• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.2356-2361
• /
• 2005

In this paper, we present a complete isotropy analysis of a caster wheeled omnidirectional mobile robot(COMR) with nonredundant/redundant actuation. The motivation of this work is that the omnidirectional mobility loses significance in motion control unless the isotropy characteristics is maintained well. First, with the characteristic length introduced, the kinematic model of a COMR is obtained based on the orthogonal decomposition of the wheel velocities. Second, a general form of the isotropy conditions of a COMR is given in terms of physically meaningful vector quantities which describe the wheel configurations. Third, for all possible nonredundant and redundant actuation sets, the algebraic expressions of the isotropy conditions are derived to completely identify the isotropic configurations of a COMR. Fourth, the number of the isotropic configurations and the characteristic length required for the isotropy are discussed.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
• /
• pp.46-47
• /
• 2017

Korea rapidly arranged urbanization and overpopulation with high growth of economy and all kinds of decrepit facilities are scattered all over the downtown. If there is a strong wind in fire, fire is rapidly increased by various fire spread factors. And Korea cannot build prediction model of urban fire combustion phenomena because there is no studies that physically explains the suitable flame phenomena for its real state. In this study, based on the Japanese Urban fire simulation to target the traditional market area and suitability of fire risk assessment were reviewed.

• 소성∙가공
• /
• 제9권1호
• /
• pp.59-65
• /
• 2000

Most studies of failure analysis in ductile metals have been based on the classical plasticity theory using the local constitutive relations. These frequently yields a physically unrealistic solution, in which a numerical prediction of the onset of a deformation localization shows an inherent mesh-size sensitivity. A one way to remedy the spurious mesh sensitivity resulted in the unreasonable results is to incorporate the non-local plasticity into the simulation model, which introduce an internal (material) length-scale parameter into the classical constitutive relations. In this paper, a non-local version of the modified Gurson constitutive relation has been introduced into the finite element formulation of the simulation for plane strain compression of the visco elastic-plastic void material. By introducing the non-local constitutive relations we could successfully removed the inherent mesh-size sensitivity for the prediction of the deformation localization. The effects of non-local constitutive relation are discussed in terms of the load-stroke curve and the strain distributions accross the shear band.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
• /
• pp.883-887
• /
• 1998

Hydration is the main reason for the growth of the material properties. A exact parameter to control the chemical and physical process is not the time, but the degree of hydration. Therefore, it is reasonable that development all material properties should be formulated in terms of degree of hydration. Mathematical formulation of degree of hydration is based on combination of reaction rate functions. The effect of moisture conditions as well as temperature on the rate of reaction is considered in the degree of hydration model. This effect is subdivided into two contributions: water shortage and water distribution. The former is associated with the effect of on the progress of hydration. The water needed for progress of hydration do not exist and there is not enough space for the reaction products to form. The latter is associated with the effect of free capillary water distribution in the pore system. Physically absorption layer does not contribute to progress of hydration and only free water is available for further hydration.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 D
• /
• pp.3245-3247
• /
• 2000

We present an interactive virtual bronchoscopy method, which uses a tree structure of the objects and physically based camera control model. The proposed method archieves faster response by rendering only visible branches using the tree structure of the bronchus. A collision detection algorithm supplies a convenient and intuitive mechanism for examining the bronchus inner surface while a voiding collisions. We have improved the performances of navigation speed in virtual bronchoscopy.

• 한국CDE학회논문집
• /
• 제14권5호
• /
• pp.346-354
• /
• 2009

BRDF (bidirectional reflectance distribution function) is critical in realistic simulation of material appearances since it models the directional characteristics of reflection of light. Although many BRDF models have been proposed so far, it is still not easy to find one specific model that could represent all the reflection properties of real materials such as generalized diffusion, off-specular reflection, Fresnel effect, and back scattering. In this paper, we compare three BRDF models including B-spline volume BRDF (BVB), Cook-Torrance, and Lafortune in their ability to represent the measured BRDF data for physically-based rendering. We show that B-spline volume BRDF surpass the others in quality of data fitting and rendering, especially for materials without specular reflections.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2013년도 추계 학술논문 발표대회
• /
• pp.226-227
• /
• 2013

Korea rapidly arranged urbanization and overpopulation with high growth of economy and all kinds of decrepit facilities are scattered all over the downtown. If there is a strong wind in fire, fire is rapidly increased by various fire spread factors. And Korea cannot build prediction model of urban fire combustion phenomena because there is no studies that physically explains the suitable flame phenomena for its real state. In this study, based on the Japanese Urban fire simulation to target the building congested Area and suitability of fire risk assessment were reviewed.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
• /
• pp.87-88
• /
• 2013

Korea rapidly arranged urbanization and overpopulation with high growth of economy and all kinds of decrepit facilities are scattered all over the downtown. If there is a strong wind in fire, fire is rapidly increased by various fire spread factors. And Korea cannot build prediction model of urban fire combustion phenomena because there is no studies that physically explains the suitable flame phenomena for its real state. In this study, based on the Japanese Urban fire simulation to target the wooden building congested Area and suitability of fire risk assessment were reviewed.

• 한국화재소방학회:학술대회논문집
• /
• 한국화재소방학회 2009년도 춘계학술논문발표회 논문집
• /
• pp.473-479
• /
• 2009

본 연구는 한국형 도시화재의 물리적 연소성상 예측 모델구축을 위한 기초연구로 일본의 시가지화재시뮬레이션의 구성에 대하여 살펴보고 우리나라의 화재경계지구의 현장조사를 토대로 시뮬레이션을 활용한 Case Study를 수행하였다. 이에 따라 향후 일본과의 국제공동연구의 방향을 설정하여 안전한 방재도시 구현에 이바지하고자 한다.

• 한국화재소방학회:학술대회논문집
• /
• 한국화재소방학회 2009년도 춘계학술논문발표회 논문집
• /
• pp.311-317
• /
• 2009

우리나라에서 발생하는 화재의 대부분은 건축물 화재이며, 이중 노후화된 시가지 등 화재에 취약한 지역에서 화재발생시 도시화재로 확대될 우려가 높다. 이러한 도시화재 확대를 방지하기 위한 도시화재의 물리적 연소성상예측모델과 도시화재 리스크평가기법의 개발이 필요하다. 본 연구에서는 우리나라의 도시화재위험성평가 구축을 위한 한 일 공동연구체계와 주요 대상인 화제경계지구에 대하여 소개하였다.