• Journal of Aerospace System Engineering
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• v.14 no.spc
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• pp.7-12
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• 2020

In this paper the new revision of Korean Airworthiness Standards (KAS) - Emissions was proposed for enforced environmental standards. The Aircraft Engine Fuel Venting and Exhaust Emissions Requirements have been only defined for smoke, HC, CO and NOx as management items in previous KAS. However, this standard has not covered the current situation that International Civil Aviation Organization (ICAO) and United States Environmental Protection Agency (EPA) enforced environmental regulations, such as emissions trading system, limitation of CO₂ emissions and restriction of exhaust gas. In order to overcome these outdated situations, we presented the new requirements for aircraft exhaust gas emissions standard of Korea based on the latest standards of United States, Europe and other countries.

• Journal of The Korean Association of Information Education
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• v.21 no.3
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• pp.285-296
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• 2017

In this study, we conduct SW education using robot in elementary school, to examine the effects of SW education using robot on CT and gender differences. In order to achieve the purpose of this study, SW education using robot was conducted to 143 students in 5, 6 grade in GyeongGi. After collecting data, we examined mean difference using matched pair t-test and ANCOVA. The results of this study were as follows: The SW education using robot is associated with significant improvements in CT, however, computational concepts is not associated with significant improvement in high initial score sub sample. And CT is not associated with gender. This study was investigated effects of the SW education using robot and identify gender differences. And expanded the understanding of the SW education using robot.

• Journal of Korean Society of Archives and Records Management
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• v.20 no.4
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• pp.129-146
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• 2020

This study aims to investigate the outcomes and limitations of research studies on records and archives organization published in Korea. In particular, it will serve as an in-depth examination of the contribution of this area of research to the improvements and changes in the country's records management field. To this end, 150 journal articles related to the records and archives organization were gathered. After extracting refined keywords from the titles and author-assigned keywords, terminology analysis and contents analysis were conducted. On the one hand, terminology analysis (frequency and network analysis) identified frequently discussed topics and the relationships between them. On the other hand, through content analysis, the study revealed the detailed contents regarding the two main topics and their meanings.

• Research in Community and Public Health Nursing
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• v.16 no.4
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• pp.458-466
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• 2005

Purpose: The purpose of this study was to determine the relation between test anxiety and mental health in adolescents. Method: The subjects were 450 students of two academic high schools in J City, who were selected through convenient sampling. Data were collected through a survey using a structured questionnaire from September 1st to 15th 2005. Collected data were analyzed using SPSS 10.0 for Windows through descriptive analysis, Pearson's Correlation Coefficient, t-test, ANOVA, Scheffe's test and stepwise multiple regression. Result: The mean score of test anxiety was 2.40 (range:1.13-3.81) and that of mental health was 2.77 (range:0.64-5.03). A significant negative correlation was observed between test anxiety and mental health (r=-0.28, p=.000). Test anxiety was significantly different according to adolescents' general characters such as gender (t=-1.98, p=.048), grade (F=3.54, p=.030), school life satisfaction (F=10.73, p=.000) and relationship with the teacher (F=11.60, p=.000). Mental health was significantly different according to adolescents' general characters such as religion (t=2.14, p=.032) and school life satisfaction (F=4.13, p=.017). The most powerful predictor of mental health was test anxiety and it, combined with religion, accounted for 9.0% of variance in mental health in adolescents. Conclusion: Test anxiety and mental health was found to be in a significant negative correlation with each other in adolescents. Therefore, nursing intervention programs for adolescents needs to reduce their test anxiety to improve their mental health.

• Korean journal of applied entomology
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• v.39 no.1
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• pp.5-12
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• 2000

The sweetpotato whiteflies, Bemisia tabaci(Gennadius), were found recently in Korea on Glycine max, Euphorbia pulcherrima, and Rosa hybrida. The biotype identity of Bemisia tabaci in Korea was determined by several DNA markers including the random amplified polymorphic DNAs, and restriction fragments length polymorphism of mitochondrial 12S and 16S rRNA genes. The electromorph profiles of DNA fragments from the rose(Jincheon) and poinsettia(Seoul) populations in Korea are both identical to those of B biotypes distributed in Australia, Israel, and Japan. The populations of B. tabaci collected on Glycine max, Ipomea batatas, and Perilla frutescens in different localities retained the same DNA markes with the population from Lonicera japonica and shikoku of Japan. These populations are non-B biotype and considered as an indigenous type in the Far Eastern Asia Region including Korea and Japan, Morphological Characteristics of B. Tabaci were also observed by the scanning electron microscope and described with the comparison to the other important whitefly pest, Trialeurodes vaporariorum (Westwood).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.5
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• pp.463-469
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• 1999

The potassium lithium niobate $K_3$$Li_2$$Nb_5$$O_{15}$ single crystals were growing in $K_x$$Li_{1-x}$$NbO_3$ (x = 0.4~0.6) chemical formular by the Czorchralski method. Crystal growth is studied in two orientations with growth along a-axis and c-axis. We have subjected this crystal to x-ray diffraction studies and found that they are single-crystalline and belong to tetragonal system with the lattice parameters a = b = 12.577 $\AA$ and c = 3.997$\AA$. The temperature dependence of dielectric constant was measured in the region of the phase transition. Curie temperature and diffuseness of phase transition are influenced by composition concentration. The composition and cation distribution of ferroelectric TB-type niobate crystals has a strong influence on the ferroelectric properties. Growth condition, optical transmittance, etching pattern and dielectric properties are presented and discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.8
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• pp.1076-1082
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• 2018

This paper describes interferometer direction finder which measures the angle of arrival based on calculation of the phase difference of received radio signal from different antennas. Modern Electronic Warfare direction finder uses digital phase difference measuring techniques which have less effect on temperature variation and better performance under low Signal to Noise Ratio environment. In this paper, we analyze acceptable phase difference error for requirement of system's direction finding accuracy and introduce digital phase difference calculation techniques. We have investigated quantitative analysis on phase difference calculation according to sample number, SNR, interference injection. Through the simulation, frequency domain measurement technique is better performance than the time domain one at the environment of low SNR and interference injection. Proposed method can be used to determine the performance of interferometer direction finder.

• Anxiety and mood
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• v.13 no.1
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• pp.46-52
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• 2017

Objective : The purpose of the present study was to examine the effectiveness of a school-based character education program on the character development of elementary school students. Methods : A total of 1,325 elementary school students participated in the study. Pre-post changes in eight character virtues (self-esteem, self-regulation, honesty, sincerity, communication & caring, citizenship, justice, responsibility/cooperation) and student satisfaction were assessed. A paired t-test was performed to determine the effects of the program. Results : Of the students who participated in the program, the 4th and 5th grade students showed significantly increased scores on all eight character virtues ; whereas, the 6th grade students showed significantly increased scores on five character virtues. Conclusion : Despite the differences in effect based on the grade levels, the study results supported the effectiveness of a school-based socio-emotional character education program. This study could provide a basis for future research on the development of effective character education programs.

• Journal of the Korean School Mathematics Society
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• v.15 no.4
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• pp.605-625
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• 2012

This study examined how 132 teachers of different grade levels incorporate the key competencies identified by Korea Institute for Curriculum and Evaluation into their mathematics teaching and how they perceive of its full potential of the competency-based learning and teaching in mathematics classroom. Survey and semi-structured interview methods were used to collect data for the study. It was found that in their instruction teachers emphasized competencies such as problem-solving, literacy, creativity, communication and information-processing skills in order. Inter-personal skills, self-management, citizenship, global understanding and career-development appeared to be challenging competencies for teachers to reflect in their instruction with the reasons such as no direct connections to mathematics and insufficient instruction. Findings of the study suggest that various instructional methods, development and dissemination of related curricula materials, change of evaluation method, and change teachers' perceptions may be needed for incorporating KICE's key competencies in K-12 mathematics education.

• The Journal of Natural Sciences
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• v.10 no.1
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• pp.73-80
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• 1998

This experiment was carried out to investigate the effect of runner development based on production period and to investigate the yield in different cropping type to nursery plant age. In runner development experiment, heating + lighting + $GA_3$ + cluster removal treatment increased the number of runners by 13.1 times higher in spring season than control(heating only) in overwintering mother-plant. Treatment of 20ppm $GA_3$ was the most effective for runner production in autumn. In nursery plant age experiment, 60 days old nursery plants produced more flower cluster than 40 days old ones. This result indicated that the yield potential was so low that overwintering runners would be adaptable for spring or summer cultivation.