• Journal of Biosystems Engineering
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• 제42권3호
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• pp.170-189
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• 2017

Purpose: This paper presents Raman chemical imaging technology for inspecting food and agricultural products. Methods The paper puts emphasis on introducing and demonstrating Raman imaging techniques for practical uses in food analysis. Results & Conclusions: The main topics include Raman scattering principles, Raman spectroscopy measurement techniques (e.g., backscattering Raman spectroscopy, transmission Raman spectroscopy, and spatially offset Raman spectroscopy), Raman image acquisition methods (i.e., point-scan, line-scan, and area-scan methods), Raman imaging instruments (e.g., excitation sources, wavelength separation devices, detectors, imaging systems, and calibration methods), and Raman image processing and analysis techniques (e.g., fluorescence correction, mixture analysis, target identification, spatial mapping, and quantitative analysis). Raman chemical imaging applications for food safety and quality evaluation are also reviewed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.135-137
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• 1994

In this paper, step response, speed, maximum frequency characteristics of 2-phase, 8-pole, HB type, prototype linear pulse motor(LPM) were investigated with the open loop control system(OLCS) being attached to the LPH. In this experiment, both 1-phase and 1-2 phase excitation types were adopted and microcomputer was used in deal with the data. The results point to some directions for the improvement of the open loop control system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1052-1055
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• 1997

The importance of dynamic stability of power system is increasing as the excitation system using static type are greatly enlarged. There are several types of PSS at Present, Elements of PSS consist of Notch filter, lead-lag filter, washout limiter which are variable. The existing power system has a difficulty in determining the optimal PSS parameters whenever PSS is installed. And it is recommended to retune PSS parameters periodically because system characteristics change due to aging. In this paper, intelligent PSS using fuzzy concept is introduced to get over difficulties mentioned above. The usefulness of fuzzy-type PSS was verified by applying FPSS to KEPCO power system. Generally, the voltage regulation deteriorates if conventional PSS is applied because supplementary signal is added into AVR summing point to damp Power oscillation. In this paper this problem is solved by AVR limiter and fuzzy members tuning.

• Selected Papers of The Society of Naval Architects of Korea
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• 제1권1호
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• pp.52-64
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• 1993

There exist many frame structural systems having some attachments reducible to damped spring-mass systems, concentracted masses and spring supports. For free and forced vibration analyses of such a system an analytical method based on the receptance method is presented. A framed structure having attachments is considered as a combined system composed of various Timoshenko beam and bar elements and the attachments. So, the vibration characteristics of the system are calculated by synthesizing receptances and Support Displacement Transfer Ratio (SDTR) of beam and bar elements In spectral and/or closed forms, and receptances of the attachments. In forced vibration analysis, arbitrary excitation forces at a point on the structure and displacement excitations at boundaries are considered. Numerical investigations are carried out for verification of the presented method, and the results show good accuracy and very high computational efficiency.

• 대한조선학회지
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• 제23권1호
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• pp.3-12
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• 1986

This paper investigates the static configurations and the dynamic behaviors of a single point mooring line. To obtain the static configuration and static tension distribution along the mooring line, including the effect of fluid nonlinear drag and the elasticity of the line, the Runge-Kutta fourth order numerical method was used. The relationship between the horizontal excursion and the horizontal restoring force component of the mooring line, which is very important to a mooring line design, and the effect of a subsurface buoy on the static configuration are presented. In nonlinear dynamic analysis including nonlinear fluid drag acting on the line and geometrical nonlinearity for large deflections, finite element method using updated Lagrangian was used to obtain the solution. In the case of upper end harmonic excitation of the mooring line, the dynamic motion and the tension were also presented.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.33-36
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• 1998

This paper is a study on a linear ultrasonic motor with a first longitudinal$(L_1)$ and fourth bending $(B_4)$ double-mode rectangular plate. The stator vibrator is composed of an elastic material plate and of a piezo-ceramic element having a motion by electrical excitation. Each strain vector differs by $90^{\circ}$ generate travelling wave with the elliptical displacement motion of a point on the surface. To magnify displacement of longitudinal direction in elliptical displacement motion, the motor has a mechanism of the.displacement enlargement. In this paper, the vibration shape of the stator is simulated using the finite element method. A detailed model considered of the piezoelectric effect and of the exact geometry of the stator is used to calculate the displacement. The position of displacement mechanism is decided by the maximum displacement.

• Structural Engineering and Mechanics
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• 제66권1호
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• pp.75-84
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• 2018

This study presents the reliability-based analysis of nonlinear structures using the analytical fragility curves excited by random earthquake loads. The stochastic method of ground motion simulation is combined with the random vibration theory to compute structural failure probability. The formulation of structural failure probability using random vibration theory, based on only the frequency information of the excitation, provides an important basis for structural analysis in places where there is a lack of sufficient recorded ground motions. The importance of frequency content of ground motions on probability of structural failure is studied for different levels of the nonlinear behavior of structures. The set of simulated ground motion for this study is based on the results of probabilistic seismic hazard analysis. It is demonstrated that the scenario events identified by the seismic risk differ from those obtained by the disaggregation of seismic hazard. The validity of the presented procedure is evaluated by Monte-Carlo simulation.

• 대한기계학회논문집B
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• 제33권2호
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• pp.124-132
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• 2009

Experiments have been performed to investigate fluid-elastic instability of tube bundles, subjected to twophase cross flow. Fluid-elastic is the most important vibration excitation mechanism for heat exchanger tube bundles subjected to the cross flow. The test section consists of cantilevered flexible cylinder(s) and rigid cylinders of normal square array. From a practical design point of view, fluid-elastic instability may be expressed simply in terms of dimensionless flow velocity and dimensionless mass-damping parameter. For dynamic instability of cylinder rows, added mass, damping and the threshold flow velocity are evaluated. The Fluid-elastic instability coefficient is calculated and then compared to existing results given for tube bundles in normal square array.

• 대한전기학회논문지:전력기술부문A
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• 제50권8호
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• pp.351-358
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• 2001

This paper deals with the PSS modeling of Ulchin N/P #1 as well as the generator and excitation system modeling by utilizing the recorded data from AVR step test, which has been performed by entering small voltage signal into the AVR summing point. In addition to it. two recorded results obtained from the AVR step test with PSS sunning and without PSS running have not only been compared each other on the time domain, but also they heve been analyzed with FFT analysis on the frequency domain; thus, the desirable effects of running PSS in Ulchin N/P #1 on power system have been explicitly confirmed. Finally, the derived PSS model parameters lead to good matches between simulation results and recorded data.

• 전기학회논문지
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• 제65권8호
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• pp.1400-1406
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• 2016

This paper presents a new adaptive converter control approach for electric motor systems whose voltage source is excited from photovoltaic (PV) power generators. First, an electric model is represented with dynamic states and output velocity of such DC motor systems. We propose a hybrid converter control law in which a state feedback control is applied as an auxiliary control framework. Moreover, control parameter estimation is derived to realize adaptive converter systems for effective control performance against stochastic PV power excitation in practice. We carry out stability analysis for such converter system by using a well-known eigenvalue theory. Lastly, numerical simulation is conducted to test reliability of the proposed converter control approach and prove its superiority in the control point of view.