• 제목/요약/키워드: Longitudinal Data Analysis

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도서관 성과 측정을 위한 잠재성장모형 적용에 관한 연구 (A Study on the Application of Latent Growth Model for Measuring the Outcomes of Library)

  • 박성재;한상우;조세홍
    • 한국문헌정보학회지
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    • 제52권4호
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    • pp.179-194
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    • 2018
  • 본 연구의 목적은 도서관의 성과를 측정하기 위해서 잠재성장모형을 적용하고 그 활용가능성을 논하는 것이다. 도서관의 성과를 측정하기 위하여 도서관 활동에 대한 데이터, 즉 이용자의 대출 데이터를 이용하였다. 시간에 따른 변화를 담고 있는 종단자료를 분석하기 위한 통계적인 모형으로 잠재성장모형을 이용하였다. 서울 소재 공공도서관의 2010년부터 2014년까지의 95,962명의 이용자의 대출데이터를 무조건모형, 조건모형, 혼합성장모형을 적용하여 대출의 특성을 분석하였다. 분석결과, 대출량은 절편요인이 4.19, 기울기요인이 0.24의 선형성장을 보였다. 성별에 따른 차이분석에서 큰 차이를 보이지 않았으나 4개의 그룹으로 나누었을 때, 10세 미만의 어린이의 대출 패턴이 급속히 증가하는 추세를 보였다. 향후 문헌정보학 분야에서 종단연구자료를 분석할 때, 잠재성장모형이 활용될 것으로 기대된다.

인구사회학적 요인 및 건강관련 특성에 따른 인지기능저하 관련 요인 연구 -고령화연구패널 조사 자료를 이용하여- (Factors Related to Cognitive Function Decline by Socio-demographic and Health-related Characteristics : Based on Korean Longitudinal Study of Ageing(KLoSA) Panel Data)

  • 김경나;이효영;김수정
    • 보건의료산업학회지
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    • 제14권1호
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    • pp.137-146
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    • 2020
  • Objectives: The aim of this study was to investigate cognitive function decline by socio-demographic and health-related characteristics (health behaviors and health status) using 5th Korean Longitudinal Study of Aging panel data. Methods: The subjects were 4,440 community-dwelling people aged over 57 years. The data were analyzed with descriptive statistics, frequency analysis, χ2-test, and binary logistic regression analysis using SPSS ver. 25.0. Results: The findings revealed that socio-demographic characteristics (gender, age, area of residence, educational level, marital status, number of children, number of grand-children) and health-related characteristics (smoking, drinking, regular exercise, weight category by body mass index, hypertension and diabetes mellitus) were factors that influenced cognitive function decline (p<.05). Conclusions: Cognitive function decline was closely related to health behaviors and disease types. Future studies must examine related constructs to accurately determine these relationships among various populations. The present study could be used as a tool for the development and implementation of health promotion and prevention strategies.

사장교 콘크리트 주탑의 온도영향 평가 (Evaluation of Thermal Effect on the Concrete Pylon of a Cable-stayed Bridge)

  • 박종칠;김영진;최성권;이충표
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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    • pp.355-358
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    • 2005
  • In this paper, an actual behavior of the pylon of Seohae Grand Bridge which is a cable stayed bridge and has been constructed 4 years ago was analyzed by using data acquisition system. As a result, the pylon of cable stayed bridge behaved normally with respect to the change of temperature. The annual displacement of the top of pylon(PY1) ranged from -71.4mm to +181.7mm in the longitudinal direction of the bridge. In the case of the longitudinal displacement, the displacement of PY1 was bigger than that of PY2 because PY1 is movable and PY2 is fixed in terms of the constraint condition of super structure. For the long term, PY1 will be sloped gently to the direction of Dangjin and PY2 will be also sloped gently to the direction of Pyongtaek by the effect of creep and shrinkage in the case of the longitudinal direction. The result of structural analysis showed good agreement with the result mentioned above.

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Three-dimensional morphometric study on the retromolar pad

  • Min-Sang Cha;Dae-Gon Kim;Yoon-Hyuk Huh;Lee-Ra Cho;Chan-Jin Park
    • The Journal of Advanced Prosthodontics
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    • 제15권6호
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    • pp.302-314
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    • 2023
  • PURPOSE. The aim of this study was to classify the shapes of retromolar pads and assess their morphometric differences using a 3D model. MATERIALS AND METHODS. Two hundred fully edentulous or Kennedy Class I partially edentulous patients (400 retromolar pads) were enrolled. Scan data of the definitive mandibular casts produced through functional impressions were obtained using a 3D laser scanner. Seven parameters (transverse diameter, longitudinal diameter, transverse-contour length, longitudinal-contour length, longitudinal/transverse diameter ratio, longitudinal/transverse-contour length ratio, and angle of the retromolar pad line to the residual alveolar ridge line) were measured using image analysis software. Subsequently, the pads were classified according to the shape. Statistical analyses were performed using 95% confidence intervals. RESULTS. Classifying the retromolar pads into three shapes led to high intra-examiner reliability (Cronbach's alpha = 0.933). The pear shape was the most common (56.5%), followed by oval/round (27.7%) and triangular (15.8%) shapes. There were no significant differences between the left and right sides according to the shape and no significant differences in any parameter according to age. The transverse diameter and longitudinal/transverse diameter ratio differed between sexes (P < .05). The triangular shape had a significantly different transverse diameter, transverse-contour length, longitudinal/transverse diameter ratio, and longitudinal/transverse-contour length ratio compared with the pear and oval/round shapes (P < .05). CONCLUSION. From a clinical reliability standpoint, classifying retromolar pads into three shapes (oval/round, pear-shaped, and triangular) is effective. The differences in the sizes among the shapes were attributed to the transverse measurement values.

전류에 관한 학생들의 오인 유형변화의 종단적 연구 (A Longitudinal Study on Students' Misconception patterns of Electric Current)

  • 문충식;권재술
    • 한국과학교육학회지
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    • 제11권1호
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    • pp.1-14
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    • 1991
  • The objectives of the study is to examine students concepts changes using a longitudinal study. The study compared two data sets collected in 1989 and in 1990 using the same instrument and subjects. The first data set was collected by Ahn(Ahn, 1989). In the study, students' patterns of misconceptions were examined in the following aspects : 1) Comparison of the students' misconception before observation of actual phenomenon in the first data between the two data sets. 2) The analysis of the patterns of students misconceptions of the second data set In terms of students' patterns of conceptual change before and after observation in the first data set. In the study, overall patterns of students' misconceptions appeared in the second data set were similar to those of the first data set ; however, about 40% of individual student's patterns of misconceptions were changed. Even the students who changed their opinion from misconception to scientific by observing the give phenomenon in the previous study(the first data set) returned to their original misconception after one year. The researcher interpreted this phenomenon in terms of the characteristics of the three kinds of cognitive conflict suggested by Kwon(Kwon, 1989).

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Applications of response dimension reduction in large p-small n problems

  • Minjee Kim;Jae Keun Yoo
    • Communications for Statistical Applications and Methods
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    • 제31권2호
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    • pp.191-202
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    • 2024
  • The goal of this paper is to show how multivariate regression analysis with high-dimensional responses is facilitated by the response dimension reduction. Multivariate regression, characterized by multi-dimensional response variables, is increasingly prevalent across diverse fields such as repeated measures, longitudinal studies, and functional data analysis. One of the key challenges in analyzing such data is managing the response dimensions, which can complicate the analysis due to an exponential increase in the number of parameters. Although response dimension reduction methods are developed, there is no practically useful illustration for various types of data such as so-called large p-small n data. This paper aims to fill this gap by showcasing how response dimension reduction can enhance the analysis of high-dimensional response data, thereby providing significant assistance to statistical practitioners and contributing to advancements in multiple scientific domains.

노인의 사회적 배제 수준의 변화유형과 예측요인: 영국고령화패널(ELSA)분석 (Patterns of the Change and the Predictors of the Social Exclusion of the Older People: Analysis of English Longitudinal Study of Ageing(ELSA))

  • 박현주;정순둘
    • 한국노년학
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    • 제32권4호
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    • pp.1063-1086
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    • 2012
  • 본 연구는 종단적인 분석을 통하여 노인의 사회적 배제 수준 변화 양상에 따른 유형을 살펴보며 그 예측요인을 밝힘으로써 노인의 사회적 배제 상황을 파악하고자 하였다. 이를 위하여 본 연구는 영국고령화패널(ELSA)의 2002-03년의 제 1차 조사부터 2008-09년 제 4차 조사까지 2년 주기로 하여 네 차례에 걸쳐 반복 측정한 자료를 사용하였으며, 표본유지율을 고려하여 50세 이상의 남녀 7631명의 자료를 최종 분석에 사용하였다. 노인의 사회적 배제는 사회적 관계망, 문화 및 여가 활동, 의료서비스 접근, 재정적 안정, 정서적 배제 영역의 다섯 개의 하위 영역으로 구분되어 분석되었다. 자료의 분석을 위하여 다양한 질적인 차이를 밝히는데 목적을 두는 관찰대상 중심적 접근이 시도되었으며, 이는 변화궤적을 유형화하는 준모수적 집단중심 모형을 통해 분석되었다. 분석을 통하여 노인들은 유사한 배제 수준을 보이면서 동일하게 변화하는 '동질적' 집단이 아니라, 다양한 초기값과 변화율을 보이는 다양한 유형으로 구분될 수 있음이 밝혀졌다. 뿐만 아니라 변화궤적의 유형화를 통하여 문화여가활동을 제외하고 모든 영역에서 노인의 사회적 배제 수준이 시간 경과에 따라 천천히 증가하거나 유지됨을 확인하였다. 준모수적 집단중심 모형의 결과를 통하여 지속적으로 높은 배제 수준을 유지하거나 높은 수준에서 증가하는 유형을 사회적 배제의 고위험군으로 판단하여 선별해 낼 수 있었다. 또한 고위험군에 속하는 노인들의 특성을 밝히기 위해 다항로지스틱 분석을 실시한 결과, 노인의 사회적 배제에 영향을 주는 주요 변수는 성별, 연령, 건강상태, 활동능력, 소득, 결혼상태, 가족관계, 수급여부 등으로 나타났다.

Finite element analysis of longitudinal reinforcement beams with UHPFC under torsion

  • Mohammed, Thaer Jasim;Bakar, B.H. Abu;Bunnori, N. Muhamad;Ibraheem, Omer Farouk
    • Computers and Concrete
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    • 제16권1호
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    • pp.1-16
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    • 2015
  • The proposed techniques to strengthen concrete members such as steel plates, polymers or concrete have important deficiencies in adherence and durability. The use of UHPFC plates can overtake effectively these problems. In this paper, the possibility of using UHPFC to strengthen RC beams under torsion is investigated. Four specimens of concrete beams reinforced with longitudinal bars only were tested under pure torsion. One of the beams was considered as the baseline specimen, while the others were strengthened by ultra-high-performance fiber concrete (UHPFC) on two, three, and four sides. Finite element analysis was conducted in tandem with experimental work. Results showed that UHPFC enhances the strength, ductility, and toughness of concrete beams under torsional load, and that finite element analysis is in good agreement with the experimental data.

양축식 선형유도 전동기의 2차원 자속분포 해석에 관한 연구 (A Study on the 2-Dimensional Flux Distribution Analysis of a Double Sided Linear Induction Motor)

  • 임달호;김학린;조윤현
    • 대한전기학회논문지
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    • 제39권1호
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    • pp.29-35
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    • 1990
  • This paper proposes a tow-dimensional magnetic flux distribution analysis of the double-sided linear induction motor(DLIM). Both the longitudinal end-effect and the transverse edge-effect, which are due to the finite length and width of the primary stator, are considered. Also each force which is due to the variation of slip frequency was computed to show the fact that the thrust force of DLIM is dependent on both the longitudinal end-effect and the transverse edge-effect. To ascertain the propriety of this analysis, the simulated results of the magnetic flux density distribution in the airgap are compared to the experimental data.

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혈액투석 환자의 건강상태 예측요인: 2년 종단연구 (Predictors of Health Status in Patients with Hemodialysis: A Two-year Longitudinal Study)

  • 차지은
    • 임상간호연구
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    • 제22권3호
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    • pp.359-367
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    • 2016
  • Purpose: The purpose of this study was to examine the effects of physical, psychological, and social factors on the health status of patients undergoing hemodialysis using longitudinal data. Methods: Two surveys were conducted within a period of two-year. A total of 75 patients participated in both surveys. Eight variables including symptoms, treatment belief, hope, meaning-focused coping, family support, friend/peer support, healthcare provider support, and health status were measured. Data were analyzed by paired t-test, Pearson's correlation coefficients, and hierarchical multiple regressions. Results: The mean age of the participants was 47.31 and the average duration of dialysis was 8.27 years. There was no difference in scores on perceived health status between the two year-interval surveys. The two-year follow-up on perceived health status was correlated with baseline perceived health status, friend/peer support, meaning-focused coping, hope, and symptoms. As the result of the regression analysis, friends/peer support (${\beta}=.31$, p=.013) and baseline perceived health status (${\beta}=.30$, p=.020) were found to be significant predictors of subsequent health status which explained 39.0% of the variance. Conclusion: This study suggests the importance of psychosocial resources for positive health outcomes in patients with a chronic illness. Nursing interventions aimed to provide renal peer support need to be developed and tested.