• 보건교육건강증진학회지
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• 제30권5호
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• pp.1-13
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• 2013

Objectives: While many studies have been conducted on whether smoking scenes in films actually affect audience members' smoking, a comprehensive conclusion has yet to be derived. This study systematically reviewed the effect of smoking scenes in films on audience members' attitudes, beliefs, and actions. Methods: We analyzed a total of 146 studies searched on PubMed and PsycINFO (41 qualitative studies, 72 cross-sectional studies, 20 longitudinal studies, and 13 experimental studies). Results: Whereas qualitative studies have only demonstrated that audience members tend to perceive smoking scenes in films not as negative information but as positive information, cross-sectional studies have reported a significant association between smoking scenes and smoking behavior notwithstanding the problems of classifying the groups studied and measuring the degree of exposure. Through follow-up observations, longitudinal studies have reported that such media exposure can serve as a predictor of future smoking. Finally, with exposure and confounding variables under control, experimental studies have confirmed that smoking scenes in films indeed affect audience members' attitudes, beliefs, and actions regarding smoking. Conclusions: Scenes of actors and actresses smoking can be imitated or learned through audience members' immersion and identification and reproduce positive images that may render smoking socially acceptable.

• Asia pacific journal of information systems
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• 제25권4호
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• pp.746-762
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• 2015

This study developed a conceptual model that integrated psychological and physical reactions resulting from online tourism reviews through a longitudinal trust-satisfaction model (LSTM) developed based on the extended valence framework and expectation-confirmation theory. Online reviews are essential factor of consumer's purchase decision. This phenomenon is well applied in a tourism context. However, investigations on online reviews in a longitudinal approach in a tourism context are quite limited. Therefore, this study suggests a conceptual model based on LTSM and several propositions about how online tourism reviews, which are divided into factual and experiential reviews, influence the future travelers' perceptions and attitudes, such as expectation, confirmation, and destination loyalty, in a longitudinal format by examining previous related studies. Finally, expected results were discussed and several implications were described theoretically and practically.

• 한국강구조학회 논문집
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• 제14권6호
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• pp.683-690
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• 2002

본 연구에서는 국내에 적용된 강바닥판의 데크플레이트와 종리브 현장 연결 스캘럽부의 구조상세를 검토하고 실험체를 제작하여 정적재하실험 및 피로실험을 실시하였다. 또한 FEM 해석을 통하여 스캘럽 길이, 스캘럽 곡률반경, 데크플레이트 두께 등과 같은 매개변수가 종리브 스캘럽부의 응력에 미치는 영향을 살펴보았으며, 이를 통하여 스캘럽부에 대한 S-N선도를 추정하였다. 피로실험을 수행한 결과, 낮은 응력수준에서는 스캘럽부에서 피로균열이 발생하였고, 높은 응력수준에서는 핸드홀 덮개판의 파괴 후에 종리브의 갑작스런 파괴가 일어났다. 피로실험결과를 JSSC 피로등급과 Shigley와 Juvinall이 제안한 방법에 의한 피로강도와 비교검토한 결과, 데크플레이트와 종리브 현장연결 스캘럽부는 규정된 피로등급를 만족하였다.

• Earthquakes and Structures
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• 제7권4호
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• pp.463-484
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• 2014

Solid piers with a rounded rectangular cross-section are widely used in railway bridges for high-speed trains in China. Compared to highway bridge piers, these railway bridge piers have a larger crosssection and less steel reinforcement. Existing material models cannot accurately predict the seismic behavior of this kind of railway bridge piers. This is because only a few parameters, such as axial load, longitudinal and transverse reinforcement, are taken into account. To enable a better understanding of the seismic behavior of this type of bridge pier, a simultaneous influence of the various parameters, i.e. ratio of height to thickness, axial load to concrete compressive strength ratio and longitudinal to transverse reinforcements, on the failure characteristics, hysteresis, skeleton curves, and displacement ductility were investigated. In total, nine model piers were tested under cyclic loading. The hysteretic response obtained from the experiments is compared with that obtained from numerical studies using existing material models. The experimental data shows that the hysteresis curves have significantly pinched characteristics that are associated with small longitudinal reinforcement ratios. The displacement ductility reduces with an increase in ratio of axial load to concrete compressive strength and longitudinal reinforcement ratio. The experimental results are largely in agreement with the numerical results obtained using Chang-Mander concrete model.

• 근관절건강학회지
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• 제8권2호
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• pp.278-286
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• 2001

With the aging of society a great deal of interest is being placed on the value of longitudinal data in evaluating physiological losses. We present data on test-one/test-two reliability and reproducibility for measures of training, bone density from a longitudinal study of master athletes. Fifty-two males (mean age at test $1=58.2{\pm}9.8\;years$) and thirty-two females ($54.4{\pm}8.8\;years$) were selected from the study population. Bone mineral density was determined using DEXA (Hologic 1500). The characteristics of the subjects are presented below as $means\;{\pm}\;S.D$. The data was imported into the Statistical Package for the Social Science (SPSS 9.0, Chicago, IL). Paired t-tests were performed between visit 1 and visit 2 in subjects. Pearson correlations were performed. The results of this study indicate the measures of training history, body mass and bone density are reasonably stable and reproducible. We conclude that body composition and bone density parameters are stable and reproducible over time in active older subjects. Physiologic measures in master athletes are fairly stable, and reproducible over time Longitudinal studies investigating age-related changes in master athletes need to be conducted on a time schedule of greater than two years.

• Human Ecology Research
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• 제59권3호
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• pp.341-351
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• 2021

The purpose of this study was to examine the longitudinal relationships between Korean adolescents'mobile phone dependency, trajectories of depression, and self-regulated learning abilities. To achieve these goals, structural equation modeling analysis was conducted, using the 3rd, 5th and 7th wave of the data on 4th graders taken from the Korean Children and Youth Panel Survey. The results can be summarized as follows. First, growth-curve longitudinal analysis indicates that depression in 6th through 10th grade has increased. Second, mobile phone dependency among adolescents at 6th grade has a significant effect on both the initial value and the rate of change in depression. Also, the initial value and the rate of change in depression have significant relationships with mobile phone dependency at 10th grade. Moreover, both increased levels of mobile phone dependency and the rate of change in depression significantly influence adolescents'self-regulated learning abilities at 10th grade. Based on a longitudinal data set, these findings demonstrate the causal relationships between Korean adolescents'trajectories of depression and their mobile phone dependency. The findings also provide a comprehensive framework with implications for adolescents'development through an understanding of the relationships between adolescents'depression and mobile phone dependency, which impact their self-regulated learning abilities.

• 응용통계연구
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• 제29권1호
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• pp.113-122
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• 2016

경시적 자료는 반복적으로 측정된 다변량 자료의 한 형태로 임상학, 보건학, 경제학에서 자주 발생된다. 시계열자료와 구분되는 가장 큰 특징은 표본수와 공변량 효과의 추정에 있다. 경시적 자료는 일반적으로 시계열 자료보다 더 큰 표본 개체로 이루어져 있으며 연구의 주 관심은 특정 공변량의 효과를 추정하는 데 있다. 또한 시계열 자료보다 반복 측정 횟수가 짧으며 개체마다 다른 관측 횟수와 다른 관측 중단 시점을 가질 수 있다. 본 연구에서는 관측 시점과 관측 종료 원인이 경시자료와 서로 연관된 경우에 결합 모형을 적용함으로써 이들간의 연관성을 분석하고자한다. 따라서 이들 변량간의 연관성을 모형화하기 위해 이변량 랜덤효과가 적용된다. 실제 자료 분석에서는 간경변증 환자의 핼액 응고 수치 시간을 관심 있는 경시적 자료로 환자가 병원 방문시점과 관측 중단원인들간의 상호 연관관계를 규명하고자 하였다. 특히, 중도 절단원인은 사망이나 간이식을 받는 사건일 때 발생하는데 본 연구에서는 사망 사건과의 연관성이 고려되었다. 결과를 통해 혈액 응고 시간이 길고 병원 방문 시점이 빈번할수록 사망할 가능성이 높음을 알수 있었다. 또한 혈액응고 시간이 길수록 병원 방문 횟수가 빈번하였다.

• Steel and Composite Structures
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• 제47권6호
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• pp.709-728
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• 2023

Experimental and analytical studies were conducted to clarify the influencing mechanisms of the longitudinal reinforcement on performance of axially loaded Reinforced Concrete-Filled Steel Tube (R-CFST) short columns. The longitudinal reinforcement ratio was set as parameter, and 10 R-CFST specimens with five different ratios and three Concrete-Filled Steel Tube (CFST) specimens for comparison were prepared and tested. Based on the test results, the failure modes, load transfer responses, peak load, stiffness, yield to strength ratio, ductility, fracture toughness, composite efficiency and stress state of steel tube were theoretically analyzed. To further examine, analytical investigations were then performed, material model for concrete core was proposed and verified against the test, and thereafter 36 model specimens with four different wall-thickness of steel tube, coupling with nine reinforcement ratios, were simulated. Finally, considering the experimental and analytical results, the prediction equations for ultimate load bearing capacity of R-CFSTs were modified from the equations of CFSTs given in codes, and a new equation which embeds the effect of reinforcement was proposed, and equations were validated against experimental data. The results indicate that longitudinal reinforcement significantly impacts the behavior of R-CFST as steel tube does; the proposed analytical model is effective and reasonable; proper ratios of longitudinal reinforcement enable the R-CFSTs obtain better balance between the performance and the construction cost, and the range for the proper ratios is recommended between 1.0% and 3.0%, regardless of wall-thickness of steel tube; the proposed equation is recommended for more accurate and stable prediction of the strength of R-CFSTs.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2005년도 춘계 학술발표대회 논문집
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• pp.318-319
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• 2005

• Steel and Composite Structures
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• 제12권3호
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• pp.261-273
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• 2012

This study proposes and examines a circular composite bridge pier for seismic resistance. The axial and flexural strengths of the proposed bridge pier are provided by the longitudinal reinforcing bars and the concrete, while the transverse reinforcements used in the conventional reinforced concrete pier are replaced by the steel tube. The shear strength of this composite pier relies on the steel tube and the concrete. This system is similar to the steel jacketing method which strengthens the existing reinforced concrete bridge piers. However, no transverse shear reinforcing bar is used in the proposed composite bridge pier. A series of experimental studies is conducted to investigate the seismic resistant characteristics of the proposed circular composite pier. The effects of the longitudinal reinforcing bars, the shear span-to-diameter ratio, and the thickness of the steel tube on the performance of strength, ductility, and energy dissipation of the proposed pier are discussed. The experimental results show that the strength of the proposed circular composite bridge pier can be predicted accurately by the similar method used in the reinforced concrete piers with minor modification. From these experimental studies, it is found that the proposed circular composite bridge pier not only simplifies the construction work greatly but also provides excellent ductility and energy dissipation capacity under seismic lateral force.