• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2120-2133
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• 2013

In this paper, we address the problem of linear minimum mean-squared error (MMSE) transmitter design for the cognitive radio (CR) multi-user multiple-input single-output (MU-MISO) broadcasting channel (BC), where the cognitive users are subject to not only a sum power constraint, but also a interference power constraint. Evidently, this multi-constraint problem renders it difficult to solve. To overcome this difficulty, we firstly transform it into its equivalent formulation with a single constraint. Then by utilizing BC-MAC duality, the problem of BC transmitter design can be solved by focusing on a dual MAC problem, which is easier to deal with due to its convexity property. Finally we propose an efficient two-level iterative algorithm to search the optimal solution. Our simulation results are provided to corroborate the effectiveness of the proposed algorithm and show that this proposed CR MMSE-based scheme achieves a suboptimal sum-rate performance compared to the optimal DPC-based algorithm with less computational complexity.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권4호
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• pp.332-339
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• 2014

Face classification has wide applications in security and surveillance. However, this technique presents various challenges caused by pose, illumination, and expression changes. Face recognition with long-distance images involves additional challenges, owing to focusing problems and motion blurring. Multiple frames under varying spatial or temporal settings can acquire additional information, which can be used to achieve improved classification performance. This study investigates the effectiveness of multi-frame decision-level fusion with photon-counting linear discriminant analysis. Multiple frames generate multiple scores for each class. The fusion process comprises three stages: score normalization, score validation, and score combination. Candidate scores are selected during the score validation process, after the scores are normalized. The score validation process removes bad scores that can degrade the final output. The selected candidate scores are combined using one of the following fusion rules: maximum, averaging, and majority voting. Degraded facial images are employed to demonstrate the robustness of multi-frame decision-level fusion in harsh environments. Out-of-focus and motion blurring point-spread functions are applied to the test images, to simulate long-distance acquisition. Experimental results with three facial data sets indicate the efficiency of the proposed decision-level fusion scheme.

• 한국의류학회지
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• 제45권5호
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• pp.804-824
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• 2021

This study qualitatively explored the case of users utilizing multiple accounts on one social network service to create their own multiple spaces and different personas. The purpose of the study was to understand the behavior of people who use multiple accounts to express their identity online using Carl Jung's personality theory. We used in-depth interviews and the Zaltman metaphor elicitation technique (ZMET), targeting 19 people in their 20s and 30s who use more than one personal account on Instagram. Creating a shared consensus map using the configuration concept of ZMET derived six personas in relation to Instagram accounts. The motivations for the respondents' self-presentation associated with their personas and self-presentation types shown on Instagram were analyzed in terms of persona and fashion and subdivided into five dimensions: relationship management strategic presentation, self-monitoring presentation, competence demonstration presentation, anonymous presentation, and persona-centered presentation. Each respondent's persona and self-presentation formed by the Instagram account was analyzed.

• ETRI Journal
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• 제43권2호
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• pp.221-231
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• 2021

To resolve energy depletion issues in massive Internet of Things sensor networks, we developed a set of distributed energy beamforming methods with one-bit feedback and clustering for multi-node wireless energy transfer, where multiple singleantenna distributed energy transmitters (Txs) transfer their energy to multiple nodes wirelessly. Unlike previous works focusing on distributed information beamforming using a single energy receiver (Rx) node, we developed a distributed energy beamforming method for multiple Rx nodes. Additionally, we propose two clustering methods in which each Tx node chooses a suitable Rx node. Furthermore, we propose a fast distributed beamforming method based on Tx sub-clustering. Through computer simulations, we demonstrate that the proposed distributed beamforming method makes it possible to transfer wireless energy to massive numbers of sensors effectively and rapidly with small implementation complexity. We also analyze the energy harvesting outage probability of the proposed beamforming method, which provides insights into the design of wireless energy transfer networks with distributed beamforming.

• Korean Journal of Radiology
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• 제24권12호
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• pp.1260-1283
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• 2023

Magnetic resonance imaging (MRI) has been extensively applied in the study of multiple sclerosis (MS), substantially contributing to diagnosis, differential diagnosis, and disease monitoring. MRI studies have significantly contributed to the understanding of MS through the characterization of typical radiological features and their clinical or prognostic implications using conventional MRI pulse sequences and further with the application of advanced imaging techniques sensitive to microstructural damage. Interpretation of results has often been validated by MRI-pathology studies. However, the application of MRI techniques in the study of neuromyelitis optica spectrum disorders (NMOSD) remains an emerging field, and MRI studies have focused on radiological correlates of NMOSD and its pathophysiology to aid in diagnosis, improve monitoring, and identify relevant prognostic factors. In this review, we discuss the main contributions of MRI to the understanding of MS and NMOSD, focusing on the most novel discoveries to clarify differences in the pathophysiology of focal inflammation initiation and perpetuation, involvement of normal-appearing tissue, potential entry routes of pathogenic elements into the CNS, and existence of primary or secondary mechanisms of neurodegeneration.

• 디지털융복합연구
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• 제19권12호
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• pp.661-673
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• 2021

본 연구는 관상동맥중재술을 받은 남성의 건강행위 이행에 미치는 영향을 경과기간을 중심으로 파악하기 위한 서술적 상관관계 연구이다. 연구 대상자는 일개 대학병원에서 관상동맥중재술을 받은 남성 249명이며, 2017년 9월 1일부터 2018년 4월 30일까지 자료수집이 이루어졌다. 자료는 Stepwise multiple regression을 사용하여 분석하였다. 연구결과 건강행위 이행에 영향을 미치는 요인은 자기조절 중 자율적 동기(β=.35, p<.001), 교육요구도 중 위험요소(β=-.26, p<.001), 질병의 경과기간(β=.19, p<.001), 결혼 여부(β=.15, p=.001), 최종 학력(β=-.12, p=.035)이며, 총 설명력은 29.1%였다. 관상동맥 중재술을 받은 남성 환자의 건강행위 이행을 높이기 위해서는 중증도가 높고 경과시간이 1년 미만인 대상자의 자율적 동기를 강화할 수 있는 프로그램 개발이 필요하다.

• 근관절건강학회지
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• 제25권1호
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• pp.39-49
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• 2018

Purpose: The purpose of this study was to investigate the effect of technostress on intent-to-persist focusing on the stress coping in nursing college students. Methods: A cross-sectional descriptive design was conducted with a survey of 153 nursing college students attending a university. Data were collected using self-administered questionnaires. For data analysis, descriptive statistics, t-test, one-way ANOVA, Pearson's correlation coefficients, and multiple regression, hierarchical analysis, and sobel test were performed using SPSS/WIN 23.0 for Windows. Results: The factor mediating technostress and intent-to-persist in nursing college student was emotion-focused coping behavior. Moreover, this mediating factor had a complete mediating effect between technostress and intent-to-persist in nursing college students. Conclusion: Based on this result, it will be necessary to develop educational strategies about smart device use and environmental supports that help them communicate about problems.

• Human Ecology Research
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• 제52권4호
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• pp.395-403
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• 2014

The purpose of this study was to analyze the effects of children's self-esteem on their school adjustment, focusing on the mediation of peer attachment. A total of 2,200 3rd grade children from the third Korea Child-Adolescent Panel Survey participated in this study. The instruments used in this study were the Self-esteem Scale, Peer Attachment Scale, and School Adjustment Scale. The collected data were analyzed by using a Student's t -test, Pearson's partial correlation, simple regression, and hierarchical multiple regression with SPSS ver. 16.0 software. The main results of this study are as follows: first, the boys had higher self-esteem, peer attachment, and school adjustment scores than the girls. Second, there was a significant positive correlation between children's self-esteem and peer attachment as well as a significant positive correlation between children's self-esteem and school adjustment. Further, there was a significant positive correlation between children's peer attachment and school adjustment. Finally, children's self-esteem exerted positive effects on their peer attachment, and children's peer attachment had a positive influence on their school adjustment. The effect of children's self-esteem on their school adjustment was partially mediated by their peer attachment. These findings provide preliminary evidence that the relationships between children's self-esteem and school adjustment may be mediated by their peer attachment.

• 대한간호학회지
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• 제37권6호
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• pp.863-871
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• 2007

Purpose: The purpose of this study was to investigate the factors influencing nurses' clinical decision making focusing on critical thinking disposition. Methods: The subjects of this study consisted of 505 nurses working at one of the general hospitals located in Seoul. Data was collected by a self-administered questionnaire between December 2006 and January 2007. Data was analyzed by one way ANOVA, Pearson correlation coefficients, and stepwise multiple regression using SPSS Win 14.0. Results: The mean scores of critical thinking disposition and clinical decision making were 99.10 and 134.32 respectively. Clinical decision making scores were significantly higher in groups under continuing education, with a master or higher degree, with clinical experience more than 5 years, or with experts. Critical thinking disposition and its subscales have a significant correlation with clinical decision making. Intellectual eagerness/curiosity, prudence, clinical experience, intellectual honesty, self-confidence, and healthy skepticism were important factors influencing clinical decision making(adjusted $R^2=33%$). Conclusion: Results of this study suggest that various strategies such as retaining experienced nurses, encouraging them to continue with education and enhancing critical thinking disposition are warranted for development of clinical decision making.

• Human Ecology Research
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• 제52권5호
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• pp.541-549
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• 2014

The purpose of this study was to analyze the effects of preschool children's behavioral and emotional regulation on their peer play behavior, focusing on gender differences. A total of 214 4- and 5-year-old children attending a child care center in South Korea participated in this study. The instruments used in this study were the Child Behavior Rating Scale, Emotion Regulation Checklist, and Penn Interactive Peer Play Scale. The collected data were analyzed using a Student's t -test, Pearson's partial correlation, and multiple regressions with the SPSS software ver. 16.0. The main results of this study are as follows: first, there was a significant gender difference in preschool children's behavioral regulation, emotional control, play interaction, and play disruption. However, there was no gender difference in preschool children's play disconnection. Second, preschool children's emotional control and behavioral regulation had positive effects on their play interaction irrespective of gender. Third, preschool children's emotional instability and emotional control had a positive influence on their play disruption irrespective of gender. Finally, the factors of behavioral regulation and emotional instability significantly predicted the boys' play disconnection, while for the girls, the significant predictor was emotional control. Further, implications for the use of early intervention targeting specific behavioral and emotional regulation problems have been discussed.