• Title/Summary/Keyword: Repeatability

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Repeatability and reproducibility of individual abutment impression, assessed with a blue light scanner

  • Jeon, Jin-Hun;Kim, Dong-Yeon;Lee, Jae-Jun;Kim, Ji-Hwan;Kim, Woong-Chul
    • The Journal of Advanced Prosthodontics
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    • v.8 no.3
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    • pp.214-218
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    • 2016
  • PURPOSE. We assessed the repeatability and reproducibility of abutment teeth dental impressions, digitized with a blue light scanner, by comparing the discrepancies in repeatability and reproducibility values for different types of abutment teeth. MATERIALS AND METHODS. To evaluate repeatability, impressions of the canine, first premolar, and first molar, prepared for ceramic crowns, were repeatedly scanned to acquire 5 sets of 3-dimensional data via stereolithography (STL) files. Point clouds were compared and the error sizes were measured (n=10, per type). To evaluate reproducibility, the impressions were rotated by $10-20^{\circ}$ on the table and scanned. These data were compared to the first STL data and the error sizes were measured (n=5, per type). One-way analysis of variance was used to assess the repeatability and reproducibility of the 3 types of teeth, and Tukey honest significant differences (HSD) multiple comparison test was used for post hoc comparisons (${\alpha}=.05$). RESULTS. The differences with regard to repeatability were 4.5, 2.7, and $3.1{\mu}m$ for the canine, premolar, and molar, indicating the poorest repeatability for the canine (P<.001). For reproducibility, the differences were 6.6, 5.8, and $11.0{\mu}m$ indicating the poorest reproducibility for the molar (P=.007). CONCLUSION. Our results indicated that impressions of individual abutment teeth, digitized with a blue light scanner, had good repeatability and reproducibility.

Repeatability of a Multi-segment Foot Model with a 15-Marker Set in Normal Children

  • Kim, Eo Jin;Shin, Hyuk Soo;Lee, Jae Hee;Kyung, Min Gyu;Yoo, Hyo Jeong;Yoo, Won Joon;Lee, Dong Yeon
    • Clinics in Orthopedic Surgery
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    • v.10 no.4
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    • pp.484-490
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    • 2018
  • Background: The use of three-dimensional multi-segment foot models (3D MFMs) is increasing since they have superior ability to illustrate the effect of foot and ankle pathologies on intersegmental motion of the foot compared to single-segment foot model gait analysis. However, validation of the repeatability of the 3D MFMs is important for their clinical use. Although many MFMs have been validated in normal adults, research on MFM repeatability in children is lacking. The purpose of this study is to validate the intrasession, intersession, and interrater repeatability of an MFM with a 15-marker set (DuPont foot model) in healthy children. Methods: The study included 20 feet of 20 healthy children (10 boys and 10 girls). We divided the participants into two groups of 10 each. One group was tested by the same operator in each test (intersession analysis), while the other group was tested by a different operator in each test (interrater analysis). The multiple correlation coefficient (CMC) and intraclass correlation coefficient (ICC) were calculated to assess repeatability. The difference between the two sessions of each group was assessed at each time point of gait cycle. Results: The intrasession CMC and ICC values of all parameters showed excellent or very good repeatability. The intersession CMC of many parameters showed good or better repeatability. Interrater CMC and ICC values were generally lower for all parameters than intrasession and intersession. The mean gaps of all parameters were generally similar to those of the previous study. Conclusions: We demonstrated that 3D MFM using a 15-marker set had high intrasession, intersession, and interrater repeatability in the assessment of foot motion in healthy children but recommend some caution in interpreting the hindfoot parameters.

Mini-Review of Studies Reporting the Repeatability and Reproducibility of Diffusion Tensor Imaging

  • Seo, Jeong Pyo;Kwon, Young Hyeon;Jang, Sung Ho
    • Investigative Magnetic Resonance Imaging
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    • v.23 no.1
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    • pp.26-33
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    • 2019
  • Purpose: Diffusion tensor imaging (DTI) data must be analyzed by an analyzer after data processing. Hence, the analyzed data of DTI might depend on the analyzer, making it a major limitation. This paper reviewed previous DTI studies reporting the repeatability and reproducibility of data from the corticospinal tract (CST), one of the most actively researched neural tracts on this topic. Materials and Methods: Relevant studies published between January 1990 and December 2018 were identified by searching PubMed, Google Scholar, and MEDLINE electronic databases using the following keywords: DTI, diffusion tensor tractography, reliability, repeatability, reproducibility, and CST. As a result, 15 studies were selected. Results: Measurements of the CSTs using region of interest methods on 2-dimensional DTI images generally showed excellent repeatability and reproducibility of more than 0.8 but high variability (0.29 to 1.00) between studies. In contrast, measurements of the CST using the 3-dimensional DTT method not only revealed excellent repeatability and reproducibility of more than 0.9 but also low variability (repeatability, 0.88 to 1.00; reproducibility, 0.82 to 0.99) between studies. Conclusion: Both 2-dimensional DTI and 3-dimensional DTT methods appeared to be reliable for measuring the CST but the 3-dimensional DTT method appeared to be more reliable.

Comparative evaluation of repeatability of scanning abutment tooth stone model and impression : Applied assessment of CAD/CAM ISO standard in dentistry (치과 캐드캠 ISO평가 기준에 준한 지대치 경석고 모형 및 인상체 스캐닝의 반복측정안정성 비교 평가)

  • Jeon, Jin-Hun;Hwang, Seong-Sig;Kim, Chong-Myeong;Kim, Dong-Yeon;Kim, Ji-Hwan;Kim, Woong-Chul
    • Journal of Technologic Dentistry
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    • v.39 no.1
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    • pp.1-7
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    • 2017
  • Purpose: The purpose of this in vitro study compared to evaluation of repeatability of scanning abutment tooth stone model and impression applied CAD/CAM ISO standard in dentistry. Methods: To evaluate repeatability of scanning abutment tooth stone model, were repeatedly scanned to obtain 11 data via 3D stereolithography (STL) files. 10 data (STL files) were compared with the first 3D data (STL file), and the error sizes were measured by using 3D superimposing software(n=10). Also, the repeatability of scanning abutment tooth impression was evaluated with the same procedure. Independent t test was performed to evaluate the repeatability of scanning abutment tooth stone model versus impression through root mean square(RMS) and standard deviation(SD)(${\alpha}=0.05$). Results: $RMS{\pm}SD$ with regard to repeatability were $14.7{\pm}2.5{\mu}m$, $17.1{\pm}4.0{\mu}m$, respectively, with scanning abutment tooth stone model and impression(p=0.129). Conclusion: This study results showed a little different repeatability of scanning abutment tooth stone model and impression applied CAD/CAM ISO standard in dentistry, will suggest futures good studies and clinical advantages.

Evaluation of the effect of abutment preparation angles on the repeatability and reproducibility using a blue light model scanner

  • Kim, Dong-Yeon
    • The Journal of Advanced Prosthodontics
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    • v.12 no.4
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    • pp.210-217
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    • 2020
  • PURPOSE. The purpose of the study is to evaluate the repeatability and reproducibility of the abutment angle using a blue light scanner. MATERIALS AND METHODS. 0°, 6°, and 10° wax cast abutment dies were fabricated. Each of the silicone impression was produced using the replicable silicone. Each study die was constructed from the prepared replicable stone used for scans. 3-dimensional data was obtained after scanning the prepared study dies for the repeatability by using the blue light scanner. The prepared 3-dimensional data could have the best fit alignment using 3-dimensional software. For reproducibility, each abutment was used as the first reference study die, and then it was scanned five times per each. 3-dimensional software was used to perform the best fit alignment. The data obtained were analyzed using a nonparametric Kruskal-Wallis H test (α=.05), post hoc Mann-Whitney U test, and Bonferroni correction (α=.017). RESULTS. The repeatability of 0°, 6°, and 10° abutments was 3.9, 4.4 and 4.7 ㎛, respectively. Among them, the 0° abutment had the best value while the 10° abutment showed the worst value. There was a statistically significant difference (P<.05). The reproducibility of 0°, 6°, and 10° abutments was 6.1, 5.5, and 5.3 ㎛, respectively. While the 10° abutment showed the best value, the 0° abutment showed the worst value. However, there was no statistically significant difference (P>.05). CONCLUSION. In repeatability, the 0° abutment showed a positive result. In reproducibility, the 10° abutment achieved a positive result.

A Clinical Study on the Repeatability and Reproducibility of Ryodoraku Score (양도락의 반복성, 재현성에 관한 임상적 연구)

  • Cha, Jae-Hoon;Kim, Yoon-Bum;Shin, Yoon-Jin;Kim, Jin-Myoung
    • The Journal of Korean Medicine
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    • v.30 no.1
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    • pp.76-82
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    • 2009
  • Objectives: Ryodoraku diagnosis has been used frequently since Nakatani invented it in 1950. There are many papers about how to use Ryodoraku diagnosis in many diseases, but there are no studies about the repeatability and reproducibility of the Ryodoraku score. The aim of this study was to investigate the repeatability and reproducibility of the Ryodoraku score. Materials and Methods: There were four examiners who trained for more than a month, and the number of subjects was twenty. Each of the examiners made Ryodoraku diagnosis for ten subjects three times. We analyzed data by SPSS, used Friedman test, Wilcoxon signer rank test and Spearman correlation test. Results: 1. There was no significant difference between first, second, and third Ryodoraku score by Friedman test in examiners A, B, C, and D, so there was repeatability. 2. There was very high correlation on first, second, third Ryodoraku score by Spearman correlation test in examiners A, B, C, and 0, so there was repeatability. 3. There was high ICC among Ryodoraku score by examiners B, C, and D, so there was reproducibility. 4. After observing four examiners' Ryodoraku diagnoses, we could see the discord of measure points, the amount of hydration before examination, the amount of pressure, examination time, or positions of subjects diagnosed with Ryodoraku incorrectly. Conclusion: There is repeatability and reproducibility of Ryodoraku diagnosis. However, it is still important that one examiner carry out the diagnosis if possible. When there are two or more examiners, they should train extensively and follow manuals.

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Repeatability of a Semi-quantitative Food Frequency Questionnaire or the Korean Elderly (한국노인을 위한 반정량적 식품섭취빈도조사지의 신뢰도 검증)

  • 오세영;홍명희
    • Journal of Nutrition and Health
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    • v.31 no.7
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    • pp.1183-1191
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    • 1998
  • In order to evaluate the repeatability of nutrient values estimated from a semiquantitative food frequency questionnaire(SFFQ) for elderly Korean, a sample of 100 participants(45 men, 55 women) were interviewed to complete a SFFQ developed by this study twice at an approximately 3 month interval. The mean age of subjects was 70.4 years. Males(mein=8.75 years) had more education thu females(1.4 years). In males, Nutrient values calculated from the repeat questionnaire were not significantly different from the baseline results by paired t test. Correlation coefficients of most nutrients ranged from 0.4-0.6. For most nutrients,60-73% males classified into the lowest tertile in baseline data belonged to the same tertile in a repeat questionnaire, but these values appeared to be less than 50% for females. These results were comparable to previously published results and confirm that repeatability of nutrient intakes estimated using SFFQs was acceptable. The repeatability of SFFQ was higher for males than females, which implies that years of schooling should be considered in the development of SFFQ for the elderly. Only f3r males, Mean Adequacy Ratio(MAR) of nutrient intake was higher for those who were less nutritionally at risk and less depressed, and physically functioned better. Considering the educational level of the Korean elderly overall, more studies on the development of simpler dietary assessment methods f3r this population are needed.(Korean J Nutrition 31(7) : 1183-1191, 1998)

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Repeatability and Reliability of a New Phoria Test Using Flashed and Auto-flashed Presentation

  • Moon, Byeong-Yeon;Park, Sun-Young;Cho, Hyun Gug
    • Journal of the Optical Society of Korea
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    • v.16 no.4
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    • pp.418-424
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    • 2012
  • The purpose of this study was to assess repeatability and reliability of a new phoria test as compared to established phoria tests and to assess the possibility of mobile or online testing using the auto-flashed presentation. Near dissociated phoria was measured using the von Graefe method, the Howell card test, the modified Thorington test, and a new dichromatic card test (Red-Blue Phoria card test; RBP card test) on 109 subjects. The inter-examiner difference and test-retest difference were calculated. With the auto-flashed presentation of the RBP card test, near dissociated phoria was measured and the intraclass correlation coefficient and test-retest repeatability was assessed on 26 subjects. The variation in inter-examiner repeatability was the smallest for the modified Thorington test (+3.1/-2.6). The RBP card test was +3.0/-3.1, the Howell card test was +3.5/-2.7, and the von Graefe test was +6.2/-6.0. The variation in test-retest repeatability was the smallest for the RBP card test (+0.4/-1.4). The modified Thorington test was +1.3/-1.3, the Howell card test was +1.27/-1.45, and the von Graefe test was +1.59/-2.20. The ICC was 0.919 for the auto-flashed presentation of the RBP card test. The RBP card test is considered a highly repeatable method clinically and can be made a useful application for testing in mobile or online.

Measurement Uncertainty Estimation of Injection Temperature in Injection Molding Machine (사출성형기의 사출온도에 대한 측정 불확도 추정)

  • Jung, Hyun-Suk;Yoo, Joong-Hak
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.1
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    • pp.145-149
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    • 2013
  • The performance of injection molding machine's control system, such as reproducibility, repeatability, etc, is widely studied nowadays. Since screw stroke, injection cylinder body pressure and barrel temperature are the most important terms of injection unit, interval linearity and repeatability to each parameter are analyzed here. Barrel temperature is analyzed according to the repeatability of the thermocouple at $150^{\circ}C$, $210^{\circ}C$, $300^{\circ}C$ using a precise oven. The result temperature is within ${\pm}0.5^{\circ}C$ Through the reliability evaluation of the most important terms of injection unit, the method of evaluating the linearity and repeatability is proposed and verified.

The Development of an Inverse Kinematic Solution for Periodic Motion of a Redundant Manipulator (여유자유도 로봇의 주기적 운동제어를 위한 역기구학 해의 개발)

  • 정용섭;최용제
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.1
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    • pp.142-149
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    • 1995
  • This paper presents a new kinematic control strategy for serial redundant manipulators which gives repeatability in the joint space when the end-effector undergoes some general cyclic motions. Theoretical development has been accomplished by deriving a new inverse kinematic equation that is based on springs being conceptually located in the joints of the manipulator. Although some inverse kinematic equations for serial redundant manipulators have been derived by many researchers, the new strategy is the first to include the free angles of torsional springs and the free lengths of the translational springs. This is important because it ensures repeatability in the joint space of a serial redundant manipulator whose end-effector undergoes a cyclic type motion. Numerical verification for repeatability is done in terms of Lie Bracket Condition. Choices for the free angle and torsional stiffness of a joint (or the free length and translational stiffness) are made based upon the mechanical limits of the joints.