• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.71-80
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• 2019

We have been experimenting for industrialize four kinds of wildflowers(Smilax china, Saururus chinensis, Houttuynia cordata and Zizania caduciflora) which are used for Korean medicinal plants for a long time as Korean resources plants. Smilax china, Saururus chinensis, Houttuynia cordata was used for roots and Zizania caduciflora used for leaves. Extraction was carried out in 50% ethyl alcohol, which was concentrated by freezing the material and then injected at a low concentration of 100ppm. The results of the study on the antibacterial potential activity and antifungal potential activity using the four wildflowers strains were as follows. 1. The results of the sterilization and antibacterial potential activity and antifungal potential activity were as follows. Houttuynia cordata showed good inhibitory effect for Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa. The inhibitory power of Zizania caduciflora was proved to some extent. However, other cultivars showed little antibacterial and antifungal activity. 2. The antifungal potential activity against Candida albicans, Aspergillus niger, Aspergillus fumigatus, and Cryptococcus neoformans was small but some inhibition against Candida albicans was confirmed. There was no inhibition of other fungi potential at all.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.817-826
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• 2023

In this paper, a fault determination methodology based on an artificial neural network was proposed to protect the system from faults on the lines in the smart grid distribution system. In the proposed methodology, first, it was designed to determine whether there is a low impedance line fault (LIF) based on the magnitude of the current RMS value, and if it is determined to be a normal current, it was designed to determine whether a high impedance ground fault (HIF) is present using Normal/HIF classifier based on artificial neural network. Among repetitive DSP module-based algorithm verification tests, the normal/HIF classifier recognized the current waveform as normal and did not show reclosing operation for the cases of normal state current waveform simulation test where the RMS value was smaller than the minimum operating current value. On the other hand, for the cases of LIF where RMS value is greater than the minimum operating current value, the validity of the proposed methodology could be confirmed by immediately recognizing it as a fault state and showing reclosing operation according to the prescribed procedure.

• Journal of Drive and Control
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• v.21 no.2
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• pp.23-29
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• 2024

Potatoes are one of the world's four major crops, and domestic consumption is currently increasing in Korea. However, the mechanization rate of potatoes is very low, and especially, harvesting is the most labor-intensive task in potato production. In Korea, potato-collecting work depends on manpower, so it is necessary to develop a gathering-type harvester that can be used for processes from digging to harvesting. Therefore, in this study, a self-propelled-type potato harvester was developed, and its performance was analyzed to mechanize harvesting. The potato harvester was developed to have a crawler-type driving part with a 60 hp diesel engine and consisted of a digging part that digs potatoes from the ground, a vertical transporting part that transfers the dug potatoes to the height of the collection bag, a separating part that separates debris, such as stones and soil, and a collecting part that loads the collection box. A field test of the potato harvester was conducted, and performance was evaluated by the damage, loss, and debris mixing proportions, which were 2.5%, 2.8%, and 2.6%, respectively. The working capacity was 1.2 h/10 a. The economic analysis results showed that the cost of harvesting work could be reduced by 12.7% compared to manual harvesting.

• Sleep Medicine and Psychophysiology
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• v.19 no.2
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• pp.68-76
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• 2012

Objectives: Sleep disorders cause changes of autonomic nervous system (ANS) which affect cardiovascular system. Primary insomnia (PI) makes acceleration of sympathetic nervous system (SNS) tone by sleep deficiency and arousal. Obstructive sleep apnea syndrome (OSAS) sets off SNS by frequent arousals and hypoxemias during sleep. We aimed to compare the changes of heart rate variability (HRV) indices induced by insomnia or sleep apnea to analyze for ANS how much to be affected by PI or OSAS. Methods: Total 315 subjects carried out nocturnal polysomnography (NPSG) were categorized into 4 groups - PI, mild, moderate and severe OSAS. Severity of OSAS was determined by apnea-hypopnea index (AHI). Then we selected 110 subjects considering age, sex and valance of each group's size [Group 1 : PI (mean age=$41.50{\pm}13.16$ yrs, AHI <5, n=20), Group 2 : mild OSAS (mean age=$43.67{\pm}12.11$ yrs, AHI 5-15, n=30), Group 3 : moderate OSAS (mean age $44.93{\pm}12.38$ yrs, AHI 16-30, n=30), Group 4 : severe OSAS (mean age=$45.87{\pm}12.44$ yrs, AHI >30, n=30)]. Comparison of HRV indices among the four groups was performed with ANCOVA (adjusted for age and body mass index) and Sidak post-hoc test. Results: We found statistically significant differences in HRV indices between severe OSAS group and the other groups (PI, mild OSAS and moderate OSAS). And there were no significant differences in HRV indices among PI, mild and moderate OSAS group. In HRV indices of PI and severe OSAS group showing the most prominent difference in the group comparisons, average RR interval were $991.1{\pm}27.1$ and $875.8{\pm}22.0$ ms (p=0.016), standard deviation of NN interval (SDNN) was $85.4{\pm}6.6$ and $112.8{\pm}5.4$ ms (p=0.022), SDNN index was $57.5{\pm}5.2$ and $87.6{\pm}4.2$ (p<0.001), total power was $11,893.5{\pm}1,359.9$ and $18,097.0{\pm}1,107.2ms^2$(p=0.008), very low frequency (VLF) was $7,534.8{\pm}1,120.1$ and $11,883.8{\pm}912.0ms^2$ (p=0.035), low frequency (LF) was $2,724.2{\pm}327.8$ and $4,351.6{\pm}266.9ms^2$(p=0.003). Conclusions: VLF and LF which were correlated with SNS tone showed more increased differences between severe OSAS group and PI group than other group comparisons. We could suggest that severe OSAS group was more influential to increased SNS activity than PI group.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.8
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• pp.22-26
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• 2012

This paper introduces a 2.5-Gb/s optical receiver implemented in a standard 1P4M 0.18um CMOS technology for the applications of active optical HDMI cables. The optical receiver consists of a differential transimpedance amplifier(TIA), a five-stage differential limiting amplifier(LA), and an output buffer. The TIA exploits the inverter input configuration with a resistive feedback for low noise and power consumption. It is cascaded by an additional differential amplifier and a DC-balanced buffer to facilitate the following LA design. The LA consists of five gain cells, an output buffer, and an offset cancellation circuit. The proposed optical receiver demonstrates $91dB{\Omega}$ transimpedance gain, 1.55 GHz bandwidth even with the large photodiode capacitance of 320 fF, 16 pA/sqrt(Hz) average noise current spectral density within the bandwidth (corresponding to the optical sensitivity of -21.6 dBm for $10^{-12}$ BER), and 40 mW power dissipation from a single 1.8-V supply. Test chips occupy the area of $1.35{\times}2.46mm^2$ including pads. The optically measured eye-diagrams confirms wide and clear eye-openings for 2.5-Gb/s operations.

• Journal of Korean Medicine Rehabilitation
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• v.26 no.4
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• pp.85-96
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• 2016

Objectives The purpose of this study was to investigate the relationship between the effects of acupuncture treatment and heart rate variability (HRV) in pre-menopausal obese women. Methods Thirty-seven obese women who met the inclusion criteria were recruited. To estimate the effects of acupuncture, obesity indices, such as body weight (BW), waist circumference (WC), hip circumference (HC), and the waist-hip ratio (WHR), were measured before and after the treatment. The HRV test was conducted before treatment and analyzed using the frequency domain method. Results The lnLF/HF ratio (natural logarithm of low frequency power/high frequency power ratio of the HRV value) before treatments was negatively correlated with differences in WC, HC, and WHR during treatment. The correlation coefficients between the lnLF/HF ratio and the differences in WC, HC, and WHR were r=-0.459 (p<0.01), r=-0.327 (p<0.05), and r=-0.339 (p<0.05) respectively. Conclusions As the baseline ratio of sympathetic activity to parasympathetic activity decreases, WC, HC, and WHR reduction significantly increased during treatment. Further study is needed to uncover the relationship between obesity-related variables and the autonomic nervous system to predict the effect of acupuncture.

• Korean Journal of Adult Nursing
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• v.12 no.4
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• pp.741-757
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• 2000

This study was undertaken to develop an instrument to be used for measuring the concept of quality of life of Korean patients with cancer multidimensionary and correctly. It can contribute in holistic nursing care for Korean cancer patients and also provide and validate basic data to help oncology nurses measure the outcome of nursing intervention correctly. To develop this instrument, the researchers first estabilished a conceptual framework based on the results of qualitative data analysis and indepth interview method Development of the scale was conducted using a method in which 31 items were assessed by subjects' self report using linear analogue scales. The subjects were 79 D.M. patients, 103 patients with acute illness, and 91 cancer patients residing in Busan, Korea. Data were collected during the period from July, 24 to August 14, 2000. This instrument consisted of 31 items with a self report scale. This instrument covered 4 dimensions of cancer patients : 1) physical wellbeing 2) psychological wellbeing 3) social wellbeing and 4)spiritual wellbeing. Each item had a possible score of 10. The reliability of the scale was tested with Cronbach's alpha. Validity was evaluated by examining the relationships of this scale, Youn's Quality of Life Questionnare scores and the Simple Quality of Life scale. Two separate runs of multiple regression were used to predict scores on the Simple Quality of Life measurement. Further validation was obtained by examining the correlation between the instrument subscores and Youn's Quality of Life measurement subscore for convergence of this scale. Examination of the discriminant. power of the instrument was done using ANOVA test. The results are summarized as follows: 1. The reliability of the instrument for the quality of life was 0.8321(Cronbach's alpha.), physical wellbeing dimension 0.6343, psychological wellbeing dimension 0.6501, spiritual wellbeing dimension 0.5883. 2. This instrument had a high correlation with Youn's Quality of Life measurement(r= 0.636) in cancer patients, whereas it had a low correlation with Simple Quality of Life measurement(r=0.455) in cancer patients. In the D.M. patients, the instrument correlated with both the Youn's Quality of Life measurement and Simple Quality of life measurement(r=0.313, r= 0.407) and in the acute stage patients, the instrument had no correlation. 3. Multiple regression of individual items on the Simple Quality of Life scores accounted for 56.8% of the variance in the Simple Quality of Life measurement, whereas, Youn's Quality of Life measurement scores accounts for 31.7%. 4. The correlations collected from the three group had the same patterns of variations but especially the instrument developed in this study had higher disciminant power than that of Youn's Quality of Life Measurement.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.836-847
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• 2016

Water soluble oil was obtained by pyrolysis of biomass. The characteristics of emulsified fuel by mixing water soluble oil and MDO(marine diesel oil) and engine emissions were studied with engine dynamometer. Saw dust was used as biomass. Water soluble oil was obtained by condensing of water and carbon content with pyrolysis of saw dust at $500^{\circ}C$. Emulsion fuel was obtained by emulsifying MDO and water soluble oil by the water soluble oil mixing ratio of 10 to 20% of MDO. Exhaust gas detection was performed with engine dynamometer. While combustion, micro-explosion took place in the combustion chamber by water in the emulsion fuel, emulsion fuel scattered to micro particles and it caused to smoke reduction. The heat produced from water vapour reduce the temperature of internal combustion chamber and it caused to inhibition of NOx production. It can be verified by the lower exhaust temperature of each ND-13 mode using emulsion fuel than that of MDO fuel. The NOx and smoke concentration were reduced by increasing water soluble oil content in the emulsion fuel. The power also decreased according to the increment of water soluble oil content of emulsion fuel because emulsion fuel has low calorific value due to high water content than MDO. As a result of ND-13 mode test with 20% bio oil content, it was achieved 25% reduction in NOx production, 60% reduction in smoke density, and 15% reduction in power loss.

• The Journal of Internal Korean Medicine
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• v.41 no.3
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• pp.467-477
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• 2020

Objectives: This study investigated the cutaneous electrogastrogram (EGG) and other clinical characteristics of dyspeptic patients who have been diagnosed with Stomach Qi Deficiency (SQD) using the Scale for Stomach Qi Deficiency (SSQD). Methods: This study reviewed the clinical records of 38 patients with dyspepsia who were evaluated with SSQD and EGG at the Department of Digestive Diseases of Kyung Hee University Korean Medicine Hospital in Seoul, Korea from November 1, 2019 to February 29, 2020. We evaluated the EGG and other clinical characteristics of the SQD patients to determine if there was an association between the SSQD scores and the EGG. Results: In terms of the EGG, the SQD patients showed no significant increase in the percentage of normal slow wave after a meal and a slightly decreased power ratio at Channel 1 and Channel 2. We also found an association between the SSQD scores and the EGG parameters at Channel 1 and Channel 3. The average Ryodoraku score of the patients was 33.00±14.90 (μA). In the Heart Rate Variability (HRV) test, the average Total Power (TP) and Low Frequency/High Frequency (LF/HF)) ratio was 1356.60±13 6.41(ms²) and 1.68±2.25, respectively. Conclusions: The results of this study suggest that clinicians can use Electrogastrography to enhance accuracy when diagnosing the SQD pattern.

• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.278-286
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• 2022

In this study, a 33-mode Free-Flooded Ring (FFR) transducer was designed to apply piezoelectric single crystal PIN-PMN-PT, which has high piezoelectric constants and electromechanical coupling coefficient. To ensure low-frequency high transmitting sensitivity characteristics with a small size of FFR transducer, the commercial FFR transducer based on piezoelectric ceramics was compared. To develop the FFR transducer with broadband characteristics, a piezoelectric segmented ring structure inserted with inactive elements was applied. The oil-filled structure was applied to minimize the change of acoustic characteristics of the ring transducer. It was verified that the transmitting voltage response, underwater impedance, and beam pattern matched the finite element numerical simulation results well through an acoustic test. The difference in the transmitting voltage response between the measured and the simulated results is about 1.3 dB in cavity mode and about 0.3 dB in radial mode. The fabricated FFR transducer had a higher transmitting voltage response compared to the commercial transducer, but the diameter was reduced by about 17 %. From this study, it was confirmed that the feasibility of a single crystal-applied FFR transducer with compact size and high-power characteristics. The effectiveness of the performance prediction by simulation was also confirmed.