• 한국농공학회논문집
• /
• 제60권5호
• /
• pp.41-54
• /
• 2018

A method to account a detention in a rice paddy field in hydrologic modeling was tested at plot and watershed scales. Hydrologic Simulation Program - Fortran (HSPF) and its one of surface runoff modeling method, i.e Surface-Ftable, were used to simulate a inundated condition in a rice paddy culture for a study plot and basins in Saemangeum watershed. Surface-Ftable in HSPF defines surface runoff ratio with respect to surface water depth in a pervious land segment, which can be implemented to the feature of water management in a rice paddy field. A Surface-Ftable for paddy fields in Saemangeum watershed was developed based on the study paddy field monitoring data from 2013 to 2014, and was applied to Jeonju-chun and Jeongeup-chun basins which comprise 12% and 22% of paddy fields in the basins, respectively. Four gaging stations were used to calibrate and validate the watershed models for the period of 2009 and 2013. Model performed 7.13% and 9.68% in PBIAS, and 0.94 and 0.90 in monthly NSE during model calibrations at Jeonju and Jeongeup stations, respectively, while the models were validated its applicability at Hyoja and Gongpyung stations. The comparison of results with and without considering detention effect of paddy fields confirmed the validity of the Surface-Ftable method in modeling watersheds containing rice paddy fields.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2006년도 춘계학술발표대회
• /
• pp.1315-1318
• /
• 2006

모형 설계와 도형의 생성은 점, 곡선, 기울기과 같은 특정 속성들의 정보로 만들어 진다. 도형을 생성할 때 곡면 조각, 움직이는 곡선과 점, 일반적인 곡선, 연속 혹은 닫힌 곡선, 빠른 계산들은 중요하게 생각 되는 모델링 개념이다. 이 논문에서는 Attribute Based $Modeling^{TM}(A-B\;Modeling^{TM})$ surface을 사용하여 디자인을 디자인할 때 필요한 Multi-sided patch의 설계와 인터페이스를 구현하고자 한다.

• 한국CDE학회논문집
• /
• 제12권5호
• /
• pp.344-353
• /
• 2007

In this paper, we address the problem of robust geometric modeling with emphasis on surface to surface intersections. We consider the topology and the numerical accuracy of an intersection curve to find the best approximation to the exact one. First, we perform the topological configuration of intersection curves, from which we determine the starting and ending points of each monotonic intersection curve segment along with its topological structure. Next, we trace each monotonic intersection curve segment using a validated ODE solver, which provides the error bounds containing the topological structure of the intersection curve and enclosing the exact root without a numerical instance. Then, we choose one approximation curve and adjust it within the bounds by minimizing an objective function measuring the errors from the exact one. Using this process, we can obtain an approximate intersection curve which considers the topology and the numerical accuracy for robust geometric modeling.

• 한국정보과학회논문지:시스템및이론
• /
• 제34권1호
• /
• pp.38-48
• /
• 2007

본 논문에서는 NURBS(Non-Uniform Rational B-Splines)로 표현된 3차원 곡면을 복원하기 위한 영상 기반 곡면 모델링 기법을 제안한다. 카메라 보정이 수행된 복수의 영상으로부터 사용자가 대응곡선을 지정하면 카메라의 정보를 이용하여 대응 곡선의 3차원 복원을 수행한다. 사용자 인터페이스에 의해 각 영상에서 곡선을 지정하기 위하여 본 논문에서는 NURBS 곡선을 이용하였으며 bilinear surface, ruled surface, generalized cylinder, surface of revolution등의 기본 곡면뿐 아니라 skinned surface, swept surface, boundary patch등의 고급 곡면 생성을 지원하여 다양한 모양의 곡면 물체를 모델링 할 수 있다. 또한 영상을 기반으로 view-dependent 텍스처 생성방법을 지원하여 좀더 사실적인 곡면의 복원을 수행한다. 생성된 3차원 곡선 또는 곡면은 VRML과 같은 표준 형식으로 출력하여 재사용할 수 있다.

• 산업기술연구
• /
• 제43권1호
• /
• pp.33-41
• /
• 2023

This paper provides a general overview of surface catalytic recombination in hypersonic flow. The surface catalytic recombination phenomena is elaborated in terms of its general overview and numerical modeling associated with it. The general overview of the surface catalytic recombination phenomena describes the elementary surface reactions for the surface catalytic and the role of the surface catalytic recombination efficiency in the heat transfer determination. In the numerical modeling, the surface catalytic recombination is described based on the stagnation-point boundary layer analysis, and finite-rate surface reaction modeling. Throughout this overview manuscript, a general understanding of this phenomena is obtained and can be used as foundation for deeper application with the numerical computational fluid dynamics (CFD) flow solver to estimate the surface heat transfer in the hypersonic vehicles.

• 한국학교수학회논문집
• /
• 제14권1호
• /
• pp.43-64
• /
• 2011

본 연구의 목적은 초등학교 6학년 아동을 대상으로 하여 수학적 모델링을 적용한 입체도형의 겉넓이 수업에서 학습이 이루어지는 동안 나타나는 학생들의 추상화 과정을 분석하고 학습에 대한 사전 사후의 겉넓이 이해 검사 결과를 비교함으로써 겉넓이에 대한 이해 정도를 알아보고자 함이다. 학생들의 추상화 과정을 분석한 결과 학생들은 주어진 수학적 모델링 과제를 해결하는 동안 수학적 원리를 포함한 모델을 개발하면서 모둠별로 각기 다른 수준의 추상화 과정을 나타냈으며, 겉넓이 이해 검사 결과 사후 검사에서 학생들의 겉넓이에 대한 이해가 향상되었다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1996년도 추계학술대회 논문집
• /
• pp.774-778
• /
• 1996

Developed in this research is a surface modeling kernel for various CAD/CAM applications. Its internal surface representations are rational parametric polynomials, which are generalizations of nonrational Bezier, Ferguson, Coons and NURBS surface, and are very fast in evaluation. The kernel is designed under the OOP concepts and coded in C++ on PCs. The present implementation of the kernel supports surface construction methods, such as point data interpolation, skinning, sweeping and blending. It also has NURBS conversion routines and offers the IGES and ZES format for geometric information exchange. It includes some geometric processing routines, such as surface/surface intersection, curve/surface intersection, curve projection and so forth. We are continuing to work with the kernel and eventually develop a B-Rep based solid modeler.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 1999년도 추계학술대회
• /
• pp.565-574
• /
• 1999

In reverse engineering area, it is rapidly developing reconstruction of surfaces from scanning or digitizing data, but geometric models of existing objects unavailable many industries. This paper describes new methodology of reverse engineering area, good strategies and important algorithms in reverse engineering area. Furthermore, proposing reconstruction of surface technique is presented. A method find base geometry and blending surface between them. Each based geometry is divided by triangular patch which are compared their normal vector for face grouping. Each group is categorized analytical surface such as a part of the cylinder, the sphere, the cone, and the plane that mean each based geometry surface. And then, each based geometry surface is implemented infinitive surface. Infinitive average surface's intersections are trimmed boundary representation model reconstruction. This method has several benefits such as the time efficiency and automatic functional modeling system in reverse engineering. Especially, it can be applied 3D scanner and 3D copier.

• 한국정밀공학회지
• /
• 제20권10호
• /
• pp.156-163
• /
• 2003

This research presents modeling of a functional surface which is a constructed free-formed surface. The modeling introduced in this paper adopts modified B-spline that is utilizing approximating technique. The modified B-Spline is constructed with altered control vertices. It is applied to measure points on a surface of an impeller blade. This research builds a surface-modeler accepting inputs of measured points. Generation of cutter-paths for NC machining employs the model of the constructed surfaces. The machined surfaces which is generated in several cases are compared in the aspect of machining accuracy.

• 콘크리트학회논문집
• /
• 제21권2호
• /
• pp.153-158
• /
• 2009

콘크리트 표면에 4개의 전극배열을 이용한 비파괴 표면측정법을 통하여 철근의 피복을 벗겨내지 않고도 콘크리트 내 철근의 부식상태 및 철근의 배치상태를 추정할 수 있다. 표면측정법 모델링은 부식된 철근과 주위 콘크리트사이의 계면 임피던스가 콘크리트 표면에서 측정된 임피던스와 어떤 관련이 있는지를 보여준다. 본 연구에서는 콘크리트에 매립된 철근 크기와 콘크리트 피복두께 등의 탐지를 위하여 철근부식 표면측정 모델링을 이용하였다. 모델링 결과 철근 크기가 D10에서 D35로 커짐에 따라 표면임피던스 변화가 나타났으며, 또한 콘크리트 피복두께가 0.02 m에서 0.1 m로 커짐에 따라 그 변화에 대한 영향이 표면측정 임피던스를 통해 나타났다. 그러므로 표면측정법 모델링을 통하여 콘크리트 내 철근부식반응을 시뮬레이션 할 수 있으며, 동시에 철근직경과 매입 깊이 등에 대한 정보도 얻을 수 있음 알 수 있다.