• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.335-343
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• 2010

Steel corrosion in reinforced concrete (RC) structures is a critical problem to structural safety and many researches are being actively conducted on developing methods to maintain the required performance of the RC structures during their intended service lives. In this study, concrete mixture proportioning technique through genetic algorithm (GA) for RC structures under carbonation, which is considered to be serious in underground site and big cities, is investigated. For this, mixture proportions and diffusion coefficients of $CO_2$ from the previous researches were analyzed and fitness function for $CO_2$ diffusion coefficient was derived through regression analysis. This function based on the 12 experimental results consisted of 5 variables including water-cement ratio (W/C), cement content, sand percentage, coarse aggregate content per unit volume of concrete in unit, and relative humidity. Through genetic algorithm (GA) technique, simulated mixture proportions were proposed for 3 cases of verification and they showed reasonable results with less than relative error of 10%. Finally, assuming intended service life, different exposure conditions, design parameters, intended $CO_2$ diffusion coefficients, and cement contents were determined and related mixture proportions were simulated. This proposed technique is capable of suggesting reasonable mix proportions and can be modified based on experimental data which consider various mixing components like mineral admixtures.

• Archives of design research
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• v.12 no.4
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• pp.211-220
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• 1999

This study purposed more effective drawing process in practical lecture with students. Researched materials were constitution to a semester of presentation technique curriculum major in industrial design for freshman course. Students exert to entrance examination of university to get a good point in practical test. There did not have creative action in minds. But, design required concept of good idea sketch and creative technique. At study process should make correction a reform to sketch skill by repeat practicing with misunderstand drawing or imitative idea sketch. According to the practical test result & response revised lecture schedule. And then, I had survey to questionnaire paper for feedback by trial result. Besides, I was study to effect use the drawing materials for example, colored pencil, marker pastel. I think important to first use to way understanding materials and basic training. Design education be driven to new creative sketch skill. Design is the creative process to which brings ideas to reality.

• Wind and Structures
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• v.29 no.5
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• pp.323-337
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• 2019

Wind tunnel testing technique has been established as a powerful experimental method for predicting wind-induced loads on high-rise buildings. Accurate assessment of the design wind load combinations for tall buildings on the basis of wind tunnel tests is an extremely important and complicated issue. The traditional design practice for determining wind load combinations relies partly on subjective judgments and lacks a systematic and reliable method of evaluating critical load cases. This paper presents a novel optimization-based framework for determining wind tunnel derived load cases for the structural design of wind sensitive tall buildings. The peak factor is used to predict the expected maximum resultant responses from the correlated three-dimensional wind loads measured at each wind angle. An optimized convex hull is further developed to serve as the design envelope in which the peak values of the resultant responses at any azimuth angle are enclosed to represent the critical wind load cases. Furthermore, the appropriate number of load cases used for design purposes can be predicted based on a set of Pareto solutions. One 30-story building example is used to illustrate the effectiveness and practical application of the proposed optimization-based technique for the evaluation of peak resultant wind-induced load cases.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.1
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• pp.24-33
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• 2010

Design of a Pump Jet Propulsor (PJP) was undertaken for an underwater body with axisymmetric configuration using axial/low compressor design techniques supported by Computational Fluid Dynamics (CFD) analysis for performance prediction. Experimental evaluation of the PJP was earned out through experiments in a Wind Tunnel Facility (WTF) using momentum defect principle for propulsive performance prior to proceeding with extensive experimental evaluation in towing tank and cavitation tunnel. Experiments were particularly conducted with respect to Self Propulsion Point (SPP), residual torque and thrust characteristics over a range of vehicle advance ratio in order to ascertain whether sufficient thrust is developed at the design condition with least possible imbalance torque left out due to residual swirl in the slip stream. Pumpjet and body models were developed for the propulsion tests using Aluminum alloy forged material. Tests were conducted from 0 m/s to 30 m/s at four rotational speeds of the PJP. SPP was determined confirming the thrust development capability of PJP. Estimation of residual torque was carried out at SPP corresponding to speeds of 15, 20 and 25 m/s to examine the effectiveness of the stator. Estimation of thrust and residual torque was also carried out at wind speeds 0 and 6 m/s for PJP RPMs corresponding to self propulsion tests to study the propulsion characteristics during the launch of the vehicle m water where advance ratios are close to Zero. These results are essential to assess the thrust performance at very low advance ratios to accelerate the body and to control the body during initial stages. This technique has turned out to be very useful and economical method for quick assessment of overall performance of the propulsor and generation of exhaustive fluid dynamic data to validate CFD techniques employed.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1278-1280
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• 1995

A probe type fiber-optic sensing techique for electric current measurement is applied in this paper. The technique is based on the Faraday effect which meaning is that polarization state of light is rotated by magnetic field. In experiment, test wire is located at inside and outside of the probe to be measured. The experimental results prove not only linear property, but also polarization rotation property according to the distance from outside of probe.

• KCID journal
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• v.1 no.1
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• pp.44-53
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• 1994

Recently an introduction of pipe drainage systems has been employed. Especially the necessity of pipe drainage systems has been widely recognized at farms in the suburban districts, however, undertaking itself cannot overcome an experimental stage. Theref

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.152-156
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• 2007

We introduce the IP3102 which is developed by Interpion Semiconductor co. LTD. for the CFL ballaster. The IP3102 has thermal compensation function. In this paper, we present the temperature compensation design technique and its implementation in the IP3102. The experimental results is also presented in this paper.

• 전기의세계
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• v.31 no.2
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• pp.141-146
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• 1982

In this paper, surface acoustic wave (SAW) bandpass filter is designed using the Fourier series approach and the I$_{0}$-shin window function. And also we studied a method to realize SAW filter using the apodized ID transducer which was fabricated with aluminum metallization of about 1500 A over .deg. thickness on Y-cut Z-propagating LiNbO$_{3}$, crystal by photolithographic technique (lift-off method). Experimental results on SAW bandpass filter responses show good agreements with the theoretical characteristics.s.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.160.1-160
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• 2001

In this study, control technique of two types of automatic snowplow was experimentally investigated. One is a remote-controlled snowplow used for removing snow around houses, and the other is an autonomous snowplow for use in wide, open spaces such as a parking lot of a large-scale retail store. A commercially available snowplow was modified to enable remote control by the use of a personal handy-phone system. The autonomous controller utilizes a vision sensor that consists of a CCD video camera and a computer for image processing. In addition, design of a practical landmark was examined.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.311-315
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• 2006

This paper proposes 5 phase step motor drive system has high performance dynamics with micro step control has current controller. In this paper, analog current controller has been developed to minimize system size and cost. The validity of the proposed technique is verified through experimental results of position control robot.