• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.65-67
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• 2018

최근 무선전력분야에서도 고전력 시스템에 대한 적용 연구가 활발해지고 있다. 이러한 시스템 설계는 시뮬레이션 소프트웨어 프로그램으로 설계를 할 수는 있지만, 실험 검증을 위해서는 고전력 수전 설비 및 고가의 측정 설비가 필요하고, 하드웨어를 제작하려면 많은 시간과 비용이 필요하다. 본 논문은 척도변환을 이용하여 코일 형상을 포함한 하드웨어 구조는 최대한 유지하고 소자정격과 입력 전력을 축소하여 시스템 성능을 사전 평가하는 방법을 제안한다. 도출된 이론을 바탕으로 150W급 무선전력 전송 시스템을 대상으로 15W급으로 10 : 1 비로 축소 적용 가능함을 시뮬레이션 실험으로 검증한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.450-461
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• 1998

The spatial distribution of multipath fading using miniaturized experimental setup was analyzed. The spatial Fourier transform was carried out for the analysis of the period of fading and we could find out spatial frequency component of fading. Thus the analysis using this method shows the validity of miniaturized experimental setup. The miniaturized experimental setup was made by 5 times reducing of the real size. The simulation was performed at 2 GHz and the measurement was carried out at 10 GHz. Automatic antenna moving system was made for exact measurement of the multipath fading. Both simulated and measured results in miniaturized experimental setup were shown by electric field distribution and spatial frequency density distribution curves.

• Tunnel and Underground Space
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• v.14 no.1
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• pp.54-68
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• 2004

In this study, scaled model tests were performed on blasting demolition of reinforced concrete structures and the experimental results were analyzed in comparison with the results of numerical analysis. The tests were designed to induce a progressive collapse, and physical properties of the scaled model were determined using scale factors obtained ken dimension analysis. The scaled model structure was made of a mixture of plaster, sand and water at the ratio determined to yield the best scaled-down strength. Lead wire was used as a substitute for reinforcing bars. The scaled length was at the ratio of 1/10. Selecting the material and scaled factors was aimed at obtaining appropriately scaled-down strength. PFC2D (Particle Flow Code 2-Dimension) employing DEM (Distinct Element Method) was used for the numerical analysis. Blasting demolition of scaled 3-D plain concrete laymen structure was filmed and compared to results of numerical simulation. Despite the limits of 2-D simulation the resulting demolition behaviors were similar to each other. Based on the above experimental results in combination with bending test results of RC beam, numerical analysis was carried out to determine the blasting sequence and delay times. Scaled model test of RC structure resulted in remarkably similar collapse with the numerical results up to 900㎳ (mili-second).

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.11a
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• pp.258-265
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• 2002

베이지안망은 기존의 방법에 비해 불확실한 상황에서도 지식을 표현하고 결론을 추론하는데 유용한 것으로 알려져 있다. 본 논문에서는 대표적인 베이지안망 분류기들을 제시하고, 동일 임상데이터에 대해 서로 다른 유형별 베이지안망 분류기들을 학습하였다. 베이지안망을 적용할 때 변수의 수가 많아짐에 따라 베이지안망의 구조를 학습하는데 탐색공간이 넓어져 어려움이 있다. 본 연구에서는 이런 탐색공간을 효율적으로 줄이기 위하여 클래스 노드의 Markov blanket에 속한 특징들로 집합을 축소하는 것을 제안하고, 실험을 통해 이 특징 축소방법이 베이지안망 분류기들의 성능을 높여 줄 수 있는지 알아보았다. 분류기들의 성능에서는 축소한 특징집합으로부터 얻은 베이지안망으로 확장한 나이브 베이지안망 분류기가 가장 우수한 정확도를 가짐을 실험을 통해 알 수 있었다.

• Explosives and Blasting
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• v.22 no.1
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• pp.33-43
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• 2004

In this study, a comparison was made between the resulting behaviors of scaled model test and particle flow analysis for blasting demolition of a reinforced concrete structure. For the test and analysis, a progressive failure of a five-story structure was considered. The dimension analysis was carried out to properly scale down the real structure into the laboratory size. The test model was made of the mixture of gypsum, sand and water along with soldering lead to analogy reinforcing steel bars. The ratio of mixing components was chosen to best represent the scaled down strength and deformation modulus. The columns and girders of the structure were precasted in the laboratory and assembled right before the blasting test. The numerical analysis of the blasting demolition was carried out using PFC2D (Particle Flow Analysis 2-Dimension by Itasca). The results of the blasting of concrete lahmen structure showed roughly identical demolition behavior between scaled model test and numerical test. For the blasting of the reinforced concrete structure, the results were more identical and closer to the real demolition behavior, since the demolition behavior was better represented in this case due to the increased tensile strength of the component.

• Tunnel and Underground Space
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• v.26 no.6
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• pp.508-515
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• 2016

In this study, we compared the stability of the pillars by using room and pillar mining method with the four models with different stiffness and pillar overlap ratio. The experimental models consist of two plaster models (overlap ratio 0%, 100%) and two cement models(overlap ratio 0%, 100%). The soft and hard rocks are modeled by plaster and cement models respectively. In these experiments, the model materials with strength values reflecting the calculated scaled factors not been used, so it is not a true scaled model test that reproduces in situ state in the laboratory. Experimental results show that the different overlap ratio pillars are one of the factors that can affect the stability of the mine.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.2
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• pp.39-48
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• 1997

New form of base isolators made of steel spring coated with both natural and artficial rubber were manufactured and tested for material properties. Shaking table experiments were performed using a model structure attached with the bearings. The model structure used in the test is a 1/4 scaled steel structure, and earthquake records were used to check the lateral and vertical stability and effectiveness of the isolators. According to the results all three types of isolators turned out to be effective in reducing the acceleration induced by the earthquake vibration.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.176-179
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• 2011

국내에서는 방화구획을 설정하여 화재 확산 방지 및 재실자의 대피 시간을 확보하고 있다. 방화구획에 설치되는 방화문은 방화문의 내화시험방법(KS F 2268-1)에 따라 시험을 거쳐 성적서를 발급 받은 제품에 대해 설치하도록 의무화 하고 있다. 그러나 본 시험방법은 시험체 제작, 설치 및 의뢰시험비용 등 상당한 비용이 소요될 뿐 아니라 제작, 설치, 시험에 소요되는 시간 또한 길다. 축소실험장치는 목재방화문 개발 중 재료의 내화성능을 평가할 장치로 개발되었으며, 표준시간-가열 온도곡선을 상회하는 가열실험을 통해 재료의 내화성능 결과를 얻을 수 있다. 본 실험에서는 난연 또는 불연성능이 뛰어난 재료를 대상으로 실험하였으며, 그 결과 난연목재는 5분, 마그네슘보드와 내화 직물원단은 60분의 내화성능을 갖춘 것으로 확인되었다. 이 결과를 토대로 방화문의 내화시험방법과 상관성을 도출하여 목재방화문 개발의 지표로 활용 가능하게 되었다.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.455-456
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• 2009

Although pseudo-dynamic test and shaking table test have been performed using small scale models to evaluate the seismic performance of RC structures, researches on similitude law are not sufficient. This study presents a reasonable similitude law for improvement of economical efficiency and reliability.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.11a
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• pp.45-46
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• 2013

본 연구는 침윤소화약제의 소화성능평가를 위해 자체제작 축소모형 실험장치를 이용하여 목재를 대상으로 실험을 진행하였다. 물과 7종의 침윤소화약제를 소화용수로 하여 성능평가 실험을 진행함으로써 물과 침윤소화약제의 명확한 변별력을 확인하고자 하였다. 실험결과 침윤소화 약제의 경우 7종 모두 유사한 소화 성능 패턴을 나타내는 것을 확인하였으며 동일 조건에서 물의 경우 재발화가 발생함으로써 명확한 변별력을 확인하였다.