• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.164-168
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• 1995

As nation's infrastructure is getting old, nondestructive evaluation of existing structures and construction quality control are getting important. In this paper non-destructive evaluations of concrete members using impact echo and SASW methods are introduced. Both techniques are based on the stress wave propagations. Experimental tests were performed using beam type concrete member where voids and cracks are included. Within reasonable accuracy, void locations were detected using impact echo method and the dynamic modulus of concrete were measured using SASW method. Both NDT methods showed a feasibility for the implementation into quality evaluaton of concrete members in practice

• Wind and Structures
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• v.4 no.2
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• pp.101-118
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• 2001

This paper reports the field measurements concerning pressure equalization of rainscreen facades carried out at the Technical University of Eindhoven (TUE) in the Netherlands. The field facility including the details of test panel, meteorological tower, instrumentation, data collection and analysis is presented. Results of investigations into cavity response for various leakage and venting configurations are discussed. Frequency domain techniques have been utilized to show the influence of wind as well as facade characteristics on the pressure equalization performance. Further, this paper presents an early attempt to synthesize the experimental results into existing building codes.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.259-276
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• 2016

Historically the UK has been a pioneer and early adopter of experimental investigation techniques on new and operation structures, a technology that would now be descried as 'structural health monitoring' (SHM), yet few of these investigations have been enduring or carried out on the long span or tall structures that feature in flagship SHM applications in the Far East.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1101-1104
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• 1999

This paper performed a comparative study on contour tracing based thinning algorithms. These algorithms are widely used for extracting skeleton due to its superiority to other techniques in processing speed to perform comparison. We selected general eight images consisted of fingerprints, characters, and figures. According to experimental results, we compared each algorithm in performance and ability made skeleton.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.197-200
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• 2000

In this paper, we present a novel methodology for a wideband HTS antenna of finite length placed on a dielectric substrate. A methodology used in this work is based on a moment-method techniques with Green function singularity when the field point is in the source triangle. The designed resonance frequency of our HTS antenna is 11.85 GHz. The return loss is -26 dB. The bandwidth obtained is a significant 10.6 %. Experimental measurements for a HTS antenna designed in X-band are shown to agree well with the simulated prediction.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.17-20
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• 2000

Usually, in many applications, high frequency resonant inverters are used, and the PAM(Pulse Amplitude Modulation), PFM(Pulse Frequency Modulation) or PWM(Pulse Width Modulation) techniques are used to control the output power of resonant inverters. In this paper, a new switching scheme is proposed as a PWM control method. With the proposed method, it can be obtained that unity output displacement factor under the variable resonant frequency. The detail algorithm of the proposed PWM switching scheme and its charicteristics are discussed. And the validity of the proposed method is confirmed with the experimental results.

• Journal of Power Electronics
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• v.9 no.2
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• pp.288-299
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• 2009

This paper proposes a feedback linearization control scheme of AC/DC PWM converters with LCL input filters using no damping resisters. Feedback linearization techniques use a transformation from nonlinear system models into equivalent linear models in a simpler form. The feedback linearization scheme in this work has cascade structures unlike usual feedback linearization, therefore it has an advantage that it is possible to limit the capacitor current to a certain level. The performance of the proposed controller is validated with simulation and experimental results.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.77-78
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• 2012

To predict combustion instability in actual full-scale combustion chamber of rocket engines, air-injection test is proposed with scaling techniques. From the data, damping factors have been obtained as a function of hydraulic parameter and the data give us instability map. Two instability regions are presented and it is found that they coincide reasonably with them from hot-fire test with full-scale flow rates. Accordingly, the proposed approach can be applied cost-effectively to stability rating of jet injectors when mixing of fuel and oxidizer jets is the dominant process in instability triggering.

• Journal of KSNVE
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• v.10 no.6
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• pp.971-976
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• 2000

High level random vibration environments induced while launching of spacecraft can damage sensitive electronic equipment, unless the equipment is properly packaged. Thus careful consideration on the launch environment, especially for high level random vibration, is required in the design stage of electronic equipment of spacecraft. This paper describes the development process of Solar Array Regulator for KOMPAT-2, which is designed and tested by Korean engineers. Both analytical and experimental techniques are introduced in this paper.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.6
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• pp.368-375
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• 1988

This paper is concerned with the design of the optimal gains of the controller in the speed control system for the induction motor controlled by the microprocessor. The system is modelled with the discrete-time state equation, considering the time delay, for the facility of the optimization techniques. Introducing the conjugate gradient descent method, as the optimization technique, are derived the optimal gains, the gains which give the best transient characteristics. At the optimal gains obtained, the theoretcal transient responses are verified by experimental ones on a 5HP induction motor drive system.