• Transactions on Electrical and Electronic Materials
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• v.9 no.5
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• pp.213-219
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• 2008

Pulse waves continuously change with respect to the characteristics and status of the cardiovascular system and in relation to the blood pressure (BP) and the pulse wave velocity (PWV). Monitoring the vascular condition by analyzing the variations in pulse waveforms has been used to diagnose vascular disorders and in drug treatment of arteriosclerosis and peripheral circulatory obstruction. In this paper, we investigated the vascular characteristic index with regard to the BP and classified by pulse wave signals. The pressure pulse wave and photoplethysmography (PPG) were measured simultaneously while subjects exercised, producing changes in the BP, to analyze the variation in the vascular characteristic index. We investigated the correlation between the BP and vascular characteristic index with regard to the classification methods of the pulse wave. The reflection index (RI) and vascular stiffness index were correlated with the diastolic BP, but no correlation was found between these parameters and the systolic BP. These results suggest the possibility of estimating BP through simple measurements of pulse waves.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.109-117
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• 2011

Assuming that photons absorbed by a vessel do not have acute variations, DC component reflect the basal blood volume (or diameter) before blood pulsation. Vascular stiffness and reflection is influenced by changes in basal blood volume (or diameter). This paper describes analysis of the characteristic variations of vascular stiffness, according to relative variations in DC components of the PPG signal (25-75%). For quantitative analysis, we have used parameters that were proposed previously, reflection and stiffness index, and the second derivative of PPG waveform, b/a and d/a. Significantly, the vascular stiffness and reflections were increased according to increase in DC component of the PPG signal for more than about 3% of baseline values. The systolic blood pressure were increased from $113.1{\times}13.18$ to $116.2{\times}13.319$ mmHg, about 2.76% (r = 0.991, P < 0.001) and the AC component of the PPG signal were decreased from $2.073{\times}2.287$ to $1.973{\times}2.2038$ arbitrary unit, about 5.09% (r = -0.993, P < 0.001). It is separated by DC median and correlation analysis was performed for analyzing vascular characteristics according to instantaneous DC variations. There are significant differences between two correlation coefficients in separated data.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.759-772
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• 2019

Objective: To investigate the value of ultrasound (US) microflow assessment in distinguishing malignant from benign solid breast masses as well as the association between US parameters and histologic microvessel density (MVD). Materials and Methods: Ninety-eight breast masses (57 benign and 41 malignant) were examined using Superb Microvascular Imaging (SMI) and contrast-enhanced US (CEUS) before biopsy. Two radiologists evaluated the quantitative and qualitative vascular parameters on SMI (vascular index, morphology, distribution, and penetration) and CEUS (time-intensity curve analysis and enhancement characteristics). US parameters were compared between benign and malignant masses and the diagnostic performance was compared between SMI and CEUS. Subgroup analysis was performed according to lesion size. The effect of vascular parameters on downgrading Breast Imaging Reporting and Data System (BI-RADS) category 4A masses was evaluated. The association between histologic MVD and US parameters was analyzed. Results: Malignant masses were associated with a higher vascular index (15.1 ± 7.3 vs. 5.9 ± 5.6), complex vessel morphology (82.9% vs. 42.1%), central vascularity (95.1% vs. 59.6%), penetrating vessels (80.5% vs. 31.6%) on SMI (all, p < 0.001), as well as higher peak intensity (37.1 ± 25.7 vs. 17.0 ± 15.8, p < 0.001), slope (10.6 ± 11.2 vs. 3.9 ± 4.2, p = 0.001), area (1035.7 ± 726.9 vs. 458.2 ± 410.2, p < 0.001), hyperenhancement (95.1% vs. 70.2%, p = 0.005), centripetal enhancement (70.7% vs. 45.6%, p = 0.023), penetrating vessels (65.9% vs. 22.8%, p < 0.001), and perfusion defects (31.7% vs. 3.5%, p < 0.001) on CEUS (p ≤ 0.023). The areas under the receiver operating characteristic curve (AUCs) of SMI and CEUS were 0.853 and 0.841, respectively (p = 0.803). In 19 masses measuring < 10 mm, central vascularity on SMI was associated with malignancy (100% vs. 38.5%, p = 0.018). Considering all benign SMI parameters on the BI-RADS assessment, unnecessary biopsies could be avoided in 12 category 4A masses with improved AUCs (0.500 vs. 0.605, p < 0.001). US vascular parameters associated with malignancy showed higher MVD (p ≤ 0.016). MVD was higher in malignant masses than in benign masses, and malignant masses negative for estrogen receptor or positive for Ki67 had higher MVD (p < 0.05). Conclusion: US microflow assessment using SMI and CEUS is valuable in distinguishing malignant from benign solid breast masses, and US vascular parameters are associated with histologic MVD.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1916-1917
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• 2007

Aortic AIx(augmentation index) has been used to measure aortic stiffness and evaluate ventricular load quantitatively. Algorithm for the detection of augmentation point gradually increases the differential order to detect inflection point rather than detects the distinctive point that appears after a specific time. Developed algorithm for AIx is proved to provide more accurate results than the ones developed by previous studies with the deviation from $-11.5{\pm}14.34$ points to $-3.75{\pm}1.26$ points. Results could provide the basis for the measurement of aortic stiffness using easily-measurable radial artery pulse waves, and could be extended to develop a system for early diagnosis of various vascular diseases.

• Journal of Magnetics
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• v.15 no.4
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• pp.209-212
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• 2010

Photoplethysmogram (PPG) and pressure pulse waveform (PPW) were compared and evaluated for the efficacy of stimulating knuckles by using the pulsed magnetic field. Both signals were observed simultaneously while the knuckles were exposed for 10 min to the pulsed magnetic field, with maximum field intensity of 0.8 T and transition time of 0.126 msec. After 5 min stimulation of the knuckles, the results showed that the aging indexes calculated from the second derivative of the PPG were increased from -1.913 to 0.072, and that of the PPW from -0.063 to 0.387. However, for the relatively long-term stimulation for 10 min, we found that the values of both the aging indexes of the second derivatives and augmentation index of the PPW returned to the starting level. The changes observed in characteristic factors such as the aging indexes of the second derivatives and augmentation index of the PPW indicate the potential of pulsed magnetic field stimulation as a therapeutic method for the treatment of patients with peripheral vascular disease.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.3
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• pp.11-27
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• 2016

This study is a survey of the flora distributed in Seocheon tidal flat wetland protected area of nearby island (Daejuk-do, Tokki-deung, Muk-do) and Yubo-do Seocheon-gun Chuncheongnam-do, Korea. The numbers of vascular plants were summarized as 231 taxa including 65 families, 167 genera, 204 species, 2 subspecies, 23 varieties and 2 forms. The halophytes were 33 taxa including 15 families, 29 genera, 29 species, 3 varieties and 1 form (Chenopodium album var. stenophyllum, Cnidium japonicum, Juncus haenkei and so on). The rare plants were 4 taxa including Pseudoraphis ukishiba (VU), Belamcanda chinensis (VU), Phacelurus latifolius (LC) and Polygonum bellardii (DD). The Korean endemic plants were 2 taxa including Salix pseudolasiogyne and Forsythia koreana. In the specific plants by floristic region were 24 taxa, a degree I were 19 taxa (Rhodotypos scandens, Zanthoxylum planispinum, Cynodon dactylon and so on), 2 taxa of a degree III (Elymus mollis and Asparagus oligoclonos), 3 taxa of a degree IV (Polygonum bellardii, Wisteria floribunda and Pseudoraphis ukishiba) and degree II, V were not found. The naturalized plants were 40 taxa including Phytolacca americana, Sicyos angulatus, Lactuca scariola and so on. Naturalization rate (NR) was 17.3% of all 231 taxa of vascular plants and urbanization index (UI) was 12.5% of all 321 taxa of naturalized plants. This study was performed to used as a basic data to identify the protected from plant ecosystems of type classify into analyze the vegetation characteristic of based on flora distributed in Yubu-do and nearby islands.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.3
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• pp.72-83
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• 2015

A plant diversity, which consists of indigenous plant community with Orientla thuja community (Natural monument no. 1) in Dodong, Daegu, is identified and analyzed as ecological characteristic to consider worth plants and vegetation resource of the region. The vascular plants of Thuja orientalis community were listed as 219 taxa (3.7% of all 4,881 taxa of Korean vascular plants); 67 families, 147 genera, 199 species, 16 varieties, and 4 forms. Vulnerable species (VU) and least concerned species (LC) were recorded based on IUCN standard; Koelretueria paniculata (VU), Thuja orientalis (LC), and Exochorda serratifolia (LC). Although the study site is a non-limestone area, a total of 15 taxa of calciphilous plants were identified; Cheilanthes argentea, Hypodematium glandulosopilosum, Asplenium retamuraria, Thuja orientalis, Spiraea blumei, Smilax sieboldii, etc. A total of 4 taxa endemic plants were identified; Prunus mandshurica for. barbinervis, Lespedeza maximowiczii var. tomentella, Forythia koreana (artificial origin), and Veronica pyrethrina. Among the list, 8 taxa of naturalized plants were identified; Fallopia dentatoalalta, Rumex crispus, Nasturtium officinale, Bidens frondosa, Erigeron annuus etc. Naturalization rate (NR) was 3.6%, of all 219 taxa of vascular plants and urbanization index (UI) was 2.2% of all 321 taxa of naturalized plants. Thuja orientalis occupies a lot of indigenous landscape in this study area which is the southern-limited part of a natural distribution where it can survive. The T. orientalis community, where indigenous plants have formed a characterful species composition based on habitat, has been confirmed as a worth national vegetation resource in an indigeous flora. It has been considered of plans for persistent conservation.

• Korean Journal of Oriental Medicine
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• v.16 no.1
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• pp.119-134
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• 2010

Objectives & Method：Based on the statistic from January 2008 to December 2008 include 66-year-old 375 people (159 men, 216 women) who got examined in National Health Insurance Corporation, this study set a goal to establish a new health index by analyzing the relation between the cardio-cerebra vascular disease and risk factor such as obesity, smoking, exercise, alcohol consumption, blood pressure, blood sugar and cholesterol. Results：1) Examine results, health status according to gender；People who are diagnosed as abnormal health status have higher risk for both men and women. As for the detailed diseases, high blood pressure was highest followed by hyperlipidemia and obesity. In case of the women, 96.3% in bone mineral density was highest. 2) Correlation of disease and health risk factors based on gender；Correlation of disease according to gender in the obesity(p<0.001), lipid abnormalities(p<0.001), kidney diseases(p<0.001), chest diseases(p<0.05), osteoporosis(p<0.001) showed a statistically significant difference. The analysis showed that the men have more obesity and lipid abnormalities as well as thoracic disease than the women, but the women have more kidney disease than the men. As for the osteoporosis examine which is conducted only for the women, most of the women were abnormal even though it cannot compare the result according to gender. Obesity(p<0.001), alcohol(p<0.001), smoking(p<0.001) and LDLcholesterol(p<0.001) showed statistical correlation between gender and health risk factor. And only high blood pressure(p<0.001) showed a statistical correlation between gender and risk of cardio-cerebra vascular disease. 3) Risk of cardio-cerebra vascular disease related to health risk factor characteristic；Obesity assessment(p<0.001), alcohol(p<0.05), smoking(p<0.05), blood pressure(p<0.001), glucose(p<0.001) showed correlation between health risk factor and stroke. Drinking(p<0.001), smoking(p<0.05), exercise(p<0.001), blood pressure(p<0.001), LDL cholesterol(p<0.001) showed health risk factor and myocardial infarction. Obesity assessment(p<0.001), smoking(p<0.05), blood pressure(p<0.001), glucose(p<0.001) and showed correlation between health risk factor and diabetes. Obesity assessment(p<0.001), blood pressure(p<0.001) showed correlation between health risk factor and high blood pressure. Conclusion：Therefore, we have to take one step farther after the health examination. In order to prevent and reduce the risk of disease, people have to understand their health status exactly first, and correct their habit with recognizing the amount of risk related to cardio-cerebra vascular disease.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.304-309
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• 2015

Applicable range of Photoplethysmography (PPG) becomes wider as a non-invasive physiological measurement technique. However, PPG waveform is easy to be distorted by ambient light or vascular variation from temperature changes. Especially, irregular variation of PPG waveform caused by ambient temperature not only severely distorts the PPG, but also leads miss interpretation in clinical applications. Therefore, the investigation of between temperature and PPG waveform is quite important in using PPG. The purpose of this research is to quantify the PPG waveform characteristic and to investigate the waveform variation following the temperature change on measuring site. To quantify the fluctuation of PPG waveform, we use two techniques; detrended fluctuation analysis (DFA) and AC/DC analysis of PPG. We record PPG under temperature stress, which applied by medical use heat pack ($40^{\circ}C$) and ice pack ($0^{\circ}C$). Ten participants were applied to the experiment, and the result was evaluated to approve the temperature effect with statistical method, Wilcoxon signed rank test. The result shows that the AC component (p<0.05) and perfusion index DFS scale exponent (p<0.01) of PPG have the significance to temperature stress except for a DC component of PPG.

• Korean Journal of Plant Resources
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• v.35 no.1
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• pp.71-99
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• 2022

This study was conducted to investigate the vascular flora of Masan, located in Goseong-gun, Gangwon-do, and to comprehend the distribution of remarkable plants such as rare and Korea endemic plants and invasive alien plants. The survey was carried out the distribution of vascular plants 11 times per season from 2010 to 2018. A total of 619 taxa in 93 families, 328 genera, 529 species, 6 subspecies, 78 varieties and 6 forms were identified on mt. Masan. Among them, Korean endemic plants are 21 taxa including Saussurea diamantica Nakai and are plants designated by the Korea Forest Service are 20 taxa counting Saxifraga octopetala Nakai. Invasive alien plants were classified a total of 35 taxa inclusive of Trifolium pratense L. (WS), Aster pilosus Willd. (SS), Coreopsis lanceolata L. (SR), Rumex obtusifolius L. (SC) and Lindernia dubia (L.) Pennell (CS). The naturalization rate was 5% and the urbanization index was 10.0%, respectively. Although this study identified the diverse distribution of major plants such as rare and endemic plants around Masan, it was confirmed that invasive alien plants, which pose a great threat to forest biodiversity conservation and promotion, spread and distributed in a specific section Therefore, it is urgent to establish a conservation strategy and countermeasures.