• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.129-138
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• 2002

This paper presents a study on the discharge capacity of geotextiles as a horizontal drain layer placed between the layers of earth fill and natural soft ground. Required discharge capacity of geotextiles as drain layers estimated by consolidation analysis is proportional to the consolidation coefficient of the ground soils and the width of the earth fills. The field discharge capacity of the geotextiles are measured by the hydraulic transmissivity test. And the results show wide variation according to the material characteristics of geotextiles, water content of the soils, vertical pressure, and etc. For the short horizontal drain length, geotextile filter mat can be used for the horizontal drain layer. And f3r the long drain($25{\sim}55m$), it is used for the drain together with Bord Drain.

• The Korean Journal of Ecology
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• v.23 no.4
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• pp.309-313
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• 2000

Since specific types and physical characteristics of anuran calls can represent reproductive qualities of a calling male, anuran calls have been studied in context of mate choice. We in here report call types of Rana dybowskii and their variations from two different recording sites. Calls of R. dybowskii are classified to three types based on their physical characteristics and behavioral observations; 'A-call'functions to advertise locations of a calling male and to attract potential mates. A territorial male emits 'B-call'only during male-male interaction. 'C -call'is released when a male frog was clasped by another male. The A-call from two recording sites, Miwon and Wonju, shows high variations in their call characteristics.

• Journal of Families and Better Life
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• v.13 no.3
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• pp.144-155
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• 1995

본 연구는 배우자 선택과정에서의 만남의 유형, 만남의 유형에 따른 교제량(기간, 횟수) 배우자선택진행과정(처음 만날 때, 결혼을 의식하면서 만날 때, 결혼을 결정할 때의 여과망)을 밝힘으로써 배우자 선택의 메카니즘을 밝히고자 하였다. 연구대상은 서울시에 거주하는 368명의 결혼 1년 이상 5년 미만의 기혼남녀를 대상으로 하였으며 연구결과는 다음과 같다. 만남의 유형은 의도적인 것과 우연한 만남이 비슷한 수준이었고, 23-26세에 처음 교제를 시작하여 평균 한 달에 10회 2년 이하의 교제기간을 거치며 6-12개월에 결혼하고 싶다는 생각과 함께 결혼을 결정하며 결혼에 이르는 것으로 나타났다. 한편 교제진행과정에 있어서 각각의 단계를 지속시키는 여과망을 살펴본 결과, 첫만남의 시기에는 근접성 여과망이나 매력 여과망이 중요한 요인으로 작용하는 반면, 결혼의식과 결정단계에서는 의견일치나 상호보완 등의 내면적인 기준이 중요한 여과망으로 나타났다. 그리고 이들이 Udry의 이론과 같이 6단계로 나뉘어 여과되지 않고 동시적.압축적으로 여과작용을 하는 것으로 나타났다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.483-490
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• 1997

The evalution of the cumulative distridution function of the noncentral $X^2$ distribution required in approxi-mate determination of the $X^2$ test. Many approximations to the cumulative distribution function of the noncentral $X^2$ distribution have been suggested. However, in selecting an approximations both simplicity and accuracy should be considered. In this note we compared various approximations in terms of accuracy and efficiency.

• Honam Mathematical Journal
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• v.40 no.3
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• pp.561-576
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• 2018

In this paper, we define null Cartan and pseudo null Bertrand curves in Minkowski space ${\mathbb{E}}^3_1$ according to their Bishop frames. We obtain the necessary and sufficient conditions for pseudo null curves to be Bertand B-curves in terms of their Bishop curvatures. We prove that there are no null Cartan curves in Minkowski 3-space which are Bertrand B-curves, by considering the cases when their Bertrand B-mate curves are spacelike, timelike, null Cartan and pseudo null curves. Finally, we give some examples of pseudo null Bertrand B-curve pairs.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.325-328
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• 2009

최근 자율 로봇을 지원하는 로봇의 지식 체계를 확립하기 위해 온톨로지 기술이 많이 사용되고 있다. 즉, 온톨로지를 통한 로봇의 지식 체계에 대한 데이터베이스 스키마를 설계하고 이에 따른 추론 시스템을 개발하는 연구가 활발히 진행되고 있는 시점이다. 이러한 관점에서, 본 논문은 독거 노인을 보조하는 실용적인 SilverMate 로봇분야와 같은 로봇의 지능적인 서비스를 요구하는 분야에서 로봇의 지식 체계 프레임워크를 제공하는데 초점을 두고 있다. 제안하는 지식 체계는 로봇의 자전적 기억을 중심으로 자전적 기억을 기술하기 위한 5W1H 모델을 제안하고 의미적 상관관계를 기술하기 위해 의미기억 모델로서 SCOT-SN 모델, 절차적 기억 모델로서 TES 모델을 정의한다.

• Journal of Food Hygiene and Safety
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• v.31 no.2
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• pp.132-139
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• 2016

The purpose of this study was to investigate the contents of antioxidant compounds and antioxidant activities in teas. A total of 99 teas were tested for their antioxidant activities based on their ability to scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical. Antioxidant activity was expressed as mg of ascorbic acid equivalents per 100 g tea sample (L-ascorbic acid equivalent antioxidant capacity, AEAC) and was expressed as mg per 1 serving size (free radical scavenging activity, $FSC_{50}$). The total polyphenol contents of the extracts was quantified using the Folin-Ciocalteu method and the total flavonoid contents of the extracts was determined using a modied method of Davis. Vitamin C was analyzed by HPLC method. According to the AEAC value, mate tea, green tea, black tea, oriental raisin tea, chamomile tea and burdock tea showed relatively high antioxidant activities. Polyphenolic compounds were the major naturally occurring antioxidant compounds found in teas and the high concentrations of total polyphenol compounds were observed in black tea, green tea and mate tea. The high concentrations of total flavonoid compounds were observed in mate tea, black tea and yam tea and the amount of vitamin C contents were found to be high in citron tea and green tea. As a result, steeping tea was much higher in antioxidant activity than either powdered tea or liquefied tea. According to the study, a high correlation was demonstrated between the total polyphenol contents and antioxidant activities in teas (r = 0.846) and correlations between the total flavonoid contents and antioxidant activities was statistically significant in teas (r = 0.625). It was found that also the proportional relationship established among the total polyphenol content and antioxidant activities. That is, antioxidant activity of teas has been confirmed to have been caused by the total polyphenol.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.391-400
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• 2015

In the present study, 50% ethanol extract, the ethyl acetate and aglycone fraction were prepared from mate (Ilex paraguariensis) and their antioxidative ability was evaluated. The yields of extract and fractions were 32.0, 4.48 and 0.82% per dried powder, respectively. Free radical scavenging activities were performed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and total antioxidant capacity was estimated using luminol-dependent chemiluminescence assay. Free radical scavenging activities ($FSC_{50}$) of 50 % ethanol extract, ethyl acetate fraction and aglycone fraction were 8.83, 5.84 and $6.05{\mu}g/mL$, respectively. Their total antioxidant capacities ($OSC_{50}$) were similar to that of L-ascorbic acid ($1.72{\mu}g/mL$), known as a prominent water soluble antioxidant, in all extracts and 50% ethanol extract ($1.03{\mu}g/mL$) was the most effective. The cellular protective effects on the $^1O_2$-induced cellular damage of erythrocytes were evaluated and the results showed that all extracts were significantly higher than (+)-${\alpha}$-tocopherol at $10{\mu}g/mL$. Especially, the ${\tau}_{50}$ value of aglycone fraction was 5 times higher than (+)-${\alpha}$-tocopherol at $10{\mu}g/mL$ and $50{\mu}g/mL$. The inhibitory effects of the ethyl acetate and aglycone fractions on tyrosinase were similar to arbutin, known as the whitening agent in cosmetics. These results suggest that the extracts of mate have the applicability as antioxidant and anti-aging cosmeceutical ingredients.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.1
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• pp.17-25
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• 2001

The purpose of this study is to substitute water-based painting materials for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters. This study assessed the exposure of organic solvents to the painters using water-based and solvent-based painting materials and compared compositions, painting processes and the health hazards of the application of these alternative painting mate rials. The results of this study are as follows. 1. solvent-based painting materials used in motor-repairing process consist of various organic solvents, which consist primarily of toluene, xylene, ethyl benzene, ethyl methyl benzene, trimethyl benzene, ethyl acetate, butyl acetate, methyl isobutyl ketone, 2-ethoxy ethanol, 2-ethoxy ethyl acetate and toluene-2,4-diisocianate and the others. These organic solvents are known as health-hazardous substances. But water-based painting materials are high-solid, low-solvent one sand consist of such two organic solvents as 2-butoxy ethanol and 2-heptanone and the others. 2. The painters us ing solvent-based painting mate rials in motor-repairing process are exposed to various organic solvents which consist of toluene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, trimethyl benzene, 2-ethoxy ethanol, and 2-ethoxy ethyl acetate. But the painters using solvent-based ones are only exposed to 2-butoxy ethanol and 2-heptanone. 3. By using water-based painting materials in stead of solvent-based painting materials containing health-hazardous organic solvents, the exposure of such organic solvents in the painter's breathing zone can be largely prevented. 4. This study recommends water-based painting materials as substitutes for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters.

• Journal of Families and Better Life
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• v.9 no.2
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• pp.155-170
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• 1991

The purpose of the study was to investigate the effects of demographic-socialogical variables.(ie. educational level, duration of marriage, mate selection type, monthly income, number of children and the frequencies of family's jonit-leisure-activity) and efficiency of the interspous communication on marital satisfaction over the family life cycle. The subject were 278 husbands and wives living in Seoul area who had the eldest child attending at elementary school, middle school , high school and university , respectively. The families were categorized to Duvall's family life cycle. Before the main study was conducted from SEP. 27 to OCT. 8. 1990. a pre-test was conducted on 52 subjects form SEP. 20 to SEP.23.1990. The values of Chronbach's α were obtained on the efficiency of the interspouse communication (α =0.885) and marital satisfaction (α=0.939). Data analysis was by Chronbach's α, ANOVA. Pearson's Product Moment Correlation. Path Analysis and Multiple Regression Analysis. The results were as follows; 1) Marital Satisfaction was positively related (1) to demographic-socialogical variables; educational level , monthly income, the frequencies of family's joint-leisure-activity (2) the efficiency of the interspouse communication. 2) Efficiency of the interspouse communication was positively related to the frequencies o family's joint-leisure-activity. 3) The relative importance of independent variables on marital satisfaction over the family life cycle was found to be varied in each stage of life cycle. (1) As for the group who had elementary-school-aged children; efficiency of the interspouse communication (β=0.717.p<.001), joint-leisure-activity frequency (β =0.303.p<.001), monthly income(β=0.202.p<.001), mate selection type(β=0.180.p<.05), (2) As for the group who had middle-school-aged children; efficiency of the interspouse communication (β=0.702.p<.001), (3)As for the group who had high school-aged children; efficiency of the interspouse communication (β=0.488.p<.001), joint-leisure-activity frequency (β=0.368.p<.001), (4)the group who had university-aged children; efficiency of the interspouse communication.(β=0.729.p<.001), monthly income (β=0.164.p<.01). The regression model showed that 55 percent of the marital satisfaction could be account for by demographic-socialogical variables and efficiency of the interspouse communication (R2=0.551)