• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.161-170
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• 2020

In this study, develop the seismic acceleration measurement data conversion and signal processing algorithms for improve the operational efficiency of the seismic acceleration measurement system installed for public facilities. Through the analysis of the seismic acceleration time history data, the evaluation methods and criteria and evaluating the safety of buildings were proposed. The system was applied to the test bed building to verify its operation and usability. It is expected to be used as a decision making support data and determining the direction and priority of disaster response in the event of an earthquake.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.75-83
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• 1998

This study was done to recognize the importance of errors in measurements of cephalometric radiograph and to find the anatomical structures those need special care to select as a reference points through the detection of the systematic errors and estimation of random errors. For this purose, 100 cephalometric radiographs were prepared by usual manner and 61 reference points, and 130 measurement variables were established. Measurement errors were detected and estimated by the comparison of the 25 randomly-selected samples for repeated measurements with the main sample. The following results were obtained : 1. In comparison of the repeated measurements, there were statistical significant differences in 24 variables which were 18.4% of 130 total variables. 2. The frequency of the difference in identification of the reference points between the repeated measurements was very high in the root apex of upper incisor(as), the most posterior wall of maxilla(tu), soft tissue nasion(n'), soft tissue frontal eminence(ft), and ad3 in airway. 3. After correction of reference points marking until the level of below 5% significance, the range of random errors were from 0.67 to 1.71 degree or mm. 4. The variable shown the largest random error was the interincisal angle(ILs-ILi). 5. Measurement errors were mainly caused by the lack of precision in anatomic definitions and obscure radiographic image. From the above results, the author could find the high possibility of errors in cephalometric measurements and from this point, we should include error analysis in all the studies concerning measurments. In is essential to have a concept of error analysis not only for the investigator but also for a reader of other articles.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.129-140
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• 1997

Conventional cephalometrics have inherent errors because their evaluation is performed in two-dimension for threedimensional object. To compensate these errors, three-dimensional cephalograms - derivation of three-dimensional data from conventional lateral and postero-anterior cephalograms - were developed. In this study, the accuracy and precision of three dimensional cephalograms were determined by means of 10 linear and 12 angular measurements on 36 acrylic skull models and by the comparison of conventional lateral cephalograms. The results were as follows 1. Mean difference between three-dimensional cephalograms and actual models in linear measurements was $0.94{\pm}0.62mm$ and mean rate of magnification of three-dimensional cephalograms was $100.31{\pm}0.91%$. There were no statistically significant differences between three-dimensional cephalograms and actual models in linear measurements(${\alpha}=0.1$). 2. Mean difference between conventional lateral cephalograms and actual models in linear measurements was $6.44{\pm}1.48mm$ and mean rate of magnification of lateral cephalograms was $106.99{\pm}1.45%$. There were statistically significant differences between lateral cephalograms and actual models in linear measurements(P<0.005). 3. Mean difference between three-dimensional cephalograms and actual models in angular measurements was $1.22{\pm}0.82^{\circ}$ and mean rate of magnification of three-dimensional cephalograms was $105.71{\pm}12.07%$. There were no statistically significant differences between three-dimensional cephalograms and actual models in angular measurements(${\alpha}=0.1$). 4. Mean difference between conventional lateral cephalograms and actual models in angular measurements was $1.70{\pm}0.94^{\circ}$ and mean rate of magnification of lateral cephalograms was $106.35{\pm}15.70%$. There were no statistically significant differences between lateral cephalograms and actual models in angular measurements(${\alpha}=0.1$). There were similarity between three-dimensional and lateral cephalograms in angular measurements.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.1
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• pp.29-35
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• 2019

In this paper, a low-cost dynamic measurement system using the RGB-depth camera, Microsoft $Kinect^{(R)}$ v2, is proposed for measuring time-varying free surface motion of liquid dampers used in building vibration mitigation. Various experimental studies are conducted consecutively: performance evaluation and validation of the $Kinect^{(R)}$ v2, real-time monitoring using the $Kinect^{(R)}$ v2 SDK(software development kits), point cloud acquisition of liquid free surface in the 3D space, comparison with the existing video sensing technology. Utilizing the proposed $Kinect^{(R)}$ v2-based measurement system in this study, dynamic behavior of liquid in a laboratory-scaled small tank under a wide frequency range of input excitation is experimentally analyzed.

• Journal of the Korean Geotechnical Society
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• v.39 no.9
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• pp.25-33
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• 2023

To effectively improve soft soils, it is necessary to perform ground behavior characteristics and stability management through measurement activities when embankment of structures on soft soils is conducted. However, there are many differences between the actual ground behavior and the initial design plan. To address this issue, this study analyzed the measured settlement in the Yeongam-Haenam areas using the Hyperbolic method to predict the settlement based on the measurement data. From the completion time of the embankment in the target area, the final settlement was predicted through the change in the degree of consolidation by the measurement period. Furthermore, the final settlement according to the change in degree of consolidation was compared and analyzed through finite element analysis and field measurement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1282-1287
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• 2005

The accuracy of chip alignment in inferior product inspection of COG(Chip On Glass) to be measured a few micro unit is very important role since the accuracy of chip inspection depends on chip alignment. In this paper, we propose the area segmentation pattern matching method to enhance the accuracy of chip alignment. The area segmentation pattern matching method compares, and matches correlation coefficients between the characteristic features within the detailed area and the areas. The three areas of pattern circumference are learned to minimize the matching error by bad pattern. The proposed method has advantage such as reduction of matching time, and enhanced accuracy since the characteristic features are searched within the segmented area.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2042-2045
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• 2008

수자원을 효율적으로 이용하고 관리하기 위해서는 정확한 유출량을 파악하는 것이 매우 중요하다. 그러나 소하천에서의 수문자료의 측정은 거의 이루어지지 않고 있는 실정이며, 따라서 대부분의 소하천 유역을 미계측 유역으로 분류할 수 있다. 본 연구에서는 수문관측 자료가 없는 소하천에서의 Soil and Water Assessment Tool(SWAT)의 적용가능성을 판단하였다. 남원에 위치하고 있는 지방 2급 하천인 광치천을 대상지점으로 SWAT 모형을 이용하여 일유출량을 모의하였다. 모의 값의 정확성을 판단하기 위하여 2004년의 저 평수기 측정 자료와 SWAT 모형으로부터의 모의 값을 비교 분석하였다. 또한 SWAT 모형에 의한 결과와 면적비유량법에 의한 결과를 비교하였다. 모의 결과 SWAT 모형에 의한 결과는 RMSE가 0.189이고, 면적비유량법에 의한 결과는 0.207로 나타났으며, 따라서 SWAT 모형에 의한 유출량 모의가 소하천에서도 적용 가능함을 판단할 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.267-268
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• 2011

본 논문에서는 스마트폰을 이용한 실시간 건강정보 모니터링 및 데이터 관리 시스템을 설계 및 구현하였다. 이 시스템은 심전도 계측 모듈에서 획득한 심전도 데이터를 스마트폰 상에서 누구나 손쉽게 자신의 심전도를 모니터링 할 수 있고 데이터베이스 서버로 계측된 데이터를 전송함으로써 데이터의 관리 및 공유가 가능한 시스템이다. 현재 가장 주목받고 있는 휴대용 개인 정보화 기기인 스마트폰을 기반으로 한 모니터링 시스템과 데이터베이스 서버를 활용한 심전도 데이터 관리 시스템을 최대 장점으로 들 수 있으며, 기존의 시스템에 비해 휴대성, 확장성, 편의성, 정확성, 비용 등에서 뛰어나 보다 나은 시스템 구현의 가능성을 확인할 수 있었다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.66-68
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• 2015

최적항로 지원 시스템은 실해역 속도 성능 예측방법에서의 선택 근거확보와 정확도 평가를 위한 효과 검증이 반드시 필요하다. 하지만 이 같은 성능검증에 있어서 동일한 선박에 대한 다양한 대안 항로에서의 동시성능계측이 불가능하기 때문에 효과를 직접 비교하기는 상당히 어렵다. 따라서 본 논문에서는 최적항로 지원 시스템의 효과 검증을 위한 간접적인 절차를 제안하였고, 시스템의 내부 분석코드를 이용하여 효과를 비교 검증하였다. 그 절차는 1) 계산의 근거 인기상 정보의 정확성 검증, 2) 실제 항로에서의 성능예측계산의 신뢰성 확인, 3) 신뢰성이 확보된 계산방법을 이용한 최적항로선택, 4) 실제 항로와 최적항로의 연료 효율성 비교의 4단계로 이루어진다. 대상 선박은 폴라리스쉬핑의 솔라돌핀호(208k BC)이며 실선 운항 데이터는 최적항로 지원 시스템을 통하여 직접 계측하였다. 그 결과 호주-한국 항차에서 최적항로를 항해할 경우 약 6.0%의 연료 절감 효과를 기대할 수 있음을 확인하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.396-399
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• 2010

본 논문에서는 실제 건설중인 초고층건물을 대상으로 상시 풍하중을 이용한 풍진동 모니터링을 통해 고유주기와 감쇠비를 예측하고 이를 설계단계에서의 구조해석 및 가정에 의한 고유주기 및 감쇠비와 비교하였다. 이를 위해 시공중 풍진동계측을 실시하여 고유주기와 감쇠비를 측정하고, 시공단계를 고려한 구조해석모델을 통해 고유주기와 감쇠비가 유사하도록 모델을 수정한 후 이를 바탕으로 완공단계에서의 구조해석모델을 재구성하였다. 이 완공단계에서의 구조해석모델을 바탕으로 완공후의 고유주기 및 감쇠비를 예측하고 이를 설계단계에서의 값과 비교하였다. 향후 이러한 실계측 및 분석을 충분히 축적된다면 초고층설계시의 보수적인 가정사항들을 개선시키고, 풍동실험에 의한 풍진동 산정시의 정확성을 크게 향상시킬 것으로 기대된다.