• 대한기계학회논문집
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• 제18권9호
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• pp.2358-2367
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• 1994

This paper presents techniques for evaluation and compensation of total measuring errors in a commercial CMM. The probe errors as well as the machine geometric errors are assessed from probing of the mechanical artefacts such as shpere, step, and rings. For the error compensation, the integrated volumetric error equations are considered, including the probe error adn the machine geometric error. The error compensation is performed on the absolute scale coordinate system, in order to overcome the redundant degree of freedom in the CMM with multi-axis probe. A interface box and corresponding software driver are developed for data intercepting/correction between the machine controller and machine, thus the volumetric errors can be compensated in real time with minimum interference to the operating software and hardware of a commercial CMM. The developed system applied to a practical CMM installed on the shop floor, and demonstrated its performance.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.616-623
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• 2013

One of the oldest, most common engineering problems is measuring the dimensions of different objects and the distances between locations. In AEC/FM, related uses vary from large-scale applications such as measuring distances between cities to small-scale applications such as measuring the depth of a crack or the width of a welded joint. Within the last few years, advances in applying new technologies have prompted the development of new measuring devices such as ultrasound and laser-based measurers. Because of wide varieties in type, associated costs, and levels of accuracy, the selection of an optimal measuring technology is challenging for construction engineers and facility managers. To tackle this issue, we present an overview of various measuring technologies adopted by experts in the area of AEC/FM. As the next step, to evaluate the performance of these technologies, we select one indoor and one outdoor case and measure several dimensions using six categories of technologies: tapes, total stations, laser measurers, ultrasound devices, laser scanners, and image-based technologies. Then we evaluate the results according to various metrics such as accuracy, ease of use, operation time, associated costs, compare these results, and recommend optimal technologies for specific applications. The results also revealed that in most applications, computer vision-based technologies outperform traditional devices in terms of ease of use, associated costs, and accuracy.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.132.1-132
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• 2001

In this paper, we have studied for development of unmanned remote supervisory system using mobile communication network, not wire network, not to be affected by space or distance. The unmanned remote supervisory system consists of data processing unit main part and measuring systems (modules part)-temperature measuring module, humidity measuring module and human body sensing module. The data processing unit to collect and process informations of each measuring module has the functions of data communication between a mobile cellular telephone and measuring systems. Each measuring module has supervisory and warning functions for a target of supervision. And then we have designed each system and evaluated accuracy and reliability of the combined total system.

• 산업기술연구
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• 제31권B호
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• pp.9-15
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• 2011

Nowadays, the Surveying field is growing rapidly in terms of technology such as TS(Total Station) surveying, photographic surveying, digital aerial photogrammetry, utilization of GIS(Geographic Information System) using high-resolution satellite imagery, obtaining 3D Coordinate using GPS. But control point surveying, benchmark measuring, and field Surveying are still performed by the engineers in the field. So, 3D yerrestrial laser scanner comes to the fore recently. 3D terrestrial laser scanner can get 3D coordinate about a number of sites of the subject in a short period with high accuracy. This paper compared the accuracy of data from the performance using 3D terrestrial laser scanner with that of TS. It also obtained the geopositioning accuracy result equivalent to the surveying result of TS. With further researches in the future, it is expected to be used not only in LiDAR itself but also in various areas like reconnaissance Surveying and construction by combining with TS or other Surveying equipments.

• The Journal of Advanced Prosthodontics
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• 제13권4호
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• pp.191-204
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• 2021

PURPOSE. The purpose of this study is to present a methodology to evaluate the accuracy of intraoral scanners (IOS) used in vivo. MATERIALS AND METHODS. A specific feature-based gauge was designed, manufactured, and measured in a coordinate measuring machine (CMM), obtaining reference distances and angles. Then, 10 scans were taken by an IOS with the gauge in the patient's mouth and from the obtained stereolithography (STL) files, a total of 40 distances and 150 angles were measured and compared with the gauge's reference values. In order to provide a comparison, there were defined distance and angle groups in accordance with the increasing scanning area: from a short span area to a complete-arch scanning extension. Data was analyzed using software for statistical analysis. RESULTS. Deviations in measured distances showed that accuracy worsened as the scanning area increased: trueness varied from 0.018 ± 0.021 mm in a distance equivalent to the space spanning a four-unit bridge to 0.106 ± 0.08 mm in a space equivalent to a complete arch. Precision ranged from 0.015 ± 0.03 mm to 0.077 ± 0.073 mm in the same two areas. When analyzing angles, deviations did not show such a worsening pattern. In addition, deviations in angle measurement values were low and there were no calculated significant differences among angle groups. CONCLUSION. Currently, there is no standardized procedure to assess the accuracy of IOS in vivo, and the results show that the proposed methodology can contribute to this purpose. The deviations measured in the study show a worsening accuracy when increasing the length of the scanning area.

• 융복합기술연구소 논문집
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• 제6권2호
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• pp.29-33
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• 2016

Recently, the authors of this paper proposed newly the correlation model to calculate the horizontal global solar radiation in Korea based the Zhang-Huang (ZH) model proposed in 2002 for China. Previous study was pronounced the correlation with a new term of the duration of sunshine proved as being closely related with the hourly solar radiation in Korea into ZH model. And then another modified correlation for the regions without measuring cloud cover was proposed and evaluated the accuracy and validity for those regions. So, this study was performed to propose modified correlation to calculate the horizontal global solar irradiance of non-measuring cloud-cover regions. Finally, this study proposed the new correlation that could well predict hourly and daily total solar radiation for all regions, various seasons, and various weather conditions including overcast and clear, with higher accuracy and lower error than other models proposed ever before in Korea for non-measuring cloud-cover regions.

• 대한공간정보학회지
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• 제10권2호
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• pp.87-95
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• 2002

실시간 동적(Real Time Kinematic) GPS는 실시간으로 높은 정밀도의 위치결정을 가능케 해준다. 만약 미지정수를 구하기 위하여 정수해를 사용한다면 수 mm의 정확도를 얻을 수 있고, 실 수해를 얻는다면 수십 cm 의 정확도를 얻을수 있다. 본 연구에서는 통일 측점에 대해 기존의 재래식 측량기법(Total Station), 정적(Static) 상대측위 GPS기법과 현장 Calibration에 의한 실시간 동적(Real Time Kinematic) GPS기법에 의해 측량을 수행하여 각 기법별 측정의 정확도 등을 비교 분석하여 현장 Calibration에 의한 실시간 동적 (Real Time Kinematic) GPS기법의 정확도를 분석고자 한다. 국소지역에서 기존의 실시간 동적(Real Time Kinematic) GPS방식을 보완한 현장 Calibration에 의한 실시간 동적(Real Time Kinematic) GPS 측량을 수행한 결과, 미지정수해의 고정해를 얻지 못하는 경우를 제외하고는 모두 6cm 이하의 오차가 나타났고, Control Point의 측점수를 3개와 4개로 변화시켜 실시간 동적(Real Time Kinematic) GPS 측량을 수행한 결과 두 측정치의 차이는 최대 3cm로 나타났다. 최종적으로 국소지역에서도 현장 Calibration에 의한 실시간 동적(Real Time Kinematic) GPS기법이 사용가능함을 알 수 있었다.

• Journal of Applied Biological Chemistry
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• 제44권4호
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• pp.177-179
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• 2001

Traditional wet chemical methods for testing of soil properties require extensive time and labor, and cause the discharge of pollutants, making them undesirable for routine soil analyses. This research was conducted to improve the accuracy of soil properties in soil fertility assessments. A total of 140 finely ground soil samples were used to obtain accurate calibrations and validation for estimating soil moisture, OM, and T-N. Finely ground soil samples satisfied the improved accuracy for routine NIR measuring of the field soils. The results indicated that NIR spectroscopy could be used as a routine method for quantitatively determining OM, moisture, and T-N of field soil, although this technique requires many combinations of sample pretreatments and data manipulations to obtain optimal predictions.

• Journal of Magnetics
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• 제21권4호
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• pp.603-615
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• 2016

In this study, in order to determine the validity and accuracy of MR imaging of 3D gradient dual echo 2-point DIXON technique for measuring abdominal adipose tissue volume and distribution, the measurements obtained by CT were set as a reference for comparison and their correlations were evaluated. CT and MRI scans were performed on each subject (17 healthy male volunteers who were fully informed about this study) to measure abdominal adipose tissue volume. Two skilled investigators individually observed the images acquired by CT and MRI in an independent environment, and directly separated the total volume using region-based thresholding segmentation method, and based on this, the total adipose tissue volume, subcutaneous adipose tissue volume and visceral adipose tissue volume were respectively measured. The correlation of the adipose tissue volume measurements with respect to the observer was examined using the Spearman test and the inter-observer agreement was evaluated using the intra-class correlation test. The correlation of the adipose tissue volume measurements by CT and MRI imaging methods was examined by simple regression analysis. In addition, using the Bland-Altman plot, the degree of agreement between the two imaging methods was evaluated. All of the statistical analysis results showed highly statistically significant correlation (p<0.05) respectively from the results of each adipose tissue volume measurements. In conclusion, MR abdominal adipose volumetry using the technique of 3D gradient dual echo 2-point DIXON showed a very high level of concordance even when compared with the adipose tissue measuring method using CT as reference.

• 한국컴퓨터정보학회논문지
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• 제28권2호
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• pp.99-110
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• 2023

논문은 LiDAR 점군 데이터를 사용하여 흉고 직경과 수고를 예측하는 ForestLi 시스템을 제안한다. ForestLi 시스템이 LiDAR 점군 데이터를 처리하는 과정은 다음과 같이 여러 단계로 진행된다. 다운샘플링, 이상점 제거, 지표면 분할, 지표면 정규화, 수간 추출, 개체목 분할, 흉고 직경 측정, 수고 측정. LiDAR 점군 데이터를 처리하는 상용 시스템 LiDAR360은 하측 식생과 개체목 분할 오류를 사용자가 직접 수정해야 한다. ForestLi 시스템은 하측 식생에 해당하는 LiDAR 점군 데이터를 자동으로 제거한다. 결과적으로 ForestLi 시스템이 LiDAR360보다 전체 수행시간을 줄이고, 흉고 직경과 수고 예측의 정확성을 높였다. 실험을 통해서 제안된 ForestLi가 LiDAR360 시스템보다 흉고 직경과 수고 측정의 정확성과 전체 실행시간 측면에서 우수하다는 것을 보여주었다.