A New Approach to Fully Automatic Mesh Generation
Institute of Scientific and Technical Information of China (English)
闵卫东; 张征明; 等
1995-01-01
Automatic mesh generation is one of the most important parts in CIMS (Computer Integrated Manufacturing System).A method based on mesh grading propagation which automatically produces a triangular mesh in a multiply connected planar region is presented in this paper.The method decomposes the planar region into convex subregions,using algorithms which run in linear time.For every subregion,an algorithm is used to generate shrinking polygons according to boundary gradings and form delaunay triangulation between two adjacent shrinking polygons,both in linear time.It automatically propagates boundary gradings into the interior of the region and produces satisfactory quasi-uniform mesh.
Procedure for the automatic mesh generation of innovative gear teeth
Directory of Open Access Journals (Sweden)
Radicella Andrea Chiaramonte
2016-01-01
Full Text Available After having described gear wheels with teeth having the two sides constituted by different involutes and their importance in engineering applications, we stress the need for an efficient procedure for the automatic mesh generation of innovative gear teeth. First, we describe the procedure for the subdivision of the tooth profile in the various possible cases, then we show the method for creating the subdivision mesh, defined by two series of curves called meridians and parallels. Finally, we describe how the above procedure for automatic mesh generation is able to solve specific cases that may arise when dealing with teeth having the two sides constituted by different involutes.
Automatic Mesh Generation on a Regular Background Grid
Institute of Scientific and Technical Information of China (English)
LO S.H; 刘剑飞
2002-01-01
This paper presents an automatic mesh generation procedure on a 2D domainbased on a regular background grid. The idea is to devise a robust mesh generation schemewith equal emphasis on quality and efficiency. Instead of using a traditional regular rectangulargrid, a mesh of equilateral triangles is employed to ensure triangular element of the best qualitywill be preserved in the interior of the domain.As for the boundary, it is to be generated by a node/segment insertion process. Nodes areinserted into the background mesh one by one following the sequence of the domain boundary.The local structure of the mesh is modified based on the Delaunay criterion with the introduc-tion of each node. Those boundary segments, which are not produced in the phase of nodeinsertion, will be recovered through a systematic element swap process. Two theorems will bepresented and proved to set up the theoretical basic of the boundary recovery part. Exampleswill be presented to demonstrate the robustness and the quality of the mesh generated by theproposed technique.
Shape design sensitivities using fully automatic 3-D mesh generation
Botkin, M. E.
1990-01-01
Previous work in three dimensional shape optimization involved specifying design variables by associating parameters directly with mesh points. More recent work has shown the use of fully-automatic mesh generation based upon a parameterized geometric representation. Design variables have been associated with a mathematical model of the part rather than the discretized representation. The mesh generation procedure uses a nonuniform grid intersection technique to place nodal points directly on the surface geometry. Although there exists an associativity between the mesh and the geometrical/topological entities, there is no mathematical functional relationship. This poses a problem during certain steps in the optimization process in which geometry modification is required. For the large geometrical changes which occur at the beginning of each optimization step, a completely new mesh is created. However, for gradient calculations many small changes must be made and it would be too costly to regenerate the mesh for each design variable perturbation. For that reason, a local remeshing procedure has been implemented which operates only on the specific edges and faces associated with the design variable being perturbed. Two realistic design problems are presented which show the efficiency of this process and test the accuracy of the gradient computations.
The mesh-matching algorithm: an automatic 3D mesh generator for Finite element structures
Couteau, B; Lavallee, S; Payan, Yohan; Lavallee, St\\'{e}phane
2000-01-01
Several authors have employed Finite Element Analysis (FEA) for stress and strain analysis in orthopaedic biomechanics. Unfortunately, the use of three-dimensional models is time consuming and consequently the number of analysis to be performed is limited. The authors have investigated a new method allowing automatically 3D mesh generation for structures as complex as bone for example. This method called Mesh-Matching (M-M) algorithm generated automatically customized 3D meshes of bones from an already existing model. The M-M algorithm has been used to generate FE models of ten proximal human femora from an initial one which had been experimentally validated. The new meshes seemed to demonstrate satisfying results.
Automatic generation of endocardial surface meshes with 1-to-1 correspondence from cine-MR images
Su, Yi; Teo, S.-K.; Lim, C. W.; Zhong, L.; Tan, R. S.
2015-03-01
In this work, we develop an automatic method to generate a set of 4D 1-to-1 corresponding surface meshes of the left ventricle (LV) endocardial surface which are motion registered over the whole cardiac cycle. These 4D meshes have 1- to-1 point correspondence over the entire set, and is suitable for advanced computational processing, such as shape analysis, motion analysis and finite element modelling. The inputs to the method are the set of 3D LV endocardial surface meshes of the different frames/phases of the cardiac cycle. Each of these meshes is reconstructed independently from border-delineated MR images and they have no correspondence in terms of number of vertices/points and mesh connectivity. To generate point correspondence, the first frame of the LV mesh model is used as a template to be matched to the shape of the meshes in the subsequent phases. There are two stages in the mesh correspondence process: (1) a coarse matching phase, and (2) a fine matching phase. In the coarse matching phase, an initial rough matching between the template and the target is achieved using a radial basis function (RBF) morphing process. The feature points on the template and target meshes are automatically identified using a 16-segment nomenclature of the LV. In the fine matching phase, a progressive mesh projection process is used to conform the rough estimate to fit the exact shape of the target. In addition, an optimization-based smoothing process is used to achieve superior mesh quality and continuous point motion.
Atlas-Based Automatic Generation of Subject-Specific Finite Element Tongue Meshes.
Bijar, Ahmad; Rohan, Pierre-Yves; Perrier, Pascal; Payan, Yohan
2016-01-01
Generation of subject-specific 3D finite element (FE) models requires the processing of numerous medical images in order to precisely extract geometrical information about subject-specific anatomy. This processing remains extremely challenging. To overcome this difficulty, we present an automatic atlas-based method that generates subject-specific FE meshes via a 3D registration guided by Magnetic Resonance images. The method extracts a 3D transformation by registering the atlas' volume image to the subject's one, and establishes a one-to-one correspondence between the two volumes. The 3D transformation field deforms the atlas' mesh to generate the subject-specific FE mesh. To preserve the quality of the subject-specific mesh, a diffeomorphic non-rigid registration based on B-spline free-form deformations is used, which guarantees a non-folding and one-to-one transformation. Two evaluations of the method are provided. First, a publicly available CT-database is used to assess the capability to accurately capture the complexity of each subject-specific Lung's geometry. Second, FE tongue meshes are generated for two healthy volunteers and two patients suffering from tongue cancer using MR images. It is shown that the method generates an appropriate representation of the subject-specific geometry while preserving the quality of the FE meshes for subsequent FE analysis. To demonstrate the importance of our method in a clinical context, a subject-specific mesh is used to simulate tongue's biomechanical response to the activation of an important tongue muscle, before and after cancer surgery. PMID:26577253
Applications of automatic mesh generation and adaptive methods in computational medicine
Energy Technology Data Exchange (ETDEWEB)
Schmidt, J.A.; Macleod, R.S. [Univ. of Utah, Salt Lake City, UT (United States); Johnson, C.R.; Eason, J.C. [Duke Univ., Durham, NC (United States)
1995-12-31
Important problems in Computational Medicine exist that can benefit from the implementation of adaptive mesh refinement techniques. Biological systems are so inherently complex that only efficient models running on state of the art hardware can begin to simulate reality. To tackle the complex geometries associated with medical applications we present a general purpose mesh generation scheme based upon the Delaunay tessellation algorithm and an iterative point generator. In addition, automatic, two- and three-dimensional adaptive mesh refinement methods are presented that are derived from local and global estimates of the finite element error. Mesh generation and adaptive refinement techniques are utilized to obtain accurate approximations of bioelectric fields within anatomically correct models of the heart and human thorax. Specifically, we explore the simulation of cardiac defibrillation and the general forward and inverse problems in electrocardiography (ECG). Comparisons between uniform and adaptive refinement techniques are made to highlight the computational efficiency and accuracy of adaptive methods in the solution of field problems in computational medicine.
Miyawaki, Shinjiro; Tawhai, Merryn H.; Hoffman, Eric A.; Lin, Ching-Long
2014-11-01
The authors have developed a method to automatically generate non-uniform CFD mesh for image-based human airway models. The sizes of generated tetrahedral elements vary in both radial and longitudinal directions to account for boundary layer and multiscale nature of pulmonary airflow. The proposed method takes advantage of our previously developed centerline-based geometry reconstruction method. In order to generate the mesh branch by branch in parallel, we used the open-source programs Gmsh and TetGen for surface and volume meshes, respectively. Both programs can specify element sizes by means of background mesh. The size of an arbitrary element in the domain is a function of wall distance, element size on the wall, and element size at the center of airway lumen. The element sizes on the wall are computed based on local flow rate and airway diameter. The total number of elements in the non-uniform mesh (10 M) was about half of that in the uniform mesh, although the computational time for the non-uniform mesh was about twice longer (170 min). The proposed method generates CFD meshes with fine elements near the wall and smooth variation of element size in longitudinal direction, which are required, e.g., for simulations with high flow rate. NIH Grants R01-HL094315, U01-HL114494, and S10-RR022421. Computer time provided by XSEDE.
International Nuclear Information System (INIS)
An expert system for generating an effective mesh distribution for the SN particle transport simulation has been developed. This expert system consists of two main parts: 1) an algorithm for generating an effective mesh distribution in a serial environment, and 2) an algorithm for inference of an effective domain decomposition strategy for parallel computing. For the first part, the algorithm prepares an effective mesh distribution considering problem physics and the spatial differencing scheme. For the second part, the algorithm determines a parallel-performance-index (PPI), which is defined as the ratio of the granularity to the degree-of-coupling. The parallel-performance-index provides expected performance of an algorithm depending on computing environment and resources. A large index indicates a high granularity algorithm with relatively low coupling among processors. This expert system has been successfully tested within the PENTRAN (Parallel Environment Neutral-Particle Transport) code system for simulating real-life shielding problems. (authors)
Spherical geodesic mesh generation
Energy Technology Data Exchange (ETDEWEB)
Fung, Jimmy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kenamond, Mark Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Burton, Donald E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shashkov, Mikhail Jurievich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-02-27
In ALE simulations with moving meshes, mesh topology has a direct influence on feature representation and code robustness. In three-dimensional simulations, modeling spherical volumes and features is particularly challenging for a hydrodynamics code. Calculations on traditional spherical meshes (such as spin meshes) often lead to errors and symmetry breaking. Although the underlying differencing scheme may be modified to rectify this, the differencing scheme may not be accessible. This work documents the use of spherical geodesic meshes to mitigate solution-mesh coupling. These meshes are generated notionally by connecting geodesic surface meshes to produce triangular-prismatic volume meshes. This mesh topology is fundamentally different from traditional mesh topologies and displays superior qualities such as topological symmetry. This work describes the geodesic mesh topology as well as motivating demonstrations with the FLAG hydrocode.
Energy Technology Data Exchange (ETDEWEB)
Motta, R.S.; Afonso, S.M.B.; Willmersdorf, R.B.; Lyra, P.R.M. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Cabral, H.L.D. [TRANSPETRO, Rio de Janeiro, RJ (Brazil); Andrade, E.Q. [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)
2009-07-01
Although the Finite Element Method (FEM) has proved to be a powerful tool to predict the failure pressure of corroded pipes, the generation of good computational models of pipes with corrosion defects can take several days. This makes the use of computational simulation procedure difficult to apply in practice. The main purpose of this work is to develop a set of computational tools to produce automatically models of pipes with defects, ready to be analyzed with commercial FEM programs, starting from a few parameters that locate and provide the main dimensions of the defect or a series of defects. Here these defects can be internal and external and also assume general spatial locations along the pipe. Idealized rectangular and elliptic geometries can be generated. These tools were based on MSC.PATRAN pre and post-processing programs and were written with PCL (Patran Command Language). The program for the automatic generation of models (PIPEFLAW) has a simplified and customized graphical interface, so that an engineer with basic notions of computational simulation with the FEM can generate rapidly models that result in precise and reliable simulations. Some examples of models of pipes with defects generated by the PIPEFLAW system are shown, and the results of numerical analyses, done with the tools presented in this work, are compared with, empiric results. (author)
Directory of Open Access Journals (Sweden)
Milašinović Danko Z.
2008-01-01
Full Text Available Cardiovascular diseases are common and a special difficulty in their curing is diagnostics. Modern medical instruments can provide data that is much more adequate for computer modeling. Computer simulations of blood flow through the cardiovascular organs give powerful advantages to scientists today. The motivation for this work is raw data that our Center recently received from the University Clinical center in Heidelberg from a multislice CT scanner. In this work raw data from CT scanner was used for creating a 3D model of the aorta. In this process we used Gmsh, TetGen (Hang Si as well as our own software tools, and the result was the 8-node (brick mesh on which the calculation was run. The results obtained were very satisfactory so...
Scandalously Parallelizable Mesh Generation
Bortz, David
2011-01-01
We propose a novel approach which employs random sampling to generate an accurate non-uniform mesh for numerically solving Partial Differential Equation Boundary Value Problems (PDE-BVP's). From a uniform probability distribution U over a 1D domain, we sample M discretizations of size N where M>>N. The statistical moments of the solutions to a given BVP on each of the M ultra-sparse meshes provide insight into identifying highly accurate non-uniform meshes. Essentially, we use the pointwise mean and variance of the coarse-grid solutions to construct a mapping Q(x) from uniformly to non-uniformly spaced mesh-points. The error convergence properties of the approximate solution to the PDE-BVP on the non-uniform mesh are superior to a uniform mesh for a certain class of BVP's. In particular, the method works well for BVP's with locally non-smooth solutions. We present a framework for studying the sampled sparse-mesh solutions and provide numerical evidence for the utility of this approach as applied to a set of e...
Patchimpattapong, Apisit
This dissertation develops an expert system for generating an effective spatial mesh distribution for the discrete ordinates particle transport method in a parallel environment. This expert system consists of two main parts: (1) an algorithm for generating an effective mesh distribution in a serial environment, and (2) an algorithm for inference of an effective domain decomposition strategy for parallel computing. The mesh generation algorithm consists of four steps: creation of a geometric model as partitioned into coarse meshes, determination of an approximate flux shape, selection of appropriate differencing schemes, and generation of an effective fine mesh distribution. A geometric model was created using AutoCAD. A parallel code PENFC (Parallel Environment Neutral-Particle First Collision) has been developed to calculate an uncollided flux in a 3-D Cartesian geometry. The appropriate differencing schemes were selected based on the uncollided flux distribution using a least squares methodology. A menu-driven serial code PENXMSH has been developed to generate an effective spatial mesh distribution that preserves problem geometry and physics. The domain decomposition selection process involves evaluation of the four factors that affect parallel performance, which include number of processors and memory available per processor, load balance, granularity, and degree-of-coupling among processors. These factors are used to derive a parallel-performance-index that provides expected performance of a parallel algorithm depending on computing environment and resources. A large index indicates a high granularity algorithm with relatively low coupling among processors. This expert system has been successfully tested within the PENTRAN (Parallel Environment Neutral-Particle Transport) code system for simulating real-life shielding problems: the VENUS-3 experimental facility and the BWR core shroud.
Miyawaki, Shinjiro; Tawhai, Merryn H.; Hoffman, Eric A.; Lin, Ching-Long
2013-11-01
The authors propose a method to automatically generate three-dimensional subject-specific airway geometries and meshes for computational fluid dynamics (CFD) studies of aerosol delivery in the human lungs. The proposed method automatically expands computed tomography (CT)-based airway skeleton to generate the centerline (CL)-based model, and then fits it to the CT-segmented geometry to generate the hybrid CL-CT-based model. To produce a turbulent laryngeal jet known to affect aerosol transport, we developed a physiologically-consistent laryngeal model that can be attached to the trachea of the above models. We used Gmsh to automatically generate the mesh for the above models. To assess the quality of the models, we compared the regional aerosol distributions in a human lung predicted by the hybrid model and the manually generated CT-based model. The aerosol distribution predicted by the hybrid model was consistent with the prediction by the CT-based model. We applied the hybrid model to 8 healthy and 16 severe asthmatic subjects, and average geometric error was 3.8% of the branch radius. The proposed method can be potentially applied to the branch-by-branch analyses of a large population of healthy and diseased lungs. NIH Grants R01-HL-094315 and S10-RR-022421, CT data provided by SARP, and computer time provided by XSEDE.
Automated quadrilateral mesh generation for digital image structures
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
With the development of advanced imaging technology, digital images are widely used. This paper proposes an automatic quadrilateral mesh generation algorithm for multi-colour imaged structures. It takes an original arbitrary digital image as an input for automatic quadrilateral mesh generation, this includes removing the noise, extracting and smoothing the boundary geometries between different colours, and automatic all-quad mesh generation with the above boundaries as constraints. An application example is...
Problem-adapted mesh generation with FEM-features
Werner, Horst; Weber, Christian; Schilke, Martin
2000-01-01
Today automatic meshing of CAD geometry is the most common method of FEM mesh generation. However, to get results of acceptable accuracy with universal meshing algorithms it is necessary to use rather small-sized elements which leads to high memory and CPU time consumption. Furthermore, the irregularity of automatically generatated meshes makes it difficult to create well-defined local areas with different material properties. A solution for this problem is the application of predefined build...
Cardiovascular and lung mesh generation based on centerlines.
Marchandise, E; Geuzaine, C; Remacle, J F
2013-06-01
We present a fully automatic procedure for the mesh generation of tubular geometries such as blood vessels or airways. The procedure is implemented in the open-source Gmsh software and relies on a centerline description of the input geometry. The presented method can generate different type of meshes: isotropic tetrahedral meshes, anisotropic tetrahedral meshes, and mixed hexahedral/tetrahedral meshes. Additionally, a multiple layered arterial wall can be generated with a variable thickness. All the generated meshes rely on a mesh size field and a mesh metric that is based on centerline descriptions, namely the distance to the centerlines and a local reference system based on the tangent and the normal directions to the centerlines. Different examples show that the proposed method is very efficient and robust and leads to high quality computational meshes. PMID:23606344
Nanowire mesh solar fuels generator
Energy Technology Data Exchange (ETDEWEB)
Yang, Peidong; Chan, Candace; Sun, Jianwei; Liu, Bin
2016-05-24
This disclosure provides systems, methods, and apparatus related to a nanowire mesh solar fuels generator. In one aspect, a nanowire mesh solar fuels generator includes (1) a photoanode configured to perform water oxidation and (2) a photocathode configured to perform water reduction. The photocathode is in electrical contact with the photoanode. The photoanode may include a high surface area network of photoanode nanowires. The photocathode may include a high surface area network of photocathode nanowires. In some embodiments, the nanowire mesh solar fuels generator may include an ion conductive polymer infiltrating the photoanode and the photocathode in the region where the photocathode is in electrical contact with the photoanode.
GENERATION OF IRREGULAR HEXAGONAL MESHES
Directory of Open Access Journals (Sweden)
Vlasov Aleksandr Nikolaevich
2012-07-01
Decomposition is performed in a constructive way and, as option, it involves meshless representation. Further, this mapping method is used to generate the calculation mesh. In this paper, the authors analyze different cases of mapping onto simply connected and bi-connected canonical domains. They represent forward and backward mapping techniques. Their potential application for generation of nonuniform meshes within the framework of the asymptotic homogenization theory is also performed to assess and project effective characteristics of heterogeneous materials (composites.
Documentation for MeshKit - Reactor Geometry (&mesh) Generator
Energy Technology Data Exchange (ETDEWEB)
Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-09-30
This report gives documentation for using MeshKit’s Reactor Geometry (and mesh) Generator (RGG) GUI and also briefly documents other algorithms and tools available in MeshKit. RGG is a program designed to aid in modeling and meshing of complex/large hexagonal and rectilinear reactor cores. RGG uses Argonne’s SIGMA interfaces, Qt and VTK to produce an intuitive user interface. By integrating a 3D view of the reactor with the meshing tools and combining them into one user interface, RGG streamlines the task of preparing a simulation mesh and enables real-time feedback that reduces accidental scripting mistakes that could waste hours of meshing. RGG interfaces with MeshKit tools to consolidate the meshing process, meaning that going from model to mesh is as easy as a button click. This report is designed to explain RGG v 2.0 interface and provide users with the knowledge and skills to pilot RGG successfully. Brief documentation of MeshKit source code, tools and other algorithms available are also presented for developers to extend and add new algorithms to MeshKit. RGG tools work in serial and parallel and have been used to model complex reactor core models consisting of conical pins, load pads, several thousands of axially varying material properties of instrumentation pins and other interstices meshes.
Energy Technology Data Exchange (ETDEWEB)
Pescarini, M.; Orsi, R.; Martinelli, T. [ENEA, Ente per le Nuove Tecnologie, l' Energia e l' Ambiente, Centro Ricerche Ezio Clementel Bologna (Italy)
2003-07-01
In many practical radiation transport applications today the cost for solving refined, large size and complex multi-dimensional problems is not so much computing but is linked to the cumbersome effort required by an expert to prepare a detailed geometrical model, verify and validate that it is correct and represents, to a specified tolerance, the real design or facility. This situation is, in particular, relevant and frequent in reactor core criticality and shielding calculations, with three-dimensional (3D) general purpose radiation transport codes, requiring a very large number of meshes and high performance computers. The need for developing tools that make easier the task to the physicist or engineer, by reducing the time required, by facilitating through effective graphical display the verification of correctness and, finally, that help the interpretation of the results obtained, has clearly emerged. The paper shows the results of efforts in this field through detailed simulations of a complex shielding benchmark experiment. In the context of the activities proposed by the OECD/NEA Nuclear Science Committee (NSC) Task Force on Computing Radiation Dose and Modelling of Radiation-Induced Degradation of Reactor Components (TFRDD), the ENEA-Bologna Nuclear Data Centre contributed with an analysis of the VENUS-3 low-flux neutron shielding benchmark experiment (SCK/CEN-Mol, Belgium). One of the targets of the work was to test the BOT3P system, originally developed at the Nuclear Data Centre in ENEA-Bologna and actually released to OECD/NEA Data Bank for free distribution. BOT3P, ancillary system of the DORT (2D) and TORT (3D) SN codes, permits a flexible automatic generation of spatial mesh grids in Cartesian or cylindrical geometry, through combinatorial geometry algorithms, following a simplified user-friendly approach. This system demonstrated its validity also in core criticality analyses, as for example the Lewis MOX fuel benchmark, permitting to easily
International Nuclear Information System (INIS)
In many practical radiation transport applications today the cost for solving refined, large size and complex multi-dimensional problems is not so much computing but is linked to the cumbersome effort required by an expert to prepare a detailed geometrical model, verify and validate that it is correct and represents, to a specified tolerance, the real design or facility. This situation is, in particular, relevant and frequent in reactor core criticality and shielding calculations, with three-dimensional (3D) general purpose radiation transport codes, requiring a very large number of meshes and high performance computers. The need for developing tools that make easier the task to the physicist or engineer, by reducing the time required, by facilitating through effective graphical display the verification of correctness and, finally, that help the interpretation of the results obtained, has clearly emerged. The paper shows the results of efforts in this field through detailed simulations of a complex shielding benchmark experiment. In the context of the activities proposed by the OECD/NEA Nuclear Science Committee (NSC) Task Force on Computing Radiation Dose and Modelling of Radiation-Induced Degradation of Reactor Components (TFRDD), the ENEA-Bologna Nuclear Data Centre contributed with an analysis of the VENUS-3 low-flux neutron shielding benchmark experiment (SCK/CEN-Mol, Belgium). One of the targets of the work was to test the BOT3P system, originally developed at the Nuclear Data Centre in ENEA-Bologna and actually released to OECD/NEA Data Bank for free distribution. BOT3P, ancillary system of the DORT (2D) and TORT (3D) SN codes, permits a flexible automatic generation of spatial mesh grids in Cartesian or cylindrical geometry, through combinatorial geometry algorithms, following a simplified user-friendly approach. This system demonstrated its validity also in core criticality analyses, as for example the Lewis MOX fuel benchmark, permitting to easily
Gaussian curvature analysis allows for automatic block placement in multi-block hexahedral meshing.
Ramme, Austin J; Shivanna, Kiran H; Magnotta, Vincent A; Grosland, Nicole M
2011-10-01
Musculoskeletal finite element analysis (FEA) has been essential to research in orthopaedic biomechanics. The generation of a volumetric mesh is often the most challenging step in a FEA. Hexahedral meshing tools that are based on a multi-block approach rely on the manual placement of building blocks for their mesh generation scheme. We hypothesise that Gaussian curvature analysis could be used to automatically develop a building block structure for multi-block hexahedral mesh generation. The Automated Building Block Algorithm incorporates principles from differential geometry, combinatorics, statistical analysis and computer science to automatically generate a building block structure to represent a given surface without prior information. We have applied this algorithm to 29 bones of varying geometries and successfully generated a usable mesh in all cases. This work represents a significant advancement in automating the definition of building blocks. PMID:20924860
Volume Decomposition and Feature Recognition for Hexahedral Mesh Generation
International Nuclear Information System (INIS)
Considerable progress has been made on automatic hexahedral mesh generation in recent years. Several automatic meshing algorithms have proven to be very reliable on certain classes of geometry. While it is always worth pursuing general algorithms viable on more general geometry, a combination of the well-established algorithms is ready to take on classes of complicated geometry. By partitioning the entire geometry into meshable pieces matched with appropriate meshing algorithm the original geometry becomes meshable and may achieve better mesh quality. Each meshable portion is recognized as a meshing feature. This paper, which is a part of the feature based meshing methodology, presents the work on shape recognition and volume decomposition to automatically decompose a CAD model into meshable volumes. There are four phases in this approach: (1) Feature Determination to extinct decomposition features, (2) Cutting Surfaces Generation to form the ''tailored'' cutting surfaces, (3) Body Decomposition to get the imprinted volumes; and (4) Meshing Algorithm Assignment to match volumes decomposed with appropriate meshing algorithms. The feature determination procedure is based on the CLoop feature recognition algorithm that is extended to be more general. Results are demonstrated over several parts with complicated topology and geometry
SHARP/PRONGHORN Interoperability: Mesh Generation
Energy Technology Data Exchange (ETDEWEB)
Avery Bingham; Javier Ortensi
2012-09-01
Progress toward collaboration between the SHARP and MOOSE computational frameworks has been demonstrated through sharing of mesh generation and ensuring mesh compatibility of both tools with MeshKit. MeshKit was used to build a three-dimensional, full-core very high temperature reactor (VHTR) reactor geometry with 120-degree symmetry, which was used to solve a neutron diffusion critical eigenvalue problem in PRONGHORN. PRONGHORN is an application of MOOSE that is capable of solving coupled neutron diffusion, heat conduction, and homogenized flow problems. The results were compared to a solution found on a 120-degree, reflected, three-dimensional VHTR mesh geometry generated by PRONGHORN. The ability to exchange compatible mesh geometries between the two codes is instrumental for future collaboration and interoperability. The results were found to be in good agreement between the two meshes, thus demonstrating the compatibility of the SHARP and MOOSE frameworks. This outcome makes future collaboration possible.
Automatic Dance Lesson Generation
Yang, Yang; Leung, H.; Yue, Lihua; Deng, LiQun
2012-01-01
In this paper, an automatic lesson generation system is presented which is suitable in a learning-by-mimicking scenario where the learning objects can be represented as multiattribute time series data. The dance is used as an example in this paper to illustrate the idea. Given a dance motion sequence as the input, the proposed lesson generation…
Dancette, S.; Browet, A.; Martin, G.; Willemet, M.; Delannay, L.
2016-06-01
A new procedure for microstructure-based finite element modeling of polycrystalline aggregates is presented. The proposed method relies (i) on an efficient graph-based community detection algorithm for crystallographic data segmentation and feature contour extraction and (ii) on the generation of selectively refined meshes conforming to grain boundaries. It constitutes a versatile and close to automatic environment for meshing complex microstructures. The procedure is illustrated with polycrystal microstructures characterized by orientation imaging microscopy. Hot deformation of a Duplex stainless steel is investigated based on ex-situ EBSD measurements performed on the same region of interest before and after deformation. A finite element mesh representing the initial microstructure is generated and then used in a crystal plasticity simulation of the plane strain compression. Simulation results and experiments are in relatively good agreement, confirming a large potential for such directly coupled experimental and modeling analyses, which is facilitated by the present image-based meshing procedure.
Adaptive mesh generation for image registration and segmentation
DEFF Research Database (Denmark)
Fogtmann, Mads; Larsen, Rasmus
This paper deals with the problem of generating quality tetrahedral meshes for image registration. From an initial coarse mesh the approach matches the mesh to the image volume by combining red-green subdivision and mesh evolution through mesh-to-image matching regularized with a mesh quality...
Three-dimensional modeling and highly refined mesh generation of the aorta artery and its tunics
International Nuclear Information System (INIS)
This paper describes strategies and techniques to perform modeling and automatic mesh generation of the aorta artery and its tunics (adventitia, media and intima walls), using open source codes. The models were constructed in the Blender package and Python scripts were used to export the data necessary for the mesh generation in TetGen. The strategies proposed are able to provide meshes of complicated and irregular volumes, with a large number of mesh elements involved (12,000,000 tetrahedrons approximately). These meshes can be used to perform computational simulations by Finite Element Method (FEM).
Mesh Generation and Adaption for High Reynolds Number RANS Computations Project
National Aeronautics and Space Administration — This proposal offers to provide NASA with an automatic mesh generator for the simulation of aerodynamic flows using Reynolds-Averages Navier-Stokes (RANS) models....
Mesh Generation and Adaption for High Reynolds Number RANS Computations Project
National Aeronautics and Space Administration — The innovation of our Phase II STTR program is to develop and provide to NASA automatic mesh generation software for the simulation of fluid flows using...
Generating quality tetrahedral meshes from binary volumes
DEFF Research Database (Denmark)
Hansen, Mads Fogtmann; Bærentzen, Jakob Andreas; Larsen, Rasmus
2010-01-01
use these measures to generate high quality meshes from signed distance maps. This paper also describes an approach for computing (smooth) signed distance maps from binary volumes as volumetric data in many cases originate from segmentation of objects from imaging techniques such as CT, MRI, etc. The...
Automatic Tooth Segmentation of Dental Mesh Based on Harmonic Fields.
Liao, Sheng-hui; Liu, Shi-jian; Zou, Bei-ji; Ding, Xi; Liang, Ye; Huang, Jun-hui
2015-01-01
An important preprocess in computer-aided orthodontics is to segment teeth from the dental models accurately, which should involve manual interactions as few as possible. But fully automatic partition of all teeth is not a trivial task, since teeth occur in different shapes and their arrangements vary substantially from one individual to another. The difficulty is exacerbated when severe teeth malocclusion and crowding problems occur, which is a common occurrence in clinical cases. Most published methods in this area either are inaccurate or require lots of manual interactions. Motivated by the state-of-the-art general mesh segmentation methods that adopted the theory of harmonic field to detect partition boundaries, this paper proposes a novel, dental-targeted segmentation framework for dental meshes. With a specially designed weighting scheme and a strategy of a priori knowledge to guide the assignment of harmonic constraints, this method can identify teeth partition boundaries effectively. Extensive experiments and quantitative analysis demonstrate that the proposed method is able to partition high-quality teeth automatically with robustness and efficiency. PMID:26413507
Automatic Tooth Segmentation of Dental Mesh Based on Harmonic Fields
Directory of Open Access Journals (Sweden)
Sheng-hui Liao
2015-01-01
Full Text Available An important preprocess in computer-aided orthodontics is to segment teeth from the dental models accurately, which should involve manual interactions as few as possible. But fully automatic partition of all teeth is not a trivial task, since teeth occur in different shapes and their arrangements vary substantially from one individual to another. The difficulty is exacerbated when severe teeth malocclusion and crowding problems occur, which is a common occurrence in clinical cases. Most published methods in this area either are inaccurate or require lots of manual interactions. Motivated by the state-of-the-art general mesh segmentation methods that adopted the theory of harmonic field to detect partition boundaries, this paper proposes a novel, dental-targeted segmentation framework for dental meshes. With a specially designed weighting scheme and a strategy of a priori knowledge to guide the assignment of harmonic constraints, this method can identify teeth partition boundaries effectively. Extensive experiments and quantitative analysis demonstrate that the proposed method is able to partition high-quality teeth automatically with robustness and efficiency.
Constrained CVT Meshes and a Comparison of Triangular Mesh Generators
Energy Technology Data Exchange (ETDEWEB)
Nguyen, Hoa [Florida State University; Burkardt, John [Florida State University; Gunzburger, Max [Florida State University; Ju, Lili [University of South Carolina; Saka, Yuki [Florida State University
2009-01-01
Mesh generation in regions in Euclidean space is a central task in computational science, and especially for commonly used numerical methods for the solution of partial differential equations, e.g., finite element and finite volume methods. We focus on the uniform Delaunay triangulation of planar regions and, in particular, on how one selects the positions of the vertices of the triangulation. We discuss a recently developed method, based on the centroidal Voronoi tessellation (CVT) concept, for effecting such triangulations and present two algorithms, including one new one, for CVT-based grid generation. We also compare several methods, including CVT-based methods, for triangulating planar domains. To this end, we define several quantitative measures of the quality of uniform grids. We then generate triangulations of several planar regions, including some having complexities that are representative of what one may encounter in practice. We subject the resulting grids to visual and quantitative comparisons and conclude that all the methods considered produce high-quality uniform grids and that the CVT-based grids are at least as good as any of the others.
Stochastic domain decomposition for time dependent adaptive mesh generation
Bihlo, Alexander; Walsh, Emily J
2015-01-01
The efficient generation of meshes is an important component in the numerical solution of problems in physics and engineering. Of interest are situations where global mesh quality and a tight coupling to the solution of the physical partial differential equation (PDE) is important. We consider parabolic PDE mesh generation and present a method for the construction of adaptive meshes in two spatial dimensions using stochastic domain decomposition that is suitable for an implementation in a multi- or many-core environment. Methods for mesh generation on periodic domains are also provided. The mesh generator is coupled to a time dependent physical PDE and the system is evolved using an alternating solution procedure. The method uses the stochastic representation of the exact solution of a parabolic linear mesh generator to find the location of an adaptive mesh along the (artificial) subdomain interfaces. The deterministic evaluation of the mesh over each subdomain can then be obtained completely independently us...
An Adaptive Mesh Algorithm: Mesh Structure and Generation
Energy Technology Data Exchange (ETDEWEB)
Scannapieco, Anthony J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-06-21
The purpose of Adaptive Mesh Refinement is to minimize spatial errors over the computational space not to minimize the number of computational elements. The additional result of the technique is that it may reduce the number of computational elements needed to retain a given level of spatial accuracy. Adaptive mesh refinement is a computational technique used to dynamically select, over a region of space, a set of computational elements designed to minimize spatial error in the computational model of a physical process. The fundamental idea is to increase the mesh resolution in regions where the physical variables are represented by a broad spectrum of modes in k-space, hence increasing the effective global spectral coverage of those physical variables. In addition, the selection of the spatially distributed elements is done dynamically by cyclically adjusting the mesh to follow the spectral evolution of the system. Over the years three types of AMR schemes have evolved; block, patch and locally refined AMR. In block and patch AMR logical blocks of various grid sizes are overlaid to span the physical space of interest, whereas in locally refined AMR no logical blocks are employed but locally nested mesh levels are used to span the physical space. The distinction between block and patch AMR is that in block AMR the original blocks refine and coarsen entirely in time, whereas in patch AMR the patches change location and zone size with time.
CUBIT mesh generation environment. Volume 1: Users manual
Energy Technology Data Exchange (ETDEWEB)
Blacker, T.D.; Bohnhoff, W.J.; Edwards, T.L. [and others
1994-05-01
The CUBIT mesh generation environment is a two- and three-dimensional finite element mesh generation tool which is being developed to pursue the goal of robust and unattended mesh generation--effectively automating the generation of quadrilateral and hexahedral elements. It is a solid-modeler based preprocessor that meshes volume and surface solid models for finite element analysis. A combination of techniques including paving, mapping, sweeping, and various other algorithms being developed are available for discretizing the geometry into a finite element mesh. CUBIT also features boundary layer meshing specifically designed for fluid flow problems. Boundary conditions can be applied to the mesh through the geometry and appropriate files for analysis generated. CUBIT is specifically designed to reduce the time required to create all-quadrilateral and all-hexahedral meshes. This manual is designed to serve as a reference and guide to creating finite element models in the CUBIT environment.
Polygonal Prism Mesh in the Viscous Layers for the Polyhedral Mesh Generator, PolyGen
International Nuclear Information System (INIS)
Polyhedral mesh has been known to have some benefits over the tetrahedral mesh. Efforts have been made to set up a polyhedral mesh generation system with open source programs SALOME and TetGen. The evaluation has shown that the polyhedral mesh generation system is promising. But it is necessary to extend the capability of the system to handle the viscous layers to be a generalized mesh generator. A brief review to the previous works on the mesh generation for the viscous layers will be made in section 2. Several challenging issues for the polygonal prism mesh generation will be discussed as well. The procedure to generate a polygonal prism mesh will be discussed in detail in section 3. Conclusion will be followed in section 4. A procedure to generate meshes in the viscous layers with PolyGen has been successfully designed. But more efforts have to be exercised to find the best way for the generating meshes for viscous layers. Using the extrusion direction of the STL data will the first of the trials in the near future
Update on Development of Mesh Generation Algorithms in MeshKit
Energy Technology Data Exchange (ETDEWEB)
Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Vanderzee, Evan [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-09-30
MeshKit uses a graph-based design for coding all its meshing algorithms, which includes the Reactor Geometry (and mesh) Generation (RGG) algorithms. This report highlights the developmental updates of all the algorithms, results and future work. Parallel versions of algorithms, documentation and performance results are reported. RGG GUI design was updated to incorporate new features requested by the users; boundary layer generation and parallel RGG support were added to the GUI. Key contributions to the release, upgrade and maintenance of other SIGMA1 libraries (CGM and MOAB) were made. Several fundamental meshing algorithms for creating a robust parallel meshing pipeline in MeshKit are under development. Results and current status of automated, open-source and high quality nuclear reactor assembly mesh generation algorithms such as trimesher, quadmesher, interval matching and multi-sweeper are reported.
Automatic generation of documents
Rosa Gini; Jacopo Pasquini
2006-01-01
This paper describes a natural interaction between Stata and markup languages. Stata’s programming and analysis features, together with the flexibility in output formatting of markup languages, allow generation and/or update of whole documents (reports, presentations on screen or web, etc.). Examples are given for both LaTeX and HTML. Stata’s commands are mainly dedicated to analysis of data on a computer screen and output of analysis stored in a log file available to researchers for later re...
Automatic Generation of Technical Documentation
Reiter, Ehud; Mellish, Chris; Levine, John
1994-01-01
Natural-language generation (NLG) techniques can be used to automatically produce technical documentation from a domain knowledge base and linguistic and contextual models. We discuss this application of NLG technology from both a technical and a usefulness (costs and benefits) perspective. This discussion is based largely on our experiences with the IDAS documentation-generation project, and the reactions various interested people from industry have had to IDAS. We hope that this summary of ...
Image-Based Geometric Modeling and Mesh Generation
2013-01-01
As a new interdisciplinary research area, “image-based geometric modeling and mesh generation” integrates image processing, geometric modeling and mesh generation with finite element method (FEM) to solve problems in computational biomedicine, materials sciences and engineering. It is well known that FEM is currently well-developed and efficient, but mesh generation for complex geometries (e.g., the human body) still takes about 80% of the total analysis time and is the major obstacle to reduce the total computation time. It is mainly because none of the traditional approaches is sufficient to effectively construct finite element meshes for arbitrarily complicated domains, and generally a great deal of manual interaction is involved in mesh generation. This contributed volume, the first for such an interdisciplinary topic, collects the latest research by experts in this area. These papers cover a broad range of topics, including medical imaging, image alignment and segmentation, image-to-mesh conversion,...
Automatic Generation of Technical Documentation
Reiter, E R; Levine, J; Reiter, Ehud; Mellish, Chris; Levine, John
1994-01-01
Natural-language generation (NLG) techniques can be used to automatically produce technical documentation from a domain knowledge base and linguistic and contextual models. We discuss this application of NLG technology from both a technical and a usefulness (costs and benefits) perspective. This discussion is based largely on our experiences with the IDAS documentation-generation project, and the reactions various interested people from industry have had to IDAS. We hope that this summary of our experiences with IDAS and the lessons we have learned from it will be beneficial for other researchers who wish to build technical-documentation generation systems.
STL Triangular Mesh Generation Based on SAT Model
Directory of Open Access Journals (Sweden)
Yuwei Zhang
2013-06-01
Full Text Available Mesh generation is a fundamental technique in multiple domains. In this study, a STL triangular mesh generation method based on SAT model is proposed. Two novel triangulation methods, the constrained Delaunay algorithm and the grid subtraction algorithm, are employed on the multi-loop planer regions and the curved surfaces respectively. For the use of node adjustment, the mesh nodes on the surface boundary are strictly matched, with no cracks created on the joint of model surfaces. Experiments show that the proposed solution works effectively and high quality of the mesh model is achieved.
Energy Technology Data Exchange (ETDEWEB)
Balaven-Clermidy, S.
2001-12-01
Oil reservoir simulations study multiphase flows in porous media. These flows are described and evaluated through numerical schemes on a discretization of the reservoir domain. In this thesis, we were interested in this spatial discretization and a new kind of hybrid mesh has been proposed where the radial nature of flows in the vicinity of wells is directly taken into account in the geometry. Our modular approach described wells and their drainage area through radial circular meshes. These well meshes are inserted in a structured reservoir mesh (a Corner Point Geometry mesh) made up with hexahedral cells. Finally, in order to generate a global conforming mesh, proper connections are realized between the different kinds of meshes through unstructured transition ones. To compute these transition meshes that we want acceptable in terms of finite volume methods, an automatic method based on power diagrams has been developed. Our approach can deal with a homogeneous anisotropic medium and allows the user to insert vertical or horizontal wells as well as secondary faults in the reservoir mesh. Our work has been implemented, tested and validated in 2D and 2D1/2. It can also be extended in 3D when the geometrical constraints are simplicial ones: points, segments and triangles. (author)
METHOD FOR ADAPTIVE MESH GENERATION BASED ON GEOMETRICAL FEATURES OF 3D SOLID
Institute of Scientific and Technical Information of China (English)
HUANG Xiaodong; DU Qungui; YE Bangyan
2006-01-01
In order to provide a guidance to specify the element size dynamically during adaptive finite element mesh generation, adaptive criteria are firstly defined according to the relationships between the geometrical features and the elements of 3D solid. Various modes based on different datum geometrical elements, such as vertex, curve, surface, and so on, are then designed for generating local refmed mesh. With the guidance of the defined criteria, different modes are automatically selected to apply on the appropriate datum objects to program the element size in the local special areas. As a result, the control information of element size is successfully programmed coveting the entire domain based on the geometrical features of 3D solid. A new algorithm based on Delaunay triangulation is then developed for generating 3D adaptive fmite element mesh, in which the element size is dynamically specified to catch the geometrical features and suitable tetrahedron facets are selected to locate interior nodes continuously. As a result, adaptive mesh with good-quality elements is generated. Examples show that the proposed method can be successfully applied to adaptive finite element mesh automatic generation based on the geometrical features of 3D solid.
Towards Unstructured Mesh Generation Using the Inverse Poisson Problem
Bunin, Guy
2008-01-01
A novel approach to unstructured quadrilateral mesh generation for planar domains is presented. Away from irregular vertices, the resulting meshes have the properties of nearly conformal grids. The technique is based on a theoretical relation between the present problem, and the inverse Poisson (IP) problem with point sources. An IP algorithm is described, which constructs a point-source distribution, whose sources correspond to the irregular vertices of the mesh. Both the background theory a...
Hex-dominant mesh generation for basin modeling with complex geometry
International Nuclear Information System (INIS)
Basin modeling aims to reconstruct the geological history of a basin and its oil system by means of fluid flow simulations, which is done by using a series of meshes describing basin geometry at each geological instant. These meshes are preferably hexahedral rather than tetrahedral in virtue for better numerical results. The basin can simply consist of geological layers delimited one from another by horizons. It can be geometrically complex with one or more faults interrupting the layers, which is barely studied but increasingly demanded. This paper exposes an automatic method which generates hex-dominant meshes for basin modeling with complex geometry. Firstly, based on their triangulations at the latest instant, 3D surface grids are generated with identical topology for all the horizons, and with some quadrilaterals being split across the diagonals to adapt to fault traces. Afterwards, all instants are iterated to generate corresponding meshes by firstly applying horizon and fault displacement on the mesh generated for precedent instant; the method then connects the bottom and top surface grids of the new layer along corresponding nodes, and splits certain cells along faults when necessary. Simulations have been carried out on generated meshes with satisfactory results.
Robust Generation of Signed Distance Fields from Triangle Meshes
DEFF Research Database (Denmark)
Bærentzen, Jakob Andreas
A new method for robust generation of distance fields from triangle meshes is presented. Graphics hardware is used to accelerate a technique for generating layered depth images. From multiple layered depth images, a binary volume and a point representation are extracted. The point information is...... iso-surface of the distance field and fit it to the point set. Using this method, one may recover sharp edge information. Examples are given where the method for generating distance fields coupled with mesh fitting is used to perform Boolean and morphological operations on triangle meshes....
Finite Element Meshes Auto-Generation for the Welted Bifurcation
Institute of Scientific and Technical Information of China (English)
YUANMei; LIYa-ping
2004-01-01
In this paper, firstly, a mathematical model for a specific kind of welted bifurcation is established, the parametric equation for the intersecting curve is resulted in. Secondly, a method for partitioning finite element meshes of the welted bifurcation is put forward, its main idea is that developing the main pipe surface and the branch pipe surface respectively, dividing meshes on each developing plane and obtaining meshes points, then transforming their plane coordinates into space coordinates. Finally, an applied program for finite element meshes auto-generation is simply introduced, which adopt ObjectARX technique and its running result can be shown in AutoCAD. The meshes generated in AutoCAD can be exported conveniently to most of finite element analysis soft wares, and the finite element computing result can satisfy the engineering precision requirement.
Delaunay mesh generation for an unstructured-grid ocean general circulation model
Legrand, S.; Legat, V.; E. Deleersnijder
2000-01-01
An incremental method is presented to generate automatically boundary-fitted Delaunay triangulations of the global ocean. The method takes into account Earth curvature and allows local mesh refinement in order to resolve topological or dynamical features like midocean ridges or western boundary currents. Crucial issues like the nodes insertion process, the boundary integrity problem or the creation of inner nodes are explained. Finally, the quality of generated triangulations is discussed.
Using Multi-threading for the Automatic Load Balancing of 2D Adaptive Finite Element Meshes
Heber, Gerd; Biswas, Rupak; Thulasiraman, Parimala; Gao, Guang R.; Saini, Subhash (Technical Monitor)
1998-01-01
In this paper, we present a multi-threaded approach for the automatic load balancing of adaptive finite element (FE) meshes The platform of our choice is the EARTH multi-threaded system which offers sufficient capabilities to tackle this problem. We implement the adaption phase of FE applications oil triangular meshes and exploit the EARTH token mechanism to automatically balance the resulting irregular and highly nonuniform workload. We discuss the results of our experiments oil EARTH-SP2, on implementation of EARTH on the IBM SP2 with different load balancing strategies that are built into the runtime system.
Hexahedral mesh generation via the dual arrangement of surfaces
Energy Technology Data Exchange (ETDEWEB)
Mitchell, S.A.; Tautges, T.J. [Sandia National Labs., Albuquerque, NM (United States)
1997-12-31
Given a general three-dimensional geometry with a prescribed quadrilateral surface mesh, the authors consider the problem of constructing a hexahedral mesh of the geometry whose boundary is exactly the prescribed surface mesh. Due to the specialized topology of hexahedra, this problem is more difficult than the analogous one for tetrahedra. Folklore has maintained that a surface mesh must have a constrained structure in order for there to exist a compatible hexahedral mesh. However, they have proof that a surface mesh need only satisfy mild parity conditions, depending on the topology of the three-dimensional geometry, for there to exist a compatible hexahedral mesh. The proof is based on the realization that a hexahedral mesh is dual to an arrangement of surfaces, and the quadrilateral surface mesh is dual to the arrangement of curves bounding these surfaces. The proof is constructive and they are currently developing an algorithm called Whisker Weaving (WW) that mirrors the proof steps. Given the bounding curves, WW builds the topological structure of an arrangement of surfaces having those curves as its boundary. WW progresses in an advancing front manner. Certain local rules are applied to avoid structures that lead to poor mesh quality. Also, after the arrangement is constructed, additional surfaces are inserted to separate features, so e.g., no two hexahedra share more than one quadrilateral face. The algorithm has generated meshes for certain non-trivial problems, but is currently unreliable. The authors are exploring strategies for consistently selecting which portion of the surface arrangement to advance based on the existence proof. This should lead us to a robust algorithm for arbitrary geometries and surface meshes.
Detecting Translation Errors in CAD Surfaces and Preparing Geometries for Mesh Generation
Energy Technology Data Exchange (ETDEWEB)
Petersson, N Anders; Chand, K K
2001-08-27
The authors have developed tools for the efficient preparation of CAD geometries for mesh generation. Geometries are read from IGES files and then maintained in a boundary-representation consisting of a patchwork of trimmed and untrimmed surfaces. Gross errors in the geometry can be identified and removed automatically while a user interface is provided for manipulating the geometry (such as correcting invalid trimming curves or removing unwanted details). Modifying the geometry by adding or deleting surfaces and/or sectioning it by arbitrary planes (e.g. symmetry planes) is also supported. These tools are used for robust and accurate geometry models for initial mesh generation and will be applied to in situ mesh generation requirements of moving and adaptive grid simulations.
Mesh generation technology for nuclear reactor simulation; barriers and opportunities
International Nuclear Information System (INIS)
Mesh generation in support of nuclear reactor simulation has much in common with the requirements of other application areas, such as computational fluid dynamics (CFD). Indeed, fluid dynamics analysis of the coolant behavior inside the reactor core is an internal flow problem that requires the resolution of spatial and temporal variations in the flow caused by complex component configurations, fluids/structure interaction, turbulence, and thermal heating of the coolant. Typical concerns of meshing complex geometries; the use of hexahedral vs. tetrahedral elements, element geometric quality, mesh smoothness, use of anisotropic elements in the thermal boundary layer, etc., are all considerations important to the reactor meshing problem. Reactor meshing begins to become more specialized as the need to employ reactor simulation as a predictive design and safety analysis capability grows in importance. First, a predictive capability will require more precise physical models to be included, and these models will need to be supported by a computational science framework that will allow them to be accurately approximated both spatially and temporally during the reactor core analysis. Both the multiphysical nature of the composite reactor model and details of the physics algorithms themselves will place new requirements on the meshing process needed to support multidimensional reactor simulation. This article discusses the current state of meshing technology applied to reactor simulation and examines a set of issues that are important in the generation of high-quality reactor meshes today and in the future
Medical Image Processing for Fully Integrated Subject Specific Whole Brain Mesh Generation
Directory of Open Access Journals (Sweden)
Chih-Yang Hsu
2015-05-01
Full Text Available Currently, anatomically consistent segmentation of vascular trees acquired with magnetic resonance imaging requires the use of multiple image processing steps, which, in turn, depend on manual intervention. In effect, segmentation of vascular trees from medical images is time consuming and error prone due to the tortuous geometry and weak signal in small blood vessels. To overcome errors and accelerate the image processing time, we introduce an automatic image processing pipeline for constructing subject specific computational meshes for entire cerebral vasculature, including segmentation of ancillary structures; the grey and white matter, cerebrospinal fluid space, skull, and scalp. To demonstrate the validity of the new pipeline, we segmented the entire intracranial compartment with special attention of the angioarchitecture from magnetic resonance imaging acquired for two healthy volunteers. The raw images were processed through our pipeline for automatic segmentation and mesh generation. Due to partial volume effect and finite resolution, the computational meshes intersect with each other at respective interfaces. To eliminate anatomically inconsistent overlap, we utilized morphological operations to separate the structures with a physiologically sound gap spaces. The resulting meshes exhibit anatomically correct spatial extent and relative positions without intersections. For validation, we computed critical biometrics of the angioarchitecture, the cortical surfaces, ventricular system, and cerebrospinal fluid (CSF spaces and compared against literature values. Volumina and surface areas of the computational mesh were found to be in physiological ranges. In conclusion, we present an automatic image processing pipeline to automate the segmentation of the main intracranial compartments including a subject-specific vascular trees. These computational meshes can be used in 3D immersive visualization for diagnosis, surgery planning with haptics
Automatic generation of tourist brochures
Birsak, Michael
2014-05-01
We present a novel framework for the automatic generation of tourist brochures that include routing instructions and additional information presented in the form of so-called detail lenses. The first contribution of this paper is the automatic creation of layouts for the brochures. Our approach is based on the minimization of an energy function that combines multiple goals: positioning of the lenses as close as possible to the corresponding region shown in an overview map, keeping the number of lenses low, and an efficient numbering of the lenses. The second contribution is a route-aware simplification of the graph of streets used for traveling between the points of interest (POIs). This is done by reducing the graph consisting of all shortest paths through the minimization of an energy function. The output is a subset of street segments that enable traveling between all the POIs without considerable detours, while at the same time guaranteeing a clutter-free visualization. © 2014 The Author(s) Computer Graphics Forum © 2014 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.
Automatic Tooth Segmentation of Dental Mesh Based on Harmonic Fields
Sheng-hui Liao; Shi-jian Liu; Bei-ji Zou; Xi Ding; Ye Liang; Jun-hui Huang
2015-01-01
An important preprocess in computer-aided orthodontics is to segment teeth from the dental models accurately, which should involve manual interactions as few as possible. But fully automatic partition of all teeth is not a trivial task, since teeth occur in different shapes and their arrangements vary substantially from one individual to another. The difficulty is exacerbated when severe teeth malocclusion and crowding problems occur, which is a common occurrence in clinical cases. Most publi...
International Nuclear Information System (INIS)
In an attempt to automatically produce high-quality all-hex meshes, we investigated a mesh improvement strategy: given an initial poor-quality all-hex mesh, we iteratively changed the element connectivity, adding and deleting elements and nodes, and optimized the node positions. We found a set of hex reconnection primitives. We improved the optimization algorithms so they can untangle a negative-Jacobian mesh, even considering Jacobians on the boundary, and subsequently optimize the condition number of elements in an untangled mesh. However, even after applying both the primitives and optimization we were unable to produce high-quality meshes in certain regions. Our experiences suggest that many boundary configurations of quadrilaterals admit no hexahedral mesh with positive Jacobians, although we have no proof of this
Directory of Open Access Journals (Sweden)
Chi Wan Lim
Full Text Available We propose an automatic algorithm for the reconstruction of patient-specific cardiac mesh models with 1-to-1 vertex correspondence. In this framework, a series of 3D meshes depicting the endocardial surface of the heart at each time step is constructed, based on a set of border delineated magnetic resonance imaging (MRI data of the whole cardiac cycle. The key contribution in this work involves a novel reconstruction technique to generate a 4D (i.e., spatial-temporal model of the heart with 1-to-1 vertex mapping throughout the time frames. The reconstructed 3D model from the first time step is used as a base template model and then deformed to fit the segmented contours from the subsequent time steps. A method to determine a tree-based connectivity relationship is proposed to ensure robust mapping during mesh deformation. The novel feature is the ability to handle intra- and inter-frame 2D topology changes of the contours, which manifests as a series of merging and splitting of contours when the images are viewed either in a spatial or temporal sequence. Our algorithm has been tested on five acquisitions of cardiac MRI and can successfully reconstruct the full 4D heart model in around 30 minutes per subject. The generated 4D heart model conforms very well with the input segmented contours and the mesh element shape is of reasonably good quality. The work is important in the support of downstream computational simulation activities.
ORMGEN3D, 3-D Crack Geometry FEM Mesh Generator
International Nuclear Information System (INIS)
1 - Description of program or function: ORMGEN3D is a finite element mesh generator for computational fracture mechanics analysis. The program automatically generates a three-dimensional finite element model for six different crack geometries. These geometries include flat plates with straight or curved surface cracks and cylinders with part-through cracks on the outer or inner surface. Mathematical or user-defined crack shapes may be considered. The curved cracks may be semicircular, semi-elliptical, or user-defined. A cladding option is available that allows for either an embedded or penetrating crack in the clad material. 2 - Method of solution: In general, one eighth or one-quarter of the structure is modelled depending on the configuration or option selected. The program generates a core of special wedge or collapsed prism elements at the crack front to introduce the appropriate stress singularity at the crack tip. The remainder of the structure is modelled with conventional 20-node iso-parametric brick elements. Element group I of the finite element model consists of an inner core of special crack tip elements surrounding the crack front enclosed by a single layer of conventional brick elements. Eight element divisions are used in a plane orthogonal to the crack front, while the number of element divisions along the arc length of the crack front is user-specified. The remaining conventional brick elements of the model constitute element group II. 3 - Restrictions on the complexity of the problem: Maxima of 5,500 nodes, 4 layers of clad elements
Robust Generation of Signed Distance Fields from Triangle Meshes
DEFF Research Database (Denmark)
Bærentzen, Jakob Andreas
2005-01-01
A new method for robust generation of distance fields from triangle meshes is presented. Graphics hardware is used to accelerate a technique for generating layered depth images. From multiple layered depth images, a binary volume and a point representation are extracted. The point information is...... then used to convert the binary volume into a distance field. The method is robust and handles holes, spurious triangles and ambiguities. Moreover, the method lends itself to Boolean operations between solids. Since a point cloud as well as a signed distance is generated, it is possible to extract an...... iso-surface of the distance field and fit it to the point set. Using this method, one may recover sharp edge information. Examples are given where the method for generating distance fields coupled with mesh fitting is used to perform Boolean and morphological operations on triangle meshes....
Adaptive mesh refinement and automatic remeshing in crystal plasticity finite element simulations
International Nuclear Information System (INIS)
In finite element simulations dedicated to the modelling of microstructure evolution, the mesh has to be fine enough to: (i) accurately describe the geometry of the constituents; (ii) capture local strain gradients stemming from the heterogeneity in material properties. In this paper, 3D polycrystalline aggregates are discretized into unstructured meshes and a level set framework is used to represent the grain boundaries. The crystal plasticity finite element method is used to simulate the plastic deformation of these aggregates. A mesh sensitivity analysis based on the deformation energy distribution shows that the predictions are, on average, more sensitive near grain boundaries. An anisotropic mesh refinement strategy based on the level set description is introduced and it is shown that it offers a good compromise between accuracy requirements on the one hand and computation time on the other hand. As the aggregates deform, mesh distortion inevitably occurs and ultimately causes the breakdown of the simulations. An automatic remeshing tool is used to periodically reconstruct the mesh and appropriate transfer of state variables is performed. It is shown that the diffusion related to data transfer is not significant. Finally, remeshing is performed repeatedly in a highly resolved 500 grains polycrystal subjected to about 90% thickness reduction in rolling. The predicted texture is compared with the experimental data and with the predictions of a standard Taylor model
Development of unstructured mesh generator on parallel computers
International Nuclear Information System (INIS)
A general-purpose unstructured mesh generator, 'GRID3D/UNST', has been developed on parallel computers. High-speed operations and large-scale memory capacity of parallel computers enable the system to generate a large-scale mesh at high speed. As a matter of fact, the system generates large-scale mesh composed of 2,400,000 nodes and 14,000,000 elements about 1.5 hours on HITACHI SR2201, 64 PEs (Processing Elements) through 2.5 hours pre-process on SUN. Also the system is built on standard FORTRAN, C and Motif, and therefore has high portability. The system enables us to solve a large-scale problem that has been impossible to be solved, and to break new ground in the field of science and engineering. (author)
Generating Signed Distance Fields From Triangle Meshes
DEFF Research Database (Denmark)
Bærentzen, Jakob Andreas; Aanæs, Henrik
A method for generating a discrete, signed 3D distance field is proposed. Distance fields are used in a number of contexts. In particular the popular level set method is usually initialized by a distance field. The main focus of our work is on simplifying the computation of the sign when generating...... leads to a method for generating signed distance fields which is a simple and straightforward extension of the method for generating unsigned distance fields. We prove that our choice of pseudo normal leads to a correct technique for computing the sign....
Traceability Through Automatic Program Generation
Richardson, Julian; Green, Jeff
2003-01-01
Program synthesis is a technique for automatically deriving programs from specifications of their behavior. One of the arguments made in favour of program synthesis is that it allows one to trace from the specification to the program. One way in which traceability information can be derived is to augment the program synthesis system so that manipulations and calculations it carries out during the synthesis process are annotated with information on what the manipulations and calculations were and why they were made. This information is then accumulated throughout the synthesis process, at the end of which, every artifact produced by the synthesis is annotated with a complete history relating it to every other artifact (including the source specification) which influenced its construction. This approach requires modification of the entire synthesis system - which is labor-intensive and hard to do without influencing its behavior. In this paper, we introduce a novel, lightweight technique for deriving traceability from a program specification to the corresponding synthesized code. Once a program has been successfully synthesized from a specification, small changes are systematically made to the specification and the effects on the synthesized program observed. We have partially automated the technique and applied it in an experiment to one of our program synthesis systems, AUTOFILTER, and to the GNU C compiler, GCC. The results are promising: 1. Manual inspection of the results indicates that most of the connections derived from the source (a specification in the case of AUTOFILTER, C source code in the case of GCC) to its generated target (C source code in the case of AUTOFILTER, assembly language code in the case of GCC) are correct. 2. Around half of the lines in the target can be traced to at least one line of the source. 3. Small changes in the source often induce only small changes in the target.
Computational mesh generation for vascular structures with deformable surfaces
International Nuclear Information System (INIS)
Computational blood flow and vessel wall mechanics simulations for vascular structures are becoming an important research tool for patient-specific surgical planning and intervention. An important step in the modelling process for patient-specific simulations is the creation of the computational mesh based on the segmented geometry. Most known solutions either require a large amount of manual processing or lead to a substantial difference between the segmented object and the actual computational domain. We have developed a chain of algorithms that lead to a closely related implementation of image segmentation with deformable models and 3D mesh generation. The resulting processing chain is very robust and leads both to an accurate geometrical representation of the vascular structure as well as high quality computational meshes. The chain of algorithms has been tested on a wide variety of shapes. A benchmark comparison of our mesh generation application with five other available meshing applications clearly indicates that the new approach outperforms the existing methods in the majority of cases. (orig.)
Pavarino, E; Neves, L A; Machado, J M; de Godoy, M F; Shiyou, Y; Momente, J C; Zafalon, G F D; Pinto, A R; Valêncio, C R
2013-01-01
The Finite Element Method is a well-known technique, being extensively applied in different areas. Studies using the Finite Element Method (FEM) are targeted to improve cardiac ablation procedures. For such simulations, the finite element meshes should consider the size and histological features of the target structures. However, it is possible to verify that some methods or tools used to generate meshes of human body structures are still limited, due to nondetailed models, nontrivial preprocessing, or mainly limitation in the use condition. In this paper, alternatives are demonstrated to solid modeling and automatic generation of highly refined tetrahedral meshes, with quality compatible with other studies focused on mesh generation. The innovations presented here are strategies to integrate Open Source Software (OSS). The chosen techniques and strategies are presented and discussed, considering cardiac structures as a first application context. PMID:23762031
Aranha: a 2D mesh generator for triangular finite elements
International Nuclear Information System (INIS)
A method for generating unstructured meshes for linear and quadratic triangular finite elements is described in this paper. Some topics on the C language data structure used in the development of the program Aranha are also presented. The applicability for adaptive remeshing is shown and finally several examples are included to illustrate the performance of the method in irregular connected planar domains. (author)
Automatic mesh adaptivity for CADIS and FW-CADIS neutronics modeling of difficult shielding problems
International Nuclear Information System (INIS)
The CADIS and FW-CADIS hybrid Monte Carlo/deterministic techniques dramatically increase the efficiency of neutronics modeling, but their use in the accurate design analysis of very large and geometrically complex nuclear systems has been limited by the large number of processors and memory requirements for their preliminary deterministic calculations and final Monte Carlo calculation. Three mesh adaptivity algorithms were developed to reduce the memory requirements of CADIS and FW-CADIS without sacrificing their efficiency improvement. First, a macro-material approach enhances the fidelity of the deterministic models without changing the mesh. Second, a deterministic mesh refinement algorithm generates meshes that capture as much geometric detail as possible without exceeding a specified maximum number of mesh elements. Finally, a weight window coarsening algorithm de-couples the weight window mesh and energy bins from the mesh and energy group structure of the deterministic calculations in order to remove the memory constraint of the weight window map from the deterministic mesh resolution. The three algorithms were used to enhance an FW-CADIS calculation of the prompt dose rate throughout the ITER experimental facility. Using these algorithms resulted in a 23.3% increase in the number of mesh tally elements in which the dose rates were calculated in a 10-day Monte Carlo calculation and, additionally, increased the efficiency of the Monte Carlo simulation by a factor of at least 3.4. The three algorithms enabled this difficult calculation to be accurately solved using an FW-CADIS simulation on a regular computer cluster, obviating the need for a world-class super computer. (authors)
Conforming restricted Delaunay mesh generation for piecewise smooth complexes
Engwirda, Darren
2016-01-01
A Frontal-Delaunay refinement algorithm for mesh generation in piecewise smooth domains is described. Built using a restricted Delaunay framework, this new algorithm combines a number of novel features, including: (i) a consistent, conforming restricted Delaunay representation for domains specified as a (non-manifold) collection of piecewise smooth surface patches and curve constraints, (ii) a `protection' strategy for domains containing 1-dimensional features that meet at sharply acute angle...
AUTOMATIC CAPTION GENERATION FOR ELECTRONICS TEXTBOOKS
Veena Thakur; Trupti Gedam
2015-01-01
Automatic or semi-automatic approaches for developing Technology Supported Learning Systems (TSLS) are required to lighten their development cost. The main objective of this paper is to automate the generation of a caption module; it aims at reproducing the way teachers prepare their lessons and the learning material they will use throughout the course. Teachers tend to choose one or more textbooks that cover the contents of their subjects, determine the topics to be addressed, and identify...
The ACR-program for automatic finite element model generation for part through cracks
International Nuclear Information System (INIS)
The ACR-program (Automatic Finite Element Model Generation for Part Through Cracks) has been developed at the Technical Research Centre of Finland (VTT) for automatic finite element model generation for surface flaws using three dimensional solid elements. Circumferential or axial cracks can be generated on the inner or outer surface of a cylindrical or toroidal geometry. Several crack forms are available including the standard semi-elliptical surface crack. The program can be used in the development of automated systems for fracture mechanical analyses of structures. The tests for the accuracy of the FE-mesh have been started with two-dimensional models. The results indicate that the accuracy of the standard mesh is sufficient for practical analyses. Refinement of the standard mesh is needed in analyses with high load levels well over the limit load of the structure
Terrain-driven unstructured mesh development through semi-automatic vertical feature extraction
Bilskie, Matthew V.; Coggin, David; Hagen, Scott C.; Medeiros, Stephen C.
2015-12-01
validation techniques are necessary for state-of-the-art flood inundation models. In addition, the semi-automated, unstructured mesh generation process presented herein increases the overall accuracy of simulated storm surge across the floodplain without reliance on hand digitization or sacrificing computational cost.
Automatic generation of multilingual sports summaries
Hasan, Fahim Muhammad
2011-01-01
Natural Language Generation is a subfield of Natural Language Processing, which is concerned with automatically creating human readable text from non-linguistic forms of information. A template-based approach to Natural Language Generation utilizes base formats for different types of sentences, which are subsequently transformed to create the final readable forms of the output. In this thesis, we investigate the suitability of a template-based approach to multilingual Natural Language Generat...
MESH2D GRID GENERATOR DESIGN AND USE
Energy Technology Data Exchange (ETDEWEB)
Flach, G.; Smith, F.
2012-01-20
Mesh2d is a Fortran90 program designed to generate two-dimensional structured grids of the form [x(i),y(i,j)] where [x,y] are grid coordinates identified by indices (i,j). The x(i) coordinates alone can be used to specify a one-dimensional grid. Because the x-coordinates vary only with the i index, a two-dimensional grid is composed in part of straight vertical lines. However, the nominally horizontal y(i,j{sub 0}) coordinates along index i are permitted to undulate or otherwise vary. Mesh2d also assigns an integer material type to each grid cell, mtyp(i,j), in a user-specified manner. The complete grid is specified through three separate input files defining the x(i), y(i,j), and mtyp(i,j) variations. The overall mesh is constructed from grid zones that are typically then subdivided into a collection of smaller grid cells. The grid zones usually correspond to distinct materials or larger-scale geometric shapes. The structured grid zones are identified through uppercase indices (I,J). Subdivision of zonal regions into grid cells can be done uniformly, or nonuniformly using either a polynomial or geometric skewing algorithm. Grid cells may be concentrated backward, forward, or toward both ends. Figure 1 illustrates the above concepts in the context of a simple four zone grid.
Exploiting MeSH indexing in MEDLINE to generate a data set for word sense disambiguation
Directory of Open Access Journals (Sweden)
McInnes Bridget T
2011-06-01
Full Text Available Abstract Background Evaluation of Word Sense Disambiguation (WSD methods in the biomedical domain is difficult because the available resources are either too small or too focused on specific types of entities (e.g. diseases or genes. We present a method that can be used to automatically develop a WSD test collection using the Unified Medical Language System (UMLS Metathesaurus and the manual MeSH indexing of MEDLINE. We demonstrate the use of this method by developing such a data set, called MSH WSD. Methods In our method, the Metathesaurus is first screened to identify ambiguous terms whose possible senses consist of two or more MeSH headings. We then use each ambiguous term and its corresponding MeSH heading to extract MEDLINE citations where the term and only one of the MeSH headings co-occur. The term found in the MEDLINE citation is automatically assigned the UMLS CUI linked to the MeSH heading. Each instance has been assigned a UMLS Concept Unique Identifier (CUI. We compare the characteristics of the MSH WSD data set to the previously existing NLM WSD data set. Results The resulting MSH WSD data set consists of 106 ambiguous abbreviations, 88 ambiguous terms and 9 which are a combination of both, for a total of 203 ambiguous entities. For each ambiguous term/abbreviation, the data set contains a maximum of 100 instances per sense obtained from MEDLINE. We evaluated the reliability of the MSH WSD data set using existing knowledge-based methods and compared their performance to that of the results previously obtained by these algorithms on the pre-existing data set, NLM WSD. We show that the knowledge-based methods achieve different results but keep their relative performance except for the Journal Descriptor Indexing (JDI method, whose performance is below the other methods. Conclusions The MSH WSD data set allows the evaluation of WSD algorithms in the biomedical domain. Compared to previously existing data sets, MSH WSD contains a larger
Techniques on mesh generation for the brain shift simulation
Lobos, Claudio; Payan, Yohan; Hitschfeld, Nancy
2007-01-01
Neurosurgery interventions involve complex tracking systems because a tissue deformation takesplace. The neuronavigation system relies only on preoperative images. In order to overcome the soft tissue deformations and guarantee the accuracy of the navigation a biomechanical model can be used during surgery to simulate the deformation of the brain. Therefore, a mesh generation for an optimal real-time Finite Element Model (FEM) becomes crucial. In this work we present different alternatives from a meshgeneration point of view that were evaluated to optimize the process in terms of elements quantity and quality as well as constraints of a intraoperative application and patient specific data.
Generating Semi-Markov Models Automatically
Johnson, Sally C.
1990-01-01
Abstract Semi-Markov Specification Interface to SURE Tool (ASSIST) program developed to generate semi-Markov model automatically from description in abstract, high-level language. ASSIST reads input file describing failure behavior of system in abstract language and generates Markov models in format needed for input to Semi-Markov Unreliability Range Evaluator (SURE) program (COSMIC program LAR-13789). Facilitates analysis of behavior of fault-tolerant computer. Written in PASCAL.
A Novel Tetrahedral Mesh Generation Method for Rotating Machines Including End-Coil Region
Yamashita, Hideo; Yamaji, Akihisa; Cingoski, Vlatko; Kaneda, Kazufumi
1996-01-01
In this paper, a novel method for generating tetrahedral finite-element meshes suitable for 3-D finite element analysis of rotating machines is presented. The proposed method enables the easy development of 3-D meshes for various rotating machines, especially in the end-coil region and the surrounding air region. Tessellation of the 3-D region is made possible by simple extension of a previously generated 2-D triangular mesh, used as a model mesh, into the third dimension.
A GENERATIVE CAD MODEL OF A WORM GEAR MESHING
Directory of Open Access Journals (Sweden)
Angelika WRONKOWICZ
2014-03-01
Full Text Available This article introduces the term of a generative CAD model, its origins and, thus, a need of creating such a type of models. A process of generative model creation as well as specific forms of knowledge recording applied in the implementation phase in various CAD systems are briefly discussed. The example of a worm gear meshing realized by the CATIA software encapsulates the methodology of generative model construction. Sources and types of knowledge for design and construction required for development of the aforementioned model as well as the UML language as a method of formal knowledge recording are presented. The concept of model creation, i.e. assumptions and the structure as well as logic of the model operation are described. Also, the paper addresses selected elements of the project that present the manner in which the model was constructed.
Unstructured Mesh Movement and Viscous Mesh Generation for CFD-Based Design Optimization Project
National Aeronautics and Space Administration — The innovations proposed are twofold: 1) a robust unstructured mesh movement method able to handle isotropic (Euler), anisotropic (viscous), mixed element (hybrid)...
Group-wise automatic mesh-based analysis of cortical thickness
Vachet, Clement; Cody Hazlett, Heather; Niethammer, Marc; Oguz, Ipek; Cates, Joshua; Whitaker, Ross; Piven, Joseph; Styner, Martin
2011-03-01
The analysis of neuroimaging data from pediatric populations presents several challenges. There are normal variations in brain shape from infancy to adulthood and normal developmental changes related to tissue maturation. Measurement of cortical thickness is one important way to analyze such developmental tissue changes. We developed a novel framework that allows group-wise automatic mesh-based analysis of cortical thickness. Our approach is divided into four main parts. First an individual pre-processing pipeline is applied on each subject to create genus-zero inflated white matter cortical surfaces with cortical thickness measurements. The second part performs an entropy-based group-wise shape correspondence on these meshes using a particle system, which establishes a trade-off between an even sampling of the cortical surfaces and the similarity of corresponding points across the population using sulcal depth information and spatial proximity. A novel automatic initial particle sampling is performed using a matched 98-lobe parcellation map prior to a particle-splitting phase. Third, corresponding re-sampled surfaces are computed with interpolated cortical thickness measurements, which are finally analyzed via a statistical vertex-wise analysis module. This framework consists of a pipeline of automated 3D Slicer compatible modules. It has been tested on a small pediatric dataset and incorporated in an open-source C++ based high-level module called GAMBIT. GAMBIT's setup allows efficient batch processing, grid computing and quality control. The current research focuses on the use of an average template for correspondence and surface re-sampling, as well as thorough validation of the framework and its application to clinical pediatric studies.
Moving mesh generation with a sequential approach for solving PDEs
DEFF Research Database (Denmark)
physical and mesh equations suffers typically from long computation time due to highly nonlinear coupling between the two equations. Moreover, the extended system (physical and mesh equations) may be sensitive to the tuning parameters such as a temporal relaxation factor. It is therefore useful to design a......In moving mesh methods, physical PDEs and a mesh equation derived from equidistribution of an error metrics (so-called the monitor function) are simultaneously solved and meshes are dynamically concentrated on steep regions (Lim et al., 2001). However, the simultaneous solution procedure of...... adaptive grid method (local refinement by adding/deleting the meshes at a discrete time level) as well as of efficiency for the dynamic adaptive grid method (or moving mesh method) where the number of meshes is not changed. For illustration, a phase change problem is solved with the decomposition algorithm....
Automatic Test Pattern Generation for Digital Circuits
Directory of Open Access Journals (Sweden)
S. Hemalatha
2014-04-01
Full Text Available Digital circuits complexity and density are increasing and at the same time it should have more quality and reliability. It leads with high test costs and makes the validation more complex. The main aim is to develop a complete behavioral fault simulation and automatic test pattern generation (ATPG system for digital circuits modeled in verilog and VHDL. An integrated Automatic Test Generation (ATG and Automatic Test Executing/Equipment (ATE system for complex boards is developed here. An approach to use memristors (resistors with memory in programmable analog circuits. The Main idea consists in a circuit design in which low voltages are applied to memristors during their operation as analog circuit elements and high voltages are used to program the memristor’s states. This way, as it was demonstrated in recent experiments, the state of memristors does not essentially change during analog mode operation. As an example of our approach, we have built several programmable analog circuits demonstrating memristor -based programming of threshold, gain and frequency. In these circuits the role of memristor is played by a memristor emulator developed by us. A multiplexer is developed to generate a class of minimum transition sequences. The entire hardware is realized as digital logical circuits and the test results are simulated in Model sim software. The results of this research show that behavioral fault simulation will remain as a highly attractive alternative for the future generation of VLSI and system-on-chips (SoC.
Different Manhattan project: automatic statistical model generation
Yap, Chee Keng; Biermann, Henning; Hertzmann, Aaron; Li, Chen; Meyer, Jon; Pao, Hsing-Kuo; Paxia, Salvatore
2002-03-01
We address the automatic generation of large geometric models. This is important in visualization for several reasons. First, many applications need access to large but interesting data models. Second, we often need such data sets with particular characteristics (e.g., urban models, park and recreation landscape). Thus we need the ability to generate models with different parameters. We propose a new approach for generating such models. It is based on a top-down propagation of statistical parameters. We illustrate the method in the generation of a statistical model of Manhattan. But the method is generally applicable in the generation of models of large geographical regions. Our work is related to the literature on generating complex natural scenes (smoke, forests, etc) based on procedural descriptions. The difference in our approach stems from three characteristics: modeling with statistical parameters, integration of ground truth (actual map data), and a library-based approach for texture mapping.
Linguistics Computation, Automatic Model Generation, and Intensions
Nourani, Cyrus F.
1994-01-01
Techniques are presented for defining models of computational linguistics theories. The methods of generalized diagrams that were developed by this author for modeling artificial intelligence planning and reasoning are shown to be applicable to models of computation of linguistics theories. It is shown that for extensional and intensional interpretations, models can be generated automatically which assign meaning to computations of linguistics theories for natural languages. Keywords: Computa...
XML-Based Automatic Test Data Generation
Halil Ibrahim Bulbul; Turgut Bakir
2012-01-01
Software engineering aims at increasing quality and reliability while decreasing the cost of the software. Testing is one of the most time-consuming phases of the software development lifecycle. Improvement in software testing results in decrease in cost and increase in quality of the software. Automation in software testing is one of the most popular ways of software cost reduction and reliability improvement. In our work we propose a system called XML-based automatic test data generation th...
Automatic Caption Generation for Electronics Textbooks
Directory of Open Access Journals (Sweden)
Veena Thakur
2014-12-01
Full Text Available Automatic or semi-automatic approaches for developing Technology Supported Learning Systems (TSLS are required to lighten their development cost. The main objective of this paper is to automate the generation of a caption module; it aims at reproducing the way teachers prepare their lessons and the learning material they will use throughout the course. Teachers tend to choose one or more textbooks that cover the contents of their subjects, determine the topics to be addressed, and identify the parts of the textbooks which may be helpful for the students it describes the entities, attributes, role and their relationship plus the constraints that govern the problem domain. The caption model is created in order to represent the vocabulary and key concepts of the problem domain. The caption model also identifies the relationships among all the entities within the scope of the problem domain, and commonly identifies their attributes. It defines a vocabulary and is helpful as a communication tool. DOM-Sortze, a framework that enables the semi-automatic generation of the Caption Module for technology supported learning system (TSLS from electronic textbooks. The semiautomatic generation of the Caption Module entails the identification and elicitation of knowledge from the documents to which end Natural Language Processing (NLP techniques are combined with ontologies and heuristic reasoning.
AUTOMATIC CAPTION GENERATION FOR ELECTRONICS TEXTBOOKS
Directory of Open Access Journals (Sweden)
Veena Thakur
2015-10-01
Full Text Available Automatic or semi-automatic approaches for developing Technology Supported Learning Systems (TSLS are required to lighten their development cost. The main objective of this paper is to automate the generation of a caption module; it aims at reproducing the way teachers prepare their lessons and the learning material they will use throughout the course. Teachers tend to choose one or more textbooks that cover the contents of their subjects, determine the topics to be addressed, and identify the parts of the textbooks which may be helpful for the students it describes the entities, attributes, role and their relationship plus the constraints that govern the problem domain. The caption model is created in order to represent the vocabulary and key concepts of the problem domain. The caption model also identifies the relationships among all the entities within the scope of the problem domain, and commonly identifies their attributes. It defines a vocabulary and is helpful as a communication tool. DOM-Sortze, a framework that enables the semi-automatic generation of the Caption Module for technology supported learning system (TSLS from electronic textbooks. The semiautomatic generation of the Caption Module entails the identification and elicitation of knowledge from the documents to which end Natural Language Processing (NLP techniques are combined with ontologies and heuristic reasoning.
Semi-automatic construction of the Chinese-English MeSH using Web-based term translation method.
Lu, Wen-Hsiang; Lin, Shih-Jui; Chan, Yi-Che; Chen, Kuan-Hsi
2005-01-01
Due to language barrier, non-English users are unable to retrieve the most updated medical information from the U.S. authoritative medical websites, such as PubMed and MedlinePlus. A few cross-language medical information retrieval (CLMIR) systems have been utilizing MeSH (Medical Subject Heading) with multilingual thesaurus to bridge the gap. Unfortunately, MeSH has yet not been translated into traditional Chinese currently. We proposed a semi-automatic approach to constructing Chinese-English MeSH based on Web-based term translation. The system provides knowledge engineers with candidate terms mining from anchor texts and search-result pages. The result is encouraging. Currently, more than 19,000 Chinese-English MeSH entries have been complied. This thesaurus will be used in Chinese-English CLMIR in the future. PMID:16779085
Automatic generation of combinatorial test data
Zhang, Jian; Ma, Feifei
2014-01-01
This book reviews the state-of-the-art in combinatorial testing, with particular emphasis on the automatic generation of test data. It describes the most commonly used approaches in this area - including algebraic construction, greedy methods, evolutionary computation, constraint solving and optimization - and explains major algorithms with examples. In addition, the book lists a number of test generation tools, as well as benchmarks and applications. Addressing a multidisciplinary topic, it will be of particular interest to researchers and professionals in the areas of software testing, combi
Automatic generation of simple (statistical) exams
Grün, Bettina; Zeileis, Achim
2008-01-01
Package exams provides a framework for automatic generation of simple (statistical) exams. To employ the tools, users just need to supply a pool of exercises and a master file controlling the layout of the final PDF document. The exercises are specified in separate Sweave files (containing R code for data generation and LaTeX code for problem and solution description) and the master file is a LaTeX document with some additional control commands. This paper gives an overview on the main design...
Papadakis, A. P.; Georghiou, G. E.; Metaxas, A. C.
2008-12-01
A new adaptive mesh generator has been developed and used in the analysis of high-pressure gas discharges, such as avalanches and streamers, reducing computational times and computer memory needs significantly. The new adaptive mesh generator developed, uses normalized error indicators, varying from 0 to 1, to guarantee optimal mesh resolution for all carriers involved in the analysis. Furthermore, it uses h- and r-refinement techniques such as mesh jiggling, edge swapping and node addition/removal to develop an element quality improvement algorithm that improves the mesh quality significantly and a fast and accurate algorithm for interpolation between meshes. Finally, the mesh generator is applied in the characterization of the transition from a single electron to the avalanche and streamer discharges in high-voltage, high-pressure gas discharges for dc 1 mm gaps, RF 1 cm point-plane gaps and parallel-plate 40 MHz configurations, in ambient atmospheric air.
Energy Technology Data Exchange (ETDEWEB)
Papadakis, A P [Department of Electrical Engineering, Frederick University Cyprus, 7 Y Frederickou Street, Palouriotissa, Nicosia 1036 (Cyprus); Georghiou, G E [Department of Electrical and Computer Engineering, University of Cyprus, 75 Kallipoleos, PO Box 20577, 1678, Nicosia (Cyprus); Metaxas, A C [St John' s College, University of Cambridge, Cambridge, CB2 1TP (United Kingdom)], E-mail: eng.ap@frederick.ac.cy, E-mail: geg@ucy.ac.cy, E-mail: acm33@cam.ac.uk
2008-12-07
A new adaptive mesh generator has been developed and used in the analysis of high-pressure gas discharges, such as avalanches and streamers, reducing computational times and computer memory needs significantly. The new adaptive mesh generator developed, uses normalized error indicators, varying from 0 to 1, to guarantee optimal mesh resolution for all carriers involved in the analysis. Furthermore, it uses h- and r-refinement techniques such as mesh jiggling, edge swapping and node addition/removal to develop an element quality improvement algorithm that improves the mesh quality significantly and a fast and accurate algorithm for interpolation between meshes. Finally, the mesh generator is applied in the characterization of the transition from a single electron to the avalanche and streamer discharges in high-voltage, high-pressure gas discharges for dc 1 mm gaps, RF 1 cm point-plane gaps and parallel-plate 40 MHz configurations, in ambient atmospheric air.
Efficient computation of clipped Voronoi diagram for mesh generation
Yan, Dongming
2013-04-01
The Voronoi diagram is a fundamental geometric structure widely used in various fields, especially in computer graphics and geometry computing. For a set of points in a compact domain (i.e. a bounded and closed 2D region or a 3D volume), some Voronoi cells of their Voronoi diagram are infinite or partially outside of the domain, but in practice only the parts of the cells inside the domain are needed, as when computing the centroidal Voronoi tessellation. Such a Voronoi diagram confined to a compact domain is called a clipped Voronoi diagram. We present an efficient algorithm to compute the clipped Voronoi diagram for a set of sites with respect to a compact 2D region or a 3D volume. We also apply the proposed method to optimal mesh generation based on the centroidal Voronoi tessellation. Crown Copyright © 2011 Published by Elsevier Ltd. All rights reserved.
Automatic Metadata Generation using Associative Networks
Rodriguez, Marko A; Van de Sompel, Herbert
2008-01-01
In spite of its tremendous value, metadata is generally sparse and incomplete, thereby hampering the effectiveness of digital information services. Many of the existing mechanisms for the automated creation of metadata rely primarily on content analysis which can be costly and inefficient. The automatic metadata generation system proposed in this article leverages resource relationships generated from existing metadata as a medium for propagation from metadata-rich to metadata-poor resources. Because of its independence from content analysis, it can be applied to a wide variety of resource media types and is shown to be computationally inexpensive. The proposed method operates through two distinct phases. Occurrence and co-occurrence algorithms first generate an associative network of repository resources leveraging existing repository metadata. Second, using the associative network as a substrate, metadata associated with metadata-rich resources is propagated to metadata-poor resources by means of a discrete...
Automatic code generation for distributed robotic systems
International Nuclear Information System (INIS)
Hetero Helix is a software environment which supports relatively large robotic system development projects. The environment supports a heterogeneous set of message-passing LAN-connected common-bus multiprocessors, but the programming model seen by software developers is a simple shared memory. The conceptual simplicity of shared memory makes it an extremely attractive programming model, especially in large projects where coordinating a large number of people can itself become a significant source of complexity. We present results from three system development efforts conducted at Oak Ridge National Laboratory over the past several years. Each of these efforts used automatic software generation to create 10 to 20 percent of the system
Automatic Quiz Generation for the Elderly.
Chen, Weiqin; Samuelsen, Jeanette
2015-01-01
According to the literature, ageing causes declines in sensory, perceptual, motor and cognitive abilities. The combination of reduced vision, hearing, memory and mobility contributes to isolation and depression. We argue that memory games have potential for enhancing the cognitive ability of the elderly and improving their life quality. In our earlier research, we designed tangible tabletop games to help the elderly remember and talk about the past. In this paper, we report on our further research in the automatic generation of quizzes based on Wikipedia and other online resources for entertainment and memory training of the elderly. PMID:26294527
h-Adaptive Mesh Generation using Electric Field Intensity Value as a Criterion (in Japanese)
Toyonaga, Kiyomi; Cingoski, Vlatko; Kaneda, Kazufumi; Yamashita, Hideo
1994-01-01
Finite mesh divisions are essential to obtain accurate solution of two dimensional electric field analysis. It requires the technical knowledge to generate a suitable fine mesh divisions. In electric field problem, analysts are usually interested in the electric field intensity and its distribution. In order to obtain electric field intensity with high-accuracy, we have developed and adaptive mesh generator using electric field intensity value as a criterion.
New Software Developments for Quality Mesh Generation and Optimization from Biomedical Imaging Data
Yu, Zeyun; Wang, Jun; Gao, Zhanheng; Xu, Ming; Hoshijima, Masahiko
2013-01-01
In this paper we present a new software toolkit for generating and optimizing surface and volumetric meshes from three-dimensional (3D) biomedical imaging data, targeted at image-based finite element analysis of some biomedical activities in a single material domain. Our toolkit includes a series of geometric processing algorithms including surface re-meshing and quality-guaranteed tetrahedral mesh generation and optimization. All methods described have been encapsulated into a user-friendly ...
Pamgen, a library for parallel generation of simple finite element meshes.
Energy Technology Data Exchange (ETDEWEB)
Foucar, James G.; Drake, Richard Roy; Hensinger, David M.; Gardiner, Thomas Anthony
2008-04-01
Generating finite-element meshes is a serious bottleneck for large parallel simulations. When mesh generation is limited to serial machines and element counts approach a billion, this bottleneck becomes a roadblock. Pamgen is a parallel mesh generation library that allows on-the-fly scalable generation of hexahedral and quadrilateral finite element meshes for several simple geometries. It has been used to generate more that 1.1 billion elements on 17,576 processors. Pamgen generates an unstructured finite element mesh on each processor at the start of a simulation. The mesh is specified by commands passed to the library as a 'C'-programming language string. The resulting mesh geometry, topology, and communication information can then be queried through an API. pamgen allows specification of boundary condition application regions using sidesets (element faces) and nodesets (collections of nodes). It supports several simple geometry types. It has multiple alternatives for mesh grading. It has several alternatives for the initial domain decomposition. Pamgen makes it easy to change details of the finite element mesh and is very useful for performance studies and scoping calculations.
Challenges in Second-Generation Wireless Mesh Networks
Directory of Open Access Journals (Sweden)
Thomas Huehn
2008-10-01
Full Text Available Wireless mesh networks have the potential to provide ubiquitous high-speed Internet access at low costs. The good news is that initial deployments of WiFi meshes show the feasibility of providing ubiquitous Internet connectivity. However, their performance is far below the necessary and achievable limit. Moreover, users' subscription in the existing meshes is dismal even though the technical challenges to get connectivity are low. This paper provides an overview of the current status of mesh networks' deployment, and highlights the technical, economical, and social challenges that need to be addressed in the next years. As a proof-of-principle study, we discuss the above-mentioned challenges with reference to three real networks: (i MagNets, an operator-driven planned two-tier mesh network; (ii Berlin Freifunk network as a pure community-driven single-tier network; (iii Weimar Freifunk network, also a community-driven but two-tier network.
Challenges in Second-Generation Wireless Mesh Networks
Directory of Open Access Journals (Sweden)
Pescapé Antonio
2008-01-01
Full Text Available Wireless mesh networks have the potential to provide ubiquitous high-speed Internet access at low costs. The good news is that initial deployments of WiFi meshes show the feasibility of providing ubiquitous Internet connectivity. However, their performance is far below the necessary and achievable limit. Moreover, users' subscription in the existing meshes is dismal even though the technical challenges to get connectivity are low. This paper provides an overview of the current status of mesh networks' deployment, and highlights the technical, economical, and social challenges that need to be addressed in the next years. As a proof-of-principle study, we discuss the above-mentioned challenges with reference to three real networks: (i MagNets, an operator-driven planned two-tier mesh network; (ii Berlin Freifunk network as a pure community-driven single-tier network; (iii Weimar Freifunk network, also a community-driven but two-tier network.
A Study on the Efficient Mesh Generation for Finite Element Analysis of Electric Machinery
Energy Technology Data Exchange (ETDEWEB)
Kim, Jin Tae [Hangul and Computer Co.,Ltd. (Korea); Chung, Tae Kyung [Chungang University (Korea); Kim, Hyeong Seok [Soonchunhyang University (Korea)
1999-04-01
To obtain more accurate result in the finite element analysis for electric machinery, it is important to have a mesh being of good quality. This paper describes a new technique of mesh generation for the finite element method. When the list of points defining the region of analysis is given, an appropriate distribution of interior points is generated first. Secondly the points are connected to form the triangles. Finally the connectivity data are used to reposition the interior points using laplacian smoothing and mesh relaxation technique. In this paper, a mesh searching technique of Lawson which modifies the start mesh is proposed in addition to the above three steps. This algorithm is simple and produces the meshes being of good quality with high speed in comparison with the existing one. (author). 16 refs., 10 figs., 2 tabs.
Unstructured Mesh Movement and Viscous Mesh Generation for CFD-Based Design Optimization Project
National Aeronautics and Space Administration — The innovations proposed by ResearchSouth are: 1) a robust method to automatically insert high quality anisotropic prismatic (viscous boundary layer) cells into any...
Automatic Testcase Generation for Flight Software
Bushnell, David Henry; Pasareanu, Corina; Mackey, Ryan M.
2008-01-01
The TacSat3 project is applying Integrated Systems Health Management (ISHM) technologies to an Air Force spacecraft for operational evaluation in space. The experiment will demonstrate the effectiveness and cost of ISHM and vehicle systems management (VSM) technologies through onboard operation for extended periods. We present two approaches to automatic testcase generation for ISHM: 1) A blackbox approach that views the system as a blackbox, and uses a grammar-based specification of the system's inputs to automatically generate *all* inputs that satisfy the specifications (up to prespecified limits); these inputs are then used to exercise the system. 2) A whitebox approach that performs analysis and testcase generation directly on a representation of the internal behaviour of the system under test. The enabling technologies for both these approaches are model checking and symbolic execution, as implemented in the Ames' Java PathFinder (JPF) tool suite. Model checking is an automated technique for software verification. Unlike simulation and testing which check only some of the system executions and therefore may miss errors, model checking exhaustively explores all possible executions. Symbolic execution evaluates programs with symbolic rather than concrete values and represents variable values as symbolic expressions. We are applying the blackbox approach to generating input scripts for the Spacecraft Command Language (SCL) from Interface and Control Systems. SCL is an embedded interpreter for controlling spacecraft systems. TacSat3 will be using SCL as the controller for its ISHM systems. We translated the SCL grammar into a program that outputs scripts conforming to the grammars. Running JPF on this program generates all legal input scripts up to a prespecified size. Script generation can also be targeted to specific parts of the grammar of interest to the developers. These scripts are then fed to the SCL Executive. ICS's in-house coverage tools will be run to
Energy Technology Data Exchange (ETDEWEB)
Lober, R.R.; Tautges, T.J.; Vaughan, C.T.
1997-03-01
Paving is an automated mesh generation algorithm which produces all-quadrilateral elements. It can additionally generate these elements in varying sizes such that the resulting mesh adapts to a function distribution, such as an error function. While powerful, conventional paving is a very serial algorithm in its operation. Parallel paving is the extension of serial paving into parallel environments to perform the same meshing functions as conventional paving only on distributed, discretized models. This extension allows large, adaptive, parallel finite element simulations to take advantage of paving`s meshing capabilities for h-remap remeshing. A significantly modified version of the CUBIT mesh generation code has been developed to host the parallel paving algorithm and demonstrate its capabilities on both two dimensional and three dimensional surface geometries and compare the resulting parallel produced meshes to conventionally paved meshes for mesh quality and algorithm performance. Sandia`s {open_quotes}tiling{close_quotes} dynamic load balancing code has also been extended to work with the paving algorithm to retain parallel efficiency as subdomains undergo iterative mesh refinement.
Automatic tool path generation for finish machining
Energy Technology Data Exchange (ETDEWEB)
Kwok, Kwan S.; Loucks, C.S.; Driessen, B.J.
1997-03-01
A system for automatic tool path generation was developed at Sandia National Laboratories for finish machining operations. The system consists of a commercially available 5-axis milling machine controlled by Sandia developed software. This system was used to remove overspray on cast turbine blades. A laser-based, structured-light sensor, mounted on a tool holder, is used to collect 3D data points around the surface of the turbine blade. Using the digitized model of the blade, a tool path is generated which will drive a 0.375 inch diameter CBN grinding pin around the tip of the blade. A fuzzified digital filter was developed to properly eliminate false sensor readings caused by burrs, holes and overspray. The digital filter was found to successfully generate the correct tool path for a blade with intentionally scanned holes and defects. The fuzzified filter improved the computation efficiency by a factor of 25. For application to general parts, an adaptive scanning algorithm was developed and presented with simulation results. A right pyramid and an ellipsoid were scanned successfully with the adaptive algorithm.
International Nuclear Information System (INIS)
Here, a workflow for high-resolution efficient numerical modeling of bioimpedance measurements is suggested that includes 3D image segmentation, adaptive mesh generation, finite-element discretization, and the analysis of simulation results. Using the adaptive unstructured tetrahedral meshes enables to decrease significantly a number of mesh elements while keeping model accuracy. The numerical results illustrate current, potential, and sensitivity field distributions for a conventional Kubicek-like scheme of bioimpedance measurements using segmented geometric model of human torso based on Visible Human Project data. The whole body VHP man computational mesh is constructed that contains 574 thousand vertices and 3.3 million tetrahedrons.
Danilov, A. A.; Salamatova, V. Yu; Vassilevski, Yu V.
2012-12-01
Here, a workflow for high-resolution efficient numerical modeling of bioimpedance measurements is suggested that includes 3D image segmentation, adaptive mesh generation, finite-element discretization, and the analysis of simulation results. Using the adaptive unstructured tetrahedral meshes enables to decrease significantly a number of mesh elements while keeping model accuracy. The numerical results illustrate current, potential, and sensitivity field distributions for a conventional Kubicek-like scheme of bioimpedance measurements using segmented geometric model of human torso based on Visible Human Project data. The whole body VHP man computational mesh is constructed that contains 574 thousand vertices and 3.3 million tetrahedrons.
International Nuclear Information System (INIS)
Fetal dosimetry studies require the development of accurate numerical 3D models of the pregnant woman and the fetus. This paper proposes a 3D articulated fetal growth model covering the main phases of pregnancy and a pregnant woman model combining the utero-fetal structures and a deformable non-pregnant woman body envelope. The structures of interest were automatically or semi-automatically (depending on the stage of pregnancy) segmented from a database of images and surface meshes were generated. By interpolating linearly between fetal structures, each one can be generated at any age and in any position. A method is also described to insert the utero-fetal structures in the maternal body. A validation of the fetal models is proposed, comparing a set of biometric measurements to medical reference charts. The usability of the pregnant woman model in dosimetry studies is also investigated, with respect to the influence of the abdominal fat layer. (paper)
FLUOMEG: a planar finite difference mesh generator for fluid flow problems with parallel boundaries
International Nuclear Information System (INIS)
A two- or three-dimensional finite difference mesh generator capable of discretizing subrectangular flow regions (planar coordinates) with arbitrarily shaped bottom contours (vertical dimension) was developed. This economical, interactive computer code, written in FORTRAN IV and employing DISSPLA software together with graphics terminal, generates first a planar rectangular grid of variable element density according to the geometry and local kinematic flow patterns of a given fluid flow problem. Then subrectangular areas are deleted to produce canals, tributaries, bays, and the like. For three-dimensional problems, arbitrary bathymetric profiles (river beds, channel cross section, ocean shoreline profiles, etc.) are approximated with grid lines forming steps of variable spacing. Furthermore, the code works as a preprocessor numbering the discrete elements and the nodal points. Prescribed values for the principal variables can be automatically assigned to solid as well as kinematic boundaries. Cabinet drawings aid in visualizing the complete flow domain. Input data requirements are necessary only to specify the spacing between grid lines, determine land regions that have to be excluded, and to identify boundary nodes. 15 figures, 2 tables
A multilevel adaptive mesh generation scheme using Kd-trees
Directory of Open Access Journals (Sweden)
Alfonso Limon
2009-04-01
Full Text Available We introduce a mesh refinement strategy for PDE based simulations that benefits from a multilevel decomposition. Using Harten's MRA in terms of Schroder-Pander linear multiresolution analysis [20], we are able to bound discontinuities in $mathbb{R}$. This MRA is extended to $mathbb{R}^n$ in terms of n-orthogonal linear transforms and utilized to identify cells that contain a codimension-one discontinuity. These refinement cells become leaf nodes in a balanced Kd-tree such that a local dyadic MRA is produced in $mathbb{R}^n$, while maintaining a minimal computational footprint. The nodes in the tree form an adaptive mesh whose density increases in the vicinity of a discontinuity.
Automatic Assignment of Non-Leaf MeSH Terms to Biomedical Articles.
Kavuluru, Ramakanth; Rios, Anthony
2015-01-01
Assigning labels from a hierarchical vocabulary is a well known special case of multi-label classification, often modeled to maximize micro F1-score. However, building accurate binary classifiers for poorly performing labels in the hierarchy can improve both micro and macro F1-scores. In this paper, we propose and evaluate classification strategies involving descendant node instances to build better binary classifiers for non-leaf labels with the use-case of assigning Medical Subject Headings (MeSH) to biomedical articles. Librarians at the National Library of Medicine tag each biomedical article to be indexed by their PubMed information system with terms from the MeSH terminology, a biomedical conceptual hierarchy with over 27,000 terms. Human indexers look at each article's full text to assign a set of most suitable MeSH terms for indexing it. Several recent automated attempts focused on using the article title and abstract text to identify MeSH terms for the corresponding article. Despite these attempts, it is observed that assigning MeSH terms corresponding to certain non-leaf nodes of the MeSH hierarchy is particularly challenging. Non-leaf nodes are very important as they constitute one third of the total number of MeSH terms. Here, we demonstrate the effectiveness of exploiting training examples of descendant terms of non-leaf nodes in improving the performance of conventional classifiers for the corresponding non-leaf MeSH terms. Specifically, we focus on reducing the false positives (FPs) caused due to descendant instances in traditional classifiers. Our methods are able to achieve a relative improvement of 7.5% in macro-F1 score while also increasing the micro-F1 score by 1.6% for a set of 500 non-leaf terms in the MeSH hierarchy. These results strongly indicate the critical role of incorporating hierarchical information in MeSH term prediction. To our knowledge, our effort is the first to demonstrate the role of hierarchical information in improving
Generating IDS Attack Pattern Automatically Based on Attack Tree
Institute of Scientific and Technical Information of China (English)
向尕; 曹元大
2003-01-01
Generating attack pattern automatically based on attack tree is studied. The extending definition of attack tree is proposed. And the algorithm of generating attack tree is presented. The method of generating attack pattern automatically based on attack tree is shown, which is tested by concrete attack instances. The results show that the algorithm is effective and efficient. In doing so, the efficiency of generating attack pattern is improved and the attack trees can be reused.
Adaptive mesh generation for non-steady state heat transport problems
International Nuclear Information System (INIS)
Full text: The paper deals with the problem of mesh generation for the two-dimensional finite element modeling. The general objective of the work is development of the mesh adaptation method and its application to non-steady state heat transport processes. The main feature of the method is generation of new triangular or quadrilateral mesh at each iteration of the adaptation procedure. This generation is performed on the basis of information obtained from the previous iteration. The adaptation is based on the evaluation of the solution curvature, which is approximated using second spatial derivatives. Discrete Hessian of the solution is applied to generate the relevant discrete metric, which is next interpolated in the whole domain. The metric is defined by three parameters: stretching of elements in two orthogonal directions and the angle of the directions with respect to the coordinate system. Thus, the mesh can be refined or stretched in the selected parts of the domain and in a selected direction. The general idea of the developed adaptation method applied to steady state problems is described. Application of the method to non-steady state heat transport processes is described in the present paper. Mesh adaptation in non-steady state processes presents several difficulties, among which decision when re-meshing should be done and transport of information from the old mesh to the new mesh are the most important. An example of application of the mesh adaptation method to the processes, which are characterized by fast changes of heat transfer coefficient in the third kind boundary conditions and by strong inhomogeneity of heat transport, is described. Refs. 1 (author)
Automatic generation of a view to geographical database
Dunkars, Mats
2001-01-01
This thesis concerns object oriented modelling and automatic generalisation of geographic information. The focus however is not on traditional paper maps, but on screen maps that are automatically generated from a geographical database. Object oriented modelling is used to design screen maps that are equipped with methods that automatically extracts information from a geographical database, generalises the information and displays it on a screen. The thesis consists of three parts: a theoreti...
Automatic program generation: future of software engineering
Energy Technology Data Exchange (ETDEWEB)
Robinson, J.H.
1979-01-01
At this moment software development is still more of an art than an engineering discipline. Each piece of software is lovingly engineered, nurtured, and presented to the world as a tribute to the writer's skill. When will this change. When will the craftsmanship be removed and the programs be turned out like so many automobiles from an assembly line. Sooner or later it will happen: economic necessities will demand it. With the advent of cheap microcomputers and ever more powerful supercomputers doubling capacity, much more software must be produced. The choices are to double the number of programers, double the efficiency of each programer, or find a way to produce the needed software automatically. Producing software automatically is the only logical choice. How will automatic programing come about. Some of the preliminary actions which need to be done and are being done are to encourage programer plagiarism of existing software through public library mechanisms, produce well understood packages such as compiler automatically, develop languages capable of producing software as output, and learn enough about the whole process of programing to be able to automate it. Clearly, the emphasis must not be on efficiency or size, since ever larger and faster hardware is coming.
ZONE: a finite element mesh generator. [In FORTRAN IV for CDC 7600
Energy Technology Data Exchange (ETDEWEB)
Burger, M. J.
1976-05-01
The ZONE computer program is a finite-element mesh generator which produces the nodes and element description of any two-dimensional geometry. The geometry is subdivided into a mesh of quadrilateral and triangular zones arranged sequentially in an ordered march through the geometry. The order of march can be chosen so that the minimum bandwidth is obtained. The node points are defined in terms of the x and y coordinates in a global rectangular coordinate system. The zones generated are quadrilaterals or triangles defined by four node points in a counterclockwise sequence. Node points defining the outside boundary are generated to describe pressure boundary conditions. The mesh that is generated can be used as input to any two-dimensional as well as any axisymmetrical structure program. The output from ZONE is essentially the input file to NAOS, HONDO, and other axisymmetric finite element programs. 14 figures. (RWR)
Mobility Models for Next Generation Wireless Networks Ad Hoc, Vehicular and Mesh Networks
Santi, Paolo
2012-01-01
Mobility Models for Next Generation Wireless Networks: Ad Hoc, Vehicular and Mesh Networks provides the reader with an overview of mobility modelling, encompassing both theoretical and practical aspects related to the challenging mobility modelling task. It also: Provides up-to-date coverage of mobility models for next generation wireless networksOffers an in-depth discussion of the most representative mobility models for major next generation wireless network application scenarios, including WLAN/mesh networks, vehicular networks, wireless sensor networks, and
Automatically Generating Game Tactics through Evolutionary Learning
Ponsen, Marc; Munoz-Avila, Hector; Spronck, Pieter; Aha, David W.
2006-01-01
The decision-making process of computer-controlled opponents in video games is called game AI. Adaptive game AI can improve the entertainment value of games by allowing computer-controlled opponents to ix weaknesses automatically in the game AI and to respond to changes in human-player tactics. Dynamic scripting is a reinforcement learning approach to adaptive game AI that learns, during gameplay, which game tactics an opponent should select to play effectively. In previous work, the tactics ...
Automatic Structure-Based Code Generation from Coloured Petri Nets
DEFF Research Database (Denmark)
Kristensen, Lars Michael; Westergaard, Michael
2010-01-01
Automatic code generation based on Coloured Petri Net (CPN) models is challenging because CPNs allow for the construction of abstract models that intermix control flow and data processing, making translation into conventional programming constructs difficult. We introduce Process-Partitioned CPNs...... viability of our approach is demonstrated by applying it to automatically generate an Erlang implementation of the Dynamic MANET On-demand (DYMO) routing protocol specified by the Internet Engineering Task Force (IETF)....
Sharifi, Hamid; Larouche, Daniel
2015-09-01
The quality of cast metal products depends on the capacity of the semi-solid metal to sustain the stresses generated during the casting. Predicting the evolution of these stresses with accuracy in the solidification interval should be highly helpful to avoid the formation of defects like hot tearing. This task is however very difficult because of the heterogeneous nature of the material. In this paper, we propose to evaluate the mechanical behaviour of a metal during solidification using a mesh generation technique of the heterogeneous semi-solid material for a finite element analysis at the microscopic level. This task is done on a two-dimensional (2D) domain in which the granular structure of the solid phase is generated surrounded by an intergranular and interdendritc liquid phase. Some basic solid grains are first constructed and projected in the 2D domain with random orientations and scale factors. Depending on their orientation, the basic grains are combined to produce larger grains or separated by a liquid film. Different basic grain shapes can produce different granular structures of the mushy zone. As a result, using this automatic grain generation procedure, we can investigate the effect of grain shapes and sizes on the thermo-mechanical behaviour of the semi-solid material. The granular models are automatically converted to the finite element meshes. The solid grains and the liquid phase are meshed properly using quadrilateral elements. This method has been used to simulate the microstructure of a binary aluminium-copper alloy (Al-5.8 wt% Cu) when the fraction solid is 0.92. Using the finite element method and the Mie-Grüneisen equation of state for the liquid phase, the transient mechanical behaviour of the mushy zone under tensile loading has been investigated. The stress distribution and the bridges, which are formed during the tensile loading, have been detected.
有限元网格剖分与网格质量判定指标%Finite Element Mesh Generation and Decision Criteria of Mesh Quality
Institute of Scientific and Technical Information of China (English)
李海峰; 吴冀川; 刘建波; 梁宇兵
2012-01-01
讨论了网格剖分中的一些常见问题,阐述了网格剖分中应遵循的要求,介绍了近十多年来网格剖分方法的研究进展,回顾了网格剖分的各种算法,并比较了各种算法的优缺点。基于工程计算需求,提出了网格质量要求及判定指标,探讨了网格质量优化问题。同时,介绍了当前广泛使用的网格剖分前处理商业软件及其应用状况,并结合工作实际,给出了复杂模型网格剖分的具体实例。最后展望了网格剖分的发展趋势。%Some general problems in mesh generation were discussed,the demands of mesh generation were expounded,the mesh generation methods were introduced,the mesh generation algorithms in last ten years were retrospected and their advantages and disadvantages were compared.Based on the requirements of practical engineering calculation,the authors brought up the mesh quality demands and decision index,explored the mesh quality optimization,introduced the preprocessors and their applications of the commercial softwares,then gave out several practical examples of the mesh generation.At last,the trends of mesh generation were also presented.
Qiu-Yu Lu; Wei Hu; Le Zheng; Yong Min; Miao Li; Xiao-Ping Li; Wei-Chun Ge; Zhi-Ming Wang
2012-01-01
Automatic Generation Control (AGC) and Automatic Voltage Control (AVC) are key approaches to frequency and voltage regulation in power systems. However, based on the assumption of decoupling of active and reactive power control, the existing AGC and AVC systems work independently without any coordination. In this paper, a concept and method of hybrid control is introduced to set up an Integrated Coordinated Optimization Control (ICOC) system for AGC and AVC. Concerning the diversity of contro...
6th International Meshing Roundtable '97
Energy Technology Data Exchange (ETDEWEB)
White, D.
1997-09-01
The goal of the 6th International Meshing Roundtable is to bring together researchers and developers from industry, academia, and government labs in a stimulating, open environment for the exchange of technical information related to the meshing process. In the pas~ the Roundtable has enjoyed significant participation born each of these groups from a wide variety of countries. The Roundtable will consist of technical presentations from contributed papers and abstracts, two invited speakers, and two invited panels of experts discussing topics related to the development and use of automatic mesh generation tools. In addition, this year we will feature a "Bring Your Best Mesh" competition and poster session to encourage discussion and participation from a wide variety of mesh generation tool users. The schedule and evening social events are designed to provide numerous opportunities for informal dialog. A proceedings will be published by Sandia National Laboratories and distributed at the Roundtable. In addition, papers of exceptionally high quaIity will be submitted to a special issue of the International Journal of Computational Geometry and Applications. Papers and one page abstracts were sought that present original results on the meshing process. Potential topics include but are got limited to: Unstructured triangular and tetrahedral mesh generation Unstructured quadrilateral and hexahedral mesh generation Automated blocking and structured mesh generation Mixed element meshing Surface mesh generation Geometry decomposition and clean-up techniques Geometry modification techniques related to meshing Adaptive mesh refinement and mesh quality control Mesh visualization Special purpose meshing algorithms for particular applications Theoretical or novel ideas with practical potential Technical presentations from industrial researchers.
Automatic Test Case Generation of C Program Using CFG
Directory of Open Access Journals (Sweden)
Sangeeta Tanwer
2010-07-01
Full Text Available Software quality and assurance in a software company is the only way to gain the customer confidence by removing all possible errors. It can be done by automatic test case generation. Taking popularly C programs as tests object, this paper explores how to create CFG of a C program and generate automatic Test Cases. It explores the feasibility and nonfeasibility of path basis upon no. of iteration. First C is code converted to instrumented code. Then test cases are generated by using Symbolic Testing and random Testing. System is developed by using C#.net in Visual Studio 2008. In addition some future research directions are also explored.
INGEN, 2-D, 3-D Mesh Generator for Finite Elements Program
International Nuclear Information System (INIS)
1 - Description of problem or function: INGEN is a general-purpose mesh generator for use in conjunction with two- and three-dimensional finite element programs. The basic components of INGEN are surface and three-dimensional region generators that use linear-blending interpolation formulae. These generators are based on an i, j, k index scheme, which is used to number nodal points, construct elements, and develop displacement and traction boundary conditions. 2 - Method of solution: The user of INGEN develops a mesh grading by first generating the boundary edges of the mesh with the desired spacing of nodal points using the line and circular-arc generators and then using surface and volume (three-dimensional region) generators, both of which preserve this spacing. The surface nodal-point generator preserves this spacing by using the nodal points as they are distributed along the boundary edges as the criteria for spacing the surface nodal points. Similarly, the volume nodal-point generator calculates the interior nodal points, using the surface nodal points as the criteria for spacing the interior nodal points. Both the surface and volume generators use linear-blending interpolation equations for calculating nodal point coordinates. 3 - Restrictions on the complexity of the problem: The origin cannot be used as the coordinates of a nodal point because the zero coordinates are a test used for nonexistent nodal points
Automatic Generation of Video Narratives from Shared UGC
Zsombori, V.; Frantzis, M.; Guimarães, R.L.; Ursu, M.; Cesar Garcia, P.S.; Kegel, I.; Craigie, R.; Bulterman, D.C.A.
2011-01-01
This paper introduces an evaluated approach to the automatic generation of video narratives from user generated content gathered in a shared repository. In the context of social events, end-users record video material with their personal cameras and upload the content to a common repository. Video n
Automatic generation of matter-of-opinion video documentaries
Bocconi, S.; Nack, F.-M.; Hardman, L.
2008-01-01
In this paper we describe a model for automatically generating video documentaries. This allows viewers to specify the subject and the point of view of the documentary to be generated. The domain is matter-of-opinion documentaries based on interviews. The model combines rhetorical presentation patte
Automatic generation of a neural network architecture using evolutionary computation
Vonk, E.; Jain, L.C.; Veelenturf, L.P.J.; Johnson, R.
1995-01-01
This paper reports the application of evolutionary computation in the automatic generation of a neural network architecture. It is a usual practice to use trial and error to find a suitable neural network architecture. This is not only time consuming but may not generate an optimal solution for a gi
Vox populi: a tool for automatically generating video documentaries
Bocconi, S.; Nack, Frank; Hardman, Hazel Lynda
2005-01-01
Vox Populi is a system that automatically generates video documentaries. Our application domain is video interviews about controversial topics. Via a Web interface the user selects one of the possible topics and a point of view she would like the generated sequence to present, and the engine selects and assembles video material from the repository to satisfy the user request.
DECROOS Koenraad; OHMS Carsten; Petrov, Roumen; Seefeldt, Marc; Verhaeghe, Frederik; Kestens, Leo
2013-01-01
A new method has been designed to automatically adapt the geometry of the fusion zone of a weld according to the temperature calculations when the thermal welding heat source parameters are known. In the material definition in a Finite Element code for welding stress calculations, the fusion zone material has different properties than the base material since, among others, the temperature at which the material is stress free is the melting temperature instead of room temperature. In this work...
Automated Tetrahedral Mesh Generation for CFD Analysis of Aircraft in Conceptual Design
Ordaz, Irian; Li, Wu; Campbell, Richard L.
2014-01-01
The paper introduces an automation process of generating a tetrahedral mesh for computational fluid dynamics (CFD) analysis of aircraft configurations in early conceptual design. The method was developed for CFD-based sonic boom analysis of supersonic configurations, but can be applied to aerodynamic analysis of aircraft configurations in any flight regime.
Transonic Airfoil Flow Simulation. Part I: Mesh Generation and Inviscid Method
Directory of Open Access Journals (Sweden)
Vladimir CARDOS
2010-06-01
Full Text Available A calculation method for the subsonic and transonic viscous flow over airfoil using thedisplacement surface concept is described. Part I presents a mesh generation method forcomputational grid and a finite volume method for the time-dependent Euler equations. The inviscidsolution is used for the inviscid-viscous coupling procedure presented in the Part II.
Mapping method for generating three-dimensional meshes: past and present
International Nuclear Information System (INIS)
Two transformations are derived in this paper. One is a mapping of a unit square onto a surve and the other is a mapping of a unit cube onto a three-dimensional region. Two meshing computer programs are then discussed that use these mappings. The first is INGEN, which has been used to calculate three-dimensional meshes for approximately 15 years. This meshing program uses an index scheme to number boundaries, surfaces, and regions. With such an index scheme, it is possible to control nodal points, elements, and boundary conditions. The second is ESCHER, a meshing program now being developed. Two primary considerations governing development of ESCHER are that meshes graded using quadrilaterals are required and that edge-line geometry defined by Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) systems will be a major source of geometry definition. This program separates the processes of nodal-point connectivity generation, computation of nodal-point mapping space coordinates, and mapping of nodal points into model space
Parallel octree-based hexahedral mesh generation for eulerian to lagrangian conversion.
Energy Technology Data Exchange (ETDEWEB)
Staten, Matthew L.; Owen, Steven James
2010-09-01
Computational simulation must often be performed on domains where materials are represented as scalar quantities or volume fractions at cell centers of an octree-based grid. Common examples include bio-medical, geotechnical or shock physics calculations where interface boundaries are represented only as discrete statistical approximations. In this work, we introduce new methods for generating Lagrangian computational meshes from Eulerian-based data. We focus specifically on shock physics problems that are relevant to ASC codes such as CTH and Alegra. New procedures for generating all-hexahedral finite element meshes from volume fraction data are introduced. A new primal-contouring approach is introduced for defining a geometric domain. New methods for refinement, node smoothing, resolving non-manifold conditions and defining geometry are also introduced as well as an extension of the algorithm to handle tetrahedral meshes. We also describe new scalable MPI-based implementations of these procedures. We describe a new software module, Sculptor, which has been developed for use as an embedded component of CTH. We also describe its interface and its use within the mesh generation code, CUBIT. Several examples are shown to illustrate the capabilities of Sculptor.
A unified approach for a posteriori high-order curved mesh generation using solid mechanics
Poya, Roman; Sevilla, Ruben; Gil, Antonio J.
2016-06-01
The paper presents a unified approach for the a posteriori generation of arbitrary high-order curvilinear meshes via a solid mechanics analogy. The approach encompasses a variety of methodologies, ranging from the popular incremental linear elastic approach to very sophisticated non-linear elasticity. In addition, an intermediate consistent incrementally linearised approach is also presented and applied for the first time in this context. Utilising a consistent derivation from energy principles, a theoretical comparison of the various approaches is presented which enables a detailed discussion regarding the material characterisation (calibration) employed for the different solid mechanics formulations. Five independent quality measures are proposed and their relations with existing quality indicators, used in the context of a posteriori mesh generation, are discussed. Finally, a comprehensive range of numerical examples, both in two and three dimensions, including challenging geometries of interest to the solids, fluids and electromagnetics communities, are shown in order to illustrate and thoroughly compare the performance of the different methodologies. This comparison considers the influence of material parameters and number of load increments on the quality of the generated high-order mesh, overall computational cost and, crucially, the approximation properties of the resulting mesh when considering an isoparametric finite element formulation.
Kainmueller, Dagmar
2014-01-01
? Segmentation of anatomical structures in medical image data is an essential task in clinical practice. Dagmar Kainmueller introduces methods for accurate fully automatic segmentation of anatomical structures in 3D medical image data. The author's core methodological contribution is a novel deformation model that overcomes limitations of state-of-the-art Deformable Surface approaches, hence allowing for accurate segmentation of tip- and ridge-shaped features of anatomical structures. As for practical contributions, she proposes application-specific segmentation pipelines for a range of anatom
International Nuclear Information System (INIS)
A set of computer codes for triangular six-node finite element mesh generation in fast reactor fuel assemblies (or their parts) is described as are directions for input data preparation and operator's actions. The generated meshes are utilized for velocity and temperature calculations. (author)
Hazer, D.; Schmidt, E.; Unterhinninghofen, R.; Richter, G. M.; Dillmann, R.
2009-08-01
Abnormal hemodynamics and biomechanics of blood flow and vessel wall conditions in the arteries may result in severe cardiovascular diseases. Cardiovascular diseases result from complex flow pattern and fatigue of the vessel wall and are prevalent causes leading to high mortality each year. Computational Fluid Dynamics (CFD), Computational Structure Mechanics (CSM) and Fluid Structure Interaction (FSI) have become efficient tools in modeling the individual hemodynamics and biomechanics as well as their interaction in the human arteries. The computations allow non-invasively simulating patient-specific physical parameters of the blood flow and the vessel wall needed for an efficient minimally invasive treatment. The numerical simulations are based on the Finite Element Method (FEM) and require exact and individual mesh models to be provided. In the present study, we developed a numerical tool to automatically generate complex patient-specific Finite Element (FE) mesh models from image-based geometries of healthy and diseased vessels. The mesh generation is optimized based on the integration of mesh control functions for curvature, boundary layers and mesh distribution inside the computational domain. The needed mesh parameters are acquired from a computational grid analysis which ensures mesh-independent and stable simulations. Further, the generated models include appropriate FE sets necessary for the definition of individual boundary conditions, required to solve the system of nonlinear partial differential equations governed by the fluid and solid domains. Based on the results, we have performed computational blood flow and vessel wall simulations in patient-specific aortic models providing a physical insight into the pathological vessel parameters. Automatic mesh generation with individual awareness in terms of geometry and conditions is a prerequisite for performing fast, accurate and realistic FEM-based computations of hemodynamics and biomechanics in the
MEMOPS: data modelling and automatic code generation.
Fogh, Rasmus H; Boucher, Wayne; Ionides, John M C; Vranken, Wim F; Stevens, Tim J; Laue, Ernest D
2010-01-01
In recent years the amount of biological data has exploded to the point where much useful information can only be extracted by complex computational analyses. Such analyses are greatly facilitated by metadata standards, both in terms of the ability to compare data originating from different sources, and in terms of exchanging data in standard forms, e.g. when running processes on a distributed computing infrastructure. However, standards thrive on stability whereas science tends to constantly move, with new methods being developed and old ones modified. Therefore maintaining both metadata standards, and all the code that is required to make them useful, is a non-trivial problem. Memops is a framework that uses an abstract definition of the metadata (described in UML) to generate internal data structures and subroutine libraries for data access (application programming interfaces--APIs--currently in Python, C and Java) and data storage (in XML files or databases). For the individual project these libraries obviate the need for writing code for input parsing, validity checking or output. Memops also ensures that the code is always internally consistent, massively reducing the need for code reorganisation. Across a scientific domain a Memops-supported data model makes it easier to support complex standards that can capture all the data produced in a scientific area, share them among all programs in a complex software pipeline, and carry them forward to deposition in an archive. The principles behind the Memops generation code will be presented, along with example applications in Nuclear Magnetic Resonance (NMR) spectroscopy and structural biology. PMID:20375445
Bucki, Marek; Payan, Yohan; 10.1016/j.media.2010.02.003
2010-01-01
Finite Element mesh generation remains an important issue for patient specific biomechanical modeling. While some techniques make automatic mesh generation possible, in most cases, manual mesh generation is preferred for better control over the sub-domain representation, element type, layout and refinement that it provides. Yet, this option is time consuming and not suited for intraoperative situations where model generation and computation time is critical. To overcome this problem we propose a fast and automatic mesh generation technique based on the elastic registration of a generic mesh to the specific target organ in conjunction with element regularity and quality correction. This Mesh-Match-and-Repair (MMRep) approach combines control over the mesh structure along with fast and robust meshing capabilities, even in situations where only partial organ geometry is available. The technique was successfully tested on a database of 5 pre-operatively acquired complete femora CT scans, 5 femoral heads partially...
ZONE - a finite element mesh generator. [2-D, for CDC 7600
Energy Technology Data Exchange (ETDEWEB)
Burger, M.J.
1980-03-12
The ZONE computer program is a finite element mesh generator that produces the nodes and element description of any two-dimensional geometry. The geometry is subdivided into a mesh of quadrilateral and triangular zones arranged sequentially in an ordered march through the geometry. The order of march can be chosen so that the minimum bandwidth is obtained. The node points are defined in terms of the x and y coordinates in a global rectangular coordinate system. The zones generated are quadrilaterals or triangles defined by four node points in a counterclockwise sequence. Node points defining the outside boundary are generated for slide lines and to describe pressure boundary conditions. The mesh that is generated can be used as input to any two dimensional as well as any axisymmetrical structure program. The following points are taken up: program concept and characteristics; regions; layers; meridians (offset, circular arc, ellipse); rays; common characterstics - rays and meridians, ZONE input description; output files; examples; and program availability. Also generated is the input to the program PLOT. 15 figures. (RWR)
Automatic Generation of Tests from Domain and Multimedia Ontologies
Papasalouros, Andreas; Kotis, Konstantinos; Kanaris, Konstantinos
2011-01-01
The aim of this article is to present an approach for generating tests in an automatic way. Although other methods have been already reported in the literature, the proposed approach is based on ontologies, representing both domain and multimedia knowledge. The article also reports on a prototype implementation of this approach, which…
Mppsocgen: A framework for automatic generation of mppsoc architecture
Kallel, Emna; Baklouti, Mouna; Abid, Mohamed
2012-01-01
Automatic code generation is a standard method in software engineering since it improves the code consistency and reduces the overall development time. In this context, this paper presents a design flow for automatic VHDL code generation of mppSoC (massively parallel processing System-on-Chip) configuration. Indeed, depending on the application requirements, a framework of Netbeans Platform Software Tool named MppSoCGEN was developed in order to accelerate the design process of complex mppSoC. Starting from an architecture parameters design, VHDL code will be automatically generated using parsing method. Configuration rules are proposed to have a correct and valid VHDL syntax configuration. Finally, an automatic generation of Processor Elements and network topologies models of mppSoC architecture will be done for Stratix II device family. Our framework improves its flexibility on Netbeans 5.5 version and centrino duo Core 2GHz with 22 Kbytes and 3 seconds average runtime. Experimental results for reduction al...
A quick scan on possibilities for automatic metadata generation
Benneker, Frank
2006-01-01
The Quick Scan is a report on research into useable solutions for automatic generation of metadata or parts of metadata. The aim of this study is to explore possibilities for facilitating the process of attaching metadata to learning objects. This document is aimed at developers of digital learning
Algorithm for automatic generating motion trajectories of plant maintenance robot
International Nuclear Information System (INIS)
The algorithm for automatic generating motion trajectories of robot manipulator is proposed as a new method to operate plant maintenance robots. This algorithm consists of two procedures, motion trajectories of the end effecter and the posture of robot manipulator. Motion trajectories of the end effecter are generated by using a concept of repulsive force vector field. The motion trajectories model which consists of many virtual springs and mass points are changed their form using the repulsive force from obstacles. Then, a posture of robot manipulator is also automatically generated with the same concept. By using this algorithm, an experiment of generating motion with the 7 degrees of freedom (DOF) manipulator was carried out. As a result, it was confirmed that the proposed method realizes obstacle avoidance during task motion. We are planning to apply this system to nuclear power plants. This system can realize shortening of preparation and operation periods for maintenance work in the nuclear reactor. (author)
Video2GIF: Automatic Generation of Animated GIFs from Video
Gygli, Michael; Song, Yale; Cao, Liangliang
2016-01-01
We introduce the novel problem of automatically generating animated GIFs from video. GIFs are short looping video with no sound, and a perfect combination between image and video that really capture our attention. GIFs tell a story, express emotion, turn events into humorous moments, and are the new wave of photojournalism. We pose the question: Can we automate the entirely manual and elaborate process of GIF creation by leveraging the plethora of user generated GIF content? We propose a Robu...
AN APPROACH TO GENERATE TEST CASES AUTOMATICALLY USING GENETIC ALGORITHM
Deepika Sharma*, Dr. Sanjay Tyagi
2016-01-01
Software testing is a very crucial part among all phases of software life cycle model in software engineering, which leads to better software quality and reliability. The main issue of software testing is the incompleteness of testing due to the vast amount of possible test cases which increase the effort and cost of the software. So generating adequate test cases will help to reduce the effort and cost of the software. The purpose of this research paper is to automatically generate test case...
Extending a CAD-Based Cartesian Mesh Generator for the Lattice Boltzmann Method
Energy Technology Data Exchange (ETDEWEB)
Cantrell, J Nathan [ORNL; Inclan, Eric J [ORNL; Joshi, Abhijit S [ORNL; Popov, Emilian L [ORNL; Jain, Prashant K [ORNL
2012-01-01
This paper describes the development of a custom preprocessor for the PaRAllel Thermal Hydraulics simulations using Advanced Mesoscopic methods (PRATHAM) code based on an open-source mesh generator, CartGen [1]. PRATHAM is a three-dimensional (3D) lattice Boltzmann method (LBM) based parallel flow simulation software currently under development at the Oak Ridge National Laboratory. The LBM algorithm in PRATHAM requires a uniform, coordinate system-aligned, non-body-fitted structured mesh for its computational domain. CartGen [1], which is a GNU-licensed open source code, already comes with some of the above needed functionalities. However, it needs to be further extended to fully support the LBM specific preprocessing requirements. Therefore, CartGen is being modified to (i) be compiler independent while converting a neutral-format STL (Stereolithography) CAD geometry to a uniform structured Cartesian mesh, (ii) provide a mechanism for PRATHAM to import the mesh and identify the fluid/solid domains, and (iii) provide a mechanism to visually identify and tag the domain boundaries on which to apply different boundary conditions.
Algebraic mesh generation for large scale viscous-compressible aerodynamic simulation
International Nuclear Information System (INIS)
Viscous-compressible aerodynamic simulation is the numerical solution of the compressible Navier-Stokes equations and associated boundary conditions. Boundary-fitted coordinate systems are well suited for the application of finite difference techniques to the Navier-Stokes equations. An algebraic approach to boundary-fitted coordinate systems is one where an explicit functional relation describes a mesh on which a solution is obtained. This approach has the advantage of rapid-precise mesh control. The basic mathematical structure of three algebraic mesh generation techniques is described. They are transfinite interpolation, the multi-surface method, and the two-boundary technique. The Navier-Stokes equations are transformed to a computational coordinate system where boundary-fitted coordinates can be applied. Large-scale computation implies that there is a large number of mesh points in the coordinate system. Computation of viscous compressible flow using boundary-fitted coordinate systems and the application of this computational philosophy on a vector computer are presented
Mauro Massayoshi Sakamoto; José Roberto Cardoso; José Marcio Machado
2008-01-01
In this work, a software package based on the Delaunay´s algorithm is described. The main feature of this package is the capability in applying discretization in geometric domains of teeth taking into account their complex inner structures and the materials with different hardness. Usually, the mesh generators reported in literature treat molars and other teeth by using simplified geometric models, or even considering the teeth as homogeneous structures.
Directory of Open Access Journals (Sweden)
Mauro Massayoshi Sakamoto
2008-01-01
Full Text Available In this work, a software package based on the Delaunay´s algorithm is described. The main feature of this package is the capability in applying discretization in geometric domains of teeth taking into account their complex inner structures and the materials with different hardness. Usually, the mesh generators reported in literature treat molars and other teeth by using simplified geometric models, or even considering the teeth as homogeneous structures.
International Nuclear Information System (INIS)
AUTOCASK (AUTOmatic Generation of 3-D CASK models) is a microcomputer-based system of computer programs and databases developed at the Lawrence Livermore National Laboratory (LLNL) for the structural analysis of shipping casks for radioactive material. Model specification is performed on the microcomputer, and the analyses are performed on an engineering workstation or mainframe computer. AUTOCASK is based on 80386/80486 compatible microcomputers. The system is composed of a series of menus, input programs, display programs, a mesh generation program, and archive programs. All data is entered through fill-in-the-blank input screens that contain descriptive data requests
Lorié, William A.
2013-01-01
A reverse engineering approach to automatic item generation (AIG) was applied to a figure-based publicly released test item from the Organisation for Economic Cooperation and Development (OECD) Programme for International Student Assessment (PISA) mathematical literacy cognitive instrument as part of a proof of concept. The author created an item…
Automatic control system generation for robot design validation
Bacon, James A. (Inventor); English, James D. (Inventor)
2012-01-01
The specification and drawings present a new method, system and software product for and apparatus for generating a robotic validation system for a robot design. The robotic validation system for the robot design of a robotic system is automatically generated by converting a robot design into a generic robotic description using a predetermined format, then generating a control system from the generic robotic description and finally updating robot design parameters of the robotic system with an analysis tool using both the generic robot description and the control system.
Automatic generation of neural network architecture using evolutionary computation
Vonk, E
1997-01-01
This book describes the application of evolutionary computation in the automatic generation of a neural network architecture. The architecture has a significant influence on the performance of the neural network. It is the usual practice to use trial and error to find a suitable neural network architecture for a given problem. The process of trial and error is not only time-consuming but may not generate an optimal network. The use of evolutionary computation is a step towards automation in neural network architecture generation.An overview of the field of evolutionary computation is presented
Automated Generation of Finite-Element Meshes for Aircraft Conceptual Design
Li, Wu; Robinson, Jay
2016-01-01
This paper presents a novel approach for automated generation of fully connected finite-element meshes for all internal structural components and skins of a given wing-body geometry model, controlled by a few conceptual-level structural layout parameters. Internal structural components include spars, ribs, frames, and bulkheads. Structural layout parameters include spar/rib locations in wing chordwise/spanwise direction and frame/bulkhead locations in longitudinal direction. A simple shell thickness optimization problem with two load conditions is used to verify versatility and robustness of the automated meshing process. The automation process is implemented in ModelCenter starting from an OpenVSP geometry and ending with a NASTRAN 200 solution. One subsonic configuration and one supersonic configuration are used for numerical verification. Two different structural layouts are constructed for each configuration and five finite-element meshes of different sizes are generated for each layout. The paper includes various comparisons of solutions of 20 thickness optimization problems, as well as discussions on how the optimal solutions are affected by the stress constraint bound and the initial guess of design variables.
Optimum siting and sizing of a large distributed generator in a mesh connected system
Energy Technology Data Exchange (ETDEWEB)
Elnashar, Mohab M.; El Shatshat, Ramadan; Salama, Magdy M.A. [Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario (Canada)
2010-06-15
This paper proposes a new approach to optimally determine the appropriate size and location of the distributed generator (DG) in a large mesh connected system. This paper presents a visual optimization approach in which the planner plays an important role in determining the optimal siting and sizing of the DG through the choice of the appropriate weight factors of the parameters included in the optimization technique according to the system deficiencies. Losses, voltage profile and short circuit level are used in the algorithm to determine the optimum sizes and locations of the DG. The short circuit level parameter is introduced to represent the protective device requirements in the selection of the size and location of the DG. The proposed technique has been tested on the IEEE 24 - bus mesh connected test system. The obtained results showed clearly that the optimal size and location can be simply determined through the proposed approach. (author)
An automatic control system for a power-generating unit
Energy Technology Data Exchange (ETDEWEB)
Itelman, U.R.; Mankin, M.N.; Mikhailova, I.V.
1979-02-05
There exists an automatic control system for a power-generating unit, which contains a load regulator for the turbine, which is connected to the output of the actuator valve servo motor together with the slide valve of the regulator measuring channel, a boiler productivity regulator and a frequency-compensation unit for controlling the input power; the output from this unit is connected to the input to the turbine load regulator and the boiler productivity regulator. In this automatic control system, the compensation unit is manufactured in the form of a frequency deviation sensor connected to the voltage transformer of the generator--it is a complex electronic and conversion component. In order to simplify this design of the compensation unit, it is manufactured as a motion sensor, which is mechanically connected to the slide valve. This connection is made through the slide box of the valve or through the valve position rod.
Automatic Generation of Thematically Focused Information Portals from Web Data
Sizov, Sergej
2005-01-01
Finding the desired information on the Web is often a hard and time-consuming task. This thesis presents the methodology of automatic generation of thematically focused portals from Web data. The key component of the proposed Web retrieval framework is the thematically focused Web crawler that is interested only in a specific, typically small, set of topics. The focused crawler uses classification methods for filtering of fetched documents and identifying most likely relevant Web source...
MadEvent: automatic event generation with MadGraph
International Nuclear Information System (INIS)
We present a new multi-channel integration method and its implementation in the multi-purpose event generator MadEvent, which is based on MadGraph. Given a process, MadGraph automatically identifies all the relevant subprocesses, generates both the amplitudes and the mappings needed for an efficient integration over the phase space, and passes them to MadEvent. As a result, a process-specific, stand-alone code is produced that allows the user to calculate cross sections and produce unweighted events in a standard output format. Several examples are given for processes that are relevant for physics studies at present and forthcoming colliders. (author)
Progressive Concept Evaluation Method for Automatically Generated Concept Variants
Directory of Open Access Journals (Sweden)
Woldemichael Dereje Engida
2014-07-01
Full Text Available Conceptual design is one of the most critical and important phases of design process with least computer support system. Conceptual design support tool (CDST is a conceptual design support system developed to automatically generate concepts for each subfunction in functional structure. The automated concept generation process results in large number of concept variants which require a thorough evaluation process to select the best design. To address this, a progressive concept evaluation technique consisting of absolute comparison, concept screening and weighted decision matrix using analytical hierarchy process (AHP is proposed to eliminate infeasible concepts at each stage. The software implementation of the proposed method is demonstrated.
Impulse Wave Generation: Comparison of Free Granular with Mesh-Packed Slides
Directory of Open Access Journals (Sweden)
Frederic M. Evers
2015-03-01
Full Text Available Slides generating impulse waves are currently generated using either block models or free granular material impacting a water body. These procedures were mainly developed to study plane impulse waves, i.e., wave generation in a rectangular channel. The current VAW, ETH Zurich, research is directed to the spatial impulse wave features, i.e., waves propagating in a wave basin. The two wave generation mechanisms mentioned above complicate this process for various reasons, including experimental handling, collection of slide material in the wave basin, poor representation of prototype conditions for the block model, and excessive temporal duration for free granular slides. Impulse waves originating from slides with free granular material and mesh-packed slides are compared in this paper. Detailed test series are presented, so that the resulting main wave features can be compared. The results highlight whether the simplified procedure involving mesh-packed slides really applies in future research, and specify advantages in terms of impulse wave experimentation.
Sarkis, C.; Silva, L.; Gandin, Ch-A.; Plapp, M.
2016-03-01
Dendritic growth is computed with automatic adaptation of an anisotropic and unstructured finite element mesh. The energy conservation equation is formulated for solid and liquid phases considering an interface balance that includes the Gibbs-Thomson effect. An equation for a diffuse interface is also developed by considering a phase field function with constant negative value in the liquid and constant positive value in the solid. Unknowns are the phase field function and a dimensionless temperature, as proposed by [1]. Linear finite element interpolation is used for both variables, and discretization stabilization techniques ensure convergence towards a correct non-oscillating solution. In order to perform quantitative computations of dendritic growth on a large domain, two additional numerical ingredients are necessary: automatic anisotropic unstructured adaptive meshing [2,[3] and parallel implementations [4], both made available with the numerical platform used (CimLib) based on C++ developments. Mesh adaptation is found to greatly reduce the number of degrees of freedom. Results of phase field simulations for dendritic solidification of a pure material in two and three dimensions are shown and compared with reference work [1]. Discussion on algorithm details and the CPU time will be outlined.
Automatic generation of executable communication specifications from parallel applications
Energy Technology Data Exchange (ETDEWEB)
Pakin, Scott [Los Alamos National Laboratory; Wu, Xing [NCSU; Mueller, Frank [NCSU
2011-01-19
Portable parallel benchmarks are widely used and highly effective for (a) the evaluation, analysis and procurement of high-performance computing (HPC) systems and (b) quantifying the potential benefits of porting applications for new hardware platforms. Yet, past techniques to synthetically parameterized hand-coded HPC benchmarks prove insufficient for today's rapidly-evolving scientific codes particularly when subject to multi-scale science modeling or when utilizing domain-specific libraries. To address these problems, this work contributes novel methods to automatically generate highly portable and customizable communication benchmarks from HPC applications. We utilize ScalaTrace, a lossless, yet scalable, parallel application tracing framework to collect selected aspects of the run-time behavior of HPC applications, including communication operations and execution time, while abstracting away the details of the computation proper. We subsequently generate benchmarks with identical run-time behavior from the collected traces. A unique feature of our approach is that we generate benchmarks in CONCEPTUAL, a domain-specific language that enables the expression of sophisticated communication patterns using a rich and easily understandable grammar yet compiles to ordinary C + MPI. Experimental results demonstrate that the generated benchmarks are able to preserve the run-time behavior - including both the communication pattern and the execution time - of the original applications. Such automated benchmark generation is particularly valuable for proprietary, export-controlled, or classified application codes: when supplied to a third party. Our auto-generated benchmarks ensure performance fidelity but without the risks associated with releasing the original code. This ability to automatically generate performance-accurate benchmarks from parallel applications is novel and without any precedence, to our knowledge.
Visual definition of procedures for automatic virtual scene generation
Lucanin, Drazen
2012-01-01
With more and more digital media, especially in the field of virtual reality where detailed and convincing scenes are much required, procedural scene generation is a big helping tool for artists. A problem is that defining scene descriptions through these procedures usually requires a knowledge in formal language grammars, programming theory and manually editing textual files using a strict syntax, making it less intuitive to use. Luckily, graphical user interfaces has made a lot of tasks on computers easier to perform and out of the belief that creating computer programs can also be one of them, visual programming languages (VPLs) have emerged. The goal in VPLs is to shift more work from the programmer to the integrated development environment (IDE), making programming an user-friendlier task. In this thesis, an approach of using a VPL for defining procedures that automatically generate virtual scenes is presented. The methods required to build a VPL are presented, including a novel method of generating read...
Automatic generation of alignments for 3D QSAR analyses.
Jewell, N E; Turner, D B; Willett, P; Sexton, G J
2001-01-01
Many 3D QSAR methods require the alignment of the molecules in a dataset, which can require a fair amount of manual effort in deciding upon a rational basis for the superposition. This paper describes the use of FBSS, a program for field-based similarity searching in chemical databases, for generating such alignments automatically. The CoMFA and CoMSIA experiments with several literature datasets show that the QSAR models resulting from the FBSS alignments are broadly comparable in predictive performance with the models resulting from manual alignments. PMID:11774998
Automatic generation of alignments for 3D QSAR analyses
Jewell, N.E.; D.B. Turner; Willett, P.; Sexton, G.J.
2001-01-01
Many 3D QSAR methods require the alignment of the molecules in a dataset, which can require a fair amount of manual effort in deciding upon a rational basis for the superposition. This paper describes the use of FBSS, a pro-ram for field-based similarity searching in chemical databases, for generating such alignments automatically. The CoMFA and CoMSIA experiments with several literature datasets show that the QSAR models resulting from the FBSS alignments are broadly comparable in predictive...
Automatic generation of application specific FPGA multicore accelerators
DEFF Research Database (Denmark)
Hindborg, Andreas Erik; Schleuniger, Pascal; Jensen, Nicklas Bo;
2014-01-01
. In this paper we propose a tool flow, which automatically generates highly optimized hardware multicore systems based on parameters. Profiling feedback is used to adjust these parameters to improve performance and lower the power consumption. For an image processing application we show that our tools are able......High performance computing systems make increasing use of hardware accelerators to improve performance and power properties. For large high-performance FPGAs to be successfully integrated in such computing systems, methods to raise the abstraction level of FPGA programming are required...
Automatic Generation of 3D Building Models with Multiple Roofs
Institute of Scientific and Technical Information of China (English)
Kenichi Sugihara; Yoshitugu Hayashi
2008-01-01
Based on building footprints (building polygons) on digital maps, we are proposing the GIS and CG integrated system that automatically generates 3D building models with multiple roofs. Most building polygons' edges meet at right angles (orthogonal polygon). The integrated system partitions orthogonal building polygons into a set of rectangles and places rectangular roofs and box-shaped building bodies on these rectangles. In order to partition an orthogonal polygon, we proposed a useful polygon expression in deciding from which vertex a dividing line is drawn. In this paper, we propose a new scheme for partitioning building polygons and show the process of creating 3D roof models.
Raut, Samarth S; Liu, Peng; Finol, Ender A
2015-07-16
In this work, we present a computationally efficient image-derived volume mesh generation approach for vasculatures that implements spatially varying patient-specific wall thickness with a novel inward extrusion of the wall surface mesh. Multi-domain vascular meshes with arbitrary numbers, locations, and patterns of both iliac bifurcations and thrombi can be obtained without the need to specify features or landmark points as input. In addition, the mesh output is coordinate-frame independent and independent of the image grid resolution with high dimensional accuracy and mesh quality, devoid of errors typically found in off-the-shelf image-based model generation workflows. The absence of deformable template models or Cartesian grid-based methods enables the present approach to be sufficiently robust to handle aneurysmatic geometries with highly irregular shapes, arterial branches nearly parallel to the image plane, and variable wall thickness. The assessment of the methodology was based on i) estimation of the surface reconstruction accuracy, ii) validation of the output mesh using an aneurysm phantom, and iii) benchmarking the volume mesh quality against other frameworks. For the phantom image dataset (pixel size 0.105 mm; slice spacing 0.7 mm; and mean wall thickness 1.401±0.120 mm), the average wall thickness in the mesh was 1.459±0.123 mm. The absolute error in average wall thickness was 0.060±0.036 mm, or about 8.6% of the largest image grid spacing (0.7 mm) and 4.36% of the actual mean wall thickness. Mesh quality metrics and the ability to reproduce regional variations of wall thickness were found superior to similar alternative frameworks. PMID:25976018
Pavarino, E.; Neves, L. A.; Machado, J. M.; de Godoy, M. F.; Y. Shiyou; Momente, J. C.; Zafalon, G. F. D.; A.R. Pinto; C. R. Valêncio
2013-01-01
The Finite Element Method is a well-known technique, being extensively applied in different areas. Studies using the Finite Element Method (FEM) are targeted to improve cardiac ablation procedures. For such simulations, the finite element meshes should consider the size and histological features of the target structures. However, it is possible to verify that some methods or tools used to generate meshes of human body structures are still limited, due to nondetailed models, nontrivial preproc...
Semi-Automatic Construction of the Chinese-English MeSH Using Web-Based Term Translation Method
Lu, Wen-Hsiang; Lin, Shih-Jui; Chan, Yi-Che; Chen, Kuan-Hsi
2005-01-01
Due to language barrier, non-English users are unable to retrieve the most updated medical information from the U.S. authoritative medical websites, such as PubMed and MedlinePlus. A few cross-language medical information retrieval (CLMIR) systems have been utilizing MeSH (Medical Subject Heading) with multilingual thesaurus to bridge the gap. Unfortunately, MeSH has yet not been translated into traditional Chinese currently.
The Geometry of r-adaptive meshes generated using Optimal Transport Methods
C. J. Budd; Russell, R. D.; Walsh, E.
2014-01-01
The principles of mesh equidistribution and alignment play a fundamental role in the design of adaptive methods, and a metric tensor M and mesh metric are useful theoretical tools for understanding a methods level of mesh alignment, or anisotropy. We consider a mesh redistribution method based on the Monge-Ampere equation, which combines equidistribution of a given scalar density function with optimal transport. It does not involve explicit use of a metric tensor M, although such a tensor mus...
Node-based parallel mesh generation and finite element solver for high speed compressible flows
International Nuclear Information System (INIS)
A node-based parallel mesh generation and finite element procedure for high speed compressible flows is presented. In general, the numerical analysis of flows with shock waves requires very fine computational grids and consumes a lot of computing time. For such large amounts of calculations, parallel computing is very effective. However, a lot of parallel techniques for CFD focus strictly on the solution of the system of equations, while the mesh generation process is not parallelized in many cases. In the present work, we attempt seamless parallel computing involving pre-processing and main-processing for compressible flows. The finite elements are generated in the local area around each node and the finite element assembly operations are carried out node-by-node. In this method, both pre-processing and main-processing are parallelized by means of the nodal identification number. Load balancing is achieved by simply allocating equal number of nodes to each processor. Furthermore, the amount of the communication among processors is minimized by reordering the nodal identification number using the parallel graph partitioning library, ParMETIS. As for the numerical scheme for compressible Euler equations, the two-step Taylor-Galerkin method is employed. In order to remove the numerical instability, artificial viscosity based on the Lapidus model is applied. The concept of an element in the usual FEM is represented by a data structure of the connectivity between a central node and associated satellite nodes. The communication among different processors is required if and only if associated satellite nodes exist in other processors. The present method is implemented on distributed memory systems such as a PC cluster and a commercial massively paralleled computer. The performance of the method is illustrated by computing of supersonic flows over a forward facing step. These examples show that crisp shock waves are effectively computed on multiple processors. The total
Directory of Open Access Journals (Sweden)
Qiu-Yu Lu
2012-09-01
Full Text Available Automatic Generation Control (AGC and Automatic Voltage Control (AVC are key approaches to frequency and voltage regulation in power systems. However, based on the assumption of decoupling of active and reactive power control, the existing AGC and AVC systems work independently without any coordination. In this paper, a concept and method of hybrid control is introduced to set up an Integrated Coordinated Optimization Control (ICOC system for AGC and AVC. Concerning the diversity of control devices and the characteristics of discrete control interaction with a continuously operating power system, the ICOC system is designed in a hierarchical structure and driven by security, quality and economic events, consequently reducing optimization complexity and realizing multi-target quasi-optimization. In addition, an innovative model of Loss Minimization Control (LMC taking into consideration active and reactive power regulation is proposed to achieve a substantial reduction in network losses and a cross iterative method for AGC and AVC instructions is also presented to decrease negative interference between control systems. The ICOC system has already been put into practice in some provincial regional power grids in China. Open-looping operation tests have proved the validity of the presented control strategies.
Optical breast shape capture and finite-element mesh generation for electrical impedance tomography
International Nuclear Information System (INIS)
X-ray mammography is the standard for breast cancer screening. The development of alternative imaging modalities is desirable because mammograms expose patients to ionizing radiation. Electrical impedance tomography (EIT) may be used to determine tissue conductivity, a property which is an indicator of cancer presence. EIT is also a low-cost imaging solution and does not involve ionizing radiation. In breast EIT, impedance measurements are made using electrodes placed on the surface of the patient's breast. The complex conductivity of the volume of the breast is estimated by a reconstruction algorithm. EIT reconstruction is a severely ill-posed inverse problem. As a result, noisy instrumentation and incorrect modelling of the electrodes and domain shape produce significant image artefacts. In this paper, we propose a method that has the potential to reduce these errors by accurately modelling the patient breast shape. A 3D hand-held optical scanner is used to acquire the breast geometry and electrode positions. We develop methods for processing the data from the scanner and producing volume meshes accurately matching the breast surface and electrode locations, which can be used for image reconstruction. We demonstrate this method for a plaster breast phantom and a human subject. Using this approach will allow patient-specific finite-element meshes to be generated which has the potential to improve the clinical value of EIT for breast cancer diagnosis
Automatic Tamil lyric generation based on ontological interpretation for semantics
Indian Academy of Sciences (India)
Rajeswari Sridhar; D Jalin Gladis; Kameswaran Ganga; G Dhivya Prabha
2014-02-01
This system proposes an -gram based approach to automatic Tamil lyric generation, by the ontological semantic interpretation of the input scene. The approach is based on identifying the semantics conveyed in the scenario, thereby making the system understand the situation and generate lyrics accordingly. The heart of the system includes the ontological interpretation of the scenario, and the selection of the appropriate tri-grams for generating the lyrics. To fulfill this, we have designed a new ontology with weighted edges, where the edges correspond to a set of sentences, which indicate a relationship, and are represented as a tri-gram. Once the appropriate tri-grams are selected, the root words from these tri-grams are sent to the morphological generator, to form words in their packed form. These words are then assembled to form the final lyrics. Parameters of poetry like rhyme, alliteration, simile, vocative words, etc., are also taken care of by the system. Using this approach, we achieved an average accuracy of 77.3% with respect to the exact semantic details being conveyed in the generated lyrics.
AUTO-LAY: automatic layout generation for procedure flow diagrams
International Nuclear Information System (INIS)
Nuclear Power Plant Procedures can be seen from essentially two viewpoints: the process and the information management. From the first point of view, it is important to supply the knowledge apt to solve problems connected with the control of the process, from the second one the focus of attention is on the knowledge representation, its structure, elicitation and maintenance, formal quality assurance. These two aspects of procedure representation can be considered and solved separately. In particular, methodological, formal and management issues require long and tedious activities, that in most cases constitute a great barrier for procedures development and upgrade. To solve these problems, Ansaldo is developing DIAM, a wide integrated tool for procedure management to support in procedure writing, updating, usage and documentation. One of the most challenging features of DIAM is AUTO-LAY, a CASE sub-tool that, in a complete automatical way, structures parts or complete flow diagrams. This is a feature that is partially present in some other CASE products, that, anyway, do not allow complex graph handling and isomorphism between video and paper representation AUTO-LAY has the unique prerogative to draw graphs of any complexity, to section them in pages, and to automatically compose a document. This has been recognized in the literature as the most important second-generation CASE improvement. (author). 5 refs., 9 figs
Energy Technology Data Exchange (ETDEWEB)
Ricard, L.
2005-12-15
The high level geo-statistic description of the subsurface are often far too detailed for use in routine flow simulators. To make flow simulations tractable, the number of grid blocks has to be reduced: an approximation, still relevant with flow description, is necessary. In this work, we place the emphasis on the scaling procedure from the fine scale model to the multi-scale reservoir model. Two main problems appear: Near wells, faults and channels, the volume of flexible cells may be less than fine ones, so we need to solve a down-scaling problem; Far from these regions, the volume of cells are bigger than fine ones so we need to solve an up-scaling problem. In this work, research has been done on each of these three areas: down-scaling, up-scaling and fluid flow simulation. For each of these subjects, a review, some news improvements and comparative study are proposed. The proposed down-scaling method is build to be compatible with existing data integration methods. The comparative study shows that empirical methods are not enough accurate to solve the problem. Concerning the up-scaling step, the proposed approach is based on an existing method: the perturbed boundary conditions. An extension to unstructured mesh is developed for the inter-cell permeability tensor. The comparative study shows that numerical methods are not always as accurate as expected and the empirical model can be sufficient in lot of cases. A new approach to single-phase fluid flow simulation is developed. This approach can handle with full tensorial permeability fields with source or sink terms.(author)
Towards Automatic Personalized Content Generation for Platform Games
DEFF Research Database (Denmark)
Shaker, Noor; Yannakakis, Georgios N.; Togelius, Julian
2010-01-01
In this paper, we show that personalized levels can be automatically generated for platform games. We build on previous work, where models were derived that predicted player experience based on features of level design and on playing styles. These models are constructed using preference learning......, based on questionnaires administered to players after playing different levels. The contributions of the current paper are (1) more accurate models based on a much larger data set; (2) a mechanism for adapting level design parameters to given players and playing style; (3) evaluation of this adaptation...... mechanism using both algorithmic and human players. The results indicate that the adaptation mechanism effectively optimizes level design parameters for particular players....
Hybrid Generative/Discriminative Learning for Automatic Image Annotation
Yang, Shuang Hong; Zha, Hongyuan
2012-01-01
Automatic image annotation (AIA) raises tremendous challenges to machine learning as it requires modeling of data that are both ambiguous in input and output, e.g., images containing multiple objects and labeled with multiple semantic tags. Even more challenging is that the number of candidate tags is usually huge (as large as the vocabulary size) yet each image is only related to a few of them. This paper presents a hybrid generative-discriminative classifier to simultaneously address the extreme data-ambiguity and overfitting-vulnerability issues in tasks such as AIA. Particularly: (1) an Exponential-Multinomial Mixture (EMM) model is established to capture both the input and output ambiguity and in the meanwhile to encourage prediction sparsity; and (2) the prediction ability of the EMM model is explicitly maximized through discriminative learning that integrates variational inference of graphical models and the pairwise formulation of ordinal regression. Experiments show that our approach achieves both su...
Automatic Generation of Symbolic Model for Parameterized Synchronous Systems
Institute of Scientific and Technical Information of China (English)
Wei-Wen Xu
2004-01-01
With the purpose of making the verification of parameterized system more general and easier, in this paper, a new and intuitive language PSL (Parameterized-system Specification Language) is proposed to specify a class of parameterized synchronous systems. From a PSL script, an automatic method is proposed to generate a constraint-based symbolic model. The model can concisely symbolically represent the collections of global states by counting the number of processes in a given state. Moreover, a theorem has been proved that there is a simulation relation between the original system and its symbolic model. Since the abstract and symbolic techniques are exploited in the symbolic model, state-explosion problem in traditional verification methods is efficiently avoided. Based on the proposed symbolic model, a reachability analysis procedure is implemented using ANSI C++ on UNIX platform. Thus, a complete tool for verifying the parameterized synchronous systems is obtained and tested for some cases. The experimental results show that the method is satisfactory.
Adaptive neuro-fuzzy inference system based automatic generation control
Energy Technology Data Exchange (ETDEWEB)
Hosseini, S.H.; Etemadi, A.H. [Department of Electrical Engineering, Sharif University of Technology, Tehran (Iran)
2008-07-15
Fixed gain controllers for automatic generation control are designed at nominal operating conditions and fail to provide best control performance over a wide range of operating conditions. So, to keep system performance near its optimum, it is desirable to track the operating conditions and use updated parameters to compute control gains. A control scheme based on artificial neuro-fuzzy inference system (ANFIS), which is trained by the results of off-line studies obtained using particle swarm optimization, is proposed in this paper to optimize and update control gains in real-time according to load variations. Also, frequency relaxation is implemented using ANFIS. The efficiency of the proposed method is demonstrated via simulations. Compliance of the proposed method with NERC control performance standard is verified. (author)
Automatic Generation of OWL Ontology from XML Data Source
Yahia, Nora; Ahmed, AbdelWahab
2012-01-01
The eXtensible Markup Language (XML) can be used as data exchange format in different domains. It allows different parties to exchange data by providing common understanding of the basic concepts in the domain. XML covers the syntactic level, but lacks support for reasoning. Ontology can provide a semantic representation of domain knowledge which supports efficient reasoning and expressive power. One of the most popular ontology languages is the Web Ontology Language (OWL). It can represent domain knowledge using classes, properties, axioms and instances for the use in a distributed environment such as the World Wide Web. This paper presents a new method for automatic generation of OWL ontology from XML data sources.
Jou, W.-H.
1982-01-01
An attempt is made to develop a three-dimensional, finite volume computational code for highly swept, twisted, small aspect ratio propeller blades with supersonic tip speeds, in a way that accounts for cascade effects, hub-induced flow, and nonlinear transonic effects. Attention is presently given to the generation of a computational mesh for such a complex propeller configuration, with the aim of sharing developmental process experience. The problem treated is unique, in that blade chord, blade length, hub length and blade-to-blade distance represent several characteristic length scales among which there is considerable disparity. An ad hoc mesh-generation scheme is accordingly developed.
Provenance-Powered Automatic Workflow Generation and Composition
Zhang, J.; Lee, S.; Pan, L.; Lee, T. J.
2015-12-01
In recent years, scientists have learned how to codify tools into reusable software modules that can be chained into multi-step executable workflows. Existing scientific workflow tools, created by computer scientists, require domain scientists to meticulously design their multi-step experiments before analyzing data. However, this is oftentimes contradictory to a domain scientist's daily routine of conducting research and exploration. We hope to resolve this dispute. Imagine this: An Earth scientist starts her day applying NASA Jet Propulsion Laboratory (JPL) published climate data processing algorithms over ARGO deep ocean temperature and AMSRE sea surface temperature datasets. Throughout the day, she tunes the algorithm parameters to study various aspects of the data. Suddenly, she notices some interesting results. She then turns to a computer scientist and asks, "can you reproduce my results?" By tracking and reverse engineering her activities, the computer scientist creates a workflow. The Earth scientist can now rerun the workflow to validate her findings, modify the workflow to discover further variations, or publish the workflow to share the knowledge. In this way, we aim to revolutionize computer-supported Earth science. We have developed a prototyping system to realize the aforementioned vision, in the context of service-oriented science. We have studied how Earth scientists conduct service-oriented data analytics research in their daily work, developed a provenance model to record their activities, and developed a technology to automatically generate workflow starting from user behavior and adaptability and reuse of these workflows for replicating/improving scientific studies. A data-centric repository infrastructure is established to catch richer provenance to further facilitate collaboration in the science community. We have also established a Petri nets-based verification instrument for provenance-based automatic workflow generation and recommendation.
Intelligent control schemes applied to Automatic Generation Control
Directory of Open Access Journals (Sweden)
Dingguo Chen
2016-04-01
Full Text Available Integrating ever increasing amount of renewable generating resources to interconnected power systems has created new challenges to the safety and reliability of today‟s power grids and posed new questions to be answered in the power system modeling, analysis and control. Automatic Generation Control (AGC must be extended to be able to accommodate the control of renewable generating assets. In addition, AGC is mandated to operate in accordance with the NERC‟s Control Performance Standard (CPS criteria, which represent a greater flexibility in relaxing the control of generating resources and yet assuring the stability and reliability of interconnected power systems when each balancing authority operates in full compliance. Enhancements in several aspects to the traditional AGC must be made in order to meet the aforementioned challenges. It is the intention of this paper to provide a systematic, mathematical formulation for AGC as a first attempt in the context of meeting the NERC CPS requirements and integrating renewable generating assets, which has not been seen reported in the literature to the best knowledge of the authors. Furthermore, this paper proposes neural network based predictive control schemes for AGC. The proposed controller is capable of handling complicated nonlinear dynamics in comparison with the conventional Proportional Integral (PI controller which is typically most effective to handle linear dynamics. The neural controller is designed in such a way that it has the capability of controlling the system generation in the relaxed manner so the ACE is controlled to a desired range instead of driving it to zero which would otherwise increase the control effort and cost; and most importantly the resulting system control performance meets the NERC CPS requirements and/or the NERC Balancing Authority’s ACE Limit (BAAL compliance requirements whichever are applicable.
Castro-Mateos, Isaac; Pozo, Jose M.; Lazary, Aron; Frangi, Alejandro F.
2016-03-01
Computational medicine aims at developing patient-specific models to help physicians in the diagnosis and treatment selection for patients. The spine, and other skeletal structures, is an articulated object, composed of rigid bones (vertebrae) and non-rigid parts (intervertebral discs (IVD), ligaments and muscles). These components are usually extracted from different image modalities, involving patient repositioning. In the case of the spine, these models require the segmentation of IVDs from MR and vertebrae from CT. In the literature, there exists a vast selection of segmentations methods, but there is a lack of approaches to align the vertebrae and IVDs. This paper presents a method to create patient-specific finite element meshes for biomechanical simulations, integrating rigid and non-rigid parts of articulated objects. First, the different parts are aligned in a complete surface model. Vertebrae extracted from CT are rigidly repositioned in between the IVDs, initially using the IVDs location and then refining the alignment using the MR image with a rigid active shape model algorithm. Finally, a mesh morphing algorithm, based on B-splines, is employed to map a template finite-element (volumetric) mesh to the patient-specific surface mesh. This morphing reduces possible misalignments and guarantees the convexity of the model elements. Results show that the accuracy of the method to align vertebrae into MR, together with IVDs, is similar to that of the human observers. Thus, this method is a step forward towards the automation of patient-specific finite element models for biomechanical simulations.
Energy Technology Data Exchange (ETDEWEB)
Flandrin, N.
2005-09-15
During the exploitation of an oil reservoir, it is important to predict the recovery of hydrocarbons and to optimize its production. A better comprehension of the physical phenomena requires to simulate 3D multiphase flows in increasingly complex geological structures. In this thesis, we are interested in this spatial discretization and we propose to extend in 3D the 2D hybrid model proposed by IFP in 1998 that allows to take directly into account in the geometry the radial characteristics of the flows. In these hybrid meshes, the wells and their drainage areas are described by structured radial circular meshes and the reservoirs are represented by structured meshes that can be a non uniform Cartesian grid or a Corner Point Geometry grids. In order to generate a global conforming mesh, unstructured transition meshes based on power diagrams and satisfying finite volume properties are used to connect the structured meshes together. Two methods have been implemented to generate these transition meshes: the first one is based on a Delaunay triangulation, the other one uses a frontal approach. Finally, some criteria are introduced to measure the quality of the transition meshes and optimization procedures are proposed to increase this quality under finite volume properties constraints. (author)
Reaction Mechanism Generator: Automatic construction of chemical kinetic mechanisms
Gao, Connie W.; Allen, Joshua W.; Green, William H.; West, Richard H.
2016-06-01
Reaction Mechanism Generator (RMG) constructs kinetic models composed of elementary chemical reaction steps using a general understanding of how molecules react. Species thermochemistry is estimated through Benson group additivity and reaction rate coefficients are estimated using a database of known rate rules and reaction templates. At its core, RMG relies on two fundamental data structures: graphs and trees. Graphs are used to represent chemical structures, and trees are used to represent thermodynamic and kinetic data. Models are generated using a rate-based algorithm which excludes species from the model based on reaction fluxes. RMG can generate reaction mechanisms for species involving carbon, hydrogen, oxygen, sulfur, and nitrogen. It also has capabilities for estimating transport and solvation properties, and it automatically computes pressure-dependent rate coefficients and identifies chemically-activated reaction paths. RMG is an object-oriented program written in Python, which provides a stable, robust programming architecture for developing an extensible and modular code base with a large suite of unit tests. Computationally intensive functions are cythonized for speed improvements.
Kinetic Solvers with Adaptive Mesh in Phase Space
Arslanbekov, Robert R; Kolobov, Vladimir I; Frolova, Anna A.
2013-01-01
An Adaptive Mesh in Phase Space (AMPS) methodology has been developed for solving multi-dimensional kinetic equations by the discrete velocity method. A Cartesian mesh for both configuration (r) and velocity (v) spaces is produced using a tree of trees data structure. The mesh in r-space is automatically generated around embedded boundaries and dynamically adapted to local solution properties. The mesh in v-space is created on-the-fly for each cell in r-space. Mappings between neighboring v-s...
Reinforcement-Based Fuzzy Neural Network ontrol with Automatic Rule Generation
Institute of Scientific and Technical Information of China (English)
无
1999-01-01
A reinforcemen-based fuzzy neural network control with automatic rule generation RBFNNC) is pro-posed. A set of optimized fuzzy control rules can be automatically generated through reinforcement learning based onthe state variables of object system. RBFNNC was applied to a cart-pole balancing system and simulation resultshows significant improvements on the rule generation.
Automatic Overset Grid Generation with Heuristic Feedback Control
Robinson, Peter I.
2001-01-01
An advancing front grid generation system for structured Overset grids is presented which automatically modifies Overset structured surface grids and control lines until user-specified grid qualities are achieved. The system is demonstrated on two examples: the first refines a space shuttle fuselage control line until global truncation error is achieved; the second advances, from control lines, the space shuttle orbiter fuselage top and fuselage side surface grids until proper overlap is achieved. Surface grids are generated in minutes for complex geometries. The system is implemented as a heuristic feedback control (HFC) expert system which iteratively modifies the input specifications for Overset control line and surface grids. It is developed as an extension of modern control theory, production rules systems and subsumption architectures. The methodology provides benefits over the full knowledge lifecycle of an expert system for knowledge acquisition, knowledge representation, and knowledge execution. The vector/matrix framework of modern control theory systematically acquires and represents expert system knowledge. Missing matrix elements imply missing expert knowledge. The execution of the expert system knowledge is performed through symbolic execution of the matrix algebra equations of modern control theory. The dot product operation of matrix algebra is generalized for heuristic symbolic terms. Constant time execution is guaranteed.
Automatic speech recognition for report generation in computed tomography
International Nuclear Information System (INIS)
Purpose: A study was performed to compare the performance of automatic speech recognition (ASR) with conventional transcription. Materials and Methods: 100 CT reports were generated by using ASR and 100 CT reports were dictated and written by medical transcriptionists. The time for dictation and correction of errors by the radiologist was assessed and the type of mistakes was analysed. The text recognition rate was calculated in both groups and the average time between completion of the imaging study by the technologist and generation of the written report was assessed. A commercially available speech recognition technology (ASKA Software, IBM Via Voice) running of a personal computer was used. Results: The time for the dictation using digital voice recognition was 9.4±2.3 min compared to 4.5±3.6 min with an ordinary Dictaphone. The text recognition rate was 97% with digital voice recognition and 99% with medical transcriptionists. The average time from imaging completion to written report finalisation was reduced from 47.3 hours with medical transcriptionists to 12.7 hours with ASR. The analysis of misspellings demonstrated (ASR vs. medical transcriptionists): 3 vs. 4 for syntax errors, 0 vs. 37 orthographic mistakes, 16 vs. 22 mistakes in substance and 47 vs. erroneously applied terms. Conclusions: The use of digital voice recognition as a replacement for medical transcription is recommendable when an immediate availability of written reports is necessary. (orig.)
Vibrating-mesh nebulization of liposomes generated using an ethanol-based proliposome technology.
Elhissi, Abdelbary; Gill, Hardyal; Ahmed, Waqar; Taylor, Kevin
2011-06-01
This is the first study that evaluates the influence of the compartmental design of the micropump Aeroneb Go nebulizer and the viscosity of a proliposome hydration medium on vibrating-mesh aerosolization of liposomes. Ethanol-based proliposomes comprising soya phosphatidylcholine and cholesterol (1:1 mole ratio) were hydrated by using isotonic NaCl (0.9%) or sucrose (9.25%) solutions to generate liposomes that entrapped approximately 61% of the hydrophilic drug, salbutamol sulphate. Liposomes were aerosolized by the nebulizer to a two-stage impinger. For both formulations, the aerosol mass output was higher than the phospholipid output, indicating some accumulation of large liposomes or liposome aggregate within the nebulizer. Using NaCl (0.9%) solution as the dispersion medium, aerosol droplet size was much smaller and aerosol mass and phospholipid outputs were higher. This was attributed to the lower viscosity of the NaCl solution, resulting in a reduced retention of the aerosols in the "trap" of the nebulizer. For the entrapped salbutamol sulphate, although the "fine particle fraction" was relatively high (57.44%), size reduction of the liposomes during nebulization caused marked losses of the drug originally entrapped. Overall, liposomes generated from proliposomes when using this nebulizer showed high nebulization output and small droplet size. However, further work is required to reduce the losses of the originally entrapped drug from liposomes. PMID:20684671
Automatic ID heat load generation in ANSYS code
International Nuclear Information System (INIS)
Detailed power density profiles are critical in the execution of a thermal analysis using a finite element (FE) code such as ANSYS. Unfortunately, as yet there is no easy way to directly input the precise power profiles into ANSYS. A straight-forward way to do this is to hand-calculate the power of each node or element and then type the data into the code. Every time a change is made to the FE model, the data must be recalculated and reentered. One way to solve this problem is to generate a set of discrete data, using another code such as PHOTON2, and curve-fit the data. Using curve-fitted formulae has several disadvantages. It is time consuming because of the need to run a second code for generation of the data, curve-fitting, and doing the data check, etc. Additionally, because there is no generality for different beamlines or different parameters, the above work must be repeated for each case. And, errors in the power profiles due to curve-fitting result in errors in the analysis. To solve the problem once and for all and with the capability to apply to any insertion device (ID), a program for ED power profile was written in ANSYS Parametric Design Language (APDL). This program is implemented as an ANSYS command with input parameters of peak magnetic field, deflection parameter, length of ID, and distance from the source. Once the command is issued, all the heat load will be automatically generated by the code
International Nuclear Information System (INIS)
A combined procedure for two-dimensional Delaunay mesh generation algorithm and an adaptive remeshing technique with higher-order compressible flow solver is presented. A pseudo-code procedure is described for the adaptive remeshing technique. The flux-difference splitting scheme with a modified multidimensional dissipation for high-speed compressible flow analysis on unstructured meshes is proposed. The scheme eliminates nonphysical flow solutions such as the spurious bump of the carbuncle phenomenon observed from the bow shock of the flow over a blunt body and the oscillation in the odd-even grid perturbation in a straight duct for the Quirk's odd-even decoupling test. The proposed scheme is further extended to achieve higher-order spatial and temporal solution accuracy. The performance of the combined procedure is evaluated on unstructured triangular meshes by solving several steady-state and transient high-speed compressible flow problems
Development of tools for automatic generation of PLC code
Koutli, Maria; Rochez, Jacques
This Master thesis was performed at CERN and more specifically in the EN-ICE-PLC section. The Thesis describes the integration of two PLC platforms, that are based on CODESYS development tool, to the CERN defined industrial framework, UNICOS. CODESYS is a development tool for PLC programming, based on IEC 61131-3 standard, and is adopted by many PLC manufacturers. The two PLC development environments are, the SoMachine from Schneider and the TwinCAT from Beckhoff. The two CODESYS compatible PLCs, should be controlled by the SCADA system of Siemens, WinCC OA. The framework includes a library of Function Blocks (objects) for the PLC programs and a software for automatic generation of the PLC code based on this library, called UAB. The integration aimed to give a solution that is shared by both PLC platforms and was based on the PLCOpen XML scheme. The developed tools were demonstrated by creating a control application for both PLC environments and testing of the behavior of the code of the library.
Learning Techniques for Automatic Test Pattern Generation using Boolean Satisfiability
Directory of Open Access Journals (Sweden)
Liu Xin
2013-07-01
Full Text Available Automatic Test Pattern Generation (ATPG is one of the core problems in testing of digital circuits. ATPG algorithms based on Boolean Satisfiability (SAT turned out to be very powerful, due to great advances in the performance of satisfiability solvers for propositional logic in the last two decades. SAT-based ATPG clearly outperforms classical approaches especially for hard-to-detect faults. But its inaccessibility of structural information and don’t care, there exists the over-specification problem of input patterns. In this paper we present techniques to delve into an additional layer to make use of structural properties of the circuit and value justification relations to a generic SAT algorithm. It joins binary decision graphs (BDD and SAT techniques to improve the efficiency of ATPG. It makes a study of inexpensive reconvergent fanout analysis of circuit to gather information on the local signal correlation by using BDD learning, then uses the above learned information to restrict and focus the overall search space of SAT-based ATPG. The learning technique is effective and lightweight. Experimental results show the effectiveness of the approach.
Incorporating Feature-Based Annotations into Automatically Generated Knowledge Representations
Lumb, L. I.; Lederman, J. I.; Aldridge, K. D.
2006-12-01
Earth Science Markup Language (ESML) is efficient and effective in representing scientific data in an XML- based formalism. However, features of the data being represented are not accounted for in ESML. Such features might derive from events (e.g., a gap in data collection due to instrument servicing), identifications (e.g., a scientifically interesting area/volume in an image), or some other source. In order to account for features in an ESML context, we consider them from the perspective of annotation, i.e., the addition of information to existing documents without changing the originals. Although it is possible to extend ESML to incorporate feature-based annotations internally (e.g., by extending the XML schema for ESML), there are a number of complicating factors that we identify. Rather than pursuing the ESML-extension approach, we focus on an external representation for feature-based annotations via XML Pointer Language (XPointer). In previous work (Lumb &Aldridge, HPCS 2006, IEEE, doi:10.1109/HPCS.2006.26), we have shown that it is possible to extract relationships from ESML-based representations, and capture the results in the Resource Description Format (RDF). Thus we explore and report on this same requirement for XPointer-based annotations of ESML representations. As in our past efforts, the Global Geodynamics Project (GGP) allows us to illustrate with a real-world example this approach for introducing annotations into automatically generated knowledge representations.
Power generation using carbon mesh cathodes with different diffusion layers in microbial fuel cells
Luo, Yong
2011-11-01
An inexpensive carbon material, carbon mesh, was examined to replace the more expensive carbon cloth usually used to make cathodes in air-cathode microbial fuel cells (MFCs). Three different diffusion layers were tested using carbon mesh: poly(dimethylsiloxane) (PDMS), polytetrafluoroethylene (PTFE), and Goretex cloth. Carbon mesh with a mixture of PDMS and carbon black as a diffusion layer produced a maximum power density of 1355 ± 62 mW m -2 (normalized to the projected cathode area), which was similar to that obtained with a carbon cloth cathode (1390 ± 72 mW m-2). Carbon mesh with a PTFE diffusion layer produced only a slightly lower (6.6%) maximum power density (1303 ± 48 mW m-2). The Coulombic efficiencies were a function of current density, with the highest value for the carbon mesh and PDMS (79%) larger than that for carbon cloth (63%). The cost of the carbon mesh cathode with PDMS/Carbon or PTFE (excluding catalyst and binder costs) is only 2.5% of the cost of the carbon cloth cathode. These results show that low cost carbon materials such as carbon mesh can be used as the cathode in an MFC without reducing the performance compared to more expensive carbon cloth. © 2011 Elsevier B.V.
Automatic generation of digital anthropomorphic phantoms from simulated MRI acquisitions
Lindsay, C.; Gennert, M. A.; KÓ§nik, A.; Dasari, P. K.; King, M. A.
2013-03-01
In SPECT imaging, motion from patient respiration and body motion can introduce image artifacts that may reduce the diagnostic quality of the images. Simulation studies using numerical phantoms with precisely known motion can help to develop and evaluate motion correction algorithms. Previous methods for evaluating motion correction algorithms used either manual or semi-automated segmentation of MRI studies to produce patient models in the form of XCAT Phantoms, from which one calculates the transformation and deformation between MRI study and patient model. Both manual and semi-automated methods of XCAT Phantom generation require expertise in human anatomy, with the semiautomated method requiring up to 30 minutes and the manual method requiring up to eight hours. Although faster than manual segmentation, the semi-automated method still requires a significant amount of time, is not replicable, and is subject to errors due to the difficulty of aligning and deforming anatomical shapes in 3D. We propose a new method for matching patient models to MRI that extends the previous semi-automated method by eliminating the manual non-rigid transformation. Our method requires no user supervision and therefore does not require expert knowledge of human anatomy to align the NURBs to anatomical structures in the MR image. Our contribution is employing the SIMRI MRI simulator to convert the XCAT NURBs to a voxel-based representation that is amenable to automatic non-rigid registration. Then registration is used to transform and deform the NURBs to match the anatomy in the MR image. We show that our automated method generates XCAT Phantoms more robustly and significantly faster than the previous semi-automated method.
Waldrep, J C; Dhand, R
2008-04-01
Recent technological advances and improved nebulizer designs have overcome many limitations of jet nebulizers. Newer devices employ a vibrating mesh or aperture plate (VM/AP) for the generation of therapeutic aerosols with consistent, increased efficiency, predominant aerosol fine particle fractions, low residuals, and the ability to nebulize even microliter volumes. These enhancements are achieved through several different design features and include improvements that promote patient compliance, such as compact design, portability, shorter treatment durations, and quiet operation. Current VM/AP devices in clinical use are the Omron MicroAir, the Nektar Aeroneb, and the Pari eFlow. However, some devices are only approved for use with specific medications. Development of "smart nebulizers" such as the Respironics I-neb couple VM technologies with coordinated delivery and optimized inhalation patterns to enhance inhaled drug delivery of specialized, expensive formulations. Ongoing development of advanced aerosol technologies should improve clinical outcomes and continue to expand therapeutic options as newer inhaled drugs become available. PMID:18393813
Shape Metamorphosis – Automatic 3D Mesh Generation, Topology Verification and Analysis
Directory of Open Access Journals (Sweden)
Tomasz Zawadzki
2013-12-01
Full Text Available The objective of this paper is a 3D shape construction that benefits from discrete and continuous modelling approaches. The proposed solution addresses the problem of automated modelling of virtual structures such as caves, buildings and clouds and presents an alternative solution in the form of a hybrid system. Parallel realizations of these solutions are tested on various processors of graphic cards with the use of NVIDIA ‘CUDA’ technology. This paper describes the implementation of algorithms (approaches and their parallel speedup, efficiency, throughput. Modelled structures are geometrically complex, with an inner graph structure more optimized than in the classical CSG approach. Moreover, they can be rendered up to very high levels of visual realism. In this paper we mainly focus on the description of the algorithm. We also propose very useful measures that can be used to verify the model geometry.
Rodriguez, David L. (Inventor); Sturdza, Peter (Inventor)
2013-01-01
Fluid-flow simulation over a computer-generated aircraft surface is generated using inviscid and viscous simulations. A fluid-flow mesh of fluid cells is obtained. At least one inviscid fluid property for the fluid cells is determined using an inviscid fluid simulation that does not simulate fluid viscous effects. A set of intersecting fluid cells that intersects the aircraft surface are identified. One surface mesh polygon of the surface mesh is identified for each intersecting fluid cell. A boundary-layer prediction point for each identified surface mesh polygon is determined. At least one boundary-layer fluid property for each boundary-layer prediction point is determined using the at least one inviscid fluid property of the corresponding intersecting fluid cell and a boundary-layer simulation that simulates fluid viscous effects. At least one updated fluid property for at least one fluid cell is determined using the at least one boundary-layer fluid property and the inviscid fluid simulation.
PUS Services Software Building Block Automatic Generation for Space Missions
Candia, S.; Sgaramella, F.; Mele, G.
2008-08-01
The Packet Utilization Standard (PUS) has been specified by the European Committee for Space Standardization (ECSS) and issued as ECSS-E-70-41A to define the application-level interface between Ground Segments and Space Segments. The ECSS-E- 70-41A complements the ECSS-E-50 and the Consultative Committee for Space Data Systems (CCSDS) recommendations for packet telemetry and telecommand. The ECSS-E-70-41A characterizes the identified PUS Services from a functional point of view and the ECSS-E-70-31 standard specifies the rules for their mission-specific tailoring. The current on-board software design for a space mission implies the production of several PUS terminals, each providing a specific tailoring of the PUS services. The associated on-board software building blocks are developed independently, leading to very different design choices and implementations even when the mission tailoring requires very similar services (from the Ground operative perspective). In this scenario, the automatic production of the PUS services building blocks for a mission would be a way to optimize the overall mission economy and improve the robusteness and reliability of the on-board software and of the Ground-Space interactions. This paper presents the Space Software Italia (SSI) activities for the development of an integrated environment to support: the PUS services tailoring activity for a specific mission. the mission-specific PUS services configuration. the generation the UML model of the software building block implementing the mission-specific PUS services and the related source code, support documentation (software requirements, software architecture, test plans/procedures, operational manuals), and the TM/TC database. The paper deals with: (a) the project objectives, (b) the tailoring, configuration, and generation process, (c) the description of the environments supporting the process phases, (d) the characterization of the meta-model used for the generation, (e) the
The geometry of r-adaptive meshes generated using optimal transport methods
Budd, C. J.; Russell, R. D.; Walsh, E.
2015-02-01
The principles of mesh equidistribution and alignment play a fundamental role in the design of adaptive methods, and a metric tensor and mesh metric are useful theoretical tools for understanding a method's level of mesh alignment, or anisotropy. We consider a mesh redistribution method based on the Monge-Ampère equation which combines equidistribution of a given scalar density function with optimal transport. It does not involve explicit use of a metric tensor, although such a tensor must exist for the method, and an interesting question to ask is whether or not the alignment produced by the metric gives an anisotropic mesh. For model problems with a linear feature and with a radially symmetric feature, we derive the exact form of the metric, which involves expressions for its eigenvalues and eigenvectors. The eigenvectors are shown to be orthogonal and tangential to the feature, and the ratio of the eigenvalues (corresponding to the level of anisotropy) is shown to depend, both locally and globally, on the value of the density function and the amount of curvature. We thereby demonstrate how the optimal transport method produces an anisotropic mesh along a given feature while equidistributing a suitably chosen scalar density function. Numerical results are given to verify these results and to demonstrate how the analysis is useful for problems involving more complex features, including for a non-trivial time dependant nonlinear PDE which evolves narrow and curved reaction fronts.
Automatic Grasp Generation and Improvement for Industrial Bin-Picking
DEFF Research Database (Denmark)
Kraft, Dirk; Ellekilde, Lars-Peter; Rytz, Jimmy Alison
2014-01-01
and achieve comparable results and that our learning approach can improve system performance significantly. Automatic bin-picking is an important industrial process that can lead to significant savings and potentially keep production in countries with high labour cost rather than outsourcing it. The presented...... work allows to minimize cycle time as well as setup cost, which are essential factors in automatic bin-picking. It therefore leads to a wider applicability of bin-picking in industry....
Historical Author Affiliations Assist Verification of Automatically Generated MEDLINE® Citations
Sabir, Tehseen F.; Hauser, Susan E.; Thoma, George R.
2006-01-01
High OCR error rates encountered in author affiliations increase the manual labor needed to verify MEDLINE citations automatically created from scanned journal articles. This is due to poor OCR recognition of the small text and italics frequently used in printed affiliations. Using author-affiliation relationships found in existing MEDLINE records, the SeekAffiliation (SA) program automatically finds potentially correct and complete affiliations, thereby reducing manual effort and increasing ...
Automatic Generation of Remote Visualization Tools with WATT
Jensen, P. A.; Bollig, E. F.; Yuen, D. A.; Erlebacher, G.; Momsen, A. R.
2006-12-01
The ever increasing size and complexity of geophysical and other scientific datasets has forced developers to turn to more powerful alternatives for visualizing results of computations and experiments. These alternative need to be faster, scalable, more efficient, and able to be run on large machines. At the same time, advances in scripting languages and visualization libraries have significantly decreased the development time of smaller, desktop visualization tools. Ideally, programmers would be able to develop visualization tools in a high-level, local, scripted environment and then automatically convert their programs into compiled, remote visualization tools for integration into larger computation environments. The Web Automation and Translation Toolkit (WATT) [1] converts a Tcl script for the Visualization Toolkit (VTK) [2] into a standards-compliant web service. We will demonstrate the used of WATT for the automated conversion of a desktop visualization application (written in Tcl for VTK) into a remote visualization service of interest to geoscientists. The resulting service will allow real-time access to a large dataset through the Internet, and will be easily integrated into the existing architecture of the Virtual Laboratory for Earth and Planetary Materials (VLab) [3]. [1] Jensen, P.A., Yuen, D.A., Erlebacher, G., Bollig, E.F., Kigelman, D.G., Shukh, E.A., Automated Generation of Web Services for Visualization Toolkits, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract IN42A-06, 2005. [2] The Visualization Toolkit, http://www.vtk.org [3] The Virtual Laboratory for Earth and Planetary Materials, http://vlab.msi.umn.edu
Dongmin Seo; Hanmin Jung; Won-Kyung Sung; Dukyun Nam
2014-01-01
By 2026, Korea is expected to surpass the UN’s definition of an aged society and reach the level of a superaged society. With an aging population come increased disorders involving the spine. To prevent unnecessary spinal surgery and support scientific diagnosis of spinal disease and systematic prediction of treatment outcomes, we have been developing e-Spine, which is a computer simulation model of the human spine. In this paper, we present the Korean spine database and automatic surface mes...
How to model wireless mesh networks topology
International Nuclear Information System (INIS)
The specification of network connectivity model or topology is the beginning of design and analysis in Computer Network researches. Wireless Mesh Networks is an autonomic network that is dynamically self-organised, self-configured while the mesh nodes establish automatic connectivity with the adjacent nodes in the relay network of wireless backbone routers. Researches in Wireless Mesh Networks range from node deployment to internetworking issues with sensor, Internet and cellular networks. These researches require modelling of relationships and interactions among nodes including technical characteristics of the links while satisfying the architectural requirements of the physical network. However, the existing topology generators model geographic topologies which constitute different architectures, thus may not be suitable in Wireless Mesh Networks scenarios. The existing methods of topology generation are explored, analysed and parameters for their characterisation are identified. Furthermore, an algorithm for the design of Wireless Mesh Networks topology based on square grid model is proposed in this paper. The performance of the topology generated is also evaluated. This research is particularly important in the generation of a close-to-real topology for ensuring relevance of design to the intended network and validity of results obtained in Wireless Mesh Networks researches
A strategy for automatically generating programs in the lucid programming language
Johnson, Sally C.
1987-01-01
A strategy for automatically generating and verifying simple computer programs is described. The programs are specified by a precondition and a postcondition in predicate calculus. The programs generated are in the Lucid programming language, a high-level, data-flow language known for its attractive mathematical properties and ease of program verification. The Lucid programming is described, and the automatic program generation strategy is described and applied to several example problems.
International Nuclear Information System (INIS)
describe the user's scheme. According to the mesh grid refinement options, GGTM introduces further co-ordinate values, which complete the input mesh grid. A loop for each cell is performed to determine the zone and the material to be attributed to the cell. The cell is ideally represented by its centre and it is relatively simple to determine which material zone the cell belongs to. Material zones may have very complicated geometrical shapes in space thanks to the combinatorial geometry among volumes existing in GGTM. Moreover, the priority parameter associated to each material zone can easily solve any overlapping situation among zones. Fixed neutron sources, if any, are adapted to the mesh refinement at the same time. As from version 5.0, GGTM can optionally calculate errors in volume values due to the stair-cased approximation in geometry. GGTM considers a 'very' refined uniform sub-grid for those single meshes cutting more than one material zone at zone interfaces and works in same way as previously described in the mesh attribution to zones for each single sub-mesh. This method lets users calculate the exact material zone volume values with great precision, independently of the geometry complexity and lets GGTM automatically update material zone densities to conserve mass. As for the plot programs DDM, DTM2 and DTM3, they do not make any value interpolations among cell values to have contours, when used as post-processors or to plot any fixed neutron source distribution; they simply attribute the entire single mesh grid cell the colour corresponding to the adopted value scale. This simple and fast method lets users faithfully reproduce transport results and overlap material, zone, body or mesh borders on the same plots without overcrowding them with too many lines. 3 - Restrictions on the complexity of the problem: Only a continuous space mesh grid can be generated by GGDM and GGTM and input to DDM, DTM2, DTM3, RVARSCL, COMPARE and MKSRC
International Nuclear Information System (INIS)
Improving speed and quality of Eddy Current non-destructive testing of steam generator tubes leads to automatize all processes that contribute to diagnosis. This paper describes how we use signal processing, pattern recognition and artificial intelligence to build a software package that is able to automatically provide an efficient diagnosis. (authors). 2 figs., 5 refs
International Nuclear Information System (INIS)
An efficient hydraulic optimization procedure, suitable for industrial use, requires an advanced optimization tool (EASY software), a fast solver (block coupled CFD) and a flexible geometry generation tool. EASY optimization software is a PCA-driven metamodel-assisted Evolutionary Algorithm (MAEA (PCA)) that can be used in both single- (SOO) and multiobjective optimization (MOO) problems. In MAEAs, low cost surrogate evaluation models are used to screen out non-promising individuals during the evolution and exclude them from the expensive, problem specific evaluation, here the solution of Navier-Stokes equations. For additional reduction of the optimization CPU cost, the PCA technique is used to identify dependences among the design variables and to exploit them in order to efficiently drive the application of the evolution operators. To further enhance the hydraulic optimization procedure, a very robust and fast Navier-Stokes solver has been developed. This incompressible CFD solver employs a pressure-based block-coupled approach, solving the governing equations simultaneously. This method, apart from being robust and fast, also provides a big gain in terms of computational cost. In order to optimize the geometry of hydraulic machines, an automatic geometry and mesh generation tool is necessary. The geometry generation tool used in this work is entirely based on b-spline curves and surfaces. In what follows, the components of the tool chain are outlined in some detail and the optimization results of hydraulic machine components are shown in order to demonstrate the performance of the presented optimization procedure
Automated Theorem Proving for Cryptographic Protocols with Automatic Attack Generation
Jan Juerjens; Thomas A. Kuhn
2016-01-01
Automated theorem proving is both automatic and can be quite efficient. When using theorem proving approaches for security protocol analysis, however, the problem is often that absence of a proof of security of a protocol may give little hint as to where the security weakness lies, to enable the protocol designer to improve the protocol. For our approach to verify cryptographic protocols using automated theorem provers for first-order logic (such as e-SETHEO or SPASS), we demonstrate a method...
Research on Object-oriented Software Testing Cases of Automatic Generation
Directory of Open Access Journals (Sweden)
Junli Zhang
2013-11-01
Full Text Available In the research on automatic generation of testing cases, there are different execution paths under drivers of different testing cases. The probability of these paths being executed is also different. For paths which are easy to be executed, more redundant testing case tend to be generated; But only fewer testing cases are generated for the control paths which are hard to be executed. Genetic algorithm can be used to instruct the automatic generation of testing cases. For the former paths, it can restrict the generation of these kinds of testing cases. On the contrary, the algorithm will encourage the generation of such testing cases as much as possible. So based on the study on the technology of path-oriented testing case automatic generation, the genetic algorithm is adopted to construct the process of automatic generation. According to the triggering path during the dynamic execution of program, the generated testing cases are separated into different equivalence class. The number of testing case is adjusted dynamicly by the fitness corresponding to the paths. The method can create a certain number of testing cases for each execution path to ensure the sufficiency. It also reduces redundant testing cases so it is an effective method for automatic generation of testing cases.
National Aeronautics and Space Administration — The following background technology is described in Part 5: Run-time Verification (RV), White Box Automatic Test Generation (WBATG). Part 5 also describes how WBATG...
Isotropic 2D quadrangle meshing with size and orientation control
Pellenard, Bertrand
2011-12-01
We propose an approach for automatically generating isotropic 2D quadrangle meshes from arbitrary domains with a fine control over sizing and orientation of the elements. At the heart of our algorithm is an optimization procedure that, from a coarse initial tiling of the 2D domain, enforces each of the desirable mesh quality criteria (size, shape, orientation, degree, regularity) one at a time, in an order designed not to undo previous enhancements. Our experiments demonstrate how well our resulting quadrangle meshes conform to a wide range of input sizing and orientation fields.
The challenge of Automatic Level Generation for platform videogames based on Stories and Quests
Mourato, Fausto; Birra, Fernando; Santos, Manuel Próspero dos
2013-01-01
In this article we bring the concepts of narrativism and ludology to automatic level generation for platform videogames. The initial motivation is to understand how this genre has been used as a storytelling medium. Based on a narrative theory of games, the differences among several titles have been identified. In addition, we propose a set of abstraction layers to describe the content of a quest-based story in the particular context of videogames. Regarding automatic level generation for pla...
A system for automatically generating documentation for (C)LP programs
Hermenegildo, Manuel V.
2000-01-01
We describe lpdoc, a tool which generates documentation manuals automatically from one or more logic program source files, written in ISO-Prolog, Ciao, and other (C)LP languages. It is particularly useful for documenting library modules, for which it automatically generates a rich description of the module interface. However, it can also be used quite successfully to document full applications. A fundamental advantage of using lpdoc is that it helps maintaining a true correspondence between t...
Institute of Scientific and Technical Information of China (English)
梁松新; 张景中
1999-01-01
By establishing a complete discrimination system for polynomials, the problem of complete root classification for polynomials with complex coefficients is utterly solved, furthermore, the algorithm obtained is made into a general program in Maple, which enables the complete discrimination system and complete root classification of a polynomial to be automatically generated by computer, without any human intervention. Besides, by using the automatic generation of root classification, a method to determine the positive definiteness of a polynomial in one or two indeterminates is automatically presented.
Kinetic Solvers with Adaptive Mesh in Phase Space
Arslanbekov, Robert R; Frolova, Anna A
2013-01-01
An Adaptive Mesh in Phase Space (AMPS) methodology has been developed for solving multi-dimensional kinetic equations by the discrete velocity method. A Cartesian mesh for both configuration (r) and velocity (v) spaces is produced using a tree of trees data structure. The mesh in r-space is automatically generated around embedded boundaries and dynamically adapted to local solution properties. The mesh in v-space is created on-the-fly for each cell in r-space. Mappings between neighboring v-space trees implemented for the advection operator in configuration space. We have developed new algorithms for solving the full Boltzmann and linear Boltzmann equations with AMPS. Several recent innovations were used to calculate the full Boltzmann collision integral with dynamically adaptive mesh in velocity space: importance sampling, multi-point projection method, and the variance reduction method. We have developed an efficient algorithm for calculating the linear Boltzmann collision integral for elastic and inelastic...
International Nuclear Information System (INIS)
In this paper, we propose a new approach to the development of the automatic vision system to examine and repair the steam generator tubes at remote distance. In nuclear power plants, workers are reluctant of works in steam generator because of the high radiation environment and limited working space. It is strongly recommended that the examination and maintenance works be done by an automatic system for the protection of the operator from the radiation exposure. Digital signal processors are used in implementing real time recognition and examination of steam generator tubes in the proposed vision system. Performance of proposed digital vision system is illustrated by simulation and experiment for similar steam generator model
Automatic Generation Control Strategy Based on Balance of Daily Electric Energy
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
An automatic generation control strategy based on balance of daily total electric energy is put forward. It makes the balance between actual total generated energy controlled by automatic generation system and planned total energy on base of area control error, and makes the actual 24-hour active power load curve to approach the planned load curve. The generated energy is corrected by velocity weighting factor so that it conducts dynamic regulation and reaches the speed of response. Homologous strategy is used according to the real-time data in the operation of automatic generation control. Results of simulation are perfect and power energy compensation control with ideal effect can be achieved in the particular duration.
AROMA: Automatic Generation of Radio Maps for Localization Systems
Eleryan, Ahmed; Youssef, Moustafa
2010-01-01
WLAN localization has become an active research field recently. Due to the wide WLAN deployment, WLAN localization provides ubiquitous coverage and adds to the value of the wireless network by providing the location of its users without using any additional hardware. However, WLAN localization systems usually require constructing a radio map, which is a major barrier of WLAN localization systems' deployment. The radio map stores information about the signal strength from different signal strength streams at selected locations in the site of interest. Typical construction of a radio map involves measurements and calibrations making it a tedious and time-consuming operation. In this paper, we present the AROMA system that automatically constructs accurate active and passive radio maps for both device-based and device-free WLAN localization systems. AROMA has three main goals: high accuracy, low computational requirements, and minimum user overhead. To achieve high accuracy, AROMA uses 3D ray tracing enhanced wi...
Improving Statistical Language Model Performance with Automatically Generated Word Hierarchies
McMahon, J; Mahon, John Mc
1995-01-01
An automatic word classification system has been designed which processes word unigram and bigram frequency statistics extracted from a corpus of natural language utterances. The system implements a binary top-down form of word clustering which employs an average class mutual information metric. Resulting classifications are hierarchical, allowing variable class granularity. Words are represented as structural tags --- unique $n$-bit numbers the most significant bit-patterns of which incorporate class information. Access to a structural tag immediately provides access to all classification levels for the corresponding word. The classification system has successfully revealed some of the structure of English, from the phonemic to the semantic level. The system has been compared --- directly and indirectly --- with other recent word classification systems. Class based interpolated language models have been constructed to exploit the extra information supplied by the classifications and some experiments have sho...
Generation of the 30 M-Mesh Global Digital Surface Model by Alos Prism
Tadono, T.; Nagai, H.; Ishida, H.; Oda, F.; Naito, S.; Minakawa, K.; Iwamoto, H.
2016-06-01
Topographical information is fundamental to many geo-spatial related information and applications on Earth. Remote sensing satellites have the advantage in such fields because they are capable of global observation and repeatedly. Several satellite-based digital elevation datasets were provided to examine global terrains with medium resolutions e.g. the Shuttle Radar Topography Mission (SRTM), the global digital elevation model by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER GDEM). A new global digital surface model (DSM) dataset using the archived data of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS, nicknamed "Daichi") has been completed on March 2016 by Japan Aerospace Exploration Agency (JAXA) collaborating with NTT DATA Corp. and Remote Sensing Technology Center, Japan. This project is called "ALOS World 3D" (AW3D), and its dataset consists of the global DSM dataset with 0.15 arcsec. pixel spacing (approx. 5 m mesh) and ortho-rectified PRISM image with 2.5 m resolution. JAXA is also processing the global DSM with 1 arcsec. spacing (approx. 30 m mesh) based on the AW3D DSM dataset, and partially releasing it free of charge, which calls "ALOS World 3D 30 m mesh" (AW3D30). The global AW3D30 dataset will be released on May 2016. This paper describes the processing status, a preliminary validation result of the AW3D30 DSM dataset, and its public release status. As a summary of the preliminary validation of AW3D30 DSM, 4.40 m (RMSE) of the height accuracy of the dataset was confirmed using 5,121 independent check points distributed in the world.
Automatic Test case Generation from UML Activity Diagrams
V.Mary Sumalatha*1; Dr G.S.V.P.Raju2
2014-01-01
Test Case Generation is an important phase in software development. Nowadays much of the research is done on UML diagrams for generating test cases. Activity diagrams are different from flow diagrams in the fact that activity diagrams express parallel behavior which flow diagrams cannot express. This paper concentrates on UML 2.0 Activity Diagram for generating test cases. Fork and join pair in activity diagram are used to represent concurrent activities. A novel method is pro...
AUTOMATIC BIOMASS BOILER WITH AN EXTERNAL THERMOELECTRIC GENERATOR
Marian Brázdil; Ladislav Šnajdárek; Petr Kracík; Jirí Pospíšil
2014-01-01
This paper presents the design and test results of an external thermoelectric generator that utilizes the waste heat from a small-scale domestic biomass boiler with nominal rated heat output of 25 kW. The low-temperature Bi2Te3 generator based on thermoelectric modules has the potential to recover waste heat from gas combustion products as effective energy. The small-scale generator is constructed from independent segments. Measurements have shown that up to 11 W of electricity can be generat...
Chan, William M.; Akien, Edwin (Technical Monitor)
2002-01-01
For many years, generation of overset grids for complex configurations has required the use of a number of different independently developed software utilities. Results created by each step were then visualized using a separate visualization tool before moving on to the next. A new software tool called OVERGRID was developed which allows the user to perform all the grid generation steps and visualization under one environment. OVERGRID provides grid diagnostic functions such as surface tangent and normal checks as well as grid manipulation functions such as extraction, extrapolation, concatenation, redistribution, smoothing, and projection. Moreover, it also contains hyperbolic surface and volume grid generation modules that are specifically suited for overset grid generation. It is the first time that such a unified interface existed for the creation of overset grids for complex geometries. New concepts on automatic overset surface grid generation around surface discontinuities will also be briefly presented. Special control curves on the surface such as intersection curves, sharp edges, open boundaries, are called seam curves. The seam curves are first automatically extracted from a multiple panel network description of the surface. Points where three or more seam curves meet are automatically identified and are called seam corners. Seam corner surface grids are automatically generated using a singular axis topology. Hyperbolic surface grids are then grown from the seam curves that are automatically trimmed away from the seam corners.
International Nuclear Information System (INIS)
BOT3P consists of a set of standard Fortran 77 language programs that gives the users of the deterministic transport codes DORT, TORT, TWODANT, THREEDANT, PARTISN and the sensitivity code SUSD3D some useful diagnostic tools to prepare and check the geometry of their input data files for both Cartesian and cylindrical geometries, including graphical display modules. Users can produce the geometrical and material distribution data for all the cited codes for both two-dimensional and three-dimensional applications and, only in 3-dimensional Cartesian geometry, for the Monte Carlo Transport Code MCNP, starting from the same BOT3P input. Moreover, BOT3P stores the fine mesh arrays and the material zone map in a binary file, the content of which can be easily interfaced to any deterministic and Monte Carlo transport code. This makes it possible to compare directly for the same geometry the effects stemming from the use of different data libraries and solution approaches on transport analysis results. BOT3P Version 5.0 lets users optionally and with the desired precision compute the area/volume error of material zones with respect to the theoretical values, if any, because of the stair-cased representation of the geometry, and automatically update material densities on the whole zone domains to conserve masses. A local (per mesh) density correction approach is also available. BOT3P is designed to run on Linux/UNIX platforms and is publicly available from the Organization for Economic Cooperation and Development (OECD/NEA)/Nuclear Energy Agency Data Bank. Through the use of BOT3P, radiation transport problems with complex 3-dimensional geometrical structures can be modelled easily, as a relatively small amount of engineer-time is required and refinement is achieved by changing few parameters. This tool is useful for solving very large challenging problems, as successfully demonstrated not only in some complex neutron shielding and criticality benchmarks but also in a power
Finite element speaker-specific face model generation for the study of speech production.
Bucki, Marek; Nazari, Mohammad Ali; Payan, Yohan
2010-01-01
International audience In situations where automatic mesh generation is unsuitable, the finite element (FE) mesh registration technique known as mesh-match-and-repair (MMRep) is an interesting option for quickly creating a subject-specific FE model by fitting a predefined template mesh onto the target organ. The irregular or poor quality elements produced by the elastic deformation are corrected by a 'mesh reparation' procedure ensuring that the desired regularity and quality standards are...
Towards a Pattern-based Automatic Generation of Logical Specifications for Software Models
Klimek, Radoslaw
2014-01-01
The work relates to the automatic generation of logical specifications, considered as sets of temporal logic formulas, extracted directly from developed software models. The extraction process is based on the assumption that the whole developed model is structured using only predefined workflow patterns. A method of automatic transformation of workflow patterns to logical specifications is proposed. Applying the presented concepts enables bridging the gap between the benefits of deductive rea...
Validating EHR documents: automatic schematron generation using archetypes.
Pfeiffer, Klaus; Duftschmid, Georg; Rinner, Christoph
2014-01-01
The goal of this study was to examine whether Schematron schemas can be generated from archetypes. The openEHR Java reference API was used to transform an archetype into an object model, which was then extended with context elements. The model was processed and the constraints were transformed into corresponding Schematron assertions. A prototype of the generator for the reference model HL7 v3 CDA R2 was developed and successfully tested. Preconditions for its reusability with other reference models were set. Our results indicate that an automated generation of Schematron schemas is possible with some limitations. PMID:24825691
Medical Image Processing for Fully Integrated Subject Specific Whole Brain Mesh Generation
Chih-Yang Hsu; Ben Schneller; Mahsa Ghaffari; Ali Alaraj; Andreas Linninger
2015-01-01
Currently, anatomically consistent segmentation of vascular trees acquired with magnetic resonance imaging requires the use of multiple image processing steps, which, in turn, depend on manual intervention. In effect, segmentation of vascular trees from medical images is time consuming and error prone due to the tortuous geometry and weak signal in small blood vessels. To overcome errors and accelerate the image processing time, we introduce an automatic image processing pipeline for construc...
On the Support of Multimedia Applications over Wireless Mesh Networks
Directory of Open Access Journals (Sweden)
Chemseddine BEMMOUSSAT
2013-05-01
Full Text Available For next generation wireless networks, supporting quality of service (QoS in multimedia application likevideo, streaming and voice over IP is a necessary and critical requirement. Wireless Mesh Networking isenvisioned as a solution for next networks generation and a promising technology for supportingmultimedia application.With decreasing the numbers of mesh clients, QoS will increase automatically. Several research arefocused to improve QoS in Wireless Mesh networks (WMNs, they try to improve a basics algorithm, likerouting protocols or one of example of canal access, but in moments it no sufficient to ensure a robustsolution to transport multimedia application over WMNs.In this paper we propose an efficient routing algorithm for multimedia transmission in the mesh networkand an approach of QoS in the MAC layer for facilitated transport video over the network studied.
Impact of automatic threshold capture on pulse generator longevity
Institute of Scientific and Technical Information of China (English)
CHEN Ruo-han; CHEN Ke-ping; WANG Fang-zheng; HUA Wei; ZHANG Shu
2006-01-01
Background The automatic, threshold tracking, pacing algorithm developed by St. Jude Medical, verifies ventricular capture beat by beat by recognizing the evoked response following each pacemaker stimulus. This function was assumed to be not only energy saving but safe. This study estimated the extension in longevity obtained by AutoCapture (AC) compared with pacemakers programmed to manually optimized, nominal output.Methods Thirty-four patients who received the St. Jude Affinity series pacemaker were included in the study.The following measurements were taken: stimulation and sensing threshold, impedance of leads, evoked response and polarization signals by 3501 programmer during followup, battery current and battery impedance under different conditions. For longevity comparison, ventricular output was programmed under three different conditions: (1) AC on; (2) AC off with nominal output, and (3) AC off with pacing output set at twice the pacing threshold with a minimum of 2.0 V. Patients were divided into two groups: chronic threshold is higher or lower than 1 V. The efficacy of AC was evaluated.Results Current drain in the AC on group, AC off with optimized programming or nominal output was (14.33±2.84) mA, (16.74±2.75) mA and (18.4±2.44) mA, respectively (AC on or AC off with optimized programming vs. nominal output, P ＜ 0.01). Estimated longevity was significantly extended by AC on when compared with nominal setting [(103 ± 27) months, (80 ± 24) months, P ＜ 0.01). Furthermore, compared with the optimized programming, AC extends the longevity when the pacing threshold is higher than 1 V.Conclusion AC could significantly prolong pacemaker longevity; especially in the patient with high pacing threshold.
Power generation using an activated carbon and metal mesh cathode in a microbial fuel cell
Zhang, Fang
2009-11-01
An inexpensive activated carbon (AC) air cathode was developed as an alternative to a platinum-catalyzed electrode for oxygen reduction in a microbial fuel cell (MFC). AC was cold-pressed with a polytetrafluoroethylene (PTFE) binder to form the cathode around a Ni mesh current collector. This cathode construction avoided the need for carbon cloth or a metal catalyst, and produced a cathode with high activity for oxygen reduction at typical MFC current densities. Tests with the AC cathode produced a maximum power density of 1220 mW/m2 (normalized to cathode projected surface area; 36 W/m3 based on liquid volume) compared to 1060 mW/m2 obtained by Pt catalyzed carbon cloth cathode. The Coulombic efficiency ranged from 15% to 55%. These findings show that AC is a cost-effective material for achieving useful rates of oxygen reduction in air cathode MFCs. © 2009 Elsevier B.V. All rights reserved.
Shoreline and Bathymetry Approximation in Mesh Generation for Tidal Renewable Simulations
Avdis, Alexandros; Hill, Jon; Piggott, Matthew D; Gorman, Gerard J
2015-01-01
Due to the fractal nature of the domain geometry in geophysical flow simulations, a completely accurate description of the domain in terms of a computational mesh is frequently deemed infeasible. Shoreline and bathymetry simplification methods are used to remove small scale details in the geometry, particularly in areas away from the region of interest. To that end, a novel method for shoreline and bathymetry simplification is presented. Existing shoreline simplification methods typically remove points if the resultant geometry satisfies particular geometric criteria. Bathymetry is usually simplified using traditional filtering techniques, that remove unwanted Fourier modes. Principal Component Analysis (PCA) has been used in other fields to isolate small-scale structures from larger scale coherent features in a robust way, underpinned by a rigorous but simple mathematical framework. Here we present a method based on principal component analysis aimed towards simplification of shorelines and bathymetry. We pr...
AN ALGORITHM FOR AUTOMATICALLY GENERATING BLACK-BOX TEST CASES
Institute of Scientific and Technical Information of China (English)
Xu Baowen; Nie Changhai; Shi Qunfeng; Lu Hong
2003-01-01
Selection of test cases plays a key role in improving testing efficiency. Black-box testing is an important way of testing, and its validity lies on the selection of test cases in some sense. A reasonable and effective method about the selection and generation of test cases is urgently needed. This letter first introduces some usualmethods on black-box test case generation,then proposes a new algorithm based on interface parameters and discusses its properties, finally shows the effectiveness of the algorithm.
AN ALGORITHM FOR AUTOMATICALLY GENERATING BLACK－BOX TEST CASES
Institute of Scientific and Technical Information of China (English)
XuBaowen; NieChanghai; 等
2003-01-01
Selection of test cases plays a key role in improving testing efficiency.Black-box testing is an important way of testing,and is validity lies on the secection of test cases in some sense.A reasonable and effective method about the selection and generation of test cascs is urgently needed.This letter first introduces some usual methods on black-box test case generation,then proposes a new glgorithm based on interface parameters and discusses its properties,finally shows the effectiveness of the algorithm.
Intermediate leak protection/automatic shutdown for B and W helical coil steam generator
International Nuclear Information System (INIS)
The report summarizes a follow-on study to the multi-tiered Intermediate Leak/Automatic Shutdown System report. It makes the automatic shutdown system specific to the Babcock and Wilcox (B and W) helical coil steam generator and to the Large Development LMFBR Plant. Threshold leak criteria specific to this steam generator design are developed, and performance predictions are presented for a multi-tier intermediate leak, automatic shutdown system applied to this unit. Preliminary performance predictions for application to the helical coil steam generator were given in the referenced report; for the most part, these predictions have been confirmed. The importance of including a cover gas hydrogen meter in this unit is demonstrated by calculation of a response time one-fifth that of an in-sodium meter at hot standby and refueling conditions
Automatic Generation of Audio Content for Open Learning Resources
Brasher, Andrew; McAndrew, Patrick
2009-01-01
This paper describes how digital talking books (DTBs) with embedded functionality for learners can be generated from content structured according to the OU OpenLearn schema. It includes examples showing how a software transformation developed from open source components can be used to remix OpenLearn content, and discusses issues concerning the…
Automatic generation of computable implementation guides from clinical information models.
Boscá, Diego; Maldonado, José Alberto; Moner, David; Robles, Montserrat
2015-06-01
Clinical information models are increasingly used to describe the contents of Electronic Health Records. Implementation guides are a common specification mechanism used to define such models. They contain, among other reference materials, all the constraints and rules that clinical information must obey. However, these implementation guides typically are oriented to human-readability, and thus cannot be processed by computers. As a consequence, they must be reinterpreted and transformed manually into an executable language such as Schematron or Object Constraint Language (OCL). This task can be difficult and error prone due to the big gap between both representations. The challenge is to develop a methodology for the specification of implementation guides in such a way that humans can read and understand easily and at the same time can be processed by computers. In this paper, we propose and describe a novel methodology that uses archetypes as basis for generation of implementation guides. We use archetypes to generate formal rules expressed in Natural Rule Language (NRL) and other reference materials usually included in implementation guides such as sample XML instances. We also generate Schematron rules from NRL rules to be used for the validation of data instances. We have implemented these methods in LinkEHR, an archetype editing platform, and exemplify our approach by generating NRL rules and implementation guides from EN ISO 13606, openEHR, and HL7 CDA archetypes. PMID:25910958
Automatic generation of min-weighted persistent formations
Institute of Scientific and Technical Information of China (English)
Luo Xiao-Yuan; Li Shao-Bao; Guan Xin-Ping
2009-01-01
This paper researched into some methods for generating min-weighted rigid graphs and min-weighted persistent graphs.Rigidity and persistence are currently used in various studies on coordination and control of autonomous multi-agent formations.To minimize the communication complexity of formations and reduce energy consumption,this paper introduces the rigidity matrix and presents three algorithms for generating min-weighted rigid and min weighted persistent graphs.First,the existence of a min-weighted rigid graph is proved by using the rigidity matrix,and algorithm 1 is presented to generate the min-weighted rigid graphs.Second,the algorithm 2 based on the rigidity matrix is presented to direct the edges of min-weighted rigid graphs to generate min-weighted persistent graphs.Third,the formations with range constraints are considered,and algorithm 3 is presented to find whether a framework can form a min-weighted persistent formation.Finally,some simulations are given to show the efficiency of our research.
Use of design pattern layout for automatic metrology recipe generation
Tabery, Cyrus; Page, Lorena
2005-05-01
As critical dimension control requirements become more challenging, due to complex designs, aggressive lithography, and the constant need to shrink,metrology recipe generation and design evaluation have also become very complex. Hundreds of unique sites must be measured and monitored to ensure good device performance and high yield. The use of the design and layout for automated metrology recipe generation will be critical to that challenge. The DesignGauge from Hitachi implements a system enabling arbitrary recipe generation and control of SEM observations performed on the wafer, based only on the design information. This concept for recipe generation can reduce the time to develop a technology node from RET and design rule selection, through OPC model calibration and verification, and all the way to high volume manufacturing. Conventional recipe creation for a large number of measurement targets requires a significant amount of engineering time. Often these recipes are used only once or twice during mask and process verification or OPC calibration data acquisition. This process of manual setup and analysis is also potentially error prone. CD-SEM recipe creation typically requires an actual wafer, so the recipe creation cannot occur until the scanner and reticle are in house. All of these problems with conventional CD SEM lead to increased development time and reduced final process quality. The new model of CD-SEM recipe generation and management utilizes design-to-SEM matching technology. This new technology extracts an idealized shape from the designed pattern, and utilizes the shape information for pattern matching. As a result, the designed pattern is used as basis for the template instead of the actual SEM image. Recipe creation can be achieved in a matter of seconds once the target site list is finalized. The sequence of steps for creating a recipe are: generate a target site list, pass the design polygons (GDS) and site list to the CD SEM, define references
Automatic generation of indoor navigation instructions for blind users using a user-centric graph.
Dong, Hao; Ganz, Aura
2014-01-01
The complexity and diversity of indoor environments brings significant challenges to automatic generation of navigation instructions for blind and visually impaired users. Unlike generation of navigation instructions for robots, we need to take into account the blind users wayfinding ability. In this paper we introduce a user-centric graph based solution for cane users that takes into account the blind users cognitive ability as well as the user's mobility patterns. We introduce the principles of generating the graph and the algorithm used to automatically generate the navigation instructions using this graph. We successfully tested the efficiency of the instruction generation algorithm, the correctness of the generated paths, and the quality of the navigation instructions. Blindfolded sighted users were successful in navigating through a three-story building. PMID:25570105
Semantic annotation of requirements for automatic UML class diagram generation
Directory of Open Access Journals (Sweden)
Soumaya Amdouni
2011-05-01
Full Text Available The increasing complexity of software engineering requires effective methods and tools to support requirements analysts' activities. While much of a company's knowledge can be found in text repositories, current content management systems have limited capabilities for structuring and interpreting documents. In this context, we propose a tool for transforming text documents describing users' requirements to an UML model. The presented tool uses Natural Language Processing (NLP and semantic rules to generate an UML class diagram. The main contribution of our tool is to provide assistance to designers facilitating the transition from a textual description of user requirements to their UML diagrams based on GATE (General Architecture of Text by formulating necessary rules that generate new semantic annotations.
VOX POPULI: automatic generation of biased video sequences
Bocconi, S; Nack, Frank
2004-01-01
We describe our experimental rhetoric engine Vox Populi that generates biased video-sequences from a repository of video interviews and other related audio-visual web sources. Users are thus able to explore their own opinions on controversial topics covered by the repository. The repository contains interviews with United States residents stating their opinion on the events occurring after the terrorist attack on the United States on the 11th of September 2001. We present a model for biased d...
Automatic Generation of Correlation Rules to Detect Complex Attack Scenarios
Godefroy, Erwan; Totel, Eric; Hurfin, Michel; Majorczyk, Frédéric
2014-01-01
In large distributed information systems, alert correlation systems are necessary to handle the huge amount of elementary security alerts and to identify complex multi-step attacks within the flow of low level events and alerts. In this paper, we show that, once a human expert has provided an action tree derived from an attack tree, a fully automated transformation process can generate exhaustive correlation rules that would be tedious and error prone to enumerate by hand. The transformation ...
FAsTA: A Folksonomy-Based Automatic Metadata Generator
Al-Khalifa, Hend S.; Davis, Hugh C.
2007-01-01
Folksonomies provide a free source of keywords describing web resources, however, these keywords are free form and unstructured. In this paper, we describe a novel tool that converts folksonomy tags into semantic metadata, and present a case study consisting of a framework for evaluating the usefulness of this metadata within the context of a particular eLearning application. The evaluation shows the number of ways in which the generated semantic metadata adds value to the raw folksonomy tags.
A hybrid approach to automatic generation of NC programs
G. Payeganeh; M. Tolouei-Rad
2005-01-01
Purpose: This paper describes AGNCP, an intelligent system for integrating commercial CAD and CAM systems for 2.5D milling operations at a low cost.Design/methodology/approach: It deals with different machining problems with the aid of two expert systems. It recognizes machining features, determines required machining process plans, cutting tools and parameters necessary for generation of NC programs.Findings: The system deals with different machining problems with the aid of two expert syste...
Using DSL for Automatic Generation of Software Connectors
Czech Academy of Sciences Publication Activity Database
Bureš, Tomáš; Malohlava, M.; Hnětynka, P.
Los Alamitos: IEEE Computer Society, 2008, s. 138-147. ISBN 978-0-7695-3091-8. [ICCBSS 2008. International Conference on Composition-Based Software Systems /7./. Madrid (ES), 25.02.2008-29.02.2008,] R&D Projects: GA AV ČR 1ET400300504 Institutional research plan: CEZ:AV0Z10300504 Keywords : component based systems * software connectors * code generation * domain-specific languages Subject RIV: JC - Computer Hardware ; Software
VOX POPULI: Automatic Generation of Biased Video Sequences
Bocconi, S.; Nack, Frank
2004-01-01
We describe our experimental rhetoric engine Vox Populi that generates biased video-sequences from a repository of video interviews and other related audio-visual web sources. Users are thus able to explore their own opinions on controversial topics covered by the repository. The repository contains interviews with United States residents stating their opinion on the events occurring after the terrorist attack on the United States on the 11th of September 2001. We present a model for biased d...
Research and implementation of report automatic generation measure based on perl CGI
International Nuclear Information System (INIS)
The running process is usually accompanied with a large number of data about operation states in the large scale real time data processing system, and the data should be managed through out some performance report by operation engineers. A solution for performance report automatic generation is presented. It is to build a performance report automatic generation system by extracting the massages of the database and UNIX file system and deploying it to an application system. The system has been applied at the CTBT NDC. (authors)
Automatic Geometry Generation from Point Clouds for BIM
Charles Thomson; Jan Boehm
2015-01-01
The need for better 3D documentation of the built environment has come to the fore in recent years, led primarily by city modelling at the large scale and Building Information Modelling (BIM) at the smaller scale. Automation is seen as desirable as it removes the time-consuming and therefore costly amount of human intervention in the process of model generation. BIM is the focus of this paper as not only is there a commercial need, as will be shown by the number of commercial solutions, but a...
Automatic Generation of Network Protocol Gateways
DEFF Research Database (Denmark)
Bromberg, Yérom-David; Réveillère, Laurent; Lawall, Julia;
2009-01-01
, however, requires an intimate knowledge of the relevant protocols and a substantial understanding of low-level network programming, which can be a challenge for many application programmers. This paper presents a generative approach to gateway construction, z2z, based on a domain-specific language......The emergence of networked devices in the home has made it possible to develop applications that control a variety of household functions. However, current devices communicate via a multitude of incompatible protocols, and thus gateways are needed to translate between them. Gateway construction...
Automatic Geometry Generation from Point Clouds for BIM
Directory of Open Access Journals (Sweden)
Charles Thomson
2015-09-01
Full Text Available The need for better 3D documentation of the built environment has come to the fore in recent years, led primarily by city modelling at the large scale and Building Information Modelling (BIM at the smaller scale. Automation is seen as desirable as it removes the time-consuming and therefore costly amount of human intervention in the process of model generation. BIM is the focus of this paper as not only is there a commercial need, as will be shown by the number of commercial solutions, but also wide research interest due to the aspiration of automated 3D models from both Geomatics and Computer Science communities. The aim is to go beyond the current labour-intensive tracing of the point cloud to an automated process that produces geometry that is both open and more verifiable. This work investigates what can be achieved today with automation through both literature review and by proposing a novel point cloud processing process. We present an automated workflow for the generation of BIM data from 3D point clouds. We also present quality indicators for reconstructed geometry elements and a framework in which to assess the quality of the reconstructed geometry against a reference.
Automatic generation of synchronization instructions for parallel processors
Energy Technology Data Exchange (ETDEWEB)
Midkiff, S.P.
1986-05-01
The development of high speed parallel multi-processors, capable of parallel execution of doacross and forall loops, has stimulated the development of compilers to transform serial FORTRAN programs to parallel forms. One of the duties of such a compiler must be to place synchronization instructions in the parallel version of the program to insure the legal execution order of doacross and forall loops. This thesis gives strategies usable by a compiler to generate these synchronization instructions. It presents algorithms for reducing the parallelism in FORTRAN programs to match a target architecture, recovering some of the parallelism so discarded, and reducing the number of synchronization instructions that must be added to a FORTRAN program, as well as basic strategies for placing synchronization instructions. These algorithms are developed for two synchronization instruction sets. 20 refs., 56 figs.
Automatic generation of Feynman rules in the Schroedinger functional
Energy Technology Data Exchange (ETDEWEB)
Takeda, Shinji [Humboldt Universitaet zu Berlin, Newtonstr. 15, 12489 Berlin (Germany)], E-mail: takeda@physik.hu-berlin.de
2009-04-11
We provide an algorithm to generate vertices for the Schroedinger functional with an abelian background gauge field. The background field has a non-trivial color structure, therefore we mainly focus on a manipulation of the color matrix part. We propose how to implement the algorithm especially in python code. By using python outputs produced by the code, we also show how to write a numerical expression of vertices in the time-momentum as well as the coordinate space into a Feynman diagram calculation code. As examples of the applications of the algorithm, we provide some one-loop results, ratios of the {lambda} parameters between the plaquette gauge action and the improved gauge actions composed from six-link loops (rectangular, chair and parallelogram), the determination of the O(a) boundary counter term to this order, and the perturbative cutoff effects of the step scaling function of the Schroedinger functional coupling constant.
Modular code supervisor. Automatic generation of command language
International Nuclear Information System (INIS)
It is shown how, starting from a problem formulated by the user, to generate the adequate calculation procedure in the command code, and acquire the data necessary for the calculation while verifying their validity. Modular codes are used, because of their flexibility and wide utilisation. Modules are written in Fortran, and calculations are done in batches according to an algorithm written in the GIBIANE command language. The action plans are based on the STRIPS and WARPLAN families. Elementary representation of a module and special instructions are illustrated. Dynamic construction macro-actions, and acquisition of the specification (which allows users to express the goal of a program without indicating which algorithm is used to reach the goal) are illustrated. The final phase consists in translating the algorithm into the command language
Contribution of supraspinal systems to generation of automatic postural responses
Directory of Open Access Journals (Sweden)
Tatiana G Deliagina
2014-10-01
Full Text Available Different species maintain a particular body orientation in space due to activity of the closed-loop postural control system. In this review we discuss the role of neurons of descending pathways in operation of this system as revealed in animal models of differing complexity: lower vertebrate (lamprey and higher vertebrates (rabbit and cat.In the lamprey and quadruped mammals, the role of spinal and supraspinal mechanisms in the control of posture is different. In the lamprey, the system contains one closed-loop mechanism consisting of supraspino-spinal networks. Reticulospinal (RS neurons play a key role in generation of postural corrections. Due to vestibular input, any deviation from the stabilized body orientation leads to activation of a specific population of RS neurons. Each of the neurons activates a specific motor synergy. Collectively, these neurons evoke the motor output necessary for the postural correction. In contrast to lampreys, postural corrections in quadrupeds are primarily based not on the vestibular input but on the somatosensory input from limb mechanoreceptors. The system contains two closed-loop mechanisms – spinal and spino-supraspinal networks, which supplement each other. Spinal networks receive somatosensory input from the limb signaling postural perturbations, and generate spinal postural limb reflexes. These reflexes are relatively weak, but in intact animals they are enhanced due to both tonic supraspinal drive and phasic supraspinal commands. Recent studies of these supraspinal influences are considered in this review. A hypothesis suggesting common principles of operation of the postural systems stabilizing body orientation in a particular plane in the lamprey and quadrupeds, that is interaction of antagonistic postural reflexes, is discussed.
Automatic Generation of Printed Catalogs: An Initial Attempt
Directory of Open Access Journals (Sweden)
Jared Camins-Esakov
2010-06-01
Full Text Available Printed catalogs are useful in a variety of contexts. In special collections, they are often used as reference tools and to commemorate exhibits. They are useful in settings, such as in developing countries, where reliable access to the Internet—or even electricity—is not available. In addition, many private collectors like to have printed catalogs of their collections. All the information needed for creating printed catalogs is readily available in the MARC bibliographic records used by most libraries, but there are no turnkey solutions available for the conversion from MARC to printed catalog. This article describes the development of a system, available on github, that uses XSLT, Perl, and LaTeX to produce press-ready PDFs from MARCXML files. The article particularly focuses on the two XSLT stylesheets which comprise the core of the system, and do the "heavy lifting" of sorting and indexing the entries in the catalog. The author also highlights points where the data stored in MARC bibliographic records requires particular "massaging," and suggests improvements for future attempts at automated printed catalog generation.
A hybrid approach to automatic generation of NC programs
Directory of Open Access Journals (Sweden)
G. Payeganeh
2005-12-01
Full Text Available Purpose: This paper describes AGNCP, an intelligent system for integrating commercial CAD and CAM systems for 2.5D milling operations at a low cost.Design/methodology/approach: It deals with different machining problems with the aid of two expert systems. It recognizes machining features, determines required machining process plans, cutting tools and parameters necessary for generation of NC programs.Findings: The system deals with different machining problems with the aid of two expert systems. The first communicates with CAD system for recognizing machining features. It is developed in LISP as machining features can be properly represented by LISP codes is ideal for manipulating lists and input data. The second expert system requires extensive communications with several databases for retrieving tooling and machining information and VP-Expert shell was found to be the most suitable package to perform this task.Research limitations/implications: 2.5D milling covers a wide range of operations. However, work is in progress cover 3D milling operations. The system can also be modified to be used for other activities such as turning, flame cutting, electro discharge machining (EDM, punching, etc.Practical implications: Use of AGNCP resulted in improved efficiency, noticeable time savings, and elimination of the need for expert process planners.Originality/value: The paper describes a method for eliminating the need for extensive user intervention for CAD/CAM integration.
INGRID, 3-D Mesh Generator for Program DYNA3D and NIKE3D and FACET and TOPAZ3D
International Nuclear Information System (INIS)
1 - Description of program or function: INGRID is a general-purpose, three-dimensional mesh generator developed for use with finite element, nonlinear, structural dynamics codes. INGRID generates the large and complex input data files for DYNA3D (NESC 9909), NIKE3D (NESC 9725), FACET, and TOPAZ3D. One of the greatest advantages of INGRID is that virtually any shape can be described without resorting to wedge elements, tetrahedrons, triangular elements or highly distorted quadrilateral or hexahedral elements. Other capabilities available are in the areas of geometry and graphics. Exact surface equations and surface intersections considerably improve the ability to deal with accurate models, and a hidden line graphics algorithm is included which is efficient on the most complicated meshes. The most important new capability is associated with the boundary conditions, loads, and material properties required by nonlinear mechanics programs. Commands have been designed for each case to minimize user effort. This is particularly important since special processing is almost always required for each load or boundary condition. 2 - Method of solution: Geometries are described primarily using the index space notation of the INGEN program (NESC 975) with an additional type of notation, index progression. Index progressions provide a concise and simple method for describing complex structures; the concept was developed to facilitate defining multiple regions in index space. Rather than specifying the minimum and maximum indices for a region, one specifies the progression of indices along the I, J and K directions, respectively. The index progression method allows the analyst to describe most geometries including nodes and elements with roughly the same amount of input as a solids modeler
International Nuclear Information System (INIS)
Improving speed and quality of Eddy Current non-destructive testing of steam generator tubes leads to automation of all process that contribute to diagnosis. This paper describes how signal processing, pattern recognition and artificial and artificial intelligence are used to build a software package that is able to automatically provide an efficient diagnosis. (author)
Using Automatic Code Generation in the Attitude Control Flight Software Engineering Process
McComas, David; O'Donnell, James R., Jr.; Andrews, Stephen F.
1999-01-01
This paper presents an overview of the attitude control subsystem flight software development process, identifies how the process has changed due to automatic code generation, analyzes each software development phase in detail, and concludes with a summary of our lessons learned.
Bayerlein, Leopold
2014-01-01
This study assesses whether or not undergraduate and postgraduate accounting students at an Australian university differentiate between timely feedback and extremely timely feedback, and whether or not the replacement of manually written formal assessment feedback with automatically generated feedback influences students' perception of…
Planet-disc interaction on a freely moving mesh
Munoz, Diego J; Springel, Volker; Hernquist, Lars
2014-01-01
General-purpose, moving-mesh schemes for hydrodynamics have opened the possibility of combining the accuracy of grid-based numerical methods with the flexibility and automatic resolution adaptivity of particle-based methods. Due to their supersonic nature, Keplerian accretion discs are in principle a very attractive system for applying such freely moving mesh techniques. However, the high degree of symmetry of simple accretion disc models can be difficult to capture accurately by these methods, due to the generation of geometric grid noise and associated numerical diffusion, which is absent in polar grids. To explore these and other issues, in this work we study the idealized problem of two-dimensional planet-disc interaction with the moving-mesh code AREPO. We explore the hydrodynamic evolution of discs with planets through a series of numerical experiments that vary the planet mass, the disc viscosity and the mesh resolution, and compare the resulting surface density, vortensity field and tidal torque with ...
Directory of Open Access Journals (Sweden)
A. Suresh Babu
2012-03-01
Full Text Available In this paper, analysis of automatic generation control (AGC using integral controller is carried out in the deregulated environment. The traditional AGC of two area system is modified and implemented inderegulated environment to account the effect of contracted and un-contracted power demands on system dynamics. The concept of DISCO participation matrix (DPM to simulate bilateral contracts is proposed. Gain setting of integral controller is optimized without considering Generation Rate Constraint (GRC using Integral Squared Error (ISE technique.
Revisiting the Steam-Boiler Case Study with LUTESS : Modeling for Automatic Test Generation
Papailiopoulou, Virginia; Seljimi, Besnik; Parissis, Ioannis
2009-01-01
International audience LUTESS is a testing tool for synchronous software making possible to automatically build test data generators. The latter rely on a formal model of the program environment composed of a set of invariant properties, supposed to hold for every software execution. Additional assumptions can be used to guide the test data generation. The environment descriptions together with the assumptions correspond to a test model of the program. In this paper, we apply this modeling...
Accuracy assessment of building point clouds automatically generated from iphone images
Sirmacek, B.; Lindenbergh, R.
2014-06-01
Low-cost sensor generated 3D models can be useful for quick 3D urban model updating, yet the quality of the models is questionable. In this article, we evaluate the reliability of an automatic point cloud generation method using multi-view iPhone images or an iPhone video file as an input. We register such automatically generated point cloud on a TLS point cloud of the same object to discuss accuracy, advantages and limitations of the iPhone generated point clouds. For the chosen example showcase, we have classified 1.23% of the iPhone point cloud points as outliers, and calculated the mean of the point to point distances to the TLS point cloud as 0.11 m. Since a TLS point cloud might also include measurement errors and noise, we computed local noise values for the point clouds from both sources. Mean (μ) and standard deviation (σ) of roughness histograms are calculated as (μ1 = 0.44 m., σ1 = 0.071 m.) and (μ2 = 0.025 m., σ2 = 0.037 m.) for the iPhone and TLS point clouds respectively. Our experimental results indicate possible usage of the proposed automatic 3D model generation framework for 3D urban map updating, fusion and detail enhancing, quick and real-time change detection purposes. However, further insights should be obtained first on the circumstances that are needed to guarantee a successful point cloud generation from smartphone images.
Evaluation of Semi-Automatic Metadata Generation Tools: A Survey of the Current State of the Art
Park, Jung-ran; Brenza, Andrew
2015-01-01
Assessment of the current landscape of semi-automatic metadata generation tools is particularly important considering the rapid development of digital repositories and the recent explosion of big data. Utilization of (semi)automatic metadata generation is critical in addressing these environmental changes and may be unavoidable in the future considering the costly and complex operation of manual metadata creation. To address such needs, this study examines the range of semi-automatic metadata...
Li, Zhigang; Han, Xiaoqiang; Ge, Hao; Ma, Chunsheng
2016-07-01
To account for the effects of head realistic morphological feature variation on the impact dynamic responses to head injury, it is necessary to develop multiple subject-specific pediatric head finite element (FE) models based on computed tomography (CT) or magnetic resonance imaging (MRI) scans. However, traditional manual model development is very time-consuming. In this study, a new automatic method was developed to extract anatomical points from pediatric head CT scans to represent pediatric head morphological features (head size/shape, skull thickness, and suture/fontanel width). Subsequently, a geometry-adaptive mesh morphing method based on radial basis function was developed that can automatically morph a baseline pediatric head FE model into target FE models with geometries corresponding to the extracted head morphological features. In the end, five subject-specific head FE models of approximately 6-month-old (6MO) were automatically generated using the developed method. These validated models were employed to investigate differences in the head dynamic responses among subjects with different head morphologies. The results show that variations in head morphological features have a relatively large effect on pediatric head dynamic response. The results of this study indicate that pediatric head morphological variation had better be taken into account when reconstructing pediatric head injury due to traffic/fall accidents or child abuses using computational models as well as predicting head injury risk for children with obvious difference in head size and morphologies. PMID:27058003
Hwang, Taejin; Kim, Yong Nam; Kim, Soo Kon; Kang, Sei-Kwon; Cheong, Kwang-Ho; Park, Soah; Yoon, Jai-Woong; Han, Taejin; Kim, Haeyoung; Lee, Meyeon; Kim, Kyoung-Joo; Bae, Hoonsik; Suh, Tae-Suk
2015-06-01
The dose constraint during prostate intensity-modulated radiation therapy (IMRT) optimization should be patient-specific for better rectum sparing. The aims of this study are to suggest a novel method for automatically generating a patient-specific dose constraint by using an experience-based dose volume histogram (DVH) of the rectum and to evaluate the potential of such a dose constraint qualitatively. The normal tissue complication probabilities (NTCPs) of the rectum with respect to V %ratio in our study were divided into three groups, where V %ratio was defined as the percent ratio of the rectal volume overlapping the planning target volume (PTV) to the rectal volume: (1) the rectal NTCPs in the previous study (clinical data), (2) those statistically generated by using the standard normal distribution (calculated data), and (3) those generated by combining the calculated data and the clinical data (mixed data). In the calculated data, a random number whose mean value was on the fitted curve described in the clinical data and whose standard deviation was 1% was generated by using the `randn' function in the MATLAB program and was used. For each group, we validated whether the probability density function (PDF) of the rectal NTCP could be automatically generated with the density estimation method by using a Gaussian kernel. The results revealed that the rectal NTCP probability increased in proportion to V %ratio , that the predictive rectal NTCP was patient-specific, and that the starting point of IMRT optimization for the given patient might be different. The PDF of the rectal NTCP was obtained automatically for each group except that the smoothness of the probability distribution increased with increasing number of data and with increasing window width. We showed that during the prostate IMRT optimization, the patient-specific dose constraints could be automatically generated and that our method could reduce the IMRT optimization time as well as maintain the
Final Report for LDRD Project on Rapid Problem Setup for Mesh-Based Simulation (Rapsodi)
Energy Technology Data Exchange (ETDEWEB)
Brown, D L; Henshaw, W; Petersson, N A; Fast, P; Chand, K
2003-02-07
Under LLNL Exploratory Research LDRD funding, the Rapsodi project developed rapid setup technology for computational physics and engineering problems that require computational representations of complex geometry. Many simulation projects at LLNL involve the solution of partial differential equations in complex 3-D geometries. A significant bottleneck in carrying out these simulations arises in converting some specification of a geometry, such as a computer-aided design (CAD) drawing to a computationally appropriate 3-D mesh that can be used for simulation and analysis. Even using state-of-the-art mesh generation software, this problem setup step typically has required weeks or months, which is often much longer than required to carry out the computational simulation itself. The Rapsodi project built computational tools and designed algorithms that help to significantly reduce this setup time to less than a day for many realistic problems. The project targeted rapid setup technology for computational physics and engineering problems that use mixed-element unstructured meshes, overset meshes or Cartesian-embedded boundary (EB) meshes to represent complex geometry. It also built tools that aid in constructing computational representations of geometry for problems that do not require a mesh. While completely automatic mesh generation is extremely difficult, the amount of manual labor required can be significantly reduced. By developing novel, automated, component-based mesh construction procedures and automated CAD geometry repair and cleanup tools, Rapsodi has significantly reduced the amount of hand crafting required to generate geometry and meshes for scientific simulation codes.
Automatic WSDL-guided Test Case Generation for PropEr Testing of Web Services
Directory of Open Access Journals (Sweden)
Konstantinos Sagonas
2012-10-01
Full Text Available With web services already being key ingredients of modern web systems, automatic and easy-to-use but at the same time powerful and expressive testing frameworks for web services are increasingly important. Our work aims at fully automatic testing of web services: ideally the user only specifies properties that the web service is expected to satisfy, in the form of input-output relations, and the system handles all the rest. In this paper we present in detail the component which lies at the heart of this system: how the WSDL specification of a web service is used to automatically create test case generators that can be fed to PropEr, a property-based testing tool, to create structurally valid random test cases for its operations and check its responses. Although the process is fully automatic, our tool optionally allows the user to easily modify its output to either add semantic information to the generators or write properties that test for more involved functionality of the web services.
Efficient Packet Forwarding in Mesh Network
Kanrar, Soumen
2012-01-01
Wireless Mesh Network (WMN) is a multi hop low cost, with easy maintenance robust network providing reliable service coverage. WMNs consist of mesh routers and mesh clients. In this architecture, while static mesh routers form the wireless backbone, mesh clients access the network through mesh routers as well as directly meshing with each other. Different from traditional wireless networks, WMN is dynamically self-organized and self-configured. In other words, the nodes in the mesh network automatically establish and maintain network connectivity. Over the years researchers have worked, to reduce the redundancy in broadcasting packet in the mesh network in the wireless domain for providing reliable service coverage, the source node deserves to broadcast or flood the control packets. The redundant control packet consumes the bandwidth of the wireless medium and significantly reduces the average throughput and consequently reduces the overall system performance. In this paper I study the optimization problem in...
Automatic feature template generation for maximum entropy based intonational phrase break prediction
Zhou, You
2013-03-01
The prediction of intonational phrase (IP) breaks is important for both the naturalness and intelligibility of Text-to- Speech (TTS) systems. In this paper, we propose a maximum entropy (ME) model to predict IP breaks from unrestricted text, and evaluate various keyword selection approaches in different domains. Furthermore, we design a hierarchical clustering algorithm for automatic generation of feature templates, which minimizes the need for human supervision during ME model training. Results of comparative experiments show that, for the task of IP break prediction, ME model obviously outperforms classification and regression tree (CART), log-likelihood ratio is the best scoring measure of keyword selection, compared with manual templates, templates automatically generated by our approach greatly improves the F-score of ME based IP break prediction, and significantly reduces the size of ME model.
HIGH QUALITY IMPLEMENTATION FOR AUTOMATIC GENERATION C# CODE BY EVENT-B PATTERN
Directory of Open Access Journals (Sweden)
Eman K Elsayed
2014-01-01
Full Text Available In this paper we proposed the logical correct path to implement automatically any algorithm or model in verified C# code. Our proposal depends on using the event-B as a formal method. It is suitable solution for un-experience in programming language and profession in mathematical modeling. Our proposal also integrates requirements, codes and verification in system development life cycle. We suggest also using event-B pattern. Our suggestion is classify into two cases, the algorithm case and the model case. The benefits of our proposal are reducing the prove effort, reusability, increasing the automation degree and generate high quality code. In this paper we applied and discussed the three phases of automatic code generation philosophy on two case studies the first is “minimum algorithm” and the second one is a model for ATM.
Automatic Generation of Deep Web Wrappers based on Discovery of Repetition
Nakatoh, Tetsuya; Yamada, Yasuhiro; Hirokawa, Sachio
2004-01-01
A Deep Web wrapper is a program that extracts contents from search results. We propose a new automatic wrapper generation algorithm which discovers a repetitive pattern from search results. The repetitive pattern is expressed by token sequences which consist of HTML tags, plain texts and wild-cards. The algorithm applies a string matching with mismatches to unify the variation from the template and uses FFT(fast Fourier transformation) to attain efficiency. We show an empirical evaluation of ...
Luo Hanwu; Li Mengke; Xu Xinyao; Cui Shigang; Han Yin; Yan Kai; Wang Jing; Le Jian
2016-01-01
This paper presents a novel method to solve the initial lightning breakdown current by combing ATP and MATLAB simulation software effectively, with the aims to evaluate the lightning protection performance of transmission line. Firstly, the executable ATP simulation model is generated automatically according to the required information such as power source parameters, tower parameters, overhead line parameters, grounding resistance and lightning current parameters, etc. through an interface p...
Sunnåker, Mikael; Zamora-Sillero, Elias; Dechant, Reinhard; Ludwig, Christina; Busetto, Alberto Giovanni; Wagner, Andreas; Stelling, Joerg
2013-01-01
Predictive dynamical models are critical for the analysis of complex biological systems. However, methods to systematically develop and discriminate among systems biology models are still lacking. Here, we describe a computational method that incorporates all hypothetical mechanisms about the architecture of a biological system into a single model, and automatically generates a set of simpler models compatible with observational data. As a proof-of-principle, we analyzed the dynamic control o...
Deriving Safety Cases for the Formal Safety Certification of Automatically Generated Code
Basir, Nurlida; Denney, Ewen; Fischer, Bernd
2008-01-01
We present an approach to systematically derive safety cases for automatically generated code from information collected during a formal, Hoare-style safety certification of the code. This safety case makes explicit the formal and informal reasoning principles, and reveals the top-level assumptions and external dependencies that must be taken into account; however, the evidence still comes from the formal safety proofs. It uses a generic goal-based argument that is instantiated with respect t...
An integrated automatic system for the eddy-current testing of the steam generator tubes
Energy Technology Data Exchange (ETDEWEB)
Woo, Hee Gon; Choi, Seong Su [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center
1995-12-31
This research project was focused on automation of steam generator tubes inspection for nuclear power plants. ECT (Eddy Current Testing) inspection process in nuclear power plants is classified into 3 subprocesses such as signal acquisition process, signal evaluation process, and inspection planning and data management process. Having been automated individually, these processes were effectively integrated into an automatic inspection system, which was implemented in HP workstation with expert system developed (author). 25 refs., 80 figs.
Fully automatic adjoints: a robust and efficient mechanism for generating adjoint ocean models
Ham, D. A.; Farrell, P. E.; Funke, S. W.; Rognes, M. E.
2012-04-01
The problem of generating and maintaining adjoint models is sufficiently difficult that typically only the most advanced and well-resourced community ocean models achieve it. There are two current technologies which each suffer from their own limitations. Algorithmic differentiation, also called automatic differentiation, is employed by models such as the MITGCM [2] and the Alfred Wegener Institute model FESOM [3]. This technique is very difficult to apply to existing code, and requires a major initial investment to prepare the code for automatic adjoint generation. AD tools may also have difficulty with code employing modern software constructs such as derived data types. An alternative is to formulate the adjoint differential equation and to discretise this separately. This approach, known as the continuous adjoint and employed in ROMS [4], has the disadvantage that two different model code bases must be maintained and manually kept synchronised as the model develops. The discretisation of the continuous adjoint is not automatically consistent with that of the forward model, producing an additional source of error. The alternative presented here is to formulate the flow model in the high level language UFL (Unified Form Language) and to automatically generate the model using the software of the FEniCS project. In this approach it is the high level code specification which is differentiated, a task very similar to the formulation of the continuous adjoint [5]. However since the forward and adjoint models are generated automatically, the difficulty of maintaining them vanishes and the software engineering process is therefore robust. The scheduling and execution of the adjoint model, including the application of an appropriate checkpointing strategy is managed by libadjoint [1]. In contrast to the conventional algorithmic differentiation description of a model as a series of primitive mathematical operations, libadjoint employs a new abstraction of the simulation
Unidirectional high fiber content composites: Automatic 3D FE model generation and damage simulation
DEFF Research Database (Denmark)
Qing, Hai; Mishnaevsky, Leon
2009-01-01
A new method and a software code for the automatic generation of 3D micromechanical FE models of unidirectional long-fiber-reinforced composite (LFRC) with high fiber volume fraction with random fiber arrangement are presented. The fiber arrangement in the cross-section is generated through random...... movements of fibers from their initial regular hexagonal arrangement. Damageable layers are introduced into the fibers to take into account the random distribution of the fiber strengths. A series of computational experiments on the glass fibers reinforced polymer epoxy matrix composite is performed to...
Automatic generation of stop word lists for information retrieval and analysis
Rose, Stuart J
2013-01-08
Methods and systems for automatically generating lists of stop words for information retrieval and analysis. Generation of the stop words can include providing a corpus of documents and a plurality of keywords. From the corpus of documents, a term list of all terms is constructed and both a keyword adjacency frequency and a keyword frequency are determined. If a ratio of the keyword adjacency frequency to the keyword frequency for a particular term on the term list is less than a predetermined value, then that term is excluded from the term list. The resulting term list is truncated based on predetermined criteria to form a stop word list.
AUTOMATIC GENERATION CONTROL OF MULTI AREA POWER SYSTEMS USING ANN CONTROLLER
Directory of Open Access Journals (Sweden)
Bipasha Bhatia
2012-07-01
Full Text Available This paper presents the use of one of the methods of artificial intelligence to study the automatic generation control of interconnected power systems. In the given paper, a control line of track is established for interconnected three area thermal-thermal-thermal power system using generation rate constraints (GRC &Artificial Neural Network (ANN. The working of the controllers is simulated using MATLAB/SIMULINK package. The outputs using both controllers are compared and it is established that ANN based approach is better than GRC for 1% step load conditions.
ModelMage: a tool for automatic model generation, selection and management.
Flöttmann, Max; Schaber, Jörg; Hoops, Stephan; Klipp, Edda; Mendes, Pedro
2008-01-01
Mathematical modeling of biological systems usually involves implementing, simulating, and discriminating several candidate models that represent alternative hypotheses. Generating and managing these candidate models is a tedious and difficult task and can easily lead to errors. ModelMage is a tool that facilitates management of candidate models. It is designed for the easy and rapid development, generation, simulation, and discrimination of candidate models. The main idea of the program is to automatically create a defined set of model alternatives from a single master model. The user provides only one SBML-model and a set of directives from which the candidate models are created by leaving out species, modifiers or reactions. After generating models the software can automatically fit all these models to the data and provides a ranking for model selection, in case data is available. In contrast to other model generation programs, ModelMage aims at generating only a limited set of models that the user can precisely define. ModelMage uses COPASI as a simulation and optimization engine. Thus, all simulation and optimization features of COPASI are readily incorporated. ModelMage can be downloaded from http://sysbio.molgen.mpg.de/modelmage and is distributed as free software. PMID:19425122
On Optimal Bilinear Quadrilateral Meshes
Energy Technology Data Exchange (ETDEWEB)
D' Azevedo, E.
1998-10-26
The novelty of this work is in presenting interesting error properties of two types of asymptotically optimal quadrilateral meshes for bilinear approximation. The first type of mesh has an error equidistributing property where the maximum interpolation error is asymptotically the same over all elements. The second type has faster than expected super-convergence property for certain saddle-shaped data functions. The super-convergent mesh may be an order of magnitude more accurate than the error equidistributing mesh. Both types of mesh are generated by a coordinate transformation of a regular mesh of squares. The coordinate transformation is derived by interpreting the Hessian matrix of a data function as a metric tensor. The insights in this work may have application in mesh design near known corner or point singularities.
On Optimal Bilinear Quadrilateral Meshes
Energy Technology Data Exchange (ETDEWEB)
D' Azevedo, E
2000-03-17
The novelty of this work is in presenting interesting error properties of two types of asymptotically ''optimal'' quadrilateral meshes for bilinear approximation. The first type of mesh has an error equidistributing property where the maximum interpolation error is asymptotically the same over all elements. The second type has faster than expected ''super-convergence'' property for certain saddle-shaped data functions. The ''superconvergent'' mesh may be an order of magnitude more accurate than the error equidistributing mesh. Both types of mesh are generated by a coordinate transformation of a regular mesh of squares. The coordinate transformation is derived by interpreting the Hessian matrix of a data function as a metric tensor. The insights in this work may have application in mesh design near corner or point singularities.
Automatic Generation of Data Types for Classification of Deep Web Sources
Energy Technology Data Exchange (ETDEWEB)
Ngu, A H; Buttler, D J; Critchlow, T J
2005-02-14
A Service Class Description (SCD) is an effective meta-data based approach for discovering Deep Web sources whose data exhibit some regular patterns. However, it is tedious and error prone to create an SCD description manually. Moreover, a manually created SCD is not adaptive to the frequent changes of Web sources. It requires its creator to identify all the possible input and output types of a service a priori. In many domains, it is impossible to exhaustively list all the possible input and output data types of a source in advance. In this paper, we describe machine learning approaches for automatic generation of the data types of an SCD. We propose two different approaches for learning data types of a class of Web sources. The Brute-Force Learner is able to generate data types that can achieve high recall, but with low precision. The Clustering-based Learner generates data types that have a high precision rate, but with a lower recall rate. We demonstrate the feasibility of these two learning-based solutions for automatic generation of data types for citation Web sources and presented a quantitative evaluation of these two solutions.
Directory of Open Access Journals (Sweden)
Preeti Hooda,
2014-06-01
Full Text Available The load-frequency control (LFC is used to restore the balance between load and generation in each control area by means of speed control. In power system, the main goal of load frequency control (LFC or automatic generation control (AGC is to maintain the frequency of each area and tie- line power flow within specified tolerance by adjusting the MW outputs of LFC generators so as to accommodate fluctuating load demands. In this paper, attempt is made to make a scheme for automatic generation control within a restructured environment considering effects of contracts between DISCOs and GENCOs to make power system network in normal state where, GENCO used are hydro plants as well as thermal plants. The bacterial foraging optimization technique is being developed, which is applied to AGC in an interconnected four area system.The performance of the system is obtained by MATLAB Simulink tool. The results are shown in frequency and power response for four area AGC system. In this paper we have shown practical work by using thermal and hydro both system at Genco’s side.As reheated system transfer function is being used.
Energy Technology Data Exchange (ETDEWEB)
Chavez, Patrick F.
2006-03-01
The CABLEGEN C++ program has been developed to automate the process of developing a CUBIT journal file for coaxial cables with and without air gap defects. This program is part of the coaxial cable design simulator that is currently under development.
Notes on the Mesh Handler and Mesh Data Conversion
International Nuclear Information System (INIS)
At the outset of the development of the thermal-hydraulic code (THC), efforts have been made to utilize the recent technology of the computational fluid dynamics. Among many of them, the unstructured mesh approach was adopted to alleviate the restriction of the grid handling system. As a natural consequence, a mesh handler (MH) has been developed to manipulate the complex mesh data from the mesh generator. The mesh generator, Gambit, was chosen at the beginning of the development of the code. But a new mesh generator, Pointwise, was introduced to get more flexible mesh generation capability. An open source code, Paraview, was chosen as a post processor, which can handle unstructured as well as structured mesh data. Overall data processing system for THC is shown in Figure-1. There are various file formats to save the mesh data in the permanent storage media. A couple of dozen of file formats are found even in the above mentioned programs. A competent mesh handler should have the capability to import or export mesh data as many as possible formats. But, in reality, there are two aspects that make it difficult to achieve the competence. The first aspect to consider is the time and efforts to program the interface code. And the second aspect, which is even more difficult one, is the fact that many mesh data file formats are proprietary information. In this paper, some experience of the development of the format conversion programs will be presented. File formats involved are Gambit neutral format, Ansys-CFX grid file format, VTK legacy file format, Nastran format and CGNS
An Automatic K-Point Grid Generation Scheme for Enhanced Efficiency and Accuracy in DFT Calculations
Mohr, Jennifer A.-F.; Shepherd, James J.; Alavi, Ali
2013-03-01
We seek to create an automatic k-point grid generation scheme for density functional theory (DFT) calculations that improves the efficiency and accuracy of the calculations and is suitable for use in high-throughput computations. Current automated k-point generation schemes often result in calculations with insufficient k-points, which reduces the reliability of the results, or too many k-points, which can significantly increase computational cost. By controlling a wider range of k-point grid densities for the Brillouin zone based upon factors of conductivity and symmetry, a scalable k-point grid generation scheme can lower calculation runtimes and improve the accuracy of energy convergence. Johns Hopkins University
Energy Technology Data Exchange (ETDEWEB)
Krishnan, Venkat; Das, Trishna
2016-05-01
Increasing variable generation penetration and the consequent increase in short-term variability makes energy storage technologies look attractive, especially in the ancillary market for providing frequency regulation services. This paper presents slow dynamics model for compressed air energy storage and battery storage technologies that can be used in automatic generation control studies to assess the system frequency response and quantify the benefits from storage technologies in providing regulation service. The paper also represents the slow dynamics model of the power system integrated with storage technologies in a complete state space form. The storage technologies have been integrated to the IEEE 24 bus system with single area, and a comparative study of various solution strategies including transmission enhancement and combustion turbine have been performed in terms of generation cycling and frequency response performance metrics.
Directory of Open Access Journals (Sweden)
Luo Hanwu
2016-01-01
Full Text Available This paper presents a novel method to solve the initial lightning breakdown current by combing ATP and MATLAB simulation software effectively, with the aims to evaluate the lightning protection performance of transmission line. Firstly, the executable ATP simulation model is generated automatically according to the required information such as power source parameters, tower parameters, overhead line parameters, grounding resistance and lightning current parameters, etc. through an interface program coded by MATLAB. Then, the data are extracted from the generated LIS files which can be obtained by executing the ATP simulation model, the occurrence of transmission lie breakdown can be determined by the relative data in LIS file. The lightning current amplitude should be reduced when the breakdown occurs, and vice the verse. Thus the initial lightning breakdown current of a transmission line with given parameters can be determined accurately by continuously changing the lightning current amplitude, which is realized by a loop computing algorithm that is coded by MATLAB software. The method proposed in this paper can generate the ATP simulation program automatically, and facilitates the lightning protection performance assessment of transmission line.
International Nuclear Information System (INIS)
Highlights: → A realistic model for automatic generation control (AGC) design is proposed. → The model considers GRC, Speed governor dead band, filters and time delay. → The model provides an accurate model for the digital simulations. -- Abstract: This paper addresses a realistic model for automatic generation control (AGC) design in an interconnected power system. The proposed scheme considers generation rate constraint (GRC), dead band, and time delay imposed to the power system by governor-turbine, filters, thermodynamic process, and communication channels. Simplicity of structure and acceptable response of the well-known integral controller make it attractive for the power system AGC design problem. The Genetic algorithm (GA) is used to compute the decentralized control parameters to achieve an optimum operating point. A 3-control area power system is considered as a test system, and the closed-loop performance is examined in the presence of various constraints scenarios. It is shown that neglecting above physical constraints simultaneously or in part, leads to impractical and invalid results and may affect the system security, reliability and integrity. Taking to account the advantages of GA besides considering a more complete dynamic model provides a flexible and more realistic AGC system in comparison of existing conventional schemes.
Energy Technology Data Exchange (ETDEWEB)
Golpira, H., E-mail: hemin.golpira@uok.ac.i [Department of Electrical and Computer Engineering, University of Kurdistan, Sanandaj, PO Box 416, Kurdistan (Iran, Islamic Republic of); Bevrani, H. [Department of Electrical and Computer Engineering, University of Kurdistan, Sanandaj, PO Box 416, Kurdistan (Iran, Islamic Republic of); Golpira, H. [Department of Industrial Engineering, Islamic Azad University, Sanandaj Branch, PO Box 618, Kurdistan (Iran, Islamic Republic of)
2011-05-15
Highlights: {yields} A realistic model for automatic generation control (AGC) design is proposed. {yields} The model considers GRC, Speed governor dead band, filters and time delay. {yields} The model provides an accurate model for the digital simulations. -- Abstract: This paper addresses a realistic model for automatic generation control (AGC) design in an interconnected power system. The proposed scheme considers generation rate constraint (GRC), dead band, and time delay imposed to the power system by governor-turbine, filters, thermodynamic process, and communication channels. Simplicity of structure and acceptable response of the well-known integral controller make it attractive for the power system AGC design problem. The Genetic algorithm (GA) is used to compute the decentralized control parameters to achieve an optimum operating point. A 3-control area power system is considered as a test system, and the closed-loop performance is examined in the presence of various constraints scenarios. It is shown that neglecting above physical constraints simultaneously or in part, leads to impractical and invalid results and may affect the system security, reliability and integrity. Taking to account the advantages of GA besides considering a more complete dynamic model provides a flexible and more realistic AGC system in comparison of existing conventional schemes.
Reliable Mining of Automatically Generated Test Cases from Software Requirements Specification (SRS)
Raamesh, Lilly
2010-01-01
Writing requirements is a two-way process. In this paper we use to classify Functional Requirements (FR) and Non Functional Requirements (NFR) statements from Software Requirements Specification (SRS) documents. This is systematically transformed into state charts considering all relevant information. The current paper outlines how test cases can be automatically generated from these state charts. The application of the states yields the different test cases as solutions to a planning problem. The test cases can be used for automated or manual software testing on system level. And also the paper presents a method for reduction of test suite by using mining methods thereby facilitating the mining and knowledge extraction from test cases.
Automatic Generation of Mashups for Personalized Commerce in Digital TV by Semantic Reasoning
Blanco-Fernández, Yolanda; López-Nores, Martín; Pazos-Arias, José J.; Martín-Vicente, Manuela I.
The evolution of information technologies is consolidating recommender systems as essential tools in e-commerce. To date, these systems have focused on discovering the items that best match the preferences, interests and needs of individual users, to end up listing those items by decreasing relevance in some menus. In this paper, we propose extending the current scope of recommender systems to better support trading activities, by automatically generating interactive applications that provide the users with personalized commercial functionalities related to the selected items. We explore this idea in the context of Digital TV advertising, with a system that brings together semantic reasoning techniques and new architectural solutions for web services and mashups.
Automatic Data Extraction from Websites for Generating Aquatic Product Market Information
Institute of Scientific and Technical Information of China (English)
YUAN Hong-chun; CHEN Ying; SUN Yue-fu
2006-01-01
The massive web-based information resources have led to an increasing demand for effective automatic retrieval of target information for web applications. This paper introduces a web-based data extraction tool that deploys various algorithms to locate, extract and filter tabular data from HTML pages and to transform them into new web-based representations. The tool has been applied in an aquaculture web application platform for extracting and generating aquatic product market information.Results prove that this tool is very effective in extracting the required data from web pages.
Design and construction of a graphical interface for automatic generation of simulation code GEANT4
International Nuclear Information System (INIS)
This work is set in the context of the engineering studies final project; it is accomplished in the center of nuclear sciences and technologies in Sidi Thabet. This project is about conceiving and developing a system based on graphical user interface which allows an automatic codes generation for simulation under the GEANT4 engine. This system aims to facilitate the use of GEANT4 by scientific not necessary expert in this engine and to be used in different areas: research, industry and education. The implementation of this project uses Root library and several programming languages such as XML and XSL. (Author). 5 refs
Method of modifying a volume mesh using sheet extraction
Borden, Michael J.; Shepherd, Jason F.
2007-02-20
A method and machine-readable medium provide a technique to modify a hexahedral finite element volume mesh using dual generation and sheet extraction. After generating a dual of a volume stack (mesh), a predetermined algorithm may be followed to modify the volume mesh of hexahedral elements. The predetermined algorithm may include the steps of determining a sheet of hexahedral mesh elements, generating nodes for merging, and merging the nodes to delete the sheet of hexahedral mesh elements and modify the volume mesh.
Automatic Generation of Human-like Route Descriptions: A Corpus-driven Approach
Directory of Open Access Journals (Sweden)
Rafael Teles
2013-11-01
Full Text Available Most of Web applications combines differents services, features and contents in order to enable the creation of new features and services. Such systems are called mashups. One of the most popular kind of mashups are the location ones that use geographic data to provide functionalites to users. The RotaCerta is a location system that uses the Google Maps and perform Natural Language Generation to provide textual descriptions of routes between two different locations. The great advantage of RotaCerta is the use of points of interest (POI to describe routes. POIs help the user to understand and assimilate the route. However, RotaCerta suffers from a several limitation: the need for manualy updating of a POIs dataset. Such work is exhausting, costly and greatly limits their use. Another point to highlight is the poor linguistic variability of texts it provides. In this work, we propose a mechanism to enable automatic feeding of POIs and a corpus-driven approach to enhance the linguistic variability of location mashups such as RotaCerta.We adopt both manual and automatic generation of new textual templates. In order to assess the quality of the routes descriptions, we use TF-IDF and cosine distance to calculate the similarity between descriptions of routes created by human volunteers and descriptions generated by the proposed approach. Route generation examples have been performed for three different brazilian cities. We also show that the text generated from the new template base is more similar to the texts used by people when describing routes if compared to Google Maps.
Directory of Open Access Journals (Sweden)
Qi Chen
2014-12-01
Full Text Available Intelligent seamline selection for image mosaicking is an area of active research in the fields of massive data processing, computer vision, photogrammetry and remote sensing. In mosaicking applications for digital orthophoto maps (DOMs, the visual transition in mosaics is mainly caused by differences in positioning accuracy, image tone and relief displacement of high ground objects between overlapping DOMs. Among these three factors, relief displacement, which prevents the seamless mosaicking of images, is relatively more difficult to address. To minimize visual discontinuities, many optimization algorithms have been studied for the automatic selection of seamlines to avoid high ground objects. Thus, a new automatic seamline selection algorithm using a digital surface model (DSM is proposed. The main idea of this algorithm is to guide a seamline toward a low area on the basis of the elevation information in a DSM. Given that the elevation of a DSM is not completely synchronous with a DOM, a new model, called the orthoimage elevation synchronous model (OESM, is derived and introduced. OESM can accurately reflect the elevation information for each DOM unit. Through the morphological processing of the OESM data in the overlapping area, an initial path network is obtained for seamline selection. Subsequently, a cost function is defined on the basis of several measurements, and Dijkstra’s algorithm is adopted to determine the least-cost path from the initial network. Finally, the proposed algorithm is employed for automatic seamline network construction; the effective mosaic polygon of each image is determined, and a seamless mosaic is generated. The experiments with three different datasets indicate that the proposed method meets the requirements for seamline network construction. In comparative trials, the generated seamlines pass through fewer ground objects with low time consumption.
User Manual for the PROTEUS Mesh Tools
Energy Technology Data Exchange (ETDEWEB)
Smith, Micheal A. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, Emily R. [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-06-01
This report describes the various mesh tools that are provided with the PROTEUS code giving both descriptions of the input and output. In many cases the examples are provided with a regression test of the mesh tools. The most important mesh tools for any user to consider using are the MT_MeshToMesh.x and the MT_RadialLattice.x codes. The former allows the conversion between most mesh types handled by PROTEUS while the second allows the merging of multiple (assembly) meshes into a radial structured grid. Note that the mesh generation process is recursive in nature and that each input specific for a given mesh tool (such as .axial or .merge) can be used as “mesh” input for any of the mesh tools discussed in this manual.
User Manual for the PROTEUS Mesh Tools
International Nuclear Information System (INIS)
This report describes the various mesh tools that are provided with the PROTEUS code giving both descriptions of the input and output. In many cases the examples are provided with a regression test of the mesh tools. The most important mesh tools for any user to consider using are the MTMeshToMesh.x and the MTRadialLattice.x codes. The former allows the conversion between most mesh types handled by PROTEUS while the second allows the merging of multiple (assembly) meshes into a radial structured grid. Note that the mesh generation process is recursive in nature and that each input specific for a given mesh tool (such as .axial or .merge) can be used as ''mesh'' input for any of the mesh tools discussed in this manual.
Semi-Automatic Mapping Generation for the DBpedia Information Extraction Framework
Directory of Open Access Journals (Sweden)
Arup Sarkar, Ujjal Marjit, Utpal Biswas
2013-03-01
Full Text Available DBpedia is one of the very well known live projectsfrom the Semantic Web. It is likeamirror version ofthe Wikipedia site in Semantic Web. Initially itpublishes the information collected from theWikipedia, but only that part which is relevant tothe Semantic Web.Collecting information forSemantic Web from the Wikipedia is demonstratedas the extraction of structured data. DBpedianormally do this by using a specially designedframework called DBpedia Information ExtractionFramework. This extraction framework do itsworks thorough the evaluation of the similarproperties from the DBpedia Ontology and theWikipedia template. This step is known as DBpediamapping.At present mostof the mapping jobs aredone complete manually.In this paper a newframework is introduced considering the issuesrelated to the template to ontology mapping. A semi-automatic mapping tool for the DBpedia projectisproposedwith the capability of automaticsuggestion generation for the end usersso thatusers can identify the similar Ontology and templateproperties.Proposed framework is useful since afterselection of similar properties, the necessary code tomaintain the mapping between Ontology andtemplate is generated automatically.
Automatic Generation Control in Multi Area Interconnected Power System by using HVDC Links
Directory of Open Access Journals (Sweden)
Yogendra Arya
2012-01-01
Full Text Available This paper investigates the effects of HVDC link in parallel with HVAC link on automatic generation control (AGC problem for a multi-area power system taking into consideration system parameter variations. A fuzzy logic controller is proposed for four area power system interconnected via parallel HVAC/HVDC transmission link which is also referred as asynchronous tie-lines. The linear model of HVAC/HVDC link is developed and the system responses to sudden load change are studied. The simulation studies are carried out for a four area interconnected thermal power system. Suitable solution for automatic generation control problem of four area electrical power system is obtained by means of improving the dynamic performance of power system under study. Robustness of controller is also checked by varying parameters. Simulation results indicate that the scheme works well. The dynamic analyses have been done with and without HVDC link using fuzzy logic controller in Matlab-Simulink. Further a comparison between the two is presented and it has been shown that the performance of the proposed scheme is superior in terms of overshoot and settling time.
Quadrilateral mesh fitting that preserves sharp features based on multi-normals for Laplacian energy
Directory of Open Access Journals (Sweden)
Yusuke Imai
2014-04-01
Full Text Available Because the cost of performance testing using actual products is expensive, manufacturers use lower-cost computer-aided design simulations for this function. In this paper, we propose using hexahedral meshes, which are more accurate than tetrahedral meshes, for finite element analysis. We propose automatic hexahedral mesh generation with sharp features to precisely represent the corresponding features of a target shape. Our hexahedral mesh is generated using a voxel-based algorithm. In our previous works, we fit the surface of the voxels to the target surface using Laplacian energy minimization. We used normal vectors in the fitting to preserve sharp features. However, this method could not represent concave sharp features precisely. In this proposal, we improve our previous Laplacian energy minimization by adding a term that depends on multi-normal vectors instead of using normal vectors. Furthermore, we accentuate a convex/concave surface subset to represent concave sharp features.
GRACE/SUSY Automatic Generation of Tree Amplitudes in the Minimal Supersymmetric Standard Model
Fujimoto, J
2003-01-01
GRACE/SUSY is a program package for generating the tree-level amplitude and evaluating the corresponding cross section of processes of the minimal supersymmetric extension of the standard model (MSSM). The Higgs potential adopted in the system, however, is assumed to have a more general form indicated by the two-Higgs-doublet model. This system is an extension of GRACE for the standard model(SM) of the electroweak and strong interactions. For a given MSSM process the Feynman graphs and amplitudes at tree-level are automatically created. The Monte-Carlo phase space integration by means of BASES gives the total and differential cross sections. When combined with SPRING, an event generator, the program package provides us with the simulation of the SUSY particle productions.
Hybrid Chaotic Particle Swarm Optimization Based Gains For Deregulated Automatic Generation Control
Directory of Open Access Journals (Sweden)
Cheshta Jain Dr. H. K. Verma
2011-12-01
Full Text Available Generation control is an important objective of power system operation. In modern power system, the traditional automatic generation control (AGC is modified by incorporating the effect of bilateral contracts. This paper investigates application of chaotic particle swarm optimization (CPSO for optimized operation of restructured AGC system. To obtain optimum gains of controllers, application of adaptive inertia weight factor and constriction factors is proposed to improve performance of particle swarm optimization (PSO algorithm. It is also observed that chaos mapping using logistic map sequence increases convergence rate of traditional PSO algorithm. The hybrid method presented in this paper gives global optimum gains of controller with significant improvement in convergence rate over basic PSO algorithm. The effectiveness and efficiency of the proposed algorithm have been tested on two area restructure system.
Differential Evolution for Optimization of PID Gains in Automatic Generation Control
Directory of Open Access Journals (Sweden)
Dr. L.D. Arya,
2011-05-01
Full Text Available Automatic generation control (AGC of a multi area power system provides power demand signals for AGC power generators to control frequency and tie-line power flow due to the large load changes or other disturbances. Occurrence of large megawatt imbalance causes large frequency deviations from its nominal value which may be a threat to secure operation of power system. To avoid such situation,emergency control to maintain the system frequency using differential evolution (DE based proportionalintegral- derivative (PID controller is proposed in this paper. DE is one of the most powerful stochastic real parameter optimization in current use. DE based optimum gains give better optimal transient response of frequency and tie line power changes compared to particle swarm optimization based gains.
Automatic deodorizing system for waste water from radioisotope facilities using an ozone generator
International Nuclear Information System (INIS)
We applied an ozone generator to sterilize and to deodorize the waste water from radioisotope facilities. A small tank connected to the generator is placed outside of the drainage facility founded previously, not to oxidize the other apparatus. The waste water is drained 1 m3 at a time from the tank of drainage facility, treated with ozone and discharged to sewer. All steps proceed automatically once the draining work is started remotely in the office. The waste water was examined after the ozone treatment for 0 (original), 0.5, 1.0, 1.5 and 2.0 h. Regarding original waste water, the sum of coliform groups varied with every examination repeated - probably depend on the colibacilli used in experiments; hydrogen sulfide, biochemical oxygen demand and the offensive odor increased with increasing coliform groups. The ozone treatment remarkably decreased hydrogen sulfide and the offensive odor, decreased coliform groups when the original water had rich coliforms. (author)
Punzalan, Florencio Rusty; Kunieda, Yoshitoshi; Amano, Akira
2015-01-01
Clinical and experimental studies involving human hearts can have certain limitations. Methods such as computer simulations can be an important alternative or supplemental tool. Physiological simulation at the tissue or organ level typically involves the handling of partial differential equations (PDEs). Boundary conditions and distributed parameters, such as those used in pharmacokinetics simulation, add to the complexity of the PDE solution. These factors can tailor PDE solutions and their corresponding program code to specific problems. Boundary condition and parameter changes in the customized code are usually prone to errors and time-consuming. We propose a general approach for handling PDEs and boundary conditions in computational models using a replacement scheme for discretization. This study is an extension of a program generator that we introduced in a previous publication. The program generator can generate code for multi-cell simulations of cardiac electrophysiology. Improvements to the system allow it to handle simultaneous equations in the biological function model as well as implicit PDE numerical schemes. The replacement scheme involves substituting all partial differential terms with numerical solution equations. Once the model and boundary equations are discretized with the numerical solution scheme, instances of the equations are generated to undergo dependency analysis. The result of the dependency analysis is then used to generate the program code. The resulting program code are in Java or C programming language. To validate the automatic handling of boundary conditions in the program code generator, we generated simulation code using the FHN, Luo-Rudy 1, and Hund-Rudy cell models and run cell-to-cell coupling and action potential propagation simulations. One of the simulations is based on a published experiment and simulation results are compared with the experimental data. We conclude that the proposed program code generator can be used to
AbouEisha, Hassan M.
2014-01-01
In this paper we present a dynamic programming algorithm for finding optimal elimination trees for the multi-frontal direct solver algorithm executed over two dimensional meshes with point singularities. The elimination tree found by the optimization algorithm results in a linear computational cost of sequential direct solver. Based on the optimal elimination tree found by the optimization algorithm we construct heuristic sequential multi-frontal direct solver algorithm resulting in a linear computational cost as well as heuristic parallel multi-frontal direct solver algorithm resulting in a logarithmic computational cost. The resulting parallel algorithm is implemented on NVIDIA CUDA GPU architecture based on our graph-grammar approach. © 2014 Springer-Verlag.
Finite element meshing approached as a global minimization process
Energy Technology Data Exchange (ETDEWEB)
WITKOWSKI,WALTER R.; JUNG,JOSEPH; DOHRMANN,CLARK R.; LEUNG,VITUS J.
2000-03-01
The ability to generate a suitable finite element mesh in an automatic fashion is becoming the key to being able to automate the entire engineering analysis process. However, placing an all-hexahedron mesh in a general three-dimensional body continues to be an elusive goal. The approach investigated in this research is fundamentally different from any other that is known of by the authors. A physical analogy viewpoint is used to formulate the actual meshing problem which constructs a global mathematical description of the problem. The analogy used was that of minimizing the electrical potential of a system charged particles within a charged domain. The particles in the presented analogy represent duals to mesh elements (i.e., quads or hexes). Particle movement is governed by a mathematical functional which accounts for inter-particles repulsive, attractive and alignment forces. This functional is minimized to find the optimal location and orientation of each particle. After the particles are connected a mesh can be easily resolved. The mathematical description for this problem is as easy to formulate in three-dimensions as it is in two- or one-dimensions. The meshing algorithm was developed within CoMeT. It can solve the two-dimensional meshing problem for convex and concave geometries in a purely automated fashion. Investigation of the robustness of the technique has shown a success rate of approximately 99% for the two-dimensional geometries tested. Run times to mesh a 100 element complex geometry were typically in the 10 minute range. Efficiency of the technique is still an issue that needs to be addressed. Performance is an issue that is critical for most engineers generating meshes. It was not for this project. The primary focus of this work was to investigate and evaluate a meshing algorithm/philosophy with efficiency issues being secondary. The algorithm was also extended to mesh three-dimensional geometries. Unfortunately, only simple geometries were tested
Automatic evaluation and data generation for analytical chemistry instrumental analysis exercises
Directory of Open Access Journals (Sweden)
Arsenio Muñoz de la Peña
2014-01-01
Full Text Available In general, laboratory activities are costly in terms of time, space, and money. As such, the ability to provide realistically simulated laboratory data that enables students to practice data analysis techniques as a complementary activity would be expected to reduce these costs while opening up very interesting possibilities. In the present work, a novel methodology is presented for design of analytical chemistry instrumental analysis exercises that can be automatically personalized for each student and the results evaluated immediately. The proposed system provides each student with a different set of experimental data generated randomly while satisfying a set of constraints, rather than using data obtained from actual laboratory work. This allows the instructor to provide students with a set of practical problems to complement their regular laboratory work along with the corresponding feedback provided by the system's automatic evaluation process. To this end, the Goodle Grading Management System (GMS, an innovative web-based educational tool for automating the collection and assessment of practical exercises for engineering and scientific courses, was developed. The proposed methodology takes full advantage of the Goodle GMS fusion code architecture. The design of a particular exercise is provided ad hoc by the instructor and requires basic Matlab knowledge. The system has been employed with satisfactory results in several university courses. To demonstrate the automatic evaluation process, three exercises are presented in detail. The first exercise involves a linear regression analysis of data and the calculation of the quality parameters of an instrumental analysis method. The second and third exercises address two different comparison tests, a comparison test of the mean and a t-paired test.
Automatic generation of 3D motifs for classification of protein binding sites
Directory of Open Access Journals (Sweden)
Herzyk Pawel
2007-08-01
Full Text Available Abstract Background Since many of the new protein structures delivered by high-throughput processes do not have any known function, there is a need for structure-based prediction of protein function. Protein 3D structures can be clustered according to their fold or secondary structures to produce classes of some functional significance. A recent alternative has been to detect specific 3D motifs which are often associated to active sites. Unfortunately, there are very few known 3D motifs, which are usually the result of a manual process, compared to the number of sequential motifs already known. In this paper, we report a method to automatically generate 3D motifs of protein structure binding sites based on consensus atom positions and evaluate it on a set of adenine based ligands. Results Our new approach was validated by generating automatically 3D patterns for the main adenine based ligands, i.e. AMP, ADP and ATP. Out of the 18 detected patterns, only one, the ADP4 pattern, is not associated with well defined structural patterns. Moreover, most of the patterns could be classified as binding site 3D motifs. Literature research revealed that the ADP4 pattern actually corresponds to structural features which show complex evolutionary links between ligases and transferases. Therefore, all of the generated patterns prove to be meaningful. Each pattern was used to query all PDB proteins which bind either purine based or guanine based ligands, in order to evaluate the classification and annotation properties of the pattern. Overall, our 3D patterns matched 31% of proteins with adenine based ligands and 95.5% of them were classified correctly. Conclusion A new metric has been introduced allowing the classification of proteins according to the similarity of atomic environment of binding sites, and a methodology has been developed to automatically produce 3D patterns from that classification. A study of proteins binding adenine based ligands showed that
扫掠法有限元网格生成方法%Algorithm for finite element mesh generation based on sweeping
Institute of Scientific and Technical Information of China (English)
曾卓; 陈家新
2013-01-01
In order to improve the quality of the finite element mesh generation, placement of interior node is a crucial step in the generation of hexahedral meshes using sweeping algorithms. A new algorithm based on sweeping method for hexahedral mesh generation is processed for complex sweep volume. The algorithm uses source surface which has divided good grid and connection of surface structured grid, generates the target surface with affine map projection step by step. It puts forward positioning of the new algorithm based on the internal node Roca algorithm. By the use of wave front inside extroversion of theory, it generates all the hexahedral grid. Example shows that the proposed algorithm is effective, reliable and robust, and it can handle the hexahedral mesh generation problem of a great deal of complex 2.5-dimensional geometries.%为了提高有限元网格的生成质量,扫掠法生成六面体网格过程中内部节点定位成为关键一步,在研究复杂扫掠体六面体有限元网格生成算法过程中,提出了一种基于扫掠法的六面体网格生成算法,算法利用源曲面已经划分好的网格和连接曲面的结构化网格,用仿射映射逐层投影,生成目标曲面,提出基于Roca算法的内部节点定位的新算法,运用由外向内推进的波前法思想,生成全部的六面体网格.通过实例表明,该算法快速,稳定,可靠,可处理大量复杂2.5维实体六面体网格生成问题.
Kim, Kahee; Joung, Hyou-Arm; Han, Gyeo-Re; Kim, Min-Gon
2016-11-15
An immunochromatographic assay (ICA) strip is one of the most widely used platforms in the field of point-of-care biosensors for the detection of various analytes in a simple, fast, and inexpensive manner. Currently, several approaches for sequential reactions in ICA platforms have improved their usability, sensitivity, and versatility. In this study, a new, simple, and low-cost approach using automatic sequential-reaction ICA strip is described. The automatic switching of a reagent pad from separation to attachment to the test membrane was achieved using a water-swellable polymer. The reagent pad was dried with an enzyme substrate for signal generation or with signal-enhancing materials. The strip design and system operation were confirmed by the characterization of the raw materials and flow analysis. We demonstrated the operation of the proposed sensor by using various chemical reaction-based assays, including metal-ion amplification, enzyme-colorimetric reaction, and enzyme-catalyzed chemiluminescence. Furthermore, by employing C-reactive protein as a model, we successfully demonstrated that the new water-swellable polymer-based ICA sensor can be utilized to detect biologically relevant analytes in human serum. PMID:27203463
一种改进的Delaunay三角形化剖分方法%A MODIFIED DELAUNAY MESH GENERATION METHOD FOR 2-D DOMAIN
Institute of Scientific and Technical Information of China (English)
徐明海; 张俨彬; 陶文铨
2001-01-01
提出了一种基于Bowyer-Watson算法的平面区域Delaunay三角化剖分的改进方法。它结合了前沿推进法的内部结点生成技术和Delaunay联点网格生成技术，使得每插入一点所破坏的单元尽可能地少。采用适当的数据结构，使Delaunay搜索过程限于局部，算法大为简化，易于编程，浮点计算量少，同时也避免了使用函数递归调用。采用在基网格上定义网格步长的办法控制网格的疏密，使网格疏密易于控制。几个算例表明，该算法是行之有效的。%A method for constructing two-dimensional unstructured meshes using the Delaunay triangulation criterion is described.The algorithm is based on the Bowyer-Watson's idea to construct the node links and on the advancing front method for generating the inner nodes. In the triangulation process, the latter inserted nodes may break less links by using this method. By taking the edges into the data structure, the Delaunay searching is a local process, and the recursive function calling can be avoided. So it is easy to construct the code, and the floating-point computation is reduced. The mesh density is controlled through defining the mesh step on the vertices of the ground mesh. Some examples show that the algorithm is robust and effective.
Algebraic mesh quality metrics
Energy Technology Data Exchange (ETDEWEB)
KNUPP,PATRICK
2000-04-24
Quality metrics for structured and unstructured mesh generation are placed within an algebraic framework to form a mathematical theory of mesh quality metrics. The theory, based on the Jacobian and related matrices, provides a means of constructing, classifying, and evaluating mesh quality metrics. The Jacobian matrix is factored into geometrically meaningful parts. A nodally-invariant Jacobian matrix can be defined for simplicial elements using a weight matrix derived from the Jacobian matrix of an ideal reference element. Scale and orientation-invariant algebraic mesh quality metrics are defined. the singular value decomposition is used to study relationships between metrics. Equivalence of the element condition number and mean ratio metrics is proved. Condition number is shown to measure the distance of an element to the set of degenerate elements. Algebraic measures for skew, length ratio, shape, volume, and orientation are defined abstractly, with specific examples given. Combined metrics for shape and volume, shape-volume-orientation are algebraically defined and examples of such metrics are given. Algebraic mesh quality metrics are extended to non-simplical elements. A series of numerical tests verify the theoretical properties of the metrics defined.
Directory of Open Access Journals (Sweden)
Adrian ALEXANDRESCU
2008-01-01
Full Text Available This paper contains some ideas concerning the Enterprise Information Systems (EIS development. It combines known elements from the software engineering domain, with original elements, which the author has conceived and experimented. The author has followed two major objectives: to use a simple description for the concepts of an EIS, and to achieve a rapid and reliable EIS development process with minimal cost. The first goal was achieved defining some models, which describes the conceptual elements of the EIS domain: entities, events, actions, states and attribute-domain. The second goal is based on a predefined architectural model for the EIS, on predefined analyze and design models for the elements of the domain and finally on the automatic generation of the system components. The proposed methods do not depend on a special programming language or a data base management system. They are general and may be applied to any combination of such technologies.
Wei, Gongjin; Bai, Weijing; Yin, Meifang; Zhang, Songmao
We present a practice of applying the Semantic Web technologies in the domain of Chinese traditional architecture. A knowledge base consisting of one ontology and four rule bases is built to support the automatic generation of animations that demonstrate the construction of various Chinese timber structures based on the user's input. Different Semantic Web formalisms are used, e.g., OWL DL, SWRL and Jess, to capture the domain knowledge, including the wooden components needed for a given building, construction sequence, and the 3D size and position of every piece of wood. Our experience in exploiting the current Semantic Web technologies in real-world application systems indicates their prominent advantages (such as the reasoning facilities and modeling tools) as well as the limitations (such as low efficiency).
HELAC-Onia: an automatic matrix element generator for heavy quarkonium physics
Shao, Hua-Sheng
2013-01-01
By the virtues of the Dyson-Schwinger equations, we upgrade the published code \\mtt{HELAC} to be capable to calculate the heavy quarkonium helicity amplitudes in the framework of NRQCD factorization, which we dub \\mtt{HELAC-Onia}. We rewrote the original \\mtt{HELAC} to make the new program be able to calculate helicity amplitudes of multi P-wave quarkonium states production at hadron colliders and electron-positron colliders by including new P-wave off-shell currents. Therefore, besides the high efficiencies in computation of multi-leg processes within the Standard Model, \\mtt{HELAC-Onia} is also sufficiently numerical stable in dealing with P-wave quarkonia (e.g. $h_{c,b},\\chi_{c,b}$) and P-wave color-octet intermediate states. To the best of our knowledge, it is a first general-purpose automatic quarkonium matrix elements generator based on recursion relations on the market.
HELAC-Onia: An automatic matrix element generator for heavy quarkonium physics
Shao, Hua-Sheng
2013-11-01
By the virtues of the Dyson-Schwinger equations, we upgrade the published code HELAC to be capable to calculate the heavy quarkonium helicity amplitudes in the framework of NRQCD factorization, which we dub HELAC-Onia. We rewrote the original HELAC to make the new program be able to calculate helicity amplitudes of multi P-wave quarkonium states production at hadron colliders and electron-positron colliders by including new P-wave off-shell currents. Therefore, besides the high efficiencies in computation of multi-leg processes within the Standard Model, HELAC-Onia is also sufficiently numerical stable in dealing with P-wave quarkonia (e.g. h,χ) and P-wave color-octet intermediate states. To the best of our knowledge, it is a first general-purpose automatic quarkonium matrix elements generator based on recursion relations on the market.
Directory of Open Access Journals (Sweden)
Esha Gupta
2016-12-01
Full Text Available This paper presents an application of grey wolf optimizer (GWO in order to find the parameters of primary governor loop for successful Automatic Generation Control of two areas’ interconnected power system. Two standard objective functions, Integral Square Error and Integral Time Absolute Error (ITAE, have been employed to carry out this parameter estimation process. Eigenvalues along with dynamic response analysis reveals that criterion of ITAE yields better performance. The comparison of the regulator performance obtained from GWO is carried out with Genetic Algorithm (GA, Particle Swarm Optimization, and Gravitational Search Algorithm. Different types of perturbations and load changes are incorporated in order to establish the efficacy of the obtained design. It is observed that GWO outperforms all three optimization methods. The optimization performance of GWO is compared with other algorithms on the basis of standard deviations in the values of parameters and objective functions.
Utilizing Linked Open Data Sources for Automatic Generation of Semantic Metadata
Nummiaho, Antti; Vainikainen, Sari; Melin, Magnus
In this paper we present an application that can be used to automatically generate semantic metadata for tags given as simple keywords. The application that we have implemented in Java programming language creates the semantic metadata by linking the tags to concepts in different semantic knowledge bases (CrunchBase, DBpedia, Freebase, KOKO, Opencyc, Umbel and/or WordNet). The steps that our application takes in doing so include detecting possible languages, finding spelling suggestions and finding meanings from amongst the proper nouns and common nouns separately. Currently, our application supports English, Finnish and Swedish words, but other languages could be included easily if the required lexical tools (spellcheckers, etc.) are available. The created semantic metadata can be of great use in, e.g., finding and combining similar contents, creating recommendations and targeting advertisements.
Automatic fuzzy rule generation and its application to the navigation control for mobile robot
International Nuclear Information System (INIS)
This paper presents an approach to building multi-input and single output fuzzy models. Such a model is composed of fuzzy implications, and its output is inferred by simplified reasoning. The implications are automatically generated by the structure and parameter identification. In the structure identification, the optimal or near optimal number of fuzzy implications is determined in view of valid partition of data set. The parameters defining the implications are identified by a gradient method to minimize mean square errors. Numerical examples are provided to evaluate the feasibility of the proposed number of fuzzy implications than the ones achieved previously in other methods. The proposed approach has also been applied to construct a fuzzy model for the navigation control of a mobile robot. The validity of the resultant model is demonstrated by experimentation. (author)
Haeseler, Friedrich
2003-01-01
Automatic sequences are sequences which are produced by a finite automaton. Although they are not random they may look as being random. They are complicated, in the sense of not being not ultimately periodic, they may look rather complicated, in the sense that it may not be easy to name the rule by which the sequence is generated, however there exists a rule which generates the sequence. The concept automatic sequences has special applications in algebra, number theory, finite automata and formal languages, combinatorics on words. The text deals with different aspects of automatic sequences, in particular:· a general introduction to automatic sequences· the basic (combinatorial) properties of automatic sequences· the algebraic approach to automatic sequences· geometric objects related to automatic sequences.
Institute of Scientific and Technical Information of China (English)
Deepak KAPUR
2006-01-01
A method using quantifier-elimination is proposed for automatically generating program invariants/inductive assertions. Given a program, inductive assertions, hypothesized as parameterized formulas in a theory, are associated with program locations. Parameters in inductive assertions are discovered by generating constraints on parameters by ensuring that an inductive assertion is indeed preserved by all execution paths leading to the associated location of the program. The method can be used to discover loop invariants-properties of variables that remain invariant at the entry of a loop. The parameterized formula can be successively refined by considering execution paths one by one; heuristics can be developed for determining the order in which the paths are considered. Initialization of program variables as well as the precondition and postcondition, if available, can also be used to further refine the hypothesized invariant. The method does not depend on the availability of the precondition and postcondition of a program. Constraints on parameters generated in this way are solved for possible values of parameters. If no solution is possible, this means that an invariant of the hypothesized form is not likely to exist for the loop under the assumptions/approximations made to generate the associated verification condition. Otherwise, if the parametric constraints are solvable, then under certain conditions on methods for generating these constraints, the strongest possible invariant of the hypothesized form can be generated from most general solutions of the parametric constraints. The approach is illustrated using the logical languages of conjunction of polynomial equations as well as Presburger arithmetic for expressing assertions.
Surface meshing with curvature convergence
Li, Huibin
2014-06-01
Surface meshing plays a fundamental role in graphics and visualization. Many geometric processing tasks involve solving geometric PDEs on meshes. The numerical stability, convergence rates and approximation errors are largely determined by the mesh qualities. In practice, Delaunay refinement algorithms offer satisfactory solutions to high quality mesh generations. The theoretical proofs for volume based and surface based Delaunay refinement algorithms have been established, but those for conformal parameterization based ones remain wide open. This work focuses on the curvature measure convergence for the conformal parameterization based Delaunay refinement algorithms. Given a metric surface, the proposed approach triangulates its conformal uniformization domain by the planar Delaunay refinement algorithms, and produces a high quality mesh. We give explicit estimates for the Hausdorff distance, the normal deviation, and the differences in curvature measures between the surface and the mesh. In contrast to the conventional results based on volumetric Delaunay refinement, our stronger estimates are independent of the mesh structure and directly guarantee the convergence of curvature measures. Meanwhile, our result on Gaussian curvature measure is intrinsic to the Riemannian metric and independent of the embedding. In practice, our meshing algorithm is much easier to implement and much more efficient. The experimental results verified our theoretical results and demonstrated the efficiency of the meshing algorithm. © 2014 IEEE.
Tra-la-Lyrics 2.0: Automatic Generation of Song Lyrics on a Semantic Domain
Gonçalo Oliveira, Hugo
2015-12-01
Tra-la-Lyrics is a system that generates song lyrics automatically. In its original version, the main focus was to produce text where stresses matched the rhythm of given melodies. There were no concerns on whether the text made sense or if the selected words shared some kind of semantic association. In this article, we describe the development of a new version of Tra-la-Lyrics, where text is generated on a semantic domain, defined by one or more seed words. This effort involved the integration of the original rhythm module of Tra-la-Lyrics in PoeTryMe, a generic platform that generates poetry with semantically coherent sentences. To measure our progress, the rhythm, the rhymes, and the semantic coherence in lyrics produced by the original Tra-la-Lyrics were analysed and compared with lyrics produced by the new instantiation of this system, dubbed Tra-la-Lyrics 2.0. The analysis showed that, in the lyrics by the new system, words have higher semantic association among them and with the given seeds, while the rhythm is still matched and rhymes are present. The previous analysis was complemented with a crowdsourced evaluation, where contributors answered a survey about relevant features of lyrics produced by the previous and the current versions of Tra-la-Lyrics. Though tight, the survey results confirmed the improvements of the lyrics by Tra-la-Lyrics 2.0.
Kinetic solvers with adaptive mesh in phase space.
Arslanbekov, Robert R; Kolobov, Vladimir I; Frolova, Anna A
2013-12-01
An adaptive mesh in phase space (AMPS) methodology has been developed for solving multidimensional kinetic equations by the discrete velocity method. A Cartesian mesh for both configuration (r) and velocity (v) spaces is produced using a "tree of trees" (ToT) data structure. The r mesh is automatically generated around embedded boundaries, and is dynamically adapted to local solution properties. The v mesh is created on-the-fly in each r cell. Mappings between neighboring v-space trees is implemented for the advection operator in r space. We have developed algorithms for solving the full Boltzmann and linear Boltzmann equations with AMPS. Several recent innovations were used to calculate the discrete Boltzmann collision integral with dynamically adaptive v mesh: the importance sampling, multipoint projection, and variance reduction methods. We have developed an efficient algorithm for calculating the linear Boltzmann collision integral for elastic and inelastic collisions of hot light particles in a Lorentz gas. Our AMPS technique has been demonstrated for simulations of hypersonic rarefied gas flows, ion and electron kinetics in weakly ionized plasma, radiation and light-particle transport through thin films, and electron streaming in semiconductors. We have shown that AMPS allows minimizing the number of cells in phase space to reduce the computational cost and memory usage for solving challenging kinetic problems. PMID:24483578
Kinetic solvers with adaptive mesh in phase space
Arslanbekov, Robert R.; Kolobov, Vladimir I.; Frolova, Anna A.
2013-12-01
An adaptive mesh in phase space (AMPS) methodology has been developed for solving multidimensional kinetic equations by the discrete velocity method. A Cartesian mesh for both configuration (r) and velocity (v) spaces is produced using a “tree of trees” (ToT) data structure. The r mesh is automatically generated around embedded boundaries, and is dynamically adapted to local solution properties. The v mesh is created on-the-fly in each r cell. Mappings between neighboring v-space trees is implemented for the advection operator in r space. We have developed algorithms for solving the full Boltzmann and linear Boltzmann equations with AMPS. Several recent innovations were used to calculate the discrete Boltzmann collision integral with dynamically adaptive v mesh: the importance sampling, multipoint projection, and variance reduction methods. We have developed an efficient algorithm for calculating the linear Boltzmann collision integral for elastic and inelastic collisions of hot light particles in a Lorentz gas. Our AMPS technique has been demonstrated for simulations of hypersonic rarefied gas flows, ion and electron kinetics in weakly ionized plasma, radiation and light-particle transport through thin films, and electron streaming in semiconductors. We have shown that AMPS allows minimizing the number of cells in phase space to reduce the computational cost and memory usage for solving challenging kinetic problems.
Automatic generation and verification of railway interlocking control tables using FSM and NuSMV
Directory of Open Access Journals (Sweden)
Mohammad B. YAZDI
2009-01-01
Full Text Available Due to their important role in providing safe conditions for train movements, railway interlocking systems are considered as safety critical systems. The reliability, safety and integrity of these systems, relies on reliability and integrity of all stages in their lifecycle including the design, verification, manufacture, test, operation and maintenance.In this paper, the Automatic generation and verification of interlocking control tables, as one of the most important stages in the interlocking design process has been focused on, by the safety critical research group in the School of Railway Engineering, SRE. Three different subsystems including a graphical signalling layout planner, a Control table generator and a Control table verifier, have been introduced. Using NuSMV model checker, the control table verifier analyses the contents of control table besides the safe train movement conditions and checks for any conflicting settings in the table. This includes settings for conflicting routes, signals, points and also settings for route isolation and single and multiple overlap situations. The latest two settings, as route isolation and multiple overlap situations are from new outcomes of the work comparing to works represented on the subject recently.
Directory of Open Access Journals (Sweden)
Esha Gupta
2016-01-01
Full Text Available This paper presents an application of the recently introduced Antlion Optimizer (ALO to find the parameters of primary governor loop of thermal generators for successful Automatic Generation Control (AGC of two-area interconnected power system. Two standard objective functions, Integral Square Error (ISE and Integral Time Absolute Error (ITAE, have been employed to carry out this parameter estimation process. The problem is transformed in optimization problem to obtain integral gains, speed regulation, and frequency sensitivity coefficient for both areas. The comparison of the regulator performance obtained from ALO is carried out with Genetic Algorithm (GA, Particle Swarm Optimization (PSO, and Gravitational Search Algorithm (GSA based regulators. Different types of perturbations and load changes are incorporated to establish the efficacy of the obtained design. It is observed that ALO outperforms all three optimization methods for this real problem. The optimization performance of ALO is compared with other algorithms on the basis of standard deviations in the values of parameters and objective functions.
Automatic controller for steam generator water level during low power operation
International Nuclear Information System (INIS)
This research proposes a new controller which ensures a satisfactory automatic control for the steam generator water level from low power to full power. It is premised that the current analog control loop is replaced with digital computer control thus expanding the range of possible solutions. The proposed approach is to compensate the level measurement for thermal shrink and swell effects which cause complications in level control during low power operation. A non-linear digital predictor is a part of the controller and is used to estimate shrink and swell effects. The predictor is found to be stable and on-line applicable with micro-processors. The controller is evaluated by calculations in which it controls an existing non-linear digital computer model of a steam generator. For a multi-ramp power increase from low power to full power, the proposed controller shows good performances for the entire range. Water level settles down within 3 min after a single ramp increase (5% power increase in a minute) without any stability problem. Even at very low power, the maximum overshoot is judged to be acceptable. (orig.)
Bonne, François; Alamir, Mazen; Hoa, Christine; Bonnay, Patrick; Bon-Mardion, Michel; Monteiro, Lionel
2015-12-01
In this article, we present a new Simulink library of cryogenics components (such as valve, phase separator, mixer, heat exchanger...) to assemble to generate model-based control schemes. Every component is described by its algebraic or differential equation and can be assembled with others to build the dynamical model of a complete refrigerator or the model of a subpart of it. The obtained model can be used to automatically design advanced model based control scheme. It also can be used to design a model based PI controller. Advanced control schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in future fusion reactors such as those expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT- 60SA). The paper gives the example of the generation of the dynamical model of the 400W@1.8K refrigerator and shows how to build a Constrained Model Predictive Control for it. Based on the scheme, experimental results will be given. This work is being supported by the French national research agency (ANR) through the ANR-13-SEED-0005 CRYOGREEN program.
Directory of Open Access Journals (Sweden)
Khaled Jerbi
2012-01-01
Full Text Available In this paper, we introduce the Reconfigurable Video Coding (RVC standard based on the idea that video processing algorithms can be defined as a library of components that can be updated and standardized separately. MPEG RVC framework aims at providing a unified high-level specification of current MPEG coding technologies using a dataflow language called Cal Actor Language (CAL. CAL is associated with a set of tools to design dataflow applications and to generate hardware and software implementations. Before this work, the existing CAL hardware compilers did not support high-level features of the CAL. After presenting the main notions of the RVC standard, this paper introduces an automatic transformation process that analyses the non-compliant features and makes the required changes in the intermediate representation of the compiler while keeping the same behavior. Finally, the implementation results of the transformation on video and still image decoders are summarized. We show that the obtained results can largely satisfy the real time constraints for an embedded design on FPGA as we obtain a throughput of 73 FPS for MPEG 4 decoder and 34 FPS for coding and decoding process of the LAR coder using a video of CIF image size. This work resolves the main limitation of hardware generation from CAL designs.
A review of metaphase chromosome image selection techniques for automatic karyotype generation.
Arora, Tanvi; Dhir, Renu
2016-08-01
The karyotype is analyzed to detect the genetic abnormalities. It is generated by arranging the chromosomes after extracting them from the metaphase chromosome images. The chromosomes are non-rigid bodies that contain the genetic information of an individual. The metaphase chromosome image spread contains the chromosomes, but these chromosomes are not distinct bodies; they can either be individual chromosomes or be touching one another; they may be bent or even may be overlapping and thus forming a cluster of chromosomes. The extraction of chromosomes from these touching and overlapping chromosomes is a very tedious process. The segmentation of a random metaphase chromosome image may not give us correct and accurate results. Therefore, before taking up a metaphase chromosome image for analysis, it must be analyzed for the orientation of the chromosomes it contains. The various reported methods for metaphase chromosome image selection for automatic karyotype generation are compared in this paper. After analysis, it has been concluded that each metaphase chromosome image selection method has its advantages and disadvantages. PMID:26676686
Barragán, W.; Campos, A.; Sanchez, G.
2016-06-01
The objective of this research is automatic generation of buildings in the interest areas. This research was developed by using high resolution vertical aerial photographs and the LIDAR point cloud through radiometric and geometric digital processes. The research methodology usesknown building heights and various segmentation algorithms and spectral band combination. The overall effectiveness of the algorithm is 97.2% with the test data.
DEFF Research Database (Denmark)
Basit, Abdul; Hansen, Anca Daniela; Altin, Müfit;
2014-01-01
Transmission system operators have an increased interest in the active participation of wind power plants (WPP) in the power balance control of power systems with large wind power penetration. The emphasis in this study is on the integration of WPPs into the automatic generation control (AGC) of...
Senthil, J; Arumugam, S.; S Margret Anouncia; Abhinav Kapoor
2012-01-01
Today, a lot of web applications and web sites are data driven. These web applications have all the static and dynamic data stored in relational databases. The aim of this thesis is to generate automatic code for data access located in relational databases in minimum time.
Automatic Generation of Algorithms for the Statistical Analysis of Planetary Nebulae Images
Fischer, Bernd
2004-01-01
Analyzing data sets collected in experiments or by observations is a Core scientific activity. Typically, experimentd and observational data are &aught with uncertainty, and the analysis is based on a statistical model of the conjectured underlying processes, The large data volumes collected by modern instruments make computer support indispensible for this. Consequently, scientists spend significant amounts of their time with the development and refinement of the data analysis programs. AutoBayes [GF+02, FS03] is a fully automatic synthesis system for generating statistical data analysis programs. Externally, it looks like a compiler: it takes an abstract problem specification and translates it into executable code. Its input is a concise description of a data analysis problem in the form of a statistical model as shown in Figure 1; its output is optimized and fully documented C/C++ code which can be linked dynamically into the Matlab and Octave environments. Internally, however, it is quite different: AutoBayes derives a customized algorithm implementing the given model using a schema-based process, and then further refines and optimizes the algorithm into code. A schema is a parameterized code template with associated semantic constraints which define and restrict the template s applicability. The schema parameters are instantiated in a problem-specific way during synthesis as AutoBayes checks the constraints against the original model or, recursively, against emerging sub-problems. AutoBayes schema library contains problem decomposition operators (which are justified by theorems in a formal logic in the domain of Bayesian networks) as well as machine learning algorithms (e.g., EM, k-Means) and nu- meric optimization methods (e.g., Nelder-Mead simplex, conjugate gradient). AutoBayes augments this schema-based approach by symbolic computation to derive closed-form solutions whenever possible. This is a major advantage over other statistical data analysis systems
Automatic Stress Testing of Multi-tier Systems by Dynamic Bottleneck Switch Generation
Casale, Giuliano; Kalbasi, Amir; Krishnamurthy, Diwakar; Rolia, Jerry
The performance of multi-tier systems is known to be significantly degraded by workloads that place bursty service demands on system resources. Burstiness can cause queueing delays, oversubscribe limited threading resources, and even cause dynamic bottleneck switches between resources. Thus, there is need for a methodology to create benchmarks with controlled burstiness and bottleneck switches to evaluate their impact on system performance. We tackle this problem using a model-based technique for the automatic and controlled generation of bursty benchmarks. Markov models are constructed in an automated manner to model the distribution of service demands placed by sessions of a given system on various system resources. The models are then used to derive session submission policies that result in user-specified levels of service demand burstiness for resources at the different tiers in a system. Our approach can also predict under what conditions these policies can create dynamic bottleneck switching among resources. A case study using a three-tier TPC-W testbed shows that our method is able to control and predict burstiness for session service demands. Further, results from the study demonstrate that our approach was able to inject controlled bottleneck switches. Experiments show that these bottleneck switches cause dramatic latency and throughput degradations that are not shown by the same session mix with non-bursty conditions.
Sunnåker, Mikael; Zamora-Sillero, Elias; Dechant, Reinhard; Ludwig, Christina; Busetto, Alberto Giovanni; Wagner, Andreas; Stelling, Joerg
2013-05-28
Predictive dynamical models are critical for the analysis of complex biological systems. However, methods to systematically develop and discriminate among systems biology models are still lacking. We describe a computational method that incorporates all hypothetical mechanisms about the architecture of a biological system into a single model and automatically generates a set of simpler models compatible with observational data. As a proof of principle, we analyzed the dynamic control of the transcription factor Msn2 in Saccharomyces cerevisiae, specifically the short-term mechanisms mediating the cells' recovery after release from starvation stress. Our method determined that 12 of 192 possible models were compatible with available Msn2 localization data. Iterations between model predictions and rationally designed phosphoproteomics and imaging experiments identified a single-circuit topology with a relative probability of 99% among the 192 models. Model analysis revealed that the coupling of dynamic phenomena in Msn2 phosphorylation and transport could lead to efficient stress response signaling by establishing a rate-of-change sensor. Similar principles could apply to mammalian stress response pathways. Systematic construction of dynamic models may yield detailed insight into nonobvious molecular mechanisms. PMID:23716718
Iqpc 2015 Track: Evaluation of Automatically Generated 2d Footprints from Urban LIDAR Data
Truong-Hong, L.; Laefer, D.; Bisheng, Y.; Ronggang, H.; Jianping, L.
2015-08-01
Over the last decade, several automatic approaches have been proposed to extract and reconstruct 2D building footprints and 2D road profiles from ALS data, satellite images, and/or aerial imagery. Since these methods have to date been applied to various data sets and assessed through a variety of different quality indicators and ground truths, comparing the relative effectiveness of the techniques and identifying their strengths and short-comings has not been possible in a systematic way. This contest as part of IQPC15 was designed to determine pros and cons of submitted approaches in generating 2D footprint of a city region from ALS data. Specifically, participants were asked to submit 2D footprints (building outlines and road profiles) derived from ALS data from a highly dense dataset (approximately 225 points/m2) across a 1km2 of Dublin, Ireland's city centre. The proposed evaluation strategies were designed to measure not only the capacity of each method to detect and reconstruct 2D buildings and roads but also the quality of the reconstructed building and road models in terms of shape similarity and positional accuracy.
Performing Label-Fusion-Based Segmentation Using Multiple Automatically Generated Templates
Chakravarty, M. Mallar; Steadman, Patrick; van Eede, Matthijs C.; Calcott, Rebecca D.; Gu, Victoria; Shaw, Philip; Raznahan, Armin; Collins, D. Louis; Lerch, Jason P.
2016-01-01
Classically, model-based segmentation procedures match magnetic resonance imaging (MRI) volumes to an expertly labeled atlas using nonlinear registration. The accuracy of these techniques are limited due to atlas biases, misregistration, and resampling error. Multi-atlas-based approaches are used as a remedy and involve matching each subject to a number of manually labeled templates. This approach yields numerous independent segmentations that are fused using a voxel-by-voxel label-voting procedure. In this article, we demonstrate how the multi-atlas approach can be extended to work with input atlases that are unique and extremely time consuming to construct by generating a library of multiple automatically generated templates of different brains (MAGeT Brain). We demonstrate the efficacy of our method for the mouse and human using two different nonlinear registration algorithms (ANIMAL and ANTs). The input atlases consist a high-resolution mouse brain atlas and an atlas of the human basal ganglia and thalamus derived from serial histological data. MAGeT Brain segmentation improves the identification of the mouse anterior commissure (mean Dice Kappa values (κ = 0.801), but may be encountering a ceiling effect for hippocampal segmentations. Applying MAGeT Brain to human subcortical structures improves segmentation accuracy for all structures compared to regular model-based techniques (κ = 0.845, 0.752, and 0.861 for the striatum, globus pallidus, and thalamus, respectively). Experiments performed with three manually derived input templates suggest that MAGeT Brain can approach or exceed the accuracy of multi-atlas label-fusion segmentation (κ = 0.894, 0.815, and 0.895 for the striatum, globus pallidus, and thalamus, respectively). PMID:22611030
Generic Mesh Refinement On GPU
Boubekeur, Tamy; Schlick, Christophe
2005-01-01
International audience Many recent publications have shown that a large variety of computation involved in computer graphics can be moved from the CPU to the GPU, by a clever use of vertex or fragment shaders. Nonetheless there is still one kind of algorithms that is hard to translate from CPU to GPU: mesh refinement techniques. The main reason for this, is that vertex shaders available on current graphics hardware do not allow the generation of additional vertices on a mesh stored in grap...
Particle systems for adaptive, isotropic meshing of CAD models.
Bronson, Jonathan R; Levine, Joshua A; Whitaker, Ross T
2012-10-01
We present a particle-based approach for generating adaptive triangular surface and tetrahedral volume meshes from computer-aided design models. Input shapes are treated as a collection of smooth, parametric surface patches that can meet non-smoothly on boundaries. Our approach uses a hierarchical sampling scheme that places particles on features in order of increasing dimensionality. These particles reach a good distribution by minimizing an energy computed in 3D world space, with movements occurring in the parametric space of each surface patch. Rather than using a pre-computed measure of feature size, our system automatically adapts to both curvature as well as a notion of topological separation. It also enforces a measure of smoothness on these constraints to construct a sizing field that acts as a proxy to piecewise-smooth feature size. We evaluate our technique with comparisons against other popular triangular meshing techniques for this domain. PMID:23162181
Matching and Clustering: Two Steps Towards Automatic Model Generation in Computer Vision
Gros, Patrick
1993-01-01
International audience In this paper, we present a general frame for a system of automatic modelling and recognition of 3D polyhedral objects. Such a system has many applications for robotics : recognition, localization, grasping,...Here we focus upon one main aspect of the system : when many images of one 3D object are taken from different unknown viewpoints, how to recognize those of them which represent the same aspect of the object ? Briefly, it is possible to determine automatically i...
Directory of Open Access Journals (Sweden)
Ole Green
2011-03-01
Full Text Available Progress is constantly being made and new applications are constantly coming out in the area of field robotics. In this paper, a promising application of field robotics in football playing fields is introduced. An algorithmic approach for generating the way points required for the guidance of a GPS-based field robotic through a football playing field to automatically carry out periodical tasks such as cutting the grass field, pitch and line marking illustrations and lawn striping is represented. The manual operation of these tasks requires very skilful personnel able to work for long hours with very high concentration for the football yard to be compatible with standards of Federation Internationale de Football Association (FIFA. In the other side, a GPS-based guided vehicle or robot with three implements; grass mower, lawn stripping roller and track marking illustrator is capable of working 24 h a day, in most weather and in harsh soil conditions without loss of quality. The proposed approach for the automatic operation of football playing fields requires no or very limited human intervention and therefore it saves numerous working hours and free a worker to focus on other tasks. An economic feasibility study showed that the proposed method is economically superimposing the current manual practices.
International Nuclear Information System (INIS)
This study intends to develop a more sophisticated tool that will advance the current event tree method used in all PSA, and to focus on non-catastrophic events, specifically a non-core melt sequence scenario not included in an ordinary PSA. In the non-catastrophic event PSA, it is necessary to consider various end states and failure combinations for the purpose of multiple scenario construction. Therefore it is anticipated that an analysis work should be reduced and automated method and tool is required. A scenario generator that can automatically handle scenario construction logic and generate the enormous size of sequences logically identified by state-of-the-art methodology was developed. To fulfill the scenario generation as a technical tool, a simulation model associated with AI technique and graphical interface, was introduced. The AI simulation model in this study was verified for the feasibility of its capability to evaluate actual systems. In this feasibility study, a spurious SI signal was selected to test the model's applicability. As a result, the basic capability of the scenario generator could be demonstrated and important scenarios were generated. The human interface with a system and its operation, as well as time dependent factors and their quantification in scenario modeling, was added utilizing human scenario generator concept. Then the feasibility of an improved scenario generator was tested for actual use. Automatic scenario generation with a certain level of credibility, was achieved by this study. (author)
Directory of Open Access Journals (Sweden)
M. Varchola
2009-12-01
Full Text Available This paper deals with an evaluation platform for cryptographic True Random Number Generators (TRNGs based on the hardware implementation of statistical tests for FPGAs. It was developed in order to provide an automatic tool that helps to speed up the TRNG design process and can provide new insights on the TRNG behavior as it will be shown on a particular example in the paper. It enables to test sufﬁcient statistical properties of various TRNG designs under various working conditions on the ﬂy. Moreover, the tests are suitable to be embedded into cryptographic hardware products in order to recognize TRNG output of weak quality and thus increase its robustness and reliability. Tests are fully compatible with the FIPS 140 standard and are implemented by the VHDL language as an IP-Core for vendor independent FPGAs. A recent Flash based Actel Fusion FPGA was chosen for preliminary experiments. The Actel version of the tests possesses an interface to the Actel’s CoreMP7 softcore processor that is fully compatible with the industry standard ARM7TDMI. Moreover, identical tests suite was implemented to the Xilinx Virtex 2 and 5 in order to compare the performance of the proposed solution with the performance of already published one based on the same FPGAs. It was achieved 25% and 65% greater clock frequency respectively while consuming almost equal resources of the Xilinx FPGAs. On the top of it, the proposed FIPS 140 architecture is capable of processing one random bit per one clock cycle which results in 311.5 Mbps throughput for Virtex 5 FPGA.
Automatic test pattern generation for stuck-at and delay faults in combinational circuits
International Nuclear Information System (INIS)
The present studies are developed to propose the automatic test pattern generation (ATG) algorithms for combinational circuits. These ATG algorithms are realized in two ATG programs: One is the ATG program for stuck-at fault and the other one for delay faults. In order to accelerate the ATG process, these two ATG programs have a common feature (the search method based on the concept of the degree of freedom), whereas only ATG program for the delay fault utilizes the 19-valued logic, a type of composite valued logic. This difference between two ATG programs results from the difference of the target fault. Accelerating the ATG process is indispensable for improving the ATG algorithms. This acceleration is mainly achieved by reducing the number of the unnecessary backtrackings, making the earlier detection of the conflicts, and shortening the computation time between the implication. Because of this purpose, the developed ATG programs include the new search method based on the concept of the degree of freedom (DF). The DF concept, computed directly and easily from the system descriptions such as types of gates and their interconnections, is the criterion to decide which, among several alternate lines' logic values required along each path, promises to be the most effective in order to accelerate and improve the ATG process. This DF concept is utilized to develop and improve both of ATG programs for stuck-at and delay faults in combinational circuits. In addition to improving the ATG process, reducing number of test pattern is indispensable for testing the delay faults because the size of the delay faults grows rapidly as increasing the size of the circuit. In order to improve the compactness of the test set, 19-valued logic are derived. Unlike other TG logic systems, 19-valued logic is utilized to generate the robustly hazard-free test pattern. This is achieved by using the basic 5-valued logic, proposed in this work, where the transition with no hazard is
A semi-automatic multiple view texture mapping for the surface model extracted by laser scanning
Zhang, Zhichao; Huang, Xianfeng; Zhang, Fan; Chang, Yongmin; Li, Deren
2008-12-01
Laser scanning is an effective way to acquire geometry data of the cultural heritage with complex architecture. After generating the 3D model of the object, it's difficult to do the exactly texture mapping for the real object. we take effort to create seamless texture maps for a virtual heritage of arbitrary topology. Texture detail is acquired directly from the real object in a light condition as uniform as we can make. After preprocessing, images are then registered on the 3D mesh by a semi-automatic way. Then we divide the mesh into mesh patches overlapped with each other according to the valid texture area of each image. An optimal correspondence between mesh patches and sections of the acquired images is built. Then, a smoothing approach is proposed to erase the seam between different images that map on adjacent mesh patches, based on texture blending. The obtained result with a Buddha of Dunhuang Mogao Grottoes is presented and discussed.
Matthews, Devin A.; Gong, Justin Z.; Stanton, John F.
2014-06-01
The derivation of analytic expressions for vibrational and rovibrational constants, for example the anharmonicity constants χij and the vibration-rotation interaction constants α^B_r, from second-order vibrational perturbation theory (VPT2) can be accomplished with pen and paper and some practice. However, the corresponding quantities from fourth-order perturbation theory (VPT4) are considerably more complex, with the only known derivations by hand extensively using many layers of complicated intermediates and for rotational quantities requiring specialization to orthorhombic cases or the form of Watson's reduced Hamiltonian. We present an automatic computer program for generating these expressions with full generality based on the adaptation of an existing numerical program based on the sum-over-states representation of the energy to a computer algebra context. The measures taken to produce well-simplified and factored expressions in an efficient manner are discussed, as well as the framework for automatically checking the correctness of the generated equations.
Optimizing the geometrical accuracy of curvilinear meshes
Toulorge, Thomas; Remacle, Jean-François
2015-01-01
This paper presents a method to generate valid high order meshes with optimized geometrical accuracy. The high order meshing procedure starts with a linear mesh, that is subsequently curved without taking care of the validity of the high order elements. An optimization procedure is then used to both untangle invalid elements and optimize the geometrical accuracy of the mesh. Standard measures of the distance between curves are considered to evaluate the geometrical accuracy in planar two-dimensional meshes, but they prove computationally too costly for optimization purposes. A fast estimate of the geometrical accuracy, based on Taylor expansions of the curves, is introduced. An unconstrained optimization procedure based on this estimate is shown to yield significant improvements in the geometrical accuracy of high order meshes, as measured by the standard Haudorff distance between the geometrical model and the mesh. Several examples illustrate the beneficial impact of this method on CFD solutions, with a part...
International Nuclear Information System (INIS)
Module-based Simulation System (MSS) has been developed to realize a new software work environment enabling versatile dynamic simulation of a complex nuclear power system flexibly. The MSS makes full use of modern software technology to replace a large fraction of human software works in complex, large-scale program development by computer automation. Fundamental methods utilized in MSS and developmental study on human interface system SESS-1 to help users in generating integrated simulation programs automatically are summarized as follows: (1) To enhance usability and 'communality' of program resources, the basic mathematical models of common usage in nuclear power plant analysis are programed as 'modules' and stored in a module library. The information on usage of individual modules are stored in module database with easy registration, update and retrieval by the interactive management system. (2) Target simulation programs and the input/output files are automatically generated with simple block-wise languages by a precompiler system for module integration purpose. (3) Working time for program development and analysis in an example study of an LMFBR plant thermal-hydraulic transient analysis was demonstrated to be remarkably shortened, with the introduction of an interface system SESS-1 developed as an automatic program generation environment. (author)
An automatic method to generate domain-specific investigator networks using PubMed abstracts
Directory of Open Access Journals (Sweden)
Gwinn Marta
2007-06-01
Full Text Available Abstract Background Collaboration among investigators has become critical to scientific research. This includes ad hoc collaboration established through personal contacts as well as formal consortia established by funding agencies. Continued growth in online resources for scientific research and communication has promoted the development of highly networked research communities. Extending these networks globally requires identifying additional investigators in a given domain, profiling their research interests, and collecting current contact information. We present a novel strategy for building investigator networks dynamically and producing detailed investigator profiles using data available in PubMed abstracts. Results We developed a novel strategy to obtain detailed investigator information by automatically parsing the affiliation string in PubMed records. We illustrated the results by using a published literature database in human genome epidemiology (HuGE Pub Lit as a test case. Our parsing strategy extracted country information from 92.1% of the affiliation strings in a random sample of PubMed records and in 97.0% of HuGE records, with accuracies of 94.0% and 91.0%, respectively. Institution information was parsed from 91.3% of the general PubMed records (accuracy 86.8% and from 94.2% of HuGE PubMed records (accuracy 87.0. We demonstrated the application of our approach to dynamic creation of investigator networks by creating a prototype information system containing a large database of PubMed abstracts relevant to human genome epidemiology (HuGE Pub Lit, indexed using PubMed medical subject headings converted to Unified Medical Language System concepts. Our method was able to identify 70–90% of the investigators/collaborators in three different human genetics fields; it also successfully identified 9 of 10 genetics investigators within the PREBIC network, an existing preterm birth research network. Conclusion We successfully created a
Energy Technology Data Exchange (ETDEWEB)
Leal, L.C.; Hermann, O.W.; Bowman, S.M.; Parks, C.V.
1998-04-01
In this report, a methodology is described which serves as an alternative to the SAS2H path of the SCALE system to generate cross sections for point-depletion calculations with the ORIGEN-S code. ARP, Automatic Rapid Processing, is an algorithm that allows the generation of cross-section libraries suitable to the ORIGEN-S code by interpolation over pregenerated SAS2H libraries. The interpolations are carried out on the following variables: burnup, enrichment, and water density. The adequacy of the methodology is evaluated by comparing measured and computed spent fuel isotopic compositions for PWR and BWR systems.
International Nuclear Information System (INIS)
A methodology is described that serves as an alternative to the SAS2H path of the SCALE system to generate cross sections for point-depletion calculations with the ORIGEN-S code. Automatic Rapid Processing (ARP) is an algorithm that allows the generation of cross-section libraries suitable to the ORIGEN-S code by interpolation over pregenerated SAS2H libraries. The interpolations are carried out on the following variables: burnup, enrichment, and water density. The adequacy of the methodology is evaluated by comparing measured and computed spent-fuel isotopic compositions for pressurized water reactor and boiling water reactor systems
Meshing Highly Regular Structures: The Case of Super Carbon Nanotubes of Arbitrary Order
Directory of Open Access Journals (Sweden)
Christian Schröppel
2015-01-01
Full Text Available Mesh generation is an important step in many numerical methods. We present the “Hierarchical Graph Meshing” (HGM method as a novel approach to mesh generation, based on algebraic graph theory. The HGM method can be used to systematically construct configurations exhibiting multiple hierarchies and complex symmetry characteristics. The hierarchical description of structures provided by the HGM method can be exploited to increase the efficiency of multiscale and multigrid methods. In this paper, the HGM method is employed for the systematic construction of super carbon nanotubes of arbitrary order, which present a pertinent example of structurally and geometrically complex, yet highly regular, structures. The HGM algorithm is computationally efficient and exhibits good scaling characteristics. In particular, it scales linearly for super carbon nanotube structures and is working much faster than geometry-based methods employing neighborhood search algorithms. Its modular character makes it conducive to automatization. For the generation of a mesh, the information about the geometry of the structure in a given configuration is added in a way that relates geometric symmetries to structural symmetries. The intrinsically hierarchic description of the resulting mesh greatly reduces the effort of determining mesh hierarchies for multigrid and multiscale applications and helps to exploit symmetry-related methods in the mechanical analysis of complex structures.
High-fidelity simulations of blast loadings in urban environments using an overset meshing strategy
Wang, X.; Remotigue, M.; Arnoldus, Q.; Janus, M.; Luke, E.; Thompson, D.; Weed, R.; Bessette, G.
2016-07-01
Detailed blast propagation and evolution through multiple structures representing an urban environment were simulated using the code Loci/BLAST, which employs an overset meshing strategy. The use of overset meshes simplifies mesh generation by allowing meshes for individual component geometries to be generated independently. Detailed blast propagation and evolution through multiple structures, wave reflection and interaction between structures, and blast loadings on structures were simulated and analyzed. Predicted results showed good agreement with experimental data generated by the US Army Engineer Research and Development Center. Loci/BLAST results were also found to compare favorably to simulations obtained using the Second-Order Hydrodynamic Automatic Mesh Refinement Code (SHAMRC). The results obtained demonstrated that blast reflections in an urban setting significantly increased the blast loads on adjacent buildings. Correlations of computational results with experimental data yielded valuable insights into the physics of blast propagation, reflection, and interaction under an urban setting and verified the use of Loci/BLAST as a viable tool for urban blast analysis.
Kobayashi, Kazunobu; Kulinich, S. A.; Ito, Tsuyohito
2014-09-01
Methane gas conversion was studied in customized flow-type reactors with different dielectric barrier discharge generated in Ar-CH4-O2 gas mixtures. Different reactor geometries (with either volume or surface-type discharges) and different electrode materials were compared, and gas temperatures during methane conversion processes were evaluated. The discharge was generated by applying either a conventional sinusoid or nanosecond-pulsed voltage. The methane conversion rate was as high as ˜99% with the total gas flow rate of 15 sccm, while the temperatures did not exceed 450 K. No significant effect of electrode material (stainless steel, aluminum, or CuO coated copper) was found, confirming that the conversion temperatures were much lower than those required for activity of typical catalysts. The reactor geometry, flow rate, and oxygen amount could be used to govern both the methane conversion rate and the fractions of components in the final product.
International Nuclear Information System (INIS)
In this paper, an improved algorithm for automatic test pattern generation (ATG) for nuclear power plant digital electronic circuits--the combinational type of logic circuits is presented. For accelerating and improving the ATG process for combinational circuits the presented ATG algorithm has the new concept--the degree of freedom (DF). The DF, directly computed from the system descriptions such as types of gates and their interconnections, is the criterion to decide which among several alternate lines' logic values required along each path promises to be the most effective in order to accelerate and improve the ATG process. Based on the DF the proposed ATG algorithm is implemented in the automatic fault diagnosis system (AFDS) which incorporates the advanced fault diagnosis method of artificial intelligence technique, it is shown that the AFDS using the ATG algorithm makes Universal Card (UV Card) testing much faster than the present testing practice or by using exhaustive testing sets
Unstructured Polyhedral Mesh Thermal Radiation Diffusion
Energy Technology Data Exchange (ETDEWEB)
Palmer, T.S.; Zika, M.R.; Madsen, N.K.
2000-07-27
Unstructured mesh particle transport and diffusion methods are gaining wider acceptance as mesh generation, scientific visualization and linear solvers improve. This paper describes an algorithm that is currently being used in the KULL code at Lawrence Livermore National Laboratory to solve the radiative transfer equations. The algorithm employs a point-centered diffusion discretization on arbitrary polyhedral meshes in 3D. We present the results of a few test problems to illustrate the capabilities of the radiation diffusion module.
Unstructured Polyhedral Mesh Thermal Radiation Diffusion
International Nuclear Information System (INIS)
Unstructured mesh particle transport and diffusion methods are gaining wider acceptance as mesh generation, scientific visualization and linear solvers improve. This paper describes an algorithm that is currently being used in the KULL code at Lawrence Livermore National Laboratory to solve the radiative transfer equations. The algorithm employs a point-centered diffusion discretization on arbitrary polyhedral meshes in 3D. We present the results of a few test problems to illustrate the capabilities of the radiation diffusion module
Plagiarism meets paraphrasing: insights for the new generation in automatic plagiarism detection
Barrón-Cedeño, Alberto; Vila Rigat, Marta; Martí Antonin, M. Antònia; Rosso, Paolo
2013-01-01
Although paraphrasing is the linguistic mechanism underlying many plagiarism cases, little attention has been paid to its analysis in the framework of automatic plagiarism detection. Therefore, state-of-the-art plagiarism detectors find it difficult to detect cases of paraphrase plagiarism. In this article, we analyse the relationship between paraphrasing and plagiarism, paying special attention to which paraphrase phenomena underlie acts of plagiarism and which of them are detected by plagia...
Plagiarism meets paraphrasing: insights for the next generation in automatic plagiarism detection
Barrón-Cedeño, Alberto; Vila, Marta; Martí, Maria Antonia; Rosso, Paolo
2013-01-01
Although paraphrasing is the linguistic mechanism underlying many plagiarism cases, little attention has been paid to its analysis in the framework of automatic plagiarism detection. Therefore, state-of-the-art plagiarism detectors find it difficult to detect cases of paraphrase plagiarism. In this article, we analyze the relationship between paraphrasing and plagiarism, paying special attention to which paraphrase phenomena underlie acts of plagiarism and which of them are detected by plagia...
Automatic generation of groundwater model hydrostratigraphy from AEM resistivity and boreholes
DEFF Research Database (Denmark)
Marker, Pernille Aabye; Foged, N.; Christiansen, A. V.;
2014-01-01
Regional hydrological models are important tools in water resources management. Model prediction uncertainty is primarily due to structural (geological) non-uniqueness which makes sampling of the structural model space necessary to estimate prediction uncertainties. Geological structures and...... heterogeneity, which spatially scarce borehole lithology data may overlook, are well resolved in AEM surveys. This study presents a semi-automatic sequential hydrogeophysical inversion method for the integration of AEM and borehole data into regional groundwater models in sedimentary areas, where sand/ clay...
Visual analytics for automatic quality assessment of user-generated content on the English Wikipedia
David Strohmaier; Lindstaedt, Stefanie; Veas, Eduardo; Di Sciascio, Cecilia
2015-01-01
Related work has shown that it is possible to automatically measure the quality of Wikipedia articles. Yet, despite all these quality measures, it is difficult to identify what would improve an article. Therefore this master thesis is about an interactive graphic tool made for ranking and editing Wikipedia articles with support from quality measures. The contribution of this work is twofold: i) The Quality Analyzer that allows for creating new ...
David Strohmaier
2015-01-01
Related work has shown that it is possible to automatically measure the quality of Wikipedia articles. Yet, despite all these quality measures, it is difficult to identify what would improve an article. Therefore this master thesis is about an interactive graphic tool made for ranking and editing Wikipedia articles with support from quality measures. The contribution of this work is twofold: i) The Quality Analyzer that allows for creating new quality metrics and co...
Automatic Texture Reconstruction of 3d City Model from Oblique Images
Kang, Junhua; Deng, Fei; Li, Xinwei; Wan, Fang
2016-06-01
In recent years, the photorealistic 3D city models are increasingly important in various geospatial applications related to virtual city tourism, 3D GIS, urban planning, real-estate management. Besides the acquisition of high-precision 3D geometric data, texture reconstruction is also a crucial step for generating high-quality and visually realistic 3D models. However, most of the texture reconstruction approaches are probably leading to texture fragmentation and memory inefficiency. In this paper, we introduce an automatic framework of texture reconstruction to generate textures from oblique images for photorealistic visualization. Our approach include three major steps as follows: mesh parameterization, texture atlas generation and texture blending. Firstly, mesh parameterization procedure referring to mesh segmentation and mesh unfolding is performed to reduce geometric distortion in the process of mapping 2D texture to 3D model. Secondly, in the texture atlas generation step, the texture of each segmented region in texture domain is reconstructed from all visible images with exterior orientation and interior orientation parameters. Thirdly, to avoid color discontinuities at boundaries between texture regions, the final texture map is generated by blending texture maps from several corresponding images. We evaluated our texture reconstruction framework on a dataset of a city. The resulting mesh model can get textured by created texture without resampling. Experiment results show that our method can effectively mitigate the occurrence of texture fragmentation. It is demonstrated that the proposed framework is effective and useful for automatic texture reconstruction of 3D city model.
Directory of Open Access Journals (Sweden)
DAHIYA, P.
2015-05-01
Full Text Available This paper presents the application of hybrid opposition based disruption operator in gravitational search algorithm (DOGSA to solve automatic generation control (AGC problem of four area hydro-thermal-gas interconnected power system. The proposed DOGSA approach combines the advantages of opposition based learning which enhances the speed of convergence and disruption operator which has the ability to further explore and exploit the search space of standard gravitational search algorithm (GSA. The addition of these two concepts to GSA increases its flexibility for solving the complex optimization problems. This paper addresses the design and performance analysis of DOGSA based proportional integral derivative (PID and fractional order proportional integral derivative (FOPID controllers for automatic generation control problem. The proposed approaches are demonstrated by comparing the results with the standard GSA, opposition learning based GSA (OGSA and disruption based GSA (DGSA. The sensitivity analysis is also carried out to study the robustness of DOGSA tuned controllers in order to accommodate variations in operating load conditions, tie-line synchronizing coefficient, time constants of governor and turbine. Further, the approaches are extended to a more realistic power system model by considering the physical constraints such as thermal turbine generation rate constraint, speed governor dead band and time delay.
Directory of Open Access Journals (Sweden)
CARVALHO, J. S. C.
2008-12-01
Full Text Available During the development of software one of the most visible risks and perhaps the biggest implementation obstacle relates to the time management. All delivery deadlines software versions must be followed, but it is not always possible, sometimes due to delay in coding. This paper presents a metamodel for software implementation, which will rise to a development tool for automatic generation of source code, in order to make any development pattern transparent to the programmer, significantly reducing the time spent in coding artifacts that make up the software.
DEFF Research Database (Denmark)
Franz, Michael; Gal, Andreas; Probst, Christian
As older mainframe architectures become obsolete, the corresponding le- gacy software is increasingly executed via platform emulators running on top of more modern commodity hardware. These emulators are virtual machines that often include a combination of interpreters and just-in-time compilers....... Implementing interpreters and compilers for each combination of emulated and target platform independently of each other is a redundant and error-prone task. We describe an alternative approach that automatically synthesizes specialized virtual-machine interpreters and just-in-time compilers, which then...... execute on top of an existing software portability platform such as Java. The result is a considerably reduced implementation effort....
Institute of Scientific and Technical Information of China (English)
XU Benzhu; ZHU Jiman; LIU Xiaoping
2012-01-01
Identifying each process and their constraint relations from the complex wiring harness drawings quickly and accurately is the basis for formulating process routes. According to the knowledge of automotive wiring harness and the characteristics of wiring harness components, we established the model of wiring harness graph. Then we research the algorithm of identifying technology processes automatically, finally we describe the relationships between processes by introducing the constraint matrix, which is in or- der to lay a good foundation for harness process planning and production scheduling.
SUNMAP: A Tool for Automatic Topology Selection and Generation for NoCs
Murali, Srinivasan; Micheli, Giovanni De
2004-01-01
Increasing communication demands of processor and memory cores in Systems on Chips (SoCs) necessitate the use of Networks on Chip (NoC) to interconnect the cores. An important phase in the design of NoCs is the mapping of cores onto the most suitable topology for a given application. In this paper, we present SUNMAP a tool for automatically selecting the best topology for a given application and producing a mapping of cores onto that topology. SUNMAP explores various design objective such as ...
Directory of Open Access Journals (Sweden)
Mukta Majumder
2014-12-01
Full Text Available Traditional education cannot meet the expectation and requirement of a Smart City; it require more advance forms like active learning, ICT education etc. Multiple choice questions (MCQs play an important role in educational assessment and active learning which has a key role in Smart City education. MCQs are effective to assess the understanding of well-defined concepts. A fraction of all the sentences of a text contain well-defined concepts or information that can be asked as a MCQ. These informative sentences are required to be identified first for preparing multiple choice questions manually or automatically. In this paper we propose a technique for automatic identification of such informative sentences that can act as the basis of MCQ. The technique is based on parse structure similarity. A reference set of parse structures is compiled with the help of existing MCQs. The parse structure of a new sentence is compared with the reference structures and if similarity is found then the sentence is considered as a potential candidate. Next a rule-based post-processing module works on these potential candidates to select the final set of informative sentences. The proposed approach is tested in sports domain, where many MCQs are easily available for preparing the reference set of structures. The quality of the system selected sentences is evaluated manually. The experimental result shows that the proposed technique is quite promising.
Liu, Rong
2009-01-01
Polygonal meshes are ubiquitous in geometric modeling. They are widely used in many applications, such as computer games, computer-aided design, animation, and visualization. One of the important problems in mesh processing and analysis is segmentation, where the goal is to partition a mesh into segments to suit the particular application at hand. In this thesis we study structural-level mesh segmentation, which seeks to decompose a given 3D shape into parts according to human intuition. We t...
Oniga, E.
2012-07-01
The result of the terrestrial laser scanning is an impressive number of spatial points, each of them being characterized as position by the X, Y and Z co-ordinates, by the value of the laser reflectance and their real color, expressed as RGB (Red, Green, Blue) values. The color code for each LIDAR point is taken from the georeferenced digital images, taken with a high resolution panoramic camera incorporated in the scanner system. In this article I propose a new algorithm for the semiautomatic texture generation, using the color information, the RGB values of every point that has been taken by terrestrial laser scanning technology and the 3D surfaces defining the buildings facades, generated with the Leica Cyclone software. The first step is when the operator defines the limiting value, i.e. the minimum distance between a point and the closest surface. The second step consists in calculating the distances, or the perpendiculars drawn from each point to the closest surface. In the third step we associate the points whose 3D coordinates are known, to every surface, depending on the limiting value. The fourth step consists in computing the Voronoi diagram for the points that belong to a surface. The final step brings automatic association between the RGB value of the color code and the corresponding polygon of the Voronoi diagram. The advantage of using this algorithm is that we can obtain, in a semi-automatic manner, a photorealistic 3D model of the building.
Connectivity editing for quadrilateral meshes
Peng, Chihan
2011-12-12
We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and impossible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing operations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular vertices (i.e., two). The irregular vertex movement operations are supplemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed highlevel operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadrangulation techniques. © 2011 ACM.
Connectivity editing for quadrilateral meshes
Peng, Chihan
2011-12-01
We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and impossible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing operations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular vertices (i.e., two). The irregular vertex movement operations are supplemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed high-level operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadrangulation techniques.
Highly Symmetric and Congruently Tiled Meshes for Shells and Domes
Rasheed, Muhibur; Bajaj, Chandrajit
2016-01-01
We describe the generation of all possible shell and dome shapes that can be uniquely meshed (tiled) using a single type of mesh face (tile), and following a single meshing (tiling) rule that governs the mesh (tile) arrangement with maximal vertex, edge and face symmetries. Such tiling arrangements or congruently tiled meshed shapes, are frequently found in chemical forms (fullerenes or Bucky balls, crystals, quasi-crystals, virus nano shells or capsids), and synthetic shapes (cages, sports domes, modern architectural facades). Congruently tiled meshes are both aesthetic and complete, as they support maximal mesh symmetries with minimal complexity and possess simple generation rules. Here, we generate congruent tilings and meshed shape layouts that satisfy these optimality conditions. Further, the congruent meshes are uniquely mappable to an almost regular 3D polyhedron (or its dual polyhedron) and which exhibits face-transitive (and edge-transitive) congruency with at most two types of vertices (each type transitive to the other). The family of all such congruently meshed polyhedra create a new class of meshed shapes, beyond the well-studied regular, semi-regular and quasi-regular classes, and their duals (platonic, Catalan and Johnson). While our new mesh class is infinite, we prove that there exists a unique mesh parametrization, where each member of the class can be represented by two integer lattice variables, and moreover efficiently constructable.
A Solar Automatic Tracking System that Generates Power for Lighting Greenhouses
Qi-Xun Zhang; Hai-Ye Yu; Qiu-Yuan Zhang; Zhong-Yuan Zhang; Cheng-Hui Shao; Di Yang
2015-01-01
In this study we design and test a novel solar tracking generation system. Moreover, we show that this system could be successfully used as an advanced solar power source to generate power in greenhouses. The system was developed after taking into consideration the geography, climate, and other environmental factors of northeast China. The experimental design of this study included the following steps: (i) the novel solar tracking generation system was measured, and its performance was analyz...
Altyntsev, M. A.; Arbuzov, S. A.; Popov, R. A.; Tsoi, G. V.; Gromov, M. O.
2016-06-01
A dense digital surface model is one of the products generated by using UAV aerial survey data. Today more and more specialized software are supplied with modules for generating such kind of models. The procedure for dense digital model generation can be completely or partly automated. Due to the lack of reliable criterion of accuracy estimation it is rather complicated to judge the generation validity of such models. One of such criterion can be mobile laser scanning data as a source for the detailed accuracy estimation of the dense digital surface model generation. These data may be also used to estimate the accuracy of digital orthophoto plans created by using UAV aerial survey data. The results of accuracy estimation for both kinds of products are presented in the paper.
Weakly supervised automatic segmentation and 3D modeling of the knee joint from MR images
Amami, Amal; Ben Azouz, Zouhour
2013-12-01
Automatic segmentation and 3D modeling of the knee joint from MR images, is a challenging task. Most of the existing techniques require the tedious manual segmentation of a training set of MRIs. We present an approach that necessitates the manual segmentation of one MR image. It is based on a volumetric active appearance model. First, a dense tetrahedral mesh is automatically created on a reference MR image that is arbitrary selected. Second, a pairwise non-rigid registration between each MRI from a training set and the reference MRI is computed. The non-rigid registration is based on a piece-wise affine deformation using the created tetrahedral mesh. The minimum description length is then used to bring all the MR images into a correspondence. An average image and tetrahedral mesh, as well as a set of main modes of variations, are generated using the established correspondence. Any manual segmentation of the average MRI can be mapped to other MR images using the AAM. The proposed approach has the advantage of simultaneously generating 3D reconstructions of the surface as well as a 3D solid model of the knee joint. The generated surfaces and tetrahedral meshes present the interesting property of fulfilling a correspondence between different MR images. This paper shows preliminary results of the proposed approach. It demonstrates the automatic segmentation and 3D reconstruction of a knee joint obtained by mapping a manual segmentation of a reference image.
An Approach to Automatic Generation of Test Cases Based on Use Cases in the Requirements Phase
Directory of Open Access Journals (Sweden)
U.Senthil Kumaran
2011-01-01
Full Text Available The main aim of this paper is to generate test cases from the use cases. In the real-time scenario we have to face several issues like inaccuracy, ambiguity, and incompleteness in requirements this is because the requirements are not properly updated after various change requests. This will reduce the quality of test cases. To overcome these problems we develop a solution which generates test cases at the early stages of system development life cycle which captures maximum number of requirements. As requirements are best captured by use cases our focus lies on generating test cases from use case diagrams.
Automatic generation of virtual worlds from architectural and mechanical CAD models
International Nuclear Information System (INIS)
Accelerator projects like the XFEL or the planned linear collider TESLA involve extensive architectural and mechanical design work, resulting in a variety of CAD models. The CAD models will be showing different parts of the project, like e.g. the different accelerator components or parts of the building complexes, and they will be created and stored by different groups in different formats. A complete CAD model of the accelerator and its buildings is thus difficult to obtain and would also be extremely huge and difficult to handle. This thesis describes the design and prototype development of a tool which automatically creates virtual worlds from different CAD models. The tool will enable the user to select a required area for visualization on a map, and then create a 3D-model of the selected area which can be displayed in a web-browser. The thesis first discusses the system requirements and provides some background on data visualization. Then, it introduces the system architecture, the algorithms and the used technologies, and finally demonstrates the capabilities of the system using two case studies. (orig.)
Akilan, A.; Nagasubramanian, V.; Chaudhry, A.; Reddy, D. Rajesh; Sudheer Reddy, D.; Usha Devi, R.; Tirupati, T.; Radhadevi, P. V.; Varadan, G.
2014-11-01
Block Adjustment is a technique for large area mapping for images obtained from different remote sensingsatellites.The challenge in this process is to handle huge number of satellite imageries from different sources with different resolution and accuracies at the system level. This paper explains a system with various tools and techniques to effectively handle the end-to-end chain in large area mapping and production with good level of automation and the provisions for intuitive analysis of final results in 3D and 2D environment. In addition, the interface for using open source ortho and DEM references viz., ETM, SRTM etc. and displaying ESRI shapes for the image foot-prints are explained. Rigorous theory, mathematical modelling, workflow automation and sophisticated software engineering tools are included to ensure high photogrammetric accuracy and productivity. Major building blocks like Georeferencing, Geo-capturing and Geo-Modelling tools included in the block adjustment solution are explained in this paper. To provide optimal bundle block adjustment solution with high precision results, the system has been optimized in many stages to exploit the full utilization of hardware resources. The robustness of the system is ensured by handling failure in automatic procedure and saving the process state in every stage for subsequent restoration from the point of interruption. The results obtained from various stages of the system are presented in the paper.
Dunne, Matthew J.
2011-01-01
The development of computer software as a tool to generate visual displays has led to an overall expansion of automated computer generated images in the aerospace industry. These visual overlays are generated by combining raw data with pre-existing data on the object or objects being analyzed on the screen. The National Aeronautics and Space Administration (NASA) uses this computer software to generate on-screen overlays when a Visiting Vehicle (VV) is berthing with the International Space Station (ISS). In order for Mission Control Center personnel to be a contributing factor in the VV berthing process, computer software similar to that on the ISS must be readily available on the ground to be used for analysis. In addition, this software must perform engineering calculations and save data for further analysis.
PGPG: An Automatic Generator of Pipeline Design for Programmable GRAPE Systems
Hamada, Tsuyoshi; Fukushige, Toshiyuki; Makino, Junichiro
2007-01-01
We have developed PGPG (Pipeline Generator for Programmable GRAPE), a software which generates the low-level design of the pipeline processor and communication software for FPGA-based computing engines (FBCEs). An FBCE typically consists of one or multiple FPGA (Field-Programmable Gate Array) chips and local memory. Here, the term "Field-Programmable" means that one can rewrite the logic implemented to the chip after the hardware is completed, and therefore a single FBCE can be used for calcu...
MOAB : a mesh-oriented database.
Energy Technology Data Exchange (ETDEWEB)
Tautges, Timothy James; Ernst, Corey; Stimpson, Clint; Meyers, Ray J.; Merkley, Karl
2004-04-01
A finite element mesh is used to decompose a continuous domain into a discretized representation. The finite element method solves PDEs on this mesh by modeling complex functions as a set of simple basis functions with coefficients at mesh vertices and prescribed continuity between elements. The mesh is one of the fundamental types of data linking the various tools in the FEA process (mesh generation, analysis, visualization, etc.). Thus, the representation of mesh data and operations on those data play a very important role in FEA-based simulations. MOAB is a component for representing and evaluating mesh data. MOAB can store structured and unstructured mesh, consisting of elements in the finite element 'zoo'. The functional interface to MOAB is simple yet powerful, allowing the representation of many types of metadata commonly found on the mesh. MOAB is optimized for efficiency in space and time, based on access to mesh in chunks rather than through individual entities, while also versatile enough to support individual entity access. The MOAB data model consists of a mesh interface instance, mesh entities (vertices and elements), sets, and tags. Entities are addressed through handles rather than pointers, to allow the underlying representation of an entity to change without changing the handle to that entity. Sets are arbitrary groupings of mesh entities and other sets. Sets also support parent/child relationships as a relation distinct from sets containing other sets. The directed-graph provided by set parent/child relationships is useful for modeling topological relations from a geometric model or other metadata. Tags are named data which can be assigned to the mesh as a whole, individual entities, or sets. Tags are a mechanism for attaching data to individual entities and sets are a mechanism for describing relations between entities; the combination of these two mechanisms is a powerful yet simple interface for representing metadata or application
On the Automatic Generation of Plans for Life Cycle Assembly Processes
Energy Technology Data Exchange (ETDEWEB)
CALTON,TERRI L.
2000-01-01
Designing products for easy assembly and disassembly during their entire life cycles for purposes including product assembly, product upgrade, product servicing and repair, and product disposal is a process that involves many disciplines. In addition, finding the best solution often involves considering the design as a whole and by considering its intended life cycle. Different goals and manufacturing plan selection criteria, as compared to initial assembly, require re-visiting significant fundamental assumptions and methods that underlie current assembly planning techniques. Previous work in this area has been limited to either academic studies of issues in assembly planning or to applied studies of life cycle assembly processes that give no attention to automatic planning. It is believed that merging these two areas will result in a much greater ability to design for, optimize, and analyze the cycle assembly processes. The study of assembly planning is at the very heart of manufacturing research facilities and academic engineering institutions; and, in recent years a number of significant advances in the field of assembly planning have been made. These advances have ranged from the development of automated assembly planning systems, such as Sandia's Automated Assembly Analysis System Archimedes 3.0{copyright}, to the startling revolution in microprocessors and computer-controlled production tools such as computer-aided design (CAD), computer-aided manufacturing (CAM), flexible manufacturing systems (EMS), and computer-integrated manufacturing (CIM). These results have kindled considerable interest in the study of algorithms for life cycle related assembly processes and have blossomed into a field of intense interest. The intent of this manuscript is to bring together the fundamental results in this area, so that the unifying principles and underlying concepts of algorithm design may more easily be implemented in practice.
Directory of Open Access Journals (Sweden)
SATHANS,
2011-05-01
Full Text Available This work proposes a Fuzzy Gain Scheduled Proportional-Integral (FGSPI controller for automatic generation control (AGC of two-equal area interconnected thermal power system including the Superconducting Magnetic Energy Storage (SMES unit in both areas. The reheat effect nonlinearity of the steam turbine is also consideredin this study. Simulation results show that the proposed control scheme with SMES is very effective in damping the frequency and tie-line power oscillations due to load perturbations in one of the areas. To further improve the performance of the controller, a new formulation of the area control error (ACE is also adopted. Theproposed FGSPI controller is compared against conventional PI controller and state feedback LQR controller using settling times, overshoots and undershoots of the power and frequency deviations as performance indices and the performance of the proposed controller is found better than the other two. Simulations have been performed using Matlab®.
Automatic generation of analogy questions for student assessment: an Ontology-based approach
Directory of Open Access Journals (Sweden)
Bijan Parsia
2012-08-01
Full Text Available Different computational models for generating analogies of the form “A is to B as C is to D” have been proposed over the past 35 years. However, analogy generation is a challenging problem that requires further research. In this article, we present a new approach for generating analogies in Multiple Choice Question (MCQ format that can be used for students’ assessment. We propose to use existing high-quality ontologies as a source for mining analogies to avoid the classic problem of hand-coding concepts in previous methods. We also describe the characteristics of a good analogy question and report on experiments carried out to evaluate the new approach.
Mesh deformation based on artificial neural networks
Stadler, Domen; Kosel, Franc; Čelič, Damjan; Lipej, Andrej
2011-09-01
In the article a new mesh deformation algorithm based on artificial neural networks is introduced. This method is a point-to-point method, meaning that it does not use connectivity information for calculation of the mesh deformation. Two already known point-to-point methods, based on interpolation techniques, are also presented. In contrast to the two known interpolation methods, the new method does not require a summation over all boundary nodes for one displacement calculation. The consequence of this fact is a shorter computational time of mesh deformation, which is proven by different deformation tests. The quality of the deformed meshes with all three deformation methods was also compared. Finally, the generated and the deformed three-dimensional meshes were used in the computational fluid dynamics numerical analysis of a Francis water turbine. A comparison of the analysis results was made to prove the applicability of the new method in every day computation.
Namiot, Dmitry
2015-01-01
With the advances in mobile computing technologies and the growth of the Net, mobile mesh networks are going through a set of important evolutionary steps. In this paper, we survey architectural aspects of mobile mesh networks and their use cases and deployment models. Also, we survey challenging areas of mobile mesh networks and describe our vision of promising mobile services. This paper presents a basic introductory material for Masters of Open Information Technologies Lab, interested in m...
MacLeod, Matthew K
2015-01-01
Analytical nuclear gradients for fully internally contracted complete active space second-order perturbation theory (CASPT2) are reported. This implementation has been realized by an automated code generator that can handle spin-free formulas for the CASPT2 energy and its derivatives with respect to variations of molecular orbitals and reference coefficients. The underlying complete active space self-consistent field and the so-called Z-vector equations are solved using density fitting. With full internal contraction the size of first-order wave functions scales polynomially with the number of active orbitals. The CASPT2 gradient program and the code generator are both publicly available. This work enables the CASPT2 geometry optimization of molecules as complex as those investigated by respective single-point calculations.
A rule-based expert system for automatic control rod pattern generation for boiling water reactors
International Nuclear Information System (INIS)
This paper reports on an expert system for generating control rod patterns that has been developed. The knowledge is transformed into IF-THEN rules. The inference engine uses the Rete pattern matching algorithm to match facts, and rule premises and conflict resolution strategies to make the system function intelligently. A forward-chaining mechanism is adopted in the inference engine. The system is implemented in the Common Lisp programming language. The three-dimensional core simulation model performs the core status and burnup calculations. The system is successfully demonstrated by generating control rod programming for the 2894-MW (thermal) Kuosheng nuclear power plant in Taiwan. The computing time is tremendously reduced compared to programs using mathematical methods
PGPG: An Automatic Generator of Pipeline Design for Programmable GRAPE Systems
Hamada, T; Makino, J; Hamada, Tsuyoshi; Fukushige, Toshiyuki; Makino, Junichiro
2007-01-01
We have developed PGPG (Pipeline Generator for Programmable GRAPE), a software which generates the low-level design of the pipeline processor and communication software for FPGA-based computing engines (FBCEs). An FBCE typically consists of one or multiple FPGA (Field-Programmable Gate Array) chips and local memory. Here, the term "Field-Programmable" means that one can rewrite the logic implemented to the chip after the hardware is completed, and therefore a single FBCE can be used for calculation of various functions, for example pipeline processors for gravity, SPH interaction, or image processing. The main problem with FBCEs is that the user need to develop the detailed hardware design for the processor to be implemented to FPGA chips. In addition, she or he has to write the control logic for the processor, communication and data conversion library on the host processor, and application program which uses the developed processor. These require detailed knowledge of hardware design, a hardware description ...
Automatic generation of synthesizable hardware implementation from high level RVC-cal description
Jerbi, Khaled; Raulet, Mickaël; Deforges, Olivier; Abid, Mohamed
2012-01-01
International audience Data process algorithms are increasing in complexity especially for image and video coding. Therefore, hardware development using directly hardware description languages (HDL) such as VHDL or Verilog is a difficult task. Current research axes in this context are introducing new methodologies to automate the generation of such descriptions. In our work we adopted a high level and target-independent language called CAL (Caltrop Actor Language). This language is associa...
A New Model for Automatic Generation of Plan Libraries for Plan Recognition
Marchetta, Martín G.; Raymundo Q. Forradellas
2010-01-01
In the context of Computer Aided Process Planning (CAPP), feature recognition as well as the generation of manufacturing process plans are very diffi cult problems. The selection of the best manufacturing process plan usually involves not only measurable factors, but also idiosyncrasies, preferences and the know-how of both the company and the manufacturing engineer. In this scenario, mixed-initiative techniques such as plan
recognition, where both human users and intelligent agent...
On-line multiobjective automatic control system generation by evolutionary algorithms
Stewart, Paul; Stone, D. A.; Fleming, P.A.
2006-01-01
Evolutionary algorithms are applied to the on- line generation of servo-motor control systems. In this paper, the evolving population of controllers is evaluated at run-time via hardware in the loop, rather than on a simulated model. Disturbances are also introduced at run-time in order to pro- duce robust performance. Multiobjective optimisation of both PI and Fuzzy Logic controllers is considered. Finally an on-line implementation of Genetic Programming is presented based around the Simulin...
GUDM: Automatic Generation of Unified Datasets for Learning and Reasoning in Healthcare
Directory of Open Access Journals (Sweden)
Rahman Ali
2015-07-01
Full Text Available A wide array of biomedical data are generated and made available to healthcare experts. However, due to the diverse nature of data, it is difficult to predict outcomes from it. It is therefore necessary to combine these diverse data sources into a single unified dataset. This paper proposes a global unified data model (GUDM to provide a global unified data structure for all data sources and generate a unified dataset by a “data modeler” tool. The proposed tool implements user-centric priority based approach which can easily resolve the problems of unified data modeling and overlapping attributes across multiple datasets. The tool is illustrated using sample diabetes mellitus data. The diverse data sources to generate the unified dataset for diabetes mellitus include clinical trial information, a social media interaction dataset and physical activity data collected using different sensors. To realize the significance of the unified dataset, we adopted a well-known rough set theory based rules creation process to create rules from the unified dataset. The evaluation of the tool on six different sets of locally created diverse datasets shows that the tool, on average, reduces 94.1% time efforts of the experts and knowledge engineer while creating unified datasets.
International Nuclear Information System (INIS)
Analytical nuclear gradients for fully internally contracted complete active space second-order perturbation theory (CASPT2) are reported. This implementation has been realized by an automated code generator that can handle spin-free formulas for the CASPT2 energy and its derivatives with respect to variations of molecular orbitals and reference coefficients. The underlying complete active space self-consistent field and the so-called Z-vector equations are solved using density fitting. The implementation has been applied to the vertical and adiabatic ionization potentials of the porphin molecule to illustrate its capability
MacLeod, Matthew K.; Shiozaki, Toru
2015-02-01
Analytical nuclear gradients for fully internally contracted complete active space second-order perturbation theory (CASPT2) are reported. This implementation has been realized by an automated code generator that can handle spin-free formulas for the CASPT2 energy and its derivatives with respect to variations of molecular orbitals and reference coefficients. The underlying complete active space self-consistent field and the so-called Z-vector equations are solved using density fitting. The implementation has been applied to the vertical and adiabatic ionization potentials of the porphin molecule to illustrate its capability.
MacLeod, Matthew K; Shiozaki, Toru
2015-02-01
Analytical nuclear gradients for fully internally contracted complete active space second-order perturbation theory (CASPT2) are reported. This implementation has been realized by an automated code generator that can handle spin-free formulas for the CASPT2 energy and its derivatives with respect to variations of molecular orbitals and reference coefficients. The underlying complete active space self-consistent field and the so-called Z-vector equations are solved using density fitting. The implementation has been applied to the vertical and adiabatic ionization potentials of the porphin molecule to illustrate its capability. PMID:25662628
GRACE/SUSY Automatic Generation of Tree Amplitudes in the Minimal Supersymmetric Standard Model
Fujimoto, J
2002-01-01
GRACE/SUSY is a program package for generating the tree-level amplitude and evaluating the corresponding cross section of processes of the minimal supersymmetric extension of the standard model (MSSM). The Higgs potential adopted in the system, however, is assumed to have a more general form indicated by the two-Higgs-doublet model. This system is an extension of GRACE for the standard model(SM) of the electroweak and strong interactions. For a given MSSM process the Feynman graphs and amplit...
Energy Technology Data Exchange (ETDEWEB)
Coimbra, Carlos F. M. [Univ. of California, San Diego, CA (United States
2016-02-25
In this project we address multiple resource integration challenges associated with increasing levels of solar penetration that arise from the variability and uncertainty in solar irradiance. We will model the SMUD service region as its own balancing region, and develop an integrated, real-time operational tool that takes solar-load forecast uncertainties into consideration and commits optimal energy resources and reserves for intra-hour and intra-day decisions. The primary objectives of this effort are to reduce power system operation cost by committing appropriate amount of energy resources and reserves, as well as to provide operators a prediction of the generation fleet’s behavior in real time for realistic PV penetration scenarios. The proposed methodology includes the following steps: clustering analysis on the expected solar variability per region for the SMUD system, Day-ahead (DA) and real-time (RT) load forecasts for the entire service areas, 1-year of intra-hour CPR forecasts for cluster centers, 1-year of smart re-forecasting CPR forecasts in real-time for determination of irreducible errors, and uncertainty quantification for integrated solar-load for both distributed and central stations (selected locations within service region) PV generation.
Automatic mechanism generation for pyrolysis of di-tert-butyl sulfide.
Class, Caleb A; Liu, Mengjie; Vandeputte, Aäron G; Green, William H
2016-08-01
The automated Reaction Mechanism Generator (RMG), using rate parameters derived from ab initio CCSD(T) calculations, is used to build reaction networks for the thermal decomposition of di-tert-butyl sulfide. Simulation results were compared with data from pyrolysis experiments with and without the addition of a cyclohexene inhibitor. Purely free-radical chemistry did not properly explain the reactivity of di-tert-butyl sulfide, as the previous experimental work showed that the sulfide decomposed via first-order kinetics in the presence and absence of the radical inhibitor. The concerted unimolecular decomposition of di-tert-butyl sulfide to form isobutene and tert-butyl thiol was found to be a key reaction in both cases, as it explained the first-order sulfide decomposition. The computer-generated kinetic model predictions quantitatively match most of the experimental data, but the model is apparently missing pathways for radical-induced decomposition of thiols to form elemental sulfur. Cyclohexene has a significant effect on the composition of the radical pool, and this led to dramatic changes in the resulting product distribution. PMID:27431650
Abayowa, Bernard O.; Yilmaz, Alper; Hardie, Russell C.
2015-08-01
This paper presents a framework for automatic registration of both the optical and 3D structural information extracted from oblique aerial imagery to a Light Detection and Ranging (LiDAR) point cloud without prior knowledge of an initial alignment. The framework employs a coarse to fine strategy in the estimation of the registration parameters. First, a dense 3D point cloud and the associated relative camera parameters are extracted from the optical aerial imagery using a state-of-the-art 3D reconstruction algorithm. Next, a digital surface model (DSM) is generated from both the LiDAR and the optical imagery-derived point clouds. Coarse registration parameters are then computed from salient features extracted from the LiDAR and optical imagery-derived DSMs. The registration parameters are further refined using the iterative closest point (ICP) algorithm to minimize global error between the registered point clouds. The novelty of the proposed approach is in the computation of salient features from the DSMs, and the selection of matching salient features using geometric invariants coupled with Normalized Cross Correlation (NCC) match validation. The feature extraction and matching process enables the automatic estimation of the coarse registration parameters required for initializing the fine registration process. The registration framework is tested on a simulated scene and aerial datasets acquired in real urban environments. Results demonstrates the robustness of the framework for registering optical and 3D structural information extracted from aerial imagery to a LiDAR point cloud, when co-existing initial registration parameters are unavailable.
朴素贝叶斯应用于自动化测试用例生成%Naive Bayesian Applied in Automatic Test Cases Generation
Institute of Scientific and Technical Information of China (English)
李欣; 张聪; 罗宪
2012-01-01
提出一种使用朴素贝叶斯作为核心算法来产生自动化测试用例的方法。该方法以实现自动化测试为目标,引入了朴素贝叶斯对产生的随机测试用例分类的思想。实验结果表明,这是一种可行的生成测试用例的方法。%Test cases generation was the key of automatic testing. Test cases generated great significance in software testing process. Automatic testing cases generated by as the core algorithm were presented in this paper. And the thoughts of classificatio in test case generation. The results showed the method presented in this paper was to generate test cases. effectively had Bayesian methods n were introduced a feasible method
Directory of Open Access Journals (Sweden)
Abdul Basit
2014-10-01
Full Text Available Transmission system operators have an increased interest in the active participation of wind power plants (WPP in the power balance control of power systems with large wind power penetration. The emphasis in this study is on the integration of WPPs into the automatic generation control (AGC of the power system. The present paper proposes a coordinated control strategy for the AGC between combined heat and power plants (CHPs and WPPs to enhance the security and the reliability of a power system operation in the case of a large wind power penetration. The proposed strategy, described and exemplified for the future Danish power system, takes the hour-ahead regulating power plan for generation and power exchange with neighbouring power systems into account. The performance of the proposed strategy for coordinated secondary control is assessed and discussed by means of simulations for different possible future scenarios, when wind power production in the power system is high and conventional production from CHPs is at a minimum level. The investigation results of the proposed control strategy have shown that the WPPs can actively help the AGC, and reduce the real-time power imbalance in the power system, by down regulating their production when CHPs are unable to provide the required response.
Performance of automatic generation control mechanisms with large-scale wind power
International Nuclear Information System (INIS)
The unpredictability and variability of wind power increasingly challenges real-time balancing of supply and demand in electric power systems. In liberalised markets, balancing is a responsibility jointly held by the TSO (real-time power balancing) and PRPs (energy programs). In this paper, a procedure is developed for the simulation of power system balancing and the assessment of AGC performance in the presence of large-scale wind power, using the Dutch control zone as a case study. The simulation results show that the performance of existing AGC-mechanisms is adequate for keeping ACE within acceptable bounds. At higher wind power penetrations, however, the capabilities of the generation mix are increasingly challenged and additional reserves are required at the same level. (au)
Automatic Multi-GPU Code Generation applied to Simulation of Electrical Machines
Rodrigues, Antonio Wendell De Oliveira; Dekeyser, Jean-Luc; Menach, Yvonnick Le
2011-01-01
The electrical and electronic engineering has used parallel programming to solve its large scale complex problems for performance reasons. However, as parallel programming requires a non-trivial distribution of tasks and data, developers find it hard to implement their applications effectively. Thus, in order to reduce design complexity, we propose an approach to generate code for hybrid architectures (e.g. CPU + GPU) using OpenCL, an open standard for parallel programming of heterogeneous systems. This approach is based on Model Driven Engineering (MDE) and the MARTE profile, standard proposed by Object Management Group (OMG). The aim is to provide resources to non-specialists in parallel programming to implement their applications. Moreover, thanks to model reuse capacity, we can add/change functionalities or the target architecture. Consequently, this approach helps industries to achieve their time-to-market constraints and confirms by experimental tests, performance improvements using multi-GPU environmen...
The efficiency of geophysical adjoint codes generated by automatic differentiation tools
Vlasenko, A. V.; Köhl, A.; Stammer, D.
2016-02-01
The accuracy of numerical models that describe complex physical or chemical processes depends on the choice of model parameters. Estimating an optimal set of parameters by optimization algorithms requires knowledge of the sensitivity of the process of interest to model parameters. Typically the sensitivity computation involves differentiation of the model, which can be performed by applying algorithmic differentiation (AD) tools to the underlying numerical code. However, existing AD tools differ substantially in design, legibility and computational efficiency. In this study we show that, for geophysical data assimilation problems of varying complexity, the performance of adjoint codes generated by the existing AD tools (i) Open_AD, (ii) Tapenade, (iii) NAGWare and (iv) Transformation of Algorithms in Fortran (TAF) can be vastly different. Based on simple test problems, we evaluate the efficiency of each AD tool with respect to computational speed, accuracy of the adjoint, the efficiency of memory usage, and the capability of each AD tool to handle modern FORTRAN 90-95 elements such as structures and pointers, which are new elements that either combine groups of variables or provide aliases to memory addresses, respectively. We show that, while operator overloading tools are the only ones suitable for modern codes written in object-oriented programming languages, their computational efficiency lags behind source transformation by orders of magnitude, rendering the application of these modern tools to practical assimilation problems prohibitive. In contrast, the application of source transformation tools appears to be the most efficient choice, allowing handling even large geophysical data assimilation problems. However, they can only be applied to numerical models written in earlier generations of programming languages. Our study indicates that applying existing AD tools to realistic geophysical problems faces limitations that urgently need to be solved to allow the
Directory of Open Access Journals (Sweden)
G. T. Kulakov
2014-01-01
Full Text Available The paper analyzes an operation of the standard three-impulse automatic control system (ACS for steam generator water supply. Mathematical model for checking its operational ability on load relief has been developed in the paper and this model makes it possible to determine maximum deviations of water level without execution of actual tests and any corrections in the plants for starting-up of technological protection systems in accordance with water level in the drum. The paper reveals reasons of static regulation errors while solving problems of internal and external distortions caused by expenditure of over-heated steam in the standard automatic control system. An actual significance of modernization pertaining to automatic control system for steam generator water supply has been substantiated in the paper.
International Nuclear Information System (INIS)
DISIGEG is a synthesis installation of zirconium 99Mo-molybdate gels for 99Mo/99mTc generator production, which has been designed, built and installed at the ININ. The device consists of a synthesis reactor and five systems controlled via keyboard: (1) raw material access, (2) chemical air stirring, (3) gel dried by air and infrared heating, (4) moisture removal and (5) gel extraction. DISIGEG operation is described and dried condition effects of zirconium 99Mo- molybdate gels on 99Mo/99mTc generator performance were evaluated as well as some physical–chemical properties of these gels. The results reveal that temperature, time and air flow applied during the drying process directly affects zirconium 99Mo-molybdate gel generator performance. All gels prepared have a similar chemical structure probably constituted by three-dimensional network, based on zirconium pentagonal bipyramids and molybdenum octahedral. Basic structural variations cause a change in gel porosity and permeability, favouring or inhibiting 99mTcO4− diffusion into the matrix. The 99mTcO4− eluates produced by 99Mo/99mTc zirconium 99Mo-molybdate gel generators prepared in DISIGEG, air dried at 80 °C for 5 h and using an air flow of 90 mm, satisfied all the Pharmacopoeias regulations: 99mTc yield between 70–75%, 99Mo breakthrough less than 3×10−3%, radiochemical purities about 97% sterile and pyrogen-free eluates with a pH of 6. - Highlights: ► 99Mo/99mTc generators based on 99Mo-molybdate gels were synthesized at a semi-automatic device. ► Generator performances depend on synthesis conditions of the zirconium 99Mo-molybdate gel. ► 99mTcO4− diffusion and yield into generator depends on gel porosity and permeability. ► 99mTcO4− eluates satisfy Pharmacopoeias regulations and can be applied for clinical use.
Pertel, Michael J.
1992-01-01
A table of useful summation formulae are derived, together with a Mathematica package for producing them. The distance distribution in mesh routing networks is derived. The mean and variance of the distance distribution are computed. A program for computing the distance distribution of any mesh is presented.
An Adaptive Mesh Algorithm: Mapping the Mesh Variables
Energy Technology Data Exchange (ETDEWEB)
Scannapieco, Anthony J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-07-25
Both thermodynamic and kinematic variables must be mapped. The kinematic variables are defined on a separate kinematic mesh; it is the duel mesh to the thermodynamic mesh. The map of the kinematic variables is done by calculating the contributions of kinematic variables on the old thermodynamic mesh, mapping the kinematic variable contributions onto the new thermodynamic mesh and then synthesizing the mapped kinematic variables on the new kinematic mesh. In this document the map of the thermodynamic variables will be described.
LOAD AWARE ADAPTIVE BACKBONE SYNTHESIS IN WIRELESS MESH NETWORKS
Institute of Scientific and Technical Information of China (English)
Yuan Yuan; Zheng Baoyu
2009-01-01
Wireless Mesh Networks (WMNs) are envisioned to support the wired backbone with a wireless Backbone Networks (BNet) for providing internet connectivity to large-scale areas.With a wide range of internet-oriented applications with different Quality of Service (QoS) requirement,the large-scale WMNs should have good scalability and large bandwidth.In this paper,a Load Aware Adaptive Backbone Synthesis (LAABS) algorithm is proposed to automatically balance the traffic flow in the WMNs.The BNet will dynamically split into smaller size or merge into bigger one according to statistic load information of Backbone Nodes (BNs).Simulation results show LAABS generates moderate BNet size and converges quickly,thus providing scalable and stable BNet to facilitate traffic flow.
Gamra: Simple Meshes for Complex Earthquakes
Landry, Walter; Barbot, Sylvain
2016-01-01
The static offsets caused by earthquakes are well described by elastostatic models with a discontinuity in the displacement along the fault. A traditional approach to model this discontinuity is to align the numerical mesh with the fault and solve the equations using finite elements. However, this distorted mesh can be difficult to generate and update. We present a new numerical method, inspired by the Immersed Interface Method, for solving the elastostatic equations with embedded discontinui...
Directory of Open Access Journals (Sweden)
Rabindra Kumar Sahu
2016-03-01
Full Text Available This paper presents the design and analysis of Proportional-Integral-Double Derivative (PIDD controller for Automatic Generation Control (AGC of multi-area power systems with diverse energy sources using Teaching Learning Based Optimization (TLBO algorithm. At first, a two-area reheat thermal power system with appropriate Generation Rate Constraint (GRC is considered. The design problem is formulated as an optimization problem and TLBO is employed to optimize the parameters of the PIDD controller. The superiority of the proposed TLBO based PIDD controller has been demonstrated by comparing the results with recently published optimization technique such as hybrid Firefly Algorithm and Pattern Search (hFA-PS, Firefly Algorithm (FA, Bacteria Foraging Optimization Algorithm (BFOA, Genetic Algorithm (GA and conventional Ziegler Nichols (ZN for the same interconnected power system. Also, the proposed approach has been extended to two-area power system with diverse sources of generation like thermal, hydro, wind and diesel units. The system model includes boiler dynamics, GRC and Governor Dead Band (GDB non-linearity. It is observed from simulation results that the performance of the proposed approach provides better dynamic responses by comparing the results with recently published in the literature. Further, the study is extended to a three unequal-area thermal power system with different controllers in each area and the results are compared with published FA optimized PID controller for the same system under study. Finally, sensitivity analysis is performed by varying the system parameters and operating load conditions in the range of ±25% from their nominal values to test the robustness.
21st International Meshing Roundtable
Weill, Jean-Christophe
2013-01-01
This volume contains the articles presented at the 21st International Meshing Roundtable (IMR) organized, in part, by Sandia National Laboratories and was held on October 7–10, 2012 in San Jose, CA, USA. The first IMR was held in 1992, and the conference series has been held annually since. Each year the IMR brings together researchers, developers, and application experts in a variety of disciplines, from all over the world, to present and discuss ideas on mesh generation and related topics. The technical papers in this volume present theoretical and novel ideas and algorithms with practical potential, as well as technical applications in science and engineering, geometric modeling, computer graphics, and visualization.
22nd International Meshing Roundtable
Staten, Matthew
2014-01-01
This volume contains the articles presented at the 22nd International Meshing Roundtable (IMR) organized, in part, by Sandia National Laboratories and was held on Oct 13-16, 2013 in Orlando, Florida, USA. The first IMR was held in 1992, and the conference series has been held annually since. Each year the IMR brings together researchers, developers, and application experts in a variety of disciplines, from all over the world, to present and discuss ideas on mesh generation and related topics. The technical papers in this volume present theoretical and novel ideas and algorithms with practical potential, as well as technical applications in science and engineering, geometric modeling, computer graphics and visualization.
Numerical modeling of seismic waves using frequency-adaptive meshes
Hu, Jinyin; Jia, Xiaofeng
2016-08-01
An improved modeling algorithm using frequency-adaptive meshes is applied to meet the computational requirements of all seismic frequency components. It automatically adopts coarse meshes for low-frequency computations and fine meshes for high-frequency computations. The grid intervals are adaptively calculated based on a smooth inversely proportional function of grid size with respect to the frequency. In regular grid-based methods, the uniform mesh or non-uniform mesh is used for frequency-domain wave propagators and it is fixed for all frequencies. A too coarse mesh results in inaccurate high-frequency wavefields and unacceptable numerical dispersion; on the other hand, an overly fine mesh may cause storage and computational overburdens as well as invalid propagation angles of low-frequency wavefields. Experiments on the Padé generalized screen propagator indicate that the Adaptive mesh effectively solves these drawbacks of regular fixed-mesh methods, thus accurately computing the wavefield and its propagation angle in a wide frequency band. Several synthetic examples also demonstrate its feasibility for seismic modeling and migration.
International Nuclear Information System (INIS)
The automatization of the monitoring of the steam generator tubes required some developments in the field of data processing. The monitoring is performed by means of Eddy current tests. Improvements in signal processing and in pattern recognition associated to the artificial intelligence techniques induced EDF (French Electricity Company) to develop an automatic signal processing system. The system, named EXTRACSION (French acronym for Expert System for the Processing and classification of Signals of Nuclear Nature), insures the coherence between the different fields of knowledge (metallurgy, measurement, signals) during data processing by applying an object oriented representation
Directory of Open Access Journals (Sweden)
Janardan Nanda
2015-05-01
Full Text Available This study presents automatic generation control (AGC of interconnected power systems comprising of two thermal and one hydro area having integral controllers. Emphasis is given to a delay in the area control error for the actuation of the supplementary controller and to examine its impact on the dynamic response against no delay which is usually the practice. Analysis is based on 50% loading condition in all the areas. The system performance is examined considering 1% step load perturbation. Results reveal that delayed mode operation provides a better system dynamic performance compared with that obtained without delay and has several distinct merits for the governor. The delay is linked with reduction in wear and tear of the secondary controller and hence increases the life of the governor. The controller gains are optimised by particle swarm optimisation. The performance of delayed mode operation of AGC at other loading conditions is also analysed. An attempt has also been made to find the impact of weights for different components in a cost function used to optimise the controller gains. A modified cost function having different weights for different components when used for controller gain optimisation improves the system performance.
Open64的MPI代码自动生成算法%Automatic Code Generation Algorithm of Open64 for MPI
Institute of Scientific and Technical Information of China (English)
向阳霞; 裴宏; 张惠民; 陈曼青
2011-01-01
针对开源编译器Open64存在MPI不能自动并行化的问题,对Open64中面向Cluster的MPI代码自动生成进行了研究。分析了MPI代码自动生成模块在Open64体系结构中的位置,提出了基于Open64的MPI代码自动生成算法,并对其进行了实验验证。实验结果表明：该算法不但能够有效降低MPI并行程序的通信开销,而且能够明显提高其加速比。%The MPI automatic code generation for Cluster based on Open64 is studied in relation to the problem that the open source compiler Open64 has no MPI automatic parallelizing function.Firstly,the location of MPI code automatic generation in the Open64 compiler architecture is analyzed,and then an Open64-based automatic generation algorithm for MPI code is presented,finally the experiments of testing the NPB benchmarks is conducted.The experimental results show that the algorithm can reduce communication overheads of MPI parallel programs effectively and increase their speedups obviously.
Effects of mesh style and grid convergence on numerical simulation accuracy of centrifugal pump
Institute of Scientific and Technical Information of China (English)
刘厚林; 刘明明; 白羽; 董亮
2015-01-01
In order to evaluate the effects of mesh generation techniques and grid convergence on pump performance in centrifugal pump model, three widely used mesh styles including structured hexahedral, unstructured tetrahedral and hybrid prismatic/tetrahedral meshes were generated for a centrifugal pump model. And quantitative grid convergence was assessed based on a grid convergence index (GCI), which accounts for the degree of grid refinement. The structured, unstructured or hybrid meshes are found to have certain difference for velocity distributions in impeller with the change of grid cell number. And the simulation results have errors to different degrees compared with experimental data. The GCI-value for structured meshes calculated is lower than that for the unstructured and hybrid meshes. Meanwhile, the structured meshes are observed to get more vortexes in impeller passage. Nevertheless, the hybrid meshes are found to have larger low-velocity area at outlet and more secondary vortexes at a specified location than structured meshes and unstructured meshes.
Urogynecologic Surgical Mesh Implants
... be used for urogynecologic procedures, including repair of pelvic organ prolapse (POP) and stress urinary incontinence (SUI). It is ... associated with surgical mesh for transvaginal repair of pelvic organ prolapse 513(e) Proposed Order for Reclassification of Surgical ...
Intelligent automatic generation control
Bevrani, Hassan
2011-01-01
""I enjoyed reading the book and found it informative. It is certainly a book I would recommend to postgraduate students and researchers in the area of intelligent control systems and their application to power system control. My congratulations to the authors.""-Pouyan Pourbeik, IEEE Power and Energy Magazine
Geometrically Consistent Mesh Modification
Bonito, A.
2010-01-01
A new paradigm of adaptivity is to execute refinement, coarsening, and smoothing of meshes on manifolds with incomplete information about their geometry and yet preserve position and curvature accuracy. We refer to this collectively as geometrically consistent (GC) mesh modification. We discuss the concept of discrete GC, show the failure of naive approaches, and propose and analyze a simple algorithm that is GC and accuracy preserving. © 2010 Society for Industrial and Applied Mathematics.
Botsch, Mario; Pauly, Mark; Alliez, Pierre; Levy, Bruno
2010-01-01
Geometry processing, or mesh processing, is a fast-growing area of research that uses concepts from applied mathematics, computer science, and engineering to design efficient algorithms for the acquisition, reconstruction, analysis, manipulation, simulation, and transmission of complex 3D models. Applications of geometry processing algorithms already cover a wide range of areas from multimedia, entertainment, and classical computer-aided design, to biomedical computing, reverse engineering, and scientific computing. Over the last several years, triangle meshes have become increasingly popular,
Provenier, F; Jordaens, L; Verstraeten, T; Clement, D L
1994-11-01
Automatic mode switch (AMS) from DDDR to VVIR pacing is a new algorithm, in response to paroxysmal atrial tachyarrhythmias. With the 5603 Programmer, the AMS in the Meta DDDR 1250 and 1250H (Telectronics Pacings Systems, Inc.) operates when VA is shorter than the adaptable PVARP. With the 9600 Programmer, an atrial protection interval can be defined after the PVARP. The latest generation, Meta DDDR 1254, initiates AMS when 5 or 11 heart cycles are > 150, 175, or 200 beats/min. From 1990 to 1993, 61 patients, mean age 61 years, received a Meta DDDR: in 24 a 1250, in 12 a 1250H and in the remaining 25 a 1254 model. Indication for pacing was heart block in 39, sick sinus syndrome in 15, the combination in 6, and hypertrophic obstructive cardiomyopathy in 1. Paroxysmal atrial tachyarrhythmias were present in 43. All patients had routine pacemaker surveillance, including 52 Holter recordings. In 32 patients, periods of atrial tachyarrhythmias were observed, with proper AMS to VVIR, except during short periods of 2:1 block for atrial flutter in 4. In two others, undersensing of the atrial arrhythmia disturbed correct AMS. With the 1250 and 1250H model, AMS was observed on several occasions during sinus rate accelerations in ten patients. This was never seen with the 1254 devices. Final programmation was VVIR in 2 (chronic atrial fibrillation), AAI in 1 (fracture of the ventricular lead), VDDR in 1 (atrial pacing during atrial fibrillation), DDD in 5, and DDDR in 53, 48 of whom had AMS programmed on.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7845791
CAD and mesh repair with Radial Basis Functions
Marchandise, E.; Piret, C.; Remacle, J.-F.
2012-03-01
In this paper we present a process that includes both model/mesh repair and mesh generation. The repair algorithm is based on an initial mesh that may be either an initial mesh of a dirty CAD model or STL triangulation with many errors such as gaps, overlaps and T-junctions. This initial mesh is then remeshed by computing a discrete parametrization with Radial Basis Functions (RBF's). We showed in [1] that a discrete parametrization can be computed by solving Partial Differential Equations (PDE's) on an initial correct mesh using finite elements. Paradoxically, the meshless character of the RBF's makes it an attractive numerical method for solving the PDE's for the parametrization in the case where the initial mesh contains errors or holes. In this work, we implement the Orthogonal Gradients method to be described in [2], as a RBF solution method for solving PDE's on arbitrary surfaces. Different examples show that the presented method is able to deal with errors such as gaps, overlaps, T-junctions and that the resulting meshes are of high quality. Moreover, the presented algorithm can be used as a hole-filling algorithm to repair meshes with undesirable holes. The overall procedure is implemented in the open-source mesh generator Gmsh [3].
Energy Technology Data Exchange (ETDEWEB)
Caballero Ortiz, Ezequiel
2002-12-01
This work is devoted to the analysis of the Automatic Control of Electrical Systems Generation of power, as of the information that generates the loop with Load-Frequency Control and the Automatic Voltage Regulator loop. To accomplish the analysis, the control classical theory and feedback control systems concepts are applied. Thus also, the modern theory concepts are employed. The studies are accomplished in the digital computer through the MATLAB program and the available simulation technique in the SIMULINK tool. In this thesis the theoretical and physical concepts of the automatic control of generation are established; dividing it in load frequency control and automatic voltage regulator loops. The mathematical models of the two control loops are established. Later, the models of the elements are interconnected in order to integrate the loop with load frequency control and the digital simulation of the system is carried out. In first instance, the function of the primary control in are - machine, area - multi machine and multi area - multi machine power systems, is analyzed. Then, the automatic control of generation of the area and multi area power systems is studied. The economic dispatch concept is established and with this plan the power system multi area is simulated, there in after the energy exchange among areas in stationary stage is studied. The mathematical models of the component elements of the control loop of the automatic voltage regulator are interconnected. Data according to the nature of each component are generated and their behavior is simulated to analyze the system response. The two control loops are interconnected and a simulation is carry out with data generated previously, examining the performance of the automatic control of generation and the interaction between the two control loops. Finally, the Poles Positioning and the Optimum Control techniques of the modern control theory are applied to the automatic control of an area generation
Silhouette smoothing for real-time rendering of mesh surfaces
Wang, L.; Tu, C.; W. Wang; Meng, X.; Chan, B; Yan, D.
2008-01-01
Coarse piecewise linear approximation of surfaces causes undesirable polygonal appearance of silhouettes. We present an efficient method for smoothing the silhouettes of coarse triangle meshes using efficient 3D curve reconstruction and simple local re-meshing. It does not assume the availability of a fine mesh and generates only moderate amount of additional data at run time. Furthermore, polygonal feature edges are also smoothed in a unified framework. Our method is based on a novel interpo...
An Anonymous Authentication and Communication Protocol for Wireless Mesh Networks
Sen, Jaydip
2011-01-01
Wireless mesh networks (WMNs) have emerged as a key technology for next generation wireless broadband networks showing rapid progress and inspiring numerous compelling applications. A WMN comprises of a set of mesh routers (MRs) and mesh clients (MCs), where MRs are connected to the Internet backbone through the Internet gateways (IGWs). The MCs are wireless devices and communicate among themselves over possibly multi-hop paths with or without the involvement of MRs. User privacy and security...
An Efficient Bandwidth Estimation Schemes used in Wireless Mesh Networks
A.Sandeep Kumar ,Second Author
2012-01-01
wireless mesh networks (WMNs) has been widely used for the new generation wireless network. The capability of self-organization in WMNs reduces the complexity of wireless network deployment and maintenance. So, the perfect estimation of the bandwidth available of the mesh nodes is the required to admission control mechanism which provides QOs confirmation in wireless mesh networks. The bandwidth estimation of schemes do not give clear output. Here we are proposing bandwidth scheme estimation ...
Conversion of Performance Mesh Animation into Cage-based Animation
Savoye, Yann; Franco, Jean-Sébastien
2010-01-01
Markerless highly-detailed performance capture is an emerging technology in vision-based graphics and 3D video. For instance, a framework for generating mesh animations from multi-view silhouettes is presented in [Vlasic et al. 2008]. Achieving inverse animation by approximating dynamic mesh using rigid skinning has inspired researchers to convert video-based reconstructed mesh sequence into rigid kinematic parameters as seen in [de Aguiar et al. 2008]. In contrast with previous techniques us...
William Barragán Zaque; Alexander Martínez Rivillas; Pablo Emilio Garzón Carreño
2015-01-01
The aim of this paper is to generate photogrammetrie products and to automatically map buildings in the area of interest in vector format. The research was conducted Bogotá using high resolution digital vertical aerial photographs and point clouds obtained using LIDAR technology. Image segmentation was also used, alongside radiometric and geometric digital processes. The process took into account aspects including building height, segmentation algorithms, and spectral band combination. The re...
International Nuclear Information System (INIS)
Highlights: • We implemented a fine-mesh coupled neutronic/thermal–hydraulic tool. • A CFD approach is used together with the multi-group neutron diffusion approximation. • Temperature-dependent cross-sections are generated with a Monte Carlo method. • We applied the tool to a simplified PWR fuel assembly. • Discrepancies in multiplication factor are seen against radial coarse-mesh averaging. - Abstract: This paper investigates the feasibility of developing a fine mesh coupled neutronic/thermal–hydraulic solver within the same computing platform for selected fuel assemblies in nuclear cores. As a first step in this developmental work, a Pressurized Water Reactor at steady-state conditions was considered. The system being simulated has a finite axial size, but is infinite in the radial direction. The platform used for the modeling is based on the open source C++ library OpenFOAM. The thermal–hydraulics is solved using the built-in SIMPLE algorithm for the mass and momentum fields of the fluid, complemented by an equation for the temperature field applied simultaneously to all the regions (i.e. fluid and solid structures). For the neutronics, a two-group neutron diffusion-based solver was developed, with sets of macroscopic cross-sections generated by the Monte Carlo code SERPENT. The meshing of the system was created by the open source software SALOME. Successful convergence of the neutronic and thermal–hydraulic fields was achieved, thus bringing the solution of the coupled problem to an unprecedented level of details. Most importantly, the true interdependence of the different fields is automatically guaranteed at all scales. In addition, comparisons with a coarse-mesh radial averaging of the thermal–hydraulic variables show that a coarse-mesh fuel temperature identical for all fuel pins can lead to discrepancies of up to 0.5% in pin powers, and of several tens of pcm in multiplication factor
Wang, Yibing; Breedveld, Sebastiaan; Heijmen, Ben; Petit, Steven F.
2016-06-01
IMRT planning with commercial Treatment Planning Systems (TPSs) is a trial-and-error process. Consequently, the quality of treatment plans may not be consistent among patients, planners and institutions. Recently, different plan quality assurance (QA) models have been proposed, that could flag and guide improvement of suboptimal treatment plans. However, the performance of these models was validated using plans that were created using the conventional trail-and-error treatment planning process. Consequently, it is challenging to assess and compare quantitatively the accuracy of different treatment planning QA models. Therefore, we created a golden standard dataset of consistently planned Pareto-optimal IMRT plans for 115 prostate patients. Next, the dataset was used to assess the performance of a treatment planning QA model that uses the overlap volume histogram (OVH). 115 prostate IMRT plans were fully automatically planned using our in-house developed TPS Erasmus-iCycle. An existing OVH model was trained on the plans of 58 of the patients. Next it was applied to predict DVHs of the rectum, bladder and anus of the remaining 57 patients. The predictions were compared with the achieved values of the golden standard plans for the rectum D mean, V 65, and V 75, and D mean of the anus and the bladder. For the rectum, the prediction errors (predicted–achieved) were only ‑0.2 ± 0.9 Gy (mean ± 1 SD) for D mean,‑1.0 ± 1.6% for V 65, and ‑0.4 ± 1.1% for V 75. For D mean of the anus and the bladder, the prediction error was 0.1 ± 1.6 Gy and 4.8 ± 4.1 Gy, respectively. Increasing the training cohort to 114 patients only led to minor improvements. A dataset of consistently planned Pareto-optimal prostate IMRT plans was generated. This dataset can be used to train new, and validate and compare existing treatment planning QA models, and has been made publicly available. The OVH model was highly
Wang, Yibing; Breedveld, Sebastiaan; Heijmen, Ben; Petit, Steven F
2016-06-01
IMRT planning with commercial Treatment Planning Systems (TPSs) is a trial-and-error process. Consequently, the quality of treatment plans may not be consistent among patients, planners and institutions. Recently, different plan quality assurance (QA) models have been proposed, that could flag and guide improvement of suboptimal treatment plans. However, the performance of these models was validated using plans that were created using the conventional trail-and-error treatment planning process. Consequently, it is challenging to assess and compare quantitatively the accuracy of different treatment planning QA models. Therefore, we created a golden standard dataset of consistently planned Pareto-optimal IMRT plans for 115 prostate patients. Next, the dataset was used to assess the performance of a treatment planning QA model that uses the overlap volume histogram (OVH). 115 prostate IMRT plans were fully automatically planned using our in-house developed TPS Erasmus-iCycle. An existing OVH model was trained on the plans of 58 of the patients. Next it was applied to predict DVHs of the rectum, bladder and anus of the remaining 57 patients. The predictions were compared with the achieved values of the golden standard plans for the rectum D mean, V 65, and V 75, and D mean of the anus and the bladder. For the rectum, the prediction errors (predicted-achieved) were only -0.2 ± 0.9 Gy (mean ± 1 SD) for D mean,-1.0 ± 1.6% for V 65, and -0.4 ± 1.1% for V 75. For D mean of the anus and the bladder, the prediction error was 0.1 ± 1.6 Gy and 4.8 ± 4.1 Gy, respectively. Increasing the training cohort to 114 patients only led to minor improvements. A dataset of consistently planned Pareto-optimal prostate IMRT plans was generated. This dataset can be used to train new, and validate and compare existing treatment planning QA models, and has been made publicly available. The OVH model was highly accurate
Garrett, S. J.; Bowers, J. C.; Oreilly, J. E., Jr.
1978-01-01
A computer program, PROSE, that produces nonlinear state equations from a simple topological description of an electrical or mechanical network is described. Unnecessary states are also automatically eliminated, so that a simplified terminal circuit model is obtained. The program also prints out the eigenvalues of a linearized system and the sensitivities of the eigenvalue of largest magnitude.
A semi-automatic computer-aided method for surgical template design
Chen, Xiaojun; Xu, Lu; Yang, Yue; Egger, Jan
2016-02-01
This paper presents a generalized integrated framework of semi-automatic surgical template design. Several algorithms were implemented including the mesh segmentation, offset surface generation, collision detection, ruled surface generation, etc., and a special software named TemDesigner was developed. With a simple user interface, a customized template can be semi- automatically designed according to the preoperative plan. Firstly, mesh segmentation with signed scalar of vertex is utilized to partition the inner surface from the input surface mesh based on the indicated point loop. Then, the offset surface of the inner surface is obtained through contouring the distance field of the inner surface, and segmented to generate the outer surface. Ruled surface is employed to connect inner and outer surfaces. Finally, drilling tubes are generated according to the preoperative plan through collision detection and merging. It has been applied to the template design for various kinds of surgeries, including oral implantology, cervical pedicle screw insertion, iliosacral screw insertion and osteotomy, demonstrating the efficiency, functionality and generality of our method.
Mesh quality improvement for SciDAC applications
International Nuclear Information System (INIS)
Accurate and efficient numerical solution of partial differential equations requires well-formed meshes that are non-inverted, smooth, well-shaped, oriented, and size-adapted. The Mesquite mesh quality improvement toolkit is a software library that applies optimization algorithms to create well-formed meshes via node movement. Mesquite can be run standalone using drivers or called directly from an application code. Mesquite can play an essential role in the SLAC accelerator design program as a component in automatic shape optimization software and in manufacturing defect-correction studies to smoothly deform meshes in response to geometric domain deformations guided by the optimization of design parameters. Mesquite has also been applied to problems in fusion, biology, and propellant burn studies
MeshVoro: A Three-Dimensional Voronoi Mesh Building Tool for the TOUGH Family of Codes
Energy Technology Data Exchange (ETDEWEB)
Freeman, C. M.; Boyle, K. L.; Reagan, M.; Johnson, J.; Rycroft, C.; Moridis, G. J.
2013-09-30
Few tools exist for creating and visualizing complex three-dimensional simulation meshes, and these have limitations that restrict their application to particular geometries and circumstances. Mesh generation needs to trend toward ever more general applications. To that end, we have developed MeshVoro, a tool that is based on the Voro (Rycroft 2009) library and is capable of generating complex threedimensional Voronoi tessellation-based (unstructured) meshes for the solution of problems of flow and transport in subsurface geologic media that are addressed by the TOUGH (Pruess et al. 1999) family of codes. MeshVoro, which includes built-in data visualization routines, is a particularly useful tool because it extends the applicability of the TOUGH family of codes by enabling the scientifically robust and relatively easy discretization of systems with challenging 3D geometries. We describe several applications of MeshVoro. We illustrate the ability of the tool to straightforwardly transform a complex geological grid into a simulation mesh that conforms to the specifications of the TOUGH family of codes. We demonstrate how MeshVoro can describe complex system geometries with a relatively small number of grid blocks, and we construct meshes for geometries that would have been practically intractable with a standard Cartesian grid approach. We also discuss the limitations and appropriate applications of this new technology.
GRChombo: Numerical relativity with adaptive mesh refinement
Clough, Katy; Figueras, Pau; Finkel, Hal; Kunesch, Markus; Lim, Eugene A.; Tunyasuvunakool, Saran
2015-12-01
In this work, we introduce {\\mathtt{GRChombo}}: a new numerical relativity code which incorporates full adaptive mesh refinement (AMR) using block structured Berger-Rigoutsos grid generation. The code supports non-trivial 'many-boxes-in-many-boxes' mesh hierarchies and massive parallelism through the message passing interface. {\\mathtt{GRChombo}} evolves the Einstein equation using the standard BSSN formalism, with an option to turn on CCZ4 constraint damping if required. The AMR capability permits the study of a range of new physics which has previously been computationally infeasible in a full 3 + 1 setting, while also significantly simplifying the process of setting up the mesh for these problems. We show that {\\mathtt{GRChombo}} can stably and accurately evolve standard spacetimes such as binary black hole mergers and scalar collapses into black holes, demonstrate the performance characteristics of our code, and discuss various physics problems which stand to benefit from the AMR technique.
Ontology-based tolerance specification generated automatically%基于本体的公差规范的自动生成
Institute of Scientific and Technical Information of China (English)
钟艳如; 王冰清; 覃裕初; 高文祥
2016-01-01
针对目前公差规范依靠人工指定带来不确定性的问题,在基于本体的公差类型自动生成方法的基础上,研究基于本体的公差规范的自动生成.通过分析公差规范领域知识,提取其中涉及的概念和关系,以此构建公差规范本体,并采用Web本体语言(Web Ontology Language,OWL)编码实现该本体.在所实现本体的基础上,采用语义Web规则语言(Semantic Web Rule Language,SWRL)定义公差规范的生成规则,进而设计公差规范的自动生成算法.应用所设计算法,说明减速器中间传动轴的公差规范自动生成的过程.将为CAD系统中公差规范自动生成的研究提供有效的思路和方法.%To reduce the uncertainty in the current tolerance specification relying on artificial, the ontology-based toler-ance specification generated automatically is studied based on automatic generation methodology of assembly tolerance types on ontology. In order to implement this ontology tolerance specification, the related concepts and relationships are analysed and the OWL(Web Ontology Language)is used to code. On the base of the ontology which is implemented, the automatic generation algorithm of tolerance specification is designed, using the SWRL(Semantic Web Rule Language)to define the generating rules. Using this algorithm, the procedure is illustrated by intermediate office propeller shaft of the reducer. The effective ideas and methods will be provided for the study of tolerance specification generated automatically for the CAD system.
The Numerical Simulation of Ship Waves Using Cartesian Grid Methods with Adaptive Mesh Refinement
Dommermuth, Douglas G; Beck, Robert F; O'Shea, Thomas T; Wyatt, Donald C; Olson, Kevin; MacNeice, Peter
2014-01-01
Cartesian-grid methods with Adaptive Mesh Refinement (AMR) are ideally suited for simulating the breaking of waves, the formation of spray, and the entrainment of air around ships. As a result of the cartesian-grid formulation, minimal input is required to describe the ships geometry. A surface panelization of the ship hull is used as input to automatically generate a three-dimensional model. No three-dimensional gridding is required. The AMR portion of the numerical algorithm automatically clusters grid points near the ship in regions where wave breaking, spray formation, and air entrainment occur. Away from the ship, where the flow is less turbulent, the mesh is coarser. The numerical computations are implemented using parallel algorithms. Together, the ease of input and usage, the ability to resolve complex free-surface phenomena, and the speed of the numerical algorithms provide a robust capability for simulating the free-surface disturbances near a ship. Here, numerical predictions, with and without AMR,...
Directory of Open Access Journals (Sweden)
Mohammad Awrangjeb
2015-10-01
Full Text Available Periodic building change detection is important for many applications, including disaster management. Building map databases need to be updated based on detected changes so as to ensure their currency and usefulness. This paper first presents a graphical user interface (GUI developed to support the creation of a building database from building footprints automatically extracted from LiDAR (light detection and ranging point cloud data. An automatic building change detection technique by which buildings are automatically extracted from newly-available LiDAR point cloud data and compared to those within an existing building database is then presented. Buildings identified as totally new or demolished are directly added to the change detection output. However, for part-building demolition or extension, a connected component analysis algorithm is applied, and for each connected building component, the area, width and height are estimated in order to ascertain if it can be considered as a demolished or new building-part. Using the developed GUI, a user can quickly examine each suggested change and indicate his/her decision to update the database, with a minimum number of mouse clicks. In experimental tests, the proposed change detection technique was found to produce almost no omission errors, and when compared to the number of reference building corners, it reduced the human interaction to 14% for initial building map generation and to 3% for map updating. Thus, the proposed approach can be exploited for enhanced automated building information updating within a topographic database.
Parallel Adaptive Mesh Refinement
Energy Technology Data Exchange (ETDEWEB)
Diachin, L; Hornung, R; Plassmann, P; WIssink, A
2005-03-04
As large-scale, parallel computers have become more widely available and numerical models and algorithms have advanced, the range of physical phenomena that can be simulated has expanded dramatically. Many important science and engineering problems exhibit solutions with localized behavior where highly-detailed salient features or large gradients appear in certain regions which are separated by much larger regions where the solution is smooth. Examples include chemically-reacting flows with radiative heat transfer, high Reynolds number flows interacting with solid objects, and combustion problems where the flame front is essentially a two-dimensional sheet occupying a small part of a three-dimensional domain. Modeling such problems numerically requires approximating the governing partial differential equations on a discrete domain, or grid. Grid spacing is an important factor in determining the accuracy and cost of a computation. A fine grid may be needed to resolve key local features while a much coarser grid may suffice elsewhere. Employing a fine grid everywhere may be inefficient at best and, at worst, may make an adequately resolved simulation impractical. Moreover, the location and resolution of fine grid required for an accurate solution is a dynamic property of a problem's transient features and may not be known a priori. Adaptive mesh refinement (AMR) is a technique that can be used with both structured and unstructured meshes to adjust local grid spacing dynamically to capture solution features with an appropriate degree of resolution. Thus, computational resources can be focused where and when they are needed most to efficiently achieve an accurate solution without incurring the cost of a globally-fine grid. Figure 1.1 shows two example computations using AMR; on the left is a structured mesh calculation of a impulsively-sheared contact surface and on the right is the fuselage and volume discretization of an RAH-66 Comanche helicopter [35]. Note the
Wang, Xinheng
2008-01-01
Wireless telemedicine using GSM and GPRS technologies can only provide low bandwidth connections, which makes it difficult to transmit images and video. Satellite or 3G wireless transmission provides greater bandwidth, but the running costs are high. Wireless networks (WLANs) appear promising, since they can supply high bandwidth at low cost. However, the WLAN technology has limitations, such as coverage. A new wireless networking technology named the wireless mesh network (WMN) overcomes some of the limitations of the WLAN. A WMN combines the characteristics of both a WLAN and ad hoc networks, thus forming an intelligent, large scale and broadband wireless network. These features are attractive for telemedicine and telecare because of the ability to provide data, voice and video communications over a large area. One successful wireless telemedicine project which uses wireless mesh technology is the Emergency Room Link (ER-LINK) in Tucson, Arizona, USA. There are three key characteristics of a WMN: self-organization, including self-management and self-healing; dynamic changes in network topology; and scalability. What we may now see is a shift from mobile communication and satellite systems for wireless telemedicine to the use of wireless networks based on mesh technology, since the latter are very attractive in terms of cost, reliability and speed. PMID:19047448
Directory of Open Access Journals (Sweden)
William Barragán Zaque
2015-06-01
Full Text Available The aim of this paper is to generate photogrammetrie products and to automatically map buildings in the area of interest in vector format. The research was conducted Bogotá using high resolution digital vertical aerial photographs and point clouds obtained using LIDAR technology. Image segmentation was also used, alongside radiometric and geometric digital processes. The process took into account aspects including building height, segmentation algorithms, and spectral band combination. The results had an effectiveness of 97.2 % validated through ground-truthing.
G. T. Kulakov; A. T. Kulakov; A. N. Kukharenko
2014-01-01
The paper analyzes an operation of the standard three-impulse automatic control system (ACS) for steam generator water supply. Mathematical model for checking its operational ability on load relief has been developed in the paper and this model makes it possible to determine maximum deviations of water level without execution of actual tests and any corrections in the plants for starting-up of technological protection systems in accordance with water level in the drum. The paper reveals rea...
Coupling of non-conforming meshes in a component mode synthesis method
Akcay-Perdahcioglu, D.; Doreille, M.; Boer, de A.; Ludwig, T.
2013-01-01
A common mesh refinement-based coupling technique is embedded into a component mode synthesis method, Craig–Bampton. More specifically, a common mesh is generated between the non-conforming interfaces of the coupled structures, and the compatibility constraints are enforced on that mesh via L2-minim
International Nuclear Information System (INIS)
The discrete ordinates (SN) method is widely used to obtain numerical solutions of the transport equation. The method calls for discretization of spatial, energy, and angular variables. To generate an 'effective' spatial mesh distribution, one has to consider various factors including particle mean free path (mfp), material and source discontinuities, and problem objectives. This becomes more complicated if we consider the effect of numerics such as differencing schemes, parallel processing strategies, and computation resources. As a result, one may often over/under-mesh depending upon limitations on accuracy, computing resources, and time allotted. To overcome the foregoing issues, we are developing an expert system for input preparation of the discrete ordinates (SN) method. This project is a part of an ongoing project sponsored by Nuclear Engineering Education Research. Our expert system consists of two parts: (a) an algorithm for generation of a mesh distribution for a serial calculation and (b) an algorithm for extension to parallel computing, which accounts for parallelization parameters including granularity, load balancing, parallel algorithms, and possible architectural issues. Thus far, we have developed a stand-alone algorithm for generation of an 'effective' mesh distribution for a serial calculation. The algorithm has been successfully tested with the Parallel Environment Neutral-Particle Transport (PENTRAN) code system. In this paper, we discuss the structure of our algorithm and present its use for simulating the VENUS-3 experimental facility. To date, we have developed and tested part 1 of this system. This part comprises of four steps: creation of a geometric model and coarse meshes, calculation of un-collided flux, selection of differencing schemes, and generation of fine-mesh distribution. For the un-collided flux calculation, we have developed a parallel code called PENFC. It is capable of calculating un-collided and first-collision fluxes for 3
Zollo, Aldo
2016-04-01
RISS S.r.l. is a Spin-off company recently born from the initiative of the research group constituting the Seismology Laboratory of the Department of Physics of the University of Naples Federico II. RISS is an innovative start-up, based on the decade-long experience in earthquake monitoring systems and seismic data analysis of its members and has the major goal to transform the most recent innovations of the scientific research into technological products and prototypes. With this aim, RISS has recently started the development of a new software, which is an elegant solution to manage and analyse seismic data and to create automatic earthquake bulletins. The software has been initially developed to manage data recorded at the ISNet network (Irpinia Seismic Network), which is a network of seismic stations deployed in Southern Apennines along the active fault system responsible for the 1980, November 23, MS 6.9 Irpinia earthquake. The software, however, is fully exportable and can be used to manage data from different networks, with any kind of station geometry or network configuration and is able to provide reliable estimates of earthquake source parameters, whichever is the background seismicity level of the area of interest. Here we present the real-time automated procedures and the analyses performed by the software package, which is essentially a chain of different modules, each of them aimed at the automatic computation of a specific source parameter. The P-wave arrival times are first detected on the real-time streaming of data and then the software performs the phase association and earthquake binding. As soon as an event is automatically detected by the binder, the earthquake location coordinates and the origin time are rapidly estimated, using a probabilistic, non-linear, exploration algorithm. Then, the software is able to automatically provide three different magnitude estimates. First, the local magnitude (Ml) is computed, using the peak-to-peak amplitude
Energy Technology Data Exchange (ETDEWEB)
Yang, D; Li, X; Li, H; Wooten, H; Green, O; Rodriguez, V; Mutic, S [Washington University School of Medicine, St. Louis, MO (United States)
2014-06-15
Purpose: Two aims of this work were to develop a method to automatically verify treatment delivery accuracy immediately after patient treatment and to develop a comprehensive daily treatment report to provide all required information for daily MR-IGRT review. Methods: After systematically analyzing the requirements for treatment delivery verification and understanding the available information from a novel MR-IGRT treatment machine, we designed a method to use 1) treatment plan files, 2) delivery log files, and 3) dosimetric calibration information to verify the accuracy and completeness of daily treatment deliveries. The method verifies the correctness of delivered treatment plans and beams, beam segments, and for each segment, the beam-on time and MLC leaf positions. Composite primary fluence maps are calculated from the MLC leaf positions and the beam-on time. Error statistics are calculated on the fluence difference maps between the plan and the delivery. We also designed the daily treatment delivery report by including all required information for MR-IGRT and physics weekly review - the plan and treatment fraction information, dose verification information, daily patient setup screen captures, and the treatment delivery verification results. Results: The parameters in the log files (e.g. MLC positions) were independently verified and deemed accurate and trustable. A computer program was developed to implement the automatic delivery verification and daily report generation. The program was tested and clinically commissioned with sufficient IMRT and 3D treatment delivery data. The final version has been integrated into a commercial MR-IGRT treatment delivery system. Conclusion: A method was developed to automatically verify MR-IGRT treatment deliveries and generate daily treatment reports. Already in clinical use since December 2013, the system is able to facilitate delivery error detection, and expedite physician daily IGRT review and physicist weekly chart
International Nuclear Information System (INIS)
In epidemiological studies as well as in clinical practice the amount of produced medical image data strongly increased in the last decade. In this context organ segmentation in MR volume data gained increasing attention for medical applications. Especially in large-scale population-based studies organ volumetry is highly relevant requiring exact organ segmentation. Since manual segmentation is time-consuming and prone to reader variability, large-scale studies need automatized methods to perform organ segmentation. Fully automatic organ segmentation in native MR image data has proven to be a very challenging task. Imaging artifacts as well as inter- and intrasubject MR-intensity differences complicate the application of supervised learning strategies. Thus, we propose a modularized framework of a two-stepped probabilistic approach that generates subject-specific probability maps for renal parenchyma tissue, which are refined subsequently by using several, extended segmentation strategies. We present a three class-based support vector machine recognition system that incorporates Fourier descriptors as shape features to recognize and segment characteristic parenchyma parts. Probabilistic methods use the segmented characteristic parenchyma parts to generate high quality subject-specific parenchyma probability maps. Several refinement strategies including a final shape-based 3D level set segmentation technique are used in subsequent processing modules to segment renal parenchyma. Furthermore, our framework recognizes and excludes renal cysts from parenchymal volume, which is important to analyze renal functions. Volume errors and Dice coefficients show that our presented framework outperforms existing approaches. (paper)
Gloger, Oliver; Tönnies, Klaus; Mensel, Birger; Völzke, Henry
2015-11-01
In epidemiological studies as well as in clinical practice the amount of produced medical image data strongly increased in the last decade. In this context organ segmentation in MR volume data gained increasing attention for medical applications. Especially in large-scale population-based studies organ volumetry is highly relevant requiring exact organ segmentation. Since manual segmentation is time-consuming and prone to reader variability, large-scale studies need automatized methods to perform organ segmentation. Fully automatic organ segmentation in native MR image data has proven to be a very challenging task. Imaging artifacts as well as inter- and intrasubject MR-intensity differences complicate the application of supervised learning strategies. Thus, we propose a modularized framework of a two-stepped probabilistic approach that generates subject-specific probability maps for renal parenchyma tissue, which are refined subsequently by using several, extended segmentation strategies. We present a three class-based support vector machine recognition system that incorporates Fourier descriptors as shape features to recognize and segment characteristic parenchyma parts. Probabilistic methods use the segmented characteristic parenchyma parts to generate high quality subject-specific parenchyma probability maps. Several refinement strategies including a final shape-based 3D level set segmentation technique are used in subsequent processing modules to segment renal parenchyma. Furthermore, our framework recognizes and excludes renal cysts from parenchymal volume, which is important to analyze renal functions. Volume errors and Dice coefficients show that our presented framework outperforms existing approaches.
Zollo, Aldo
2016-04-01
RISS S.r.l. is a Spin-off company recently born from the initiative of the research group constituting the Seismology Laboratory of the Department of Physics of the University of Naples Federico II. RISS is an innovative start-up, based on the decade-long experience in earthquake monitoring systems and seismic data analysis of its members and has the major goal to transform the most recent innovations of the scientific research into technological products and prototypes. With this aim, RISS has recently started the development of a new software, which is an elegant solution to manage and analyse seismic data and to create automatic earthquake bulletins. The software has been initially developed to manage data recorded at the ISNet network (Irpinia Seismic Network), which is a network of seismic stations deployed in Southern Apennines along the active fault system responsible for the 1980, November 23, MS 6.9 Irpinia earthquake. The software, however, is fully exportable and can be used to manage data from different networks, with any kind of station geometry or network configuration and is able to provide reliable estimates of earthquake source parameters, whichever is the background seismicity level of the area of interest. Here we present the real-time automated procedures and the analyses performed by the software package, which is essentially a chain of different modules, each of them aimed at the automatic computation of a specific source parameter. The P-wave arrival times are first detected on the real-time streaming of data and then the software performs the phase association and earthquake binding. As soon as an event is automatically detected by the binder, the earthquake location coordinates and the origin time are rapidly estimated, using a probabilistic, non-linear, exploration algorithm. Then, the software is able to automatically provide three different magnitude estimates. First, the local magnitude (Ml) is computed, using the peak-to-peak amplitude
Automatic Test Case Generator for Object-Z Specification%Object-Z规格说明测试用例的自动生成器
Institute of Scientific and Technical Information of China (English)
许庆国; 缪淮扣; 曹晓夏; 胡晓波
2011-01-01
Most research on test case generation from Object-Z specification focuses on theory. There is almost no tool to support generating test cases automatically. The Object-Z is a mathematics and logic based formal specification language. It uses schema composition and abbreviation format, which brings difficulty for extracting semantics and then generating test cases from specification automatically. This paper provides a solution in extracting semantics and generating test cases from Object-Z specification by unfolding the schema definition and improving its syntax in Object-Z. The process has three steps including parsing Object-Z language, extracting semantics, and generating test cases automatically.%对Object-Z形式规格说明构造测试用例的研究,目前主要集中在理论研究阶段,测试用例的自动生成几乎没有相应的工具支持.Object-Z是基于数学和逻辑的语言,并大量使用了模式复合和简写形式,这给计算机提取完整语义用以自动产生测试用例造成了困难.通过展开Object-Z规格说明中的模式定义,改进Object-Z的文法结构,给出了提取Object-Z规格说明语义的方法,研究了从Object-Z规格说明产生测试用例的自动化过程.这一过程主要包含3个阶段:Object-Z语言的自动解析、语义自动抽取和测试用例自动产生.通过介绍的工具原型,可以很容易得到规格说明中的各种语义;基于某些测试准则,能够方便自动产生可视化的抽象测试用例.
Hsu, Wei-Hung; Masim, Frances Camille P; Porta, Matteo; Nguyen, Mai Thanh; Yonezawa, Tetsu; Balčytis, Armandas; Wang, Xuewen; Rosa, Lorenzo; Juodkazis, Saulius; Hatanaka, Koji
2016-09-01
Femtosecond laser-induced hard X-ray generation in air from a 100-µm-thick solution film of distilled water or Au nano-sphere suspension was carried out by using a newly-developed automatic positioning system with 1-µm precision. By positioning the solution film for the highest X-ray intensity, the optimum position shifted upstream as the laser power increased due to breakdown. Optimized positioning allowed us to control X-ray intensity with high fidelity. X-ray generation from Au nano-sphere suspension and distilled water showed different power scaling. Linear and nonlinear absorption mechanism are analyzed together with numerical modeling of light delivery. PMID:27607607
International Nuclear Information System (INIS)
The article presents the models of Automatic Control System (ACS) and synchronous generator of the reversible generator-engine groups of first category power supply section in the Kozloduy NPP units 1 to 4. The control parameter is the synchronous machine tension. The research aims are optimal ACS setups, property control guaranties in accordance with the technical requirements. The used synchronous machine model is included in Matlab5.x library. For optimization the instruments of optimization toolbox - NCD out port block and plant actuator and created basic models of variable Discrete PID-regulator and PWM system are utilized. The results are applied for the setup of the real ACS. The results precision of the created models gives a possibility for a real summary model development and the achieved models implementation in cases of fluctuations of AC/DC reversible electromechanical supply
Directory of Open Access Journals (Sweden)
Daniel HOMOCIANU
2015-01-01
Full Text Available The paper introduces some considerations on a previously defined general purpose system used to dynamically generate online evaluation forms with automatic feedback immediately after submitting responses and working with a simple and well-known data source format able to store questions, answers and links to additional support materials in order to increase the productivity of evaluation and assessment. Beyond presenting a short description of the prototype’s components and underlining advantages and limitations of using it for any user involved in assessment and evaluation processes, this paper promotes the use of such a system together with a simple technique of generating and referencing interactive support content cited within this paper and defined together with the LIVES4IT approach. This type of content means scenarios having adhoc documentation and interactive simulation components useful when emulating concrete examples of working with real world objects, operating with devices or using software applications from any activity field.
Verification of radiation transport codes with unstructured meshes
International Nuclear Information System (INIS)
Confidence in the results of a radiation transport code requires that the code be verified against problems with known solutions. Such verification problems may be generated by means of the method of manufactured solutions. Previously we reported the application of this method to the verification of radiation transport codes for structured meshes, in particular the SCEPTRE code. We extend this work to verification with unstructured meshes and again apply it to SCEPTRE. We report on additional complexities for unstructured mesh verification of transport codes. Refinement of such meshes for error convergence studies is more involved, particularly for tetrahedral meshes. Furthermore, finite element integrations arising from the presence of the streaming operator exhibit different behavior for unstructured meshes than for structured meshes. We verify SCEPTRE with a combination of 'exact' and 'inexact' problems. Errors in the results are consistent with the discretizations, either being limited to roundoff error or displaying the expected rates of convergence with mesh refinement. We also observe behaviors in the results that were difficult to analyze and predict from a strictly theoretical basis, thereby yielding benefits from verification activities beyond demonstrating code correctness. (author)
VPN Mesh in Industrial Networking
Berndtsson, Andreas
2013-01-01
This thesis report describes the process and present the results gained while evaluating available VPN mesh solutions and equipment for integration into Industrial systems. The task was divided into several sub steps; summarize the previous work done in the VPN mesh area, evaluate the available VPN mesh solutions, verify that the interesting equipment comply with the criteria set by ABB and lastly verify that the equipment can be integrated transparently into already running systems. The resu...
Synthesized Optimization of Triangular Mesh
Institute of Scientific and Technical Information of China (English)
HU Wenqiang; YANG Wenyu
2006-01-01
Triangular mesh is often used to describe geometric object as computed model in digital manufacture, thus the mesh model with both uniform triangular shape and excellent geometric shape is expected. But in fact, the optimization of triangular shape often is contrary with that of geometric shape. In this paper, one synthesized optimizing algorithm is presented through subdividing triangles to achieve the trade-off solution between the geometric and triangular shape optimization of mesh model. The result mesh with uniform triangular shape and excellent topology are obtained.
Ye, Dexin; Lu, Ling; Joannopoulos, John D; Soljačić, Marin; Ran, Lixin
2016-03-01
A solid material possessing identical electromagnetic properties as air has yet to be found in nature. Such a medium of arbitrary shape would neither reflect nor refract light at any angle of incidence in free space. Here, we introduce nonscattering corrugated metallic wires to construct such a medium. This was accomplished by aligning the dark-state frequencies in multiple scattering channels of a single wire. Analytical solutions, full-wave simulations, and microwave measurement results on 3D printed samples show omnidirectional invisibility in any configuration. This invisible metallic mesh can improve mechanical stability, electrical conduction, and heat dissipation of a system, without disturbing the electromagnetic design. Our approach is simple, robust, and scalable to higher frequencies. PMID:26884208
Taĭts, B M
1993-01-01
To treat acute stenosing laryngotracheitis in acute respiratory viral infection in children an original method has been developed and used for 2 years in a special hospital department. The method implies treatment of children in steam-and-oxygen tents with a universal steam-moistening generator and automatic control system. A controlled study of 50 children with acute laryngeal stenosis degree I-III confirmed high efficacy of this method permitting improvement of blood oxygenation, gas composition, acid-base condition, reduction of acidosis, prevention of exicosis and brain edema. Warm humid atmosphere promoted better discharge of the secretion and better functioning of the ciliated epithelium. Combined treatment incorporating the tents in acute laryngeal stenoses reduced lethality in severe cases, number of intubations and tracheostomies, of complications resultant from parenteral administration of the drugs. PMID:8009767
International Nuclear Information System (INIS)
Purpose: To evaluate the implications of differences between contours drawn manually and contours generated automatically by deformable image registration for four-dimensional (4D) treatment planning. Methods and Materials: In 12 lung cancer patients intensity-modulated radiotherapy (IMRT) planning was performed for both manual contours and automatically generated ('auto') contours in mid and peak expiration of 4D computed tomography scans, with the manual contours in peak inspiration serving as the reference for the displacement vector fields. Manual and auto plans were analyzed with respect to their coverage of the manual contours, which were assumed to represent the anatomically correct volumes. Results: Auto contours were on average larger than manual contours by up to 9%. Objective scores, D2% and D98% of the planning target volume, homogeneity and conformity indices, and coverage of normal tissue structures (lungs, heart, esophagus, spinal cord) at defined dose levels were not significantly different between plans (p = 0.22-0.94). Differences were statistically insignificant for the generalized equivalent uniform dose of the planning target volume (p = 0.19-0.94) and normal tissue complication probabilities for lung and esophagus (p = 0.13-0.47). Dosimetric differences >2% or >1 Gy were more frequent in patients with auto/manual volume differences ≥10% (p = 0.04). Conclusions: The applied deformable image registration algorithm produces clinically plausible auto contours in the majority of structures. At this stage clinical supervision of the auto contouring process is required, and manual interventions may become necessary. Before routine use, further investigations are required, particularly to reduce imaging artifacts
Towards a real time computation of the dose in a phantom segmented into homogeneous meshes
International Nuclear Information System (INIS)
Automatic radiation therapy treatment planning necessitates a very fast computation of the dose delivered to the patient. We propose to compute the dose by segmenting the patient's phantom into homogeneous meshes, and by associating, to the meshes, projections to dose distributions pre-computed in homogeneous phantoms, along with weights managing heterogeneities. The dose computation is divided into two steps. The first step impacts the meshes: projections and weights are set according to physical and geometrical criteria. The second step impacts the voxels: the dose is computed by evaluating the functions previously associated to their mesh. This method is very fast, in particular when there are few points of interest (several hundreds). In this case, results are obtained in less than one second. With such performances, practical realization of automatic treatment planning becomes practically feasible. (author)
DEFF Research Database (Denmark)
Burelli, Paolo; Preuss, Mike
2014-01-01
Automatically generating computer animations is a challenging and complex problem with applications in games and film production. In this paper, we investigate howto translate a shot list for a virtual scene into a series of virtual camera configurations — i.e automatically controlling the virtual...... camera. We approach this problem by modelling it as a dynamic multi-objective optimisation problem and show how this metaphor allows a much richer expressiveness than a classical single objective approach. Finally, we showcase the application of a multi-objective evolutionary algorithm to generate a shot...
Directory of Open Access Journals (Sweden)
K. Foit
2011-07-01
Full Text Available Purpose: of this paper: This paper discuss the possibility to develop and implementing the computer system, which could be able to generate a collision-free path and prepare the data for direct implementing in the robot’s program.Design/methodology/approach: The existing methods of planning of the collision-free paths are mainly limited to the 2D issue and implemented for the mobile robots. The existing methods for planning the trajectory in 3D are often complicated and time-consuming, so most of them are not introduced in reality, being only a theory. In the paper the 2½D method has been presented together with the method of smoothing the generated trajectory. Experiments have been carried out in the virtual environment as well as on the real robot.Findings: The developed PLANER application has been adapted for cooperation with the Mitsubishi Movemaster RV-M1 robot. The current tests, together with the previous one carried out on the Fanuc RJ3iB robot, have shown the versatility of the method and the possibility to adapt it for cooperation with any robotic system.Research limitations/implications: The further stage of research will be concentrated on the consolidation of trajectory generating and simulation phase with the program execution stage in such a way, that the determination of collision-free path could be realized in real time.Practical implications: This approach clearly simplifies the stage of defining the relevant points of the trajectory in order to avoid collisions with the technological objects located in the robot’s manipulator environment. Thereby it significantly reduces the time needed for implementation of the program to the production cycle.Originality/value: The method of generating the collision-free trajectories, which is described in the paper, combines some of the existing tools with the new approach to achieve the optimal performance of the algorithm.
Saurabh Pal; Sudipta Bhattacharya; Indrani Datta; Arindam Chakravorty
2012-01-01
Question Answering System [QAS] generates answer to various questions imposed by users. The QAS uses documents or knowledge base for extracting the answers to factoid questions and conceptual questions. Use of Frequently Asked Question (FAQ) base gives a satisfying results to QAS, but the limitation with FAQ base system is in the preparation of Question and Answer set as most of the questions are not predetermined.QAS using FAQ base fails if no semantically related questions are found in base...
A zoomable and adaptable hidden fine-mesh approach to solving advection-dispersion equations
International Nuclear Information System (INIS)
A zoomable and adaptable hidden fine-mesh approach (ZAHFMA), that can be used with either finite element or finite difference methods, is proposed to solve the advection-dispersion equation. The approach is based on automatic adaptation of zooming a hidden fine-mesh in the place where the sharp front locates. Preliminary results indicate that ZAHFMA used with finite element methods can handle the advection-dispersion problems with Peclet number ranging from 0 to ∞. 5 refs., 2 figs
Energy Technology Data Exchange (ETDEWEB)
Greene, Patrick T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schofield, Samuel P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nourgaliev, Robert [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2016-06-21
A new mesh smoothing method designed to cluster mesh cells near a dynamically evolving interface is presented. The method is based on weighted condition number mesh relaxation with the weight function being computed from a level set representation of the interface. The weight function is expressed as a Taylor series based discontinuous Galerkin projection, which makes the computation of the derivatives of the weight function needed during the condition number optimization process a trivial matter. For cases when a level set is not available, a fast method for generating a low-order level set from discrete cell-centered elds, such as a volume fraction or index function, is provided. Results show that the low-order level set works equally well for the weight function as the actual level set. Meshes generated for a number of interface geometries are presented, including cases with multiple level sets. Dynamic cases for moving interfaces are presented to demonstrate the method's potential usefulness to arbitrary Lagrangian Eulerian (ALE) methods.
Finite element simulation of impact response of wire mesh screens
Directory of Open Access Journals (Sweden)
Wang Caizheng
2015-01-01
Full Text Available In this paper, the response of wire mesh screens to low velocity impact with blunt objects is investigated using finite element (FE simulation. The woven wire mesh is modelled with homogeneous shell elements with equivalent smeared mechanical properties. The mechanical behaviour of the woven wire mesh was determined experimentally with tensile tests on steel wire mesh coupons to generate the data for the smeared shell material used in the FE. The effects of impacts with a low mass (4 kg and a large mass (40 kg providing the same impact energy are studied. The joint between the wire mesh screen and the aluminium frame surrounding it is modelled using contact elements with friction between the corresponding elements. Damage to the screen of different types compromising its structural integrity, such as mesh separation and pulling out from the surrounding frame is modelled. The FE simulation is validated with results of impact tests conducted on woven steel wire screen meshes.
Gamra: Simple meshing for complex earthquakes
Landry, Walter; Barbot, Sylvain
2016-05-01
The static offsets caused by earthquakes are well described by elastostatic models with a discontinuity in the displacement along the fault. A traditional approach to model this discontinuity is to align the numerical mesh with the fault and solve the equations using finite elements. However, this distorted mesh can be difficult to generate and update. We present a new numerical method, inspired by the Immersed Interface Method (Leveque and Li, 1994), for solving the elastostatic equations with embedded discontinuities. This method has been carefully designed so that it can be used on parallel machines on an adapted finite difference grid. We have implemented this method in Gamra, a new code for earth modeling. We demonstrate the correctness of the method with analytic tests, and we demonstrate its practical performance by solving a realistic earthquake model to extremely high precision.
Gamra: Simple Meshes for Complex Earthquakes
Landry, Walter
2016-01-01
The static offsets caused by earthquakes are well described by elastostatic models with a discontinuity in the displacement along the fault. A traditional approach to model this discontinuity is to align the numerical mesh with the fault and solve the equations using finite elements. However, this distorted mesh can be difficult to generate and update. We present a new numerical method, inspired by the Immersed Interface Method, for solving the elastostatic equations with embedded discontinuities. This method has been carefully designed so that it can be used on parallel machines on an adapted finite difference grid. We have implemented this method in Gamra, a new code for earth modelling. We demonstrate the correctness of the method with analytic tests, and we demonstrate its practical performance by solving a realistic earthquake model to extremely high precision.
Motion Editing for Time-Varying Mesh
Xu, Jianfeng; Yamasaki, Toshihiko; Aizawa, Kiyoharu
2008-12-01
Recently, time-varying mesh (TVM), which is composed of a sequence of mesh models, has received considerable interest due to its new and attractive functions such as free viewpoint and interactivity. TVM captures the dynamic scene of the real world from multiple synchronized cameras. However, it is expensive and time consuming to generate a TVM sequence. In this paper, an editing system is presented to reuse the original data, which reorganizes the motions to obtain a new sequence based on the user requirements. Hierarchical motion structure is observed and parsed in TVM sequences. Then, the representative motions are chosen into a motion database, where a motion graph is constructed to connect those motions with smooth transitions. After the user selects some desired motions from the motion database, the best paths are searched by a modified Dijkstra algorithm to achieve a new sequence. Our experimental results demonstrate that the edited sequences are natural and smooth.