• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.251-253
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• 2008

This research combines LED display System with a module of solar cell which transforms solar energy to electrical energy. In order to simplify the installation and the movement of LED Display System, the system removed the conventional power distribution is developed, and that improves the advertising effect of LED Display System.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.170-180
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• 1995

A parallel crack in bonded dissimilar orthotropic planes under out-of-plane loading is analyzed. The problem is formulated by Fourier integral transforms, and reduced to a pair of dual integral equations. By solving the integral equations, the asymptotic stress and displacement fields near the crack tip are determined in closed form, from which the stress intensity factor and energy release rate are obtained. Discontinuity in the stress intensity factor as the distance ratio h/a of the parallel crack approaches zero is found, while the energy releas rate is shown to be continuous at h/a = 0. This information can immediately be used to generate the stress intensity factor for the parallel crack near the interface. By employing "the maximum energy release rate criterion", it could be shown in the case of no existing crack initially that the parallel crack is formed far from the interface for the more compliant material, while it is formed close to the interface for the stiffer material. material.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.377-380
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• 2002

This paper presents the results of a study investigating methods of interpretation of wave directionality based on wavelet transforms. Two-dimensional discrete wavelet was used for the analysis. The proposed scheme utilizes a single frame of ocean waves to detect their directionality. This fact is striking considering the fact that traditional methods require long time histories of ocean wave elevation measured at various locations. The developed schemes were applied to the data generated from numerical simulations and video images to test the efficiency of the proposed scheme in detecting the directionality of ocean waves.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.163-167
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• 2007

We propose an XML document storage system, called XDMS (XML Document Management System), by using an object-relational DBMS. XDMS generates object database schema from XML Schema and stores the XML documents in an object-relational database. SAX parser is used for understanding the structure of the XML documents, and XDMS transforms the documents into objects in the database. Experiment shows that object-relational databases provide more efficient storage and query model compared with relational databases.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.266-268
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• 2012

영상신호의 보간을 위해서 다양한 기법이 제안되었고 H.264와 HEVC 동영상 부호화 표준 기법에서는 움직임 추정의 정확성을 높이기 위해서 1/2과 1/4 위치의 부화소 보간을 위한 보간 필터를 사용한다. 본 논문에서는 lapped transform을 이용하여 1/2과 1/4 위치의 부화소 보간을 위한 효율적인 기법을 제안한다. 제안하는 기법은 영상의 크기 변환과 보간과의 관계를 이용하여 부화소를 효율적으로 보간하는 기법이다. 제안하는 기법 및 H.264, HEVC에서 사용되는 보간 필터를 사용하여 영상을 보간한 경우의 성능을 비교한다.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.318-320
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• 1999

Electric motor transforms electric power into mechanical power. It is important to increase efficiency of motor to save energy and to decrease operating cost. In this paper, some parameters and losses of high-efficiency induction motor and standard induction motor are measured by blocked-rotor test and no-load test. Operational parameters of high-efficiency induction motor that are compared with those of standard motor.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.335-337
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• 2003

The protection against transient instability and consequent out-of-step condition is a major concern for the utility. The unstable system may cause serious damage to system elements such as generators and transmission lines. Therefore, out-of-step detection is essential to operate a system safely. This paper presents the Out-of-Step detection algorithm using voltage frequency variation. The digital filters based on Discrete Fourier Transforms (DFT) to calculate the frequency of a sinusoid voltage are used, and the generator angle is estimated using the variation of the calculated voltage frequency. The proposed out-of-step algorithm is based on the assessment of a transient stability using equal area criterion. The proposed out-of-step algorithm is verified and tested by using EMTP MODELS.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.138-142
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• 1996

The transition metal carbonylate, PPN+(${\eta}^5-MeCp)Mn(CO)_2Cl^-$ undergoes a novel ligand substitution reaction with PR3 (R=Me, Et, OEt, $C_6H_5$ in THF at elevated temperatures (40 $^{\circ}C$ up to 60 $^{\circ}C)$ under the pseudo-first-order reaction conditions (usually 20-fold excess of PR3 with respect to metal carbonylate concentrations) where chloride is displaced by PR3. The reaction follows overall first order dependence on [(${\eta}^5-MeCp)Mn(CO)_2Cl^-$]; however, the negative entropy changes of activation (${\Delta}S^{\neq}$=-19.3 e.u. for $P(OEt)_3$; ${\Delta}S^{\neq}$=-16.4 e.u. for $PPh_3$) suggest the existence of the intermediate, ((η3-MeCp)Mn(CO)2(THF)Cl-, which eventually transforms to the product (${\eta}^5-MeCp)Mn(CO)_2(PR_3)$.

• Bulletin of the Korean Chemical Society
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• v.5 no.4
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• pp.149-153
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• 1984

Reactions of $MoOCl_5^{2-}$ with ${\alpha}_2-[P_2W_{17}O_{61}]^{10-}$ have been studied spectrophotometrically and several complexes have been identified. The transient species initially formed is probably $[Mo_2O_4(P_2W_{17}O_{6l})_2]^{18-}$. At $pH {\le} 3$the visible spectrum changes gradually, indicating formation of a transient isomer of $[P-2Mo^VW_{17}O_{62}]^{7-}$, which again transforms into the stable isomer. The transient isomer absorbs light much more strongly than the stable isomer in the visible range. At $pH > 3 [P_2W^VW_{16}O_{61}]^{11-}$ is formed probably via the transient isomer of $[P_2Mo^VW_{17}O_{61}]^{7-}$.

• Bulletin of the Korean Mathematical Society
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• v.56 no.5
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• pp.1117-1127
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• 2019

Let ${\mathcal{L}}_2=(-{\Delta})^2+V^2$ be the $Schr{\ddot{o}}dinger$ type operator, where nonnegative potential V belongs to the reverse $H{\ddot{o}}lder$ class $RH_s$, s > n/2. In this paper, we consider the operator $T_{{\alpha},{\beta}}=V^{2{\alpha}}{\mathcal{L}}^{-{\beta}}_2$ and its conjugate $T^*_{{\alpha},{\beta}}$, where $0<{\alpha}{\leq}{\beta}{\leq}1$. We establish the $(L^p,\;L^q)$-boundedness of operator $T_{{\alpha},{\beta}}$ and $T^*_{{\alpha},{\beta}}$, respectively, we also show that $T_{{\alpha},{\beta}}$ is bounded from Hardy type space $H^1_{L_2}({\mathbb{R}}^n)$ into $L^{p_2}({\mathbb{R}}^n)$ and $T^*_{{\alpha},{\beta}}$ is bounded from $L^{p_1}({\mathbb{R}}^n)$ into BMO type space $BMO_{{\mathcal{L}}1}({\mathbb{R}}^n)$, where $p_1={\frac{n}{4({\beta}-{\alpha})}}$, $p_2={\frac{n}{n-4({\beta}-{\alpha})}}$.