• Journal of Fisheries and Marine Sciences Education
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• v.19 no.1
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• pp.8-18
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• 2007

In order to define their relative influence, this study analyzed causal relationships between school adjustment of middle school students and such related variables as locus of control and stress, including clarification of other significant variables affecting school adjustment. Participants were a sample of 331 students from 3 middle schools in Busan. Correlation, analysis of covariance structure modeling, and model-fitness tests were applied to the data. Results indicated that stress on the school, home, social relationships, and self has the more significant influence on the school adjustment, and the locus of control has relatively low influence.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.3
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• pp.312-320
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• 1990

Analysis and lattice implementation of Extended Instrumental Variable (EIV) methods for high resolution spectral analysis are presented. The performance of EIV is improved by using prefilters and the unbiasness of EIV is proved by using the fact that residual processes are white. We derive the order and time update formulas for the covariance lattice algorithm which is particularly useful in case of short data or nonstationary processes. The ARMA model can be modeled as two channel AR processes. Using this model, the lattice algorithms of EIV are derived. Computer simulations are performed to show the usefulness of the proposed algorithms.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1419-1424
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• 2018

Very short-term electric load forecasting is essential for real-time power system operation. In this paper, a very short-term electric load forecasting technique applying the Kalman filter algorithm is proposed. In order to apply the Kalman filter algorithm to electric load forecasting, an electrical load forecasting algorithm is defined as an observation model and a state space model in a time domain. In addition, in order to precisely reflect the noise characteristics of the Kalman filter algorithm, the optimal error covariance matrixes Q and R are selected from several experiments. The proposed algorithm is expected to contribute to stable real-time power system operation by providing a precise electric load forecasting result in the next six hours.

• Journal of Navigation and Port Research
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• v.37 no.4
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• pp.329-335
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• 2013

This paper is to develop the position error equations including the attitude errors, the errors of nadir and ship's heading, and the errors of ship's position in the free-gyro positioning and directional system. In doing so, the determination of ship's position by two free gyro vectors was discussed and the algorithmic design of the free-gyro positioning and directional system was introduced briefly. Next, the errors of transformation matrices of the gyro and body frames, i.e. attitude errors, were examined and the attitude equations were also derived. The perturbations of the errors of the nadir angle including ship's heading were investigated in each stage from the sensor of rate of motion of the spin axis to the nadir angle obtained. Finally, the perturbation error equations of ship's position used the nadir angles were derived in the form of a linear error model and the concept of FDOP was also suggested by using covariance of position error.

• Mood & Emotion
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• v.15 no.3
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• pp.123-129
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• 2017

Objective : To present effects of depression, optimism and gratitude on suicidal ideation of patients with depressive disorders. Methods : Using analyses of covariance (ANCOVA), scores on the Beck Depression Inventory (BDI), Life Orientation Test-Revised (LOT-R), and Gratitude Questionnaire (GQ-6) were compared between depressive disorder patients with higher and lower levels of suicidal ideations. A linear regression model was fitted to detect independent correlates for suicidal ideations. Results : Significantly greater level of depression and lower level of gratitude were characterized by depressive disorder patients with higher level of suicidal ideations. The fitted regression model presented that depression and gratitude were independent correlates for suicidal ideations in patients with depressive disorders. Conclusion : Our findings suggest that gratitude may be associated with lowering the level of suicidal ideation in patients with depression.

• Journal of Preventive Medicine and Public Health
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• v.47 no.1
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• pp.64-71
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• 2014

Objectives: Physical activity behavior begins to decline during adolescence and continues to decrease throughout young adulthood. This study aims to explain factors that influence physical activity behavior in a sample of female adolescents using a health promotion model framework. Methods: This cross-sectional survey was used to explore physical activity behavior among a sample of female adolescents. Participants completed measures of physical activity, perceived self-efficacy, self-esteem, social support, perceived barriers, and perceived affect. Interactions among the variables were examined using path analysis within a covariance modeling framework. Results: The final model accounted for an $R^2$ value of 0.52 for physical activity and offered a good model-data fit. The results indicated that physical activity was predicted by self-esteem (${\beta}$=0.46, p<0.001), perceived self-efficacy (${\beta}$=0.40, p<0.001), social support (${\beta}$=0.24, p<0.001), perceived barriers (${\beta}$=-0.19, p<0.001), and perceived affect (${\beta}$=0.17, p<0.001). Conclusions: The findings of this study showed that the health promotion model was useful to predict physical activity behavior among the Iranian female adolescents. Information related to the predictors of physical activity behavior will help researchers plan more tailored culturally relevant health promotion interventions for this population.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.2
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• pp.129-139
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• 2016

This paper presented a robust ship scheduling model using the quadratic programming problem. Given a set of available carriers under control and a set of cargoes to be transported from origin to destination, a robust ship scheduling that can minimize the mean-variance objective function with the required level of profit can be modeled. Computational experiments concerning relevant maritime transportation problems are performed on randomly generated configurations of tanker scheduling in bulk trade. In the first stage, the optimal transportation problem to achieve maximum revenue is solved through the traditional set-packing model that includes all feasible schedules for each carrier. In the second stage, the robust ship scheduling problem is formulated as mentioned in the quadratic programming. Single index model is used to efficiently calculate the variance-covariance matrix of objective function. Significant results are reported to validate that the proposed model can be utilized in the decision problem of ship scheduling after considering robustness and the required level of profit.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.1
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• pp.68-77
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• 2018

Purpose: The aim of this study was to establish a hypothetical model on silence regarding patient safety and to verify the model's goodness of fit and hypotheses. Methods: The participants in this study were 330 registered nurses working in tertiary hospitals with over 300 beds. Data were collected between July 1, and August 30, 2017, from nurses who agreed to participate. A covariance structure analysis was performed. Results: The model of fit index was $x^2=59.54$, normed $x^2=2.29$, GFI=.97, AGFI=.93, SRMR=.05, NFI=.99, CFI=.95 and RMSEA=.05. The organizational culture had an influence on patient safety motivation (${\beta}=.26$, p=.003) and attitude (${\beta}=.43$, p<.001). RN-MD collaboration had an influence on patient safety motivation (${\beta}=.33$, p<.001), attitude (${\beta}=.35$, p<.001), and patient safety silence (${\beta}=-.17$, p=.026). Supervisory trust had an influence on patient safety motivation (${\beta}=.26$, p<.001), attitude (${\beta}=.12$, p=.036), and patient safety silence (${\beta}=-.23$, p=.002). Patient safety motivation had an influence on patient safety silence (${\beta}=-.33$, p=.006). The model of patient safety silence explained 36.0% of the variances. Conclusion: This study is meaningful in that it provides basic data for nursing education and program development for rejecting patient safety silence.

• Journal of Korean Academy of Nursing
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• v.34 no.1
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• pp.172-181
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• 2004

Purpose: This study was designed to construct a structural model for explaining negative outcomes of anger in female adolescents. Methods: Data was collected by questionnaires from 199 female adolescents ina female high school in Seoul. Data analysis was done with SAS for descriptive statistics and a PC-LISREL Program for Covariance structural analysis. Results: The fit of the hypothetical model to the data was moderate, thus it was modified by excluding 7 paths and adding free parameters to it. The modified model withthe paths showed a good fit to the empirical data($x^2$ =5.62, p=.69, GFl=.99, AGFl=.97, NFI=.99, NNFI=l.01, RMSR=.02, RMSEA=.00). Trait anger, state anger, and psychosocial problems were found to have a significant direct effect on psychosomatic symptoms. State anger, psychosocial problems, and learning behaviorswere found to have direct effects on depression of female adolescents. Conclusion: The derived modelis considered appropriate for explaining and predicting negative outcomes of anger in female adolescents. Therefore, it can effectively be used as a reference model for further studies and is a suggested direction in nursing practice.

• Journal of Korean Academy of Nursing
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• v.48 no.5
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• pp.588-600
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• 2018

Purpose: The purpose of this study was to test a model of nursing competencies of nursing simulation learners. The conceptual model was based on the theory of Jeffries's simulaton theory. Methods: Data collection was conducted in October 2017 for 310 students from two nursing universities in Kyungbuk area for 20 days. Data analysis methods were covariance structure analysis using SPSS 21.0 and AMOS 22.0 statistical programs. Results: The hypothetical model was a good fit for the data. The model fit indices were comparative fit index=.97, normed fit index=.94, Tucker-Lewis Index=.97, root mean square error of approximation=.44, and standardized root mean square residual=.04. Teacher factors were directly related to simulation design characteristics, and it was confirmed that the curriculum, classroom operation and teaching method of the instructors were important factors. Learner factors were found to have a direct effect on nursing competence, self-confidence, and clinical performance that belong to nursing capacity. In particular, the results of this study indicate that the simulation design characteristics have a partial mediating effect on learner factors and clinical performance, and a complete mediating effect on learner factors and clinical judgment ability. Conclusion: In order to improve the learner's clinical performance and clinical judgment ability, it is necessary to conduct practical training through nursing simulation besides preparing the learner and the educator.