• Advances in Computational Design
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• 제5권4호
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• pp.397-416
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• 2020

Functionally graded material (FGM) illustrates a novel class of composites that consists of a graded pattern of material composition. FGM is engineered to have a continuously varying spatial composition profile. Current work focused on buckling analysis of beam made of stepwise linear and quadratic graded material in axial direction subjected to axial span-load with piecewise function and rested on shear layer based on classical beam theory. The various boundary and natural conditions including simply supported (S-S), pinned - clamped (P-C), axial hinge - pinned (AH-P), axial hinge - clamped (AH-C), pinned - shear hinge (P-SHH), pinned - shear force released (P-SHR), axial hinge - shear force released (AH-SHR) and axial hinge - shear hinge (AH-SHH) are considered. To the best of the author's knowledge, buckling behavior of this kind of Euler-Bernoulli beams has not been studied yet. The equilibrium differential equation is derived by minimizing total potential energy via variational calculus and solved analytically. The boundary conditions, natural conditions and deformation continuity at concentrated load insertion point are expressed in matrix form and nontrivial solution is employed to calculate first buckling loads and corresponding mode shapes. By increasing truncation order, the relative error reduction and convergence of solution are observed. Fast convergence and good compatibility with various conditions are advantages of the proposed method. A MATLAB code is provided in appendix to employ the numerical procedure based on proposed method.

• 한국실내디자인학회논문집
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• 제13권5호
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• pp.11-20
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• 2004

F. L. Wright was, from his early days, influenced by Japanese Culture and endeavored his original concept of orgonic orchitecture. In his 1st Golden Age, he devoted to establish an architectural concept of Organism which was proved by the theories of New Science and also had been universal in ancient Orient. Later, in his 2nd Golden Age, he tried to embody his unique concept in prairie houses and office buildings. The organic structure and spatial unit that actually applied to these works, were good examples of realization of the simplicity and continuity which he found out in Japanese culture. This paper is to study on the influence of Japanese culture on a course of Wright's embodying his organic architecture, and to study on a way of its realization in his works. To be concrete, main contents of the study are as follows; 1) the relationship between Wright's integrate perception and the orientalism 2) the influence of the traditional Japanese painting like woodblock prints and the aesthetic theory of the traditional Japanese pictorial art on Wright's design principles 3) the influence of Wright's experiences in Japan on his design principles 4) the influence of Wright's analysis of the traditional Japanese dwelling on his design principles 5) the course of Wright's embodying his organic architecture concept, and the way of its realization in his works.

• 한국실내디자인학회논문집
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• 제20권5호
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• pp.245-253
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• 2011

As interests towards health rapidly increase recently, interests and demand for hospital interior space are increasing as well. Therefore, most of today's hospitals that have been functionally designed are transforming into healing environments that consider psychological aspects, in order to assist patients forget about fear, desperation and have peace of mind. With such creation method of healing environment, natural elements can be applied to spaces in order to allow patients feel vitality, hope and adapt positive thinking, and these can eventually lead to affluent fusion of humans, nature and space. Through case analyses of how natural elements are applied to hospital's interior space, this study understands its characteristics. According to the findings, nature is largely classified into light, water, plant, stone/soil, and its application methods can be classified into center, transition, continuity, division, opening and closure. As evident from case analyses, application of natural elements to hospital's interior space promotes exchanges among patients through community formation, and achieves the effect of spatial concentration and public place. Also, ambiguity of exterior and interior boundary creates a sense of expansion and continuous effect, and can also provide a healing environment that can fully absorb natural environment open to patients. This study aims to be of service when designing hospital's interior space, with its natural element application method for healing environment research, and wishes for continuous studies on healing environments with more diverse methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권5호
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• pp.1856-1869
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• 2015

This paper addresses the issues of 3D human activity detection, tracking and recognition from RGB-D video sequences using a feature structured framework. During human tracking and activity recognition, initially, dense depth images are captured using depth camera. In order to track human silhouettes, we considered spatial/temporal continuity, constraints of human motion information and compute centroids of each activity based on chain coding mechanism and centroids point extraction. In body skin joints features, we estimate human body skin color to identify human body parts (i.e., head, hands, and feet) likely to extract joint points information. These joints points are further processed as feature extraction process including distance position features and centroid distance features. Lastly, self-organized maps are used to recognize different activities. Experimental results demonstrate that the proposed method is reliable and efficient in recognizing human poses at different realistic scenes. The proposed system should be applicable to different consumer application systems such as healthcare system, video surveillance system and indoor monitoring systems which track and recognize different activities of multiple users.

• 정보저장시스템학회논문집
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• 제5권1호
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• pp.19-35
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• 2009

The present work is an experimental and analytical study on a flexible disk rotating close to a rigid rotating disk in open air. In the analytical study, the air flow in the gap between the flexible disk and the rigid disk is modeled using Navier-Stokes and continuity equations while the flexible disk is modeled using the linear plate theory. The flow equations are discretized using the cell centered finite volume method (FVM) and solved numerically with semi-implicit pressure-linked equations (SIMPLE algorithm). The spatial terms in the disk equation are discretized using the finite difference method (FDM) and the time integration is performed using fourth-order Runge-Kutta method. An experimental test-rig is designed to investigate the dynamics of the flexible disk when rotating close to a co-rotating, a counter-rotating and a fixed rigid disk, which works as a stabilizer. The effects of rotational speed, initial gap height and inlet-hole radius on the flexible disk displacement and its vibration amplitude are investigated experimentally for the different types of stabilizer. Finally, the analytical and experimental results are compared.

• 한국수산과학회지
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• 제30권6호
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• pp.1044-1055
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• 1997

To find out generating mechanism of eddies in the polar frontal zone of the East Sea, we carried out a series of numerical experiments using the nonlinear $1^{1/2}-layer$ model allowing the effect of the polar front. We assumed the polar front at about $39^{\circ}N$ in zonal direction with the cold water region in the northern part and the warm water region in the southern part of the model ocean. To examine the effect of the frontal motion without the influence of the Tsushima Current from the beginning of the geostrophic adjustment, the initial state of the model ocean was assumed motionless. Eastward current was caused by the geostrophic adjustment process in the polar frontal zone that induced a steady northward coastal current along the Korean coast to satisfy the mass continuity. The overshooting of this coastal current acted as an initial disturbance of the zonal flow field which caused meanders and eddies. The spatial scales of eddies were in good agreement with the baroclinic instability theory.

• Asian Journal of Atmospheric Environment
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• 제2권1호
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• pp.60-67
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• 2008

The spatial limitations of urban environments in general lead to invention and design of a wide range of underground transportation systems such as subways, underground roads and paths, etc. Among them, the application of subway systems in metropolitan cities is most commonly observed to ease those confronted difficulties on this purpose. It in turn leaves passengers and workers to be exposed to indoor air potentially polluted by various sources existing in this underground environment. Specifically when considering the IAQ in a subway station, there exist many IAQ-related parameters to be counted either as individual or as integrated exposures. In this study, a model system has been developed to manage the general IAQ in a subway station. Field survey and $CO_2$ measurements were initially conducted to analyze and understand the relationship between the indoor and outdoor air quality while considering the internal pollution sources such as passengers, subway trains, etc. The measurement data were then employed for the model development with other static information. For the model development, the algorithm of simple continuity was built and applied to model the subway IAQ concerned. In this paper, the recent updated draft version of model developed will be reported and demonstrated.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.659-663
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• 2010

In recent, flood inundation damages by hydraulic structure failures have increased drastically and thus a variety of countermeasures were needed to minimize such damages. A real-time flood inundation prediction technique is essential to protect and mitigate flood inundation damages. In the context of real time flood inundation modeling, this study aims to develop a grid based two-dimensional numerical method for flood inundation modeling using globally-available DEM data: SRTM with $90m{\times}90m$ spatial resolution. The newly-developed model guarantees computational efficiency in terms of geometric data processing by direct application of DEM for flood inundation modeling and also have good compatibility with various types of raster data when compared to a commercial model such as FLUMEN. The model, which employed the leap-frog algorithm to solve shallow water and continuity equations, can simulate inundating flow from channel to lowland and also returning flow from lowland to channel by comparing water levels between channel and lowland in real time. We applied the model to simulate the BaekSan levee break in the Nam river during a flood period from August 10 to 13, 2002. The simulation results had good agreements with the field-surveyed data in terms of inundated area and also showed physically-acceptable velocity vector maps with respect to inundating and returning flows.

• 한국산업정보학회논문지
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• 제6권2호
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• pp.16-22
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• 2001

본 논문에서는 화상자료의 특성인 이웃 화소간의 종속성을 표현하는데 적합한 깁스분포를 바탕으로 특징벡터를 추출하여 변형된 글자를 인식하는 새로운 방법을 제안하였다. 추출된 특징벡터는 이미지의 크기, 위치, 회전에 대하여 불변한 특성을 갖는 2차원 조건부 모멘트로 구성된다. 변형된 글자 인식을 위한 알고리즘은 특징벡터 추출하는 과정과 패턴을 인식하는 과정으로 구성하였다. (i) 특징벡터는 하나의 이미지에 대하여 추정된 조건부 깁스분포를 바탕으로 2차원 조건부 모멘트를 계산하여 추출한다. (ii) 변형된 문자 인식은 제안된 판별거리함수를 계산하여 최소거리를 산출한 미지의 변형된 문자를 원형문자로 인식한다. 제안된 방법에 대한 성능평가를 위하여, 생성된 훈련 데이터를 만들어 Workstation에서 실험 한 결과 96%이상의 인식성능이 있음을 밝혔다.

• 한국환경과학회지
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• 제1권1호
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• pp.19-33
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• 1992

The high oxidants, which occur the daily maximum concentrations in the afternoon, are transported into the other region via long range transport mechanisms or trapped within the shallow mixing boundary layer and then removed physically (deposition, transport by mountain wind, etc.) and chemically (reaction with local sources). Therefore, modeling formation of photochemical oxidants requires a complex description of both chemical and meteorolog ital processecs . In this study, as a part of air quality studies, we reviewed various aspects of photochemical modeling on the basis of currently available literature. The result of the review shows that the model is based on a set of coupled continuity equations describing advection, diffusion, transport, deposition, chemistry, emission. Also photochemical oxidant models require a large amount of input data concerned with all aspects of the ozone life cycle. First, emission inventories of hydrocarbon and nitrogen oxides, with appropriate spatial and temporal resolution. Second, chemical and photochemical data allowing the quantitative description of the formation of ozone and other photochemically-generated secondary pollutants. Third, dry deposition mechanisms particularly for ozone, PAN and hydrogen peroxide to account for their removal by absorption on the ground, crops, natural vegetation, man-made and water surfaces. Finally, meteorological data describing the transport of primary pollutants away from their sources and of secondary pollutants towards the sensitive receptors where environmental damage may occur. In order to improve our present study, shortcomings and limitation of existing models are pointed out and verification Process through observation is emphasized.