• Korea journal of population studies
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• v.29 no.2
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• pp.53-88
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• 2006

The major aim of this paper is to develop a hypothetical set of age-specific fertility rates which are logically derived and reasonably accurate in the projection of future population. The first procedure is to select a generalized log-gamma distribution model, which includes Coale-McNeil nuptiality model, in order to estimate and project a set of age-specific fertility rates by birth cohort and birth order. The second is to apply the log-gamma model with an empirical adjustment to the actual data to estimate and project the future fertility rates for relatively young birth cohorts who did not complete their reproductive career. This study reconstructs or translates a set of cohort age-specific fertility rates into a set of period age-specific fertility rates which must be hypothesized in order to establish the broader framework of future population projection. For example, the fertility at age 20 in the year of 2020 is the fertility at age 20 for the cohort born in 1990, while the fertility at age 21 in the year of 2020 is the fertility at 21 for the cohort born in 1989. In turn, once a set of age-specific fertility rates for the cohorts who were born up to the year of 2010, it is possible for one to establish an hypothetical set of period age-specific fertility rates which will be needed to project the future population until the year of 2055. The difference in the hypothetical system of age-specific fertility rates between this study and the 2005 special population projection comes from the fact that the fertility estimation/projection model used in this study was skillfully exploited to reflect better actual trend of fertility decline caused by rise in marriage age and increasing proportion of those who remain single until their end of reproduction. In this regard, this paper argues that the set of age-specific fertility rates derived from this study is more logical and reasonably accurate than the set of those used for the 2005 special projection. In the population projection, however, the fundamental issue of the hypothetical setting of age-specific fertility rates in relation to the fertility estimation/projection model is about how skillfully one can handle the period effects. It is not easy for one to completely cope with the problem of period effects except for the a minor period adjustment based on recent actual data, along with the given framework of a cohort-based fertility estimation/projection model.

• The Korean Journal of Applied Statistics
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• v.25 no.1
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• pp.1-13
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• 2012

An assumption for fractional ages should be made to obtain the net premium of the whole life insurance payable at the moment of death based on the life table. Most existing studies adopt the assumption of the uniform distribution(UDD) for the fractional ages. However, as seasonal changes may frequently lead to the deaths of elderly people, it is questionable whether the assumption of the uniform distribution is the most appropriate one for the entire age intervals. In this article, based on a real mortality data set, the appropriateness of UDD assumption for the entire age intervals is examined. And then we propose a more suitable model for fractional ages. We analyze the effect of UDD assumption through the net premium and the corresponding risk when the true distribution for the fractional ages is not uniform.

• Journal of Korea Foundry Society
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• v.12 no.2
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• pp.125-130
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• 1992

1991년 현재 우리나라에는 45개의 정밀주조공장이 있는 것으로 조사되었으나, 실제 가동중인업체는 31개사 정도였다. 이들의 90년도 총 생산량은 몰드수로는 79, 980mold로 총 6,108ton을 생산하였고, 여기에 종사하는 종업원수는 1,465명이었다. 업체의 지역별 분포를 보면, 경인, 경북, 경남의 대도시 권역을 중심으로 분포하고 있고, 특히 경인지방을 중심으로 한 수도권에 전체 업체의 58%가 분포되어 있다. 기업 연령은 10년 이상의 업체가 5개사 정도이고, 전체의 74%가 5년 이하로 기업역사가 일천한 편이다. 생산규모 면에서 월산 5,000mo1d 이상의 업체는 5개사 정도 있지만, 전체의 45% 정도는 2,000mo1d이하의 소규모 공장이다. 종업원 규모는 $20{\sim}50$인인 업체가 전체의 45%로 가장 많았으며, 50인 이하가 71%를 차지하고 있다. 생산 재질별로는 주강 및 특수강 제품이 주종을 이루며, 일부 업체가 알루미늄 및 동합금을 생산하고 있다. 금번조사에서 제품의 품목별 생산에 대한 통계는 수집되지 않았으나, 주종이 valve부품, 식품, 섬유기계, 일반기계, 컴퓨터 부품 등으로 저가 제품이 주종을 이루고 있다. 정밀주조업체는 금후 정밀주조분야의 시장증대에 대한 전망을 밝게 보고 있지만, 상당수의 공장이 현재의 당면 애로사항으로서 기능인력의 부족과 함께 생산량 확보를 거론하고 있다. 또한 수입 원 ${\cdot}$ 부자재의 공동구매에는 반대의 입장을 보이고 있는 점이 특이하다.

• Food Science and Preservation
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• v.11 no.1
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• pp.12-16
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• 2004

This study was to investigate the preference test of among 10’s and 20’s in New York, Atlanta, Chicago and Sanfrancisco in USA. Preference of packaging, design, printing, flavor, texture and overall preference surveyed. About thirty percent of the respondents showed high score in packaging among the items. The design and color of Yukwa was 22.0％ and 24.1％ in “excellent”. American did not prefer the texture due to stickiness of Yukwa. However, 92.7％ of the respondents showed high score in overall acceptability of Yukwa. On the basis of this result Yukwa would he developed for residential people’s preference. It is possible to export successfully the Korean traditional snack, Yukwa.

• Korean Journal of Ichthyology
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• v.29 no.3
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• pp.176-189
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• 2017

Age estimation and sexual dimorphism of Coreoleuciscus splendidus were estimated using otolith, length-frequency distribution and 23 morphological measurements, from 245 individuals collected from September 2016, February and April 2017 in the Gapyeong stream, Han River, Korea. Result of age estimation of C. splendidus, we most examined were 2, 3 and 4-age, and the maximum observed ages were 5-age. Nine out of twenty-three morphometric measurements were significantly different between the genders. Anal fin have showing major sexual dimorphism in particular between adult individuals. This sexual dimorphism was based on extension of anal fin soft rays of male individuals. Therefore anal fin of males is always longer and wider than females. During spawning season male individuals possess nuptial tubercles on anal fin rays. However, another measurements and morphological characters does not exhibit sexual dimorphism in the between male and female individuals. The sexual dimorphism was observed to only over 2-years old individuals with sexual maturity. But juvenile and 1-years old individuals do not have sexual dimorphism with sexual maturity. Peak season of spawning was April to May and they start first spawning at 2-age. The ages at major spawning groups were most 3-age, and they maximum GSI index was 14.91 (female), 8.96 (male) at 5-age, respectively.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.78-82
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• 2015

The purpose of this study was to survey the anti-HBs positivity and titers of antibody in current students who received nationwide vaccination against Hepatitis B virus which targeted infants in 1995. The subjects were 262 students in Gyeongnam province from April 2014 to October 2014. The positive rate of anti-HBs was 55.3% (145 people) and the negative rate of anti-HBs was 44.7% (117 people). Positivity was shown to be higher in women than men. However, there was no statistically significant difference. Of the HBV-vaccinated subjects, 117 (44.7%) had anti-HBs titer <10, which is judged to be negative, 126 (47.8%) had anti-HBs titer 10-499.9 mIU/mL, which is judged to be positive, and 22 (7.3%) had anti-HBs titer more than 500 mIU/mL. The rate of anti-HBs with lower titer (10-99.9 mIU/mL) was 62% in the positive group. Classifying the antibody titer according to age, the rate of anti-HBs positivity in titer with less than 100 mIU/mL was indicated to be 78.3% in cases of 19-20 year old and 46.7% in 21-22 year old, 52.3% in 23-24 year old. A case of the lower titer with 10-99.9 mIU/mL, showed significant difference according to age. As a result of research, the antibody titers is decreased depending on the passage of time. Hence, the checking of anti-HBs titer is needed after Hepatitis B vaccination and many healthy adults will need periodic boosters of hepatitis B vaccine to maintain production of antibody to hepatitis B surface antigen.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.543-549
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• 2013

This study was conducted to evaluate age-specific and generalized allometric equations and biomass expansion factors (BEFs) for each tree component across three age-sequence stands (35-year-old, 51-year-old, 62-year-old) of black pine (Pinus thunbergii Parl.) in Jinju, located in the western part of Gyeongnam province, Korea. Biomass in each tree component, i.e. foliage, branch, and stem, was quantified by destructive tree harvesting. Allometric regression equations were significant (P<0.05) with diameter at breast height (DBH) or combination of DBH and height ($DBH^2H$) accounting for 55-98% of the variation (as indicated by coefficients of determination, $R^2$) in aboveground biomass except for foliage biomass of the 62-year-old stand. Generalized allometric equations can be used to estimate the biomass of black pine stands because the slopes of age-specific equations over 35-year-old stands were not significantly different by the age-sequence. The stem density and biomass expansion factor (BEFs) were not significantly different (P>0.05) from different stand ages and ranged from 0.45 to $0.51gcm^{-3}$, and from 1.32 to 1.38, respectively. The results indicate that allometric equations, stem density and aboveground BEFs in the matured black pine over 35-year-old are little influenced by different stand ages.

• Journal of Preventive Medicine and Public Health
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• v.22 no.2 s.26
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• pp.276-282
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• 1989

The objective of this study was to examine the impact of changes in maternal age and parity distribution on birth weight. The study population included 7,786 single live births in 1977 and 8,671 single live births in 1987 delivered at 9 medical facilities in Pusan. Data were obtained from the delivery record. The proportion of infants born to the mothers of 25-29 years increased from 56.475 in 1977 to 65.1% in 1987 and the proportion to the mothers of 30-34 years increased from 18.8% in 1977 to 21.6% in 1987. In the same period, the proportions of 1st and 2nd birth order were increased from 56.9% and 28.8% to 59.9% and 36.8%, respectively. The proportion of infants born to the age group of ${\leq}24\;and\;35{\leq}$ years were decreased in 1987. The proportion of births of the third or higher birth order was decreased from 14.2% in 1977 to 3.3% in 1987. Low birth weight (<2500gm) incidence rate was 5.3% in 1977 and it was decreased to 4.0% in 1987. It was estimated that changes in maternal age-parity distribution accounted for 10.7% of the decreased in low birth weight incidence rate. Rest of the change (89.3%) was attributed to the reduction of age-parity specific low birth weight incidence rate. Application of the direct adjustment method was considered to be an adequate tool for evaluating the impact of family planning on neonatal health.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2002-2011
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• 2015

This study was performed to determine the levels of physical function (ADL, IADL) and to reveal its association with the related factors in the elderly people. The study subjects were 1,756 (male 872, female 884) people aged over 70 who received medical check-ups and long-term care services between 2009 and 2012 from the National Health Insurance Corporation. As a result, the distribution of impaired ADL and IADL increased significantly with age. Logistic regression showed that the risk ratio of impaired ADL was increased significantly in the following groups: female, urban, low weight, stroke history group, smoking, alcohol drinking, and not regular exercise group. The risk ratio of an impaired IADL were increased significantly in the group of females, low weight, smoking, alcohol drinking. On the other hand the risk ratio of an impaired ADL and IADL was similar in each age group. As above results, the levels of ADL and IADL in the study subjects are closely related to the socio-demographic characteristics and health related behaviors. In particular, they suggested that the levels of ADL and IADL were lower in the poor group of the health-related behaviors, such as smoking, alcohol drinking, and regular exercise.

• Economic and Environmental Geology
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• v.22 no.1
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• pp.17-20
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• 1989

Two rhyolitic rocks were taken at punggog of the Jangseong sheet in the Taebaegsan mineralized area and isotopically dated by K-Ar whole rock method. One is a rhyolite which gives $62.69{\pm}1.15Ma$ and the other is a rhyolitic tuff which gives $51.67{\pm}6.64Ma$, respectively. Generally K-Ar whole rock ages of the volcanic rocks can be assumed to be the formation age of them, if there is no geological criterion of secondary effects. But the two rhyolitic rocks were slightly hydrothermally altered and the age the rhyolitic tuff is a little younger than that of the rhyolite. However, there is no geological criterion to show any big hiatus between them in field, yet. Therefore, the age data would be interpreted, as that the rhyolitic rock mass has been probably extruded at about 60 Ma, a little older than 60 Ma, in the area. The ages of them probably appear to be secondary ages after the alteration. This fact well coincides with the K-Ar whole rock age of quartz-porphyry ($57.25{\pm}0.89Ma$) distributed near the 1st Yeonhwa Pb-Zn mine (Park et al., personal comm.), because the quartz-porphyry look to be a product of hydrothermal alteration of the volcanic rock.