http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
차세대 항공 감시시스템(ADS-BES) 지상국 수신기 저잡음 증폭기 설계 및 구현
조주용,윤준철,박찬섭,박효달,강석엽,Cho, Ju-Yong,Yoon, Jun-Chul,Park, Chan-Sub,Park, Hyo-Dal,Kang, Suk-Youb 한국정보통신학회 2013 한국정보통신학회논문지 Vol.17 No.10
본 논문에서는 차세대 항공 감시시스템에 대하여 소개하고, 지상국 수신기 전단부 저잡음 증폭기 설계에 관하여 연구하였다. 국제 표준 문서와 기존 제품의 성능을 고려하여 수신감도, 신뢰성 등이 경쟁력 있게 전체 시스템을 링크 버짓 하였으며, 이에 적합한 저잡음 증폭기를 얻기 위해 이득, 이득 평탄도, 반사손실 등을 최적이 되도록 설계 규격을 결정하였다. 설계시 저전력, 저잡음, 고이득 특성에 적합한 바이어스 회로를 구성하였으며, 최적 설계 후 실시한 모의실험 결과로 이득은 16.24dB, 잡음지수는 0.36dB, 입출력 반사손실은 각각 -18dB와 -28dB, 주파수 안정도는 1.11을 얻었고, 제작 후 측정 결과는 이득 17dB, 잡음지수 0.51dB, 이득 평탄도 0.23dB, 입출력 반사손실은 각각 -18.28dB, -24.50dB로 전체 시스템 구성에 적합한 결과를 얻었다. This article introduces the next-generation air surveillance system and investigates how to design of front-end low noise amplifier of the ground station receiver. In consideration of the international standard documentation and the performance of existing products, the study conducts the link budget on the entire system so that it can be competitive in terms of receive sensitivity or reliability. To obtain a proper low noise amplifier, standards of design are decided so that such factors as gain, gain flatness, and reflective loss can be optimal. In its design, the bias circuit appropriate for the characteristics of low power, low noise, or high gain was built, and according to the results of the simulation conducted after the optimal design, its gain was 16.24dB, noise factor was 0.36dB, input-output reflective loss was -18dB and -28dB each, and frequency stability was 1.11. According to the results measured after the design, its gain was 17dB, noise factor was 0.51dB, gain flatness was 0.23dB, and input-output reflective loss was -18.28dB and -24.50dB each, so the results gained were suitable for building the overall system.
A SPECTRAL ANALYSIS METHOD FOR SPECTRAL ELEMENT MODELS
조주용(J. Cho),윤덕기(D. Yoon),황인선(I. Hwang),이우식(U. Lee) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월
In the literatures, the FFT-based SAM has been well applied to the computation of the steady-state responses of discrete dynamic systems. In this paper, a fast Fourier transforms (FFT)-based spectral analysis method (SAM) is proposed for the dynamic analysis of spectral element models subjected to the non-zero initial conditions. However, the FFT-based SAM has not yet been developed for the continuous systems represented by the spectral element model.
임의의 초기조건을 갖는 연속체계에 대한 스펙트럴 요소해석
조주용(Jooyong Cho),이우식(Usik Lee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
In this paper, a fast Fourier transforms (FFT)-based spectral element method (SEM) is proposed for the dynamic systems subjected to the non-zero arbitrary initial conditions. To evaluate the proposed SEM, the spectral element model for the simply supported Bernoulli-Euler beam is considered as an example problem. The accuracy of the proposed SEM is evaluated by comparing the dynamic responses obtained by SEM with the exact theoretical solutions.
비비례 진동감쇠를 갖는 선형 동역학계의 스펙트럴 해석법
조주용(Cho Jooyong),김성환(Kim Sunghwan),이우식(Lee Usik) 한국철도학회 2004 한국철도학회 학술발표대회논문집 Vol.- No.-
This paper introduces a fast Fourier transform (FFT)-based spectral analysis method for the transient responses as well as the steady-state responses of linear dynamic systems with non-proportional damping. The force vibration of a non-proportionally damped three-DOF system is considered as the illustrative numerical example. The proposed spectral analysis method is evaluated by comparing with the numerical solution obtained by the Runge-Kutta method.
A DAMAGE IDENTIFICATION METHOD FOR THIN CYLINDRICAL SHELLS
오혁진(H. Oh),조주용(J. Cho),이우식(U. Lee) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월
In this paper, a structural damage identification method (SDIM) is developed to identify the line crack-like directional damages generated within a cylindrical shell. First, the equations of motion for a damaged cylindrical shell are derived. Based on a theory of continuum damage mechanics, a small material volume containing a directional damage is represented by the effective orthotropic elastic stiffness, which is dependent of the size and the orientation of the damage with respect to the global coordinates. The present SDIM is then derived from the frequency response function (FRF) directly solved from the dynamic equations of the damaged cylindrical shell. In contrast with most existing SDIMs which require the modal parameters measured in both intact and damaged states, the present SDIM requires only the FRF-data measured in damaged state. By virtue of utilizing FRF-data, one may choose as many sets of excitation frequency and FRF measurement point as needed to acquire a sufficient number of equations for damage identification analysis. The numerically simulated damage identification tests are conducted to study the feasibility of the present SDIM.
이동하는 열탄성 보-평판의 진동에 대한 스펙트럴요소 해석
권경수(Kwon Kyung-Soo),조주용(Cho Joo-Yong),이우식(Lee U-Sik) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-
The axially moving thin beam-plates exposed to sudden thermal loadings may experience severe vibrations through the thermal shock process. For accurate prediction of the thermal shock-induced vibrations, this paper develops a spectral element model for axially moving thermoelastic beam-plates. The spectral element model which is represented by spectral element matrix is formulated from the frequency-dependent dynamic shape functions which satisfy the governing equations in the frequency-domain. Thus, when compared with the classical finite element model in which simple polynomial functions are used as the shape functions, the spectral element model can provide exact solution by treating a whole uniform structure member as a single finite element, regardless of its length.
구조감쇠가 고려된 스펙트럴요소 모델을 이용한 구조손상규명
김정수(Kim Jungsoo),조주용(Cho Jooyong),이우식(Lee Usik) 한국철도학회 2004 한국철도학회 학술발표대회논문집 Vol.- No.-
In this paper, a nonlinear structural damage identification algorithm is derived by taking into account the structurally damped spectral element model thinking over a real situation. The structural damage identification analyses are conducted by using the Newton-Raphson method. It is found that, in general Structural Damage Identification by using the Structurally Damped Spectral Element Model provides the same exact damage identification results when compared with the results obtained by the structurally undamped spectral model.