• 대한간호학회지
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• 제31권2호
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• pp.221-231
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• 2001

This study was conducted by analyzing all 33 articles based on the LISREL, published from January 1991 to March 1999 in Korea. The analyses consisted of the publication date of articles, principal dependent variables, subjects of the research, adequacy of sampling, adequacy of research purposes and results, accordance between theoretical model and hypothetical model, fit measures, theoretical base of model modification, and adequacy of conclusion. The results were as follows : . The thesis of 33 articles in total were outnumbered as 25 (75.8%) to 8 (24.2%) research articles. As for a sex classification of the subjects, 45.5% of the research were conducted around a female group of subjects, while 54.5% were done for both sex, The range of the sample size was 105 to 803, and the average was 259 subjects. . A single theoretical variable was measured for each measurement variable, any difference between variables was hardly found in 8 articles (24.2%), and 19 articles (57.6%) did not consider any measurement error. To analyze if the representative has been articles (21.2%) were seen with a sign of a representative. Questionnaires were used in a majority (31 articles) of the data collecting process. Only 2 articles (6.1%) were measured with a physiologic index simultaneously. . 14 articles (42.2%) were centered on theory development, 10 articles on theory synthesis, and 9 articles on theory test. The research purposes and results were consistent in 25 articles (75.5%) and 8 articles (24.2%) were inconsistent. The quality of life and health promotion behavior were the concepts most frequently studied as a dependent variable, and 7 articles centered on them. In applied theories a health promotion model was used on 4 articles (12.1%), while role theory and stress-coping models were in 3 articles respectively. . The articles were analyzed to see if the hypothetical model was elaborated and tested by the theoretical model. Twenty-five articles proved to be rationale for the inconsistencies. Also, 56.5% proposed hypotheses were supported among the subject articles, and 30 articles (90.0%) suggested a revised model. Path coefficient (17 articles) and theoretical adequacy (17 articles) were the standards mostly used. In conclusion, the principal factors were obtained from the research are to be considered as the principes of LISREL application. First, a model has to be established on a theoretical base rather than empirical results dependent on the data. The results are also required to be globally interpreted. Secondly, at least 200 samples are necessary to satisfy the need. Third, more than 3 measurement variables are to be adjusted to a single theoretical variable; the measurement errors must be suggested as well. Finally, normal distribution characteristics of the data and the estimation method need to be reported. Based on the research result, the follows are suggested; . Systematic criteria on the LISREL application and procedure need to be developed . Agreement form is required to report the results of research using the LISREL

• 디지털융복합연구
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• 제18권8호
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• pp.11-19
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• 2020

최근 몇 년 사이 대학생들이 중국 혁신과 창업의 주역으로 부상하고 있다. 본 논문은 TPB 이론을 바탕으로 창업 교육 변수를 도입하고 대학생을 대상으로 한 창업 교육이 창업 의욕에 미치는 영향 모델을 구축하였다. 본 논문에서는 행동 태도, 주관적 규범, 인지적 행동조절, 기업가정신 교육 및 기업가적 의도 등 5가지 변수가 포함된 설문을 활용하여 중국 길림성에 소재한 6개 대학의 학생들을 대상으로 조사하였고 SPSS23.0을 사용하여 통계분석을 수행하였다. 연구 결과 계획된 행동 이론의 세 가지 요소인 행동 태도, 주관적 규범, 인지적 행동조절과 비교했을 때 대학생들의 기업가정신 교육이 기업가적 의도에 가장 큰 영향을 미친다는 것을 확인하였다. 본 논문은 대학에서 창업 교육을 강화하는 데 선도적 의의가 있다. 본 연구는 길림성 소재 6개 대학 학생들만을 대상으로 한 것으로 연구결과를 일반화하기위해서는 향후 중국 전역으로 연구범위를 확장할 필요가 있다.

• 한국가스학회지
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• 제15권6호
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• pp.34-37
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• 2011

본 논문에서는 배관을 연결하기 위해 사용한 탄성접촉시일의 밀봉접촉응력과 변형거동 특성을 다루고 있다. 본 연구에서 배관을 연결하기 위해 체결너트와 탄성접촉시일 사이에 가해진 밀봉압축 간섭량은 0.2~0.5mm이다. 탄성접촉시일을 압축하기 위한 밀봉 간섭량은 두 개의 배관을 하나의 너트로 체결하는 과정에 발생한다. FEM 해석결과에 의하면, 경사진 밀봉표면을 갖는 접촉모델 1의 접촉수직응력은 평행한 밀봉표면을 갖는 접촉모델 2의 접촉수직응력에 비해 1.5~1.75배나 높게 나타났다. 이것은 배관과 배관을 연결하는 밀봉접촉표면이 높은 밀봉압축응력을 얻을 수 있도록 하기 위해 쇄기형상의 접촉모드를 형성하는 것이 바람직함을 알 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.680-689
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• 2011

A dynamic analysis procedure is developed to provide a comprehensive estimation of the dynamic response spectrum for locomotive's wheels running over a Pre-Stressed Concrete (PSC) box girder bridge on the Korea high speed railway. The wheel force spectrum with the bridge behavior are analyzed as the dynamic procedure for various running speeds (50~450km/h). The high-speed railway locomotive (KTX) is used as 38-degree of freedom system. Three displacements(vertical, lateral, and longitudinal) and three rotational components (pitching, rolling, and yawing). For one car-body and two bogies as well as five movements except pitching rotation components for four wheel axes forces are considered in the 38-degree of freedom model. Three dimensional frame element is used to model of the PSC box girder bridges, simply supported span length of 40m. The irregulation of rail-way is derived using the exponential spectrum density function under assumption of twelve level tracks conditions based on the normal probability procedure. The dynamic responses of bridge passing through the railway locomotive with high-speed analyzed by Newmark-${\beta}$ method and Runge-Kutta method are compared and contrasted considering the developed models of bridge, track and locomotive comprehensively. The dynamic analyses of wheel forces by Runge-Kutta method which are able to analyze the forces with high frequency running on the bridge and ground rail-way are conducted. Additionally, wheel forces spectrum and three rotational components of vehicle body for three typical running speeds is also presented.

• Tribology and Lubricants
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• 제33권3호
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• pp.98-105
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• 2017

A pin-on-disk test is performed to measure the wear volume of a ductile cast iron (DCI) roll when it wears down using a high carbon steel and two alloy steels at different sliding velocities between the roll and the material (steel). Normal pressure is set as constant and test temperatures are 400, 500 and $600^{\circ}C$. In addition, thermal softening behavior of the DCI roll is examined using a high-temperature micro-hardness tester and the surface hardness variation of the DCI roll is expressed in terms of temperature and heating time. Based on experimental data, a wear coefficient used in Archard's wear model for each material is obtained. The wear volume is clearly observed when the test temperature is $400^{\circ}C$ and sliding velocity varies. However, it is not measured at temperatures of $500^{\circ}C$ and $600^{\circ}C$ even with variations in sliding velocity. From the optical photographs of the pin and disk, the abrasive wear is observed at $400^{\circ}C$ clearly, but no at $500^{\circ}C$ and $600^{\circ}C$. At higher temperatures, the pin surface is not smooth and has many tiny caves distributed on it. It is found that wear volume is dependent on the carbon contents rather than alloy contents. Results also reveal that the variations of wear coefficients are almost linearly proportional to the carbon contents of the material.

• 동의신경정신과학회지
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• 제14권1호
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• pp.1-16
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• 2003

Objective : This study was designed to assess the protective effects of Hwangryeonhaedoktang on the animal model of depression, induced by chronic mild stress(CMS). Method : Male Sprague-Dawley rats were used for this experiment. The subjects were divided into 3 groups ( 1. CMS-drug: Hwangryeonhaedoktang administered during CMS treatment, 2. CMS-vehicle: water administered, 3. normal ). After 4 weeks of CMS treatment, they were executed forced swimming test(FST), open field test and c-Fos in paraventricular nucleus(PVN) were measured. Result : 1. In FST, immobility behavior decreased significantly in CMS-drug group. 2. There was no difference in the open field test between 3 groups 3. c-Fos expressed cell bodies in PVN were significantly less in CMS-drug than in CMS-vehicle group. Conclusion : These results suggest that Hwangryeonhaedoktang may have protective antidepressant effects in CMS model rats. And these effects could be explained by the elevated stress-copying behaviors which are related with PVN of hypothalamus.

• 지역사회간호학회지
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• 제13권2호
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• pp.260-271
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• 2002

Objectives: The purpose of this study was to identify basic health needs of adult clients to develop a community nursing center model in Seoul. Methods: Data were collected using a questionnaire survey from 894 adults registered at a public health center who were health management members, and visiting 4 community nursing centers, University of Wisconsin, Milwaukee during the period from July 1999 to January 2000. The data were analyzed using frequency, percentile, t-test, and ANOVA. Results: 1) The University of Wisconsin- Milwaukee School of Nursing has a long tradition of developing 4 community nursing centers with innovative health care programs. CNCs integrate the ability to implement and test effective intervention strategies with education, research, and practices of nursing students and faculty. They were designed to enhance the health status and quality of life for urban communities through the development of productive, outcome focused, collaborative partnerships among UWM-Nursing faculties and staff, other health and human service providers, consumers, and policy makers. It links the financial resources between UWM and 9 voluntary agencies and 12 public funding organizations including federal. state, and local governments. 2) Of the total health management members, 37.4% were reported to have at least one type of chronic disease such as hypertension, diabetes, and arthritis. Ten percent of them reported having obesity, and 44.2% reported lack of exercise. The health status of the subjects was within normal range in laboratory tests. However, female subjects showed more significant differences in obesity and cholesterol levels than male subjects. The subjects, who were in their 50s, showed more significant differences in obesity, SGOT, SGPT, and cholesterol levels than the subjects in other age groups. Conclusion: A community nursing center needs to be developed, that has a link between the nursing college and the public health center, with partnerships and a multidisciplinary approach. Based on the study results, exercise programs for middle aged adults are considered necessary. In particular, specific exercise programs for pre-menopausal women needs to be implemented in the future to prevent them from developing osteoporosis.

• Structural Engineering and Mechanics
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• 제65권3호
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• pp.291-302
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• 2018

Rigid body spring method (RBSM) is an effective tool to simulate the cracking process of structures, and has been successfully applied to investigate the behavior of reinforced concrete (RC) members. However, the theoretical researches and engineering applications of this method mainly focus on two-dimensional problems as yet, which greatly limits its applications in actual engineering projects. In this study, a three-dimensional (3-D) RBSM for RC structures is proposed. In the proposed model, concrete, reinforcing steels, and their interfaces are represented as discrete entities. Concrete is partitioned into a collection of rigid blocks and a uniform distribution of normal and tangential springs is defined along their boundaries to reflect its material properties. Reinforcement is modeled as a series of bar elements which can be freely positioned in the structural domain and irrespective of the mesh geometry of concrete. The bond-slip characteristics between reinforcing steel and concrete are also considered by introducing special linkage elements. The applicability and effectiveness of the proposed method is firstly confirmed by an elastic T-shape beam, and then it is applied to analyze the failure processes of a Z-type component under direct shear loading and a RC beam under two-point loading.

• 콘크리트학회지
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• 제5권4호
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• pp.179-187
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• 1993

본 연구에서는 콘크리트의 강도수준에 따른 피로실험을 수행하여 고강도 콘크리트의 피로거동 특성을 분석하였다. 실험변수는 4종류의 강도수준(26 MPa, 54 MPa, 82 MPa, 103 MPa)과 4종류의 최고 응력수준(75%, 80%, 85%, 95%)이며 실험에 사용된 공시체는 ${\phi}100{\times}200mm$의 원통형 공시체로서 총 160개가 제작되었다. 실험결과, 강도수준이 증가함에 따라 피로강도가 감소하였고 강도수준의 영향을 고려한 S-N-f'c 관계식을 제안하였다. 또한 강도수준의 영향 이외에도 변형도율 효과를 도입하여 피로실험과 압축실험에서 발생하는 하중재하율의 차이를 보정하였다. 한편, 피로 비탄성변형도는 강도수준이 증가함에 따라 감소하였으나 반복횟수에 따른 변형도 증가율은 강도수준이 높을수록 큰 것으로 나타났다.

• Computers and Concrete
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• 제2권1호
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• pp.79-96
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• 2005

The use of high-strength concrete (HSC) has significantly increased over the last decade, especially in offshore structures, long-span bridges, and tall buildings. The behavior of such concrete is noticeably different from that of normal-strength concrete (NSC) due to its different microstructure and mode of failure. In particular, the shear capacity of structural members made of HSC is a concern and must be carefully evaluated. The shear fracture surface in HSC members is usually trans-granular (propagates across coarse aggregates) and is therefore smoother than that in NSC members, which reduces the effect of shear transfer mechanisms through aggregate interlock across cracks, thus reducing the ultimate shear strength. Current code provisions for shear design are mainly based on experimental results obtained on NSC members having compressive strength of up to 50MPa. The validity of such methods to calculate the shear strength of HSC members is still questionable. In this study, a new approach based on artificial neural networks (ANNs) was used to predict the shear capacity of NSC and HSC beams without shear reinforcement. Shear capacities predicted by the ANN model were compared to those of five other methods commonly used in shear investigations: the ACI method, the CSA simplified method, Response 2000, Eurocode-2, and Zsutty's method. A sensitivity analysis was conducted to evaluate the ability of ANNs to capture the effect of main shear design parameters (concrete compressive strength, amount of longitudinal reinforcement, beam size, and shear span to depth ratio) on the shear capacity of reinforced NSC and HSC beams. It was found that the ANN model outperformed all other considered methods, providing more accurate results of shear capacity, and better capturing the effect of basic shear design parameters. Therefore, it offers an efficient alternative to evaluate the shear capacity of NSC and HSC members without stirrups.