• 한국안전학회지
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• 제15권4호
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• pp.35-40
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• 2000

The influence of cyclic loading history on the creep behavior of the 30 vol% hot-pressed $SiC_f/Si_3N_4copmposite was experimentally investigated at $1200^{\circ}C$. The duration of loading/unloading had great effects on the creep behaviors. The short term duration cyclic loading history test results showed significant reduction in the primary and steady-state creep rates. For example, 300sec loading/300sec unloading history resulted in 70% lower steady-state creep rate than that of the continuous loading. However the long term duration cyclic loading history test results showed little change in creep rates compared to those of the continuous one. The reason for the significant change in the short term duration cycles was estimated due to the change in the stress redistribution between the fiber and matrix during the creep recovery in the primary stage.

• 한국융합학회논문지
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• 제10권4호
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• pp.219-227
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• 2019

본 연구는 심리적 과정에 따른 운동행동의 변화를 알아보기 위해 운동변화단계와 운동자기도식, 운동중단유혹의 관계를 분석하는데 목적이 있다. 연구목적 달성을 위하여 공공스포츠센터를 이용하는 성인을 대상으로 총 297부의 최종자료를 사용하였다. 자료처리는 SPSS 18.0을 이용하여 탐색적 요인분석 후 다변량분석, 중다회귀분석, 판별분석을 통해 검증하였다. 연구결과는 첫째, 운동변화단계에 따라서 운동자기도식은 차이가 있는 것으로 나타났다. 둘째, 운동변화단계에 따라서 운동중단유혹은 지도자와 의욕상실에서 차이가 있는 것으로 나타났다. 셋째, 행동적 자기도식과 의욕상실은 운동변화단계를 판별하는데 주요 요인인 것으로 나타났다. 넷째, 운동자기도식은 의욕상실에 부적 영향을 미치는 것으로 나타났고, 감정에는 인지-감정적 자기도식이 부적 영향을 미치는 것으로 나타났다.

• 대한간호학회지
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• 제35권8호
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• pp.1443-1450
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• 2005

Purpose. The study was conducted to identify predictors of mammography screening for rural Korean women according to 'Stage of Change' from the Transtheoretical Model which, along with the Health Belief Model, formed the theoretical basis for this study. Methods. A cross-sectional descriptive design was utilized. Through convenience sampling 432 women were selected from 2 rural areas. Data were collected by survey. Health beliefs constructs were measured with Champion's HBM Scale-Korea version. Mammography participation was measured using the Stage of Mammography Adoption Scale developed. by Rakowski, et al.(1992). Results. The most frequent stage of mammography adoption was 'contemplation' ($40.5\%$). Predictors of stage of mammography adoption included 'mammogram recommended by health professional' (beta==0.59, t=16.12, p=.000), 'perceived benefits' (beta=0.09, t=2.21, p=.050), 'perceived susceptibility' (beta=0.09, t=1.98, p=.050), and 'perceived barriers' (beta=-0.07, t=-2.05, p=.041). 'Mammogram recommended by health professional' demonstrated the greatest association with having a mammogram. Conclusion. Health professionals play key roles in improving mammography participation and should recognize the importance of their role in cancer prevention and be more actively involved in education and counseling on prevention of breast cancer.

• 조명전기설비학회논문지
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• 제29권3호
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• pp.81-87
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• 2015

In order to effectively protect electrical and electronic circuits which are extremely susceptible to lightning surges, multi-stage surge protection circuits are required. This paper presents the operational characteristics of the two-stage hybrid surge protection circuit in extra-low voltage DC power lines. The hybrid surge protective device consists of the gas discharge tube, transient voltage suppressor, and series inductor. The response characteristics of the proposed hybrid surge protective device to combination waves were investigated. As a result, the proposed two-stage surge protective device to combination wave provides the tight clamping level of less than 50V. The firing of the gas discharge tube to lightning surges depends on the de-coupling inductance and the rate-of-change of the current flowing through the transient voltage suppressor. The coordination between the upstream and downstream components of the hybrid surge protective device was satisfactorily achieved. The inductance of a de-coupler in surge protective circuits for low-voltage DC power lines, relative to a resistance, is sufficiently effective. The voltage drop and power loss due to the proposed surge protective device are ignored during normal operation of the systems.

• 한국유체기계학회 논문집
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• 제7권3호
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• pp.14-22
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• 2004

Bileaflet mechanical valves have the complications such as hemolysis and thromboembolism, leaflet damage, and leaflet break. These complications are related with the fluid velocity and shear stress characteristics of mechanical heart valves. The first aim of the current study is to introduce fluid-structure interaction method for calculation of unsteady and three-dimensional blood flow through bileaflet valve and leaflet behavior interacted with its flow, and to overcome the shortness of the previous studies, where the leaflet motion has been ignored or simplified, by using FSI method. A finite volume computational fluid dynamics code and a finite element structure dynamics code have been used concurrently to solve the flow and structure equations, respectively, to investigate the interaction between the blood flow and leaflet. As a result, it is observed that the leaflet is closing very slowly at the first stage of processing but it goes too fast at the last stage. And the results noted that the low pressure is formed behind leaflet to make the cavitation because of closing velocity three times faster than opening velocity. Also it is observed some fluttering phenomenon when the leaflet is completely opened. And the rebounce phenomenon due to the sudden pressure change of before and after the leaflet just before closing completely. The some of time-delay is presented between the inversion point of ventricle and aorta pressure and closing point of leaflet. The shear stress is bigger and the time of exposure is longer when the flow rate is maximum. So it is concluded that the distribution of shear stress at complete opening stage has big effect on the blood damage, and that the low-pressure region appeared behind leaflet at complete closing stage has also effect on the blood damage.

• 시큐리티연구
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• 제21호
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• pp.95-120
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• 2009

본 연구는 카지노 시큐리티 종사자의 운동변화단계에 따른 신체적 자기개념과 자기효능감의 관계를 규명하는데 목적이 있다. 연구의 목적 달성을 위하여 전국 카지노 17개업체중 시큐리티 관련업무 30명 이상을 고용하고 있는 8개의 업체를 모집단으로 설정하여 표본을 추출하였다. 이 연구에서 시큐리티 종사자 30명 이상을 고용하고 있는 업체를 선정한 이유는 30명 이하의 영세한 업체에서 조직구성 및 직무체계와 환경이 대체적으로 차이가 있으므로 이에 따른 연구결과를 일반화하기에는 다소 제한적이라고 판단되기 때문이다. 편의 추출법(convenience sampling)에 의하여 대상을 표집 하였으며, 선정된 연구대상자는 본 연구의 취지 및 설문조사 교육을 받은 조사원을 통해 운동변화단계에 따른 신체적 자기개념과 자기효능감의 관계 설문지를 자기평가 기입법(self-administration method)에 따라 설문조사를 실시하였다. 연구 조사 자료의 결과를 처리하기 위하여 Window SPSS 16.0프로그램을 이용하여 분석하였으며, 측정도구의 타당성을 검증하기 위해 탐색적 요인분석(factor analysis)과 신뢰도 검증을 위하여 하위 척도별 내적 일관성 계수(Cronbach's alpha)를 산출하였다. 주성분 분석(principle component factor analysis)을 이용하였으며. 요인회전방법으로 직각회전방식(varimax rotation)을 이용하였다. 초기 고유값(Eigen value) 1.0을 요인 추출의 준거로 삼았다. 운동변화단계에 있어 성별, 근무형태의 차이를 알아보기 위하여 운동 변화단계에 대한 차이를 검증하기 위해 $X^2$을 실시하였다. 운동변화단계에 따라 신체적 자기개념과 자기효능감의 차이를 알아보기 위하여 운동변화단계를 독립변수로 신체적 자기개념과 자기효능감을 종속변수로 하는 일원변량분석(one-way ANOVA)을 실시하였다. 집단간의 평균차를 검증하기 위하여 사후검증으로 Scheffe 검증을 실시하였다. 신체적 자기개념이 자기효능감에 미치는 영향을 알아보기 위하여 먼저 상관관계분석을 실시하였고, 신체적 자기개념을 독립변수로 하고 자기효능감을 종속변수로 하는 다중회귀분석(multipie regression analysis)을 실시하였으며, Enter 방식으로 처리하였다. 이와 같은 방법과 절차에 따른 자료 분석을 통하여 얻은 결론은 다음과 같다. 첫째, 카지노 시큐리티 종사자들의 운동행동변화단계는 성별과 근무형태에 따라 운동행동 변화단계에 차이가 있었다. 둘째, 운동행동변화단계에서 유지단계로 이행 할수록 신체적 자기 개념과 자기효능감을 지각하는 정도가 높게 나타났다. 셋째, 신체적 자기개념의 하위요인 중, 신체활동과 체지방에 대한 정도가 자기효능감에 유의한 영향을 미쳤다.

• 성인간호학회지
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• 제16권3호
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• pp.421-431
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• 2004

Purpose: The study was performed to investigate the predictors associated transition with each stage of exercise behavior based to the Transtheoretical Model, and to provide basic data for exercise behavior programs for middle aged women. Methods: The subjects consisted of 434 women residing in B city by convenience sampling. The collected data were analyzed with multiple logistic regression using SPSS/WIN program. Results: The predictors of transition from precontemplation to contemplation were consciousness raising(OR=2.095, 95% CI: 1.305-3.363), Reinforcement management(OR= 1.903, 95% CI: 1.107-3.271), Stimulus control (OR=2.176, 95% CI:1.239-3.820), Menstrual status (OR=5.327, 95% CI: 1.110-25.562). The predictors of transition from contemplation to preparation were Helping relationship(OR= 1.671, 95% CI: 1.065-2.662), Pros(OR=2.500, 95% CI: 1.254-4.982), Perceived Health status (OR=.178, 95% CI: .041-.770). The predictor of transition from preparation to action was Stimulus control(OR=1.918, 95% CI: 1.103- 3.336). The predictors of transition from action to maintenance were Consciousness raising(OR= 1.939, 95% CI: 1.031-3.647), Dramatic relief (OR=2.249, 95% CI: 1.025-4.931). Conclusions: Adequate examination on the factors, which can predict the transitional stages of change exercise behaviors among middle aged women, which is presented in this study. The results of this study will become the pillar of exercise intervention program planning and application.

• 한국공간구조학회논문집
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• 제22권1호
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• pp.17-24
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• 2022

Currently, the construction trend of high-rise structures is changing from a cube-shaped box to a free-form. In the case of free-form structures, it is difficult to predict the behavior of the structure because it induces torsional deformation due to inclined columns and the eccentricity of the structure by the horizontal load. For this reason, it is essential to review the stability by considering the design variables at the design stage. In this paper, the position of the weak vertical member was analyzed by analyzing the behavior of the structure according to the change in the core position of the twisted high-rise structures. In the case of the shear wall, the shear force was found to be high in the order of proximity to the center of gravity of each floor of the structure. In the case of the column, the component force was generated by the axial force of the outermost beam, so the bending moment was concentrated on the inner column with no inclination.

• 보건교육건강증진학회지
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• 제24권4호
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• pp.115-130
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• 2007

Purpose: The Purpose of this study was to investigate the effects of the '5&6 smoking cessation program - six classes in five weeks' on the high school students' perception and smoking behavior. Methods: The data collection was done from November to December, 2006. This study was designed using nonequivalent control group pretest - posttest. Experimental group had 24 students, control group had 41 students. The '5&6 smoking cessation program' was applied to the experimental group for two hours per session during five weeks. Data analysis was done using descriptive statistics, X2-test, Fisher's exact test, Independent-samples t-test, Paired t-test, Cronbach's coefficient alpha. Results: The experimental group showed significant increase on smoking self-efficacy, stage of smoking cessation behavior change and significant decrease on daily smoking amount, dependancy of nicotine, urine cotinine level than control group. But the experimental group was not significantly changed at self-awareness, Pros. for smoking and Cons. for smoking. Conclusion: In conclusion, the results of this study showed that the 5&6 smoking cessation program, which focuses on self-awareness, is effective in adolescent's smoking cessation behaviors.

• 한국공작기계학회논문집
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• 제13권1호
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• pp.88-93
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• 2004

In general, a fundamental structural design consideration for an automobile is the overall dynamic behavior in bending and torsion. Dynamic behavior of the automobile are mainly influenced by the structural stiffness of B.I.W.(body-in-white) and the physical property of trim components. In this paper, the modeling techniques for various trim components of middle-sized bus are presented, and the dynamic effects of the trim components on the vibration characteristics of the bus are investigated. The $1^{st}$ torsional frequency is decreased by attaching windshield and backlite to the B.I.W., but the $1^{st}$ vertical bending frequency and the $1^{st}$ lateral bending frequency are increased. The natural frequencies of the bus are decreased by attaching doors and windows. And also, the natural frequencies of the bus are large decreased by attaching seats, instrument panel etc. The study shows that the dynamic characteristics of the bus can be effectively predicted in the initial design stage.