• 가정과삶의질연구
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• 제8권1호
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• pp.83-100
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• 1990

The purposes of the study are to understand of rural family life cycle(FLC) and to get a FLC model for the twentieth in rural area. Data for the study were collected from 603 farm households in rural area. The major findings are as follows; 1) The age of first marriage was 21.5 years old(urban : 22.4), the first bearing 23.2(24.2), the last bearing 31.7(32.6), the first child marriage 47.2(46.5), and the last child marriage 59.7(52.7). The number of child and interval were 3.9 persons and 2.9 years respectively. From the survey results, the rural family life cycle was established. Establishment stage(from the marriage to the 1st child birth) : 21-23 yrs. Extension stage(from the 1st child birth to the last child birth) : 23-32 yrs. Complete extension stage(from the last child birth to the 1st child's marriage) : 32-47 yrs. Shrinking stage(from the 1st child's marriage to the last child's marriage) : 47-60 yrs. Complete shrinking stage(from the last child's marri ge to the death of husband) : 60-63 yrs. Dissolution stage(from the death of husband to the death of wife) : 53-75 yrs. 2) In general, the older the age, the younger the first marriage age, the greater the number of child, and the longer the interval of child bearing. The last child's marriage was too last to have the period of recovery stage. In terms of FLC by marital chorts, the later the year of marriage, the older the age of the first marriage and first baby bearing, the smaller the number of child, and the faster the launching stage. The higher the educational level, the older age of the first marriage and the first baby bering, the smaller the number of child, and the shorter the interval of child bearing. 3) Two types of rural FLC model for the twentieth were formulated. Type A was formulated based on the survey results and type B was formulated based on 『'88 population dynamics survey』 of Economic Planning Board(EPB). 「TYPE A」*Establishment stage(from the marriag to the 1st child birth) : 22.5-23.5 yrs. one child : the 1st child's marriage(49.5yrs), the death of husband(64.2yrs), the death of wife(71.7yrs) two children : the last child's birth(25.7yrs), the last child's marriage(51.7 yrs) three children : the last child's birth(27.9yrs) the last child's marriage(53.9yrs) 「TYPE B」*Establishment stage(from the marriage to the 1st child birth) : 25.3-26.3 yrs. one child : the lst child's marriage(52.3yrs), the death of husband(67.0yrs), the death of wife(74.5yrs) two children : the last child's birth(27.8yrs), the last child's marriage(53.8 yrs.) three children : the last child's birth(29.3yrs), the last child's marriage(55.3yrs).

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 추계종합학술대회
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• pp.270-273
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• 1999

Y2k 문제는 엄청난 재난을 불러 올 수도 있을 것이다. 우리는 Y2k에 의한 재난을 미연에 방지해야 하며, 그러기 위해서는 체계적인 문제 해결 방안이 모색되어야 한다. 따라서 본 연구는 선행적으로 지금까지 발생한 Y2k 문제를 분석해 보면, 시스템 부팅 불능, 타 시스템으로 정보제공에 따른 오류, 장애 발생 시각표시 오류, Calendar Day 오류, 시간관련 계산 오류, 각종 데이터 연산 처리상 오류, 세기를 두자리 “19”로 고정함으로써 세기 변경 오류, 2000년을 00년으로 인식하므로써 맨 앞으로 이동 및 저장되고 가장 먼저 삭제되며 가장 앞부분으로 정렬, 사용기간 오류, 연도범위 체크 오류, 윤년오류 문제로 나타나고 있으며, 이러한 문제를 해결하기 위해 Y2k 문제해결반을 구성하고, Y2k 문제해결반의 하부조직으로 종합총괄팀 ㆍ 기획팀 ㆍ 지원팀을 둔다. 그 조직에 의해 Y2k 문제해결을 위한 기본방침ㆍ투자지침 보완 방안 및 공급업체와 핵신 쟁점 사안에 대한 협의 및 조정의 역할을 담당하게 한다. Y2k 문제 해결을 위해 먼저 Y2k 해결 기준을 두가지 방식에 의해 Y2k해결 우선 순위, Y2k 코드 변환 원칙으로 분류하고 Y2k 문제 해결을 추진함에 있어서 자원조사ㆍ영향평가ㆍ변환설계ㆍ변환작업ㆍ현장시험ㆍ적용 등의 6단계로 Y2k 문제를 해결해야 할 것이다.

• Smart Structures and Systems
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• 제29권1호
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• pp.29-39
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• 2022

Crack detection plays an important role in the maintenance and protection of steel box girder of bridges. However, since the cracks only occupy an extremely small region of the high-resolution images captured from actual conditions, the existing methods cannot deal with this kind of image effectively. To solve this problem, this paper proposed a novel three-stage method based on deep learning technology and morphology operations. The training set and test set used in this paper are composed of 360 images (4928 × 3264 pixels) in steel girder box. The first stage of the proposed model converted high-resolution images into sub-images by using patch-based method and located the region of cracks by CBAM ResNet-50 model. The Recall reaches 0.95 on the test set. The second stage of our method uses the Attention U-Net model to get the accurate geometric edges of cracks based on results in the first stage. The IoU of the segmentation model implemented in this stage attains 0.48. In the third stage of the model, we remove the wrong-predicted isolated points in the predicted results through dilate operation and outlier elimination algorithm. The IoU of test set ascends to 0.70 after this stage. Ablation experiments are conducted to optimize the parameters and further promote the accuracy of the proposed method. The result shows that: (1) the best patch size of sub-images is 1024 × 1024. (2) the CBAM ResNet-50 and the Attention U-Net achieved the best results in the first and the second stage, respectively. (3) Pre-training the model of the first two stages can improve the IoU by 2.9%. In general, our method is of great significance for crack detection.

• 설비공학논문집
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• 제11권3호
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• pp.422-430
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• 1999

This paper concerns the study of a two-stage absorption heat pump cycle to utilize treated sewage. This two-stage cycle consists of coupling double-effect with parallel or series flow type and single effect cycle so that the first stage absorber and condenser produces hot water to evaporate refrigerant in the evaporator of the second stage. The effects of operating variables such as absorber temperature on the coefficient of performance have been studied for two-stage absorption heat pump cycle. The working fluid is lithium bromide and water solution. The efficiency of the two-stage absorption heat pump cycle has been studied and simulation results show that higher coefficient of performance could be obtained for the first stage with parallel flow type. The optimum ratio of solution distribution can be shown by considering the COP, the crystallization of solution and the generator temperature.

• 가정과삶의질연구
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• 제2권1호
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• pp.111-129
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• 1984

The purpose of this study is to make a model of Family Life Cycle in Korea now. Answers to a questionnaire were collected from 724 housewives in Seoul area, 232 housewives in big cities, 203 housewives in small cities. The questionnaire contained 10 items about family situations,. Analyzing method employed for modeling to family life cycle are frequency, percentage, X2 -test . Results and findings are as follows; 1) The mean of first marriage age is 22.4yrs old. 23.5yrs old is the result of statistical materials published by E.P.B. 1975. The age of first marriage is higher according to the age, education & residential area. 2) The mean of first baby bearing age is 24.2 yrs old (generally 1 year after marriage). This age is the same as the result of statistical materials published by E.P.B. 3) the mean of last baby berating age is 32.6 yrs old compared to the E.P.B. statistical materials 3 yrs. low. This age is very different according to the age, education & residential area. 4) The mean of first child marriage age is 46.4 yrs old compared to the E.P.B. statistical materials 2.5 yrs old low. 5) the mean of last marriage age is 52.7 yrs old. this age is also 2.3 yrs low compared to the result of E.P.B. materials. 6) The number of child & interval is quite different according to the result of family planning generation of not. 7)According to the wife's employment, it does not show and difference. 8)The result of analyzing by F.L.C.,, we don't have launching stage & middle age stage apparently. So, we can make model of F.L.C. in Korea as follows (it will be change). 1) Establishment stage; from marriage to first baby born (23yrs old -24yrs old). 2) Child bearing & rearing stage; form first baby born to first child enter primary school(24 yrs old-30 yrs old). 3) Families with children's education stage; from first child primary school to high school graduation (30 yrs old-42yrs old) 4)Families with adult children stage; form first child got army college or stay at home(42 yrs- 48 yrs old). 5)Families with children's marriage stage; from first child marriage to last child marriage (48yrs old-57yrs old). 6) Aging stage; from last child marriage to self dying.

• 대한소아치과학회지
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• 제36권3호
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• pp.325-336
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• 2009

건강한 정상 교합 어린이 83명(남자 42명, 여자 41명)을 대상으로 보호자 동의하에 cone beam CT 영상을 촬영하여, 하악 제 1대구치의 맹출 양상을 연구하였다. 대상을 발육 정도에 따라 Nolla stage(4-10단계)로 구분한 후 삼차원 기준 평면인 전두면(frontal), 시상면(sagittal), 수평면(horizontal)에서 각각 하악 제 1대구치의 맹출 양상을 관찰하였다. 1. 전두면과 수평면에서, 하악 제 1대구치간 폭경은 감소하였는데, stage 5에서 stage 8까지 가장 크게 감소했다가 약간 증가하였다. 2. 시상면과 전두면에서, 하악 제 1대구치 맹출량은 교합평면을 기준으로 stage 5에서 stage 7까지 가장 많은 맹출 이동을 보였다. 3. 수평면과 시상면에서, 하악 제 1대구치는 제 2유구치 원심면으로부터 stage 4에서 stage 6까지 원심으로 이동하였고 이후 큰 변화가 없었다. 4. 시상면에서, 교합 평면과 하악 제 1대구치의 근원심 치축이 이루는 각은 stage 4에서 stage 8까지 증가하였다. 5. 전두면에서, 교합 평면과 하악 제 1대구치의 협설측 치축이 이루는 각은 지속적으로 증가하였다. 6. 수평면에서, 정중 시상면과 하악 제 1대구치의 치축이 이루는 각은 stage 5부터 stage 8까지 증가하다 stage 8이후에는 다시 약간 감소하였다.

• 한국조사연구학회:학술대회논문집
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• 한국조사연구학회 2001년도 춘계학술대회
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• pp.59-71
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• 2001

층화 다단계 샘플링에서 모총계 추정을 위하여 동질선형추정량을 고려하고, 이 추정량의 설계기반분산추정법을 고찰하였다. 한 방법은 분산을 일단계 분산과 이단계 분산으로 구분하여 각 층에서 각각을 비편향 추정하는 방법이고, 또 다른 방법은 이단계 표본에서 선정한 부차표본을 이용하여 일단계 분산만을 추정하여 전체분산을 비편향 추정하는 방법이다. 전자는 이단계 분산이 추정 가능할 때 이용하기 좋으며 후자는 이단계 분산을 추정할 수 없을 때 용이하게 쓸 수 있다. 각각의 추정법에 대하여 동질선형추정량에 대한 비음 비편향 분산 추정량의 형태를 제안하였다. 향후 실제 조사에서 본 논문에서 제안한 분산추정법이 효과적으로 사용될 수 있기를 기대한다.

• 한국조사연구학회지:조사연구
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• 제2권1호
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• pp.59-71
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• 2001

층화 다단계 샘플링에서 모총계 추정을 위하여 동질선형추정량을 고려하고. 이 추정량의 설계기반 분산추정법을 고찰하였다. 한 방법은 분산을 일단계 분산과 이단계 분산으로 구분하여 각 층에서 각각을 비편향 추정하는 방법이고, 또 다른 방법은 이단계 표본에서 선정한 부하표본을 이용하여 일단계 분산만을 추정하여 전체분산을 비편향 추정하는 방법이다. 전자는 이단계 분산이 추정 가능할 때 이용하기 좋으며 후자는 이단계 분산을 추정할 수 없을 때 용이하게 쓸 수 있다. 각각의 추정법에 대하여 동질선형추정량에 대한 비음 비편향 분산 추정량의 형태를 제안하였다. 향 후 실제 조사에서 본 논문에서 제안한 분산추정법이 효과적으로 사용될 수 있기를 기대한다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.20-24
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• 2003

The feasibility of hybrid motor as a first stage of the air launch vehicle is investigated, and the result shows the hybrid motor can replace the solid motor. Optimal design study has been performed for the hybrid motor as a first stage of nanosat air launch vehicle. The first stage hybrid motor of the nanosat air launch vehicle, which uses the F-4E Phantom as a mother plane is designed for given mission requirements. Selected design variables are the number of ports, the initial oxidizer flux, the combustion chamber pressure, and the nozzle expansion ratio. The design results show that a hybrid motor can be successfully applicable to very small air launch vehicles which have severe physical constraints of length and diameter imposed by the mother plane.

• 대한소아치과학회지
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• 제3권1호
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• pp.7-11
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• 1976

The author measured the degree of development and the eruption pattern of first permanent molars with orthopantomography in 553 Korean children(male; 302, female; 251) from 4 to 9 years old. The orthopantomographs were obtained from dept. of pedodontics, college of dentistry, Seoul National University. The results of the studies were as follows: 1. Upper first permanent molars were erupted with distal inclination of about 30 degrees in the early stage and they gradually moved in the mesial direction by bodily movement of the tooth to be in contact with the disto-proximal surface of primary secondary molars in the late stage. 2. Lower first permanent molars were erupted with mesial inclination in the early stage and moved mesially by tipping movement of the tooth to be in contact with the disto proximal surface of the second primary molars in the late stage. 3. The eruptive forces were considered to be main etiologic factors of space closure after the premature loss of primary molars.