• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2530-2538
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• 2015

The pixel value of depth image is depth value so that different objects which are placed on nearby position have similar pixel value. Moreover, the pixels of depth image have distinct pixel values compared to adjacent pixels while those of color image has very similar values. Accordingly distorted depth image of multiview video plus depth (MVD) needs proper error concealment methods considering the characteristics of depth image when transmission errors are happened. In this paper, classifying regions of depth image to consider edge directions and then applying adaptive error concealment methods to each region are proposed. Recovered depth images utilize with multiview video data to synthesize intermediate-view point video. The synthesized view is evaluated by objective quality metrics to demonstrate proposed method performance.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.91-100
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• 2006

This paper presents an analytical model for evaluation of crack widths in structural concrete members. The model is mathematically derived from the actual bond stress-slip relationships between the reinforcement and the surrounding concrete, and the relationships summarized in CEB-FIP Model Code 1990 are employed in this study together with the assumption of a linear slip distribution along the interface at the stabilized cracking stage. With these, the actual strains of the steel and the concrete are integrated respectively along the embedment length between the adjacent cracks so as to obtain the difference in the axial elongation. The model is applied to the test specimens available in literatures, and the predicted values are shown to be in good agreement with the experimentally measured data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.389-391
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• 2010

The Free surface influenced the wake behind a circular cylinder and its effects were investigated experimentally in a circulating water channe with the variation of water depth Instantaneous velocity fields were measured in this paper. the measured results has been compared with each other to investigate the flow characteristics of the circular cylinder's 2-dimensional section at $Re=1.0\times10^3$ using 2-frame grey level cross correlation PIV method. The flow around the circular cylinder with free surface affected the wake structure. especially, in case of d=1.0D, the boundary layer was measured in the whole area. The separation point and boundary layer of the circular cylinder could be controlled by the water depth.

• Journal of Ocean Engineering and Technology
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• v.28 no.4
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• pp.261-267
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• 2014

Because a change in the natural frequencies of a structure indicates structural health problems, monitoring the natural frequencies crucial. Long-term measurement for the Uldolmok tidal current power plant structure has shown that its natural frequencies fluctuate with a constant cycle twice a day. In this study, lab-scale tests to investigate the causes of these natural frequency fluctuations were carried out in a circulating water channel. Three independent variables in the tests that could affect the fluctuation of the natural frequencies were the water level, current velocity, and boundary condition between the specimen and the bottom of the circulating water channel. The experimental results were verified with numerical ones using ABAQUS. It was found that the fluctuation of the natural frequencies was governed by a decrease in stiffness due to the boundary condition much more than the effect of added mass. In addition, it was found that the natural frequency would decrease with an increase in the tidal current velocity because of its nonlinearity when the boundary condition was severely deteriorated due to damage.

• Journal of the Korean Geographical Society
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• v.37 no.2
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• pp.131-142
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• 2002

The community and communal folk belief are developed as spatial phenomena. So the communal folk belief express the spatial perception of inhabitants in traditional village. This study analysis the spatial characteristics of communal folk belief in traditional village. The study area is Bangchon village which consists of seven hamlets in Changhung-gun, Chollanam-do. The reset are as follows. First, the seven hamlet\`s location process in Bangchon village has been developed with spatio-temporal variations since Korea dynasty. Second, the communal folk belief in study area can be classified as Ipsok, Byolsinje\`s site, Hojeby\`s site. Third, the spatial characteristics of communal folk belief in study area are indication of each hamlet\`s boundary, indication of entrance and exit of Bangchon visage, indication of central space of Bangchon village in traditional period. Consequently, the spatial distribution of communal for belief are important indicator about spatial structure and spatial perception in traditional village\`s society.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.2
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• pp.164-170
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• 2002

Sliding mode control, as a typical method of variable structure control, has the robust characteristics for the uncertainty and the disturbance of the nonlinear system. Because, however, sliding mode control input includes a sign function that Is discontinuous on the predefined switching surface, its applications are primarily limited by the need of alleviation or reduction of chattering. In this paper, we propose a chattering alleviation strategy based on a special nonlinear function and a fuzzy system. By using the proposed control scheme, we can reduce the steady state error. Its tracking performance is as fast as that of conventional method using the fixed boundary layer. Especially, in the proposed method, we can adjust the trade-off between the steady state error and the degree of chattering by regulating the proper range of the output variable of the fuzzy system. To verify the validity of the proposed algorithm, the analysis of the control method using the fixed boundary layer and the computer simulations are shown to compare with them.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.819-827
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• 2007

A numerical algorithm for estimating precise backscattering coefficients of rice fields is proposed and its accuracy is verified in this paper. After a bunch of rice plants above water surface is modeled with a bunch of randomly oriented lossy dielectric bodies above an impedance surface and the equivalent volume currents of the lossy dielectrics are computed using the moment method. Then, the scattered fields of a rice field with many bunches are computed with a Monte Carlo method, and consequently the backscattering coefficient of the rice field is computed for various incidence angles and polarizations. Finally, the backscattering coefficient of a rice field is measured at 1.85 GHz using an R-band scatterometer system, and these experimental data are used to verify the numerical algorithm proposed in this paper. It is found that the numerical computation results agree well with the measurement data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.11
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• pp.1055-1063
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• 2012

Fluctuating wall pressures were measured using an array of 16 piezoelectric transducers beneath a turbulent boundary layer. The coating used in this experiment was an open-cell, urethane-type foam with a porosity of approximately 50 ppi. The ultimate objective of the coating is to provide a mechanical filter to reduce the wall pressure fluctuations. The boundary layer on the flat plate was measured by using a hot wire probe, and the CPM method was used to determine the skin friction coefficient. The wall pressure autospectra and streamwise wavenumber-frequency spectra were compared to assess the attenuation of the wall pressure field by the coating. The coating is shown to attenuate the convective wall pressure energy. However, the relatively rough surface of the coating in this investigation resulted in a higher mean wall shear stress, thicker boundary layer, and higher low-frequency wall pressure spectral levels compared to a smooth wall.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.691-700
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• 1998

Based on Von Karman-Donnell kinematic assumptions for laminated shells, the nonlinear vibration behaviour of antisymmetrically or asymmetrically laminated cross-ply circular cylindrical shells with clamped and simply-supported ends are studied by a multi-mode approach. A equation is formulated and satisfies the associated compatibility equation and all boundary conditions. The displacement function is assumed to take the form of the lowest linear vibration mode and to satisfy continuity of the circumferential displacement. The nonlinear vibration equation is derived by the Galerkin's method. And nonlinear frequency is obtained by using the harmonic balance method as a function of lamination parameters, material constants, aspect ratio and amplitude of vibration. The effect of initial imperfection is also included. Results of the non-linear vibration are presented for different amplitudes of initial imperfection and four sets of boundary conditions. Present results are compared well with existing analysis results.

• Korean Institute of Interior Design Journal
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• v.13 no.2
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• pp.100-108
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• 2004

인테리어 디자인학은 보편적으로 건물의 내부공간, 즉 매우 명확한 경계들을 전제로 잘 정의된 공간들에 관한 연구로 그 범위가 제한되어져 왔다. 따라서 건축, 도시, 또는 매우 광대한 의미에서의 환경디자인의 특권으로 알려져 있는 도시에 관한 쟁점을 그다지 자주 다루지 않는 편이라 할 수 있겠다. 그러나 극도로 고밀도화된 현대의 대도시들은 주요 지하 교통망을 중심으로 상업, 유흥, 업무시설 그리고 경우에 따라서는 주거단지에 까지 쉽게 연결되는 거대한양의 전이 실내공간들을 창출해내고 있다. 이것이 최근 홍콩의 건축가 게리 챙(Gary Chang)에 의해서 규정된 새로운 개념의 고밀도 도시 인테리어 랜드스케이프(interior landscape)인 것이다. 이러한 인테리어스케이프의 개념은 현대 도시의 모습 중에서 가장 흥미로운 개념들 중의하나라 할 수 있는데 다양한 요소들이 혼합된 그 특성은 이제 사회학, 건축, 인류학, 도시탐험, 인테리어 디자인, 도시 그리고 환경 디자인 등 다양한 분야에서 뜨거운 논쟁의 주제로 떠오르게 된 것이다. 이제 도시에 관한 연구는 더 이상 외부에서 내부로 진행되는 것이 아니고, 내부에서부터 출발되는 것이다. 극도로 밀집된 아시아의 대도시들은 이렇게 혼잡한 도시환경의 모든 요인들을 더 잘 이해할 수 있도록 다양하고 흥미로운 상황들을 제공해 주고 있다. 상업적 목적으로 건물 전체를 사용하는 수직적 전략이나 다양한 문화적 행태들은 도시 환경의 '혼잡성'을 그냥 참을만한 것이 아니라 오히려 그 도시만의 매력적 요소로 부각시켜 주는 것이다. 본 논문은 인테리어스케이프를 중심으로 진행되고 있는 다양한 이론적 논쟁들의 분석에 그 기초를 두고 있다. '장소성의 부재'의 개념, 혼잡의 문화, 공공공간의 사유화, 결절도시, 한계의 개념들을 분석하여 아시아 대도시들이 어떻게 이러한 쟁점들을 그들 자신만의 고유한 해결책으로 발전시키는지를 고찰하고자 한다. 본 논문의 목적은 서울을 사례분석 중 하나로 사용하여 인테리어 디자인 분야의 경계를 대도시로 확장하는 동시에 새로운 적용영역의 가능성을 탐구하는데 있다 하겠다.