• Journal of the Society of Naval Architects of Korea
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• v.48 no.2
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• pp.147-157
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• 2011

A RANS(Reynolds averaged Navier-Stokes) based numerical method is developed for the evaluation of ship resistance and self-propulsion performances. In the usability aspect of CFD for the hull form design, the field grid around practical hull forms is generated by solving a grid Poisson equation based on the hull surface grid generated from station offsets and centerline profile. A body force technique is introduced to model the effects of the propeller in which the propeller loads are obtained from potential flow analysis using an unsteady lifting surface method. The free surface is captured by using a two-phase level-set method and the realizable $k-{\varepsilon}$ model is used for turbulence closure. The hull attitude in vertical plane, i.e., trim and sinkage, is calculated by using a quasi-steady method and then considered in the computation by translating and rotating the grid system according to the values. For the validation of the proposed method, the numerical results of resistance tests for KCS, KLNG, and KVLCC1 and of self-propulsion test for KCS are compared with experimental data.

• The Journal of Korean Academic Society of Nursing Education
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• v.21 no.2
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• pp.215-226
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• 2015

Purpose: This study aimed to develop a self-assessment tool to evaluate program outcomes of nursing students in Korean nursing undergraduate education. Methods: The instrument development process consisted of literature review, focus group interviews, and item validation. A total of 117 items were analyzed through content validity testing. Data was gathered from 302 nursing students in Korea and analyzed using SPSS 21.0. Results: To construct validity, principal component analysis and Varimax rotation were used, and 12 factors, with a cumulative explanatory variance of 69.16%, were determined from 79 items. For internal consistency and reliability, Cronbach's ${\alpha}$ was .91. The half-split reliability results were .84 and .85, and the ROC curve showed an optimal cutpoint at 227. A five-point Likert scale was used for scoring. Conclusion: This instrument was found to have fair validity and reliability as a self-assessment tool for nursing student learning outcomes. Therefore, it can be used to evaluate program outcomes indirectly in nursing schools.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.7 s.112
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• pp.677-682
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• 2006

In the case of aeroacoustic test in windtunnel, measurement accuracy is reduced by not only Doppler effects but also by the microphone self noise due to airflow and high turbulence in the wall boundary layer. Microphone array measurements can be easily utilized for the solutions of these problems. In this paper, geometrical optics approach and diagonal term elimination of cross spectral matrix was introduced to the de-dopplerization and self noise reduction methods for the microphone array measurement. For the validation, beamforming tests for sinusoidal point source were performed in the closed type test section of windtunnel, and their performances of beam width and sidelobe rejection were significantly improved.

• Korean Journal of Health Education and Promotion
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• v.19 no.2
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• pp.15-22
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• 2002

The purpose of the study was to assess relationship between smoking-related questionnaire and urinary cotinine. Seventy-five students of each one class of the first and second grade in one vocational school were administered the smoking-related items of the Youth Risk Behavior Survey October 2000, after which urine samples were collected. Urinary cotinine was detected by qualitative AccuSign Nicotine immunoassay. Positivity of urinary cotinine was detected in 29 of 75 students (38.7%). Kappa coefficients between self-reported smoking behaviors and positivity of urinary cotinine were all statistically significant, showing 0.41, 0.50, 0.28, 0.71 in lifetime smokers, regular smokers, current smokers, and current frequent smokers, respectively. These results showed that self-reported questionnaire may be useful in smoking-related survey and qualitative urinary cotinine may be used as validation of self-reported questionnaire.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.822-825
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• 2005

In the case of aeroacoustic test in windtunnel, measurement accuracy is reduced by not only Doppler effects but also by the microphone self noise due to airflow and high turbulence in the wall boundary layer. Microphone array measurements can be easily utilized for the solutions of these problems. In this paper, geometrical optics approach and diagonal term elimination of cross spectral matrix was introduced to the de-dopplerization and self noise reduction methods for the microphone array measurement. For the validation, beamforming tests for sinusoidal point source were performed in the closed type test section of windtunnel, and their performances of beam width and sidelobe rejection were significantly improved.

• Journal of Korean Academy of Nursing
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• v.37 no.6
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• pp.835-843
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• 2007

Purpose: This study examined the fitness of a path model on the relationship among stress, self-esteem, aggression, depression, suicidal ideation, and violent behavior for adolescents. Methods: The subjects consisted of 1,177 adolescents. Data was collected through self-report questionnaires. The data was analyzed by the SPSS and AMOS programs. Results: Stress, self-esteem, aggression, and depression showed a direct effect on suicidal ideation for adolescents, while stress, self-esteem, and aggression showed an indirect effect on suicidal ideation for adolescents. Stress, self-esteem, aggression, and suicidal ideation showed a direct effect on violent behavior for adolescents, while stress, self-esteem, aggression, and depression showed an indirect effect on violent behavior for adolescents. The modified path model of adolescent's suicidal ideation and violent behavior was proven correct. Conclusion: These results suggest that adolescent's suicidal ideation and violent behavior can be decreased by reducing stress, aggression, and depression and increasing self-esteem. Based on the outcomes of this study, it is necessary to design an intervention program that emphasizes reducing stress, aggression, and depression and increasing self-esteem in order to decrease adolescents' suicide ideation and violence.

• Journal of Korean Academy of Nursing
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• v.50 no.1
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• pp.132-146
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• 2020

Purpose: The purpose of this study was to develop a new version of Spirituality Assessment Scale (N-SAS) and verify its reliability and validity. Methods: The total of 59 preliminary items for the N-SAS were selected through a literature review, two rounds of experts' content validation, cognitive interviews, and pre-tests. Verification of its reliability and validity was divided into two phases. In Phase I, questionnaires were collected from 219 adults. Reliability was tested using Cronbach's alpha, validity with item analysis, and exploratory factor analysis. In Phase II, questionnaires developed based on the results of Phase I were collected from 225 adults. Reliability was tested using Cronbach's alpha, validity with confirmatory factor analysis, and criterion validity. Results: The final version of the N-SAS comprised two dimensions (vertical and horizontal), four domains (relationship with God; meaning of life and self-integration; self-transcendence; and relationship with others, neighborhoods, and nature), and 44 items were identified. Total Cronbach's α was .97; those of each subscale ranged from .79 to .98. N-SAS scores were positively correlated with the scores of Howden's Spiritual Assessment Scale (r=.81, p<.001). Conclusion: Findings suggest that the N-SAS can be used to measure spirituality in adults. The use of N-SAS is expected to facilitate perceiving patient's spiritual needs and providing spiritual care.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.33-43
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• 2019

A comparison between sea trial measurements and full-scale CFD results is presented for two self-propelled ships. Two ships considered in the present study are: a general cargo carrier at Froude number $F_n=0:182$ and a car carrier at $F_n=0:254$. For the general cargo carrier, the propeller rotation rate is fixed and the achieved speed and trim are compared to sea trials, while for the car carrier, the propeller rotation rate is adjusted to achieve the 80% MCR. In addition, three grids are used for each ship in order to assess the grid refinement sensitivity. All simulations are performed using the Naval Hydro pack based on foam-extend, a community driven fork of the OpenFOAM software. The results demonstrate the possibility of using high-fidelity numerical methods to directly calculate ship scale flow characteristics, including the effects of free surface, non-linearity, turbulence and the interaction between propeller, hull and the flow field.

• Korean Journal of Childcare and Education
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• v.20 no.2
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• pp.105-126
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• 2024

Objective: The study aimed to develop and validate a tool for assessing daycare center organizational competence and for autonomously managing childcare quality. Methods: Through literature review and expert reviews, items were derived and validated using the Content Validity Index. Data from a survey involving 216 directors and 509 teachers were analyzed using SPSS and AMOS to assess reliability and conduct confirmatory factor analysis. Results: Results revealed a 36-item diagnostic tool across four subcategories: shared values (6 items), training abilities (18 items), environmental support (6 items), and organizational promotion (6 items). A diagnostic tool named S.T.E.P+ was developed, named after the first letters of the four subfactors. Skewness and kurtosis were within normality assumptions. Good fit indices (CFI, TLI) and low SRMR and RMSEA values indicated a satisfactory model fit. Cronbach's α values showed high reliability for all factors. The tool enables autonomous diagnosis of childcare quality. Conclusion/Implications: This tool can effectively autonomously diagnose whether a daycare center is providing quality childcare.

• Korean Journal of Childcare and Education
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• v.7 no.3
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• pp.239-257
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• 2011

The purpose of this study was to redefine and validate the motivational self-concept for child-care teachers. Based on related researches, items were remodified to be good enough to use for studying child-care teachers' motivational self-concept. Redefined items were analysed by factor analysis and validated by use of child-care teachers' professional recognition and their ego-resiliency. Researchers have garnered data from 321 child care teachers as convenience samples who are engaged in child care centers in Seoul and Kyunggi province by using questionnaire research methods. We have eliminated questions that are .40 below communality, questions by conducting exploratory factor analysis. As a result, 6 factors and 23 items were selected; 6 factors have indicated that it explained 77.12% of total variate motivational self-concept rating scale and ${\alpha}$ of Cronbach that of total items indicated acceptable level. After examining relevancy of child-care teachers' professional recognition and ego-resiliency to verify compliant feasibility of the motivational self-concept rating scale, the relation between motivational self-concept and professional recognition was .604(p<0.001) indicating significant static correlation and the relation between motivational self-concept and ego-resiliency was 4.456(p<0.01) indicating significant static correlation. Through this result, it is verified that motivational self-concept rating scale has compliant feasibility in professional recognition and ego-resiliency.