• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.62-70
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• 2007

Most design temperature of environmental test in korea is based on the standard of Department of Defense. There are few studies to establish temperature standard. Besides the representative environmental test guide 'MIL-STD-810F' encourage to tailor to generate the most relevant test data possible and to test to make a match of test environment with operational environment. Under these circumstances, it is irrational to comply with baseless daily cycle. Thus the study about design method of test temperature is essential. So, the daily cycles to be appropriate to the Korean peninsula was presented in this study. And this research shows how to derive two main element, frequency-of-occurrence and daily maximum (minimum) temperature in daily cycles, in case we can not find the daily cycle.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.371-373
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• 2001

In this paper, we present 2-step load cycle for daily load curve of up to and including 100kVA distribution transformer in domestic. Daily load patterns are classified by two methods dependent upon possession information. In case we possess daily load profiles make use of K-mean algorithm and in case we have not daily load profiles, make use of customer information of KEPCO. As the parameters of the load pattern classification, we use are daily load profiles and customer information of each distribution transformers. Data management system is used for NT oracle. We can present peak load magnitude, initial load magnitude and peak load duration for daily load patterns by 2-step load cycle for daily load curve of up to and including 100kVA distribution transformer in domestic. We think that this paper contributes to enhancing the distribution transformer overload criterion.

• Journal of Hydrogen and New Energy
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• v.22 no.5
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• pp.663-670
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• 2011

Under a daily photoperiod of 14h light and 10h dark synchronization of cell cycle in Korean Cyanothece spp. strains and $Synechococcus$ sp. strain Miami BG043511 was analyzed as to be applicable to enhanced hydrogen production. For all strains peaks of double cell were observed during the light period of a daily cycle. Peaks of maximal cell size measured by a coulter counter appeared at the peak of double cells observed under light microscope reconfirming the synchronization of daily cell cycle. The cell cycle synchronization became weakened within two days when treated with continuous illumination. Rapid detection of the peak time of double cell percentage by coulter counters may contribute to quasi-realtime feedback control for efficient production of photobiological hydrogen by unicellular cyanobacterial strains.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.7 no.1
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• pp.52-60
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• 1996

Premenstrual symptoms can begin at anytime after menache and usually remit with menopause. Numerous studies of the premenstrual symptoms have been reported, based on mature woman and clinic patients. As yet, however, no prospective study has specially examined the extent or nature of PMS in adolescents. The authors investigated the pattern of mood, behavior and physical symptom changes in the menstrual cycle for 230 high school students who reported premenstrual symptoms by using Baily Rating form(DRF), The scores on 21 symptoms of DRF were recorded daily for at least one menstrual cycle. The results as follows : 1) 1.7%(4/230) of the subjects who reported premenstrual symptoms met criteria for premenstrual dysphoric disorder(PMDD) by 30% change criteria. 2) The pattern of symptom changes in the menstrual cycle showed a clear increase in mean daily symptom score at premenstrual -1,-2 day. and reaching a maximum scores at the first day, rapidly decreased at day 4 during menstruation. 3) The mean daily symptom score in the menstrual phase was significantly higher than those in the premenstrual and postmenstrual phase, and significantly higher in the premenstrual phase than that in postmenstrual phase. 4) The scores of the subjects with longer duration of menstrual bleeding were higher than those of the subjects with the shorter duration. Particularly in the menstrual phase, there was a significant difference on the mean scores of physical symptom duster between the longer and shorter group. These results demonstrated that the mean daily pattern of symptom changes in the menstrual cycle for the subjects was similar pattern of change for the PMDD group, except high level of symptom scores if premenstrual phase. The adolescents might experienced more physical discomfort than the other symptoms in the menstrual phase Especially the subject with longer duration of mense flow were more likely to report more discomfort than that of shorter duration.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.447-450
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• 2003

It is important to calculate runoff, percolation and evapotranspiration in process hydrological cycle. Especially, a evaportranspiration in watershed has a very important effect on hydrological cycle. In the study, the watershed evapotranspiration was calculated by the water balance and a daily evaportanspiration coefficient(CE) was calculated by the modified Beken's formula.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.317-318
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• 2000

오늘날 우리는 문명이 발달하고 고도로 산업화된 사회의 구성원으로써 살아나가고 있다. 그러나 우리의 삶을 영위하는 과정에서 생긴 각종 환경오염에 노출되고 있어서 이로 인하여 우리의 삶의 질이 저하되기도 한다. 여러 가지 오염물질이 대기중에 가득한 가운데서 순간순간 숨을 쉬며 살아가는 우리 인간은 호흡기나 피부를 통하여 각종 대기오염물질에 직·간접적으로 노출되고 있는 실정이다. 이중 특히, 벤젠이나 톨루엔과 같은 휘발성유기화합물(Volatile Organic Compounds : VOCs)은 실내 생활이나 작업, 야외활동, 또 여러 삶의 과정에서도 노출되고 있는 듯 하다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.283-284
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• 2000

석유화학, 비철금속공단, 조선 및 기계공단 등과 같은 대형 산업단지를 가진 울산지역의 대기오염은 타 지역에 비하여 꽤 높은 것으로 보고되고 있다. 또한 울산지역은 인구가 백만이 넘는 대형도시이고, 사람과 각종 공단 생산제품을 수송하기 위한 교통밀도도 꽤 높으므로 많은 양의 휘발성 유기화합물(Volatile Organic Compounds : VOCs)이 배출되고 있다. 흔히 VOC는 대류권 오존 농도의 전구체로서 역할을 하여 대류권 오존농도 감소를 위한 연구가 활발히 진행되고 있다. (중략)

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.103-113
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• 2012

The ButterStar Observatory at the Dongducheon High School has been working for photographic observations of the Sun since October 16, 2002. In this study, we observed the Sun at the ButterStar observatory for 3,364 days from October 16, 2002 to December 31, 2011, and analyzed the photographic sunspot data obtained in 1,965 days. The correction factor $K_b$ for the entire observing period is 0.9519, which is calculated using the linear least square method to the relationship between the daily sunspot number, $R_B$, and the daily international relative sunspot number, $R_i$. The yearly correction factor calculated for each year varies slightly from year to year and shows a trend to change along the solar cycle. The correction factor is larger during the solar maxima and smaller during the solar minima in general. This implies that the discrepancy between a relative sunspot number, R, and the daily international relative sunspot number, $R_i$, can be reduced by using a yearly correction factor. From 2002 to 2008 in solar cycle 23, 35.4% and 64.6% of sunspot groups and 35.1% and 64.9% of isolated sunspots in average occurred in the northern hemisphere and in the southern hemisphere, respectively, and from 2008 to 2011 in solar cycle 24, 61.3% and 38.7% of sunspot groups and 65.0% and 35.0% of isolated sunspots were observed, respectively. This result shows that the occurrence frequency for each type of sunspot group changes along the solar cycle development, which can be interpreted as the emerging and decaying process of sunspot groups is different depending on the phase of solar cycle. Therefore, it is considered that a following study would contribute to the efforts to understand the dependence of the dynamo mechanism on the phase of solar cycle.

• Journal of Korean Academy of Nursing
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• v.50 no.1
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• pp.147-157
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• 2020

Purpose: This descriptive study aimed to identify the menstrual cycle characteristics and premenstrual syndrome (PMS) prevalence in Korean young adult women using the retrospective and prospective Daily Record of Severity of Problems (DRSP). Methods: In the first stage, participants included 151 nursing students studying in a university located in Seoul. Data were collected from April 20 to June 2, 2017, using the questionnaire on menstrual characteristics, pictorial blood assessment chart, and retrospective DRSP. In the second stage, participants included 17 students with PMS, based on the screening conducted in the first stage. Data were collected using the prospective DRSP from May 29 to 2 September 2, 2017. Results: Of the study sample, 104 participants (68.9%) had regular periods. Those with regular periods had 11.97 periods annually with a menstrual cycle of 29.38 days and a period duration of 5.72 days. Fifty-five participants (37.4%) showed menorrhagia. Sixty-four participants (42.4%) were found to have PMS based on their retrospective DRSP. When the ratio of women (52.9%) with PMS shown in the prospective DRSP was used as a positive predictive value, the estimated PMS prevalence was 22.4%. Conclusion: This study provides clinically significant PMS prevalence among Korean young adult women, positive predictive value of the retrospective DRSP, and valid data to basically understand the menstrual cycle characteristics experienced by these women.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.447-451
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• 2019

This study were to investigate the scratches and replacement cycles of eyeglasses according to personal characteristics in daily life. The subjects were 58 people who voluntarily participated in this study. The replacement cycle of eyeglasses according to the contact of eyelashes with eyeglasses, type and the number of eyeglasses wiped on a day were analyzed. The statistical analysis were performed by X² test and Fisher's exact test. The average replacement cycle of the eyeglasses were longer females than males. The eyeglasses replacement cycle were significantly shorter when the eyelashes contacted the eyeglasses and when the eyeglasses were wiped using a tissue or clothes other than the eyeglasses towel. The coating film of the eyeglasses may be damaged by the convergence effect such as eyelashes or minor carelessness in daily life, and this study will continue to follow up on this result.