Log in

Relevant bibliographies by topics / Spherical parameterization / Journal articles

To see the other types of publications on this topic, follow the link: Spherical parameterization.

Journal articles on the topic 'Spherical parameterization'

Author: Grafiati

Published: 4 June 2021

Last updated: 7 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Spherical parameterization.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Friedel, Ilja, Peter Schröder, and Mathieu Desbrun. "Unconstrained Spherical Parameterization." Journal of Graphics Tools 12, no. 1 (January 2007): 17–26. http://dx.doi.org/10.1080/2151237x.2007.10129230.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Dupuy, Jonathan, Eric Heitz, and Laurent Belcour. "A spherical cap preserving parameterization for spherical distributions." ACM Transactions on Graphics 36, no. 4 (July 20, 2017): 1–12. http://dx.doi.org/10.1145/3072959.3073694.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Wu, Yong, Yuanjun He, and Haishan Tian. "Relaxation of spherical parameterization meshes." Visual Computer 21, no. 11 (July 22, 2005): 897–904. http://dx.doi.org/10.1007/s00371-005-0301-7.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Li, Li, David Zhang, Zhigeng Pan, Jiaoying Shi, Kun Zhou, and Kai Ye. "Watermarking 3D mesh by spherical parameterization." Computers & Graphics 28, no. 6 (December 2004): 981–89. http://dx.doi.org/10.1016/j.cag.2004.08.002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Sheffer, A., C. Gotsman, and N. Dyn. "Robust Spherical Parameterization of Triangular Meshes." Computing 72, no. 1-2 (April 1, 2004): 185–93. http://dx.doi.org/10.1007/s00607-004-0056-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Räisänen, P., A. Kokhanovsky, G. Guyot, O. Jourdan, and T. Nousiainen. "Parameterization of single-scattering properties of snow." Cryosphere 9, no. 3 (June 23, 2015): 1277–301. http://dx.doi.org/10.5194/tc-9-1277-2015.

Full text

Abstract:

Abstract. Snow consists of non-spherical grains of various shapes and sizes. Still, in many radiative transfer applications, single-scattering properties of snow have been based on the assumption of spherical grains. More recently, second-generation Koch fractals have been employed. While they produce a relatively flat phase function typical of deformed non-spherical particles, this is still a rather ad hoc choice. Here, angular scattering measurements for blowing snow conducted during the CLimate IMpacts of Short-Lived pollutants In the Polar region (CLIMSLIP) campaign at Ny Ålesund, Svalbard, are used to construct a reference phase function for snow. Based on this phase function, an optimized habit combination (OHC) consisting of severely rough (SR) droxtals, aggregates of SR plates and strongly distorted Koch fractals is selected. The single-scattering properties of snow are then computed for the OHC as a function of wavelength λ and snow grain volume-to-projected area equivalent radius rvp. Parameterization equations are developed for λ = 0.199–2.7 μm and rvp = 10–2000 μm, which express the single-scattering co-albedo β, the asymmetry parameter g and the phase function P11 as functions of the size parameter and the real and imaginary parts of the refractive index. The parameterizations are analytic and simple to use in radiative transfer models. Compared to the reference values computed for the OHC, the accuracy of the parameterization is very high for β and g. This is also true for the phase function parameterization, except for strongly absorbing cases (β > 0.3). Finally, we consider snow albedo and reflected radiances for the suggested snow optics parameterization, making comparisons to spheres and distorted Koch fractals.

APA, Harvard, Vancouver, ISO, and other styles

7

Räisänen, P., A. Kokhanovsky, G. Guyot, O. Jourdan, and T. Nousiainen. "Parameterization of single-scattering properties of snow." Cryosphere Discussions 9, no. 1 (February 13, 2015): 873–926. http://dx.doi.org/10.5194/tcd-9-873-2015.

Full text

Abstract:

Abstract. Snow consists of non-spherical grains of various shapes and sizes. Still, in many radiative transfer applications, single-scattering properties of snow have been based on the assumption of spherical grains. More recently, second-generation Koch fractals have been employed. While they produce a relatively flat phase function typical of deformed non-spherical particles, this is still a rather ad-hoc choice. Here, angular scattering measurements for blowing snow conducted during the CLimate IMpacts of Short-Lived pollutants In the Polar region (CLIMSLIP) campaign at Ny Ålesund, Svalbard, are used to construct a reference phase function for snow. Based on this phase function, an optimized habit combination (OHC) consisting of severely rough (SR) droxtals, aggregates of SR plates and strongly distorted Koch fractals is selected. The single-scattering properties of snow are then computed for the OHC as a function of wavelength λ and snow grain volume-to-projected area equivalent radius rvp. Parameterization equations are developed for λ = 0.199–2.7 μm and rvp = 10–2000 μm, which express the single-scattering co-albedo β, the asymmetry parameter g and the phase function P11 as functions of the size parameter and the real and imaginary parts of the refractive index. The parameterizations are analytic and simple to use in radiative transfer models. Compared to the reference values computed for the OHC, the accuracy of the parameterization is very high for β and g. This is also true for the phase function parameterization, except for strongly absorbing cases (β > 0.3). Finally, we consider snow albedo and reflected radiances for the suggested snow optics parameterization, making comparisons to spheres and distorted Koch fractals.

APA, Harvard, Vancouver, ISO, and other styles

8

ZHANG, Jielin, Zhao WANG, and Zhongxuan LUO. "Spherical parameterization based on planar ARAP+ method." SCIENTIA SINICA Informationis 47, no. 4 (February 22, 2017): 428–41. http://dx.doi.org/10.1360/n112016-00172.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Nadeem, Saad, Zhengyu Su, Wei Zeng, Arie Kaufman, and Xianfeng Gu. "Spherical Parameterization Balancing Angle and Area Distortions." IEEE Transactions on Visualization and Computer Graphics 23, no. 6 (June 1, 2017): 1663–76. http://dx.doi.org/10.1109/tvcg.2016.2542073.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Gotsman, Craig, Xianfeng Gu, and Alla Sheffer. "Fundamentals of spherical parameterization for 3D meshes." ACM Transactions on Graphics 22, no. 3 (July 2003): 358–63. http://dx.doi.org/10.1145/882262.882276.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Li, J., and Kiyotaka Shibata. "On the Effective Solar Pathlength." Journal of the Atmospheric Sciences 63, no. 4 (April 1, 2006): 1365–73. http://dx.doi.org/10.1175/jas3682.1.

Full text

Abstract:

Abstract The effects of atmospheric spherical curvature and refraction and their impact on radiative transfer have been studied. It is shown that formulas employed in GCMs for atmospheric curvature and refraction underestimate the effect of effective solar pathlength. A new parameterization is therefore proposed. It is emphasized that the atmospheric curvature effect on radiative transfer is a localized problem with height dependence. A method corresponding to the local effective pathlength factor is proposed. This rigorous scheme enables variations in both the pathlength and the gaseous amount along a solar direct beam to be accurately evaluated in the radiative transfer process. The results of the rigorous scheme can be used as the benchmark to the proposed parameterizations for the effective pathlength factor. It is found that the new parameterization proposed in this note has better results in flux and heating rates when compared to other parameterizations.

APA, Harvard, Vancouver, ISO, and other styles

12

Li, Guangxu, Hyoungseop Kim, Joo Kooi Tan, and Seiji Ishikawa. "A Parameterization Based Correspondence Method for PDM Building." Journal of Advanced Computational Intelligence and Intelligent Informatics 17, no. 1 (January 20, 2013): 18–26. http://dx.doi.org/10.20965/jaciii.2013.p0018.

Full text

Abstract:

Place-march of corresponding landmarks is one of the major factors influencing 3D Points Distribution Model (PDM) quality. In this study, we propose a semi-automatic correspondence method based on surface parameterization theory. All the training sets are mapped into a spherical domain previously. The rotation transformation of training samples is regarded as spherical rotation of their maps. We solve it by comparing the density distribution of surface map of training sample with respect to the reference model. Simultaneously, the corresponding landmarks across the whole training set are marketed depending on the spherical coordinates on parameter domain. In this paper, we also compared the corresponding results with two constraint conditions of spherical conformal mapping: 3 datum points constrain and zero-mass constrain. Experimental results are given for left lung training sets of 3D shapes. The mean result with the 3 datum points constraint and the zero mass-center constraint was 21.65 mm and 20.19 mm respectively.

APA, Harvard, Vancouver, ISO, and other styles

13

Bruvoll, Solveig, and Martin Reimers. "Spherical surface parameterization for perspective shape from shading." Pattern Recognition Letters 33, no. 1 (January 2012): 33–40. http://dx.doi.org/10.1016/j.patrec.2011.09.026.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Wang, Zheng, and F. A. Dahlen. "Spherical-spline parameterization of three-dimensional earth models." Geophysical Research Letters 22, no. 22 (November 15, 1995): 3099–102. http://dx.doi.org/10.1029/95gl03080.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Wang, Zhao, Zhongxuan Luo, Jielin Zhang, and Emil Saucan. "A novel local/global approach to spherical parameterization." Journal of Computational and Applied Mathematics 329 (February 2018): 294–306. http://dx.doi.org/10.1016/j.cam.2017.05.011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Chen, X., H. He, G. Zou, X. Zhang, X. Gu, and J. Hua. "Ricci flow-based spherical parameterization and surface registration." Computer Vision and Image Understanding 117, no. 9 (September 2013): 1107–18. http://dx.doi.org/10.1016/j.cviu.2013.02.010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Jin, Han-Gyul, and Jong-Jin Baik. "A New Parameterization of the Accretion of Cloud Water by Snow and Its Evaluation through Simulations of Mesoscale Convective Systems." Journal of the Atmospheric Sciences 77, no. 8 (July 29, 2020): 2885–903. http://dx.doi.org/10.1175/jas-d-19-0326.1.

Full text

Abstract:

Abstract A new parameterization of the accretion of cloud water by snow for use in bulk microphysics schemes is derived as an analytic approximation of the stochastic collection equation (SCE), where the theoretical collision efficiency for individual snowflake–cloud droplet pairs is applied. The snowflake shape is assumed to be nonspherical with the mass–size and area–size relations suggested by an observational study. The performance of the new parameterization is compared to two parameterizations based on the continuous collection equation, one with the spherical shape assumption for snowflakes (SPH-CON), and the other with the nonspherical shape assumption employed in the new parameterization (NSP-CON). In box model simulations, only the new parameterization reproduces a relatively slow decrease in the cloud droplet number concentration, which is predicted by the direct SCE solver. This results from considering the preferential collection of cloud droplets depending on their sizes in the new parameterization based on the SCE. In idealized squall-line simulations using a cloud-resolving model, the new parameterization predicts heavier precipitation in the convective core region compared to SPH-CON, and a broader area of the trailing stratiform rain compared to NSP-CON due to the horizontal advection of greater amount of snow in the upper layer. In the real-case simulations of a line-shaped mesoscale convective system that passed over the central Korean Peninsula, the new parameterization predicts higher frequencies of light precipitation rates and lower frequencies of heavy precipitation rates. The relatively large amount of upper-level snow in the new parameterization contributes to a broadening of the area with significant snow water path.

APA, Harvard, Vancouver, ISO, and other styles

18

Wang, Jian Guo, Qun E, Ke Ming Yao, and Xin Long Wan. "Empirical Mode Decomposition on Geometry Signal Based Spherical Parameterization." Advanced Materials Research 998-999 (July 2014): 860–63. http://dx.doi.org/10.4028/www.scientific.net/amr.998-999.860.

Full text

Abstract:

A novel method based onEmpirical Mode Decomposition(EMD) is approached to process the geometry signal. The main idea is to decompose the signal into some different detail components called Intrinsic Mode Function (IMF). The key steps are as follows: First, the signal is spherical parameterization; Second it is transformed into the plane signal and sampled regularly; Third, the translated signal is processed as an image using Bid-Empirical Mode Decomposition, getting several image IMFs; Finally, invert mapping these IMFs to geometry signal and getting the geometry signal’s IMFs.We demonstrate the power of the algorithms through a number of application examples including de-noising and enhancement.

APA, Harvard, Vancouver, ISO, and other styles

19

Hu, Jian Ping, and Qi Xie. "Mesh Denoising Based on Spherical Wavelets in Reverse Engineering." Applied Mechanics and Materials 232 (November 2012): 904–7. http://dx.doi.org/10.4028/www.scientific.net/amm.232.904.

Full text

Abstract:

This paper presents an approach for removing noises of 3D meshes using spherical wavelets. An input 3D mesh is firstly transformed into a spherical signal by a fast low distortion spherical parameterization. This spherical signal is then sampled regularly on the sphere and transformed into the wavelet domain where noises of 3D meshes can be removed easily. Experiments are taken with some typical 3D meshes, which reveals that our method can obtain good results.

APA, Harvard, Vancouver, ISO, and other styles

20

Wang, Zheng, Jeroen Tromp, and Göran Ekström. "Global and regional surface-wave inversions: A spherical-spline parameterization." Geophysical Research Letters 25, no. 2 (January 15, 1998): 207–10. http://dx.doi.org/10.1029/97gl03634.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Choi, Gary Pui-Tung, Kin Tat Ho, and Lok Ming Lui. "Spherical Conformal Parameterization of Genus-0 Point Clouds for Meshing." SIAM Journal on Imaging Sciences 9, no. 4 (January 2016): 1582–618. http://dx.doi.org/10.1137/15m1037561.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Athanasiadis, Theodoros, Ioannis Fudos, Christophoros Nikou, and Vasiliki Stamati. "Feature-based 3D morphing based on geometrically constrained spherical parameterization." Computer Aided Geometric Design 29, no. 1 (January 2012): 2–17. http://dx.doi.org/10.1016/j.cagd.2011.09.004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Ma, Wan-Chun, Chun-Tse Hsiao, Ken-Yi Lee, Yung-Yu Chuang, and Bing-Yu Chen. "Real-time triple product relighting using spherical local-frame parameterization." Visual Computer 22, no. 9-11 (August 25, 2006): 682–92. http://dx.doi.org/10.1007/s00371-006-0064-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Lee, Tong-Yee, Chih-Yuan Yao, Hung-Kuo Chu, Ming-Jen Tai, and Cheng-Chieh Chen. "Generating genus-n-to-m mesh morphing using spherical parameterization." Computer Animation and Virtual Worlds 17, no. 3-4 (2006): 433–43. http://dx.doi.org/10.1002/cav.146.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Wu, Xing Hui, and Zhi Xiu Hao. "Evaluation of Spherical Parameterization Methods for Three-Dimensional Reconstruction of Medical Images." Applied Mechanics and Materials 365-366 (August 2013): 1342–49. http://dx.doi.org/10.4028/www.scientific.net/amm.365-366.1342.

Full text

Abstract:

The spherical parameterization is important for the correspondence problem that is a major part of statistical shape modelling for the reconstruction of patient-specific 3D models from medical images. In this paper, we present comparative studies of five common spherical mapping methods applied to the femur and tibia models: the Issenburg et al. method, the Alexa method, the Saba et al. method, the Praun et al. method and the Shen et al. method. These methods are evaluated using three sets of measures: distortion property, geometric error and distance to standard landmarks. Results show that the Praun et al. method performs better than other methods while the Shen et al. method can be regarded as the most reliable one for providing an acceptable correspondence result. We suggest that the area preserving property can be used as a sufficient condition while the angle preserving property is not important when choosing a spherical mapping method for correspondence application.

APA, Harvard, Vancouver, ISO, and other styles

26

Hu, Jian-ping, Xiu-ping Liu, Zhi-xun Su, Xi-quan Shi, and Feng-shan Liu. "A spherical parameterization approach based on symmetry analysis of triangular meshes." Journal of Zhejiang University-SCIENCE A 10, no. 7 (July 2009): 1009–17. http://dx.doi.org/10.1631/jzus.a0820728.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Khairy, Khaled, and Jonathon Howard. "Minimum-energy vesicle and cell shapes calculated using spherical harmonics parameterization." Soft Matter 7, no. 5 (2011): 2138. http://dx.doi.org/10.1039/c0sm01193b.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Nielson, Gregory M., Li-Yan Zhang, Kun Lee, and Adam Huang. "Spherical Parameterization of Marching Cubes IsoSurfaces Based upon Nearest Neighbor Coordinates." Journal of Computer Science and Technology 24, no. 1 (January 2009): 30–38. http://dx.doi.org/10.1007/s11390-009-9201-z.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

McCarthy, J. M. "The Opposite Pole Quadrilateral as a Compatibility Linkage for Parameterizing the Center Point Curve." Journal of Mechanical Design 115, no. 2 (June 1, 1993): 332–36. http://dx.doi.org/10.1115/1.2919196.

Full text

Abstract:

In planar four-position kinematics, the centers of circles containing four positions of a point in a moving rigid body form the center point curve. This curve can be parameterized by analyzing a “compatibility linkage” obtained from a complex number formulation of the four-position problem. In this paper, we present another derivation of the center point curve using a special form of dual quaternions and the fact that it is identical to the pole curve. The defining properties of the pole curve lead to a parameterization by kinematic analysis of the opposite pole quadrilateral as a four-bar linkage. Thus the opposite pole quadrilateral becomes the compatibility linkage. This derivation generalizes to provide parameterizations for the center point cone of spherical kinematics and the central axis congruence of spatial kinematic theory.

APA, Harvard, Vancouver, ISO, and other styles

30

Nguyen, Kim-Doang. "On the adaptive control of spherical actuators." Transactions of the Institute of Measurement and Control 41, no. 3 (May 23, 2018): 816–27. http://dx.doi.org/10.1177/0142331218771144.

Full text

Abstract:

This paper addresses the control problem of multi-degree-of-freedom actuators with uncertain torque models and unmodelled system parameters, such as the rotor’s moments of inertia. The control scheme relies on (i) the parameterization of the system nonlinearity in terms of two regression functions and the unknown parameters, and (ii) a control structure with filtered input torque and projection-based adaptation laws. The input–output mapping analysis rigorously shows that the proposed controller maintains the bounded deviation of the control system from a stable, non-adaptive reference system. The size of the deviation is inversely proportional to the filter bandwidth. Simulations using a standard model of spherical motors illustrate the tracking performance of the controlled rotor’s orientations.

APA, Harvard, Vancouver, ISO, and other styles

31

Peng, Chao, and Sabin Timalsena. "Fast mapping and morphing for genus-zero meshes with cross spherical parameterization." Computers & Graphics 59 (October 2016): 107–18. http://dx.doi.org/10.1016/j.cag.2016.06.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Lu, Xiao Yang, Xiao Wei Zhao, Li Li Huang, Qing Wang, and Chao Wang. "Shape Optimizing Design of Kiewiti Spherical Reticulated Shell." Advanced Materials Research 424-425 (January 2012): 324–29. http://dx.doi.org/10.4028/www.scientific.net/amr.424-425.324.

Full text

Abstract:

With gross weight minimum of reticulated shell (including elements and nodes) as the objective function, with cross section size of elements, the volume of spherical nodes and shell shape parameter (kn, nx) as design variables, a two-level shape optimizing mathematical model of spherical reticulated shell, which is based on discrete variables, is established, and the corresponding optimizing design programmes are made. Model establishing with modeling macro program of spherical reticulated shell parameterization, using ANSYS software for the structure force analysis, this programme has the characteristics of high optimizing efficiency with multiple designing schemes, and high analyzing and computing accuracy. Some practical and valuable conclusions are reached by the analysis and comparisons of optimizing design results of 42 Kiewit spherical reticulated shells with six kinds of span and seven kinds of rise-span ratios

APA, Harvard, Vancouver, ISO, and other styles

33

McCarthy, J. M. "The Image Curve of the Coupler of a Special Spherical Four Bar Linkage." Journal of Mechanisms, Transmissions, and Automation in Design 110, no. 3 (September 1, 1988): 276–80. http://dx.doi.org/10.1115/1.3267458.

Full text

Abstract:

This paper uses a kinematic mapping of spherical motion to derive an image curve which represents the coupler motion of a doubly folding spherical four bar linkage. The image curve of this linkage, the so called “kite” linkage, can be parameterized by rational functions. This parameterization is presented as well as formulas which allow the computation of its curvature and torsion at any point. These formulas provide a link between the global properties of the coupler motion as represented by the image curve itself and its instantaneous properties given by the curvature and torsion functions.

APA, Harvard, Vancouver, ISO, and other styles

34

Wu Linhui, 武林会, 赵会娟 Zhao Huijuan, 易茜 Yi Xi, 张伟 Zhang Wei, and 高峰 Gao Feng. "Pilot Investigation into Shape-Based Diffuse Optical Tomography Methodology with Spherical Harmonics Parameterization." Acta Optica Sinica 33, no. 6 (2013): 0617002. http://dx.doi.org/10.3788/aos201333.0617002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Wang, Daifa, Jin He, Huiting Qiao, Xiaolei Song, Yubo Fan, and Deyu Li. "High-Performance Fluorescence Molecular Tomography through Shape-Based Reconstruction Using Spherical Harmonics Parameterization." PLoS ONE 9, no. 4 (April 14, 2014): e94317. http://dx.doi.org/10.1371/journal.pone.0094317.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Furutachi, Naoya, Futoshi Minato, and Osamu Iwamoto. "Phenomenological level density model with hybrid parameterization of deformed and spherical state densities." Journal of Nuclear Science and Technology 56, no. 5 (March 17, 2019): 412–24. http://dx.doi.org/10.1080/00223131.2019.1588801.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Choi, Pui Tung, Ka Chun Lam, and Lok Ming Lui. "FLASH: Fast Landmark Aligned Spherical Harmonic Parameterization for Genus-0 Closed Brain Surfaces." SIAM Journal on Imaging Sciences 8, no. 1 (January 2015): 67–94. http://dx.doi.org/10.1137/130950008.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Bastl, Bohumír, Bert Jüttler, Miroslav Lávička, Josef Schicho, and Zbyněk Šír. "Spherical quadratic Bézier triangles with chord length parameterization and tripolar coordinates in space." Computer Aided Geometric Design 28, no. 2 (February 2011): 127–34. http://dx.doi.org/10.1016/j.cagd.2010.11.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Osorio, Alejandro I. Flores, Nielce M. Lobo da Costa, Dennis A. Espejo Peña, and Lenin R. Cabracancha Montesinos. "Modelamiento de Superficies en Coordenadas Esféricas a Través de GeoGebra." Jornal Internacional de Estudos em Educação Matemática 13, no. 1 (June 22, 2020): 02–05. http://dx.doi.org/10.17921/2176-5634.2020v13n1p02-05.

Full text

Abstract:

Este artículo tiene como objetivo presentar una herramienta que permita ayudar la enseñanza y el aprendizaje de graficar y describir superficies en coordenadas esféricas, a través del software libre GeoGebra, para lo cual se va representar superficies convencionales y no convencionales, así como sólidos que están limitados por un número finito de superficies por medio de parametrizaciones basadas en coordenadas esféricas y luego presentarlas en la vista gráfica 3D de GeoGebra usando el comando Superficie, de esta forma se tiene una inmejorable visualizar, percepción, manipulación y comprensión del esbozo de superficies en el espacio en un ambiente dinámico y amigable. Finalizamos con un caso de aplicación de modelado del planetario más grande del mundo aplicando superficies paramétricas basadas en las coordenadas esféricas. Palabras-clave: Modelamiento. Superficies. Parametrización. Coordenadas Esféricas. GeoGebra. Abstract This article aims to present a tool that aids the teaching and learning of graphing and describing surfaces in spherical coordinates, through the free GeoGebra software, for which specific and non-specific surfaces will be represented, as well as solids that are limited by a finite number of surfaces by means of parameterizations based on spherical coordinates and then present them in the GeoGebra 3D graphic view using the Surface command, in this way you have an unbeatable visualization, perception, manipulation and understanding of the outline of surfaces in the space in a dynamic and friendly environment. We conclude with a case of modeling application of the largest planetarium in the world applying parametric surfaces based on spherical coordinates Keywords: Modeling. Surfaces. Parameterization. Spherical Coordinates. GeoGebra.

APA, Harvard, Vancouver, ISO, and other styles

40

Benediktovich, Andrey, Ilya Feranchuk, and Alex Ulyanenkov. "Calculation of X-Ray Stress Factors Using Vector Parameterization and Irreducible Representations for SO(3) Group." Materials Science Forum 681 (March 2011): 387–92. http://dx.doi.org/10.4028/www.scientific.net/msf.681.387.

Full text

Abstract:

In the presence of texture, the concept of X-ray elastic constants as well as Sin2ψ law is inapplicable and the X-ray stress factors (XSF) connecting average strain and stress have to be used [1-2]. The SO(3) vector parameterization with smart composition law [3-4] proved to be a powerful tool for handling transformations between reference systems used in XSF calculation. Decomposition of the 4-th rank elastic constant tensor on the SO(3) irreducible representations (IR) allows one to highlight the symmetry properties and to separate isotropic and anisotropic parts. Joint use of the vector parameterization and IR decomposition enables to obtain transparent analytical expressions for XSF in case of textures described by preferred spherical/fiber components.

APA, Harvard, Vancouver, ISO, and other styles

41

Hasha, Alexander, Oliver Bühler, and John Scinocca. "Gravity Wave Refraction by Three-Dimensionally Varying Winds and the Global Transport of Angular Momentum." Journal of the Atmospheric Sciences 65, no. 9 (September 1, 2008): 2892–906. http://dx.doi.org/10.1175/2007jas2561.1.

Full text

Abstract:

Abstract Operational gravity wave parameterization schemes in GCMs are columnar; that is, they are based on a ray-tracing model for gravity wave propagation that neglects horizontal propagation as well as refraction by horizontally inhomogeneous basic flows. Despite the enormous conceptual and numerical simplifications that these approximations provide, it has never been clearly established whether horizontal propagation and refraction are indeed negligible for atmospheric climate dynamics. In this study, a three-dimensional ray-tracing scheme for internal gravity waves that allows wave refraction and horizontal propagation in spherical geometry is formulated. Various issues to do with three-dimensional wave dynamics and wave–mean interactions are discussed, and then the scheme is applied to offline computations using GCM data and launch spectra provided by an operational columnar gravity wave parameterization scheme for topographic waves. This allows for side-by-side testing and evaluation of momentum fluxes in the new scheme against those of the parameterization scheme. In particular, the wave-induced vertical flux of angular momentum is computed and compared with the predictions of the columnar parameterization scheme. Consistent with a scaling argument, significant changes in the angular momentum flux due to three-dimensional refraction and horizontal propagation are confined to waves near the inertial frequency.

APA, Harvard, Vancouver, ISO, and other styles

42

Choi, Gary Pui-Tung, Mandy Hiu-Ying Man, and Lok Ming Lui. "Fast spherical quasiconformal parameterization of genus-$0$ closed surfaces with application to adaptive remeshing." Geometry, Imaging and Computing 3, no. 1-2 (2016): 1–29. http://dx.doi.org/10.4310/gic.2016.v3.n1.a1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Laga, Hamid, Hiroki Takahashi, and Masayuki Nakajima. "Spherical parameterization and geometry image-based 3D shape similarity estimation (CGS 2004 special issue)." Visual Computer 22, no. 5 (April 21, 2006): 324–31. http://dx.doi.org/10.1007/s00371-006-0010-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Mikucki, Michael, and Yongcheng Zhou. "Fast Simulation of Lipid Vesicle Deformation Using Spherical Harmonic Approximation." Communications in Computational Physics 21, no. 1 (December 5, 2016): 40–64. http://dx.doi.org/10.4208/cicp.oa-2015-0029.

Full text

Abstract:

AbstractLipid vesicles appear ubiquitously in biological systems. Understanding how the mechanical and intermolecular interactions deform vesicle membranes is a fundamental question in biophysics. In this article we develop a fast algorithm to compute the surface configurations of lipid vesicles by introducing surface harmonic functions to approximate themembrane surface. This parameterization allows an analytical computation of the membrane curvature energy and its gradient for the efficient minimization of the curvature energy using a nonlinear conjugate gradient method. Our approach drastically reduces the degrees of freedom for approximating the membrane surfaces compared to the previously developed finite element and finite difference methods. Vesicle deformations with a reduced volume larger than 0.65 can be well approximated by using as small as 49 surface harmonic functions. The method thus has a great potential to reduce the computational expense of tracking multiple vesicles which deform for their interaction with external fields.

APA, Harvard, Vancouver, ISO, and other styles

45

Zhang, Feng, and Jiangnan Li. "Doubling–Adding Method for Delta-Four-Stream Spherical Harmonic Expansion Approximation in Radiative Transfer Parameterization." Journal of the Atmospheric Sciences 70, no. 10 (October 1, 2013): 3084–101. http://dx.doi.org/10.1175/jas-d-12-0334.1.

Full text

Abstract:

Abstract Though the single-layer solutions have been found for the δ-four-stream spherical harmonic expansion method (SHM) in radiative transfer, there is lack of a corresponding doubling–adding method (4SDA), which enables the calculation of radiative transfer through a vertically inhomogeneous atmosphere with multilayers. The doubling–adding method is based on Chandrasekhar's invariance principle, which was originally developed for discrete ordinates approximation. It is shown that the invariance principle can also be applied to SHM and δ-four-stream spherical harmonic expansion doubling–adding method (δ-4SDA) is proposed in this paper. The δ-4SDA method has been systematically compared to the δ-Eddington doubling–adding method (δ-2SDA), the δ-two-stream discrete ordinates doubling–adding method (δ-2DDA), and δ-four-stream discrete ordinates doubling–adding method (δ-4DDA). By applying δ-4SDA to a realistic atmospheric profile with gaseous transmission considered, it is found that the accuracy of δ-4SDA is superior to δ-2SDA or δ-2DDA, especially for the cloudy/aerosol conditions. It is shown that the relative errors of δ-4SDA are generally less than 1% in both heating rate and flux, while the relative errors of both δ-2SDA and δ-2DDA can be over 6%. Though δ-4DDA is slightly more accurate than δ-4SDA in heating rates, both of them are accurate enough to obtain the cloud-top solar heating. Here δ-4SDA is superior to δ-4DDA in computational efficiency. It is found that the error of aerosol radiative forcing can be up to 3 W m−2 by using δ-2SDA at the top of the atmosphere (TOA); such error is substantially reduced by applying δ-4SDA. In view of the overall accuracy and computational efficiency, δ-4SDA is suitable for application in climate models.

APA, Harvard, Vancouver, ISO, and other styles

46

Wu, Kun, Feng Zhang, Jinzhong Min, Qiu-Run Yu, Xin-Yue Wang, and Leiming Ma. "Adding method of delta-four-stream spherical harmonic expansion approximation for infrared radiative transfer parameterization." Infrared Physics & Technology 78 (September 2016): 254–62. http://dx.doi.org/10.1016/j.infrared.2016.08.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Afroun, Mohamed, Antoine Dequidt, and Laurent Vermeiren. "Revisiting the inverse dynamics of the Gough–Stewart platform manipulator with special emphasis on universal–prismatic–spherical leg and internal singularity." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 10 (January 17, 2012): 2422–39. http://dx.doi.org/10.1177/0954406211434485.

Full text

Abstract:

This article discusses the dynamic modeling for control of Gough–Stewart platform manipulator with special emphasis on universal–prismatic–spherical leg kinematics. Inverse dynamic model of these six degrees of freedom parallel manipulator robots is reviewed, while complete dynamics with true kinematics of universal–prismatic–spherical legs is compared with several models found in the literature. Most existing models have not taken into account some of the legs kinematical effects, namely the legs angular velocity around their axes and the internal singularities due to passive joints; some other used a simplified parameterization to describe the leg kinematics. Furthermore, some kinetic assumption can be used to reduce the computational burden. This article shows the effect of all these simplifications on the driving forces by simulating the different dynamic models for a commercial manipulator and for different sets of geometric and dynamic parameters of manipulator.

APA, Harvard, Vancouver, ISO, and other styles

48

RAHI, SAHAND JAMAL, and KIM SHARP. "MAPPING COMPLICATED SURFACES ONTO A SPHERE." International Journal of Computational Geometry & Applications 17, no. 04 (August 2007): 305–29. http://dx.doi.org/10.1142/s0218195907002355.

Full text

Abstract:

A method for mapping a closed, triangulated surface of genus 0 onto the unit sphere was developed using a parameterization based on spherical coordinates analogous to latitude and longitude combined with Mercator scaling. The algorithm was tested on 77 protein and DNA surfaces and produce correct (bijective) mappings. The mappings produce relatively uniform distortion, as judged by angular criteria, and by distribution of octant areas, thus facilitating the graphical analysis of these surfaces. An application to the analysis and comparison of electrostatic surface potentials in the active sites of three serine proteases is presented.

APA, Harvard, Vancouver, ISO, and other styles

49

Naeger, Aaron R., Brian A. Colle, Na Zhou, and Andrew Molthan. "Evaluating Warm and Cold Rain Processes in Cloud Microphysical Schemes Using OLYMPEX Field Measurements." Monthly Weather Review 148, no. 5 (April 29, 2020): 2163–90. http://dx.doi.org/10.1175/mwr-d-19-0092.1.

Full text

Abstract:

Abstract Field observations from the Olympic Mountain Experiment (OLYMPEX) around western Washington State during two atmospheric river (AR) events in November 2015 were used to evaluate several bulk microphysical parameterizations (BMPs) within the Weather Research and Forecasting (WRF) Model. These AR events were characterized by a prefrontal period of stable, terrain-blocked flow with an abundance of cold rain over the lowland region followed by less stable, unblocked flow with more warm rain, and a shift in the largest precipitation amounts to over the windward Olympic slopes. Our WRF simulations underpredicted the precipitation by 19%–36% in the Morrison (MORR) and Thompson (THOM) BMPs and 10%–23% in the predicted particle properties (P3) BMP, with the largest underpredictions over the windward slopes during the more convective, unblocked flow conditions. Several important processes related to the BMPs led to the differences in simulated precipitation. First, the prognostic single ice category parameterization in the P3 scheme promoted a more realistic evolution of rimed particles and larger cold rain production, which led to the lowest underpredictions in precipitation among the schemes. Second, efficient melting processes associated with the production of nonspherical ice and snow in the P3 and THOM BMPs, respectively, promoted a more realistic transition to rain fall speeds within the warm layer compared to the spherical snow assumption in MORR. Last, all BMPs underpredict the contribution of warm rain processes to the surface precipitation, particularly during the unblocked flow period, which may be partly explained by too weak condensational and collisional growth processes due to the neglect of turbulence parameterizations within the schemes.

APA, Harvard, Vancouver, ISO, and other styles

50

Klingensmith, Jon D., Saygin Sop, Mete Naz, Maria Fernandez-del-Valle, and H. Felix Lee. "Three-dimensional modeling and assessment of cardiac adipose tissue distribution." Journal of Biomedical Graphics and Computing 8, no. 1 (January 14, 2018): 14. http://dx.doi.org/10.5430/jbgc.v8n1p14.

Full text

Abstract:

Objective: The layer of fat that accumulates around the heart, called cardiac adipose tissue (CAT), can influence the development of coronary disease and is indicative of cardiovascular risk. While volumetric assessment of magnetic resonance imaging (MRI) can quantify CAT, volume alone gives no information about its distribution across the myocardial surface, which may be an important factor in risk assessment. In this study, a three-dimensional (3D) modeling technique is developed and used to quantify the distribution of the CAT across the surface of the heart.Methods: Dixon MRI scans, which produce a registered 3D set of fat-only and water-only images, were acquired in 10 subjects for a study on exercise intervention. A previously developed segmentation algorithm was used to identify the heart and CAT. Extracted contours were used to build 3D models. Procrustes analysis was used to register the heart models and an iterative closest point algorithm was used to register and align the CAT models for calculation of CAT thickness. Rays were cast in directions specified by a spherical parameterization of elevation and azimuthal angles, and intersections of the ray with the CAT surface were used to calculate the thickness at each location. To evaluate the effects of the spherical parameterization on the thickness estimates, a set of synthetic models were created with increasing major-to-minor axis ratios.Results: Based on the validation in the synthetic models, the average error in CAT thickness ranged from 1.25% to 17.3% for increasing major-to-minor axis ratio.Conclusions: A process was developed, based on Dixon MRI data, to provide 3D models of the myocardial surface and the cardiac fat. The models can be used in future segmentation algorithm development and for studies on changes in cardiac fat as a result of various interventions.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!