• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.90-98
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• 2002

To increase system capacity in WCDMA receiver, the coherent detection is an essential technology for recovering transmitted symbols correctly. For coherent detection, an accurate and fast channel estimation is required. In next generation mobile communication system, high frequency carriers are used, and high data rate services are provided for subscribers having high mobility. In this communication environment, however, the rapidly-changing doppler frequency degrades the quality of the transmitted signal a lot. In WCDMA system, the channel estimation is conducted using pilot channel and/or pilot symbols which are known to both transmitter and receiver. Some existing channel estimation algorithms utilize these information quite well, but the performance of channel estimation gets very poor in a complicated fading channel distorted by the doppler effect. In this paper, we propose a new channel estimation algorithm combining an early-late doppler compensator so that the doppler effect and the fading characteristics are compensated at the same time. By computer simulation, the proposed algorithm proved to be a much more efficient channel estimation method in the fast fading channel, even at reasonably low Eb/No.

• Korean Journal of Childcare and Education
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• v.8 no.4
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• pp.33-51
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• 2012

The purpose of this study is to investigate the effect of social support and self-efficacy for parenting task on parent involvement of early childhood education. Subjects were 181 mothers with children ranging in age from three to five years old. Instruments used in this study were: 1) Self-efficacy for parenting task index(Colemen, Karraker, 2000), 2) Social support(Shin, 1997 ; Lee, 2006) and 3) Parent involvement(Conduct Problem Prevention Research Group(CPPRG), 1995; 2002). Data were analyzed using Pearson's correlation and hierarchical multiple regression analysis. Results of this study show that self-efficacy for parenting related to children's achievement and recreation, social support from the husband were positively correlated to the parent involvement of early childhood education. Also, mothers' self-efficacy for parenting task mediated between social support and parent involvement of early childhood education.

• Korean Journal of Medicinal Crop Science
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• v.23 no.5
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• pp.395-399
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• 2015

Background : This study examined the effect of harvesting time on the growth, yield characteristics, and major beneficial components in Salvia miltiorrhiza. Methods and Results : Although plant height, stem diameter and branch length were not affected by harvesting time, the number of stems was highest when harvested in mid October. There were no differences in root length and thickness, however, the rhizome was thicker when it was harvested at the end of October or early November than when it was harvested in early and mid October. The dried root weight also showed a similar pattern. However, there was a statistically significant increase to 408 kg (16%) in the rhizome weight when in late October and a rise to 455 kg (29%) when harvested in early November. Harvest time had little effect on the content of the major component of S. miltiorrhiza. For example, salvianolic acid content rose from 9.42 to 9.64% with later harvest times, and tanshinone ${\prod}A$ content was tended to be slightly more increased in mid October which S. miltiorrhiza has 0.22% tanshinon ${\prod}A$ than in early October. Conclusions : According to these results, the optimum harvest time for S. miltiorrhiza is early November when plant or major component yields are hightest. There were no significant harvest time effects on the major beneficial components.

• Journal of the Korean Home Economics Association
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• v.39 no.5
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• pp.107-121
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• 2001

The purpose of this study was to develop a sexuality education program for early adolescents. The overall goals of the program were to not only increase knowledge and skirts, but also to improve the awareness of healthy sex in order to promote premarital abstinence, parent-teen communication and parental awareness of the importance of parental roles and responsibilities in prevention of sexual problems of the early adolescent. The program consisted of six sessions: puberty changes during adolescence, the meaning of sexuality, sexual drives in dating relationships, understanding of the risks associated with early sexual involvement and support for postponing sexual activities, managing and avoiding sexually risky situations, the importance of communications with parents about issues related to sexuality. The program evaluation had three steps: pre-test, immediate post-test and two month follow-up post test. The results showed that the program had a significantly positive effect on the improvement of adolescent's knowledge about sex, and attitudes and behaviors toward sex, particularly in the immediate post-test. At the two month follow-up assessment, the effect of the program still remained strong, though there was a sight and partial reduction which was not statistically significant. Most of the program participants expressed a high level of satisfaction with the program. Parental involvement appeared to be effective as well. Recommendations for further study include: to re-evaluate the curriculum for various other participants. In addition, further study which would compare post-test results of these participants with a comparison group of peers who did not receive the program would be valuable. The author believes that the program can be used in implementing specific subjects (sessions) in new settings, as well as implementing the entire package of the program.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.112-119
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• 2022

Recently, as carbon neutrality has been important factor in the construction industry, many studies have been conducted on the high-volume fly ash concrete. High volume fly ash concrete(HVFC) is usually made by replacing more than 50% of cement with fly ash. However, HVFC has a disadvantage of low compressive strength in early age. To overcome this shortcoming of HVFC, improve this, interest in techonolgy using nanomaterials is increasing. Nano silica is expected to improve the early age strength of HVFC as a pozzolanic material. This study investigated the effect of nano silica on the early hydration reaction and microstructure of HVFC. The early hydration reaction of HFVC was analyzed through setting time, isothermal calorimeter, compressive strength and thermal weight analysis. In addition, the microstructure of HVFC was measured by mercury intrusion porosimetry. From the test results, it was confirmed that nano silica increased the early age strength and improve the microstructure of HVFC.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.242-252
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• 2022

Soybeans have various applications, and are a major source of proteins, carbohydrates, and fats. As climate warming has accelerated in recent years, this study was conducted to analyze the effect of different sowing periods on component changes in protein, amino acid, and antioxidant contents of various soybean varieties. The isoflavone content of soybeans that were sown early did not differ with the sowing period. Based on the results, only the total isoflavone content was confirmed in functional soybean cultivars such as Cheongja-5, which had blue-colored seeds; Pungsan and Sowon, which used soybean sprouts; and Jinyang, which lacked a fishy smell. There was no significant difference in the changes in protein and amino acid content in soybean cultivars with respect to the sowing time. The protein and amino acid contents in early-sown soybeans tended to be lower than that in timely sown soybeans. In most varieties, the content of proline was the highest in early-sown soybeans, confirming the presence of stress due to early sowing.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.429-430
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• 2014

• Cement Symposium
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• no.28
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• pp.88-96
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• 2001

• East Asian Journal of Business Economics (EAJBE)
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• v.10 no.3
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• pp.27-40
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• 2022

Purpose - The purpose of this study is to test the impact of job crafting on in/extra-role performance in Chinese context. In addition, it intends to verify the mediating effect of work engagement on the relationship between job crafting and in/extra-role performance. Research design, data, and methodology - Survey data were collected from employees of the companies in Hebei, China, for about two months, from early January 2022 to early March 2022. A total of 300 copies were distributed, and 240 copies were collected (80%), of which 222 copies were used for the final analysis. Data were analyzed for statistical tests of the measurement model and hypotheses using IBM SPSS Statistics 25 and Amos 25. Result - The analysis results are as follows. First, job crafting has a direct effect on work engagement. Second, work engagement increased employees' in/extra-role performance. Third, the mediating effect of work engagement was verified in the relationship between job crafting and employees' in/extra-role performance. Conclusion - This study expands the job demand-resource model by revealing the effect of job crafting, which changes the job given to oneself, on in/extra-role performance. In addition, this study investigated the impact of work engagement on the relationship between job crafting and in/extra-role performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.38-52
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• 2018

This study examined the effect sizes of psychological burnout-related factors on the psychological burnout of early childhood teachers by applying meta - analysis focusing on master 's theses, doctoral dissertations and journals that have been published in Korea for the past 20 years. The results of the analysis are as follows. First, the total effect size, the factor group, the sub-factor, and the positive and negative effect factors of the inducing and inhibiting factors showed a significant effect size. Second, in terms of inducing factors, the task problem group showed a larger effect size than the negative relationship group. Third, among the lower factor of the negative relationship group, all the sub factors excluding the negative relationship with the director, effect size showed a medium effect size. Fourth, task stress showed the greatest effect size among the sub factors of the task factor group, followed by role conflict, task overload, and role ambiguity. Fifth, resilience showed the greatest effect size among the inhibition factors, followed by organizational support factor, teacher efficacy factor, social support factor, and emotional factor. Sixth, all sub factors of the emotional labor factor group, organizational support factor of the organizational support factor group, general teacher efficacy factor of the teacher efficacy factor group, and all sub factors of social support factor Medium effect size. In addition, the lower factor of all the other factors showed a large effect size. Seventh, of the effect factors, job satisfaction factor, depression factor, and turnover intention factor all showed a large effect size.