• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.466-468
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• 2012

Amorphous InGaZnO (${\alpha}$-IGZO) thin-film transistors (TFTs) are are very promising due to their potential use in thin film electronics and display drivers [1]. However, the stability of AOS-TFTs under the various stresses has been issued for the practical AOSs applications [2]. Up to now, many researchers have studied to understand the sub-gap density of states (DOS) as the root cause of instability [3]. Nomura et al. reported that these deep defects are located in the surface layer of the ${\alpha}$-IGZO channel [4]. Also, Kim et al. reported that the interfacial traps can be affected by different RF-power during RF magnetron sputtering process [5]. It is well known that these trap states can influence on the performances and stabilities of ${\alpha}$-IGZO TFTs. Nevertheless, it has not been reported how these defect states are created during conventional RF magnetron sputtering. In general, during conventional RF magnetron sputtering process, negative oxygen ions (NOI) can be generated by electron attachment in oxygen atom near target surface and accelerated up to few hundreds eV by self-bias of RF magnetron sputter; the high energy bombardment of NOIs generates bulk defects in oxide thin films [6-10] and can change the defect states of ${\alpha}$-IGZO thin film. In this paper, we have confirmed that the NOIs accelerated by the self-bias were one of the dominant causes of instability in ${\alpha}$-IGZO TFTs when the channel layer was deposited by conventional RF magnetron sputtering system. Finally, we will introduce our novel technology named as Magnetic Field Shielded Sputtering (MFSS) process [9-10] to eliminate the NOI bombardment effects and present how much to be improved the instability of ${\alpha}$-IGZO TFTs by this new deposition method.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.239-242
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• 2001

본 논문에서는 self-bias 구조를 갖는 소 신호 증폭기에 대해 논의된다 주파수 영역은 ISM band (Industria1/Scientific/Medical band) 인 무선 랜 (WLL : Wireless Local Loop) 대역 5.8GHz 에서 설계하였다. 제시된 self-bias 구조는 단일 전원만을 사용한다는 장점을 가지고 있으며 입력 단에서 RFC (λ/4 전송선로)를 제거하고 매칭 회로에서 단락 스터브를 사용함으로 구조를 간단히 하였다. 이러한 bias조건에서 FET의 이득은 11dB이고 회로 설계 후 측정 결과는 입력 반사 손실 -16.455dB, 이득은 8.095dB이다. 이 소 신호 증폭기는 간단한 구조로 구현된 장점 뿐 만 아니라 무선 랜 분야에서도 충분히 응용 될 수 있으리라 기대된다.

• Korean Journal of Culture and Social Issue
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• v.29 no.4
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• pp.477-496
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• 2023

The purpose of this study is to examine the relationship between rejection sensitivity and reactive aggression among college students, as well as to determine the mediating effects of self-concept clarity and hostile attribution bias on the relationship between rejection sensitivity and reactive aggression. A self-report questionnaire was conducted online for the purpose of gathering data from university students aged 18 years and older. A total of 250 participants were included in the analysis. SPSS 27.0 was used for data analysis to check the basic statistics of the variables, frequency analysis, reliability analysis, and correlation analysis. In addition, the model fit was checked using Amos 21.0, and the bootstrapping method verified the significance of the indirect effect. The results of this study are as follows. The results of this study are as follows. First, rejection sensitivity positively affects reactive aggression through self-concept clarity. Second, rejection sensitivity increases the hostile attribution bias, leading to an increase in reactive aggression. Third, rejection sensitivity positively influences reactive aggression in an indirect way by sequentially affecting self-concept clarity and hostile attribution bias. These findings have implications as they identify psychological factors that affect reactive aggression in college students. This suggests the importance of utilizing psychological interventions to address reactive aggression associated with social problems, such as crime, and provides a foundation for both treatment and prevention. Finally, implications for further research and limitations of this study are suggested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.7
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• pp.1218-1222
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• 2008

We investigate the effect of rise time of a pulse bias voltage on atmospheric plasma generation. With the faster rise time of the pulse bias, the glow discharge appears to be more uniformly generated along the electrodes. I-V measurement confirms that higher loading power can be obtained using the faster rise time. A new understanding for atmospheric plasma generation at a micro-gap electrode is suggested.

• Journal of electromagnetic engineering and science
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• v.17 no.2
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• pp.105-107
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• 2017

The self-biasing circuit through a feedback resistor is applied to a gallium nitride (GaN) distributed power amplifier (PA) monolithic microwave circuit (MMIC). The self-biasing circuit is a useful scheme for biasing depletion-mode compound semiconductor devices with a negative gate bias voltage, and is widely used for common source amplifiers. However, the self-biasing circuit is rarely used for PAs, because the large DC power dissipation of the feedback resistor results in the degradation of output power and power efficiency. In this study, the feasibility of applying a self-biasing circuit through a feedback resistor to a GaN PA MMIC is examined by using the high operation voltage of GaN high-electron mobility transistors. The measured results of the proposed GaN PA are the average output power of 41.1 dBm and the average power added efficiency of 12.2% over the 6-16 GHz band.

• Journal of Korean Clinical Nursing Research
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• v.28 no.1
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• pp.23-33
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• 2022

Purpose: This study aimed to identify the relationships among disease severity, anxiety, depression, social support, unpleasant symptoms and self-care among patients with atrial fibrillation based on the unpleasant symptom theory, and to examine the mediating effects of unpleasant symptoms. Methods: A cross-sectional study was conducted. The participants were 216 patients with atrial fibrillation who were being followed up on an outpatient basis at a university hospital in Seoul. Data were collected from November 1, 2020 to June 30, 2021, using self-report questionnaires. Data were analyzed using IBM SPSS/WIN 27.0 and PROCESS macro with 95% bias-corrected bootstrap confidence interval(CI). Results: The average age of participants in this study was 66.0years. Disease severity (β=10.19, p<.001) and depression (β=1.53, p<.001) had significant positive relationships with unpleasant symptoms. Also, unpleasant symptoms (β=-0.03, p=.006) had a negative relationship with physical activity, which is a subscale of self- care. Social support (β=0.06, p<.001) was positively related with physical activity. Unpleasant symptoms showed a mediation effect in the relationship between disease severity and physical activity (Bias corrected bootstrap CI -0.65, -0.04). Depression had an indirect effect on physical activity that was mediated by unpleasant symptoms (Bias corrected bootstrap CI -0.11, -0.00). Conclusion: The findings of this study suggest that integrated strategies including physical, psychological, and social factors should be considered to promote self-care in patients with atrial fibrillation.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.5
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• pp.220-229
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• 2004

We have examined a technique of one-dimensional (1D) fluid modeling for radio-frequency Ar capacitively coupled plasmas (CCP) between unequal-sized powered and grounded electrodes. In order to simulate a practical CCP reactor configuration with a grounded side wall by the 1D model, it has been assumed that the discharge space has a conic frustum shape; the grounded electrode is larger than the powered one and the discharge space expands with the distance from the powered electrode. In this paper, we focus on how much a 1D model can approximate a 2D model and evaluate their comparisons. The plasma density calculated by the 1D model has been compared with that by a two-dimensional (2D) fluid model, and a qualitative agreement between them has been obtained. In addition, 1D and 2D calculation results for another reactor configuration with equal-sized electrodes have also been presented together for comparison. In the discussion, four CCP models, which are 1D and 2D models with symmetric and asymmetric geometries, are compared with each other and the DC self-bias voltage has been focused on as a characteristic property that reflects the unequal electrode surface areas. Reactor configuration and experimental parameters, which the self-bias depends on, have been investigated to develop the ID modeling for reactor geometry with unequal-sized electrodes.

• Women's Health Nursing
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• v.26 no.4
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• pp.274-284
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• 2020

Purpose: The purpose of this study was to investigate the effects and characteristics of health care programs for pregnant women with gestational diabetes mellitus (GDM) in Korea. Methods: This study was conducted according to the Cochrane Collaboration's systematic literature review handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline. We searched eight international and domestic electronic databases for relevant studies. Two reviewers independently selected the studies and extracted data. For each study, information on the research method, participants, characteristics of the program, and results were extracted using a previously established coding table. The National Evidence-based Healthcare Collaborating Agency's risk of bias assessment tool for non-randomized studies was used to assess the risk of bias of the included articles. A qualitative review of the selected studies was performed because the interventions differed considerably and the measured outcomes varied. Results: Out of 128 initially identified papers, seven were included in the final analysis. The risk of bias was evaluated as generally low. Health care programs for pregnant women with GDM showed positive effects on blood glucose control. Anxiety and depression were reduced, and self-management and self-care behavior, self-efficacy, and maternal identity improved. Conclusion: Our study provides clinical evidence for the effectiveness of health care programs for pregnant women with GDM, and its results can be used to support the development of health care programs for GDM. More well-designed research is needed on GDM, especially studies that deal with emotional stress and apply a family-oriented approach.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.15 no.2
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• pp.152-159
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• 2004

Objective : The present study investigated the interpretation bias and expectation and judgemental bias of performance in socially anxious children. Method : Children with high social anxiety (n=18) and low social anxiety (n=16) were recruited through self-report and peer nomination, Participants performed three tasks to assess for cognitive bias. The first task measured interpretation of ambiguous social situations. The second task measured expectations regarding performance in a three minute impromptu speech. The third task assessed for judgemental bias via comparison between post-speech self rating and observer rating. Result : Children with high social anxiety did not differ significantly from low social anxiety children on the dependent measures assessing bias in interpretation, expectation and judgement. However, a significant difference was found in the judges' rating of children's performances on the speech task, with high social anxiety children obtaining significantly lower scores compared to low social anxiety children. Conclusion : The role of cognitive biases in the development and maintenance of social anxiety in children was discussed.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.752-759
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• 2008

In this paper, we propose a high accurate geo-location system based on a single base station, where its location is obtained by Time-of-Arrival(ToA) and Direction-of-Arrival(DoA) of the radio signal. For estimating accurate ToA and DoA information, a MUltiple SIgnal Classification(MUSIC) is adopted. However, the estimation of ToA and DoA using MUSIC algorithm is a time-consuming process. The position tracking bias is occurred by the time delay caused by the estimation process. In order to mitigate the bias error, we propose the estimation method of the position tracking bias and compensate the location error produced by the time delay using the position tracking bias mitigation. For accurate self-localization of mobile robot, the Unscented Kalman Filter(UKF) with position tracking bias is applied. The simulation results show the efficiency and accuracy of the proposed geo-location system and the enhanced performance when the Unscented Kalman Filter is adopted for mobile robot application.