• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.83-83
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• 2021

수리구조물로 인한 유황변화와 함께 기후변화로 기인하는 강우변동성 및 온도 증가는 수생태 전반에 악영향을 미치는 주요 인자로 작용하고 있다. 특히, 최근 가뭄으로 인한 유황감소 및 폭염 등으로 여름철 녹조의 발생 빈도 및 강도 증가가 지속적으로 증가하고 있다. 본 연구에서는 하천에서 계측되고 있는 Cyanobacteria 개체수를 기반으로 녹조발생 여부를 전망할 수 있는 모형을 개발하고자 한다. Cyanobacteria 개체수를 기준으로 녹조발생 여부를 판단할 수 있도록 기준값(threshold)을 설정하고 binary 형태로 시계열을 구성하였다. 이를 Bernoulli 모형에 적합하여 녹조 발생 여부를 판단할 수 있도록 모형을 개발하였다. 하천을 따라 나타나는 녹조는 시공간적으로 유사한 특성을 가지며, 이러한 점을 고려하여 여러 관측지점을 동시에 모델링하는 것이 모형의 효율성과 예측성 측면에서 유리하다. 본 연구에서는 낙동강을 따라 여러 녹조관측지점을 대상으로 동시에 모델링이 가능하도록 다변량 Bernoulli 모형 기반의 녹조 예측 모형을 제시하고 과거 자료를 대상으로 모형의 적합성을 평가하였다. 다양한 지표를 기준으로 교차검증을 수행하였으며, 기존 물리적 모델에 비해 모형의 예측성능 및 효율성 측면에서 우수성을 확인할 수 있었다.

• Science of Emotion and Sensibility
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• v.17 no.1
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• pp.79-92
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• 2014

This study is aimed at minimizing the errors in using a sensitivity evaluation model that could occur when sensitivity analysis method is actively used for design evaluation. To extract words of a contrantion-type model by product, interior space, and streetscape design, primary word refinement was conducted with the words extracted from preceding studies. The analysis revealed that 19 words were used in all three fields. A reliability analysis revealed that different words had a bad impact on the reliability in each field. The applicability was reviewed through reliability analysis of EPA model as contraction-type and PAD model as inference-type. The results are as follows. Although the reliability of the contrantion-type model was higher than that of inference-type model in all three fields, the differences in Cronbach's Alpha were small. Also, When the reliability was analyzed after deleting the words that had a bad impact on reliability, the differences in the reliability's coefficients were clearly significant. Therefore, it is necessary to select words suitable for sensitivity evaluation target and objectivity of the evaluation can be boosted by using a proper model. Analysis of the sensitivity evaluation model suitable for future environmental evaluation should be analyzed with various statistical methods, beyond verification of reliability.

• 한국정보교육학회:학술대회논문집
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• 2007.01a
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• pp.359-364
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• 2007

Wiki 웹토론 시스템의 목적은 지식을 공유하고 자기 주도적으로 학습을 가능하게 하는 토론을 활성화시키는 데 있다. 그러나 이러한 장점에도 불구하고 가정의 컴퓨터 보급률이라든지 인터넷 사용 등의 제반환경여건에 따라 원활한 수업이 이루어지지 않았다. 따라서 면대면 현장학습뿐만 아니라 온라인 환경과 기술요소에 따른 다양한 학습활동들이 필요하다. 블렌디드 러닝 (Blended Learning)이란 적합한 시간에 적합한 사람에게 적합한 기술을 개인에 적합한 학습스타일에 맞추기 위해 적합한 학습관련의 기술을 적용함으로써 학습목표 성취에 초점을 두는 학습형태이다. 블렌디드 러닝에 있어서 학습은 지속적인 과정이며 오프라인학습공간과 결합하여 학습의 장을 넓히는 것이다. 학습자의 관심을 끌어내어 교육의 효과성을 극대화하며 학습 프로그램의 개발이나 과정실행에서 적절한 방법으로 혼합함으로써 시간과 비용을 최적화할 수 있다. 본 연구에서 제시한 블렌디드 러닝 교수학습모형은 Wiki 웹토론 시스템을 보다 효율적으로 활용할수 있게 하였다. 본 모형의 특징은 첫째, 토론에 앞서 오프라인 학습으로 학습목표확인과 수업안내를 하여 학생들로 하여금 학습목표인지와 수업의 흐름을 보다 잘 파악할 수 있게 하였다. 둘째, 토론 후 교사의 강의가 오프라인 학습으로 이루어지도록 하여 학생들에게 배운 내용을 정리할 수 있는 기회를 제공하여 보다 충실한 수업이 될 수 있었다. 셋째, 토론 후 학습자-교사자 및 학습자 상호피드백이 이루어질 수 있도록 하였다.

• Communications for Statistical Applications and Methods
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• v.4 no.1
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• pp.65-74
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• 1997

1996년 15대 국회의원 선거의 소속별 예측의석수와 실제의석수에 대한 정방형 분할표를 구하여 적절한 대수선형모형을 적합시키고 모형의 해석을 시도하였다.

• The Korean Journal of Applied Statistics
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• v.22 no.6
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• pp.1265-1275
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• 2009

In this paper, we investigated the composite covariance structure models for repeated measures data with multiple repeat factors. When the number of repeat factors is more than three, it is infeasible to fit the composite covariance models using the existing statistical packages. In order to fit the composite covariance structure models to real data, we proposed two approaches: the dimension reduction approach for repeat factors and the random effect model approximation approach. Our proposed approaches were illustrated by using the blood pressure data with three repeat factors obtained from 883 subjects.

• Journal of the Korean Data and Information Science Society
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• v.25 no.2
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• pp.423-429
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• 2014

This paper discusses a method for getting Type I sums of squares by projections under a two-way fixed-effects model when variances of errors are not equal. The method of weighted least squares is used to estimate the parameters of the assumed model. The model is fitted to the data in a sequential manner by using the model comparison technique. The vector space generated by the model matrix can be composed of orthogonal vector subspaces spanned by submatrices consisting of column vectors related to the parameters. It is discussed how to get the Type I sums of squares by using the projections into the orthogonal vector subspaces.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.143-154
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• 2016

This study was designed to construct and test structural equation modeling on nurses' emotional labor including antecedents and consequences based on the model of Morris and Feldman (1997). A total of 247 nurses working at secondary and tertiary hospitals in three provinces responded the questionnaires. Emotional labor was measured by frequency of emotional labor, attentiveness of required display rules and emotional dissonance. Routineness of job, job autotomy and organizational support were measured as antecedents; and emotional exhaustion, job satisfaction and organizational commitment were included as the consequences of nurses' emotional labor. Data were analyzed by SPSS 21.0 and AMOS 21.0. The model fitness indices for the hypothetical model showed NFI=.94, CFI=.97, and RMSEA=.07. Job autonomy and perceived organizational support had significant effects on emotional labor. The emotional labor influenced positively emotional exhaustion and negatively job satisfaction and organizational commitment. Nurses' emotional labor mediates between job characteristics and nurses' psychologic results indicating more autonomy and support can reduce nurses' emotional labor and then increase their satisfaction and organizational commitment, and decrease emotional exhaustion.

• Journal of Digital Convergence
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• v.15 no.2
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• pp.251-262
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• 2017

This study distinguishes between factors that affect mental health of college students, establishes an effective approach to integrating model building, mental health promotion, and development of nursing intervention based on the Bronfenbrenner's ecological system theory. The study method investigate the causal relationship between the factors. The SPSS 20.0 program was used for general characteristics and mental health related characteristics. The fitness of the model was verified and the Amos 20.0 program was used for hypothesis verification. In the study, the fit index of the model was $x^2=614.90$ (p = .000), Q value = 3.5, GFI = .88, AGFI = .84, NFI = .92, NNFI = .94, CFI = .02, and RMSEA = .08, respectively. The results showed that stress was the most influential on mental health, and that stress coping strategies, self - esteem and parenting attitude affect mental health. In order to improve the mental health of college students, intervention should be carried out to develop nursing interventions to improve stress management, self - esteem, and coping with stress.

• Journal of Navigation and Port Research
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• v.32 no.1
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• pp.81-88
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• 2008

The forecast of a container traffic has been very important for port plan and development. Generally, statistic methods, such as regression analysis, ARIMA, have been much used for traffic forecasting. Recent research activities in forecasting with artificial neural networks(ANNs) suggest that ANNs can be a promising alternative to the traditional linear methods. In this paper, a hybrid methodology that combines both ARIMA and ANN models is proposed to take advantage of the unique strength of ARIMA and ANN models in linear and nonlinear modeling. The results with port traffic data indicate that effectiveness can differ according to the characteristics of ports.

• The Korean Journal of Applied Statistics
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• v.24 no.4
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• pp.677-693
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• 2011

In this paper, we consider Bayesian approaches to zero inflated Poisson model, one of the popular models to analyze zero inflated count data. To generate posterior samples, we deal with a Markov Chain Monte Carlo method using a Gibbs sampler and an exact sampling method using an Inverse Bayes Formula(IBF). Posterior sampling algorithms using two methods are compared, and a convergence checking for a Gibbs sampler is discussed, in particular using posterior samples from IBF sampling. Based on these sampling methods, a real data analysis is performed for Trajan data (Marin et al., 1993) and our results are compared with existing Trajan data analysis. We also discuss model selection issues for Trajan data between the Poisson model and zero inflated Poisson model using various criteria. In addition, we complement the previous work by Rodrigues (2003) via further data analysis using a hierarchical Bayesian model.