• 한국산업보건학회지
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• 제11권1호
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• pp.48-55
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• 2001

The purpose of this study was to evaluate the analytical accuracy and precision of microwave oven digestion/atomi absorption spectrophotometry (AAS) for analyzing airborne chromium collected on mixed cellulose ester membrane (M filter from the work environment, and to compare the accuracy and the precision with those of the National Institute for Occupational Safety and Health (NIOSH) Method #7024 hot plate digestion/AAS method. For this study, field air sample pairs were collected from a electroplating process, and spiked samples in a laboratory were prepared and using these samples. Two digestion methods were comp; and evaluated in terms of recovery rate and bias as indices of accuracy and coefficient of variation as a index of precision. The results and conclusions are as follows. In spiked samples, the accuracies (% mean recoveries) of hot plate/AAS and microwave oven/AAS method were 97.19%, 97.1%, respectively, and the precisions (pooled respectively, and the precisions (pooled coefficient of variance, $CV_{pooled}$) 6.93% and 3.88%, respectively. The biases of hot plate ani microwave oven methods were 4.56 - 14.7% and 2.22 - 7.42% respectively. There was no statistically significant difference between hot plate and microwave oven methods recovery rates of spiked samples (p>0,05). Also, no statistically significant difference was shown among the concentrations of air samples determined by two method (p>0.05). In conclusion, microwave oven/AAS method h excellent accuracy and precision, and advantages such as time-saving and simple procedure in comparison with the classical NIOSH method. Therefore, this method can be use widely to analyze airborne chromium collected on MCE filter from the work environments.

• 한국ITS학회 논문지
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• 제17권5호
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• pp.117-127
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• 2018

본 연구에서는 대학 캠퍼스를 대상으로 드론을 활용한 정사영상 및 지형모델의 생성 방안을 제시하고 정확도 평가를 실시하였다. 나아가 기존 대부분의 정확도 평가를 위한 연구에서 GPS 자료를 활용한 사례가 대부분 이였으나 본 연구에서는 삼각수준측량을 통해 얻은 기준값을 활용한 정확도 평가 및 검증을 실시하였다. 정확도 분석 결과 모든 시나리오에서 항공사진측량 작업규정에서 정한 허용범위 내의 성과를 얻어 드론을 활용한 항공사진측량 및 응용분야에 활용가능성을 확인하였으며, 정교한 DTM을 작성하기 위해서는 정밀 분류과정을 통해 빌딩, 수목, 인공 객체 등의 간섭을 없애고 정확한 표면의 높이의 등고선(Contour) 작성이 가능한 방안을 제시하였다. 본 연구의 성과는 드론을 활용한 지형모델 생성 및 정확도 평가에서 향후 관련 분야의 기초적 자료로 활용될 것으로 기대된다.

• 대한치과기공학회지
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• 제37권1호
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• pp.9-15
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• 2015

Purpose: The purpose of this study was to compare the accuracy of the maxillary three-unit fixed dental prosthesis (FDPs) made using two CAD/CAM milling machines : DCM Group(Dentaim CAD/CAM milling machine), WCM Group(Wieland CAD/CAM milling machine). Methods: Each of 10 duplicate models was scanned by blue light scanner(Identica, Medit, Korea), and the three-unit FDPs (STL file) was designed using DelcamCAD. A total of 20 three-unit FDPs was fabricated, comprising 2 groups of 10 specimens each (shrinkage ratio is 1:1). The first three-unit FDPs STL file was used as a CAD reference model (CRM). Obtained STL files by scanning the inner surface of three-unit FDPs were convened into the point clouds-ASC II files. Discrepancies between the point clouds and CRM were measured by superimposition software. Statistical methods to analyze the data were used non-parametric method. The mean (SD) values were compared by a Mann-Whitney U-test. Type one error rate was set at 0.05. Results: WCM group had small discrepancies with $2.17{\mu}m$ of mean value compared to $4.44{\mu}m$ in DCM group. The accuracy values between the two groups showed a sratistically significant difference (Table 2, p<.05). Conclusion: The accuracy of the three-unit fixed dental prosthesis(FDPs) made of two CAD/CAM milling machines were statistically different. Accuracy with which the prosthesis made of WCM group was superior.

• 한국운동역학회지
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• 제19권4호
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• pp.729-738
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• 2009

본 연구의 목적은 골프 퍼팅 시 숙련자와 초보자의 시각형태에 따른 운동학적 변인과 임펙트 시 퍼터 헤드의 정확성에 어떠한 차이가 있는지를 밝히는 것이다. 초보자 5명과 KPGA 세미프로 이상의 자격을 가진 5명의 선수들이 실험에 참여하였다. 3대의 카메라를 이용한 APAS(Ariel Performance Analysis System) 동작분석 시스템을 이용하여 퍼터헤드의 정확성과 운동학적 변인을 구하여 분석하였다. 본 연구의 결과로 퍼팅 시 볼의 정확성, 운동학적 분석의 결과를 토대로 볼 때, 숙련자 집단에서는 퍼팅 시 시선형태가 전혀 영향을 미치지 않았다. 이는 곧 숙련자 집단의 경우 장기간의 연습을 통해 관절 동작이 고정되어 있어 기계적인 스트로크를 한다는 것을 확인할 수 있었다. 하지만, 초보자 집단의 경우 시선형태에 따른 퍼팅 양쪽 모두 어느 정도의 장 단점을 가지고 있는 것으로 판단된다. 또한, 퍼터헤드의 변위가 속도보다 정확성에 더 큰 영향이 미치는 것으로 사료된다.

• 한국조사연구학회지:조사연구
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• 제11권1호
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• pp.1-18
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• 2010

본 논문에서는 패널조사에서 발생하는 웨이브 무응답을 대체하는 방법을 고찰하였다. 패널조사에서는 이전 조사 데이터를 무응답 대체에 활용할 수 있기 때문에 이러한 성질을 이용하면 횡단면 무응답 대체보다 더 효과적인 웨이브 무응답 대체법을 찾을 수 있다. 먼저 웨이브 무응답 대체를 사용하는 해외의 주요 패널조사를 살펴보고, 웨이브 무응답 대체방법 중 종단면 회귀대체법, 이월대체법, 최근방 회귀대체법, 그리고 행렬대체법을 고찰하였다. 그리고 웨이브 무응답 대체법의 성능을 비교하기 위하여 한국복지패널 데이터를 대상으로 모의실험을 실시하였다. 성능을 비교하기 위하여 평균대체, 회귀대체, 비대체, 최근방 대체, 핫덱 대체를 고려하였고 성능평가 지표로는 예측 정확성 지표와 추정 정확성 지표를 이용하였다. 모의실험 결과 비대체, 행렬대체는 두 지표 모두 우수했고, 회귀대체, 종단면 회귀대체, 이월대체는 예측 정확성은 우수한 반면 추정 정확성은 다소 떨어졌으며, 반대로 최근방 회귀대체, 최근방 대체, 핫덱 대체는 예측 정확성은 떨어지나 추정 정확성은 높은 것으로 나타났다. 마지막으로 평균 대체는 두 지표 모두 좋지 않았다.

• Clinical and Experimental Reproductive Medicine
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• 제32권3호
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• pp.223-230
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• 2005

Objective: This study was performed to evaluate the accuracy of hysterosalpingography (HSG) for evaluating female infertility patients by comparison with hysteroscopic and laparoscopic examination. Methods and Material: Total 219 infertile patients were retrospectively analyzed between January 1, 2002 and December 31, 2003. Ninety seven patients (44.3%) were primary infertility, 122 patients (55.7%) were secondary infertility. We performed hysteroscopic and laparoscopic examination on next cycle when HSG revealed any abnormal finding, and 3~6 cycles later if HSG was normal. Results: The accuracy of HSG was 65.2% compared with hysteroscopic examination (sensitivity 88.4%, specificity 46.4%, false positive rate 53.6%, false negative rate 11.6%). The most common abnormal finding of hysteroscopy was uterine synechia (67.4%) followed by endometrial polyp, uterine anomaly (e.g. uterine septum), endometrial hyperplasia. Compared with laparoscopic examination, the accuracy of HSG was 76.9% (sensitivity 98.9%, specificity 70.6%, +LR 3.36, -LR 0.02). The positive predictive value of normal patent tube was excellent (99.6%) but that of proximal tubal blockage was only 46.7%. The unilateral tubal obstruction of HSG was poor accuracy (+LR 3.85 -LR 0.68) and 70% of those was patent by laparoscopic examination. Laparoscopic examination also revealed that 53% of patients had peritubal adhesion and 37% of patients has additional pelvic findings, especially endometriosis. Among the patients had normal HSG, 53.5% patients with normal ultrasonography was diagnosed endometriosis (25.6% of them had endometriosis stage I-II). Conclusion: Normal HSG shows a high negative predictive value. Nevertheless, the incidence of associated pelvic disease in the normal HSG group is high enough to warrant diagnostic laparoscopy if nonsurgical treatment is unsuccessful. Because HSG has poor accuracy in predicting distal tubal blockage and peritubal adhesion, and poor positive predictive value of proximal tubal blockage, laparoscopic examination could be considered in abnormal HSG group.

• The Journal of Advanced Prosthodontics
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• 제13권5호
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• pp.327-332
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• 2021

PURPOSE. The purpose of this in vitro study was to evaluate the accuracy of digitally designed removable partial denture (RPD) frameworks, constructed by additive and subtractive methods castable resin patterns, using comparative 3D analysis. MATERIALS AND METHODS. A Kennedy class III mod. 1 educational maxillary model was used in this study. The cast was scanned after modification, and a removable partial denture framework was digitally designed. Twelve frameworks were constructed. Two groups were defined: Group A: six frameworks were milled with castable resin, then casted by the lost wax technique into Co-Cr frameworks; Group B: six frameworks were printed with castable resin, then casted by the lost wax technique into Co-Cr frameworks. Comparative 3D analysis was used to measure the accuracy of the fabricated frameworks using Geomagic Control X software. Student's t-test was used for comparing data. P value ≤ .05 was considered statistically significant. RESULTS. Regarding the accuracy of the occlusal rests, group A (milled) (0.1417 ± 0.0224) showed significantly higher accuracy than group B (printed) (0.02347 ± 0.0221). The same results were found regarding the 3D comparison of the overall accuracy, in which group A (0.1501 ± 0.0205) was significantly more accurate than group B (0.179 ± 0.0137). CONCLUSION. In indirect fabrication techniques, subtractive manufacturing yields more accurate RPDs than additive manufacturing.

• 한국융합학회논문지
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• 제12권3호
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• pp.35-41
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• 2021

본 연구는 진동을 융합한 소도구운동이 초등학교 야구선수들의 타격속도와 타격정확도에 미치는 영향을 알아보는데 목적이 있다. 주 3회 6주간 실시하였다. 실험군과 대조군 각각 20명씩으로 나누었다. 실험군은 진동을 융합한 소도구운동을 시행하였으며, 대조군은 일반적 운동을 시행하였다. 타격속도와 타격정확도를 측정하였다. 진동운동 실험군과 대조군 모두 중재 전과 후 타격속도와 타격정확도에서 군내 유의한 차이가 나타났다. 실험군과 대조군의 중재 후 군간 비교에서 타격정확도에서 유의한 차이가 나타났다. 진동을 융합한 소도구운동이 초등학교 야구선수들의 타격속도와 타격정확도를 증진시키는데 효과적인 방법이라고 사료된다. 향후 연구에서는 연령별과 스포츠 관련 질환을 가진 대상자에 대한 후속연구가 필요하다.

• Journal of Animal Science and Technology
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• 제63권6호
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• pp.1232-1246
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• 2021

Recently, the cattle genome sequence has been completed, followed by developing a commercial single nucleotide polymorphism (SNP) chip panel in the animal genome industry. In order to increase statistical power for detecting quantitative trait locus (QTL), a number of animals should be genotyped. However, a high-density chip for many animals would be increasing the genotyping cost. Therefore, statistical inference of genotype imputation (low-density chip to high-density) will be useful in the animal industry. The purpose of this study is to investigate the effect of the reference population size and marker density on the imputation accuracy and to suggest the appropriate number of reference population sets for the imputation in Hanwoo cattle. A total of 3,821 Hanwoo cattle were divided into reference and validation populations. The reference sets consisted of 50k (38,916) marker data and different population sizes (500, 1,000, 1,500, 2,000, and 3,600). The validation sets consisted of four validation sets (Total 889) and the different marker density (5k [5,000], 10k [10,000], and 15k [15,000]). The accuracy of imputation was calculated by direct comparison of the true genotype and the imputed genotype. In conclusion, when the lowest marker density (5k) was used in the validation set, according to the reference population size, the imputation accuracy was 0.793 to 0.929. On the other hand, when the highest marker density (15k), according to the reference population size, the imputation accuracy was 0.904 to 0.967. Moreover, the reference population size should be more than 1,000 to obtain at least 88% imputation accuracy in Hanwoo cattle.

• 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.