요인분석을 통한 중국인 대학원생의 한국어 발표 불안 탐색

ZHAO SHUJUN,CHEN YING 반교어문학회 2023 泮橋語文硏究 Vol.- No.64

The purpose of this study is to identify the patterns and factors of public speaking anxiety by Chinese graduate students. A survey was conducted with 239 Chinese graduate students studying in domestic universities. The results showed that Chinese graduate students had a relatively high level of public speaking anxiety, surpassing the median. Furthermore, the sub-factors of public speaking anxiety included perception and attitude towards public speaking, evaluation anxiety, preparation anxiety, mistake anxiety, competition anxiety, situational anxiety, and anxiety about presentation requirements. In terms of the differences in public speaking anxiety according to gender, it was found that factors such as perception and attitude towards presentations, evaluation anxiety, and competition anxiety were statistically significant, while the remaining factors were not. Regarding the differences in public speaking anxiety based on the academic program, it was found that factors such as perception and attitude towards presentations, preparation anxiety, and competition anxiety were statistically significant, while the remaining factors were not. Next, in terms of the differences in public speaking anxiety based on the topic exam grades, other factors than preparation anxiety and competition anxiety showed no statistically significant difference. Furthermore, in terms of the differences in public speaking anxiety based on the duration of Korean language learning, factors such as perception and attitude towards presentations, evaluation anxiety, preparation anxiety, and competition anxiety showed no statistically significant differences, while the remaining factors did not show any significant differences. Lastly, it was found that, apart from anxiety about public speaking’s requirements, all other factors had a statistically significant influence on the perception and attitude towards presentations. This study investigated aspects of public speaking anxiety among Korean language learners that have not been extensively researched in academia, using graduate students as the research subjects. These research findings are significant in providing theoretical information to suggest differentiated presentation education methods for future graduate students. 본 연구는 중국인 대학원생을 대상으로 발표 과정에서 경험하는 불안의 양상과 요인을 파악하는 데에 목적이 있다. 본 연구에서는 국내 재학 중인 중국인 대학원생 239명을 대상으로 설문조사를 실시하였다. 그 결과, 중국인 대학원생의 발표 불안은 중앙값을 상회하는 다소 높은 수준이었다. 또한 발표 불안의 하위요인은 발표에 대한 인식 및 태도, 발표에 대한 평가 불안, 발표 준비불안, 발표 실수 불안, 발표 경쟁 불안, 발표 상황 불안, 발표 요구 사항 불안으로 나타났다. 성별에 따른 발표 불안의 차이에서는 발표에 대한 인식 및 태도, 발표 평가 불안, 발표 경쟁 불안 요인 외에는 나머지 요인들은 통계적으로 유의미하지 않은 것으로 나타났다. 학위과정에 따른 발표 불안의 차이에서는 발표에 대한 인식 및 태도, 발표 준비 불안, 발표 경쟁 불안 요인 외에는 나머지요인들은 통계적으로 유의미하지 않은 것으로 나타났다. 그다음 토픽 시험 등급에 따른 발표 불안의 차이에서는 발표 준비 불안, 발표 경쟁 불안 요인 외에는 나머지 요인들은 통계적으로 유의미한 차이를 보이지 않았다. 또한 한국어학습 기간에 따른 한국어 발표 불안의 차이에서는 발표 인식 및 태도, 발표 평가 불안, 발표 준비 불안, 발표 경쟁 불안 요인 외에는 나머지 요인들은 통계적으로 유의미한 차이를 보이지 않았다. 마지막으로 발표 요구 사항 불안 요인외에는 나머지 요인들은 모두 발표 인식 및 태도에 유의미한 영향을 미치는 것으로 나타났다. 본 연구는 대학원생을 연구 대상으로 삼아 한국어 학습자의 발표 불안에 대해 학계에서 많이 연구되지 않았던 부분을 조사하였다. 이러한 연구 결과는 향후 대학원생을 위한 차별화된 발표 교육 방안을 제시하기 위해 이론적 정보를 제공하는 데에 의의가 있다.

NB-UVB Induces Melanocytic Differentiation of Human Hair Follicle Neural Crest Stem Cells

( Dake Dong ),( Shujun Chen ),( Cheng Feng ),( Huizi Xiong ),( Xiaowei Xu ) 대한피부과학회 2020 Annals of Dermatology Vol.32 No.4

Background: Phototherapy is an important method to treat vitiligo. However, it is unclear how phototherapy affects melanocyte precursors and skin neural crest stem cells. Objective: To investigate the underlying mechanisms of narrow- band ultraviolet B (NB-UVB) induced melanocyte lineage differentiated from human scalp-derived neural crest stem cells (HS-NCSCs). Methods: HS-NCSCs were expanded from scalp hair follicles. The c-Kit^-/CD57^- HS-NCSCs were isolated by cell sorting. Different doses of NB-UVB were used to irradiate these HS-NCSCs. Cell ultrastructure was examined by transmission electron microscope. Melanocyte marker expression was analyzed by Quantitative RT-PCR and Western blot. Cell proliferation and migration were also evaluated. Results: The c-Kit^-/CD57^- HS-NCSCs expressed embryonic NCSC biomarkers. NB-UVB at a dose of 100 mJ of NB-UVB had little effect on the cell proliferation of differentiated melanocytes from c-Kit^-/CD57^- HS-NCSCs, while 700 mJ inhibited cell proliferation significantly. The dendritic processes of differentiated melanocytes increased after radiation. The tyrosinase and Melanocortin 1 receptor (Mc1R) expression of differentiated melanocytes increased after NB-UVB exposure. The effect of NB-UVB on tyrosinase expression was modulated by signaling inhibitors H89 and PD98059 as well as Mc1R level in the cells. The migration ability of differentiated melanocytes was enhanced under 100 mJ exposure. Conclusion: These data demonstrate that NB-UVB facilitates melanocytic differentiation of the HSNCSCs and enhances migration of these cells. Mc1R and cAMP pathway play a critical role in NB-UVB induced melanocytic differentiation. (Ann Dermatol 32(4) 289∼297, 2020)

Comparison of dexmedetomidine and opioids as local anesthetic adjuvants in patient controlled epidural analgesia: a meta-analysis

Gao Yafen,Chen Zhixian,Huang Yu,Sun Shujun,Yang Dong 대한마취통증의학회 2024 Korean Journal of Anesthesiology Vol.77 No.1

Background: Data on the efficacy and incidence of adverse effects associated with dexmedetomidine (DEX) as a local anesthetic adjuvant for patient-controlled epidural analgesia (PCEA) are inconclusive. This meta-analysis assessed the efficacy and risks of DEX for PCEA using opioids as a reference.Methods: Two researchers independently searched PubMed, Embase, Cochrane Library, and China Biology Medicine for randomized controlled trials comparing DEX and opioids as local anesthetic adjuvants in PCEA.Results: In total, 636 patients from seven studies were included in this meta-analysis. Postoperative patients who received DEX had lower visual analog scale (VAS) scores than those who received opioids at 4–8 h (mean difference [MD]: 0.61, 95% CI [0.45, 0.76], P < 0.001, I2 = 0%), 12 h (MD: 0.85, 95% CI [0.61, 1.09], P < 0.001, I2 = 0%), 24 h (MD: 0.59, 95% CI [0.06, 1.12], P = 0.030, I2 = 82%), and 48 h (MD: 0.54, 95% CI [0.05, 1.02], P = 0.030, I2 = 91%). Additionally, patients who received DEX had a lower incidence of itching (odds ratio [OR]: 2.86, 95% CI [1.18, 6.95], P = 0.020, I2 = 0%) and nausea and vomiting (OR: 6.83, 95% CI [3.63, 12.84], P < 0.001, I2 = 24%). In labor analgesia, no significant differences in neonatal (pH and PaO2 of cord blood, fetal heart rate) or maternal outcomes (duration of labor stage, mode of delivery) were found between the DEX and opioid groups.Conclusions: Compared with opioids, using DEX as a local anesthetic adjuvant in PCEA improved postoperative analgesia and reduced the incidence of itching and nausea and vomiting without increasing the incidence of adverse events.

Increased Circulating CXCL10 in Non-Segmental Vitiligo Concomitant with Autoimmune Thyroid Disease and Alopecia Areata

( Li Zhang ),( Xinya Xu ),( Shujun Chen ),( Yuli Kang ),( Xiuxiu Wang ),( Chengfeng Zhang ),( Leihong Xiang ) 대한피부과학회 2019 Annals of Dermatology Vol.31 No.4

Background: Vitiligo is a common acquired pigmentary disease caused by destruction of epidermal melanocytes in underlying autoimmune response. Few studies have been focused on the role of chemokines in non-segmental vitiligo (NSV) concomitant with autoimmune thyroid disease (AITD) and alopecia areata (AA). Objective: The aim of this study was to determine the best serum biomarker for predictive role in the progression of vitiligo and to evaluate the influence of AA and/or AITD on vitiligo by using the biomarker. Methods: This prospective cohort study recruited 45 NSV patients: 14 without either AITD or AA, 12 with AITD, 11 with AA, and 8 with both AITD and AA. Serum levels of CXCL1, CXCL8, CXCL9, CXCL10, CXCL12, CXCL13, and CXCL16 were analyzed by ELISA. CXCR3 mRNA expression was detected on PBMCs by RT-PCR. Improvement was evaluated using repigmentation scales. Results: Serum CXCL10 levels, along with the expression of CXCR3 mRNA were higher in NSV patients with AITD or AA alone than in those without AITD or AA. Moreover, serum CXCL10 levels, along with the expression of CXCR3 mRNA were higher in NSV patients with both AITD and AA than in those with AITD or AA alone. Poorer repigmentation was observed in NSV patients with both AA and AITD than in those with AA or AITD alone. Conclusion: CXCL10 could be a biomarker to predict the progression of NSV. Dermatologists should pay much attention to those NSV patients concomitant with AITD and/or AA, for comorbidity might lead to more active autoimmune reaction. (Ann Dermatol 31(4) 393∼402, 2019)

Research on Reliability of Hadoop Distributed File System

Daming Hu,Deyun Chen,Shuhui Lou,Shujun Pei 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.11

Research on Hadoop Identity Authentication Based on Improved Kerberos Protocol

Daming Hu, Deyun Chen,Yuanxu Zhang,Shujun Pei 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.11

This paper researches the authentication mechanism of Kerberos protocol under HDFS, and points out the problems that identity authentication mechanism of Kerberos protocol faced in HDFS cluster environment: time synchronization, KDC security, dictionary attacks and denial mechanism. Aiming at these security problems, firstly, this paper provides an overview of the authentication process of the current Kerberos protocol under HDFS cluster environment; secondly, it modifies Kerberos protocol by using public key encryption and data signature mechanism; lastly, it provides the authentication process of improved Kerberos protocol in HDFS environment. Comprehensive analysis shows that both safety and time efficiency of the improved Kerberos protocol are improved compared with the existing identity authentication mechanism. It provides a more reliable and efficient identity authentication solution for HDFS cluster.

The influence of kinematics of blades on the flow structure in deep dynamic stall

Gul Chang,Hamid Reza Karbasian,Shujun Zhang,Yao Yan,Binqi Chen,Kyung Chun Kim 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

This study considers the effect of kinematics on the aerodynamic loads and flow structure around moving blades of micro air vehicles (MAVs) in deep dynamic stall. The transversal (pure heaving) and rotational (pure pitching) motions are considered distinctly to investigate the dynamic stall. An equivalent effective angle of the attack profile is given to both motions. This method helps to figure out the influence of kinematics on flow structures when all boundary conditions and effective angles of attack profiles are the same. An experiment is conducted in fully turbulent flow at Re = 1.5×10 4 to avoid any transition regime in the boundary layer, and make the results relatively independent of the flow characteristics. A NACA 0012 airfoil is chosen at high reduced frequencies (k = 0.25 and 0.375) and high angles of attack to reach deep dynamic stall conditions. Additionally, time-resolved particle image velocimetry (PIV) and post-processing are used to compute the aerodynamic loads using a control-volume approach. The flow field is also reconstructed using proper orthogonal decomposition (POD) to separate the flow structures in different modes. It is shown that the kinematics can significantly influence the flow structure and aerodynamic loads. In the pre-stall region, the pure pitching motion usually produces higher lift force, while the pure heaving motion has a higher lift peak. However, in the post-stall region, the pure heaving motion usually has higher lift than the pure pitching motion. The pure heaving motion produced lower drag force than the pure pitching motion. For pure heaving motion, the POD analysis reveals there is a high-energy mode in the flow structure that helps to make the vortices more stable compared to pure pitching motion. Furthermore, the pure heaving motion adds extra kinetic energy to the boundary layer, which decelerates the reversal flow and the transfer of the separation point on suction side of the airfoil.