• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.379-386
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• 2004

The optimal seismic retrofitting of NPP(Nuclear Power Plant) cabinet structures that contained class 1 relays were studies in this paper. During earthquake event, the failure modes of relays are not appeared in form of structural failure, but are appeared in form of contact chatter of relay. Therefore, the retrofitting of cabinet has to be aimed to the reducing of the structural response, such as acceleration. In this study, the optimal characteristic values of dampers were searched by μ-GA (micro-Genetic Algorithm) scheme for several installation patterns. To keep accuracy and efficiency of analysis, the structural models of cabinet were considered as a frame structure. The responses of structure were obtained in form of acceleration response spectra derived from the results of nonlinear time history analysis including damping nonlinearity. The fitness function of the optimum procedure was constructed based on the ratio of maximum spectral value and target GERS (General Equipment Ruggedness Spectra). The results show the good improvements of fitness fur adequate retrofitting pattern. Especially, the improvements of fitness were remarkable when the damping exponents are proper.

• 한국IT서비스학회지
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• 제6권1호
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• pp.47-63
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• 2007

A lot of researchers have been interested in the factors influencing the use of mobile phone services. Most of the previous studies, however, verified only the research models developed by the authors. They did not consider which model agrees better with the real situation. This study presents six alternative models based on various previous studies, and compares the data fitness of the models. A Web survey of mobile phone users collected 2,217 cases. Statistical analyses, using SEM (Structural Equation Modeling), show that the fitness of the simplest alternative model is better than that of any other model. The simplest model has no causal relationship among exogenous factors, and proposes that all of exogenous factors have direct impacts on the customer satisfaction. In addition, the analyses say that corporate and brand image and additional service are more important than the other exogenous factors such as communication quality.

• 대한가정학회지
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• 제40권9호
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• pp.175-189
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• 2002

The purpose of this study was to test a structural model about family income as causally related to family hardiness, pile-up stress, communication, and family adaptation in families of children with disabilities. 250 families of children with disabilities participated as subjects. The models were developed on the basis of confirmatory factor analysis and compared using covariance structure modeling(LISREL). Adequate fitness of the model was observed. Family income showed negative effect on pile-up stress and positive effect on family adaptation. Pile-up stress showed negative effect on family hardiness. Family hardiness showed positive effect on family communication, and family communication showed positive effect on family adaptation.

• 산업융합연구
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• 제20권2호
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• pp.21-27
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• 2022

본 연구목적은 일반고 학생들의 자기주도 학습, 온라인 수업 환경, 그리고 학습만족도 간의 구조관계를 탐색하는 것이다. 연구 대상은 세종 B고교 3학년의 219명이며, 상관관계와 구조방정식 모형을 분석했다. 연구결과는 다음과 같다, 첫째, 자기주도 학습과 온라인 수업 환경 및 학습만족도 간에는 중간 이상의 상관관계를 있었다. 둘째로, 측정변인들 간의 구조모형의 적합도 지수도 양호했다. 자기주도 학습은 온라인 수업 환경에 영향을 주고, 온라인 수업환경은 학습만족도에 정적으로 영향을 주지만, 자기주도 학습은 학습만족도에 유의한 영향력은 없었다. 본 연구의 시사점은 학습자의 온라인 수업만족도는 학생의 자기주도 학습능력이 교사의 훌륭한 수업환경의 조성이 이루어질 때 시너지 효과를 얻음을 알 수 있다. 추후 온라인 학습만족도에 대하여 다양한 학습자의 개인, 가정 및 학교요소를 종합적으로 투입하는 분석할 것을 제안했다.

• 한국지진공학회논문집
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• 제9권1호통권41호
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• pp.1-7
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• 2005

본 논문에서는 원전내부의 내진범주 1급 계전기를 포함하고 있는 캐비닛 구조물의 최적내진보강에 대한 연구를 수행하였다. 지진시 계전기는 구조적인 파괴보다는 떨림에 의한 기능적 파괴가 발생한다. 이를 방지하기 위해서는 캐비닛구조물의 응답을 적정 수준이하로 감소시켜야 하므로 다양한 감쇠보강의 설치패턴에 따라 최적의 감쇠계수를 ${\mu}$-GA(micro-Genetic Algorithm)기법을 이용하여 산정하였다. 대상캐비닛 구조물은 해석의 정확도와 계산의 효율성을 만족시키기 위해 이용한 프레임구조로 모델링되었다. 구조물의 응답은 감쇠기의 비선형거동을 고려한 비선형 시간이력해석에 의해 얻어진 가속도응답스펙트럼으로 나타내었다. 목적함수는 구조물의 해석에서 얻어진 응답스펙트럼의 최대값과 목표 포괄기기내진력 스펙트럼 (GERS; General Equipment Ruggedness Spectra)의 최대응답비를 기초로 작성되었다. 해석결과 적절한 보강패턴을 선정한 경우 좋은 적합도의 향상을 보였으며 특히 감쇠지수의 값이 작은 경우 적합도의 개선효과가 뛰어났다.

• 한국안전학회지
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• 제27권5호
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• pp.148-157
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• 2012

Reliability-based design optimization (RBDO) problem is usually formulated as an optimization problem to minimize an objective function subjected to probabilistic constraint functions which may include deterministic design variables as well as random variables. The challenging task is that, because the probability models of the random variables are often assumed based on limited data, there exists a possibility of selecting inappropriate distribution models and/or model parameters for the random variables, which can often lead to disastrous consequences. In order to select the most appropriate distribution model from the limited observation data as well as model parameters, this study takes into account a set of possible candidate models for the random variables. The suitability of each model is then investigated by employing performance and risk functions. In this regard, this study enables structural design optimization and fitness assessment of the distribution models of the random variables at the same time. As the first paper of a two-part series, this paper describes a new design method considering probability model uncertainties. The robust performance of the proposed method is presented in Part 2. To demonstrate the effectiveness of the proposed method, an example of ten-bar truss structure is considered. The numerical results show that the proposed method can provide the optimal design variables while guaranteeing the most desirable distribution models for the random variables even in case the limited data are only available.

• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.181-189
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• 2022

The purpose of this study is to verify study models and examine a causal relationship among authenticity, job satisfaction, organizational commitment, quality of life and job achievement for amateur business team player. In order to achieve the purpose, this study conducted structural equation model analysis for study models consisting of extraneous variables after examining the authenticity(organization, leader) that amateur business players perceive and endogenous variables including job satisfaction, organizational commitment, quality of life, and job performance. The object of questionnaires in this study selected sports business team players nationwide as a population and 348 players were chosen as final effective samples by applying a convenient sampling method for offline and online questionnaires. The research tool for this study is a questionnaire. The two dimensions of authenticity were used by developing a scale. For all endogenous variables, the scales used in previous studies were modified and used according to the purpose of the study. This study analyzed the collected data, applying SPSS Win ver. 23.0 and AMOS 20.0 programs in order to analyze the characteristics of the study objects, describe questionnaires, and verify selected study hypothesis, individual hypothesis was verified after identifying the reliability and validity of measurement model, and the fitness verification of study models. In the results, all of the 8 hypothesis were adopted and the reciprocal relationship among each factors in the study model were observed.

• 대한간호학회지
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• 제43권3호
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• pp.399-408
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• 2013

Purpose: The study was done to construct and test a structural model to explain primipara breastfeeding behavior. Methods: The participants were 213 primiparas on postpartum wards. Data were analyzed using the PASW 18.0 and AMOS 19.0 programs. Results: Fitness statistics for the hypothetical model were appropriate ($x^2$=38.50, p=.070, GFI=.96, RMSEA=.05, AGFI=.93, NFI=.95, TLI=.97, CFI=.98, PNFI=.57, $x^2/df$=1.43). Breastfeeding behaviors were directly influenced by intention to breastfeed, perceived effectiveness of breastfeeding, and the amount of supplementary feeding. The amount of supplementary feeding had the largest direct impact on breastfeeding behavior. The largest total effect on breastfeeding behavior was intention to breastfeed. The environment of the maternity hospital indirectly influenced breastfeeding behavior. These factors explained 18.9% of variance in the primipara breastfeeding behavior. Conclusion: The results of the study indicate that in order to promote primipara breastfeeding the amount of supplementary feeding immediately after the birth should be limited and an environment that encourages exclusive breastfeeding in the hospital should be provided. The results also suggest it is necessary to provide nursing interventions that increase the intention to breastfeed and the perceived effectiveness of breastfeeding.

• 한국구조물진단유지관리공학회 논문집
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• 제16권6호
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• pp.134-142
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• 2012

본 연구는 탄현 에이스 11차 아파트에 위치한 14m 높이의 L형 옹벽의 장기 경사 계측치에 대한 System Identification연구로써, 옹벽구조물이 운용 중에 어떤 하중상태에서 어떻게 거동하는지를 이해하고, 이를 바탕으로 최적 모델을 규명하고, 최종적으로 옹벽의 이상상태를 판단할 수 있는 기준치를 제시하고자 하였다. 본 옹벽은 도심에 위치한 옹벽으로써는 보기 드물게 높고(14m), 인접한 건물과의 거리가 짧아서 붕괴 발생 시 큰 피해 가능성이 있다. 3개의 경사계로와 9개의 대기, 표면, 내부온도계로 구성된 경사 모니터링 시스템이 2004년 10월에 설치되어 2007년 7월까지 운용되었다. 모든 12 채널의 센서가 정상적으로 계측된 5개월 간의 연속된 데이터를 사용하여 두 가지 모델 1) 선형모델과 2) 상태방정식모델에 대하여 system identification을 수행하였다. 가용한 입력온도는 총 9이고, 이로부터 조합 가능한 총 511개의 입력온도 경우의 수에 대하여 규명데이터를 사용하여 시스템규명을 수행하고, 검증데이터에 대한 Fitness를 사용하여 최적모델을 선정하였다. 선형모델은 모델구조가 간단하지만 thermal dynamics를 표현하지 못하고, 약 68%의 Fitness를 얻을 수 있었고, 상태방정식 모델은 모델구조가 상대적으로 복잡하지만 thermal dynamics를 표현할 수 있고, 약 90%의 Fitness를 얻었다.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1361-1367
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• 2010

A series of O,O-dialkyl-1-phenoxyacetoxy-1-methylphosphonate analogues (1~22) as a new class of potent inhibitors of pyruvate dehydrogenase were synthesized and 3D-QSARs (three dimensional qantitative structure-activity relationships) models on the pre-emergency herbicidal activity against the seed of cucumber (Cucumus Sativa L.) were derived and discussed quantitatively using comparative molecular field analysis (CoMFA) and comparative molecular similarity indeces analysis (CoMSIA) methods. The statistical values of CoMSIA models were better predictability and fitness than those of CoMFA models. The inhibitory activities according to the optimized CoMSIA model I were dependent on the electrostatic field (41.4%), the H-bond acceptor field (26.0%), the hydrophobic field (20.8%) and the steric field (11.7%). And also, it was found that the optimized CoMSIA model I with the sensitivity to the perturbation ($d_q{^{2'}}/dr^2{_{yy'}}$ = 0.830) and the prediction ($q^2$ = 0.503) produced by a progressive scrambling analyses were not dependent on chance correlation. From the results of graphical analyses on the contour maps with the optimized CoMSIA model I, it is expected that the structural distinctions and descriptors that subscribe to herbicidal activities will be able to apply new an herbicide design.