• 콘크리트학회논문집
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• 제22권3호
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• pp.335-343
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• 2010

콘크리트 내부의 철근부식은 구조물의 안전성에 큰 영향을 주므로, 목표 내구수명동안 구 조물의 성능을 확보하려는 연구가 활발하게 진행되고 있다. 이 연구는 대도시나 지하구조물에서 중요하게 평가되는 탄산화에 대하여, 유전자 알고리즘을 적용한 콘크리트 배합기법에 대한 연구이다. 이를 위해, 배합인자에 따른 이산화탄소 확산계수를 문헌조사를 통하여 분석하였으며, 습도를 고려한 최적 함수식을 회귀분석을 통하여 도출하였다. 최적 함수식은 12개의 실험자료에 대하여, 물-시멘트비, 단위 시멘트량, 잔골재율, 단위 굵은골재량, 그리고 상대습도를 포함하도록 고려하였으며, 유전자 알고리즘을 통하여, 주어진 이산화탄소 확산계수에 대한 콘크리트 배합을 도출하였다. 3개의 배합에 대하여 검증한 결과, 10% 미만의 상대오차를 보이며 주어진 배합을 잘 추정하였다. 최종적으로 서로 다른 환경과 설계 제원을 가지는 콘크리트 구조물을 가정하여, 목표 확산계수와 단위 시멘트량을 계산하였으며, 이를 이용하여 배합을 추정하였다. 제안된 기법은 주어진 확산계수와 배합을 잘 추정하였으며, 다양한 배합인자 및 혼화재료가 고려된 실험 자료를 이용한다면 더욱 합리적인 배합 기법으로 발전할 것이다.

• 디자인학연구
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• 제12권4호
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• pp.211-220
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• 1999

대학 1학년 산업디자인 교과과정 내용에서 기초 표현과정과 표현방법을 실기시간에 효과적으로 표현전개하기 위해 한 학기동안의 강의내용을 기준으로 연구하였다. 신입생들의 실기표현은 대학입학 실기 시험에 대한 개념을 갖고 있으므로 대학 교과과정에서 적응을 위한 수정이 필요하다. 다시 말해, 대학 1학년에서 표현에 관한 과목은 학생들이 입시기간에 장시간 연습해온 표현방식에 젖어 있으므로, 창의적인 아이디어 발상과 전개를 위해서는 새로운 개념의 주입이 필요하다. 이를 바탕으로 이번 연구에서는 학생들의 표현 실기수업의 반응에 따라 실기내용을 일부 수정하였고, 거기에 따른 효과를 설문지로 측정해 보았다. 표현 재료는 4B연필, 마카, 파스텔, 색연필 등을 사용하여 조사하였고, 표현도구에 대해서도 학생들의 반응을 조사하였다. 그리하여 창의적인 발상을 주로 하는 디자인교육에서는 표현실기에서 이미 표현된 내용을 답습하는 것보다는 사물을 보고 표현 하든가 또는 자신이 구상한 Idea를 표현하도록 하는 것이 효과적이며, 표현도구에 대해서는 도구의 사용법에 대한 충분한 이해와 많은 기초 연습과정을 갖도록 하는 것이 바람직하다는 것을 알 수 있었다. 또한 기초과정이지만 Idea의 발상표현을 실기시간에 연습하여 창의적인 발상을 전제로 표현하는 것이, 처음의 효과가 즉시 나타나지 않지만 궁극적으로는 바람직함을 알 수 있었다. 그리고 앞으로는 컴퓨터 통신을 통한 새로운 교육과정이 표현실기부분에서 그 가능성을 제안하였다.

• Wind and Structures
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• 제29권5호
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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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• 제2권1호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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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.

• 한국관개배수논문집
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• 제1권1호
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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

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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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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• 제31권2호
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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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• 제어로봇시스템학회 2001년도 ICCAS
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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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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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.