• 제목/요약/키워드: longitudinal studies

검색결과 933건 처리시간 0.021초

The Reciprocal Causal Relationship between Social Activities and Health with Reference to the Cognitive Function Level among Community-dwelling Older Adults: A Cross-Lagged Panel Analysis

  • Kim, Da Eun;Yoon, Ju Young
    • 지역사회간호학회지
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    • 제28권1호
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    • pp.13-22
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    • 2017
  • Purpose: The aim of this study is to examine the reciprocal causal relationship between social activities and health with reference to the cognitive function level among community-dwelling older adults. Methods: We conducted a longitudinal data analysis using the $4^{th}$ (Time 1) and $5^{th}$ (Time 2) waves from the Korean Longitudinal Study of Ageing adopting cross-lagged panel analysis (CLPA). Results: A total of 3,473 community-dwelling older adults were included in the analysis: 2,053 in the normal cognitive function group, 912 in the mild cognitive impairment group, and 508 in the moderate to severe cognitive impairment group. The CLPA revealed that higher levels of social activities at Time 1 significantly influenced better subjective health perception at Time 2 in all three groups. In addition, better subjective health perception at Time 1 significantly influenced higher levels of social activities at time 2 only in the normal cognitive function group. Conclusion: This study demonstrates that participating in social activities has positive effects on health regardless of the cognitive function level in community-dwelling older adults. This finding suggests that there is a need to develop strategies that can be used to encourage older adults with cognitive decline to maintain participation in social activities.

Quadratic inference functions in marginal models for longitudinal data with time-varying stochastic covariates

  • Cho, Gyo-Young;Dashnyam, Oyunchimeg
    • Journal of the Korean Data and Information Science Society
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    • 제24권3호
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    • pp.651-658
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    • 2013
  • For the marginal model and generalized estimating equations (GEE) method there is important full covariates conditional mean (FCCM) assumption which is pointed out by Pepe and Anderson (1994). With longitudinal data with time-varying stochastic covariates, this assumption may not necessarily hold. If this assumption is violated, the biased estimates of regression coefficients may result. But if a diagonal working correlation matrix is used, irrespective of whether the assumption is violated, the resulting estimates are (nearly) unbiased (Pan et al., 2000).The quadratic inference functions (QIF) method proposed by Qu et al. (2000) is the method based on generalized method of moment (GMM) using GEE. The QIF yields a substantial improvement in efficiency for the estimator of ${\beta}$ when the working correlation is misspecified, and equal efficiency to the GEE when the working correlation is correct (Qu et al., 2000).In this paper, we interest in whether the QIF can improve the results of the GEE method in the case of FCCM is violated. We show that the QIF with exchangeable and AR(1) working correlation matrix cannot be consistent and asymptotically normal in this case. Also it may not be efficient than GEE with independence working correlation. Our simulation studies verify the result.

영아기 기질 및 부모의 양육행동에 따른 2-4세 아동의 행동억제에 관한 단기종단연구 -8개국 비교문화연구를 위한 기초 연구- (A Short-term Longitudinal Study on Infant Temperament, Parenting Behavior and 2-4 Year Behavioral Inhibition: A Korean sample for 8 cross-cultural studies)

  • 정옥분;;박성연;윤종희;도현심
    • 가정과삶의질연구
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    • 제21권3호
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    • pp.29-38
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    • 2003
  • A three-year longitudinal design was employed to ascertain whether different types of behavioral inhibition(i.e. traditional, peer-social) were stable from toddler to preschool age(2-4 year), and whether inhibited temperament and/or parenting style would independently and interactively predict children's subsequent social and behavioral outcomes. At time 1, 113 toddlers (55 males, 58 females) and their mothers were observed in the traditional inhibition paradigm. At time 2, 36 4-year-old children were observed with unfamiliar peers in the nontraditional inhibition paradigm. Maternal ratings of psychological functioning of children and maternal behaviors were also obtained for both time 1 and 2. Results showed that behavioral inhibition was not stable from toddler to preschool age. Maternal authoritative behaviors at age 2 were negatively associated with preschooler's social reticence. Toddler's behavioral inhibition was negatively associated with maternal authoritative behaviors at age 4. In a cross-lag correlation analysis, maternal authoritative behaviors appeared to affect child's behavioral inhibition more strongly than the other way around.

Improvement of the behaviour of composite slabs: A new type of end anchorage

  • Fonseca, Alexandre;Marques, Bruno;Simoes, Rui
    • Steel and Composite Structures
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    • 제19권6호
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    • pp.1381-1402
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    • 2015
  • The application of composite steel-concrete slabs with profiled steel sheeting has increased, due to the various advantages in relation to reinforced concrete slabs such as, the reduced thickness, the reduced amount of lost formwork needed, as well as the speed of execution. The loss of longitudinal shear resistance is, generally, the governing design mode for simply supported spans of common lengths. For common distributed loadings, the composite behaviour is influenced by the partial shear connection between the concrete and the steel sheeting. The present research work is intended to contribute to improving the ultimate limit state behaviour of composite slabs using end anchorage. Eurocode 4, Part 1.1 (EN 1994-1-1) provides an analytical methodology for predicting the increase of longitudinal resistance, achieved by using shear studs welded through the steel sheeting as the end anchorage mechanism. The code does not supply an analytical methodology for other kinds of end anchorage so, additional tests or studies are needed to prove the effectiveness of these types of anchorage. The influence of end anchorage mechanisms provided by transverse rebars at the ends of simply supported composite slabs is analysed in this paper. Two experimental programmes were carried out, the first to determine the resistance provided by the new end anchorage mechanism and the second to analyse its influence on the behaviour of simply supported composite slabs.

유연근무제도가 기혼여성의 일-가정 갈등 및 촉진, 직무만족에 미치는 영향: 패널분석 방법을 이용하여 (The effects of flexible work arrangements on work-family conflict and facilitation, and job satisfaction for married working women: A longitudinal analysis)

  • 한영선;정영금
    • 가족자원경영과 정책
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    • 제18권4호
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    • pp.1-26
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    • 2014
  • This study analyzes the effects of the three types of flexible work arrangements (part-time, flexitime, and reduced working hours for childcare) available in Korea on work-family conflict, facilitation, and job satisfaction for married working women ages 15-49. The study employs a panel analysis based on the first to the fourth data from the Korean Longitudinal Survey of Women & Families (KLoWF). The major results are as follows. First, the availability of part-time jobs and reduced working hours to facilitate childcare is significantly related to work-family conflict for married women. If a married woman is employed in a part-time position or if reduced working hours for childcare are available, the conflict within the family caused by the job is reduced. Second, none of the three types of flexible work arrangements have a statistically significant influence on work-family facilitation for married women. Third, the availability of reduced working hours for childcare has a positive effect on the job satisfaction of married women. In conclusion, flexible working hours for women who are raising children are the main factor in reducing the negative effect of a job on a woman's family life as they contribute to work and family compatibility.

스웨덴 노인용 코하우징 주민의 이주동기의 시계열적 차이 : 2001~2010년 10년간의 차이를 중심으로 (Difference of Motivation of Move to Swedish Senior Cohousing by Longitudinal Analysis : Focus on Differences between the Years of 2001 and 2010)

  • 최정신
    • 가정과삶의질연구
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    • 제31권3호
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    • pp.81-92
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    • 2013
  • The purpose of this study is to identify difference in motivation of move to senior cohousing communities in Sweden during 10 years between the year of 2001 and 2010 by a longitudinal study. Questionnaire survey was used for the study. 313 data were collected from 12 senior cohousing communities, which were established by residents-initiated process. It includes 8 of Senior g${\aa}$rden cohousings in 2001 and 4 of +40 cohousings in 2010 nationwide in Sweden. The result indicates that there are significant differences in motivation of move to senior cohousing between 2001 and 2010. Comparing motivation of move to senior cohousing during 10 years, respondents of 2010 focus more on social merits than practical merits of cohousing as they move to cohousing communities. They stress more to the reasons as good contacts with neighbors, mutual supports, sharing common activities and getting rid of loneliness rather than burden of housing and garden management, and universal-designed house. The result of this study reveals motivation of move to senior cohousing has been changed during 10 years in Sweden.

추나요법을 적용한 후종인대골화증을 동반한 경추척추관협착증 환자의 경과관찰 1례 (A Case Report on Cervical Spinal Stenosis with Ossification of posterior Longitudinal Ligament Applied Chuna Treatment)

  • 이진복;이휘용;조이현;정시영
    • 척추신경추나의학회지
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    • 제4권1호
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    • pp.85-94
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    • 2009
  • Objects : This study was to report a clinical effect of Korean Treatment for a patient diagnosed by Computed Tomography as Cervical Spinal Stenosis with Ossification of posterior Longitudinal Ligament. Methods : In order to alleviate left shoulder pain and neck stiffness, the patient was treated by acupuncture therapy, herbal medicine, distilled herbal injection, cervical traction technique of Chuna treatment and conservative managements. To evaluate the effect of the treatment, Recovery rate of Hirabayashi, VAS(Visual Anlaogue Scale), NDI and ROM(Range of Motion) were used. Lhermitte's sign, Valsalva test, Distraction test, Compression test and Spurling test were carried out. Results : VAS, NDI and ROM were improved and Recovery rate was 100%. Conclusions : Korean Treatment can be effectively used for a patient with Cervical Spinal Stenosis with OPLL. Further clinical studies are needed to verify the findings.

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A Probabilistic Corrosion Rate Estimation Model for Longitudinal Strength Members of Bulk Carriers

  • Paik, Jeom-Kee;Kim, Sung-Kyu;Lee, Sang-Kon;Park, Young-Eel
    • Journal of Ship and Ocean Technology
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    • 제2권1호
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    • pp.58-70
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    • 1998
  • Many bulk carrier losses have been reported of late, and one of the possible causes of such casualties is thought to be the structural failure of aging hulls in rough weather. Clearly, in such cases, vessels that start out belong adequate somehow become marginal later in life. Fatigue and corrosion related potential problems may be the most important factors affecting such age related vessel damage. With respect to fatigue, extensive studies have been done worldwide both experimentally and theoretically, and the results have been applied to some extent. However, in the case of corrosion effects, additional research is still needed to better understand, clarify and address the various strength uncertainties and their effects on structural behavior. This paper develops a probabilistic corrosion rate estimation model for the longitudinal strength members of bulk carriers. The model is based on available statistical data for corrosion of existing bulk carriers. The corrosion data collected are documented for future use.

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기하학적 변위 이론을 적용한 VLCC 최종종강도 평가 (Assessment of Ultimate Longitudinal Strength of a VLCC considering Kinematic Displacement Theory)

  • 정준모;남지명;;윤성원;이강수
    • 대한조선학회논문집
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    • 제50권4호
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    • pp.255-261
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    • 2013
  • This paper presents prediction of ultimate longitudinal strength of a VLCC, "Energy Concentration" for which many benchmark studies have been carried out, based on kinematic displacement method proposed by Tayyar and Bayraktarkatal (2012). Kinematic displacement theory provides semi-analytical solution of average compressive strengths for various kinds of stiffened panels. The accuracy of average compressive strengths obtained from formulas of CSR(common structural rules) for tankers and kinematic displacement method are discussed in the fore part of this paper. Hull girder ultimate strengths using Smith method are also compared for different average compressive strengths. By comparing them with other benchmark results, it is concluded that the new method provides lower bounds, because hull girder strengths under the sagging and hogging moment conditions approach nearly lower bounds.

데이터 누적을 이용한 반사도 지역 지도 생성과 반사도 지도 기반 정밀 차량 위치 추정 (Intensity Local Map Generation Using Data Accumulation and Precise Vehicle Localization Based on Intensity Map)

  • 김규원;이병현;임준혁;지규인
    • 제어로봇시스템학회논문지
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    • 제22권12호
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    • pp.1046-1052
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    • 2016
  • For the safe driving of autonomous vehicles, accurate position estimation is required. Generally, position error must be less than 1m because of lane keeping. However, GPS positioning error is more than 1m. Therefore, we must correct this error and a map matching algorithm is generally used. Especially, road marking intensity map have been used in many studies. In previous work, 3D LIDAR with many vertical layers was used to generate a local intensity map. Because it can be obtained sufficient longitudinal information for map matching. However, it is expensive and sufficient road marking information cannot be obtained in rush hour situations. In this paper, we propose a localization algorithm using an accumulated intensity local map. An accumulated intensity local map can be generated with sufficient longitudinal information using 3D LIDAR with a few vertical layers. Using this algorithm, we can also obtain sufficient intensity information in rush hour situations. Thus, it is possible to increase the reliability of the map matching and get accurate position estimation result. In the experimental result, the lateral RMS position error is about 0.12m and the longitudinal RMS error is about 0.19m.