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Sample records for rendering spectral elements

  1. Spectral/hp element methods for CFD

    CERN Document Server

    Karniadakis, George Em

    1999-01-01

    Traditionally spectral methods in fluid dynamics were used in direct and large eddy simulations of turbulent flow in simply connected computational domains. The methods are now being applied to more complex geometries, and the spectral/hp element method, which incorporates both multi-domain spectral methods and high-order finite element methods, has been particularly successful. This book provides a comprehensive introduction to these methods. Written by leaders in the field, the book begins with a full explanation of fundamental concepts and implementation issues. It then illustrates how these methods can be applied to advection-diffusion and to incompressible and compressible Navier-Stokes equations. Drawing on both published and unpublished material, the book is an important resource for experienced researchers and for those new to the field.

  2. Introduction to finite and spectral element methods using Matlab

    CERN Document Server

    Pozrikidis, Constantine

    2014-01-01

    The Finite Element Method in One Dimension. Further Applications in One Dimension. High-Order and Spectral Elements in One Dimension. The Finite Element Method in Two Dimensions. Quadratic and Spectral Elements in Two Dimensions. Applications in Mechanics. Viscous Flow. Finite and Spectral Element Methods in Three Dimensions. Appendices. References. Index.

  3. Stability estimates for hp spectral element methods for general ...

    Indian Academy of Sciences (India)

    We establish basic stability estimates for a non-conforming ℎ- spectral element method which allows for simultaneous mesh refinement and variable polynomial degree. The spectral element functions are non-conforming if the boundary conditions are Dirichlet. For problems with mixed boundary conditions they are ...

  4. Spectral element method for wave propagation on irregular domains

    Indian Academy of Sciences (India)

    Yan Hui Geng

    2018-03-14

    Mar 14, 2018 ... Abstract. A spectral element approximation of acoustic propagation problems combined with a new mapping method on irregular domains is proposed. Following this method, the Gauss–Lobatto–Chebyshev nodes in the standard space are applied to the spectral element method (SEM). The nodes in the ...

  5. Spectral element method for wave propagation on irregular domains

    Indian Academy of Sciences (India)

    A spectral element approximation of acoustic propagation problems combined with a new mapping method on irregular domains is proposed. Following this method, the Gauss–Lobatto–Chebyshev nodes in the standard space are applied to the spectral element method (SEM). The nodes in the physical space are ...

  6. hp Spectral element methods for three dimensional elliptic problems

    Indian Academy of Sciences (India)

    This is the first of a series of papers devoted to the study of h-p spec- .... element functions defined on mesh elements in the new system of variables with a uni- ... the spectral element functions on these elements and give construction of the stability .... By Hm( ), we denote the usual Sobolev space of integer order m ≥ 0 ...

  7. Convergence analysis of spectral element method for electromechanical devices

    NARCIS (Netherlands)

    Curti, M.; Jansen, J.W.; Lomonova, E.A.

    2017-01-01

    This paper concerns the comparison of the performance of the Spectral Element Method (SEM) and the Finite Element Method (FEM) for a magnetostatic problem. The convergence of the vector magnetic potential, the magnetic flux density, and the total stored energy in the system is compared with the

  8. Convergence analysis of spectral element method for magnetic devices

    NARCIS (Netherlands)

    Curti, M.; Jansen, J.W.; Lomonova, E.A.

    2018-01-01

    This paper concerns the comparison of the performance of the Spectral Element Method (SEM) and the Finite Element Method (FEM) for modeling a magnetostatic problem. The convergence of the vector magnetic potential, the magnetic flux density, and the total stored energy in the system is compared with

  9. Spectral/ hp element methods: Recent developments, applications, and perspectives

    Science.gov (United States)

    Xu, Hui; Cantwell, Chris D.; Monteserin, Carlos; Eskilsson, Claes; Engsig-Karup, Allan P.; Sherwin, Spencer J.

    2018-02-01

    The spectral/ hp element method combines the geometric flexibility of the classical h-type finite element technique with the desirable numerical properties of spectral methods, employing high-degree piecewise polynomial basis functions on coarse finite element-type meshes. The spatial approximation is based upon orthogonal polynomials, such as Legendre or Chebychev polynomials, modified to accommodate a C 0 - continuous expansion. Computationally and theoretically, by increasing the polynomial order p, high-precision solutions and fast convergence can be obtained and, in particular, under certain regularity assumptions an exponential reduction in approximation error between numerical and exact solutions can be achieved. This method has now been applied in many simulation studies of both fundamental and practical engineering flows. This paper briefly describes the formulation of the spectral/ hp element method and provides an overview of its application to computational fluid dynamics. In particular, it focuses on the use of the spectral/ hp element method in transitional flows and ocean engineering. Finally, some of the major challenges to be overcome in order to use the spectral/ hp element method in more complex science and engineering applications are discussed.

  10. Numerical and spectral investigations of novel infinite elements

    International Nuclear Information System (INIS)

    Barai, P.; Harari, I.; Barbonet, P.E.

    1998-01-01

    Exterior problems of time-harmonic acoustics are addressed by a novel infinite element formulation, defined on a bounded computational domain. For two-dimensional configurations with circular interfaces, the infinite element results match Quell both analytical values and those obtained from. other methods like DtN. Along 1uith the numerical performance of this formulation, of considerable interest are its complex-valued eigenvalues. Hence, a spectral analysis of the present scheme is also performed here, using various infinite elements

  11. Nonconforming h-p spectral element methods for elliptic problems

    Indian Academy of Sciences (India)

    In [6,7,13,14] h-p spectral element methods for solving elliptic boundary value problems on polygonal ... Let M denote the number of corner layers and W denote the number of degrees of .... β is given by Theorem 2.2 of [3] which can be stated.

  12. hp Spectral element methods for three dimensional elliptic problems

    Indian Academy of Sciences (India)

    elliptic boundary value problems on non-smooth domains in R3. For Dirichlet problems, ... of variable degree bounded by W. Let N denote the number of layers in the geomet- ric mesh ... We prove a stability theorem for mixed problems when the spectral element functions vanish ..... Applying Theorem 3.1,. ∫ r l. |Mu|2dx −.

  13. Unstructured Spectral Element Model for Dispersive and Nonlinear Wave Propagation

    DEFF Research Database (Denmark)

    Engsig-Karup, Allan Peter; Eskilsson, Claes; Bigoni, Daniele

    2016-01-01

    We introduce a new stabilized high-order and unstructured numerical model for modeling fully nonlinear and dispersive water waves. The model is based on a nodal spectral element method of arbitrary order in space and a -transformed formulation due to Cai, Langtangen, Nielsen and Tveito (1998). In...

  14. Element-by-element parallel spectral-element methods for 3-D teleseismic wave modeling

    KAUST Repository

    Liu, Shaolin

    2017-09-28

    The development of an efficient algorithm for teleseismic wave field modeling is valuable for calculating the gradients of the misfit function (termed misfit gradients) or Fréchet derivatives when the teleseismic waveform is used for adjoint tomography. Here, we introduce an element-by-element parallel spectral-element method (EBE-SEM) for the efficient modeling of teleseismic wave field propagation in a reduced geology model. Under the plane-wave assumption, the frequency-wavenumber (FK) technique is implemented to compute the boundary wave field used to construct the boundary condition of the teleseismic wave incidence. To reduce the memory required for the storage of the boundary wave field for the incidence boundary condition, a strategy is introduced to efficiently store the boundary wave field on the model boundary. The perfectly matched layers absorbing boundary condition (PML ABC) is formulated using the EBE-SEM to absorb the scattered wave field from the model interior. The misfit gradient can easily be constructed in each time step during the calculation of the adjoint wave field. Three synthetic examples demonstrate the validity of the EBE-SEM for use in teleseismic wave field modeling and the misfit gradient calculation.

  15. Symplectic discretization for spectral element solution of Maxwell's equations

    International Nuclear Information System (INIS)

    Zhao Yanmin; Dai Guidong; Tang Yifa; Liu Qinghuo

    2009-01-01

    Applying the spectral element method (SEM) based on the Gauss-Lobatto-Legendre (GLL) polynomial to discretize Maxwell's equations, we obtain a Poisson system or a Poisson system with at most a perturbation. For the system, we prove that any symplectic partitioned Runge-Kutta (PRK) method preserves the Poisson structure and its implied symplectic structure. Numerical examples show the high accuracy of SEM and the benefit of conserving energy due to the use of symplectic methods.

  16. Parallel rendering

    Science.gov (United States)

    Crockett, Thomas W.

    1995-01-01

    This article provides a broad introduction to the subject of parallel rendering, encompassing both hardware and software systems. The focus is on the underlying concepts and the issues which arise in the design of parallel rendering algorithms and systems. We examine the different types of parallelism and how they can be applied in rendering applications. Concepts from parallel computing, such as data decomposition, task granularity, scalability, and load balancing, are considered in relation to the rendering problem. We also explore concepts from computer graphics, such as coherence and projection, which have a significant impact on the structure of parallel rendering algorithms. Our survey covers a number of practical considerations as well, including the choice of architectural platform, communication and memory requirements, and the problem of image assembly and display. We illustrate the discussion with numerous examples from the parallel rendering literature, representing most of the principal rendering methods currently used in computer graphics.

  17. PIXE-quantified AXSIA: Elemental mapping by multivariate spectral analysis

    International Nuclear Information System (INIS)

    Doyle, B.L.; Provencio, P.P.; Kotula, P.G.; Antolak, A.J.; Ryan, C.G.; Campbell, J.L.; Barrett, K.

    2006-01-01

    Automated, nonbiased, multivariate statistical analysis techniques are useful for converting very large amounts of data into a smaller, more manageable number of chemical components (spectra and images) that are needed to describe the measurement. We report the first use of the multivariate spectral analysis program AXSIA (Automated eXpert Spectral Image Analysis) developed at Sandia National Laboratories to quantitatively analyze micro-PIXE data maps. AXSIA implements a multivariate curve resolution technique that reduces the spectral image data sets into a limited number of physically realizable and easily interpretable components (including both spectra and images). We show that the principal component spectra can be further analyzed using conventional PIXE programs to convert the weighting images into quantitative concentration maps. A common elemental data set has been analyzed using three different PIXE analysis codes and the results compared to the cases when each of these codes is used to separately analyze the associated AXSIA principal component spectral data. We find that these comparisons are in good quantitative agreement with each other

  18. Bessel smoothing filter for spectral-element mesh

    Science.gov (United States)

    Trinh, P. T.; Brossier, R.; Métivier, L.; Virieux, J.; Wellington, P.

    2017-06-01

    Smoothing filters are extremely important tools in seismic imaging and inversion, such as for traveltime tomography, migration and waveform inversion. For efficiency, and as they can be used a number of times during inversion, it is important that these filters can easily incorporate prior information on the geological structure of the investigated medium, through variable coherent lengths and orientation. In this study, we promote the use of the Bessel filter to achieve these purposes. Instead of considering the direct application of the filter, we demonstrate that we can rely on the equation associated with its inverse filter, which amounts to the solution of an elliptic partial differential equation. This enhances the efficiency of the filter application, and also its flexibility. We apply this strategy within a spectral-element-based elastic full waveform inversion framework. Taking advantage of this formulation, we apply the Bessel filter by solving the associated partial differential equation directly on the spectral-element mesh through the standard weak formulation. This avoids cumbersome projection operators between the spectral-element mesh and a regular Cartesian grid, or expensive explicit windowed convolution on the finite-element mesh, which is often used for applying smoothing operators. The associated linear system is solved efficiently through a parallel conjugate gradient algorithm, in which the matrix vector product is factorized and highly optimized with vectorized computation. Significant scaling behaviour is obtained when comparing this strategy with the explicit convolution method. The theoretical numerical complexity of this approach increases linearly with the coherent length, whereas a sublinear relationship is observed practically. Numerical illustrations are provided here for schematic examples, and for a more realistic elastic full waveform inversion gradient smoothing on the SEAM II benchmark model. These examples illustrate well the

  19. Spectral element method for vector radiative transfer equation

    International Nuclear Information System (INIS)

    Zhao, J.M.; Liu, L.H.; Hsu, P.-F.; Tan, J.Y.

    2010-01-01

    A spectral element method (SEM) is developed to solve polarized radiative transfer in multidimensional participating medium. The angular discretization is based on the discrete-ordinates approach, and the spatial discretization is conducted by spectral element approach. Chebyshev polynomial is used to build basis function on each element. Four various test problems are taken as examples to verify the performance of the SEM. The effectiveness of the SEM is demonstrated. The h and the p convergence characteristics of the SEM are studied. The convergence rate of p-refinement follows the exponential decay trend and is superior to that of h-refinement. The accuracy and efficiency of the higher order approximation in the SEM is well demonstrated for the solution of the VRTE. The predicted angular distribution of brightness temperature and Stokes vector by the SEM agree very well with the benchmark solutions in references. Numerical results show that the SEM is accurate, flexible and effective to solve multidimensional polarized radiative transfer problems.

  20. Stabilization of numerical interchange in spectral-element magnetohydrodynamics

    Science.gov (United States)

    Sovinec, C. R.

    2016-08-01

    Auxiliary numerical projections of the divergence of flow velocity and vorticity parallel to magnetic field are developed and tested for the purpose of suppressing unphysical interchange instability in magnetohydrodynamic simulations. The numerical instability arises with equal-order C0 finite- and spectral-element expansions of the flow velocity, magnetic field, and pressure and is sensitive to behavior at the limit of resolution. The auxiliary projections are motivated by physical field-line bending, and coercive responses to the projections are added to the flow-velocity equation. Their incomplete expansions are limited to the highest-order orthogonal polynomial in at least one coordinate of the spectral elements. Cylindrical eigenmode computations show that the projections induce convergence from the stable side with first-order ideal-MHD equations during h-refinement and p-refinement. Hyperbolic and parabolic projections and responses are compared, together with different methods for avoiding magnetic divergence error. The projections are also shown to be effective in linear and nonlinear time-dependent computations with the NIMROD code Sovinec et al. [17], provided that the projections introduce numerical dissipation.

  1. Spectral Element Method for the Simulation of Unsteady Compressible Flows

    Science.gov (United States)

    Diosady, Laslo Tibor; Murman, Scott M.

    2013-01-01

    This work uses a discontinuous-Galerkin spectral-element method (DGSEM) to solve the compressible Navier-Stokes equations [1{3]. The inviscid ux is computed using the approximate Riemann solver of Roe [4]. The viscous fluxes are computed using the second form of Bassi and Rebay (BR2) [5] in a manner consistent with the spectral-element approximation. The method of lines with the classical 4th-order explicit Runge-Kutta scheme is used for time integration. Results for polynomial orders up to p = 15 (16th order) are presented. The code is parallelized using the Message Passing Interface (MPI). The computations presented in this work are performed using the Sandy Bridge nodes of the NASA Pleiades supercomputer at NASA Ames Research Center. Each Sandy Bridge node consists of 2 eight-core Intel Xeon E5-2670 processors with a clock speed of 2.6Ghz and 2GB per core memory. On a Sandy Bridge node the Tau Benchmark [6] runs in a time of 7.6s.

  2. Spectral response of multi-element silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ludewigt, B.A.; Rossington, C.S.; Chapman, K. [Univ. of California, Berkeley, CA (United States)

    1997-04-01

    Multi-element silicon strip detectors, in conjunction with integrated circuit pulse-processing electronics, offer an attractive alternative to conventional lithium-drifted silicon Si(Li) and high purity germanium detectors (HPGe) for high count rate, low noise synchrotron x-ray fluorescence applications. One of the major differences between the segmented Si detectors and the commercially available single-element Si(Li) or HPGe detectors is that hundreds of elements can be fabricated on a single Si substrate using standard silicon processing technologies. The segmentation of the detector substrate into many small elements results in very low noise performance at or near, room temperature, and the count rate of the detector is increased many-fold due to the multiplication in the total number of detectors. Traditionally, a single channel of detector with electronics can handle {approximately}100 kHz count rates while maintaining good energy resolution; the segmented detectors can operate at greater than MHz count rates merely due to the multiplication in the number of channels. One of the most critical aspects in the development of the segmented detectors is characterizing the charge sharing and charge loss that occur between the individual detector strips, and determining how these affect the spectral response of the detectors.

  3. Choice-Making in Rendering Culture-Bound Elements in Literary Translation: A Case Study on the English Translation Of «????»

    Science.gov (United States)

    Meihua, Song

    2014-01-01

    How to render culture-bound elements into a foreign language remains one of the most challenging tasks for all translators, especially, when the source text is a literary one. To retain the aesthetic effects and other stylistic features of importance, some argue that choice can be made from either domestication or foreignization with…

  4. Discrete conservation properties for shallow water flows using mixed mimetic spectral elements

    NARCIS (Netherlands)

    Lee, D.; Palha, A.; Gerritsma, M.

    2018-01-01

    A mixed mimetic spectral element method is applied to solve the rotating shallow water equations. The mixed method uses the recently developed spectral element histopolation functions, which exactly satisfy the fundamental theorem of calculus with respect to the standard Lagrange basis functions in

  5. Efficiency of High Order Spectral Element Methods on Petascale Architectures

    KAUST Repository

    Hutchinson, Maxwell; Heinecke, Alexander; Pabst, Hans; Henry, Greg; Parsani, Matteo; Keyes, David E.

    2016-01-01

    High order methods for the solution of PDEs expose a tradeoff between computational cost and accuracy on a per degree of freedom basis. In many cases, the cost increases due to higher arithmetic intensity while affecting data movement minimally. As architectures tend towards wider vector instructions and expect higher arithmetic intensities, the best order for a particular simulation may change. This study highlights preferred orders by identifying the high order efficiency frontier of the spectral element method implemented in Nek5000 and NekBox: the set of orders and meshes that minimize computational cost at fixed accuracy. First, we extract Nek’s order-dependent computational kernels and demonstrate exceptional hardware utilization by hardware-aware implementations. Then, we perform productionscale calculations of the nonlinear single mode Rayleigh-Taylor instability on BlueGene/Q and Cray XC40-based supercomputers to highlight the influence of the architecture. Accuracy is defined with respect to physical observables, and computational costs are measured by the corehour charge of the entire application. The total number of grid points needed to achieve a given accuracy is reduced by increasing the polynomial order. On the XC40 and BlueGene/Q, polynomial orders as high as 31 and 15 come at no marginal cost per timestep, respectively. Taken together, these observations lead to a strong preference for high order discretizations that use fewer degrees of freedom. From a performance point of view, we demonstrate up to 60% full application bandwidth utilization at scale and achieve ≈1PFlop/s of compute performance in Nek’s most flop-intense methods.

  6. Efficiency of High Order Spectral Element Methods on Petascale Architectures

    KAUST Repository

    Hutchinson, Maxwell

    2016-06-14

    High order methods for the solution of PDEs expose a tradeoff between computational cost and accuracy on a per degree of freedom basis. In many cases, the cost increases due to higher arithmetic intensity while affecting data movement minimally. As architectures tend towards wider vector instructions and expect higher arithmetic intensities, the best order for a particular simulation may change. This study highlights preferred orders by identifying the high order efficiency frontier of the spectral element method implemented in Nek5000 and NekBox: the set of orders and meshes that minimize computational cost at fixed accuracy. First, we extract Nek’s order-dependent computational kernels and demonstrate exceptional hardware utilization by hardware-aware implementations. Then, we perform productionscale calculations of the nonlinear single mode Rayleigh-Taylor instability on BlueGene/Q and Cray XC40-based supercomputers to highlight the influence of the architecture. Accuracy is defined with respect to physical observables, and computational costs are measured by the corehour charge of the entire application. The total number of grid points needed to achieve a given accuracy is reduced by increasing the polynomial order. On the XC40 and BlueGene/Q, polynomial orders as high as 31 and 15 come at no marginal cost per timestep, respectively. Taken together, these observations lead to a strong preference for high order discretizations that use fewer degrees of freedom. From a performance point of view, we demonstrate up to 60% full application bandwidth utilization at scale and achieve ≈1PFlop/s of compute performance in Nek’s most flop-intense methods.

  7. A mass and energy conserving spectral element atmospheric dynamical core on the cubed-sphere grid

    International Nuclear Information System (INIS)

    Taylor, M A; Edwards, J; Thomas, S; Nair, R

    2007-01-01

    We present results from a conservative formulation of the spectral element method applied to global atmospheric circulation modeling. Exact local conservation of both mass and energy is obtained via a new compatible formulation of the spectral element method. Compatibility insures that the key integral property of the divergence and gradient operators required to show conservation also hold in discrete form. The spectral element method is used on a cubed-sphere grid to discretize the horizontal directions on the sphere. It can be coupled to any conservative vertical/radial discretization. The accuracy and conservation properties of the method are illustrated using a baroclinic instability test case

  8. $h - p$ Spectral element methods for elliptic problems on non-smooth domains using parallel computers

    NARCIS (Netherlands)

    Tomar, S.K.

    2002-01-01

    It is well known that elliptic problems when posed on non-smooth domains, develop singularities. We examine such problems within the framework of spectral element methods and resolve the singularities with exponential accuracy.

  9. Wave propagation numerical models in damage detection based on the time domain spectral element method

    International Nuclear Information System (INIS)

    Ostachowicz, W; Kudela, P

    2010-01-01

    A Spectral Element Method is used for wave propagation modelling. A 3D solid spectral element is derived with shape functions based on Lagrange interpolation and Gauss-Lobatto-Legendre points. This approach is applied for displacement approximation suited for fundamental modes of Lamb waves as well as potential distribution in piezoelectric transducers. The novelty is the model geometry extension from flat to curved elements for application in shell-like structures. Exemplary visualisations of waves excited by the piezoelectric transducers in curved shell structure made of aluminium alloy are presented. Simple signal analysis of wave interaction with crack is performed. The crack is modelled by separation of appropriate nodes between elements. An investigation of influence of the crack length on wave propagation signals is performed. Additionally, some aspects of the spectral element method implementation are discussed.

  10. Spectral/hp element methods: Recent developments, applications, and perspectives

    DEFF Research Database (Denmark)

    Xu, Hui; Cantwell, Chris; Monteserin, Carlos

    2018-01-01

    regularity assumptions an exponential reduction in approximation error between numerical and exact solutions can be achieved. This method has now been applied in many simulation studies of both fundamental and practical engineering flows. This paper briefly describes the formulation of the spectral...... is based upon orthogonal polynomials, such as Legendre or Chebychev polynomials, modified to accommodate a C 0 - continuous expansion. Computationally and theoretically, by increasing the polynomial order p, high-precision solutions and fast convergence can be obtained and, in particular, under certain...

  11. Stability estimates for hp spectral element methods for elliptic ...

    Indian Academy of Sciences (India)

    ... parallel preconditioners and error estimates for the solution of the minimization problem which are nearly optimal as the condition number of the preconditioned system is polylogarithmic in , the number of processors and the number of degrees of freedom in each variable on each element. Moreover if the data is analytic ...

  12. A stabilised nodal spectral element method for fully nonlinear water waves

    DEFF Research Database (Denmark)

    Engsig-Karup, Allan Peter; Eskilsson, C.; Bigoni, Daniele

    2016-01-01

    can cause severe aliasing problems and consequently numerical instability for marginally resolved or very steep waves. We show how the scheme can be stabilised through a combination of over-integration of the Galerkin projections and a mild spectral filtering on a per element basis. This effectively......We present an arbitrary-order spectral element method for general-purpose simulation of non-overturning water waves, described by fully nonlinear potential theory. The method can be viewed as a high-order extension of the classical finite element method proposed by Cai et al. (1998) [5], although...... the numerical implementation differs greatly. Features of the proposed spectral element method include: nodal Lagrange basis functions, a general quadrature-free approach and gradient recovery using global L2 projections. The quartic nonlinear terms present in the Zakharov form of the free surface conditions...

  13. Spectral Analysis of Large Finite Element Problems by Optimization Methods

    Directory of Open Access Journals (Sweden)

    Luca Bergamaschi

    1994-01-01

    Full Text Available Recently an efficient method for the solution of the partial symmetric eigenproblem (DACG, deflated-accelerated conjugate gradient was developed, based on the conjugate gradient (CG minimization of successive Rayleigh quotients over deflated subspaces of decreasing size. In this article four different choices of the coefficient βk required at each DACG iteration for the computation of the new search direction Pk are discussed. The “optimal” choice is the one that yields the same asymptotic convergence rate as the CG scheme applied to the solution of linear systems. Numerical results point out that the optimal βk leads to a very cost effective algorithm in terms of CPU time in all the sample problems presented. Various preconditioners are also analyzed. It is found that DACG using the optimal βk and (LLT−1 as a preconditioner, L being the incomplete Cholesky factor of A, proves a very promising method for the partial eigensolution. It appears to be superior to the Lanczos method in the evaluation of the 40 leftmost eigenpairs of five finite element problems, and particularly for the largest problem, with size equal to 4560, for which the speed gain turns out to fall between 2.5 and 6.0, depending on the eigenpair level.

  14. High-precision solution to the moving load problem using an improved spectral element method

    Science.gov (United States)

    Wen, Shu-Rui; Wu, Zhi-Jing; Lu, Nian-Li

    2018-02-01

    In this paper, the spectral element method (SEM) is improved to solve the moving load problem. In this method, a structure with uniform geometry and material properties is considered as a spectral element, which means that the element number and the degree of freedom can be reduced significantly. Based on the variational method and the Laplace transform theory, the spectral stiffness matrix and the equivalent nodal force of the beam-column element are established. The static Green function is employed to deduce the improved function. The proposed method is applied to two typical engineering practices—the one-span bridge and the horizontal jib of the tower crane. The results have revealed the following. First, the new method can yield extremely high-precision results of the dynamic deflection, the bending moment and the shear force in the moving load problem. In most cases, the relative errors are smaller than 1%. Second, by comparing with the finite element method, one can obtain the highly accurate results using the improved SEM with smaller element numbers. Moreover, the method can be widely used for statically determinate as well as statically indeterminate structures. Third, the dynamic deflection of the twin-lift jib decreases with the increase in the moving load speed, whereas the curvature of the deflection increases. Finally, the dynamic deflection, the bending moment and the shear force of the jib will all increase as the magnitude of the moving load increases.

  15. Spectral element model for 2-D electrostatic fields in a linear synchronous motor

    NARCIS (Netherlands)

    van Beek, T.A.; Curti, M.; Jansen, J.W.; Gysen, B.L.J.; Paulides, J.J.H.; Lomonova, E.A.

    2017-01-01

    This paper presents a fast and accurate 2-D spectral element model for analyzing electric field distributions in linear synchronous motors. The electric field distribution is derived using the electric scalar potential for static cases. The spatial potential and electric field distributions obtained

  16. The next step in coastal numerical models: spectral/hp element methods?

    DEFF Research Database (Denmark)

    Eskilsson, Claes; Engsig-Karup, Allan Peter; Sherwin, Spencer J.

    2005-01-01

    In this paper we outline the application of spectral/hp element methods for modelling nonlinear and dispersive waves. We present one- and two-dimensional test cases for the shallow water equations and Boussinesqtype equations – including highly dispersive Boussinesq-type equations....

  17. Application of Least-Squares Spectral Element Methods to Polynomial Chaos

    NARCIS (Netherlands)

    Vos, P.E.J.; Gerritsma, M.I.

    2006-01-01

    This papers describes the use of the Least-Squares Spectral Element Method to polynomial Chaos to solve stochastic partial differential equations. The method will be described in detail and a comparison will be presented between the least-squares projection and the conventional Galerkin projection.

  18. RenderToolbox3: MATLAB tools that facilitate physically based stimulus rendering for vision research.

    Science.gov (United States)

    Heasly, Benjamin S; Cottaris, Nicolas P; Lichtman, Daniel P; Xiao, Bei; Brainard, David H

    2014-02-07

    RenderToolbox3 provides MATLAB utilities and prescribes a workflow that should be useful to researchers who want to employ graphics in the study of vision and perhaps in other endeavors as well. In particular, RenderToolbox3 facilitates rendering scene families in which various scene attributes and renderer behaviors are manipulated parametrically, enables spectral specification of object reflectance and illuminant spectra, enables the use of physically based material specifications, helps validate renderer output, and converts renderer output to physical units of radiance. This paper describes the design and functionality of the toolbox and discusses several examples that demonstrate its use. We have designed RenderToolbox3 to be portable across computer hardware and operating systems and to be free and open source (except for MATLAB itself). RenderToolbox3 is available at https://github.com/DavidBrainard/RenderToolbox3.

  19. Wavelet-based spectral finite element dynamic analysis for an axially moving Timoshenko beam

    Science.gov (United States)

    Mokhtari, Ali; Mirdamadi, Hamid Reza; Ghayour, Mostafa

    2017-08-01

    In this article, wavelet-based spectral finite element (WSFE) model is formulated for time domain and wave domain dynamic analysis of an axially moving Timoshenko beam subjected to axial pretension. The formulation is similar to conventional FFT-based spectral finite element (SFE) model except that Daubechies wavelet basis functions are used for temporal discretization of the governing partial differential equations into a set of ordinary differential equations. The localized nature of Daubechies wavelet basis functions helps to rule out problems of SFE model due to periodicity assumption, especially during inverse Fourier transformation and back to time domain. The high accuracy of WSFE model is then evaluated by comparing its results with those of conventional finite element and SFE results. The effects of moving beam speed and axial tensile force on vibration and wave characteristics, and static and dynamic stabilities of moving beam are investigated.

  20. Apparatus and method using a holographic optical element for converting a spectral distribution to image points

    Science.gov (United States)

    McGill, Matthew J. (Inventor); Scott, Vibart S. (Inventor); Marzouk, Marzouk (Inventor)

    2001-01-01

    A holographic optical element transforms a spectral distribution of light to image points. The element comprises areas, each of which acts as a separate lens to image the light incident in its area to an image point. Each area contains the recorded hologram of a point source object. The image points can be made to lie in a line in the same focal plane so as to align with a linear array detector. A version of the element has been developed that has concentric equal areas to match the circular fringe pattern of a Fabry-Perot interferometer. The element has high transmission efficiency, and when coupled with high quantum efficiency solid state detectors, provides an efficient photon-collecting detection system. The element may be used as part of the detection system in a direct detection Doppler lidar system or multiple field of view lidar system.

  1. Spectral element method for elastic and acoustic waves in frequency domain

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Linlin; Zhou, Yuanguo; Wang, Jia-Min; Zhuang, Mingwei [Institute of Electromagnetics and Acoustics, and Department of Electronic Science, Xiamen, 361005 (China); Liu, Na, E-mail: liuna@xmu.edu.cn [Institute of Electromagnetics and Acoustics, and Department of Electronic Science, Xiamen, 361005 (China); Liu, Qing Huo, E-mail: qhliu@duke.edu [Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708 (United States)

    2016-12-15

    Numerical techniques in time domain are widespread in seismic and acoustic modeling. In some applications, however, frequency-domain techniques can be advantageous over the time-domain approach when narrow band results are desired, especially if multiple sources can be handled more conveniently in the frequency domain. Moreover, the medium attenuation effects can be more accurately and conveniently modeled in the frequency domain. In this paper, we present a spectral-element method (SEM) in frequency domain to simulate elastic and acoustic waves in anisotropic, heterogeneous, and lossy media. The SEM is based upon the finite-element framework and has exponential convergence because of the use of GLL basis functions. The anisotropic perfectly matched layer is employed to truncate the boundary for unbounded problems. Compared with the conventional finite-element method, the number of unknowns in the SEM is significantly reduced, and higher order accuracy is obtained due to its spectral accuracy. To account for the acoustic-solid interaction, the domain decomposition method (DDM) based upon the discontinuous Galerkin spectral-element method is proposed. Numerical experiments show the proposed method can be an efficient alternative for accurate calculation of elastic and acoustic waves in frequency domain.

  2. The strongest spectral lines of stable elements with other interfering elements in compiled and plotted version

    International Nuclear Information System (INIS)

    Bauer, M.; Weitkamp, C.

    1977-01-01

    The strongest spectra lines of the 85 stable chemical elements have been compiled and plotted along with lines from other elements that may interfere in applications like spectroscopic multielement analysis. For each line a wavelength range of +- 0.25 A.U. around the line of interest has been considered. The tables contain the wavelength, intensity and assignment to an ionization state of the emitting atom, the plots visualize the lines with a doppler broadening corresponding to 8,000 K. (orig.) [de

  3. Nonlinear Legendre Spectral Finite Elements for Wind Turbine Blade Dynamics: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q.; Sprague, M. A.; Jonkman, J.; Johnson, N.

    2014-01-01

    This paper presents a numerical implementation and examination of new wind turbine blade finite element model based on Geometrically Exact Beam Theory (GEBT) and a high-order spectral finite element method. The displacement-based GEBT is presented, which includes the coupling effects that exist in composite structures and geometric nonlinearity. Legendre spectral finite elements (LSFEs) are high-order finite elements with nodes located at the Gauss-Legendre-Lobatto points. LSFEs can be an order of magnitude more efficient that low-order finite elements for a given accuracy level. Interpolation of the three-dimensional rotation, a major technical barrier in large-deformation simulation, is discussed in the context of LSFEs. It is shown, by numerical example, that the high-order LSFEs, where weak forms are evaluated with nodal quadrature, do not suffer from a drawback that exists in low-order finite elements where the tangent-stiffness matrix is calculated at the Gauss points. Finally, the new LSFE code is implemented in the new FAST Modularization Framework for dynamic simulation of highly flexible composite-material wind turbine blades. The framework allows for fully interactive simulations of turbine blades in operating conditions. Numerical examples showing validation and LSFE performance will be provided in the final paper.

  4. High-throughput flow injection analysis mass spectroscopy with networked delivery of color-rendered results. 2. Three-dimensional spectral mapping of 96-well combinatorial chemistry racks.

    Science.gov (United States)

    Görlach, E; Richmond, R; Lewis, I

    1998-08-01

    For the last two years, the mass spectroscopy section of the Novartis Pharma Research Core Technology group has analyzed tens of thousands of multiple parallel synthesis samples from the Novartis Pharma Combinatorial Chemistry program, using an in-house developed automated high-throughput flow injection analysis electrospray ionization mass spectroscopy system. The electrospray spectra of these samples reflect the many structures present after the cleavage step from the solid support. The overall success of the sequential synthesis is mirrored in the purity of the expected end product, but the partial success of individual synthesis steps is evident in the impurities in the mass spectrum. However this latter reaction information, which is of considerable utility to the combinatorial chemist, is effectively hidden from view by the very large number of analyzed samples. This information is now revealed at the workbench of the combinatorial chemist by a novel three-dimensional display of each rack's complete mass spectral ion current using the in-house RackViewer Visual Basic application. Colorization of "forbidden loss" and "forbidden gas-adduct" zones, normalization to expected monoisotopic molecular weight, colorization of ionization intensity, and sorting by row or column were used in combination to highlight systematic patterns in the mass spectroscopy data.

  5. Spectral decomposition in advection-diffusion analysis by finite element methods

    International Nuclear Information System (INIS)

    Nickell, R.E.; Gartling, D.K.; Strang, G.

    1978-01-01

    In a recent study of the convergence properties of finite element methods in nonlinear fluid mechanics, an indirect approach was taken. A two-dimensional example with a known exact solution was chosen as the vehicle for the study, and various mesh refinements were tested in an attempt to extract information on the effect of the local Reynolds number. However, more direct approaches are usually preferred. In this study one such direct approach is followed, based upon the spectral decomposition of the solution operator. Spectral decomposition is widely employed as a solution technique for linear structural dynamics problems and can be applied readily to linear, transient heat transfer analysis; in this case, the extension to nonlinear problems is of interest. It was shown previously that spectral techniques were applicable to stiff systems of rate equations, while recent studies of geometrically and materially nonlinear structural dynamics have demonstrated the increased information content of the numerical results. The use of spectral decomposition in nonlinear problems of heat and mass transfer would be expected to yield equally increased flow of information to the analyst, and this information could include a quantitative comparison of various solution strategies, meshes, and element hierarchies

  6. A three-dimensional spectral element model for the solution of the hydrostatic primitive equations

    CERN Document Server

    Iskandarani, M; Levin, J C

    2003-01-01

    We present a spectral element model to solve the hydrostatic primitive equations governing large-scale geophysical flows. The highlights of this new model include unstructured grids, dual h-p paths to convergence, and good scalability characteristics on present day parallel computers including Beowulf-class systems. The behavior of the model is assessed on three process-oriented test problems involving wave propagation, gravitational adjustment, and nonlinear flow rectification, respectively. The first of these test problems is a study of the convergence properties of the model when simulating the linear propagation of baroclinic Kelvin waves. The second is an intercomparison of spectral element and finite-difference model solutions to the adjustment of a density front in a straight channel. Finally, the third problem considers the comparison of model results to measurements obtained from a laboratory simulation of flow around a submarine canyon. The aforementioned tests demonstrate the good performance of th...

  7. Multiscale finite element methods for high-contrast problems using local spectral basis functions

    KAUST Repository

    Efendiev, Yalchin

    2011-02-01

    In this paper we study multiscale finite element methods (MsFEMs) using spectral multiscale basis functions that are designed for high-contrast problems. Multiscale basis functions are constructed using eigenvectors of a carefully selected local spectral problem. This local spectral problem strongly depends on the choice of initial partition of unity functions. The resulting space enriches the initial multiscale space using eigenvectors of local spectral problem. The eigenvectors corresponding to small, asymptotically vanishing, eigenvalues detect important features of the solutions that are not captured by initial multiscale basis functions. Multiscale basis functions are constructed such that they span these eigenfunctions that correspond to small, asymptotically vanishing, eigenvalues. We present a convergence study that shows that the convergence rate (in energy norm) is proportional to (H/Λ*)1/2, where Λ* is proportional to the minimum of the eigenvalues that the corresponding eigenvectors are not included in the coarse space. Thus, we would like to reach to a larger eigenvalue with a smaller coarse space. This is accomplished with a careful choice of initial multiscale basis functions and the setup of the eigenvalue problems. Numerical results are presented to back-up our theoretical results and to show higher accuracy of MsFEMs with spectral multiscale basis functions. We also present a hierarchical construction of the eigenvectors that provides CPU savings. © 2010.

  8. Spectral interference of zirconium on 24 analyte elements using CCD based ICP-AES technique

    International Nuclear Information System (INIS)

    Adya, V.C.; Sengupta, Arijit; Godbole, S.V.

    2014-01-01

    In the present studies, the spectral interference of zirconium on different analytical lines of 24 critical analytes using CCD based ICP-AES technique is described. Suitable analytical lines for zirconium were identified along with their detection limits. The sensitivity and the detection limits of analytical channels for different elements in presence of Zr matrix were calculated. Subsequently analytical lines with least interference from Zr and better detection limits were selected for their determinations. (author)

  9. Co-simulation coupling spectral/finite elements for 3D soil/structure interaction problems

    Science.gov (United States)

    Zuchowski, Loïc; Brun, Michael; De Martin, Florent

    2018-05-01

    The coupling between an implicit finite elements (FE) code and an explicit spectral elements (SE) code has been explored for solving the elastic wave propagation in the case of soil/structure interaction problem. The coupling approach is based on domain decomposition methods in transient dynamics. The spatial coupling at the interface is managed by a standard coupling mortar approach, whereas the time integration is dealt with an hybrid asynchronous time integrator. An external coupling software, handling the interface problem, has been set up in order to couple the FE software Code_Aster with the SE software EFISPEC3D.

  10. The spectral element approach for the solution of neutron transport problems

    International Nuclear Information System (INIS)

    Barbarino, A.; Dulla, S.; Ravetto, P.; Mund, E.H.

    2011-01-01

    In this paper a possible application of the Spectral Element Method to neutron transport problems is presented. The basic features of the numerical scheme on the one-dimensional diffusion equation are illustrated. Then, the AN model for neutron transport is introduced, and the basic steps for the construction of a bi-dimensional solver are described. The AN equations are chosen for their structure, involving a system of coupled elliptic-type equations. Some calculations are carried out on typical benchmark problems and results are compared with the Finite Element Method, in order to evaluate their performances. (author)

  11. The Spectral/hp-Finite Element Method for Partial Differential Equations

    DEFF Research Database (Denmark)

    Engsig-Karup, Allan Peter

    2009-01-01

    dimensions. In the course the chosen programming environment is Matlab, however, this is by no means a necessary requirement. The mathematical level needed to grasp the details of this set of notes requires an elementary background in mathematical analysis and linear algebra. Each chapter is supplemented......This set of lecture notes provides an elementary introduction to both the classical Finite Element Method (FEM) and the extended Spectral/$hp$-Finite Element Method for solving Partial Differential Equations (PDEs). Many problems in science and engineering can be formulated mathematically...

  12. A deflation based parallel algorithm for spectral element solution of the incompressible Navier-Stokes equations

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, P.F. [Brown Univ., Providence, RI (United States)

    1996-12-31

    Efficient solution of the Navier-Stokes equations in complex domains is dependent upon the availability of fast solvers for sparse linear systems. For unsteady incompressible flows, the pressure operator is the leading contributor to stiffness, as the characteristic propagation speed is infinite. In the context of operator splitting formulations, it is the pressure solve which is the most computationally challenging, despite its elliptic origins. We seek to improve existing spectral element iterative methods for the pressure solve in order to overcome the slow convergence frequently observed in the presence of highly refined grids or high-aspect ratio elements.

  13. Spectral/hp least-squares finite element formulation for the Navier-Stokes equations

    International Nuclear Information System (INIS)

    Pontaza, J.P.; Reddy, J.N.

    2003-01-01

    We consider the application of least-squares finite element models combined with spectral/hp methods for the numerical solution of viscous flow problems. The paper presents the formulation, validation, and application of a spectral/hp algorithm to the numerical solution of the Navier-Stokes equations governing two- and three-dimensional stationary incompressible and low-speed compressible flows. The Navier-Stokes equations are expressed as an equivalent set of first-order equations by introducing vorticity or velocity gradients as additional independent variables and the least-squares method is used to develop the finite element model. High-order element expansions are used to construct the discrete model. The discrete model thus obtained is linearized by Newton's method, resulting in a linear system of equations with a symmetric positive definite coefficient matrix that is solved in a fully coupled manner by a preconditioned conjugate gradient method. Spectral convergence of the L 2 least-squares functional and L 2 error norms is verified using smooth solutions to the two-dimensional stationary Poisson and incompressible Navier-Stokes equations. Numerical results for flow over a backward-facing step, steady flow past a circular cylinder, three-dimensional lid-driven cavity flow, and compressible buoyant flow inside a square enclosure are presented to demonstrate the predictive capability and robustness of the proposed formulation

  14. Spectral element method for band-structure calculations of 3D phononic crystals

    International Nuclear Information System (INIS)

    Shi, Linlin; Liu, Na; Zhou, Jianyang; Zhou, Yuanguo; Wang, Jiamin; Liu, Qing Huo

    2016-01-01

    The spectral element method (SEM) is a special kind of high-order finite element method (FEM) which combines the flexibility of a finite element method with the accuracy of a spectral method. In contrast to the traditional FEM, the SEM exhibits advantages in the high-order accuracy as the error decreases exponentially with the increase of interpolation degree by employing the Gauss–Lobatto–Legendre (GLL) polynomials as basis functions. In this study, the spectral element method is developed for the first time for the determination of band structures of 3D isotropic/anisotropic phononic crystals (PCs). Based on the Bloch theorem, we present a novel, intuitive discretization formulation for Navier equation in the SEM scheme for periodic media. By virtue of using the orthogonal Legendre polynomials, the generalized eigenvalue problem is converted to a regular one in our SEM implementation to improve the efficiency. Besides, according to the specific geometry structure, 8-node and 27-node hexahedral elements as well as an analytic mesh have been used to accurately capture curved PC models in our SEM scheme. To verify its accuracy and efficiency, this study analyses the phononic-crystal plates with square and triangular lattice arrangements, and the 3D cubic phononic crystals consisting of simple cubic (SC), bulk central cubic (BCC) and faced central cubic (FCC) lattices with isotropic or anisotropic scatters. All the numerical results considered demonstrate that SEM is superior to the conventional FEM and can be an efficient alternative method for accurate determination of band structures of 3D phononic crystals. (paper)

  15. Element-specific spectral imaging of multiple contrast agents: a phantom study

    Science.gov (United States)

    Panta, R. K.; Bell, S. T.; Healy, J. L.; Aamir, R.; Bateman, C. J.; Moghiseh, M.; Butler, A. P. H.; Anderson, N. G.

    2018-02-01

    This work demonstrates the feasibility of simultaneous discrimination of multiple contrast agents based on their element-specific and energy-dependent X-ray attenuation properties using a pre-clinical photon-counting spectral CT. We used a photon-counting based pre-clinical spectral CT scanner with four energy thresholds to measure the X-ray attenuation properties of various concentrations of iodine (9, 18 and 36 mg/ml), gadolinium (2, 4 and 8 mg/ml) and gold (2, 4 and 8 mg/ml) based contrast agents, calcium chloride (140 and 280 mg/ml) and water. We evaluated the spectral imaging performances of different energy threshold schemes between 25 to 82 keV at 118 kVp, based on K-factor and signal-to-noise ratio and ranked them. K-factor was defined as the X-ray attenuation in the K-edge containing energy range divided by the X-ray attenuation in the preceding energy range, expressed as a percentage. We evaluated the effectiveness of the optimised energy selection to discriminate all three contrast agents in a phantom of 33 mm diameter. A photon-counting spectral CT using four energy thresholds of 27, 33, 49 and 81 keV at 118 kVp simultaneously discriminated three contrast agents based on iodine, gadolinium and gold at various concentrations using their K-edge and energy-dependent X-ray attenuation features in a single scan. A ranking method to evaluate spectral imaging performance enabled energy thresholds to be optimised to discriminate iodine, gadolinium and gold contrast agents in a single spectral CT scan. Simultaneous discrimination of multiple contrast agents in a single scan is likely to open up new possibilities of improving the accuracy of disease diagnosis by simultaneously imaging multiple bio-markers each labelled with a nano-contrast agent.

  16. The spectral element method for static neutron transport in AN approximation. Part I

    International Nuclear Information System (INIS)

    Barbarino, A.; Dulla, S.; Mund, E.H.; Ravetto, P.

    2013-01-01

    Highlights: ► Spectral elements methods (SEMs) are extended for the neutronics of nuclear reactor cores. ► The second-order, A N formulation of neutron trasport is adopted. ► Results for classical benchmark cases in 2D are presented and compared to finite elements. ► The advantages of SEM in terms of precision and convergence rate are illustrated. ► SEM consitutes a promising approach for the solution of neutron transport problems. - Abstract: Spectral elements methods provide very accurate solutions of elliptic problems. In this paper we apply the method to the A N (i.e. SP 2N−1 ) approximation of neutron transport. Numerical results for classical benchmark cases highlight its performance in comparison with finite element computations, in terms of accuracy per degree of freedom and convergence rate. All calculations presented in this paper refer to two-dimensional problems. The method can easily be extended to three-dimensional cases. The results illustrate promising features of the method for more complex transport problems

  17. A spectral element-FCT method for the compressible Euler equations

    International Nuclear Information System (INIS)

    Giannakouros, J.; Karniadakis, G.E.

    1994-01-01

    A new algorithm based on spectral element discretizations and flux-corrected transport concepts is developed for the solution of the Euler equations of inviscid compressible fluid flow. A conservative formulation is proposed based on one- and two-dimensional cell-averaging and reconstruction procedures, which employ a staggered mesh of Gauss-Chebyshev and Gauss-Lobatto-Chebyshev collocation points. Particular emphasis is placed on the construction of robust boundary and interfacial conditions in one- and two-dimensions. It is demonstrated through shock-tube problems and two-dimensional simulations that the proposed algorithm leads to stable, non-oscillatory solutions of high accuracy. Of particular importance is the fact that dispersion errors are minimal, as show through experiments. From the operational point of view, casting the method in a spectral element formulation provides flexibility in the discretization, since a variable number of macro-elements or collocation points per element can be employed to accomodate both accuracy and geometric requirements

  18. Dynamic analysis of smart composite beams by using the frequency domain spectral element method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Il Wook; Lee, Usik [Inha Univ., Incheon (Korea, Republic of)

    2012-08-15

    To excite or measure the dynamic responses of a laminated composite structure for the active controls of vibrations or noises, wafertype piezoelectric transducers are often bonded on the surface of the composite structure to form a multi layer smart composite structure. Thus, for such smart composite structures, it is very important to develop and use a very reliable mathematical and/or computational model for predicting accurate dynamic characteristics. In this paper, the axial-bending coupled equations of motion and boundary conditions are derived for two layer smart composite beams by using the Hamilton's principle with Lagrange multipliers. The spectral element model is then formulated in the frequency domain by using the variation approach. Through some numerical examples, the extremely high accuracy of the present spectral element model is verified by comparing with the solutions by the conventional finite element model provided in this paper. The effects of the lay up of composite laminates and surface bonded wafer type piezoelectric (PZT) layer on the dynamics and wave characteristics of smart composite beams are investigated. The effective constraint forces at the interface between the base beam and PZT layer are also investigated via Lagrange multipliers.

  19. Towards an Entropy Stable Spectral Element Framework for Computational Fluid Dynamics

    KAUST Repository

    Carpenter, Mark H.

    2016-01-04

    Nonlinearly stable finite element methods of arbitrary type and order, are currently unavailable for discretizations of the compressible Navier-Stokes equations. Summation-by-parts (SBP) entropy stability analysis provides a means of constructing nonlinearly stable discrete operators of arbitrary order, but is currently limited to simple element types. Herein, recent progress is reported, on developing entropy-stable (SS) discontinuous spectral collocation formulations for hexahedral elements. Two complementary efforts are discussed. The first effort generalizes previous SS spectral collocation work to extend the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to tensor product Legendre-Gauss (LG) points. The LG and LGL point formulations are compared on a series of test problems. Both the LGL and LG operators are of comparable efficiency and robustness, as is demonstrated using test problems for which conventional FEM techniques suffer instability. The second effort extends previous work on entropy stability to include p-refinement at nonconforming interfaces. A generalization of existing entropy stability theory is required to accommodate the nuances of fully multidimensional SBP operators. The entropy stability of the compressible Euler equations on nonconforming interfaces is demonstrated using the newly developed LG operators and multidimensional interface interpolation operators. Preliminary studies suggest design order accuracy at nonconforming interfaces.

  20. Raman spectral, elemental, crystallinity, and oxygen-isotope variations in conodont apatite during diagenesis

    Science.gov (United States)

    Zhang, Lei; Cao, Ling; Zhao, Laishi; Algeo, Thomas J.; Chen, Zhong-Qiang; Li, Zhihong; Lv, Zhengyi; Wang, Xiangdong

    2017-08-01

    Conodont apatite has long been used in paleoenvironmental studies, often with minimal evaluation of the influence of diagenesis on measured elemental and isotopic signals. In this study, we evaluate diagenetic influences on conodonts using an integrated set of analytical techniques. A total of 92 points in 19 coniform conodonts from Ordovician marine units of South China were analyzed by micro-laser Raman spectroscopy (M-LRS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), high-resolution X-ray microdiffraction (HXRD), and secondary ion mass spectrometry (SIMS). Each conodont element was analyzed along its full length, including the albid crown, hyaline crown, and basal body, in either a whole specimen (i.e., reflecting the composition of its outer layer) or a split specimen (i.e., reflecting the composition of its interior). In the conodonts of this study, the outer surfaces consist of hydroxyfluorapatite and the interiors of strontian hydroxyfluorapatite. Ionic substitutions resulted in characteristic Raman spectral shifts in the position (SS1) and width (SS2) of the ν1-PO43- stretching band. Although multiple elements were enriched (Sr2+, Mg2+) and depleted (Fe3+, Mn2+, Ca2+) during diagenesis, geochemical modeling constraints and known Raman spectral patterns suggest that Sr uptake was the dominant influence on diagenetic redshifts of SS1. All study specimens show lower SS2 values than modern bioapatite and synthetic apatite, suggesting that band width decreases with time in ancient bioapatite, possibly through an annealing process that produces larger, more uniform crystal domains. Most specimens consist mainly of amorphous or poorly crystalline apatite, which is inferred to represent the original microstructure of conodonts. In a subset of specimens, some tissues (especially albid crown) exhibit an increased degree of crystallinity developed through aggrading neomorphism. However, no systematic relationship was observed between

  1. [Analysis of the mineral elements of Lactuca sativa under the condition of different spectral components].

    Science.gov (United States)

    Chen, Xiao-Li; Guo, Wen-Zhong; Xue, Xu-Zhang; Wang, Li-Chun; Li, Liang; Chen, Fei

    2013-08-01

    Mineral elements absorption and content of Lactuca sativa under different spectral component conditions were studied by ICP-AES technology. The results showed that: (1) For Lactuca sativa, the average proportion for Ca : Mg : K : Na : P was 5.5 : 2.5 : 2.3 : 1.5 : 1.0, the average proportion for Fe : Mn : Zn : Cu : B was 25.9 : 5.9 : 2.8 : 1.1 : 1.0; (2) The absorptions for K, P, Ca, Mg and B are the largest under the LED treatment R/B = 1 : 2.75, red light from fluorescent lamps and LED can both promote the absorptions of Fe and Cu; (3)The LED treatments exhibiting relatively higher content of mineral elements are R/B = 1 : 2.75 and R/W = 1 : 1 while higher dry matter accumulations are R/B = 1 : 2.75 and B/W = 1 : 1.

  2. Computational Performance of a Parallelized Three-Dimensional High-Order Spectral Element Toolbox

    Science.gov (United States)

    Bosshard, Christoph; Bouffanais, Roland; Clémençon, Christian; Deville, Michel O.; Fiétier, Nicolas; Gruber, Ralf; Kehtari, Sohrab; Keller, Vincent; Latt, Jonas

    In this paper, a comprehensive performance review of an MPI-based high-order three-dimensional spectral element method C++ toolbox is presented. The focus is put on the performance evaluation of several aspects with a particular emphasis on the parallel efficiency. The performance evaluation is analyzed with help of a time prediction model based on a parameterization of the application and the hardware resources. A tailor-made CFD computation benchmark case is introduced and used to carry out this review, stressing the particular interest for clusters with up to 8192 cores. Some problems in the parallel implementation have been detected and corrected. The theoretical complexities with respect to the number of elements, to the polynomial degree, and to communication needs are correctly reproduced. It is concluded that this type of code has a nearly perfect speed up on machines with thousands of cores, and is ready to make the step to next-generation petaflop machines.

  3. Frequency domain finite-element and spectral-element acoustic wave modeling using absorbing boundaries and perfectly matched layer

    Science.gov (United States)

    Rahimi Dalkhani, Amin; Javaherian, Abdolrahim; Mahdavi Basir, Hadi

    2018-04-01

    Wave propagation modeling as a vital tool in seismology can be done via several different numerical methods among them are finite-difference, finite-element, and spectral-element methods (FDM, FEM and SEM). Some advanced applications in seismic exploration benefit the frequency domain modeling. Regarding flexibility in complex geological models and dealing with the free surface boundary condition, we studied the frequency domain acoustic wave equation using FEM and SEM. The results demonstrated that the frequency domain FEM and SEM have a good accuracy and numerical efficiency with the second order interpolation polynomials. Furthermore, we developed the second order Clayton and Engquist absorbing boundary condition (CE-ABC2) and compared it with the perfectly matched layer (PML) for the frequency domain FEM and SEM. In spite of PML method, CE-ABC2 does not add any additional computational cost to the modeling except assembling boundary matrices. As a result, considering CE-ABC2 is more efficient than PML for the frequency domain acoustic wave propagation modeling especially when computational cost is high and high-level absorbing performance is unnecessary.

  4. Discrete conservation properties for shallow water flows using mixed mimetic spectral elements

    Science.gov (United States)

    Lee, D.; Palha, A.; Gerritsma, M.

    2018-03-01

    A mixed mimetic spectral element method is applied to solve the rotating shallow water equations. The mixed method uses the recently developed spectral element histopolation functions, which exactly satisfy the fundamental theorem of calculus with respect to the standard Lagrange basis functions in one dimension. These are used to construct tensor product solution spaces which satisfy the generalized Stokes theorem, as well as the annihilation of the gradient operator by the curl and the curl by the divergence. This allows for the exact conservation of first order moments (mass, vorticity), as well as higher moments (energy, potential enstrophy), subject to the truncation error of the time stepping scheme. The continuity equation is solved in the strong form, such that mass conservation holds point wise, while the momentum equation is solved in the weak form such that vorticity is globally conserved. While mass, vorticity and energy conservation hold for any quadrature rule, potential enstrophy conservation is dependent on exact spatial integration. The method possesses a weak form statement of geostrophic balance due to the compatible nature of the solution spaces and arbitrarily high order spatial error convergence.

  5. Video-based rendering

    CERN Document Server

    Magnor, Marcus A

    2005-01-01

    Driven by consumer-market applications that enjoy steadily increasing economic importance, graphics hardware and rendering algorithms are a central focus of computer graphics research. Video-based rendering is an approach that aims to overcome the current bottleneck in the time-consuming modeling process and has applications in areas such as computer games, special effects, and interactive TV. This book offers an in-depth introduction to video-based rendering, a rapidly developing new interdisciplinary topic employing techniques from computer graphics, computer vision, and telecommunication en

  6. Spectral-element Method for 3D Marine Controlled-source EM Modeling

    Science.gov (United States)

    Liu, L.; Yin, C.; Zhang, B., Sr.; Liu, Y.; Qiu, C.; Huang, X.; Zhu, J.

    2017-12-01

    As one of the predrill reservoir appraisal methods, marine controlled-source EM (MCSEM) has been widely used in mapping oil reservoirs to reduce risk of deep water exploration. With the technical development of MCSEM, the need for improved forward modeling tools has become evident. We introduce in this paper spectral element method (SEM) for 3D MCSEM modeling. It combines the flexibility of finite-element and high accuracy of spectral method. We use Galerkin weighted residual method to discretize the vector Helmholtz equation, where the curl-conforming Gauss-Lobatto-Chebyshev (GLC) polynomials are chosen as vector basis functions. As a kind of high-order complete orthogonal polynomials, the GLC have the characteristic of exponential convergence. This helps derive the matrix elements analytically and improves the modeling accuracy. Numerical 1D models using SEM with different orders show that SEM method delivers accurate results. With increasing SEM orders, the modeling accuracy improves largely. Further we compare our SEM with finite-difference (FD) method for a 3D reservoir model (Figure 1). The results show that SEM method is more effective than FD method. Only when the mesh is fine enough, can FD achieve the same accuracy of SEM. Therefore, to obtain the same precision, SEM greatly reduces the degrees of freedom and cost. Numerical experiments with different models (not shown here) demonstrate that SEM is an efficient and effective tool for MSCEM modeling that has significant advantages over traditional numerical methods.This research is supported by Key Program of National Natural Science Foundation of China (41530320), China Natural Science Foundation for Young Scientists (41404093), and Key National Research Project of China (2016YFC0303100, 2017YFC0601900).

  7. Higher-order triangular spectral element method with optimized cubature points for seismic wavefield modeling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Youshan, E-mail: ysliu@mail.iggcas.ac.cn [State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 (China); Teng, Jiwen, E-mail: jwteng@mail.iggcas.ac.cn [State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 (China); Xu, Tao, E-mail: xutao@mail.iggcas.ac.cn [State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 (China); CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101 (China); Badal, José, E-mail: badal@unizar.es [Physics of the Earth, Sciences B, University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain)

    2017-05-01

    The mass-lumped method avoids the cost of inverting the mass matrix and simultaneously maintains spatial accuracy by adopting additional interior integration points, known as cubature points. To date, such points are only known analytically in tensor domains, such as quadrilateral or hexahedral elements. Thus, the diagonal-mass-matrix spectral element method (SEM) in non-tensor domains always relies on numerically computed interpolation points or quadrature points. However, only the cubature points for degrees 1 to 6 are known, which is the reason that we have developed a p-norm-based optimization algorithm to obtain higher-order cubature points. In this way, we obtain and tabulate new cubature points with all positive integration weights for degrees 7 to 9. The dispersion analysis illustrates that the dispersion relation determined from the new optimized cubature points is comparable to that of the mass and stiffness matrices obtained by exact integration. Simultaneously, the Lebesgue constant for the new optimized cubature points indicates its surprisingly good interpolation properties. As a result, such points provide both good interpolation properties and integration accuracy. The Courant–Friedrichs–Lewy (CFL) numbers are tabulated for the conventional Fekete-based triangular spectral element (TSEM), the TSEM with exact integration, and the optimized cubature-based TSEM (OTSEM). A complementary study demonstrates the spectral convergence of the OTSEM. A numerical example conducted on a half-space model demonstrates that the OTSEM improves the accuracy by approximately one order of magnitude compared to the conventional Fekete-based TSEM. In particular, the accuracy of the 7th-order OTSEM is even higher than that of the 14th-order Fekete-based TSEM. Furthermore, the OTSEM produces a result that can compete in accuracy with the quadrilateral SEM (QSEM). The high accuracy of the OTSEM is also tested with a non-flat topography model. In terms of computational

  8. Higher-order triangular spectral element method with optimized cubature points for seismic wavefield modeling

    Science.gov (United States)

    Liu, Youshan; Teng, Jiwen; Xu, Tao; Badal, José

    2017-05-01

    The mass-lumped method avoids the cost of inverting the mass matrix and simultaneously maintains spatial accuracy by adopting additional interior integration points, known as cubature points. To date, such points are only known analytically in tensor domains, such as quadrilateral or hexahedral elements. Thus, the diagonal-mass-matrix spectral element method (SEM) in non-tensor domains always relies on numerically computed interpolation points or quadrature points. However, only the cubature points for degrees 1 to 6 are known, which is the reason that we have developed a p-norm-based optimization algorithm to obtain higher-order cubature points. In this way, we obtain and tabulate new cubature points with all positive integration weights for degrees 7 to 9. The dispersion analysis illustrates that the dispersion relation determined from the new optimized cubature points is comparable to that of the mass and stiffness matrices obtained by exact integration. Simultaneously, the Lebesgue constant for the new optimized cubature points indicates its surprisingly good interpolation properties. As a result, such points provide both good interpolation properties and integration accuracy. The Courant-Friedrichs-Lewy (CFL) numbers are tabulated for the conventional Fekete-based triangular spectral element (TSEM), the TSEM with exact integration, and the optimized cubature-based TSEM (OTSEM). A complementary study demonstrates the spectral convergence of the OTSEM. A numerical example conducted on a half-space model demonstrates that the OTSEM improves the accuracy by approximately one order of magnitude compared to the conventional Fekete-based TSEM. In particular, the accuracy of the 7th-order OTSEM is even higher than that of the 14th-order Fekete-based TSEM. Furthermore, the OTSEM produces a result that can compete in accuracy with the quadrilateral SEM (QSEM). The high accuracy of the OTSEM is also tested with a non-flat topography model. In terms of computational

  9. Higher-order triangular spectral element method with optimized cubature points for seismic wavefield modeling

    International Nuclear Information System (INIS)

    Liu, Youshan; Teng, Jiwen; Xu, Tao; Badal, José

    2017-01-01

    The mass-lumped method avoids the cost of inverting the mass matrix and simultaneously maintains spatial accuracy by adopting additional interior integration points, known as cubature points. To date, such points are only known analytically in tensor domains, such as quadrilateral or hexahedral elements. Thus, the diagonal-mass-matrix spectral element method (SEM) in non-tensor domains always relies on numerically computed interpolation points or quadrature points. However, only the cubature points for degrees 1 to 6 are known, which is the reason that we have developed a p-norm-based optimization algorithm to obtain higher-order cubature points. In this way, we obtain and tabulate new cubature points with all positive integration weights for degrees 7 to 9. The dispersion analysis illustrates that the dispersion relation determined from the new optimized cubature points is comparable to that of the mass and stiffness matrices obtained by exact integration. Simultaneously, the Lebesgue constant for the new optimized cubature points indicates its surprisingly good interpolation properties. As a result, such points provide both good interpolation properties and integration accuracy. The Courant–Friedrichs–Lewy (CFL) numbers are tabulated for the conventional Fekete-based triangular spectral element (TSEM), the TSEM with exact integration, and the optimized cubature-based TSEM (OTSEM). A complementary study demonstrates the spectral convergence of the OTSEM. A numerical example conducted on a half-space model demonstrates that the OTSEM improves the accuracy by approximately one order of magnitude compared to the conventional Fekete-based TSEM. In particular, the accuracy of the 7th-order OTSEM is even higher than that of the 14th-order Fekete-based TSEM. Furthermore, the OTSEM produces a result that can compete in accuracy with the quadrilateral SEM (QSEM). The high accuracy of the OTSEM is also tested with a non-flat topography model. In terms of computational

  10. Rendering of Gemstones

    OpenAIRE

    Krtek, Lukáš

    2012-01-01

    The distinctive appearance of gemstones is caused by the way light reflects and refracts multiple times inside of them. The goal of this thesis is to design and implement an application for photorealistic rendering of gems. The most important effects we aim for are realistic dispersion of light and refractive caustics. For rendering we use well-known algorithm of path tracing with an experimental modification for faster computation of caustic effects. In this thesis we also design and impleme...

  11. Towards an Entropy Stable Spectral Element Framework for Computational Fluid Dynamics

    Science.gov (United States)

    Carpenter, Mark H.; Parsani, Matteo; Fisher, Travis C.; Nielsen, Eric J.

    2016-01-01

    Entropy stable (SS) discontinuous spectral collocation formulations of any order are developed for the compressible Navier-Stokes equations on hexahedral elements. Recent progress on two complementary efforts is presented. The first effort is a generalization of previous SS spectral collocation work to extend the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to tensor product Legendre-Gauss (LG) points. The LG and LGL point formulations are compared on a series of test problems. Although being more costly to implement, it is shown that the LG operators are significantly more accurate on comparable grids. Both the LGL and LG operators are of comparable efficiency and robustness, as is demonstrated using test problems for which conventional FEM techniques suffer instability. The second effort generalizes previous SS work to include the possibility of p-refinement at non-conforming interfaces. A generalization of existing entropy stability machinery is developed to accommodate the nuances of fully multi-dimensional summation-by-parts (SBP) operators. The entropy stability of the compressible Euler equations on non-conforming interfaces is demonstrated using the newly developed LG operators and multi-dimensional interface interpolation operators.

  12. A spectral element method with adaptive segmentation for accurately simulating extracellular electrical stimulation of neurons.

    Science.gov (United States)

    Eiber, Calvin D; Dokos, Socrates; Lovell, Nigel H; Suaning, Gregg J

    2017-05-01

    The capacity to quickly and accurately simulate extracellular stimulation of neurons is essential to the design of next-generation neural prostheses. Existing platforms for simulating neurons are largely based on finite-difference techniques; due to the complex geometries involved, the more powerful spectral or differential quadrature techniques cannot be applied directly. This paper presents a mathematical basis for the application of a spectral element method to the problem of simulating the extracellular stimulation of retinal neurons, which is readily extensible to neural fibers of any kind. The activating function formalism is extended to arbitrary neuron geometries, and a segmentation method to guarantee an appropriate choice of collocation points is presented. Differential quadrature may then be applied to efficiently solve the resulting cable equations. The capacity for this model to simulate action potentials propagating through branching structures and to predict minimum extracellular stimulation thresholds for individual neurons is demonstrated. The presented model is validated against published values for extracellular stimulation threshold and conduction velocity for realistic physiological parameter values. This model suggests that convoluted axon geometries are more readily activated by extracellular stimulation than linear axon geometries, which may have ramifications for the design of neural prostheses.

  13. Using spectral element method to solve variational inequalities with applications in finance

    International Nuclear Information System (INIS)

    Moradipour, M.; Yousefi, S.A.

    2015-01-01

    Under the Black–Scholes model, the value of an American option solves a time dependent variational inequality problem (VIP). In this paper, first we discretize the variational inequality of American option in temporal direction by applying the Rannacher time stepping and achieve a sequence of elliptic variational inequalities. Second we discretize the spatial domain of variational inequalities by using spectral element methods with high order Lagrangian polynomials introduced on Gauss–Legendre–Lobatto points. Also by computing integrals by the Gauss–Legendre–Lobatto quadrature rule we derive a sequence of the linear complementarity problems (LCPs) having a positive definite sparse coefficient matrix. To find the unique solutions of the LCPs, we use the projected successive over-relaxation (PSOR) algorithm. Furthermore we present some existence and uniqueness theorems for the variational inequalities and LCPs. Finally, theoretical results are verified on the relevant numerical examples.

  14. Direct numerical simulation of the Rayleigh-Taylor instability with the spectral element method

    International Nuclear Information System (INIS)

    Zhang Xu; Tan Duowang

    2009-01-01

    A novel method is proposed to simulate Rayleigh-Taylor instabilities using a specially-developed unsteady three-dimensional high-order spectral element method code. The numerical model used consists of Navier-Stokes equations and a transport-diffusive equation. The code is first validated with the results of linear stability perturbation theory. Then several characteristics of the Rayleigh-Taylor instabilities are studied using this three-dimensional unsteady code, including instantaneous turbulent structures and statistical turbulent mixing heights under different initial wave numbers. These results indicate that turbulent structures of Rayleigh-Taylor instabilities are strongly dependent on the initial conditions. The results also suggest that a high-order numerical method should provide the capability of simulating small scale fluctuations of Rayleigh-Taylor instabilities of turbulent flows. (authors)

  15. Ultrasonic wave propagation in viscoelastic cortical bone plate coupled with fluids: a spectral finite element study.

    Science.gov (United States)

    Nguyen, Vu-Hieu; Naili, Salah

    2013-01-01

    This work deals with the ultrasonic wave propagation in the cortical layer of long bones which is known as being a functionally graded anisotropic material coupled with fluids. The viscous effects are taken into account. The geometrical configuration mimics the one of axial transmission technique used for evaluating the bone quality. We present a numerical procedure adapted for this purpose which is based on the spectral finite element method (FEM). By using a combined Laplace-Fourier transform, the vibroacoustic problem may be transformed into the frequency-wavenumber domain in which, as radiation conditions may be exactly introduced in the infinite fluid halfspaces, only the heterogeneous solid layer needs to be analysed using FEM. Several numerical tests are presented showing very good performance of the proposed approach. We present some results to study the influence of the frequency on the first arriving signal velocity in (visco)elastic bone plate.

  16. Direct Numerical Simulation of the Rayleigh−Taylor Instability with the Spectral Element Method

    International Nuclear Information System (INIS)

    Xu, Zhang; Duo-Wang, Tan

    2009-01-01

    A novel method is proposed to simulate Rayleigh−Taylor instabilities using a specially-developed unsteady three-dimensional high-order spectral element method code. The numerical model used consists of Navier–Stokes equations and a transport-diffusive equation. The code is first validated with the results of linear stability perturbation theory. Then several characteristics of the Rayleigh−Taylor instabilities are studied using this three-dimensional unsteady code, including instantaneous turbulent structures and statistical turbulent mixing heights under different initial wave numbers. These results indicate that turbulent structures of Rayleigh–Taylor instabilities are strongly dependent on the initial conditions. The results also suggest that a high-order numerical method should provide the capability of simulating small scale fluctuations of Rayleigh−Taylor instabilities of turbulent flows. (fundamental areas of phenomenology (including applications))

  17. Spectral Elements Analysis for Viscoelastic Fluids at High Weissenberg Number Using Logarithmic conformation Tensor Model

    Science.gov (United States)

    Jafari, Azadeh; Deville, Michel O.; Fiétier, Nicolas

    2008-09-01

    This study discusses the capability of the constitutive laws for the matrix logarithm of the conformation tensor (LCT model) within the framework of the spectral elements method. The high Weissenberg number problems (HWNP) usually produce a lack of convergence of the numerical algorithms. Even though the question whether the HWNP is a purely numerical problem or rather a breakdown of the constitutive law of the model has remained somewhat of a mystery, it has been recognized that the selection of an appropriate constitutive equation constitutes a very crucial step although implementing a suitable numerical technique is still important for successful discrete modeling of non-Newtonian flows. The LCT model formulation of the viscoelastic equations originally suggested by Fattal and Kupferman is applied for 2-dimensional (2D) FENE-CR model. The Planar Poiseuille flow is considered as a benchmark problem to test this representation at high Weissenberg number. The numerical results are compared with numerical solution of the standard constitutive equation.

  18. Development of a Three-Dimensional Spectral Element Model for NWP: Idealized Simulations on the Sphere

    Science.gov (United States)

    Viner, K.; Reinecke, P. A.; Gabersek, S.; Flagg, D. D.; Doyle, J. D.; Martini, M.; Ryglicki, D.; Michalakes, J.; Giraldo, F.

    2016-12-01

    NEPTUNE: the Navy Environmental Prediction sysTem Using the NUMA*corE, is a 3D spectral element atmospheric model composed of a full suite of physics parameterizations and pre- and post-processing infrastructure with plans for data assimilation and coupling components to a variety of Earth-system models. This talk will focus on the initial struggles and solutions in adapting NUMA for stable and accurate integration on the sphere using both the deep atmosphere equations and a newly developed shallow-atmosphere approximation, as demonstrated through idealized test cases. In addition, details of the physics-dynamics coupling methodology will be discussed. NEPTUNE results for test cases from the 2016 Dynamical Core Model Intercomparison Project (DCMIP-2016) will be shown and discussed. *NUMA: Nonhydrostatic Unified Model of the Atmosphere; Kelly and Giraldo 2012, JCP

  19. Spectral finite element method wave propagation, diagnostics and control in anisotropic and inhomogeneous structures

    CERN Document Server

    Gopalakrishnan, Srinivasan; Roy Mahapatra, Debiprosad

    2008-01-01

    The use of composites and Functionally Graded Materials (FGMs) in structural applications has increased. FGMs allow the user to design materials for a specified functionality and have many uses in structural engineering. However, the behaviour of these structures under high-impact loading is not well understood. This book is the first to apply the Spectral Finite Element Method (SFEM) to inhomogeneous and anisotropic structures in a unified and systematic manner. It focuses on some of the problems with this media which were previously thought unmanageable. Types of SFEM for regular and damaged 1-D and 2-D waveguides, solution techniques, methods of detecting the presence of damages and their locations, and methods for controlling the wave propagation responses are discussed. Tables, figures and graphs support the theory and case studies are included. This book is of value to senior undergraduates and postgraduates studying in this field, and researchers and practicing engineers in structural integrity.

  20. 3D airborne EM modeling based on the spectral-element time-domain (SETD) method

    Science.gov (United States)

    Cao, X.; Yin, C.; Huang, X.; Liu, Y.; Zhang, B., Sr.; Cai, J.; Liu, L.

    2017-12-01

    In the field of 3D airborne electromagnetic (AEM) modeling, both finite-difference time-domain (FDTD) method and finite-element time-domain (FETD) method have limitations that FDTD method depends too much on the grids and time steps, while FETD requires large number of grids for complex structures. We propose a time-domain spectral-element (SETD) method based on GLL interpolation basis functions for spatial discretization and Backward Euler (BE) technique for time discretization. The spectral-element method is based on a weighted residual technique with polynomials as vector basis functions. It can contribute to an accurate result by increasing the order of polynomials and suppressing spurious solution. BE method is a stable tine discretization technique that has no limitation on time steps and can guarantee a higher accuracy during the iteration process. To minimize the non-zero number of sparse matrix and obtain a diagonal mass matrix, we apply the reduced order integral technique. A direct solver with its speed independent of the condition number is adopted for quickly solving the large-scale sparse linear equations system. To check the accuracy of our SETD algorithm, we compare our results with semi-analytical solutions for a three-layered earth model within the time lapse 10-6-10-2s for different physical meshes and SE orders. The results show that the relative errors for magnetic field B and magnetic induction are both around 3-5%. Further we calculate AEM responses for an AEM system over a 3D earth model in Figure 1. From numerical experiments for both 1D and 3D model, we draw the conclusions that: 1) SETD can deliver an accurate results for both dB/dt and B; 2) increasing SE order improves the modeling accuracy for early to middle time channels when the EM field diffuses fast so the high-order SE can model the detailed variation; 3) at very late time channels, increasing SE order has little improvement on modeling accuracy, but the time interval plays

  1. Spectral finite element methods for solving fractional differential equations with applications in anomalous transport

    Energy Technology Data Exchange (ETDEWEB)

    Carella, Alfredo Raul

    2012-09-15

    Quantifying species transport rates is a main concern in chemical and petrochemical industries. In particular, the design and operation of many large-scale industrial chemical processes is as much dependent on diffusion as it is on reaction rates. However, the existing diffusion models sometimes fail to predict experimentally observed behaviors and their accuracy is usually insufficient for process optimization purposes. Fractional diffusion models offer multiple possibilities for generalizing Flick's law in a consistent manner in order to account for history dependence and nonlocal effects. These models have not been extensively applied to the study of real systems, mainly due to their computational cost and mathematical complexity. A least squares spectral formulation was developed for solving fractional differential equations. The proposed method was proven particularly well-suited for dealing with the numerical difficulties inherent to fractional differential operators. The practical implementation was explained in detail in order to enhance reproducibility, and directions were specified for extending it to multiple dimensions and arbitrarily shaped domains. A numerical framework based on the least-squares spectral element method was developed for studying and comparing anomalous diffusion models in pellets. This simulation tool is capable of solving arbitrary integro-differential equations and can be effortlessly adapted to various problems in any number of dimensions. Simulations of the flow around a cylindrical particle were achieved by extending the functionality of the developed framework. A test case was analyzed by coupling the boundary condition yielded by the fluid model with two families of anomalous diffusion models: hyperbolic diffusion and fractional diffusion. Qualitative guidelines for determining the suitability of diffusion models can be formulated by complementing experimental data with the results obtained from this approach.(Author)

  2. Seismoelectric Effects based on Spectral-Element Method for Subsurface Fluid Characterization

    Science.gov (United States)

    Morency, C.

    2017-12-01

    Present approaches for subsurface imaging rely predominantly on seismic techniques, which alone do not capture fluid properties and related mechanisms. On the other hand, electromagnetic (EM) measurements add constraints on the fluid phase through electrical conductivity and permeability, but EM signals alone do not offer information of the solid structural properties. In the recent years, there have been many efforts to combine both seismic and EM data for exploration geophysics. The most popular approach is based on joint inversion of seismic and EM data, as decoupled phenomena, missing out the coupled nature of seismic and EM phenomena such as seismoeletric effects. Seismoelectric effects are related to pore fluid movements with respect to the solid grains. By analyzing coupled poroelastic seismic and EM signals, one can capture a pore scale behavior and access both structural and fluid properties.Here, we model the seismoelectric response by solving the governing equations derived by Pride and Garambois (1994), which correspond to Biot's poroelastic wave equations and Maxwell's electromagnetic wave equations coupled electrokinetically. We will show that these coupled wave equations can be numerically implemented by taking advantage of viscoelastic-electromagnetic mathematical equivalences. These equations will be solved using a spectral-element method (SEM). The SEM, in contrast to finite-element methods (FEM) uses high degree Lagrange polynomials. Not only does this allow the technique to handle complex geometries similarly to FEM, but it also retains exponential convergence and accuracy due to the use of high degree polynomials. Finally, we will discuss how this is a first step toward full coupled seismic-EM inversion to improve subsurface fluid characterization. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  3. A study of flow patterns for staggered cylinders at low Reynolds number by spectral element method

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Li-Chieh; Chen, Chien-Lin; Ye, Jian-Zhi [National Yunlin University of Science and Technology, Taiwan (China)

    2017-06-15

    This study investigates the pattern of flow past two staggered array cylinders using the spectral element method by varying the distance between the cylinders and the angle of incidence (α) at low Reynolds numbers (Re = 100-800). Six flow patterns are identified as Shear layer reattachment (SLR), Induced separation (IS), Vortex impingement (VI), Synchronized vortex shedding (SVS), Vortex pairing and enveloping (VPE), and Vortex pairing splitting and enveloping (VPSE). These flow patterns can be transformed from one to another by changing the distance between the cylinders, the angle of incidence, or Re. SLR, IS and VI flow patterns appear in regimes with small angles of incidence (i.e., α ≤ 30° ) and hold only a single von Karman vortex shedding in a wake with one shedding frequency. SVS, VPE and VPSE flow patterns appear in regimes with large angles of incidence (i.e., 30° ≤ α ≤ 50° ) and present two synchronized von Karman vortices. Quantitative analyses and physical interpretation are also conducted to determine the generation mechanisms of the said flow patterns.

  4. Spatially adaptive hp refinement approach for PN neutron transport equation using spectral element method

    International Nuclear Information System (INIS)

    Nahavandi, N.; Minuchehr, A.; Zolfaghari, A.; Abbasi, M.

    2015-01-01

    Highlights: • Powerful hp-SEM refinement approach for P N neutron transport equation has been presented. • The method provides great geometrical flexibility and lower computational cost. • There is a capability of using arbitrary high order and non uniform meshes. • Both posteriori and priori local error estimation approaches have been employed. • High accurate results are compared against other common adaptive and uniform grids. - Abstract: In this work we presented the adaptive hp-SEM approach which is obtained from the incorporation of Spectral Element Method (SEM) and adaptive hp refinement. The SEM nodal discretization and hp adaptive grid-refinement for even-parity Boltzmann neutron transport equation creates powerful grid refinement approach with high accuracy solutions. In this regard a computer code has been developed to solve multi-group neutron transport equation in one-dimensional geometry using even-parity transport theory. The spatial dependence of flux has been developed via SEM method with Lobatto orthogonal polynomial. Two commonly error estimation approaches, the posteriori and the priori has been implemented. The incorporation of SEM nodal discretization method and adaptive hp grid refinement leads to high accurate solutions. Coarser meshes efficiency and significant reduction of computer program runtime in comparison with other common refining methods and uniform meshing approaches is tested along several well-known transport benchmarks

  5. Near-fault earthquake ground motion prediction by a high-performance spectral element numerical code

    International Nuclear Information System (INIS)

    Paolucci, Roberto; Stupazzini, Marco

    2008-01-01

    Near-fault effects have been widely recognised to produce specific features of earthquake ground motion, that cannot be reliably predicted by 1D seismic wave propagation modelling, used as a standard in engineering applications. These features may have a relevant impact on the structural response, especially in the nonlinear range, that is hard to predict and to be put in a design format, due to the scarcity of significant earthquake records and of reliable numerical simulations. In this contribution a pilot study is presented for the evaluation of seismic ground-motions in the near-fault region, based on a high-performance numerical code for 3D seismic wave propagation analyses, including the seismic fault, the wave propagation path and the near-surface geological or topographical irregularity. For this purpose, the software package GeoELSE is adopted, based on the spectral element method. The set-up of the numerical benchmark of 3D ground motion simulation in the valley of Grenoble (French Alps) is chosen to study the effect of the complex interaction between basin geometry and radiation mechanism on the variability of earthquake ground motion

  6. Rendering the Topological Spines

    Energy Technology Data Exchange (ETDEWEB)

    Nieves-Rivera, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-05-05

    Many tools to analyze and represent high dimensional data already exits yet most of them are not flexible, informative and intuitive enough to help the scientists make the corresponding analysis and predictions, understand the structure and complexity of scientific data, get a complete picture of it and explore a greater number of hypotheses. With this in mind, N-Dimensional Data Analysis and Visualization (ND²AV) is being developed to serve as an interactive visual analysis platform with the purpose of coupling together a number of these existing tools that range from statistics, machine learning, and data mining, with new techniques, in particular with new visualization approaches. My task is to create the rendering and implementation of a new concept called topological spines in order to extend ND²AV's scope. Other existing visualization tools create a representation preserving either the topological properties or the structural (geometric) ones because it is challenging to preserve them both simultaneously. Overcoming such challenge by creating a balance in between them, the topological spines are introduced as a new approach that aims to preserve them both. Its render using OpenGL and C++ and is currently being tested to further on be implemented on ND²AV. In this paper I will present what are the Topological Spines and how they are rendered.

  7. Spectral-element Seismic Wave Propagation on CUDA/OpenCL Hardware Accelerators

    Science.gov (United States)

    Peter, D. B.; Videau, B.; Pouget, K.; Komatitsch, D.

    2015-12-01

    Seismic wave propagation codes are essential tools to investigate a variety of wave phenomena in the Earth. Furthermore, they can now be used for seismic full-waveform inversions in regional- and global-scale adjoint tomography. Although these seismic wave propagation solvers are crucial ingredients to improve the resolution of tomographic images to answer important questions about the nature of Earth's internal processes and subsurface structure, their practical application is often limited due to high computational costs. They thus need high-performance computing (HPC) facilities to improving the current state of knowledge. At present, numerous large HPC systems embed many-core architectures such as graphics processing units (GPUs) to enhance numerical performance. Such hardware accelerators can be programmed using either the CUDA programming environment or the OpenCL language standard. CUDA software development targets NVIDIA graphic cards while OpenCL was adopted by additional hardware accelerators, like e.g. AMD graphic cards, ARM-based processors as well as Intel Xeon Phi coprocessors. For seismic wave propagation simulations using the open-source spectral-element code package SPECFEM3D_GLOBE, we incorporated an automatic source-to-source code generation tool (BOAST) which allows us to use meta-programming of all computational kernels for forward and adjoint runs. Using our BOAST kernels, we generate optimized source code for both CUDA and OpenCL languages within the source code package. Thus, seismic wave simulations are able now to fully utilize CUDA and OpenCL hardware accelerators. We show benchmarks of forward seismic wave propagation simulations using SPECFEM3D_GLOBE on CUDA/OpenCL GPUs, validating results and comparing performances for different simulations and hardware usages.

  8. Forward and adjoint spectral-element simulations of seismic wave propagation using hardware accelerators

    Science.gov (United States)

    Peter, Daniel; Videau, Brice; Pouget, Kevin; Komatitsch, Dimitri

    2015-04-01

    Improving the resolution of tomographic images is crucial to answer important questions on the nature of Earth's subsurface structure and internal processes. Seismic tomography is the most prominent approach where seismic signals from ground-motion records are used to infer physical properties of internal structures such as compressional- and shear-wave speeds, anisotropy and attenuation. Recent advances in regional- and global-scale seismic inversions move towards full-waveform inversions which require accurate simulations of seismic wave propagation in complex 3D media, providing access to the full 3D seismic wavefields. However, these numerical simulations are computationally very expensive and need high-performance computing (HPC) facilities for further improving the current state of knowledge. During recent years, many-core architectures such as graphics processing units (GPUs) have been added to available large HPC systems. Such GPU-accelerated computing together with advances in multi-core central processing units (CPUs) can greatly accelerate scientific applications. There are mainly two possible choices of language support for GPU cards, the CUDA programming environment and OpenCL language standard. CUDA software development targets NVIDIA graphic cards while OpenCL was adopted mainly by AMD graphic cards. In order to employ such hardware accelerators for seismic wave propagation simulations, we incorporated a code generation tool BOAST into an existing spectral-element code package SPECFEM3D_GLOBE. This allows us to use meta-programming of computational kernels and generate optimized source code for both CUDA and OpenCL languages, running simulations on either CUDA or OpenCL hardware accelerators. We show here applications of forward and adjoint seismic wave propagation on CUDA/OpenCL GPUs, validating results and comparing performances for different simulations and hardware usages.

  9. High Fidelity Haptic Rendering

    CERN Document Server

    Otaduy, Miguel A

    2006-01-01

    The human haptic system, among all senses, provides unique and bidirectional communication between humans and their physical environment. Yet, to date, most human-computer interactive systems have focused primarily on the graphical rendering of visual information and, to a lesser extent, on the display of auditory information. Extending the frontier of visual computing, haptic interfaces, or force feedback devices, have the potential to increase the quality of human-computer interaction by accommodating the sense of touch. They provide an attractive augmentation to visual display and enhance t

  10. Multilayer photosensitive structures based on porous silicon and rare-earth-element compounds: Study of spectral characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kirsanov, N. Yu.; Latukhina, N. V., E-mail: natalat@yandex.ru; Lizunkova, D. A.; Rogozhina, G. A. [Samara National Research University (Russian Federation); Stepikhova, M. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    2017-03-15

    The spectral characteristics of the specular reflectance, photosensitivity, and photoluminescence (PL) of multilayer structures based on porous silicon with rare-earth-element (REE) ions are investigated. It is shown that the photosensitivity of these structures in the wavelength range of 0.4–1.0 μm is higher than in structures free of REEs. The structures with Er{sup 3+} ions exhibit a luminescence response at room temperature in the spectral range from 1.1 to 1.7 μm. The PL spectrum of the erbium impurity is characterized by a fine line structure, which is determined by the splitting of the {sup 4}I{sub 15/2} multiplet of the Er{sup 3+} ion. It is shown that the structures with a porous layer on the working surface have a much lower reflectance in the entire spectral range under study (0.2–1.0 μm).

  11. Local and Global Illumination in the Volume Rendering Integral

    Energy Technology Data Exchange (ETDEWEB)

    Max, N; Chen, M

    2005-10-21

    This article is intended as an update of the major survey by Max [1] on optical models for direct volume rendering. It provides a brief overview of the subject scope covered by [1], and brings recent developments, such as new shadow algorithms and refraction rendering, into the perspective. In particular, we examine three fundamentals aspects of direct volume rendering, namely the volume rendering integral, local illumination models and global illumination models, in a wavelength-independent manner. We review the developments on spectral volume rendering, in which visible light are considered as a form of electromagnetic radiation, optical models are implemented in conjunction with representations of spectral power distribution. This survey can provide a basis for, and encourage, new efforts for developing and using complex illumination models to achieve better realism and perception through optical correctness.

  12. A New High-Order Spectral Difference Method for Simulating Viscous Flows on Unstructured Grids with Mixed Elements

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mao; Qiu, Zihua; Liang, Chunlei; Sprague, Michael; Xu, Min

    2017-01-13

    In the present study, a new spectral difference (SD) method is developed for viscous flows on meshes with a mixture of triangular and quadrilateral elements. The standard SD method for triangular elements, which employs Lagrangian interpolating functions for fluxes, is not stable when the designed accuracy of spatial discretization is third-order or higher. Unlike the standard SD method, the method examined here uses vector interpolating functions in the Raviart-Thomas (RT) spaces to construct continuous flux functions on reference elements. Studies have been performed for 2D wave equation and Euler equa- tions. Our present results demonstrated that the SDRT method is stable and high-order accurate for a number of test problems by using triangular-, quadrilateral-, and mixed- element meshes.

  13. A fully-coupled discontinuous Galerkin spectral element method for two-phase flow in petroleum reservoirs

    Science.gov (United States)

    Taneja, Ankur; Higdon, Jonathan

    2018-01-01

    A high-order spectral element discontinuous Galerkin method is presented for simulating immiscible two-phase flow in petroleum reservoirs. The governing equations involve a coupled system of strongly nonlinear partial differential equations for the pressure and fluid saturation in the reservoir. A fully implicit method is used with a high-order accurate time integration using an implicit Rosenbrock method. Numerical tests give the first demonstration of high order hp spatial convergence results for multiphase flow in petroleum reservoirs with industry standard relative permeability models. High order convergence is shown formally for spectral elements with up to 8th order polynomials for both homogeneous and heterogeneous permeability fields. Numerical results are presented for multiphase fluid flow in heterogeneous reservoirs with complex geometric or geologic features using up to 11th order polynomials. Robust, stable simulations are presented for heterogeneous geologic features, including globally heterogeneous permeability fields, anisotropic permeability tensors, broad regions of low-permeability, high-permeability channels, thin shale barriers and thin high-permeability fractures. A major result of this paper is the demonstration that the resolution of the high order spectral element method may be exploited to achieve accurate results utilizing a simple cartesian mesh for non-conforming geological features. Eliminating the need to mesh to the boundaries of geological features greatly simplifies the workflow for petroleum engineers testing multiple scenarios in the face of uncertainty in the subsurface geology.

  14. Inferring global upper-mantle shear attenuation structure by waveform tomography using the spectral element method

    Science.gov (United States)

    Karaoǧlu, Haydar; Romanowicz, Barbara

    2018-06-01

    We present a global upper-mantle shear wave attenuation model that is built through a hybrid full-waveform inversion algorithm applied to long-period waveforms, using the spectral element method for wavefield computations. Our inversion strategy is based on an iterative approach that involves the inversion for successive updates in the attenuation parameter (δ Q^{-1}_μ) and elastic parameters (isotropic velocity VS, and radial anisotropy parameter ξ) through a Gauss-Newton-type optimization scheme that employs envelope- and waveform-type misfit functionals for the two steps, respectively. We also include source and receiver terms in the inversion steps for attenuation structure. We conducted a total of eight iterations (six for attenuation and two for elastic structure), and one inversion for updates to source parameters. The starting model included the elastic part of the relatively high-resolution 3-D whole mantle seismic velocity model, SEMUCB-WM1, which served to account for elastic focusing effects. The data set is a subset of the three-component surface waveform data set, filtered between 400 and 60 s, that contributed to the construction of the whole-mantle tomographic model SEMUCB-WM1. We applied strict selection criteria to this data set for the attenuation iteration steps, and investigated the effect of attenuation crustal structure on the retrieved mantle attenuation structure. While a constant 1-D Qμ model with a constant value of 165 throughout the upper mantle was used as starting model for attenuation inversion, we were able to recover, in depth extent and strength, the high-attenuation zone present in the depth range 80-200 km. The final 3-D model, SEMUCB-UMQ, shows strong correlation with tectonic features down to 200-250 km depth, with low attenuation beneath the cratons, stable parts of continents and regions of old oceanic crust, and high attenuation along mid-ocean ridges and backarcs. Below 250 km, we observe strong attenuation in the

  15. ARE: Ada Rendering Engine

    Directory of Open Access Journals (Sweden)

    Stefano Penge

    2009-10-01

    Full Text Available E' ormai pratica diffusa, nello sviluppo di applicazioni web, l'utilizzo di template e di potenti template engine per automatizzare la generazione dei contenuti da presentare all'utente. Tuttavia a volte la potenza di tali engine è€ ottenuta mescolando logica e interfaccia, introducendo linguaggi diversi da quelli di descrizione della pagina, o addirittura inventando nuovi linguaggi dedicati.ARE (ADA Rendering Engine è€ pensato per gestire l'intero flusso di creazione del contenuto HTML/XHTML dinamico, la selezione del corretto template, CSS, JavaScript e la produzione dell'output separando completamente logica e interfaccia. I templates utilizzati sono puro HTML senza parti in altri linguaggi, e possono quindi essere gestiti e visualizzati autonomamente. Il codice HTML generato è€ uniforme e parametrizzato.E' composto da due moduli, CORE (Common Output Rendering Engine e ALE (ADA Layout Engine.Il primo (CORE viene utilizzato per la generazione OO degli elementi del DOM ed è pensato per aiutare lo sviluppatore nella produzione di codice valido rispetto al DTD utilizzato. CORE genera automaticamente gli elementi del DOM in base al DTD impostato nella configurazioneIl secondo (ALE viene utilizzato come template engine per selezionare automaticamente in base ad alcuni parametri (modulo, profilo utente, tipologia del nodo, del corso, preferenze di installazione il template HTML, i CSS e i file JavaScript appropriati. ALE permette di usare templates di default e microtemplates ricorsivi per semplificare il lavoro del grafico.I due moduli possono in ogni caso essere utilizzati indipendentemente l'uno dall'altro. E' possibile generare e renderizzare una pagina HTML utilizzando solo CORE oppure inviare gli oggetti CORE al template engine ALE che provvede a renderizzare la pagina HTML. Viceversa è possibile generare HTML senza utilizzare CORE ed inviarlo al template engine ALECORE è alla prima release ed è€ già utilizzato all

  16. Analysis of X-ray Spectra of High-Z Elements obtained on Nike with high spectral and spatial resolution

    Science.gov (United States)

    Aglitskiy, Yefim; Weaver, J. L.; Karasik, M.; Serlin, V.; Obenschain, S. P.; Ralchenko, Yu.

    2014-10-01

    The spectra of multi-charged ions of Hf, Ta, W, Pt, Au and Bi have been studied on Nike krypton-fluoride laser facility with the help of two kinds of X-ray spectrometers. First, survey instrument covering a spectral range from 0.5 to 19.5 angstroms which allows simultaneous observation of both M- and N- spectra of above mentioned elements with high spectral resolution. Second, an imaging spectrometer with interchangeable spherically bent Quartz crystals that added higher efficiency, higher spectral resolution and high spatial resolution to the qualities of the former one. Multiple spectral lines with X-ray energies as high as 4 keV that belong to the isoelectronic sequences of Fe, Co, Ni, Cu and Zn were identified with the help of NOMAD package developed by Dr. Yu. Ralchenko and colleagues. In our continuous effort to support DOE-NNSA's inertial fusion program, this campaign covered a wide range of plasma conditions that result in production of relatively energetic X-rays. Work supported by the US DOE/NNSA.

  17. Parallel hierarchical radiosity rendering

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Michael [Iowa State Univ., Ames, IA (United States)

    1993-07-01

    In this dissertation, the step-by-step development of a scalable parallel hierarchical radiosity renderer is documented. First, a new look is taken at the traditional radiosity equation, and a new form is presented in which the matrix of linear system coefficients is transformed into a symmetric matrix, thereby simplifying the problem and enabling a new solution technique to be applied. Next, the state-of-the-art hierarchical radiosity methods are examined for their suitability to parallel implementation, and scalability. Significant enhancements are also discovered which both improve their theoretical foundations and improve the images they generate. The resultant hierarchical radiosity algorithm is then examined for sources of parallelism, and for an architectural mapping. Several architectural mappings are discussed. A few key algorithmic changes are suggested during the process of making the algorithm parallel. Next, the performance, efficiency, and scalability of the algorithm are analyzed. The dissertation closes with a discussion of several ideas which have the potential to further enhance the hierarchical radiosity method, or provide an entirely new forum for the application of hierarchical methods.

  18. Stability Estimates for h-p Spectral Element Methods for Elliptic Problems

    NARCIS (Netherlands)

    Dutt, Pravir; Tomar, S.K.; Kumar, B.V. Rathish

    2002-01-01

    In a series of papers of which this is the first we study how to solve elliptic problems on polygonal domains using spectral methods on parallel computers. To overcome the singularities that arise in a neighborhood of the corners we use a geometrical mesh. With this mesh we seek a solution which

  19. Transformative Rendering of Internet Resources

    Science.gov (United States)

    2012-10-01

    using either the Firefox or Google Chrome rendering engine. The rendering server then captures a screen shot of the page and creates code that positions...be compromised at web pages the hackers had built for that hacking competition to exploit that particular OS /browser configuration. During...of risk with no benefit. They include: - The rendering server is hosted on a Linux-based operating system ( OS ). The OS is much more secure than the

  20. 3D anisotropic modeling and identification for airborne EM systems based on the spectral-element method

    Science.gov (United States)

    Huang, Xin; Yin, Chang-Chun; Cao, Xiao-Yue; Liu, Yun-He; Zhang, Bo; Cai, Jing

    2017-09-01

    The airborne electromagnetic (AEM) method has a high sampling rate and survey flexibility. However, traditional numerical modeling approaches must use high-resolution physical grids to guarantee modeling accuracy, especially for complex geological structures such as anisotropic earth. This can lead to huge computational costs. To solve this problem, we propose a spectral-element (SE) method for 3D AEM anisotropic modeling, which combines the advantages of spectral and finite-element methods. Thus, the SE method has accuracy as high as that of the spectral method and the ability to model complex geology inherited from the finite-element method. The SE method can improve the modeling accuracy within discrete grids and reduce the dependence of modeling results on the grids. This helps achieve high-accuracy anisotropic AEM modeling. We first introduced a rotating tensor of anisotropic conductivity to Maxwell's equations and described the electrical field via SE basis functions based on GLL interpolation polynomials. We used the Galerkin weighted residual method to establish the linear equation system for the SE method, and we took a vertical magnetic dipole as the transmission source for our AEM modeling. We then applied fourth-order SE calculations with coarse physical grids to check the accuracy of our modeling results against a 1D semi-analytical solution for an anisotropic half-space model and verified the high accuracy of the SE. Moreover, we conducted AEM modeling for different anisotropic 3D abnormal bodies using two physical grid scales and three orders of SE to obtain the convergence conditions for different anisotropic abnormal bodies. Finally, we studied the identification of anisotropy for single anisotropic abnormal bodies, anisotropic surrounding rock, and single anisotropic abnormal body embedded in an anisotropic surrounding rock. This approach will play a key role in the inversion and interpretation of AEM data collected in regions with anisotropic

  1. Spectral-element simulation of two-dimensional elastic wave propagation in fully heterogeneous media on a GPU cluster

    Science.gov (United States)

    Rudianto, Indra; Sudarmaji

    2018-04-01

    We present an implementation of the spectral-element method for simulation of two-dimensional elastic wave propagation in fully heterogeneous media. We have incorporated most of realistic geological features in the model, including surface topography, curved layer interfaces, and 2-D wave-speed heterogeneity. To accommodate such complexity, we use an unstructured quadrilateral meshing technique. Simulation was performed on a GPU cluster, which consists of 24 core processors Intel Xeon CPU and 4 NVIDIA Quadro graphics cards using CUDA and MPI implementation. We speed up the computation by a factor of about 5 compared to MPI only, and by a factor of about 40 compared to Serial implementation.

  2. Sketchy Rendering for Information Visualization

    NARCIS (Netherlands)

    Wood, Jo; Isenberg, Petra; Isenberg, Tobias; Dykes, Jason; Boukhelifa, Nadia; Slingsby, Aidan

    2012-01-01

    We present and evaluate a framework for constructing sketchy style information visualizations that mimic data graphics drawn by hand. We provide an alternative renderer for the Processing graphics environment that redefines core drawing primitives including line, polygon and ellipse rendering. These

  3. Simulation of ultrasonic wave propagation in anisotropic poroelastic bone plate using hybrid spectral/finite element method.

    Science.gov (United States)

    Nguyen, Vu-Hieu; Naili, Salah

    2012-08-01

    This paper deals with the modeling of guided waves propagation in in vivo cortical long bone, which is known to be anisotropic medium with functionally graded porosity. The bone is modeled as an anisotropic poroelastic material by using Biot's theory formulated in high frequency domain. A hybrid spectral/finite element formulation has been developed to find the time-domain solution of ultrasonic waves propagating in a poroelastic plate immersed in two fluid halfspaces. The numerical technique is based on a combined Laplace-Fourier transform, which allows to obtain a reduced dimension problem in the frequency-wavenumber domain. In the spectral domain, as radiation conditions representing infinite fluid halfspaces may be exactly introduced, only the heterogeneous solid layer needs to be analyzed by using finite element method. Several numerical tests are presented showing very good performance of the proposed procedure. A preliminary study on the first arrived signal velocities computed by using equivalent elastic and poroelastic models will be presented. Copyright © 2012 John Wiley & Sons, Ltd.

  4. Spectral-Element Seismic Wave Propagation Codes for both Forward Modeling in Complex Media and Adjoint Tomography

    Science.gov (United States)

    Smith, J. A.; Peter, D. B.; Tromp, J.; Komatitsch, D.; Lefebvre, M. P.

    2015-12-01

    We present both SPECFEM3D_Cartesian and SPECFEM3D_GLOBE open-source codes, representing high-performance numerical wave solvers simulating seismic wave propagation for local-, regional-, and global-scale application. These codes are suitable for both forward propagation in complex media and tomographic imaging. Both solvers compute highly accurate seismic wave fields using the continuous Galerkin spectral-element method on unstructured meshes. Lateral variations in compressional- and shear-wave speeds, density, as well as 3D attenuation Q models, topography and fluid-solid coupling are all readily included in both codes. For global simulations, effects due to rotation, ellipticity, the oceans, 3D crustal models, and self-gravitation are additionally included. Both packages provide forward and adjoint functionality suitable for adjoint tomography on high-performance computing architectures. We highlight the most recent release of the global version which includes improved performance, simultaneous MPI runs, OpenCL and CUDA support via an automatic source-to-source transformation library (BOAST), parallel I/O readers and writers for databases using ADIOS and seismograms using the recently developed Adaptable Seismic Data Format (ASDF) with built-in provenance. This makes our spectral-element solvers current state-of-the-art, open-source community codes for high-performance seismic wave propagation on arbitrarily complex 3D models. Together with these solvers, we provide full-waveform inversion tools to image the Earth's interior at unprecedented resolution.

  5. Magnetic modeling of a Linear Synchronous Machine with the spectral element method

    NARCIS (Netherlands)

    Curti, M.; Paulides, J.J.H.; Lomonova, E.

    2017-01-01

    The field calculus for electrical machines is realized solving subdomain problems. Most often, the latter are solved using either finite element analysis or the semi-analytical solution of a Laplace or Poisson equation obtained by separation of variables. The first option can capture complex

  6. Magnetic modeling of a Linear Synchronous Machine with the spectral element method

    NARCIS (Netherlands)

    Curti, M.; Paulides, J.J.H.; Lomonova, E.

    2017-01-01

    The field calculus for electrical machines (EMs) is realized solving subdomain problems. Most often, the latter are solved using either finite element analysis (FEA) or the semi-analytical solution of a Laplace or Poisson equation obtained by separation of variables. The first option can capture

  7. Space-time coupled spectral/hp least-squares finite element formulation for the incompressible Navier-Stokes equations

    International Nuclear Information System (INIS)

    Pontaza, J.P.; Reddy, J.N.

    2004-01-01

    We consider least-squares finite element models for the numerical solution of the non-stationary Navier-Stokes equations governing viscous incompressible fluid flows. The paper presents a formulation where the effects of space and time are coupled, resulting in a true space-time least-squares minimization procedure, as opposed to a space-time decoupled formulation where a least-squares minimization procedure is performed in space at each time step. The formulation is first presented for the linear advection-diffusion equation and then extended to the Navier-Stokes equations. The formulation has no time step stability restrictions and is spectrally accurate in both space and time. To allow the use of practical C 0 element expansions in the resulting finite element model, the Navier-Stokes equations are expressed as an equivalent set of first-order equations by introducing vorticity as an additional independent variable and the least-squares method is used to develop the finite element model of the governing equations. High-order element expansions are used to construct the discrete model. The discrete model thus obtained is linearized by Newton's method, resulting in a linear system of equations with a symmetric positive definite coefficient matrix that is solved in a fully coupled manner by a preconditioned conjugate gradient method in matrix-free form. Spectral convergence of the L 2 least-squares functional and L 2 error norms in space-time is verified using a smooth solution to the two-dimensional non-stationary incompressible Navier-Stokes equations. Numerical results are presented for impulsively started lid-driven cavity flow, oscillatory lid-driven cavity flow, transient flow over a backward-facing step, and flow around a circular cylinder; the results demonstrate the predictive capability and robustness of the proposed formulation. Even though the space-time coupled formulation is emphasized, we also present the formulation and numerical results for least

  8. Conjugation of fiber-coupled wide-band light sources and acousto-optical spectral elements

    Science.gov (United States)

    Machikhin, Alexander; Batshev, Vladislav; Polschikova, Olga; Khokhlov, Demid; Pozhar, Vitold; Gorevoy, Alexey

    2017-12-01

    Endoscopic instrumentation is widely used for diagnostics and surgery. The imaging systems, which provide the hyperspectral information of the tissues accessible by endoscopes, are particularly interesting and promising for in vivo photoluminescence diagnostics and therapy of tumour and inflammatory diseases. To add the spectral imaging feature to standard video endoscopes, we propose to implement acousto-optical (AO) filtration of wide-band illumination of incandescent-lamp-based light sources. To collect maximum light and direct it to the fiber-optic light guide inside the endoscopic probe, we have developed and tested the optical system for coupling the light source, the acousto-optical tunable filter (AOTF) and the light guide. The system is compact and compatible with the standard endoscopic components.

  9. Spectral and thermal behaviours of rare earth element complexes with 3,5-dimethoxybenzoic acid

    Directory of Open Access Journals (Sweden)

    JANUSZ CHRUŚCIEL

    2003-10-01

    Full Text Available The conditions for the formation of rare earth element 3,5-dimethytoxybenzoates were studied and their quantitative composition and solubilities in water at 293 K were determined. The complexes are anhydrous or hydrated salts and their solubilities are of the orders of 10-5 – 10-4 mol dm-3. Their FTIR, FIR and X-ray spectra were recorded. The compounds were also characterized by thermogravimetric studies in air and nitrogen atmospheres and by magnetic measurements. All complexes are crystalline compounds. The carboxylate group in these complexes is a bidentate, chelating ligand. On heating in air to 1173 K, the 3,5-dimethoxybenzoates of rare earth elements decompose in various ways. The hydrated complexes first dehydrate to form anhydrous salts which then decompose in air to the oxides of the respective metals while in nitrogen to mixtures of carbon and oxides of the respective metals. The complexes are more stable in air than in nitrogen.

  10. Spectral element modelling of wave propagation in isotropic and anisotropic shell-structures including different types of damage

    International Nuclear Information System (INIS)

    Schulte, R T; Fritzen, C-P; Moll, J

    2010-01-01

    During the last decades, guided waves have shown great potential for Structural Health Monitoring (SHM) applications. These waves can be excited and sensed by piezoelectric elements that can be permanently attached onto a structure offering online monitoring capability. However, the setup of wave based SHM systems for complex structures may be very difficult and time consuming. For that reason there is a growing demand for efficient simulation tools providing the opportunity to design wave based SHM systems in a virtual environment. As usually high frequency waves are used, the associated short wavelength leads to the necessity of a very dense mesh, which makes conventional finite elements not well suited for this purpose. Therefore in this contribution a flat shell spectral element approach is presented. By including electromechanical coupling a SHM system can be simulated entirely from actuator voltage to sensor voltage. Besides a comparison to measured data for anisotropic materials including delamination, a numerical example of a more complex, stiffened shell structure with debonding is presented.

  11. Modeling of the Through-the-Thickness Electric Potentials of a Piezoelectric Bimorph Using the Spectral Element Method

    Directory of Open Access Journals (Sweden)

    Xingjian Dong

    2014-02-01

    Full Text Available An efficient spectral element (SE with electric potential degrees of freedom (DOF is proposed to investigate the static electromechanical responses of a piezoelectric bimorph for its actuator and sensor functions. A sublayer model based on the piecewise linear approximation for the electric potential is used to describe the nonlinear distribution of electric potential through the thickness of the piezoelectric layers. An equivalent single layer (ESL model based on first-order shear deformation theory (FSDT is used to describe the displacement field. The Legendre orthogonal polynomials of order 5 are used in the element interpolation functions. The validity and the capability of the present SE model for investigation of global and local responses of the piezoelectric bimorph are confirmed by comparing the present solutions with those obtained from coupled 3-D finite element (FE analysis. It is shown that, without introducing any higher-order electric potential assumptions, the current method can accurately describe the distribution of the electric potential across the thickness even for a rather thick bimorph. It is revealed that the effect of electric potential is significant when the bimorph is used as sensor while the effect is insignificant when the bimorph is used as actuator, and therefore, the present study may provide a better understanding of the nonlinear induced electric potential for bimorph sensor and actuator.

  12. Quasistatic field simulations based on finite elements and spectral methods applied to superconducting magnets

    International Nuclear Information System (INIS)

    Koch, Stephan

    2009-01-01

    This thesis is concerned with the numerical simulation of electromagnetic fields in the quasi-static approximation which is applicable in many practical cases. Main emphasis is put on higher-order finite element methods. Quasi-static applications can be found, e.g., in accelerator physics in terms of the design of magnets required for beam guidance, in power engineering as well as in high-voltage engineering. Especially during the first design and optimization phase of respective devices, numerical models offer a cheap alternative to the often costly assembly of prototypes. However, large differences in the magnitude of the material parameters and the geometric dimensions as well as in the time-scales of the electromagnetic phenomena involved lead to an unacceptably long simulation time or to an inadequately large memory requirement. Under certain circumstances, the simulation itself and, in turn, the desired design improvement becomes even impossible. In the context of this thesis, two strategies aiming at the extension of the range of application for numerical simulations based on the finite element method are pursued. The first strategy consists in parallelizing existing methods such that the computation can be distributed over several computers or cores of a processor. As a consequence, it becomes feasible to simulate a larger range of devices featuring more degrees of freedom in the numerical model than before. This is illustrated for the calculation of the electromagnetic fields, in particular of the eddy-current losses, inside a superconducting dipole magnet developed at the GSI Helmholtzzentrum fuer Schwerionenforschung as a part of the FAIR project. As the second strategy to improve the efficiency of numerical simulations, a hybrid discretization scheme exploiting certain geometrical symmetries is established. Using this method, a significant reduction of the numerical effort in terms of required degrees of freedom for a given accuracy is achieved. The

  13. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madhavi Z [ORNL; Fox, Dr. Richard V [Idaho National Laboratory (INL); Miziolek, Andrzej W [United States Army Research Laboratory; DeLucia, Frank C [United States Army Research Laboratory; Andre, Nicolas O [ORNL

    2015-01-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  14. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madhavi Z [ORNL; Fox, Dr. Richard V [Idaho National Laboratory (INL); Miziolek, Andrzej W [United States Army Research Laboratory; DeLucia, Frank C [United States Army Research Laboratory; Andre, Nicolas O [ORNL

    2015-01-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in real-world complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  15. Simulation of heat and mass transfer in turbulent channel flow using the spectral-element method: effect of spatial resolution

    Science.gov (United States)

    Ryzhenkov, V.; Ivashchenko, V.; Vinuesa, R.; Mullyadzhanov, R.

    2016-10-01

    We use the open-source code nek5000 to assess the accuracy of high-order spectral element large-eddy simulations (LES) of a turbulent channel flow depending on the spatial resolution compared to the direct numerical simulation (DNS). The Reynolds number Re = 6800 is considered based on the bulk velocity and half-width of the channel. The filtered governing equations are closed with the dynamic Smagorinsky model for subgrid stresses and heat flux. The results show very good agreement between LES and DNS for time-averaged velocity and temperature profiles and their fluctuations. Even the coarse LES grid which contains around 30 times less points than the DNS one provided predictions of the friction velocity within 2.0% accuracy interval.

  16. Conservation of old renderings - the consolidation of rendering with loss of cohesion

    Directory of Open Access Journals (Sweden)

    Martha Tavares

    2008-01-01

    Full Text Available The study of external renderings in the scope of conservation and restoration has acquired in the last years great methodological, scientific and technical advances. These renderings are important elements of the built structure, for besides possessing a protection function, they possess often a decorative function of great relevance for the image of the monument. The maintenance of these renderings implies the conservation of traditional constructive techniques and the use of compatible materials, as similar to the originals as possible. The main objective of this study is to define a methodology of conservative restoration using strategies of maintenance of renderings and traditional constructive techniques. The minimum intervention principle is maintained as well as the use of materials compatible with the original ones. This paper describes the technique and products used for the consolidation of the loss of cohesion. The testing campaign was developed under controlled conditions, in laboratory, and in situ in order to evaluate their efficacy for the consolidation of old renders. A set of tests is presented to evaluate the effectiveness of the process. The results are analysed and a reflection is added referring to the applicability of these techniques. Finally the paper presents a proposal for further research.

  17. Band-gap analysis of a novel lattice with a hierarchical periodicity using the spectral element method

    Science.gov (United States)

    Wu, Zhijing; Li, Fengming; Zhang, Chuanzeng

    2018-05-01

    Inspired by the hierarchical structures of butterfly wing surfaces, a new kind of lattice structures with a two-order hierarchical periodicity is proposed and designed, and the band-gap properties are investigated by the spectral element method (SEM). The equations of motion of the whole structure are established considering the macro and micro periodicities of the system. The efficiency of the SEM is exploited in the modeling process and validated by comparing the results with that of the finite element method (FEM). Based on the highly accurate results in the frequency domain, the dynamic behaviors of the proposed two-order hierarchical structures are analyzed. An original and interesting finding is the existence of the distinct macro and micro stop-bands in the given frequency domain. The mechanisms for these two types of band-gaps are also explored. Finally, the relations between the hierarchical periodicities and the different types of the stop-bands are investigated by analyzing the parametrical influences.

  18. Advanced Material Rendering in Blender

    Czech Academy of Sciences Publication Activity Database

    Hatka, Martin; Haindl, Michal

    2012-01-01

    Roč. 11, č. 2 (2012), s. 15-23 ISSN 1081-1451 R&D Projects: GA ČR GAP103/11/0335; GA ČR GA102/08/0593 Grant - others:CESNET(CZ) 387/2010; CESNET(CZ) 409/2011 Institutional support: RVO:67985556 Keywords : realistic material rendering * bidirectional texture function * Blender Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2013/RO/haindl-advanced material rendering in blender.pdf

  19. Numerical Simulations of Microseisms in a NE Atlantic 3D Geological Model, using a Spectral-Element Method

    Science.gov (United States)

    Ying, Yingzi; Bean, Christopher J.

    2014-05-01

    Ocean-generated microseisms are faint Earth tremors associated with the interaction between ocean water waves and the solid Earth. The microseism noise recorded as low frequency ground vibrations by seismometers contains significant information about the Earth's interior and the sea states. In this work, we first aim to investigate the forward propagation of microseisms in a deep-ocean environment. We employ a 3D North-East Atlantic geological model and simulate wave propagation in a coupled fluid-solid domain, using a spectral-element method. The aim is to investigate the effects of the continental shelf on microseism wave propagation. A second goal of this work is to perform noise simulation to calculate synthetic ensemble averaged cross-correlations of microseism noise signals with time reversal method. The algorithm can relieve computational cost by avoiding time stacking and get cross-correlations between the designated master station and all the remaining slave stations, at one time. The origins of microseisms are non-uniform, so we also test the effect of simulated noise source distribution on the determined cross-correlations.

  20. A Hybrid Finite Element-Fourier Spectral Method for Vibration Analysis of Structures with Elastic Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Wan-You Li

    2014-01-01

    Full Text Available A novel hybrid method, which simultaneously possesses the efficiency of Fourier spectral method (FSM and the applicability of the finite element method (FEM, is presented for the vibration analysis of structures with elastic boundary conditions. The FSM, as one type of analytical approaches with excellent convergence and accuracy, is mainly limited to problems with relatively regular geometry. The purpose of the current study is to extend the FSM to problems with irregular geometry via the FEM and attempt to take full advantage of the FSM and the conventional FEM for structural vibration problems. The computational domain of general shape is divided into several subdomains firstly, some of which are represented by the FSM while the rest by the FEM. Then, fictitious springs are introduced for connecting these subdomains. Sufficient details are given to describe the development of such a hybrid method. Numerical examples of a one-dimensional Euler-Bernoulli beam and a two-dimensional rectangular plate show that the present method has good accuracy and efficiency. Further, one irregular-shaped plate which consists of one rectangular plate and one semi-circular plate also demonstrates the capability of the present method applied to irregular structures.

  1. Simplification of Visual Rendering in Simulated Prosthetic Vision Facilitates Navigation.

    Science.gov (United States)

    Vergnieux, Victor; Macé, Marc J-M; Jouffrais, Christophe

    2017-09-01

    Visual neuroprostheses are still limited and simulated prosthetic vision (SPV) is used to evaluate potential and forthcoming functionality of these implants. SPV has been used to evaluate the minimum requirement on visual neuroprosthetic characteristics to restore various functions such as reading, objects and face recognition, object grasping, etc. Some of these studies focused on obstacle avoidance but only a few investigated orientation or navigation abilities with prosthetic vision. The resolution of current arrays of electrodes is not sufficient to allow navigation tasks without additional processing of the visual input. In this study, we simulated a low resolution array (15 × 18 electrodes, similar to a forthcoming generation of arrays) and evaluated the navigation abilities restored when visual information was processed with various computer vision algorithms to enhance the visual rendering. Three main visual rendering strategies were compared to a control rendering in a wayfinding task within an unknown environment. The control rendering corresponded to a resizing of the original image onto the electrode array size, according to the average brightness of the pixels. In the first rendering strategy, vision distance was limited to 3, 6, or 9 m, respectively. In the second strategy, the rendering was not based on the brightness of the image pixels, but on the distance between the user and the elements in the field of view. In the last rendering strategy, only the edges of the environments were displayed, similar to a wireframe rendering. All the tested renderings, except the 3 m limitation of the viewing distance, improved navigation performance and decreased cognitive load. Interestingly, the distance-based and wireframe renderings also improved the cognitive mapping of the unknown environment. These results show that low resolution implants are usable for wayfinding if specific computer vision algorithms are used to select and display appropriate

  2. Sketchy Rendering for Information Visualization.

    Science.gov (United States)

    Wood, J; Isenberg, P; Isenberg, T; Dykes, J; Boukhelifa, N; Slingsby, A

    2012-12-01

    We present and evaluate a framework for constructing sketchy style information visualizations that mimic data graphics drawn by hand. We provide an alternative renderer for the Processing graphics environment that redefines core drawing primitives including line, polygon and ellipse rendering. These primitives allow higher-level graphical features such as bar charts, line charts, treemaps and node-link diagrams to be drawn in a sketchy style with a specified degree of sketchiness. The framework is designed to be easily integrated into existing visualization implementations with minimal programming modification or design effort. We show examples of use for statistical graphics, conveying spatial imprecision and for enhancing aesthetic and narrative qualities of visualization. We evaluate user perception of sketchiness of areal features through a series of stimulus-response tests in order to assess users' ability to place sketchiness on a ratio scale, and to estimate area. Results suggest relative area judgment is compromised by sketchy rendering and that its influence is dependent on the shape being rendered. They show that degree of sketchiness may be judged on an ordinal scale but that its judgement varies strongly between individuals. We evaluate higher-level impacts of sketchiness through user testing of scenarios that encourage user engagement with data visualization and willingness to critique visualization design. Results suggest that where a visualization is clearly sketchy, engagement may be increased and that attitudes to participating in visualization annotation are more positive. The results of our work have implications for effective information visualization design that go beyond the traditional role of sketching as a tool for prototyping or its use for an indication of general uncertainty.

  3. Integral image rendering procedure for aberration correction and size measurement.

    Science.gov (United States)

    Sommer, Holger; Ihrig, Andreas; Ebenau, Melanie; Flühs, Dirk; Spaan, Bernhard; Eichmann, Marion

    2014-05-20

    The challenge in rendering integral images is to use as much information preserved by the light field as possible to reconstruct a captured scene in a three-dimensional way. We propose a rendering algorithm based on the projection of rays through a detailed simulation of the optical path, considering all the physical properties and locations of the optical elements. The rendered images contain information about the correct size of imaged objects without the need to calibrate the imaging device. Additionally, aberrations of the optical system may be corrected, depending on the setup of the integral imaging device. We show simulation data that illustrates the aberration correction ability and experimental data from our plenoptic camera, which illustrates the capability of our proposed algorithm to measure size and distance. We believe this rendering procedure will be useful in the future for three-dimensional ophthalmic imaging of the human retina.

  4. Application of Adjoint Method and Spectral-Element Method to Tomographic Inversion of Regional Seismological Structure Beneath Japanese Islands

    Science.gov (United States)

    Tsuboi, S.; Miyoshi, T.; Obayashi, M.; Tono, Y.; Ando, K.

    2014-12-01

    Recent progress in large scale computing by using waveform modeling technique and high performance computing facility has demonstrated possibilities to perform full-waveform inversion of three dimensional (3D) seismological structure inside the Earth. We apply the adjoint method (Liu and Tromp, 2006) to obtain 3D structure beneath Japanese Islands. First we implemented Spectral-Element Method to K-computer in Kobe, Japan. We have optimized SPECFEM3D_GLOBE (Komatitsch and Tromp, 2002) by using OpenMP so that the code fits hybrid architecture of K-computer. Now we could use 82,134 nodes of K-computer (657,072 cores) to compute synthetic waveform with about 1 sec accuracy for realistic 3D Earth model and its performance was 1.2 PFLOPS. We use this optimized SPECFEM3D_GLOBE code and take one chunk around Japanese Islands from global mesh and compute synthetic seismograms with accuracy of about 10 second. We use GAP-P2 mantle tomography model (Obayashi et al., 2009) as an initial 3D model and use as many broadband seismic stations available in this region as possible to perform inversion. We then use the time windows for body waves and surface waves to compute adjoint sources and calculate adjoint kernels for seismic structure. We have performed several iteration and obtained improved 3D structure beneath Japanese Islands. The result demonstrates that waveform misfits between observed and theoretical seismograms improves as the iteration proceeds. We now prepare to use much shorter period in our synthetic waveform computation and try to obtain seismic structure for basin scale model, such as Kanto basin, where there are dense seismic network and high seismic activity. Acknowledgements: This research was partly supported by MEXT Strategic Program for Innovative Research. We used F-net seismograms of the National Research Institute for Earth Science and Disaster Prevention.

  5. Spectral element modelling of seismic wave propagation in visco-elastoplastic media including excess-pore pressure development

    Science.gov (United States)

    Oral, Elif; Gélis, Céline; Bonilla, Luis Fabián; Delavaud, Elise

    2017-12-01

    Numerical modelling of seismic wave propagation, considering soil nonlinearity, has become a major topic in seismic hazard studies when strong shaking is involved under particular soil conditions. Indeed, when strong ground motion propagates in saturated soils, pore pressure is another important parameter to take into account when successive phases of contractive and dilatant soil behaviour are expected. Here, we model 1-D seismic wave propagation in linear and nonlinear media using the spectral element numerical method. The study uses a three-component (3C) nonlinear rheology and includes pore-pressure excess. The 1-D-3C model is used to study the 1987 Superstition Hills earthquake (ML 6.6), which was recorded at the Wildlife Refuge Liquefaction Array, USA. The data of this event present strong soil nonlinearity involving pore-pressure effects. The ground motion is numerically modelled for different assumptions on soil rheology and input motion (1C versus 3C), using the recorded borehole signals as input motion. The computed acceleration-time histories show low-frequency amplification and strong high-frequency damping due to the development of pore pressure in one of the soil layers. Furthermore, the soil is found to be more nonlinear and more dilatant under triaxial loading compared to the classical 1C analysis, and significant differences in surface displacements are observed between the 1C and 3C approaches. This study contributes to identify and understand the dominant phenomena occurring in superficial layers, depending on local soil properties and input motions, conditions relevant for site-specific studies.

  6. Numerical Modeling of 3D Seismic Wave Propagation around Yogyakarta, the Southern Part of Central Java, Indonesia, Using Spectral-Element Method on MPI-GPU Cluster

    Science.gov (United States)

    Sudarmaji; Rudianto, Indra; Eka Nurcahya, Budi

    2018-04-01

    A strong tectonic earthquake with a magnitude of 5.9 Richter scale has been occurred in Yogyakarta and Central Java on May 26, 2006. The earthquake has caused severe damage in Yogyakarta and the southern part of Central Java, Indonesia. The understanding of seismic response of earthquake among ground shaking and the level of building damage is important. We present numerical modeling of 3D seismic wave propagation around Yogyakarta and the southern part of Central Java using spectral-element method on MPI-GPU (Graphics Processing Unit) computer cluster to observe its seismic response due to the earthquake. The homogeneous 3D realistic model is generated with detailed topography surface. The influences of free surface topography and layer discontinuity of the 3D model among the seismic response are observed. The seismic wave field is discretized using spectral-element method. The spectral-element method is solved on a mesh of hexahedral elements that is adapted to the free surface topography and the internal discontinuity of the model. To increase the data processing capabilities, the simulation is performed on a GPU cluster with implementation of MPI (Message Passing Interface).

  7. GPU Pro advanced rendering techniques

    CERN Document Server

    Engel, Wolfgang

    2010-01-01

    This book covers essential tools and techniques for programming the graphics processing unit. Brought to you by Wolfgang Engel and the same team of editors who made the ShaderX series a success, this volume covers advanced rendering techniques, engine design, GPGPU techniques, related mathematical techniques, and game postmortems. A special emphasis is placed on handheld programming to account for the increased importance of graphics on mobile devices, especially the iPhone and iPod touch.Example programs and source code can be downloaded from the book's CRC Press web page. 

  8. Immersive volume rendering of blood vessels

    Science.gov (United States)

    Long, Gregory; Kim, Han Suk; Marsden, Alison; Bazilevs, Yuri; Schulze, Jürgen P.

    2012-03-01

    In this paper, we present a novel method of visualizing flow in blood vessels. Our approach reads unstructured tetrahedral data, resamples it, and uses slice based 3D texture volume rendering. Due to the sparse structure of blood vessels, we utilize an octree to efficiently store the resampled data by discarding empty regions of the volume. We use animation to convey time series data, wireframe surface to give structure, and utilize the StarCAVE, a 3D virtual reality environment, to add a fully immersive element to the visualization. Our tool has great value in interdisciplinary work, helping scientists collaborate with clinicians, by improving the understanding of blood flow simulations. Full immersion in the flow field allows for a more intuitive understanding of the flow phenomena, and can be a great help to medical experts for treatment planning.

  9. Accurate quantitative CF-LIBS analysis of both major and minor elements in alloys via iterative correction of plasma temperature and spectral intensity

    Science.gov (United States)

    Shuxia, ZHAO; Lei, ZHANG; Jiajia, HOU; Yang, ZHAO; Wangbao, YIN; Weiguang, MA; Lei, DONG; Liantuan, XIAO; Suotang, JIA

    2018-03-01

    The chemical composition of alloys directly determines their mechanical behaviors and application fields. Accurate and rapid analysis of both major and minor elements in alloys plays a key role in metallurgy quality control and material classification processes. A quantitative calibration-free laser-induced breakdown spectroscopy (CF-LIBS) analysis method, which carries out combined correction of plasma temperature and spectral intensity by using a second-order iterative algorithm and two boundary standard samples, is proposed to realize accurate composition measurements. Experimental results show that, compared to conventional CF-LIBS analysis, the relative errors for major elements Cu and Zn and minor element Pb in the copper-lead alloys has been reduced from 12%, 26% and 32% to 1.8%, 2.7% and 13.4%, respectively. The measurement accuracy for all elements has been improved substantially.

  10. Binaural Rendering in MPEG Surround

    Directory of Open Access Journals (Sweden)

    Kristofer Kjörling

    2008-04-01

    Full Text Available This paper describes novel methods for evoking a multichannel audio experience over stereo headphones. In contrast to the conventional convolution-based approach where, for example, five input channels are filtered using ten head-related transfer functions, the current approach is based on a parametric representation of the multichannel signal, along with either a parametric representation of the head-related transfer functions or a reduced set of head-related transfer functions. An audio scene with multiple virtual sound sources is represented by a mono or a stereo downmix signal of all sound source signals, accompanied by certain statistical (spatial properties. These statistical properties of the sound sources are either combined with statistical properties of head-related transfer functions to estimate “binaural parameters” that represent the perceptually relevant aspects of the auditory scene or used to create a limited set of combined head-related transfer functions that can be applied directly on the downmix signal. Subsequently, a binaural rendering stage reinstates the statistical properties of the sound sources by applying the estimated binaural parameters or the reduced set of combined head-related transfer functions directly on the downmix. If combined with parametric multichannel audio coders such as MPEG Surround, the proposed methods are advantageous over conventional methods in terms of perceived quality and computational complexity.

  11. NURBS-SEM: a hybrid spectral element method on NURBS maps for the solution of elliptic PDEs on surfaces

    OpenAIRE

    Pitton, Giuseppe; Heltai, Luca

    2018-01-01

    Non Uniform Rational B-spline (NURBS) patches are a standard way to describe complex geometries in Computer Aided Design tools, and have gained a lot of popularity in recent years also for the approximation of partial differential equations, via the Isogeometric Analysis (IGA) paradigm. However, spectral accuracy in IGA is limited to relatively small NURBS patch degrees (roughly p

  12. A high-order 3-D spectral-element method for the forward modelling and inversion of gravimetric data—Application to the western Pyrenees

    Science.gov (United States)

    Martin, Roland; Chevrot, Sébastien; Komatitsch, Dimitri; Seoane, Lucia; Spangenberg, Hannah; Wang, Yi; Dufréchou, Grégory; Bonvalot, Sylvain; Bruinsma, Sean

    2017-04-01

    We image the internal density structure of the Pyrenees by inverting gravity data using an a priori density model derived by scaling a Vp model obtained by full waveform inversion of teleseismic P-waves. Gravity anomalies are computed via a 3-D high-order finite-element integration in the same high-order spectral-element grid as the one used to solve the wave equation and thus to obtain the velocity model. The curvature of the Earth and surface topography are taken into account in order to obtain a density model as accurate as possible. The method is validated through comparisons with exact semi-analytical solutions. We show that the spectral-element method drastically accelerates the computations when compared to other more classical methods. Different scaling relations between compressional velocity and density are tested, and the Nafe-Drake relation is the one that leads to the best agreement between computed and observed gravity anomalies. Gravity data inversion is then performed and the results allow us to put more constraints on the density structure of the shallow crust and on the deep architecture of the mountain range.

  13. Method and system for rendering and interacting with an adaptable computing environment

    Science.gov (United States)

    Osbourn, Gordon Cecil [Albuquerque, NM; Bouchard, Ann Marie [Albuquerque, NM

    2012-06-12

    An adaptable computing environment is implemented with software entities termed "s-machines", which self-assemble into hierarchical data structures capable of rendering and interacting with the computing environment. A hierarchical data structure includes a first hierarchical s-machine bound to a second hierarchical s-machine. The first hierarchical s-machine is associated with a first layer of a rendering region on a display screen and the second hierarchical s-machine is associated with a second layer of the rendering region overlaying at least a portion of the first layer. A screen element s-machine is linked to the first hierarchical s-machine. The screen element s-machine manages data associated with a screen element rendered to the display screen within the rendering region at the first layer.

  14. Image Based Rendering and Virtual Reality

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    The Presentation concerns with an overview of Image Based Rendering approaches and their use on Virtual Reality, including Virtual Photography and Cinematography, and Mobile Robot Navigation.......The Presentation concerns with an overview of Image Based Rendering approaches and their use on Virtual Reality, including Virtual Photography and Cinematography, and Mobile Robot Navigation....

  15. Moisture movements in render on brick wall

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Munch, Thomas Astrup; Thorsen, Peter Schjørmann

    2003-01-01

    A three-layer render on brick wall used for building facades is studied in the laboratory. The vertical render surface is held in contact with water for 24 hours simulating driving rain while it is measured with non-destructive X-ray equipment every hour in order to follow the moisture front...

  16. Physically based rendering from theory to implementation

    CERN Document Server

    Pharr, Matt

    2010-01-01

    "Physically Based Rendering, 2nd Edition" describes both the mathematical theory behind a modern photorealistic rendering system as well as its practical implementation. A method - known as 'literate programming'- combines human-readable documentation and source code into a single reference that is specifically designed to aid comprehension. The result is a stunning achievement in graphics education. Through the ideas and software in this book, you will learn to design and employ a full-featured rendering system for creating stunning imagery. This book features new sections on subsurface scattering, Metropolis light transport, precomputed light transport, multispectral rendering, and much more. It includes a companion site complete with source code for the rendering system described in the book, with support for Windows, OS X, and Linux. Code and text are tightly woven together through a unique indexing feature that lists each function, variable, and method on the page that they are first described.

  17. Spectral Resolution for Five-Element, Filtered, X-Ray Detector (XRD) Arrays Using the Methods of Backus and Gilbert

    International Nuclear Information System (INIS)

    FEHL, DAVID LEE; BIGGS, F.; CHANDLER, GORDON A.; STYGAR, WILLIAM A.

    2000-01-01

    The generalized method of Backus and Gilbert (BG) is described and applied to the inverse problem of obtaining spectra from a 5-channel, filtered array of x-ray detectors (XRD's). This diagnostic is routinely fielded on the Z facility at Sandia National Laboratories to study soft x-ray photons ((le)2300 eV), emitted by high density Z-pinch plasmas. The BG method defines spectral resolution limits on the system of response functions that are in good agreement with the unfold method currently in use. The resolution so defined is independent of the source spectrum. For noise-free, simulated data the BG approximating function is also in reasonable agreement with the source spectrum (150 eV black-body) and the unfold. This function may be used as an initial trial function for iterative methods or a regularization model

  18. An empirical method for determination of elemental components of radiated powers and impurity concentrations from VUV and XUV spectral features in tokamak plasmas

    International Nuclear Information System (INIS)

    Lawson, K.; Peacock, N.; Gianella, R.

    1998-12-01

    The derivation of elemental components of radiated powers and impurity concentrations in bulk tokamak plasmas is complex, often requiring a full description of the impurity transport. A novel, empirical method, the Line Intensity Normalization Technique (LINT) has been developed on the JET (Joint European Torus) tokamak to provide routine information about the impurity content of the plasma and elemental components of radiated power (P rad ). The technique employs a few VUV and XUV resonance line intensities to represent the intrinsic impurity elements in the plasma. From a data base comprising these spectral features, the total bolometric measurement of the radiated power and the Z eff measured by visible spectroscopy, separate elemental components of P rad and Z eff are derived. The method, which converts local spectroscopic signals into global plasma parameters, has the advantage of simplicity, allowing large numbers of pulses to be processed, and, in many operational modes of JET, is found to be both reliable and accurate. It relies on normalizing the line intensities to the absolute calibration of the bolometers and visible spectrometers, using coefficients independent of density and temperature. Accuracies of the order of ± 15% can be achieved for the elemental P rad components of the most significant impurities and the impurity concentrations can be determined to within ±30%. Trace elements can be monitored, although with reduced accuracy. The present paper deals with limiter discharges, which have been the main application to date. As a check on the technique and to demonstrate the value of the LINT results, they have been applied to the transport modelling of intrinsic impurities carried out with the SANCO transport code, which uses atomic data from ADAS. The simulations provide independent confirmation of the concentrations empirically derived using the LINT technique. For this analysis, the simple case of the L-mode regime is considered, the chosen

  19. Mixed spectral finite elements and perfectly matched layers for elastic waves in time domain; Elements finis mixtes spectraux et couches absorbantes parfaitement adaptees pour la propagation d'ondes elastiques en regime transitoire

    Energy Technology Data Exchange (ETDEWEB)

    Fauqueux, S.

    2003-02-01

    We consider the propagation of elastic waves in unbounded domains. A new formulation of the linear elasticity system as an H (div) - L{sup 2} system enables us to use the 'mixed spectral finite element method', This new method is based on the definition of new spaces of approximation and the use of mass-lumping. It leads to an explicit scheme with reduced storage and provides the same solution as the spectral finite element method. Then, we model unbounded domains by using Perfectly Matched Layers. Instabilities in the PML in the case of particular 2D elastic media are pointed out and investigated. The numerical method is validated and tested in the case of acoustic and elastic realistic models. A plane wave analysis gives results about numerical dispersion and shows that meshes adapted to the physical and geometrical properties of the media are more accurate than the others. Then, an extension of the method to fluid-solid coupling is introduced for 2D seismic propagation. (author)

  20. RenderGAN: Generating Realistic Labeled Data

    Directory of Open Access Journals (Sweden)

    Leon Sixt

    2018-06-01

    Full Text Available Deep Convolutional Neuronal Networks (DCNNs are showing remarkable performance on many computer vision tasks. Due to their large parameter space, they require many labeled samples when trained in a supervised setting. The costs of annotating data manually can render the use of DCNNs infeasible. We present a novel framework called RenderGAN that can generate large amounts of realistic, labeled images by combining a 3D model and the Generative Adversarial Network framework. In our approach, image augmentations (e.g., lighting, background, and detail are learned from unlabeled data such that the generated images are strikingly realistic while preserving the labels known from the 3D model. We apply the RenderGAN framework to generate images of barcode-like markers that are attached to honeybees. Training a DCNN on data generated by the RenderGAN yields considerably better performance than training it on various baselines.

  1. Absolute sensitivity calibration from 20 A to 430 A of a grazing incidence spectrometer with a multi-element spectral detector

    International Nuclear Information System (INIS)

    Terry, J.L.; Manning, H.L.; Marmar, E.S.

    1986-07-01

    Two methods which together allow sensitivity calibration from 20 A to 430 A are described in detail. The first method, useful up to 120 A, uses a low power source to generate Kα x-rays which are alternately viewed by an absolute detector (a proportional counter) and the spectrometer. The second method extends that calibration to 430 A. It relies on the 2:1 brightness ratio of bright doublet lines from impurity ions which have a single outer shell electron and which are present in hot, magnetically confined plasmas. It requires that the absolute sensitivity of the spectrometer be known at one wavelength point, and in practice requires a multi-element spectral detector

  2. A Real-Time Sound Field Rendering Processor

    Directory of Open Access Journals (Sweden)

    Tan Yiyu

    2017-12-01

    Full Text Available Real-time sound field renderings are computationally intensive and memory-intensive. Traditional rendering systems based on computer simulations suffer from memory bandwidth and arithmetic units. The computation is time-consuming, and the sample rate of the output sound is low because of the long computation time at each time step. In this work, a processor with a hybrid architecture is proposed to speed up computation and improve the sample rate of the output sound, and an interface is developed for system scalability through simply cascading many chips to enlarge the simulated area. To render a three-minute Beethoven wave sound in a small shoe-box room with dimensions of 1.28 m × 1.28 m × 0.64 m, the field programming gate array (FPGA-based prototype machine with the proposed architecture carries out the sound rendering at run-time while the software simulation with the OpenMP parallelization takes about 12.70 min on a personal computer (PC with 32 GB random access memory (RAM and an Intel i7-6800K six-core processor running at 3.4 GHz. The throughput in the software simulation is about 194 M grids/s while it is 51.2 G grids/s in the prototype machine even if the clock frequency of the prototype machine is much lower than that of the PC. The rendering processor with a processing element (PE and interfaces consumes about 238,515 gates after fabricated by the 0.18 µm processing technology from the ROHM semiconductor Co., Ltd. (Kyoto Japan, and the power consumption is about 143.8 mW.

  3. Distributed rendering for multiview parallax displays

    Science.gov (United States)

    Annen, T.; Matusik, W.; Pfister, H.; Seidel, H.-P.; Zwicker, M.

    2006-02-01

    3D display technology holds great promise for the future of television, virtual reality, entertainment, and visualization. Multiview parallax displays deliver stereoscopic views without glasses to arbitrary positions within the viewing zone. These systems must include a high-performance and scalable 3D rendering subsystem in order to generate multiple views at real-time frame rates. This paper describes a distributed rendering system for large-scale multiview parallax displays built with a network of PCs, commodity graphics accelerators, multiple projectors, and multiview screens. The main challenge is to render various perspective views of the scene and assign rendering tasks effectively. In this paper we investigate two different approaches: Optical multiplexing for lenticular screens and software multiplexing for parallax-barrier displays. We describe the construction of large-scale multi-projector 3D display systems using lenticular and parallax-barrier technology. We have developed different distributed rendering algorithms using the Chromium stream-processing framework and evaluate the trade-offs and performance bottlenecks. Our results show that Chromium is well suited for interactive rendering on multiview parallax displays.

  4. Visualization of plasma collision phenomenon by particle based rendering

    International Nuclear Information System (INIS)

    Yamamoto, Takeshi; Takagishi, Hironori; Hasegawa, Kyoko; Nakata, Susumu; Tanaka, Satoshi; Tanaka, Kazuo

    2012-01-01

    In this paper, we visualize plasma collision phenomenon based on XYT-space (space and time) volume data for supporting research in plasma physics. We create 3D volume data in the XYT-space by piling up a time series of XY-plane photo images taken in experiment. As a result, we can visualize as one still image all the time behavior of the plasma plume. Besides, we adopt 'fused' visualization based on particle based rendering technique. Using that technique, we can easily fuse volume rendering different materials, and compare physics of different elements in flexible ways. In addition, we propose the method to generate pseudo-3D images from pictures shoot by ICCD of two perspectives on the upper and side. (author)

  5. Standardized rendering from IR surveillance motion imagery

    Science.gov (United States)

    Prokoski, F. J.

    2014-06-01

    Government agencies, including defense and law enforcement, increasingly make use of video from surveillance systems and camera phones owned by non-government entities.Making advanced and standardized motion imaging technology available to private and commercial users at cost-effective prices would benefit all parties. In particular, incorporating thermal infrared into commercial surveillance systems offers substantial benefits beyond night vision capability. Face rendering is a process to facilitate exploitation of thermal infrared surveillance imagery from the general area of a crime scene, to assist investigations with and without cooperating eyewitnesses. Face rendering automatically generates greyscale representations similar to police artist sketches for faces in surveillance imagery collected from proximate locations and times to a crime under investigation. Near-realtime generation of face renderings can provide law enforcement with an investigation tool to assess witness memory and credibility, and integrate reports from multiple eyewitnesses, Renderings can be quickly disseminated through social media to warn of a person who may pose an immediate threat, and to solicit the public's help in identifying possible suspects and witnesses. Renderings are pose-standardized so as to not divulge the presence and location of eyewitnesses and surveillance cameras. Incorporation of thermal infrared imaging into commercial surveillance systems will significantly improve system performance, and reduce manual review times, at an incremental cost that will continue to decrease. Benefits to criminal justice would include improved reliability of eyewitness testimony and improved accuracy of distinguishing among minority groups in eyewitness and surveillance identifications.

  6. Earth mortars and earth-lime renders

    Directory of Open Access Journals (Sweden)

    Maria Fernandes

    2008-01-01

    Full Text Available Earth surface coatings play a decorative architectural role, apart from their function as wall protection. In Portuguese vernacular architecture, earth mortars were usually applied on stone masonry, while earth renders and plasters were used on indoors surface coatings. Limestone exists only in certain areas of the country and consequently lime was not easily available everywhere, especially on granite and schist regions where stone masonry was a current building technique. In the central west coast of Portugal, the lime slaking procedure entailed slaking the quicklime mixed with earth (sandy soil, in a pit; the resulting mixture would then be combined in a mortar or plaster. This was also the procedure for manufactured adobes stabilized with lime. Adobe buildings with earth-lime renderings and plasters were also traditional in the same region, using lime putty and lime wash for final coat and decoration. Classic decoration on earth architecture from the 18th-19th century was in many countries a consequence of the François Cointeraux (1740-1830 manuals - Les Cahiers d'Architecture Rurale" (1793 - a French guide for earth architecture and building construction. This manual arrived to Portugal in the beginning of XIX century, but was never translated to Portuguese. References about decoration for earth houses were explained on this manual, as well as procedures about earth-lime renders and ornamentation of earth walls; in fact, these procedures are exactly the same as the ones used in adobe buildings in this Portuguese region. The specific purpose of the present paper is to show some cases of earth mortars, renders and plasters on stone buildings in Portugal and to explain the methods of producing earth-lime renders, and also to show some examples of rendering and coating with earth-lime in Portuguese adobe vernacular architecture.

  7. Digital color acquisition, perception, coding and rendering

    CERN Document Server

    Fernandez-Maloigne, Christine; Macaire, Ludovic

    2013-01-01

    In this book the authors identify the basic concepts and recent advances in the acquisition, perception, coding and rendering of color. The fundamental aspects related to the science of colorimetry in relation to physiology (the human visual system) are addressed, as are constancy and color appearance. It also addresses the more technical aspects related to sensors and the color management screen. Particular attention is paid to the notion of color rendering in computer graphics. Beyond color, the authors also look at coding, compression, protection and quality of color images and videos.

  8. Haptic rendering for simulation of fine manipulation

    CERN Document Server

    Wang, Dangxiao; Zhang, Yuru

    2014-01-01

    This book introduces the latest progress in six degrees of freedom (6-DoF) haptic rendering with the focus on a new approach for simulating force/torque feedback in performing tasks that require dexterous manipulation skills. One of the major challenges in 6-DoF haptic rendering is to resolve the conflict between high speed and high fidelity requirements, especially in simulating a tool interacting with both rigid and deformable objects in a narrow space and with fine features. The book presents a configuration-based optimization approach to tackle this challenge. Addressing a key issue in man

  9. Blender cycles lighting and rendering cookbook

    CERN Document Server

    Iraci, Bernardo

    2013-01-01

    An in-depth guide full of step-by-step recipes to explore the concepts behind the usage of Cycles. Packed with illustrations, and lots of tips and tricks; the easy-to-understand nature of the book will help the reader understand even the most complex concepts with ease.If you are a digital artist who already knows your way around Blender, and you want to learn about the new Cycles' rendering engine, this is the book for you. Even experts will be able to pick up new tips and tricks to make the most of the rendering capabilities of Cycles.

  10. GPU Pro 5 advanced rendering techniques

    CERN Document Server

    Engel, Wolfgang

    2014-01-01

    In GPU Pro5: Advanced Rendering Techniques, section editors Wolfgang Engel, Christopher Oat, Carsten Dachsbacher, Michal Valient, Wessam Bahnassi, and Marius Bjorge have once again assembled a high-quality collection of cutting-edge techniques for advanced graphics processing unit (GPU) programming. Divided into six sections, the book covers rendering, lighting, effects in image space, mobile devices, 3D engine design, and compute. It explores rasterization of liquids, ray tracing of art assets that would otherwise be used in a rasterized engine, physically based area lights, volumetric light

  11. Fast rendering of scanned room geometries

    DEFF Research Database (Denmark)

    Olesen, Søren Krarup; Markovic, Milos; Hammershøi, Dorte

    2014-01-01

    Room acoustics are rendered in Virtual Realities based on models of the real world. These are typically rather coarse representations of the true geometry resulting in room impulse responses with a lack of natural detail. This problem can be overcome by using data scanned by sensors, such as e...

  12. Rendering Visible: Painting and Sexuate Subjectivity

    Science.gov (United States)

    Daley, Linda

    2015-01-01

    In this essay, I examine Luce Irigaray's aesthetic of sexual difference, which she develops by extrapolating from Paul Klee's idea that the role of painting is to render the non-visible rather than represent the visible. This idea is the premise of her analyses of phenomenology and psychoanalysis and their respective contributions to understanding…

  13. Free-viewpoint depth image based rendering

    NARCIS (Netherlands)

    Zinger, S.; Do, Q.L.; With, de P.H.N.

    2010-01-01

    In 3D TV research, one approach is to employ multiple cameras for creating a 3D multi-view signal with the aim to make interactive free-viewpoint selection possible in 3D TV media. This paper explores a new rendering algorithm that enables to compute a free-viewpoint between two reference views from

  14. Insight on the anisotropic nature of the D'' layer through the analysis of SKS-SKKS splitting obtained via 3D spectral element modeling

    Science.gov (United States)

    Tesoniero, A.; Leng, K.; Long, M. D.; Nissen-Meyer, T.

    2017-12-01

    Constraining the nature of the anisotropy in the core-mantle boundary region is a key factor for properly predicting the flow of the lowermost mantle. The lack of seismic waves sampling this region and their uneven azimuthal distribution hamper a correct representation of mantle dynamics. We present preliminary results for a series of SKS-SKKS splitting analysis based on numerical forward synthetic tests in a realistic 3-D Earth model using the software AXISEM3D, a newly developed efficient hybrid spectral element method solver for 3-D structures. The anisotropic property of the computational domain in the bottom 300km of the Earth's mantle is fully described with a fourth-order elastic tensor with 21 independent coefficients. We tested a single crystal mineralogy of postperovskite with different orientations that are consistent with realistic mantle flow models and accounted for a wide coverage of azimuthal seismic raypaths. We take advantage of the computational efficiency of the method to achieve resolutions for seismic periods as low as 8s. Our preliminary results, based on forward full waveform modeling, represent a step forward for validating hypotheses for the anisotropy in the D'' layer derived by direct splitting measurements and ray-theoretical mineral physics based modeling tests. Our study also highlights the capability of AXISEM3D to handle high degrees of model complexity in full anisotropy and its potentials for future endeavours.

  15. High frequency dynamics of an isotropic Timoshenko periodic beam by the use of the Time-domain Spectral Finite Element Method

    Science.gov (United States)

    Żak, A.; Krawczuk, M.; Palacz, M.; Doliński, Ł.; Waszkowiak, W.

    2017-11-01

    In this work results of numerical simulations and experimental measurements related to the high frequency dynamics of an aluminium Timoshenko periodic beam are presented. It was assumed by the authors that the source of beam structural periodicity comes from periodical alterations to its geometry due to the presence of appropriately arranged drill-holes. As a consequence of these alterations dynamic characteristics of the beam are changed revealing a set of frequency band gaps. The presence of the frequency band gaps can help in the design process of effective sound filters or sound barriers that can selectively attenuate propagating wave signals of certain frequency contents. In order to achieve this a combination of three numerical techniques were employed by the authors. They comprise the application of the Time-domain Spectral Finite Element Method in the case of analysis of finite and semi-infinite computational domains, damage modelling in the case of analysis of drill-hole influence, as well as the Bloch reduction in the case of analysis of periodic computational domains. As an experimental technique the Scanning Laser Doppler Vibrometry was chosen. A combined application of all these numerical and experimental techniques appears as new for this purpose and not reported in the literature available.

  16. Application of the finite-element method and the eigenmode expansion method to investigate the periodic and spectral characteristic of discrete phase-shift fiber Bragg grating

    Science.gov (United States)

    He, Yue-Jing; Hung, Wei-Chih; Syu, Cheng-Jyun

    2017-12-01

    The finite-element method (FEM) and eigenmode expansion method (EEM) were adopted to analyze the guided modes and spectrum of phase-shift fiber Bragg grating at five phase-shift degrees (including zero, 1/4π, 1/2π, 3/4π, and π). In previous studies on optical fiber grating, conventional coupled-mode theory was crucial. This theory contains abstruse knowledge about physics and complex computational processes, and thus is challenging for users. Therefore, a numerical simulation method was coupled with a simple and rigorous design procedure to help beginners and users to overcome difficulty in entering the field; in addition, graphical simulation results were presented. To reduce the difference between the simulated context and the actual context, a perfectly matched layer and perfectly reflecting boundary were added to the FEM and the EEM. When the FEM was used for grid cutting, the object meshing method and the boundary meshing method proposed in this study were used to effectively enhance computational accuracy and substantially reduce the time required for simulation. In summary, users can use the simulation results in this study to easily and rapidly design an optical fiber communication system and optical sensors with spectral characteristics.

  17. DNS of Low-Pressure Turbine Cascade Flows with Elevated Inflow Turbulence Using a Discontinuous-Galerkin Spectral-Element Method

    Science.gov (United States)

    Garai, Anirban; Diosady, Laslo T.; Murman, Scott M.; Madavan, Nateri K.

    2016-01-01

    Recent progress towards developing a new computational capability for accurate and efficient high-fidelity direct numerical simulation (DNS) and large-eddy simulation (LES) of turbomachinery is described. This capability is based on an entropy- stable Discontinuous-Galerkin spectral-element approach that extends to arbitrarily high orders of spatial and temporal accuracy, and is implemented in a computationally efficient manner on a modern high performance computer architecture. An inflow turbulence generation procedure based on a linear forcing approach has been incorporated in this framework and DNS conducted to study the effect of inflow turbulence on the suction- side separation bubble in low-pressure turbine (LPT) cascades. The T106 series of airfoil cascades in both lightly (T106A) and highly loaded (T106C) configurations at exit isentropic Reynolds numbers of 60,000 and 80,000, respectively, are considered. The numerical simulations are performed using 8th-order accurate spatial and 4th-order accurate temporal discretization. The changes in separation bubble topology due to elevated inflow turbulence is captured by the present method and the physical mechanisms leading to the changes are explained. The present results are in good agreement with prior numerical simulations but some expected discrepancies with the experimental data for the T106C case are noted and discussed.

  18. Spectral element simulation of ultrafiltration

    DEFF Research Database (Denmark)

    Hansen, M.; Barker, Vincent A.; Hassager, Ole

    1998-01-01

    for the unknowns at the mesh nodes. This system is solved via a technique combining the penalty method, Newton-Raphson iterations, static condensation, and a solver for banded linear systems. In addition, a smoothing technique is used to handle a singularity in the boundary condition at the membrane...

  19. The rendering context for stereoscopic 3D web

    Science.gov (United States)

    Chen, Qinshui; Wang, Wenmin; Wang, Ronggang

    2014-03-01

    3D technologies on the Web has been studied for many years, but they are basically monoscopic 3D. With the stereoscopic technology gradually maturing, we are researching to integrate the binocular 3D technology into the Web, creating a stereoscopic 3D browser that will provide users with a brand new experience of human-computer interaction. In this paper, we propose a novel approach to apply stereoscopy technologies to the CSS3 3D Transforms. Under our model, each element can create or participate in a stereoscopic 3D rendering context, in which 3D Transforms such as scaling, translation and rotation, can be applied and be perceived in a truly 3D space. We first discuss the underlying principles of stereoscopy. After that we discuss how these principles can be applied to the Web. A stereoscopic 3D browser with backward compatibility is also created for demonstration purposes. We take advantage of the open-source WebKit project, integrating the 3D display ability into the rendering engine of the web browser. For each 3D web page, our 3D browser will create two slightly different images, each representing the left-eye view and right-eye view, both to be combined on the 3D display to generate the illusion of depth. And as the result turns out, elements can be manipulated in a truly 3D space.

  20. RAY TRACING RENDER MENGGUNAKAN FRAGMENT ANTI ALIASING

    Directory of Open Access Journals (Sweden)

    Febriliyan Samopa

    2008-07-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Rendering is generating surface and three-dimensional effects on an object displayed on a monitor screen. Ray tracing as a rendering method that traces ray for each image pixel has a drawback, that is, aliasing (jaggies effect. There are some methods for executing anti aliasing. One of those methods is OGSS (Ordered Grid Super Sampling. OGSS is able to perform aliasing well. However, this method requires more computation time since sampling of all pixels in the image will be increased. Fragment Anti Aliasing (FAA is a new alternative method that can cope with the drawback. FAA will check the image when performing rendering to a scene. Jaggies effect is only happened at curve and gradient object. Therefore, only this part of object that will experience sampling magnification. After this sampling magnification and the pixel values are computed, then downsample is performed to retrieve the original pixel values. Experimental results show that the software can implement ray tracing well in order to form images, and it can implement FAA and OGSS technique to perform anti aliasing. In general, rendering using FAA is faster than using OGSS

  1. Rendering Falling Leaves on Graphics Hardware

    OpenAIRE

    Marcos Balsa; Pere-Pau Vázquez

    2008-01-01

    There is a growing interest in simulating natural phenomena in computer graphics applications. Animating natural scenes in real time is one of the most challenging problems due to the inherent complexity of their structure, formed by millions of geometric entities, and the interactions that happen within. An example of natural scenario that is needed for games or simulation programs are forests. Forests are difficult to render because the huge amount of geometric entities and the large amount...

  2. Emission of VOC's from modified rendering process

    International Nuclear Information System (INIS)

    Bhatti, Z.A.; Raja, I.A.; Saddique, M.; Langenhove, H.V.

    2005-01-01

    Rendering technique for processing of dead animal and slaughterhouse wastes into valuable products. It involves cooking of raw material and later Sterilization was added to reduce the Bovine Spongiform Encephalopathy (BSE). Studies have been carried out on rendering emission, with the normal cooking process. Our study shows, that the sterilization step in rendering process increases the emission of volatile organic compounds (VOC's). Gas samples, containing VOC's, were analyzed by the GC/MS (Gas Chromatograph and Mass Spectrometry). The most important groups of compounds- alcohols and cyclic hydrocarbons were identified. In the group of alcohol; 1-butanol, l-pentanol and l-hexanol compounds were found while in the group of cyclic hydrocarbon; methyl cyclopentane and cyclohexane compounds were detected. Other groups like aldehyde, sulphur containing compounds, ketone and furan were also found. Some compounds, like l-pentanol, 2-methyl propanal, dimethyl disulfide and dimethyl trisulfide, which belong to these groups, cause malodor. It is important to know these compounds to treat odorous gasses. (author)

  3. Adding the s-Process Element Cerium to the APOGEE Survey: Identification and Characterization of Ce II Lines in the H-band Spectral Window

    Science.gov (United States)

    Cunha, Katia; Smith, Verne V.; Hasselquist, Sten; Souto, Diogo; Shetrone, Matthew D.; Allende Prieto, Carlos; Bizyaev, Dmitry; Frinchaboy, Peter; García-Hernández, D. Anibal; Holtzman, Jon; Johnson, Jennifer A.; Jőnsson, Henrik; Majewski, Steven R.; Mészáros, Szabolcs; Nidever, David; Pinsonneault, Mark; Schiavon, Ricardo P.; Sobeck, Jennifer; Skrutskie, Michael F.; Zamora, Olga; Zasowski, Gail; Fernández-Trincado, J. G.

    2017-08-01

    Nine Ce II lines have been identified and characterized within the spectral window observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey (between λ1.51 and 1.69 μm). At solar metallicities, cerium is an element that is produced predominantly as a result of the slow capture of neutrons (the s-process) during asymptotic giant branch stellar evolution. The Ce II lines were identified using a combination of a high-resolution (R=λ /δ λ ={{100,000}}) Fourier Transform Spectrometer (FTS) spectrum of α Boo and an APOGEE spectrum (R = 22,400) of a metal-poor, but s-process enriched, red giant (2M16011638-1201525). Laboratory oscillator strengths are not available for these lines. Astrophysical gf-values were derived using α Boo as a standard star, with the absolute cerium abundance in α Boo set by using optical Ce II lines that have precise published laboratory gf-values. The near-infrared Ce II lines identified here are also analyzed, as consistency checks, in a small number of bright red giants using archival FTS spectra, as well as a small sample of APOGEE red giants, including two members of the open cluster NGC 6819, two field stars, and seven metal-poor N- and Al-rich stars. The conclusion is that this set of Ce II lines can be detected and analyzed in a large fraction of the APOGEE red giant sample and will be useful for probing chemical evolution of the s-process products in various populations of the Milky Way.

  4. Wave propagation simulation in the upper core of sodium-cooled fast reactors using a spectral-element method for heterogeneous media

    Science.gov (United States)

    Nagaso, Masaru; Komatitsch, Dimitri; Moysan, Joseph; Lhuillier, Christian

    2018-01-01

    ASTRID project, French sodium cooled nuclear reactor of 4th generation, is under development at the moment by Alternative Energies and Atomic Energy Commission (CEA). In this project, development of monitoring techniques for a nuclear reactor during operation are identified as a measure issue for enlarging the plant safety. Use of ultrasonic measurement techniques (e.g. thermometry, visualization of internal objects) are regarded as powerful inspection tools of sodium cooled fast reactors (SFR) including ASTRID due to opacity of liquid sodium. In side of a sodium cooling circuit, heterogeneity of medium occurs because of complex flow state especially in its operation and then the effects of this heterogeneity on an acoustic propagation is not negligible. Thus, it is necessary to carry out verification experiments for developments of component technologies, while such kind of experiments using liquid sodium may be relatively large-scale experiments. This is why numerical simulation methods are essential for preceding real experiments or filling up the limited number of experimental results. Though various numerical methods have been applied for a wave propagation in liquid sodium, we still do not have a method for verifying on three-dimensional heterogeneity. Moreover, in side of a reactor core being a complex acousto-elastic coupled region, it has also been difficult to simulate such problems with conventional methods. The objective of this study is to solve these 2 points by applying three-dimensional spectral element method. In this paper, our initial results on three-dimensional simulation study on heterogeneous medium (the first point) are shown. For heterogeneity of liquid sodium to be considered, four-dimensional temperature field (three spatial and one temporal dimension) calculated by computational fluid dynamics (CFD) with Large-Eddy Simulation was applied instead of using conventional method (i.e. Gaussian Random field). This three-dimensional numerical

  5. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Sherwood, D.G.; Wilson, J.F.; Salton, R.B.; Fensterer, H.F.

    1981-01-01

    A mechanical spectral shift reactor comprises apparatus for inserting and withdrawing water displacer elements from the reactor core for selectively changing the water-moderator volume in the core thereby changing the reactivity of the core. The apparatus includes drivemechanisms for moving the displacer elements relative to the core and guide mechanisms for guiding the displayer rods through the reactor vessel

  6. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Sherwood, D.G.; Wilson, J.F.; Salton, R.B.; Fensterer, H.F.

    1982-01-01

    A mechanical spectral shift reactor comprises apparatus for inserting and withdrawing water displacer elements from the reactor core for selectively changing the water-moderator volume in the core thereby changing the reactivity of the core. The apparatus includes drive mechanisms for moving the displacer elements relative to the core and guide mechanisms for guiding the displacer rods through the reactor vessel. (author)

  7. Haptic rendering foundations, algorithms, and applications

    CERN Document Server

    Lin, Ming C

    2008-01-01

    For a long time, human beings have dreamed of a virtual world where it is possible to interact with synthetic entities as if they were real. It has been shown that the ability to touch virtual objects increases the sense of presence in virtual environments. This book provides an authoritative overview of state-of-theart haptic rendering algorithms and their applications. The authors examine various approaches and techniques for designing touch-enabled interfaces for a number of applications, including medical training, model design, and maintainability analysis for virtual prototyping, scienti

  8. GPU Pro 4 advanced rendering techniques

    CERN Document Server

    Engel, Wolfgang

    2013-01-01

    GPU Pro4: Advanced Rendering Techniques presents ready-to-use ideas and procedures that can help solve many of your day-to-day graphics programming challenges. Focusing on interactive media and games, the book covers up-to-date methods producing real-time graphics. Section editors Wolfgang Engel, Christopher Oat, Carsten Dachsbacher, Michal Valient, Wessam Bahnassi, and Sebastien St-Laurent have once again assembled a high-quality collection of cutting-edge techniques for advanced graphics processing unit (GPU) programming. Divided into six sections, the book begins with discussions on the abi

  9. GPU PRO 3 Advanced rendering techniques

    CERN Document Server

    Engel, Wolfgang

    2012-01-01

    GPU Pro3, the third volume in the GPU Pro book series, offers practical tips and techniques for creating real-time graphics that are useful to beginners and seasoned game and graphics programmers alike. Section editors Wolfgang Engel, Christopher Oat, Carsten Dachsbacher, Wessam Bahnassi, and Sebastien St-Laurent have once again brought together a high-quality collection of cutting-edge techniques for advanced GPU programming. With contributions by more than 50 experts, GPU Pro3: Advanced Rendering Techniques covers battle-tested tips and tricks for creating interesting geometry, realistic sha

  10. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Wilson, J.F.; Sherwood, D.G.

    1982-01-01

    A mechanical spectral shift reactor comprises a reactive core having fuel assemblies accommodating both water displacer elements and neutron absorbing control rods for selectively changing the volume of water-moderator in the core. The fuel assemblies with displacer and control rods are arranged in alternating fashion so that one displacer element drive mechanism may move displacer elements in more than one fuel assembly without interfering with the movement of control rods of a corresponding control rod drive mechanisms. (author)

  11. Validation of a colour rendering index based on memory colours

    OpenAIRE

    Smet, Kevin; Jost-Boissard, Sophie; Ryckaert, Wouter; Deconinck, Geert; Hanselaer, Peter

    2010-01-01

    In this paper the performance of a colour rendering index based on memory colours is investigated in comparison with the current CIE Colour Rendering Index, the NIST Colour Quality Scale and visual appreciation results obtained at CNRS at Lyon University for a set of 3000K and 4000K LED light sources. The Pearson and Spearman correlation coefficients between each colour rendering metric and the two sets of visual results were calculated. It was found that the memory colour based colour render...

  12. Photon Differential Splatting for Rendering Caustics

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Schjøth, Lars; Erleben, Kenny

    2014-01-01

    We present a photon splatting technique which reduces noise and blur in the rendering of caustics. Blurring of illumination edges is an inherent problem in photon splatting, as each photon is unaware of its neighbours when being splatted. This means that the splat size is usually based...... on heuristics rather than knowledge of the local flux density. We use photon differentials to determine the size and shape of the splats such that we achieve adaptive anisotropic flux density estimation in photon splatting. As compared to previous work that uses photon differentials, we present the first method...... where no photons or beams or differentials need to be stored in a map. We also present improvements in the theory of photon differentials, which give more accurate results and a faster implementation. Our technique has good potential for GPU acceleration, and we limit the number of parameters requiring...

  13. Extreme simplification and rendering of point sets using algebraic multigrid

    NARCIS (Netherlands)

    Reniers, D.; Telea, A.C.

    2009-01-01

    We present a novel approach for extreme simplification of point set models, in the context of real-time rendering. Point sets are often rendered using simple point primitives, such as oriented discs. However, this requires using many primitives to render even moderately simple shapes. Often, one

  14. How geometry and structure control the seismic radiation : spectral element simulation of the dynamic rupture of the Mw 9.0 Tohoku earthquake

    Science.gov (United States)

    Festa, G.; Vilotte, J.; Scala, A.

    2012-12-01

    The M 9.0, 2011 Tohoku earthquake, along the North American-Pacific plate boundary, East of the Honshu Island, yielded a complex broadband rupture extending southwards over 600 km along strike and triggering a large tsunami that ravaged the East coast of North Japan. Strong motion and high-rate continuous GPS data, recorded all along the Japanese archipelago by the national seismic networks K-Net and Kik-net and geodetic network Geonet, together with teleseismic data, indicated a complex frequency dependent rupture. Low frequency signals (fmeters), extending along-dip over about 100 km, between the hypocenter and the trench, and 150 to 200 km along strike. This slip asperity was likely the cause of the localized tsunami source and of the large amplitude tsunami waves. High-frequency signals (f>0.5 Hz) were instead generated close to the coast in the deeper part of the subduction zone, by at least four smaller size asperities, with possible repeated slip, and were mostly the cause for the ground shaking felt in the Eastern part of Japan. The deep origin of the high-frequency radiation was also confirmed by teleseismic high frequency back projection analysis. Intermediate frequency analysis showed a transition between the shallow and deeper part of the fault, with the rupture almost confined in a small stripe containing the hypocenter before propagating southward along the strike, indicating a predominant in-plane rupture mechanism in the initial stage of the rupture itself. We numerically investigate the role of the geometry of the subduction interface and of the structural properties of the subduction zone on the broadband dynamic rupture and radiation of the Tohoku earthquake. Based upon the almost in-plane behavior of the rupture in its initial stage, 2D non-smooth spectral element dynamic simulations of the earthquake rupture propagation are performed including the non planar and kink geometry of the subduction interface, together with bi-material interfaces

  15. Estimation of spectral kurtosis

    Science.gov (United States)

    Sutawanir

    2017-03-01

    Rolling bearings are the most important elements in rotating machinery. Bearing frequently fall out of service for various reasons: heavy loads, unsuitable lubrications, ineffective sealing. Bearing faults may cause a decrease in performance. Analysis of bearing vibration signals has attracted attention in the field of monitoring and fault diagnosis. Bearing vibration signals give rich information for early detection of bearing failures. Spectral kurtosis, SK, is a parameter in frequency domain indicating how the impulsiveness of a signal varies with frequency. Faults in rolling bearings give rise to a series of short impulse responses as the rolling elements strike faults, SK potentially useful for determining frequency bands dominated by bearing fault signals. SK can provide a measure of the distance of the analyzed bearings from a healthy one. SK provides additional information given by the power spectral density (psd). This paper aims to explore the estimation of spectral kurtosis using short time Fourier transform known as spectrogram. The estimation of SK is similar to the estimation of psd. The estimation falls in model-free estimation and plug-in estimator. Some numerical studies using simulations are discussed to support the methodology. Spectral kurtosis of some stationary signals are analytically obtained and used in simulation study. Kurtosis of time domain has been a popular tool for detecting non-normality. Spectral kurtosis is an extension of kurtosis in frequency domain. The relationship between time domain and frequency domain analysis is establish through power spectrum-autocovariance Fourier transform. Fourier transform is the main tool for estimation in frequency domain. The power spectral density is estimated through periodogram. In this paper, the short time Fourier transform of the spectral kurtosis is reviewed, a bearing fault (inner ring and outer ring) is simulated. The bearing response, power spectrum, and spectral kurtosis are plotted to

  16. TransCut: interactive rendering of translucent cutouts.

    Science.gov (United States)

    Li, Dongping; Sun, Xin; Ren, Zhong; Lin, Stephen; Tong, Yiying; Guo, Baining; Zhou, Kun

    2013-03-01

    We present TransCut, a technique for interactive rendering of translucent objects undergoing fracturing and cutting operations. As the object is fractured or cut open, the user can directly examine and intuitively understand the complex translucent interior, as well as edit material properties through painting on cross sections and recombining the broken pieces—all with immediate and realistic visual feedback. This new mode of interaction with translucent volumes is made possible with two technical contributions. The first is a novel solver for the diffusion equation (DE) over a tetrahedral mesh that produces high-quality results comparable to the state-of-art finite element method (FEM) of Arbree et al. but at substantially higher speeds. This accuracy and efficiency is obtained by computing the discrete divergences of the diffusion equation and constructing the DE matrix using analytic formulas derived for linear finite elements. The second contribution is a multiresolution algorithm to significantly accelerate our DE solver while adapting to the frequent changes in topological structure of dynamic objects. The entire multiresolution DE solver is highly parallel and easily implemented on the GPU. We believe TransCut provides a novel visual effect for heterogeneous translucent objects undergoing fracturing and cutting operations.

  17. Simple Coatings to Render Polystyrene Protein Resistant

    Directory of Open Access Journals (Sweden)

    Marcelle Hecker

    2018-02-01

    Full Text Available Non-specific protein adsorption is detrimental to the performance of many biomedical devices. Polystyrene is a commonly used material in devices and thin films. Simple reliable surface modification of polystyrene to render it protein resistant is desired in particular for device fabrication and orthogonal functionalisation schemes. This report details modifications carried out on a polystyrene surface to prevent protein adsorption. The trialed surfaces included Pluronic F127 and PLL-g-PEG, adsorbed on polystyrene, using a polydopamine-assisted approach. Quartz crystal microbalance with dissipation (QCM-D results showed only short-term anti-fouling success of the polystyrene surface modified with F127, and the subsequent failure of the polydopamine intermediary layer in improving its stability. In stark contrast, QCM-D analysis proved the success of the polydopamine assisted PLL-g-PEG coating in preventing bovine serum albumin adsorption. This modified surface is equally as protein-rejecting after 24 h in buffer, and thus a promising simple coating for long term protein rejection of polystyrene.

  18. Lighting design for globally illuminated volume rendering.

    Science.gov (United States)

    Zhang, Yubo; Ma, Kwan-Liu

    2013-12-01

    With the evolution of graphics hardware, high quality global illumination becomes available for real-time volume rendering. Compared to local illumination, global illumination can produce realistic shading effects which are closer to real world scenes, and has proven useful for enhancing volume data visualization to enable better depth and shape perception. However, setting up optimal lighting could be a nontrivial task for average users. There were lighting design works for volume visualization but they did not consider global light transportation. In this paper, we present a lighting design method for volume visualization employing global illumination. The resulting system takes into account view and transfer-function dependent content of the volume data to automatically generate an optimized three-point lighting environment. Our method fully exploits the back light which is not used by previous volume visualization systems. By also including global shadow and multiple scattering, our lighting system can effectively enhance the depth and shape perception of volumetric features of interest. In addition, we propose an automatic tone mapping operator which recovers visual details from overexposed areas while maintaining sufficient contrast in the dark areas. We show that our method is effective for visualizing volume datasets with complex structures. The structural information is more clearly and correctly presented under the automatically generated light sources.

  19. Hybrid rendering of the chest and virtual bronchoscopy [corrected].

    Science.gov (United States)

    Seemann, M D; Seemann, O; Luboldt, W; Gebicke, K; Prime, G; Claussen, C D

    2000-10-30

    Thin-section spiral computed tomography was used to acquire the volume data sets of the thorax. The tracheobronchial system and pathological changes of the chest were visualized using a color-coded surface rendering method. The structures of interest were then superimposed on a volume rendering of the other thoracic structures, thus producing a hybrid rendering. The hybrid rendering technique exploit the advantages of both rendering methods and enable virtual bronchoscopic examinations using different representation models. Virtual bronchoscopic examinations with a transparent color-coded shaded-surface model enables the simultaneous visualization of both the airways and the adjacent structures behind of the tracheobronchial wall and therefore, offers a practical alternative to fiberoptic bronchoscopy. Hybrid rendering and virtual endoscopy obviate the need for time consuming detailed analysis and presentation of axial source images.

  20. Innovative Lime Pozzolana Renders for Reconstruction of Historical Buildings

    International Nuclear Information System (INIS)

    Vejmelkova, E.; Maca, P.; Konvalinka, P.; Cerny, R.

    2011-01-01

    Bulk density, matrix density, open porosity, compressive strength, bending strength, water sorptivity, moisture diffusivity, water vapor diffusion coefficient, thermal conductivity, specific heat capacity and thermal diffusivity of two innovative renovation renders on limepozzolana basis are analyzed. The obtained results are compared with reference lime plaster and two commercial renovation renders, and conclusions on the applicability of the particular renders in practical reconstruction works are drawn. (author)

  1. Fast algorithm for the rendering of three-dimensional surfaces

    Science.gov (United States)

    Pritt, Mark D.

    1994-02-01

    It is often desirable to draw a detailed and realistic representation of surface data on a computer graphics display. One such representation is a 3D shaded surface. Conventional techniques for rendering shaded surfaces are slow, however, and require substantial computational power. Furthermore, many techniques suffer from aliasing effects, which appear as jagged lines and edges. This paper describes an algorithm for the fast rendering of shaded surfaces without aliasing effects. It is much faster than conventional ray tracing and polygon-based rendering techniques and is suitable for interactive use. On an IBM RISC System/6000TM workstation it renders a 1000 X 1000 surface in about 7 seconds.

  2. On the way to unveiling the atomic structure of superheavy elements

    International Nuclear Information System (INIS)

    Laatiaoui, Mustapha

    2016-01-01

    Optical spectroscopy of the transfermium elements (atomic number Z > 100) is nowadays one of the most fascinating and simultaneously challenging tasks in atomic physics. On the one hand, key atomic and even nuclear ground-state properties may be obtained by studying the spectral lines of these heaviest elements. On the other hand, these elements have to be produced “online” by heavy-ion induced fusion-evaporation reactions yielding rates on the order of a few atoms per second at most, which renders their optical spectroscopy extremely difficult. Only recently, a first foray of laser spectroscopy into this heaviest element region was reported. Several atomic transitions in the element nobelium (Z = 102) were observed and characterized, using an ultra-sensitive and highly efficient resonance ionization technique. The findings confirm the predictions and additionally provide a benchmark for theoretical modelling. The work represents an important stepping stone towards experimental studies of the atomic structure of superheavy elements.

  3. Moisture Transfer through Facades Covered with Organic Binder Renders

    Directory of Open Access Journals (Sweden)

    Carmen DICO

    2013-07-01

    Full Text Available Year after year we witness the negative effect of water over buildings, caused by direct or indirect actions. This situation is obvious in case of old, historical building, subjected to this aggression for a long period of time, but new buildings are also affected. Moisture in building materials causes not only structural damage, but also reduces the thermal insulation capacity of building components.Materials like plasters or paints have been used historically for a long period of time, fulfilling two basics functions: Decoration and Protection. The most acute demands are made on exterior plasters, as they, besides being an important decorative element for the facade, must perform two different functions simultaneously: protect the substrate against weathering and moisture without sealing, providing it a certain ability to “breathe” (Heilen, 2005. In order to accomplish this aim, the first step is to understand the hygrothermal behavior of coating and substrate and define the fundamental principles of moisture transfer; According to Künzel’s Facade Protection Theory, two material properties play the most important role: Water absorption and Vapor permeability.In the context of recently adoption (2009 of the “harmonized” European standard EN 15824 – „Specifications for external renders and internal plasters based on organic binders”, this paper deals extensively with the interaction of the two mentioned above properties for the coating materials, covered by EN 15824.

  4. Real-time photorealistic stereoscopic rendering of fire

    Science.gov (United States)

    Rose, Benjamin M.; McAllister, David F.

    2007-02-01

    We propose a method for real-time photorealistic stereo rendering of the natural phenomenon of fire. Applications include the use of virtual reality in fire fighting, military training, and entertainment. Rendering fire in real-time presents a challenge because of the transparency and non-static fluid-like behavior of fire. It is well known that, in general, methods that are effective for monoscopic rendering are not necessarily easily extended to stereo rendering because monoscopic methods often do not provide the depth information necessary to produce the parallax required for binocular disparity in stereoscopic rendering. We investigate the existing techniques used for monoscopic rendering of fire and discuss their suitability for extension to real-time stereo rendering. Methods include the use of precomputed textures, dynamic generation of textures, and rendering models resulting from the approximation of solutions of fluid dynamics equations through the use of ray-tracing algorithms. We have found that in order to attain real-time frame rates, our method based on billboarding is effective. Slicing is used to simulate depth. Texture mapping or 2D images are mapped onto polygons and alpha blending is used to treat transparency. We can use video recordings or prerendered high-quality images of fire as textures to attain photorealistic stereo.

  5. Method of producing hydrogen, and rendering a contaminated biomass inert

    Science.gov (United States)

    Bingham, Dennis N [Idaho Falls, ID; Klingler, Kerry M [Idaho Falls, ID; Wilding, Bruce M [Idaho Falls, ID

    2010-02-23

    A method for rendering a contaminated biomass inert includes providing a first composition, providing a second composition, reacting the first and second compositions together to form an alkaline hydroxide, providing a contaminated biomass feedstock and reacting the alkaline hydroxide with the contaminated biomass feedstock to render the contaminated biomass feedstock inert and further producing hydrogen gas, and a byproduct that includes the first composition.

  6. Realistic Real-Time Outdoor Rendering in Augmented Reality

    Science.gov (United States)

    Kolivand, Hoshang; Sunar, Mohd Shahrizal

    2014-01-01

    Realistic rendering techniques of outdoor Augmented Reality (AR) has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps). Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems. PMID:25268480

  7. Extreme Simplification and Rendering of Point Sets using Algebraic Multigrid

    NARCIS (Netherlands)

    Reniers, Dennie; Telea, Alexandru

    2005-01-01

    We present a novel approach for extreme simplification of point set models in the context of real-time rendering. Point sets are often rendered using simple point primitives, such as oriented discs. However efficient, simple primitives are less effective in approximating large surface areas. A large

  8. Transform coding for hardware-accelerated volume rendering.

    Science.gov (United States)

    Fout, Nathaniel; Ma, Kwan-Liu

    2007-01-01

    Hardware-accelerated volume rendering using the GPU is now the standard approach for real-time volume rendering, although limited graphics memory can present a problem when rendering large volume data sets. Volumetric compression in which the decompression is coupled to rendering has been shown to be an effective solution to this problem; however, most existing techniques were developed in the context of software volume rendering, and all but the simplest approaches are prohibitive in a real-time hardware-accelerated volume rendering context. In this paper we present a novel block-based transform coding scheme designed specifically with real-time volume rendering in mind, such that the decompression is fast without sacrificing compression quality. This is made possible by consolidating the inverse transform with dequantization in such a way as to allow most of the reprojection to be precomputed. Furthermore, we take advantage of the freedom afforded by off-line compression in order to optimize the encoding as much as possible while hiding this complexity from the decoder. In this context we develop a new block classification scheme which allows us to preserve perceptually important features in the compression. The result of this work is an asymmetric transform coding scheme that allows very large volumes to be compressed and then decompressed in real-time while rendering on the GPU.

  9. Light Field Rendering for Head Mounted Displays using Pixel Reprojection

    DEFF Research Database (Denmark)

    Hansen, Anne Juhler; Klein, Jákup; Kraus, Martin

    2017-01-01

    Light field displays have advantages over traditional stereoscopic head mounted displays, for example, because they can overcome the vergence-accommodation conflict. However, rendering light fields can be a heavy task for computers due to the number of images that have to be rendered. Since much ...

  10. Realistic real-time outdoor rendering in augmented reality.

    Directory of Open Access Journals (Sweden)

    Hoshang Kolivand

    Full Text Available Realistic rendering techniques of outdoor Augmented Reality (AR has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps. Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems.

  11. Media Presentation Synchronisation for Non-monolithic Rendering Architectures

    NARCIS (Netherlands)

    I. Vaishnavi (Ishan); D.C.A. Bulterman (Dick); P.S. Cesar Garcia (Pablo Santiago); B. Gao (Bo)

    2007-01-01

    htmlabstractNon-monolithic renderers are physically distributed media playback engines. Non-monolithic renderers may use a number of different underlying network connection types to transmit media items belonging to a presentation. There is therefore a need for a media based and inter-network- type

  12. Evaluating progressive-rendering algorithms in appearance design tasks.

    Science.gov (United States)

    Jiawei Ou; Karlik, Ondrej; Křivánek, Jaroslav; Pellacini, Fabio

    2013-01-01

    Progressive rendering is becoming a popular alternative to precomputational approaches to appearance design. However, progressive algorithms create images exhibiting visual artifacts at early stages. A user study investigated these artifacts' effects on user performance in appearance design tasks. Novice and expert subjects performed lighting and material editing tasks with four algorithms: random path tracing, quasirandom path tracing, progressive photon mapping, and virtual-point-light rendering. Both the novices and experts strongly preferred path tracing to progressive photon mapping and virtual-point-light rendering. None of the participants preferred random path tracing to quasirandom path tracing or vice versa; the same situation held between progressive photon mapping and virtual-point-light rendering. The user workflow didn’t differ significantly with the four algorithms. The Web Extras include a video showing how four progressive-rendering algorithms converged (at http://youtu.be/ck-Gevl1e9s), the source code used, and other supplementary materials.

  13. Spectral stratigraphy

    Science.gov (United States)

    Lang, Harold R.

    1991-01-01

    A new approach to stratigraphic analysis is described which uses photogeologic and spectral interpretation of multispectral remote sensing data combined with topographic information to determine the attitude, thickness, and lithology of strata exposed at the surface. The new stratigraphic procedure is illustrated by examples in the literature. The published results demonstrate the potential of spectral stratigraphy for mapping strata, determining dip and strike, measuring and correlating stratigraphic sequences, defining lithofacies, mapping biofacies, and interpreting geological structures.

  14. Influence of 'third' elements and structure on the results of spectral analysis of high alloyed steels and cast iron with glow discharge

    International Nuclear Information System (INIS)

    Buravlev, Yu.M.; Zamarajev, V.P.; Chernyavskaya, N.V.

    1989-01-01

    The experimental technique consists in estimation of mutual arrangement of the calibration curves obtained using standard reference materials of low-alloyed and high-alloyed (high-chrome, stainless, high-speed) steels as well as of the curves for carbon steels and cast iron differing in their structure. ARL-31000 and Polyvac E-1000 quantometers with U=1300 V, I=0.12 A and argon pressure ∼1 kPa are used. The influence of third elements is shown in shift and slope changes of the curves for abovementioned high-alloyed steels in comparison to ones for low-alloyed steels accepted as basic. The influence magnitude runs up to 10-30 relative percents and more in the case of analysis of carbon, phosphorus, sulfur, silicon and other elements and depends on the type of the element and on the alloy composition. It is shown that the contribution of structure factor caused by different alloy thermal treatment makes up 10 to 20 relative percents. The experiments showed that the increase of influence of these factors caused by their imposing as well as the weakening of this influence caused by their counteraction is possible. When analyzed alloys differ in their composition and manufacturing technology it is necessary to take into consideration the influence of these effects. (author)

  15. Photovoltaic spectral responsivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Dunlavy, D.; Field, H.; Moriarty, T. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper discusses the various elemental random and nonrandom error sources in typical spectral responsivity measurement systems. The authors focus specifically on the filter and grating monochrometer-based spectral responsivity measurement systems used by the Photovoltaic (PV) performance characterization team at NREL. A variety of subtle measurement errors can occur that arise from a finite photo-current response time, bandwidth of the monochromatic light, waveform of the monochromatic light, and spatial uniformity of the monochromatic and bias lights; the errors depend on the light source, PV technology, and measurement system. The quantum efficiency can be a function of he voltage bias, light bias level, and, for some structures, the spectral content of the bias light or location on the PV device. This paper compares the advantages and problems associated with semiconductor-detector-based calibrations and pyroelectric-detector-based calibrations. Different current-to-voltage conversion and ac photo-current detection strategies employed at NREL are compared and contrasted.

  16. Light Field Rendering for Head Mounted Displays using Pixel Reprojection

    DEFF Research Database (Denmark)

    Hansen, Anne Juhler; Klein, Jákup; Kraus, Martin

    2017-01-01

    of the information of the different images is redundant, we use pixel reprojection from the corner cameras to compute the remaining images in the light field. We compare the reprojected images with directly rendered images in a user test. In most cases, the users were unable to distinguish the images. In extreme...... cases, the reprojection approach is not capable of creating the light field. We conclude that pixel reprojection is a feasible method for rendering light fields as far as quality of perspective and diffuse shading is concerned, but render time needs to be reduced to make the method practical....

  17. On spectral pollution

    International Nuclear Information System (INIS)

    Llobet, X.; Appert, K.; Bondeson, A.; Vaclavik, J.

    1990-01-01

    Finite difference and finite element approximations of eigenvalue problems, under certain circumstances exhibit spectral pollution, i.e. the appearance of eigenvalues that do not converge to the correct value when the mesh density is increased. In the present paper this phenomenon is investigated in a homogeneous case by means of discrete dispersion relations: the polluting modes belong to a branch of the dispersion relation that is strongly distorted by the discretization method employed, or to a new, spurious branch. The analysis is applied to finite difference methods and to finite element methods, and some indications about how to avoiding polluting schemes are given. (author) 5 figs., 10 refs

  18. Spectral shift reactor

    International Nuclear Information System (INIS)

    Carlson, W.R.; Piplica, E.J.

    1982-01-01

    A spectral shift pressurized water reactor comprising apparatus for inserting and withdrawing water displacer elements having differing neutron absorbing capabilities for selectively changing the water-moderator volume in the core thereby changing the reactivity of the core. The displacer elements comprise substantially hollow cylindrical low neutron absorbing rods and substantially hollow cylindrical thick walled stainless rods. Since the stainless steel displacer rods have greater neutron absorbing capability, they can effect greater reactivity change per rod. However, by arranging fewer stainless steel displacer rods in a cluster, the reactivity worth of the stainless steel displacer rod cluster can be less than a low neutron absorbing displacer rod cluster. (author)

  19. View compensated compression of volume rendered images for remote visualization.

    Science.gov (United States)

    Lalgudi, Hariharan G; Marcellin, Michael W; Bilgin, Ali; Oh, Han; Nadar, Mariappan S

    2009-07-01

    Remote visualization of volumetric images has gained importance over the past few years in medical and industrial applications. Volume visualization is a computationally intensive process, often requiring hardware acceleration to achieve a real time viewing experience. One remote visualization model that can accomplish this would transmit rendered images from a server, based on viewpoint requests from a client. For constrained server-client bandwidth, an efficient compression scheme is vital for transmitting high quality rendered images. In this paper, we present a new view compensation scheme that utilizes the geometric relationship between viewpoints to exploit the correlation between successive rendered images. The proposed method obviates motion estimation between rendered images, enabling significant reduction to the complexity of a compressor. Additionally, the view compensation scheme, in conjunction with JPEG2000 performs better than AVC, the state of the art video compression standard.

  20. Factors affecting extension workers in their rendering of effective ...

    African Journals Online (AJOL)

    Factors affecting extension workers in their rendering of effective service to pre and ... Small, micro and medium entrepreneurs play an important role in economic ... such as production, marketing and management to adequately service the ...

  1. Sparse PDF Volumes for Consistent Multi-Resolution Volume Rendering

    KAUST Repository

    Sicat, Ronell Barrera; Kruger, Jens; Moller, Torsten; Hadwiger, Markus

    2014-01-01

    This paper presents a new multi-resolution volume representation called sparse pdf volumes, which enables consistent multi-resolution volume rendering based on probability density functions (pdfs) of voxel neighborhoods. These pdfs are defined

  2. Experiencing "Macbeth": From Text Rendering to Multicultural Performance.

    Science.gov (United States)

    Reisin, Gail

    1993-01-01

    Shows how one teacher used innovative methods in teaching William Shakespeare's "Macbeth." Outlines student assignments including text renderings, rewriting a scene from the play, and creating a multicultural scrapbook for the play. (HB)

  3. Insurance of professional responsibility at medical aid rendering

    Directory of Open Access Journals (Sweden)

    Abyzova N.V.

    2011-12-01

    Full Text Available The article discusses the necessity of adoption of professional responsibility insurance act into the public health service. It is considered as the basic mechanism of compensation in case of damage to a patient at medical aid rendering

  4. Beaming teaching application: recording techniques for spatial xylophone sound rendering

    DEFF Research Database (Denmark)

    Markovic, Milos; Madsen, Esben; Olesen, Søren Krarup

    2012-01-01

    BEAMING is a telepresence research project aiming at providing a multimodal interaction between two or more participants located at distant locations. One of the BEAMING applications allows a distant teacher to give a xylophone playing lecture to the students. Therefore, rendering of the xylophon...... to spatial improvements mainly in terms of the Apparent Source Width (ASW). Rendered examples are subjectively evaluated in listening tests by comparing them with binaural recording....

  5. Anisotropic 3D texture synthesis with application to volume rendering

    DEFF Research Database (Denmark)

    Laursen, Lasse Farnung; Ersbøll, Bjarne Kjær; Bærentzen, Jakob Andreas

    2011-01-01

    images using a 12.1 megapixel camera. Next, we extend the volume rendering pipeline by creating a transfer function which yields not only color and opacity from the input intensity, but also texture coordinates for our synthesized 3D texture. Thus, we add texture to the volume rendered images....... This method is applied to a high quality visualization of a pig carcass, where samples of meat, bone, and fat have been used to produce the anisotropic 3D textures....

  6. Graphical User Interfaces for Volume Rendering Applications in Medical Imaging

    OpenAIRE

    Lindfors, Lisa; Lindmark, Hanna

    2002-01-01

    Volume rendering applications are used in medical imaging in order to facilitate the analysis of three-dimensional image data. This study focuses on how to improve the usability of graphical user interfaces of these systems, by gathering user requirements. This is achieved by evaluations of existing systems, together with interviews and observations at clinics in Sweden that use volume rendering to some extent. The usability of the applications of today is not sufficient, according to the use...

  7. A Sort-Last Rendering System over an Optical Backplane

    Directory of Open Access Journals (Sweden)

    Yasuhiro Kirihata

    2005-06-01

    Full Text Available Sort-Last is a computer graphics technique for rendering extremely large data sets on clusters of computers. Sort-Last works by dividing the data set into even-sized chunks for parallel rendering and then composing the images to form the final result. Since sort-last rendering requires the movement of large amounts of image data among cluster nodes, the network interconnecting the nodes becomes a major bottleneck. In this paper, we describe a sort-last rendering system implemented on a cluster of computers whose nodes are connected by an all-optical switch. The rendering system introduces the notion of the Photonic Computing Engine, a computing system built dynamically by using the optical switch to create dedicated network connections among cluster nodes. The sort-last volume rendering algorithm was implemented on the Photonic Computing Engine, and its performance is evaluated. Prelimi- nary experiments show that performance is affected by the image composition time and average payload size. In an attempt to stabilize the performance of the system, we have designed a flow control mechanism that uses feedback messages to dynamically adjust the data flow rate within the computing engine.

  8. Fast DRR splat rendering using common consumer graphics hardware

    International Nuclear Information System (INIS)

    Spoerk, Jakob; Bergmann, Helmar; Wanschitz, Felix; Dong, Shuo; Birkfellner, Wolfgang

    2007-01-01

    Digitally rendered radiographs (DRR) are a vital part of various medical image processing applications such as 2D/3D registration for patient pose determination in image-guided radiotherapy procedures. This paper presents a technique to accelerate DRR creation by using conventional graphics hardware for the rendering process. DRR computation itself is done by an efficient volume rendering method named wobbled splatting. For programming the graphics hardware, NVIDIAs C for Graphics (Cg) is used. The description of an algorithm used for rendering DRRs on the graphics hardware is presented, together with a benchmark comparing this technique to a CPU-based wobbled splatting program. Results show a reduction of rendering time by about 70%-90% depending on the amount of data. For instance, rendering a volume of 2x10 6 voxels is feasible at an update rate of 38 Hz compared to 6 Hz on a common Intel-based PC using the graphics processing unit (GPU) of a conventional graphics adapter. In addition, wobbled splatting using graphics hardware for DRR computation provides higher resolution DRRs with comparable image quality due to special processing characteristics of the GPU. We conclude that DRR generation on common graphics hardware using the freely available Cg environment is a major step toward 2D/3D registration in clinical routine

  9. Remote volume rendering pipeline for mHealth applications

    Science.gov (United States)

    Gutenko, Ievgeniia; Petkov, Kaloian; Papadopoulos, Charilaos; Zhao, Xin; Park, Ji Hwan; Kaufman, Arie; Cha, Ronald

    2014-03-01

    We introduce a novel remote volume rendering pipeline for medical visualization targeted for mHealth (mobile health) applications. The necessity of such a pipeline stems from the large size of the medical imaging data produced by current CT and MRI scanners with respect to the complexity of the volumetric rendering algorithms. For example, the resolution of typical CT Angiography (CTA) data easily reaches 512^3 voxels and can exceed 6 gigabytes in size by spanning over the time domain while capturing a beating heart. This explosion in data size makes data transfers to mobile devices challenging, and even when the transfer problem is resolved the rendering performance of the device still remains a bottleneck. To deal with this issue, we propose a thin-client architecture, where the entirety of the data resides on a remote server where the image is rendered and then streamed to the client mobile device. We utilize the display and interaction capabilities of the mobile device, while performing interactive volume rendering on a server capable of handling large datasets. Specifically, upon user interaction the volume is rendered on the server and encoded into an H.264 video stream. H.264 is ubiquitously hardware accelerated, resulting in faster compression and lower power requirements. The choice of low-latency CPU- and GPU-based encoders is particularly important in enabling the interactive nature of our system. We demonstrate a prototype of our framework using various medical datasets on commodity tablet devices.

  10. RenderSelect: a Cloud Broker Framework for Cloud Renderfarm Services

    OpenAIRE

    Ruby, Annette J; Aisha, Banu W; Subash, Chandran P

    2016-01-01

    In the 3D studios the animation scene files undergo a process called as rendering, where the 3D wire frame models are converted into 3D photorealistic images. As the rendering process is both a computationally intensive and a time consuming task, the cloud services based rendering in cloud render farms is gaining popularity among the animators. Though cloud render farms offer many benefits, the animators hesitate to move from their traditional offline rendering to cloud services based render ...

  11. Architecture for high performance stereoscopic game rendering on Android

    Science.gov (United States)

    Flack, Julien; Sanderson, Hugh; Shetty, Sampath

    2014-03-01

    Stereoscopic gaming is a popular source of content for consumer 3D display systems. There has been a significant shift in the gaming industry towards casual games for mobile devices running on the Android™ Operating System and driven by ARM™ and other low power processors. Such systems are now being integrated directly into the next generation of 3D TVs potentially removing the requirement for an external games console. Although native stereo support has been integrated into some high profile titles on established platforms like Windows PC and PS3 there is a lack of GPU independent 3D support for the emerging Android platform. We describe a framework for enabling stereoscopic 3D gaming on Android for applications on mobile devices, set top boxes and TVs. A core component of the architecture is a 3D game driver, which is integrated into the Android OpenGL™ ES graphics stack to convert existing 2D graphics applications into stereoscopic 3D in real-time. The architecture includes a method of analyzing 2D games and using rule based Artificial Intelligence (AI) to position separate objects in 3D space. We describe an innovative stereo 3D rendering technique to separate the views in the depth domain and render directly into the display buffer. The advantages of the stereo renderer are demonstrated by characterizing the performance in comparison to more traditional render techniques, including depth based image rendering, both in terms of frame rates and impact on battery consumption.

  12. Volume rendering in treatment planning for moving targets

    Energy Technology Data Exchange (ETDEWEB)

    Gemmel, Alexander [GSI-Biophysics, Darmstadt (Germany); Massachusetts General Hospital, Boston (United States); Wolfgang, John A.; Chen, George T.Y. [Massachusetts General Hospital, Boston (United States)

    2009-07-01

    Advances in computer technologies have facilitated the development of tools for 3-dimensional visualization of CT-data sets with volume rendering. The company Fovia has introduced a high definition volume rendering engine (HDVR trademark by Fovia Inc., Palo Alto, USA) that is capable of representing large CT data sets with high user interactivity even on standard PCs. Fovia provides a software development kit (SDK) that offers control of all the features of the rendering engine. We extended the SDK by functionalities specific to the task of treatment planning for moving tumors. This included navigation of the patient's anatomy in beam's eye view, fast point-and-click measurement of lung tumor trajectories as well as estimation of range perturbations due to motion by calculation of (differential) water equivalent path lengths for protons and carbon ions on 4D-CT data sets. We present patient examples to demonstrate the advantages and disadvantages of volume rendered images as compared to standard 2-dimensional axial plane images. Furthermore, we show an example of a range perturbation analysis. We conclude that volume rendering is a powerful technique for the representation and analysis of large time resolved data sets in treatment planning.

  13. A kinesthetic washout filter for force-feedback rendering.

    Science.gov (United States)

    Danieau, Fabien; Lecuyer, Anatole; Guillotel, Philippe; Fleureau, Julien; Mollet, Nicolas; Christie, Marc

    2015-01-01

    Today haptic feedback can be designed and associated to audiovisual content (haptic-audiovisuals or HAV). Although there are multiple means to create individual haptic effects, the issue of how to properly adapt such effects on force-feedback devices has not been addressed and is mostly a manual endeavor. We propose a new approach for the haptic rendering of HAV, based on a washout filter for force-feedback devices. A body model and an inverse kinematics algorithm simulate the user's kinesthetic perception. Then, the haptic rendering is adapted in order to handle transitions between haptic effects and to optimize the amplitude of effects regarding the device capabilities. Results of a user study show that this new haptic rendering can successfully improve the HAV experience.

  14. Clustered deep shadow maps for integrated polyhedral and volume rendering

    KAUST Repository

    Bornik, Alexander

    2012-01-01

    This paper presents a hardware-accelerated approach for shadow computation in scenes containing both complex volumetric objects and polyhedral models. Our system is the first hardware accelerated complete implementation of deep shadow maps, which unifies the computation of volumetric and geometric shadows. Up to now such unified computation was limited to software-only rendering . Previous hardware accelerated techniques can handle only geometric or only volumetric scenes - both resulting in the loss of important properties of the original concept. Our approach supports interactive rendering of polyhedrally bounded volumetric objects on the GPU based on ray casting. The ray casting can be conveniently used for both the shadow map computation and the rendering. We show how anti-aliased high-quality shadows are feasible in scenes composed of multiple overlapping translucent objects, and how sparse scenes can be handled efficiently using clustered deep shadow maps. © 2012 Springer-Verlag.

  15. Mucosal detail at CT virtual reality: surface versus volume rendering.

    Science.gov (United States)

    Hopper, K D; Iyriboz, A T; Wise, S W; Neuman, J D; Mauger, D T; Kasales, C J

    2000-02-01

    To evaluate computed tomographic virtual reality with volumetric versus surface rendering. Virtual reality images were reconstructed for 27 normal or pathologic colonic, gastric, or bronchial structures in four ways: the transition zone (a) reconstructed separately from the wall by using volume rendering; (b) with attenuation equal to air; (c) with attenuation equal to wall (soft tissue); (d) with attenuation halfway between air and wall. The four reconstructed images were randomized. Four experienced imagers blinded to the reconstruction graded them from best to worst with predetermined criteria. All readers rated images with the transition zone as a separate structure as overwhelmingly superior (P Virtual reality is best with volume rendering, with the transition zone (mucosa) between the wall and air reconstructed as a separate structure.

  16. Depth of Field Effects for Interactive Direct Volume Rendering

    KAUST Repository

    Schott, Mathias; Pascal Grosset, A.V.; Martin, Tobias; Pegoraro, Vincent; Smith, Sean T.; Hansen, Charles D.

    2011-01-01

    In this paper, a method for interactive direct volume rendering is proposed for computing depth of field effects, which previously were shown to aid observers in depth and size perception of synthetically generated images. The presented technique extends those benefits to volume rendering visualizations of 3D scalar fields from CT/MRI scanners or numerical simulations. It is based on incremental filtering and as such does not depend on any precomputation, thus allowing interactive explorations of volumetric data sets via on-the-fly editing of the shading model parameters or (multi-dimensional) transfer functions. © 2011 The Author(s).

  17. Depth of Field Effects for Interactive Direct Volume Rendering

    KAUST Repository

    Schott, Mathias

    2011-06-01

    In this paper, a method for interactive direct volume rendering is proposed for computing depth of field effects, which previously were shown to aid observers in depth and size perception of synthetically generated images. The presented technique extends those benefits to volume rendering visualizations of 3D scalar fields from CT/MRI scanners or numerical simulations. It is based on incremental filtering and as such does not depend on any precomputation, thus allowing interactive explorations of volumetric data sets via on-the-fly editing of the shading model parameters or (multi-dimensional) transfer functions. © 2011 The Author(s).

  18. Chromium Renderserver: Scalable and Open Source Remote RenderingInfrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Brian; Ahern, Sean; Bethel, E. Wes; Brugger, Eric; Cook,Rich; Daniel, Jamison; Lewis, Ken; Owen, Jens; Southard, Dale

    2007-12-01

    Chromium Renderserver (CRRS) is software infrastructure thatprovides the ability for one or more users to run and view image outputfrom unmodified, interactive OpenGL and X11 applications on a remote,parallel computational platform equipped with graphics hardwareaccelerators via industry-standard Layer 7 network protocolsand clientviewers. The new contributions of this work include a solution to theproblem of synchronizing X11 and OpenGL command streams, remote deliveryof parallel hardware-accelerated rendering, and a performance analysis ofseveral different optimizations that are generally applicable to avariety of rendering architectures. CRRSis fully operational, Open Sourcesoftware.

  19. The matrix effect study in the spectrographic analysis of rare earth elements. Pt. 1. The influence of Sn, Pb, Sb, Bi, Cu, Ag, Zn and Cd on the spectral lines intensity of Y, La, Ce, Pr, Nd and Sm in the current arc exciting between C-electrodes

    International Nuclear Information System (INIS)

    Wysocka-Lisek, J.; Paszkowska, B.; Mularczyk, K.

    1976-01-01

    In the beginning the influence of Sn, Pb, Sb, Bi, Cu, Ag, Zn and Cd on the light rare earth spectral lines using Ni as the internal standard, during the intermittent current arc excitation between C-electrodes was studied. On the basis of the spectral lines intensity measurements, it was stated that one may apply the addition of Ni as the internal standard by the quantitative determination of Sn, Pb, Sb, Bi, Zn and Cd in the light rare earth mixtures with one of the above. Also a great influence of the presence of the individually studied metal was observed on the spectral line intensity of rare earth elements and nickel. The differences of the thermo-chemical reactions nature between excited elements and the carbon of the electrodes may cause that influence. (author)

  20. A two-metric proposal to specify the color-rendering properties of light sources for retail lighting

    Science.gov (United States)

    Freyssinier, Jean Paul; Rea, Mark

    2010-08-01

    Lighting plays an important role in supporting retail operations, from attracting customers, to enabling the evaluation of merchandise, to facilitating the completion of the sale. Lighting also contributes to the identity, comfort, and visual quality of a retail store. With the increasing availability and quality of white LEDs, retail lighting specifiers are now considering LED lighting in stores. The color rendering of light sources is a key factor in supporting retail lighting goals and thus influences a light source's acceptance by users and specifiers. However, there is limited information on what consumers' color preferences are, and metrics used to describe the color properties of light sources often are equivocal and fail to predict preference. The color rendering of light sources is described in the industry solely by the color rendering index (CRI), which is only indirectly related to human perception. CRI is intended to characterize the appearance of objects illuminated by the source and is increasingly being challenged because new sources are being developed with increasingly exotic spectral power distributions. This paper discusses how CRI might be augmented to better use it in support of the design objectives for retail merchandising. The proposed guidelines include the use of gamut area index as a complementary metric to CRI for assuring good color rendering.

  1. 7 CFR 54.1016 - Advance information concerning service rendered.

    Science.gov (United States)

    2010-01-01

    ... MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT... rendered. Upon request of any applicant, all or any part of the contents of any report issued to the...

  2. Frequency Analysis of Gradient Estimators in Volume Rendering

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Lichtenbelt, Barthold B.A.; Malzbender, Tom

    1996-01-01

    Gradient information is used in volume rendering to classify and color samples along a ray. In this paper, we present an analysis of the theoretically ideal gradient estimator and compare it to some commonly used gradient estimators. A new method is presented to calculate the gradient at arbitrary

  3. Matching rendered and real world images by digital image processing

    Science.gov (United States)

    Mitjà, Carles; Bover, Toni; Bigas, Miquel; Escofet, Jaume

    2010-05-01

    Recent advances in computer-generated images (CGI) have been used in commercial and industrial photography providing a broad scope in product advertising. Mixing real world images with those rendered from virtual space software shows a more or less visible mismatching between corresponding image quality performance. Rendered images are produced by software which quality performance is only limited by the resolution output. Real world images are taken with cameras with some amount of image degradation factors as lens residual aberrations, diffraction, sensor low pass anti aliasing filters, color pattern demosaicing, etc. The effect of all those image quality degradation factors can be characterized by the system Point Spread Function (PSF). Because the image is the convolution of the object by the system PSF, its characterization shows the amount of image degradation added to any taken picture. This work explores the use of image processing to degrade the rendered images following the parameters indicated by the real system PSF, attempting to match both virtual and real world image qualities. The system MTF is determined by the slanted edge method both in laboratory conditions and in the real picture environment in order to compare the influence of the working conditions on the device performance; an approximation to the system PSF is derived from the two measurements. The rendered images are filtered through a Gaussian filter obtained from the taking system PSF. Results with and without filtering are shown and compared measuring the contrast achieved in different final image regions.

  4. The effects of multiview depth video compression on multiview rendering

    NARCIS (Netherlands)

    Merkle, P.; Morvan, Y.; Smolic, A.; Farin, D.S.; Mueller, K.; With, de P.H.N.; Wiegang, T.

    2009-01-01

    This article investigates the interaction between different techniques for depth compression and view synthesis rendering with multiview video plus scene depth data. Two different approaches for depth coding are compared, namely H.264/MVC, using temporal and inter-view reference images for efficient

  5. The effect of depth compression on multiview rendering quality

    NARCIS (Netherlands)

    Merkle, P.; Morvan, Y.; Smolic, A.; Farin, D.S.; Mueller, K..; With, de P.H.N.; Wiegand, T.

    2010-01-01

    This paper presents a comparative study on different techniques for depth-image compression and its implications on the quality of multiview video plus depth virtual view rendering. A novel coding algorithm for depth images that concentrates on their special characteristics, namely smooth regions

  6. The Peshitta Rendering of Psalm 25: Spelling, Synonyms, and Syntax’

    NARCIS (Netherlands)

    Dyk, J.W.; Loopstra, J.; Sokoloff, M.

    2013-01-01

    The very act of making a translation implies that the rendered text will differ from the source text. The underlying presupposition is that the grammar, syntax, and semantics of the source and target languages are sufficiently divergent as to warrant a translation. Translations differ in how close

  7. Democratizing rendering for multiple viewers in surround VR systems

    KAUST Repository

    Schulze, Jürgen P.

    2012-03-01

    We present a new approach for how multiple users\\' views can be rendered in a surround virtual environment without using special multi-view hardware. It is based on the idea that different parts of the screen are often viewed by different users, so that they can be rendered from their own view point, or at least from a point closer to their view point than traditionally expected. The vast majority of 3D virtual reality systems are designed for one head-tracked user, and a number of passive viewers. Only the head tracked user gets to see the correct view of the scene, everybody else sees a distorted image. We reduce this problem by algorithmically democratizing the rendering view point among all tracked users. Researchers have proposed solutions for multiple tracked users, but most of them require major changes to the display hardware of the VR system, such as additional projectors or custom VR glasses. Our approach does not require additional hardware, except the ability to track each participating user. We propose three versions of our multi-viewer algorithm. Each of them balances image distortion and frame rate in different ways, making them more or less suitable for certain application scenarios. Our most sophisticated algorithm renders each pixel from its own, optimized camera perspective, which depends on all tracked users\\' head positions and orientations. © 2012 IEEE.

  8. Remote parallel rendering for high-resolution tiled display walls

    KAUST Repository

    Nachbaur, Daniel

    2014-11-01

    © 2014 IEEE. We present a complete, robust and simple to use hardware and software stack delivering remote parallel rendering of complex geometrical and volumetric models to high resolution tiled display walls in a production environment. We describe the setup and configuration, present preliminary benchmarks showing interactive framerates, and describe our contributions for a seamless integration of all the software components.

  9. Remote parallel rendering for high-resolution tiled display walls

    KAUST Repository

    Nachbaur, Daniel; Dumusc, Raphael; Bilgili, Ahmet; Hernando, Juan; Eilemann, Stefan

    2014-01-01

    © 2014 IEEE. We present a complete, robust and simple to use hardware and software stack delivering remote parallel rendering of complex geometrical and volumetric models to high resolution tiled display walls in a production environment. We describe the setup and configuration, present preliminary benchmarks showing interactive framerates, and describe our contributions for a seamless integration of all the software components.

  10. Democratizing rendering for multiple viewers in surround VR systems

    KAUST Repository

    Schulze, Jü rgen P.; Acevedo-Feliz, Daniel; Mangan, John; Prudhomme, Andrew; Nguyen, Phi Khanh; Weber, Philip P.

    2012-01-01

    We present a new approach for how multiple users' views can be rendered in a surround virtual environment without using special multi-view hardware. It is based on the idea that different parts of the screen are often viewed by different users, so that they can be rendered from their own view point, or at least from a point closer to their view point than traditionally expected. The vast majority of 3D virtual reality systems are designed for one head-tracked user, and a number of passive viewers. Only the head tracked user gets to see the correct view of the scene, everybody else sees a distorted image. We reduce this problem by algorithmically democratizing the rendering view point among all tracked users. Researchers have proposed solutions for multiple tracked users, but most of them require major changes to the display hardware of the VR system, such as additional projectors or custom VR glasses. Our approach does not require additional hardware, except the ability to track each participating user. We propose three versions of our multi-viewer algorithm. Each of them balances image distortion and frame rate in different ways, making them more or less suitable for certain application scenarios. Our most sophisticated algorithm renders each pixel from its own, optimized camera perspective, which depends on all tracked users' head positions and orientations. © 2012 IEEE.

  11. 3D rendering and interactive visualization technology in large industry CT

    International Nuclear Information System (INIS)

    Xiao Yongshun; Zhang Li; Chen Zhiqiang; Kang Kejun

    2001-01-01

    This paper introduces the applications of interactive 3D rendering technology in the large ICT. It summarizes and comments on the iso-surfaces rendering and the direct volume rendering methods used in ICT. The paper emphasizes on the technical analysis of the 3D rendering process of ICT volume data sets, and summarizes the difficulties of the inspection subsystem design in large ICT

  12. 3D rendering and interactive visualization technology in large industry CT

    International Nuclear Information System (INIS)

    Xiao Yongshun; Zhang Li; Chen Zhiqiang; Kang Kejun

    2002-01-01

    The author introduces the applications of interactive 3D rendering technology in the large ICT. It summarizes and comments on the iso-surfaces rendering and the direct volume rendering methods used in ICT. The author emphasizes on the technical analysis of the 3D rendering process of ICT volume data sets, and summarizes the difficulties of the inspection subsystem design in large ICT

  13. New impressive capabilities of SE-workbench for EO/IR real-time rendering of animated scenarios including flares

    Science.gov (United States)

    Le Goff, Alain; Cathala, Thierry; Latger, Jean

    2015-10-01

    To provide technical assessments of EO/IR flares and self-protection systems for aircraft, DGA Information superiority resorts to synthetic image generation to model the operational battlefield of an aircraft, as viewed by EO/IR threats. For this purpose, it completed the SE-Workbench suite from OKTAL-SE with functionalities to predict a realistic aircraft IR signature and is yet integrating the real-time EO/IR rendering engine of SE-Workbench called SE-FAST-IR. This engine is a set of physics-based software and libraries that allows preparing and visualizing a 3D scene for the EO/IR domain. It takes advantage of recent advances in GPU computing techniques. The recent past evolutions that have been performed concern mainly the realistic and physical rendering of reflections, the rendering of both radiative and thermal shadows, the use of procedural techniques for the managing and the rendering of very large terrains, the implementation of Image- Based Rendering for dynamic interpolation of plume static signatures and lastly for aircraft the dynamic interpolation of thermal states. The next step is the representation of the spectral, directional, spatial and temporal signature of flares by Lacroix Defense using OKTAL-SE technology. This representation is prepared from experimental data acquired during windblast tests and high speed track tests. It is based on particle system mechanisms to model the different components of a flare. The validation of a flare model will comprise a simulation of real trials and a comparison of simulation outputs to experimental results concerning the flare signature and above all the behavior of the stimulated threat.

  14. Water driven leaching of biocides from paints and renders

    DEFF Research Database (Denmark)

    Bester, Kai; Vollertsen, Jes; Bollmann, Ulla E

    ) were so high, that rather professional urban gardening (flower and greenhouses) than handling of biocides from construction materials seem to be able to explain the findings. While the use in agriculture is restricted, the use in greenhouses is currently considered legal in Denmark. Leaching....../partitioning: Considering material properties, it was found out that, for all of the compounds the sorption (and leaching) is highly pH-dependent. It must be take into account that the pH in the porewater of the tested render materials is between 9 and 10 while the rainwater is around 5, thus making prediction difficult...... at this stage. For some of the compounds the sorption is dependent on the amount of polymer in the render, while it is only rarely of importance which polymer is used. Considering the interaction of weather with the leaching of biocides from real walls it turned out that a lot of parameters such as irradiation...

  15. Emotion rendering in auditory simulations of imagined walking styles

    DEFF Research Database (Denmark)

    Turchet, Luca; Rodá, Antonio

    2016-01-01

    This paper investigated how different emotional states of a walker can be rendered and recognized by means of footstep sounds synthesis algorithms. In a first experiment, participants were asked to render, according to imagined walking scenarios, five emotions (aggressive, happy, neutral, sad......, and tender) by manipulating the parameters of synthetic footstep sounds simulating various combinations of surface materials and shoes types. Results allowed to identify, for the involved emotions and sound conditions, the mean values and ranges of variation of two parameters, sound level and temporal...... distance between consecutive steps. Results were in accordance with those reported in previous studies on real walking, suggesting that expression of emotions in walking is independent from the real or imagined motor activity. In a second experiment participants were asked to identify the emotions...

  16. Tactile display for virtual 3D shape rendering

    CERN Document Server

    Mansutti, Alessandro; Bordegoni, Monica; Cugini, Umberto

    2017-01-01

    This book describes a novel system for the simultaneous visual and tactile rendering of product shapes which allows designers to simultaneously touch and see new product shapes during the conceptual phase of product development. This system offers important advantages, including potential cost and time savings, compared with the standard product design process in which digital 3D models and physical prototypes are often repeatedly modified until an optimal design is achieved. The system consists of a tactile display that is able to represent, within a real environment, the shape of a product. Designers can explore the rendered surface by touching curves lying on the product shape, selecting those curves that can be considered style features and evaluating their aesthetic quality. In order to physically represent these selected curves, a flexible surface is modeled by means of servo-actuated modules controlling a physical deforming strip. The tactile display is designed so as to be portable, low cost, modular,...

  17. Hybrid fur rendering: combining volumetric fur with explicit hair strands

    DEFF Research Database (Denmark)

    Andersen, Tobias Grønbeck; Falster, Viggo; Frisvad, Jeppe Revall

    2016-01-01

    Hair is typically modeled and rendered using either explicitly defined hair strand geometry or a volume texture of hair densities. Taken each on their own, these two hair representations have difficulties in the case of animal fur as it consists of very dense and thin undercoat hairs in combination...... with coarse guard hairs. Explicit hair strand geometry is not well-suited for the undercoat hairs, while volume textures are not well-suited for the guard hairs. To efficiently model and render both guard hairs and undercoat hairs, we present a hybrid technique that combines rasterization of explicitly...... defined guard hairs with ray marching of a prismatic shell volume with dynamic resolution. The latter is the key to practical combination of the two techniques, and it also enables a high degree of detail in the undercoat. We demonstrate that our hybrid technique creates a more detailed and soft fur...

  18. Radiographic element

    International Nuclear Information System (INIS)

    Abbott, T.I.; Jones, C.G.

    1984-01-01

    Radiographic elements are disclosed comprised of first and second silver halide emulsion layers separated by an interposed support capable of transmitting radiation to which the second image portion is responsive. At least the first imaging portion contains a silver halide emulsion in which thin tubular silver halide grains of intermediate aspect ratios (from 5:1 to 8:1) are present. Spectral sensitizing dye is adsorbed to the surface of the tubular grains. Increased photographic speeds can be realized at comparable levels of crossover. (author)

  19. Spacetime Discontinuous Galerkin FEM: Spectral Response

    International Nuclear Information System (INIS)

    Abedi, R; Omidi, O; Clarke, P L

    2014-01-01

    Materials in nature demonstrate certain spectral shapes in terms of their material properties. Since successful experimental demonstrations in 2000, metamaterials have provided a means to engineer materials with desired spectral shapes for their material properties. Computational tools are employed in two different aspects for metamaterial modeling: 1. Mircoscale unit cell analysis to derive and possibly optimize material's spectral response; 2. macroscale to analyze their interaction with conventional material. We compare two different approaches of Time-Domain (TD) and Frequency Domain (FD) methods for metamaterial applications. Finally, we discuss advantages of the TD method of Spacetime Discontinuous Galerkin finite element method (FEM) for spectral analysis of metamaterials

  20. Spectral Imaging by Upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    We present a method to obtain spectrally resolved images using upconversion. By this method an image is spectrally shifted from one spectral region to another wavelength. Since the process is spectrally sensitive it allows for a tailored spectral response. We believe this will allow standard...... silicon based cameras designed for visible/near infrared radiation to be used for spectral images in the mid infrared. This can lead to much lower costs for such imaging devices, and a better performance....

  1. Autostereoscopic image creation by hyperview matrix controlled single pixel rendering

    Science.gov (United States)

    Grasnick, Armin

    2017-06-01

    technology just with a simple equation. This formula can be utilized to create a specific hyperview matrix for a certain 3D display - independent of the technology used. A hyperview matrix may contain the references to loads of images and act as an instruction for a subsequent rendering process of particular pixels. Naturally, a single pixel will deliver an image with no resolution and does not provide any idea of the rendered scene. However, by implementing the method of pixel recycling, a 3D image can be perceived, even if all source images are different. It will be proven that several millions of perspectives can be rendered with the support of GPU rendering and benefit from the hyperview matrix. In result, a conventional autostereoscopic display, which is designed to represent only a few perspectives can be used to show a hyperview image by using a suitable hyperview matrix. It will be shown that a millions-of-views-hyperview-image can be presented on a conventional autostereoscopic display. For such an hyperview image it is required that all pixels of the displays are allocated by different source images. Controlled by the hyperview matrix, an adapted renderer can render a full hyperview image in real-time.

  2. Spectral Decomposition Algorithm (SDA)

    Data.gov (United States)

    National Aeronautics and Space Administration — Spectral Decomposition Algorithm (SDA) is an unsupervised feature extraction technique similar to PCA that was developed to better distinguish spectral features in...

  3. Irregular Morphing for Real-Time Rendering of Large Terrain

    Directory of Open Access Journals (Sweden)

    S. Kalem

    2016-06-01

    Full Text Available The following paper proposes an alternative approach to the real-time adaptive triangulation problem. A new region-based multi-resolution approach for terrain rendering is described which improves on-the-fly the distribution of the density of triangles inside the tile after selecting appropriate Level-Of-Detail by an adaptive sampling. This proposed approach organizes the heightmap into a QuadTree of tiles that are processed independently. This technique combines the benefits of both Triangular Irregular Network approach and region-based multi-resolution approach by improving the distribution of the density of triangles inside the tile. Our technique morphs the initial regular grid of the tile to deformed grid in order to minimize approximation error. The proposed technique strives to combine large tile size and real-time processing while guaranteeing an upper bound on the screen space error. Thus, this approach adapts terrain rendering process to local surface characteristics and enables on-the-fly handling of large amount of terrain data. Morphing is based-on the multi-resolution wavelet analysis. The use of the D2WT multi-resolution analysis of the terrain height-map speeds up processing and permits to satisfy an interactive terrain rendering. Tests and experiments demonstrate that Haar B-Spline wavelet, well known for its properties of localization and its compact support, is suitable for fast and accurate redistribution. Such technique could be exploited in client-server architecture for supporting interactive high-quality remote visualization of very large terrain.

  4. Rendering potential wearable robot designs with the LOPES gait trainer.

    Science.gov (United States)

    Koopman, B; van Asseldonk, E H F; van der Kooij, H; van Dijk, W; Ronsse, R

    2011-01-01

    In recent years, wearable robots (WRs) for rehabilitation, personal assistance, or human augmentation are gaining increasing interest. To make these devices more energy efficient, radical changes to the mechanical structure of the device are being considered. However, it remains very difficult to predict how people will respond to, and interact with, WRs that differ in terms of mechanical design. Users may adjust their gait pattern in response to the mechanical restrictions or properties of the device. The goal of this pilot study is to show the feasibility of rendering the mechanical properties of different potential WR designs using the robotic gait training device LOPES. This paper describes a new method that selectively cancels the dynamics of LOPES itself and adds the dynamics of the rendered WR using two parallel inverse models. Adaptive frequency oscillators were used to get estimates of the joint position, velocity, and acceleration. Using the inverse models, different WR designs can be evaluated, eliminating the need to build several prototypes. As a proof of principle, we simulated the effect of a very simple WR that consisted of a mass attached to the ankles. Preliminary results show that we are partially able to cancel the dynamics of LOPES. Additionally, the simulation of the mass showed an increase in muscle activity but not in the same level as during the control, where subjects actually carried the mass. In conclusion, the results in this paper suggest that LOPES can be used to render different WRs. In addition, it is very likely that the results can be further optimized when more effort is put in retrieving proper estimations for the velocity and acceleration, which are required for the inverse models. © 2011 IEEE

  5. Software System for Vocal Rendering of Printed Documents

    Directory of Open Access Journals (Sweden)

    Marian DARDALA

    2008-01-01

    Full Text Available The objective of this paper is to present a software system architecture developed to render the printed documents in a vocal form. On the other hand, in the paper are described the software solutions that exist as software components and are necessary for documents processing as well as for multimedia device controlling used by the system. The usefulness of this system is for people with visual disabilities that can access the contents of documents without that they be printed in Braille system or to exist in an audio form.

  6. 3D Volume Rendering and 3D Printing (Additive Manufacturing).

    Science.gov (United States)

    Katkar, Rujuta A; Taft, Robert M; Grant, Gerald T

    2018-07-01

    Three-dimensional (3D) volume-rendered images allow 3D insight into the anatomy, facilitating surgical treatment planning and teaching. 3D printing, additive manufacturing, and rapid prototyping techniques are being used with satisfactory accuracy, mostly for diagnosis and surgical planning, followed by direct manufacture of implantable devices. The major limitation is the time and money spent generating 3D objects. Printer type, material, and build thickness are known to influence the accuracy of printed models. In implant dentistry, the use of 3D-printed surgical guides is strongly recommended to facilitate planning and reduce risk of operative complications. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Partitioning of biocides between water and inorganic phases of render

    DEFF Research Database (Denmark)

    Urbanczyk, Michal; Bollmann, Ulla E.; Bester, Kai

    The use of biocides as additives for building materials has gained importance in recent years. These biocides are, e.g., applied to renders and paints to prevent them from microbial spoilage. However, these biocides can leach out into the environment. In order to better understand this leaching...... compared. The partitioning constants for calcium carbonate varied between 0.1 (isoproturon) and 1.1 (iodocarb) and 84.6 (dichlorooctylisothiazolinone), respectively. The results for barite, kaolinite and mica were in a similar range and usually the compounds with high partitioning constants for one mineral...

  8. Detection of pesticides and dioxins in tissue fats and rendering oils using laser-induced breakdown spectroscopy (LIBS).

    Science.gov (United States)

    Multari, Rosalie A; Cremers, David A; Scott, Thomas; Kendrick, Peter

    2013-03-13

    In laser-induced breakdown spectroscopy (LIBS), a series of powerful laser pulses are directed at a surface to form microplasmas from which light is collected and spectrally analyzed to identify the surface material. In most cases, no sample preparation is needed, and results can be automated and made available within seconds to minutes. Advances in LIBS spectral data analysis using multivariate regression techniques have led to the ability to detect organic chemicals in complex matrices such as foods. Here, the use of LIBS to differentiate samples contaminated with aldrin, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, chlorpyrifos, and dieldrin in the complex matrices of tissue fats and rendering oils is described. The pesticide concentrations in the samples ranged from 0.005 to 0.1 μg/g. All samples were successfully differentiated from each other and from control samples. Sample concentrations could also be differentiated for all of the pesticides and the dioxin included in this study. The results presented here provide first proof-of-principle data for the ability to create LIBS-based instrumentation for the rapid analysis of pesticide and dioxin contamination in tissue fat and rendered oils.

  9. Radionuclide cisternography: SPECT and 3D-rendering

    International Nuclear Information System (INIS)

    Henkes, H.; Huber, G.; Piepgras, U.; Hierholzer, J.; Cordes, M.

    1991-01-01

    Radionuclide cisternography is indicated in the clinical work-up for hydrocephalus, when searching for CSF leaks, and when testing whether or not intracranial cystic lesions are communicating with the adjacent subarachnoid space. This paper demonstrates the feasibility and diagnostic value of SPECT and subsequent 3D surface rendering in addition to conventional rectilinear CSF imaging in eight patients. Planar images allowed the evaluation of CSF circulation and the detection of CSF fistula. They were advantageous in examinations 48 h after application of 111 In-DTPA. SPECT scans, generated 4-24 h after tracer application, were superior in the delineation of basal cisterns, especially in early scans; this was helpful in patients with pooling due to CSF fistula and in cystic lesions near the skull base. A major drawback was the limited image quality of delayed scans, when the SPECT data were degraded by a low count rate. 3D surface rendering was easily feasible from SPECT data and yielded high quality images. The presentation of the spatial distribution of nuclide-contaminated CSF proved especially helpful in the area of the basal cisterns. (orig.) [de

  10. Non-Photorealistic Rendering in Chinese Painting of Animals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A set of algorithms is proposed in this paper to automatically transform 3D animal models to Chinese painting style. Inspired by real painting process in Chinese painting of animals, we divide the whole rendering process into two parts: borderline stroke making and interior shading. In borderline stroke making process we first find 3D model silhouettes in real-time depending on the viewing direction of a user. After retrieving silhouette information from all model edges, a stroke linking mechanism is applied to link these independent edges into a long stroke. Finally we grow a plain thin silhouette line to a stylus stroke with various widths at each control point and a 2D brush model is combined with it to simulate a Chinese painting stroke. In the interior shading pipeline, three stages are used to convert a Gouraud-shading image to a Chinese painting style image: color quantization, ink diffusion and box filtering. The color quantization stage assigns all pixels in an image into four color levels and each level represents a color layer in a Chinese painting. Ink diffusion stage is used to transfer inks and water between different levels and to grow areas in an irregular way. The box filtering stage blurs sharp borders between different levels to embellish the appearance of final interior shading image. In addition to automatic rendering, an interactive Chinese painting system which is equipped with friendly input devices can be also combined to generate more artistic Chinese painting images manually.

  11. Continuous Surface Rendering, Passing from CAD to Physical Representation

    Directory of Open Access Journals (Sweden)

    Mario Covarrubias

    2013-06-01

    Full Text Available This paper describes a desktop-mechatronic interface that has been conceived to support designers in the evaluation of aesthetic virtual shapes. This device allows a continuous and smooth free hand contact interaction on a real and developable plastic tape actuated by a servo-controlled mechanism. The objective in designing this device is to reproduce a virtual surface with a consistent physical rendering well adapted to designers' needs. The desktop-mechatronic interface consists in a servo-actuated plastic strip that has been devised and implemented using seven interpolation points. In fact, by using the MEC (Minimal Energy Curve Spline approach, a developable real surface is rendered taking into account the CAD geometry of the virtual shapes. In this paper, we describe the working principles of the interface by using both absolute and relative approaches to control the position on each single control point on the MEC spline. Then, we describe the methodology that has been implemented, passing from the CAD geometry, linked to VisualNastran in order to maintain the parametric properties of the virtual shape. Then, we present the co-simulation between VisualNastran and MATLAB/Simulink used for achieving this goal and controlling the system and finally, we present the results of the subsequent testing session specifically carried out to evaluate the accuracy and the effectiveness of the mechatronic device.

  12. Hardware-accelerated autostereogram rendering for interactive 3D visualization

    Science.gov (United States)

    Petz, Christoph; Goldluecke, Bastian; Magnor, Marcus

    2003-05-01

    Single Image Random Dot Stereograms (SIRDS) are an attractive way of depicting three-dimensional objects using conventional display technology. Once trained in decoupling the eyes' convergence and focusing, autostereograms of this kind are able to convey the three-dimensional impression of a scene. We present in this work an algorithm that generates SIRDS at interactive frame rates on a conventional PC. The presented system allows rotating a 3D geometry model and observing the object from arbitrary positions in real-time. Subjective tests show that the perception of a moving or rotating 3D scene presents no problem: The gaze remains focused onto the object. In contrast to conventional SIRDS algorithms, we render multiple pixels in a single step using a texture-based approach, exploiting the parallel-processing architecture of modern graphics hardware. A vertex program determines the parallax for each vertex of the geometry model, and the graphics hardware's texture unit is used to render the dot pattern. No data has to be transferred between main memory and the graphics card for generating the autostereograms, leaving CPU capacity available for other tasks. Frame rates of 25 fps are attained at a resolution of 1024x512 pixels on a standard PC using a consumer-grade nVidia GeForce4 graphics card, demonstrating the real-time capability of the system.

  13. Rendering of HDR content on LDR displays: an objective approach

    Science.gov (United States)

    Krasula, Lukáš; Narwaria, Manish; Fliegel, Karel; Le Callet, Patrick

    2015-09-01

    Dynamic range compression (or tone mapping) of HDR content is an essential step towards rendering it on traditional LDR displays in a meaningful way. This is however non-trivial and one of the reasons is that tone mapping operators (TMOs) usually need content-specific parameters to achieve the said goal. While subjective TMO parameter adjustment is the most accurate, it may not be easily deployable in many practical applications. Its subjective nature can also influence the comparison of different operators. Thus, there is a need for objective TMO parameter selection to automate the rendering process. To that end, we investigate into a new objective method for TMO parameters optimization. Our method is based on quantification of contrast reversal and naturalness. As an important advantage, it does not require any prior knowledge about the input HDR image and works independently on the used TMO. Experimental results using a variety of HDR images and several popular TMOs demonstrate the value of our method in comparison to default TMO parameter settings.

  14. Tomographic image reconstruction and rendering with texture-mapping hardware

    International Nuclear Information System (INIS)

    Azevedo, S.G.; Cabral, B.K.; Foran, J.

    1994-07-01

    The image reconstruction problem, also known as the inverse Radon transform, for x-ray computed tomography (CT) is found in numerous applications in medicine and industry. The most common algorithm used in these cases is filtered backprojection (FBP), which, while a simple procedure, is time-consuming for large images on any type of computational engine. Specially-designed, dedicated parallel processors are commonly used in medical CT scanners, whose results are then passed to graphics workstation for rendering and analysis. However, a fast direct FBP algorithm can be implemented on modern texture-mapping hardware in current high-end workstation platforms. This is done by casting the FBP algorithm as an image warping operation with summing. Texture-mapping hardware, such as that on the Silicon Graphics Reality Engine (TM), shows around 600 times speedup of backprojection over a CPU-based implementation (a 100 Mhz R4400 in this case). This technique has the further advantages of flexibility and rapid programming. In addition, the same hardware can be used for both image reconstruction and for volumetric rendering. The techniques can also be used to accelerate iterative reconstruction algorithms. The hardware architecture also allows more complex operations than straight-ray backprojection if they are required, including fan-beam, cone-beam, and curved ray paths, with little or no speed penalties

  15. Efficient visibility encoding for dynamic illumination in direct volume rendering.

    Science.gov (United States)

    Kronander, Joel; Jönsson, Daniel; Löw, Joakim; Ljung, Patric; Ynnerman, Anders; Unger, Jonas

    2012-03-01

    We present an algorithm that enables real-time dynamic shading in direct volume rendering using general lighting, including directional lights, point lights, and environment maps. Real-time performance is achieved by encoding local and global volumetric visibility using spherical harmonic (SH) basis functions stored in an efficient multiresolution grid over the extent of the volume. Our method enables high-frequency shadows in the spatial domain, but is limited to a low-frequency approximation of visibility and illumination in the angular domain. In a first pass, level of detail (LOD) selection in the grid is based on the current transfer function setting. This enables rapid online computation and SH projection of the local spherical distribution of visibility information. Using a piecewise integration of the SH coefficients over the local regions, the global visibility within the volume is then computed. By representing the light sources using their SH projections, the integral over lighting, visibility, and isotropic phase functions can be efficiently computed during rendering. The utility of our method is demonstrated in several examples showing the generality and interactive performance of the approach.

  16. Sparse PDF Volumes for Consistent Multi-Resolution Volume Rendering

    KAUST Repository

    Sicat, Ronell Barrera

    2014-12-31

    This paper presents a new multi-resolution volume representation called sparse pdf volumes, which enables consistent multi-resolution volume rendering based on probability density functions (pdfs) of voxel neighborhoods. These pdfs are defined in the 4D domain jointly comprising the 3D volume and its 1D intensity range. Crucially, the computation of sparse pdf volumes exploits data coherence in 4D, resulting in a sparse representation with surprisingly low storage requirements. At run time, we dynamically apply transfer functions to the pdfs using simple and fast convolutions. Whereas standard low-pass filtering and down-sampling incur visible differences between resolution levels, the use of pdfs facilitates consistent results independent of the resolution level used. We describe the efficient out-of-core computation of large-scale sparse pdf volumes, using a novel iterative simplification procedure of a mixture of 4D Gaussians. Finally, our data structure is optimized to facilitate interactive multi-resolution volume rendering on GPUs.

  17. Physically Based Rendering in the Nightshade NG Visualization Platform

    Science.gov (United States)

    Berglund, Karrie; Larey-Williams, Trystan; Spearman, Rob; Bogard, Arthur

    2015-01-01

    This poster describes our work on creating a physically based rendering model in Nightshade NG planetarium simulation and visualization software (project website: NightshadeSoftware.org). We discuss techniques used for rendering realistic scenes in the universe and dealing with astronomical distances in real time on consumer hardware. We also discuss some of the challenges of rewriting the software from scratch, a project which began in 2011.Nightshade NG can be a powerful tool for sharing data and visualizations. The desktop version of the software is free for anyone to download, use, and modify; it runs on Windows and Linux (and eventually Mac). If you are looking to disseminate your data or models, please stop by to discuss how we can work together.Nightshade software is used in literally hundreds of digital planetarium systems worldwide. Countless teachers and astronomy education groups run the software on flat screens. This wide use makes Nightshade an effective tool for dissemination to educators and the public.Nightshade NG is an especially powerful visualization tool when projected on a dome. We invite everyone to enter our inflatable dome in the exhibit hall to see this software in a 3D environment.

  18. Morphological pyramids in multiresolution MIP rendering of large volume data : Survey and new results

    NARCIS (Netherlands)

    Roerdink, J.B.T.M.

    We survey and extend nonlinear signal decompositions based on morphological pyramids, and their application to multiresolution maximum intensity projection (MIP) volume rendering with progressive refinement and perfect reconstruction. The structure of the resulting multiresolution rendering

  19. Adaptive proxy map server for efficient vector spatial data rendering

    Science.gov (United States)

    Sayar, Ahmet

    2013-01-01

    The rapid transmission of vector map data over the Internet is becoming a bottleneck of spatial data delivery and visualization in web-based environment because of increasing data amount and limited network bandwidth. In order to improve both the transmission and rendering performances of vector spatial data over the Internet, we propose a proxy map server enabling parallel vector data fetching as well as caching to improve the performance of web-based map servers in a dynamic environment. Proxy map server is placed seamlessly anywhere between the client and the final services, intercepting users' requests. It employs an efficient parallelization technique based on spatial proximity and data density in case distributed replica exists for the same spatial data. The effectiveness of the proposed technique is proved at the end of the article by the application of creating map images enriched with earthquake seismic data records.

  20. Development of a virtual speaking simulator using Image Based Rendering.

    Science.gov (United States)

    Lee, J M; Kim, H; Oh, M J; Ku, J H; Jang, D P; Kim, I Y; Kim, S I

    2002-01-01

    The fear of speaking is often cited as the world's most common social phobia. The rapid growth of computer technology has enabled the use of virtual reality (VR) for the treatment of the fear of public speaking. There are two techniques for building virtual environments for the treatment of this fear: a model-based and a movie-based method. Both methods have the weakness that they are unrealistic and not controllable individually. To understand these disadvantages, this paper presents a virtual environment produced with Image Based Rendering (IBR) and a chroma-key simultaneously. IBR enables the creation of realistic virtual environments where the images are stitched panoramically with the photos taken from a digital camera. And the use of chroma-keys puts virtual audience members under individual control in the environment. In addition, real time capture technique is used in constructing the virtual environments enabling spoken interaction between the subject and a therapist or another subject.

  1. Artist rendering of dust grains colliding at low speeds

    Science.gov (United States)

    2003-01-01

    Clues to the formation of planets and planetary rings -- like Saturn's dazzling ring system -- may be found by studying how dust grains interact as they collide at low speeds. To study the question of low-speed dust collisions, NASA sponsored the COLLisions Into Dust Experiment (COLLIDE) at the University of Colorado. It was designed to spring-launch marble-size projectiles into trays of powder similar to space or lunar dust. COLLIDE-1 (1998) discovered that collisions below a certain energy threshold eject no material. COLLIDE-2 was designed to identify where the threshold is. In COLLIDE-2, scientists nudged small projectiles into dust beds and recorded how the dust splashed outward (video frame at top; artist's rendering at bottom). The slowest impactor ejected no material and stuck in the target. The faster impactors produced ejecta; some rebounded while others stuck in the target.

  2. Latency in Distributed Acquisition and Rendering for Telepresence Systems.

    Science.gov (United States)

    Ohl, Stephan; Willert, Malte; Staadt, Oliver

    2015-12-01

    Telepresence systems use 3D techniques to create a more natural human-centered communication over long distances. This work concentrates on the analysis of latency in telepresence systems where acquisition and rendering are distributed. Keeping latency low is important to immerse users in the virtual environment. To better understand latency problems and to identify the source of such latency, we focus on the decomposition of system latency into sub-latencies. We contribute a model of latency and show how it can be used to estimate latencies in a complex telepresence dataflow network. To compare the estimates with real latencies in our prototype, we modify two common latency measurement methods. This presented methodology enables the developer to optimize the design, find implementation issues and gain deeper knowledge about specific sources of latency.

  3. Volumetric ambient occlusion for real-time rendering and games.

    Science.gov (United States)

    Szirmay-Kalos, L; Umenhoffer, T; Toth, B; Szecsi, L; Sbert, M

    2010-01-01

    This new algorithm, based on GPUs, can compute ambient occlusion to inexpensively approximate global-illumination effects in real-time systems and games. The first step in deriving this algorithm is to examine how ambient occlusion relates to the physically founded rendering equation. The correspondence stems from a fuzzy membership function that defines what constitutes nearby occlusions. The next step is to develop a method to calculate ambient occlusion in real time without precomputation. The algorithm is based on a novel interpretation of ambient occlusion that measures the relative volume of the visible part of the surface's tangent sphere. The new formula's integrand has low variation and thus can be estimated accurately with a few samples.

  4. D.Vanwijnsberghe, Autour de la Madeleine Renders

    Directory of Open Access Journals (Sweden)

    Muriel Verbeeck-Boutin

    2008-10-01

    Full Text Available Institution fédérale belge de réputation internationale, l’Institut royal du Patrimoine artistique, à Bruxelles,  célèbre cette année son soixantième anniversaire: c’est l’occasion de rappeler le prestige dont jouit depuis des décennies cet institut de recherche, de formation et de diffusion du savoir. Pour souligner l’événement, l’IRPA publie le quatrième volume de la collection Scientia Artis. Il présente sous le titre Autour de la Madeleine Renders un ensemble de recherches qui documentent...

  5. On-the-Fly Decompression and Rendering of Multiresolution Terrain

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, P; Cohen, J D

    2009-04-02

    We present a streaming geometry compression codec for multiresolution, uniformly-gridded, triangular terrain patches that supports very fast decompression. Our method is based on linear prediction and residual coding for lossless compression of the full-resolution data. As simplified patches on coarser levels in the hierarchy already incur some data loss, we optionally allow further quantization for more lossy compression. The quantization levels are adaptive on a per-patch basis, while still permitting seamless, adaptive tessellations of the terrain. Our geometry compression on such a hierarchy achieves compression ratios of 3:1 to 12:1. Our scheme is not only suitable for fast decompression on the CPU, but also for parallel decoding on the GPU with peak throughput over 2 billion triangles per second. Each terrain patch is independently decompressed on the fly from a variable-rate bitstream by a GPU geometry program with no branches or conditionals. Thus we can store the geometry compressed on the GPU, reducing storage and bandwidth requirements throughout the system. In our rendering approach, only compressed bitstreams and the decoded height values in the view-dependent 'cut' are explicitly stored on the GPU. Normal vectors are computed in a streaming fashion, and remaining geometry and texture coordinates, as well as mesh connectivity, are shared and re-used for all patches. We demonstrate and evaluate our algorithms on a small prototype system in which all compressed geometry fits in the GPU memory and decompression occurs on the fly every rendering frame without any cache maintenance.

  6. Trace elements record complex histories in diogenites

    Science.gov (United States)

    Balta, J. B.; Beck, A. W.; McSween, H. Y.

    2012-12-01

    Diogenite meteorites are cumulate rocks composed mostly of orthopyroxene and chemically linked to eucrites (basaltic) and howardites (brecciated mixtures of diogenites and eucrites). Together, they represent the largest single family of achondrite meteorites delivered to Earth, and have been spectrally linked to the asteroid 4 Vesta, the largest remaining basaltic protoplanet. However, this spectral link is non-unique as many basaltic asteroids likely formed and were destroyed in the early solar system. Recent work suggested that Vesta may be an unlikely parent body for the diogenites based on correlations between trace elements and short-lived isotope decay products, which would be unlikely to survive on a body as large as Vesta due to its long cooling history [1]. Recent analyses of terrestrial and martian olivines have demonstrated that trace element spatial distributions can preserve evidence of their crystallization history even when major elements have been homogenized [2]. We have mapped minor elements including Cr, Al, and Ti in seemingly homogeneous diogenite orthopyroxenes and found a variety of previously unobserved textures. The pyroxenes in one sample (GRA 98108) are seemingly large grains of variable shapes and sizes, but the trace elements reveal internal grain boundaries between roughly-equal sized original subgrains, with equilibrated metamorphic triple junctions between them and trace element depletions at the boundaries. These trends suggest extraction of trace elements by a magma along those relict grain boundaries during a reheating event. Two other samples show evidence of fracturing and annealing, with trace element mobility within grains. One sample appears to have remained a closed system during annealing (MET 01084), while the other has interacted with a fluid or magma to move elements along annealed cracks (LEW 88679). These relict features establish that the history of diogenite pyroxenes is more complex than their homogeneous major

  7. Information-efficient spectral imaging sensor

    Science.gov (United States)

    Sweatt, William C.; Gentry, Stephen M.; Boye, Clinton A.; Grotbeck, Carter L.; Stallard, Brian R.; Descour, Michael R.

    2003-01-01

    A programmable optical filter for use in multispectral and hyperspectral imaging. The filter splits the light collected by an optical telescope into two channels for each of the pixels in a row in a scanned image, one channel to handle the positive elements of a spectral basis filter and one for the negative elements of the spectral basis filter. Each channel for each pixel disperses its light into n spectral bins, with the light in each bin being attenuated in accordance with the value of the associated positive or negative element of the spectral basis vector. The spectral basis vector is constructed so that its positive elements emphasize the presence of a target and its negative elements emphasize the presence of the constituents of the background of the imaged scene. The attenuated light in the channels is re-imaged onto separate detectors for each pixel and then the signals from the detectors are combined to give an indication of the presence or not of the target in each pixel of the scanned scene. This system provides for a very efficient optical determination of the presence of the target, as opposed to the very data intensive data manipulations that are required in conventional hyperspectral imaging systems.

  8. Rendering Future Vegetation Change across Large Regions of the US

    Science.gov (United States)

    Sant'Anna Dias, Felipe; Gu, Yuting; Agarwalla, Yashika; Cheng, Yiwei; Patil, Sopan; Stieglitz, Marc; Turk, Greg

    2015-04-01

    We use two Machine Learning techniques, Decision Trees (DT) and Neural Networks (NN), to provide classified images and photorealistic renderings of future vegetation cover at three large regions in the US. The training data used to generate current vegetation cover include Landsat surface reflectance images, USGS Land Cover maps, 50 years of mean annual temperature and precipitation for the period 1950 - 2000, elevation, aspect and slope data. Present vegetation cover was generated on a 100m grid. Future vegetation cover for the period 2061- 2080 was predicted using the 1 km resolution bias corrected data from the NASA Goddard Institute for Space Studies Global Climate Model E simulation. The three test regions encompass a wide range of climatic gradients, topographic variation, and vegetation cover. The central Oregon site covers 19,182 square km and includes the Ochoco and Malheur National Forest. Vegetation cover is 50% evergreen forest and 50% shrubs and scrubland. The northwest Washington site covers 14,182 square km. Vegetation cover is 60% evergreen forest, 14% scrubs, 7% grassland, and 7% barren land. The remainder of the area includes deciduous forest, perennial snow cover, and wetlands. The third site, the Jemez mountain region of north central New Mexico, covers 5,500 square km. Vegetation cover is 47% evergreen forest, 31% shrubs, 13% grasses, and 3% deciduous forest. The remainder of the area includes developed and cultivated areas and wetlands. Using the above mentioned data sets we first trained our DT and NN models to reproduce current vegetation. The land cover classified images were compared directly to the USGS land cover data. The photorealistic generated vegetation images were compared directly to the remotely sensed surface reflectance maps. For all three sites, similarity between generated and observed vegetation cover was quite remarkable. The three trained models were then used to explore what the equilibrium vegetation would look like for

  9. Spectral gamuts and spectral gamut mapping

    Science.gov (United States)

    Rosen, Mitchell R.; Derhak, Maxim W.

    2006-01-01

    All imaging devices have two gamuts: the stimulus gamut and the response gamut. The response gamut of a print engine is typically described in CIE colorimetry units, a system derived to quantify human color response. More fundamental than colorimetric gamuts are spectral gamuts, based on radiance, reflectance or transmittance units. Spectral gamuts depend on the physics of light or on how materials interact with light and do not involve the human's photoreceptor integration or brain processing. Methods for visualizing a spectral gamut raise challenges as do considerations of how to utilize such a data-set for producing superior color reproductions. Recent work has described a transformation of spectra reduced to 6-dimensions called LabPQR. LabPQR was designed as a hybrid space with three explicit colorimetric axes and three additional spectral reconstruction axes. In this paper spectral gamuts are discussed making use of LabPQR. Also, spectral gamut mapping is considered in light of the colorimetric-spectral duality of the LabPQR space.

  10. Artist Material BRDF Database for Computer Graphics Rendering

    Science.gov (United States)

    Ashbaugh, Justin C.

    The primary goal of this thesis was to create a physical library of artist material samples. This collection provides necessary data for the development of a gonio-imaging system for use in museums to more accurately document their collections. A sample set was produced consisting of 25 panels and containing nearly 600 unique samples. Selected materials are representative of those commonly used by artists both past and present. These take into account the variability in visual appearance resulting from the materials and application techniques used. Five attributes of variability were identified including medium, color, substrate, application technique and overcoat. Combinations of these attributes were selected based on those commonly observed in museum collections and suggested by surveying experts in the field. For each sample material, image data is collected and used to measure an average bi-directional reflectance distribution function (BRDF). The results are available as a public-domain image and optical database of artist materials at art-si.org. Additionally, the database includes specifications for each sample along with other information useful for computer graphics rendering such as the rectified sample images and normal maps.

  11. Brain ageing changes proteoglycan sulfation, rendering perineuronal nets more inhibitory.

    Science.gov (United States)

    Foscarin, Simona; Raha-Chowdhury, Ruma; Fawcett, James W; Kwok, Jessica C F

    2017-06-28

    Chondroitin sulfate (CS) proteoglycans in perineuronal nets (PNNs) from the central nervous system (CNS) are involved in the control of plasticity and memory. Removing PNNs reactivates plasticity and restores memory in models of Alzheimer's disease and ageing. Their actions depend on the glycosaminoglycan (GAG) chains of CS proteoglycans, which are mainly sulfated in the 4 (C4S) or 6 (C6S) positions. While C4S is inhibitory, C6S is more permissive to axon growth, regeneration and plasticity. C6S decreases during critical period closure. We asked whether there is a late change in CS-GAG sulfation associated with memory loss in aged rats. Immunohistochemistry revealed a progressive increase in C4S and decrease in C6S from 3 to 18 months. GAGs extracted from brain PNNs showed a large reduction in C6S at 12 and 18 months, increasing the C4S/C6S ratio. There was no significant change in mRNA levels of the chondroitin sulfotransferases. PNN GAGs were more inhibitory to axon growth than those from the diffuse extracellular matrix. The 18-month PNN GAGs were more inhibitory than 3-month PNN GAGs. We suggest that the change in PNN GAG sulfation in aged brains renders the PNNs more inhibitory, which lead to a decrease in plasticity and adversely affect memory.

  12. Age, Health and Attractiveness Perception of Virtual (Rendered) Human Hair.

    Science.gov (United States)

    Fink, Bernhard; Hufschmidt, Carla; Hirn, Thomas; Will, Susanne; McKelvey, Graham; Lankhof, John

    2016-01-01

    The social significance of physical appearance and beauty has been documented in many studies. It is known that even subtle manipulations of facial morphology and skin condition can alter people's perception of a person's age, health and attractiveness. While the variation in facial morphology and skin condition cues has been studied quite extensively, comparably little is known on the effect of hair on social perception. This has been partly caused by the technical difficulty of creating appropriate stimuli for investigations of people's response to systematic variation of certain hair characteristics, such as color and style, while keeping other features constant. Here, we present a modeling approach to the investigation of human hair perception using computer-generated, virtual (rendered) human hair. In three experiments, we manipulated hair diameter (Experiment 1), hair density (Experiment 2), and hair style (Experiment 3) of human (female) head hair and studied perceptions of age, health and attractiveness. Our results show that even subtle changes in these features have an impact on hair perception. We discuss our findings with reference to previous studies on condition-dependent quality cues in women that influence human social perception, thereby suggesting that hair is a salient feature of human physical appearance, which contributes to the perception of beauty.

  13. Colorimetry and efficiency of white LEDs: Spectral width dependence

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Elaine; Edwards, Paul R.; Martin, Robert W. [Department of Physics, SUPA, Strathclyde University, Glasgow (United Kingdom)

    2012-03-15

    The potential colour rendering capability and efficiency of white LEDs constructed by a combination of individual red, green and blue (RGB) LEDs are analysed. The conventional measurement of colour rendering quality, the colour rendering index (CRI), is used as well as a recently proposed colour quality scale (CQS), designed to overcome some of the limitations of CRI when narrow-band emitters are being studied. The colour rendering performance is maximised by variation of the peak emission wavelength and relative intensity of the component LEDs, with the constraint that the spectral widths follow those measured in actual devices. The highest CRI achieved is 89.5, corresponding to a CQS value of 79, colour temperature of 3800 K and a luminous efficacy of radiation (LER) of 365 lm/W. By allowing the spectral width of the green LED to vary the CRI can be raised to 90.9, giving values of 82.5 and 370 lm/W for the CQS and LER, respectively. The significance of these values are discussed in terms of optimising the possible performance of RGB LEDs. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. New light field camera based on physical based rendering tracing

    Science.gov (United States)

    Chung, Ming-Han; Chang, Shan-Ching; Lee, Chih-Kung

    2014-03-01

    Even though light field technology was first invented more than 50 years ago, it did not gain popularity due to the limitation imposed by the computation technology. With the rapid advancement of computer technology over the last decade, the limitation has been uplifted and the light field technology quickly returns to the spotlight of the research stage. In this paper, PBRT (Physical Based Rendering Tracing) was introduced to overcome the limitation of using traditional optical simulation approach to study the light field camera technology. More specifically, traditional optical simulation approach can only present light energy distribution but typically lack the capability to present the pictures in realistic scenes. By using PBRT, which was developed to create virtual scenes, 4D light field information was obtained to conduct initial data analysis and calculation. This PBRT approach was also used to explore the light field data calculation potential in creating realistic photos. Furthermore, we integrated the optical experimental measurement results with PBRT in order to place the real measurement results into the virtually created scenes. In other words, our approach provided us with a way to establish a link of virtual scene with the real measurement results. Several images developed based on the above-mentioned approaches were analyzed and discussed to verify the pros and cons of the newly developed PBRT based light field camera technology. It will be shown that this newly developed light field camera approach can circumvent the loss of spatial resolution associated with adopting a micro-lens array in front of the image sensors. Detailed operational constraint, performance metrics, computation resources needed, etc. associated with this newly developed light field camera technique were presented in detail.

  15. Digital tomosynthesis rendering of joint margins for arthritis assessment

    Science.gov (United States)

    Duryea, Jeffrey W.; Neumann, Gesa; Yoshioka, Hiroshi; Dobbins, James T., III

    2004-05-01

    PURPOSE: Rheumatoid arthritis (RA) of the hand is a significant healthcare problem. Techniques to accurately quantity the structural changes from RA are crucial for the development and prescription of therapies. Analysis of radiographic joint space width (JSW) is widely used and has demonstrated promise. However, radiography presents a 2D view of the joint. In this study we performed tomosynthesis reconstructions of proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joints to measure the 3D joint structure. METHODS: We performed a reader study using simulated radiographs of 12 MCP and 12 PIP joints from skeletal specimens imaged with micro-CT. The tomosynthesis technique provided images of reconstructed planes with 0.75 mm spacing, which were presented to 2 readers with a computer tool. The readers were instructed to delineate the joint surfaces on tomosynthetic slices where they could visualize the margins. We performed a quantitative analysis of 5 slices surrounding the central portion of each joint. Reader-determined JSW was compared to a gold standard. As a figure of merit we calculated the average root-mean square deviation (RMSD). RESULTS: RMSD was 0.22 mm for both joints. For the individual joints, RMSD was 0.18 mm (MCP), and 0.26 mm (PIP). The reduced performance for the smaller PIP joints suggests that a slice spacing less than 0.75 mm may be more appropriate. CONCLUSIONS: We have demonstrated the capability of limited 3D rendering of joint surfaces using digital tomosynthesis. This technique promises to provide an improved method to visualize the structural changes of RA.

  16. Challenges for extension service to render efficient post-transformer ...

    African Journals Online (AJOL)

    LPhidza

    imperative in order to develop some understanding on decision making regarding sustainability. .... overall attractiveness or non-acceptability of an option in a choice, albeit not always an explicit ... “non-sustainability” is often framed as an uncompensated loss, creating some element ..... A psychological model. In: Toward a ...

  17. The solar element

    DEFF Research Database (Denmark)

    Kragh, Helge

    2009-01-01

    of the nineteenth century. In the modest form of a yellow spectral line known as D3, 'helium' was sometimes supposed to exist in the Sun's atmosphere, an idea which is traditionally ascribed to J. Norman Lockyer. Did Lockyer discover helium as a solar element? How was the suggestion received by chemists, physicists...... and astronomers in the period until the spring of 1895, when William Ramsay serendipitously found the gas in uranium minerals? The hypothetical element helium was fairly well known, yet Ramsay's discovery owed little or nothing to Lockyer's solar element. Indeed, for a brief while it was thought that the two...... elements might be different. The complex story of how helium became established as both a solar and terrestrial element involves precise observations as well as airy speculations. It is a story that is unique among the discovery histories of the chemical elements....

  18. Enhancement method for rendered images of home decoration based on SLIC superpixels

    Science.gov (United States)

    Dai, Yutong; Jiang, Xiaotong

    2018-04-01

    Rendering technology has been widely used in the home decoration industry in recent years for images of home decoration design. However, due to the fact that rendered images of home decoration design rely heavily on the parameters of renderer and the lights of scenes, most rendered images in this industry require further optimization afterwards. To reduce workload and enhance rendered images automatically, an algorithm utilizing neural networks is proposed in this manuscript. In addition, considering few extreme conditions such as strong sunlight and lights, SLIC superpixels based segmentation is used to choose out these bright areas of an image and enhance them independently. Finally, these chosen areas are merged with the entire image. Experimental results show that the proposed method effectively enhances the rendered images when compared with some existing algorithms. Besides, the proposed strategy is proven to be adaptable especially to those images with obvious bright parts.

  19. Influence of rendering methods on yield and quality of chicken fat recovered from broiler skin

    Directory of Open Access Journals (Sweden)

    Liang-Kun Lin

    2017-06-01

    Full Text Available Objective In order to utilize fat from broiler byproducts efficiently, it is necessary to develop an appropriate rendering procedure and establish quality information for the rendered fat. A study was therefore undertaken to evaluate the influence of rendering methods on the amounts and general properties of the fat recovered from broiler skin. Methods The yield and quality of the broiler skin fat rendered through high and lower energy microwave rendering (3.6 W/g for 10 min and 2.4 W/g for 10 min for high power microwave rendering (HPMR and high power microwave rendering (LPMR, respectively, oven baking (OB, at 180°C for 40 min, and water cooking (WC, boiling for 40 min were compared. Results Microwave-rendered skin exhibited the highest yields and fat recovery rates, followed by OB, and WC fats (p<0.05. HPMR fat had the highest L*, a*, and b* values, whereas WC fat had the highest moisture content, acid values, and thiobarbituric acid (TBA values (p<0.05. There was no significant difference in the acid value, peroxide value, and TBA values between HPMR and LPMR fats. Conclusion Microwave rendering at a power level of 3.6 W/g for 10 min is suggested base on the yield and quality of chicken fat.

  20. Real-time volume rendering of digital medical images on an iOS device

    Science.gov (United States)

    Noon, Christian; Holub, Joseph; Winer, Eliot

    2013-03-01

    Performing high quality 3D visualizations on mobile devices, while tantalizingly close in many areas, is still a quite difficult task. This is especially true for 3D volume rendering of digital medical images. Allowing this would empower medical personnel a powerful tool to diagnose and treat patients and train the next generation of physicians. This research focuses on performing real time volume rendering of digital medical images on iOS devices using custom developed GPU shaders for orthogonal texture slicing. An interactive volume renderer was designed and developed with several new features including dynamic modification of render resolutions, an incremental render loop, a shader-based clipping algorithm to support OpenGL ES 2.0, and an internal backface culling algorithm for properly sorting rendered geometry with alpha blending. The application was developed using several application programming interfaces (APIs) such as OpenSceneGraph (OSG) as the primary graphics renderer coupled with iOS Cocoa Touch for user interaction, and DCMTK for DICOM I/O. The developed application rendered volume datasets over 450 slices up to 50-60 frames per second, depending on the specific model of the iOS device. All rendering is done locally on the device so no Internet connection is required.

  1. Adaptive Spectral Doppler Estimation

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2009-01-01

    . The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to pro- vide good spectral resolution and contrast even when the ob- servation window is very short. The 2 adaptive techniques are tested......In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence...... and compared with the averaged periodogram (Welch’s method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set...

  2. Introduction to spectral theory

    CERN Document Server

    Levitan, B M

    1975-01-01

    This monograph is devoted to the spectral theory of the Sturm- Liouville operator and to the spectral theory of the Dirac system. In addition, some results are given for nth order ordinary differential operators. Those parts of this book which concern nth order operators can serve as simply an introduction to this domain, which at the present time has already had time to become very broad. For the convenience of the reader who is not familar with abstract spectral theory, the authors have inserted a chapter (Chapter 13) in which they discuss this theory, concisely and in the main without proofs, and indicate various connections with the spectral theory of differential operators.

  3. Holonomy loops, spectral triples and quantum gravity

    DEFF Research Database (Denmark)

    Johannes, Aastrup; Grimstrup, Jesper Møller; Nest, Ryszard

    2009-01-01

    We review the motivation, construction and physical interpretation of a semi-finite spectral triple obtained through a rearrangement of central elements of loop quantum gravity. The triple is based on a countable set of oriented graphs and the algebra consists of generalized holonomy loops...

  4. Three-dimensional spiral CT during arterial portography: comparison of three rendering techniques.

    Science.gov (United States)

    Heath, D G; Soyer, P A; Kuszyk, B S; Bliss, D F; Calhoun, P S; Bluemke, D A; Choti, M A; Fishman, E K

    1995-07-01

    The three most common techniques for three-dimensional reconstruction are surface rendering, maximum-intensity projection (MIP), and volume rendering. Surface-rendering algorithms model objects as collections of geometric primitives that are displayed with surface shading. The MIP algorithm renders an image by selecting the voxel with the maximum intensity signal along a line extended from the viewer's eye through the data volume. Volume-rendering algorithms sum the weighted contributions of all voxels along the line. Each technique has advantages and shortcomings that must be considered during selection of one for a specific clinical problem and during interpretation of the resulting images. With surface rendering, sharp-edged, clear three-dimensional reconstruction can be completed on modest computer systems; however, overlapping structures cannot be visualized and artifacts are a problem. MIP is computationally a fast technique, but it does not allow depiction of overlapping structures, and its images are three-dimensionally ambiguous unless depth cues are provided. Both surface rendering and MIP use less than 10% of the image data. In contrast, volume rendering uses nearly all of the data, allows demonstration of overlapping structures, and engenders few artifacts, but it requires substantially more computer power than the other techniques.

  5. 31 CFR 515.548 - Services rendered by Cuba to United States aircraft.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Services rendered by Cuba to United... REGULATIONS Licenses, Authorizations, and Statements of Licensing Policy § 515.548 Services rendered by Cuba to United States aircraft. Specific licenses are issued for payment to Cuba of charges for services...

  6. On the design of a real-time volume rendering engine

    NARCIS (Netherlands)

    Smit, Jaap; Wessels, H.L.F.; van der Horst, A.; Bentum, Marinus Jan

    1992-01-01

    An architecture for a Real-Time Volume Rendering Engine (RT-VRE) is given, capable of computing 750 × 750 × 512 samples from a 3D dataset at a rate of 25 images per second. The RT-VRE uses for this purpose 64 dedicated rendering chips, cooperating with 16 RISC-processors. A plane interpolator

  7. On the design of a real-time volume rendering engine

    NARCIS (Netherlands)

    Smit, Jaap; Wessels, H.J.; van der Horst, A.; Bentum, Marinus Jan

    1995-01-01

    An architecture for a Real-Time Volume Rendering Engine (RT-VRE) is given, capable of computing 750 × 750 × 512 samples from a 3D dataset at a rate of 25 images per second. The RT-VRE uses for this purpose 64 dedicated rendering chips, cooperating with 16 RISC-processors. A plane interpolator

  8. An improved method of continuous LOD based on fractal theory in terrain rendering

    Science.gov (United States)

    Lin, Lan; Li, Lijun

    2007-11-01

    With the improvement of computer graphic hardware capability, the algorithm of 3D terrain rendering is going into the hot topic of real-time visualization. In order to solve conflict between the rendering speed and reality of rendering, this paper gives an improved method of terrain rendering which improves the traditional continuous level of detail technique based on fractal theory. This method proposes that the program needn't to operate the memory repeatedly to obtain different resolution terrain model, instead, obtains the fractal characteristic parameters of different region according to the movement of the viewpoint. Experimental results show that the method guarantees the authenticity of landscape, and increases the real-time 3D terrain rendering speed.

  9. On Longitudinal Spectral Coherence

    DEFF Research Database (Denmark)

    Kristensen, Leif

    1979-01-01

    It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between ...... observation sites and the turbulence intensity influence the results. The limitations of the theory are discussed....

  10. Full waveform inversion based on the optimized gradient and its spectral implementation

    KAUST Repository

    Wu, Zedong; Alkhalifah, Tariq Ali

    2014-01-01

    for the convergence are available, the high number of iterations required to approach a solution renders FWI as very expensive (especially in 3D). A spectral implementation in which the wavefields are extrapolated and gradients are calculated in the wavenumber domain

  11. Design and Implementation of High-Performance GIS Dynamic Objects Rendering Engine

    Science.gov (United States)

    Zhong, Y.; Wang, S.; Li, R.; Yun, W.; Song, G.

    2017-12-01

    Spatio-temporal dynamic visualization is more vivid than static visualization. It important to use dynamic visualization techniques to reveal the variation process and trend vividly and comprehensively for the geographical phenomenon. To deal with challenges caused by dynamic visualization of both 2D and 3D spatial dynamic targets, especially for different spatial data types require high-performance GIS dynamic objects rendering engine. The main approach for improving the rendering engine with vast dynamic targets relies on key technologies of high-performance GIS, including memory computing, parallel computing, GPU computing and high-performance algorisms. In this study, high-performance GIS dynamic objects rendering engine is designed and implemented for solving the problem based on hybrid accelerative techniques. The high-performance GIS rendering engine contains GPU computing, OpenGL technology, and high-performance algorism with the advantage of 64-bit memory computing. It processes 2D, 3D dynamic target data efficiently and runs smoothly with vast dynamic target data. The prototype system of high-performance GIS dynamic objects rendering engine is developed based SuperMap GIS iObjects. The experiments are designed for large-scale spatial data visualization, the results showed that the high-performance GIS dynamic objects rendering engine have the advantage of high performance. Rendering two-dimensional and three-dimensional dynamic objects achieve 20 times faster on GPU than on CPU.

  12. COMPANION ANIMALS SYMPOSIUM: Rendered ingredients significantly influence sustainability, quality, and safety of pet food.

    Science.gov (United States)

    Meeker, D L; Meisinger, J L

    2015-03-01

    The rendering industry collects and safely processes approximately 25 million t of animal byproducts each year in the United States. Rendering plants process a variety of raw materials from food animal production, principally offal from slaughterhouses, but include whole animals that die on farms or in transit and other materials such as bone, feathers, and blood. By recycling these byproducts into various protein, fat, and mineral products, including meat and bone meal, hydrolyzed feather meal, blood meal, and various types of animal fats and greases, the sustainability of food animal production is greatly enhanced. The rendering industry is conscious of its role in the prevention of disease and microbiological control and providing safe feed ingredients for livestock, poultry, aquaculture, and pets. The processing of otherwise low-value OM from the livestock production and meat processing industries through rendering drastically reduces the amount of waste. If not rendered, biological materials would be deposited in landfills, burned, buried, or inappropriately dumped with large amounts of carbon dioxide, ammonia, and other compounds polluting air and water. The majority of rendered protein products are used as animal feed. Rendered products are especially valuable to the livestock and pet food industries because of their high protein content, digestible AA levels (especially lysine), mineral availability (especially calcium and phosphorous), and relatively low cost in relation to their nutrient value. The use of these reclaimed and recycled materials in pet food is a much more sustainable model than using human food for pets.

  13. Standard elements; Elements standards

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Following his own experience the author recalls the various advantages, especially in the laboratory, of having pre-fabricated vacuum-line components at his disposal. (author) [French] A la suite de sa propre experience, l'auteur veut rappeler les divers avantages que presente, tout particulierement en laboratoire, le fait d'avoir a sa disposition des elements pre-fabriques de canalisations a vide. (auteur)

  14. Three-dimensional rendering of segmented object using matlab - biomed 2010.

    Science.gov (United States)

    Anderson, Jeffrey R; Barrett, Steven F

    2010-01-01

    The three-dimensional rendering of microscopic objects is a difficult and challenging task that often requires specialized image processing techniques. Previous work has been described of a semi-automatic segmentation process of fluorescently stained neurons collected as a sequence of slice images with a confocal laser scanning microscope. Once properly segmented, each individual object can be rendered and studied as a three-dimensional virtual object. This paper describes the work associated with the design and development of Matlab files to create three-dimensional images from the segmented object data previously mentioned. Part of the motivation for this work is to integrate both the segmentation and rendering processes into one software application, providing a seamless transition from the segmentation tasks to the rendering and visualization tasks. Previously these tasks were accomplished on two different computer systems, windows and Linux. This transition basically limits the usefulness of the segmentation and rendering applications to those who have both computer systems readily available. The focus of this work is to create custom Matlab image processing algorithms for object rendering and visualization, and merge these capabilities to the Matlab files that were developed especially for the image segmentation task. The completed Matlab application will contain both the segmentation and rendering processes in a single graphical user interface, or GUI. This process for rendering three-dimensional images in Matlab requires that a sequence of two-dimensional binary images, representing a cross-sectional slice of the object, be reassembled in a 3D space, and covered with a surface. Additional segmented objects can be rendered in the same 3D space. The surface properties of each object can be varied by the user to aid in the study and analysis of the objects. This inter-active process becomes a powerful visual tool to study and understand microscopic objects.

  15. Spectrally accurate contour dynamics

    International Nuclear Information System (INIS)

    Van Buskirk, R.D.; Marcus, P.S.

    1994-01-01

    We present an exponentially accurate boundary integral method for calculation the equilibria and dynamics of piece-wise constant distributions of potential vorticity. The method represents contours of potential vorticity as a spectral sum and solves the Biot-Savart equation for the velocity by spectrally evaluating a desingularized contour integral. We use the technique in both an initial-value code and a newton continuation method. Our methods are tested by comparing the numerical solutions with known analytic results, and it is shown that for the same amount of computational work our spectral methods are more accurate than other contour dynamics methods currently in use

  16. Spectral radius of graphs

    CERN Document Server

    Stevanovic, Dragan

    2015-01-01

    Spectral Radius of Graphs provides a thorough overview of important results on the spectral radius of adjacency matrix of graphs that have appeared in the literature in the preceding ten years, most of them with proofs, and including some previously unpublished results of the author. The primer begins with a brief classical review, in order to provide the reader with a foundation for the subsequent chapters. Topics covered include spectral decomposition, the Perron-Frobenius theorem, the Rayleigh quotient, the Weyl inequalities, and the Interlacing theorem. From this introduction, the

  17. Quasistatic field simulations based on finite elements and spectral methods applied to superconducting magnets; Quasistatische Feldsimulationen auf der Basis von Finiten Elementen und Spektralmethoden in der Anwendung auf supraleitende Magnete

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Stephan

    2009-03-30

    This thesis is concerned with the numerical simulation of electromagnetic fields in the quasi-static approximation which is applicable in many practical cases. Main emphasis is put on higher-order finite element methods. Quasi-static applications can be found, e.g., in accelerator physics in terms of the design of magnets required for beam guidance, in power engineering as well as in high-voltage engineering. Especially during the first design and optimization phase of respective devices, numerical models offer a cheap alternative to the often costly assembly of prototypes. However, large differences in the magnitude of the material parameters and the geometric dimensions as well as in the time-scales of the electromagnetic phenomena involved lead to an unacceptably long simulation time or to an inadequately large memory requirement. Under certain circumstances, the simulation itself and, in turn, the desired design improvement becomes even impossible. In the context of this thesis, two strategies aiming at the extension of the range of application for numerical simulations based on the finite element method are pursued. The first strategy consists in parallelizing existing methods such that the computation can be distributed over several computers or cores of a processor. As a consequence, it becomes feasible to simulate a larger range of devices featuring more degrees of freedom in the numerical model than before. This is illustrated for the calculation of the electromagnetic fields, in particular of the eddy-current losses, inside a superconducting dipole magnet developed at the GSI Helmholtzzentrum fuer Schwerionenforschung as a part of the FAIR project. As the second strategy to improve the efficiency of numerical simulations, a hybrid discretization scheme exploiting certain geometrical symmetries is established. Using this method, a significant reduction of the numerical effort in terms of required degrees of freedom for a given accuracy is achieved. The

  18. Characterization of a smartphone size haptic rendering system based on thin-film AlN actuators on glass substrates

    Science.gov (United States)

    Bernard, F.; Casset, F.; Danel, J. S.; Chappaz, C.; Basrour, S.

    2016-08-01

    This paper presents for the first time the characterization of a smartphone-size haptic rendering system based on the friction modulation effect. According to previous work and finite element modeling, the homogeneous flexural modes are needed to get the haptic feedback effect. The device studied consists of a thin film AlN transducers deposited on an 110  ×  65 mm2 glass substrate. The transducer’s localization on the glass plate allows a transparent central area of 90  ×  49 mm2. Electrical and mechanical parameters of the system are extracted from measurement. From this extraction, the electrical impedance matching reduced the applied voltage to 17.5 V AC and the power consumption to 1.53 W at the resonance frequency of the vibrating system to reach the haptic rendering specification. Transient characterizations of the actuation highlight a delay under the dynamic tactile detection. The characterization of the AlN transducers used as sensors, including the noise rejection, the delay or the output charge amplitude allows detections with high accuracy of any variation due to external influences. Those specifications are the first step to a low-power-consumption feedback-looped system.

  19. Characterization of a smartphone size haptic rendering system based on thin-film AlN actuators on glass substrates

    International Nuclear Information System (INIS)

    Bernard, F; Basrour, S; Casset, F; Danel, J S; Chappaz, C

    2016-01-01

    This paper presents for the first time the characterization of a smartphone-size haptic rendering system based on the friction modulation effect. According to previous work and finite element modeling, the homogeneous flexural modes are needed to get the haptic feedback effect. The device studied consists of a thin film AlN transducers deposited on an 110  ×  65 mm 2 glass substrate. The transducer’s localization on the glass plate allows a transparent central area of 90  ×  49 mm 2 . Electrical and mechanical parameters of the system are extracted from measurement. From this extraction, the electrical impedance matching reduced the applied voltage to 17.5 V AC and the power consumption to 1.53 W at the resonance frequency of the vibrating system to reach the haptic rendering specification. Transient characterizations of the actuation highlight a delay under the dynamic tactile detection. The characterization of the AlN transducers used as sensors, including the noise rejection, the delay or the output charge amplitude allows detections with high accuracy of any variation due to external influences. Those specifications are the first step to a low-power-consumption feedback-looped system. (paper)

  20. Spectral unmixing: estimating partial abundances

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-01-01

    Full Text Available techniques is complicated when considering very similar spectral signatures. Iron-bearing oxide/hydroxide/sulfate minerals have similar spectral signatures. The study focuses on how could estimates of abundances of spectrally similar iron-bearing oxide...

  1. Element-by-element parallel spectral-element methods for 3-D teleseismic wave modeling

    KAUST Repository

    Liu, Shaolin; Yang, Dinghui; Dong, Xingpeng; Liu, Qiancheng; Zheng, Yongchang

    2017-01-01

    The development of an efficient algorithm for teleseismic wave field modeling is valuable for calculating the gradients of the misfit function (termed misfit gradients) or Fréchet derivatives when the teleseismic waveform is used for adjoint

  2. Rectangular spectral collocation

    KAUST Repository

    Driscoll, Tobin A.; Hale, Nicholas

    2015-01-01

    Boundary conditions in spectral collocation methods are typically imposed by removing some rows of the discretized differential operator and replacing them with others that enforce the required conditions at the boundary. A new approach based upon

  3. Vowel Inherent Spectral Change

    CERN Document Server

    Assmann, Peter

    2013-01-01

    It has been traditional in phonetic research to characterize monophthongs using a set of static formant frequencies, i.e., formant frequencies taken from a single time-point in the vowel or averaged over the time-course of the vowel. However, over the last twenty years a growing body of research has demonstrated that, at least for a number of dialects of North American English, vowels which are traditionally described as monophthongs often have substantial spectral change. Vowel Inherent Spectral Change has been observed in speakers’ productions, and has also been found to have a substantial effect on listeners’ perception. In terms of acoustics, the traditional categorical distinction between monophthongs and diphthongs can be replaced by a gradient description of dynamic spectral patterns. This book includes chapters addressing various aspects of vowel inherent spectral change (VISC), including theoretical and experimental studies of the perceptually relevant aspects of VISC, the relationship between ar...

  4. Spectrally selective glazings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    Spectrally selective glazing is window glass that permits some portions of the solar spectrum to enter a building while blocking others. This high-performance glazing admits as much daylight as possible while preventing transmission of as much solar heat as possible. By controlling solar heat gains in summer, preventing loss of interior heat in winter, and allowing occupants to reduce electric lighting use by making maximum use of daylight, spectrally selective glazing significantly reduces building energy consumption and peak demand. Because new spectrally selective glazings can have a virtually clear appearance, they admit more daylight and permit much brighter, more open views to the outside while still providing the solar control of the dark, reflective energy-efficient glass of the past. This Federal Technology Alert provides detailed information and procedures for Federal energy managers to consider spectrally selective glazings. The principle of spectrally selective glazings is explained. Benefits related to energy efficiency and other architectural criteria are delineated. Guidelines are provided for appropriate application of spectrally selective glazing, and step-by-step instructions are given for estimating energy savings. Case studies are also presented to illustrate actual costs and energy savings. Current manufacturers, technology users, and references for further reading are included for users who have questions not fully addressed here.

  5. Automating Geospatial Visualizations with Smart Default Renderers for Data Exploration Web Applications

    Science.gov (United States)

    Ekenes, K.

    2017-12-01

    This presentation will outline the process of creating a web application for exploring large amounts of scientific geospatial data using modern automated cartographic techniques. Traditional cartographic methods, including data classification, may inadvertently hide geospatial and statistical patterns in the underlying data. This presentation demonstrates how to use smart web APIs that quickly analyze the data when it loads, and provides suggestions for the most appropriate visualizations based on the statistics of the data. Since there are just a few ways to visualize any given dataset well, it is imperative to provide smart default color schemes tailored to the dataset as opposed to static defaults. Since many users don't go beyond default values, it is imperative that they are provided with smart default visualizations. Multiple functions for automating visualizations are available in the Smart APIs, along with UI elements allowing users to create more than one visualization for a dataset since there isn't a single best way to visualize a given dataset. Since bivariate and multivariate visualizations are particularly difficult to create effectively, this automated approach removes the guesswork out of the process and provides a number of ways to generate multivariate visualizations for the same variables. This allows the user to choose which visualization is most appropriate for their presentation. The methods used in these APIs and the renderers generated by them are not available elsewhere. The presentation will show how statistics can be used as the basis for automating default visualizations of data along continuous ramps, creating more refined visualizations while revealing the spread and outliers of the data. Adding interactive components to instantaneously alter visualizations allows users to unearth spatial patterns previously unknown among one or more variables. These applications may focus on a single dataset that is frequently updated, or configurable

  6. Color-coded volume rendering for three-dimensional reconstructions of CT data

    International Nuclear Information System (INIS)

    Rieker, O.; Mildenberger, P.; Thelen, M.

    1999-01-01

    Purpose: To evaluate a technique of colored three-dimensional reconstructions without segmentation. Material and methods: Color-coded volume rendered images were reconstructed from the volume data of 25 thoracic, abdominal, musculoskeletal, and vascular helical CT scans using commercial software. The CT volume rendered voxels were encoded with color in the following manner. Opacity, hue, lightness, and chroma were assigned to each of four classes defined by CT number. Color-coded reconstructions were compared to the corresponding grey-scale coded reconstructions. Results: Color-coded volume rendering enabled realistic visualization of pathologic findings when there was sufficient difference in CT density. Segmentation was necessary in some cases to demonstrate small details in a complex volume. Conclusion: Color-coded volume rendering allowed lifelike visualisation of CT volumes without the need of segmentation in most cases. (orig.) [de

  7. Rendering Large-Scale Terrain Models and Positioning Objects in Relation to 3D Terrain

    National Research Council Canada - National Science Library

    Hittner, Brian

    2003-01-01

    .... Rendering large scale landscapes based on 3D geometry generally did not occur because the scenes generated tended to use up too much system memory and overburden 3D graphics cards with too many polygons...

  8. Flight-appropriate 3D Terrain-rendering Toolkit for Synthetic Vision, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The TerraBlocksTM 3D terrain data format and terrain-block-rendering methodology provides an enabling basis for successful commercial deployment of...

  9. Processing-in-Memory Enabled Graphics Processors for 3D Rendering

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Chenhao; Song, Shuaiwen; Wang, Jing; Zhang, Weigong; Fu, Xin

    2017-02-06

    The performance of 3D rendering of Graphics Processing Unit that convents 3D vector stream into 2D frame with 3D image effects significantly impact users’ gaming experience on modern computer systems. Due to the high texture throughput in 3D rendering, main memory bandwidth becomes a critical obstacle for improving the overall rendering performance. 3D stacked memory systems such as Hybrid Memory Cube (HMC) provide opportunities to significantly overcome the memory wall by directly connecting logic controllers to DRAM dies. Based on the observation that texel fetches significantly impact off-chip memory traffic, we propose two architectural designs to enable Processing-In-Memory based GPU for efficient 3D rendering.

  10. Flight-appropriate 3D Terrain-rendering Toolkit for Synthetic Vision, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — TerraMetrics proposes an SBIR Phase I R/R&D effort to develop a key 3D terrain-rendering technology that provides the basis for successful commercial deployment...

  11. A point-based rendering approach for real-time interaction on mobile devices

    Institute of Scientific and Technical Information of China (English)

    LIANG XiaoHui; ZHAO QinPing; HE ZhiYing; XIE Ke; LIU YuBo

    2009-01-01

    Mobile device is an Important interactive platform. Due to the limitation of computation, memory, display area and energy, how to realize the efficient and real-time interaction of 3D models based on mobile devices is an important research topic. Considering features of mobile devices, this paper adopts remote rendering mode and point models, and then, proposes a transmission and rendering approach that could interact in real time. First, improved simplification algorithm based on MLS and display resolution of mobile devices is proposed. Then, a hierarchy selection of point models and a QoS transmission control strategy are given based on interest area of operator, interest degree of object in the virtual environment and rendering error. They can save the energy consumption. Finally, the rendering and interaction of point models are completed on mobile devices. The experiments show that our method is efficient.

  12. Physically-Based Rendering of Particle-Based Fluids with Light Transport Effects

    Science.gov (United States)

    Beddiaf, Ali; Babahenini, Mohamed Chaouki

    2018-03-01

    Recent interactive rendering approaches aim to efficiently produce images. However, time constraints deeply affect their output accuracy and realism (many light phenomena are poorly or not supported at all). To remedy this issue, in this paper, we propose a physically-based fluid rendering approach. First, while state-of-the-art methods focus on isosurface rendering with only two refractions, our proposal (1) considers the fluid as a heterogeneous participating medium with refractive boundaries, and (2) supports both multiple refractions and scattering. Second, the proposed solution is fully particle-based in the sense that no particles transformation into a grid is required. This interesting feature makes it able to handle many particle types (water, bubble, foam, and sand). On top of that, a medium with different fluids (color, phase function, etc.) can also be rendered.

  13. Major Deficiencies Preventing Auditors From Rendering Audit Opinions on DOD General Fund Financial Statements

    National Research Council Canada - National Science Library

    Rauu, Russell

    1995-01-01

    .... We plan to issue a similar report each year. The audit objective was to identify and summarize the major deficiencies that prevented auditors from rendering audit opinions, other than disclaimers, on Army and Air Force general fund financial...

  14. Functionality and Performance Visualization of the Distributed High Quality Volume Renderer (HVR)

    KAUST Repository

    Shaheen, Sara

    2012-07-01

    Volume rendering systems are designed to provide means to enable scientists and a variety of experts to interactively explore volume data through 3D views of the volume. However, volume rendering techniques are computationally intensive tasks. Moreover, parallel distributed volume rendering systems and multi-threading architectures were suggested as natural solutions to provide an acceptable volume rendering performance for very large volume data sizes, such as Electron Microscopy data (EM). This in turn adds another level of complexity when developing and manipulating volume rendering systems. Given that distributed parallel volume rendering systems are among the most complex systems to develop, trace and debug, it is obvious that traditional debugging tools do not provide enough support. As a consequence, there is a great demand to provide tools that are able to facilitate the manipulation of such systems. This can be achieved by utilizing the power of compute graphics in designing visual representations that reflect how the system works and that visualize the current performance state of the system.The work presented is categorized within the field of software Visualization, where Visualization is used to serve visualizing and understanding various software. In this thesis, a number of visual representations that reflect a number of functionality and performance aspects of the distributed HVR, a high quality volume renderer system that uses various techniques to visualize large volume sizes interactively. This work is provided to visualize different stages of the parallel volume rendering pipeline of HVR. This is along with means of performance analysis through a number of flexible and dynamic visualizations that reflect the current state of the system and enables manipulation of them at runtime. Those visualization are aimed to facilitate debugging, understanding and analyzing the distributed HVR.

  15. Specification and time required for the application of a lime-based render inside historic buildings

    Directory of Open Access Journals (Sweden)

    Vasco Peixoto de Freitas

    2008-01-01

    Full Text Available Intervention in ancient buildings with historical and architectural value requires traditional techniques, such as the use of lime mortars for internal and external wall renderings. In order to ensure the desired performance, these rendering mortars must be rigorously specified and quality controls have to be performed during application. The choice of mortar composition should take account of factors such as compatibility with the substrate, mechanical requirements and water behaviour. The construction schedule, which used to be considered a second order variable, nowadays plays a decisive role in the selection of the rendering technique, given its effects upon costs. How should lime-based mortars be specified? How much time is required for the application and curing of a lime-based render? This paper reflects upon the feasibility of using traditional lime mortars in three-layer renders inside churches and monasteries under adverse hygrothermal conditions and when time is critical. A case study is presented in which internal lime mortar renderings were applied in a church in Northern Portugal, where the very high relative humidity meant that several months were necessary before the drying process was complete.

  16. On-the-fly generation and rendering of infinite cities on the GPU

    KAUST Repository

    Steinberger, Markus

    2014-05-01

    In this paper, we present a new approach for shape-grammar-based generation and rendering of huge cities in real-time on the graphics processing unit (GPU). Traditional approaches rely on evaluating a shape grammar and storing the geometry produced as a preprocessing step. During rendering, the pregenerated data is then streamed to the GPU. By interweaving generation and rendering, we overcome the problems and limitations of streaming pregenerated data. Using our methods of visibility pruning and adaptive level of detail, we are able to dynamically generate only the geometry needed to render the current view in real-time directly on the GPU. We also present a robust and efficient way to dynamically update a scene\\'s derivation tree and geometry, enabling us to exploit frame-to-frame coherence. Our combined generation and rendering is significantly faster than all previous work. For detailed scenes, we are capable of generating geometry more rapidly than even just copying pregenerated data from main memory, enabling us to render cities with thousands of buildings at up to 100 frames per second, even with the camera moving at supersonic speed. © 2014 The Author(s) Computer Graphics Forum © 2014 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

  17. Using neutrosophic graph cut segmentation algorithm for qualified rendering image selection in thyroid elastography video.

    Science.gov (United States)

    Guo, Yanhui; Jiang, Shuang-Quan; Sun, Baiqing; Siuly, Siuly; Şengür, Abdulkadir; Tian, Jia-Wei

    2017-12-01

    Recently, elastography has become very popular in clinical investigation for thyroid cancer detection and diagnosis. In elastogram, the stress results of the thyroid are displayed using pseudo colors. Due to variation of the rendering results in different frames, it is difficult for radiologists to manually select the qualified frame image quickly and efficiently. The purpose of this study is to find the qualified rendering result in the thyroid elastogram. This paper employs an efficient thyroid ultrasound image segmentation algorithm based on neutrosophic graph cut to find the qualified rendering images. Firstly, a thyroid ultrasound image is mapped into neutrosophic set, and an indeterminacy filter is constructed to reduce the indeterminacy of the spatial and intensity information in the image. A graph is defined on the image and the weight for each pixel is represented using the value after indeterminacy filtering. The segmentation results are obtained using a maximum-flow algorithm on the graph. Then the anatomic structure is identified in thyroid ultrasound image. Finally the rendering colors on these anatomic regions are extracted and validated to find the frames which satisfy the selection criteria. To test the performance of the proposed method, a thyroid elastogram dataset is built and totally 33 cases were collected. An experienced radiologist manually evaluates the selection results of the proposed method. Experimental results demonstrate that the proposed method finds the qualified rendering frame with 100% accuracy. The proposed scheme assists the radiologists to diagnose the thyroid diseases using the qualified rendering images.

  18. On-the-fly generation and rendering of infinite cities on the GPU

    KAUST Repository

    Steinberger, Markus; Kenzel, Michael; Kainz, Bernhard K.; Wonka, Peter; Schmalstieg, Dieter

    2014-01-01

    In this paper, we present a new approach for shape-grammar-based generation and rendering of huge cities in real-time on the graphics processing unit (GPU). Traditional approaches rely on evaluating a shape grammar and storing the geometry produced as a preprocessing step. During rendering, the pregenerated data is then streamed to the GPU. By interweaving generation and rendering, we overcome the problems and limitations of streaming pregenerated data. Using our methods of visibility pruning and adaptive level of detail, we are able to dynamically generate only the geometry needed to render the current view in real-time directly on the GPU. We also present a robust and efficient way to dynamically update a scene's derivation tree and geometry, enabling us to exploit frame-to-frame coherence. Our combined generation and rendering is significantly faster than all previous work. For detailed scenes, we are capable of generating geometry more rapidly than even just copying pregenerated data from main memory, enabling us to render cities with thousands of buildings at up to 100 frames per second, even with the camera moving at supersonic speed. © 2014 The Author(s) Computer Graphics Forum © 2014 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

  19. Galvanic element. Galvanisches Element

    Energy Technology Data Exchange (ETDEWEB)

    Sprengel, D.; Haelbig, H.

    1980-01-03

    The invention concerns a gas-tight sealed accumulator with positive and negative electrode plates and an auxillary electrode electroconductively bound to the latter for suppressing oxygen pressure. The auxillary electrode is an intermediate film electrode. The film catalysing oxygen reduction is hydrophilic in character and the other film is hydrophobic. A double coated foil has proved to be advantageous, the hydrophilic film being formed from polymer-bound activated carbon and the hydrophrobic film from porous polytetrafluoroethylene. A metallic network of silver or nickel is rolled into the outer side of the activated carbon film. This auxillary electrode can be used to advantage in all galvanic elements. Even primary cells fall within the scope of application for auxillary electrodes because many of these contain a highly oxidized electrodic material which tends to give off oxygen.

  20. CRISS power spectral density

    International Nuclear Information System (INIS)

    Vaeth, W.

    1979-04-01

    The correlation of signal components at different frequencies like higher harmonics cannot be detected by a normal power spectral density measurement, since this technique correlates only components at the same frequency. This paper describes a special method for measuring the correlation of two signal components at different frequencies: the CRISS power spectral density. From this new function in frequency analysis, the correlation of two components can be determined quantitatively either they stem from one signal or from two diverse signals. The principle of the method, suitable for the higher harmonics of a signal as well as for any other frequency combinations is shown for the digital frequency analysis technique. Two examples of CRISS power spectral densities demonstrates the operation of the new method. (orig.) [de

  1. Parametric Explosion Spectral Model

    Energy Technology Data Exchange (ETDEWEB)

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  2. Real-Time Location-Based Rendering of Urban Underground Pipelines

    Directory of Open Access Journals (Sweden)

    Wei Li

    2018-01-01

    Full Text Available The concealment and complex spatial relationships of urban underground pipelines present challenges in managing them. Recently, augmented reality (AR has been a hot topic around the world, because it can enhance our perception of reality by overlaying information about the environment and its objects onto the real world. Using AR, underground pipelines can be displayed accurately, intuitively, and in real time. We analyzed the characteristics of AR and their application in underground pipeline management. We mainly focused on the AR pipeline rendering procedure based on the BeiDou Navigation Satellite System (BDS and simultaneous localization and mapping (SLAM technology. First, in aiming to improve the spatial accuracy of pipeline rendering, we used differential corrections received from the Ground-Based Augmentation System to compute the precise coordinates of users in real time, which helped us accurately retrieve and draw pipelines near the users, and by scene recognition the accuracy can be further improved. Second, in terms of pipeline rendering, we used Visual-Inertial Odometry (VIO to track the rendered objects and made some improvements to visual effects, which can provide steady dynamic tracking of pipelines even in relatively markerless environments and outdoors. Finally, we used the occlusion method based on real-time 3D reconstruction to realistically express the immersion effect of underground pipelines. We compared our methods to the existing methods and concluded that the method proposed in this research improves the spatial accuracy of pipeline rendering and the portability of the equipment. Moreover, the updating of our rendering procedure corresponded with the moving of the user’s location, thus we achieved a dynamic rendering of pipelines in the real environment.

  3. Optimization of compressive 4D-spatio-spectral snapshot imaging

    Science.gov (United States)

    Zhao, Xia; Feng, Weiyi; Lin, Lihua; Su, Wu; Xu, Guoqing

    2017-10-01

    In this paper, a modified 3D computational reconstruction method in the compressive 4D-spectro-volumetric snapshot imaging system is proposed for better sensing spectral information of 3D objects. In the design of the imaging system, a microlens array (MLA) is used to obtain a set of multi-view elemental images (EIs) of the 3D scenes. Then, these elemental images with one dimensional spectral information and different perspectives are captured by the coded aperture snapshot spectral imager (CASSI) which can sense the spectral data cube onto a compressive 2D measurement image. Finally, the depth images of 3D objects at arbitrary depths, like a focal stack, are computed by inversely mapping the elemental images according to geometrical optics. With the spectral estimation algorithm, the spectral information of 3D objects is also reconstructed. Using a shifted translation matrix, the contrast of the reconstruction result is further enhanced. Numerical simulation results verify the performance of the proposed method. The system can obtain both 3D spatial information and spectral data on 3D objects using only one single snapshot, which is valuable in the agricultural harvesting robots and other 3D dynamic scenes.

  4. Spectral analysis by correlation

    International Nuclear Information System (INIS)

    Fauque, J.M.; Berthier, D.; Max, J.; Bonnet, G.

    1969-01-01

    The spectral density of a signal, which represents its power distribution along the frequency axis, is a function which is of great importance, finding many uses in all fields concerned with the processing of the signal (process identification, vibrational analysis, etc...). Amongst all the possible methods for calculating this function, the correlation method (correlation function calculation + Fourier transformation) is the most promising, mainly because of its simplicity and of the results it yields. The study carried out here will lead to the construction of an apparatus which, coupled with a correlator, will constitute a set of equipment for spectral analysis in real time covering the frequency range 0 to 5 MHz. (author) [fr

  5. Spectral backward radiation profile

    International Nuclear Information System (INIS)

    Kwon, Sung Duck; Lee, Keun Hyun; Kim, Bo Ra; Yoon, Suk Soo

    2004-01-01

    Ultrasonic backward radiation profile is frequency-dependent when incident region has deptional gradient of acoustical properties or multi-layers. Until now, we have measured the profiles of principal frequencies of used transducers so that it was not easy to understand the change of the frequency component and spectrum of backward radiation from the profile. We tried to measure the spectral backward radiation profiles using DFP(digital filer package) Lecroy DSO. The very big changes in the shape and pattern of spectral backward radiation profiles leads to the conclusion that this new try could be very effective tool to evaluate frequency dependent surface area.

  6. 3-D volume rendering visualization for calculated distributions of diesel spray; Diesel funmu kyodo suchi keisan kekka no sanjigen volume rendering hyoji

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizaki, T; Imanishi, H; Nishida, K; Yamashita, H; Hiroyasu, H; Kaneda, K [Hiroshima University, Hiroshima (Japan)

    1997-10-01

    Three dimensional visualization technique based on volume rendering method has been developed in order to translate calculated results of diesel combustion simulation into realistically spray and flame images. This paper presents an overview of diesel combustion model which has been developed at Hiroshima University, a description of the three dimensional visualization technique, and some examples of spray and flame image generated by this visualization technique. 8 refs., 8 figs., 1 tab.

  7. Bounded elements in Locally C*-algebras

    International Nuclear Information System (INIS)

    El Harti, Rachid

    2001-09-01

    In order to get more useful information about Locally C*-algebras, we introduce in this paper the notion of bounded elements. First, we study the connection between bounded elements and spectrally bounded elements. Some structural results of Locally C*-algebras are established in Theorems 1 , 2 and 3. As an immediate consequence of Theorem 3, we give a characterization of the connected component of the identity in the group of unitary elements for a Locally C*-algebra. (author)

  8. A cache-friendly sampling strategy for texture-based volume rendering on GPU

    Directory of Open Access Journals (Sweden)

    Junpeng Wang

    2017-06-01

    Full Text Available The texture-based volume rendering is a memory-intensive algorithm. Its performance relies heavily on the performance of the texture cache. However, most existing texture-based volume rendering methods blindly map computational resources to texture memory and result in incoherent memory access patterns, causing low cache hit rates in certain cases. The distance between samples taken by threads of an atomic scheduling unit (e.g. a warp of 32 threads in CUDA of the GPU is a crucial factor that affects the texture cache performance. Based on this fact, we present a new sampling strategy, called Warp Marching, for the ray-casting algorithm of texture-based volume rendering. The effects of different sample organizations and different thread-pixel mappings in the ray-casting algorithm are thoroughly analyzed. Also, a pipeline manner color blending approach is introduced and the power of warp-level GPU operations is leveraged to improve the efficiency of parallel executions on the GPU. In addition, the rendering performance of the Warp Marching is view-independent, and it outperforms existing empty space skipping techniques in scenarios that need to render large dynamic volumes in a low resolution image. Through a series of micro-benchmarking and real-life data experiments, we rigorously analyze our sampling strategies and demonstrate significant performance enhancements over existing sampling methods.

  9. Spectral Ensemble Kalman Filters

    Czech Academy of Sciences Publication Activity Database

    Mandel, Jan; Kasanický, Ivan; Vejmelka, Martin; Fuglík, Viktor; Turčičová, Marie; Eben, Kryštof; Resler, Jaroslav; Juruš, Pavel

    2014-01-01

    Roč. 11, - (2014), EMS2014-446 [EMS Annual Meeting /14./ & European Conference on Applied Climatology (ECAC) /10./. 06.10.2014-10.10.2014, Prague] R&D Projects: GA ČR GA13-34856S Grant - others:NSF DMS-1216481 Institutional support: RVO:67985807 Keywords : data assimilation * spectral filter Subject RIV: DG - Athmosphere Sciences, Meteorology

  10. A Simple Spectral Observer

    Directory of Open Access Journals (Sweden)

    Lizeth Torres

    2018-05-01

    Full Text Available The principal aim of a spectral observer is twofold: the reconstruction of a signal of time via state estimation and the decomposition of such a signal into the frequencies that make it up. A spectral observer can be catalogued as an online algorithm for time-frequency analysis because is a method that can compute on the fly the Fourier transform (FT of a signal, without having the entire signal available from the start. In this regard, this paper presents a novel spectral observer with an adjustable constant gain for reconstructing a given signal by means of the recursive identification of the coefficients of a Fourier series. The reconstruction or estimation of a signal in the context of this work means to find the coefficients of a linear combination of sines a cosines that fits a signal such that it can be reproduced. The design procedure of the spectral observer is presented along with the following applications: (1 the reconstruction of a simple periodical signal, (2 the approximation of both a square and a triangular signal, (3 the edge detection in signals by using the Fourier coefficients, (4 the fitting of the historical Bitcoin market data from 1 December 2014 to 8 January 2018 and (5 the estimation of a input force acting upon a Duffing oscillator. To round out this paper, we present a detailed discussion about the results of the applications as well as a comparative analysis of the proposed spectral observer vis-à-vis the Short Time Fourier Transform (STFT, which is a well-known method for time-frequency analysis.

  11. Evaluation and Improvement of the CIE Metameric and Colour Rendering Index

    Directory of Open Access Journals (Sweden)

    Radovan Slavuj

    2015-12-01

    Full Text Available All artificial light sources are intended to simulate daylight and its properties of color rendering or ability of colour discrimination. Two indices, defined by the CIE, are used to quantify quality of the artificial light sources. First is Color Rendering Index which quantifies ability of light sources to render colours and other is the Metemerism Index which describes metamerism potential of given light source. Calculation of both indices are defined by CIE and has been a subject of discussion and change in past. In this work particularly, the problem of sample number and type used in calculation is addressed here and evaluated. It is noticed that both indices depends on the choice and sample number and that they should be determined based on application.

  12. The Visualization Toolkit (VTK): Rewriting the rendering code for modern graphics cards

    Science.gov (United States)

    Hanwell, Marcus D.; Martin, Kenneth M.; Chaudhary, Aashish; Avila, Lisa S.

    2015-09-01

    The Visualization Toolkit (VTK) is an open source, permissively licensed, cross-platform toolkit for scientific data processing, visualization, and data analysis. It is over two decades old, originally developed for a very different graphics card architecture. Modern graphics cards feature fully programmable, highly parallelized architectures with large core counts. VTK's rendering code was rewritten to take advantage of modern graphics cards, maintaining most of the toolkit's programming interfaces. This offers the opportunity to compare the performance of old and new rendering code on the same systems/cards. Significant improvements in rendering speeds and memory footprints mean that scientific data can be visualized in greater detail than ever before. The widespread use of VTK means that these improvements will reap significant benefits.

  13. Reflection curves—new computation and rendering techniques

    Directory of Open Access Journals (Sweden)

    Dan-Eugen Ulmet

    2004-05-01

    Full Text Available Reflection curves on surfaces are important tools for free-form surface interrogation. They are essential for industrial 3D CAD/CAM systems and for rendering purposes. In this note, new approaches regarding the computation and rendering of reflection curves on surfaces are introduced. These approaches are designed to take the advantage of the graphics libraries of recent releases of commercial systems such as the OpenInventor toolkit (developed by Silicon Graphics or Matlab (developed by The Math Works. A new relation between reflection curves and contour curves is derived; this theoretical result is used for a straightforward Matlab implementation of reflection curves. A new type of reflection curves is also generated using the OpenInventor texture and environment mapping implementations. This allows the computation, rendering, and animation of reflection curves at interactive rates, which makes it particularly useful for industrial applications.

  14. Cement-Based Renders Manufactured with Phase-Change Materials: Applications and Feasibility

    Directory of Open Access Journals (Sweden)

    Luigi Coppola

    2016-01-01

    Full Text Available The paper focuses on the evaluation of the rheological and mechanical performances of cement-based renders manufactured with phase-change materials (PCM in form of microencapsulated paraffin for innovative and ecofriendly residential buildings. Specifically, cement-based renders were manufactured by incorporating different amount of paraffin microcapsules—ranging from 5% to 20% by weight with respect to binder. Specific mass, entrained or entrapped air, and setting time were evaluated on fresh mortars. Compressive strength was measured over time to evaluate the effect of the PCM addition on the hydration kinetics of cement. Drying shrinkage was also evaluated. Experimental results confirmed that the compressive strength decreases as the amount of PCM increases. Furthermore, the higher the PCM content, the higher the drying shrinkage. The results confirm the possibility of manufacturing cement-based renders containing up to 20% by weight of PCM microcapsules with respect to binder.

  15. A concept of volume rendering guided search process to analyze medical data set.

    Science.gov (United States)

    Zhou, Jianlong; Xiao, Chun; Wang, Zhiyan; Takatsuka, Masahiro

    2008-03-01

    This paper firstly presents an approach of parallel coordinates based parameter control panel (PCP). The PCP is used to control parameters of focal region-based volume rendering (FRVR) during data analysis. It uses a parallel coordinates style interface. Different rendering parameters represented with nodes on each axis, and renditions based on related parameters are connected using polylines to show dependencies between renditions and parameters. Based on the PCP, a concept of volume rendering guided search process is proposed. The search pipeline is divided into four phases. Different parameters of FRVR are recorded and modulated in the PCP during search phases. The concept shows that volume visualization could play the role of guiding a search process in the rendition space to help users to efficiently find local structures of interest. The usability of the proposed approach is evaluated to show its effectiveness.

  16. Local intelligent electronic device (IED) rendering templates over limited bandwidth communication link to manage remote IED

    Science.gov (United States)

    Bradetich, Ryan; Dearien, Jason A; Grussling, Barry Jakob; Remaley, Gavin

    2013-11-05

    The present disclosure provides systems and methods for remote device management. According to various embodiments, a local intelligent electronic device (IED) may be in communication with a remote IED via a limited bandwidth communication link, such as a serial link. The limited bandwidth communication link may not support traditional remote management interfaces. According to one embodiment, a local IED may present an operator with a management interface for a remote IED by rendering locally stored templates. The local IED may render the locally stored templates using sparse data obtained from the remote IED. According to various embodiments, the management interface may be a web client interface and/or an HTML interface. The bandwidth required to present a remote management interface may be significantly reduced by rendering locally stored templates rather than requesting an entire management interface from the remote IED. According to various embodiments, an IED may comprise an encryption transceiver.

  17. Use of volume-rendered images in registration of nuclear medicine studies

    International Nuclear Information System (INIS)

    Wallis, J.W.; Miller, T.R.; Hsu, S.S.

    1995-01-01

    A simple operator-guided alignment technique based on volume-rendered images was developed to register tomographic nuclear medicine studies. For each of 2 three-dimensional data sets to be registered, volume-rendered images were generated in 3 orthogonal projections (x,y,z) using the method of maximum-activity projection. Registration was achieved as follows: (a) One of the rendering orientations (e.g. x) was chosen for manipulation; (b) The two dimensional rendering was translated and rotated under operator control to achieve the best alignment as determined by visual assessment; (c) This rotation and translation was then applied to the underlying three-dimensional data set, with updating of the rendered images in each of the orthogonal projections; (d) Another orientation was chosen, and the process repeated. Since manipulation was performed on the small two-dimensional rendered image, feedback was instantaneous. To aid in the visual alignment, difference images and flicker images (toggling between the two data sets) were displayed. Accuracy was assessed by analysis of separate clinical data sets acquired without patient movement. After arbitrary rotation and translation of one of the two data sets, the 2 data sets were registered. Mean registration error was 0.36 pixels, corresponding to a 2.44 mm registration error. Thus, accurate registration can be achieved in under 10 minutes using this simple technique. The accuracy of registration was assessed with use of duplicate SPECT studies originating from separate reconstructions of the data from each of the detectors of a triple-head gamma camera

  18. ACCELERATION RENDERING METHOD ON RAY TRACING WITH ANGLE COMPARISON AND DISTANCE COMPARISON

    Directory of Open Access Journals (Sweden)

    Liliana liliana

    2007-01-01

    Full Text Available In computer graphics applications, to produce realistic images, a method that is often used is ray tracing. Ray tracing does not only model local illumination but also global illumination. Local illumination count ambient, diffuse and specular effects only, but global illumination also count mirroring and transparency. Local illumination count effects from the lamp(s but global illumination count effects from other object(s too. Objects that are usually modeled are primitive objects and mesh objects. The advantage of mesh modeling is various, interesting and real-like shape. Mesh contains many primitive objects like triangle or square (rare. A problem in mesh object modeling is long rendering time. It is because every ray must be checked with a lot of triangle of the mesh. Added by ray from other objects checking, the number of ray that traced will increase. It causes the increasing of rendering time. To solve this problem, in this research, new methods are developed to make the rendering process of mesh object faster. The new methods are angle comparison and distance comparison. These methods are used to reduce the number of ray checking. The rays predicted will not intersect with the mesh, are not checked weather the ray intersects the mesh. With angle comparison, if using small angle to compare, the rendering process will be fast. This method has disadvantage, if the shape of each triangle is big, some triangles will be corrupted. If the angle to compare is bigger, mesh corruption can be avoided but the rendering time will be longer than without comparison. With distance comparison, the rendering time is less than without comparison, and no triangle will be corrupted.

  19. Construction and Evaluation of an Ultra Low Latency Frameless Renderer for VR.

    Science.gov (United States)

    Friston, Sebastian; Steed, Anthony; Tilbury, Simon; Gaydadjiev, Georgi

    2016-04-01

    Latency - the delay between a user's action and the response to this action - is known to be detrimental to virtual reality. Latency is typically considered to be a discrete value characterising a delay, constant in time and space - but this characterisation is incomplete. Latency changes across the display during scan-out, and how it does so is dependent on the rendering approach used. In this study, we present an ultra-low latency real-time ray-casting renderer for virtual reality, implemented on an FPGA. Our renderer has a latency of ~1 ms from 'tracker to pixel'. Its frameless nature means that the region of the display with the lowest latency immediately follows the scan-beam. This is in contrast to frame-based systems such as those using typical GPUs, for which the latency increases as scan-out proceeds. Using a series of high and low speed videos of our system in use, we confirm its latency of ~1 ms. We examine how the renderer performs when driving a traditional sequential scan-out display on a readily available HMO, the Oculus Rift OK2. We contrast this with an equivalent apparatus built using a GPU. Using captured human head motion and a set of image quality measures, we assess the ability of these systems to faithfully recreate the stimuli of an ideal virtual reality system - one with a zero latency tracker, renderer and display running at 1 kHz. Finally, we examine the results of these quality measures, and how each rendering approach is affected by velocity of movement and display persistence. We find that our system, with a lower average latency, can more faithfully draw what the ideal virtual reality system would. Further, we find that with low display persistence, the sensitivity to velocity of both systems is lowered, but that it is much lower for ours.

  20. USER EVALUATION OF EIGHT LED LIGHT SOURCES WITH DIFFERENTSPECIAL COLOUR RENDERING INDICES R9

    DEFF Research Database (Denmark)

    Markvart, Jakob; Iversen, Anne; Logadóttir, Ásta

    2013-01-01

    In this study we evaluated the influence of the special colour rendering index R9 on subjective red colour perception and Caucasian skin appearance among untrained test subjects. The light sources tested are commercially available LED based light sources with similar correlated colour temperature...... and general colour rendering index, but with varying R9. It was found that the test subjects in general are more positive towards light sources with higher R9. The shift from a majority of negative responses to a majority of positive responses is found to occur at R9 values of ~20....

  1. Mastering Mental Ray Rendering Techniques for 3D and CAD Professionals

    CERN Document Server

    O'Connor, Jennifer

    2010-01-01

    Proven techniques for using mental ray effectively. If you're a busy artist seeking high-end results for your 3D, design, or architecture renders using mental ray, this is the perfect book for you. It distills the highly technical nature of rendering into easy-to-follow steps and tutorials that you can apply immediately to your own projects. The book uses 3ds Max and 3ds Max Design to show the integration with mental ray, but users of any 3D or CAD software can learn valuable techniques for incorporating mental ray into their pipelines.: Takes you under the hood of mental ray, a stand-alone or

  2. Towards the Availability of the Distributed Cluster Rendering System: Automatic Modeling and Verification

    DEFF Research Database (Denmark)

    Wang, Kemin; Jiang, Zhengtao; Wang, Yongbin

    2012-01-01

    , whenever the number of node-n and related parameters vary, we can create the PRISM model file rapidly and then we can use PRISM model checker to verify ralated system properties. At the end of this study, we analyzed and verified the availability distributions of the Distributed Cluster Rendering System......In this study, we proposed a Continuous Time Markov Chain Model towards the availability of n-node clusters of Distributed Rendering System. It's an infinite one, we formalized it, based on the model, we implemented a software, which can automatically model with PRISM language. With the tool...

  3. Parametric model of the scala tympani for haptic-rendered cochlear implantation.

    Science.gov (United States)

    Todd, Catherine; Naghdy, Fazel

    2005-01-01

    A parametric model of the human scala tympani has been designed for use in a haptic-rendered computer simulation of cochlear implant surgery. It will be the first surgical simulator of this kind. A geometric model of the Scala Tympani has been derived from measured data for this purpose. The model is compared with two existing descriptions of the cochlear spiral. A first approximation of the basilar membrane is also produced. The structures are imported into a force-rendering software application for system development.

  4. Deep Exemplar 2D-3D Detection by Adapting from Real to Rendered Views

    OpenAIRE

    Massa, Francisco; Russell, Bryan; Aubry, Mathieu

    2015-01-01

    This paper presents an end-to-end convolutional neural network (CNN) for 2D-3D exemplar detection. We demonstrate that the ability to adapt the features of natural images to better align with those of CAD rendered views is critical to the success of our technique. We show that the adaptation can be learned by compositing rendered views of textured object models on natural images. Our approach can be naturally incorporated into a CNN detection pipeline and extends the accuracy and speed benefi...

  5. Digital representations of the real world how to capture, model, and render visual reality

    CERN Document Server

    Magnor, Marcus A; Sorkine-Hornung, Olga; Theobalt, Christian

    2015-01-01

    Create Genuine Visual Realism in Computer Graphics Digital Representations of the Real World: How to Capture, Model, and Render Visual Reality explains how to portray visual worlds with a high degree of realism using the latest video acquisition technology, computer graphics methods, and computer vision algorithms. It explores the integration of new capture modalities, reconstruction approaches, and visual perception into the computer graphics pipeline.Understand the Entire Pipeline from Acquisition, Reconstruction, and Modeling to Realistic Rendering and ApplicationsThe book covers sensors fo

  6. Hardware-accelerated Point Generation and Rendering of Point-based Impostors

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas

    2005-01-01

    This paper presents a novel scheme for generating points from triangle models. The method is fast and lends itself well to implementation using graphics hardware. The triangle to point conversion is done by rendering the models, and the rendering may be performed procedurally or by a black box API....... I describe the technique in detail and discuss how the generated point sets can easily be used as impostors for the original triangle models used to create the points. Since the points reside solely in GPU memory, these impostors are fairly efficient. Source code is available online....

  7. Precision spectral manipulation: A demonstration using a coherent optical memory

    Energy Technology Data Exchange (ETDEWEB)

    Sparkes, B. M.; Cairns, C.; Hosseini, M.; Higginbottom, D.; Campbell, G. T.; Lam, P. K.; Buchler, B. C. [Centre for Quantum Computation and Communication Technology, The Australian National University, Canberra (Australia)

    2014-12-04

    The ability to coherently spectrally manipulate quantum information has the potential to improve qubit rates across quantum channels and find applications in optical quantum computing. Here we present experiments that use a multi-element solenoid combined with the three-level gradient echo memory scheme to perform precision spectral manipulation of optical pulses. If applied in a quantum information network, these operations would enable frequency-based multiplexing of qubits.

  8. SPECTRAL FILTRATION OF IMAGES BY MEANS OF DISPERSIVE SYSTEMS

    Directory of Open Access Journals (Sweden)

    I. M. Gulis

    2016-01-01

    Full Text Available Instruments for spectral filtration of images are an important element of the systems used in remote sensing, medical diagnostics, in-process measurements. The aim of this study is analysis of the functional features and characteristics of the proposed two image monochromator versions which are based on dispersive spectral filtering. The first is based on the use of a dispersive monochromator, where collimating and camera lenses form a telescopic system, the dispersive element of which is within the intermediate image plane. The second version is based on an imaging double monochromator with dispersion subtraction by back propagation. For the telescopic system version, the spectral and spatial resolutions are estimated, the latter being limited by aberrations and diffraction from the entrance slit. The device has been numerically simulated and prototyped. It is shown that for the spectral bandwidth 10 nm (visible spectral range, the aberration-limited spot size is from 10–20 μm at the image center to about 30 μm at the image periphery for the image size 23–27 mm. The monochromator with dispersion subtraction enables one to vary the spectral resolution (up to 1 nm and higher by changing the intermediate slit width. But the distinctive feature is a significant change in the selected central wavelength over the image field. The considered designs of dispersive image monochromators look very promising due to the particular advantages over the systems based on tunable filters as regards the spectral resolution, fast tuning, and the spectral contrast. The monochromator based on a telescopic system has a simple design and a rather large image field but it also has a limited light throughput due to small aperture size. The monochromator with dispersion subtraction has higher light throughput, can provide high spectral resolution when recording a full data cube in a series of measuring acts for different dispersive element positions. 

  9. Elementary principles of spectral distributions

    International Nuclear Information System (INIS)

    French, J.B.

    1980-01-01

    It is a common observation that as we add particles, one by one, to a simple system, things get steadily more and more complicated. For example if the system is describable in shell-model terms, i.e., with a model space in which m particles are distributed over N single-particle states, then as long as m << N, the dimensionality increases rapidly with particle number. On the other hand, for the usual (1 + 2)-body Hamiltonian, the (m greater than or equal to 2)-particle spectrum and wave functions are determined by operators defined in the one-particle space (for the single-particle energies) and the two-particle space (for the interactions). We may say then that the input information becomes more and more fragmented as the particle number increases, the fixed amount of information being distributed over more and more matrix elements. On the other hand there arise also new simplicities whose origin is connected with the operation of statistical laws. There is a macroscopic simplicity corresponding to the fact that the smoothed spectrum takes on a characteristic shape defined by a few parameters (low-order moments) of the spectrum. There is a microscopic simplicity corresponding to a remarkable spectral rigidity which extends over the entire spectrum and guarantees us that the fluctuations from uniformity in the spectrum are small and in many cases carry little information. The purpose of spectral-distribution theory, as applied to these problems, is to deal with the complexities by taking advantage of the simplicities

  10. Hybrid spectral CT reconstruction.

    Directory of Open Access Journals (Sweden)

    Darin P Clark

    Full Text Available Current photon counting x-ray detector (PCD technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID. In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM. Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with

  11. Hybrid spectral CT reconstruction

    Science.gov (United States)

    Clark, Darin P.

    2017-01-01

    Current photon counting x-ray detector (PCD) technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID). In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM). Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with a spectral

  12. Noncommutativity from spectral flow

    Energy Technology Data Exchange (ETDEWEB)

    Heinzl, Thomas; Ilderton, Anton [School of Mathematics and Statistics, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2007-07-27

    We investigate the transition from second- to first-order systems. Quantum mechanically, this transforms configuration space into phase space and hence introduces noncommutativity in the former. This transition may be described in terms of spectral flow. Gaps in the energy or mass spectrum may become large which effectively truncates the available state space. Using both operator and path integral languages we explicitly discuss examples in quantum mechanics (light-front) quantum field theory and string theory.

  13. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    Carrier nature of speech; modulation spectrum; spectral dynamics ... the relationships between phonetic values of sounds and their short-term spectral envelopes .... the number of free parameters that need to be estimated from training data.

  14. The spectral cell method in nonlinear earthquake modeling

    Science.gov (United States)

    Giraldo, Daniel; Restrepo, Doriam

    2017-12-01

    This study examines the applicability of the spectral cell method (SCM) to compute the nonlinear earthquake response of complex basins. SCM combines fictitious-domain concepts with the spectral-version of the finite element method to solve the wave equations in heterogeneous geophysical domains. Nonlinear behavior is considered by implementing the Mohr-Coulomb and Drucker-Prager yielding criteria. We illustrate the performance of SCM with numerical examples of nonlinear basins exhibiting physically and computationally challenging conditions. The numerical experiments are benchmarked with results from overkill solutions, and using MIDAS GTS NX, a finite element software for geotechnical applications. Our findings show good agreement between the two sets of results. Traditional spectral elements implementations allow points per wavelength as low as PPW = 4.5 for high-order polynomials. Our findings show that in the presence of nonlinearity, high-order polynomials (p ≥ 3) require mesh resolutions above of PPW ≥ 10 to ensure displacement errors below 10%.

  15. Understanding Soliton Spectral Tunneling as a Spectral Coupling Effect

    DEFF Research Database (Denmark)

    Guo, Hairun; Wang, Shaofei; Zeng, Xianglong

    2013-01-01

    Soliton eigenstate is found corresponding to a dispersive phase profile under which the soliton phase changes induced by the dispersion and nonlinearity are instantaneously counterbalanced. Much like a waveguide coupler relying on a spatial refractive index profile that supports mode coupling...... between channels, here we suggest that the soliton spectral tunneling effect can be understood supported by a spectral phase coupler. The dispersive wave number in the spectral domain must have a coupler-like symmetric profile for soliton spectral tunneling to occur. We show that such a spectral coupler...

  16. Leveraging Disturbance Observer Based Torque Control for Improved Impedance Rendering with Series Elastic Actuators

    Science.gov (United States)

    Mehling, Joshua S.; Holley, James; O'Malley, Marcia K.

    2015-01-01

    The fidelity with which series elastic actuators (SEAs) render desired impedances is important. Numerous approaches to SEA impedance control have been developed under the premise that high-precision actuator torque control is a prerequisite. Indeed, the design of an inner torque compensator has a significant impact on actuator impedance rendering. The disturbance observer (DOB) based torque control implemented in NASA's Valkyrie robot is considered here and a mathematical model of this torque control, cascaded with an outer impedance compensator, is constructed. While previous work has examined the impact a disturbance observer has on torque control performance, little has been done regarding DOBs and impedance rendering accuracy. Both simulation and a series of experiments are used to demonstrate the significant improvements possible in an SEA's ability to render desired dynamic behaviors when utilizing a DOB. Actuator transparency at low impedances is improved, closed loop hysteresis is reduced, and the actuator's dynamic response to both commands and interaction torques more faithfully matches that of the desired model. All of this is achieved by leveraging DOB based control rather than increasing compensator gains, thus making improved SEA impedance control easier to achieve in practice.

  17. Photometric and Colorimeric Comparison of HDR and Spctrally Resolved Rendering Images

    DEFF Research Database (Denmark)

    Amdemeskel, Mekbib Wubishet; Soreze, Thierry Silvio Claude; Thorseth, Anders

    2017-01-01

    In this paper, we will demonstrate a comparison between measured colorimetric images, and simulated images from a physics based rendering engine. The colorimetric images are high dynamic range (HDR) and taken with a luminance and colour camera mounted on a goniometer. For the comparison, we have ...

  18. GRAPHICS-IMAGE MIXED METHOD FOR LARGE-SCALE BUILDINGS RENDERING

    Directory of Open Access Journals (Sweden)

    Y. Zhou

    2018-05-01

    Full Text Available Urban 3D model data is huge and unstructured, LOD and Out-of-core algorithm are usually used to reduce the amount of data that drawn in each frame to improve the rendering efficiency. When the scene is large enough, even the complex optimization algorithm is difficult to achieve better results. Based on the traditional study, a novel idea was developed. We propose a graphics and image mixed method for large-scale buildings rendering. Firstly, the view field is divided into several regions, the graphics-image mixed method used to render the scene on both screen and FBO, then blending the FBO with scree. The algorithm is tested on the huge CityGML model data in the urban areas of New York which contained 188195 public building models, and compared with the Cesium platform. The experiment result shows the system was running smoothly. The experimental results confirm that the algorithm can achieve more massive building scene roaming under the same hardware conditions, and can rendering the scene without vision loss.

  19. Advanced Audiovisual Rendering, Gesture-Based Interaction and Distributed Delivery for Immersive and Interactive Media Services

    NARCIS (Netherlands)

    Niamut, O.A.; Kochale, A.; Ruiz Hidalgo, J.; Macq, J-F.; Kienast, G.

    2011-01-01

    The media industry is currently being pulled in the often-opposing directions of increased realism (high resolution, stereoscopic, large screen) and personalisation (selection and control of content, availability on many devices). A capture, production, delivery and rendering system capable of

  20. An economic analysis of localized pollution: rendering emissions in a residential setting

    Science.gov (United States)

    J. Michael Bowker; H.F. MacDonald

    1991-01-01

    The contingent value method is employed to estimate economic damages to households resulting from rendering plant emissions in a small town. Household willingness to accept (WTA) and willingness to pay (WTP) are estimated individually and in aggregate. The influence of household characteristics on WTP and WTA is examined via regression models. The perception of health...

  1. 3D-TV Rendering on a Multiprocessor System on a Chip

    NARCIS (Netherlands)

    Van Eijndhoven, J.T.J.; Li, X.

    2006-01-01

    This thesis focuses on the issue of mapping 3D-TV rendering applications to a multiprocessor platform. The target platform aims to address tomorrow's multi-media consumer market. The prototype chip, called Wasabi, contains a set of TriMedia processors that communicate viaa shared memory, fast

  2. Dynamic Resolution in GPU-Accelerated Volume Rendering to Autostereoscopic Multiview Lenticular Displays

    Directory of Open Access Journals (Sweden)

    Daniel Ruijters

    2008-09-01

    Full Text Available The generation of multiview stereoscopic images of large volume rendered data demands an enormous amount of calculations. We propose a method for hardware accelerated volume rendering of medical data sets to multiview lenticular displays, offering interactive manipulation throughout. The method is based on buffering GPU-accelerated direct volume rendered visualizations of the individual views from their respective focal spot positions, and composing the output signal for the multiview lenticular screen in a second pass. This compositing phase is facilitated by the fact that the view assignment per subpixel is static, and therefore can be precomputed. We decoupled the resolution of the individual views from the resolution of the composited signal, and adjust the resolution on-the-fly, depending on the available processing resources, in order to maintain interactive refresh rates. The optimal resolution for the volume rendered views is determined by means of an analysis of the lattice of the output signal for the lenticular screen in the Fourier domain.

  3. An Extension of Fourier-Wavelet Volume Rendering by View Interpolation

    NARCIS (Netherlands)

    Westenberg, Michel A.; Roerdink, Jos B.T.M.

    2001-01-01

    This paper describes an extension to Fourier-wavelet volume rendering (FWVR), which is a Fourier domain implementation of the wavelet X-ray transform. This transform combines integration along the line of sight with a simultaneous 2-D wavelet transform in the view plane perpendicular to this line.

  4. User evaluation of eight led light sources with different special colour rendering indices R9

    DEFF Research Database (Denmark)

    Markvart, Jakob; Iversen, Anne; Logadottir, Asta

    2013-01-01

    In this study we evaluated the influence of the special colour rendering index R9 on subjective red colour perception and Caucasian skin appearance among untrained test subjects. The light sources tested are commercially available LED based light sources with similar correlated colour temperature...

  5. Uniform illumination rendering using an array of LEDs: a signal processing perspective

    NARCIS (Netherlands)

    Yang, Hongming; Bergmans, J.W.M.; Schenk, T.C.W.; Linnartz, J.P.M.G.; Rietman, R.

    2009-01-01

    An array of a large number of LEDs will be widely used in future indoor illumination systems. In this paper, we investigate the problem of rendering uniform illumination by a regular LED array on the ceiling of a room. We first present two general results on the scaling property of the basic

  6. Incompressible spectral-element method: Derivation of equations

    Science.gov (United States)

    Deanna, Russell G.

    1993-01-01

    A fractional-step splitting scheme breaks the full Navier-Stokes equations into explicit and implicit portions amenable to the calculus of variations. Beginning with the functional forms of the Poisson and Helmholtz equations, we substitute finite expansion series for the dependent variables and derive the matrix equations for the unknown expansion coefficients. This method employs a new splitting scheme which differs from conventional three-step (nonlinear, pressure, viscous) schemes. The nonlinear step appears in the conventional, explicit manner, the difference occurs in the pressure step. Instead of solving for the pressure gradient using the nonlinear velocity, we add the viscous portion of the Navier-Stokes equation from the previous time step to the velocity before solving for the pressure gradient. By combining this 'predicted' pressure gradient with the nonlinear velocity in an explicit term, and the Crank-Nicholson method for the viscous terms, we develop a Helmholtz equation for the final velocity.

  7. Wavelet Spectral Finite Elements for Wave Propagation in Composite Plates

    Science.gov (United States)

    2012-02-21

    aerospace structures is increasing rapidly due to several advantages such as lighter weight, fewer joints, improved fatigue life, and higher...breakage, and matrix cracking. These damages often occur below the surface due to fatigue , foreign object impact, etc., and may not be visible. The...ply [0/90]2s. A piezoelectric ( PZT ) actuator (diameter 13.5 mm and thickness 0.22 mm) is affixed onto the composite plate using epoxy. A National

  8. Nonconforming hp spectral element methods for elliptic problems

    Indian Academy of Sciences (India)

    Geometrical mesh; stability estimate; least-squares solution; preconditioners; condition numbers; exponential accuracy. ... Department of Mathematics, Indian Institute of Technology Kanpur, Kanpur 208 016, India; Department of Aerospace Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016, India ...

  9. Interactive dual-volume rendering visualization with real-time fusion and transfer function enhancement

    Science.gov (United States)

    Macready, Hugh; Kim, Jinman; Feng, David; Cai, Weidong

    2006-03-01

    Dual-modality imaging scanners combining functional PET and anatomical CT constitute a challenge in volumetric visualization that can be limited by the high computational demand and expense. This study aims at providing physicians with multi-dimensional visualization tools, in order to navigate and manipulate the data running on a consumer PC. We have maximized the utilization of pixel-shader architecture of the low-cost graphic hardware and the texture-based volume rendering to provide visualization tools with high degree of interactivity. All the software was developed using OpenGL and Silicon Graphics Inc. Volumizer, tested on a Pentium mobile CPU on a PC notebook with 64M graphic memory. We render the individual modalities separately, and performing real-time per-voxel fusion. We designed a novel "alpha-spike" transfer function to interactively identify structure of interest from volume rendering of PET/CT. This works by assigning a non-linear opacity to the voxels, thus, allowing the physician to selectively eliminate or reveal information from the PET/CT volumes. As the PET and CT are rendered independently, manipulations can be applied to individual volumes, for instance, the application of transfer function to CT to reveal the lung boundary while adjusting the fusion ration between the CT and PET to enhance the contrast of a tumour region, with the resultant manipulated data sets fused together in real-time as the adjustments are made. In addition to conventional navigation and manipulation tools, such as scaling, LUT, volume slicing, and others, our strategy permits efficient visualization of PET/CT volume rendering which can potentially aid in interpretation and diagnosis.

  10. Validation of Thermal Lethality against Salmonella enterica in Poultry Offal during Rendering.

    Science.gov (United States)

    Jones-Ibarra, Amie-Marie; Acuff, Gary R; Alvarado, Christine Z; Taylor, T Matthew

    2017-09-01

    Recent outbreaks of human disease following contact with companion animal foods cross-contaminated with enteric pathogens, such as Salmonella enterica, have resulted in increased concern regarding the microbiological safety of animal foods. Additionally, the U.S. Food and Drug Administration Food Safety Modernization Act and its implementing rules have stipulated the implementation of current good manufacturing practices and food safety preventive controls for livestock and companion animal foods. Animal foods and feeds are sometimes formulated to include thermally rendered animal by-product meals. The objective of this research was to determine the thermal inactivation of S. enterica in poultry offal during rendering at differing temperatures. Raw poultry offal was obtained from a commercial renderer and inoculated with a mixture of Salmonella serovars Senftenberg, Enteritidis, and Gallinarum (an avian pathogen) prior to being subjected to heating at 150, 155, or 160°F (65.5, 68.3, or 71.1°C) for up to 15 min. Following heat application, surviving Salmonella bacteria were enumerated. Mean D-values for the Salmonella cocktail at 150, 155, and 160°F were 0.254 ± 0.045, 0.172 ± 0.012, and 0.086 ± 0.004 min, respectively, indicative of increasing susceptibility to increased application of heat during processing. The mean thermal process constant (z-value) was 21.948 ± 3.87°F. Results indicate that a 7.0-log-cycle inactivation of Salmonella may be obtained from the cumulative lethality encountered during the heating come-up period and subsequent rendering of raw poultry offal at temperatures not less than 150°F. Current poultry rendering procedures are anticipated to be effective for achieving necessary pathogen control when completed under sanitary conditions.

  11. Developing a Tile-Based Rendering Method to Improve Rendering Speed of 3D Geospatial Data with HTML5 and WebGL

    Directory of Open Access Journals (Sweden)

    Seokchan Kang

    2017-01-01

    Full Text Available A dedicated plug-in has been installed to visualize three-dimensional (3D city modeling spatial data in web-based applications. However, plug-in methods are gradually becoming obsolete, owing to their limited performance with respect to installation errors, unsupported cross-browsers, and security vulnerability. Particularly, in 2015, the NPAPI service was terminated in most existing web browsers except Internet Explorer. To overcome these problems, the HTML5/WebGL (next-generation web standard, confirmed in October 2014 technology emerged. In particular, WebGL is able to display 3D spatial data without plug-ins in browsers. In this study, we attempted to identify the requirements and limitations of displaying 3D city modeling spatial data using HTML5/WebGL, and we propose alternative ways based on the bin-packing algorithm that aggregates individual 3D city modeling data including buildings in tile units. The proposed method reduces the operational complexity and the number and volume of transmissions required for rendering processing to improve the speed of 3D data rendering. The proposed method was validated on real data for evaluating its effectiveness in 3D visualization of city modeling data in web-based applications.

  12. Transplutonium elements

    Energy Technology Data Exchange (ETDEWEB)

    Sivaramakrishnan, C. K.; Jadhav, A. V.; Reghuraman, K.; Mathew, K. A.; Nair, P. S.; Ramaniah, M. V.

    1973-07-01

    Research progress is reported on studies of the transplutonium elements including recovery and purification of americium, preparation of /sup 238/Pu, extraction studies using diethylhexyl phosphate. (DHM)

  13. VIDEO ANIMASI 3D PENGENALAN RUMAH ADAT DAN ALAT MUSIK KEPRI DENGAN MENGUNAKAN TEKNIK RENDER CEL-SHADING

    OpenAIRE

    Jianfranco Irfian Asnawi; Afdhol Dzikri

    2016-01-01

    Animasi ini berjudul "video animasi 3D rumah adat dan alat musik Kepulauan Riau dengan menggunakan teknik render cel-shading" merupakan video yang bertujuan memperkenalkan alat-alat musik yang berasal dari kepulauan riau, Animasi ini akan diterapkan dengan menggunakan teknik render cel-shading. Cel-shading adalah teknik render yang menampilkan grafik 3D yang menyerupai gambar tangan, seperti gambar komik dan kartun. Teknik ini juga sudah di terapkan dalam game 3D yang ternyata menarik banyak ...

  14. Spectral dispersion and fringe detection in IOTA

    Science.gov (United States)

    Traub, W. A.; Lacasse, M. G.; Carleton, N. P.

    1990-01-01

    Pupil plane beam combination, spectral dispersion, detection, and fringe tracking are discussed for the IOTA interferometer. A new spectrometer design is presented in which the angular dispersion with respect to wavenumber is nearly constant. The dispersing element is a type of grism, a series combination of grating and prism, in which the constant parts of the dispersion add, but the slopes cancel. This grism is optimized for the display of channelled spectra. The dispersed fringes can be tracked by a matched-filter photon-counting correlator algorithm. This algorithm requires very few arithmetic operations per detected photon, making it well-suited for real-time fringe tracking. The algorithm is able to adapt to different stellar spectral types, intensity levels, and atmospheric time constants. The results of numerical experiments are reported.

  15. Spectral signature selection for mapping unvegetated soils

    Science.gov (United States)

    May, G. A.; Petersen, G. W.

    1975-01-01

    Airborne multispectral scanner data covering the wavelength interval from 0.40-2.60 microns were collected at an altitude of 1000 m above the terrain in southeastern Pennsylvania. Uniform training areas were selected within three sites from this flightline. Soil samples were collected from each site and a procedure developed to allow assignment of scan line and element number from the multispectral scanner data to each sampling location. These soil samples were analyzed on a spectrophotometer and laboratory spectral signatures were derived. After correcting for solar radiation and atmospheric attenuation, the laboratory signatures were compared to the spectral signatures derived from these same soils using multispectral scanner data. Both signatures were used in supervised and unsupervised classification routines. Computer-generated maps using the laboratory and multispectral scanner derived signatures resulted in maps that were similar to maps resulting from field surveys. Approximately 90% agreement was obtained between classification maps produced using multispectral scanner derived signatures and laboratory derived signatures.

  16. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Doshi, P.K.; George, R.A.; Dollard, W.J.

    1982-01-01

    A mechanical spectral shift arrangement for controlling a nuclear reactor includes a plurality of reactor coolant displacer members which are inserted into a reactor core at the beginning of the core life to reduce the volume of reactor coolant-moderator in the core at start-up. However, as the reactivity of the core declines with fuel depletion, selected displacer members are withdrawn from the core at selected time intervals to increase core moderation at a time when fuel reactivity is declining. (author)

  17. Spectral signatures of chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We present a new way of measuring chirality, via the spectral shift of photonic band gaps in one-dimensional structures. We derive an explicit mapping of the problem of oblique incidence of circularly polarized light on a chiral one-dimensional photonic crystal with negligible index contrast...... to the formally equivalent problem of linearly polarized light incident on-axis on a non-chiral structure with index contrast. We derive analytical expressions for the first-order shifts of the band gaps for negligible index contrast. These are modified to give good approximations to the band gap shifts also...

  18. Spectral theory of linear operators and spectral systems in Banach algebras

    CERN Document Server

    Müller, Vladimir

    2003-01-01

    This book is dedicated to the spectral theory of linear operators on Banach spaces and of elements in Banach algebras. It presents a survey of results concerning various types of spectra, both of single and n-tuples of elements. Typical examples are the one-sided spectra, the approximate point, essential, local and Taylor spectrum, and their variants. The theory is presented in a unified, axiomatic and elementary way. Many results appear here for the first time in a monograph. The material is self-contained. Only a basic knowledge of functional analysis, topology, and complex analysis is assumed. The monograph should appeal both to students who would like to learn about spectral theory and to experts in the field. It can also serve as a reference book. The present second edition contains a number of new results, in particular, concerning orbits and their relations to the invariant subspace problem. This book is dedicated to the spectral theory of linear operators on Banach spaces and of elements in Banach alg...

  19. Toxic Elements

    DEFF Research Database (Denmark)

    Hajeb, Parvaneh; Shakibazadeh, Shahram; Sloth, Jens Jørgen

    2016-01-01

    Food is considered the main source of toxic element (arsenic, cadmium, lead, and mercury) exposure to humans, and they can cause major public health effects. In this chapter, we discuss the most important sources for toxic element in food and the foodstuffs which are significant contributors to h...

  20. Intensity Conserving Spectral Fitting

    Science.gov (United States)

    Klimchuk, J. A.; Patsourakos, S.; Tripathi, D.

    2015-01-01

    The detailed shapes of spectral line profiles provide valuable information about the emitting plasma, especially when the plasma contains an unresolved mixture of velocities, temperatures, and densities. As a result of finite spectral resolution, the intensity measured by a spectrometer is the average intensity across a wavelength bin of non-zero size. It is assigned to the wavelength position at the center of the bin. However, the actual intensity at that discrete position will be different if the profile is curved, as it invariably is. Standard fitting routines (spline, Gaussian, etc.) do not account for this difference, and this can result in significant errors when making sensitive measurements. Detection of asymmetries in solar coronal emission lines is one example. Removal of line blends is another. We have developed an iterative procedure that corrects for this effect. It can be used with any fitting function, but we employ a cubic spline in a new analysis routine called Intensity Conserving Spline Interpolation (ICSI). As the name implies, it conserves the observed intensity within each wavelength bin, which ordinary fits do not. Given the rapid convergence, speed of computation, and ease of use, we suggest that ICSI be made a standard component of the processing pipeline for spectroscopic data.

  1. Custom OpenStreetMap Rendering – OpenTrackMap Experience

    Directory of Open Access Journals (Sweden)

    Radek Bartoň

    2010-02-01

    Full Text Available After 5 years of its existence, the OpenSteetMap [1] is becoming to be an important and valuable source of a geographic data for all people on the world. Although initially targeted to provide a map of cities for routing services, it can be exploited to other and often unexpected purposes. Such an utilization is an effort to map a network of hiking tracks of the Czech Tourist Club [2].  To support and apply this endeavour, the OpenTrackMap [3] project was started. Its aim is to primarily provide a customized rendering style for Mapnik renderer which emphasizes map features important to tourists and displays a layer with hiking tracks. This article presents obstacles which such project must face and it can be used as a tutorial for other projects of similar type.

  2. Rendering LGBTQ+ Visible in Nursing: Embodying the Philosophy of Caring Science.

    Science.gov (United States)

    Goldberg, Lisa; Rosenburg, Neal; Watson, Jean

    2017-06-01

    Although health care institutions continue to address the importance of diversity initiatives, the standard(s) for treatment remain historically and institutionally grounded in a sociocultural privileging of heterosexuality. As a result, lesbian, gay, bisexual, transgender, and queer (LGBTQ+) communities in health care remain largely invisible. This marked invisibility serves as a call to action, a renaissance of thinking within redefined boundaries and limitations. We must therefore refocus our habits of attention on the wholeness of persons and the diversity of their storied experiences as embodied through contemporary society. By rethinking current understandings of LGBTQ+ identities through innovative representation(s) of the media, music industry, and pop culture within a caring science philosophy, nurses have a transformative opportunity to render LGBTQ+ visible and in turn render a transformative opportunity for themselves.

  3. 3D virtual rendering in thoracoscopic treatment of congenital malformation of the lung

    Directory of Open Access Journals (Sweden)

    Destro F.

    2013-10-01

    Full Text Available Introduction: Congenital malformations of the lung (CML are rare but potentially dangerous congenital malformations. Their identification is important in order to define the most appropriate management. Materials and methods: We retrospectively reviewed data from 37 patients affected by CML treated in our Pediatric Surgery Unit in the last four years with minimally invasive surgery (MIS. Results: Prenatal diagnosis was possible in 26/37 patients. Surgery was performed in the first month of life in 3 symptomatic patients and between 6 and 12 months in the others. All patients underwent radiological evaluation prior to thoracoscopic surgery. Images collected were reconstructed using the VR render software. Discussion and conclusions: Volume rendering gives high anatomical resolution and it can be useful to guide the surgical procedure. Thoracoscopy should be the technique of choice because it is safe, effective and feasible. Furthermore it has the benefit of a minimal access technique and it can be easily performed in children.

  4. Volume-Rendered 3D Display Of MR Angiograms in the Diagnosis of Cerebral Arteriovenous Malformations

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, K.; Katase, S.; Hachiya, J. [Kyorin Univ. School of Medicine, Tokyo (Japan). Dept. of Radiology; Shiokawa, Y. [Kyorin Univ. School of Medicine, Tokyo (Japan). Dept. of Neurosurgery

    2003-11-01

    Purpose: To determine whether application of a volume-rendered display of 3D time-of-flight (TOF) MR angiography could assist the diagnosis of cerebral arteriovenous malformations (AVMs). Material and Methods: Volume-rendered 3D images of postcontrast 3D time-of-flight MR angiography were compared with conventional angiograms in 12 patients. The correlation between the 3D images and the operative findings was also analyzed in 5 patients. Results: The 3D-displayed images showed all of the feeders and drainers in 10 and 9 patients, respectively. In all patients, the nidus was three-dimensionally visualized. In 3 patients with hematomas, the relationship between the hematoma and the AVM was well demonstrated. The 3D images corresponded well with the operative findings in the 5 patients. Conclusion: This method is of help in assessing the relationship between the components of an AVM as well as that between an AVM and an associated hematoma.

  5. Volume-Rendered 3D Display Of MR Angiograms in the Diagnosis of Cerebral Arteriovenous Malformations

    International Nuclear Information System (INIS)

    Tsuchiya, K.; Katase, S.; Hachiya, J.; Shiokawa, Y.

    2003-01-01

    Purpose: To determine whether application of a volume-rendered display of 3D time-of-flight (TOF) MR angiography could assist the diagnosis of cerebral arteriovenous malformations (AVMs). Material and Methods: Volume-rendered 3D images of postcontrast 3D time-of-flight MR angiography were compared with conventional angiograms in 12 patients. The correlation between the 3D images and the operative findings was also analyzed in 5 patients. Results: The 3D-displayed images showed all of the feeders and drainers in 10 and 9 patients, respectively. In all patients, the nidus was three-dimensionally visualized. In 3 patients with hematomas, the relationship between the hematoma and the AVM was well demonstrated. The 3D images corresponded well with the operative findings in the 5 patients. Conclusion: This method is of help in assessing the relationship between the components of an AVM as well as that between an AVM and an associated hematoma

  6. Pyrite: A blender plugin for visualizing molecular dynamics simulations using industry-standard rendering techniques.

    Science.gov (United States)

    Rajendiran, Nivedita; Durrant, Jacob D

    2018-05-05

    Molecular dynamics (MD) simulations provide critical insights into many biological mechanisms. Programs such as VMD, Chimera, and PyMOL can produce impressive simulation visualizations, but they lack many advanced rendering algorithms common in the film and video-game industries. In contrast, the modeling program Blender includes such algorithms but cannot import MD-simulation data. MD trajectories often require many gigabytes of memory/disk space, complicating Blender import. We present Pyrite, a Blender plugin that overcomes these limitations. Pyrite allows researchers to visualize MD simulations within Blender, with full access to Blender's cutting-edge rendering techniques. We expect Pyrite-generated images to appeal to students and non-specialists alike. A copy of the plugin is available at http://durrantlab.com/pyrite/, released under the terms of the GNU General Public License Version 3. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  7. Moisture transport properties of brick – comparison of exposed, impregnated and rendered brick

    DEFF Research Database (Denmark)

    Hansen, Tessa Kvist; Bjarløv, Søren Peter; Peuhkuri, Ruut

    2016-01-01

    In regards to internal insulation of preservation worthy brick façades, external moisture sources, such as wind-driven rain exposure, inevitably has an impact on moisture conditions within the masonry construction. Surface treatments, such as hydrophobation or render, may remedy the impacts...... of external moisture. In the present paper the surface absorption of liquid water on masonry façades of untreated, hydrophobated and rendered brick, are determined experimentally and compared. The experimental work focuses on methods that can be applied on-site, Karsten tube measurements. These measurements...... are supplemented with results from laboratory measurements of water absorption coefficient by partial immersion. Based on obtained measurement results, simulations are made with external liquid water loads for determination of moisture conditions within the masonry of different surface treatments. Experimental...

  8. Waqf as a Tool for Rendering Social Welfare Services in the Social Entrepreneurship Context

    Directory of Open Access Journals (Sweden)

    Md. Mahmudul Alam

    2018-01-01

    Full Text Available The concept of Islamic entrepreneurship centers on ensuring community well-being as the priority, which is one of the important objectives (Maqasid of the Islamic Shari’ah. Historically, waqf played a significant role in the Islamic economic system, particularly in rendering exemplary welfare services in the areas of healthcare, education, social welfare, environmental, and other community-based programs. However, only a few success stories in recent history have institutionally utilized the properties of waqf under proper management to achieve its substantial objectives. This study uses the literature review as basis to analyze the reasons behind the successful utilization of waqf as an effective tool to ensure social welfare services in the past, as well as how this model can be replicated by considering current contexts. This study will assist Islamic valuecentric entrepreneurs, regulatory authorities, investors, and researchers to gain an overall insight into the potentials of waqf as a tool for rendering commendable social welfare services.

  9. Apparatus for rendering at least a portion of a device inoperable and related methods

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, Michael A.; Steffler, Eric D.; Hartenstein, Steven D.; Wallace, Ronald S.

    2016-11-08

    Apparatus for rendering at least a portion of a device inoperable may include a containment structure having a first compartment that is configured to receive a device therein and a movable member configured to receive a cartridge having reactant material therein. The movable member is configured to be inserted into the first compartment of the containment structure and to ignite the reactant material within the cartridge. Methods of rendering at least a portion of a device inoperable may include disposing the device into the first compartment of the containment structure, inserting the movable member into the first compartment of the containment structure, igniting the reactant material in the cartridge, and expelling molten metal onto the device.

  10. Subsurface Scattering-Based Object Rendering Techniques for Real-Time Smartphone Games

    Directory of Open Access Journals (Sweden)

    Won-Sun Lee

    2014-01-01

    Full Text Available Subsurface scattering that simulates the path of a light through the material in a scene is one of the advanced rendering techniques in the field of computer graphics society. Since it takes a number of long operations, it cannot be easily implemented in real-time smartphone games. In this paper, we propose a subsurface scattering-based object rendering technique that is optimized for smartphone games. We employ our subsurface scattering method that is utilized for a real-time smartphone game. And an example game is designed to validate how the proposed method can be operated seamlessly in real time. Finally, we show the comparison results between bidirectional reflectance distribution function, bidirectional scattering distribution function, and our proposed subsurface scattering method on a smartphone game.

  11. A Semi-automated Approach to Improve the Efficiency of Medical Imaging Segmentation for Haptic Rendering.

    Science.gov (United States)

    Banerjee, Pat; Hu, Mengqi; Kannan, Rahul; Krishnaswamy, Srinivasan

    2017-08-01

    The Sensimmer platform represents our ongoing research on simultaneous haptics and graphics rendering of 3D models. For simulation of medical and surgical procedures using Sensimmer, 3D models must be obtained from medical imaging data, such as magnetic resonance imaging (MRI) or computed tomography (CT). Image segmentation techniques are used to determine the anatomies of interest from the images. 3D models are obtained from segmentation and their triangle reduction is required for graphics and haptics rendering. This paper focuses on creating 3D models by automating the segmentation of CT images based on the pixel contrast for integrating the interface between Sensimmer and medical imaging devices, using the volumetric approach, Hough transform method, and manual centering method. Hence, automating the process has reduced the segmentation time by 56.35% while maintaining the same accuracy of the output at ±2 voxels.

  12. A Practical Framework for Sharing and Rendering Real-World Bidirectional Scattering Distribution Functions

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Greg [Anywhere Software, Albany, CA (United States); Kurt, Murat [International Computer Institute, Ege University (Turkey); Bonneel, Nicolas [Harvard Univ., Cambridge, MA (United States)

    2012-09-30

    The utilization of real-world materials has been hindered by a lack of standards for sharing and interpreting measured data. This paper presents an XML representation and an Open Source C library to support bidirectional scattering distribution functions (BSDFs) in data-driven lighting simulation and rendering applications.The library provides for the efficient representation, query, and Monte Carlo sampling of arbitrary BSDFs in amodel-free framework. Currently, we support two BSDF data representations: one using a fixed subdivision of thehemisphere, and one with adaptive density. The fixed type has advantages for certain matrix operations, while theadaptive type can more accurately represent highly peaked data. We discuss advanced methods for data-drivenBSDF rendering for both types, including the proxy of detailed geometry to enhance appearance and accuracy.We also present an advanced interpolation method to reduce measured data into these standard representations.We end with our plan for future extensions and sharing of BSDF data.

  13. Detection of Prion Proteins and TSE Infectivity in the Rendering and Biodiesel Manufacture Processes

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.; Keller, B.; Oleschuk, R. [Queen' s University, Kingston, Ontario (Canada)

    2007-03-15

    This paper addresses emerging issues related to monitoring prion proteins and TSE infectivity in the products and waste streams of rendering and biodiesel manufacture processes. Monitoring is critical to addressing the knowledge gaps identified in 'Biodiesel from Specified Risk Material Tallow: An Appraisal of TSE Risks and their Reduction' (IEA's AMF Annex XXX, 2006) that prevent comprehensive risk assessment of TSE infectivity in products and waste. The most important challenge for monitoring TSE risk is the wide variety of sample types, which are generated at different points in the rendering/biodiesel production continuum. Conventional transmissible spongiform encephalopathy (TSE) assays were developed for specified risk material (SRM) and other biological tissues. These, however, are insufficient to address the diverse sample matrices produced in rendering and biodiesel manufacture. This paper examines the sample types expected in rendering and biodiesel manufacture and the implications of applying TSE assay methods to them. The authors then discuss a sample preparation filtration, which has not yet been applied to these sample types, but which has the potential to provide or significantly improve TSE monitoring. The main improvement will come from transfer of the prion proteins from the sample matrix to a matrix compatible with conventional and emerging bioassays. A second improvement will come from preconcentrating the prion proteins, which means transferring proteins from a larger sample volume into a smaller volume for analysis to provide greater detection sensitivity. This filtration method may also be useful for monitoring other samples, including wash waters and other waste streams, which may contain SRM, including those from abattoirs and on-farm operations. Finally, there is a discussion of emerging mass spectrometric methods, which Prusiner and others have shown to be suitable for detection and characterisation of prion proteins (Stahl

  14. LOD 1 VS. LOD 2 - Preliminary Investigations Into Differences in Mobile Rendering Performance

    Science.gov (United States)

    Ellul, C.; Altenbuchner, J.

    2013-09-01

    The increasing availability, size and detail of 3D City Model datasets has led to a challenge when rendering such data on mobile devices. Understanding the limitations to the usability of such models on these devices is particularly important given the broadening range of applications - such as pollution or noise modelling, tourism, planning, solar potential - for which these datasets and resulting visualisations can be utilized. Much 3D City Model data is created by extrusion of 2D topographic datasets, resulting in what is known as Level of Detail (LoD) 1 buildings - with flat roofs. However, in the UK the National Mapping Agency (the Ordnance Survey, OS) is now releasing test datasets to Level of Detail (LoD) 2 - i.e. including roof structures. These datasets are designed to integrate with the LoD 1 datasets provided by the OS, and provide additional detail in particular on larger buildings and in town centres. The availability of such integrated datasets at two different Levels of Detail permits investigation into the impact of the additional roof structures (and hence the display of a more realistic 3D City Model) on rendering performance on a mobile device. This paper describes preliminary work carried out to investigate this issue, for the test area of the city of Sheffield (in the UK Midlands). The data is stored in a 3D spatial database as triangles and then extracted and served as a web-based data stream which is queried by an App developed on the mobile device (using the Android environment, Java and OpenGL for graphics). Initial tests have been carried out on two dataset sizes, for the city centre and a larger area, rendering the data onto a tablet to compare results. Results of 52 seconds for rendering LoD 1 data, and 72 seconds for LoD 1 mixed with LoD 2 data, show that the impact of LoD 2 is significant.

  15. FluoRender: joint freehand segmentation and visualization for many-channel fluorescence data analysis.

    Science.gov (United States)

    Wan, Yong; Otsuna, Hideo; Holman, Holly A; Bagley, Brig; Ito, Masayoshi; Lewis, A Kelsey; Colasanto, Mary; Kardon, Gabrielle; Ito, Kei; Hansen, Charles

    2017-05-26

    Image segmentation and registration techniques have enabled biologists to place large amounts of volume data from fluorescence microscopy, morphed three-dimensionally, onto a common spatial frame. Existing tools built on volume visualization pipelines for single channel or red-green-blue (RGB) channels have become inadequate for the new challenges of fluorescence microscopy. For a three-dimensional atlas of the insect nervous system, hundreds of volume channels are rendered simultaneously, whereas fluorescence intensity values from each channel need to be preserved for versatile adjustment and analysis. Although several existing tools have incorporated support of multichannel data using various strategies, the lack of a flexible design has made true many-channel visualization and analysis unavailable. The most common practice for many-channel volume data presentation is still converting and rendering pseudosurfaces, which are inaccurate for both qualitative and quantitative evaluations. Here, we present an alternative design strategy that accommodates the visualization and analysis of about 100 volume channels, each of which can be interactively adjusted, selected, and segmented using freehand tools. Our multichannel visualization includes a multilevel streaming pipeline plus a triple-buffer compositing technique. Our method also preserves original fluorescence intensity values on graphics hardware, a crucial feature that allows graphics-processing-unit (GPU)-based processing for interactive data analysis, such as freehand segmentation. We have implemented the design strategies as a thorough restructuring of our original tool, FluoRender. The redesign of FluoRender not only maintains the existing multichannel capabilities for a greatly extended number of volume channels, but also enables new analysis functions for many-channel data from emerging biomedical-imaging techniques.

  16. An image-based approach to the rendering of crowds in real-time

    OpenAIRE

    Tecchia, Franco

    2007-01-01

    The wide use of computer graphics in games, entertainment, medical, architectural and cultural applications, has led it to becoming a prevalent area of research. Games and entertainment in general have become one of the driving forces of the real-time computer graphics industry, bringing reasonably realistic, complex and appealing virtual worlds to the mass-market. At the current stage of technology, an user can interactively navigate through complex, polygon-based scenes rendered with sophis...

  17. Efficient Algorithms for Real-Time GPU Volumetric Cloud Rendering with Enhanced Geometry

    OpenAIRE

    Carlos Jiménez de Parga; Sebastián Rubén Gómez Palomo

    2018-01-01

    This paper presents several new techniques for volumetric cloud rendering using efficient algorithms and data structures based on ray-tracing methods for cumulus generation, achieving an optimum balance between realism and performance. These techniques target applications such as flight simulations, computer games, and educational software, even with conventional graphics hardware. The contours of clouds are defined by implicit mathematical expressions or triangulated structures inside which ...

  18. Unconscious neural processing differs with method used to render stimuli invisible

    Directory of Open Access Journals (Sweden)

    Sergey Victor Fogelson

    2014-06-01

    Full Text Available Visual stimuli can be kept from awareness using various methods. The extent of processing that a given stimulus receives in the absence of awareness is typically used to make claims about the role of consciousness more generally. The neural processing elicited by a stimulus, however, may also depend on the method used to keep it from awareness, and not only on whether the stimulus reaches awareness. Here we report that the method used to render an image invisible has a dramatic effect on how category information about the unseen stimulus is encoded across the human brain. We collected fMRI data while subjects viewed images of faces and tools, that were rendered invisible using either continuous flash suppression (CFS or chromatic flicker fusion (CFF. In a third condition, we presented the same images under normal fully visible viewing conditions. We found that category information about visible images could be extracted from patterns of fMRI responses throughout areas of neocortex known to be involved in face or tool processing. However, category information about stimuli kept from awareness using CFS could be recovered exclusively within occipital cortex, whereas information about stimuli kept from awareness using CFF was also decodable within temporal and frontal regions. We conclude that unconsciously presented objects are processed differently depending on how they are rendered subjectively invisible. Caution should therefore be used in making generalizations on the basis of any one method about the neural basis of consciousness or the extent of information processing without consciousness.

  19. Unconscious neural processing differs with method used to render stimuli invisible.

    Science.gov (United States)

    Fogelson, Sergey V; Kohler, Peter J; Miller, Kevin J; Granger, Richard; Tse, Peter U

    2014-01-01

    Visual stimuli can be kept from awareness using various methods. The extent of processing that a given stimulus receives in the absence of awareness is typically used to make claims about the role of consciousness more generally. The neural processing elicited by a stimulus, however, may also depend on the method used to keep it from awareness, and not only on whether the stimulus reaches awareness. Here we report that the method used to render an image invisible has a dramatic effect on how category information about the unseen stimulus is encoded across the human brain. We collected fMRI data while subjects viewed images of faces and tools, that were rendered invisible using either continuous flash suppression (CFS) or chromatic flicker fusion (CFF). In a third condition, we presented the same images under normal fully visible viewing conditions. We found that category information about visible images could be extracted from patterns of fMRI responses throughout areas of neocortex known to be involved in face or tool processing. However, category information about stimuli kept from awareness using CFS could be recovered exclusively within occipital cortex, whereas information about stimuli kept from awareness using CFF was also decodable within temporal and frontal regions. We conclude that unconsciously presented objects are processed differently depending on how they are rendered subjectively invisible. Caution should therefore be used in making generalizations on the basis of any one method about the neural basis of consciousness or the extent of information processing without consciousness.

  20. CT portography by multidetector helical CT. Comparison of three rendering models

    International Nuclear Information System (INIS)

    Nakayama, Yoshiharu; Imuta, Masanori; Funama, Yoshinori; Kadota, Masataka; Utsunomiya, Daisuke; Shiraishi, Shinya; Hayashida, Yoshiko; Yamashita, Yasuyuki

    2002-01-01

    The purpose of this study was to assess the value of multidetector CT portography in visualizing varices and portosystemic collaterals in comparison with conventional portography, and to compare the visualizations obtained by three rendering models (volume rendering, VR; minimum intensity projection, MIP; and shaded surface display, SSD). A total of 46 patients with portal hypertension were examined by CT and conventional portography for evaluation of portosystemic collaterals. CT portography was performed by multidetector CT (MD-CT) scanner with a slice thickness of 2.5 mm and table feed of 7.5 mm. Three types of CT portographic models were generated and compared with transarterial portography. Among 46 patients, 48 collaterals were identified on CT transverse images, while 38 collaterals were detected on transarterial portography. Forty-four of 48 collaterals identified on CT transverse images were visualized with the MIP model, while 34 and 29 collaterals were visualized by the VR and SSD methods, respectively. The average CT value for the portal vein and varices was 198 HU with data acquisition of 50 sec after contrast material injection. CT portography by multidetector CT provides excellent images in the visualization of portosystemic collaterals. The images of collaterals produced by MD-CT are superior to those of transarterial portography. Among the three rendering techniques, MIP provides the best visualization of portosystemic collaterals. (author)

  1. One-Dimensional Haptic Rendering Using Audio Speaker with Displacement Determined by Inductance

    Directory of Open Access Journals (Sweden)

    Avin Khera

    2016-03-01

    Full Text Available We report overall design considerations and preliminary results for a new haptic rendering device based on an audio loudspeaker. Our application models tissue properties during microsurgery. For example, the device could respond to the tip of a tool by simulating a particular tissue, displaying a desired compressibility and viscosity, giving way as the tissue is disrupted, or exhibiting independent motion, such as that caused by pulsations in blood pressure. Although limited to one degree of freedom and with a relatively small range of displacement compared to other available haptic rendering devices, our design exhibits high bandwidth, low friction, low hysteresis, and low mass. These features are consistent with modeling interactions with delicate tissues during microsurgery. In addition, our haptic rendering device is designed to be simple and inexpensive to manufacture, in part through an innovative method of measuring displacement by existing variations in the speaker’s inductance as the voice coil moves over the permanent magnet. Low latency and jitter are achieved by running the real-time simulation models on a dedicated microprocessor, while maintaining bidirectional communication with a standard laptop computer for user controls and data logging.

  2. Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study.

    Science.gov (United States)

    Ebert, Lars C; Schweitzer, Wolf; Gascho, Dominic; Ruder, Thomas D; Flach, Patricia M; Thali, Michael J; Ampanozi, Garyfalia

    2017-02-01

    The 3D volume-rendering technique (VRT) is commonly used in forensic radiology. Its main function is to explain medical findings to state attorneys, judges, or police representatives. New visualization algorithms permit the generation of almost photorealistic volume renderings of CT datasets. The objective of this study is to present and compare a variety of radiologic findings to illustrate the differences between and the advantages and limitations of the current VRT and the physically based cinematic rendering technique (CRT). Seventy volunteers were shown VRT and CRT reconstructions of 10 different cases. They were asked to mark the findings on the images and rate them in terms of realism and understandability. A total of 48 of the 70 questionnaires were returned and included in the analysis. On the basis of most of the findings presented, CRT appears to be equal or superior to VRT with respect to the realism and understandability of the visualized findings. Overall, in terms of realism, the difference between the techniques was statistically significant (p 0.05). CRT, which is similar to conventional VRT, is not primarily intended for diagnostic radiologic image analysis, and therefore it should be used primarily as a tool to deliver visual information in the form of radiologic image reports. Using CRT for forensic visualization might have advantages over using VRT if conveying a high degree of visual realism is of importance. Most of the shortcomings of CRT have to do with the software being an early prototype.

  3. CT portography by multidetector helical CT. Comparison of three rendering models

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Yoshiharu; Imuta, Masanori; Funama, Yoshinori; Kadota, Masataka; Utsunomiya, Daisuke; Shiraishi, Shinya; Hayashida, Yoshiko; Yamashita, Yasuyuki [Kumamoto Univ. (Japan). School of Medicine

    2002-12-01

    The purpose of this study was to assess the value of multidetector CT portography in visualizing varices and portosystemic collaterals in comparison with conventional portography, and to compare the visualizations obtained by three rendering models (volume rendering, VR; minimum intensity projection, MIP; and shaded surface display, SSD). A total of 46 patients with portal hypertension were examined by CT and conventional portography for evaluation of portosystemic collaterals. CT portography was performed by multidetector CT (MD-CT) scanner with a slice thickness of 2.5 mm and table feed of 7.5 mm. Three types of CT portographic models were generated and compared with transarterial portography. Among 46 patients, 48 collaterals were identified on CT transverse images, while 38 collaterals were detected on transarterial portography. Forty-four of 48 collaterals identified on CT transverse images were visualized with the MIP model, while 34 and 29 collaterals were visualized by the VR and SSD methods, respectively. The average CT value for the portal vein and varices was 198 HU with data acquisition of 50 sec after contrast material injection. CT portography by multidetector CT provides excellent images in the visualization of portosystemic collaterals. The images of collaterals produced by MD-CT are superior to those of transarterial portography. Among the three rendering techniques, MIP provides the best visualization of portosystemic collaterals. (author)

  4. Simulation and training of lumbar punctures using haptic volume rendering and a 6DOF haptic device

    Science.gov (United States)

    Färber, Matthias; Heller, Julika; Handels, Heinz

    2007-03-01

    The lumbar puncture is performed by inserting a needle into the spinal chord of the patient to inject medicaments or to extract liquor. The training of this procedure is usually done on the patient guided by experienced supervisors. A virtual reality lumbar puncture simulator has been developed in order to minimize the training costs and the patient's risk. We use a haptic device with six degrees of freedom (6DOF) to feedback forces that resist needle insertion and rotation. An improved haptic volume rendering approach is used to calculate the forces. This approach makes use of label data of relevant structures like skin, bone, muscles or fat and original CT data that contributes information about image structures that can not be segmented. A real-time 3D visualization with optional stereo view shows the punctured region. 2D visualizations of orthogonal slices enable a detailed impression of the anatomical context. The input data consisting of CT and label data and surface models of relevant structures is defined in an XML file together with haptic rendering and visualization parameters. In a first evaluation the visible human male data has been used to generate a virtual training body. Several users with different medical experience tested the lumbar puncture trainer. The simulator gives a good haptic and visual impression of the needle insertion and the haptic volume rendering technique enables the feeling of unsegmented structures. Especially, the restriction of transversal needle movement together with rotation constraints enabled by the 6DOF device facilitate a realistic puncture simulation.

  5. A Single Swede Midge (Diptera: Cecidomyiidae) Larva Can Render Cauliflower Unmarketable.

    Science.gov (United States)

    Stratton, Chase A; Hodgdon, Elisabeth A; Zuckerman, Samuel G; Shelton, Anthony M; Chen, Yolanda H

    2018-05-01

    Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), is an invasive pest causing significant damage on Brassica crops in the Northeastern United States and Eastern Canada. Heading brassicas, like cauliflower, appear to be particularly susceptible. Swede midge is difficult to control because larvae feed concealed inside meristematic tissues of the plant. In order to develop damage and marketability thresholds necessary for integrated pest management, it is important to determine how many larvae render plants unmarketable and whether the timing of infestation affects the severity of damage. We manipulated larval density (0, 1, 3, 5, 10, or 20) per plant and the timing of infestation (30, 55, and 80 d after seeding) on cauliflower in the lab and field to answer the following questions: 1) What is the swede midge damage threshold? 2) How many swede midge larvae can render cauliflower crowns unmarketable? and 3) Does the age of cauliflower at infestation influence the severity of damage and marketability? We found that even a single larva can cause mild twisting and scarring in the crown rendering cauliflower unmarketable 52% of the time, with more larvae causing more severe damage and additional losses, regardless of cauliflower age at infestation.

  6. Adaptive B-spline volume representation of measured BRDF data for photorealistic rendering

    Directory of Open Access Journals (Sweden)

    Hyungjun Park

    2015-01-01

    Full Text Available Measured bidirectional reflectance distribution function (BRDF data have been used to represent complex interaction between lights and surface materials for photorealistic rendering. However, their massive size makes it hard to adopt them in practical rendering applications. In this paper, we propose an adaptive method for B-spline volume representation of measured BRDF data. It basically performs approximate B-spline volume lofting, which decomposes the problem into three sub-problems of multiple B-spline curve fitting along u-, v-, and w-parametric directions. Especially, it makes the efficient use of knots in the multiple B-spline curve fitting and thereby accomplishes adaptive knot placement along each parametric direction of a resulting B-spline volume. The proposed method is quite useful to realize efficient data reduction while smoothing out the noises and keeping the overall features of BRDF data well. By applying the B-spline volume models of real materials for rendering, we show that the B-spline volume models are effective in preserving the features of material appearance and are suitable for representing BRDF data.

  7. [Study on the arc spectral information for welding quality diagnosis].

    Science.gov (United States)

    Li, Zhi-Yong; Gu, Xiao-Yan; Li, Huan; Yang, Li-Jun

    2009-03-01

    Through collecting the spectral signals of TIG and MIG welding arc with spectrometer, the arc light radiations were analyzed based on the basic theory of plasma physics. The radiation of welding arc distributes over a broad range of frequency, from infrared to ultraviolet. The arc spectrum is composed of line spectra and continuous spectra. Due to the variation of metal density in the welding arc, there is great difference between the welding arc spectra of TIG and MIG in both their intensity and distribution. The MIG welding arc provides more line spectra of metal and the intensity of radiation is greater than TIG. The arc spectrum of TIG welding is stable during the welding process, disturbance factors that cause the spectral variations can be reflected by the spectral line related to the corresponding element entering the welding arc. The arc spectrum of MIG welding will fluctuate severely due to droplet transfer, which produces "noise" in the line spectrum aggregation zone. So for MIG welding, the spectral zone lacking spectral line is suitable for welding quality diagnosis. According to the characteristic of TIG and MIG, special spectral zones were selected for welding quality diagnosis. For TIG welding, the selected zone is in ultraviolet zone (230-300 nm). For MIG welding, the selected zone is in visible zone (570-590 nm). With the basic theory provided for welding quality diagnosis, the integral intensity of spectral signal in the selected zone of welding process with disturbing factor was studied to prove the theory. The results show that the welding quality and disturbance factors can be diagnosed with good signal to noise ratio in the selected spectral zone compared with signal in other spectral zone. The spectral signal can be used for real-time diagnosis of the welding quality.

  8. Rectangular spectral collocation

    KAUST Repository

    Driscoll, Tobin A.

    2015-02-06

    Boundary conditions in spectral collocation methods are typically imposed by removing some rows of the discretized differential operator and replacing them with others that enforce the required conditions at the boundary. A new approach based upon resampling differentiated polynomials into a lower-degree subspace makes differentiation matrices, and operators built from them, rectangular without any row deletions. Then, boundary and interface conditions can be adjoined to yield a square system. The resulting method is both flexible and robust, and avoids ambiguities that arise when applying the classical row deletion method outside of two-point scalar boundary-value problems. The new method is the basis for ordinary differential equation solutions in Chebfun software, and is demonstrated for a variety of boundary-value, eigenvalue and time-dependent problems.

  9. Spectral evolution of galaxies

    International Nuclear Information System (INIS)

    Rocca-Volmerange, B.

    1989-01-01

    A recent striking event in Observational Cosmology is the discovery of a large population of galaxies at extreme cosmological distances (extended from spectral redshifts ≅ 1 to ≥ 3) corresponding to a lookback time of 80% of the Universe's age. However when galaxies are observed at such remote epochs, their appearances are affected by at least two simultaneous effects which are respectively a cosmological effect and the intrinsic evolution of their stellar populations which appear younger than in our nearby galaxies. The fundamental problem is first to disentangle the respective contributions of these two effects to apparent magnitudes and colors of distant galaxies. Other effects which are likely to modify the appearance of galaxies are amplification by gravitational lensing and interaction with environment will also be considered. (author)

  10. Spectral Line Shapes. Proceedings

    International Nuclear Information System (INIS)

    Zoppi, M.; Ulivi, L.

    1997-01-01

    These proceedings represent papers presented at the 13th International Conference on Spectral Line Shapes which was held in Firenze,Italy from June 16-21, 1996. The topics covered a wide range of subjects emphasizing the physical processes associated with the formation of line profiles: high and low density plasma; atoms and molecules in strong laser fields, Dopple-free and ultra-fine spectroscopy; the line shapes generated by the interaction of neutrals, atoms and molecules, where the relavant quantities are single particle properties, and the interaction-induced spectroscopy. There were 131 papers presented at the conference, out of these, 6 have been abstracted for the Energy Science and Technology database

  11. Museum lighting for golden artifacts, with low correlated color temperature, high color uniformity and high color rendering index, using diffusing color mixing of red, cyan, and white-light-emitting diodes

    DEFF Research Database (Denmark)

    Thorseth, Anders; Corell, Dennis Dan; Poulsen, Peter Behrensdorff

    2012-01-01

    at the Royal Danish Collection at Rosenborg Castle. Color mixing of red, cyan, and white LEDs was employed to achieve the spectral power distribution needed for the required CCT and a CRI above 90. Color uniformity is achieved by the use of a highly diffusing reflector. The system has shown energy saving above......Museum lighting presents challenges mainly due to the demand for precise color rendering and the damaging effects of radiation. Golden objects must normally be illuminated by the non-standard CCT of 2200 K. An LED system that conforms to these requirements has been developed and implemented...

  12. Fuel element

    International Nuclear Information System (INIS)

    Armijo, J.S.

    1976-01-01

    A fuel element for nuclear reactors is proposed which has a higher corrosion resisting quality in reactor operations. The zirconium alloy coating around the fuel element (uranium or plutonium compound) has on its inside a protection layer of metal which is metallurgically bound to the substance of the coating. As materials are namned: Alluminium, copper, niobium, stainless steel, and iron. This protective metallic layer has another inner layer, also metallurgically bound to its surface, which consists usually of a zirconium alloy. (UWI) [de

  13. ATR neutron spectral characterization

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.W.; Anderl, R.A.

    1995-11-01

    The Advanced Test Reactor (ATR) at INEL provides intense neutron fields for irradiation-effects testing of reactor material samples, for production of radionuclides used in industrial and medical applications, and for scientific research. Characterization of the neutron environments in the irradiation locations of the ATR has been done by means of neutronics calculations and by means of neutron dosimetry based on the use of neutron activation monitors that are placed in the various irradiation locations. The primary purpose of this report is to present the results of an extensive characterization of several ATR irradiation locations based on neutron dosimetry measurements and on least-squares-adjustment analyses that utilize both neutron dosimetry measurements and neutronics calculations. This report builds upon the previous publications, especially the reference 4 paper. Section 2 provides a brief description of the ATR and it tabulates neutron spectral information for typical irradiation locations, as derived from the more historical neutron dosimetry measurements. Relevant details that pertain to the multigroup neutron spectral characterization are covered in section 3. This discussion includes a presentation on the dosimeter irradiation and analyses and a development of the least-squares adjustment methodology, along with a summary of the results of these analyses. Spectrum-averaged cross sections for neutron monitoring and for displacement-damage prediction in Fe, Cr, and Ni are given in section 4. In addition, section4 includes estimates of damage generation rates for these materials in selected ATR irradiation locations. In section 5, the authors present a brief discussion of the most significant conclusions of this work and comment on its relevance to the present ATR core configuration. Finally, detailed numerical and graphical results for the spectrum-characterization analyses in each irradiation location are provided in the Appendix.

  14. [Research on developping the spectral dataset for Dunhuang typical colors based on color constancy].

    Science.gov (United States)

    Liu, Qiang; Wan, Xiao-Xia; Liu, Zhen; Li, Chan; Liang, Jin-Xing

    2013-11-01

    The present paper aims at developping a method to reasonably set up the typical spectral color dataset for different kinds of Chinese cultural heritage in color rendering process. The world famous wall paintings dating from more than 1700 years ago in Dunhuang Mogao Grottoes was taken as typical case in this research. In order to maintain the color constancy during the color rendering workflow of Dunhuang culture relics, a chromatic adaptation based method for developping the spectral dataset of typical colors for those wall paintings was proposed from the view point of human vision perception ability. Under the help and guidance of researchers in the art-research institution and protection-research institution of Dunhuang Academy and according to the existing research achievement of Dunhuang Research in the past years, 48 typical known Dunhuang pigments were chosen and 240 representative color samples were made with reflective spectral ranging from 360 to 750 nm was acquired by a spectrometer. In order to find the typical colors of the above mentioned color samples, the original dataset was devided into several subgroups by clustering analysis. The grouping number, together with the most typical samples for each subgroup which made up the firstly built typical color dataset, was determined by wilcoxon signed rank test according to the color inconstancy index comprehensively calculated under 6 typical illuminating conditions. Considering the completeness of gamut of Dunhuang wall paintings, 8 complementary colors was determined and finally the typical spectral color dataset was built up which contains 100 representative spectral colors. The analytical calculating results show that the median color inconstancy index of the built dataset in 99% confidence level by wilcoxon signed rank test was 3.28 and the 100 colors are distributing in the whole gamut uniformly, which ensures that this dataset can provide reasonable reference for choosing the color with highest

  15. The lime renderings from plaza de la Corredera, Córdoba

    Directory of Open Access Journals (Sweden)

    González, T.

    2002-09-01

    Full Text Available The causes of the pathologies found on the lime renderings from Plaza de la Corredera façades are analysed in this study. For this purpose, the mineralogical and chemical analyses of the building materials -brickwork and rendering mortar- has been carried out, as well as their physical, hydric and mechanical properties have been determined. The obtained results from both unaltered and altered materials, and the analysis of the rendering's raw materials, have allowed us to establish that rendering deterioration is connected to the presence of saline compounds (gypsum, halite, which existing in the brickwork substratum, have been removed due to the water saturation of such brickwork. The main cause responsible of the alteration forms - efflorescence, crusts, grain-disintegration, bulging, flaking found on the renderings, has been the salts precipitation (halite, hexahydrite, epsomite in their way towards the external surface.

    En este estudio se analizan las causas de las patologías de los revocos de cal de las fachadas de la Plaza de la Corredera. Para ello se ha realizado el análisis mineralógico y químico de los materiales de construcción - fábrica de ladrillo y mortero de revestimiento- y se han determinado sus propiedades físicas, hídricas y mecánicas. Mediante la comparación de los resultados obtenidos en los materiales inalterados y en los alterados, así como una vez analizadas las materias primas utilizadas en la realización del revoco, se ha podido establecer que la alteración de este último está relacionada con la existencia de compuestos salinos (yeso, halita que, presentes en el substrato de fábrica de ladrillo, se han exudado por saturación de agua de la misma. La precipitación de las sales (halita, hexahidrita, epsomita en su migración hacia el exterior ha sido la principal responsable de las formas de alteración -eflorescencias, costras, arenización, abombamientos, descamaciones- que aparecen sobre los

  16. Visualization of normal and abnormal inner ear with volume rendering technique using multislice spiral CT

    International Nuclear Information System (INIS)

    Ma Hui; Han Ping; Liang Bo; Lei Ziqiao; Liu Fang; Tian Zhiliang

    2006-01-01

    Objective: To evaluate the ability of the volume rendering technique to display the normal and abnormal inner ear structures. Methods: Forty normal earand 61 abnormal inner ears (40 congenital inner ear malformations, 7 labyrinthitis ossificans, and 14 inner ear erosion caused by cholesteatomas) were examined with a MSCT scanner. Axial imaging were performed using the following parameters: 120 kV, 100 mAs, 0.75 mm slice thickness, a pitch factor of 1. The axial images of interested ears were reconstructed with 0.1 mm reconstruction increment and a FOV of 50 mm. The 3D reconstructions were done with volume rendering technique on the workstation. Results: In the subjects without ear disorders a high quality 3D visualization of the inner ear could be achieved. In the patients with inner ear' disorders all inner ear malformations could be clearly displayed on 3D images as follows: (1) Michel deformity (one ear): There was complete absence of all cochlear and vestibular structures. (2) common cavity deformity (3 ears): The cochlea and vestibule were represented by a cystic cavity and couldn't be differentiated from each other. (3)incomplete partition type I (3 ears): The cochlea lacked the entire modiolus and cribriform area, resulting in a cystic appearance. (4) incomplete partition type II (Mondini deformity) (5 ears): The cochlea consisted of 1.5 turns, in which the middle and apical turns coalesced to form a cystic apex. (5) vestibular and semicircular canal malformations (14 ears): Cochlea was normal, vestibule dilated, semicircular canals were absent, hypoplastic or enlarged. (6) dilated vestibular aqueduct (14 ears): The vestibular aqueduct was bell-mouthed. In 7 patients with labyrinthifis ossificans, 3D images failed to clearly show the completeinner ears in 4 ears because of too high ossifications in the membranous labyrinth. In the other 3 ears volume rendering could display the thin cochlea basal turn and the intermittent semicircular canals. In the patients

  17. Spectral Theory of Chemical Bonding

    National Research Council Canada - National Science Library

    Langhoff, P. W; Boatz, J. A; Hinde, R. J; Sheehy, J. A

    2004-01-01

    .... Wave function antisymmetry in the aggregate atomic spectral-product basis is enforced by unitary transformation performed subsequent to formation of the Hamiltonian matrix, greatly simplifying its construction...

  18. [Review of digital ground object spectral library].

    Science.gov (United States)

    Zhou, Xiao-Hu; Zhou, Ding-Wu

    2009-06-01

    A higher spectral resolution is the main direction of developing remote sensing technology, and it is quite important to set up the digital ground object reflectance spectral database library, one of fundamental research fields in remote sensing application. Remote sensing application has been increasingly relying on ground object spectral characteristics, and quantitative analysis has been developed to a new stage. The present article summarized and systematically introduced the research status quo and development trend of digital ground object reflectance spectral libraries at home and in the world in recent years. Introducing the spectral libraries has been established, including desertification spectral database library, plants spectral database library, geological spectral database library, soil spectral database library, minerals spectral database library, cloud spectral database library, snow spectral database library, the atmosphere spectral database library, rocks spectral database library, water spectral database library, meteorites spectral database library, moon rock spectral database library, and man-made materials spectral database library, mixture spectral database library, volatile compounds spectral database library, and liquids spectral database library. In the process of establishing spectral database libraries, there have been some problems, such as the lack of uniform national spectral database standard and uniform standards for the ground object features as well as the comparability between different databases. In addition, data sharing mechanism can not be carried out, etc. This article also put forward some suggestions on those problems.

  19. PELTIER ELEMENTS

    CERN Document Server

    Tani, Laurits

    2015-01-01

    To control Peltier elements, temperature controller was used. I used TEC-1091 that was manufactured my Meerstetter Engineering. To gain control with the temperature controller, software had to be intalled on a controlling PC. There were different modes to control the Peltier: Tempererature controller to control temperature, Static current/voltage to control voltage and current and LIVE ON/OFF to auto-tune the controller respectively to the system. Also, since near the collision pipe there is much radiation, radiation-proof Peltier elements have to be used. To gain the best results, I had to find the most efficient Peltier elements and try to get their cold side to -40 degrees Celsius.

  20. SPECTRAL ANALYSIS OF EXCHANGE RATES

    Directory of Open Access Journals (Sweden)

    ALEŠA LOTRIČ DOLINAR

    2013-06-01

    Full Text Available Using spectral analysis is very common in technical areas but rather unusual in economics and finance, where ARIMA and GARCH modeling are much more in use. To show that spectral analysis can be useful in determining hidden periodic components for high-frequency finance data as well, we use the example of foreign exchange rates

  1. VIDEO ANIMASI 3D PENGENALAN RUMAH ADAT DAN ALAT MUSIK KEPRI DENGAN MENGUNAKAN TEKNIK RENDER CEL-SHADING

    Directory of Open Access Journals (Sweden)

    Jianfranco Irfian Asnawi

    2016-11-01

    Full Text Available Animasi ini berjudul "video animasi 3D rumah adat dan alat musik Kepulauan Riau dengan menggunakan teknik render cel-shading" merupakan video yang bertujuan memperkenalkan alat-alat musik yang berasal dari kepulauan riau, Animasi ini akan diterapkan dengan menggunakan teknik render cel-shading. Cel-shading adalah teknik render yang menampilkan grafik 3D yang menyerupai gambar tangan, seperti gambar komik dan kartun. Teknik ini juga sudah di terapkan dalam game 3D yang ternyata menarik banyak perhatian peminat. Teknik ini akan di terapkan kedalam animasi 3D "video animasi rumah adat dan alat musik kepulauan riau dengan menggunakan teknik render cel-shading" Animasi di rancang menggunakan skenario dan storyboard kemudian di implementasikan dalam software 3D MAYA AUTODESK dengan menggunakan teknik render cel-shading. Setelah diterapkan maka di dapatkan definisi keberhasilan dari teknik render cel shading di bandingkan dengan teknik render global illumination seperti dari kecepatan dalam merender dan tingkat kecerahan warna pada video. Kata kunci: animasi, game 3D, cel-shading.

  2. ULTRAVIOLET RAMAN SPECTRAL SIGNATURE ACQUISITION: UV RAMAN SPECTRAL FINGERPRINTS.

    Energy Technology Data Exchange (ETDEWEB)

    SEDLACEK,III, A.J.FINFROCK,C.

    2002-09-01

    As a member of the science-support part of the ITT-lead LISA development program, BNL is tasked with the acquisition of UV Raman spectral fingerprints and associated scattering cross-sections for those chemicals-of-interest to the program's sponsor. In support of this role, the present report contains the first installment of UV Raman spectral fingerprint data on the initial subset of chemicals. Because of the unique nature associated with the acquisition of spectral fingerprints for use in spectral pattern matching algorithms (i.e., CLS, PLS, ANN) great care has been undertaken to maximize the signal-to-noise and to minimize unnecessary spectral subtractions, in an effort to provide the highest quality spectral fingerprints. This report is divided into 4 sections. The first is an Experimental section that outlines how the Raman spectra are performed. This is then followed by a section on Sample Handling. Following this, the spectral fingerprints are presented in the Results section where the data reduction process is outlined. Finally, a Photographs section is included.

  3. Advantages and disadvantages of 3D ultrasound of thyroid nodules including thin slice volume rendering

    Directory of Open Access Journals (Sweden)

    Slapa Rafal

    2011-01-01

    Full Text Available Abstract Background The purpose of this study was to assess the advantages and disadvantages of 3D gray-scale and power Doppler ultrasound, including thin slice volume rendering (TSVR, applied for evaluation of thyroid nodules. Methods The retrospective evaluation by two observers of volumes of 71 thyroid nodules (55 benign, 16 cancers was performed using a new TSVR technique. Dedicated 4D ultrasound scanner with an automatic 6-12 MHz 4D probe was used. Statistical analysis was performed with Stata v. 8.2. Results Multiple logistic regression analysis demonstrated that independent risk factors of thyroid cancers identified by 3D ultrasound include: (a ill-defined borders of the nodule on MPR presentation, (b a lobulated shape of the nodule in the c-plane and (c a density of central vessels in the nodule within the minimal or maximal ranges. Combination of features provided sensitivity 100% and specificity 60-69% for thyroid cancer. Calcification/microcalcification-like echogenic foci on 3D ultrasound proved not to be a risk factor of thyroid cancer. Storage of the 3D data of the whole nodules enabled subsequent evaluation of new parameters and with new rendering algorithms. Conclusions Our results indicate that 3D ultrasound is a practical and reproducible method for the evaluation of thyroid nodules. 3D ultrasound stores volumes comprising the whole lesion or organ. Future detailed evaluations of the data are possible, looking for features that were not fully appreciated at the time of collection or applying new algorithms for volume rendering in order to gain important information. Three-dimensional ultrasound data could be included in thyroid cancer databases. Further multicenter large scale studies are warranted.

  4. A Case Study of a Hybrid Parallel 3D Surface Rendering Graphics Architecture

    DEFF Research Database (Denmark)

    Holten-Lund, Hans Erik; Madsen, Jan; Pedersen, Steen

    1997-01-01

    This paper presents a case study in the design strategy used inbuilding a graphics computer, for drawing very complex 3Dgeometric surfaces. The goal is to build a PC based computer systemcapable of handling surfaces built from about 2 million triangles, andto be able to render a perspective view...... of these on a computer displayat interactive frame rates, i.e. processing around 50 milliontriangles per second. The paper presents a hardware/softwarearchitecture called HPGA (Hybrid Parallel Graphics Architecture) whichis likely to be able to carry out this task. The case study focuses ontechniques to increase...

  5. Three-dimensional rendering of otolith growth using phase contrast synchrotron tomography.

    Science.gov (United States)

    Mapp, J J I; Fisher, M H; Atwood, R C; Bell, G D; Greco, M K; Songer, S; Hunter, E

    2016-05-01

    A three-dimensional computer reconstruction of a plaice Pleuronectes platessa otolith is presented from data acquired by the Diamond Light synchrotron, beamline I12, X-ray source, a high energy (53-150 keV) source particularly well suited to the study of dense objects. The data allowed non-destructive rendering of otolith structure, and for the first time allows otolith annuli (internal ring structures) to be analysed in X-ray tomographic images. © 2016 The Fisheries Society of the British Isles.

  6. [Rendering surgical care to wounded with neck wounds in an armed conflict].

    Science.gov (United States)

    Samokhvalov, I M; Zavrazhnov, A A; Fakhrutdinov, A M; Sychev, M I

    2001-10-01

    The results of rendering of the medical care (the first aid, qualified and specialized) obtained in 172 servicemen with neck injuries who stayed in Republic of Chechnya during the period from 09.08.1999 to 28.07.2000 were analyzed. Basing on the results of analysis and experience of casualties' treatment the authors discuss the problems of sequence and volume of surgical care in this group of casualties with reference to available medical evacuation system, surgical tactics at the stage of specialized care. They also consider the peculiarities of operative treatment of the casualties with neck injuries.

  7. Experimental and rendering-based investigation of laser radar cross sections of small unmanned aerial vehicles

    Science.gov (United States)

    Laurenzis, Martin; Bacher, Emmanuel; Christnacher, Frank

    2017-12-01

    Laser imaging systems are prominent candidates for detection and tracking of small unmanned aerial vehicles (UAVs) in current and future security scenarios. Laser reflection characteristics for laser imaging (e.g., laser gated viewing) of small UAVs are investigated to determine their laser radar cross section (LRCS) by analyzing the intensity distribution of laser reflection in high resolution images. For the first time, LRCSs are determined in a combined experimental and computational approaches by high resolution laser gated viewing and three-dimensional rendering. An optimized simple surface model is calculated taking into account diffuse and specular reflectance properties based on the Oren-Nayar and the Cook-Torrance reflectance models, respectively.

  8. Peeling tests for assessing the cohesion and consolidation characteristics of mortar and render surfaces

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš; Lesák, Jaroslav; Niedoba, Krzysztof; Valach, Jaroslav

    2015-01-01

    Roč. 48, č. 6 (2015), s. 1947-1963 ISSN 1359-5997 R&D Projects: GA ČR(CZ) GBP105/12/G059; GA MŠk(CZ) ED1.1.00/02.0060 Institutional support: RVO:68378297 Keywords : peeling test * rendered surface * surface consolidation * cohesion * non-destructive testing Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.453, year: 2015 http://link.springer.com/article/10.1617/s11527-014-0285-8

  9. Semiconductive 3-D haloplumbate framework hybrids with high color rendering index white-light emission.

    Science.gov (United States)

    Wang, Guan-E; Xu, Gang; Wang, Ming-Sheng; Cai, Li-Zhen; Li, Wen-Hua; Guo, Guo-Cong

    2015-12-01

    Single-component white light materials may create great opportunities for novel conventional lighting applications and display systems; however, their reported color rendering index (CRI) values, one of the key parameters for lighting, are less than 90, which does not satisfy the demand of color-critical upmarket applications, such as photography, cinematography, and art galleries. In this work, two semiconductive chloroplumbate (chloride anion of lead(ii)) hybrids, obtained using a new inorganic-organic hybrid strategy, show unprecedented 3-D inorganic framework structures and white-light-emitting properties with high CRI values around 90, one of which shows the highest value to date.

  10. Use of multidetector row CT with volume renderings in right lobe living liver transplantation

    International Nuclear Information System (INIS)

    Ishifuro, Minoru; Akiyama, Yuji; Kushima, Toshio; Horiguchi, Jun; Nakashige, Aya; Tamura, Akihisa; Marukawa, Kazushi; Fukuda, Hiroshi; Ono, Chiaki; Ito, Katsuhide

    2002-01-01

    Multidetector row CT is a feasible diagnostic tool in pre- and postoperative liver partial transplantation. We can assess vascular anatomy and liver parenchyma as well as volumetry, which provide useful information for both donor selection and surgical planning. Disorders of the vascular and biliary systems are carefully observed in recipients. In addition, we evaluate liver regeneration of both the donor and the recipient by serial volumetry. We present how multidetector row CT with state-of-the-art three-dimensional volume renderings may be used in right lobe liver transplantation. (orig.)

  11. Uniform illumination rendering using an array of LEDs: a signal processing perspective

    OpenAIRE

    Yang, Hongming; Bergmans, J.W.M.; Schenk, T.C.W.; Linnartz, J.P.M.G.; Rietman, R.

    2009-01-01

    An array of a large number of LEDs will be widely used in future indoor illumination systems. In this paper, we investigate the problem of rendering uniform illumination by a regular LED array on the ceiling of a room. We first present two general results on the scaling property of the basic illumination pattern, i.e., the light pattern of a single LED, and the setting of LED illumination levels, respectively. Thereafter, we propose to use the relative mean squared error as the cost function ...

  12. Fuel element

    International Nuclear Information System (INIS)

    Kennedy, S.T.

    1982-01-01

    A nuclear reactor fuel element wherein a stack of nuclear fuel is prevented from displacement within its sheath by a retainer comprising a tube member which is radially expanded into frictional contact with the sheath by means of a captive ball within a tapered bore. (author)

  13. Transactinide elements

    International Nuclear Information System (INIS)

    Hemingway, J.D.

    1975-01-01

    The review is covered in sections, entitled: predicted nuclear properties - including closed shells, decay characteristics; predicted chemical properties - including electronic structure and calculated properties, X-radiation, extrapolated chemical properties, separation chemistry; methods of synthesis; the natural occurrence of superheavy elements. (U.K.)

  14. Elements in the history of the Periodic Table.

    Science.gov (United States)

    Rouvray, Dennis H

    2004-06-01

    Discovery of the Periodic Table was rendered possible only after four decisive prerequisites had been achieved. These were (i) the abandonment of the metaphysical and occult notions of elements that typified the alchemical era; (ii) the adoption of a modern and workable definition of an element; (iii) the development of analytical chemical techniques for the isolation of the elements and determination of their properties; and (iv) the devising of a means of associating each element with a characteristic natural number. The Periodic Table made its appearance on cue almost as soon as these preconditions had been fulfilled.

  15. Development of volume rendering module for real-time visualization system

    International Nuclear Information System (INIS)

    Otani, Takayuki; Muramatsu, Kazuhiro

    2000-03-01

    Volume rendering is a method to visualize the distribution of physical quantities in the three dimensional space from any viewpoint by tracing the ray direction on the ordinary two dimensional monitoring display. It enables to provide the interior information as well as the surfacial one by producing the translucent images. Therefore, it is regarded as a very useful means as well as an important one in the analysis of the computational results of the scientific calculations, although it has, unfortunately, disadvantage to need a large amount of computing time. This report describes algorithm and its performance of the volume rendering soft-ware which was developed as an important functional module in the real-time visualization system PATRAS. This module can directly visualize the computed results on BFC grid. Moreover, it has already realized the speed-up in some parts of the software by the use of a newly developed heuristic technique. This report includes the investigation on the speed-up of the software by parallel processing. (author)

  16. State of the Art in Transfer Functions for Direct Volume Rendering

    KAUST Repository

    Ljung, Patric; Krü ger, Jens; Groller, Eduard; Hadwiger, Markus; Hansen, Charles D.; Ynnerman, Anders

    2016-01-01

    A central topic in scientific visualization is the transfer function (TF) for volume rendering. The TF serves a fundamental role in translating scalar and multivariate data into color and opacity to express and reveal the relevant features present in the data studied. Beyond this core functionality, TFs also serve as a tool for encoding and utilizing domain knowledge and as an expression for visual design of material appearances. TFs also enable interactive volumetric exploration of complex data. The purpose of this state-of-the-art report (STAR) is to provide an overview of research into the various aspects of TFs, which lead to interpretation of the underlying data through the use of meaningful visual representations. The STAR classifies TF research into the following aspects: dimensionality, derived attributes, aggregated attributes, rendering aspects, automation, and user interfaces. The STAR concludes with some interesting research challenges that form the basis of an agenda for the development of next generation TF tools and methodologies. © 2016 The Author(s) Computer Graphics Forum © 2016 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

  17. Evaluating Approaches to Rendering Braille Text on a High-Density Pin Display.

    Science.gov (United States)

    Morash, Valerie S; Russomanno, Alexander; Gillespie, R Brent; OModhrain, Sile

    2017-10-13

    Refreshable displays for tactile graphics are typically composed of pins that have smaller diameters and spacing than standard braille dots. We investigated configurations of high-density pins to form braille text on such displays using non-refreshable stimuli produced with a 3D printer. Normal dot braille (diameter 1.5 mm) was compared to high-density dot braille (diameter 0.75 mm) wherein each normal dot was rendered by high-density simulated pins alone or in a cluster of pins configured in a diamond, X, or square; and to "blobs" that could result from covering normal braille and high-density multi-pin configurations with a thin membrane. Twelve blind participants read MNREAD sentences displayed in these conditions. For high-density simulated pins, single pins were as quickly and easily read as normal braille, but diamond, X, and square multi-pin configurations were slower and/or harder to read than normal braille. We therefore conclude that as long as center-to-center dot spacing and dot placement is maintained, the dot diameter may be open to variability for rendering braille on a high density tactile display.

  18. Mesophilic and thermophilic anaerobic co-digestion of rendering plant and slaughterhouse wastes.

    Science.gov (United States)

    Bayr, Suvi; Rantanen, Marianne; Kaparaju, Prasad; Rintala, Jukka

    2012-01-01

    Co-digestion of rendering and slaughterhouse wastes was studied in laboratory scale semi-continuously fed continuously stirred tank reactors (CSTRs) at 35 and 55 °C. All in all, 10 different rendering plant and slaughterhouse waste fractions were characterised showing high contents of lipids and proteins, and methane potentials of 262-572 dm(3)CH(4)/kg volatile solids(VS)(added). In mesophilic CSTR methane yields of ca 720 dm(3) CH(4)/kg VS(fed) were obtained with organic loading rates (OLR) of 1.0 and 1.5 kg VS/m(3) d, and hydraulic retention time (HRT) of 50 d. For thermophilic process, the lowest studied OLR of 1.5 kg VS/m(3) d, turned to be unstable after operation of 1.5 HRT, due to accumulating ammonia, volatile fatty acids (VFAs) and probably also long chain fatty acids (LCFAs). In conclusion, mesophilic process was found to be more feasible for co-digestion than thermophilic process, methane yields being higher and process more stable in mesophilic conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Clinical application of three-dimensional spiral CT cerebral angiography with volume rendering

    International Nuclear Information System (INIS)

    Duan Shaoyin; Huang Xi'en; Kang Jianghe; Zhang Dantong; Lin Qingchi; Cai Guoxiang; Xu Meixin; Pang Ruilin

    2002-01-01

    Objective: To study the methodology and assess the clinical value of three-dimensional CT angiography (3D-CTA) with volume rendering (VR) in cerebral vessels. Methods: Sixty-two patients were examined by means of 3D-CTA with volume rendering. VR was used in the reconstruction of 3D images, and the demonstration of normal vessels and vascular lesions were particularly analyzed. At the same time, comparisons were made between the images of VR and SSD, MIP, and also between the diagnosis of VR-CTA and DSA or postoperative results. Results: In VR images, cerebral vessel routes and vessel cavities were showed clearly, while the relationship among vascular lesions, surrounding vessels, and neighboring structure was distinguished. 50 cases (80.6%) were found positive, 48 of which were correct and 2 were false-positive compared with DSA or postoperative results. The accurate rate of diagnosis was 96.0%. There was no obvious difference in showing the cerebral vessel among the images of VR, SSD and MIP (P > 0.25). Conclusion: Three-dimensional CT cerebral angiography with VR is a new noninvasive effective method. It can even partly replace the DSA. The 3D-images have the characteristics of showing the cerebral vascular cavity and overlapped vessels without cutting the skull

  20. INCREASING SAVING BEHAVIOR THROUGH AGE-PROGRESSED RENDERINGS OF THE FUTURE SELF

    Science.gov (United States)

    HERSHFIELD, HAL E.; GOLDSTEIN, DANIEL G.; SHARPE, WILLIAM F.; FOX, JESSE; YEYKELIS, LEO; CARSTENSEN, LAURA L.; BAILENSON, JEREMY N.

    2014-01-01

    Many people fail to save what they need to for retirement (Munnell, Webb, and Golub-Sass 2009). Research on excessive discounting of the future suggests that removing the lure of immediate rewards by pre-committing to decisions, or elaborating the value of future rewards can both make decisions more future-oriented. In this article, we explore a third and complementary route, one that deals not with present and future rewards, but with present and future selves. In line with thinkers who have suggested that people may fail, through a lack of belief or imagination, to identify with their future selves (Parfit 1971; Schelling 1984), we propose that allowing people to interact with age-progressed renderings of themselves will cause them to allocate more resources toward the future. In four studies, participants interacted with realistic computer renderings of their future selves using immersive virtual reality hardware and interactive decision aids. In all cases, those who interacted with virtual future selves exhibited an increased tendency to accept later monetary rewards over immediate ones. PMID:24634544

  1. 3D-TV System with Depth-Image-Based Rendering Architectures, Techniques and Challenges

    CERN Document Server

    Zhao, Yin; Yu, Lu; Tanimoto, Masayuki

    2013-01-01

    Riding on the success of 3D cinema blockbusters and advances in stereoscopic display technology, 3D video applications have gathered momentum in recent years. 3D-TV System with Depth-Image-Based Rendering: Architectures, Techniques and Challenges surveys depth-image-based 3D-TV systems, which are expected to be put into applications in the near future. Depth-image-based rendering (DIBR) significantly enhances the 3D visual experience compared to stereoscopic systems currently in use. DIBR techniques make it possible to generate additional viewpoints using 3D warping techniques to adjust the perceived depth of stereoscopic videos and provide for auto-stereoscopic displays that do not require glasses for viewing the 3D image.   The material includes a technical review and literature survey of components and complete systems, solutions for technical issues, and implementation of prototypes. The book is organized into four sections: System Overview, Content Generation, Data Compression and Transmission, and 3D V...

  2. INCREASING SAVING BEHAVIOR THROUGH AGE-PROGRESSED RENDERINGS OF THE FUTURE SELF.

    Science.gov (United States)

    Hershfield, Hal E; Goldstein, Daniel G; Sharpe, William F; Fox, Jesse; Yeykelis, Leo; Carstensen, Laura L; Bailenson, Jeremy N

    2011-11-01

    Many people fail to save what they need to for retirement (Munnell, Webb, and Golub-Sass 2009). Research on excessive discounting of the future suggests that removing the lure of immediate rewards by pre-committing to decisions, or elaborating the value of future rewards can both make decisions more future-oriented. In this article, we explore a third and complementary route, one that deals not with present and future rewards, but with present and future selves. In line with thinkers who have suggested that people may fail, through a lack of belief or imagination, to identify with their future selves (Parfit 1971; Schelling 1984), we propose that allowing people to interact with age-progressed renderings of themselves will cause them to allocate more resources toward the future. In four studies, participants interacted with realistic computer renderings of their future selves using immersive virtual reality hardware and interactive decision aids. In all cases, those who interacted with virtual future selves exhibited an increased tendency to accept later monetary rewards over immediate ones.

  3. Virtual endoscopy and 3D volume rendering in the management of frontal sinus fractures.

    Science.gov (United States)

    Belina, Stanko; Cuk, Viseslav; Klapan, Ivica

    2009-12-01

    Frontal sinus fractures (FSF) are commonly caused by traffic accidents, assaults, industrial accidents and gunshot wounds. Classical roentgenography has high proportion of false negative findings in cases of FSF and is not particularly useful in examining the severity of damage to the frontal sinus posterior table and the nasofrontal duct region. High resolution computed tomography was inavoidable during the management of such patients but it may produce large quantity of 2D images. Postprocessing of datasets acquired by high resolution computer tomography from patients with severe head trauma may offer a valuable additional help in diagnostics and surgery planning. We performed virtual endoscopy (VE) and 3D volume rendering (3DVR) on high resolution CT data acquired from a 54-year-old man with with both anterior and posterior frontal sinus wall fracture in order to demonstrate advantages and disadvantages of these methods. Data acquisition was done by Siemens Somatom Emotion scanner and postprocessing was performed with Syngo 2006G software. VE and 3DVR were performed in a man who suffered blunt trauma to his forehead and nose in an traffic accident. Left frontal sinus anterior wall fracture without dislocation and fracture of tabula interna with dislocation were found. 3D position and orientation of fracture lines were shown in by 3D rendering software. We concluded that VE and 3DVR can clearly display the anatomic structure of the paranasal sinuses and nasopharyngeal cavity, revealing damage to the sinus wall caused by a fracture and its relationship to surrounding anatomical structures.

  4. Radionuclide cisternography: SPECT and 3D-rendering. Radionuklidzisternographie: SPECT- und 3D-Technik

    Energy Technology Data Exchange (ETDEWEB)

    Henkes, H; Huber, G; Piepgras, U [Universitaet des Saarlandes, Homburg/Saar (Germany, F.R.). Abt. fuer Neuroradiologie; Hierholzer, J [Freie Univ. Berlin (Germany, F.R.). Strahlenklinik und Poliklinik; Cordes, M [British Columbia Univ., Vancouver, BC (Canada). Belzberg Lab. of Neuroscience

    1991-10-01

    Radionuclide cisternography is indicated in the clinical work-up for hydrocephalus, when searching for CSF leaks, and when testing whether or not intracranial cystic lesions are communicating with the adjacent subarachnoid space. This paper demonstrates the feasibility and diagnostic value of SPECT and subsequent 3D surface rendering in addition to conventional rectilinear CSF imaging in eight patients. Planar images allowed the evaluation of CSF circulation and the detection of CSF fistula. They were advantageous in examinations 48 h after application of {sup 111}In-DTPA. SPECT scans, generated 4-24 h after tracer application, were superior in the delineation of basal cisterns, especially in early scans; this was helpful in patients with pooling due to CSF fistula and in cystic lesions near the skull base. A major drawback was the limited image quality of delayed scans, when the SPECT data were degraded by a low count rate. 3D surface rendering was easily feasible from SPECT data and yielded high quality images. The presentation of the spatial distribution of nuclide-contaminated CSF proved especially helpful in the area of the basal cisterns. (orig.).

  5. Ethylene signaling renders the jasmonate response of Arabidopsis insensitive to future suppression by salicylic Acid.

    Science.gov (United States)

    Leon-Reyes, Antonio; Du, Yujuan; Koornneef, Annemart; Proietti, Silvia; Körbes, Ana P; Memelink, Johan; Pieterse, Corné M J; Ritsema, Tita

    2010-02-01

    Cross-talk between jasmonate (JA), ethylene (ET), and Salicylic acid (SA) signaling is thought to operate as a mechanism to fine-tune induced defenses that are activated in response to multiple attackers. Here, 43 Arabidopsis genotypes impaired in hormone signaling or defense-related processes were screened for their ability to express SA-mediated suppression of JA-responsive gene expression. Mutant cev1, which displays constitutive expression of JA and ET responses, appeared to be insensitive to SA-mediated suppression of the JA-responsive marker genes PDF1.2 and VSP2. Accordingly, strong activation of JA and ET responses by the necrotrophic pathogens Botrytis cinerea and Alternaria brassicicola prior to SA treatment counteracted the ability of SA to suppress the JA response. Pharmacological assays, mutant analysis, and studies with the ET-signaling inhibitor 1-methylcyclopropene revealed that ET signaling renders the JA response insensitive to subsequent suppression by SA. The APETALA2/ETHYLENE RESPONSE FACTOR transcription factor ORA59, which regulates JA/ET-responsive genes such as PDF1.2, emerged as a potential mediator in this process. Collectively, our results point to a model in which simultaneous induction of the JA and ET pathway renders the plant insensitive to future SA-mediated suppression of JA-dependent defenses, which may prioritize the JA/ET pathway over the SA pathway during multi-attacker interactions.

  6. Signal Processing Implementation and Comparison of Automotive Spatial Sound Rendering Strategies

    Directory of Open Access Journals (Sweden)

    Bai MingsianR

    2009-01-01

    Full Text Available Design and implementation strategies of spatial sound rendering are investigated in this paper for automotive scenarios. Six design methods are implemented for various rendering modes with different number of passengers. Specifically, the downmixing algorithms aimed at balancing the front and back reproductions are developed for the 5.1-channel input. Other five algorithms based on inverse filtering are implemented in two approaches. The first approach utilizes binaural (Head-Related Transfer Functions HRTFs measured in the car interior, whereas the second approach named the point-receiver model targets a point receiver positioned at the center of the passenger's head. The proposed processing algorithms were compared via objective and subjective experiments under various listening conditions. Test data were processed by the multivariate analysis of variance (MANOVA method and the least significant difference (Fisher's LSD method as a post hoc test to justify the statistical significance of the experimental data. The results indicate that inverse filtering algorithms are preferred for the single passenger mode. For the multipassenger mode, however, downmixing algorithms generally outperformed the other processing techniques.

  7. Complex adaptation-based LDR image rendering for 3D image reconstruction

    Science.gov (United States)

    Lee, Sung-Hak; Kwon, Hyuk-Ju; Sohng, Kyu-Ik

    2014-07-01

    A low-dynamic tone-compression technique is developed for realistic image rendering that can make three-dimensional (3D) images similar to realistic scenes by overcoming brightness dimming in the 3D display mode. The 3D surround provides varying conditions for image quality, illuminant adaptation, contrast, gamma, color, sharpness, and so on. In general, gain/offset adjustment, gamma compensation, and histogram equalization have performed well in contrast compression; however, as a result of signal saturation and clipping effects, image details are removed and information is lost on bright and dark areas. Thus, an enhanced image mapping technique is proposed based on space-varying image compression. The performance of contrast compression is enhanced with complex adaptation in a 3D viewing surround combining global and local adaptation. Evaluating local image rendering in view of tone and color expression, noise reduction, and edge compensation confirms that the proposed 3D image-mapping model can compensate for the loss of image quality in the 3D mode.

  8. In Vivo CT Direct Volume Rendering: A Three-Dimensional Anatomical Description of the Heart

    International Nuclear Information System (INIS)

    Cutroneo, Giuseppina; Bruschetta, Daniele; Trimarchi, Fabio; Cacciola, Alberto; Cinquegrani, Maria; Duca, Antonio; Rizzo, Giuseppina; Alati, Emanuela; Gaeta, Michele; Milardi, Demetrio

    2016-01-01

    Since cardiac anatomy continues to play an important role in the practice of medicine and in the development of medical devices, the study of the heart in three dimensions is particularly useful to understand its real structure, function and proper location in the body. This study demonstrates a fine use of direct volume rendering, processing the data set images obtained by Computed Tomography (CT) of the heart of 5 subjects with age range between 18 and 42 years (2 male, 3 female), with no history of any overt cardiac disease. The cardiac structure in CT images was first extracted from the thorax by marking manually the regions of interest on the computer, and then it was stacked to create new volumetric data. The use of a specific algorithm allowed us to observe with a good perception of depth the heart and the skeleton of the thorax at the same time. Besides, in all examined subjects, it was possible to depict its structure and its position within the body and to study the integrity of papillary muscles, the fibrous tissue of cardiac valve and chordae tendineae and the course of coronary arteries. Our results demonstrated that one of the greatest advantages of algorithmic modifications of direct volume rendering parameters is that this method provides much necessary information in a single radiologic study. It implies a better accuracy in the study of the heart, being complementary to other diagnostic methods and facilitating the therapeutic plans

  9. Efficient Algorithms for Real-Time GPU Volumetric Cloud Rendering with Enhanced Geometry

    Directory of Open Access Journals (Sweden)

    Carlos Jiménez de Parga

    2018-04-01

    Full Text Available This paper presents several new techniques for volumetric cloud rendering using efficient algorithms and data structures based on ray-tracing methods for cumulus generation, achieving an optimum balance between realism and performance. These techniques target applications such as flight simulations, computer games, and educational software, even with conventional graphics hardware. The contours of clouds are defined by implicit mathematical expressions or triangulated structures inside which volumetric rendering is performed. Novel techniques are used to reproduce the asymmetrical nature of clouds and the effects of light-scattering, with low computing costs. The work includes a new method to create randomized fractal clouds using a recursive grammar. The graphical results are comparable to those produced by state-of-the-art, hyper-realistic algorithms. These methods provide real-time performance, and are superior to particle-based systems. These outcomes suggest that our methods offer a good balance between realism and performance, and are suitable for use in the standard graphics industry.

  10. 3D cinematic rendering of the calvarium, maxillofacial structures, and skull base: preliminary observations.

    Science.gov (United States)

    Rowe, Steven P; Zinreich, S James; Fishman, Elliot K

    2018-06-01

    Three-dimensional (3D) visualizations of volumetric data from CT have gained widespread clinical acceptance and are an important method for evaluating complex anatomy and pathology. Recently, cinematic rendering (CR), a new 3D visualization methodology, has become available. CR utilizes a lighting model that allows for the production of photorealistic images from isotropic voxel data. Given how new this technique is, studies to evaluate its clinical utility and any potential advantages or disadvantages relative to other 3D methods such as volume rendering have yet to be published. In this pictorial review, we provide examples of normal calvarial, maxillofacial, and skull base anatomy and pathological conditions that highlight the potential for CR images to aid in patient evaluation and treatment planning. The highly detailed images and nuanced shadowing that are intrinsic to CR are well suited to the display of the complex anatomy in this region of the body. We look forward to studies with CR that will ascertain the ultimate value of this methodology to evaluate calvarium, maxillofacial, and skull base morphology as well as other complex anatomic structures.

  11. State of the Art in Transfer Functions for Direct Volume Rendering

    KAUST Repository

    Ljung, Patric

    2016-07-04

    A central topic in scientific visualization is the transfer function (TF) for volume rendering. The TF serves a fundamental role in translating scalar and multivariate data into color and opacity to express and reveal the relevant features present in the data studied. Beyond this core functionality, TFs also serve as a tool for encoding and utilizing domain knowledge and as an expression for visual design of material appearances. TFs also enable interactive volumetric exploration of complex data. The purpose of this state-of-the-art report (STAR) is to provide an overview of research into the various aspects of TFs, which lead to interpretation of the underlying data through the use of meaningful visual representations. The STAR classifies TF research into the following aspects: dimensionality, derived attributes, aggregated attributes, rendering aspects, automation, and user interfaces. The STAR concludes with some interesting research challenges that form the basis of an agenda for the development of next generation TF tools and methodologies. © 2016 The Author(s) Computer Graphics Forum © 2016 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

  12. Comparison of L-system applications towards plant modelling, music rendering and score generation using visual language programming

    Science.gov (United States)

    Lim, Chen Kim; Tan, Kian Lam; Yusran, Hazwanni; Suppramaniam, Vicknesh

    2017-10-01

    Visual language or visual representation has been used in the past few years in order to express the knowledge in graphic. One of the important graphical elements is fractal and L-Systems is a mathematic-based grammatical model for modelling cell development and plant topology. From the plant model, L-Systems can be interpreted as music sound and score. In this paper, LSound which is a Visual Language Programming (VLP) framework has been developed to model plant to music sound and generate music score and vice versa. The objectives of this research has three folds: (i) To expand the grammar dictionary of L-Systems music based on visual programming, (ii) To design and produce a user-friendly and icon based visual language framework typically for L-Systems musical score generation which helps the basic learners in musical field and (iii) To generate music score from plant models and vice versa using L-Systems method. This research undergoes a four phases methodology where the plant is first modelled, then the music is interpreted, followed by the output of music sound through MIDI and finally score is generated. LSound is technically compared to other existing applications in the aspects of the capability of modelling the plant, rendering the music and generating the sound. It has been found that LSound is a flexible framework in which the plant can be easily altered through arrow-based programming and the music score can be altered through the music symbols and notes. This work encourages non-experts to understand L-Systems and music hand-in-hand.

  13. Pulmonary nodules: sensitivity of maximum intensity projection versus that of volume rendering of 3D multidetector CT data

    NARCIS (Netherlands)

    Peloschek, Philipp; Sailer, Johannes; Weber, Michael; Herold, Christian J.; Prokop, Mathias; Schaefer-Prokop, Cornelia

    2007-01-01

    PURPOSE: To prospectively compare maximum intensity projection (MIP) and volume rendering (VR) of multidetector computed tomographic (CT) data for the detection of small intrapulmonary nodules. MATERIALS AND METHODS: This institutional review board-approved prospective study included 20 oncology

  14. Application of coupled nanoscale resonators for spectral sensing

    International Nuclear Information System (INIS)

    Nefedov, N

    2009-01-01

    In this paper we propose a method to perform tunable spectral sensing using globally inhibitory coupled oscillators. The suggested system may operate in the analog radio frequency (RF) domain without high speed ADC and heavy digital signal processing. Oscillator arrays may be made of imprecise elements such as nanoresonators. Provided there is a proper coupling, the system dynamics can be made stable despite the imprecision of the components. Global coupling could be implemented using a common load and controlled by digital means to tune the bandwidth. This method may be used for spectral sensing in cognitive radio terminals.

  15. Application of coupled nanoscale resonators for spectral sensing

    Energy Technology Data Exchange (ETDEWEB)

    Nefedov, N [Nokia Research Center, Hardturmstrasse 253, CH-8005 Zurich (Switzerland); Swiss Federal Institute of Technology Zurich (ETHZ), ISI Laboratory, Sternwartstrasse 7, CH-8092 Zuerich (Switzerland)], E-mail: nikolai.nefedov@nokia.com

    2009-04-08

    In this paper we propose a method to perform tunable spectral sensing using globally inhibitory coupled oscillators. The suggested system may operate in the analog radio frequency (RF) domain without high speed ADC and heavy digital signal processing. Oscillator arrays may be made of imprecise elements such as nanoresonators. Provided there is a proper coupling, the system dynamics can be made stable despite the imprecision of the components. Global coupling could be implemented using a common load and controlled by digital means to tune the bandwidth. This method may be used for spectral sensing in cognitive radio terminals.

  16. New elements

    International Nuclear Information System (INIS)

    Flerov, G.

    1976-01-01

    The history is briefly described of the investigation of superheavy elements at the Joint Institute for Nuclear Research at Dubna. The significance of the investigation is assessed from the point of view of the nuclear structure study and major problems encountered in experimental efforts are indicated. Current experimental methods aiming at the discovery or the production of superheavy nuclei with Z approximately 114 are listed. (I.W.)

  17. Long-term thermophilic mono-digestion of rendering wastes and co-digestion with potato pulp

    International Nuclear Information System (INIS)

    Bayr, S.; Ojanperä, M.; Kaparaju, P.; Rintala, J.

    2014-01-01

    Highlights: • Rendering wastes’ mono-digestion and co-digestion with potato pulp were studied. • CSTR process with OLR of 1.5 kg VS/m 3 d, HRT of 50 d was unstable in mono-digestion. • Free NH 3 inhibited mono-digestion of rendering wastes. • CSTR process with OLR of 1.5 kg VS/m 3 d, HRT of 50 d was stable in co-digestion. • Co-digestion increased methane yield somewhat compared to mono-digestion. - Abstract: In this study, mono-digestion of rendering wastes and co-digestion of rendering wastes with potato pulp were studied for the first time in continuous stirred tank reactor (CSTR) experiments at 55 °C. Rendering wastes have high protein and lipid contents and are considered good substrates for methane production. However, accumulation of digestion intermediate products viz., volatile fatty acids (VFAs), long chain fatty acids (LCFAs) and ammonia nitrogen (NH 4 -N and/or free NH 3 ) can cause process imbalance during the digestion. Mono-digestion of rendering wastes at an organic loading rate (OLR) of 1.5 kg volatile solids (VS)/m 3 d and hydraulic retention time (HRT) of 50 d was unstable and resulted in methane yields of 450 dm 3 /kg VS fed . On the other hand, co-digestion of rendering wastes with potato pulp (60% wet weight, WW) at the same OLR and HRT improved the process stability and increased methane yields (500–680 dm 3 /kg VS fed ). Thus, it can be concluded that co-digestion of rendering wastes with potato pulp could improve the process stability and methane yields from these difficult to treat industrial waste materials

  18. Long-term thermophilic mono-digestion of rendering wastes and co-digestion with potato pulp

    Energy Technology Data Exchange (ETDEWEB)

    Bayr, S., E-mail: suvi.bayr@jyu.fi; Ojanperä, M.; Kaparaju, P.; Rintala, J.

    2014-10-15

    Highlights: • Rendering wastes’ mono-digestion and co-digestion with potato pulp were studied. • CSTR process with OLR of 1.5 kg VS/m{sup 3} d, HRT of 50 d was unstable in mono-digestion. • Free NH{sub 3} inhibited mono-digestion of rendering wastes. • CSTR process with OLR of 1.5 kg VS/m{sup 3} d, HRT of 50 d was stable in co-digestion. • Co-digestion increased methane yield somewhat compared to mono-digestion. - Abstract: In this study, mono-digestion of rendering wastes and co-digestion of rendering wastes with potato pulp were studied for the first time in continuous stirred tank reactor (CSTR) experiments at 55 °C. Rendering wastes have high protein and lipid contents and are considered good substrates for methane production. However, accumulation of digestion intermediate products viz., volatile fatty acids (VFAs), long chain fatty acids (LCFAs) and ammonia nitrogen (NH{sub 4}-N and/or free NH{sub 3}) can cause process imbalance during the digestion. Mono-digestion of rendering wastes at an organic loading rate (OLR) of 1.5 kg volatile solids (VS)/m{sup 3} d and hydraulic retention time (HRT) of 50 d was unstable and resulted in methane yields of 450 dm{sup 3}/kg VS{sub fed}. On the other hand, co-digestion of rendering wastes with potato pulp (60% wet weight, WW) at the same OLR and HRT improved the process stability and increased methane yields (500–680 dm{sup 3}/kg VS{sub fed}). Thus, it can be concluded that co-digestion of rendering wastes with potato pulp could improve the process stability and methane yields from these difficult to treat industrial waste materials.

  19. Volumetric three-dimensional reconstruction and segmentation of spectral-domain OCT.

    Science.gov (United States)

    Aaker, Grant D; Gracia, Luis; Myung, Jane S; Borcherding, Vanessa; Banfelder, Jason R; D'Amico, Donald J; Kiss, Szilárd

    2011-07-01

    Despite advances in optical coherence tomography (OCT), three-dimensional (3D) renderings of OCT images remain limited to scanning consecutive two-dimensional (2D) OCT slices. The authors describe a method of reconstructing 2D OCT data for 3D retinal analysis and visualization in a Computer Assisted Virtual Environment (CAVE). Using customized signal processing software, raw data from 2D slice-based spectral-domain OCT images were rendered into high-resolution 3D images for segmentation and quantification analysis. Reconstructed OCT images were projected onto a four-walled space and viewed through stereoscopic glasses, resulting in a virtual reality perception of the retina. These 3D retinal renderings offer a novel method for segmentation and isolation of volumetric images. The ability to manipulate the images in a virtual reality environment allows visualization of complex spatial relationships that may aid our understanding of retinal pathology. More importantly, these 3D retinal renderings can be viewed, manipulated, and analyzed on traditional 2D monitors independent of the CAVE. Copyright 2011, SLACK Incorporated.

  20. [Hybrid 3-D rendering of the thorax and surface-based virtual bronchoscopy in surgical and interventional therapy control].

    Science.gov (United States)

    Seemann, M D; Gebicke, K; Luboldt, W; Albes, J M; Vollmar, J; Schäfer, J F; Beinert, T; Englmeier, K H; Bitzer, M; Claussen, C D

    2001-07-01

    The aim of this study was to demonstrate the possibilities of a hybrid rendering method, the combination of a color-coded surface and volume rendering method, with the feasibility of performing surface-based virtual endoscopy with different representation models in the operative and interventional therapy control of the chest. In 6 consecutive patients with partial lung resection (n = 2) and lung transplantation (n = 4) a thin-section spiral computed tomography of the chest was performed. The tracheobronchial system and the introduced metallic stents were visualized using a color-coded surface rendering method. The remaining thoracic structures were visualized using a volume rendering method. For virtual bronchoscopy, the tracheobronchial system was visualized using a triangle surface model, a shaded-surface model and a transparent shaded-surface model. The hybrid 3D visualization uses the advantages of both the color-coded surface and volume rendering methods and facilitates a clear representation of the tracheobronchial system and the complex topographical relationship of morphological and pathological changes without loss of diagnostic information. Performing virtual bronchoscopy with the transparent shaded-surface model facilitates a reasonable to optimal, simultaneous visualization and assessment of the surface structure of the tracheobronchial system and the surrounding mediastinal structures and lesions. Hybrid rendering relieve the morphological assessment of anatomical and pathological changes without the need for time-consuming detailed analysis and presentation of source images. Performing virtual bronchoscopy with a transparent shaded-surface model offers a promising alternative to flexible fiberoptic bronchoscopy.

  1. Real-time 3-dimensional fetal echocardiography with an instantaneous volume-rendered display: early description and pictorial essay.

    Science.gov (United States)

    Sklansky, Mark S; DeVore, Greggory R; Wong, Pierre C

    2004-02-01

    Random fetal motion, rapid fetal heart rates, and cumbersome processing algorithms have limited reconstructive approaches to 3-dimensional fetal cardiac imaging. Given the recent development of real-time, instantaneous volume-rendered sonographic displays of volume data, we sought to apply this technology to fetal cardiac imaging. We obtained 1 to 6 volume data sets on each of 30 fetal hearts referred for formal fetal echocardiography. Each volume data set was acquired over 2 to 8 seconds and stored on the system's hard drive. Rendered images were subsequently processed to optimize translucency, smoothing, and orientation and cropped to reveal "surgeon's eye views" of clinically relevant anatomic structures. Qualitative comparison was made with conventional fetal echocardiography for each subject. Volume-rendered displays identified all major abnormalities but failed to identify small ventricular septal defects in 2 patients. Important planes and views not visualized during the actual scans were generated with minimal processing of rendered image displays. Volume-rendered displays tended to have slightly inferior image quality compared with conventional 2-dimensional images. Real-time 3-dimensional echocardiography with instantaneous volume-rendered displays of the fetal heart represents a new approach to fetal cardiac imaging with tremendous clinical potential.

  2. Substitution dynamical systems spectral analysis

    CERN Document Server

    Queffélec, Martine

    2010-01-01

    This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...

  3. Spectral characterization of natural backgrounds

    Science.gov (United States)

    Winkelmann, Max

    2017-10-01

    As the distribution and use of hyperspectral sensors is constantly increasing, the exploitation of spectral features is a threat for camouflaged objects. To improve camouflage materials at first the spectral behavior of backgrounds has to be known to adjust and optimize the spectral reflectance of camouflage materials. In an international effort, the NATO CSO working group SCI-295 "Development of Methods for Measurements and Evaluation of Natural Background EO Signatures" is developing a method how this characterization of backgrounds has to be done. It is obvious that the spectral characterization of a background will be quite an effort. To compare and exchange data internationally the measurements will have to be done in a similar way. To test and further improve this method an international field trial has been performed in Storkow, Germany. In the following we present first impressions and lessons learned from this field campaign and describe the data that has been measured.

  4. Adiabatic theorem and spectral concentration

    International Nuclear Information System (INIS)

    Nenciu, G.

    1981-01-01

    The spectral concentration of arbitrary order, for the Stark effect is proved to exist for a large class of Hamiltonians appearing in nonrelativistic and relativistic quantum mechanics. The results are consequences of an abstract theorem about the spectral concentration for self-ad oint operators. A general form of the adiabatic theorem of quantum mechanics, generalizing an earlier result of the author as well as some results of Lenard, is also proved [ru

  5. Analytical characterization of technical animal fat from a rendering plant; Chemisch-analytische Charakterisierung technischen tierischen Fettes aus einer Tierkoerperbeseitigungsanstalt

    Energy Technology Data Exchange (ETDEWEB)

    Bahadir, M.; Jopke, P.; Matthies, B.; Schmidt-Naedler, C.; Wichmann, H. [Technische Univ. Braunschweig (Germany). Inst. fuer Oekologische Chemie und Abfallanalytik; Bock, R.; Dettmer, T.; Hesselbach, J. [Technische Univ. Braunschweig (Germany). Inst. fuer Werkzeugmaschinen und Fertigungstechnik; Falk, O.; Meyer-Pittroff, R. [Technische Univ. Muenchen, Freising-Weihenstephan (Germany). Lehrstuhl fuer Energie- und Umwelttechnik der Lebensmittelindustrie

    2004-07-01

    Aims and Scope. German rendering plants produce 300,000 tons of animal fat per year. Until recently, these raw products have been in wide use as nutritional additive for cattle and other animals fodder but now they have been banned due to their assumed role in BSE infection. Therefore, alternative fields of usage are required. In this context the Deutsche Bundesstiftung Umwelt (DBU) is sponsoring a joint research project which deals with the production and testing of cooling lubricants based on animal fat esters. Methods. In a first step, characteristics and quality of the animal fat were analyzed and monitored for a whole year in order to identify e.g. seasonal variations. The investigations covered the following fat specific and trace analytical parameters: total contamination, sulfates ash, water content, peroxide number, iodine value, kinematical viscosity, neutralisation number (free fatty acids), fatty acid spectra, elements / heavy metals (Al, B, Ca, Cd, Cr, Cu, Fe, K, Mo, Mn, Na, Ni, P, Pb, S, Sn, V, W and Zn), polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzo-dioxins and polychlorinated dibenzofurans. Results. Valuable hints on the design of the technical process of fatty acid methylesters production were gained by regarding the fat specific parameters. (orig.) [German] Hintergrund und Ziel. Von den deutschen Tierkoerperbeseitigungsanstalten werden z.Z. rund 300.000 t/a technisches tierisches Fett produziert. Ausgeloest durch die BSE-Krise wird dieser Rohstoff nicht mehr als Tierfutterergaenzungsmittel eingesetzt. Nun wird nach neuen Verwertungswegen fuer diese Fette gesucht. In diesem Zusammenhang wird von der DBU ein Verbundprojekt finanziert, in dessen Rahmen durch Umesterung der Fette Grundoele fuer Kuehlschmierstoffe (KSS) hergestellt und die KSS-Produkte in der spanenden Bearbeitung von Metallen in der industriellen Praxis getestet werden sollen. Methoden. Als erster Schritt sollten durch chemisch

  6. Robust and transferable quantification of NMR spectral quality using IROC analysis

    Science.gov (United States)

    Zambrello, Matthew A.; Maciejewski, Mark W.; Schuyler, Adam D.; Weatherby, Gerard; Hoch, Jeffrey C.

    2017-12-01

    Non-Fourier methods are increasingly utilized in NMR spectroscopy because of their ability to handle nonuniformly-sampled data. However, non-Fourier methods present unique challenges due to their nonlinearity, which can produce nonrandom noise and render conventional metrics for spectral quality such as signal-to-noise ratio unreliable. The lack of robust and transferable metrics (i.e. applicable to methods exhibiting different nonlinearities) has hampered comparison of non-Fourier methods and nonuniform sampling schemes, preventing the identification of best practices. We describe a novel method, in situ receiver operating characteristic analysis (IROC), for characterizing spectral quality based on the Receiver Operating Characteristic curve. IROC utilizes synthetic signals added to empirical data as "ground truth", and provides several robust scalar-valued metrics for spectral quality. This approach avoids problems posed by nonlinear spectral estimates, and provides a versatile quantitative means of characterizing many aspects of spectral quality. We demonstrate applications to parameter optimization in Fourier and non-Fourier spectral estimation, critical comparison of different methods for spectrum analysis, and optimization of nonuniform sampling schemes. The approach will accelerate the discovery of optimal approaches to nonuniform sampling experiment design and non-Fourier spectrum analysis for multidimensional NMR.

  7. A Screen Space GPGPU Surface LIC Algorithm for Distributed Memory Data Parallel Sort Last Rendering Infrastructures

    Energy Technology Data Exchange (ETDEWEB)

    Loring, Burlen; Karimabadi, Homa; Rortershteyn, Vadim

    2014-07-01

    The surface line integral convolution(LIC) visualization technique produces dense visualization of vector fields on arbitrary surfaces. We present a screen space surface LIC algorithm for use in distributed memory data parallel sort last rendering infrastructures. The motivations for our work are to support analysis of datasets that are too large to fit in the main memory of a single computer and compatibility with prevalent parallel scientific visualization tools such as ParaView and VisIt. By working in screen space using OpenGL we can leverage the computational power of GPUs when they are available and run without them when they are not. We address efficiency and performance issues that arise from the transformation of data from physical to screen space by selecting an alternate screen space domain decomposition. We analyze the algorithm's scaling behavior with and without GPUs on two high performance computing systems using data from turbulent plasma simulations.

  8. MRI of the labyrinth with volume rendering for cochlear implants candidates

    International Nuclear Information System (INIS)

    Sakata, Motomichi; Harada, Kuniaki; Shirase, Ryuji; Suzuki, Junpei; Nagahama, Hiroshi

    2009-01-01

    We demonstrated three-dimensional models of the labyrinth by volume rendering (VR) in preoperative assessment for cochlear implantation. MRI data sets were acquired in selected subjects using three-dimensional-fast spin echo sequences (3D-FSE). We produced the three-dimensional models of the labyrinth from axial heavily T2-weighted images. The three-dimensional models distinguished the scala tympani and scala vestibuli and provided multidirectional images. The optimal threshold three-dimensional models clearly showed the focal region of signal loss in the cochlear turns (47.1%) and the presence of inner ear anomalies (17.3%) in our series of patients. This study was concluded that these three-dimensional models by VR provide the oto-surgeon with precise, detailed, and easily interpreted information about the cochlear turns for cochlear implants candidates. (author)

  9. Screen Space Ambient Occlusion Based Multiple Importance Sampling for Real-Time Rendering

    Science.gov (United States)

    Zerari, Abd El Mouméne; Babahenini, Mohamed Chaouki

    2018-03-01

    We propose a new approximation technique for accelerating the Global Illumination algorithm for real-time rendering. The proposed approach is based on the Screen-Space Ambient Occlusion (SSAO) method, which approximates the global illumination for large, fully dynamic scenes at interactive frame rates. Current algorithms that are based on the SSAO method suffer from difficulties due to the large number of samples that are required. In this paper, we propose an improvement to the SSAO technique by integrating it with a Multiple Importance Sampling technique that combines a stratified sampling method with an importance sampling method, with the objective of reducing the number of samples. Experimental evaluation demonstrates that our technique can produce high-quality images in real time and is significantly faster than traditional techniques.

  10. Rendering Intelligence at Physical Layer for Smart Addressing and Multiple Access

    DEFF Research Database (Denmark)

    Sanyal, Rajarshi; Prasad, Ramjee; Cianca, Ernestina

    2010-01-01

    addressing of a node. For a typical closed user group type of network, we propose a multiple access mechanism and network topology which will not only eliminate the need of intelligent core network equipments in the network area , but to use this intelligent physical layer to directly reach any node over......The primary objective of this work is to propose a technique of wireless communication, where we render intelligence to the physical layer. We aim to realize a physical layer that can take part in some processes which is otherwise confined to higher layer signalling activities, like for example...... the fundamentals behind the proposed multiple access scheme and draws out the benefits compared to the existing multiple access processes based on cellular approach....

  11. Chromium: A Stress-Processing Framework for Interactive Rendering on Clusters

    International Nuclear Information System (INIS)

    Humphreys, G.; Houston, M.; Ng, Y.-R.; Frank, R.; Ahern, S.; Kirchner, P.D.; Klosowski, J.T.

    2002-01-01

    We describe Chromium, a system for manipulating streams of graphics API commands on clusters of workstations. Chromium's stream filters can be arranged to create sort-first and sort-last parallel graphics architectures that, in many cases, support the same applications while using only commodity graphics accelerators. In addition, these stream filters can be extended programmatically, allowing the user to customize the stream transformations performed by nodes in a cluster. Because our stream processing mechanism is completely general, any cluster-parallel rendering algorithm can be either implemented on top of or embedded in Chromium. In this paper, we give examples of real-world applications that use Chromium to achieve good scalability on clusters of workstations, and describe other potential uses of this stream processing technology. By completely abstracting the underlying graphics architecture, network topology, and API command processing semantics, we allow a variety of applications to run in different environments

  12. The Role of the Patrimonial Result Account in Rendering Performance in the Secondary Educational Institutions

    Directory of Open Access Journals (Sweden)

    Daniela Vitan

    2016-01-01

    Full Text Available Through its tools, in particular through patrimonial result account, accounting gives information about the performance in the secondary educational institutions and beyond. In the work ”Informational valence regarding the role of the patrimonial result account in rendering performance at secondary educational institutions” it is presented an analysis model of the performance in the pre-university education institutions based on the economic-financial indicators. These indicator simply an analysis of the dynamics and structure of revenues, costs, results and enable the knowledge of the resource management in order to cover expenses from the revenue, their evolution and their total balance. The analysis was based on hypothetical data over a period of two years, and after this period it was determined that the institution has managed to maintain its level of efficiency in resource management.

  13. Feed-forward volume rendering algorithm for moderately parallel MIMD machines

    Science.gov (United States)

    Yagel, Roni

    1993-01-01

    Algorithms for direct volume rendering on parallel and vector processors are investigated. Volumes are transformed efficiently on parallel processors by dividing the data into slices and beams of voxels. Equal sized sets of slices along one axis are distributed to processors. Parallelism is achieved at two levels. Because each slice can be transformed independently of others, processors transform their assigned slices with no communication, thus providing maximum possible parallelism at the first level. Within each slice, consecutive beams are incrementally transformed using coherency in the transformation computation. Also, coherency across slices can be exploited to further enhance performance. This coherency yields the second level of parallelism through the use of the vector processing or pipelining. Other ongoing efforts include investigations into image reconstruction techniques, load balancing strategies, and improving performance.

  14. Scene reassembly after multimodal digitization and pipeline evaluation using photorealistic rendering

    DEFF Research Database (Denmark)

    Stets, Jonathan Dyssel; Dal Corso, Alessandro; Nielsen, Jannik Boll

    2017-01-01

    of the lighting environment. This enables pixelwise comparison of photographs of the real scene with renderings of the digital version of the scene. Such quantitative evaluation is useful for verifying acquired material appearance and reconstructed surface geometry, which is an important aspect of digital content......Transparent objects require acquisition modalities that are very different from the ones used for objects with more diffuse reflectance properties. Digitizing a scene where objects must be acquired with different modalities requires scene reassembly after reconstruction of the object surfaces....... This reassembly of a scene that was picked apart for scanning seems unexplored. We contribute with a multimodal digitization pipeline for scenes that require this step of reassembly. Our pipeline includes measurement of bidirectional reflectance distribution functions and high dynamic range imaging...

  15. Color design model of high color rendering index white-light LED module.

    Science.gov (United States)

    Ying, Shang-Ping; Fu, Han-Kuei; Hsieh, Hsin-Hsin; Hsieh, Kun-Yang

    2017-05-10

    The traditional white-light light-emitting diode (LED) is packaged with a single chip and a single phosphor but has a poor color rendering index (CRI). The next-generation package comprises two chips and a single phosphor, has a high CRI, and retains high luminous efficacy. This study employs two chips and two phosphors to improve the diode's color tunability with various proportions of two phosphors and various densities of phosphor in the silicone used. A color design model is established for color fine-tuning of the white-light LED module. The maximum difference between the measured and color-design-model simulated CIE 1931 color coordinates is approximately 0.0063 around a correlated color temperature (CCT) of 2500 K. This study provides a rapid method to obtain the color fine-tuning of a white-light LED module with a high CRI and luminous efficacy.

  16. Three-dimensional range data compression using computer graphics rendering pipeline.

    Science.gov (United States)

    Zhang, Song

    2012-06-20

    This paper presents the idea of naturally encoding three-dimensional (3D) range data into regular two-dimensional (2D) images utilizing computer graphics rendering pipeline. The computer graphics pipeline provides a means to sample 3D geometry data into regular 2D images, and also to retrieve the depth information for each sampled pixel. The depth information for each pixel is further encoded into red, green, and blue color channels of regular 2D images. The 2D images can further be compressed with existing 2D image compression techniques. By this novel means, 3D geometry data obtained by 3D range scanners can be instantaneously compressed into 2D images, providing a novel way of storing 3D range data into its 2D counterparts. We will present experimental results to verify the performance of this proposed technique.

  17. Characterizing CDOM Spectral Variability Across Diverse Regions and Spectral Ranges

    Science.gov (United States)

    Grunert, Brice K.; Mouw, Colleen B.; Ciochetto, Audrey B.

    2018-01-01

    Satellite remote sensing of colored dissolved organic matter (CDOM) has focused on CDOM absorption (aCDOM) at a reference wavelength, as its magnitude provides insight into the underwater light field and large-scale biogeochemical processes. CDOM spectral slope, SCDOM, has been treated as a constant or semiconstant parameter in satellite retrievals of aCDOM despite significant regional and temporal variabilities. SCDOM and other optical metrics provide insights into CDOM composition, processing, food web dynamics, and carbon cycling. To date, much of this work relies on fluorescence techniques or aCDOM in spectral ranges unavailable to current and planned satellite sensors (e.g., global variability in SCDOM and fit deviations in the aCDOM spectra using the recently proposed Gaussian decomposition method. From this, we investigate if global variability in retrieved SCDOM and Gaussian components is significant and regionally distinct. We iteratively decreased the spectral range considered and analyzed the number, location, and magnitude of fitted Gaussian components to understand if a reduced spectral range impacts information obtained within a common spectral window. We compared the fitted slope from the Gaussian decomposition method to absorption-based indices that indicate CDOM composition to determine the ability of satellite-derived slope to inform the analysis and modeling of large-scale biogeochemical processes. Finally, we present implications of the observed variability for remote sensing of CDOM characteristics via SCDOM.

  18. Superheavy elements

    CERN Document Server

    Hofmann, S

    1999-01-01

    The outstanding aim of experimental investigations of heavy nuclei is the exploration of spherical 'SuperHeavy Elements' (SHEs). On the basis of the nuclear shell model, the next double magic shell-closure beyond sup 2 sup 0 sup 8 Pb is predicted at proton numbers between Z=114 and 126 and at neutron number N=184. All experimental efforts aiming at identifying SHEs (Z>=114) were negative so far. A highly sensitive search experiment was performed in November-December 1995 at SHIP. The isotope sup 2 sup 9 sup 0 116 produced by 'radiative capture' was searched for in the course of a 33 days irradiation of a sup 2 sup 0 sup 8 Pb target with sup 8 sup 2 Se projectiles, however, only cross-section limits were measured. Positive results were obtained in experiments searching for elements from 110 to 112 using cold fusion and the 1n evaporation channel. The produced isotopes were unambiguously identified by means of alpha-alpha correlations. Not fission, but alpha emission is the dominant decay mode. The measurement ...

  19. Can thiolation render a low molecular weight polymer of just 20-kDa mucoadhesive?

    Science.gov (United States)

    Mahmood, Arshad; Bonengel, Sonja; Laffleur, Flavia; Ijaz, Muhammad; Idrees, Muneeb Ahmad; Hussain, Shah; Huck, Christian W; Matuszczak, Barbara; Bernkop-Schnürch, Andreas

    2016-01-01

    The objective was to investigate whether even low-molecular weight polymers (LMWPs) can be rendered mucoadhesive due to thiolation. Interceded by the double catalytic system carbodiimide/N-hydroxysuccinimide, cysteamine was covalently attached to a copolymer, poly(4-styrenesulfonic acid-co-maleic acid) (PSSA-MA) exhibiting a molecular weight of just 20 kDa. Depending on the amount of added N-hydroxysuccinimide and cysteamine, the resulting PSSA-MA-cysteamine (PC) conjugates exhibited increasing degree of thiolation, highest being "PC 2300" exhibiting 2300.16 ± 149.86 μmol thiol groups per gram of polymer (mean ± SD; n = 3). This newly developed thiolated polymer was evaluated regarding mucoadhesive, rheological and drug release properties as well from the toxicological point of view. Swelling behavior in 100 mM phosphate buffer pH 6.8 was improved up to 180-fold. Furthermore, due to thiolation, the mucoadhesive properties of the polymer were 240-fold improved. Rheological measurements of polymer/mucus mixtures confirmed results obtained by mucoadhesion studies. In comparison to unmodified polymer, PC 2300 showed 2.3-, 2.3- and 2.4-fold increase in dynamic viscosity, elastic modulus and viscous modulus, respectively. Sustained release of the model drug codeine HCl out of the thiomer was provided for 2.5 h (p polymer. Moreover, the thiomer was found non-toxic over Caco-2 cells for a period of 6- and 24-h exposure. Findings of the present study provide evidence that due to thiolation LMWPs can be rendered highly mucoadhesive as well as cohesive and that a controlled drug release out of such polymers can be provided.

  20. Post-processing methods of rendering and visualizing 3-D reconstructed tomographic images

    Energy Technology Data Exchange (ETDEWEB)

    Wong, S.T.C. [Univ. of California, San Francisco, CA (United States)

    1997-02-01

    The purpose of this presentation is to discuss the computer processing techniques of tomographic images, after they have been generated by imaging scanners, for volume visualization. Volume visualization is concerned with the representation, manipulation, and rendering of volumetric data. Since the first digital images were produced from computed tomography (CT) scanners in the mid 1970s, applications of visualization in medicine have expanded dramatically. Today, three-dimensional (3D) medical visualization has expanded from using CT data, the first inherently digital source of 3D medical data, to using data from various medical imaging modalities, including magnetic resonance scanners, positron emission scanners, digital ultrasound, electronic and confocal microscopy, and other medical imaging modalities. We have advanced from rendering anatomy to aid diagnosis and visualize complex anatomic structures to planning and assisting surgery and radiation treatment. New, more accurate and cost-effective procedures for clinical services and biomedical research have become possible by integrating computer graphics technology with medical images. This trend is particularly noticeable in current market-driven health care environment. For example, interventional imaging, image-guided surgery, and stereotactic and visualization techniques are now stemming into surgical practice. In this presentation, we discuss only computer-display-based approaches of volumetric medical visualization. That is, we assume that the display device available is two-dimensional (2D) in nature and all analysis of multidimensional image data is to be carried out via the 2D screen of the device. There are technologies such as holography and virtual reality that do provide a {open_quotes}true 3D screen{close_quotes}. To confine the scope, this presentation will not discuss such approaches.

  1. Post-processing methods of rendering and visualizing 3-D reconstructed tomographic images

    International Nuclear Information System (INIS)

    Wong, S.T.C.

    1997-01-01

    The purpose of this presentation is to discuss the computer processing techniques of tomographic images, after they have been generated by imaging scanners, for volume visualization. Volume visualization is concerned with the representation, manipulation, and rendering of volumetric data. Since the first digital images were produced from computed tomography (CT) scanners in the mid 1970s, applications of visualization in medicine have expanded dramatically. Today, three-dimensional (3D) medical visualization has expanded from using CT data, the first inherently digital source of 3D medical data, to using data from various medical imaging modalities, including magnetic resonance scanners, positron emission scanners, digital ultrasound, electronic and confocal microscopy, and other medical imaging modalities. We have advanced from rendering anatomy to aid diagnosis and visualize complex anatomic structures to planning and assisting surgery and radiation treatment. New, more accurate and cost-effective procedures for clinical services and biomedical research have become possible by integrating computer graphics technology with medical images. This trend is particularly noticeable in current market-driven health care environment. For example, interventional imaging, image-guided surgery, and stereotactic and visualization techniques are now stemming into surgical practice. In this presentation, we discuss only computer-display-based approaches of volumetric medical visualization. That is, we assume that the display device available is two-dimensional (2D) in nature and all analysis of multidimensional image data is to be carried out via the 2D screen of the device. There are technologies such as holography and virtual reality that do provide a open-quotes true 3D screenclose quotes. To confine the scope, this presentation will not discuss such approaches

  2. 3D reconstruction from X-ray fluoroscopy for clinical veterinary medicine using differential volume rendering

    International Nuclear Information System (INIS)

    Khongsomboon, K.; Hamamoto, Kazuhiko; Kondo, Shozo

    2007-01-01

    3D reconstruction from ordinary X-ray equipment which is not CT or MRI is required in clinical veterinary medicine. Authors have already proposed a 3D reconstruction technique from X-ray photograph to present bone structure. Although the reconstruction is useful for veterinary medicine, the technique has two problems. One is about exposure of X-ray and the other is about data acquisition process. An x-ray equipment which is not special one but can solve the problems is X-ray fluoroscopy. Therefore, in this paper, we propose a method for 3D-reconstruction from X-ray fluoroscopy for clinical veterinary medicine. Fluoroscopy is usually used to observe a movement of organ or to identify a position of organ for surgery by weak X-ray intensity. Since fluoroscopy can output a observed result as movie, the previous two problems which are caused by use of X-ray photograph can be solved. However, a new problem arises due to weak X-ray intensity. Although fluoroscopy can present information of not only bone structure but soft tissues, the contrast is very low and it is very difficult to recognize some soft tissues. It is very useful to be able to observe not only bone structure but soft tissues clearly by ordinary X-ray equipment in the field of clinical veterinary medicine. To solve this problem, this paper proposes a new method to determine opacity in volume rendering process. The opacity is determined according to 3D differential coefficient of 3D reconstruction. This differential volume rendering can present a 3D structure image of multiple organs volumetrically and clearly for clinical veterinary medicine. This paper shows results of simulation and experimental investigation of small dog and evaluation by veterinarians. (author)

  3. 3D-shaded surface rendering of gadolinium-enhanced MR angiography in congenital heart disease

    International Nuclear Information System (INIS)

    Okuda, S.; Kikinis, R.; Dumanli, H.; Geva, T.; Powell, A.J.; Chung, T.

    2000-01-01

    Background. Gadolinium-enhanced three-dimensional (3D) MR angiography is a useful imaging technique for patients with congenital heart disease. Objective. This study sought to determine the added value of creating 3D shaded surface displays compared to standard maximal intensity projection (MIP) and multiplanar reformatting (MPR) techniques when analyzing 3D MR angiography data. Materials and methods. Seventeen patients (range, 3 months to 51 years old) with a variety of congenital cardiovascular defects underwent gadolinium-enhanced 3D MR angiography of the thorax. Color-coded 3D shaded surface models were rendered from the image data using manual segmentation and computer-based algorithms. Models could be rotated, translocated, or zoomed interactively by the viewer. Information available from the 3D models was compared to analysis based on viewing standard MIP/MPR displays. Results. Median postprocessing time for the 3D models was 6 h (range, 3-25 h) compared to approximately 20 min for MIP/MPR viewing. No additional diagnostic information was gained from 3D model analysis. All major findings with MIP/MPR postprocessing were also apparent on the 3D models. Qualitatively, the 3D models were more easily interpreted and enabled adjacent vessels to be distinguished more readily. Conclusion. Routine use of 3D shaded surface reconstructions for visualization of contrast enhanced MR angiography in congenital heart disease cannot be recommended. 3D surface rendering may be more useful for presenting complex anatomy to an audience unfamiliar with congenital heart disease and as an educational tool. (orig.)

  4. Radical advancement in multi-spectral imaging for autonomous vehicles (UAVs, UGVs, and UUVs) using active compensation.

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Brian F.; Bagwell, Brett E.; Wick, David Victor

    2007-01-01

    The purpose of this LDRD was to demonstrate a compact, multi-spectral, refractive imaging systems using active optical compensation. Compared to a comparable, conventional lens system, our system has an increased operational bandwidth, provides for spectral selectivity and, non-mechanically corrects aberrations induced by the wavelength dependent properties of a passive refractive optical element (i.e. lens). The compact nature and low power requirements of the system lends itself to small platforms such as autonomous vehicles. In addition, the broad spectral bandwidth of our system would allow optimized performance for both day/night use, and the multi-spectral capability allows for spectral discrimination and signature identification.

  5. Fabrication of the polarization independent spectral beam combining grating

    Science.gov (United States)

    Liu, Quan; Jin, Yunxia; Wu, Jianhong; Guo, Peiliang

    2016-03-01

    Owing to damage, thermal issues, and nonlinear optical effects, the output power of fiber laser has been proven to be limited. Beam combining techniques are the attractive solutions to achieve high-power high-brightness fiber laser output. The spectral beam combining (SBC) is a promising method to achieve high average power output without influencing the beam quality. A polarization independent spectral beam combining grating is one of the key elements in the SBC. In this paper the diffraction efficiency of the grating is investigated by rigorous coupled-wave analysis (RCWA). The theoretical -1st order diffraction efficiency of the grating is more than 95% from 1010nm to 1080nm for both TE and TM polarizations. The fabrication tolerance is analyzed. The polarization independent spectral beam combining grating with the period of 1.04μm has been fabricated by holographic lithography - ion beam etching, which are within the fabrication tolerance.

  6. Spectral Hounsfield units: a new radiological concept

    International Nuclear Information System (INIS)

    Hurrell, Michael Anthony; Butler, Anthony Philip Howard; Cook, Nicholas James; Butler, Philip Howard; Ronaldson, J.P.; Zainon, Rafidah

    2012-01-01

    Computed tomography (CT) uses radiographical density to depict different materials; although different elements have different absorption fingerprints across the range of diagnostic X-ray energies, this spectral absorption information is lost in conventional CT. The recent development of dual energy CT (DECT) allows extraction of this information to a useful but limited extent. However, the advent of new photon counting chips that have energy resolution capabilities has put multi-energy or spectral CT (SCT) on the clinical horizon. This paper uses a prototype SCT system to demonstrate how CT density measurements vary with kilovoltage. While radiologists learn about linear attenuation curves during radiology training, they do not usually need a detailed understanding of this phenomenon in their clinical practice. However SCT requires a paradigm shift in how radiologists think about CT density. Because radiologists are already familiar with the Hounsfield Unit (HU), it is proposed that a modified HU be used that includes the mean energy used to obtain the image, as a conceptual bridge between conventional CT and SCT. A suggested format would be: HU keV . (orig.)

  7. A spectral analysis of rice grains

    International Nuclear Information System (INIS)

    McIlvaine, M.S.; Cua, F.T.; Navarro, E.F.

    1976-06-01

    With the advent of extensive nuclear testing and the development and use of highly potent pesticides and fertilizers, the hazardous threats of radioactive contamination due to fallout and to the absorption of pesticide residues have been given due consideration. Among the many forms of life exposed to these threats are food crops and among these is rice. Several rice grain samples - Japanese rice samples ''A'' and ''B'' submitted by the National Grains Authority (NGA) for analysis, random samples of rice being sold to the public at local markets, and ''black rice'' which were picked from along the shores of a Mindoro town were subjected to spectral analysis. Results revealed the presence of trace elements normally found in plants, such as; K-42, I-124, Cl-38, Na-24, Br-82, and Mn-56. No mercury was detected in the sample specimen analyzed

  8. Fuel element

    International Nuclear Information System (INIS)

    Hirose, Yasuo.

    1982-01-01

    Purpose: To increase the plenum space in a fuel element used for a liquid metal cooled reactor. Constitution: A fuel pellet is secured at one end with an end plug and at the other with a coil spring in a tubular container. A mechanism for fixing the coil spring composed of a tubular unit is mounted by friction with the inner surface of the tubular container. Accordingly, the recoiling force of the coil spring can be retained by fixing mechanism with a small volume, and since a large amount of plenum space can be obtained, the internal pressure rise in the cladding tube can be suppressed even if large quantities of fission products are discharged. (Kamimura, M.)

  9. Metaoptics for Spectral and Spatial Beam Manipulation

    Science.gov (United States)

    Raghu Srimathi, Indumathi

    Laser beam combining and beam shaping are two important areas with applications in optical communications, high power lasers, and atmospheric propagation studies. In this dissertation, metaoptical elements have been developed for spectral and spatial beam shaping, and multiplexing. Beams carrying orbital angular momentum (OAM), referred to as optical vortices, have unique propagation properties. Optical vortex beams carrying different topological charges are orthogonal to each other and have low inter-modal crosstalk which allows for them to be (de)multiplexed. Efficient spatial (de)multiplexing of these beams have been carried out by using diffractive optical geometrical coordinate transformation elements. The spatial beam combining technique shown here is advantageous because the efficiency of the system is not dependent on the number of OAM states being combined. The system is capable of generating coaxially propagating beams in the far-field and the beams generated can either be incoherently or coherently multiplexed with applications in power scaling and dynamic intensity profile manipulations. Spectral beam combining can also be achieved with the coordinate transformation elements. The different wavelengths emitted by fiber sources can be spatially overlapped in the far-field plane and the generated beams are Bessel-Gauss in nature with enhanced depth of focus properties. Unique system responses and beam shapes in the far-field can be realized by controlling amplitude, phase, and polarization at the micro-scale. This has been achieved by spatially varying the structural parameters at the subwavelength scale and is analogous to local modification of material properties. With advancements in fabrication technology, it is possible to control not just the lithographic process, but also the deposition process. In this work, a unique combination of spatial structure variations in conjunction with the conformal coating properties of an atomic layer deposition tool

  10. Onboard spectral imager data processor

    Science.gov (United States)

    Otten, Leonard J.; Meigs, Andrew D.; Franklin, Abraham J.; Sears, Robert D.; Robison, Mark W.; Rafert, J. Bruce; Fronterhouse, Donald C.; Grotbeck, Ronald L.

    1999-10-01

    Previous papers have described the concept behind the MightySat II.1 program, the satellite's Fourier Transform imaging spectrometer's optical design, the design for the spectral imaging payload, and its initial qualification testing. This paper discusses the on board data processing designed to reduce the amount of downloaded data by an order of magnitude and provide a demonstration of a smart spaceborne spectral imaging sensor. Two custom components, a spectral imager interface 6U VME card that moves data at over 30 MByte/sec, and four TI C-40 processors mounted to a second 6U VME and daughter card, are used to adapt the sensor to the spacecraft and provide the necessary high speed processing. A system architecture that offers both on board real time image processing and high-speed post data collection analysis of the spectral data has been developed. In addition to the on board processing of the raw data into a usable spectral data volume, one feature extraction technique has been incorporated. This algorithm operates on the basic interferometric data. The algorithm is integrated within the data compression process to search for uploadable feature descriptions.

  11. Intersection numbers of spectral curves

    CERN Document Server

    Eynard, B.

    2011-01-01

    We compute the symplectic invariants of an arbitrary spectral curve with only 1 branchpoint in terms of integrals of characteristic classes in the moduli space of curves. Our formula associates to any spectral curve, a characteristic class, which is determined by the laplace transform of the spectral curve. This is a hint to the key role of Laplace transform in mirror symmetry. When the spectral curve is y=\\sqrt{x}, the formula gives Kontsevich--Witten intersection numbers, when the spectral curve is chosen to be the Lambert function \\exp{x}=y\\exp{-y}, the formula gives the ELSV formula for Hurwitz numbers, and when one chooses the mirror of C^3 with framing f, i.e. \\exp{-x}=\\exp{-yf}(1-\\exp{-y}), the formula gives the Marino-Vafa formula, i.e. the generating function of Gromov-Witten invariants of C^3. In some sense this formula generalizes ELSV, Marino-Vafa formula, and Mumford formula.

  12. Spectral filtering for plant production

    Energy Technology Data Exchange (ETDEWEB)

    Young, R.E.; McMahon, M.J.; Rajapakse, N.C.; Becoteau, D.R.

    1994-12-31

    Research to date suggests that spectral filtering can be an effective alternative to chemical growth regulators for altering plant development. If properly implemented, it can be nonchemical and environmentally friendly. The aqueous CuSO{sub 4}, and CuCl{sub 2} solutions in channelled plastic panels have been shown to be effective filters, but they can be highly toxic if the solutions contact plants. Some studies suggest that spectral filtration limited to short EOD intervals can also alter plant development. Future research should be directed toward confirmation of the influence of spectral filters and exposure times on a broader range of plant species and cultivars. Efforts should also be made to identify non-noxious alternatives to aqueous copper solutions and/or to incorporate these chemicals permanently into plastic films and panels that can be used in greenhouse construction. It would also be informative to study the impacts of spectral filters on insect and microbal populations in plant growth facilities. The economic impacts of spectral filtering techniques should be assessed for each delivery methodology.

  13. Spectral dimension of quantum geometries

    International Nuclear Information System (INIS)

    Calcagni, Gianluca; Oriti, Daniele; Thürigen, Johannes

    2014-01-01

    The spectral dimension is an indicator of geometry and topology of spacetime and a tool to compare the description of quantum geometry in various approaches to quantum gravity. This is possible because it can be defined not only on smooth geometries but also on discrete (e.g., simplicial) ones. In this paper, we consider the spectral dimension of quantum states of spatial geometry defined on combinatorial complexes endowed with additional algebraic data: the kinematical quantum states of loop quantum gravity (LQG). Preliminarily, the effects of topology and discreteness of classical discrete geometries are studied in a systematic manner. We look for states reproducing the spectral dimension of a classical space in the appropriate regime. We also test the hypothesis that in LQG, as in other approaches, there is a scale dependence of the spectral dimension, which runs from the topological dimension at large scales to a smaller one at short distances. While our results do not give any strong support to this hypothesis, we can however pinpoint when the topological dimension is reproduced by LQG quantum states. Overall, by exploring the interplay of combinatorial, topological and geometrical effects, and by considering various kinds of quantum states such as coherent states and their superpositions, we find that the spectral dimension of discrete quantum geometries is more sensitive to the underlying combinatorial structures than to the details of the additional data associated with them. (paper)

  14. Spectral Imaging of Portolan Charts

    Science.gov (United States)

    France, Fenella G.; Wilson, Meghan A.; Ghez, Anita

    2018-05-01

    Spectral imaging of Portolan Charts, early nautical charts, provided extensive new information about their construction and creation. The origins of the portolan chart style have been a continual source of perplexity to numerous generations of cartographic historians. The spectral imaging system utilized incorporates a 50 megapixel mono-chrome camera with light emitting diode (LED) illumination panels that cover the range from 365 nm to 1050 nm to capture visible and non-visible information. There is little known about how portolan charts evolved, and what influenced their creation. These early nautical charts began as working navigational tools of medieval mariners, initially made in the 1300s in Italy, Portugal and Spain; however the origin and development of the portolan chart remained shrouded in mystery. Questions about these early navigational charts included whether colorants were commensurate with the time period and geographical location, and if different, did that give insight into trade routes, or possible later additions to the charts? For example; spectral data showed the red pigment on both the 1320 portolan chart and the 1565 Galapagos Islands matched vermillion, an opaque red pigment used since antiquity. The construction of these charts was also of great interest. Spectral imaging with a range of illumination modes revealed the presence of a "hidden circle" often referred to in relation to their construction. This paper will present in-depth analysis of how spectral imaging of the Portolans revealed similarities and differences, new hidden information and shed new light on construction and composition.

  15. Diagnostic Accuracy of the Volume Rendering Images of Multi-Detector CT for the Detection of Lumbar Transverse Process Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yun Hak; Chun, Tong Jin [Dept. of Radiology, Eulji University Hospital, Daejeon (Korea, Republic of)

    2012-01-15

    To compare the accuracy of three-dimensional computed tomographic (3D CT) volume rendering techniques with axial images of multi-detector row computed tomography to identify lumbar transverse process (LTP) fractures in trauma patients. We retrospectively evaluated 42 patients with back pain as a result of blunt trauma between January and June of 2010. Two radiologists examined the 3D CT volume rendering images independently. The confirmation of a LTP fracture was based on the consensus of the axial images by the two radiologists. The results of 3D CT volume rendering images were compared with the axial images and the diagnostic powers (sensitivity, specificity, and accuracy) were calculated. Seven of the 42 patients had twenty five lumbar transverse process fractures. The diagnostic power of the 3D CT volume rendering technique is as accurate as axial images. Reader 1, sensitivity 96%, specificity 100%, accuracy 99.9%; and Reader 2 sensitivity 100%, specificity 99.8%, accuracy 99.8%. The accordance of the two radiologists was 99.8%. 3D CT volume rendering images can alternate axial images to detect lumbar transverse process fractures with good image quality.

  16. Near-infrared spectral imaging Michelson interferometer for astronomical applications

    Science.gov (United States)

    Wells, C. W.; Potter, A. E.; Morgan, T. H.

    1980-01-01

    The design and operation of an imaging Michelson interferometer-spectrometer used for near-infrared (0.8 micron to 2.5 microns) spectral imaging are reported. The system employs a rapid scan interferometer modified for stable low resolution (250/cm) performance and a 42 element PbS linear detector array. A microcomputer system is described which provides data acquisition, coadding, and Fourier transformation for near real-time presentation of the spectra of all 42 scene elements. The electronic and mechanical designs are discussed and telescope performance data presented.

  17. Examination of Spectral Transformations on Spectral Mixture Analysis

    Science.gov (United States)

    Deng, Y.; Wu, C.

    2018-04-01

    While many spectral transformation techniques have been applied on spectral mixture analysis (SMA), few study examined their necessity and applicability. This paper focused on exploring the difference between spectrally transformed schemes and untransformed scheme to find out which transformed scheme performed better in SMA. In particular, nine spectrally transformed schemes as well as untransformed scheme were examined in two study areas. Each transformed scheme was tested 100 times using different endmember classes' spectra under the endmember model of vegetation- high albedo impervious surface area-low albedo impervious surface area-soil (V-ISAh-ISAl-S). Performance of each scheme was assessed based on mean absolute error (MAE). Statistical analysis technique, Paired-Samples T test, was applied to test the significance of mean MAEs' difference between transformed and untransformed schemes. Results demonstrated that only NSMA could exceed the untransformed scheme in all study areas. Some transformed schemes showed unstable performance since they outperformed the untransformed scheme in one area but weakened the SMA result in another region.

  18. Berlin Reflectance Spectral Library (BRSL)

    Science.gov (United States)

    Henckel, D.; Arnold, G.; Kappel, D.; Moroz, L. V.; Markus, K.

    2017-09-01

    The Berlin Reflectance Spectral Library (BRSL) provides a collection of reflectance spectra between 0.3 and 17 µm. It was originally dedicated to support space missions to small solar system bodies. Meanwhile the library includes selections of biconical reflectance spectra for spectral data analysis of other planetary bodies as well. The library provides reference spectra of well-characterized terrestrial analogue materials and meteorites for interpretation of remote sensing reflectance spectra of planetary surfaces. We introduce the BRSL, summarize the data available, and access to use them for further relevant applications.

  19. Spectral ellipsometry of nanodiamond composite

    International Nuclear Information System (INIS)

    Yastrebov, S.G.; Ivanov-Omskij, V.I.; Gordeev, S.K.; Garriga, M.; Alonso, I.A.

    2006-01-01

    Methods of spectral ellipsometry were applied for analysis of optical properties of nanodiamond based composite in spectral region 1.4-5 eV. The nanocomposite was synthesized by molding of ultradispersed nanodiamond powder in the course of heterogeneous chemical reaction of decomposition of methane, forming pyrocarbon interconnecting nanodiamond grains. The energy of σ + π plasmon of pyrocarbon component of nanodiamond composite was restored which proves to be ∼ 24 eV; using this value, an estimation was done of pyrocarbon matrix density, which occurs to be 2 g/cm 3 [ru

  20. Spectral determination of individual rare earths in different classes of inorganic compounds

    International Nuclear Information System (INIS)

    Karpenko, L.I.; Fadeeva, L.A.; Shevchenko, L.D.

    1979-01-01

    The conditions are found allowing to analyze various inorganic compounds for rare-earth elements without separation from non-rare-earth components. The influence of the plasma composition on the intensity of spectral lines of rare-earth elements is studied. The relative intensity of homologous spectral lines of various rare-earth elements remains constant regardless of the plasma composition. The conditions are found for the determination of individual rare-earth elements acting as both alloying additives (Csub(n) -- n x 10 -1 -n x 10 -3 %), and basic components (up to tens of per cent) in different classes of inorganic compounds of 1-7 elements. The general method is developed for the determination of individual rare-earth elements in mixtures of oxides of rare-earth elements, complex fluorides of rare-earth elements and elements of group 2, gallates, borates, germanates, vanadates of rare-earth elements and aluminium; zirconates-titanates of lead and barium, containing modifying additives of rare-earth elements, complex chalcogenides of rare-earth elements and elements of group 5