• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.957-962
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• 2004

This paper deals with the free vibration analysis of beam-columns resting on Pasternak foundation by the Differential Quadrature Method. Based on the differential equation subjected to the boundary conditions, adopted from the open literature, which governs the free vibrations of such member, this equation is applied to the Differential Quadrature Method. For computing natural frequencies, the numerical procedures are developed by QR Algorithm, in which the Chebyshev-Gauss-Lobatto method is used for choosing the grid points. The numerical methods developed herein for computing natural frequencies are programmed in FORTRAN code, and all solutions obtained in this study are quite agreed with those in the open literature.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1507-1508
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• 2008

In this paper, we propose a direct robust adaptive backstepping speed controller for induction motors system. A robust adaptive backstepping controller is designed using high order neural networks(HONN), which avoids the singularity problem in adaptive nonlinear control. The stability of the resulting adaptive system with proposed adaptive controller is guaranteed by suitable choosing the design parameter and initial conditions. HONN are used to approximate most of uncertainties which are derived from unknown motor parameters, load torque disturbances and unknown nonlinearities. The applicability of the proposed scheme is tested simulation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.619-624
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• 2000

Longitudinal vibration of an axially moving material is investigated by using the assumed modes method. to circumvent a difficulty in choosing the comparison functions which satisfy the boundary conditions the assumed modes method is adopted by which equations of motion are discretized. Based on the discretized equations, the complex eigenvalue problem is solved and then the effects of the translating velocity on the natural frequencies and modes are analyzed.

• 한국정밀공학회지
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• 제15권8호
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• pp.116-125
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• 1998

In this paper, main target is to select parameters for prediction of tool wear and detection of tool fracture. The research about choosing parameter for prediction of tool wear is done by using force ratios. Also current sensor, tool-dynamometer, and accelerometer are used for researching detection method of tool fracture. Experiment is done using Taguchi's method in medium machining conditions. Parameter which is best for prediction of tool wear and detection of tool fracture by deviation analysis is selected. In this paper, tool wear means flank wear.

• 품질경영학회지
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• 제27권2호
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• pp.201-217
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• 1999

Industrial Measuring Instrument is a general name of equipments or tools for measuring and weighing. Inaccurate measuring instruments produce inferior goods in spite of excellent experts, good materials and wonderful equipments. Three characteristics are important for measuring instruments: choosing the proper instruments for measuring, using them properly and managing them to keep accuracy and precision. The purpose of this thesis is to develope the management standard for effective control of measuring instruments by analysing the problems and the management conditions of 100 PPM certified companies out of the domestic small and medium manufacturing industry, which steadily carry out quality control.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권12호
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• pp.5347-5360
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• 2016

In decode and forward relay systems, choosing the duplex mode is an important factor to the performance. To satisfy the performance requirement, self-interference must be mitigated for the full-duplex relay (FDR), and the resource efficiency must be increased for the half-duplex ratio (HDR). Therefore, if a wise scheme to consider these two factors exists, decode and forward relay systems are used more effectively. This study proposes a new duplex selection scheme for decode and forward relay systems. The proposed duplex selection scheme chooses the better duplex mode according to the channel statistical conditions with optimal power allocation. The simulation results show that the proposed duplex scheme with optimal power allocation has lower outage probability than the FDR and the HDR.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.84-91
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• 1998

A numerically stable technique to remove tile limitation in choosing a shift in the subspace iteration method with shift is presented. A major difficulty of the subspace iteration method with shift is that because of singularity problem, a shift close to an eigenvalue can not be used, resulting in slower convergence. This study selves the above singularity problem using side conditions without sacrifice of convergence. The method is always nonsingular even if a shiht is an eigenvalue itself. This is one of tile significant characteristics of the proposed method. The nonsingularity is proved analytically. The convergence of the proposed method is at least equal to that of the subspace iteration method with shift, and the operation counts of above two methods are almost the same when a large number of eigenpairs are required. To show the effectiveness of the proposed method, two numerical examples are considered

• 플랜트 저널
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• 제9권1호
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• pp.43-49
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• 2013

본 연구에서는 국내 P복합발전소에서 실제 운전 중인 순환수계통 수직펌프를 대상으로 고유진동수를 측정하고, 유체와 구조가 연성된 경우의 진동이론으로부터 고진동의 원인을 파악하였다. 현장 상황에 가장 적합하며 경제적인 공진방지 대책을 선정하여 수치해석을 통해 실효성을 미리 확인한 후 실제 시스템에 적용하는 실증시험을 실시하였다.

• 한국광학회지
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• 제12권6호
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• pp.489-495
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• 2001

난반사체를 이용한 다이오드 횡여기 Nd:YAG 레이저 헤드의 설계코드를 개발하여 레이저 결정 내 홉수된 빔의 균일성과 최대 레이저 출력을 갖는 설계요소의 조건에 관해 분석하고, 수치해석 방법으로 열렌즈 효과를 고려한 레이저 공진기의 레이저 출력을 계산하고 실험치와 비교 분석하였다. 1,080W의 여기광 출력에서 측정된 약 504 W의 레이저 출력은 열렌즈 효과를 고려하여 수치 해석적으로 계산된 레이저 출력과 레이저 공진기의 안정영역에서 거의 일치함을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.869-875
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• 2012

Because of the nature of wind, the output power of wind turbines fluctuates according to wind speed variation. Therefore, many countries have set up wind-turbine interconnection standards usually named as Grid-Code to regulate the output power of wind farms to improve power system reliability and power quality. This paper proposes three operation modes of wind farms such as maximum power point tracking (MPPT) mode, single wind turbine control mode and wind farm control mode to control the output power of wind turbines as well as overall wind farms. This paper also proposes an operation scheme of wind farm to alleviate power fluctuation of wind farm by choosing the appropriate control mode and coordinating multiple wind turbines in consideration of grid conditions. The performance of the proposed scheme is verified via simulation studies in PSCAD/EMTDC with doubly-fed induction generator (DFIG) based wind turbine models.