• 한국통신학회논문지
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• 제8권4호
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• pp.151-155
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• 1983

본 논문에서는 탄성 표면과 자연특성을 응용하여 외부 여과기와 동조회로를 사용하지 않고 2개의 출력 구성하여 발전 주파수를 가변할 수 있는 새로운 탄성표면과 발진기에 관하여 연구하였다. 실험결과 탄성표면과 발진기의 주파수 결정소자로서 사용된 AT-cut수정의 온도 특성은 안정하였으며 가변 주파수의 범위는 좁으나 탄성표면과 소자의 설계에 따라 그 가변범위를 확대할 수 있음을 알 수 있었고 또한 높은 주파수내에서 기본파 발진의 안정성을 확인하였다.

• 방송공학회논문지
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• 제13권1호
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• pp.128-136
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• 2008

본 논문에서는 인접 블록 움직임 벡터의 통계적 특성을 이용한 가변 탐색 스텝의 고속 움직임 추정 기법에 대해 제안한다. 인접 블록 움직임 벡터들 사이의 상관 관계를 이용하여 움직임 추정을 위한 탐색 영역을 적응적으로 결정하였으며, 이를 통해 불필요한 탐색 지점 수를 제거할 수 있었다. 이와 같이 결정된 탐색 영역을 기반으로 가변 탐색 스텝 움직임 추정을 적용하였으며 움직임 추정을 위한 연산량을 줄일 수 있었다. 실험 결과를 통해 제안 방식이 H.264 JM의 고속 전 대역 spiral 탐색 기법과 기타 고속 움직임 추정 방식과 비교하여 부호화 성능의 저하 없이 움직임 추정을 위한 탐색 지점 수 및 연산 량이 급격히 감소됨을 확인할 수 있었다.

• 한국전자파학회논문지
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• 제19권3호
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• pp.311-320
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• 2008

본 논문에서는 종래의 접지된 능동 인덕터 구조와 궤환 가변 LC-공진기를 이용한 새로운 가변 능동 인덕터를 제안하였다. 접지된 능동 인덕터는 자이레이터-C 구조로 구현되며, 가변 LC-공진기는 낮은 Q 지수를 갖는 나선 인덕터와 바렉터로 이루어진다. 가변 LC-공진기는 트랜지스터의 기생 커패시턴스에 의한 Q 지수의 감소를 보상하며, LC-공진기의 공진 주파수 조절에 의해 높은 Q 지수를 갖는 주파수 대역을 가변할 수 있다. 매그나칩 $0.18{\mu}m$ 공정을 이용하여 제작된 가변 능동 인덕터는 $4.66{\sim}5.45GHz$ 대역에서 바랙터 제어 전압 조정에 의해 높은 Q 지수를 갖는 주파수를 조정할 수 있으며, 동자 대역에서 50 이상의 Q 지수를 제공한다. 또한, 바렉터 제어전압 조정으로 5.1 GHz에서 $4.12{\sim}5.97nH$의 가변 인덕턴스 값을 얻을 수 있었다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1993년도 학술논문발표회 논문집 제12권 1호
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• pp.88-92
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• 1993

In speech signal processing, it is necessary to detect exactly the pitch. The algorithms of pitch extraction which have been proposed until now are difficult to detect pitches over wide range speech signals. Thus we propose a new algorithm which uses the G-peak extraction to do it. It is the method that finds the most MZI(maximum zero-crossing interval) at each frame and convolve it with speech signal ; this is the same with passing speech signals to variable LPF. Finally we obtained the pitch, improve the accuracy of pitch detection and extract it with the high speed.

• 전자공학회논문지A
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• 제29A권2호
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• pp.33-40
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• 1992

The design method of signal delay line system using indirect frequency synthesizer is presented. The variable signal delay line system with 2[nsec] step of delay time at center frequency 60[MHz], bandwidth 500[KHz] and range 5.24-5.81[x10S0-6Tsec] is designed and fabricated. The results were met with good characteristics to be variable delay time of average 2.01[nsec] per step.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.183-185
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• 2002

Heavy ion and proton therapy necessitate range weeks, which are time consuming. Three types of variable compensator, membrane type liquid variable compensator, are proposed by some of the authors to overcome the difficulties, by those arbitrarily thickness distribution of compensator obtained from treatment planning is created at the site of treatment. None of the ideas, however, is yet realized. In this research, we are trying to construct prototype membrane-type liquid variable compensator. This variable compensator partitions air and liquid with elasticity membrane and changes the surface of the elasticity membrane with the thread. The air and oil move through holes to and from the out of beam side of two boxes in which they are contained. The boxes are made of Plexiglas(PMMA), the thread which is made of nylon, the elasticity film which is made from latex for the moment.

• 정보처리학회논문지A
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• 제8A권1호
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• pp.56-62
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• 2001

This paper presents a neural network based variable structure control scheme for nonlinear systems. In this scheme, a set of local variable structure control laws are designed on the basis of the linear models about preselected representative points which cover the range of the system operation of interest. From the combination of the set of local variable structure control laws, neural networks infer the approximate control input in between the operating points. The neural network based variable structure control alleviates the effects of model uncertainties, which cannot be compensated by the control techniques using feedback linearization. It also relaxes the discontinuity in the system’s behavior that appears when the control schemes based on the family of the linear models are applied to nonlinear systems. Simulation results of a ball and beam system, to which feedback linearization cannot be applied, demonstrate the feasibility of the proposed method.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.167-173
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• 2003

For the measurement of mass flow rate at a wide range of operation conditions, it is required that the critical nozzle gas different diameters, since the mass flow rate through the critical nozzle depends on the nozzle supply conditions and the nozzle throat diameter. In the present study, both computational and experimental investigations are performed to explore the variable critical nozzle. Computational work using the 2-dimensional, axisymmetric, compressible Navier-Stokes equations are carried out to simulate the gas flow through variable critical nozzle. In experimnet, a cylinder with several different diameters is inserted into the critical nozzle to vary the nozzle throat diameter. Computational results are compared with the experimented ones. The computed results are in close agreement with experiment. It is found that the displacement and momentum thickness of variable critical nozzle are given as a function of Reynolds numbers. The discharge coefficient of the variable critical nozzle is predicted using an empirical equation.

• 전기학회논문지
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• 제56권10호
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• pp.1807-1813
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• 2007

This paper deals with extending the variable natural oscillation frequency range of an active integrated FET oscillator. In this paper, we conform experimentally that the variable range of the natural oscillation frequency is expanded about three times in the oscillator controlled by the varactor diode. When the frequency difference is given to the oscillators in the two element antenna system, phase difference appeared between the oscillators. The 2-, 3-, 4-, 5-element patch antenna arrays are composed for the beam scanning experiments. All the above patch antennas show good phased array characteristics. The range of the scanning angle is about $30^{\circ}$, and the radiation power is gradually increased from $50{\mu}W\;to\;200{\mu}W$. The radiation patterns we sharpened as the number of elements is increased.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2002년도 춘계학술대회 논문집
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• pp.190-194
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• 2002

Human uses sight, tactile sense to evaluate Total Hand Value(FUUAI) of textile fabrics. Tactile sense is important factor which decided the Total Hand Value of a textile fabric. When human feels the FUUAI, physical and physiological phenomena are occurred in finger. We first found out physical variable that is happened in fingertip when human is feeling the FUUAI. Such physical variable means characteristic of action tactual motion of finger such as moving range, tactile time, moved distance, speed of finger and applied force by finger. We study the relationship between action tactual motion and the ability in which the human distinguishes the textile fabric. As a result, we could know the characteristics of the tactual motion of fingertip to get high distinguishable ability. The characteristics were different in men and women respectively. In the case of man, touched time and moving range influenced to distinguish, and moving range, and the moving speed of finger influenced, in woman's case.