• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.690-706
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• 2019

Paddy fields play an important role in the biodiversity conservation of agroecosystems as man-made wetlands. This study focused on the floristic composition and characteristics of paddy fields in South Korea. The flora surveys were conducted in 33 areas in nine provinces at two times (June and August) in 2016. The results showed that the vascular plants of the paddy fields in South Korea included 389 taxa, composed of 51 families, 219 genera, 350 species, four subspecies, 30 varieties, and five forms. Among the 51 families, Gramineae was the most diverse in species (76 taxa), followed by Compositae (61 taxa), Leguminosae (32 taxa), Cyperaceae (27 taxa), Polygonaceae (15 taxa), and Scrophulariaceae (12 taxa). Based on the occurrence frequency of each species, Digitaria ciliaris (Retz.) Koel. (100%), and Echinochloa crus-galli (L.) P.Beauv. (100%) were the highest, followed by Acalypha australis L. (97.0%), Bidens frondosa L. (97.0%), Alopecurus aequalis Sobol. (97.0%), Rorippa palustris (Leyss.) Besser (93.9%), Ludwigia prostrata Roxb. (93.9%), Lemna perpusilla Torr. (93.9%), Mazus pumilus (Burm. f.) Steenis(90.9%), Rorippa palustris(Leyss.) Besser(87.9%), Eclipta prostrata(L.) L.(87.9%), Commelina communis L.(87.9%), Artemisia princeps Pamp.(84.8%), Erigeron annuus (L.) Pers.(84.8%), Cyperus microiria Steud.(84.8%), and Aneilema keisak(Hassk.) Hand.-Mazz. (81.8%). The biological type of paddy fields in South Korea was determined to be Th-R₅-D₄-t type. Rare plants were found in six taxa: Aristolochina contorta Bunge, Penthorum chinense Pursh, Sagittaria sagittifolia subsp. leucopetala (Miq.) Hartog, Ottelia alismoides (L.) Pers., Pseudoraphis ukishiba Ohwi, and Acorus calamus L. Eighty taxa contained naturalized plants composed of 15 families, 54 genera, 76 species, three varieties, and one form. The urbanization and naturalization indices were 24.8% and 20.6%, respectively.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.447-466
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• 2019

The orchard flora where perennial fruit trees are grown may be different than in arable fields where annual crops are grown. The study focused on the floristic composition and characteristics of orchards in South Korea. The flora surveys were conducted in 36 areas in nine provinces at two times (May-June and August-September) in 2014. The results showed that the vascular orchard plants in South Korea included 466 taxa, which contained 91 families, 278 genera, 420 species, two subspecies, 39 varieties, four forms, and one hybrid. Among the 91 families, Compositae was the most diverse in species (66 taxa), followed by Gramineae (51 taxa), Leguminosae (28 taxa), Cyperaceae (18 taxa), Polygonaceae (17 taxa), Cruciferae (16 taxa), and Labiatae (14 taxa). Based on the occurrence frequency of each species, Digitaria ciliaris (Retz.) Koel. (100%) was the highest, followed by Acalypha australis L. (94.4%), Commelina communis L. (94.4%), Persicaria longiseta(Bruijn) Kitag.(91.7), Capsella bursa-pastoris(L.) L. W. Medicus(91.7%), Erigeron annuus (L.) Pers. (91.7%), Mazus pumilus (Burm. f.) Steenis (86.1%), Artemisia princeps Pamp. (86.1%), Cyperus microiria Steud. (86.1%), Stellaria aquatica (L.) Scop. (83.3%), Stellaria media(L.) Vill.(83.3%), and Echinochloa crus-galli (L.) P. Beauv.(83.3%). The biological type of orchards in South Korea was determined to be Th-₅-D₄-e type. Rare plants were found six taxa: Cinnamomum camphora (L.) J. Presl, Aristolochia contorta Bunge, Melothria japonica (Thunb.) Maxim., Ardisia crenata Sims, Gnaphalium hypoleucum DC., and Aster koraiensis Nakai. Eighty-five taxa contained naturalized plants composed of 23 families, 58 genera, 80 species, four varieties, and one form. The urbanization and naturalization indices were 26.3% and 18.2%, respectively.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.5
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• pp.402-415
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• 2001

Advantages of flash memories are their shock resistance and fast read speed, which is much faster than that of a HDD. Because of these characteristics, they are increasingly used in the traditional household electric appliance and portable handset and therefore, development of file systems which use them as storage medium is increasingly needed. But they have two problems as storage medium. First, data stored in them cannot be overwritten: it must be erased before new data can be stored. Unfortunately, this erase operation usually takes about one second. Consequently, updating data in flash memories takes long time. In this paper, their problem is solved by using a data update mechanism like LFS(Log-structured File System). Second, their erase operations are restricted. We propose novel cleaning policy in order to increase the life cycle. We implemented FAT file system, which is suitable to small storage medium and solved problems, which usually happen in implementing FAT. We evaluated the performance of sequential writes and random writes on our implemented flash file system.

• Journal of The Korean Society of Clinical Toxicology
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• v.5 no.2
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• pp.112-118
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• 2007

Purpose: There have been relatively few reports of chlorophenoxy herbicide poisoning. The purpose of this study is to analyze the general characteristics and clinical aspects of the chlorophenoxy herbicide intoxicated patients in Korea. Methods: We prospectively evaluated the chlorophenoxy herbicide intoxicated patients visiting to the 38 emergency medical centers in Korea from the 1 August 2005 to the 31 July 2006. Results: 24 patients were enrolled during the study periods. Their mean age was 55.7 years old. The median amount of the chlorophenoxy herbicide intoxicated is 150 mL. The most frequent location where the patients obtained and took the chlorophenoxy herbicide was their home. Frequent compounds involving chlorophenoxy herbicide poisoning were dicamba(66.7%), MCPP(16.7%), and 2,4-D(12.5%). The most common symptom of the patients was confusion and vomiting. 16 patients(66.7%) intended to suicide. 3 patients out of 24 patients(13.0%) were died. Conclusion: There were 24 patients intoxicated by the chlorophenoxy herbicide during the study periods. The mortality rate was 13.0%. The suicidal attempts and the numbers of death involving chlorophenoxy herbicide were high in Korea.

• Journal of Trauma and Injury
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• v.20 no.1
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• pp.40-46
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• 2007

Purpose: The primary goal of wound management is to avoid infection. Wounds in all patients presenting to the Emergency Department are contaminated with bacteria. Despite this, there is a low incidence of infection. Unfortunately, physicians continue to use antimicrobial agents indiscriminately. The authors intended to determine the effect of selective antimicrobial agents and the indications for appropriate antimicrobial agent use in traumatic simple wounds. Methods: This prospective study was performed from Jul. 2005 to Aug. 2005. A pilot study had been performed from Nov. 2003 to Jul. 2004 at the Ewha Woman's University Mokdong Hospital. Structured data sheets were completed at the times of the patient's visits to the Emergency Department and to the Outpatient Department for follow-up. Infection was determined at the time of follow-up. The indications of antimicrobial agent use are immunocompromised patients, wounds contaminated for 3 hours or longer, devitalized tissue, and extremity wounds except hand wounds caused by sharp objects. Results: The study enrolled 216 injured patients. The general characteristics of patients and wounds between the two groups were not significantly different. The antimicrobial agent use and infection rate of the pilot study were 227 cases (90.4%) and 10 cases (4.0%), and those of this study were 100 cases (46.3%) and 9 cases (4.1%). In this study, antibiotic use was reduced to almost half compared with the previous study, but the infection rate was similar (p<0.001). Conclusion: Rational use of antimicrobial agents in simple wounds reduced the use of antimicrobial agents in the Emergency Department without increasing the infection rate.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.884-888
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• 2005

An agar-degrading bacterium was isolated from north-eastern sea of Jeju island and cultured in marine agar 2216 media. Biochemical and morphologicl characteristics and 165 rRNA gene revealed that isolated strain was member of Agarivorans genus, and named Agarivorans sp. JA-1. Agarase was produced as growth-related and expressed regardless of agar presence. Optimal pH was 8 at 50 mM Clycine-NaOH buffer, and activity was maximum at $40^{\circ}C$E Enzymatic activity was maintained over $80\%$ at $60^{\circ}C$t and $70\%$ at $80^{\circ}C$ which is thermotolerant. Hence isolated novel Agarivorans sp. JA-1 strain and its beta-agarase could be used for the production of functional oligosaccharide from agar in solution state.

• 한국노년학
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• v.37 no.3
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• pp.583-600
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• 2017

The purpose of this study is to explore qualitatively what kind of coping strategy the Korean older adults use when they are depressed and why. Participants were users, older than 60, of an elderly welfare center in Seoul, and answers of 34 respondents who experienced depression were included in the analysis. The collected data were analyzed through content analysis. The results of the analysis showed that strategies to cope with depression used by participants were composed of 6 domains and 11 sub-domains: health behavior (medical approach / exercise and diet), family and social contact (social interaction / going out and going on a trip / communication with family), Religious activities (Religious activities), lifelong education (hobbies / educational activities), productive activities (labor), health risk behaviors (drinking and gambling / resignation). The depression coping strategies of the older adults and their characteristics are as follows. First, older adults used diverse problem-focused coping strategies to cope with depression. Second, older adults considered various coping strategies together and used them simultaneously. Third, the facility space for older adults functions as a shelter. Fourth, although there were cases where medical approach was used, the intention to reuse was very low. Through this study, the following suggestions were made to help older adults cope with depression more successfully. First, access to various coping strategies should be promoted. Second, more places where older adults can spend their time comfortably need to be provided. Third, resistance to mental health care should be resolved.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.439-455
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• 2018

Hanon made in the largest maar crater in Korea, is the only paddy field ecosystem in Jeju Island that has been conducting rice farming, for the past 500 years. Flora surveys were conducted eight times, 2015-2018, to understand floristic characteristics and a restoration plan of the study area. As a result, vascular plants of Hanon paddy fields were listed 225 taxa that consist of 55 families, 151 genera, 194 species, 1 subspecies, 25 varieties, and 4 forms. The taxonomic group including the most species, was Gramineae (36 taxa). The next families were Compositae (29 taxa), Cyperaceae (20), Leguminosae (13), and Polygonaceae (11). Biological type of the Hanon was $Th-R_5-D_4-t$ type. The rare plants revealed 3 taxa; Ottelia alismoides(L.) Pers., Acorus calamus L., Pseudoraphis ukishiba Ohwi. Endemic plant revealed 1 taxon; Saururus chinensis(Lour.) Baill. Forty three taxa were naturalized plants composed of 15 families, 24 genera, 41 species, and 2 varieties. The urbanization index and naturalized index were 13.3% and 16.9%, respectively. The Hanon has high plant diversity, including endemic plant and rare plants, and is the only rice paddy in Jeju Island. So, the Hanon has sufficient values in ecological and socio-cultural aspects, so it should be maintained continuously in the future.

• Korean Journal of Heritage: History & Science
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• v.50 no.2
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• pp.40-61
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• 2017

This study investigated material characteristics of composition and variable strength measurement using physicochemical and petrographic analysis for lime-soil mixture barrier tombs of Guri Galmae site in Joseon Dynasty. The tomb barriers are composed mainly of microcrystalline calcite, quartz, feldspar and mica with lime matrix. The lime matrix shows compact sheet texture, and some samples show hydration aggregates with needle-shaped textures. Gypsum occurred as a secondary process where carbonization reactions were poor. Concentrations of CaO in the tomb barrier very widely ranged from 4.43 to 36.19 wt.%, specific gravity and absorption ratio of the materials show of 1.35 to 1.62 and 20.1 to 32.6%, respectively. As the rebound hardness, the materials ranged from 10.0 to 28.4 (mean 15.7). The values are higher in the $-90^{\circ}$ direction rather than in the $0^{\circ}$ direction with the consequence that the values indicate more strength toward the vertical direction. Difference in strength by directions was caused by the directions of the tomb barriers, which is related to the processes in each stage. In the tomb barriers, ultrasonic velocity and unconfined compressive strength ranged from 1,049.2 to 1,728.9m/s and under 5.00MPa, respectively. Variation patterns between the two are very similar in values. As the result of composition and strength, the materials of higher contents on CaO are higher in strength values. Generally, techniques and skills to make the lime-soil mixture barriers are interpreted as low qualities in relatively.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.282-288
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• 2022

Facial masks have become indispensable in daily life to prevent infection and spread through respiratory droplets in the era of the corona pandemic. To understand how effective two different types of masks (i.e., KF-94 mask and dental mask) are in blocking respiratory droplets, i) we preferentially analyze wettability characteristics (e.g., contact angle and contact angle hysteresis) of filters consisting of each mask, and ii) subsequently observe the dynamic behaviors of microdroplets impacting at high velocities on the filter surfaces. Different wetting properties (i.e., hydrophobicity and hydrophilicity) are found to exhibit depending on the constituent materials and pore sizes of each filter. In addition, the pneumatic conditions for stably and uniformly dispensing microdroplets with a certain volume and impacting behaviors associated with the impacting velocity and filter type change are systematically explored. Three distinctive dynamics (i.e., no penetration, capture, and penetration) after droplet impacting are observed depending on the type of filter constituting the masks and droplet impact velocity. The present experimental results not only provide very useful information in designing of face masks for prevention of transmission of infectious respiratory diseases, but also are helpful for academic researches on droplet impacts on various porous surfaces.