• Journal of Science Education
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• v.37 no.2
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• pp.405-415
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• 2013

The purpose of this study was to investigate high school students in natural science track and engineering major university students' perceptions about the writing and composition education. A total of 318 high school students in natural science track from two high schools in a metropolitan area and 447 university students majoring in engineering from three universities participated in the survey and asked to response their perceived status and needs of writing education for science-engineering track. The survey instrument, developed by Lee et al.(2009), was used for this study. The data was analyzed through the SPSS 18.0 program for Windows for Multiple Response Frequency Analysis, Descriptive Statistics, Independent Samples t-test, and One-way Analysis of Variance. The results indicated that high school students relatively perceived that writing education was less necessary compared to university students. In addition, high school students found writing less difficult than university students do. In related to studying their experience with writing and composition education, almost no high school students have taken writing classes and university students have taken an average of one class. Most university students who took writing classes took basic writing classes that were not programmed for students in Science and Engineering. In the basic survey to revitalize writing and composition education for Science and Engineering students in different majors, the level of writing and composition education required by students in each major was different. Writing was considered most necessary for students majoring in Chemical Engineering, followed by students majoring in Mechanical Engineering and Electronic Engineering. The study of writing and composition education for high school and college should extend to studies on teachers or professors who teach writing, studies on contents and methods of writing education, and studies on the development of writing programs for different majors in university.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.307-314
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• 2006

Elevation differences within a paddy field relate strongly to plant health, crop homogeneity, and pest control. For precision agriculture (PA), the elevation within a field should be precisely controlled. We analyzed variation in elevation within two rice paddies over one crop cycle. The study took place in two rectangular plots (Field A and Field B, each $50m{\times}30m$). Elevations within the two plots were measured by a laser-equipped surveying instrument, that could determine elevations to precisions of 1 mm. The test fields were divided into grids with 30 squares; elevation was measured at the center of each $5{\times}10-m$ grid square. This study measured elevation during nine observation periods from pre-plowing to post-harvest. Descriptive statistics showed the highest elevations after plowing due to soil disturbance. One-way analysis of variance (ANOVA) revealed significant elevation differences before and after plowing and transplanting, although elevations were similar over the period of crop growth. Comparison of pre-plowing and post-harvest data showed differences in elevations, indicating that elevation changes occurred during plowing, rice transplanting, plant growth, and harvesting. In summary, the above statistical analyses indicated that elevation changes occurred due to plowing but not during the plant growth season or due to harvesting.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.205-216
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• 2021

This study aims to discuss ways needed to prepare their careers through relations between the personal internal factors perceived by college students in the process of career preparation and the external factors they experience during college life. To this end, the study conducted not only a questionnaire survey of 927 students at K University in Seoul but also hierarchical multiple regression analysis, independent two sample t-test, and one-way ANOVA (analysis of variance). The study set career preparation as a dependent variable, presented research models in four steps, and the explanatory power of each model was statistically significant. According to the findings of the study, both Model 1 and Model 2, gender had a significant impact on career preparation. Also, when self-directedness was added to Model 2, self-directedness had a greater impact on career preparation than gender did. When satisfaction with extracurricular activities was added to Model 3, this factor turned out to be helpful for career preparation. When college immersion, or a sense of belonging to college, was added to Model 4, the higher the sense of belonging students perceived, the more helpful they felt it for their career preparations. This study is expected to be helpful in preparing a policy to support college students' career preparation by grasping the relations between the personal characteristics of college students and career-related activities and college immersion they experience during college life.

• Korean Journal of Ecology and Environment
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• v.56 no.2
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• pp.161-171
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• 2023

The medium-large cladoceran species Simocephalus spp. predominantly occur in habitats with developed aquatic vegetation. Accordingly, due to Simocephalus' high contribution to zooplankton community biomass in the lake's littoral zone and wetland habitats, estimating their biomass is important to understand the matter cycling based on biological interactions within the aquatic food web. In this study, we reviewed the length-weight regression equations used previously to estimate Simocephalus biomass, directly measured S. serrulatus' body specification (length, width and area) and their biomass(dry weight) using instruments such as a microscopic digital camera and a microscale, and performed regression analysis between each other. When S. serrulatus biomass was estimated using the equation (Kawabata and Urabe, 1998) presented in 『Biomonitoring Survey and Assessment Manual』, Korea, errors between estimates and measures were relatively large compared to the S. serrulatus species-specific biomass estimate equation developed by Lemke and Benke (2003). In addition, both equations showed not only increasing trends in error (estimate-measure) with increasing S. serrulatus' body length, but also in error variance among similar-sized individuals. The results of regression analysis with dry weight by body specifications indicated that the most appropriate equation for estimating the biomass of S. serrulatus was derived from the width-dry weight exponential regression equation (R²=0.9555). The review and development study of such species-specific biomass estimation equations for zooplankton can be used as a tool to understand their role and function in aquatic ecosystem food webs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.322-332
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• 2019

This is a descriptive research study that aims to identify the effects of professionalism, job satisfaction, and resilience on the retention intention of home visiting nurses from the long-term care insurance system of Korea. Data were collected from self-administered surveys completed by 141 home visiting nurses of registered visiting-nursing institutions in the long-term care insurance database (April 1-May 31, 2019). Analyses were independent t-tests, one-way analysis of variance (ANOVA), the Scheffé test, Pearson's correlation analysis using SPSS/WIN 22.0, and multiple hierarchical regression analyses. Results showed that the mean professionalism score was 3.51/5, 3.27/5 for job satisfaction, 3.79/5 for resilience, and 4.04/5 for retention intention. A positive correlation existed between retention intention and professionalism (r = .272), job satisfaction (r = .201), and resilience (r = .530). The final regression model showed that resilience (β = .455, p < .001) and job satisfaction (β = .175, p = .016) significantly affect retention intention. The variables' model explanation power was 32.0% (F = 11.968, p < .001). The results show the need for strategies to improve resilience, followed by strategies to improve job satisfaction to increase the retention intentions of these home visiting nurses.

• Journal of Gifted/Talented Education
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• v.19 no.3
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• pp.411-432
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• 2009

This study analyzed the differences in parents' perceptions toward children's adjustments after grade skipping and early graduation. Parents of an early entrancer to K university(n=43) and parents of a non-early entrancer to K university(n=12) responded two kinds of questionnaires, one is for parents' perceptions towards children's needs for grade skipping and early graduation, and the other is for parents' perceptions toward children's adjustments to university experiences. Parents' responses were analyzed by MANOVA and MANCOVA. Results indicated that there was the significant difference in parents' perceptions for 'information about early graduation.' That is, parents of an early-entrancer had more 'information about early graduation' than their counterparts. However, there was no significant difference in parents' perceptions, after the effect of 'information about early graduation' on parents' perceptions toward children' academical and social-emotional adjustments. Thus, parents having more 'information about early graduation' considered more seriously the needs of grade skipping and early graduation in their children and worried less about their children's adjustments to university experiences.

• Journal of Korea Port Economic Association
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• v.25 no.2
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• pp.115-128
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• 2009

This study aims to identify the influence of exchange rate and national economy on Export through container ports (Busan Port, Incheon Port, Gwangyang Port, and Pyeongtaek Port) from January 2001 to October 2007. This study carried a unit root test on the results of the analysis and failed to reject the null hypothesis that level variables have a unit root at the level of 1%. However, it carried out a unit root test on the variables by the first order difference and succeeded in rejecting the null hypothesis aforementioned at the level of 1%. As a result of the cointegration test, it was found that the model is stable. When this study carried out a variance decomposition on the prediction error of export at container various container ports, it found 89% for Busan Port, 83% for Incheon Port, 86% for Gwangyang Port, and 84% for Pyeongtaek Port. These figures indicate that such variables significantly account for export at container ports. For Busan Port, Step 2 of exchange rate showed negative (-) effect, and Step 3 shows an extreme transition into a positive (+) effect. The national economy showed an extreme change from Steps 2 to Step 7, and then a positive effect has been maintained. The Incheon Port, Gwangyang Port and Pyeongtaek Port showed similar trends to Busan Port. From Step 7, it seems that they have Shifted to more stable trends.

• Journal of Korea Port Economic Association
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• v.35 no.2
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• pp.61-76
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• 2019

The purpose of this study is to use the EGARCH model and Granger causality test to analyze how the change in the BDI affects the Korean stock price volatility. The main analysis results are summarized as follows. First, according to the results of the mean equation, the change in the BDI is significant in large-cap stocks, as well as in the manufacturing, service, and chemistry indexes, but not in others. This implies that the Korean stock market does not respond appropriately to the maritime market situation; further, the increase in demand for raw materials has not led to a real economic recovery. Second, in the result of the variance equation, the coefficient on the change in the BDI is negative(-), and the change in the BDI is significant for all size indexes. Particularly, the change in the BDI has a greater impact on the volatility of small-cap stocks than that of large-cap stocks. The results of the analysis of the sector indexes were statistically significant for the service, financial, construction, and electric and electronics industries, but not for the manufacturing and chemical industries. In particular, the changes in the BDI have the greatest impact on the construction industry. Third, according to the Granger causality test results, the change in the BDI leads the financial industry and construction industry. There is, however, no relationship between the BDI and the other indexes. This shows that change in the shipping freight index can be used to predict the volatility in the Korean stock market. This can help investors and policymakers make better decisions.

• The Journal of the Acoustical Society of Korea
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• v.42 no.4
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• pp.329-344
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• 2023

In this study, we comprehensively analyze the generalization performance of various deep learning-based active sonar target classifiers when applied to small and imbalanced active sonar datasets. To generate the active sonar datasets, we use data from two different oceanic experiments conducted at different times and ocean. Each sample in the active sonar datasets is a time-frequency domain image, which is extracted from audio signal of contact after the detection process. For the comprehensive analysis, we utilize 22 Convolutional Neural Networks (CNN) models. Two datasets are used as train/validation datasets and test datasets, alternatively. To calculate the variance in the output of the target classifiers, the train/validation/test datasets are repeated 10 times. Hyperparameters for training are optimized using Bayesian optimization. The results demonstrate that shallow CNN models show superior robustness and generalization performance compared to most of deep CNN models. The results from this paper can serve as a valuable reference for future research directions in deep learning-based active sonar target classification.

• Science of Emotion and Sensibility
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• v.22 no.3
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• pp.47-54
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• 2019

We examined previous studies of the correlation analysis of heart rate variability as a method to reduce the stress caused by outside noise during driving, and we investigated whether there are electrocardiographic changes when drivers play music, which provides a stable sound source amid the noise. Because the number of cars increases every year, drivers and passengers show an increase in stress caused by outside noise. The stress from outside noise while a person is driving can cause several disorders, such as anxiety, immunosuppression, depression, and heart disease. Subjects in this study operated a vehicle simulator to reduce the stress from outside noise and were given different auditory stimuli, and we studied the drivers' responses to the stimuli. Repeated-measures analysis of variance revealed a significant differences between subjects exposed to different auditory stimuli (ρ < 0.05). Through post hoc analyses, we examined these differences. We found significant differences between factor 1 (stability) and factor 2 (simulation driving), between factor 1 (stability) and factor 3 (driving + police siren), and between factor 1 (stability) and factor 4 (driving + police siren + music). In addition, the factor that produced the highest level of sympathetic nervous system activity was factor 4 (driving + police siren + music), followed by factor 3 (driving + police siren), factor 2 (driving), and factor 1 (stability). In conclusion, even when a police siren was heard during driving, there were no significant differences on electrocardiograms (ECGs). In addition, even when the siren was heard over the music, there was no difference on the ECGs (ρ < 0.01). In future studies, investigators should determine which types of music help stabilize the heart rate during driving.