• 한국세라믹학회지
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• 제27권2호
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• pp.288-296
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• 1990

Parent glasses for the experiments were prepared to be ratio of Li2O : Al2O3 : SiO2=4.5 : 25 : 70.5 as basic components, and TiO2 and ZrO2 in the mixing ratio of 1 : 1 were added as the nucleating agents, whose contents were increased in each sample. DTA, XRD, SEM, IR were observed, and thermal expansion and transmissivities were measured for the crystallized samples under the controlled heat-treatments. The transformation temperatures and the dilatometric softening temperatures in thermal expansion curves, and also the exothermic peaks in differential thermo-analytical curves were shifted to lower temperature. The crystal phase deposited through the heat-treatment was identified as ${\beta}$-quartz solid solution with XRD and IR analysis. The crystalline phases in oopactified samples were ${\beta}$-spodumene coexiting with ${\beta}$-quartz solid solution. The samples having more than 3% nucleating agents were transparent. The crystallized grain sizes were ranged 0.05 to 0.1$\mu\textrm{m}$. The crystallized transparent samples were exceeded 85% in the transmissivity.

• 소음진동
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• 제4권2호
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• pp.137-146
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• 1994

An analytical method for linear free vibration of fully liquid-filled circular cylindrical shell with various boundary conditions is developed by the Fourier series expansion based on the Stokes' transformation. A set of modal displacement functions and their derivatives of a circular cylindrical shell is substituted into the Sanders' shell equations in order to explicitily represent the Fourier coefficients as functions of the end point displacements, forces, and moments. For the vibration relevant to the liquid motion, the velocity potential of liquid is assumed as a sum of linear combination of suitable harmonic functions in the axial directions. The unknown parameter of the velocity potential is selected to satisfy the boundary condition along the wetted shell surface. An explicit expression of the natural frequency equation can be obtained for any kind of classical boundary conditions. The natural frequencies of the liquid-filled cylindrical shells with the clamped-free, the clamped-clamped, and the simply supported-simply supported boundary conditions examined in the previous works, are obtained by the analytical method. The results are compared with the previous works, and excellent agreement is found for the natural frequencies of the shells.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.29-33
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• 2004

This paper presents ESPI system for the measurement of thermal expansion coefficient of STS430 up to 1,000$^{\circ}C$. Existing methods, strain gauge and moire have the limitation of contact to object and do not supply the coefficient up to 800$^{\circ}C$. There needs to measure the data up to 800$^{\circ}C$, because heat resistant materials have high melting temperature up to 1,000$^{\circ}C$. In previous studies related to thermal strain analysis, the quantitative results are not reported by ESPI at high temperature, yet. In-plane ESPI and vacuum chamber for the reduction of air turbulence and oxidation are designed for the measurement of the coefficient up to 1,000$^{\circ}C$and speckle correlation fringe pattern images are processed by commercial image filtering tool-smoothing, thinning and enhancement- to obtain quantitative results, which is compared with references data. The comparison shows two data are agreed within 4.1％ blow 600$^{\circ}C$ however, there is some difference up to 600$^{\circ}C$. Also, the incremental ratio of the coefficient is changed up to 800$^{\circ}C$. The reason is the phase transformation of STS430 probably begins at 800$^{\circ}C$.

• 복식
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• 제55권8호
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• pp.112-126
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• 2005

The purpose of this study is to analyze the aesthetic characteristics of 'movement' expression in modern fashion(1910-2004) based on a study of modern fine arts which adopted 'movement' element in their work. In this study the meaning of movement was defined as motion, changing position and transformation. Literature survey through books and research papers and demonstrative study with fashion collection photos were undertaken. The results wert as follows ; 1) Kinetic art, optical an, light kinetic art and technology art such as video and computer art have adopted 'movement' element in their work. 2) The plasticities of 'movement' fine arts were identified as mutual penetration, increase of visibility, use of non-traditional materials and dynamism. The internal meanings were identified as expansion of aesthetic experience and the concept of fine art, optimistic attitude on technology, spectator participation and integration of art and life. 3) The 'movement' expression in modern fashion was distinctively found in 1910s-20s(avant-garde fashion), 1960s (kinetic and optical art fashion) and mid 1990s to 2004 (techno-cyber fashion). 4) The plasticities of the 'movement' expression in modern fashion were identified as non-definition, use of non-traditional materials, dynamism. The internal meanings were identified as expansion of aesthetic experience and the concept of dress, optimistic attitude on technology, playfulness through participation. In conclusion, the expression of 'movement' in modern fashion has optimistic viewpoint on the development of modern society and is one of the interesting design points which will be pursued in the fellowing years.

• 한국기계가공학회지
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• 제7권2호
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• pp.72-77
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• 2008

In this study, we propose and develop PDMS-based modular actuators. The microactuator which looks like a small insect uses thermal expansion power of the PDMS (polydimethylsiloxane; $sylgar^{(R)}$ 184 silicone elastomer). The PDMS-based microactuator provides a large displacement due to a high thermal expansion coefficient (approximately 310ppm). The microacruator with 1mm length $350{\mu}m$ width is optimized by using a numerical analysis. The shape of the PDMS actuatoris variously designed. They are placed at several positions to find the optimal position that provides a high transformation ratio. The PDMS-based microactuators are fabricated using a conventional micromaching technique. The fabricated microactuator is heated using a hot-plate. The actuator displacement is measured as a function of temperature from $27^{\circ}C$ to $300^{\circ}C$. The experimental results are compared to the simulation result. When heating temperature up to $300^{\circ}C$ is applied to the PDMS actuator, each V-groove-shaped joint is actuated $30{\mu}$ mat $300^{\circ}C$. Anotherdesign of the microactuator has a maximum displacement of about 656mm.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.167-170
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• 2006

본 논문에서는 선형계수확장 기반의 웨이블릿 워터마킹 기법을 제안하였다. 워터마크의 안정성을 위하여 먼저 워터마크에 대하여 Amold 변환을 진행한다. 다음 워터마크와 원 영상에 웨이블릿 변환을 진행한다. 워터마크의 크기를 원 영상의 1/4 정도로 선택하였기 때문에 선형계수확장을 적용하여 워터마크를 원 영상 크기만큼 확대한다. 마지막으로 본 논문에서 제안한 웨이블릿 변환된 영상의 저주파대에 일정한 강도로 워터마크를 삽입한다. 워터마크의 추출 시에 기존 방법과 달리 F 노름(norm) 함수를 적용하여 추출된 워터마크와 원 워터마크의 유사도를 비교한다.

• 한국정밀공학회지
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• 제21권11호
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• pp.69-74
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• 2004

This paper presents ESPI system for the measurement of thermal expansion coefficient of STS430 up to 1,00$0^{\circ}C$ . Existing methods, strain gauge and moire have the limitation of contact to object and do not supply the coefficient up to 80$0^{\circ}C$ . There needs to measure the data up to 80$0^{\circ}C$, because heat resistant materials have high melting temperature up to 1,000'E In previous studies related to thermal strain analysis, the quantitative results have not reported by ESPI at high temperature, yet. In-plane ESPI and vacuum chamber for the reduction of air turbulence and oxidation are designed for the measurement of the coefficient up to 1,00$0^{\circ}C$ and speckle correlation fringe pattern images are processed by commercial image filtering tool-smoothing, thinning and enhancement- to obtain quantitative results, which is compared with references data. The comparison shows two data are agreed within 4.1% blow $600^{\circ}C$ however, there is some difference up to $600^{\circ}C$. Also, the incremental ratio of the coefficient is changed up to 80$0^{\circ}C$ . The reason is the phase transformation of STS430 probably begins at 80$0^{\circ}C$

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.90-94
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• 1986

This paper describes expansion of the state space pole assignment self-tuning control of SISO systems with system noise and abservation noise to that of MIMO systems. Resursive Prediction Error method is used for both parameter and state estimation in the block controllable canonical form. This simplifies the state feedback law by eliminating the online computation of transformation matrix.

• Communications for Statistical Applications and Methods
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• 제7권1호
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• pp.55-64
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• 2000

We propose a criterion for testing homogeneity of matrix intraclass covariance matrices of K multivariate normal populations, It is based on a variable transformation intended to propose and develop a likelihood ratio criterion that makes use of properties of eigen structures of the matrix intraclass covariance matrices. The criterion then leads to a simple test that uses an asymptotic distribution obtained from Box's (1949) theorem for the general asymptotic expansion of random variables.

• 대한화학회지
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• 제22권4호
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• pp.229-238
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• 1978

Spherical harmonic의 전개방법과 쌍극자모멘트의 행렬요소를 Mulliken의 overlap integral로 전환시키는 방법을 사용하여 쌍극자모멘트의 행렬요소를 계산하는 두가지 방법을 발전시켰다. 이 두 방법에 의하여 계산한 쌍극자모멘트행렬요소의 값은 서로 일치하였다.