• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.203-204
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• 1998

ECG analysis is main techniques for diagnosing heart disease. In recent, some studies have been performed about detection of QT interval. But, it's difficult to detect QT interval because T wave is evasive. In this paper, we have detected peak point and end point of T wave and calculated QT interval. And the result has been compared with the other algorithm after detection of QT interval.

• Journal of the Ergonomics Society of Korea
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• v.9 no.1
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• pp.3-14
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• 1990

This article develops a cost-effective and accurate measurement system for heart best intervals. The system is composed of an analog to digital (A/D) converter, an IBM personal computer (an 8088 microprocessor, an 8253-5 timer, an 8259A interrupt controller, and memories) and assembler programs for controlling these hardware components. An exponential smoothing algorithm effectively reduced noise effects from A/D converted electrocardiogram (ECG) signals influenced by 60 Hz alternating current (AC). The system can collect 15000 heart beat intervals with an 1/5400 second unit.

• Journal of Digital Convergence
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• v.18 no.7
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• pp.215-222
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• 2020

The aim of this study was to develop a mobile application 'Beat Processing Device (BPD)' to record and quantify the data for the performance accuracy of rhythm production. BPD has been developed in three phases. First, we reviewed studies that used rhythm as main intervention strategy to improve cognitive functioning of older adults, and derived four basic rhythm idioms. Second, we developed an iOS-based mobile application, optimized the device, the instrument tone, and the measurement variables through preliminary test. Lastly, we tested the mobile application by comparing the performance data obtained from MIDI and BPD from 60 older adults. The device was shown to be reliable and consistent with other mode of measurement and analysis. Conclusively, BPD can be a useful tool for assessing rhythm production ability in the course of cognitive skills training.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.6
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• pp.671-678
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• 2014

This paper presents a Ka-band FMCW sensor that has high linearity by improving a nonlinear behavior of the voltage controlled oscillator. Due to the nonlinear characteristics of the voltage controlled oscillator for the conventional method, the drift of beat frequency can cause inaccuracy and errors to the extracted results. A Ka-band FMCW signal with fast transition time could be generated by using both direct digital synthesizer and phase locked loop in this research. The implemented FMCW sensor showed very high accuracy in beat frequency through the test.

• The Korean Journal of Physiology
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• v.2 no.2
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• pp.45-52
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• 1968

Maximal oxygen uptake was measured in twenty-eight middle-aged men aged 45.0 (range: 40.3-50.7) years and fourteen middle-aged women aged 40.5 (range: 34.3-47.5) years by means of a treadmill test. The physique of subjects were:mean skinfold thickness at 4 sites, namely, back, arm, waist and abdomen was 7.59 mm in men and 14.5 mm in women; total body fat estimated from the mean skinfold thickness, 11.9% fat in men and 25.5% fat in women. The detailed observations are as follows: 1. Maximal oxygen uptake expressed on any reference unit in men was greater than that of women. The values of men to women were: 2.61 to 1.92l/min., 45.1 to 37.0 ml/min./kg, 51.8 to 46.5 ml/min./kg lean body mass (LBM), 15.7 to 12.6 ml/min./cm body height. 2. Maximal pulmonary ventilation in men was 80.2 l/min. and 63.5 l/min. in women. 3. There was a correlation of fairly high degree between maximal oxygen uptake and body weight, namely, r=0.56 in men and r=0.79 in women. The correlation between maximal oxygen uptake and lean body mass also was fairly high, namely, r=0.58 in men and r=0.69 in women. 4. The correlation between maximal pulmonary ventilation and body weight or lean body mass was r=0.51 and r=0.25 in middle-aged men and r=0.41 and r=0.19 in middle-aged women, respectively. 5. Maximal heart rate in men was 176.4 beat/min. and it was 183.9 beat/min. in women. 6. Maximal oxygen pulse in men was 14.6 ml/beat and 9.5 ml/beat in women. 7. Aerobic work capacity of korean middle-aged men and women maintained the same level as that of young men and women, respectively, as shown by maximal oxygen uptake expressed ml/min./kg or ml/min./kg lean body mass.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.339-344
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• 2000

The mucociliary system is one of the most important airway defense mechanisms in human body and impairment of ciliary movement results in various diseases in respiratory tract. In this study, we have developed a system that can measure ciliary movement in vivo and quantified ciliary beat frequency (CBF) through autoregressive (AR) power spectrum. To measure the frequency in vivo, we applied a photoelectric method that was composed of a laser light and a fiber optic probe. Scattered signals are transferred to a PC in which they are displayed on the monitor and its CBF is determined by the AR method in were acquired. For 8 normal subjects, the analyzed CBFs ranged from 5 to 10Hz and its mean was 7.3${\pm}$1.1Hz. This result showed similar aspects to the reported results of CBFs to data. We expect that this result will be applied in various clinical studies such as analysis of CBF changes by drugs or by diseaes.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.6
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• pp.496-501
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• 2005

This paper presents experimental results of the frequency offset locking of He-Ne lasers and the stability analysis. The master laser is free running, and the slave laser is a single-mode operating laser. The frequency difference of two lasers is stabilized to 200 MHz which can be synchronized using PLL servo. The measured beat frequency between two lasers was 200.004 MHz ${\pm}$ 0.15 MHz. The square root of Allan variance as a measure of stability in time domain is also measured. The long-term stability of the beat was worse than sort-term stability. With a gate time $\tau=1000\;s$, the square root of Allan variance was about 1 GHz. The results of the square root of Allan variance of the stabilized beat signal was a gate time of $\tau=1000\;s$, the square root of Allan variance was about 1.5 kHz. The long-term stability was improved by more than several hundred times compared with that without the stabilization.

• Journal of Korea Multimedia Society
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• v.20 no.8
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• pp.1395-1405
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• 2017

In this paper, we analyses heart beat data to identify subjects stress state (binary) using heart rate variability (HRV) features extracted from heart beat data of the subjects and implement supervised machine learning techniques to create the mental stress classifier. There are four steps need to be done: data acquisition, data processing (HRV analysis), features selection, and machine learning, before doing performance measurement. There are 56 features generated from the HRV Analysis module with several of them are selected (using own algorithm) after computing the Pearson Correlation Matrix (p-values). The results of the list of selected features compared with all features data are compared by its model error after training using several machine learning techniques: support vector machine, decision tree, and discriminant analysis. SVM model and decision tree model with using selected features shows close results compared to using all recording by only 1% difference. Meanwhile, the discriminant analysis differs about 5%. All the machine learning method used in this works have 90% maximum average accuracy.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.1
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• pp.1-8
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• 2018

This paper proposes a low complexity super resolution algorithm for frequency modulated continuous wave (FMCW) radar systems for foreign object debris (FOD) detection. FOD radar has a requirement to detect foreign object in small units in a large area. However, The fast Fourier transform (FFT) method, which is most widely used in FMCW radar, has a disadvantage in that it can not distinguish between adjacent targets. Super resolution algorithms have a significantly higher resolution compared with the detection algorithm based on FFT. However, in the case of the large number of samples, the computational complexity of the super resolution algorithms is drastically high and thus super resolution algorithms are difficult to apply to real time systems. In order to overcome this disadvantage of super resolution algorithm, first, the proposed algorithm coarsely obtains the frequency of the beat signal by employing FFT. Instead of using all the samples of the beat signal, the number of samples is adjusted according to the frequency of the beat signal. By doing so, the proposed algorithm significantly reduces the computational complexity of multiple signal classifier (MUSIC) algorithm. Simulation results show that the proposed method achieves accurate location even though it has considerably lower complexity than the conventional super resolution algorithms.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.113-116
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• 2001

This paper describes an analysis of the music as a time series and the fuzzy logic-based modeling of it. All music is made up of a finite number of musical notations known as the musical symbols, such as clefs, staff, tine signature, notes, rests, etc. . The musical score uses musical symbols to present various characteristics, such as rhythm, melody, chord, etc,. for interpreting the music. In this paper, it is possible to transform the beat and pitch in the musical into time series from the viewpoint of recognizing beat and pitch of sounding tone at each time. On the basis of the identified features of the musical score, a musical score is represented as a time series and then is constructed to fuzzy logic-based model for predicting them. Examples are presented to illustrate the validity of the proposed method.