• Journal of Acupuncture Research
• /
• v.31 no.1
• /
• pp.61-73
• /
• 2014

Objectives : The purpose of this study is to estimate the test-retest reliability and the intratest repeatability in measuring the lumbar range of motion of healthy volunteers with wireless microelectromechanical system inertial measurement unit(MEMS-IMU) system and to discuss the feasibility of this system in the clinical setting to evaluate the lumbar spine movement. Methods : 19 healthy male volunteers were participated, who got under 21 points at oswestry disability index(ODI) were adopted. Their lumbar motion were measured with IMU twice in consecutive an hour for the test-retest reliability study. Intratest repeatability was calculated in the two tests separately. The calculated intraclass correlation coefficients(ICC) were discussed and compared with the those of the previous studies. Results : Lumbar range of motion of flexion $41.45^{\circ}$, extension $16.34^{\circ}$, right lateral bending $16.41^{\circ}$ left lateral bending $13.63^{\circ}$ right rotation $-2.47^{\circ}$, left rotation $-0.61^{\circ}$. ICCs were 0.96~1.00(intratest repeatability) and 0.61~0.92(test-retest reliability). Conclusion : This study shows that MEMS-IMU system demonstrates a high test-retest reliability and intratest repeatability by calculated intraclass correlation coefficients. The results of this study represents that wireless inertial sensor measurement system has portable and economical efficiency. By MEMS-IMU system, we can measures lumbar range of motion and analyze lumbar motion effectively.

• Journal of Acupuncture Research
• /
• v.30 no.4
• /
• pp.25-33
• /
• 2013

Objectives : To assess the test-retest reliability and the intratest repeatability in measuring the cervical range of motion of healthy subjects with wireless microelectromechanical system inertial measurement unit(MEMS-IMU) system and to discuss the feasibility of this system in the clinical setting to evaluate the cervical spine musculoskeletal. Methods : 12 healthy people who were evaluated as no- or mild-disability with neck disability index were participated. Their cervical motion were measured with IMU twice in consecutive two days for the test-retest reliability study. Intratest repeatability was calculated in the two tests separately. The calculated intraclass correlation coefficients(ICC) were discussed and compared with the those of the previous studies. Results : Cervical range of motion data were acquired and statistically processed: left rotation($61.64^{\circ}$), right rotation($65.12^{\circ}$), extension($61.98^{\circ}$), flexion($52.81^{\circ}$), left bending($39.31^{\circ}$), right bending($41.08^{\circ}$). ICCs were 0.77~0.98(intratest repeatability) and 0.74~0.93 (test-retest reliability) in the primary motion. In the coupling motion, intratest repeatability ICCs were 0.93~ 0.99(transverse primary plane), 0.88~0.97(saggital primay plane), and 0.77~0.93(coronal primary plane). Test-retest reliability of coupling motion were 0.90~0.97(transverse primary plane), 0.00~0.72(saggital primary plane), and 0.04~0.76(coronal primary plane). Conclusions : Several types of range-of-motion devices are now on use in many fields including medicine, but the practicality of the devices in clinical use is questionable for the convenient and economical aspects. In this study, we presented the reliability of cervical range of motion test with the developed wireless MEMS-IMU system and discussed its potential utility in clinical use.

• The Journal of the Society of Korean Medicine Diagnostics
• /
• v.10 no.2
• /
• pp.88-103
• /
• 2006

Objectives : We performed this study to search the best time for HRV measuring and which index has the validity in a short term measuring. Methods : At first, three examiner measured electrocardiogram(ECG) of 5 people(4 male + 1 female) for 20 minutes in two times. and we devided ten regions (0-5, 5-10, 10-15, 15-20, 0-10, 0-15, 0-20, 5-15, 10-20, 5-20 minutes). After that we finded the HRV index for each regions. To evaluate the validity, we used Gage Repeatability and Reproducibility Study by MINITAB(ver. 13.20). If the '%Study Var' is under 30 and 'Number of Distinct Categories' is over 4, we could tell it has validity(repeatability and reproducibility). Results : 1) The region and HRV index has repeatability and reproducibility, was HF index in 10-15 minutes. The HF index in 15-20 minutes gained 27.41(%Study Var) and 5(Number of Distinct Categories). 2) The HF index in 10-15 minutes has the better reproducibility than repeatability. The value of measurement is under the control. There is consistency among the examiner. The distribution of measurement is not large. There is no interaction between examiner and each people. 3) The HF index in 10-15, 0-10, 0-15, 0-20, 10-20 minutes was not enough to gain the repeatability and reproducibility. But it had some meanings ; %Study Var, Number of Distinct Categories is 32.68, 4 for 10-15 minutes, 34.43, 4 for 0-10 minutes, 34.44, 4 for 0-15 minutes, 33.56, 4 for 0-20 minutes, 32.07, 4 for 10-20 minutes. Conclusions : This study shows the best index of measuring HRV is the HF index in 15-20 minutes. So, from now on we should measure the HRV for 20 minutes and extract the HF index in 15-20 minutes. It must be the standard for HRV measuring.

• The Journal of the Society of Korean Medicine Diagnostics
• /
• v.9 no.2
• /
• pp.123-144
• /
• 2005

Objectives: Pulse-Respiration Ratio has been used for estimating subject's Han-Yeol [寒熱] status since it mentioned in suwen [素問]. In practicing Pulse-Respiration Ratio over 5 means the status of Yeol [熱], Pulse-Respiration Ratio below 3 means the status of Han [寒]. We performed this study to examine the Optimum Standard for Measuring Pulse-Respiration Ratio on the Basis of Repeatability and Reproducibility. Methods: After subject's 5 minutes rest we measured subject's ECG, respiration pattern, EEG, EMG simultaneously. In this research examiner's number is two, subject's number is four, and the number of repeat is two. We calculated Pulse-Respiration Ratio through dividing Respiration cycle average by Pulse cycle average according to each standard including time section, $EEG(relative-{\alpha}$ density, $relative-{\beta}$ density, ${\alpha}/{\beta}$ and EMG. We analyzed these data through Gage R&R study using MINITAB 13.20 program and considered the results of below 30 %R&R and over 4 Number of Distinct Categories to have a significance. Results: 1. In the applying of time standard, Pulse-Respiration Ratio from section 3, 4, 6, 8 had a significant meaning in the aspect of Repeatability and Reproducibility. 2. In the applying of $EEG({\alpha}$ I , ${\beta}$ I , ${\alpha}/{\beta})$, EMG(E I) standard, there was no significant results. 3. In the applying of time standard(section 5, 6, 7), $EEG({\alpha}$ I , ${\beta}$ I , ${\alpha}/{\beta})$ and EMG(E I) standard simultaneously, Pulse-Respiration Ratio from ${\alpha}/{\beta}$ in section 6, ${\beta}$ I in section 8 had a significant meaning in the aspect of Repeatability and Reproducibility. Conclusions: We can suggest the Optimum Standard for Measuring Pulse-Respiration Ratio on the basis of Repeatability and Reproducibility as followings; 1. Pulse-Respiration Ratio Measuring time should be at least 15 minutes. 2. Applying of time(section 6, 8) and $EEG({\beta}$ I, ${\alpha}/{\beta})$ standard simultaneously is recommended considering reliability and validity but more study is needed. 3. EMG(E I) may be helpful to detect the segment of physical rest and exclude artifacts but more study is needed.

• Korean Journal of Ophthalmology
• /
• v.32 no.6
• /
• pp.506-516
• /
• 2018

Purpose: We measured the thicknesses of the ganglion cell and inner plexiform layer (GCIPL), the macula, and the retinal nerve fiber layer (RNFL) using spectral-domain optical coherence tomography in patients with idiopathic macula holes to analyze the repeatability of these measurements and compare them with those of the fellow eye. Methods: We evaluated 85 patients who visited our retinal clinic. The patients were divided into two groups according to their macular hole size: group A had a size of $<400{\mu}m$, while group B had a size of ${\geq}400{\mu}m$. Repeatability was determined by comparing the thicknesses of the GCIPL, macula, and RNFL with those of the normal fellow eye. Results: The average central macular thickness in patients with macular holes was significantly thicker than that in the normal fellow eye ($343.8{\pm}78.6$ vs. $252.6{\pm}62.3{\mu}m$, p < 0.001). The average thickness of the GCIPL in patients with macular holes was significantly thinner than that in the normal fellow eye ($56.1{\pm}23.4$ vs. $77.1{\pm}12.8{\mu}m$, p < 0.001). There was no significant difference in the average RNFL thickness between eyes with macular holes and fellow eyes ($92.4{\pm}10.0$ vs. $95.5{\pm}10.7{\mu}m$, p = 0.070). There were also no significant differences in the thicknesses of the GCIPL and RNFL among the two groups (p = 0.786 and p = 0.516). The intraclass correlation coefficients for the macula and RNFL were 0.994 and 0.974, respectively, in patients with macular holes, while that for the GCIPL was 0.700. Conclusions: Macular contour change with macular hole results in low repeatability and a tendency of thinner measurement regarding GCIPL thickness determined via spectral-domain optical coherence tomography. The impact of changes in the macular shape caused by macular holes should be taken into consideration when measuring the GCIPL thickness in patients with various eye diseases such as glaucoma and in those with neuro-ophthalmic disorders.

• Geophysics and Geophysical Exploration
• /
• v.15 no.4
• /
• pp.209-218
• /
• 2012

Repeatability and reproducibility in solid weight and effective porosity measurements have been discussed using 8 core samples with different diameters, lengths, rock types, and effective porosities. Further, the effect of temperature on the effective porosity measurement has been discussed as well. Effective porosity of each sample has been measured 7 times with vacuum saturation method with vacuum pressure of 1 torr and vacuum time of 80 minutes. Firstly, effective porosity of each sample is measured one by one, so that it can provide a reference value. Then for reproducibility check, effective porosity measurements with vacuum saturation of 2, 4, and 8 samples simultaneously have been performed. And finally, repeated measurements for 3 times for each sample are made for repeatability check. Average deviation from the reference set in solid weight showed 0.00 $g/cm^3$, which means perfect repeatability and reproducibility. For effective porosity, average deviations are less than 0.07% and 0.05% in repeatability and reproducibility test sets, respectively, which are in good agreement too. Most of porosities measured in reproducibility test lies within the deviation range in repeatability test sets. Thus, simultaneous vacuum saturation of several samples has little impact on the effective porosity measurement when high vacuum pressure of 1 torr is used. Air temperature can cause errors on submerged weight read and even effective porosity, because it is closely related to the temperature, density, and buoyancy of water. Consequently, for accurate measurement of effective porosity in a laboratory, efforts for maintaining air or water temperature constant during the experiment, or a temperature correction from other information are needed.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
• /
• 2001.06a
• /
• pp.4107-4107
• /
• 2001

Previous works have shown the viability of NIRS technology for the prediction of fatty acids in Iberian pig fat, but although the resulting equations showed high precision, in the predictions of new samples important fluctuations were detected, greater with the time passed from calibration development to NIRS analysis. This fact makes the use of NIRS calibrations in routine analysis difficult. Moreover, this problem only appears in products like fat, that show spectrums with very defined absorption peaks at some wavelengths. This circumstance causes a high sensibility to small changes of the instrument, which are not perceived with the normal checks. To avoid these inconveniences, the software WinISI 1.04 has a mathematic algorithm that consist of create a “Repeatability File”. This file is used during calibration development to minimize the variation sources that can affect the NIRS predictions. The objective of the current work is the evaluation of the use of a repeatability file in quantitative NIRS analysis of Iberian pig fat. A total of 188 samples of Iberian pig fat, produced by COVAP, were used. NIR data were recorded using a FOSS NIRSystems 6500 I spectrophotometer equipped with a spinning module. Samples were analysed by folded transmission, using two sample cells of 0.1mm pathlength and gold surface. High accuracy calibration equations were obtained, without and with repeatability file, to determine the content of six fatty acids: miristic (SECV$\sub$without/=0.07% r$^2$$\sub$without/=0.76 and SECV$\sub$with/=0.08% r$^2$$\sub$with/=0.65), Palmitic (SECV$\sub$without/=0.28 r$^2$$\sub$without/=0.97 and SECV$\sub$with/=0.24% r$^2$$\sub$with/=0.98), palmitoleic (SECV$\sub$without/=0.08 r$^2$$\sub$without/=0.94 and SECV$\sub$with/=0.09% r$^2$$\sub$with/=0.92), Stearic (SECV$\sub$without/=0.27 r$^2$$\sub$without/=0.97 and SECV$\sub$with/=0.29% r$^2$$\sub$with/=0.96), oleic (SECV$\sub$without/=0.20 r$^2$$\sub$without/=0.99 and SECV$\sub$with/=0.20% r$^2$$\sub$with/=0.99) and linoleic (SECV$\sub$without/=0.16 r$^2$$\sub$without/=0.98 and SECV$\sub$with/=0.16% r$^2$$\sub$with/=0.98). The use of a repeatability file like a tool to reduce the variation sources that can disturbed the prediction accuracy was very effective. Although in calibration results the differences are negligible, the effect caused by the repeatability file is appreciated mainly when are predicted new samples that are not in the calibration set and whose spectrum were recorded a long time after the equation development. In this case, bias values corresponding to fatty acids predictions were lower when the repeatability file was used: miristic (bias$\sub$without/=-0.05 and bias$\sub$with/=-0.04), Palmitic (bias$\sub$without/=-0.42 and bias$\sub$with/=-0.11), Palmitoleic (bias$\sub$without/=-0.03 and bias$\sub$with/=0.03), Stearic (bias$\sub$without/=0.47 and bias$\sub$with/=0.28), oleic (bias$\sub$without/=0.14 and bias$\sub$with/=-0.04) and linoleic (bias$\sub$without/=0.25 and bias$\sub$with/=-0.20).

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.1
• /
• pp.10-14
• /
• 2013

High precision machining technology has become one of the important parts in the development of a precision machine. Such a machine requires high precision positioning as well as high speed on a large workspace. For machining systems having a high precision positioning with a long stroke, it is necessary to examine the repeatability of reference position decision. Though ball-screw driven linear stages equipped linear scale have high precision feed drivers and a long stroke, they have some limitations for reference position decision if they have not equipped the accurate home sensor. This study is performed to experimentally examine the repeatability for home position decision of a magnetic sensor as a home switch of ball-screw driven linear stage by using capacitance probe.

• Journal of the Ergonomics Society of Korea
• /
• v.24 no.2
• /
• pp.45-49
• /
• 2005

The FSA(Force Sensitive Application) system measures hand force by using force resistance sensors. Compared to conventional hand force measurement systems such as Lafayette hand dynamometer and Jamar hydraulic hand dynamometer, the FSA system can be applied to analyze use of hand forces while the hand is manipulating objects for a task, However, the measurement performance of the FSA system has not been objectively evaluated. The present study tested the FSA system in terms of stability, repeatability, accuracy, and linearity. It is shown that the FSA system has good stability (CV$\leq$0.02) and linearity($R^2$=0.82), but has low repeatability(CV=$0.11{\sim}0.19$) and accuracy(22% of underevaluation on average). This performance result indicates that measurements from the FSA system should be used for relative comparison rather than for absolute comparison.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.2
• /
• pp.157-161
• /
• 2015

For machining systems having a high precision positioning with a long stroke, it is necessary to examine the repeatability of reference position decisions. Though ball-screw driven linear stages equipped with encoders have high precision feed drivers and a long stroke, they have some limitations for reference position decisions if they have not been equipped accurate home sensors. High precision machining technology has become one of the most important aspects of the development of a precision machine. Such a machine requires high precision positioning as well as high speed on a large workspace. This study is performed to experimentally compare the repeatability for home position decisions in the case of photo sensors and hall sensors as a home switch of the ball-screw driven linear stage.