• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1068-1071
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• 2001

Recently, the minimum line width shows a tendancy to decrease and the multi-level to increase in semiconductor. Therefore, a planarization technique is needed, which chemical polishing(CMP) is considered as one of the most important process. CMP accomplishes a high polishing performance and a global planarization of high quality. But there are several defects in CMP such as microscratches, abrasive contaminations, and non-uniformity of polished wafer edges. Spin Etching can improve the defects of CMP. It uses abrasive-free chemical solution instead of slurry. Wafer rotates and chemical solution is simultaneously dispensed on a whole surface of the wafer. Thereby chemical reaction is occurred on the surface of wafer, material is removed. On this study, TEOS film is removed by CMP and Spin Etching, the results are estimated at a viewpoint of material removal rate(MRR) and within wafer non-uniformity(WIWNU).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.935-938
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• 1997

Recently, the minimum line width shows a tendency to decrease and the multi-level increase in semiconductor. Therefore, a planarization technique is needed and chemical mechanical polishing(CMP) is considered as one of the most suitable process. CMP accomplishes a high polishing performance and a global planarization of high quality. But there are several defects in CMP such as micro-scratches, abrasive contaminations, and non-uniformity of polished wafer edges. Wet etching include of Spin-etching can improve he defects of CMP. It uses abrasive-free chemical solution instead of slurry. On this study, ILD(INterlayer-Dielectric) was removed by CMP and wet-etching methods in order to investigate the superiority of wet etching mechanism. In the thin film wafer, the results were evaluated at a viewpoint of material removal rate(MRR) and within wafer non-uniformity(WIWNU). And pattern step height was also compared for planarization characteristics of the patterned wafer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.224-241
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• 2015

Multiview plus depth (MVD) videos are widely used in free-viewpoint TV systems. The best-known technique to determine depth information is based on stereo vision. In this paper, we propose a novel local stereo matching algorithm which is radiometric invariant. The key idea is to use a combined matching cost of intensity and gradient based similarity measure. In addition, we realize an adaptive cost aggregation scheme by constructing an adaptive support window for each pixel, which can solve the boundary and low texture problems. In the disparity refinement process, we propose a four-step post-processing technique to handle outliers and occlusions. Moreover, we conduct stereo reconstruction tests to verify the performance of the algorithm more intuitively. Experimental results show that the proposed method is effective and robust against local radiometric distortion. It has an average error of 5.93% on the Middlebury benchmark and is compatible to the state-of-art local methods.

• 한국정밀공학회지
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• 제29권3호
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• pp.261-265
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• 2012

In this study, glassy carbon was ground for lens core of glass mold press. Ultraprecision grinding process was applied for machining of core surfaces. During the process, brittle crack occurred because of hard-brittleness of glassy carbon. Author investigated optimized grinding conditions from the viewpoint of ductile mode grinding. Geometrical undeformed chip thickness was adopted for critical chip thickness that enables crack free surface. Machined cores are utilized for biaspheric glass lens fabrication and surfaces of lens were compared for verification of ground surface.

• Journal of information and communication convergence engineering
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• 제8권6호
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• pp.640-644
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• 2010

When we talk with hands-free in a car or noisy lobby, the performance of the echo canceller degrade because background noise added to echo caused by the distance from mouth to microphone is relatively long. It gives a reason for necessity of noise-robust and high convergence speed adaptive algorithm. And if acoustic echo canceller operated not perfectly, residual signal going through the echo canceller to far-end speaker remains residual echo, which degrade quality of talk. To solve this problem, post-processing needed to remove residual echo ones more. In this paper, we propose a new acoustic echo canceller, which has noise robust and high convergence speed, linked with linear predictor as a post-processor. By computer simulation, it is confirmed that the proposed algorithm shows better performance from acoustic interference cancellation (AIC) viewpoint.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.338-344
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• 2003

The seismic analysis method of spent fuel storage structures for PHWR plant is introduced in comparison with the method for PWR plant. Investigating the structural characteristics of the storage structures, the former is vertically stacked fuel storage trays, while the latter is welded honeycomb type structure. However, as both structures are submerged and free standing, the analysis methods to anticipate the seismic response of both structures are complicated. For the better estimation of actual seismic response, how to model the dynamic properties and the structural behaviour is the key issue. In this paper, the overall procedures of the seismic modelling and stability check for seismic sliding and overturning of the two different storage structures are discussed in the viewpoint of analysis reliability

• 대한의용생체공학회:의공학회지
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• 제20권4호
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• pp.485-493
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• 1999

Human can generate various posture and motion with nearly 350 muscle pairs. From the viewpoint of mechanisms, the human skeleton mechanism represents great kinematic and dynamical complexity. Physical and behavioral fidelity of human motion requires dynamically accurate modeling and controling. This paper describes a mathematical modeling, and dynamic simulation of human body. The human dynamic model is simplified as a rigid body consisting of 18 actuated degrees of freedom for the real time computation. Complex kinematic chain of human body is partitioned as 6 serial kinematic chains that is, left arm, right arm, support leg, free leg, body, and head. Modeling is developed based on Newton-Euler formulation. The validity of proposed dynamic model, which represents mathematically high order differential equation, is verified through the dynamic simulation.

• 한국초전도ㆍ저온공학회논문지
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• 제13권4호
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• pp.1-4
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• 2011

From the viewpoint of high field application, the mechanical and critical current properties of recently developed $REBa_2Cu_3O_y$ (RE123, RE: rare-earth) coated conductors are summarized. In addition, effective flux pinning mechanisms in RE123 are also introduced. As one of the examples for high field application, the upgrading of the 18 T cryogen-free superconducting magnet is shown. The large anisotropy of $J_c$ is a problem at low temperature and high magnetic field. The nanorod is considered as the useful methods to improve the anisotropy of $J_c$, although its efficiency becomes small at low temperature.

• 대한전기학회논문지
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• 제39권7호
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• pp.653-667
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• 1990

Superconductor is consolidated, for required current capacity, with proper numbers of basic strands which are multifilamentary composites. Althouth superconductors are perfectly loss-free under DC conditions of current and field, AC losses occur under time-varying condition of the current and field. The AC losses are a controllable inherent characteristics of supercondectors. The AC losses dependent on the changing rate of current and field can be reduced by reducing the filament diameter. On the other hand, finer filament results in manufacturing cost increase. Therefore, in this paper optimization technique of superconductor for SMES is proposed from the viewpoint of AC loss reduction and manufacturing cost increase. The case study shows that the technique can be effectively used for the design of superconductor for SMES, appreciating the influence of various parameters related to superconductor itself and operating condition of SMES. As a result of the case study, it is confirmed that the technique is more effective for the design of superconductor for SMES for electric power power system stabilization rather then SMES for energy storage.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.839-842
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• 2010

본 논문에서는 핸즈프리 전화통신를 위한 반향 및 잡음제거구조를 제안하다. 제안하는 구조는 주변 잡음이 많을 때 반향 경로 추정 성능이 우수한 개선된 AP 알고리즘을 적응 알고리즘으로 사용하고 비동시 통화구간에서 잔여반향신호를 선형예측하여 백색화시킨다. 컴퓨터 시뮬레이션을 통해 제안하는 방법이 AIC(acoustic interference cancellation) 측면에서 우수함을 보인다.