• 한국재난정보학회 논문집
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• 제10권3호
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• pp.466-480
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• 2014

대한민국은 사회적 고령화 문제와 더불어 재난현장 대응활동의 주역인 소방공무원 조직의 연령 구성비의 고연령화 문제 또한 심각한 상황에 이를 것으로 전망된다. 대표적인 재난대응조직인 서울소방의 경우 향후 10년~15년 사이에 50대 이상의 비율이 31%에서 40%에 이를 것으로 예상되는데, 이는 재난 현장에서 강인한 체력과 건강한 신체를 필수 요소로 하는 소방공무원에 있어서는 일반직 공무원과는 달리 심각한 문제가 되지 않을 수 없다. 본 연구는 서울 소방공무원의 연령현황과 추이를 분석하고 국내 최초로 현장활동 소방공무원의 현장활동 한계의 기준 연령을 정의하고 3가지 분석기준을 통해 개괄적이나마 현장활동 한계기준을 도출하고, 이 기준을 통해 추이분석을 하였다.

• 한국산학기술학회논문지
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• 제12권6호
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• pp.2528-2534
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• 2011

본 연구는 106개 국가 간 통계자료를 사용해 인구구조의 변화와 교육투자의 효율성 간의 관계를 검토했다. 선행연구에 기초해 전체인구 대비 청소년층 인구비율과 교육투자의 효율성과 간에는 음(-)의 관계가 존재하는 반면, 노인층 인구비율과 교육투자의 효율성 간에는 양(+)의 관계가 존재한다는 가설을 설정했다. 실증분석 결과 이상의 가설은 표본이나 모형의 선택에 상관없이 성립하는 것으로 추정됐다. 따라서 본 연구의 결과는 고령화와 저출산으로 인해 생산가능인구 감소가 심각한 사회문제로 인식되고 있는 우리나라와 같은 국가의 경우 보다 교육비지출이 효율적으로 이뤄져야 하며, 교육성과를 극대화하기 위한 제도적 장치를 마련해야 한다는 시사점을 제공한다.

• 농촌계획
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• 제25권4호
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• pp.99-107
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• 2019

This paper analyzed the characteristics of population change from 2000 to 2018 in 466 mountainous areas using resident registration data from the Ministry of the Interior and Safety, and projected the population in those areas through 2050 with the cohort change ratio method. The population had dramatically decreased from 2000 to 2009. With the slowing population decrease after 2010, the population has increased gradually since 2014. Especially the population of ages over 65 in 2018 had increased 34% compared to 2000, while the working age population had decreased 29%. This shows that population aging becomes serious problems in the mountainous area. Assuming the cohort change ratios from 2010 to 2015 and child-woman ratio in 2015 remain constant, it appeared that the projected population of the mountainous area dropped to 1.26 million in 2030 and 820,000 in 2050. It is expected to have a population with an inverted pyramid structure showing a gender imbalance with more females in 60's and 70's. Although it continues to show the recent population growth in mountainous area, population in mountainous area is expected to consistently decrease. Therefore, it is required to develop policies and strategies to promote an influx of people into mountainous area for maintaining functionality and sustainability of mountainous areas.

• 한국축산식품학회지
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• 제38권5호
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• pp.1080-1091
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• 2018

The eggshell, which is a complex and highly ordered structure, is very important factor for food safety and egg marketing. This study investigated the changes in eggshell structure and shell components in relationship to hen age. For this study, we examined the histological change of the endometrium of the 30-, 60-, and 72-wk-old commercial layers, and analyzed the ultrastructure and ionic composition of their eggshells. The results showed that histological deformation, fibrosis, atrophy and elimination of micro-villi in the uterus endometrium were found through microscopic observation that was associated with increasing hen age. Concentration of blood-ion components such as $Ca^{2+}$, $Na^+$, $K^+$, and $Cl^-$ ions did not change with age. Along with the results from the ultrastructure analysis of the eggshell, the palisade layer ratio and the density of mammillary knobs were significantly decreased in older hens. In addition, the type B mammillary knobs were frequently observed with increasing hen age. In the mineral element assay from the eggshell, $Ca^{2+}$, $S^{2-}$, and $Co^{2+}$ significantly decreased with increasing hen age, whereas $Na^+$, $K^+$, and $V^{2+}$ significantly increased. Therefore, the damages of endometrial tissue inhibit the processes of ion transmission and the crystallization of eggshell formation, resulting in a large and non-uniform mammillary knob formation. This means the conditions of endometrial cells affect the formation of the eggshell structure. In conclusion, hen aging causes the weakness of the eggshell and degrades the eggshell quality.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.132-135
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• 2004

High-performance concrete (HPC) may be expected to differ from usual concrete with respect to shrinkage behavior, and it shows high autogenous shrinkage due to the use of very low water-binder ratio (w/b) and various admixtures. Therefore, in order to minimize the shrinkage stress and to ensure the service life of concrete structure, volumetric change of HPC should be understood. In this study, small prisms made of HPC with w/b of 0.32 and blast-furnace slag content of $0\%,\;30\%,\;and\;50\%$ were prepared to measure the volumetric changes such as autogenous shrinkage, drying shrinkage, and swelling under three different curing conditions. It was observed that the concrete cured. sealed condition showed only autogenous shrinkage while the concrete let to dry condition at temperature of $20^{\circ}C$ and relative humidity of $60\%$ during the test period showed both autogenous and drying shrinkage. Moreover, the concrete exposed to dry condition after 2-day water curing swelled and then started to shrink with age. The total shrinkage (autogenous+drying) of this concrete was smaller than that of the concrete cured dry condition, especially at early-age. Therefore, the early-age moisture curing is very effective to control or minimize the volumetric change and its induced stress of HPC.

• 한국농촌건축학회논문집
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• 제19권2호
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• pp.25-33
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• 2017

This study aims to find out the change trend of the existing vacant houses in the small and medium sized farming city. And the using method of those houses is proposed in this paper. Especially to find out the change trend ratio of vacant houses in the case, the historic conservation area - Keumma village is selected as the research target area. To carry out this study, it was surveyed in 2013 when they were not designated as the special area first. And it is reviewed in 2017 when it is designated. The contents of the survey were their use, old age, structure, materials, color, roof of the main building and wall. they were surveyed by direct and interview survey. And thew were analyzed and synthesized. It is concluded that the 142 vacant houses in 2013 were declined 46houses in 2017. It is caused by the government support. And they will be declined continuously. The architectural statues of vacant houses between in 2013 and in 2017 are almost same in it's use, old age, structure, materials, color, roof of the main building and wall. In the use ratio of the vacant houses that of residence is most high, and that of warehouses, commerce are followed in turn. The reason of that statues is moving out is the first and the death of house holder, the difficulty of managing are followed. As the their re-use plan of owners, the selling is the first, constructing new buildings and the renovation them are followed. As the method of their use, re-use, community facilities, managing in the vacant houses bank are proposed. As the vacant houses are the reason of bad elements in the rural landscape in the farm village, the method of its improvement will be carried out.

• 콘크리트학회논문집
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• 제17권5호
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• pp.853-856
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• 2005

A low water/cement ratio leads to autogenous shrinkage of cement paste at an early age. This autogenous shrinkage is related to the change of relative humidity in the pore structure that is formed during the hydration process. The relationship between autogenous shrinkage and relative humidity change are relatively well defined today, but the effects of temperature on autogenous shrinkage, relative humidity, and pore structures have been studied less systematically. This study focused on correlating alterations of these properties of cement paste hydrated at constant temperatures of 20, 40, and $60^{\circ}C$. The test results clearly indicate that increasing curing temperature resulted in increased porosity, particularly for pores between 5 to 50 nm as measured by MIP, and increased autogenous shrinkages, as a consequence of a reduction of relative humidity at early ages.

• 수면정신생리
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• 제17권1호
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• pp.21-27
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• 2010

목 적: 일차성 불면증(primary insomnia)은 자율신경계에도 영향을 주는 것으로 알려져 있는데 심박동률변이도 (heart rate variability: HRV)를 이용하여 일차성 불면증에서 심박동률변이도 지수와 수면구조(sleep structure) 관련 변인 간의 연관성을 분석하여 일차성 불면증의 야간수면 동안 자율신경계 변화의 특징을 연구하고자 하였다. 방 법: 일차성 불면증 33명(평균연령: 36.2${pm}$14.2세, 남:여=15:18)을 대상으로 1일밤 야간수면다원검사(nocturnal polysomnography:NPSG)를 시행하여 HRV 지수 중 저주파수/고주파수 비(high frequency/low frequency ratio:LF/HF ratio)와 NPSG에서 산출된 수면구조 관련변인 간의 상관관계를 분석하였다. 결 과: 연령과 성별을 통제한 상태에서 LF/HF ratio와 서파수면(slow wave sleep)의 시간과 분율, 2단계수면시간 (stage 2 sleep)과 분율이 각각 음의 상관관계($r_p$=-0.37, p=0.04, $r_p$=-0.4, p=0.02; $r_p$=-0.42, p=0.02, $r_p$=-0.43, p=-0.01)를 가지는데 비해 각성지수(arousal index)와는 양의 상관관계($r_p$=0.65, p<0.001)를 보였다. 결 론: 일차성 불면증에서 수면구조 변화에 따라 자율신경계가 반응하고 있으며, 특히 비렘수면(Non-REM sleep)의 구성요소인 서파수면과 2단계수면의 감소와 각성 횟수의 증가가 교감신경 항진을 유발하여 불면증의 전형적인 수면 구조 변화가 심혈관계에 부정적 영향을 줄 수 있다는 것을 보여준다.

• 대한안전경영과학회지
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• 제10권2호
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• pp.225-235
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• 2008

It is expected that the change of industrial structure of Knowledge based economy, and service based economy would affect on economic life of physically-challenged person with no exceptions. There have been some former studies which have been misunderstood the employment of disabled due to the declining employment of the disabled and prejudice to the disabled based on biased perspective and public opinion. This study have analyzed the employment conditions of the ordinary workers and disabled workers out of those prejudices and biased opinions. Wage, economic activity ratio, age, educational background and industry those 5 parameters are brought for analyzing the two comparison group. Each parameter have compared based on the statistical data of ordinary workers and disabled workers for past 7 years. Weight between each parameter have been drawn by collecting the experts' opinion using AHP(Analytic Hierarchy Process), and utility of employment of two comparison groups have been estimated through progress inclination of each parameter. Through the estimated outcome, present condition and controversial issues and way of improvement of domestic employment of ordinary workers and the disabled is mentioned.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 추계학술대회
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• pp.405-419
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• 2008

It is expected that the change of industrial structure of Knowledge based economy, and service based economy would affect on economic life of physically-challenged person with no exceptions. There have been some former studies which have been misunderstood the employment of disabled due to the declining employment of the disabled and prejudice to the disabled based on biased perspective and public opinion. This study have analyzed the employment conditions of the ordinary workers and disabled workers out of those prejudices and biased opinions. Wage, economic activity ratio, age, educational background and industry those 5 parameters are brought for analyzing the two comparison group. Each parameter have compared based on the statistical data of ordinary workers and disabled workers for past 7 years. Weight between each parameter have been drawn by collecting the experts' opinion using AHP(Analytic Hierarchy Process), and utility of employment of two comparison groups have been estimated through progress inclination of each parameter. Through the estimated outcome, present condition and controversial issues and way of improvement of domestic employment of ordinary workers and the disabled is mentioned.