• 한국항공우주학회지
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• 제31권8호
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• pp.99-106
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• 2003

본 논문에서는 액체추진로켓용 터보펌프내 초음속 충동형 터빈의 공력성능 향상을 위해 기하학적 설계변수를 수치적으로 연구하였다. 터빈의 기하학적 설계변수는 아랫면, 윗면 원호반경, 입사각, 익단두께로 설정, 적절한 구속조건을 도입하였고 목적함수로는 최대파워를 채택하였다. 목적함수를 얻기 위해 2-D Navier-Stokes 방정식과 Chien의 k-$\varepsilon$ 난류 모델링을 수치적으로 계산하였다. 초기모델에서 이형 중앙부에 흐름박리를 볼 수 있었으나 개선된 익형에서 흐름박리는 제거되었다. 본 연구를 통해 약 3.2 %의 축 파워가 증대되었다.

• 산업공학
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• 제10권1호
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• pp.169-187
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• 1997

Recently, in organizations many decisions are being made by groups. And the organization is changing a lot so are groups. To help decision making of changing groups, we need more flexible and more adaptive GDSS. Therefore one of the critical success factors of GDSS is flexibility and incremental improvement. Prior research on specifying design requirements of GDSS suggests generic design requirements. But they are too general to be incorporated directly into system design, because of the disparity between real group and ideal group that the researchers studied. Many design strategies that start from the generic design requirements thus have contingency variables that changes as the characteristics of group change. From the viewpoint of developers, these variables implicate the desirability of flexibility. To achieve flexibility we need new methodology of design and implementation. Nowadays, object-oriented analysis and design methodologies have been progressed to the point that many systems are being developed through these methodologies. In this paper, a design is proposed using Object-Oriented Modeling Techniques(OMT). Exploiting object-oriented paradigm results in a highly flexible and easily upgradable design.

• 한국실내디자인학회논문집
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• 제24권4호
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• pp.99-110
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• 2015

The purpose of this study is to identify pre-elderly's housing mobility related characteristics (reasons for moving, change of personal life after move, housing attachment, and plan to future move) and to examine the associations between their socio-demographic characteristics and housing characteristics, and their housing mobility related characteristics. A total of 200 usable data were collected through personal survey using a questionnaire developed by the researcher. Samples were selected in Seoul and new towns in the capital area and a survey conducted from February, 2014 to December, 2014. For the analyses, descriptive statistics, factor analysis, t-test and ANOVA were used. The most frequently mentioned reasons for moving were 'a good place for nature and retirement life'. Age, education level, liiving expenses, locaion, tenure status, and housing size were the variables to show significant difference to reasons for moving. Respondents experienced positive personal life changes after moving, especially, 'physical health' and outgoing activity'. Respondents who moved to a new town was more positively changed. Personal life changes was the most important variable associated with 3 factors of housing attachment. Location, tenure status, housing size were the major variables to show differences to housing attaachment. Also, personal life changes after moving and housing attachment were the important variables affecting a plan to future move. In other words, the respondents who do not plan to future move showed higher positive life change and strong housing attachment.

• 한국ITS학회 논문지
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• 제17권1호
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• pp.1-16
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• 2018

생활패턴의 변화는 통행의 목적을 변화시키기 때문에 궁극적으로 통행패턴의 변화를 야기한다. 이에 따라 본 연구에서는 1999년부터 2014년까지 통계청에서 조사한 생활시간조사자료를 활용하여 연도별 통행시간에 영향을 미치는 요인을 분석하고자 한다. 가구관련, 개인관련, 시간관련 변수들을 고려한 통행시간에 관한 다중선형회귀모형을 구축하였으며, 요일별 차이를 보기위해 주중과 주말을 분리하여 추정하였다. 모형 추정 결과, 가구관련, 개인관련, 시간관련 변수가 통행시간에 영향을 미치는 것으로 분석되었다. 가구관련변수의 경우 개인관련변수에 비해 비교적 적은 변수들이 유의한 것으로 나타났는데, 이는 통행이 개인특성에 더 큰 영향을 받기 때문인 것으로 판단된다. 각 활동시간들은 통행시간에 양의 영향을 미치는 것으로 분석되어 통행이 파생수요임을 나타내고 있다. 또한 여가활동시간이 가장 큰 영향력이 있는 것으로 도출되어, 여가를 위한 통행시간이 타활동에 비해 증가하는 것으로 분석되었다.

• 간호행정학회지
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• 제3권2호
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• pp.109-122
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• 1997

This Study was dosigned to test the relationship between effectiveness of nursing organization and related variables of organization on the perspectives of total quality management, The data were collected through self reported questionnaires from 138 nurses working in, 288 patients hospitalized in one tertiary hospital in Seoul from May 30 to October 10 in 1996. The data were analyzed by using the pc-SAS program. The information was obtained of descriptive statistics, correlation analysis, multiple regression, ANOVA & Tukey's multiple comparison test. Results showed that the managing change, the managing job design, the managing conflict, the formation and the centralization of nursing organization structure were shown to be relating variables for nurses' job satisfaction. Especially the managing change was the predictor of nurses' job satisfaction, It explained 57% of total variance. According to clustor analyses of the variables of the managing change, the managing job design, the managing conflict, the nursing units were divided three clusters and according to ANOVA, there was significint difference in nurses' job satisfaction The nurses' job satisfaction was higher in the nursing units revealed to have high job management score. But there was no significant difference in patient satisfaction among three clusters.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.548-551
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• 2004

Magnetostrictive actuators have seen increasing use in fine positioning system because it has many advantages such as friction free, resolution of ${\mu}{\textrm}{m}$ or nm scale, and powerful output force. Usually, the magnetic circuit of magnetostrictive actuator has components which are flux return path, coil, and magnetostrictive material. It is classified in two types according to existence of the permanent magnet. The magnetic circuit having optimal performances transfer magnetic field which is obtained by providing input current at coil without energy loss. This paper described mathematical model of magnetic circuit for getting design variables. The modeling equation is obtained from the relations between flux and reluctance of the magnetic equivalent circuit. Also, finite element analysis has been used to study the performance of magnetic circuit according to change of design variables such as existence and shape of the permanent magnet, flux return path etc. The modification of dimensions enables us to optimize magnetic circuit.

• Structural Engineering and Mechanics
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• 제4권4호
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• pp.425-436
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• 1996

An application of the perturbation method to optimum structural design with random parameters is presented. It is formulated on the basis of the first-order stochastic finite element perturbation method. It also takes into full account the stress, displacement and eigenvalue constraints, together with the rates of change of the random variables. A method for calculating the sensitivity coefficients in regard to the governing equation and the first-order perturbed equation has been derived, by using a direct differentiation approach. A gradient-based nonlinear programming technique is used to solve the problem. The numerical results are specifically noted, where the stiffness parameter and external load are treated as random variables.

• 대한간호학회지
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• 제23권4호
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• pp.694-712
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• 1993

A number of nursing researchers have used the concept of health locus of control over the past decade in Korea. This article reviewed 92 nursing research papers on health locus of control conducted since 1982, and examined type of subjects, design, measurement instruments, the scores of each dimension of the HLOC, and significant variables. Most of the research were correlational in design, used an 18-item 6-point score instrument and studied the relationship between HLOC, health re-lated variables, and cognitive-emotional variables, The health related variables included health behavior, health management, preventive health behavior, compliance to treatment regimen and self care behavior The cognitive-emotional variables included depression, anxiety, stress and self- esteem. Some consistent findings are beginning to emerge. The concept of internal HLOC was positively correlated with the health related variables. But few studies found any significant correlation between powerful others HLOC and health related variables. In the case of chance HLOC, few studies reported a significant relationship. Many of the articles reported significant relationships between internal HLOC and cognitive-emotional variables, but few reported a significant relationship between powerful others or chance HLOC and cognitive -emotional variables. all experimental studies but one found that only internal HLOC was significantly changed following experimental manipulation. When the different groups of subjects such as normal persons, chronic patients, acute patients were compared in terms of mean scores, it was found that the HLOC appeared to change depending on the status of the patients. Recommendations for future research include modification of the instrument to increase the reliability and validity, study about the pattern of response suggested by Wallston and Wallston(1982) and further experimental study on changing the belief of subjects to internal HLOC.

• 대한기계학회논문집
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• 제15권6호
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• pp.1852-1860
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• 1991

본 연구에서는 연구대상을 주어진 구조물 형상에서 경계조건의 변화에 따른 현상 설계민감도, 특히 하중경계조건의 변화에 따른 구조물의 변형에 주안점을 두었다. 이 연구결과는 가공물의 지지위치에 따른 가공면의 변형정도 향상 및 접촉문제 해석등 에 응용이 가능하다. 유도된 민감도가 정확함을 입증하기 위하여 예제로서 하중경계 조건의 변화에 따른 범함수로 정의된 변형의 변화량을 예측하는 문제를 선정하였다.

• 한국환경교육학회지:환경교육
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• 제10권2호
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• pp.213-228
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• 1997

This study was planned to test the educational effects of self-guiding environmental interpretation panel. For purpose of the study, self-guiding interpretation panel was set up along the trail of green shower area of Kwang-Reung Arboretum in 1995,and the environmental behavior related variables such as attitude, locus of control, personal responsibility, general knowledge, and intention to act were closen based on Hines and his colleagues' Responsible Environmental Behavior model(1987). The pre-test/post-test non-random control group design was introduced fo test the effects of panel. ANCOVA was used to test the differences between experimental and control group because of the need to consider the effects of other variable such as socio-economic variables on the changes of environmental behavior related variables. Among 5 environmental behavior related variables, the changes of attitude and knowledge were significantly different between experimental group and control group, and the experimental group's direction of change was more favorable for environment. It is concluded that the educational effects of self-guiding interpretation panel were partially accepted. Several recommendations and restrictions of the study are presented.