• Journal of Biosystems Engineering
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• v.33 no.5
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• pp.317-325
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• 2008

The electrocardiogram (ECG) measurement system consists of I/O interface to input the ECG signals from two electrodes, FPGA (Field programmable gate arrays) module to process the signal conditioning, and real time module to control the system. The algorithms based on wavelet transform were developed to remove the noise of the ECG signals and to determine the QRS-waves. Triangular wave tests were conducted to determine the optimal factors of the wavelet filter by analyzing the SNRs (signal to noise ratios) and RMSEs (root mean square errors). The hybrid rule, soft method, and symlets of order 5 were selected as thresholding rule, thresholding method, and mother wavelet, respectively. The developed wavelet filter showed good performance to remove the noise of the triangular waves with 10.98 dB of SNR and 0.140 mV of RMSE. The ECG signals from a total of 6 subjects were measured at different measuring postures such as lying, sitting, and standing. The durations of QRS-waves, the amplitudes of R-waves, the intervals of RR-waves were analyzed by using the finite impulse response (FIR) filter and the developed wavelet filter. The wavelet filter showed good performance to determine the features of QRS-waves, but the FIR filter had some problems to detect the peaks of Q and S waves. The measuring postures affected accuracy and precision of the ECG signals. The noises of the ECG signals were increased due to the movement of the subject during measurement. The results showed that the wavelet filter was a useful tool to remove the noise of the ECG signals and to determine the features of the QRS-waves.

• Spatial Information Research
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• v.7 no.1
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• pp.63-79
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• 1999

In this research, the operational principle and the internal algorithm of theodolite measuring systems are studied and coded for a new software, and the feasibility of the laser system for the above mentioned usage is studied by simulation set-up of the system in the laboratory environment, and for the theodolite system modules for the communication between theodolite and computer is implemented, the data collection and storage, the simultaneous photogrammetric ' bundle ' adjustment for the theodolite position and the target points are coded, compiled and tested. for the simulation set-up of the laser system extensive studies on laser sources and laser detectors are performed, the system composition for the system simulation in the laboratory environment is studied and implemented, and the beam fluctuation due to the environmental changes in the course of the laser beam, such as changes in current of wind or in temperature is experimented. According to Experiment on the Source of 17 meters interval and the Detector, Laser beam is almost doesn't depend on air How, but it is effected by variations of temperature and light. Selecting cloudy day and time without change of temperature, it was realized that it is possible to perform deformation measurement more than approximately 2mm precision.precision.

• Journal of the Ergonomics Society of Korea
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• v.29 no.1
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• pp.113-120
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• 2010

This research is to evaluate the arousal level by using cardiovascular response. PPG was used in this study as one of the method of measuring it rather than ECG (Electrocardiography) for the purpose of solving ergonomic problem of sensing. The participants were in the age group of 20 (mean=24, standard deviation=1.25): five men and five women. Each experiment composed with four identical sets. First, a black screen was displayed for 30 second rest. Then, the prepared 6 pair images were randomly presented for 10 second stimulation and for 30 second non-stimulation. PPG was measured on the earlobes of experimenters at 200Hz sampling frequency. PPG amplitude, PPI(Pulse to Pulse Interval), and PRV(Pulse Rate Variability) were analyzed according to arousal level. T-test was performed to compare between the PPG variables of rest and relaxation, rest and arousal, and relaxation and arousal. Relative to the rest state, PPG amplitude decreased in relaxed state and increased in aroused state. Relative to the rest state, PPI decreased in both emotional states. However, more significant decline was observed in aroused state. PRV's LF and HF were used in the form of LF/HF to compare between the relaxed and the aroused state. Therefore, PPG signal showed significant differences between relaxed and aroused state. In conclusion, evaluation of human arousal level used in the PPG analysis demonstrated that PPG has better usability and comforter measurement than ECG and is clearly an alternative method of measuring arousal level.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.193-196
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• 2008

The vortical structures in a turbulent boundary layer (TBL) developed over a flat plate have been investigated experimentally. The flow conditions tested in this study were Re$_{\theta}$ = 3700, Re$_{\delta}$ = 11${\times}$105 and the shape factor H = 1.3. Instantaneous velocity fields in the streamwise-wall-normal planes were measured by using a dynamic PIV system. A trip-wire and sandpapers were placed behind the leading edge to promote the turbulent transition. 1000 velocity fields were obtained consecutively with a time interval of 1 millisecond. Streamwise u-velocity components were temporally averaged in the measuring plane. In addition, 2000 velocity fields were obtained randomly and ensemble-averaged to get the fully-developed turbulent characteristics. Profiles of the normalized u-component, turbulent intensities and Reynolds shear stress were evaluated. The structures of spanwise vortices were extracted from the instantaneous velocity fields by determining the swirling strength, ${\lambda}_{ci}$. The wall-normalized locations of vortices were temporally averaged in the measuring plane with respect to their rotational direction. The correlations between the temporally averaged u and the temporally averaged $y^+$ of vortices were evaluated. For the case of positive vortices, the correlation is not significant. However, the negative vortices show a strong negative correlation. The y-location of negative vortices tends to increase, as the averaged u decreases and vice versa. These findings indicate that the number of negative vortices in the outer layer increases during the outward bursting events.

• The Journal of Korean Physical Therapy
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• v.23 no.4
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• pp.59-66
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• 2011

Purpose: The objective of this study was to evaluate the inter- and intra-examiner reliability of ultrasonography (US) for measuring the thicknesses and cross-sectional area of the longus colli muscle (LCM) in healthy subjects. Methods: Twenty-five healthy adults participated in this study as subjects and two examiners attended to the study. LCM size was measured at the level of the thyroid cartilage. All subjects were randomly allocated to one of the three different methods. Method 1 was that the examiner A conducts the first measurement and one hour later conducts the second measurement and twenty four hours later conducts the third measurement, respectively. Method 2 was that the examiner B conducts the measurements in the same way as the examiner A. Method 3 was that the examiners A and B randomly conduct the measurements twice at an interval of one hour. Results: The intra-class correlation coefficient (ICC) for the intra-examiner reliability ranged from 0.78 to 0.98 at rest and 0.57 to 0.98 during contraction for the examiner A. The $ICC_{3,3}$ for the intra-examiner reliability ranged from 0.60 to 0.96 at rest and 0.57 to 0.92 during contraction for the examiner B. The $ICC_{2,3}$ for the inter-examiner reliability ranged from 0.80 to 0.91 at rest and 0.84 to 0.93 during contraction. Conclusion: The findings of this study indicate that US is a reliable method for measuring the LCM size.

• Journal of Biomedical Engineering Research
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• v.37 no.3
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• pp.105-111
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• 2016

Introduction: Surgical robot is the alternative instrument that substitutes the difficult and precise surgical operation; should have intuitiveness operationally to transfer natural motions. There are limitations of hand motion derived from contacting mechanical handle in the surgical robot master interface such as mechanical singularity, isotropy, coupling problems. In this paper, we will confirm and verify the feasibility of intuitive Non-restraint master interface which tracking the hand motion using infra-red camera and only 3 reflective markers without the hardware handle for the surgical robot master interface. Materials & methods: We configured S/W and H/W system; arranged 6 infra-red cameras and attached 3 reflective markers on hands for measuring 3 dimensional coordinate then we find the 7 motions of grasp, yaw, pitch, roll, px, py, pz. And we connected Virtual-Master to the slave surgical robot(Laparobot) and observed the feasibility. To verify the result of motion, we compare the result of Non-restraint master and that of clinometer (and protractor) through measuring 0~180 degree, 10degree interval, 1000 samples and recorded standard deviation stands for error rate of the value. Results: We confirmed that the average angle values of Non-restraint master interface is accurately corresponds to the result of clinometer (and protractor) and have low error rates during motion. Investigation & Conclusion: In this paper, we confirmed the feasibility and accuracy of 3D Non-restraint master interface that can offer the intuitive motion of non-contact hardware handle. As a result, we can expect the high intuitiveness, dexterousness of surgical robot.

• Korean Journal of Health Education and Promotion
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• v.20 no.1
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• pp.19-39
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• 2003

Purpose: Although there is a lot of secondary data available for comparing community health status and planning health policies in terms of large area such as metropolitan cities or provinces, there is restricted data for establishing community health policies of the small areas such as towns, Gun(i.e., districts), and Gu. Specifically, the problems of producing a valuable index for health promotion in small areas are three fold: First, there is not an appropriate index model for measuring a small community health status. Second, a large part of secondary data in the small areas has been produced in an irregular time interval. In addition, all valuable data can not be integrated without time consuming work. Thus this study tries to establish a health promotion index model for assisting community health promotion initiatives of local governments. Methods and materials: Literature review, community health specialist consultation and a questionnaire survey was performed. Results: Based on Dever's model, a prototype of health promotion indicators was proposed and modified by the community health specialists. 15 classification scheme of statistical yearbook reorganized into the six areas. Those six areas were comprised in 24 indicator class with 96 specific indicators. Through further modification processes by a questionnaire survey, we developed a health promotion indicator model that contains six areas with 23 indicator class encompassed by 87 specific indicators. Conclusions: This study proposed a model of health promotion indicator comprised in the six areas with 23 indicator classes for measuring small area health promotion status. However, more specific or additional data in human biology, environment, and socioeconomic data is essential for producing a stronger model for health promotion measurement.

• The World Journal of Men's Health
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• v.34 no.2
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• pp.137-144
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• 2016

Purpose: We compared a transperineal ligation model and a transperitoneal ligation model in male rats to determine which animal model of overactive bladder (OAB) was more useful based on cystometrography, estimations of oxidative stress, and measurements of pro-inflammatory cytokine levels. Materials and Methods: Male rats were randomly divided into three groups (n=15 in each): the control group, the transperineal ligation group, and the transperitoneal ligation group. Four weeks after the ligation procedure, cystometrography was performed and oxidative stress, pro-inflammatory cytokine levels, and histologic changes were evaluated. Oxidative stress was assessed by measuring 8-hydroxy-20-deoxyguanosine and superoxide dismutase, and pro-inflammatory cytokine activity was investigated by measuring levels of interleukin (IL)-6, IL-8, and tumor necrosis $factor-{\alpha}$. Results: The transperineal model led to results similar to those observed for the transperitoneal model, namely (1) increased voiding frequency and reductions in the non-voiding contraction interval and the maximal vesical pressure, (2) increased levels of oxidative stress markers, (3) increased pro-inflammatory cytokine levels, and (4) fibrotic changes in the bladder tissue. Conclusions: We suggest that the transperineal procedure can be used as an alternative OAB model in male rats.

• Phonetics and Speech Sciences
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• v.12 no.4
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• pp.73-80
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• 2020

In this study, a method for measuring the jitter component in continuous speech is presented. In the conventional jitter measurement method, pitch variabilities are commonly measured from the sustained vowels. In the case of continuous speech, such as a spoken sentence, distortion occurs with the existing measurement method owing to the influence of prosody information according to the sentence. Therefore, we propose a method to reduce the pitch fluctuations of prosody information in continuous speech. To remove this pitch fluctuation component, a curve representing the fluctuation is obtained via polynomial interpolation for the pitch track in the analysis interval, and the shift is removed according to the curve. Subsequently, the variability of the pitch frequency is obtained by a method of measuring jitter from the trajectory of the pitch from which the shift is removed. To measure the effects of the proposed method, parameter values before and after the operations are compared using samples from the Kay Pentax MEEI database. The statistical analysis of the experimental results showed that jitter components from the continuous speech can be measured effectively by proposed method and the values are comparable to the parameters of sustained vowel from the same speaker.

• Korean Journal of Radiology
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• v.20 no.6
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• pp.880-893
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• 2019

Objective: To assess the technical performance of two-dimensional shear wave elastography (2D-SWE) for measuring liver stiffness. Materials and Methods: The Ovid-MEDLINE and EMBASE databases were searched for studies reporting the technical performance of 2D-SWE, including concerns with technical failures, unreliable measurements, interobserver reliability, and/or intraobserver reliability, published until June 30, 2018. The pooled proportion of technical failure and unreliable measurements was calculated using meta-analytic pooling via the random-effects model and inverse variance method for calculating weights. Subgroup analyses were performed to explore potential causes of heterogeneity. The pooled intraclass correlation coefficients (ICCs) for interobserver and intraobserver reliability were calculated using the Hedges-Olkin method with Fisher's Z transformation of the correlation coefficient. Results: The search yielded 34 articles. From 20 2D-SWE studies including 6196 patients, the pooled proportion of technical failure was 2.3% (95% confidence interval [CI], 1.3-3.9%). The pooled proportion of unreliable measurements from 20 studies including 6961 patients was 7.5% (95% CI, 4.7-11.7%). In the subgroup analyses, studies conducting more than three measurements showed fewer unreliable measurements than did those with three measurements or less, but no intergroup difference was found in technical failure. The pooled ICCs for interobserver reliability (from 10 studies including 517 patients) and intraobserver reliability (from 7 studies including 679 patients) were 0.87 (95% CI, 0.82-0.90) and 0.93 (95% CI, 0.89-0.95), respectively, suggesting good to excellent reliability. Conclusion: 2D-SWE shows good technical performance for assessing liver stiffness, with high technical success and reliability. Future studies should establish the quality criteria and optimal number of measurements.