• Journal of Periodontal and Implant Science
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• 제40권4호
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• pp.172-179
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• 2010

Purpose: Accurate and exact measurement is an important factor for generating meaningful results in any properly designed study. If all the participating examiners are able to yield similar results, it will be possible to evaluate the objective results of the study more easily and quickly. The purpose of this study was to evaluate the intra- and inter-examiner reproducibility of histometric measurements in the intrabony periodontal defect model. Methods: One wall intrabony defects were surgically created at the distal aspect of the second and the medial aspect of the fourth mandibular premolars in the right and left jaw quadrants in twenty beagle dogs and the defect sites received the following ${\beta}$-tri calcium phosphate, growth differentiation factor-0, growth differentiation factor-100 and sham surgery. Histometric analysis was performed after 8 weeks. Histometric parameters were recorded and repeated at three months interval by three examiners. Intra- and inter-examiner reproducibility was assessed. Results: Most parameters of all the groups showed high intra- and inter-examiner reproducibility. Parameters including defect height, bone regeneration height, cementum regeneration height, and formation of junctional epithelium yielded interexaminer correlation ${\geq}0.9$. The intra-examiner reproducibility showed a high result, over 0.9. Conclusions: Histometric evaluation of the one-wall intra-alveolar periodontal defect model showed high reproducibility not only for a single given examiner but also among the three examiners.

• 대한치과교정학회지
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• 제30권5호
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• pp.543-552
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• 2000

본 연구는 natural head posture(NHP)를 이용하여 정모 두부 방사선 규격사진 촬영시 재현도를 알아보기 위하여 시행되었다. 두개 안면부의 기형이 없는 25세 전후의 성인 남녀 30명을 대상으로 통상적인 방법(술자 유도법)과 NHP에서 Head Posture Aligner를 이용한 방법(HPA법)으로 정모 두부 방사선 사진을 각기 2주 간격으로 촬영한 후 5개의 고경 계측항목과 9개의 폭경 계측항목을 선정하여 t 검정으로 각 계측항목의 재현도를 비교하는 한편, 정모와 측모 두부 방사선 사진으로3차원 상을 합성시 오차의 요인이 되는 두부의 상하회전 정도 차이를 촬영 방법별로 비교 분석하여 다음과 같은 결과를 얻었다. 1. 시간 간격을 두고 술자 유도법으로 2회 촬영한 정모 두부 방사선 사진의 계측치는 모든 고경 계측항목에서 서로 차이를 나타내어 낮은 재현도를 보였다. 2. 시간 간격을 두고 HPA법으로 2회 촬영한 정모 두부 방사선 사진의 계측치는 모든 고경 계측항목에서 통계적으로 유의한 차이를 나타내지 않아 재현도가 높음을 보였다. 3. 폭경 계측항목의 경우 2회 계측치의 차이를 통하여 살펴 본 재현도에서 술자유도법과HPA방법간에 두드러진 차이를 보이지 않았다. 4. 정모 및 측모 두부 방사선사진으로 3차원상을 합성하기 위한 수직적 두부 위치 보정각을 계산한 결과, 술자 유도법의 경우 $2.5^{\circ}$인 반면, HPA법은 $0.8^{\circ}$로 작게 나타났다. 이상의 결과는 정모 두부 방사선 규격 사진 촬영시 두부 위치의 재현도를 증가시키기 위하여 HPA의 사용이 필요함을 시사하였다.

• 한국방사선학회논문지
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• 제18권6호
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• pp.673-680
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• 2024

하지의 길이가 차이가 나는 방사선학적 검사 시 정확한 실측값을 측정할 수 있는 보조기구를 제작하여 수술계획 수립에 정확한 정량적인 값을 제공하는 데 연구의 목적이 있다. 기구 제작 후 높이와 길이 재현성 실험을 진행 후 측정값으로 정량적인 평가를 진행하였고 정형외과 전공의 10명을 대상으로 정성적 평가를 진행하여 유용성을 평가하였다. 높이 재현성 실험에서 기존한 방법은 1.0cm 실험을 제외한 모든 항목에서 p<0.05로 통계적으로 유의하였고 제작한 보조기구는 p≧0.05로 통계적으로 유의하지 않았다. 길이 재현성 실험에서 기존과 제작한 보조기구 방법 사이는 p<0.05로 두 방법은 통계적으로 유의한 차이를 보였다. 정성적 평가는 신뢰도 수치는 0.690이며 4.30 ± 0.94에서 4.90 ± 0.31의 범위 평균값을 도출하였다. 결론적으로 제작한 보조기구를 함께 이용하여서 하지 길이의 차이를 정량적인 값으로 나타내어 수술계획을 세운다면 수술 완성도에 높게 이바지할 수 있을 것으로 생각한다.

• Imaging Science in Dentistry
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• 제49권1호
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• pp.9-17
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• 2019

Purpose: This study aimed to introduce a novel method to evaluate the alveolar bone and interdental septum in the anterior mandible using cone-beam computed tomography (CBCT). Materials and Methods: Fifty-six CBCT scans from adult patients were selected. The CBCT scans were obtained before and after orthodontic treatment. The following measurements were taken: width of the alveolar bone and the interdental septum, height of the interdental septum, height of the bone plates, distance between the cementoenamel junction and marginal bone crests, and vertical positioning of the mandibular incisor, using the lingual plane as a reference. To test the reproducibility and the stability of the lingual plane, a triangle was traced in the anterior mandible. The intra-class correlation coefficient(ICC) was used to determine intra- and inter-examiner agreement. The paired Student t-test was used to evaluate the area of the triangle and the reproducibility of all measurements. Results: The ICC was excellent for the alveolar bone and dental measurements (0.9989 and 0.9977, respectively), as well as for the interdental septum (0.9987 and 0.9961, respectively). The area of the triangles showed stability in the lingual plane (P>0.05). For the alveolar bone, mandibular incisor, and interdental septum measurements, no statistically significant differences were found between the 2 examiners(P>0.05), confirming the technical reliability of the measurements. Conclusion: The method used in this study provides a valid and reproducible assessment of alveolar bone dimensions in the anterior mandible measured on CBCT images.

• 대한기계학회논문집
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• 제17권5호
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• pp.1132-1137
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• 1993

본 연구에서는 특수하게 제작된 펀치형상을 갖는 평면변형장출실험에 의한 스탬핑성형성 평가기술(RIST-PSST)의 개요에 대하여 논하고 돔장출 실험결과와 비교하여 본 방법의 특징을 검토하였다.

• Imaging Science in Dentistry
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• 제35권3호
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• pp.115-119
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• 2005

Purpose : To evaluate the magnification error percentage in repeatedly taken panoramic radiographs of same patient and machine. Materials and Methods : 92 panoramic radiographs from 46 patients were traced and 30 horizontal and vertical measurements were made with digital sliding caliper. The results were compared with paired t-test. Results : There was no statistically significant difference between the two measurements. The overall difference as percentage error was $6.19\pm5.60\%$. The largest error as $14.61\pm12.44\%$ was found at condylar height 1, and smallest as $1.86\pm1.61\%$ at mandibular height. Overall vertical error excluding condylar height 1 was $3.76\pm3.97\%$, and the horizontal error $6.88\pm5.92\%$. Conclusion . Repeatedly taken panoramic radiographs of the same patient and machine was reliable since there was no significant percentage error difference but the percentage error ranged from $1.86\pm1.61\%\;to\;14.61\pm12.44\%$ indicating the error depends on the measuring site.

• Journal of Preventive Medicine and Public Health
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• 제43권5호
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• pp.396-402
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• 2010

Objectives: Self-reported anthropometric values, such as height and weight, are used to calculate body mass index (BMI) and assess the prevalence of obesity among adolescents. The aim of this study was to evaluate the validity of selfreported height, weight, and BMI of the Korea Youth Risk Behavior Web-based Survey questionnaire. Methods: A convenience sample of 137 middle school students and 242 high school students completed a selfadministered questionnaire in 2008. Body height and weight were directly measured after self-reported values were obtained from the questionnaire survey. Sensitivity, specificity, and kappa statistics were computed in order to evaluate the validity of the prevalence of obesity (BMI $\geq$ 95th percentile or $\geq$ $25;kg/$m^2$) based on self-reported data. Results: Self-reported weight and BMI tended to be underestimated. Self-reported height tended to be overestimated among middle school females and high school males. Obese adolescents tended to underestimate their weight and BMI and overestimate their height more than non-obese adolescents. The prevalence estimate of obesity based on selfreported data (10.6%) was lower than that based on directly measured data (15.3%). The estimated sensitivity of obesity based on self-reported data was 69.0% and the specificity was 100.0%. The value of kappa was 0.79 (95% confidence interval, 0.70 - 0.88). Conclusions: This study demonstrated that self-reported height and weight may lead to the underestimation of BMI and consequently the prevalence of obesity. These biases should be taken into account when self-reported data are used for monitoring the prevalence and trends of obesity among adolescents nationwide.

• 대한기계학회논문집
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• 제17권11호
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• pp.2676-2683
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• 1993

Plane strain punch stretching test(PSST) was performed for various automotive steel sheets. To clarify the effect of tensile properties on plane strain stretchability, the limiting punch height(LPH) values were obtained in plane strain punch stretching test and related to the tensile properties of the materials. The results show that the total elongation El and work hardening exponent n compared to other parameters obtained from tensile test well correlate with the LPH value. In comparision with the Erichsen test and LDH test the PSST can be statistically used as an alternative in assessing the stamping formability of automotive steel sheets with the advantages of good reproducibility and easy testing method.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권1호
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• pp.17-25
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• 2012

Purpose: Recently, a three dimensional approach to hard and soft tissues of the maxillofacial area has been widely used. This study was to evaluate the reproducibility and accuracy of a stereocamera compared to actual measurement methods using a digital caliper and digitizer. Methods: The stereoscopies of 7 head dummies with different sizes and shapes were obtained using a Di3D system (Dimensional Imaging, Glasgow, UK) after marking reference points on facial areas. From the obtained stereoscopy, 10 measurements representing the width, height and depth of each of the facial sections of the dummy were measured twice using a three dimensional reverse engineering software program (RapidForm$^{TM}$ 2006, Inus, Seoul, Korea). The x, y, and z coordinates of each of the three dimensional measurements were obtained and distances between two points were calculated. All procedures were repeated twice. The actual measurement method was performed twice, directly on dummies, using a digital caliper and values were compared with the previously determined values. Results: The results were as follows. In the ANOVA analysis, there were no significant statistical differences among the three measurement methods. In the Bonferroni analysis, with adjustments applied for multiple comparisons, there was no difference between actual measurement methods using a digitizer and a digital caliper. However, there was some difference between using a stereocamera and actual measurement methods using a digitizer and a digital caliper in values of $Ex_{Rt}-Ex_{Lt}$, $En_{Rt}-En_{Lt}$, $Ala_{Rt}-Ala_{Lt}$, $Ch_{Rt}-Ch_{Lt}$, G-Pg', $Ala_{Rt}$-Prn, $Ala_{Rt}$-Prn. The mean value for technical error in measurement (TEM) in Di3D (0.98 mm) was slightly higher than for a digital caliper (0.17 mm) and a digitizer (0.30 mm). In an intraclass correlation coefficient (ICC) there were no significant differences among the three measurement methods, but the Di3D system with the stereocamera showed relatively lower reproducibility compared to actual measurement methods using a digitizer and a digital caliper. Conclusion: These results indicate that some complementary measures may be needed to improve accuracy and reproducibility in the Di3D system with stereocamera.

• 한국해안·해양공학회논문집
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• 제34권6호
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• pp.177-187
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• 2022

본 연구는 2020년 해양수산부에서 제시한 개정된 천해설계파 추산방법인 바람장을 이용하여 부산항 신항을 대상으로 태풍 내습 시 설계파를 추산하고 파랑 관측자료와의 검증을 통해서 신뢰할 수 있는 천해설계파 산출방법을 제안하였다. 부산항 신항에 영향을 미친 태풍에 대해서 현업에서 일반적으로 많이 사용하고 있는 태풍 바람장과 SWAN 수치모델을 이용하여 태풍파를 추산한 결과 태풍 KONG-REY(1825), MAYSAK(2009)을 제외하고 재현성이 불량한 것으로 나타났다. 특히 부산항 신항에 가장 크게 영향을 미쳤던 태풍 MAEMI(0314)의 경우 최대유의 파고가 파랑 관측치에 비해서 약 35.0% 작게 추산되었다. 이에 바람장을 보정한 방법과 Boussinesq 방정식 수치모델을 이용하는 방법을 각각 적용하여 태풍파 재현성 개선방안을 검토하였다. 검토결과 바람장을 보정한 경우는 바람장 보정전과 동일하게 재현성이 떨어지는 것으로 나타났으나, 바람장 자료와 SWAN 모델 실험결과 그리고 Bou ssinesq 수치모델을 연계하는 방법으로 태풍 MAEMI(0314) 내습 시 태풍파를 추산한 결과 파랑 관측치와 최대유의파고가 유사하게 나타나 재현성이 양호한 것으로 검토되었다.