• 아동학회지
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• 제36권4호
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• pp.209-227
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• 2015

The present study investigated maternal parenting stress trajectories, using data gathered from the Korean Children Panel Survey. Four factors-monthly income, maternal depression levels, infants' negative emotionality, marital conflict-which were taken from reports made by the mothers' used in this study, were examined as predictors of maternal parenting stress trajectories. The effects of maternal parenting stress trajectories, parenting styles and toddlers' peer interruptive behaviors were also examined. The findings were as follows: First, maternal parenting stress trajectories somewhat increased from the 1st year period to the 4th year period. Second, infants' negative emotionality and marital conflict within the first year were observed to have a connection to the initial level and slope of maternal parenting stress trajectories. Third, maternal parenting stress trajectories predicted positive parenting styles, and parenting styles had a longitudinal impact on toddlers' peer interruptive behaviors at the 5th year period.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제16권2호
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• pp.47-54
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• 2010

This paper is a longitudinal study, comparing survey results between two time periods. A previous survey was conducted in 1999. After 10 years of the first survey, the second survey was conducted while utilizing the same questionnaire. A list of membership of Korea Institute of Heallthcare Architecture was used as a sampling frame. At the first survey in 1999, questionnaires of 27.3 percentage were returned, and 15.5 percentage in the 2008 survey. Healthcare design is one of the highly specialized design types in architecture. In addition, it is demanded highly specialized knowledge to solve healthcare design problems. As a professional service firm(PSF), architectural firm utilizes knowledge assets to provide design service to clients. Specialized knowledge in question is one of the core assets of PSF. The knowledge generates competitive advantages and plays an effective role as a marketing tool for PSF. However, empirical studies dealing with the knowledge characteristics of specialized design(healthcare) firms were hardly found. Thus, this study aims to trace the professional architects' perception of knowledge demands for task performance and architectural knowledge assets. The results can be used as a reference when a specialized firm in healthcare design initiates to build knowledge assets in it.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.916-919
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• 2000

A great deal of research has been done in the field of characterization for piezoelectric thin films after the first report on the measurement for the piezoelectric coefficient of thin films in 1990. The main idea of this research is to provide a distinctive solution for the measurement of both the longitudinal and the transverse piezoelectric d-coefficients, d$\sub$33/ and d$\sub$3l/, of ferroelectric thin films and also thick films. In general, to get these two coefficients of thin films, two different measuring systems are required. Here, we propose the improved method for the evaluation of these two coefficients with single equipment and with the relatively convenient procedure. The two-step loading process of applying the both positive and the negative pressure has been designed to acquire the piezoelectric coefficients. These results have beer calibrated for both the longitudinal and the transverse piezoelectric d-coefficients, d$\sub$33/ and d$\sub$31/, of thin films. In the first stage of the experiments, we have obtained d$\sub$33/ of 108pC/N and d$\sub$31/ of 57pC/N for the PZT thin films.

• Journal of Nutrition and Health
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• 제26권4호
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• pp.405-413
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• 1993

The longitudinal changes on human milk volume of 27 Korean lactating women (primiparae=10, multiparac=17) from 0.5 to 6 months after parturition have been studied by test-weighing method in Cheongju and Anseong area. The human milk volume per day increased to 2 months postpartum, and then decreased during lactation. The mean volume(g/day) at 0.5, 1, 2, 3, 4, 5, and 6 months were 634, 810, 847, 840, 844, 810, and 732g, respectively. The average volume were 791 ($\pm$149) and 786($\pm$131)g for primiparae and multiparae, respectively. The overall mean volume was 788$\pm$135g/day. The distributions of the individual mean volume during the first 6 months of lactation were found 450~549g(3.7%), 550~649g(11.1%), 650~749g(22.2%), 750~849%(37.1%), 850~949g(18.6%), 950~1049g(3.7%), and 1050~1149g(3.7%). The mean volume between primiparae and multiparase was significantly lower than other periods. The peak milk volume during the lactation was observed at 3 months postpartum for primiparae(40%), 2 months postpartum for multiparae(35.3%), and 2 months postpartum for total lactating women(29.6%). The volume of human milk had a significant positive correlation with peak volume and infant milk intake, but no correlation with maternal age, weight before delivery, height, and birth weight.

• Animal Systematics, Evolution and Diversity
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• 제36권3호
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• pp.251-257
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• 2020

The genus Plectus Bastian, 1865 represents a group of free-living freshwater nematodes belonging to the family Plectidae Örley, 1880. However, only one species has been reported thus far from Korea. Plectus aquatilis Andrássy, 1985 and Plectus cirratus Bastian, 1865 are reported for the first time from Korea, from sediments collected from the Nakdong River. Plectus aquatilis is distinguished from other Plectus species by its three longitudinal alae in the lateral field, thin and directed cephalic setae, continuous lip region (head not set-off), and rectangular shaped tail. Plectus cirratus is distinguished from other Plectus species by its large body, two longitudinal alae in the lateral field, larger stoma, and longer tail. Morphological characters and measurements of the specimens generally agree with the original descriptions of Plectus species. Here, the morphological characters (detailed morphometrics) of two species in the genus Plectus are fully redescribed and illustrated using optical microscopy. DNA barcode sequence information from the 18S rDNA gene is also provided for molecular species identification and compared with sequences from other Plectus species available on GenBank.

• 한국보육지원학회지
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• 제17권5호
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• pp.83-103
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• 2021

Objective: This study aimed to develop a longitudinal predictive model that identifies first-grade children who are at risk for ADHD and to investigate the factors that predict the probability of belonging to the at-risk group for ADHD by using machine learning. Methods: The data of 1,445 first-grade children from the 1st, 3rd, 6th, 7th, and 8th waves of the Korean Children's Panel were analyzed. The output factors were the at-risk and non-risk group for ADHD divided by the CBCL DSM-ADHD scale. Prenatal as well as developmental factors during infancy and early childhood were used as input factors. Results: The model that best classifies the at-risk and the non-risk group for ADHD was the LASSO model. The input factors which increased the probability of being in the at-risk group for ADHD were temperament of negative emotionality, communication abilities, gross motor skills, social competences, and academic readiness. Conclusion/Implications: The outcomes indicate that children who showed specific risk indicators during infancy and early childhood are likely to be classified as being at risk for ADHD when entering elementary schools. The results may enable parents and clinicians to identify children with ADHD early by observing early signs and thus provide interventions as early as possible.

• 한국초등과학교육학회지:초등과학교육
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• 제27권4호
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• pp.356-370
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• 2008

The study aims to explore sequence of earth science content in elementary school science curriculum in Korea and the U.S.. The analysis is focused on a) general content structure of earth science part; b) concept relationship between grades in the specific field of 'geology'; c) longitudinal connection of concepts and content in 'geology.' The findings are as follows. First, earth science curriculum content in Korea is structured according to sub-scientific disciplines centering on not science concepts but topics or inquiry activities whereas the U.S. curricular content is organized through integrative earth science topics with basic concepts and sub-concepts. Second, it is a common feature that basic concepts are interrelated to sub-concepts in all grades in both countries. However, basic concepts are scattered all over the grades, presented in a linear pattern in Korea while those are provided together in 3rd grade and repeated with extended concepts in a spiral structure in the U.S.. Last, it is not clear how concepts and content are longitudinally connected between grades in Korean curriculum. On the contrary, concepts and content in the U.S. curriculum have a strong longitudinal connection between grades with conceptual hierarchy. Such results indicate that Korean elementary school science curriculum would limit students' comprehensive understanding of science concepts through grades. The study suggests Korean science content should strengthen interrelationship among concepts as well as longitudinal connection between grades, in order to achieve the ultimate goal of science education, 'scientific literacy'.

• 한국도로학회논문집
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• 제16권4호
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• pp.1-9
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• 2014

PURPOSES: The objective of this study is to evaluate construction issues and design for transverse steel in continuously reinforced concrete pavement(CRCP). METHODS : The first continuously reinforced concrete pavement(CRCP) design procedure appeared in the 1972 edition of the "AASHTO Interim Guide for Design of Pavement Structures", which was published in 1981 with Chapter 3 "Guide for the Design of Rigid Pavement" revised. A theory that was accepted at that time for the analysis of steel stress in concrete pavement, called subgrade drag theory(SGDT), was utilized for the design of reinforcement of CRCP - tie bar design and transverse steel design - in the aforementioned AASHTO Interim Guide. However SGDT has severe limitations due to simple assumptions made in the development of the theory. As a result, any design procedures for reinforcement utilizing SGDT may have intrinsic flaws and limitations. In this paper, CRCP design procedure for transverse steel was introduced and the limitations of assumptions for SGDT were evaluated based on various field testing. RESULTS: Various field tests were conducted to evaluate whether the assumptions of SGDT are reasonable or not. Test results show that 1) temperature variations exist along the concrete slab depth, 2) very little stress in transverse steel, and 3) warping and curling in concrete slab from the field test results. As a result, it is clearly revealed out that the assumptions of SGDT are not valid, and transverse steel and tie bar designs should be based on more reasonable theories. CONCLUSIONS : Since longitudinal joint is provided at 4.1-m spacing in Korea, as long as joint saw-cut is made in accordance with specification requirements, the probability of full-depth longitudinal cracking is extremely small. Hence, for transverse steel, the design should be based on the premise that its function is to keep the longitudinal steel at the correct locations. If longitudinal steel can be placed at the correct locations within tolerance limits, transverse steel is no longer needed.

• 한국조사연구학회지:조사연구
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• 제7권2호
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• pp.97-122
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• 2006

2006년에 제1차 본조사에 들어간 '고령화연구패널조사(KLoSA)'는 HRS(미국), SHARE(유럽), ELSA(영국) 등과 연구네트워크를 구축하여 데이터베이스 사업과 공동연구를 추진하고 있다. '고령화연구패널조사'는 국가간 비교연구가 가능한 자료를 생산하기 위해서 다음 세 가지 조건을 고려하여 설계되었다. 첫째, 가족, 건강, 고용, 소득, 자산, 주관적 기대감 등 비교대상으로 삼은 조사들의 핵심적인 주제와 주요 조사영역을 일치시켰다. 둘째, 주요영역의 세부 항목은 우리나라의 제도적, 문화적 차이를 반영하도록 설계하였다. 우리나라의 공적연금과 의료보장제도의 특성 등 제도적 특성을 반영하여 설문을 구성하였으며, 고용상의 관행이나 금융상품의 범위도 고려하였다. 또한 문화적 차이에서 발생하는 가족간의 경제적 지원양태의 특징이나 재산관리상의 특성을 반영하도록 설문을 구성하였다. 마지막으로 척도의 선정에 있어서도 우리나라 고령자들에게 정확하게 의미가 전달할 수 있으면서도 국가간 비교연구도 가능한 방식의 척도를 개발하기 위하여 노력하였다.

• Journal of the Korean Data and Information Science Society
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• 제25권5호
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• pp.987-998
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• 2014

본 연구에서는 우리나라 환경부에서 최근에 구축한 아동 동집단 경시적 자료인 아동 건강과 환경 연구 (CHEER) 자료에 기초하여 주의력 결핍 과잉행동 장애 (ADHD)와 혈중 납 농도의 상관을 선형혼합모형을 사용하여 규명하고, CHEER 자료의 경시적 특성으로 나타나는 ADHD 점수의 "평균으로의 회귀" 현상을 보고하고자 한다. 또한 ADHD를 종점으로 한 혈중 납 농도의 용량-반응 곡선을 도출하며, 이렇게 도출된 용량-반응 곡선에 기초하여 몇 가지 상황 하에서 독성기준치인 벤치마크 용량 하한 (BMDL)을 유도한다.