• Title/Summary/Keyword: implicit

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A Scalable Semi-Implicit Method for Realtime Cloth Simulatio (계산량 조정이 가능한 실시간 옷감 시뮬레이션 방법)

  • Kim Myoung-Jun
    • The KIPS Transactions:PartA
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    • v.13A no.2 s.99
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    • pp.177-184
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    • 2006
  • Since well-known explicit methods for cloth simulation were regarded unstable for large time steps or stiff springs, implicit methods have been proposed to achieve the stability. Large time step makes the simulation fast, and large stiffness enables a less elastic cloth property. Also, there have been efforts to devise so-called semi-implicit methods to achieve the stability and the speed together. In this paper we improve Kang's method (Kang and Cho 2002), and thus devise a scalable method for cloth simulation that varies from an almost explicit to a full implicit method. It is almost as fast as explicit methods and, more importantly, almost as stable as implicit methods allowing large time steps and stiff springs. Furthermore, it has a less artificial damping than the previously proposed semi-implicit methods.

Implementation of a Double Z-buffer Antialiasing Method for Implicit Surfaces (IMPLICIT 곡면을 위한 더블 Z-버퍼 앤티 앨리어싱 방법 구현)

  • 김학란;박화진
    • Proceedings of the Korea Multimedia Society Conference
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    • 2002.11b
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    • pp.497-502
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    • 2002
  • 레이 트레이싱이나 텍스쳐 맵핑에 의한 Implicit 곡면에서의 앤티 앨리어싱을 위한 방법으로 일반적으로 stochastic 샘플링 방법이 많이 사용되고 있다. 하지만 이 방법은 복잡한 함수로 표현된 Implicit 곡면에 더 많은 복잡한 계산을 요구하며 이에 따라 처리 시간과 비용이 많이 든다. 본 논문에서는 복셀(voxel)로 표현되는 Implicit 곡면에서 효율적인 방법 및 계산으로 앨리어싱을 감소시키기 위하여 shifted 더블 Z-버퍼를 이용하였으며, 또한 box-filter와 tent-filter를 적용함으로써 양질의 Implicit 곡면 이미지를 표현하였다.

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The Design and Implementation of Implicit Object Classes for Geometric Modeling System (형상 모델링을 위한 음함수 객체의 설계 및 구현)

  • Park, Sang-Kun;Chung, Seong-Youb
    • Korean Journal of Computational Design and Engineering
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    • v.13 no.3
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    • pp.187-199
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    • 2008
  • This paper describes a C++ class hierarchy of implicit objects for geometry modeling and processing. This class structure provides a software kernel for integrating many various models and methods found in current implicit modeling areas. The software kernel includes primitive objects playing a role of unit element in creating a complex shape, and operator objects used to construct more complex shape of implicit object formed with the primitive objects and other operators. In this paper, class descriptions of these objects are provided to better understand the details of the algorithm or implementation, and its instance examples to show the capabilities of the object classes for constructive shape geometry. In addition, solid modeling system shown as an application example demonstrates that the proposed implicit object classes allow us to carry out modern solid modeling techniques, which means they have the capabilities to extend to various applications.

Development of a Three-Dimensional, Semi-Implicit Hydrodynamic Model with Wetting-and-Drying Scheme (조간대 처리기법을 포함한 3차원 Semi-Implicit 수역학모델 개발)

  • Lee, Kyung-Sun;Park, Kyeong;Oh, Jeong-Hwan
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.12 no.2
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    • pp.70-80
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    • 2000
  • Princeton Ocean Model (POM) is modified to construct a three-dimensional, semi-implicit hydro¬dynamic model with a wetting-and-drying scheme. The model employs semi-implicit treatment of the barotropic pressure gradient terms and the vertical mixing terms in the momentum equations, and the velocity divergence term in the vertically-integrated continuity equation. Such treatment removes the external mode and thus the mode splitting scheme in POM, allowing the semi-implicit model to use a larger time step. Applied to hypothetical systems, both the semi-implicit model and POM give nearly the same results. The semi-implicit model, however, runs approximately 4.4 times faster than POM showing its improved computational efficiency. Applied to a hypothetical system with intertidal flats, POM employing the mode splitting scheme produces noises at the intertidal flats, that propagate into the main channel resulting in unstable current velocities. Despite its larger time step, the semi-implicit model gives stable current velocities both at the intertidal flats and main channel. The semi-implicit model when applied to Kyeonggi Bay gives a good reproduction of the observed tides and tidal currents throughout the modeling domain, demonstrating its prototype applicability.

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The Study of Implicit Self-Esteem and Depression and Fashion Competency (암묵적 자존감 및 우울감과 패션능숙성에 관한 연구)

  • Lee, Sae Eun;Son, Hyungjin;Lee, Yuri;Ha, Jisoo
    • Journal of the Korean Society of Clothing and Textiles
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    • v.41 no.4
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    • pp.575-584
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    • 2017
  • Previous research has investigated the influence of explicit self-esteem and depression. These studies did not examine the implicit self-esteem and depression that exist in the internal unconscious of humans that are not influenced by prejudice and social desirability. This study identifies that fashion competency (FC) encourages the implicit self-esteem and relieves the implicit depression. Implicit self-esteem and depression were measured by Implicit Association Test (IAT) utilizing reaction; FC was surveyed based on questionnaires. The data collected were analyzed using factor analysis. FC was then composed of three factors of fashion involvement, fashion innovativeness and self-confidence in fashion coordination. The results of comparing the index values that indicate IA SE (implicit association self-esteem) and IA DE (implicit association depression) of each FC group indicated that a higher FC results in a higher IA SE and lower IA DE; therefore, individuals with a higher fashion competence have a higher implicit self-esteem and a sense of well-being. The findings support previous studies in that the FC tends to be positively related to quality of life in young people.

Extended Adaptively Sampled Distance Fields Method for Rendering Implicit Surfaces with Sharp Features (음함수 곡면의 날카로운 형상 가시화를 위한 확장 Adaptively Sampled Distance Fields 방법)

  • Cha J.H.;Lee K.Y.;Kim T.W.
    • Korean Journal of Computational Design and Engineering
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    • v.10 no.1
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    • pp.27-39
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    • 2005
  • Implicit surfaces are geometric shapes which are defined by implicit functions and exist in three-dimensional space. Recently, implicit surfaces have received much attention in solid modeling applications because they are easy to represent the location of points and to use boolean operations. However, it is difficult to chart points on implicit surfaces for rendering. As efficient rendering method of implicit surfaces, the original Adaptively Sampled Distance Fields (ADFs) $method^{[1]}$ is to use sampled distance fields which subdivide the three dimensional space of implicit surfaces into many cells with high sampling rates in regions where the distance field contains fine detail and low sampling rates where the field varies smoothly. In this paper, in order to maintain the sharp features efficiently with small number of cells, an extended ADFs method is proposed, applying the Dual/Primal mesh optimization $method^{[2]}$ to the original ADFs method. The Dual/Primal mesh optimization method maintains sharp features, moving the vertices to tangent plane of implicit surfaces and reconstructing the vertices by applying a curvature-weighted factor. The proposed extended ADFs method is applied to several examples of implicit surfaces to evaluate the efficiency of the rendering performance.

Implicit Moving Least Squares Difference Method for 1-D Moving Boundary Problem (1차원 자유경계문제의 해석을 위한 Implicit 이동최소제곱 차분법)

  • Yoon, Young-Cheol
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.5
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    • pp.439-446
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    • 2012
  • This paper presents an implicit moving least squares(MLS) difference method for improving the solution accuracy of 1-D free boundary problems, which implicitly updates the topology change of moving interface. The conventional MLS difference method explicitly updates the moving interface; it requires no iterative solution procedure but results in the loss of accuracy. However, the newly developed implicit scheme makes the total system nonlinear involving iterative solution procedure, but numerical verification show that it dramatically elevates the solution accuracy with moderate computation increase. Through numerical experiments for melting problems having moving singularity, it is verified that the proposed method can achieve the second order accuracy.

The effects of explicit and implicit pragmatic instruction in Korean request strategies for Chinese learners (명시적 교수와 암시적 교수가 요청 화행 전략 표현 학습에 미치는 효과 비교 연구 - 중국인 한국어 학습자를 대상으로 -)

  • Lee, YeonKyung
    • Journal of Korean language education
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    • v.25 no.1
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    • pp.115-144
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    • 2014
  • The purpose of this paper is to compare the two different instruction methods for Korean learners of academic purposes in learning request expression. Participants were divided into two groups, explicit and implicit group. Both groups viewed several scenes from the drama that involved native speakers interacting in different situations. The instructional treatment for the explicit group included metapragmatic information while the treatment for the implicit group did not. On the other hand, the treatment for the implicit group followed implicit techniques, which were repetition of the video presentation and a script reading activity. This study was made up of a pre-test, a post-test, and a delayed-test. The pre-test was conducted prior to the instructional treatment. The post-test was administered a day after the last instruction and the delayed-test was conducted five weeks after the treatments. Two types of tests, speaking and writing, were used in this study to examine subjects' knowledge of Korean request. The result of this research reveals that implicit treatment was more effective than explicit treatment in Korean learners' request acquisition. This results might have been due to the operationalization of the implicit condition in this study. Implicit instruction may help language learners make rules by themselves through tasks.