• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.106-108
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• 2020

This paper introduces a new pulse-width modulation (PWM) method to reduce common-mode voltages (CMVs) and compare its performance with other reduced CMV-PWM (RCMV-PWM) methods. To avoid the use of zero-vectors which cause high CMV peaks, the introduced method splits every reference vector into two vectors such that the peak-to-peak magnitude of CMV is reduced by one-third of conventional space-vector PWM (SVPWM). The performance of RCMV-PWMs altered by the modulation index are analyzed with simulation results.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.2
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• pp.119-127
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• 2020

According to previous studies, an impaired pulmonary function is associated with arterial stiffness (AS). The pulse pressure (PP) is an important predictor of AS, but the association of an impaired pulmonary function with the PP is unclear. Therefore, this study assessed the associations between the PP and the predicted forced vital capacity (predicted FVC) and predicted forced expiratory volume in one second (predicted FEV₁) in Korean non-smoking adults. The data obtained from 6,857 adults during the 2013~2015 Korean National Health and Nutrition Examination Survey were analyzed. After adjusting for the related variables, the ORs of restrictive pulmonary disease (RPD, the predicted FVC<80.0% with FEV₁/FVC≥70.0%) using the normal PP group (PP≤60 mmHg) as a reference group was significant for the high PP group (PP>60 mmHg; 1.337 [95% confidence interval (CI), 1.049~1.703]). In addition, the ORs of obstructive pulmonary disease (OPD, FEV₁/FVC<70.0%) using the normal PP group as a reference group were significant for the high PP group (1.339 [95% CI, 1.093~1.642]). In conclusion, a high PP is positively associated with both RPD and OPD in Korean non-smoking adults.

• Journal of Welding and Joining
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• v.19 no.1
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• pp.40-48
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• 2001

An ultrasonic test method, as a nondestructive test is applied to ensure the clad interface quality assessment. According to the reference codes and standards, not only korea Industrial Standard(KS) but also American Society for Testing and Materials (ASTM) Standard, ultrasonic examination procedures use the pulse-echo, A-scan, back reflection signal drop method and/or side drilled reference hole used to establish the acceptance criteria of clad material test. But the variety of bonding materials and sizes makes it difficult to produce the reference blocks, or thus the criteria. In order to overcome these practical difficulties, new ultrasonic testing criterion is suggested. In this new method, the theoretical interface reflection signal amplitude level is calculated and suggested as an acceptance criteria with the back reflection signal set to 100% FSH(Full Screen Height) which is based on acoustic impedance mismatch at the clad interface for the explosive clad ultrasonic inspection. Applicability of suggested criterion, for the explosive clad Fe-Naval Brass with different bonding quality is confirmed to the pre-existed KS and ASTM specifications and verified by using SEM (Seanning Electron Microscope) micrograph. The results obtained by the suggested method is more conservative than the results according to the KS B 0234 and ASTM A 578 specifications The suggested method could be applicable to any other combination of explosive clad ultrasonic inspection.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1966_1967
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• 2009

As an attempt to characterize the pulse behaviors at the three pulse diagnosis positions in the oriental medicine which are called Chon, Gwan, and Cheok, we measure the pluse waveforms by SphygmoCor apparatus, that has been used widely for the evaluation of the arterial stiffness, and examine the Augmentation Index (AIx) at the aorta. For the study, twenty healthy men at the age of twenties have participated as the subject group. The pulse has been measured twice at the three palpation positions, and by two-way repeated measures ANOVA we tested the repeatability and the mean differences in the aortic AIx between Chon, Gwan, and Cheok. The AIx was found to be statistically different between the measurement positions. Duncan's test shows that the AIx is statistically different between Chon and the other two positions. Our study may be used as a reference for further scientific quantification of the pulse diagnosis.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.591-598
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• 2016

For the mobile healthcare environment, it is important to measure the exact biomedical signals in real time, and another key point is to design mobile healthcare devices with low power consumption. In this paper, we propose a method in which the piezo film sensor(PFS), having a low power characteristic, is used to measure the pulse signal synchronized with the heart rate from the radial artery. The critical issue in the bio-signal processing is the existence of the motion artifacts. To dissolve this problem, we have applied the periodic moving average filter using the quasi-periodicity of the pulse signal in addition to the conventional method of the adaptive filtering using the reference signal. Results of simulation and experiments are presented to confirm that the quasi-periodicity of the PFS signal can be used to eliminate completely the motion artifacts which still appears after the adaptive filtering.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.4
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• pp.210-220
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• 2002

We analysised the effect of harmonics on electric machines of substation power system barred on quantitatively measured harmonics and proposed the methods for prevention of harmonics through checking on transformer, rectifier and cable's capacities against harmonics with reference to KEPCO's electricity service standard. In order to analysis harmoninics of silicon rectifier that is power source in DC substation, computer simulations for a substation with TR of high voltage distribution switchboard are performed. Simulation results show that the total harmonic distortion factor becomes smaller for TR primary and receiving points in order rather than silicon rectifier which is harmonic generation source so that the harmonics generated frets each rectifier are outflowed to power supply and high voltage distribution switchboard The result of higher distortion factors of voltage and current for rectifier with 100% load than those with 50 % and 30% indicates that the waveform of voltage and current for the real substation power system at the office-going and the closing hours with heavy loads might be more distorted. As proposed methods for harmonic reduction, the conventional 6 pulse-type for substation is required to be replaced by 12 pulse-type for reduction of 5th and 7th harmonics. The active filter rather than the passive filter is more effective due to severe variance of rectifier loads, but the high cost is price to be paid. In view of installation area and costs, the use of 12 pulse-type transformer is desirable and then the parallel transformer and the rectifier within the substation must be replaced at the same time. Other substations with parallel feeder can use 6 pulse-type transformer.

• Journal of Acupuncture Research
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• v.19 no.2
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• pp.14-27
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• 2002

Objective : The aim of this study is to reveal the meaning of Shi-Dong-Bing and Suo-Sheng-Bing through investigating the origin of Shi-Dong-Bing and Suo-Sheng-Bing. Methods : We analyzed and compared the meridian symptoms of "ju Bi Shi Yi Mai Jiu Jing, "Ju Bi", "Yin Yang Shi Yi Mai Jiu Jing" and "Lin Shu Jing Mai". Results : Suo-Sheng-Bing seems to have been originated from the meridian symptoms of "Ju Bi" and Shi-Dong-Bing is different from the meridian symptoms of "Ju Bi". therefore two meridian symptoms differ in the source of formation and they seems to be different concerning recognition system for disease. Conclusion : Shi-Dong-Bing is the meridian symptoms, in case of feeling abnormal beat by pulse diagnosis, and this pulse diagnosis method is comparative pulse diagnosis method that compare all the pulse point of every meridians. Suo-Sheng-Bing seems to be the meridian symptoms describing the disease of somatic surface with making reference to meridian-circulating positions, afterward have been increased to the related internal organ's disease.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.3
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• pp.241-248
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• 2021

The present study was conducted to assess the relationship between aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio and pulse pressure in Korean adults with hypertension. Data from 1,515 adults from the sixth Korean National Health and Nutrition Examination Survey (KNHANES VI-3, 2015) were analyzed. There were several key findings in the present study. First, aspartate aminotransferase (odds ratio [OR], 1.018; 95% confidence interval [CI], 1.002 to 1.033), alanine aminotransferase (OR, 0.982; 95% CI, 0.969 to 0.996), and aspartate aminotransferase/alanine aminotransferase ratio (OR, 1.367; 95% CI, 1.027 to 1.819) were the independent factors determining high pulse pressure. Second, after adjusting for related variables [age, gender, smoking, alcohol consumption, regular exercise, total cholesterol (TC), triglycerides (TGs), high-density lipoprotein-cholesterol (HDL-C), fasting plasma glucose (FPG), body mass index (BMI), and waist circumference (WC)], the ORs of high pulse pressure with the 1st quartile as a reference were significantly higher in the 4th quartile of aspartate aminotransferase/alanine aminotransferase ratio [1.632 (95% CI, 1.113~2.393)]. The high pulse pressure was positively associated with aspartate aminotransferase and alanine aminotransferase/alanine aminotransferase ratio in Korean adults with hypertension, but was inversely associated with alanine aminotransferase.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1027-1036
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• 2018

In this paper a new generalized space vector pulse width modulation scheme is proposed based on the principle of reverse mapping to drive the switches of multilevel inverters. This projected scheme is developed based on the middle vector of the subhexagon which holds the tip of the reference vector, which plays a major role in mapping the reference vector. A new approach is offered to produce middle vector of the subhexagon which holds tip of the reference vector in the multilevel space vector plane. By using middle vector of the subhexagon, reference vector is linked towards the inner two level sub-hexagon. Then switching vectors, switching sequence and dwell times corresponding to a particular sector of a two-level inverter are determined. After that, by using the two level stage findings, the switching vectors related to exact position of the reference vector are directly generated based on principle of the reverse mapping approach and do not need to be found at n level stage. In the reverse mapping principle, the middle vector of subhexagon is added to the formerly found two level switching vectors. The proposed generalized algorithm is efficient and it can be applied to an inverter of any level. In this paper, the proposed scheme is explained for a five-level inverter and the performance is analyzed for five level and three level inverters through MATLAB. The simulation results are validated by implementing the propose scheme on a V/f controlled three-level inverter fed induction motor using dSPACE control desk.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.14-18
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• 2006

Optical interferometer is used for various optical measurement fields in optical metrology and biomedical measurements. In an optical interferometer, optical delay line has to change the optical path length of a reference arm to match with that of a sample in and it's speed was limited by reference arm movement speed. In this paper, we proposed an all-fibered RSODRapid Scanning-speed Optical Delay) without any mechanical movement, and we applied this system to optical interferometer. Experimental setup is consist of pulse laser source (center wavelength 1304nm, pulse width 30ps, repetition rate 10GHz), two phase modulators and dispersive shifted fiber. As experimental results, we obtain the maximum time delay of 11ps at 10MHz repetition rate, and it is easily tuneable the time delay by modulation frequency and modulation voltage.