• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.396-397
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• 2009

• 한국전산구조공학회논문집
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• 제28권3호
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• pp.275-281
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• 2015

본 연구에서는 동조액체기둥감쇠기의 비선형감쇠항을 등가점성감쇠항으로 치환한 등가선형 동조액체기둥감쇠기 모델을 유도하였으며 동조액체기둥감쇠기의 동적거동인 고유진동수와 감쇠비를 이론적으로 파악하였다. 동조액체기둥감쇠기에 일정한 전기장을 형성한 후 동조액체기둥감쇠기의 수직운동에 의해 발생되는 가변전압을 측정하여 수조 내부의 수위로 변환하는 식을 유도하였다. 또한 본 연구에서 제안한 동조액체기둥감쇠기의 수위측정 시스템의 타당성을 검증하기 위하여 고가의 전기 용량식 파고계와 비교 및 검증하였다. 마지막으로 본 연구에서 제안한 수위측정 시스템을 동조액체기둥감쇠기에 적용, 진동대 실험을 실시하여 고유진동수와 감쇠비를 파악하였고, 이론상의 고유진동수와 실험상의 고유진동수가 일치하였음을 확인하였으며, 진동수비 변화에 따른 동조액체기둥감쇠기의 감쇠비 변화를 확인하였다.

• 한국정보통신학회논문지
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• 제15권2호
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• pp.413-418
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• 2011

증기표의 상태량들은 실험을 통하여 얻어진 값이거나 적절한 가정하에서 근사적으로 계산된 값이다. 따라서 증기표의 상태량들은 기본적으로 오차를 가지고 있다. 또한 이러한 상태량을 수치해석에서 사용하기 위하여는 함수 근사를 통하여 모델링하여야 한다. 본 연구에서는 포화증기표에 대해 난수를 적절한 크기로 조절한 다음 원래의 성질들에 더하여 인위적으로 노이즈가 포함된 데이터를 만들어 측정오차를 포함하는 상태량의 대용으로 사용했다. 이 데이터의 모델링에는 신경회로망과 2차 스플라인 보간법을 사용되었다. 해석 결과 양단에서는 스플라인 보간법이 신경회로망보다 훨씬 더 적은 상대오차를 보였으며, 양단을 제외하면 신경회로망은 대체로 ${\pm}0.2%$, 스플라인 보간법은 ${\pm}0.5$~1.5%의 오차를 보였다. 이것은 사용 범위에서는 신경회로망이 스플라인 보간법보다 훨씬 더 적은 상대오차를 가진다는 것을 의미한다. 이 결과로부터 신경회로망이 스플라인 보간법보다 원래의 값은 더 잘 추적할 수 있으며, 신경회로망이 포화증기표의 모델링에 더 적절한 방법이라는 사실을 확인하였다.

• International Journal of Aeronautical and Space Sciences
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• 제11권3호
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• pp.234-239
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• 2010

The utilization of micro-electro-mechanical system (MEMS) gyros and accelerometers in low-level inertial measurement unit (IMU) influences cost effectiveness in a positive way under the condition that device error characteristics are fully calibrated. The conventional calibration process utilizes a rate table; however, this paper proposes a new method for achieving reference calibration data from the natural motion of pendulum to which the IMU undergoing calibration is attached. This concept was validated with experimental data. The pendulum angle measurements correlate extremely well with the solutions acquired from the pendulum equation of motion. The calibration data were computed using the regression method. The whole process was validated by comparing the measurement from the 6 sensor components with the measurements reconstructed using the identified calibration data.

• 설비공학논문집
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• 제2권2호
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• pp.137-141
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• 1990

When the relative humidity is measured with an aspirated psychrometer, three factors, which affect the measurement of relative humidity, are atmospheric pressure, the size of wet element and the wind velocity. This paper investigated the effects of the above three factors, and the computer code was developed in order to enhance the accuracy of the relative humidity measurement. As results, it is found that the relative humidity decreases by 6%RH with increasing atmospheric pressure from 650 mbar to 1100 mbar. It is found that the relative humidity drops down when the size of the wet element increases, though the effect of the size of the wet element is not significant. Finally, relative humidity increases with the increasing wind velocity. The difference between the psychrometic table in the present KS and the present results is about 2%RH maximum. As a conclusion, the three factors mentioned above should be considered in order to secure accurate measurement of relative humidity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.291-292
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• 2006

Currently A demand of high precision workpiece is increasing in industry. At present, roundness measuring machine using Air bearing, coordinate measuring machine that are used from measurement station. but these machines will not be able to apply to In-line process. because of like these machine's price are very expensive and measurement time is long. also, the complexity of conventional roundness measurement method based on fourier transform, it makes difficult to development analysis program. This work present new architecture of a Out-diameter measuring system fur analysis of roundness of product. In this system, the influence of table motion errors is minimize by using two LVDT sensor and knife edge contact tip. We are produce a test machine and make an experimenter on Out-diameter of test bearing. The measurement result compared with roundness measuring machine.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.702-705
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• 2005

Burr is an undesirable projection as result of plastic deformation. Burr minimization and effective deburring process are required strongly to reduce the cost of the parts. In doing these efforts, the precise burr measurement must be provided for the efficient process. For this purpose the conoscopic holography sensors are selected before. However, it has been very difficult to measure micro burrs less than $10{\mu}m$ due to their tiny and sharp geometries as well as the effect of ambient vibration during scanning. A new micro burr measurement system using high precision. Conoprobe sensor and XY table can measure the micro burrs which is less than $10{\mu}m$. Experiments were carried out showing that micro burr around $10{\mu}m$ was successfully measured and analyzed.

• Smart Structures and Systems
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• 제17권6호
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• pp.935-956
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• 2016

With the help of advanced image acquisition and processing technology, the vision-based measurement methods have been broadly applied to implement the structural monitoring and condition identification of civil engineering structures. Many noncontact approaches enabled by different digital image processing algorithms are developed to overcome the problems in conventional structural dynamic displacement measurement. This paper presents three kinds of image processing algorithms for structural dynamic displacement measurement, i.e., the grayscale pattern matching (GPM) algorithm, the color pattern matching (CPM) algorithm, and the mean shift tracking (MST) algorithm. A vision-based system programmed with the three image processing algorithms is developed for multi-point structural dynamic displacement measurement. The dynamic displacement time histories of multiple vision points are simultaneously measured by the vision-based system and the magnetostrictive displacement sensor (MDS) during the laboratory shaking table tests of a three-story steel frame model. The comparative analysis results indicate that the developed vision-based system exhibits excellent performance in structural dynamic displacement measurement by use of the three different image processing algorithms. The field application experiments are also carried out on an arch bridge for the measurement of displacement influence lines during the loading tests to validate the effectiveness of the vision-based system.

• 제어로봇시스템학회논문지
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• 제22권3호
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• pp.186-191
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• 2016

This paper addresses the development of 3D data acquisition system (3D scanner) based laser structured-light image. The 3D scanner consists of a stripe laser generator, a conventional camera, and a rotation table. The stripe laser onto an object has distortion according to 3D shape of an object. By analyzing the distortion of the laser stripe in a camera image, the scanner obtains a group of 3D point data of the object. A simple semiconductor stripe laser diode is adopted instead of an expensive LCD projector for complex structured-light pattern. The camera has an optical filter to remove illumination noise and improve the performance of the distance measurement. Experimental results show the 3D data acquisition performance of the scanner with less than 0.2mm measurement error in 2 minutes. It is possible to reconstruct a 3D shape of an object and to reproduce the object by a commercially available 3D printer.

• 농촌계획
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• 제20권4호
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• pp.165-182
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• 2014

The purpose of this study was to develop survey tools for diagnosis of capacity levels in business promotion of rural residents when performing a rural development project of a regional unit. The cases of previous studies were analyzed to select community capacity indicators related to a rural development project. Five indicators were derived : social capital, consciousness of participation, community spirit, and leadership. Based on the five indicators, measurement items of various capacities were selected and 54 survey items were selected through evaluation of experts twice. The pilot tests were conducted and targeted at Jeonnam song ho-jung village and Gyeongnam Haegeumgang village to identify derived survey items. In addition, descriptive statistic analysis and reliability analysis were conducted. As a result, survey items were corrected by reducing 10 items of the total 54 items. This results showed that using this tool could help us understand capacity levels of rural residents.