• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.75-77
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• 1994

This paper presents a method of obtaining transmission network equivalents from the network's driving-point admittance characteristic. Proposed method is based on modal decomposition representation for the large-scale interconnected system. As a result, Norton-type of discrete-time filter model can be generated. It can reproduce the driving-point admittance characteristic of the network. Furthermore proposed model can be implemented into the EMTP in a direct manner. The simulation results with the full system representation and the developed equivalent system showed a good agreement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.78-80
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• 1994

Conventional methods for root finding of the algebraic equations are intrinsically synthetic division methods, i.e., which are the factorization in forms of $f(x)=(x-x_i)Q(x)$. So existing methods have some demerits such as deflation and root-polishing procedures. To overcome these defects a new powerful algorithm, namely circular arithmetic algorithm(CSM), was introduced and has been investigated about its fascinating properties. In this paper, we will propose a simple and effective method of getting the initial guesses for the roots of the equation. With this method the CSM can me all the root of equation with great efficiency.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.341-344
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But. using, transporting, and keeping of plastic component was happened post-deformation. As time goes by and temperature is changed, the post-deformation causes the problems of exterior design and performance. But, it is difficult to estimate the post-deformation by only thermal deformation analysis. Also, the estimation technique of the pest-deformation must be easily applied to product development and it should be reliable because development time of product is limited. In the paper. the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.

• International Journal of Aeronautical and Space Sciences
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• 제13권4호
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• pp.458-467
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• 2012

In this study, the linear viscoelastic response of a rectangular laminated plate is investigated. The viscoelastic properties, expressed by two basic spring-dashpot models, that is Kelvin and Maxwell models, is assumed in the range to investigate the influence of viscoelastic coefficients to mechanical behavior. In the present study, viscoelastic responses are performed for two popular equivalent single-layered theories, such as the first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT). Compliance and relaxation modulus of time-dependent viscoelastic behavior are approximately determined by Prony series. The constitutive equation for linear viscoelastic material as the Boltzmann superposition integral equation is simplified by the convolution theorem of Laplace transformation to avoid direct time integration as well as to improve both accuracy and computational efficiency. The viscoelastic responses of composite laminates in the real time domain are obtained by applying the inverse Laplace transformation. The numerical results of viscoelastic phenomena such as creep, cyclic creep and recovery creep are presented.

• Journal of Biosystems Engineering
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• 제31권2호
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• pp.102-107
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• 2006

Opening agricultural market progresses radically, reducing cost of high quality agricultural products becomes urgent. Aerial application using an agricultural helicopter helps precise and timely spraying and reduces labor intensity and pollution. The development of an agricultural helicopter was necessary for taking advantages of both technique and economy. In this study, as the first stage of developing an unmanned helicopter capable of 20kg payload, an engine was selected and a prototype transmission was designed for an agricultural helicopter. Prony type dynamo-meter was constructed, the engine was tested and then performance curve was obtained. The centrifugal clutch was engaged at the rotation speed of 3,500-4,000 rpm. Maximum power was expected at the engine speed of 5,900-6,200 rpm when adjusted at the optimal output. Based on the test results, the transmission was designed for driving main rotor shaft.

• 대한수의사회지
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• 제32권7호
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• pp.428-441
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• 1996

국제수역사무국(Office International des Epizooties;OIE)의 제64차 국제위원회 총회가 지난 5월 20일부터 24일까지 프랑스 파리시내 12rue de Prony에 소재하고 있는 국제수역사무국 본부에서 개최된 바 있다. 한편, 동회의기간중 세계수의사회(World Veterinary Association;WVA) 제 48차 총회 및 관련 각 위원회 또한 국제수역사무국 본부에서 개최된 바 있다. 국제수역사무국은 지난 1924년도에, 국제적 협력이 필요한 가축전염병의 병인과 방제대책에 관련된 실험 또는 연구업무의 증진과, 회원국 정부 및 각국 수의관련 부서로부터 가축질병과 방역대책에 관련된 전반적인 관심사항에 대한 모든 사실과 기록을 수집하여 주의를 환기시키고, 전염병 방역규정에 관한 국제적 협정초안을 검토하고 서명 당사국 정부에 시행 감독권한을 부여하거나 조정을 목적으로, 프랑스 정부의 주도하에 창립멤버 28개국 정부의 조인을 받아 국제협약에 의하여 설치되어 금년에 창립 72주년을 맞이하였으며, 금년 5월 현재의 정식가입 회원국수는 143개국이 되었다. 본편에서는, 제1장에서 국제수역사무국에 대한 연혁과 조직 기능, 역할과 업무활동, 향후 활동 발전방향 등에 대하여 간략히 해설하고, 제2장에서는 금년 (1996년도) 제64차 총회의 의사일정과 주요 협의사항, 각 위원회별 보고사항 등을 소개하고자 하며, 마지막으로 제3장에서는 금년 총회의 기술의제와 관련하여 우리나라의 보고사항을 기록해 두고자 한다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.193-197
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• 2003

Radar target identification can be achieved by using various radar signatures, such as one-dimensional(1-D) range profile, 2-D radar images, and 1-D or 2-D scattering centers on a target. In this letter, five 1-D scattering center extraction methods are discussed - TLS(Total Least Square)-Prony, Fast Root-MUSIC (Multiple Signal Classification), Matrix-Pencil, GEESE(GEneralized Eigenvalues utilizing Signal-subspace Eigenvalues), TLS-ESPRIT(Total Least Squares - Estimation of Signal Parameters via Rotational Invariance Technique), These methods are compared in the context of estimation accuracy as well as a computational efficiency using a noisy data. Finally these methods are applied to the target classification experiment with the measured data in the POSTECH compact range facility.

• KEPCO Journal on Electric Power and Energy
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• 제6권3호
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• pp.245-252
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• 2020

It is very important to evaluate on/off-line stability to operate the power system stably and economically. Until now, we have continuously secured the operation reliability of the power system through the evaluation of transient, voltage and small signal stability. This paper proposes that it is possible to operate in KWAMS by applying the multi-section analysis and subspace methods and verifying the reliability of the algorithms to directly estimate the dominant oscillation mode of the power system from the signal waveform acquired from the phasor measurement units. In addition, this paper shows that the dominant oscillation mode can be detected from real-time measurement data in power systems. Therefore, if we can monitor the state of the power system in real time, it is possible to avoid a large-scale power outage by knowing the possibility of the power system accident in advance.

• Structural Engineering and Mechanics
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• 제88권6호
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• pp.589-598
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• 2023

This article addresses the quasi-static analysis of time-dependent honeycomb sandwich plates with various geometrical properties based on the bending analysis of elastic honeycomb sandwich plates employing a time function with three unknown coefficients. The novel point of the developed method is that the responses of viscoelastic honeycomb sandwich plates under static transversal loads are clearly formulated in the space and time domains with very low computational costs. The mechanical properties of the sandwich plates are supposed to be elastic for the faces and viscoelastic honeycomb cells for the core. The Boltzmann superposition integral with the constant bulk modulus is used for modeling the viscoelastic material. The shear effect is expressed using the first-order shear deformation theory. The displacement field is predicted by the product of a determinate geometrical function and an indeterminate time function. The simple HP cloud mesh-free method is utilized for discretizing the equations in the space domain. Two coefficients of the time function are extracted by answering the equilibrium equation at two asymptotic times. And the last coefficient is easily determined by solving the first-order linear equation. Numerical results are presented to consider the effects of geometrical properties on the displacement history of viscoelastic honeycomb sandwich plates.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.596-604
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• 2016

In this study, we used a stochastic approach for guaranteeing the reliability and robustness of the performance with regard to the design of polymer components, while taking into consideration the degradation properties and operating conditions in automobiles. Creep and tensile tests were performed for obtaining degradation properties. The Prony series, which described the viscoelastic models, were calculated to use the creep data by the Maxwell fluid model. We obtained the stress data from the frequency response analysis of the polymer components while considering the degradation properties. Limit state functions are generated by using these data. Reliability assessments are conducted under the variation of the degradation properties and area of frequency at peak response. For this study, the input parameters are assumed to be a normal distribution, and the reliability under the yield stress criteria is evaluated by using the Monte Carlo Simulation. As a result, the reliabilities, according to the three types of polymer materials in automotive components, are compared to each other and suggested the applicable possibility of polymeric materials in automobiles.