• The korean journal of orthodontics
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• v.32 no.1 s.90
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• pp.59-69
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• 2002

The purpose of this study was to evaluate the reproducibility of lateral cephalometric landmarks according to radiographic image enhancement, and to contribute to the identification of cephalometric landmarks. Lateral cephalograms of ten individuals were taken and stored into computer. The images were then enhanced up to four grades by Quick Ceph Image Pro$^{TM}$ on condition that the gray-scale equalization number was 50 and the detail enhancement number was 50. After thirty two landmarks were identified on monitor images by five observers, the deviations from the mean, the distances estimated between identified points and the mean point of five identified points, were evaluated for each landmark at each enhancement grade. Through the statistical analysis, following results were obtained. 1. In case of unenhanced radiographic images, the inter-observer reproducibility of the landmarks showed a large variation. 2. The comparison of deviation from the mean according to the degree of radiographic image enhancement for each landmark showed that the inter-observer reproducibility was significantly different at 5 landmarks. 3. The landmark of pterygomaxillary fissure showed higher reproducibility at enhancement grade 1 and 2 images than at unenhanced images. So did the landmark of posterior nasal spine at enhancement grade 1 images, and the landmark of menton at enhancement grade 2, 3 and 4 images respectively. The above results suggest that the reproducibility of some landmarks can be increased by radiographic image enhancement during the identification of the lateral cephalometric landmarks on the monitor.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.249-258
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• 2000

본 논문에서는 지반-구조물 상호작용계의 강성에 관련된 물성값들을 지진계측결과를 바탕으로 효과적으로 추정할 수 있는 방법에 대해 연구하였으며 제안된 방법의 검증은 국제공동 연구의 일환으로 최근 대만의 화련에 건설된 대형지진시험구조물에서 계측된 지진 응답을 사용하여 수행하였다. 지반-구조물 상호작용계의 지진응답해석을 위해서 구조물과 근역지반은 축대칭유한요소로 모형화하고 원역지반은 축대칭 무한요소를 사용하였으며 이때 입력 지진하중은 부구조법에 근거한 파입력기법이 고려되었다 지진계측결과를 사용하여 각 영역의 물성값을 제약적 최속강하법을 사용하여 추정하였는데 추정된 계수들을 사용하여 계산된 지진응답이 계측치와 매우 잘 일치하여 추정결과의 타당성을 검증할 수 있었다.

• Journal of the Korean GEO-environmental Society
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• v.12 no.6
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• pp.53-60
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• 2011

The purpose of this study is to propose a method that can reliably evaluate the fundamental period of a rockfill dam using the micro-earthquake records, which were obtained at the domestic dam sites. For total 20 micro-earthquake records obtained at 7 domestic rockfill dam sites against 6 earthquake events which recently occurred, the fundamental periods of seven rockfill dams were evaluated by two kinds of methods; one is a method using acceleration amplification ratio and the other is a method using acceleration response spectrum ratio. Applicability of each method to evaluation of fundamental periods of domestic rockfill dams was examined. In the moderate seismicity region like our country, the method using acceleration response spectrum ratio, which could evaluate the fundamental period of the rockfill dam using the ratio between the response spectrum for acceleration observed at the dam crest and that observed at the dam base or abutment, proved to be reliable and was proposed in this study. From the results of analyses, it was found that the proposed method could consistently evaluate the fundamental period of the rockfill dam and the results obtained by the proposed method were very similar to the results by the existing method which was proposed from the analysis for the earthquake records observed at Japanese dam sites.

• Journal of the KSME
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• v.31 no.6
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• pp.527-532
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• 1991

반응성 유동의 연구에 있어서는 단유동 등 온유동 보다는 많은 계측정보가 필요함은 누구나 알고 있으며, 경제적인 궁여지책으로 종래에 많이 쓰여 오던 계측방법을 복합하여 각 계측방법이 갖고 있는 한계성을 극복함과 동시에 반응성 유동의 여러 가지 정보를 얻을 수 있다는 지극히 당연한 결과제시와 몇 가지 방안을 제안하게 되었으니 말이다. 단, 분자 레벨의 계측기술의 개발과 아 울러 복합계측의 시스템화도 이에 못지 않게 중요함을 지적하고 싶고 이런 류의 아이디어가 서로 교환될 수 있는 계기가 되기를 고대한다.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2708-2710
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• 2005

본 연구는 매년마다 반복되는 하천의 수해예방 및 차후 대책수립을 위해 재해관리자가 원거리에서 다수의 하천 수위를 실시간 파악하도록 압력센서를 이용한 수위 계측기와 계측결과를 CDMA망을 통해 전송하는 데이터로거 시스템 개발에 관한 것이다. 본 연구에서 개발한 압력센서를 이용한 무선원격 수위계측기는 전원환경이 열악한 오지에 장착하여 수년간의 동작을 보장할 수 있는 계측시스템으로서, 태양광을 이용한 자가발전에 의한 전원 충전과, 차세대 무선 통신시스템을 장착하여 독립적으로 실시간 자료를 수집할 수 있는 특징들을 가진다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.352-354
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• 2022

2020년 기준 금정터널 유지관리 계측센서의 정상 작동 실효성 검증 조사결과 정상작동 유효율은 14-2공구 6개 단면의 계측센서 41개중 7.3%, 14-3공구 10개 단면의 계측센서 83개중 24.1%로 편차가 큰 것으로 나타났으며, 전체 16개 단면의 계측센서 124개중 18.5%로 나타났다.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.331-337
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• 2015

By comparing and evaluating the neutron dose when running cyclotron in fixed type measuring machine and portable type measuring machine, we performed this study to see if there is any difference between the doses in both measuring devices. We performed correction 3 times for the portable type during the experiment. We measured the values 12 times for each correction, so total 36 times by using the fixed type and portable type once every 2 weeks from June 2012 to February 2014. The statistics for the portable type and fixed type for each experiment showed 0.186, 0.511, and 0.057, which are not statistically significant. Therefore, we have come to the conclusion that unless there is deviation based on the correction period of the portable type, correction of fixed type wouldn't be necessary. Also, reduction of social costs may be achieved if we install an alarm meter, which is relatively low priced compared to the high cost neutron measuring machine, when detecting higher level than the interested standard level.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.1
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• pp.53-60
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• 2016

This study analyzed a monitoring data, based on the initial limit values of monitoring in subway, of earth pressure and pore water pressure. The data is obtained from 8 sections of the Seoul metropolitan subway line No 6, 7 and 9 in about 5 years. Also, a research is performed to set up the limit values of management monitoring, which will be applied to management monitoring in tunnel, through comparing the limit values of overseas management monitoring data and that of domestic management monitoring data. And the result obtained from comparison show that the safety phase is 60% of allowable pressure, the attention phase is 80% of allowable pressure and the precision analysis phase is 100% of allowable pressure. Also, we presented a method of management monitoring by the absolute value which can be easily applied easily in practical affairs.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.1
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• pp.25-32
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• 2015

This study analyzed a monitoring data, based on the initial limit values of monitoring in subway, of concrete lining stress and reinforcement stress. The data is obtained from 7 sections of the Seoul metropolitan subway line No 6, 7, and 9 in about 5 years. Also, a research is performed to set up the limit values of management monitoring, which will be applied to management monitoring in tunnel, through comparing the limit values of overseas management monitoring data and that of domestic management monitoring data. And the result obtained from comparison shows that the safety phase is 60% of allowable stress, the attention phase is 80% of allowable stress and the precision analysis phase is 100% of allowable stress. Also, we presented a method of management monitoring by the absolute value which can be easily applied in practical affairs.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.603-605
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• 1999

본 논문은 통계적 Regression방법인 Alternating Conditional Expectation(ACE) 방법을 적용하여 다중계측기를 이용한 공간 변수의 분포에 대한 추정 혹은 재구성 문제를 분석하는 방법을 제시하고 있다. 한다. 계측기 설치 비용 및 설치 위치의 한계로 인해 완벽하게 이루어지기 힘든 공간 변수의 연속적인 분포 추정은 공정 시스템이나 안전성 관련 변수의 감시분야에 많이 응용되고 있다. 본 논문은 계측기 추가에 따르는 비용을 줄이거나 동일한 수의 계측기로 측정오차를 감소시킬 목적으로 가상계측기의 개념을 도입하고 이를 적용하기 위한 통계적 추정 방법론을 기술하고 있다. 수치모사를 통한 분석결과 본 방법은 비선형성이 큰 변수분포에 대해서도 Robust한 결과를 주는 것을 확인하였다.