• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2954-2972
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• 1998

It is expected that the transport of compressed video will become a significant part of total network traffic because of the widespread introduction of multimedial services such as VOD(video on demand). Accordingly, VBR(variable bit-rate) encoded video will be widely used, due to its advantages in statistical multiplexing gain and consistent vido quality. Since the transport of video traffic requires larger bandwidth than that of voice and data, the characterization of video source and traffic modeling is very important for the design of proper resource allocation scheme in ATM networks. Suitable statistical source models are also required to analyze performance metrics such as packet loss, delay and jitter. In this paper, we analyzed and described on the characterization and traffic modeling of MPEG video sources. The models are broadly classified into two categories; i.e., statistical models and deterministic models. In statistical models, the models are categorized into five groups: AR(autoregressive), Markov, composite Marko and AR, TES, and selfsimilar models. In deterministic models, the models are categorized into $({\sigma},\;{\rho}$, parameterized model, D-BIND, and Empirical Envelopes models. Each model was analyzed for its characteristics along with corresponding advantages and shortcomings, and we made comparisons on the complexity of each model.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.265-269
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• 2005

본 연구에서는 분포형 수문모형인 WEP 모형을 도시하천인 청계천 유역에 적용하여 하천 유출을 모의하였다. 하천-지하수 흐름 교환을 고려하여 건천화된 하천 유역의 갈수량을 모의하기 위해 하천 및 지하투수층의 매개변수 자료를 실측 자료로 구축하거나 실측 자료를 바탕으로 이를 보간하여 구축하였다. 모형의 적용 결과, 청계천 유역 상류 부관은 관측값과 비슷한 모의 양상을 보였으나 하류 부근은 모의 결과와 관측값이 상이하였는데, 이는 상류 부근은 도시화가 적게 진행된 반면, 하류 부근은 대부분 도시화되어 지하철, 합류식 하수관 등 하천-지하수의 흐름 교환을 차단하는 인공적인 요소가 많기 때문으로 판단된다. 도시하천 갈수량의 보다 정확한 모의를 위해서는 도시지역 인공적인 지하수 차단 요인에 대한 세밀한 모형화와 자료 구축이 요구된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2271-2282
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• 2006

This paper is concerned with simulation issues arising in the PDE-based image restoration such as the total variation minimization(TVM) and its generalizations. In particular, we study the issues of staircasing and excessive dissipation of TVM-like smoothing operators. A strategy of scaling the algebraic system and a non-convex minimization are considered respectively for anti-staircasing and anti-diffusion. Furthermore, we introduce a variable constraint parameter to better preserve image edges. The resulting algorithm has been numerically verified to be efficient and reliable in denoising. Various numerical results are shown to confirm the claim.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.131-136
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• 1993

일반적으로 공작기계 주축계에 대해서 요구되는 기본적인 항목들로는 고강성, 고감쇠, 고회전정밀도, 저발열, 장수명 등이 있다. 최근에는 이러한 기능들과 함께 가공능률과 가공정밀도의 향상을 도모하기 위해서 고속절삭을 실현햐ㄹ 수 있는 공작기계 주축계의 고속화, 즉 고속 주축계에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 고속주축계의 동특성을 체계적으로해석하기 위해서 주축회전수의 영향을 고려한 유한요소모델(finite element model)을 도입하였다. 특히 주축은 세장비가 비교적 자기 때문에 Timoshenko보 이론으로, 베어링은 유한한 폭을 가지고 있기 때문에 반경방향 외에도 모멘트방향의 강성 및 감쇠특성을 가지고 있는 것으로 모델화 하였다. 그리고 고속주축계의 설계조건들을 도출하기 위해서 동특성 해석결과들로 부터 고속주축계의 모드매개변수들인 고유진동수와 감쇠비에 대한 주축 회전수, 베어링의 지지특성, 베어 링의 간격, 주축재료의 내부감쇠율 등의 영향을 고찰하였다.

• The Journal of the Acoustical Society of Korea
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• v.5 no.3
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• pp.28-35
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• 1986

우리나라 음성의 유성음을 모음, 비음 및 유성화 자음으로 분류하는 알고리즘을 기술하였다. 먼 저 기존의 PITCH 검출 알고리즘에 의하여 음성을 유성음과 무성음으로 나눈 뒤, 단지 정규화된 1차 상 관계수, 영교차율, LOG 에너지 및 LPG 에너지의 골짜기 검출만을 이용하여, 유성음은 모음, 비음 및 유 성화자음으로 분류하고 무성음은 실제의 무성음과 묵음으로 분류하였다. 그리고 이렇게 분류된 모음에 대하여 단모음 인식을 행하였다. 단지 한 FRAME으로 모음을 대표하였기 때문에 메모리 크기와 인식 시간을 줄였다. 여기서 UP & DOWN 및 수정된 영교차율을 새로이 정의하여 적용한 결과 만족한 결과 를 얻을 수 있었다. LPC 매개변수 및 전력 스펙트럼도 단모음 인식의 FEATURE로 사용하였다. 그리고 각 FEATURE 의 성능을 비교하였다. 이들 FEATURE을 잘 조합하여 2단계 인식을 행한 결과 92%의 높은 인식율을 얻을 수 있었다.

• Korean Journal of Social Welfare Studies
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• v.45 no.3
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• pp.237-262
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• 2014

Little is known about the relationships among adolescents'academic stress, self-efficacy, and internalization externalization. Much less is known about whether there is gender differences in the relationships. This study aims to examine (1) the effects of academic stress on internalization externalization, (2) whether self-efficacy mediates the relationships between academic stress and internalization externalization, and (3) whether there is gender difference in the relationships. For these purposes, we used Structural Equation Modeling and multi group analysis involving 2,844 middle school students participated in the Korean Youth Panel Survey. The results are as follows. First, adolescent's academic stress affected internalization externalization. Second, self-efficacy mediated the relationship between academic stress and internalization externalization. Finally, the multiple group analysis results indicated that the path coefficient between academic stress and internalization of girls was significantly greater than that of boys. Based on these results, we discussed theoretical and practical implications and suggested directions for future research on academic stress coping processes among adolescents.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.6
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• pp.201-214
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• 2023

This study attempted to analyze the impact of individual entrepreneurial capabilities on entrepreneurial intention targeting small and medium-sized business employees, and sought to confirm the mediating effect of entrepreneurial efficacy and entrepreneurial mentoring between entrepreneurial capabilities and entrepreneurial intention. The sub-variables of entrepreneurship competency were analyzed separately into creativity, problem solving, communication, and marketing. 368 questionnaires collected from employees at small and medium-sized manufacturing companies located across the country were used for empirical analysis. A parallel dual mediation model with no causal relationship between parameters was used for empirical analysis using SPSS v26.0 and PROCESS macro v4.2. As a result of the analysis, first, among the start-up competencies, creativity, communication, and marketing were confirmed to have a significant positive (+) effect on start-up efficacy. Second, among the start-up competencies, creativity, communication, and marketing were tested to have a significant positive influence on start-up mentoring. Third, both startup efficacy and startup mentoring were found to have a significant positive influence on startup intention. Fourth, among start-up capabilities, creativity and marketing were confirmed to have a significant positive (+) effect on start-up intention. Fifth, startup efficacy and startup mentoring were found to have a mediating effect on startup intention except for problem solving among startup competencies. As a result, it was confirmed that in order to strengthen the intention to start a business among small and medium-sized business employees, start-up efficacy and start-up mentoring are important factors, and that marketing and creativity have an important influence among individual start-up capabilities, so education and prior preparation for these are necessary. As follow-up research, it will be necessary to apply multivariate models, analyze time series data, research considering external environmental factors, and test the difference between start-up capabilities and performance considering detailed population characteristics.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.433-440
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• 2015

This study was conducted to examine mediative effects of two factors, emotion control and thinking control, in the relationship between avoid fusion and attention. Participants (308 high school students) were asked to complete a questionnaire which contains items to measure some psychological properties such as emotion control (EC), thinking control (TC), avoidance avoid fusion (CF), conceration(Co) and learning attitude(LA). Structural equation model analysis showed that 8 of modified 9 paths were statistically significant; CF to Co and TC, TC to EC, Co, and LA, EC to Co and LA, and Co to LA. Limitations and suggestions were mentioned in the discussion.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.726-737
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• 2020

This study analyzed 4,284 elderly people aged 65 or older by SPSS 22.0 in the 7th data of 「2018 Korean Longitudinal Study of Ageing(KLoSA)」 to confirm the effect of the health-promoting behavior of the elderly on life satisfaction through cognitive function. The cognitive function level of the subjects was 13.8% doubtful about dementia, 23.8% cognitive decline, and 62.4% normal, and the satisfaction level of life was 59.304 points. The results of the study were as follows: First, the difference in cognitive function according to demographic characteristics was significant in gender, age, education, religion, and marriage factors. Second, the satisfaction of the elderly's life according to demographic characteristics was confirmed to have significant differences in gender, age, education, religion, and marriage factors. Third, the satisfaction of the elderly's life was significantly positive in drinking and regular exercise factors among independent variable the health-promoting behavior when cognitive function was mediated. On the other hand, The significant negative effect of the restriction of daily life activities was confirmed. In this way, the mediating effect of cognitive function was verified in the effect of the health-promoting behavior on the satisfaction of the elderly life.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.209-220
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• 2021

This study sought to examine the impact relationship of the mediated effects of organizational justice on the effects of workplace bullying on turnover intentions. The research hypothesis was verified using SPSS 24 and smartPLS 3 by analyzing 400 surveys of small and medium enterprise workers. Studies have shown that increasing bullying in the workplace also increases emotional depletion and turnover intentions. Emotional depletion has been shown to significantly mediate the impact relationship between workplace bullying and turnover intentions, and organizational justice has laid a theoretical foundation for significantly moderating the impact relationship between workplace bullying and emotional depletion. Therefore, it presented practical implications to increase competitiveness through the well-being and growth of individuals and businesses by increasing respect and sensitivity for workers through compulsory bullying prevention education and various programs. Future research requires research using various variables to prevent bullying.