic scaffolds with tailored properties, and when coupled with topology optimization design it can be a powerful tool for the fabrication of patient-specific bone implants. (paper)
Advanced Multi-modal User Interfaces in 3D Computer Graphics and Virtual Reality
Chen, Yenan
2012-01-01
Computers are developed continuously to satisfy the human demands, and typical tools used everywhere for ranging from daily life usage to all kinds of research. Virtual Reality (VR), a virtual environment simulated to present physical presence in the real word and imaginary worlds, has been widely applied to simulate the virtual environment. People’s feeling is limited to visual perception when only computers are applied for simulations, since computers are limited to display visualization of...
Casting directly from a computer model by using advanced simulation software FLOW-3D Cast ®
M. Sirviö
2009-01-01
Full Text Available ConiferRob - A patternless casting technique, originally conceived at VTT Technical Research Centre of Finland and furtherdeveloped at its spin-off company, Simtech Systems, offers up to 40% savings in product development costs, and up to two months shorterdevelopment times compared to conventional techniques. Savings of this order can be very valuable on today's highly competitivemarkets. Casting simulation is commonly used for designing of casting systems. However, most of the software are today old fashioned and predicting just shrinkage porosity. Flow Science, VTT and Simtech have developed new software called FLOW-3D Cast ® , whichcan simulate surface defects, air entrainment, filters, core gas problems and even a cavitation.
Pratik Raval
2014-02-01
Full Text Available To date inductively coupled power transfer (ICPT systems have already found many practical applications including battery charging pads. In fact, current charging platforms tend to largely support only one- or two-dimensional planar movement in load. This paper proposes a new concept of extending the aspect ratios of the operating power transfer volume of ICPT systems to support arbitrary three dimensional load movements with respect to the primary coils. This is done by use of modern finite element method analysis software to propose the primary and secondary magnetic structures of such an ICPT system. Firstly, two primary magnetic structures are proposed based on contrasting modes of operation and different field directions. This includes a single-phase and multi-phase current model. Next, a secondary magnetic structure is customized to be compatible with both primary structures. The resulting system is shown to produce a 3D power transfer volume for battery cell charging applications.
Dai, Gaoming; Mishnaevsky, Leon, Jr.
2014-01-01
3D numerical simulations of fatigue damage of multiscale fiber reinforced polymer composites with secondary nanoclay reinforcement are carried out. Macro–micro FE models of the multiscale composites are generated automatically using Python based software. The effect of the nanoclay reinforcement...... (localized in the fiber/matrix interface (fiber sizing) and distributed throughout the matrix) on the crack path, damage mechanisms and fatigue behavior is investigated in numerical experiments. It was observed that the composites with secondary nanoreinforcement localized in the fiber sizing ensure higher...... lifetime and damage resistance than those with nanoreinforcement dispersed throughout the matrix. Crack bridging by nanoparticles was observed mainly in composites with randomly oriented nanoplatelets and clusters, while the crack path deviation was strongest in the composites with aligned nanoplatelets...
Computer aided moiré topography of 3D models of set of teeth
Bartoněk, L.; Keprt, Jiří
Bellingham: SPIE - The International Society for Optical Engineering, 2008 - (Popiolek-Masajada, A.; Jankowska, E.; Urbanczyk, W.), 71411C/1-71411C/8. (Proceedings of SPIE. 7141). ISBN 978-0-8194-7383-7. ISSN 0277-786X. [Polish-Slovak-Czech Optical Conference on Wave and Quantum Aspects of Contemporary Optics /16./. Polanica Zdrój (PL), 08.09.2008-12.09.2008] R&D Projects: GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : interference laser beam * moiré fringes * contour lines * original phase * 3D imagine of space surfaces * wire frame surfaces Subject RIV: BH - Optics, Masers, Laser s http://dx.doi.org/10.1117/12.822393
Factors Affecting the Precision of Electrostatic Computation of 3D MEMS Structures
Majumdar, N
2006-01-01
Micro-Electro-Mechanical Systems (MEMS) normally have fixed or moving structures (plates or array of thin beams) with cross-sections of the order of microns and lengths of the order of tens or hundreds of microns. Electrostatic forces play a very major role in maneuvering these devices, and hence, a thorough understanding of the electrostatic properties of these structures is of critical importance. Recently, a nearly exact boundary element method (neBEM) solver has been developed and used to solve difficult problems related to electrostatics of various devices. Because of the exact foundation expressions, this solver has been found to be very accurate while solving critical problems which normally necessitate special formulations involving elegant, but difficult mathematics. In this work, we investigate the effects of various possible approximations on the 3D electrostatic solutions obtained for MEMS structures. In particular, we investigate the effects of discretization, omission of surfaces with small amou...
CasimirSim - A Tool to Compute Casimir Polder Forces for Nontrivial 3D Geometries
The so-called Casimir effect is one of the most interesting macro-quantum effects. Being negligible on the macro-scale it becomes a governing factor below structure sizes of 1 μm where it accounts for typically 100 kN m-2. The force does not depend on gravity, or electric charge but solely on the materials properties, and geometrical shape. This makes the effect a strong candidate for micro(nano)-mechanical devices M(N)EMS. Despite a long history of research the theory lacks a uniform description valid for arbitrary geometries which retards technical application. We present an advanced state-of-the-art numerical tool overcoming all the usual geometrical restrictions, capable of calculating arbitrary 3D geometries by utilizing the Casimir Polder approximation for the Casimir force
3D CFD computations of trasitional flows using DES and a correlation based transition model
Sørensen, Niels N.; Bechmann, Andreas; Zahle, Frederik
2011-01-01
The present article describes the application of the correlation based transition model of Menter et al. in combination with the Detached Eddy Simulation (DES) methodology to two cases with large degree of flow separation typically considered difficult to compute. Firstly, the flow is computed over...
Sofronov, I.D.; Voronin, B.L.; Butnev, O.I. [VNIIEF (Russian Federation)] [and others
1997-12-31
The aim of the work performed is to develop a 3D parallel program for numerical calculation of gas dynamics problem with heat conductivity on distributed memory computational systems (CS), satisfying the condition of numerical result independence from the number of processors involved. Two basically different approaches to the structure of massive parallel computations have been developed. The first approach uses the 3D data matrix decomposition reconstructed at temporal cycle and is a development of parallelization algorithms for multiprocessor CS with shareable memory. The second approach is based on using a 3D data matrix decomposition not reconstructed during a temporal cycle. The program was developed on 8-processor CS MP-3 made in VNIIEF and was adapted to a massive parallel CS Meiko-2 in LLNL by joint efforts of VNIIEF and LLNL staffs. A large number of numerical experiments has been carried out with different number of processors up to 256 and the efficiency of parallelization has been evaluated in dependence on processor number and their parameters.
Mishnaevsky, Leon; Dai, Gaoming
2014-01-01
Hybrid and hierarchical polymer composites represent a promising group of materials for engineering applications. In this paper, computational studies of the strength and damage resistance of hybrid and hierarchical composites are reviewed. The reserves of the composite improvement are explored b...
Zhang, Mian; Huang, Cheng-li
2012-08-01
Generalized spherical harmonics (GSH) are usually applied on the problems where the Earth model is elliptical and elastic stress tensor is involved in, as stress tensor can’t be represented in vector spherical harmonics. However, the divergence of the te ns or and a vector dot - product with the tensor are only needed on computation rotation modes of the Earth which can be written in the vector spherical harmonics. We extend the equations on the spherical Earth to asymmetric 3D model by means of linear operator method. This method doesn’t use the complicated generalized spherical harmonics nor Wigner 3 - j symbol. As a validation of this method, the practical calculation of rotational modes of 3D Earth will be made and discussed.
Kaga, Akimune; Murotsuki, Jun; Kamimura, Miki; Kimura, Masato; Saito-Hakoda, Akiko; Kanno, Junko; Hoshi, Kazuhiko; Kure, Shigeo; Fujiwara, Ikuma
2015-05-01
Achondroplasia and Down syndrome are relatively common conditions individually. But co-occurrence of both conditions in the same patient is rare and there have been no reports of fetal analysis of this condition by prenatal sonographic and three-dimensional (3-D) helical computed tomography (CT). Prenatal sonographic findings seen in persons with Down syndrome, such as a thickened nuchal fold, cardiac defects, and echogenic bowel were not found in the patient. A prenatal 3-D helical CT revealed a large head with frontal bossing, metaphyseal flaring of the long bones, and small iliac wings, which suggested achondroplasia. In a case with combination of achondroplasia and Down syndrome, it may be difficult to diagnose the co-occurrence prenatally without typical markers of Down syndrome. PMID:25385298
Novel Kinetic 3D MHD Algorithm for High Performance Parallel Computing Systems
Chetverushkin, B; Saveliev, V
2013-01-01
The impressive progress of the kinetic schemes in the solution of gas dynamics problems and the development of effective parallel algorithms for modern high performance parallel computing systems led to the development of advanced methods for the solution of the magnetohydrodynamics problem in the important area of plasma physics. The novel feature of the method is the formulation of the complex Boltzmann-like distribution function of kinetic method with the implementation of electromagnetic interaction terms. The numerical method is based on the explicit schemes. Due to logical simplicity and its efficiency, the algorithm is easily adapted to modern high performance parallel computer systems including hybrid computing systems with graphic processors.
Rudolph, Tobias; Ebert, Lars; Kowal, Jens
2006-03-01
Supporting surgeons in performing minimally invasive surgeries can be considered as one of the major goals of computer assisted surgery. Excellent intraoperative visualization is a prerequisite to achieve this aim. The Siremobil Iso-C 3D has become a widely used imaging device, which, in combination with a navigation system, enables the surgeon to directly navigate within the acquired 3D image volume without any extra registration steps. However, the image quality is rather low compared to a CT scan and the volume size (approx. 12 cm 3) limits its application. A regularly used alternative in computer assisted orthopedic surgery is to use of a preoperatively acquired CT scan to visualize the operating field. But, the additional registration step, necessary in order to use CT stacks for navigation is quite invasive. Therefore the objective of this work is to develop a noninvasive registration technique. In this article a solution is being proposed that registers a preoperatively acquired CT scan to the intraoperatively acquired Iso-C 3D image volume, thereby registering the CT to the tracked anatomy. The procedure aligns both image volumes by maximizing the mutual information, an algorithm that has already been applied to similar registration problems and demonstrated good results. Furthermore the accuracy of such a registration method was investigated in a clinical setup, integrating a navigated Iso-C 3D in combination with an tracking system. Initial tests based on cadaveric animal bone resulted in an accuracy ranging from 0.63mm to 1.55mm mean error.
Yagüe-Fabra, J.A.; Ontiveros, S.; Jiménez, R.; Chitchian, S.; Tosello, Guido; Carmignato, S.
2013-01-01
Many factors influence the measurement uncertainty when using computed tomography for dimensional metrology applications. One of the most critical steps is the surface extraction phase. An incorrect determination of the surface may significantly increase the measurement uncertainty. This paper pr...
A 3-D admittance-level computational model of a rat hippocampus for improving prosthetic design.
Gilbert, Andrew; Loizos, Kyle; RamRakhyani, Anil Kumar; Hendrickson, Phillip; Lazzi, Gianluca; Berger, Theodore W
2015-08-01
Hippocampal prosthetic devices have been developed to bridge the gap between functioning portions of the hippocampus, in order to restore lost memory functionality in those suffering from brain injury or diseases. One approach taken in recent neuroprosthetic design is to use a multi-input, multi-output device that reads data from the CA3 in the hippocampus and electrically stimulates the CA1 in an attempt to mimic the appropriate firing pattern that would occur naturally between the two areas. However, further study needs to be conducted in order to optimize electrode placement, pulse magnitude, and shape for creating the appropriate firing pattern. This paper describes the creation and implementation of an anatomically correct 3D model of the hippocampus to simulate the electric field patterns and axonal activation from electrical stimulation due to an implanted electrode array. The activating function was applied to the voltage results to determine the firing patterns in possible axon locations within the CA1. PMID:26736751
3D-MAPTOR Code for Computation of Magnetic Fields in Tokamaks
Full text: A 3D code has been developed in order to simulate the magnetic field lines in tokamaks, in two versions. In the first one, the toroidal magnetic field can be obtained from the individual fields of circular coils arranged around the torus, or alternatively, as a ripple-less field. The poloidal field is provided by a given toroidal current density profile. In an upgraded version, rectangular toroidal field coils and D-shaped plasma cross sections have been included, in order to aid in the design of spherical tokamaks. Proposing initial conditions for magnetic filed lines, they are integrated along the toroidal angle coordinate, and Poincare maps can be obtained at any desired cross section plane along the toroidal coordinate. The evolution of the field lines is also monitored from above, so the ripple due to the toroidal field coils can be appreciated. The effects of loss of axisymmetry, either originated by ripples, or by additional external coils, such as an inner coil with tilted circular loops, can therefore be studied. This is useful for the study of breaking-up of external surfaces, as in the case of ergodic divertors. The code can also be used in order to reconstruct the evolution of the plasma column, using the experimental signals of tokamak discharges. In the latter case, the results have been compared with tomographic results of the ISTTOK tokamak. (author)
Frédéric Boudon
2015-01-01
Full Text Available The link between genetic regulation and the definition of form and size during morphogenesis remains largely an open question in both plant and animal biology. This is partially due to the complexity of the process, involving extensive molecular networks, multiple feedbacks between different scales of organization and physical forces operating at multiple levels. Here we present a conceptual and modeling framework aimed at generating an integrated understanding of morphogenesis in plants. This framework is based on the biophysical properties of plant cells, which are under high internal turgor pressure, and are prevented from bursting because of the presence of a rigid cell wall. To control cell growth, the underlying molecular networks must interfere locally with the elastic and/or plastic extensibility of this cell wall. We present a model in the form of a three dimensional (3D virtual tissue, where growth depends on the local modulation of wall mechanical properties and turgor pressure. The model shows how forces generated by turgor-pressure can act both cell autonomously and non-cell autonomously to drive growth in different directions. We use simulations to explore lateral organ formation at the shoot apical meristem. Although different scenarios lead to similar shape changes, they are not equivalent and lead to different, testable predictions regarding the mechanical and geometrical properties of the growing lateral organs. Using flower development as an example, we further show how a limited number of gene activities can explain the complex shape changes that accompany organ outgrowth.
Geometric Neural Computing for 2D Contour and 3D Surface Reconstruction
Rivera-Rovelo, Jorge; Bayro-Corrochano, Eduardo; Dillmann, Ruediger
In this work we present an algorithm to approximate the surface of 2D or 3D objects combining concepts from geometric algebra and artificial neural networks. Our approach is based on the self-organized neural network called Growing Neural Gas (GNG), incorporating versors of the geometric algebra in its neural units; such versors are the transformations that will be determined during the training stage and then applied to a point to approximate the surface of the object. We also incorporate the information given by the generalized gradient vector flow to select automatically the input patterns, and also in the learning stage in order to improve the performance of the net. Several examples using medical images are presented, as well as images of automatic visual inspection. We compared the results obtained using snakes against the GSOM incorporating the gradient information and using versors. Such results confirm that our approach is very promising. As a second application, a kind of morphing or registration procedure is shown; namely the algorithm can be used when transforming one model at time t 1 into another at time t 2. We include also examples applying the same procedure, now extended to models based on spheres.
Jets in coronal holes: Hinode observations and 3D computer modelling
Moreno-Insertis, F; Ugarte-Urra, I
2007-01-01
Recent observations of coronal hole areas with the XRT and EIS instruments onboard the Hinode satellite have shown with unprecedented detail the launching of fast, hot jets away from the solar surface. In some cases these events coincide with episodes of flux emergence from beneath the photosphere. In this letter we show results of a 3D numerical experiment of flux emergence from the solar interior into a coronal hole and compare them with simultaneous XRT and EIS observations of a jet-launching event that accompanied the appearance of a bipolar region in MDI magnetograms. The magnetic skeleton and topology that result in the experiment bear a strong resemblance to linear force-fee extrapolations of the SOHO/MDI magnetograms. A thin current sheet is formed at the boundary of the emerging plasma. A jet is launched upward along the open reconnected field lines with values of temperature, density and velocity in agreement with the XRT and EIS observations. Below the jet, a split-vault structure results with two ...
Soft Computing Based Point Correspondence Matching for Automatic 3D Reconstruction
Annamária R. Várkonyi-Kóczy
2005-06-01
Full Text Available In computer vision image point correspondence matching plays an importantrole. With the help of the point correspondence matching algorithms for example some ofmethods concerning the field of stereo vision can be automatized. This paper presents amethod for quickly and reliably selecting and matching of the most interesting image points(feature points.
Mendrik, A.M.; Vonken, E.J.; Rutten, A.; Viergever, M.A.; Ginneken, B. van
2009-01-01
Noise filtering techniques that maintain image contrast while decreasing image noise have the potential to optimize the quality of computed tomography (CT) images acquired at reduced radiation dose. In this paper, a hybrid diffusion filter with continuous switch (HDCS) is introduced, which exploits
A computational model for estimating tumor margins in complementary tactile and 3D ultrasound images
Shamsil, Arefin; Escoto, Abelardo; Naish, Michael D.; Patel, Rajni V.
2016-03-01
Conventional surgical methods are effective for treating lung tumors; however, they impose high trauma and pain to patients. Minimally invasive surgery is a safer alternative as smaller incisions are required to reach the lung; however, it is challenging due to inadequate intraoperative tumor localization. To address this issue, a mechatronic palpation device was developed that incorporates tactile and ultrasound sensors capable of acquiring surface and cross-sectional images of palpated tissue. Initial work focused on tactile image segmentation and fusion of position-tracked tactile images, resulting in a reconstruction of the palpated surface to compute the spatial locations of underlying tumors. This paper presents a computational model capable of analyzing orthogonally-paired tactile and ultrasound images to compute the surface circumference and depth margins of a tumor. The framework also integrates an error compensation technique and an algebraic model to align all of the image pairs and to estimate the tumor depths within the tracked thickness of a palpated tissue. For validation, an ex vivo experimental study was conducted involving the complete palpation of 11 porcine liver tissues injected with iodine-agar tumors of varying sizes and shapes. The resulting tactile and ultrasound images were then processed using the proposed model to compute the tumor margins and compare them to fluoroscopy based physical measurements. The results show a good negative correlation (r = -0.783, p = 0.004) between the tumor surface margins and a good positive correlation (r = 0.743, p = 0.009) between the tumor depth margins.
A continuation method for computing non-linear 3-D free surface flows
Petersson, N.A.
1993-01-01
The subject of this paper is a pseudo-arclength continuation method for computing non-linear three-dimensional steady potential flow around a submerged body moving in a infinitely deep liquid at constant speed and distance below the free surface.
Kressler, Bryan; Spincemaille, Pascal; Prince, Martin R; Wang, Yi
2006-09-01
Time-resolved 3D MRI with high spatial and temporal resolution can be achieved using spiral sampling and sliding-window reconstruction. Image reconstruction is computationally intensive because of the need for data regridding, a large number of temporal phases, and multiple RF receiver coils. Inhomogeneity blurring correction for spiral sampling further increases the computational work load by an order of magnitude, hindering the clinical utility of spiral trajectories. In this work the reconstruction time is reduced by a factor of >40 compared to reconstruction using a single processor. This is achieved by using a cluster of 32 commercial off-the-shelf computers, commodity networking hardware, and readily available software. The reconstruction system is demonstrated for time-resolved spiral contrast-enhanced (CE) peripheral MR angiography (MRA), and a reduction of reconstruction time from 80 min to 1.8 min is achieved. PMID:16892189
On the computation of long period seismograms in a 3-D earth using normal mode based approximations
Romanowicz, Barbara A.; Panning, Mark P.; Gung, Yuancheng; Capdeville, Yann
2008-11-01
Tomographic inversions for large-scale structure of the earth's mantle involve a forward modelling step of wave propagation through 3-D heterogeneity. Until now, most investigators have worked in the framework of the simplest theoretical assumptions, namely the infinite frequency `ray theory' in the case of body wave traveltime inversions, or the `path-average' approximation (PAVA) to normal mode perturbation theory, in the case of surface waves and long-period waveforms. As interest is shifting to mapping shorter wavelength structures, the need for a more accurate theoretical account of the interaction of seismic waves with mantle heterogeneity, coupled with improvements in path coverage, has been realized. Here we discuss different levels of approximations used in the context of normal mode perturbation theory, when modelling time domain seismic waveforms. We compare the performance of asymptotic approximations, which collapse the effects of 3-D structure onto the great circle vertical plane: the 1-D PAVA and a 2-D approximation called non-linear asymptotic coupling theory (NACT), which both are zeroth order asymptotic approximations. We then discuss how off-vertical plane effects can be introduced using higher order asymptotics. These computationally efficient approximations are compared to the linear Born formalism (BORN), which computes scattering integrals over the entire surface of the sphere. We point out some limitations of this linear formalism in the case of spatially extended anomalies, and show how that can be remedied through the introduction of a non-linear term (NBORN). All these approximations are referenced to a precise 3-D numerical computation afforded by the spectral element method. We discuss simple geometries, and explore a range of sizes of anomalies compared to the wavelength of the seismic waves considered, thus illustrating the range of validity and limitations of the various approximations considered.
Computation of eddy currents in a solid rotor induction machine with 2-D and 3-D FEM
Silwal, Bishal
2012-01-01
Although a two-dimensional numerical analysis of an electrical machine provides an approximately accurate solution of the electromagnetic field in the machine, a three-dimensional study is needed to understand the actual phenomena. But due to the large problem size and the complex geometries, the three dimensional model requires a huge amount of degrees of freedoms (DoFs) to be solved, which is not possible with a limited computing resources. Therefore, a coupled 2D-3D model can be the best a...
High-Performance Computation of Distributed-Memory Parallel 3D Voronoi and Delaunay Tessellation
Peterka, Tom; Morozov, Dmitriy; Phillips, Carolyn
2014-11-14
Computing a Voronoi or Delaunay tessellation from a set of points is a core part of the analysis of many simulated and measured datasets: N-body simulations, molecular dynamics codes, and LIDAR point clouds are just a few examples. Such computational geometry methods are common in data analysis and visualization; but as the scale of simulations and observations surpasses billions of particles, the existing serial and shared-memory algorithms no longer suffice. A distributed-memory scalable parallel algorithm is the only feasible approach. The primary contribution of this paper is a new parallel Delaunay and Voronoi tessellation algorithm that automatically determines which neighbor points need to be exchanged among the subdomains of a spatial decomposition. Other contributions include periodic and wall boundary conditions, comparison of our method using two popular serial libraries, and application to numerous science datasets.
Solving linear systems in FLICA-4, thermohydraulic code for 3-D transient computations
FLICA-4 is a computer code, developed at the CEA (France), devoted to steady state and transient thermal-hydraulic analysis of nuclear reactor cores, for small size problems (around 100 mesh cells) as well as for large ones (more than 100000), on, either standard workstations or vector super-computers. As for time implicit codes, the largest time and memory consuming part of FLICA-4 is the routine dedicated to solve the linear system (the size of which is of the order of the number of cells). Therefore, the efficiency of the code is crucially influenced by the optimization of the algorithms used in assembling and solving linear systems: direct methods as the Gauss (or LU) decomposition for moderate size problems, iterative methods as the preconditioned conjugate gradient for large problems. 6 figs., 13 refs
Application of high magnification to 3D x-ray computed tomography
A system was previously described for direct three-dimensional x-ray computed tomography which embodies both a means of performing reconstruction from cone-beam projection data and a means of acquiring such data. After replacing the microfocus source the system resolution under standard conditions is now determined primarily by the spatial resolution of the x-ray image intensifier which serves as the two dimensional detector. To more fully exploit the potential of the x-ray source and to bypass the limits of the detection system the use of high geometric magnification was explored. Initial findings are presented for both a conventional full-field configuration and a configuration in which only a limited volume of a sample can be reconstructed. The results indicate the utility of combining aspects of microradiography with those of computed tomography
EVALUATION OF THE LIVER METASTASIS BY 3D-COMPUTED TOMOGRAPHY
Iuliana Eva; R.C. Tiutiuca
2005-01-01
Abdominal spiral computed tomography is the method of choice for the diagnosis of hepatic metastasis, evaluating lesions even under 10 mm. Treatment depends of the hepatic and extrahepatic spread of disease. Therapeutical options include surgical ablation (resection, enucleation, crioablation, radiofrequency, liver transplant) or non-surgical (embolization or chemoembolization, therapeutic aproach through the hepatic artery). Precise diagnostic and evaluation of the extension of the disease...
Computation of stationary 3D halo currents in fusion devices with accuracy control
Bettini, Paolo; Specogna, Ruben
2014-09-01
This paper addresses the calculation of the resistive distribution of halo currents in three-dimensional structures of large magnetic confinement fusion machines. A Neumann electrokinetic problem is solved on a geometry so complicated that complementarity is used to monitor the discretization error. An irrotational electric field is obtained by a geometric formulation based on the electric scalar potential, whereas three geometric formulations are compared to obtain a solenoidal current density: a formulation based on the electric vector potential and two geometric formulations inspired from mixed and mixed-hybrid Finite Elements. The electric vector potential formulation is usually considered impractical since an enormous computing power is wasted by the topological pre-processing it requires. To solve this challenging problem, we present novel algorithms based on lazy cohomology generators that enable to save orders of magnitude computational time with respect to all other state-of-the-art solutions proposed in literature. Believing that our results are useful in other fields of scientific computing, the proposed algorithm is presented as a detailed pseudocode in such a way that it can be easily implemented.
Accurate 3-D finite difference computation of traveltimes in strongly heterogeneous media
Noble, M.; Gesret, A.; Belayouni, N.
2014-12-01
Seismic traveltimes and their spatial derivatives are the basis of many imaging methods such as pre-stack depth migration and tomography. A common approach to compute these quantities is to solve the eikonal equation with a finite-difference scheme. If many recently published algorithms for resolving the eikonal equation do now yield fairly accurate traveltimes for most applications, the spatial derivatives of traveltimes remain very approximate. To address this accuracy issue, we develop a new hybrid eikonal solver that combines a spherical approximation when close to the source and a plane wave approximation when far away. This algorithm reproduces properly the spherical behaviour of wave fronts in the vicinity of the source. We implement a combination of 16 local operators that enables us to handle velocity models with sharp vertical and horizontal velocity contrasts. We associate to these local operators a global fast sweeping method to take into account all possible directions of wave propagation. Our formulation allows us to introduce a variable grid spacing in all three directions of space. We demonstrate the efficiency of this algorithm in terms of computational time and the gain in accuracy of the computed traveltimes and their derivatives on several numerical examples.
Computation of stationary 3D halo currents in fusion devices with accuracy control
Bettini, Paolo, E-mail: paolo.bettini@unipd.it [Università degli Studi di Padova, Dipartimento di Ingegneria Industriale (DII), Via Gradenigo 6/A, 35131 Padova (Italy); Consorzio RFX, C.so Stati Uniti 4, 35127 Padova (Italy); Specogna, Ruben, E-mail: ruben.specogna@uniud.it [Università degli Studi di Udine, Dipartimento di Ingegneria Elettrica, Gestionale e Meccanica (DIEGM), Via delle Scienze 206, I-33100 Udine (Italy)
2014-09-15
This paper addresses the calculation of the resistive distribution of halo currents in three-dimensional structures of large magnetic confinement fusion machines. A Neumann electrokinetic problem is solved on a geometry so complicated that complementarity is used to monitor the discretization error. An irrotational electric field is obtained by a geometric formulation based on the electric scalar potential, whereas three geometric formulations are compared to obtain a solenoidal current density: a formulation based on the electric vector potential and two geometric formulations inspired from mixed and mixed-hybrid Finite Elements. The electric vector potential formulation is usually considered impractical since an enormous computing power is wasted by the topological pre-processing it requires. To solve this challenging problem, we present novel algorithms based on lazy cohomology generators that enable to save orders of magnitude computational time with respect to all other state-of-the-art solutions proposed in literature. Believing that our results are useful in other fields of scientific computing, the proposed algorithm is presented as a detailed pseudocode in such a way that it can be easily implemented.
Ballhausen, Hendrik; Hieber, Sheila; Li, Minglun; Belka, Claus; Reiner, Michael [University Hospital of LMU, Department of Radiation Oncology, Munich (Germany); Parodi, Katia [Ludwig-Maximilian-University, Department of Experimental Physics - Medical Physics, Munich (Germany)
2015-05-01
Three-dimensional ultrasound (3D-US) is a modality complementary to kilovoltage cone beam computed tomography (kV-CBCT) and skin markers for patient positioning detection. This study compares the linearity of evaluations based on measurements using a modern 3D-US system (Elekta Clarity {sup registered}; Elekta, Stockholm, Sweden), a kV-CBCT system (Elekta iView {sup registered}), and skin markers. An investigator deliberately displaced a multimodal phantom by up to ± 30 mm along different axes. The following data points were acquired: 27 along the lateral axis, 29 along the longitudinal axis, 27 along the vertical axis, and 27 along the space diagonal. At each of these 110 positions, the displacements according to skin' markers were recorded and scans were performed using both 3D-US and kV-CBCT. Shifts were detected by matching bony anatomy or soft tissue density to a reference planning CT in the case of kV-CBCT and for 3D-US, by matching ultrasound volume data to a reference planning volume. A consensus value was calculated from the average of the four modalities. With respect to this consensus value, the linearity (offset and regression coefficient, i.e., slope), average offset, systematic error, and random error of all four modalities were calculated for each axis. Linearity was similar for all four modalities, with regression coefficients between 0.994 and 1.012, and all offsets below 1 mm. The systematic errors of skin markers and 3D-US were higher than for kV-CBCT, but random errors were similar. In particular, 3D-US demonstrated an average offset of 0.36 mm to the right, 0.08 mm inferiorly, and 0.15 mm anteriorly; the systematic error was 0.36 mm laterally, 0.35 mm longitudinally, and 0.22 mm vertically; the random error was 0.15 mm laterally, 0.30 mm longitudinally, and 0.12 mm vertically. A total of 109 out of 110 (99 %) 3D-US measurements were within 1 mm of the consensus value on either axis. The linearity of 3D-US was no worse than that of skin
Martinez, M.; Miro, R.; Barrachina, T.; Verdu, G.
2011-07-01
This paper presents the results from the calculation of the steady state simulation with model of CFD (computational fluid dynamic) operating under conditions of operation at full power (Hot Full Power). Development and the CFD model results show the usefulness of these codes for calculating 3D of the variable thermohydraulics of these reactors.
A 3D Sweep Hull Algorithm for computing Convex Hulls and Delaunay Triangulation
Sinclair, David
2016-01-01
This paper presents a new O(nlog(n)) algorithm for computing the convex hull of a set of 3 dimensional points. The algorithm first sorts the point in (x,y,z) then incrementally adds sorted points to the convex hull using the constraint that each new point added to the hull can 'see' at least one facet touching the last point added. The reduces the search time for adding new points. The algorithm belongs to the family of swept hull algorithms. While slower than q-hull for the general case it s...
Computer simulation of 2-D and 3-D ion beam extraction and acceleration
Ido, Shunji; Nakajima, Yuji [Saitama Univ., Urawa (Japan). Faculty of Engineering
1997-03-01
The two-dimensional code and the three-dimensional code have been developed to study the physical features of the ion beams in the extraction and acceleration stages. By using the two-dimensional code, the design of first electrode(plasma grid) is examined in regard to the beam divergence. In the computational studies by using the three-dimensional code, the axis-off model of ion beam is investigated. It is found that the deflection angle of ion beam is proportional to the gap displacement of the electrodes. (author)
3D CFD computations of transitional flows using DES and a correlation based transition model
Sørensen, Niels N.
process can be important for the aerodynamic performance. Today, the most widespread approach is to use fully turbulent computations, where the transitional process is ignored and the entire boundary layer on the wings or airfoils is handled by the turbulence model. The correlation based transition model...... has lately shown promising results, and the present paper describes the application of the model to predict the drag and shedding frequency for flow around a cylinder from sub to super-critical Reynolds numbers. Additionally, the model is applied to the flow around the DU-96 airfoil, at high angles of...
Hemmati, Hamidreza; Kamli-Asl, Alireza; Talebpour, Alireza; Shirani, Shapour
2015-12-01
The atherosclerosis disease is one of the major causes of the death in the world. Atherosclerosis refers to the hardening and narrowing of the arteries by plaques. Carotid stenosis is a narrowing or constriction of carotid artery lumen usually caused by atherosclerosis. Carotid artery stenosis can increase risk of brain stroke. Contrast-enhanced Computed Tomography Angiography (CTA) is a minimally invasive method for imaging and quantification of the carotid plaques. Manual segmentation of carotid lumen in CTA images is a tedious and time consuming procedure which is subjected to observer variability. As a result, there is a strong and growing demand for developing computer-aided carotid segmentation procedures. In this study, a novel method is presented for carotid artery lumen segmentation in CTA data. First, the mean shift smoothing is used for uniformity enhancement of gray levels. Then with the help of three seed points, the centerlines of the arteries are extracted by a 3D Hessian based fast marching shortest path algorithm. Finally, a 3D Level set function is performed for segmentation. Results on 14 CTA volumes data show 85% of Dice similarity and 0.42 mm of mean absolute surface distance measures. Evaluation shows that the proposed method requires minimal user intervention, low dependence to gray levels changes in artery path, resistance to extreme changes in carotid diameter and carotid branch locations. The proposed method has high accuracy and can be used in qualitative and quantitative evaluation. PMID:26429385
Performance Modeling for 3D Visualization in a Heterogeneous Computing Environment
Bowman, Ian; Shalf, John; Ma, Kwan-Liu; Bethel, Wes
2004-06-30
The visualization of large, remotely located data sets necessitates the development of a distributed computing pipeline in order to reduce the data, in stages, to a manageable size. The required baseline infrastructure for launching such a distributed pipeline is becoming available, but few services support even marginally optimal resource selection and partitioning of the data analysis workflow. We explore a methodology for building a model of overall application performance using a composition of the analytic models of individual components that comprise the pipeline. The analytic models are shown to be accurate on a testbed of distributed heterogeneous systems. The prediction methodology will form the foundation of a more robust resource management service for future Grid-based visualization applications.
Implementation of a 3D plasma particle-in-cell code on a MIMD parallel computer
A three-dimensional plasma particle-in-cell (PIC) code has been implemented on the Intel Delta MIMD parallel supercomputer using the General Concurrent PIC algorithm. The GCPIC algorithm uses a domain decomposition to divide the computation among the processors: A processor is assigned a subdomain and all the particles in it. Particles must be exchanged between processors as they move. Results are presented comparing the efficiency for 1-, 2- and 3-dimensional partitions of the three dimensional domain. This algorithm has been found to be very efficient even when a large fraction (e.g. 30%) of the particles must be exchanged at every time step. On the 512-node Intel Delta, up to 125 million particles have been pushed with an electrostatic push time of under 500 nsec/particle/time step
Users manual for CAFE-3D : a computational fluid dynamics fire code.
Khalil, Imane; Lopez, Carlos; Suo-Anttila, Ahti Jorma (Alion Science and Technology, Albuquerque, NM)
2005-03-01
The Container Analysis Fire Environment (CAFE) computer code has been developed to model all relevant fire physics for predicting the thermal response of massive objects engulfed in large fires. It provides realistic fire thermal boundary conditions for use in design of radioactive material packages and in risk-based transportation studies. The CAFE code can be coupled to commercial finite-element codes such as MSC PATRAN/THERMAL and ANSYS. This coupled system of codes can be used to determine the internal thermal response of finite element models of packages to a range of fire environments. This document is a user manual describing how to use the three-dimensional version of CAFE, as well as a description of CAFE input and output parameters. Since this is a user manual, only a brief theoretical description of the equations and physical models is included.
Large-scale Parallel Unstructured Mesh Computations for 3D High-lift Analysis
Mavriplis, Dimitri J.; Pirzadeh, S.
1999-01-01
A complete "geometry to drag-polar" analysis capability for the three-dimensional high-lift configurations is described. The approach is based on the use of unstructured meshes in order to enable rapid turnaround for complicated geometries that arise in high-lift configurations. Special attention is devoted to creating a capability for enabling analyses on highly resolved grids. Unstructured meshes of several million vertices are initially generated on a work-station, and subsequently refined on a supercomputer. The flow is solved on these refined meshes on large parallel computers using an unstructured agglomeration multigrid algorithm. Good prediction of lift and drag throughout the range of incidences is demonstrated on a transport take-off configuration using up to 24.7 million grid points. The feasibility of using this approach in a production environment on existing parallel machines is demonstrated, as well as the scalability of the solver on machines using up to 1450 processors.
Schmitt, Vivien; Dufresne, Matthieu; Vazquez, Jose; Fischer, Martin; Morin, Antoine
2014-01-01
The aim of this study is to investigate the use of computational fluid dynamics (CFD) to predict the solid separation efficiency of a hydrodynamic separator. The numerical difficulty concerns the discretization of the geometry to simulate both the global behavior and the local phenomena that occur near the screen. In this context, a CFD multiscale approach was used: a global model (at the scale of the device) is used to observe the hydrodynamic behavior within the device; a local model (portion of the screen) is used to determine the local phenomena that occur near the screen. The Eulerian-Lagrangian approach was used to model the particle trajectories in both models. The global model shows the influence of the particles' characteristics on the trapping efficiency. A high density favors the sedimentation. In contrast, particles with small densities (1,040 kg/m(3)) are steered by the hydrodynamic behavior and can potentially be trapped by the separator. The use of the local model allows us to observe the particle trajectories near the screen. A comparison between two types of screens (perforated plate vs expanded metal) highlights the turbulent effects created by the shape of the screen. PMID:24622557
Large-scale computer-generated absorption holograms of 3D objects: II. Practical methodology
Phillips, Nicholas J.; Cameron, Colin D.; Dodd, Adrian K.; Payne, Douglas A.; Sheerin, David T.; Slinger, Christopher W.
1999-03-01
As a support to the advances in theoretical understanding and computational methods, we describe a new laser plotter technique that enables, in principle, an unlimited size of pixel array to be plotted efficiently with a rigorous estimate of duration of the plot run time. Developments in laser plotter design are presented that allow the formation of pixellated holographic structures of high precision (c. 1 - 10 micron pixel dia.) with an accompanying high pixel count (e.g. at least up to, and beyond, 104 per side within a square array). The case of absorption holograms offers an easy route to a good quality result. We can then exploit the many tricks of amplitude holography borrowed from lithographic and holographic experience using ultra-fine grain silver halide materials. The problem of exposure quantization and linearization is addressed in a pragmatic fashion. The central issue of why such holograms can tolerate intrinsic diffraction artifacts within each pixel is considered along with the exposure level quantization -- it is difficult to print individual pixels within which the optical density is clinically uniform. We cannot over-estimate the reliability difficulties that can arise in a system designed to print massive arrays of pixels in a serial fashion. The electronic testing involved has to be associated with error-free repeatability and high accompanying switching speeds. This may look easy but it is the major issue that distinguishes serially printed digital holography from the simple one-step parallel process of forming the ordinary hologram.
3-D computational method of wave loads on turret moored FPSO tankers
REN Hui-long; ZHANG Hai-bin; DAI Yu-zhi; SONG Jing-zheng
2003-01-01
A three-dimensional method of calculating wave loads of turret moored FPSO (Floating Production Storage and Offloading) tankers is presented. The linearized restoring forces acting on the ship hull by the mooring system are calculated according to the catenary theory, which are expressed as the function of linear stiffness coefficients and the displacements of the upper ends of mooring chains. The hydrodynamic coefficients of the ship are calculated by the three-dimensional potential flow theory of the linear hydrodynamic problem for ships with a low forward speed. The equations of ship motions are established with the effect of the restoring forces from the mooring system included as linear stiffness coefficients. The equations of motions are solved in frequency domain, and the responses of wave-induced motions and loads on the ship can be obtained. A computer program based on this method has been developed,and some calculation examples are illustrated. Analysis results show that the method can give satisfying prediction of wave loads.
Small-Field Measurements of 3D Polymer Gel Dosimeters through Optical Computed Tomography
Shih, Cheng-Ting; Lee, Yao-Ting; Wu, Shin-Hua; Yao, Chun-Hsu; Hsieh, Bor-Tsung
2016-01-01
With advances in therapeutic instruments and techniques, three-dimensional dose delivery has been widely used in radiotherapy. The verification of dose distribution in a small field becomes critical because of the obvious dose gradient within the field. The study investigates the dose distributions of various field sizes by using NIPAM polymer gel dosimeter. The dosimeter consists of 5% gelatin, 5% monomers, 3% cross linkers, and 5 mM THPC. After irradiation, a 24 to 96 hour delay was applied, and the gel dosimeters were read by a cone beam optical computed tomography (optical CT) scanner. The dose distributions measured by the NIPAM gel dosimeter were compared to the outputs of the treatment planning system using gamma evaluation. For the criteria of 3%/3 mm, the pass rates for 5 × 5, 3 × 3, 2 × 2, 1 × 1, and 0.5 × 0.5 cm2 were as high as 91.7%, 90.7%, 88.2%, 74.8%, and 37.3%, respectively. For the criteria of 5%/5 mm, the gamma pass rates of the 5 × 5, 3 × 3, and 2 × 2 cm2 fields were over 99%. The NIPAM gel dosimeter provides high chemical stability. With cone-beam optical CT readouts, the NIPAM polymer gel dosimeter has potential for clinical dose verification of small-field irradiation. PMID:26974434
Zhou, Jie; Yin, Lu; Zha, Kang; Li, Huirong; Liu, Zhiyuan; Wang, Jianxin; Duan, Ke; Feng, Bo
2016-03-01
Recently, construction of three-dimensional (3D) architecture and design of heterostructure have been proved to be two important approaches for improving photocatalytic (PC) properties of TiO2-based catalysts. In this work, a 3D microporous surface on Ti substrate (MPT) was prepared by simple acid etching. Then, heterojunctioned SrTiO3/TiO2 nanotubes with dominant {001} facets of anatase TiO2were successfully fabricated on MPT by combining anodization with hydrothermal treatment. The 3D microporous-patterned SrTiO3/TiO2 nanotubes heterojunction shows significantly enhanced photo-current density and ∼200% improved PC effect in degradation of Rhodamine B owing to its higher specific surface area, stronger light-harvesting ability and positive heterojunction effect in comparison with TiO2 nanotubes formed on flat Ti substrate. Moreover, the 3D microporous structure on Ti substrate improved the adhesive strength between the nanotubes layer and Ti substrate, which can be ascribed to the effective release of internal stress. Therefore, this present strategy is expected to expand the application of TiO2-based catalysts in many fields which require excellent PC properties and mechanical stability.
Efficient computational methods for electromagnetic imaging with applications to 3D magnetotellurics
Kordy, Michal Adam
The motivation for this work is the forward and inverse problem for magnetotellurics, a frequency domain electromagnetic remote-sensing geophysical method used in mineral, geothermal, and groundwater exploration. The dissertation consists of four papers. In the first paper, we prove the existence and uniqueness of a representation of any vector field in H(curl) by a vector lying in H(curl) and H(div). It allows us to represent electric or magnetic fields by another vector field, for which nodal finite element approximation may be used in the case of non-constant electromagnetic properties. With this approach, the system matrix does not become ill-posed for low-frequency. In the second paper, we consider hexahedral finite element approximation of an electric field for the magnetotelluric forward problem. The near-null space of the system matrix for low frequencies makes the numerical solution unstable in the air. We show that the proper solution may obtained by applying a correction on the null space of the curl. It is done by solving a Poisson equation using discrete Helmholtz decomposition. We parallelize the forward code on multicore workstation with large RAM. In the next paper, we use the forward code in the inversion. Regularization of the inversion is done by using the second norm of the logarithm of conductivity. The data space Gauss-Newton approach allows for significant savings in memory and computational time. We show the efficiency of the method by considering a number of synthetic inversions and we apply it to real data collected in Cascade Mountains. The last paper considers a cross-frequency interpolation of the forward response as well as the Jacobian. We consider Pade approximation through model order reduction and rational Krylov subspace. The interpolating frequencies are chosen adaptively in order to minimize the maximum error of interpolation. Two error indicator functions are compared. We prove a theorem of almost always lucky failure in the
Huerta, N. J.; Murphy, M. A.; Natarajan, V.; Weber, G.; Hamann, B.; Sumner, D. Y.
2005-12-01
Three-dimensional visualization of intricate microbial structures in rocks is essential to understand the growth of ancient microbial communities. We have imaged and reconstructed the three-dimensional morphology of 2.5-2.6 billion year old intricate microbialites preserved in carbonate using both serial sectioning and neutron computed tomography (NCT). Reconstruction techniques vary with data type and sample preservation. NCT is a non-destructive technique for imaging organic-containing samples with sufficiently high hydrogen concentrations. The resolution of reconstruction is finer than 500 microns. We reconstructed microbialites preserved as organic inclusions in calcite using NCT. Reconstructions are interpreted using volume rendering, segmentation, and an interactive Matlab/visualization environment. Visualizations demonstrate the intricacy of the structures. Noise currently limits automatic growth surface extraction, but growth of structures can be qualitatively evaluated. One of the largest obstacles to date is efficient manipulation of large data sets. Our current visualization approach always renders the supplied data set at full resolution, which requires down-sampling of datasets larger than 256 pixels3 (acquired volume data consists of up to 2048 pixels3) to isolate regions of interest and extract important features. We are exploring the use of multi-resolution techniques that store a dataset at different levels of detail and chose an appropriate resolution during user-interaction. Such an approach will allow us to visualize raw data at full resolution. Serial sectioning and scanning successive horizons provides reconstructions of samples lacking sufficient hydrogen for NCT. This technique destroys the sample and has a lower resolution than NCT. However, intricate networks of microbial laminae surrounded by cement-filled voids can be characterized using this technique. After microbial surfaces are manually interpreted on slices, the images lack noise
Lao, Zhaoxin; Hu, Yanlei; Zhang, Chenchu; Yang, Liang; Li, Jiawen; Chu, Jiaru; Wu, Dong
2015-12-22
The hierarchical structures are the derivation of various functionalities in the natural world and have inspired broad practical applications in chemical systhesis and biological manipulation. However, traditional top-down fabrication approaches suffered from low complexity. We propose a laser printing capillary-assisted self-assembly (LPCS) strategy for fabricating regular periodic structures. Microscale pillars are first produced by the localized femtosecond laser polymerization and are subsequently self-assembled into periodic hierarchical architectures with the assistance of controlled capillary force. Moreover, based on anisotropic assemblies of micropillars, the LPCS method is further developed for the preparation of more complicated and advanced functional microstructures. Pillars cross section, height, and spatial arrangement can be tuned to guide capillary force, and diverse assemblies with different configurations are thus achieved. Finally, we developed a strategy for growing micro/nanoparticles in designed spatial locations through solution-evaporation self-assembly induced by morphology. Due to the high flexibility of LPCS method, the special arrangements, sizes, and distribution density of the micro/nanoparticles can be controlled readily. Our method will be employed not only to fabricate anisotropic hierarchical structures but also to design and manufacture organic/inorganic microparticles. PMID:26506428
Computational Tools for Evaluating Phylogenetic and Hierarchical Clustering Trees
Chakerian, John; Holmes, Susan
2010-01-01
Inferential summaries of tree estimates are useful in the setting of evolutionary biology, where phylogenetic trees have been built from DNA data since the 1960's. In bioinformatics, psychometrics and data mining, hierarchical clustering techniques output the same mathematical objects, and practitioners have similar questions about the stability and `generalizability' of these summaries. This paper provides an implementation of the geometric distance between trees developed by Billera, Holmes...
In dynamic computer-generated holography that utilizes spatial light modulators, both hologram synthesis and hologram representation are essential in terms of fast computation and high reconstruction quality. For hologram synthesis, i.e. the computation step, Fresnel transform based or point-source based raytracing methods can be applied. In the encoding step, the complex wave-field has to be optimally represented by the SLM with its given modulation capability. For proper hologram reconstruction that implies a simultaneous and independent amplitude and phase modulation of the input wave-field by the SLM. In this paper, we discuss full complex hologram representation methods on SLMs by considering inherent SLM parameter such as modulation type and bit depth on their reconstruction performance such as diffraction efficiency and SNR. We review the three implementation schemes of Burckhardt amplitude-only representation, phase-only macro-pixel representation, and two-phase interference representation. Besides the optical performance we address their hardware complexity and required computational load. Finally, we experimentally demonstrate holographic reconstructions of different representation schemes as obtained by functional prototypes utilizing SeeReal's viewing-window holographic display technology. The proposed hardware implementations enable a fast encoding of complex-valued hologram data and thus will pave the way for commercial real-time holographic 3D imaging in the near future.
Reichelt, Stephan; Leister, Norbert
2013-02-01
In dynamic computer-generated holography that utilizes spatial light modulators, both hologram synthesis and hologram representation are essential in terms of fast computation and high reconstruction quality. For hologram synthesis, i.e. the computation step, Fresnel transform based or point-source based raytracing methods can be applied. In the encoding step, the complex wave-field has to be optimally represented by the SLM with its given modulation capability. For proper hologram reconstruction that implies a simultaneous and independent amplitude and phase modulation of the input wave-field by the SLM. In this paper, we discuss full complex hologram representation methods on SLMs by considering inherent SLM parameter such as modulation type and bit depth on their reconstruction performance such as diffraction efficiency and SNR. We review the three implementation schemes of Burckhardt amplitude-only representation, phase-only macro-pixel representation, and two-phase interference representation. Besides the optical performance we address their hardware complexity and required computational load. Finally, we experimentally demonstrate holographic reconstructions of different representation schemes as obtained by functional prototypes utilizing SeeReal's viewing-window holographic display technology. The proposed hardware implementations enable a fast encoding of complex-valued hologram data and thus will pave the way for commercial real-time holographic 3D imaging in the near future.
This study presents the pore-space system analysis of the 2-ITAB-1-RJ well cores, which were drilled in the Sao Jose do Itaborai Basin, in the state of Rio de Janeiro, Brasil. The analysis presented herein has been developed based on two techniques: nuclear logging and 3D high-resolution X-ray computed microtomography. Nuclear logging has been proven to be the technique that provides better quality and more quantitative information about the porosity using radioactive sources. The Density Gamma Probe and the Neutron Sonde used in this work provide qualitative information about bulk density variations and compensated porosity of the geological formation. The samples obtained from the well cores were analyzed by microtomography. The use of this technique in sedimentary rocks allows quantitative evaluation of pore system and generates high-resolution 3D images (∼microns order). The images and data obtained by microtomography were integrated with the response obtained by nuclear logging. The results obtained by these two techniques allow the understanding of the pore-size distribution and connectivity, as well as the porosity values. Both techniques are important and they complement each other.
The storage capacity and production of oil are influenced, among other things, by rocks and fluids characteristics. Porosity is one of the most important characteristics to be analyzed in oil industry, mainly in oil prospection because it represents the direct capacity of storage fluids in the rocks. By definition, porosity is the ratio of pore volume to the total bulk volume of the formation, expressed in percentage, being able to be absolute or effective. The aim of this study was to calculate porosity by 3D High-Resolution X-ray Computed Microtomography using core plugs from Resende Formation which were collected in Porto Real, Rio de Janeiro State. This formation is characterized by sandstones and fine conglomerates with associated fine siliciclastic sediments, and the paleoenviroment is interpreted as a braided fluvial system. For acquisitions data, it was used a 3D high resolution microtomography system which has a microfocus X-ray tube (spot size < 5μm) and a 12-bit cooled X-ray camera (CCD fiber-optically coupled to a scintillator) operated at 100 kV and 100 μA. Twenty-two samples taken at different depths from two boreholes were analyzed. A total of 961 slices were performed with a resolution of 14.9 μm. The results demonstrated that μ-CT is a reliable and effective technique. Through the images and data it was possible to quantify the porosity and to view the size and shape of porous. (author)
Boiling water flows. A local wall heat transfer model for use in an Eulerian 3-D computer code
Electricite de France is currently developing a 3-D computer code for the Eulerian simulation of two-phase flows. This code, named ASTRID, is based on the six-equation two-fluid model. Boiling water flows are among the main applications of ASTRID, especially for nuclear power plant design. In order to provide ASTRID with appropriate closure laws and boundary conditions, Electricite de France and the Institut de Mecanique des Fluides de Toulouse (IMFT) have collaborated since 1991. The analysis of the current knowledge made possible to build a first set of closure laws and boundary conditions for boiling water flows, suitable for ASTRID. This paper is focused on the model used for heat transfer and bubble production at the wall, in a convective boiling situation. This model has been tested for a first comparison with existing experimental data. The results of this comparison are also presented here. (authors). 5 figs., 9 refs
Steady-State VEP-Based Brain-Computer Interface Control in an Immersive 3D Gaming Environment
Burke R
2005-01-01
Full Text Available This paper presents the application of an effective EEG-based brain-computer interface design for binary control in a visually elaborate immersive 3D game. The BCI uses the steady-state visual evoked potential (SSVEP generated in response to phase-reversing checkerboard patterns. Two power-spectrum estimation methods were employed for feature extraction in a series of offline classification tests. Both methods were also implemented during real-time game play. The performance of the BCI was found to be robust to distracting visual stimulation in the game and relatively consistent across six subjects, with 41 of 48 games successfully completed. For the best performing feature extraction method, the average real-time control accuracy across subjects was 89%. The feasibility of obtaining reliable control in such a visually rich environment using SSVEPs is thus demonstrated and the impact of this result is discussed.
A spherical harmonics research code (DANTE) has been developed which is compatible with parallel computer architectures. DANTE provides 3-D, multi-material, deterministic, transport capabilities using an arbitrary finite element mesh. The linearized Boltzmann transport equation is solved in a second order self-adjoint form utilizing a Galerkin finite element spatial differencing scheme. The core solver utilizes a preconditioned conjugate gradient algorithm. Other distinguishing features of the code include options for discrete-ordinates and simplified spherical harmonics angular differencing, an exact Marshak boundary treatment for arbitrarily oriented boundary faces, in-line matrix construction techniques to minimize memory consumption, and an effective diffusion based preconditioner for scattering dominated problems. Algorithm efficiency is demonstrated for a massively parallel SIMD architecture (CM-5), and compatibility with MPP multiprocessor platforms or workstation clusters is anticipated
Lithium-air battery has attracted extensively attention and now developing catalysts with high electrocatalytic activity is one of the challenges for lithium-air battery. In this paper, 3D hierarchical porous spinel CoFe2O4 hollow nanospheres were first prepared by a facile hydrothermal method. The hollow CoFe2O4 nanospheres have unique bimodal porous structure which consists of micropores and mesopores. The catalytic activity of the CoFe2O4 hollow nanospheres for oxygen reduction reaction (ORR) has been studied and compared with the acetylene black, the solid CoFe2O4 nanospheres and the commercial Pt/C by using rotating ring-disk electrode (RRDE) technique. The spinel CoFe2O4 hollow nanospheres exhibit superior catalytic activity for the ORR compared to the acetylene black and the solid CoFe2O4 nanospheres. Besides, the spinel CoFe2O4 hollow nanospheres also afford high catalytic activity for the oxygen evolution reaction (OER). Furthermore, the hollow CoFe2O4 nanospheres show the smallest overpotential between ORR and OER. The chronoamperometric studies show that the CoFe2O4 hollow nanospheres exhibit excellent stability for both the ORR and OER. The high ORR and OER activities and stabilities of CoFe2O4 hollow nanospheres could be attributed to their special 3D hierarchical porous structure. This material shows a significant potential application on lithium-air battery
Nourian, Pirouz; Gonçalves, Romulo; Zlatanova, Sisi; Ohori, Ken Arroyo; Vu Vo, Anh
2016-01-01
Voxel representations have been used for years in scientific computation and medical imaging. The main focus of our research is to provide easy access to methods for making large-scale voxel models of built environment for environmental modelling studies while ensuring they are spatially correct, meaning they correctly represent topological and semantic relations among objects. In this article, we present algorithms that generate voxels (volumetric pixels) out of point cloud, curve, or surface objects. The algorithms for voxelization of surfaces and curves are a customization of the topological voxelization approach [1]; we additionally provide an extension of this method for voxelization of point clouds. The developed software has the following advantages:•It provides easy management of connectivity levels in the resulting voxels.•It is not dependant on any external library except for primitive types and constructs; therefore, it is easy to integrate them in any application.•One of the algorithms is implemented in C++ and C for platform independence and efficiency. PMID:27408832
Fazzolari, Fiorenzo A.; Carrera, Erasmo
2014-02-01
In this paper, the Ritz minimum energy method, based on the use of the Principle of Virtual Displacements (PVD), is combined with refined Equivalent Single Layer (ESL) and Zig Zag (ZZ) shell models hierarchically generated by exploiting the use of Carrera's Unified Formulation (CUF), in order to engender the Hierarchical Trigonometric Ritz Formulation (HTRF). The HTRF is then employed to carry out the free vibration analysis of doubly curved shallow and deep functionally graded material (FGM) shells. The PVD is further used in conjunction with the Gauss theorem to derive the governing differential equations and related natural boundary conditions. Donnell-Mushtari's shallow shell-type equations are given as a particular case. Doubly curved FGM shells and doubly curved sandwich shells made up of isotropic face sheets and FGM core are investigated. The proposed shell models are widely assessed by comparison with the literature results. Two benchmarks are provided and the effects of significant parameters such as stacking sequence, boundary conditions, length-to-thickness ratio, radius-to-length ratio and volume fraction index on the circular frequency parameters and modal displacements are discussed.
Wang, Ya; Lin, Li; Li, Fang; Chen, Liang; Chen, Donghui; Yang, Chongyang; Huang, Manhong
2016-05-11
A BiOI/BiOBr composite was successfully fabricated by a simple hydrothermal method. The composite was characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). The BiOI/BiOBr composite exhibited enhanced photocatalytic bacteriostatic activity towards E. coli compared to the pure BiOI or BiOBr under visible light irradiation. The enhanced photocatalytic performance can be attributed to the improved separation efficiency of the photogenerated holes because of its heterojunction structure. In addition, the possible bacteriostatic mechanism of the BiOI/BiOBr composite under visible light irradiation is discussed. The hierarchical microsphere BiOI/BiOBr showed enhanced photocatalytic bacteriostasis towards Escherichia coli under visible light. PMID:27105324
Roberto Rinaldi
2014-12-01
Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.
Exact Computation of the Topology and Geometric Invariants of the Voronòi Diagram of Spheres in 3D
Fran(c)ois Anton; Darka Mioc; Marcelo Santos
2013-01-01
In this paper,we are addressing the exact computation of the Delaunay graph (or quasi-triangulation) and the Voronoi diagram of spheres using Wu's algorithm.Our main contributions are first a methodology for automated derivation of invariants of the Delaunay empty circumsphere predicate for spheres and the Voronoi vertex of four spheres,then the application of this methodology to get all geometrical invariants that intervene in this problem and the exact computation of the Delaunay graph and the Voronoi diagram of spheres.To the best of our knowledge,there does not exist a comprehensive treatment of the exact computation with geometrical invariants of the Delaunay graph and the Voronoi diagram of spheres.Starting from the system of equations defining the zero-dimensional algebraic set of the problem,we are applying Wu's algorithm to transform the initial system into an equivalent Wu characteristic (triangular) set.In the corresponding system of algebraic equations,in each polynomial (except the first one),the variable with higher order from the preceding polynomial has been eliminated (by pseudo-remainder computations) and the last polynomial we obtain is a polynomial of a single variable.By regrouping all the formal coefficients for each monomial in each polynomial,we get polynomials that are invariants for the given problem.We rewrite the original system by replacing the invariant polynomials by new formal coefficients.We repeat the process until all the algebraic relationships (syzygies) between the invariants have been found by applying Wu's algorithm on the invariants.Finally,we present an incremental algorithm for the construction of Voronoi diagrams and Delaunay graphs of spheres in 3D and its application to Geodesy.
Jadhav, Harsharaj S; Pawar, Sambhaji M; Jadhav, Arvind H; Thorat, Gaurav M; Seo, Jeong Gil
2016-01-01
Ternary spinel CuCo2O4 nanostructure clenches great potential as high-performance electrode material for next-generation energy storage systems because of its higher electrical conductivity and electrochemical activity. Carbon free and binder free 3D flower-like CuCo2O4 structure are grown on nickel foam (NF) via a facile hydrothermal synthesis method followed by annealing. The obtained CuCo2O4/NF is directly used as electrode for lithium ion batteries (LIBs) and supercapacitors (SCs) application. The electrochemical study of 3D flower-like CuCo2O4 as an electrode for LIB and SC shows highly mesoporous unique architecture plays important role in achieving high capacity/capacitance with superior cycle life. The high surface area and mesoporous nature not only offer sufficient reaction sites, but also can accelerate the liquid electrolyte to penetrate electrode and the ions to reach the reacting sites. In outcome, it exhibits highest capacity of 1160 mA h g(-1) after 200 cycles when used as an anode for LIB and specific capacitance of 1002 F g(-1) after 3000 cycles. The superior electrochemical of synthesized material is attributed to direct contact of electrode active material with good intrinsic electrical conductivity to the underneath conductive NF substrate builds up an express path for fast ion and electron transfer. PMID:27506839
Jadhav, Harsharaj S.; Pawar, Sambhaji M.; Jadhav, Arvind H.; Thorat, Gaurav M.; Seo, Jeong Gil
2016-08-01
Ternary spinel CuCo2O4 nanostructure clenches great potential as high-performance electrode material for next-generation energy storage systems because of its higher electrical conductivity and electrochemical activity. Carbon free and binder free 3D flower-like CuCo2O4 structure are grown on nickel foam (NF) via a facile hydrothermal synthesis method followed by annealing. The obtained CuCo2O4/NF is directly used as electrode for lithium ion batteries (LIBs) and supercapacitors (SCs) application. The electrochemical study of 3D flower-like CuCo2O4 as an electrode for LIB and SC shows highly mesoporous unique architecture plays important role in achieving high capacity/capacitance with superior cycle life. The high surface area and mesoporous nature not only offer sufficient reaction sites, but also can accelerate the liquid electrolyte to penetrate electrode and the ions to reach the reacting sites. In outcome, it exhibits highest capacity of 1160 mA h g‑1 after 200 cycles when used as an anode for LIB and specific capacitance of 1002 F g‑1 after 3000 cycles. The superior electrochemical of synthesized material is attributed to direct contact of electrode active material with good intrinsic electrical conductivity to the underneath conductive NF substrate builds up an express path for fast ion and electron transfer.
Jadhav, Harsharaj S.; Pawar, Sambhaji M.; Jadhav, Arvind H.; Thorat, Gaurav M.; Seo, Jeong Gil
2016-01-01
Ternary spinel CuCo2O4 nanostructure clenches great potential as high-performance electrode material for next-generation energy storage systems because of its higher electrical conductivity and electrochemical activity. Carbon free and binder free 3D flower-like CuCo2O4 structure are grown on nickel foam (NF) via a facile hydrothermal synthesis method followed by annealing. The obtained CuCo2O4/NF is directly used as electrode for lithium ion batteries (LIBs) and supercapacitors (SCs) application. The electrochemical study of 3D flower-like CuCo2O4 as an electrode for LIB and SC shows highly mesoporous unique architecture plays important role in achieving high capacity/capacitance with superior cycle life. The high surface area and mesoporous nature not only offer sufficient reaction sites, but also can accelerate the liquid electrolyte to penetrate electrode and the ions to reach the reacting sites. In outcome, it exhibits highest capacity of 1160 mA h g−1 after 200 cycles when used as an anode for LIB and specific capacitance of 1002 F g−1 after 3000 cycles. The superior electrochemical of synthesized material is attributed to direct contact of electrode active material with good intrinsic electrical conductivity to the underneath conductive NF substrate builds up an express path for fast ion and electron transfer. PMID:27506839
Koniges Alice
2013-11-01
Full Text Available The Neutralized Drift Compression Experiment II (NDCX II is an induction accelerator planned for initial commissioning in 2012. The final design calls for a 3 MeV, Li+ ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and transverse dimension of order 1 mm. The NDCX II will be used in studies of material in the warm dense matter (WDM regime, and ion beam/hydrodynamic coupling experiments relevant to heavy ion based inertial fusion energy. We discuss recent efforts to adapt the 3D ALE-AMR code to model WDM experiments on NDCX II. The code, which combines Arbitrary Lagrangian Eulerian (ALE hydrodynamics with Adaptive Mesh Refinement (AMR, has physics models that include ion deposition, radiation hydrodynamics, thermal diffusion, anisotropic material strength with material time history, and advanced models for fragmentation. Experiments at NDCX-II will explore the process of bubble and droplet formation (two-phase expansion of superheated metal solids using ion beams. Experiments at higher temperatures will explore equation of state and heavy ion fusion beam-to-target energy coupling efficiency. Ion beams allow precise control of local beam energy deposition providing uniform volumetric heating on a timescale shorter than that of hydrodynamic expansion. We also briefly discuss the effects of the move to exascale computing and related computational changes on general modeling codes in fusion.
Siham Hairoud
2013-01-01
Full Text Available In order to better assess the behaviours of the propagation channel in a confined environment such as a railway tunnel for subway application, we present an optimization method for a deterministic channel simulator based on 3D ray tracing associated to the geometrical optics laws and the uniform theory of diffraction. This tool requires a detailed description of the environment. Thus, the complexity of this model is directly bound to the complexity of the environment and specifically to the number of facets that compose it. In this paper, we propose an algorithm to identify facets that have no significant impact on the wave propagation. This allows us to simplify the description of the geometry of the modelled environment by removing them and by this way, to reduce the complexity of our model and therefore its computation time. A comparative study between full and simplified environment is led and shows the impact of this proposed method on the characteristic parameters of the propagation channel. Thus computation time obtained from the simplified environment is 6 times lower than the one of the full model without significant degradation of simulation accuracy.
Visualization of hierarchically structured information for human-computer interaction
Cheon, Suh Hyun; Lee, J. K.; Choi, I. K.; Kye, S. C.; Lee, N. K. [Dongguk University, Seoul (Korea)
2001-11-01
Visualization techniques can be used to support operator's information navigation tasks on the system especially consisting of an enormous volume of information, such as operating information display system and computerized operating procedure system in advanced control room of nuclear power plants. By offering an easy understanding environment of hierarchically structured information, these techniques can reduce the operator's supplementary navigation task load. As a result of that, operators can pay more attention on the primary tasks and ultimately improve the cognitive task performance. In this report, an interface was designed and implemented using hyperbolic visualization technique, which is expected to be applied as a means of optimizing operator's information navigation tasks. 15 refs., 19 figs., 32 tabs. (Author)
Paparcone, Raffaella; Kniep, Rüdiger; Brickmann, Jürgen
2009-04-01
The shape development of a biomimetic fluorapatite-gelatine nanocomposite on the mum scale is characterised by a fractal mechanism with the origin being intrinsically coded in a (central) elongated hexagonal-prismatic seed. The 3D superstructure of the seed is distinctively overlaid by a pattern consisting of gelatine microfibrils. The orientation of the microfibrils is assumed to be controlled by an intrinsic electrical field generated by the nanocomposite during development and growth of the seed. In order to confirm this assumption and to get more detailed information on orientational relations of the complex nanocomposite we simulated the pattern formation process up to the microm scale. The results from experimental studies and simulation results on an atomistic level support a model scenario wherein the elementary building blocks for the aggregation are represented by elongated hexagonal-prismatic objects (A-units), with the embedded collagen triple-helices in their centers. The interactions of the A-units are consequently modelled by three contributions: the crystal energy part (originating from the pair-wise interactions of the "apatite shells" of the prismatic units), the electrostatic interaction (originating from the unit charges located at the ends of the collagen triple helices), and the interaction energy of the A-units mediated by the solvent. The next level of complexity is related to the fact that micro fibrils were found in the fluorapatite-gelatine nanocomposites. They consist of bundles of triple helical protein molecules, which are embedded within the 3D-hexagonal prismatic arrangement of the A-units. In our approach we consider the microfibrils as chains of flexible dipoles with effective dipole moments. The crystal growth processes is modelled as an energetically controlled stepwise association of elementary building blocks of different kind on a 3D-grid. The remarkable and excellent qualitative agreement between the simulated fibril patterns
Davis, A. B.; Cahalan, R. F.
2001-05-01
The Intercomparison of 3D Radiation Codes (I3RC) is an on-going initiative involving an international group of over 30 researchers engaged in the numerical modeling of three-dimensional radiative transfer as applied to clouds. Because of their strong variability and extreme opacity, clouds are indeed a major source of uncertainty in the Earth's local radiation budget (at GCM grid scales). Also 3D effects (at satellite pixel scales) invalidate the standard plane-parallel assumption made in the routine of cloud-property remote sensing at NASA and NOAA. Accordingly, the test-cases used in I3RC are based on inputs and outputs which relate to cloud effects in atmospheric heating rates and in real-world remote sensing geometries. The main objectives of I3RC are to (1) enable participants to improve their models, (2) publish results as a community, (3) archive source code, and (4) educate. We will survey the status of I3RC and its plans for the near future with a special emphasis on the mathematical models and computational approaches. We will also describe some of the prime applications of I3RC's efforts in climate models, cloud-resolving models, and remote-sensing observations of clouds, or that of the surface in their presence. In all these application areas, computational efficiency is the main concern and not accuracy. One of I3RC's main goals is to document the performance of as wide a variety as possible of three-dimensional radiative transfer models for a small but representative number of ``cases.'' However, it is dominated by modelers working at the level of linear transport theory (i.e., they solve the radiative transfer equation) and an overwhelming majority of these participants use slow-but-robust Monte Carlo techniques. This means that only a small portion of the efficiency vs. accuracy vs. flexibility domain is currently populated by I3RC participants. To balance this natural clustering the present authors have organized a systematic outreach towards
Koldan, Jelena
2013-01-01
The growing significance, technical development and employment of electromagnetic (EM) methods in exploration geophysics have led to the increasing need for reliable and fast techniques of interpretation of 3-D EM data sets acquired in complex geological environments. The first and most important step to creating an inversion method is the development of a solver for the forward problem. In order to create an efficient, reliable and practical 3-D EM inversion, it is necessary to have a 3-D EM...
Thomsen, Jesper Skovhus; Laib, A.; Koller, B.; Prohaska, S.; Mosekilde, Li.; Gowin, W.
2005-01-01
Stereology applied on histological sections is the 'gold standard' for obtaining quantitative information on cancellous bone structure. Recent advances in micro computed tomography (microCT) have made it possible to acquire three-dimensional (3D) data non-destructively. However, before the 3D...... methods can be used as a substitute for the current 'gold standard' they have to be verified against the existing standard. The aim of this study was to compare bone structural measures obtained from 3D microCT data sets with those obtained by stereology performed on conventional histological sections...... tibial metaphysis. The biopsies were embedded in methylmetacrylate before microCT scanning in a Scanco microCT 40 scanner at a resolution of 20 x 20 x 20 microm3, and the 3D data sets were analysed with a computer program. After microCT scanning, 16 sections were cut from the central 2 mm of each biopsy...
Li, T; Li, G H; Li, L H; Liu, L; Xu, Y; Ding, H Y; Zhang, T
2016-02-01
In this study, a facile and inexpensive and self-assembled strategy to massively fabricate Ni/Co layered double hydroxides (LDHs) is developed under mild reaction conditions (55 °C). The resulting composite material displays a special three-dimensional hierarchical microsphere structure with well-defined flower-like configuration. The fabrication mechanism can be ascribed to stepwise and regular reaction process of nanoparticles and nanosheets gradually growing to nanopetals and then assembling into flower-like microspheres, based on the systematically investigation of various reaction factors including the Ni:Co feeding ratio, the reaction time and the initial pH-value. Because of its large surface, ultrathin feature and synergetic results of this Ni/Co LDHs nanosheets (20 nm), these Ni/Co-LDHs microspheres deliver an excellent capacitance value about 2228 F·g(-1) (1 A·g(-1)). An all-solid-state flexible asymmetric supercapacitor is designed and assembled by exploiting this Ni/Co-LDHs as the positive materials, which exhibits energy density of 165.51 Wh·kg(1-) at 1.53 KW·kg(1-). It may have vast potential significance in personal wearable equipment. Moreover, this monolithic design provides a promising approach for large scale fabrication of other LDHs materials. PMID:26751174
Wilbert A. McClay
2015-09-01
Full Text Available Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user’s intent for specific keyboard strikes or mouse button presses. The BCI’s data analytics OPEN ACCESS Brain. Sci. 2015, 5 420 of a subject’s MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse.
McClay, Wilbert A; Yadav, Nancy; Ozbek, Yusuf; Haas, Andy; Attias, Hagaii T; Nagarajan, Srikantan S
2015-01-01
Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI) for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG) brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user's intent for specific keyboard strikes or mouse button presses. The BCI's data analytics OPEN ACCESS Brain. Sci. 2015, 5 420 of a subject's MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse. PMID:26437432
McClay, Wilbert A.; Yadav, Nancy; Ozbek, Yusuf; Haas, Andy; Attias, Hagaii T.; Nagarajan, Srikantan S.
2015-01-01
Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI) for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG) brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user’s intent for specific keyboard strikes or mouse button presses. The BCI’s data analytics of a subject’s MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse. PMID:26437432
Arrigoni, Chiara; Bongio, Matilde; Talò, Giuseppe; Bersini, Simone; Enomoto, Junko; Fukuda, Junji; Moretti, Matteo
2016-07-01
A major challenge in the development of clinically relevant 3D tissue constructs is the formation of vascular networks for oxygenation, nutrient supply, and waste removal. To this end, this study implements a multimodal approach for the promotion of vessel-like structures formation in stiff fibrin hydrogels. Computational simulations have been performed to identify the easiest microchanneled configuration assuring normoxic conditions throughout thick cylindrical hydrogels (8 mm height, 6 mm ∅), showing that in our configuration a minimum of three microchannels (600 μm ∅), placed in a non-planar disposition, is required. Using small hydrogel bricks with oxygen distribution equal to the microchanneled configuration, this study demonstrates that among different culture conditions, co-culture of mesenchymal and endothelial cells supplemented with ANG-1 and VEGF leads to the most developed vascular network. Microchanneled hydrogels have been then cultured in the same conditions both statically and in a bioreactor for 7 d. Unexpectedly, the combination between shear forces and normoxic conditions is unable to promote microvascular networks formation in three-channeled hydrogels. Differently, application of either shear forces or normoxic conditions alone results in microvessels outgrowth. These results suggest that to induce angiogenesis in engineered constructs, complex interactions between several biochemical and biophysical parameters have to be modulated. PMID:27191352
Tang, Li; Kwon, Young H.; Alward, Wallace L. M.; Greenlee, Emily C.; Lee, Kyungmoo; Garvin, Mona K.; Abràmoff, Michael D.
2010-03-01
The shape of the optic nerve head (ONH) is reconstructed automatically using stereo fundus color images by a robust stereo matching algorithm, which is needed for a quantitative estimate of the amount of nerve fiber loss for patients with glaucoma. Compared to natural scene stereo, fundus images are noisy because of the limits on illumination conditions and imperfections of the optics of the eye, posing challenges to conventional stereo matching approaches. In this paper, multi scale pixel feature vectors which are robust to noise are formulated using a combination of both pixel intensity and gradient features in scale space. Feature vectors associated with potential correspondences are compared with a disparity based matching score. The deep structures of the optic disc are reconstructed with a stack of disparity estimates in scale space. Optical coherence tomography (OCT) data was collected at the same time, and depth information from 3D segmentation was registered with the stereo fundus images to provide the ground truth for performance evaluation. In experiments, the proposed algorithm produces estimates for the shape of the ONH that are close to the OCT based shape, and it shows great potential to help computer-aided diagnosis of glaucoma and other related retinal diseases.
Skála, J.; Baruffa, F.; Büchner, J.; Rampp, M.
2015-08-01
Context. The numerical simulation of turbulence and flows in almost ideal astrophysical plasmas with large Reynolds numbers motivates the implementation of magnetohydrodynamical (MHD) computer codes with low resistivity. They need to be computationally efficient and scale well with large numbers of CPU cores, allow obtaining a high grid resolution over large simulation domains, and be easily and modularly extensible, for instance, to new initial and boundary conditions. Aims: Our aims are the implementation, optimization, and verification of a computationally efficient, highly scalable, and easily extensible low-dissipative MHD simulation code for the numerical investigation of the dynamics of astrophysical plasmas with large Reynolds numbers in three dimensions (3D). Methods: The new GOEMHD3 code discretizes the ideal part of the MHD equations using a fast and efficient leap-frog scheme that is second-order accurate in space and time and whose initial and boundary conditions can easily be modified. For the investigation of diffusive and dissipative processes the corresponding terms are discretized by a DuFort-Frankel scheme. To always fulfill the Courant-Friedrichs-Lewy stability criterion, the time step of the code is adapted dynamically. Numerically induced local oscillations are suppressed by explicit, externally controlled diffusion terms. Non-equidistant grids are implemented, which enhance the spatial resolution, where needed. GOEMHD3 is parallelized based on the hybrid MPI-OpenMP programing paradigm, adopting a standard two-dimensional domain-decomposition approach. Results: The ideal part of the equation solver is verified by performing numerical tests of the evolution of the well-understood Kelvin-Helmholtz instability and of Orszag-Tang vortices. The accuracy of solving the (resistive) induction equation is tested by simulating the decay of a cylindrical current column. Furthermore, we show that the computational performance of the code scales very
Shih, T. I.-P.; Bailey, R. T.; Nguyen, H. L.; Roelke, R. J.
1990-01-01
An efficient computer program, called GRID2D/3D was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no
Sasdelli Neto, Roberto; Nomura, Cesar Higa; Macedo, Ana Carolina Sandoval; Bianco, Danilo Perussi; Kay, Fernando Uliana; Szarf, Gilberto; Teles, Gustavo Borges da Silva; Shoji, Hamilton; Santana Netto, Pedro Vieira; Passos, Rodrigo Bastos Duarte; Chate, Rodrigo Caruso; Ishikawa, Walther Yoshiharu; Lima, Joao Paulo Bacellar Costa; Rocha, Marcelo Assis; Marcos, Vinicius Neves; Funari, Marcelo Buarque de Gusmao, E-mail: roberto.neto@einstein.br [Hospital Israelita Albert Einstein, Sao Paulo, SP (Brazil); Failla, Bruna Bonaventura [Universidade Metodista de Sao Paulo, Sao Bernardo do Campo, SP (Brazil)
2013-07-01
Coronary computed tomography angiography (coronary CTA) is a powerful non-invasive imaging method to evaluate coronary artery disease. Nowadays, coronary CTA estimated effective radiation dose can be dramatically reduced using state-of-the-art scanners, such as 320-row detector CT (320-CT), without changing coronary CTA diagnostic accuracy. To optimize and further reduce the radiation dose, new iterative reconstruction algorithms were released recently by several CT manufacturers, and now they are used routinely in coronary CTA. This paper presents our first experience using coronary CTA with 320-CT and the Adaptive Iterative Dose Reduction 3D (AIDR-3D). In addition, we describe the current indications for coronary CTA in our practice as well as the acquisition standard protocols and protocols related to CT application for radiation dose reduction. In conclusion, coronary CTA radiation dose can be dramatically reduced following the 'as low as reasonable achievable' principle by combination of exam indication and well-documented technics for radiation dose reduction, such as beta blockers, low-kV, and also the newest iterative dose reduction software as AIDR-3D. (author)
F. Rezanezhad
2009-05-01
Full Text Available The hydraulic conductivity of unsaturated peat soils is controlled by the peat structure which affects the air-filled porosity, pore size distribution and shape. This study investigates how the size and shape of pores affects the flow of water through peat soils. In this study we used X-ray Computed Tomography (CT, at 45 µm resolution under 5 specific soil-water pressure head levels to provide 3-D, high-resolution images that were used to detect the inner pore structure of peat samples under a changing water regime. Pore structure and configuration were found to be irregular, which affected the rate of water transmission through peat soils. The 3-D analysis suggested that pore distribution is dominated by a single large pore-space. At low pressure head, this single large air-filled pore imparted a more effective flowpath compared to smaller pores. Smaller pores were disconnected and the flowpath was more tortuous than in the single large air-filled pore, and their contribution to flow was negligible when the single large pore was active. We quantify the pore structure of peat soil that affects the hydraulic conductivity in the unsaturated condition, and demonstrate the validity of our estimation of peat unsaturated hydraulic conductivity by making a comparison with a standard permeameter-based method. Estimates of unsaturated hydraulic conductivities were made for the purpose of testing the sensitivity of pore shape and geometry parameters on the hydraulic properties of peats and how to evaluate the structure of the peat and its affects on parameterization. We also studied the ability to quantify these factors for different soil moisture contents in order to define how the factors controlling the shape coefficient vary with changes in soil water pressure head. The relation between measured and estimated unsaturated hydraulic conductivity at various heads shows that rapid initial drainage, that changes the air-filled pore properties, creates a
Parallelization of hierarchical radiosity algorithms on distributed memory computers
Şireli, Ahmet Reşat
1998-01-01
Ankara : Department of Computer Engineering and Information Science and the Institute of Engineering and Science of Bilkent Univ., 1998. Thesis (Master's) -- Bilkent University, 1998. Includes bibliographical references leaves 93-97. Şireli, Ahmet Reşat Master's
Tarplee, Mark F. V.; van der Meer, Jaap J. M.; Davis, Graham R.
2011-11-01
X-ray computed microtomography (μCT), a non-destructive analytical technique, was used to create volumetric three-dimensional (3D) models representing the internal composition and structure of undisturbed pro- and subglacial soft sediment sample plugs for the purposes of identifying and analysing kinematic indicators. The technique is introduced and a methodology is presented addressing specific issues relating to the investigation of unlithified, polymineralic sediments. Six samples were selected based on their proximity to 'type' brittle and ductile deformation structures, or because of their perceived suitability for successful application of the technique. Analysis of a proglacial 'ideal' specimen permitted the 3D geometry of a suite of micro-faults and folds to be investigated and the strain history of the sample reconstructed. The poor contrast achieved in scanning a diamicton of glaciomarine origin is attributable to overconsolidation under normal loading, the sediment demonstrated to have undergone subsequent subglacial deformation. Another overconsolidated diamicton contains an extensive, small scale (scale. A volcanic lithic clast contrasts well with the surrounding matrix in a 'lodgement' till sample containing μCT (void) and thin-section evidence of clast ploughing. Initial ductile deformation was followed by dewatering of the matrix, which led to brittle failure and subsequent emplacement. Compelling evidence of clast rotation is located in the top of another sample, μCT analysis revealing that the grain has a proximal décollement surface orientated parallel to the plane of shear. The lenticular morphology of the rotational structure defined suggests an unequal distribution of forces along two of the principal stress axes. The excellent contrast between erratics contained within a sample and the enclosing till highlight the considerable potential of the technique in permitting the rapid (semi-)quantitative analysis of large datasets. The subglacial
Nishio, Gunji; Watanabe, Kouji; Murazaki, Minoru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yamazaki, Noboru; Kouno, Kouji
1998-11-01
The CELVA-3D computer code was developed to evaluate thermofluid phenomena and transport behavior of radioactive materials in a cell during hypothetical explosion in the fuel reprocessing plant. The code calculates temperature, pressure, flow velocity in the cell by three-dimensional thermofluid analysis and calculated an ability to confine the radioactive materials by transport analysis taking into consideration the thermofluid in the cell. And the CELVA-3D is separated into CELVA-3D(M) for a deflagration analysis and CELVA-3D(R) for a detonation analysis; the numerical solution of CELVA-3D(M) for the deflagration was applied to SIMPLE and SIMPLEST for a semi-implicit method, and the solution of CELVA-3D(R) for the detonation by ICE for an explicit method. The mathematical models in CELVA-3D were verified by comparison of code calculations with the results of JAERI`s demonstration tests simulating hypothetical explosion in the reprocessing plant. (author)
Liang Xin, E-mail: Xin.Liang@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); College of Stomatology, Dalian Medical University (China); Lambrichts, Ivo, E-mail: Ivo.Lambrichts@uhasselt.b [Department of Basic Medical Sciences, Histology and Electron Microscopy, Faculty of Medicine, University of Hasselt, Diepenbeek (Belgium); Sun Yi, E-mail: Sunyihello@hotmail.co [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Denis, Kathleen, E-mail: kathleen.denis@groept.b [Department of Industrial Sciences and Techology-Engineering (IWT), XIOS Hogeschool Limburg, Hasselt (Belgium); Hassan, Bassam, E-mail: b.hassan@acta.n [Department of Oral Radiology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam (Netherlands); Li Limin, E-mail: Limin.Li@uz.kuleuven.b [Department of Paediatric Dentistry and Special Dental Care, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Pauwels, Ruben, E-mail: Ruben.Pauwels@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Jacobs, Reinhilde, E-mail: Reinhilde.Jacobs@uz.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium)
2010-08-15
Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm. Results: The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively. Conclusion: The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.
Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm. Results: The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively. Conclusion: The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.
The polyGeVero® software for fast and easy computation of 3D radiotherapy dosimetry data
The polyGeVero® software package was elaborated for calculations of 3D dosimetry data such as the polymer gel dosimetry. It comprises four workspaces designed for: i) calculating calibrations, ii) storing calibrations in a database, iii) calculating dose distribution 3D cubes, iv) comparing two datasets e.g. a measured one with a 3D dosimetry with a calculated one with the aid of a treatment planning system. To accomplish calculations the software was equipped with a number of tools such as the brachytherapy isotopes database, brachytherapy dose versus distance calculation based on the line approximation approach, automatic spatial alignment of two 3D dose cubes for comparison purposes, 3D gamma index, 3D gamma angle, 3D dose difference, Pearson's coefficient, histograms calculations, isodoses superimposition for two datasets, and profiles calculations in any desired direction. This communication is to briefly present the main functions of the software and report on the speed of calculations performed by polyGeVero®
A Hierarchical Load Balancing Policy for Grid Computing Environment
Said Fathy El Zoghdy
2012-06-01
Full Text Available With the rapid development of high-speed wide-area networks and powerful yet low-cost computational resources, grid computing has emerged as an attractive computing paradigm. It provides resources for solving large scientific applications. It is typically composed of heterogeneous resources such as clusters or sites at different administrative domains connected by networks with widely varying performance characteristics. The service level of the grid software infrastructure provides two essential functions for workload and resource management. To efficiently utilize the resources at these environments, effective load balancing and resource management policies are fundamentally important. This paper addresses the problem of load balancing and task migration in grid computing environments. We propose a fully decentralized two-level load balancing policy for computationally intensive tasks on a heterogeneous multi-cluster grid environment. It resolves the single point of failure problem which many of the current policies suffer from. In this policy, any site manager receives two kinds of tasks namely, remote tasks arriving from its associated local grid manager, and local tasks submitted directly to the site manager by local users in its domain, which makes this policy closer to reality and distinguishes it from any other similar policy. It distributes the grid workload based on the resources occupation ratio and the communication cost. The grid overall mean task response time is considered as the main performance metric that need to be minimized. The simulation results show that the proposed load balancing policy improves the grid overall mean task response time.
Ilie, Adrian; Welch, Greg; Macenko, Marc
2008-01-01
International audience We present a stochastic state-space quality metric for use in controlling active camera networks aimed at 3D vision tasks such as surveillance, motion tracking, and 3D shape/appearance reconstruction. Specifically, the metric provides an estimate of the aggregate steady-state uncertainty of the 3D resolution of the objects of interest, as a function of camera parameters such as pan, tilt, and zoom. The use of stochastic state-space models for the quality metric resul...
This paper contains a description and evaluation of the thermal-hydraulic calculation of the transient connected with steam dump to atmosphere (SDA) opening during decreased reactor power to 20 % of nominal power (Nnom). The calculation was performed with the thermal-hydraulic system program ATHLET coupled with 3-D reactor dynamic code DYN3D. A comparison with the experiment was performed on the base of measured values during the SDA project function test on the VVER-1000 Temelin NPP Unit 2. Results obtained from calculated vs. experimental values could contribute to the validation of DYN3D/ATHLET coupling. (author)
Kawata, Yoshiyuki; Koizumi, Kohei
2014-10-01
The demand of 3D city modeling has been increasing in many applications such as urban planing, computer gaming with realistic city environment, car navigation system with showing 3D city map, virtual city tourism inviting future visitors to a virtual city walkthrough and others. We proposed a simple method for reconstructing a 3D urban landscape from airborne LiDAR point cloud data. The automatic reconstruction method of a 3D urban landscape was implemented by the integration of all connected regions, which were extracted and extruded from the altitude mask images. These mask images were generated from the gray scale LiDAR image by the altitude threshold ranges. In this study we demonstrated successfully in the case of Kanazawa city center scene by applying the proposed method to the airborne LiDAR point cloud data.
Parallel-Hierarchical Computing System for Multi-Level Transformation of Masked Digital Signals
YAROVYY, A. A.; TIMCHENKO, L. I.; KOKRIATSKAIA, N. I.
2012-01-01
Paper deals with organization principles of parallel-hierarchical (PH) transform for multistage perception and processing, compression and recognition of information in computational systems which make use of computational scheme similar to neural. Unified methodological approach was developed for analysis of parallel processes. This approach considers influence of structural hierarchy in dynamics. It tracks processes of spatial areas transformation of correlated and generation of uncorrel...
Rouet, François-Henry; Li, Xiaoye S.; Ghysels, Pieter; Napov, Artem
2015-01-01
We present a distributed-memory library for computations with dense structured matrices. A matrix is considered structured if its off-diagonal blocks can be approximated by a rank-deficient matrix with low numerical rank. Here, we use Hierarchically Semi-Separable representations (HSS). Such matrices appear in many applications, e.g., finite element methods, boundary element methods, etc. Exploiting this structure allows for fast solution of linear systems and/or fast computation of matrix-ve...
Illustrating the disassembly of 3D models
Guo, Jianwei
2013-10-01
We present a framework for the automatic disassembly of 3D man-made models and the illustration of the disassembly process. Given an assembled 3D model, we first analyze the individual parts using sharp edge loops and extract the contact faces between each pair of neighboring parts. The contact faces are then used to compute the possible moving directions of each part. We then present a simple algorithm for clustering the sets of the individual parts into meaningful sub-assemblies, which can be used for a hierarchical decomposition. We take the stability of sub-assemblies into account during the decomposition process by considering the upright orientation of the input models. Our framework also provides a user-friendly interface to enable the superimposition of the constraints for the decomposition. Finally, we visualize the disassembly process by generating an animated sequence. The experiments demonstrate that our framework works well for a variety of complex models. © 2013 Elsevier Ltd.
The role of 3-D imaging and computer-based postprocessing for surgery of the liver and pancreas
Cross-sectional imaging based on navigation and virtual reality planning tools are well-established in the surgical routine in orthopedic surgery and neurosurgery. In various procedures, they have achieved a significant clinical relevance and efficacy and have enhanced the discipline's resection capabilities. In abdominal surgery, however, these tools have gained little attraction so far. Even with the advantage of fast and high resolution cross-sectional liver and pancreas imaging, it remains unclear whether 3D planning and interactive planning tools might increase precision and safety of liver and pancreas surgery. The inability to simply transfer the methodology from orthopedic or neurosurgery is mainly a result of intraoperative organ movements and shifting and corresponding technical difficulties in the on-line applicability of presurgical cross sectional imaging data. For the interactive planning of liver surgery, three systems partly exist in daily routine: HepaVision2 (MeVis GmbH, Bremen), LiverLive (Navidez Ltd. Slovenia) and OrgaNicer (German Cancer Research Center, Heidelberg). All these systems have realized a half- or full-automatic liver-segmentation procedure to visualize liver segments, vessel trees, resected volumes or critical residual organ volumes, either for preoperative planning or intraoperative visualization. Acquisition of data is mainly based on computed tomography. Three-dimensional navigation for intraoperative surgical guidance with ultrasound is part of the clinical testing. There are only few reports about the transfer of the visualization of the pancreas, probably caused by the difficulties with the segmentation routine due to inflammation or organ-exceeding tumor growth. With this paper, we like to evaluate and demonstrate the present status of software planning tools and pathways for future pre- and intraoperative resection planning in liver and pancreas surgery. (orig.)
Parameswaran, Harikrishnan; Majumdar, Arnab; Suki, Béla
2011-04-01
Pulmonary emphysema is a connective tissue disease characterized by the progressive destruction of alveolar walls leading to airspace enlargement and decreased elastic recoil of the lung. However, the relationship between microscopic tissue structure and decline in stiffness of the lung is not well understood. In this study, we developed a 3D computational model of lung tissue in which a pre-strained cuboidal block of tissue was represented by a tessellation of space filling polyhedra, with each polyhedral unit-cell representing an alveolus. Destruction of alveolar walls was mimicked by eliminating faces that separate two polyhedral either randomly or in a spatially correlated manner, in which the highest force bearing walls were removed at each step. Simulations were carried out to establish a link between the geometries that emerged and the rate of decline in bulk modulus of the tissue block. The spatially correlated process set up by the force-based destruction lead to a significantly faster rate of decline in bulk modulus accompanied by highly heterogeneous structures than the random destruction pattern. Using the Karhunen-Loève transformation, an estimator of the change in bulk modulus from the first four moments of airspace cell volumes was setup. Simulations were then obtained for tissue destruction with different idealized alveolar geometry, levels of pre-strain, linear and nonlinear elasticity assumptions for alveolar walls and also mixed destruction patterns where both random and force-based destruction occurs simultaneously. In all these cases, the change in bulk modulus from cell volumes was accurately estimated. We conclude that microscopic structural changes in emphysema and the associated decline in tissue stiffness are linked by the spatial pattern of the destruction process. PMID:21533072
Barqawi, Albaha B; Lu, Li; Crawford, E David; Fenster, Aaron; Werahera, Priya N; Kumar, Dinesh; Miller, Steve; Suri, Jasjit S
2007-01-01
estimation of prostate capsule volume via segmentation of the prostate from 3-D ultrasound volumetric ultrasound images is a valuable clinical tool, especially during biopsy. Normally, a physician traces the boundaries of the prostate manually, but this process is tedious, laborious, and subject to errors. The prostate capsule edge is computed using three different strategies: (a) least square approach, (b) level set approach, and (c) Discrete Dynamic Contour approach. (a) In the least square method, edge points are defined by searching for the optimal edge based on the average signal characteristics. These edge points constitute an initial curve which is later refined; (b) Level set approach. The images are modeled as piece-wise constant, and the energy functional is defined and minimized. This method is also automated; and (c) The Discrete Dynamic Contour (DDC). A trained user selects several points in the first image and an initial contour is obtained by a model based initialization. Based on this initialization condition, the contour is deformed automatically to better fit the image. This method is semi-automatic. The three methods were tested on database consisting of 15 prostate phantom volumes acquired using a Philips ultrasound machine using an end-fire TRUS. The ground truth (GT) is developed by tracing the boundary of prostate on a slice-by-slice basis. The mean volumes using the least square, level set and DDC techniques were 15.84 cc, 15.55 cc and 16.33 cc, respectively. We validated the methods by calculating the volume with GT and we got an average volume of 15. PMID:18002081
Ramachandran, K.
2011-12-01
Three dimensional velocity models constructed through seismic tomography are seldom digitally processed further for imaging structural features. A study conducted to evaluate the potential for imaging subsurface discontinuities in horizontal and vertical direction from three dimensional velocity models using image processing/computer vision techniques has provided significant results. Three-dimensional velocity models constructed through tomographic inversion of active source and/or earthquake traveltime data are generally built from an initial 1-D velocity model that varies only with depth. Regularized tomographic inversion algorithms impose constraints on the roughness of the model that help to stabilize the inversion process. Final velocity models obtained from regularized tomographic inversions have smooth three-dimensional structures that are required by the data. Final velocity models are usually analyzed and interpreted either as a perturbation velocity model or as an absolute velocity model. Compared to perturbation velocity model, absolute velocity model has an advantage of providing constraints on lithology. Both velocity models lack the ability to provide sharp constraints on subsurface faults. However, results from the analysis of the 3-D velocity model from northern Cascadia using Roberts, Prewitt, Sobel, and Canny operators show that subsurface faults that are not clearly interpretable from velocity model plots can be identified through this approach. This analysis resulted in inferring the locations of Tacoma Fault, Seattle Fault, Southern Whidbey Island Fault, and Darrington Devils Mountain fault much clearly. The Coast Range Boundary Fault, previously hypothesized on the basis of sedimentological and tectonic observations is inferred clearly from processed images. Many of the fault locations so imaged correlate with earthquake hypocenters indicating their seismogenic nature.
Harikrishnan Parameswaran
2011-04-01
Full Text Available Pulmonary emphysema is a connective tissue disease characterized by the progressive destruction of alveolar walls leading to airspace enlargement and decreased elastic recoil of the lung. However, the relationship between microscopic tissue structure and decline in stiffness of the lung is not well understood. In this study, we developed a 3D computational model of lung tissue in which a pre-strained cuboidal block of tissue was represented by a tessellation of space filling polyhedra, with each polyhedral unit-cell representing an alveolus. Destruction of alveolar walls was mimicked by eliminating faces that separate two polyhedral either randomly or in a spatially correlated manner, in which the highest force bearing walls were removed at each step. Simulations were carried out to establish a link between the geometries that emerged and the rate of decline in bulk modulus of the tissue block. The spatially correlated process set up by the force-based destruction lead to a significantly faster rate of decline in bulk modulus accompanied by highly heterogeneous structures than the random destruction pattern. Using the Karhunen-Loève transformation, an estimator of the change in bulk modulus from the first four moments of airspace cell volumes was setup. Simulations were then obtained for tissue destruction with different idealized alveolar geometry, levels of pre-strain, linear and nonlinear elasticity assumptions for alveolar walls and also mixed destruction patterns where both random and force-based destruction occurs simultaneously. In all these cases, the change in bulk modulus from cell volumes was accurately estimated. We conclude that microscopic structural changes in emphysema and the associated decline in tissue stiffness are linked by the spatial pattern of the destruction process.
Vlachakis Dimitrios
2009-01-01
Abstract Background Usutu virus belongs to the Flaviviridae viral family and constitutes an important pathogen. The viral helicase is an ideal target for inhibitor design, since this enzyme is essential for the survival, proliferation and transmission of the virus. Results Towards a drug-design approach, the 3D model of the Usutu virus helicase structure has been designed, using conventional homology modelling techniques and the known 3D-structure of the Murray Valley Encephalitis virus helic...
TOWARD HIGHLY SECURE AND AUTONOMIC COMPUTING SYSTEMS: A HIERARCHICAL APPROACH
Lee, Hsien-Hsin S
2010-05-11
The overall objective of this research project is to develop novel architectural techniques as well as system software to achieve a highly secure and intrusion-tolerant computing system. Such system will be autonomous, self-adapting, introspective, with self-healing capability under the circumstances of improper operations, abnormal workloads, and malicious attacks. The scope of this research includes: (1) System-wide, unified introspection techniques for autonomic systems, (2) Secure information-flow microarchitecture, (3) Memory-centric security architecture, (4) Authentication control and its implication to security, (5) Digital right management, (5) Microarchitectural denial-of-service attacks on shared resources. During the period of the project, we developed several architectural techniques and system software for achieving a robust, secure, and reliable computing system toward our goal.
K. Selvaraj
2010-01-01
Full Text Available Problem statement: Literature review was mainly aiming at recognition of objects by the computer and to make explicit the information that is implicit in the attributes of 3D objects and their relative positioning in the 3D Environment (3DE as seen in the 2D images. However quantitative estimate of position of objects in the 3DE in terms of their x, y and z co-ordinates was not touched upon. This issue assumes important dimension in areas like Kinematic Design of Robos (KDR, while the Robo is negotiating with z field or Depth Field (DF. Approach: The existing methods such as pattern matching used by Robos for Depth Visualization (DV using a set of external commands, were reviewed in detail. A methodology was developed in this study to enable the Robo to quantify the depth by itself, instead of looking for external commands. Results: The Results are presented and discussed. The Results are presented and discussed. The major conclusions drawn based on the results were listed. Conclusion: The major contribution of the present study consists of computing the Depth (D1 corresponding to the depth (d measured from the photographic image of a 3DE. It had been concluded that, there exists an excellent agreement between the computed depth D1 and the corresponding actual Depth (D. The percent deviation of D1 from D (DP lies between ±2 over the entire region of the (DF. Through suitable interfacing of the developed equation with the kinematic design of Robos, the Robo can generate its own commands for DF negotiations.
Hierarchical computation in the canonical auditory cortical circuit
Atencio, Craig A.; Sharpee, Tatyana O.; Schreiner, Christoph E.
2009-01-01
Sensory cortical anatomy has identified a canonical microcircuit underlying computations between and within layers. This feed-forward circuit processes information serially from granular to supragranular and to infragranular layers. How this substrate correlates with an auditory cortical processing hierarchy is unclear. We recorded simultaneously from all layers in cat primary auditory cortex (AI) and estimated spectrotemporal receptive fields (STRFs) and associated nonlinearities. Spike-trig...
A heterogeneous hierarchical architecture for real-time computing
Skroch, D.A.; Fornaro, R.J.
1988-12-01
The need for high-speed data acquisition and control algorithms has prompted continued research in the area of multiprocessor systems and related programming techniques. The result presented here is a unique hardware and software architecture for high-speed real-time computer systems. The implementation of a prototype of this architecture has required the integration of architecture, operating systems and programming languages into a cohesive unit. This report describes a Heterogeneous Hierarchial Architecture for Real-Time (H{sup 2} ART) and system software for program loading and interprocessor communication.
Ogawa, Akitoshi; Bordier, Cecile; Macaluso, Emiliano
2013-01-01
The use of naturalistic stimuli to probe sensory functions in the human brain is gaining increasing interest. Previous imaging studies examined brain activity associated with the processing of cinematographic material using both standard "condition-based" designs, as well as "computational" methods based on the extraction of time-varying features of the stimuli (e.g. motion). Here, we exploited both approaches to investigate the neural correlates of complex visual and auditory spatial signals in cinematography. In the first experiment, the participants watched a piece of a commercial movie presented in four blocked conditions: 3D vision with surround sounds (3D-Surround), 3D with monaural sound (3D-Mono), 2D-Surround, and 2D-Mono. In the second experiment, they watched two different segments of the movie both presented continuously in 3D-Surround. The blocked presentation served for standard condition-based analyses, while all datasets were submitted to computation-based analyses. The latter assessed where activity co-varied with visual disparity signals and the complexity of auditory multi-sources signals. The blocked analyses associated 3D viewing with the activation of the dorsal and lateral occipital cortex and superior parietal lobule, while the surround sounds activated the superior and middle temporal gyri (S/MTG). The computation-based analyses revealed the effects of absolute disparity in dorsal occipital and posterior parietal cortices and of disparity gradients in the posterior middle temporal gyrus plus the inferior frontal gyrus. The complexity of the surround sounds was associated with activity in specific sub-regions of S/MTG, even after accounting for changes of sound intensity. These results demonstrate that the processing of naturalistic audio-visual signals entails an extensive set of visual and auditory areas, and that computation-based analyses can track the contribution of complex spatial aspects characterizing such life-like stimuli. PMID
Akitoshi Ogawa
Full Text Available The use of naturalistic stimuli to probe sensory functions in the human brain is gaining increasing interest. Previous imaging studies examined brain activity associated with the processing of cinematographic material using both standard "condition-based" designs, as well as "computational" methods based on the extraction of time-varying features of the stimuli (e.g. motion. Here, we exploited both approaches to investigate the neural correlates of complex visual and auditory spatial signals in cinematography. In the first experiment, the participants watched a piece of a commercial movie presented in four blocked conditions: 3D vision with surround sounds (3D-Surround, 3D with monaural sound (3D-Mono, 2D-Surround, and 2D-Mono. In the second experiment, they watched two different segments of the movie both presented continuously in 3D-Surround. The blocked presentation served for standard condition-based analyses, while all datasets were submitted to computation-based analyses. The latter assessed where activity co-varied with visual disparity signals and the complexity of auditory multi-sources signals. The blocked analyses associated 3D viewing with the activation of the dorsal and lateral occipital cortex and superior parietal lobule, while the surround sounds activated the superior and middle temporal gyri (S/MTG. The computation-based analyses revealed the effects of absolute disparity in dorsal occipital and posterior parietal cortices and of disparity gradients in the posterior middle temporal gyrus plus the inferior frontal gyrus. The complexity of the surround sounds was associated with activity in specific sub-regions of S/MTG, even after accounting for changes of sound intensity. These results demonstrate that the processing of naturalistic audio-visual signals entails an extensive set of visual and auditory areas, and that computation-based analyses can track the contribution of complex spatial aspects characterizing such life
Larios, Adam; Titi, Edriss S; Wingate, Beth
2015-01-01
We report the results of a computational investigation of two recently proved blow-up criteria for the 3D incompressible Euler equations. These criteria are based on an inviscid regularization of the Euler equations known as the 3D Euler-Voigt equations. The latter are known to be globally well-posed. Moreover, simulations of the 3D Euler-Voigt equations also require less resolution than simulations of the 3D Euler equations for fixed values of the regularization parameter $\\alpha>0$. Therefore, the new blow-up criteria allow one to gain information about possible singularity formation in the 3D Euler equations indirectly; namely, by simulating the better-behaved 3D Euler-Voigt equations. The new criteria are only known to be sufficient criteria for blow-up. Therefore, to test the robustness of the inviscid-regularization approach, we also investigate analogous criteria for blow-up of the 1D Burgers equation, where blow-up is well-known to occur.
Kucukozer, Huseyin; Korkusuz, M. Emin; Kucukozer, H. Asuman; Yurumezoglu, Kemal
2009-01-01
This study has examined the impact of teaching certain basic concepts of astronomy through a predict-observe-explain strategy, which includes three-dimensional (3D) computer modeling and observations on conceptual changes seen in sixth-grade elementary school children (aged 11-13; number of students: 131). A pre- and postastronomy instruction…
High-throughput analysis of horse sperms' 3D swimming patterns using computational on-chip imaging.
Su, Ting-Wei; Choi, Inkyum; Feng, Jiawen; Huang, Kalvin; Ozcan, Aydogan
2016-06-01
Using a high-throughput optical tracking technique that is based on partially-coherent digital in-line holography, here we report a detailed analysis of the statistical behavior of horse sperms' three-dimensional (3D) swimming dynamics. This dual-color and dual-angle lensfree imaging platform enables us to track individual 3D trajectories of ∼1000 horse sperms at sub-micron level within a sample volume of ∼9μL at a frame rate of 143 frames per second (FPS) and collect thousands of sperm trajectories within a few hours for statistical analysis of their 3D dynamics. Using this high-throughput imaging platform, we recorded >17,000 horse sperm trajectories that can be grouped into six major categories: irregular, linear, planar, helical, ribbon, and hyperactivated, where the hyperactivated swimming patterns can be further divided into four sub-categories, namely hyper-progressive, hyper-planar, hyper-ribbon, and star-spin. The large spatio-temporal statistics that we collected with this 3D tracking platform revealed that irregular, planar, and ribbon trajectories are the dominant 3D swimming patterns observed in horse sperms, which altogether account for >97% of the trajectories that we imaged in plasma-free semen extender medium. Through our experiments we also found out that horse seminal plasma in general increases sperms' straightness in their 3D trajectories, enhancing the relative percentage of linear swimming patterns and suppressing planar swimming patterns, while barely affecting the overall percentage of ribbon patterns. PMID:26826909
Precise 3D dimensional metrology using high-resolution x-ray computed tomography (μCT)
Brunke, Oliver; Santillan, Javier; Suppes, Alexander
2010-09-01
Over the past decade computed tomography (CT) with conventional x-ray sources has evolved from an imaging method in medicine to a well established technology for industrial applications in fields such as material science, light metals and plastics processing, microelectronics and geology. By using modern microfocus and nanofocus X-ray tubes, parts can be scanned with sub-micrometer resolutions. Currently, micro-CT is a technology increasingly used for metrology applications in the automotive industry. CT offers big advantages compared with conventional tactile or optical coordinate measuring machines (CMMs). This is of greater importance if complex parts with hidden or difficult accessible surfaces have to be measured. In these cases, CT offers the advantage of a high density of measurement points and a non-destructive and fast capturing of the sample's complete geometry. When using this growing technology the question arises how precise a μCT based CMM can measure as compared to conventional and established methods for coordinate measurements. For characterizing the metrological capabilities of a tactile or optical CMM, internationally standardized parameters like length measurement error and probing error are defined and used. To increase the acceptance of CT as a metrological method, our work seeks to clarify the definition and usage of parameters used in the field of metrology as these apply to CT. In this paper, an overview of the process chain in CT based metrology will be given and metrological characteristics will be described. For the potential user of CT as 3D metrology tool it is important to show the measurement accuracy and repeatability on realistic samples. Following a discussion of CT metrology techniques, two samples are discussed. The first compares a measured CT Data set to CAD data using CMM data as a standard for comparison of results. The second data second realistic data set will compare the results of applying both the CMM method of
Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran
2016-03-01
We study the conformal bootstrap for a 4-point function of fermions in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T . We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N . We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.
TRIO a general computer code for reactor 3-D flows analysis. Application to a LMFBR hot plenum
TRIO is a code developed at CEA to investigate general incompressible 2D and 3D viscous flows. Two calculations are presented: the lid driven cubic cavity at Re=400; steady state (velocity and temperature field) of a LMFBR hot plenum, carried out in order to prepare the calculation of a cold shock consecutive to a reactor scram. 8 refs., 26 figs.
Kale, Sayali B; Kalubarme, Ramchandra S; Mahadadalkar, Manjiri A; Jadhav, Harsharaj S; Bhirud, Ashwini P; Ambekar, Jalinder D; Park, Chan-Jin; Kale, Bharat B
2015-12-21
Hierarchical 3D ZnIn2S4/graphene (ZnIn2S4/Gr) nano-heterostructures were successfully synthesized using an in-situ hydrothermal method. The dual functionality of these nano-heterostructures i.e. for solar hydrogen production and lithium ion batteries has been demonstrated for the first time. The ZnIn2S4/Gr nano-heterostructures were optimized by varying the concentrations of graphene for utmost hydrogen production. An inspection of the structure shows the existence of layered hexagonal ZnIn2S4 wrapped in graphene. The reduction of graphene oxide (GO) to graphene was confirmed by Raman and XPS analyses. The morphological analysis demonstrated that ultrathin ZnIn2S4 nanopetals are dispersed on graphene sheets. The optical study reveals the extended absorption edge to the visible region due to the presence of graphene and hence is used as a photocatalyst to transform H2S into eco-friendly hydrogen using solar light. The ZnIn2S4/Gr nano-heterostructure that is comprised of graphene and ZnIn2S4 in a weight ratio of 1 : 99 exhibits enhanced photocatalytically stable hydrogen production i.e. ∼6365 μmole h(-1) under visible light irradiation using just 0.2 g of nano-heterostructure, which is much higher as compared to bare hierarchical 3D ZnIn2S4. The heightened photocatalytic activity is attributed to the enhanced charge carrier separation due to graphene which acts as an excellent electron collector and transporter. Furthermore, the usage of nano-heterostructures and pristine ZnIn2S4 as anodes in lithium ion batteries confers the charge capacities of 590 and 320 mA h g(-1) after 220 cycles as compared to their initial reversible capacities of 645 and 523 mA h g(-1), respectively. These nano-heterostructures show high reversible capacity, excellent cycling stability, and high-rate capability indicating their potential as promising anode materials for LIBs. The excellent performance is due to the nanostructuring of ZnIn2S4 and the presence of a graphene layer, which
Ginsburg, Avi; Ben-Nun, Tal; Asor, Roi; Shemesh, Asaf; Ringel, Israel; Raviv, Uri
2016-08-22
In many biochemical processes large biomolecular assemblies play important roles. X-ray scattering is a label-free bulk method that can probe the structure of large self-assembled complexes in solution. As we demonstrate in this paper, solution X-ray scattering can measure complex supramolecular assemblies at high sensitivity and resolution. At high resolution, however, data analysis of larger complexes is computationally demanding. We present an efficient method to compute the scattering curves from complex structures over a wide range of scattering angles. In our computational method, structures are defined as hierarchical trees in which repeating subunits are docked into their assembly symmetries, describing the manner subunits repeat in the structure (in other words, the locations and orientations of the repeating subunits). The amplitude of the assembly is calculated by computing the amplitudes of the basic subunits on 3D reciprocal-space grids, moving up in the hierarchy, calculating the grids of larger structures, and repeating this process for all the leaves and nodes of the tree. For very large structures, we developed a hybrid method that sums grids of smaller subunits in order to avoid numerical artifacts. We developed protocols for obtaining high-resolution solution X-ray scattering data from taxol-free microtubules at a wide range of scattering angles. We then validated our method by adequately modeling these high-resolution data. The higher speed and accuracy of our method, over existing methods, is demonstrated for smaller structures: short microtubule and tobacco mosaic virus. Our algorithm may be integrated into various structure prediction computational tools, simulations, and theoretical models, and provide means for testing their predicted structural model, by calculating the expected X-ray scattering curve and comparing with experimental data. PMID:27410762
Yang, Jixiang; Ling, Ling; Liu, Haibin
2016-01-01
Load balancing technology can effectively exploit potential enormous compute power available on distributed systems and achieve scalability. Communication delay overhead on distributed system, which is time-varying and is usually ignored or assumed to be deterministic for traditional load balancing strategies, can greatly degrade the load balancing performance. Considering communication delay overhead and its time-varying feature, a hierarchical load balancing strategy based on generalized ne...
Brown, Andrew
2014-08-01
Full Text Available This paper presents a prototype Stereolithography (STL file format slicing and tool-path generation algorithm, which serves as a data front-end for a Rapid Prototyping (RP entry- level three-dimensional (3-D printer. Used mainly in Additive Manufacturing (AM, 3-D printers are devices that apply plastic, ceramic, and metal, layer by layer, in all three dimensions on a flat surface (X, Y, and Z axis. 3-D printers, unfortunately, cannot print an object without a special algorithm that is required to create the Computer Numerical Control (CNC instructions for printing. An STL algorithm therefore forms a critical component for Layered Manufacturing (LM, also referred to as RP. The purpose of this study was to develop an algorithm that is capable of processing and slicing an STL file or multiple files, resulting in a tool-path, and finally compiling a CNC file for an entry-level 3- D printer. The prototype algorithm was implemented for an entry-level 3-D printer that utilises the Fused Deposition Modelling (FDM process or Solid Freeform Fabrication (SFF process; an AM technology. Following an experimental method, the full data flow path for the prototype algorithm was developed, starting with STL data files, and then processing the STL data file into a G-code file format by slicing the model and creating a tool-path. This layering method is used by most 3-D printers to turn a 2-D object into a 3-D object. The STL algorithm developed in this study presents innovative opportunities for LM, since it allows engineers and architects to transform their ideas easily into a solid model in a fast, simple, and cheap way. This is accomplished by allowing STL models to be sliced rapidly, effectively, and without error, and finally to be processed and prepared into a G-code print file.
Huang, L. C. P.; Cook, R. A.
1973-01-01
Models utilizing various sub-sets of the six degrees of freedom are used in trajectory simulation. A 3-D model with only linear degrees of freedom is especially attractive, since the coefficients for the angular degrees of freedom are the most difficult to determine and the angular equations are the most time consuming for the computer to evaluate. A computer program is developed that uses three separate subsections to predict trajectories. A launch rail subsection is used until the rocket has left its launcher. The program then switches to a special 3-D section which computes motions in two linear and one angular degrees of freedom. When the rocket trims out, the program switches to the standard, three linear degrees of freedom model.
Mory, Cyril, E-mail: cyril.mory@philips.com [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France); Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France); Auvray, Vincent; Zhang, Bo [Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France); Grass, Michael; Schäfer, Dirk [Philips Research, Röntgenstrasse 24–26, D-22335 Hamburg (Germany); Chen, S. James; Carroll, John D. [Department of Medicine, Division of Cardiology, University of Colorado Denver, 12605 East 16th Avenue, Aurora, Colorado 80045 (United States); Rit, Simon [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1 (France); Centre Léon Bérard, 28 rue Laënnec, F-69373 Lyon (France); Peyrin, Françoise [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France); X-ray Imaging Group, European Synchrotron, Radiation Facility, BP 220, F-38043 Grenoble Cedex (France); Douek, Philippe; Boussel, Loïc [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1 (France); Hospices Civils de Lyon, 28 Avenue du Doyen Jean Lépine, 69500 Bron (France)
2014-02-15
Purpose: Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be recorded during the acquisition and used in the reconstruction. In this paper, the authors present a 4D reconstruction method aiming to reconstruct the heart from a single sweep 10 s acquisition. Methods: The authors introduce the 4D RecOnstructiOn using Spatial and TEmporal Regularization (short 4D ROOSTER) method, which reconstructs all cardiac phases at once, as a 3D + time volume. The algorithm alternates between a reconstruction step based on conjugate gradient and four regularization steps: enforcing positivity, averaging along time outside a motion mask that contains the heart and vessels, 3D spatial total variation minimization, and 1D temporal total variation minimization. Results: 4D ROOSTER recovers the different temporal representations of a moving Shepp and Logan phantom, and outperforms both ECG-gated simultaneous algebraic reconstruction technique and prior image constrained compressed sensing on a clinical case. It generates 3D + time reconstructions with sharp edges which can be used, for example, to estimate the patient's left ventricular ejection fraction. Conclusions: 4D ROOSTER can be applied for human cardiac C-arm CT, and potentially in other dynamic tomography areas. It can easily be adapted to other problems as regularization is decoupled from projection and back projection.
Computational technology for analysis of 3D meso-structure effects on damage and failure of concrete
Wang, X.; Zhang, M.; Jivkov, A. P.
2016-01-01
Methodology for analysis of meso-structure effects on longer-scale mechanical response of concrete is developed. Efficient algorithms for particle generation and packing are proposed to represent 3D meso-structures as collections of discrete features distributed randomly in a continuous phase. Specialised to concrete, the continuous phase represents mortar, while the features are aggregates and voids. Intra- and inter-phase cohesive zones are used for failure initiation and crack propagation....
Purpose/Objective: To demonstrate that one can obtain a homogeneous dose distribution within a specified gross tumor volume (GTV) while severely limiting the dose to a structure surrounded by that tumor volume. We present three clinical examples below. Materials and Methods: Using planning CT scans from previously treated patients, we designed variety of radiation treatment plans in which the dose-critical normal structure was blocked, even if it meant blocking some of the tumor. To deal with the resulting dose inhomogeneities within the tumor, we introduced 3D compensation. Examples presented here include (1) blocking the spinal cord segment while treating an entire vertebral body, (2) blocking both kidneys while treating the entire peritoneal cavity, and (3) blocking one parotid gland while treating the oropharynx in its entirety along with regional nodes. A series of multiple planar and non-coplanar beam templates with automatic anatomic blocking and field shaping were designed for each scenario. Three-dimensional compensators were designed that gave the most homogeneous dose-distribution for the GTV. For each beam, rays were cast from the beam source through a 2D compensator grid and out through the tumor. The average tumor dose along each ray was then used to adjust the compensator thickness over successive iterations to achieve a uniform average dose. DVH calculations for the GTV, normal structures, and the 'auto-blocked' structure were made and used for inter-plan comparisons. Results: These optimized treatment plans successfully decreased dose to the dose-limiting structure while at the same time preserving or even improving the dose distribution to the tumor volume as compared to traditional treatment plans. Conclusion: The use of 3D compensation allows one to obtain dose distributions that are, theoretically, at least, far superior to those in common clinical use. Sensible beam templates, auto-blocking, auto-field shaping, and 3D compensators form a
We have investigated 3-dimensional optical random access memory (3D-ORAM) materials for detection and characterization of charged particles of neutrons by detecting tracks left by the recoil charged particles produced by the neutrons. We have characterized the response of these materials to protons, alpha particles and carbon-12 nuclei as a functions of dose and energy. We have observed individual tracks using scanning electron microscopy and atomic force microscopy. We are investigating the use of neural net analysis to characterize energetic neutron fields from their track structure in these materials
Klusoň, Jindřich
2010-01-01
Computer animation has a growing importance and application in the world. With expansion of technologies increases quality of the final animation as well as number of 3D animation software. This thesis is currently mapped animation software for creating animation in film, television industry and video games which are advisable users requirements. Of them were selected according to criteria the best - Autodesk Maya 2011. This animation software is unique with tools for creating special effects...
Hemodynamics is thought to play a very important role in the initiation, growth, and rupture of intracranial aneurysms. The purpose of our study was to compare hemodynamics of intracranial aneurysms of MR fluid dynamics (MRFD) using 3D cine PC MR imaging (4D-Flow) at 1.5 T and MR-based computational fluid dynamics (CFD). 4D-Flow was performed for five intracranial aneurysms by a 1.5 T MR scanner. 3D TOF MR angiography was performed for geometric information. The blood flow in the aneurysms was modeled using CFD simulation based on the finite element method. We used MR angiographic data as the vascular models and MR flow information as boundary conditions in CFD. 3D velocity vector fields, 3D streamlines, shearing velocity maps, wall shear stress (WSS) distribution maps and oscillatory shear index (OSI) distribution maps were obtained by MRFD and CFD and were compared. There was a moderate to high degree of correlation in 3D velocity vector fields and a low to moderate degree of correlation in WSS of aneurysms between MRFD and CFD using regression analysis. The patterns of 3D streamlines were similar between MRFD and CFD. The small and rotating shearing velocities and higher OSI were observed at the top of the spiral flow in the aneurysms. The pattern and location of shearing velocity in MRFD and CFD were similar. The location of high oscillatory shear index obtained by MRFD was near to that obtained by CFD. MRFD and CFD of intracranial aneurysms correlated fairly well. (orig.)
Yu, Huidan (Whitney); Chen, Xi; Chen, Rou; Wang, Zhiqiang; Lin, Chen; Kralik, Stephen; Zhao, Ye
2015-11-01
In this work, we demonstrate the validity of 4-D patient-specific computational hemodynamics (PSCH) based on 3-D time-of-flight (TOF) MR angiography (MRA) and 2-D electrocardiogram (ECG) gated phase contrast (PC) images. The mesoscale lattice Boltzmann method (LBM) is employed to segment morphological arterial geometry from TOF MRA, to extract velocity profiles from ECG PC images, and to simulate fluid dynamics on a unified GPU accelerated computational platform. Two healthy volunteers are recruited to participate in the study. For each volunteer, a 3-D high resolution TOF MRA image and 10 2-D ECG gated PC images are acquired to provide the morphological geometry and the time-varying flow velocity profiles for necessary inputs of the PSCH. Validation results will be presented through comparisons of LBM vs. 4D Flow Software for flow rates and LBM simulation vs. MRA measurement for blood flow velocity maps. Indiana University Health (IUH) Values Fund.
3D Partition-Based Clustering for Supply Chain Data Management
Suhaibah, A.; Uznir, U.; Anton, François;
2015-01-01
coverage are computed and compared with the original 3D R-Tree and other practical approaches. The experiments demonstrated in this paper substantiated that the hierarchical structure of the proposed partition-based clustering is capable of preserving minimal overlap and coverage. The query performance was...
Atala Bihari Jena
2013-09-01
Full Text Available With the advent of biomedical research in the field of human science several protein are found in human body acts s a health hazard. The proto-oncogene c-Rel protein is mostly found in human is encoded by the REL gene and belongs to the Rel/NF- kB transcription factor family, which regulates a large variety of cellular functions. Proto-oncogene involved and plays a great role in differentiation and lymphopoiesis. Proto-oncogene may be harmful and cause cancer when they are mutated. To understand the operational mechanism of HUMAN Proto-oncogene c-Rel protein, it is imperative to understand the structural model of that particular protein but the three dimensional (3D structure has not yet been reported in Protein Data Bank (PDB. In the present study a complete structural analysis and 3-D modelling of HUMAN Proto-oncogene c-Rel of Homosapiens.Based on the PDB Blast report three dimensional structure of the Proto-oncogenec-Rel protein, was predicted by using the SWISS MODEL. Predicted model was further assessed by SAVES (PROCHEK, VERIFY 3D, ERRAT and Ramachandran Server, which show with acceptable scores and the reliability of final refined model. The overall result provides the evidence of good quality of model and furnishes an adequate foundation for functional analysis of experimentally derived crystal structures and also helps in cancer research with furnishes a novel starting point for structure based drug design of proto-oncogene c-Rel protein.
The repair of great mandibular defects is still a real problem in the maxillo-facial surgery. During the treatment planning we use very often only two-dimensional radiographic images and cefalometric analysis. Their possibility to measure three-dimensionally is limited. On the base of 3D-images, created by computer-tomographical SSD - technique, we present a new method to justify the size and anatomical form of the autogenous transplants during mandibular reconstruction
Salazar, Gary A; Masujima, Tsutomu
2008-09-01
The behavior of a completely new ion trap is shown with SIMION 7.0 simulations. The simulated trap, which was a mix of a linear and a 3D trap, was made by axially setting two ion guides with a gap between them. Each guide consisted of three rods with three symmetrically delayed radio frequency (rf) voltages (tripole). The "injected" ions were linearly contained by pulsed potentials on the entrance and exit plates. Then the three-dimensional (3D) rf field in the gap, which was created by the tripole special rod arrangement, could trap the ions when the translational energy was dampened by collisions with low-pressure nitrogen. Because the injected ions were trapped in the small gap, the trapping cycle could be repeated many times before ion ejection, so a high concentrated ion cloud could be obtained. This trapping and accumulation methodology is not possible in most conventional multipole linear traps with even number of poles. Compared with quadrupole linear trap at the same rf amplitude, tripole lost more ions due to strong charge repulsion in the ion cloud. However, tripole could catch up the ions at higher voltage. Radial and axial mass-independent ejection of the ions localized in the tripole gap was very simple, compared with conventional linear ion traps that need extra and complicated electrodes for effective axial ejection. PMID:18635376
Beyersdorff, D.; Taupitz, M.; Hamm, B. [Dept. of Radiology, Humboldt Univ., Berlin (Germany); Schiemann, T. [Inst. for Mathematics and Computer Science in Medicine, University of Hamburg (Germany); Kooijman, H. [Philips Medical Systems, Hamburg (Germany); Nicolas, V. [Dept. of Radiology and Nuclear Medicine, BG Kliniken Bergmannsheil, Bochum (Germany)
2001-04-01
The structures of the pelvic floor are clinically important but difficult to assess. To facilitate the understanding of the complicated pelvic floor anatomy on sectional images obtained by CT and MR imaging, and to make the representation more vivid, a computer-aided 3D model was created from a male and a female torso to develop a teaching tool. A male and a female cadaver torso were investigated by means of CT, MR imaging, and serial-section sheet plastination. A 3D reconstruction of the pelvic floor and adjacent structures was performed by fusion of CT and MR imaging data sets with sheet plastination sections. Corresponding sections from all three methods could be compared and visualized in their 3D context. Sheet plastination allows distinction of connective tissue, muscles, and pelvic organs down to a microscopic level. In combination with CT, MR imaging, and sheet plastination a 3D model of the pelvic floor offers a better understanding of the complex pelvic anatomy. This knowledge may be applied in the diagnostic imaging of urinary incontinence or prolapse and prior to prostate surgery. (orig.)
The structures of the pelvic floor are clinically important but difficult to assess. To facilitate the understanding of the complicated pelvic floor anatomy on sectional images obtained by CT and MR imaging, and to make the representation more vivid, a computer-aided 3D model was created from a male and a female torso to develop a teaching tool. A male and a female cadaver torso were investigated by means of CT, MR imaging, and serial-section sheet plastination. A 3D reconstruction of the pelvic floor and adjacent structures was performed by fusion of CT and MR imaging data sets with sheet plastination sections. Corresponding sections from all three methods could be compared and visualized in their 3D context. Sheet plastination allows distinction of connective tissue, muscles, and pelvic organs down to a microscopic level. In combination with CT, MR imaging, and sheet plastination a 3D model of the pelvic floor offers a better understanding of the complex pelvic anatomy. This knowledge may be applied in the diagnostic imaging of urinary incontinence or prolapse and prior to prostate surgery. (orig.)
Taming Supersymmetric Defects in 3d-3d Correspondence
Gang, Dongmin; Romo, Mauricio; Yamazaki, Masahito
2015-01-01
We study knots in 3d Chern-Simons theory with complex gauge group $SL(N,\\mathbb{C})$, in the context of its relation with 3d $\\mathcal{N}=2$ theory (the so-called 3d-3d correspondence). The defect has either co-dimension 2 or co-dimension 4 inside the 6d $(2,0)$ theory, which is compactified on a 3-manifold $\\hat{M}$. We identify such defects in various corners of the 3d-3d correspondence, namely in 3d $SL(N,\\mathbb{C})$ Chern-Simons theory, in 3d $\\mathcal{N}=2$ theory, in 5d $\\mathcal{N}=2$ super Yang-Mills theory, and in the M-theory holographic dual. We can make quantitative checks of the 3d-3d correspondence by computing partition functions at each of these theories. This Letter is a companion to a longer paper, which contains more details and more results.
WANG Jian-hua; HAO Yu-xin
2011-01-01
Based on the necessity of three dimensional modeling with computer in teaching reform, this paper is the summarization of reform practice of teaching engineering drawing in our institute. The teaching reform begins with three dimensional modeling that used computer instead of board. On the basis of target of teaching reform, set of teaching content, arrangement of class hour and teaching method, the research of teaching practice have been done, and very good effects in teaching of engineering drawing have been achieved.
Rømer, Daniel; Johansen, Per; Pedersen, Henrik C.;
2013-01-01
A fast rotating 1500 rpm radial piston digital displacement motor connected to a 350 bar high pressure manifold is simulated by means of transient 3D CFD analysis of a single pressure chamber. The analysis includes dynamic piston and valve movement, influencing the boundaries of the fluid domain....... Movement of the low and high pressure valves is coupled to fluid forces and valve actuation is included to control the valve movement according to the pressure cycle of the digital displacement motor. The fluid domain is meshed using a structured/unstructured non-conformal mesh, which is updated throughout...... the simulation using layering zones as required by the moving fluid boundaries. The effect of cavitation at low pressures is included by implementing a pressure dependent density, based on an effective bulk modulus model. In addition, pressure dependent oil viscosity is included in the analysis. As a...
PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)
Buning, P.
1994-01-01
PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into
PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)
Buning, P.
1994-01-01
PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into
A 3D multilevel model of damage and strength of wood: Analysis of microstructural effects
Qing, Hai; Mishnaevsky, Leon
2011-01-01
A 3D hierarchical computational model of damage and strength of wood is developed. The model takes into account the four scale microstructures of wood, including the microfibril reinforced structure at nanoscale, multilayered cell walls at microscale, hexagon-shape-tube cellular structure at meso...... arrangements and cellulose strength distributions on the tensile strength of wood is studied numerically. Good agreement of the theoretical results with experimental data has been obtained.......A 3D hierarchical computational model of damage and strength of wood is developed. The model takes into account the four scale microstructures of wood, including the microfibril reinforced structure at nanoscale, multilayered cell walls at microscale, hexagon-shape-tube cellular structure at...... mesoscale and annual rings at the macroscale. With the use of the developed hierarchical model, the influence of the microstructure, including microfibril angle (MFA), the cell shape and the wood density (annual ring structure), differences between earlywood and latewood as well as microstructural...
Coen Pramono D
2005-03-01
Full Text Available Functional and aesthetic dysgnathia surgery requires accurate pre-surgical planning, including the surgical technique to be used related with the difference of anatomical structures amongst individuals. Programs that simulate the surgery become increasingly important. This can be mediated by using a surgical model, conventional x-rays as panoramic, cephalometric projections and another sophisticated method such as a three dimensional computed tomography (3 D-CT. A patient who had undergone double jaw surgeries with difficult anatomical landmarks was presented. In this case the mandible foramens were seen highly relatively related to the sigmoid notches. Therefore, ensuring the bone incisions in sagittal split was presumed to be difficult. A 3D-CT was made and considered to be very helpful in supporting the pre-operative diagnostic.
Sulzmann, Armin; Carlier, Jerome; Jacot, Jacques
1996-10-01
The aim of this project is to telecontrol the movements in 3D-space of a microscope in order to manipulate and measure microsystems or micro parts aided by multi-user virtual reality (VR) environments. Presently microsystems are gaining in interest. Microsystems are small, independent modules, incorporating various functions, such as electronic, micro mechanical, data processing, optical, chemical, medical and biological functions. Though improving the manufacturing technologies, the measurement of the small structures to insure the quality of the process is a key information for the development. So far to measure the micro structures strong microscopes are needed. The use of highly magnifying computerized microscopes is expensive. To insure high quality measurements and distribute the acquired information to multi-user our proposed system is divided into three parts: the virtual reality microscopic environment (VRME)-based user-interface on a SGI workstation to prepare the manipulations and measurements. Secondly the computerized light microscope with the vision system inspecting the scene and getting the images of the specimen. Newly developed vision algorithms are used to analyze micro structures in the scene corresponding to the known a priori model. This vision is extracting position and shape of the objects and then transmitted as feedback to the user of the VRME-system to update his virtual environment. The internet demon is the third part of the system and distributes the information about the position of the micro structures, their shape and the images to the connected users who themselves may interact with the microscope (turn and displace the specimen on the back of a moving platform, or adding their structures to the scene and compare). The key idea behind our project VRME is to use the intuitiveness and the 3D visualization of VR environments coupled with a vision system to perform measurements of micro structures at a high accuracy. The direct
Goggin, P M; Zygalakis, K C; Oreffo, R O; Schneider, P
2016-01-01
Osteocytes are involved in mechanosensation and mechanotransduction in bone and hence, are key to bone adaptation in response to development, ageing and disease. Thus, detailed knowledge of the three-dimensional (3D) structure of the osteocyte network (ON) and the surrounding lacuno-canalicular network (LCN) is essential. Enhanced understanding of the ON&LCN will contribute to a better understanding of bone mechanics on cellular and sub-cellular scales, for instance through improved computational models of bone mechanotransduction. Until now, the location of the ON within the hard bone matrix and the sub-µm dimensions of the ON&LCN have posed significant challenges for 3D imaging. This review identifies relevant microstructural phenotypes of the ON&LCN in health and disease and summarises how light microscopy, electron microscopy and X-ray imaging techniques have been used in studies of osteocyte anatomy, pathology and mechanobiology to date. In this review, we assess the requirements for ON&LCN imaging and examine the state of the art in the fields of imaging and computational modelling as well as recent advances in high-resolution 3D imaging. Suggestions for future investigations using volume electron microscopy are indicated and we present new data on the ON&LCN using serial block-face scanning electron microscopy. A correlative approach using these high-resolution 3D imaging techniques in conjunction with in silico modelling in bone mechanobiology will increase understanding of osteocyte function and, ultimately, lead to improved pathways for diagnosis and treatment of bone diseases such as osteoporosis. PMID:27209400
In the context of the FP7 European THINS Project, complex thermal-hydraulic phenomena relevant for the Generation IV of nuclear reactors are investigated. KTH (Sweden) built the TALL-3D facility to investigate the transition from forced to natural circulation of the Lead-Bismuth Eutectic (LBE) in a pool connected to a 3-leg primary circuit with two heaters and a heat exchanger. The simulation of such 3D phenomena is a challenging task. GRS (Germany) developed the coupling between the Computational Fluid Dynamics (CFD) code ANSYS CFX and the System Analysis code ATHLET. Such coupled codes combine the advantages of CFD, which allow a fine resolution of 3D phenomena, and of System Analysis codes, which are fast running. TUM (Germany) is responsible for the Uncertainty and Sensitivity Analysis of the coupled ATHLET-CFX model in the THINS Project. The influence of modeling uncertainty on simulation results needs to be assessed to characterize and to improve the model and, eventually, to assess its performance against experimental data. TUM has developed a computational framework capable of propagating model input uncertainty through coupled codes. This framework can also be used to apply different approaches for the assessment of the influence of the uncertain input parameters on the model output (Sensitivity Analysis). The work reported in this paper focuses on three methods for the assessment of the sensitivity of the results to the modeling uncertainty. The first method (Morris) allows for the computation of the Elementary Effects resulting from the input parameters. This method is widely used to perform Screening Analysis. The second method (Spearman's rank correlation) relies on regression-based non-parametric measures. This method is suitable if the relation between the input and the output variables is at least monotonic, with the advantage of a low computational cost. The last method (Sobol') computes so-called total effect indices which account for
3D-QSPR Method of Computational Technique Applied on Red Reactive Dyes by Using CoMFA Strategy
Shahnaz Perveen
2011-12-01
Full Text Available Cellulose fiber is a tremendous natural resource that has broad application in various productions including the textile industry. The dyes, which are commonly used for cellulose printing, are “reactive dyes” because of their high wet fastness and brilliant colors. The interaction of various dyes with the cellulose fiber depends upon the physiochemical properties that are governed by specific features of the dye molecule. The binding pattern of the reactive dye with cellulose fiber is called the ligand-receptor concept. In the current study, the three dimensional quantitative structure property relationship (3D-QSPR technique was applied to understand the red reactive dyes interactions with the cellulose by the Comparative Molecular Field Analysis (CoMFA method. This method was successfully utilized to predict a reliable model. The predicted model gives satisfactory statistical results and in the light of these, it was further analyzed. Additionally, the graphical outcomes (contour maps help us to understand the modification pattern and to correlate the structural changes with respect to the absorptivity. Furthermore, the final selected model has potential to assist in understanding the charachteristics of the external test set. The study could be helpful to design new reactive dyes with better affinity and selectivity for the cellulose fiber.
Stratos Galanopoulos
2014-08-01
Full Text Available We report on the design, modeling and fabrication by multi-photon polymerization of a complex medical fluidic device. The physical dimensions of the built micro-valve prototype are compared to those of its computer-designed model. Important fabrication issues such as achieving high dimensional resolution and ability to control distortion due to shrinkage are presented and discussed. The operational performance of both multi-photon and CAD-created models under steady blood flow conditions was evaluated and compared through computational fluid dynamics analysis.
DEVELOPING VIRTUAL ENVIRONMENTS OF COMPUTER HARDWARE USING HIERARCHICAL-EMBEDDED VIRTUAL OBJECTS
Wan Mohd Rizhan Wan Idris
2013-10-01
Full Text Available Various fields have been taking opportunities to fully utilize the strengths of Virtual Reality (VR in developing robust and sophisticated applications. Computer hardware is one of the important topics formally and informally learned by students in all programs in universities and even in schools. Knowledge of computers become mandatory to learn since the students get involved in daily utilizing the computers for finishing assignments, social networking, downloading notes, answering test or quiz online and other learning and teaching activities involving the computers. Since the computer hardware consists of many devices, understanding and recognizing the devices are essential especially for the students who formally register or take this course. Furthermore, this registered course usually has its assessments such as examination, quiz and assignment to be evaluated. Due to the lacks and problems in recognizing the devices, they can lead to the misunderstanding and mistakes in the usages of the computers. In this paper, the development of virtual environments for the computer hardware using HEVO method has been proposed and discussed in detail to allow teachers creating and managing the 3D computer hardware and to enable students viewing, interacting and navigating in the VEs. Levels of students’ knowledge and skill for this topic as well as the usability study of the created VEs are also analysed and evaluated.
Computer simulation of 3D steady and 2D transient loading of CASTOR 440/84 using FEM
The system of computer codes, developed at the NRI Rez, plc. for the CEZ a.s. company, is described, aimed to the realistic best estimate evaluations of the temperature field in the CASTOR 440/84 container, which is used for the Dukovany NPP spent fuel. (author)
Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen
2011-01-01
introduced in this paper is much easier to use and is computational faster. This method is derived based on the “apparent energy.” Calculation of the nonlinear flux linkage from this energy avoids numerical differentiation, which is sensitive to numerical errors but is required in the traditional energy...
MOSRA-LIGHT, High Speed 3-D X-Y-Z Nodal Diffusion Code for Vector Computers
1 - Description of program or function: MOSRA-Light is a three-dimensional neutron diffusion calculation code for X-Y-Z geometry. 2 - Methods: It is based on the 4. order polynomial nodal expansion method (NEM). As the 4. order NEM is not sensitive to mesh sizes, accurate calculation is possible by the use of coarse meshes of about 20 cm. The drastic decrease of number of unknowns is a 3-dimensional problem results in very fast computation. Furthermore, it employs newly developed computation algorithm 'boundary separated checkerboard sweep method' appropriate to vector computers. This method is very efficient because the speedup factor by vectorization increases, as a scale of problem becomes lager. Speed-up factor compared to the scalar calculation is from 20 to 40 in the case of PWR core calculation. Considering the both effects by the vectorization and the coarse mesh method, total speedup factor is more than 1000 as compared with conventional scalar code with the finite difference method. The general theory of NEM, the fast computation algorithm, benchmark calculation results and detailed information for usage of this code including input data instruction and sample input data is described in the documentation
Lucas, Laurent; Loscos, Céline
2013-01-01
While 3D vision has existed for many years, the use of 3D cameras and video-based modeling by the film industry has induced an explosion of interest for 3D acquisition technology, 3D content and 3D displays. As such, 3D video has become one of the new technology trends of this century.The chapters in this book cover a large spectrum of areas connected to 3D video, which are presented both theoretically and technologically, while taking into account both physiological and perceptual aspects. Stepping away from traditional 3D vision, the authors, all currently involved in these areas, provide th
Electrical impedance tomography (EIT) is a fast and cost-effective technique to provide a tomographic conductivity image of a subject from boundary current–voltage data. This paper proposes a time and memory efficient method for solving a large scale 3D EIT inverse problem using a parallel conjugate gradient (CG) algorithm. The 3D EIT system with a large number of measurement data can produce a large size of Jacobian matrix; this could cause difficulties in computer storage and the inversion process. One of challenges in 3D EIT is to decrease the reconstruction time and memory usage, at the same time retaining the image quality. Firstly, a sparse matrix reduction technique is proposed using thresholding to set very small values of the Jacobian matrix to zero. By adjusting the Jacobian matrix into a sparse format, the element with zeros would be eliminated, which results in a saving of memory requirement. Secondly, a block-wise CG method for parallel reconstruction has been developed. The proposed method has been tested using simulated data as well as experimental test samples. Sparse Jacobian with a block-wise CG enables the large scale EIT problem to be solved efficiently. Image quality measures are presented to quantify the effect of sparse matrix reduction in reconstruction results. (paper)
Wargo, E. A.; Kotaka, T.; Tabuchi, Y.; Kumbur, E. C.
2013-11-01
Focused ion beam-scanning electron microscopy (FIB-SEM) and nano-scale X-ray computed tomography (nano-CT) have emerged as two popular nanotomography techniques for quantifying the 3-D microstructure of porous materials. The objective of this study is to assess the unique features and limitations of FIB-SEM and nano-CT in capturing the 3-D microstructure and structure-related transport properties of porous fuel cell materials. As a test case, a sample of a micro-porous layer used in polymer electrolyte fuel cells is analyzed to obtain 3-D microstructure datasets using these two nanotomography techniques. For quantitative comparison purposes, several key transport properties are determined for these two datasets, including the porosity, pore connectivity, tortuosity, structural diffusivity coefficient, and chord length (i.e., void size) distributions. The results obtained for both datasets are evaluated against each other and experimental data when available. Additionally, these two techniques are compared qualitatively in terms of the acquired images, image segmentation, and general systems operation. The particular advantages and disadvantages of both techniques are highlighted, along with suggestions for best practice.
Hierarchical Non-blocking Coordinated Checkpointing Algorithms for Mobile Distributed Computing
Parveen Kumar
2010-01-01
Full Text Available Mobile system typically uses wireless communication which is based on electromagnetic waves and utilizes a shared broadcast medium. This has made possible creating a mobile distributed computing environment and has brought us several new challenges in distributed protocol design. So many issues such as range of transmission, limited power supply due to battery capacity and mobility of processes. These new issue makes traditional recovery algorithm unsuitable. In this paper, we propose hierarchical non blocking coordinated checkpointing algorithms suitable for mobile distributed computing. The algorithm is non-blocking, requires minimum message logging, has minimum stable storage requirement and produce a consistent set of checkpoints. This algorithm requires minimum number of processes to take checkpoint.
Zimmerling, Jörn; Wei, Lei; Urbach, Paul; Remis, Rob
2016-03-01
We present a Krylov model-order reduction approach to efficiently compute the spontaneous decay (SD) rate of arbitrarily shaped 3D nanosized resonators. We exploit the symmetry of Maxwell's equations to efficiently construct so-called reduced-order models that approximate the SD rate of a quantum emitter embedded in a resonating nanostructure. The models allow for frequency sweeps, meaning that a single model provides SD rate approximations over an entire spectral interval of interest. Field approximations and dominant quasinormal modes can be determined at low cost as well.
Bull, D. J.; Helfen, L.; Sinclair, I.; Spearing, S.M.
2012-01-01
3D X-ray computed tomography (CT) was used to study the effects of particle toughening within unidirectional carbon fibre reinforced polymer (CFRP) materials subjected to impact damage, followed by ex situ CT of compression after impact (CAI) tests at incremental loads. A multi-scale approach utilizing synchrotron radiation CT and laminography was used to study the damage micro-mechanisms of impact-loaded specimens, and micro-focus CT (?CT) assessed damage at meso- and macro-scopic levels. Fo...
Borowska-Solonynko, Aleksandra; Solonynko, Bohdan
2015-02-01
Forensic pathologists are often called upon to determine the mechanism and severity of injuries in living individuals. Such expert testimony is often based solely on hand-written clinical notes. The victims' injuries may also be visualized via three-dimensional (3D) reconstruction of computed tomography (CT) images. This method has certain benefits but is not free from limitations. This paper presents two case reports. The first case is that of a female who was brought to the hospital with a knife thrust into her body. The prosecutor's questions focused on the wound channel. The information obtained from the patient's medical records was very general with many contradictory statements. A re-evaluation of the available CT scan data and a subsequent 3D reconstruction helped determine the exact course of the wound channel. The other case was that of a young male, hospitalized based on CT evidence of bilateral rib fractions, who claimed to have been assaulted by police officers. Court expert witnesses were already in possession of a 3D reconstruction showing symmetrical fractures of the patient's lower ribs with bone fragment displacement. An expert witness in radiology definitively excluded the presence of any actual fractures, and explained their apparent visibility in the three-dimensionally reconstructed image as a motion artifact. These two cases suggest that a professionally conducted 3D CT reconstruction is a very useful tool in providing expert testimony on injuries in living victims. However, the deceptive simplicity of conducting such a reconstruction may encourage inexperienced individuals to undertake it, and thus lead to erroneous conclusions. PMID:25623187
Amanda Scherer
Full Text Available We have developed a 4D computer-assisted reconstruction and motion analysis system, J3D-DIAS 4.1, and applied it to the reconstruction and motion analysis of tumorigenic cells in a 3D matrix. The system is unique in that it is fast, high-resolution, acquires optical sections using DIC microscopy (hence there is no associated photoxicity, and is capable of long-term 4D reconstruction. Specifically, a z-series at 5 μm increments can be acquired in less than a minute on tissue samples embedded in a 1.5 mm thick 3D Matrigel matrix. Reconstruction can be repeated at intervals as short as every minute and continued for 30 days or longer. Images are converted to mathematical representations from which quantitative parameters can be derived. Application of this system to cancer cells from established lines and fresh tumor tissue has revealed unique behaviors and cell types not present in non-tumorigenic lines. We report here that cells from tumorigenic lines and tumors undergo rapid coalescence in 3D, mediated by specific cell types that we have named "facilitators" and "probes." A third cell type, the "dervish", is capable of rapid movement through the gel and does not adhere to it. These cell types have never before been described. Our data suggest that tumorigenesis in vitro is a developmental process involving coalescence facilitated by specialized cells that culminates in large hollow spheres with complex architecture. The unique effects of select monoclonal antibodies on these processes demonstrate the usefulness of the model for analyzing the mechanisms of anti-cancer drugs.
Sarrami-Foroushani
2015-10-01
Full Text Available Background Understanding hemodynamic environment in vessels is important for realizing the mechanisms leading to vascular pathologies. Objectives Three-dimensional velocity vector field in carotid bifurcation is visualized using TR 3D phase-contrast magnetic resonance imaging (TR 3D PC MRI and computational fluid dynamics (CFD. This study aimed to present a qualitative and quantitative comparison of the velocity vector field obtained by each technique. Subjects and Methods MR imaging was performed on a 30-year old male normal subject. TR 3D PC MRI was performed on a 3 T scanner to measure velocity in carotid bifurcation. 3D anatomical model for CFD was created using images obtained from time-of-flight MR angiography. Velocity vector field in carotid bifurcation was predicted using CFD and PC MRI techniques. A statistical analysis was performed to assess the agreement between the two methods. Results Although the main flow patterns were the same for the both techniques, CFD showed a greater resolution in mapping the secondary and circulating flows. Overall root mean square (RMS errors for all the corresponding data points in PC MRI and CFD were 14.27% in peak systole and 12.91% in end diastole relative to maximum velocity measured at each cardiac phase. Bland-Altman plots showed a very good agreement between the two techniques. However, this study was not aimed to validate any of methods, instead, the consistency was assessed to accentuate the similarities and differences between Time-resolved PC MRI and CFD. Conclusion Both techniques provided quantitatively consistent results of in vivo velocity vector fields in right internal carotid artery (RCA. PC MRI represented a good estimation of main flow patterns inside the vasculature, which seems to be acceptable for clinical use. However, limitations of each technique should be considered while interpreting results.
Shapiro, A.B.
1983-08-01
The computer code FACET calculates the radiation geometric view factor (alternatively called shape factor, angle factor, or configuration factor) between surfaces for axisymmetric, two-dimensional planar and three-dimensional geometries with interposed third surface obstructions. FACET was developed to calculate view factors for input to finite-element heat-transfer analysis codes. The first section of this report is a brief review of previous radiation-view-factor computer codes. The second section presents the defining integral equation for the geometric view factor between two surfaces and the assumptions made in its derivation. Also in this section are the numerical algorithms used to integrate this equation for the various geometries. The third section presents the algorithms used to detect self-shadowing and third-surface shadowing between the two surfaces for which a view factor is being calculated. The fourth section provides a user's input guide followed by several example problems.
Ross, Muriel D.; Meyer, Glenn; Lam, Tony; Cutler, Lynn; Vaziri, Parshaw
1990-01-01
Computer-assisted reconstructions of small parts of the macular neural network show how the nerve terminals and receptive fields are organized in 3-dimensional space. This biological neural network is anatomically organized for parallel distributed processing of information. Processing appears to be more complex than in computer-based neural network, because spatiotemporal factors figure into synaptic weighting. Serial reconstruction data show anatomical arrangements which suggest that (1) assemblies of cells analyze and distribute information with inbuilt redundancy, to improve reliability; (2) feedforward/feedback loops provide the capacity for presynaptic modulation of output during processing; (3) constrained randomness in connectivities contributes to adaptability; and (4) local variations in network complexity permit differing analyses of incoming signals to take place simultaneously. The last inference suggests that there may be segregation of information flow to central stations subserving particular functions.
Exact computation of the Voronoi Diagram of spheres in 3D, its topology and its geometric invariants
Anton, François; Mioc, Darka; Santos, Marcelo
2011-01-01
regrouping all the formal coefficients for each monomial in each polynomial, we get polynomials that are invariants for the given problem. We rewrite the original system by replacing the invariant polynomials by new formal coefficients. We repeat the process until all the algebraic relationships (syzygies...... treatment of the exact computation with geometrical invariants of the Delaunay graph and the Voronoi diagram of spheres. Starting from the system of equations defining the zero-dimensional algebraic set of the problem, we are following Wu’s algorithm to transform the initial system into an equivalent Wu...... characteristic (triangular) set. In the corresponding system of algebraic equations, in each polynomial (except the first one), the variable with higher order from the preceding polynomial has been eliminated (by pseudo-remainder computations) and the last polynomial is a polynomial of a single variable. By...
Bulovyatov, Alexander
2010-01-01
The band structure computation turns into solving a family of Maxwell eigenvalue problems on the periodicity domain. The discretization is done by the finite element method with special higher order H(curl)- and H1-conforming modified elements. The eigenvalue problem is solved by a preconditioned iterative eigenvalue solver with a projection onto the divergence-free vector fields. As a preconditioner we use the parallel multigrid method with a special Hiptmair smoother.
A fast and efficient algorithm to compute BPX- and overlapping preconditioner for adaptive 3D-FEM
Eibner, Tino
2008-01-01
In this paper we consider the well-known BPX-preconditioner in conjunction with adaptive FEM. We present an algorithm which enables us to compute the preconditioner with optimal complexity by a total of only O(DoF) additional memory. Furthermore, we show how to combine the BPX-preconditioner with an overlapping Additive-Schwarz-preconditioner to obtain a preconditioner for finite element spaces with arbitrary polynomial degree distributions. Numerical examples illustr...
Meireles, Agnes Batista; Vieira, Antonio Wilson; Corpas, Livia; Vandenberghe, Bart; Bastos, Flavia Souza; Lambrechts, Paul; Campos, Mario Montenegro; Las Casas, Estevam Barbosa de
2016-01-01
The objective of this work was to propose an automated and direct process to grade tooth wear intra-orally. Eight extracted teeth were etched with acid for different times to produce wear and scanned with an intra-oral optical scanner. Computer vision algorithms were used for alignment and comparison among models. Wear volume was estimated and visual scoring was achieved to determine reliability. Results demonstrated that it is possible to directly detect submillimeter differences in teeth surfaces with an automated method with results similar to those obtained by direct visual inspection. The investigated method proved to be reliable for comparison of measurements over time. PMID:26047162
Full text: A computational program was developed for reactor fuel management in three dimensional Cartesian coordinates using two-group neutron diffusion theory (fast neutron and thermal neutron energy group). Three fuel loading patterns were considered as follow: 1. uniform loading, 2. out-in loading and 3. in-scatter loading. Criticality, peak power distribution and loaded fuel depletion measured in megawatt-day per kilogram (MW d/kg) of uranium were also calculated by the developed program. The results showed that the in-scatter loading pattern gave the best power peaking for fuel management
Ross, Muriel D.; Cutler, Lynn; Meyer, Glenn; Lam, Tony; Vaziri, Parshaw
1990-01-01
Computer-assisted, 3-dimensional reconstructions of macular receptive fields and of their linkages into a neural network have revealed new information about macular functional organization. Both type I and type II hair cells are included in the receptive fields. The fields are rounded, oblong, or elongated, but gradations between categories are common. Cell polarizations are divergent. Morphologically, each calyx of oblong and elongated fields appears to be an information processing site. Intrinsic modulation of information processing is extensive and varies with the kind of field. Each reconstructed field differs in detail from every other, suggesting that an element of randomness is introduced developmentally and contributes to endorgan adaptability.
Wood, Jo; Kirschenbauer, Sabine; Döllner, Jürgen;
2005-01-01
The notion of three-dimensionality is applied to five stages of the visualization pipeline. While 3D visulization is most often associated with the visual mapping and representation of data, this chapter also identifies its role in the management and assembly of data, and in the media used...... to display 3D imagery. The extra cartographic degree of freedom offered by using 3D is explored and offered as a motivation for employing 3D in visualization. The use of VR and the construction of virtual environments exploit navigational and behavioral realism, but become most usefil when combined...... with abstracted representations embedded in a 3D space. The interactions between development of geovisualization, the technology used to implement it and the theory surrounding cartographic representation are explored. The dominance of computing technologies, driven particularly by the gaming industry...
Lai, Canhai; Xu, Zhijie; Pan, Wenxiao; Sun, Xin; Storlie, Curtis; Marcy, Peter; Dietiker, Jeff; Li, Tingwen; Spenik, James
2016-02-22
To quantify the predictive confidence of a solid sorbent-based carbon capture design, a hierarchical validation methodology—consisting of basic unit problems with increasing physical complexity coupled with filtered model-based geometric upscaling has been developed and implemented. This paper describes the computational fluid dynamics (CFD) multi-phase reactive flow simulations and the associated data flows among different unit problems performed within the said hierarchical validation approach. The bench-top experiments used in this calibration and validation effort were carefully designed to follow the desired simple-to-complex unit problem hierarchy, with corresponding data acquisition to support model parameters calibrations at each unit problem level. A Bayesian calibration procedure is employed and the posterior model parameter distributions obtained at one unit-problem level are used as prior distributions for the same parameters in the next-tier simulations. Overall, the results have demonstrated that the multiphase reactive flow models within MFIX can be used to capture the bed pressure, temperature, CO2 capture capacity, and kinetics with quantitative accuracy. The CFD modeling methodology and associated uncertainty quantification techniques presented herein offer a solid framework for estimating the predictive confidence in the virtual scale up of a larger carbon capture device.
When dealing with nuclear reactor calculation schemes, the need for 3D transport-based reference solutions is essential for validation and optimization purposes. As SN transport method may be considered promising with respect to comprehensive parallel computations, a 3D full PWR core benchmark was proposed to challenge the capabilities of the PENTRAN parallel SN code utilizing an IBM-BG/P computer. After a brief description of the benchmark, a parallel performance analysis is carried out, and shows that the parallelizable (Amdahl) fraction of PENTRAN is comprised between 0.994 ≤ f ≤ 0.996 for a number of BG/P nodes ranging from 17 to 1156. The associated speedup reaches a value greater than 200 with 1156 nodes. Using a best estimate model, PENTRAN results are then compared to Monte Carlo results rendered using the MCNP5 code. Good consistency is observed between the two methods (SN and Monte Carlo), with discrepancies less than 65 pcm for the keff, and less than 2.5% for the flux at the pincell level. (author)
A computational fluid dynamics (CFD) model for predicting the moderator circulation inside the Canada deuterium uranium (CANDU) reactor vessel has been developed to estimate the local subcooling of the moderator in the vicinity of the Calandria tubes. The buoyancy effect induced by internal heating is accounted for by Boussinesq approximation. The standard k-[curly epsilon] turbulence model associated with logarithmic wall treatment is applied to predict the turbulent jet flows from the inlet nozzles. The matrix of the Calandria tubes in the core region is simplified to porous media, in which anisotropic hydraulic impedance is modeled using an empirical correlation of the frictional pressure loss. The governing equations are solved by CFX-4.4, a commercial CFD code developed by AEA Technology. The CFD model has been successfully verified and validated against experimental data obtained at Stern Laboratories Inc. in Hamilton, Ontario, Canada
OʼLeary, Donal Peter
2012-09-01
Pneumatic nail guns are a tool used commonly in the construction industry and are widely available. Accidental injuries from nail guns are common, and several cases of suicide using a nail gun have been reported. Computed tomographic (CT) imaging, together with echocardiography, has been shown to be the gold standard for investigation of these cases. We present a case of a 55-year-old man who presented to the accident and emergency unit of a community hospital following an accidental pneumatic nail gun injury to his thorax. Volume-rendered CT of the thorax allowed an accurate assessment of the thoracic injuries sustained by this patient. As there was no evidence of any acute life-threatening injury, a sternotomy was avoided and the patient was observed closely until discharge. In conclusion, volume-rendered 3-dimensional CT can greatly help in the decision to avoid an unnecessary sternotomy in patients with a thoracic nail gun injury.
Lindsey, Patricia F.
1994-01-01
In microgravity conditions mobility is greatly enhanced and body stability is difficult to achieve. Because of these difficulties, optimum placement and accessibility of objects and controls can be critical to required tasks on board shuttle flights or on the proposed space station. Anthropometric measurement of the maximum reach of occupants of a microgravity environment provide knowledge about maximum functional placement for tasking situations. Calculations for a full body, functional reach envelope for microgravity environments are imperative. To this end, three dimensional computer modeled human figures, providing a method of anthropometric measurement, were used to locate the data points that define the full body, functional reach envelope. Virtual reality technology was utilized to enable an occupant of the microgravity environment to experience movement within the reach envelope while immersed in a simulated microgravity environment.
Soerensen, Niels N.
2009-07-15
The report describes the application of the correlation based transition model of Menter et. al. [1, 2] to the cylinder drag crisis and the stalled flow over an DU-96-W-351 airfoil using the DES methodology. When predicting the flow over airfoils and rotors, the laminar-turbulent transition process can be important for the aerodynamic performance. Today, the most widespread approach is to use fully turbulent computations, where the transitional process is ignored and the entire boundary layer on the wings or airfoils is handled by the turbulence model. The correlation based transition model has lately shown promising results, and the present paper describes the application of the model to predict the drag and shedding frequency for flow around a cylinder from sub to super-critical Reynolds numbers. Additionally, the model is applied to the flow around the DU-96 airfoil, at high angles of attack. (au)
Saho, Tatsunori; Onishi, Hideo
2015-07-01
In this study, we evaluated hemodynamics using simulated models and determined how cerebral aneurysms develop in simulated and patient-specific models based on medical images. Computational fluid dynamics (CFD) was analyzed by use of OpenFOAM software. Flow velocity, stream line, and wall shear stress (WSS) were evaluated in a simulated model aneurysm with known geometry and in a three-dimensional angiographic model. The ratio of WSS at the aneurysm compared with that at the basilar artery was 1:10 in simulated model aneurysms with a diameter of 10 mm and 1:18 in the angiographic model, indicating similar tendencies. Vortex flow occurred in both model aneurysms, and the WSS decreased in larger model aneurysms. The angiographic model provided accurate CFD information, and the tendencies of simulated and angiographic models were similar. These findings indicate that hemodynamic effects are involved in the development of aneurysms. PMID:25911446
The dark silicon problem, which limits the power-growth of future computer generations, is interpreted as a heat energy transport problem when increasing the energy emitting surface area within a given volume. A comparison of two 3D-configuration models, namely a standard slicing and a fractal surface generation within the Menger sponge geometry is presented. In the following it is shown, that for iteration orders n>3 the fractal model shows increasingly better thermal behavior. As a consequence cooling problems may be minimized by using a fractal architecture. Therefore the Menger sponge geometry is a good example for fractal architectures applicable not only in computer science, but also e.g. in chemistry when building chemical reactors, optimizing catalytic processes or in sensor construction technology building highly effective sensors for toxic gases or water analysis
Collon-Drouaillet, Pauline; Henrion, Vincent; Pellerin, Jeanne
2012-01-01
International audience This paper presents a method to stochastically simulate 3D karstic networks and more specifically branchwork pattern cave systems. Considering that they can be compared with 3D fluvial networks, the topological classification of Strahler and the corresponding ratios of Horton are used to define three morphometric parameters. These parameters are integrated in an algorithm that computes branches hierarchically to obtain a final network organized around the main observ...
The AP1000 is an 1100 MWe advanced nuclear power plant that uses passive safety features to enhance plant safety and to provide significant and measurable improvements in plant simplification, reliability, investment protection and plant costs. The AP1000 received final design approval from the US-NRC in 2004. The AP1000 design is based on the AP600 design that received final design approval in 1999. Wherever possible, the AP1000 plant configuration and layout was kept the same as AP600 to take advantage of the maturity of the design and to minimize new design efforts. As a result, the two-loop configuration was maintained for AP1000, and the containment vessel diameter was kept the same. It was determined that this significant power up-rate was well within the capability of the passive safety features, and that the safety margins for AP1000 were greater than those of operating PWRs. A key feature of the passive core cooling system is the passive residual heat removal heat exchanger (PRHR HX) that provides decay heat removal for postulated LOCA and non-LOCA events. The PRHR HX is a C-tube heat exchanger located in the in-containment refueling water storage tank (IRWST) above the core promoting natural circulation heat removal between the reactor cooling system and the tank. Component testing was performed for the AP600 PRHR HX to determine the heat transfer characteristics and to develop correlations to be used for the AP1000 safety analysis codes. The data from these tests were confirmed by subsequent integral tests at three separate facilities including the ROSA facility in Japan. Owing to the importance of this component, an independent analysis has been performed using the ATHOS-based computational fluid dynamics computer code PRHRCFD. Two separate models of the PRHR HX and IRWST have been developed representing the ROSA test geometry and the AP1000 plant geometry. Confirmation of the ROSA test results were used to validate PRHRCFD, and the AP1000 plant model
Stegmaier Philip
2010-05-01
Full Text Available Abstract Background Knowledge of transcription factor-DNA binding patterns is crucial for understanding gene transcription. Numerous DNA-binding proteins are annotated as transcription factors in the literature, however, for many of them the corresponding DNA-binding motifs remain uncharacterized. Results The position weight matrices (PWMs of transcription factors from different structural classes have been determined using a knowledge-based statistical potential. The scoring function calibrated against crystallographic data on protein-DNA contacts recovered PWMs of various members of widely studied transcription factor families such as p53 and NF-κB. Where it was possible, extensive comparison to experimental binding affinity data and other physical models was made. Although the p50p50, p50RelB, and p50p65 dimers belong to the same family, particular differences in their PWMs were detected, thereby suggesting possibly different in vivo binding modes. The PWMs of p63 and p73 were computed on the basis of homology modeling and their performance was studied using upstream sequences of 85 p53/p73-regulated human genes. Interestingly, about half of the p63 and p73 hits reported by the Match algorithm in the altogether 126 promoters lay more than 2 kb upstream of the corresponding transcription start sites, which deviates from the common assumption that most regulatory sites are located more proximal to the TSS. The fact that in most of the cases the binding sites of p63 and p73 did not overlap with the p53 sites suggests that p63 and p73 could influence the p53 transcriptional activity cooperatively. The newly computed p50p50 PWM recovered 5 more experimental binding sites than the corresponding TRANSFAC matrix, while both PWMs showed comparable receiver operator characteristics. Conclusions A novel algorithm was developed to calculate position weight matrices from protein-DNA complex structures. The proposed algorithm was extensively validated
无
2002-01-01
This paper presents a principle and a method of col or 3D laser scanning measurement. Based on the fundamental monochrome 3D measureme nt study, color information capture, color texture mapping, coordinate computati on and other techniques are performed to achieve color 3D measurement. The syste m is designed and composed of a line laser light emitter, one color CCD camera, a motor-driven rotary filter, a circuit card and a computer. Two steps in captu ring object's images in the measurement process: Firs...
To evaluate the diagnostic performance of automated coronary atherosclerotic plaque quantification (QCT) by different users (expert/non-expert/automatic). One hundred fifty coronary artery segments from 142 patients who underwent coronary computed tomography angiography (CCTA) and intravascular ultrasound (IVUS) were analyzed. Minimal lumen area (MLA), maximal lumen area stenosis percentage (%AS), mean plaque burden percentage (%PB), and plaque volume were measured semi-automatically by expert, non-expert, and fully automatic QCT analyses, and then compared to IVUS. Between IVUS and expert QCT analysis, the correlation coefficients (r) for the MLA, %AS, %PB, and plaque volume were excellent: 0.89 (p < 0.001), 0.84 (p < 0.001), 0.91 (p < 0.001), and 0.94 (p < 0.001), respectively. There were no significant differences in the mean parameters (all p values >0.05) except %AS (p = 0.01). The automatic QCT analysis showed comparable performance to non-expert QCT analysis, showing correlation coefficients (r) of the MLA (0.80 vs. 0.82), %AS (0.82 vs. 0.80), %PB (0.84 vs. 0.73), and plaque volume (0.84 vs. 0.79) when they were compared to IVUS, respectively. Fully automatic QCT analysis showed clinical utility compared with IVUS, as well as a compelling performance when compared with semiautomatic analyses. (orig.)
Makoto YAMAMOTO; Junichi IKEDA; Kazuaki INABA
2006-01-01
Recently, a number of environmental problems caused from fossil fuel combustion have been focused on. In addition, with the eventual depletion of fossil energy resources, hydrogen gas is expected to be an alternative energy resource in the near future. It is characterized by high energy per unit weight, high reaction rate, wide range of flammability and the low emission property. On the other hand, many researches have been underway in several countries to improve a propulsion system for an advanced aircraft. The system is required to have higher power, lighter weight and lower emissions than existing ones. In such a future propulsion system, hydrogen gas would be one of the promising fuels for realizing the requirements. Considering these backgrounds, our group has proposed a new cycle concept for hydrogen-fueled aircraft propulsion system. In the present study, we perform 3dimensional computations of turbulent flow fields with hydrogen-fueled combustion around a turbine blade. The main objective is to clarify the influence of arrangement of hydrogen injector holes. Changing the chordwise and spanwise spacings of the holes, the 3 dimensional nature of the flow and thermal fields is numerically studied.
Park, Hyung-Bok [Yonsei University Health System, Yonsei-Cedar Sinai Integrative Cardiovascular Imaging Research Center, Seoul (Korea, Republic of); Myongji Hospital, Division of Cardiology, Cardiovascular Center, Goyang (Korea, Republic of); Lee, Byoung Kwon [Yonsei University College of Medicine, Division of Cardiology, Gangnam Severance Hospital, Seoul (Korea, Republic of); Shin, Sanghoon [Yonsei University Health System, Yonsei-Cedar Sinai Integrative Cardiovascular Imaging Research Center, Seoul (Korea, Republic of); National Health Insurance Corporation Ilsan Hospital, Division of Cardiology, Goyang (Korea, Republic of); Heo, Ran; Chang, Hyuk-Jae; Chung, Namsik [Yonsei University Health System, Yonsei-Cedar Sinai Integrative Cardiovascular Imaging Research Center, Seoul (Korea, Republic of); Yonsei University Health System, Division of Cardiology, Severance Cardiovascular Hospital, Seoul (Korea, Republic of); Arsanjani, Reza [Cedars-Sinai Medical Center, Departments of Imaging and Medicine, Cedars-Sinai Heart Institute, Los Angeles, CA (United States); Kitslaar, Pieter H. [Leiden University Medical Center, Department of Radiology, Division of Image Processing, Leiden (Netherlands); Medis medical Imaging Systems B.V., Leiden (Netherlands); Broersen, Alexander; Dijkstra, Jouke [Leiden University Medical Center, Department of Radiology, Division of Image Processing, Leiden (Netherlands); Ahn, Sung Gyun [Yonsei University Wonju Severance Christian Hospital, Division of Cardiology, Wonju (Korea, Republic of); Min, James K. [New York-Presbyterian Hospital, Institute for Cardiovascular Imaging, Weill-Cornell Medical College, New York, NY (United States); Hong, Myeong-Ki; Jang, Yangsoo [Yonsei University Health System, Division of Cardiology, Severance Cardiovascular Hospital, Seoul (Korea, Republic of)
2015-10-15
To evaluate the diagnostic performance of automated coronary atherosclerotic plaque quantification (QCT) by different users (expert/non-expert/automatic). One hundred fifty coronary artery segments from 142 patients who underwent coronary computed tomography angiography (CCTA) and intravascular ultrasound (IVUS) were analyzed. Minimal lumen area (MLA), maximal lumen area stenosis percentage (%AS), mean plaque burden percentage (%PB), and plaque volume were measured semi-automatically by expert, non-expert, and fully automatic QCT analyses, and then compared to IVUS. Between IVUS and expert QCT analysis, the correlation coefficients (r) for the MLA, %AS, %PB, and plaque volume were excellent: 0.89 (p < 0.001), 0.84 (p < 0.001), 0.91 (p < 0.001), and 0.94 (p < 0.001), respectively. There were no significant differences in the mean parameters (all p values >0.05) except %AS (p = 0.01). The automatic QCT analysis showed comparable performance to non-expert QCT analysis, showing correlation coefficients (r) of the MLA (0.80 vs. 0.82), %AS (0.82 vs. 0.80), %PB (0.84 vs. 0.73), and plaque volume (0.84 vs. 0.79) when they were compared to IVUS, respectively. Fully automatic QCT analysis showed clinical utility compared with IVUS, as well as a compelling performance when compared with semiautomatic analyses. (orig.)
Rafsanjani, Ahmad; Wittel, Falk K; Carmeliet, Jan
2015-01-01
The hygro-mechanical behavior of a hierarchical cellular material, i.e. growth rings of softwood is investigated using a two-scale micro-mechanics model based on a computational homogenization technique. The lower scale considers the individual wood cells of varying geometry and dimensions. Honeycomb unit cells with periodic boundary conditions are utilized to calculate the mechanical properties and swelling coefficients of wood cells. Using the cellular scale results, the anisotropy in mechanical and swelling behavior of a growth ring in transverse directions is investigated. Predicted results are found to be comparable to experimental data. It is found that the orthotropic swelling properties of the cell wall in thin-walled earlywood cells produce anisotropic swelling behavior while, in thick latewood cells, this anisotropy vanishes. The proposed approach provides the ability to consider the complex microstructure when predicting the effective mechanical and swelling properties of softwood.
Multifractal modelling and 3D lacunarity analysis
This study presents a comparative evaluation of lacunarity of 3D grey level models with different types of inhomogeneity. A new method based on the 'Relative Differential Box Counting' was developed to estimate the lacunarity features of grey level volumes. To validate our method, we generated a set of 3D grey level multifractal models with random, anisotropic and hierarchical properties. Our method gives a lacunarity measurement correlated with the theoretical one and allows a better model classification compared with a classical approach.
D. Pletinckx
2012-09-01
Full Text Available The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.
Pannala, S; D' Azevedo, E; Zacharia, T
2002-02-26
The goal of the radiation modeling effort was to develop and implement a radiation algorithm that is fast and accurate for the underhood environment. As part of this CRADA, a net-radiation model was chosen to simulate radiative heat transfer in an underhood of a car. The assumptions (diffuse-gray and uniform radiative properties in each element) reduce the problem tremendously and all the view factors for radiation thermal calculations can be calculated once and for all at the beginning of the simulation. The cost for online integration of heat exchanges due to radiation is found to be less than 15% of the baseline CHAD code and thus very manageable. The off-line view factor calculation is constructed to be very modular and has been completely integrated to read CHAD grid files and the output from this code can be read into the latest version of CHAD. Further integration has to be performed to accomplish the same with STAR-CD. The main outcome of this effort is to obtain a highly scalable and portable simulation capability to model view factors for underhood environment (for e.g. a view factor calculation which took 14 hours on a single processor only took 14 minutes on 64 processors). The code has also been validated using a simple test case where analytical solutions are available. This simulation capability gives underhood designers in the automotive companies the ability to account for thermal radiation - which usually is critical in the underhood environment and also turns out to be one of the most computationally expensive components of underhood simulations. This report starts off with the original work plan as elucidated in the proposal in section B. This is followed by Technical work plan to accomplish the goals of the project in section C. In section D, background to the current work is provided with references to the previous efforts this project leverages on. The results are discussed in section 1E. This report ends with conclusions and future scope of
This book explains modeling of solid works 3D and application of 3D CAD/CAM. The contents of this book are outline of modeling such as CAD and 2D and 3D, solid works composition, method of sketch, writing measurement fixing, selecting projection, choosing condition of restriction, practice of sketch, making parts, reforming parts, modeling 3D, revising 3D modeling, using pattern function, modeling necessaries, assembling, floor plan, 3D modeling method, practice floor plans for industrial engineer data aided manufacturing, processing of CAD/CAM interface.
Kapur, Tina; Pieper, Steve; Fedorov, Andriy; Fillion-Robin, J-C; Halle, Michael; O'Donnell, Lauren; Lasso, Andras; Ungi, Tamas; Pinter, Csaba; Finet, Julien; Pujol, Sonia; Jagadeesan, Jayender; Tokuda, Junichi; Norton, Isaiah; Estepar, Raul San Jose; Gering, David; Aerts, Hugo J W L; Jakab, Marianna; Hata, Nobuhiko; Ibanez, Luiz; Blezek, Daniel; Miller, Jim; Aylward, Stephen; Grimson, W Eric L; Fichtinger, Gabor; Wells, William M; Lorensen, William E; Schroeder, Will; Kikinis, Ron
2016-10-01
The National Alliance for Medical Image Computing (NA-MIC) was launched in 2004 with the goal of investigating and developing an open source software infrastructure for the extraction of information and knowledge from medical images using computational methods. Several leading research and engineering groups participated in this effort that was funded by the US National Institutes of Health through a variety of infrastructure grants. This effort transformed 3D Slicer from an internal, Boston-based, academic research software application into a professionally maintained, robust, open source platform with an international leadership and developer and user communities. Critical improvements to the widely used underlying open source libraries and tools-VTK, ITK, CMake, CDash, DCMTK-were an additional consequence of this effort. This project has contributed to close to a thousand peer-reviewed publications and a growing portfolio of US and international funded efforts expanding the use of these tools in new medical computing applications every year. In this editorial, we discuss what we believe are gaps in the way medical image computing is pursued today; how a well-executed research platform can enable discovery, innovation and reproducible science ("Open Science"); and how our quest to build such a software platform has evolved into a productive and rewarding social engineering exercise in building an open-access community with a shared vision. PMID:27498015
I. V. Kachanov
2015-01-01
Full Text Available The modern development of industrial production is closely connected with the use of science-based and high technologies to ensure competitiveness of the manufactured products on the world market. There is also much tension around an energy- and resource saving problem which can be solved while introducing new technological processes and creation of new materials that provide productivity increase through automation and improvement of tool life. Development and implementation of such technologies are rather often considered as time-consuming processes which are connected with complex calculations and experimental investigations. Implementation of a simulation modelling for materials processing using modern software products serves an alternative to experimental and theoretical methods of research.The aim of this paper is to compare experimental results while obtaining bimetallic samples of a forming tool through the method of speed hot extrusion and the results obtained with the help of computer simulation using DEFORM-3D package and a finite element method. Comparative analysis of plastic flow of real and model samples has shown that the obtained models provide high-quality and reliable picture of plastic flow during high-speed hot extrusion. Modeling in DEFORM-3D make it possible to eliminate complex calculations and significantly reduce a number of experimental studies while developing new technological processes.
This work contains description of the physical and mathematical basis on which the IVA3 computer code relies. After describing the state of the art of the 3D modeling for transient multiphase flows, the model assumptions and the modeling technique used in IVA3 are described. Starting with the principles of conservation of mass, momentum, and energy, the non averaged conservation equations are derived for each of the velocity fields which consist of different isothermal components. Thereafter averaging is applied and the working form of the system of 21 partial differential equations is derived. Special attention is paid to the strict consistence of the modeling technique used in IVA3 with the second principle of thermodynamics. The entropy concept used is derived starting with the unaveraged conservation equations and subsequent averaging. The source terms of the entropy production are carefully defined and the final form of the averaged entropy equation is given ready for direct practical applications. The idea of strong analytical thermodynamic coupling between pressure field and changes of the other thermodynamic properties, which is used for the first time in 3D multi fluid modeling, is presented in detail. After obtaining the working form of the conservation equations, the discretization procedure and the reduction to algebraic problems is presented. The mathematical solution method together with some information about the architecture of IVA3 including the local momentum decoupling and accuracy control is presented too. (orig./GL)
Suri Moonsamy
2014-04-01
Full Text Available Using integrated in-silico computational techniques, including homology modeling, structure-based and pharmacophore-based virtual screening, molecular dynamic simulations, per-residue energy decomposition analysis and atom-based 3D-QSAR analysis, we proposed ten novel compounds as potential CCR5-dependent HIV-1 entry inhibitors. Via validated docking calculations, binding free energies revealed that novel leads demonstrated better binding affinities with CCR5 compared to maraviroc, an FDA-approved HIV-1 entry inhibitor and in clinical use. Per-residue interaction energy decomposition analysis on the averaged MD structure showed that hydrophobic active residues Trp86, Tyr89 and Tyr108 contributed the most to inhibitor binding. The validated 3D-QSAR model showed a high cross-validated rcv2 value of 0.84 using three principal components and non-cross-validated r2 value of 0.941. It was also revealed that almost all compounds in the test set and training set yielded a good predicted value. Information gained from this study could shed light on the activity of a new series of lead compounds as potential HIV entry inhibitors and serve as a powerful tool in the drug design and development machinery.
C Hann; M Bentley; A Vercnocke; E Ritman; M Fautsch
2011-12-31
The site of outflow resistance leading to elevated intraocular pressure in primary open-angle glaucoma is believed to be located in the region of Schlemm's canal inner wall endothelium, its basement membrane and the adjacent juxtacanalicular tissue. Evidence also suggests collector channels and intrascleral vessels may have a role in intraocular pressure in both normal and glaucoma eyes. Traditional imaging modalities limit the ability to view both proximal and distal portions of the trabecular outflow pathway as a single unit. In this study, we examined the effectiveness of three-dimensional micro-computed tomography (3D micro-CT) as a potential method to view the trabecular outflow pathway. Two normal human eyes were used: one immersion fixed in 4% paraformaldehyde and one with anterior chamber perfusion at 10 mmHg followed by perfusion fixation in 4% paraformaldehyde/2% glutaraldehyde. Both eyes were postfixed in 1% osmium tetroxide and scanned with 3D micro-CT at 2 {mu}m or 5 {mu}m voxel resolution. In the immersion fixed eye, 24 collector channels were identified with an average orifice size of 27.5 {+-} 5 {mu}m. In comparison, the perfusion fixed eye had 29 collector channels with a mean orifice size of 40.5 {+-} 13 {mu}m. Collector channels were not evenly dispersed around the circumference of the eye. There was no significant difference in the length of Schlemm's canal in the immersed versus the perfused eye (33.2 versus 35.1 mm). Structures, locations and size measurements identified by 3D micro-CT were confirmed by correlative light microscopy. These findings confirm 3D micro-CT can be used effectively for the non-invasive examination of the trabecular meshwork, Schlemm's canal, collector channels and intrascleral vasculature that comprise the distal outflow pathway. This imaging modality will be useful for non-invasive study of the role of the trabecular outflow pathway as a whole unit.
Micromechanics of hierarchical materials
Mishnaevsky, Leon, Jr.
2012-01-01
nanoengineered matrix, fiber bundle model of UD composites with hierarchically clustered fibers and 3D multilevel model of wood considered as a gradient, cellular material with layered composite cell walls. The main areas of research in micromechanics of hierarchical materials are identified, among them, the...
Tramm, John R.; Gunow, Geoffrey; He, Tim; Smith, Kord S.; Forget, Benoit; Siegel, Andrew R.
2016-05-01
In this study we present and analyze a formulation of the 3D Method of Characteristics (MOC) technique applied to the simulation of full core nuclear reactors. Key features of the algorithm include a task-based parallelism model that allows independent MOC tracks to be assigned to threads dynamically, ensuring load balancing, and a wide vectorizable inner loop that takes advantage of modern SIMD computer architectures. The algorithm is implemented in a set of highly optimized proxy applications in order to investigate its performance characteristics on CPU, GPU, and Intel Xeon Phi architectures. Speed, power, and hardware cost efficiencies are compared. Additionally, performance bottlenecks are identified for each architecture in order to determine the prospects for continued scalability of the algorithm on next generation HPC architectures.
JAC3D is a three-dimensional finite element program designed to solve quasi-static nonlinear mechanics problems. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. A nonlinear conjugate gradient method is used to solve the equation. The method is implemented in a three-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. An eight-node Lagrangian uniform strain element is used with hourglass stiffness to control the zero-energy modes. This report documents the elastic and isothermal elastic-plastic material model. Other material models, documented elsewhere, are also available. The program is vectorized for efficient performance on Cray computers. Sample problems described are the bending of a thin beam, the rotation of a unit cube, and the pressurization and thermal loading of a hollow sphere
This paper describes a new inverse analysis system using the hierarchical (multilayer) neural networks and the computational mechanics. The present inverse analysis basically consists of the following three subprocesses: by parametrically varying system parameters, their corresponding responses of the system are calculated through computational mechanics simulations, each of which is an ordinary direct analysis. Each data pair of system parameters system responses is called training pattern; the back-propagation neural network is iteratively trained using a number of training patterns. The system responses are given to the input units of the network, while the system parameters to be identified are given to its output units as teacher signal; some system responses measured are given to the well trained network, which immediately outputs appropriate system parameters even for untrained patterns. This is an inverse analysis. To demonstrate its practical performances, the present system is applied to identify locations and shapes of two adjacent dissimilar surface cracks hidden in a pipe with the electric potential drop method. The results clearly show that the present system is very efficient and accurate. (author). 7 refs., 10 figs
Brounstein, Anna; Hacihaliloglu, Ilker; Guy, Pierre; Hodgson, Antony; Abugharbieh, Rafeef
2015-12-01
Automatic, accurate and real-time registration is an important step in providing effective guidance and successful anatomic restoration in ultrasound (US)-based computer assisted orthopedic surgery. We propose a method in which local phase-based bone surfaces, extracted from intra-operative US data, are registered to pre-operatively segmented computed tomography data. Extracted bone surfaces are downsampled and reinforced with high curvature features. A novel hierarchical simplification algorithm is used to further optimize the point clouds. The final point clouds are represented as Gaussian mixture models and iteratively matched by minimizing the dissimilarity between them using an L2 metric. For 44 clinical data sets from 25 pelvic fracture patients and 49 phantom data sets, we report mean surface registration accuracies of 0.31 and 0.77 mm, respectively, with an average registration time of 1.41 s. Our results suggest the viability and potential of the chosen method for real-time intra-operative registration in orthopedic surgery. PMID:26365924
Preece, Daniel; Williams, Sarah B.; Lam, Richard; Weller, Renate
2013-01-01
Three-dimensional (3D) information plays an important part in medical and veterinary education. Appreciating complex 3D spatial relationships requires a strong foundational understanding of anatomy and mental 3D visualization skills. Novel learning resources have been introduced to anatomy training to achieve this. Objective evaluation of their…
3d-3d correspondence revisited
Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr
2016-04-01
In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.
Highlights: • Technical and functional analysis of the Albolafia waterwheel (Córdoba, Spain). • Spatial distribution of speeds using computational-fluid dynamics simulation (CFD). • Finite-element analysis (FEA) of the waterwheel. • Dynamic simulation of the waterwheel using Computer-Aided Engineering (CAE) techniques. • Validation of the operation of the waterwheel. - Abstract: A detailed study has been made of a vertical waterwheel, the wheel of Albolafia situated on the Guadalquivir river near the city of Cordoba (Spain). We propose a methodology for ad hoc research based on three aspects: 3D geometric modeling, analysis with computational fluid-dynamics techniques and dynamic simulation of the whole and its finite-element analysis. The results show the correct operation of the waterwheel with an initial moment of inertia of 90,800 N m and a range of water-flow speeds of between 0.91 and 1.01 m/s. These values are related to the average flow of the river, which allowed the wheel to operate at least 124 days per year. The spatial distribution of stresses has shown that the full buckets created an imbalance compared with the empty ones, and that the star-shaped polygon reinforcement effectively absorbed these tensions. In addition, the oak wood used in the construction of the waterwheel proved highly resistant, as the maximum working stress has never been surpassed, reflecting the effectiveness of the materials used at the time
NIF Ignition Target 3D Point Design
Jones, O; Marinak, M; Milovich, J; Callahan, D
2008-11-05
We have developed an input file for running 3D NIF hohlraums that is optimized such that it can be run in 1-2 days on parallel computers. We have incorporated increasing levels of automation into the 3D input file: (1) Configuration controlled input files; (2) Common file for 2D and 3D, different types of capsules (symcap, etc.); and (3) Can obtain target dimensions, laser pulse, and diagnostics settings automatically from NIF Campaign Management Tool. Using 3D Hydra calculations to investigate different problems: (1) Intrinsic 3D asymmetry; (2) Tolerance to nonideal 3D effects (e.g. laser power balance, pointing errors); and (3) Synthetic diagnostics.
Wook-Jin Choi
2013-01-01
Full Text Available A computer-aided detection (CAD system is helpful for radiologists to detect pulmonary nodules at an early stage. In this paper, we propose a novel pulmonary nodule detection method based on hierarchical block classification. The proposed CAD system consists of three steps. In the first step, input computed tomography images are split into three-dimensional block images, and we apply entropy analysis on the block images to select informative blocks. In the second step, the selected block images are segmented and adjusted for detecting nodule candidates. In the last step, we classify the nodule candidate images into nodules and non-nodules. We extract feature vectors of the objects in the selected blocks. Lastly, the support vector machine is applied to classify the extracted feature vectors. Performance of the proposed system is evaluated on the Lung Image Database Consortium database. The proposed method has reduced the false positives in the nodule candidates significantly. It achieved 95.28% sensitivity with only 2.27 false positives per scan.
Parallel-Hierarchical Computing System for Multi-Level Transformation of Masked Digital Signals
YAROVYY, A. A.
2012-08-01
Full Text Available Paper deals with organization principles of parallel-hierarchical (PH transform for multistage perception and processing, compression and recognition of information in computational systems which make use of computational scheme similar to neural. Unified methodological approach was developed for analysis of parallel processes. This approach considers influence of structural hierarchy in dynamics. It tracks processes of spatial areas transformation of correlated and generation of uncorrelated in time elements of generated PH network, at the time of transition of the network from one stable stage to another. The main feature of the proposed method is the studying of the dynamics of spatial-correlated procedure for transformation between current and output units in PH network. This procedure gives an opportunity to present processing in PH network as the process of parallel-sequential transformation of diverse image components and consideration of temporal characteristics of transformation. The features analysis of structural-functional organization of networking model of PH transformation of the information environments and corresponding masks generation methods is realized in the given research. On the base of research carried out the method of optimized masks formation while information coding in PH transformation is proposed. The software package, characterized by increased efficiency of direct and reverse PH transformation is developed.
Brdnik, Lovro
2015-01-01
Diplomsko delo analizira trenutno stanje 3D tiskalnikov na trgu. Prikazan je razvoj in principi delovanja 3D tiskalnikov. Predstavljeni so tipi 3D tiskalnikov, njihove prednosti in slabosti. Podrobneje je predstavljena zgradba in delovanje koračnih motorjev. Opravljene so meritve koračnih motorjev. Opisana je programska oprema za rokovanje s 3D tiskalniki in komponente, ki jih potrebujemo za izdelavo. Diploma se oklepa vprašanja, ali je izdelava 3D tiskalnika bolj ekonomična kot pa naložba v ...
Plane 3D effect display based on computer vision%基于计算机视觉的平面3D效果显示
阚洪
2016-01-01
The 3D display technology is the research hotpot of current computer graphic image technology,and high atten⁃tion is paid to realization of its true vision experience on the plane. In order to promote the 3D experience of users,a 3D display based on computer vision is presented,which can eliminate the reflected light interference from human eyes by means of Win⁃dows operation system,infrared image acquisition device operated by OpenCV,and visible light filter. An efficient human pupil location algorithm is proposed,by which the approximate location of human eyes is determined through gray integral projection, and then the binary image is got with the optimized threshold segmentation method. On this basis,the morphological operation for the binary image is conducted to eliminate the noise and make the image processing easier. The algorithm combined corner detection based on OpenCV with ellipse fitting is used to locate the pupil,which is simple and efficient. The camera location is realized on the basis of cvCalibrateCamera function of OpenCV. Finally,the envisaged image of 3D display was accomplished with Bresenham line drawing method. To make the system have better real⁃time performance,the scanning area segmentation method and target area prediction method are used to reduce the system computing amount and realize fast tracking of human eyes.%3D显示技术作为当前计算机图形图像技术的研究热点，以其在平面上实现真实的视觉体验而获得高度重视。为了提升用户的3D体验，提出了一种基于计算机视觉的3D显示器。借助于Windows操作系统，通过OpenCV操作红外图像采集设备，搭配可见光滤光镜，消除了人眼反射光的干扰。提出了一种比较高效的人类瞳孔定位算法，首先利用灰度积分投影将人眼的大概位置确定，之后使用优化的阈值分割方法得到二值图像，在此基础上对其进行形态学运算去除噪声，使图像更易处理。
使用计算机视觉的3D模型动作记录器%3D Model Action Recording System Using Computer Visions
丁志远
2013-01-01
该文旨在完成一款基于计算机视觉的3D模型动作记录器，即计算机通过摄像头获取人体运动视频并检测跟踪，之后通过处理数据控制3D模型，从而将人体动作进行记录保存。文章主要围绕运动目标检测、运动目标跟踪和3D建模三个方面展开研究。运动目标检测方面使用OpenCV(Open Source Computer Vision Library)提供的背景差分算法对目标进行分析并提取差分元素；运动目标跟踪方面则研究了常用的Camshift跟踪算法，实现对运动目标的连续跟踪以及识别从而保证动作记录器的连贯性；3D建模部分则使用3Dmax进行建立模型以及骨骼动画的制作处理，并使用Ogremax导出模型；而模型的骨骼动画则由OGRE导入测试环境并根据之前的处理结果进行相应的控制，从而实现人体运动的动作记录。%This paper present a 3D model action recording system using computer visions. A computer captures human motion videos with a network camera and conduct further detection and tracking of the video resources, then a 3D model was created based on the recorded data results. The action recording system includes motion target detection, motion target tracking and 3D modeling. OpenCV is used in the motion target detection where background image difference algorithm is used to analyze the moving target and extract different elements. For the motion target tracking, the Camshift tracking algorithm is used to realize continuous tracking and recognition of moving objects and ensure good performance of the action recorder. In our implementa-tion, 3Dmax is used to build the 3D model and skeletal animations, where Ogremax is used to export models, and then to im-port the skeletal animations into the test enviroment. The evaluations show that our motion recognition and recording system has good performance in one aspect, and can obtain accurate result on the other aspect.
Garcia, Dorian; Orteu, Jean-José; Robert, Laurent; Wattrisse, Bertrand; Bugarin, Florian
2013-01-01
Stereo digital image correlation (also called 3D DIC) is a common measurement technique in experimental mechanics for measuring 3D shapes or 3D displacement/strain fields, in research laboratories as well as in industry. Nevertheless, like most of the optical full-field measurement techniques, 3D DIC suffers from a lack of information about its metrological performances. For the 3D DIC technique to be fully accepted as a standard measurement technique it is of key importance to assess its mea...
Cahn, D.F.; Murano, C.V.
1980-05-01
An interactive computer graphical display program was developed as an aid to user visualization and manipulation of hierarchically structured data systems such as thesauri. In the present configuration, a thesaurus term and its primary and secondary conceptual neighbors are presented to the user in tree graph form on a CRT; the user then designates, via light pen or keyboard, any of the neighbors as the next term of interest and receives a new display centered on this term. By successive specification of broader, narrower, and related terms, the user can course rapidly through the thesaurus space and refine his search file. At any stage, he deals with a term-centered, conceptually meaningful picture of a localized portion of the thesaurus, and is freed from the artificial difficulties of handling the traditional alphabetized thesaurus. Intentional limitation of the associative range of each display frame, and the use of color, case, and interconnecting vectors to encode relationships among terms, enhance interpretability of the display. Facile movement through the term space, provided by interactive computation, allows the display to remain simple, and is an essential element of the system. 3 figures.
Face Detection with a 3D Model
Barbu, Adrian; Lay, Nathan; Gramajo, Gary
2014-01-01
This paper presents a part-based face detection approach where the spatial relationship between the face parts is represented by a hidden 3D model with six parameters. The computational complexity of the search in the six dimensional pose space is addressed by proposing meaningful 3D pose candidates by image-based regression from detected face keypoint locations. The 3D pose candidates are evaluated using a parameter sensitive classifier based on difference features relative to the 3D pose. A...
Micromechanical analysis of nanocomposites using 3D voxel based material model
Mishnaevsky, Leon
2012-01-01
A computational study on the effect of nanocomposite structures on the elastic properties is carried out with the use of the 3D voxel based model of materials and the combined Voigt–Reuss method. A hierarchical voxel based model of a material reinforced by an array of exfoliated and intercalated ...... probability of glass fibers in hybrid (hierarchical) composites, using the micromechanical voxel-based model of nanocomposites, it was observed that the nanoreinforcement in the matrix leads to slightly lower fiber failure probability....
Mertens, J.C.E., E-mail: james.mertens@asu.edu; Williams, J.J., E-mail: jason.williams@asu.edu; Chawla, Nikhilesh, E-mail: nchawla@asu.edu
2014-06-01
The design and construction of a modular high resolution X-ray computed tomography (XCT) system is highlighted in this paper. The design approach is detailed for meeting a specified set of instrument performance goals tailored towards experimental versatility and high resolution imaging. The XCT tool is unique in the detector and X-ray source design configuration, enabling control in the balance between detection efficiency and spatial resolution. The system package is also unique: The sample manipulation approach implemented enables a wide gamut of in situ experimentation to analyze structure evolution under applied stimulus, by optimizing scan conditions through a high degree of controllability. The component selection and design process is detailed: Incorporated components are specified, custom designs are shared, and the approach for their integration into a fully functional XCT scanner is provided. Custom designs discussed include the dual-target X-ray source cradle which maintains position and trajectory of the beam between the two X-ray target configurations with respect to a scintillator mounting and positioning assembly and the imaging sensor, as well as a novel large-format X-ray detector with enhanced adaptability. The instrument is discussed from an operational point of view, including the details of data acquisition and processing implemented for 3D imaging via micro-CT. The performance of the instrument is demonstrated on a silica-glass particle/hydroxyl-terminated-polybutadiene (HTPB) matrix binder PBX simulant. Post-scan data processing, specifically segmentation of the sample's relevant microstructure from the 3D reconstruction, is provided to demonstrate the utility of the instrument. - Highlights: • Custom built X-ray tomography system for microstructural characterization • Detector design for maximizing polychromatic X-ray detection efficiency • X-ray design offered for maximizing X-ray flux with respect to imaging resolution
The design and construction of a modular high resolution X-ray computed tomography (XCT) system is highlighted in this paper. The design approach is detailed for meeting a specified set of instrument performance goals tailored towards experimental versatility and high resolution imaging. The XCT tool is unique in the detector and X-ray source design configuration, enabling control in the balance between detection efficiency and spatial resolution. The system package is also unique: The sample manipulation approach implemented enables a wide gamut of in situ experimentation to analyze structure evolution under applied stimulus, by optimizing scan conditions through a high degree of controllability. The component selection and design process is detailed: Incorporated components are specified, custom designs are shared, and the approach for their integration into a fully functional XCT scanner is provided. Custom designs discussed include the dual-target X-ray source cradle which maintains position and trajectory of the beam between the two X-ray target configurations with respect to a scintillator mounting and positioning assembly and the imaging sensor, as well as a novel large-format X-ray detector with enhanced adaptability. The instrument is discussed from an operational point of view, including the details of data acquisition and processing implemented for 3D imaging via micro-CT. The performance of the instrument is demonstrated on a silica-glass particle/hydroxyl-terminated-polybutadiene (HTPB) matrix binder PBX simulant. Post-scan data processing, specifically segmentation of the sample's relevant microstructure from the 3D reconstruction, is provided to demonstrate the utility of the instrument. - Highlights: • Custom built X-ray tomography system for microstructural characterization • Detector design for maximizing polychromatic X-ray detection efficiency • X-ray design offered for maximizing X-ray flux with respect to imaging resolution
Meulien Ohlmann, Odile
2013-02-01
Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?
The computer aided collimation gamma camera (CACAO in French) is a gamma camera using a collimator with large holes, a supplementary linear scanning motion during the acquisition and a dedicated reconstruction program taking full account of the source depth. The CACAO system was introduced to improve both the sensitivity and the resolution in nuclear medicine. This thesis focuses on the design of a fast and robust reconstruction algorithm in the CACAO project. We start by an overview of tomographic imaging techniques in nuclear medicine. After modelling the physical CACAO system, we present the complete reconstruction program which involves three steps: 1) shift and sum 2) deconvolution and filtering 3) rotation and sum. The deconvolution is the critical step that decreases the signal to noise ratio of the reconstructed images. We propose a regularized multi-channel algorithm to solve the deconvolution problem. We also present a fast algorithm based on Splines functions and preserving the high quality of the reconstructed images for the shift and the rotation steps. Comparisons of simulated reconstructed images in 2D and 3D for the conventional system (CPHC) and CACAO demonstrate the ability of CACAO system to increase the quality of the SPECT images. Finally, this study concludes with an experimental approach with a pixellated detector conceived for a 3D measurement of contaminated wounds. This experimentation proves the possible advantages of coupling the CACAO project with pixellated detectors. Moreover, a variety of applications could fully benefit from the CACAO system, such as low activity imaging, the use of high-energy gamma isotopes and the visualization of deep organs. Moreover the combination of the CACAO system with a pixels detector may open up further possibilities for the future of nuclear medicine. (author)
Turkot, Robert Bruce, Jr.
This dissertation is broken into two sections describing, first, a computer code simulating ion-surface interactions, VFTRIM3D, and, second, an experimental Langmuir probe analysis of a cylindrical SiOsb2 deposition system. VFTRIM3D is a 3-dimensional, Monte-Carlo, binary collision code employing fractal algorithms used to simulate atomic-scale surface roughness. This work applies this code to studies of incident ion energies in the 10's to 100's of eV on various targets and comparisons to experimental data prove its dependability for such simulations. The experimental portion of this thesis includes the development and investigation of a cylindrical SiOsb2 deposition system used to deposit gas permeation barrier thin films onto PET bottles. The plasma analysis is done utilizing time- and spatially resolved Langmuir probe techniques. In order to study the characteristics of the dielectric deposition plasma, a "hot" Langmuir probe was developed to acquire typical Langmuir probe data during SiOsb2 deposition. The SiOsb2 films deposited in this system are analyzed for their gas permeation qualities and are correlated to the plasma properties gathered using Langmuir probes as well as the gas, pressure, and time recipes used to produce them. It is found in this work that the application of SiOsb2 films onto flexible PET bottles using the fashion explained herein results in a decrease in the gas permeation characteristics of the SiOsb2-PET membrane as desired, but is found to be independent of the thickness of the SiOsb2 present. This limit is found to be caused by cracks and pinhole defects across the SiOsb2 film that permit uninhibited gas flow directly to the PET bottle.
Kim, Michael S; Bracken, John; Eshuis, Peter; Chen, S Y James; Fullerton, David; Cleveland, Joseph; Messenger, John C; Carroll, John D
2016-07-01
Determination of the coplanar view is a critical component of transcatheter aortic valve replacement (TAVR). The safety and accuracy of a novel reduced angular range C-arm computed tomography (CACT) approach coupled with a fully automated 3D analysis tool package to predict the coplanar view in TAVR was evaluated. Fifty-seven patients with severe symptomatic aortic stenosis deemed prohibitive-risk for surgery and who underwent TAVR were enrolled. Patients were randomized 2:1 to CACT vs. angiography (control) in estimating the coplanar view. These approaches to determine the coplanar view were compared quantitatively. Radiation doses needed to determine the coplanar view were recorded for both the CACT and control patients. Use of CACT offered good agreement with the actual angiographic view utilized during TAVR in 34 out of 41 cases in which a CACT scan was performed (83 %). For these 34 cases, the mean angular magnitude difference, taking into account both oblique and cranial/caudal angulation, was 1.3° ± 0.4°, while the maximum difference was 7.3°. There were no significant differences in the mean total radiation dose delivered to patients between the CACT and control groups as measured by either dose area product (207.8 ± 15.2 Gy cm(2) vs. 186.1 ± 25.3 Gy cm(2), P = 0.47) or air kerma (1287.6 ± 117.7 mGy vs. 1098.9 ± 143.8 mGy, P = 0.32). Use of reduced-angular range CACT coupled with fully automated 3D analysis tools is a safe, practical, and feasible method by which to determine the optimal angiographic deployment view for guiding TAVR procedures. PMID:27091735
Pathak, Ashish; Raessi, Mehdi
2014-11-01
We present a 3D MPI-parallel, GPU-accelerated computational tool that captures the interaction between a moving rigid body and two-fluid flows. Although the immediate application is the study of ocean wave energy converters (WECs), the model was developed at a general level and can be used in other applications. Solving the full Navier-Stokes equations, the model is able to capture non-linear effects, including wave-breaking and fluid-structure interaction, that have significant impact on WEC performance. To transport mass and momentum, we use a consistent scheme that can handle large density ratios (e.g. air/water). We present a novel reconstruction scheme for resolving three-phase (solid-liquid-gas) cells in the volume-of-fluid context, where the fluid interface orientation is estimated via a minimization procedure, while imposing a contact angle. The reconstruction allows for accurate mass and momentum transport in the vicinity of three-phase cells. The fast-fictitious-domain method is used for capturing the interaction between a moving rigid body and two-fluid flow. The pressure Poisson solver is accelerated using GPUs in the MPI framework. We present results of an array of test cases devised to assess the performance and accuracy of the computational tool.
Xiang Zhou
2014-02-01
Full Text Available As for the problem of how to carry out task scheduling and data replication effectively in the grid and to reduce task’s execution time, this thesis proposes the task scheduling algorithm and the optimum dynamic data replication algorithm and builds a scheme to effectively combine these two algorithms. First of all, the scheme adopts the ISS algorithm considering the number of tasks waiting queue, the location of task demand data and calculation capacity of site by adopting the method of network structure’s hierarchical scheduling to calculate the cost of comprehensive task with the proper weight efficiency and search out the best compute node area. And then the algorithm of ODHRA is adopted to analyze the data transmission time, memory access latency, waiting copy requests in the queue and the distance between nodes, choose out the best replications location in many copies combined with copy placement and copy management to reduce the file access time. The simulation results show that the proposed scheme compared with other algorithm has better performance in terms of average task execution time.
Molleda, Julio; Usamentiaga, Rubén; García, Daniel F.; Bulnes, Francisco G.
2011-03-01
Nowadays machine vision applications require skilled users to configure, tune, and maintain. Because such users are scarce, the robustness and reliability of applications are usually significantly affected. Autonomic computing offers a set of principles such as self-monitoring, self-regulation, and self-repair which can be used to partially overcome those problems. Systems which include self-monitoring observe their internal states, and extract features about them. Systems with self-regulation are capable of regulating their internal parameters to provide the best quality of service depending on the operational conditions and environment. Finally, self-repairing systems are able to detect anomalous working behavior and to provide strategies to deal with such conditions. Machine vision applications are the perfect field to apply autonomic computing techniques. This type of application has strong constraints on reliability and robustness, especially when working in industrial environments, and must provide accurate results even under changing conditions such as luminance, or noise. In order to exploit the autonomic approach of a machine vision application, we believe the architecture of the system must be designed using a set of orthogonal modules. In this paper, we describe how autonomic computing techniques can be applied to machine vision systems, using as an example a real application: 3D reconstruction in harsh industrial environments based on laser range finding. The application is based on modules with different responsibilities at three layers: image acquisition and processing (low level), monitoring (middle level) and supervision (high level). High level modules supervise the execution of low-level modules. Based on the information gathered by mid-level modules, they regulate low-level modules in order to optimize the global quality of service, and tune the module parameters based on operational conditions and on the environment. Regulation actions involve
Takebayashi Naoki
2007-07-01
Full Text Available Abstract Background Although testing for simultaneous divergence (vicariance across different population-pairs that span the same barrier to gene flow is of central importance to evolutionary biology, researchers often equate the gene tree and population/species tree thereby ignoring stochastic coalescent variance in their conclusions of temporal incongruence. In contrast to other available phylogeographic software packages, msBayes is the only one that analyses data from multiple species/population pairs under a hierarchical model. Results msBayes employs approximate Bayesian computation (ABC under a hierarchical coalescent model to test for simultaneous divergence (TSD in multiple co-distributed population-pairs. Simultaneous isolation is tested by estimating three hyper-parameters that characterize the degree of variability in divergence times across co-distributed population pairs while allowing for variation in various within population-pair demographic parameters (sub-parameters that can affect the coalescent. msBayes is a software package consisting of several C and R programs that are run with a Perl "front-end". Conclusion The method reasonably distinguishes simultaneous isolation from temporal incongruence in the divergence of co-distributed population pairs, even with sparse sampling of individuals. Because the estimate step is decoupled from the simulation step, one can rapidly evaluate different ABC acceptance/rejection conditions and the choice of summary statistics. Given the complex and idiosyncratic nature of testing multi-species biogeographic hypotheses, we envision msBayes as a powerful and flexible tool for tackling a wide array of difficult research questions that use population genetic data from multiple co-distributed species. The msBayes pipeline is available for download at http://msbayes.sourceforge.net/ under an open source license (GNU Public License. The msBayes pipeline is comprised of several C and R programs that
Midtgaard, Ole-Morten
1997-12-31
This thesis considers the feasibility of doing calculations to optimize electrical machines without the need to build expensive prototypes. It deals with the construction and assessment of new, hierarchical, hexahedral edge elements for three-dimensional computations of eddy currents with the electric vector potential formulation. The new elements, five in all, gave up to second-order approximations for both the magnetic field and the current density. Theoretical arguments showed these elements to be more economical for a given polynomial order of the approximated fields than the serendipity family of nodal elements. Further it was pointed out how the support of a source field computed by using edge elements could be made very small provided that a proper spanning tree was used in the edge element mesh. This was exploited for the voltage forcing technique, where source fields were used as basis functions, with unknown total currents in voltage forced conductors as degrees of freedom. The practical assessment of the edge elements proved the accuracy to improve with increasing polynomial order, both for local and global quantities. The most economical element was, however, one giving only complete first-order approximations for both fields. Further, the edge elements turned out to be better than the nodal elements also in practice. For the voltage forcing technique, source field basis functions which had small support, resulted in large reduction of the CPU-time for solving the main equation system, compared to source fields which had large support. The new elements can be used in a p-type adaptive scheme, and they should also be applicable for other tangentially continuous field problems. 67 refs., 34 figs., 10 tabs.
Sliding Adjustment for 3D Video Representation
Galpin Franck
2002-01-01
Full Text Available This paper deals with video coding of static scenes viewed by a moving camera. We propose an automatic way to encode such video sequences using several 3D models. Contrary to prior art in model-based coding where 3D models have to be known, the 3D models are automatically computed from the original video sequence. We show that several independent 3D models provide the same functionalities as one single 3D model, and avoid some drawbacks of the previous approaches. To achieve this goal we propose a novel algorithm of sliding adjustment, which ensures consistency of successive 3D models. The paper presents a method to automatically extract the set of 3D models and associate camera positions. The obtained representation can be used for reconstructing the original sequence, or virtual ones. It also enables 3D functionalities such as synthetic object insertion, lightning modification, or stereoscopic visualization. Results on real video sequences are presented.
3D laptop for defense applications
Edmondson, Richard; Chenault, David
2012-06-01
Polaris Sensor Technologies has developed numerous 3D display systems using a US Army patented approach. These displays have been developed as prototypes for handheld controllers for robotic systems and closed hatch driving, and as part of a TALON robot upgrade for 3D vision, providing depth perception for the operator for improved manipulation and hazard avoidance. In this paper we discuss the prototype rugged 3D laptop computer and its applications to defense missions. The prototype 3D laptop combines full temporal and spatial resolution display with the rugged Amrel laptop computer. The display is viewed through protective passive polarized eyewear, and allows combined 2D and 3D content. Uses include robot tele-operation with live 3D video or synthetically rendered scenery, mission planning and rehearsal, enhanced 3D data interpretation, and simulation.