• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.95-103
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• 2020

The aim of this study was to confirm the association between obesity and periodontitis in adults and identify the convergence relationship between periodontal disease and health-related behavior at each stage of obesity among 10,058 adults aged 30-79 years from the 7th National Health and Nutrition Survey data. We performed chi-square tests and multivariate logistic regression analyses, adjusting for demographic characteristics and health status. We found that the higher the obesity stage, the higher the risk of periodontitis. Smoking, not using oral care products, and not attending dental check-ups were associated with periodontitis. In addition, we found a difference in influence factors according to the stage of obesity. Increase in obesity stage is a negative influence on the prevalence of periodontitis. Hence, an oral health program should be applied to the obesity management process.

• 한국해양학회지
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• v.29 no.4
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• pp.392-401
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• 1994

We examined the temporal characteristics of the oceanic eddy diffusion at 5 coastal regions of Korea by measuring the separation distances of multiple drifters released simultaneously at the same by the GPS and Decca transponder system. The observed variance of separation distance, for the time scales from minutes to hours, is proportional to t/SUP m/ with scaling exponent m between 1.2 and 2.0. The observed Lagrangian trajectories of drifters show fractal characteristics instead of random walk or Brown motion. As an effort toward a development of a realistic model of the oceanic eddy diffusion, we simulated the Lagrangian trajectories of drifters by fractional Brown motion (FBM) model. The observed variances of drifter separations can be generated by the FBM process provided the Hurst exponent is the same as the observed one. We further showed that the observed power law in the variance of drifter separations cannot be simulated with an ordinary Brown motion or random walk process.

• Culinary science and hospitality research
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• v.19 no.5
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• pp.11-22
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• 2013

This study aimed to identify the relationships between the quality and image of school meal service and satisfaction perceived from high school students and to access the moderating effect of its distribution types. For the empirical analysis, this study used SPSS 18.0 and AMOS 18.0 and conducted frequency analysis, reliability analysis, exploratory and confirmatory factor analysis, path analysis and chi-square difference test. As a result of the analyses, the validity and reliability were identified showing over 0.4 factor loading value, ${\chi}^2$=258.831, d.f.=98, RMR=0.059, GFI=.822, AGFI=.776, NFI=0.908, IFI=0.941, CFI=0.940. The results of the structural equation modeling analysis are as follows: first, the quality of school meal service had a significant influence on its image; next, the image of school meal service had a significant influence on satisfaction with the service; last, there is a significant moderating effect of distribution types in the relationship between the image of school meal service and satisfaction with the service.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.396-401
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• 2019

A virtual rigid is modeled as the parallel structure of a virtual spring and a virtual damper. The reflective force from the virtual model is designed to be as large as possible to improve the realism of the virtual environment while maintaining the stable interaction. So, it is important to analyze the stability boundary of the virtual spring and damper. In the previous researches, the stability boundary is analyzed based on the zero-order-hold (ZOH) method, but it is analyzed based on the first-order-hold (FOH) method and the virtual damper in the paper. The boundary value of the stable virtual damper is inverse proportional to the sampling time and the maximum value of stable virtual stiffness is inverse proportional to the square of the sampling time. And the maximum value in the FOH method is increased to 110% of the value in the ZOH method. If the virtual damper is smaller than about 50% of the boundary value of the virtual damper in the FOH method, the stable virtual stiffness in the FOH method is several times larger than that in the ZOH method.

• Journal of Cadastre & Land InformatiX
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• v.49 no.1
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• pp.5-15
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• 2019

This study is to review methodological limitations of previous studies, propose Tobit Model as an analysis model. We model used annual rent-free as dependent variable and considering to contract characteristics and building characteristics as independent variable. We model was consisted to the three model as follow: Basic model, Time control model, Quadratic model. As a result of the analysis, existing variables revealed through previous studies such as contract period, contract area, total floor area, and building age were all statistically significant. These results were robust when considering time effects. Also, floor area and annual rent-free was quadratic relationship by inverse U shape. This result provide to methodological contribution for related research. Also, provide to more accurate information for participants in seoul office market.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1234-1239
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• 2019

This paper proposes a method for measuring fine dust concentration through digital processing of images captured by only existing CCTVs without additional equipment. This image processing algorithm consists of noise reduction, edge sharpening, ROI setting, edge strength calculation, and correction through HSV conversion. This algorithm is implemented using the C ++ OpenCV library. The algorithm was applied to CCTV images captured over a month. The edge strength values calculated for the ROI region are found to be closely related to the fine dust concentration data. To infer the correlation between the two types fo data, a trend line in the form of a power equation is established using MATLAB. The number of data points deviating from the trend line accounts for around 12.5%. Therefore, the overall accuracy is about 87.5%.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.49-49
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• 2020

하천 보 상류영역에서 발생하는 박리 흐름을 분석하기 위해 실험수로에 하천보 모형을 설치하고, 보 주변에서 발생하는 흐름 구조를 입자 영상 유속계(PIV)로 이용하여 정밀하게 측정하였다. 본 연구에 사용된 보는 하천 설계기준을 따른, 전방 수직벽과 하류 경사램프가 있는 유한한 마루 길이 보이다. 실험 조건은 보 상·하류부 수심으로 인한 4가지 흐름(Hydraulic jump, Plunging jet, Surface wave, Surface jet)을 기반으로 설정하여 수리조건에 따른 유속 특성을 규명하였다. 실험에서 측정한 수직-수평방향 평균 유속·유선도를 분석한 결과, 보 전방의 하부에서 재순환 흐름이 관측되었고, 역방향 흐름도 이 지역에서 발견되었다. 유속 편차의 제곱 평균(Root Mean Square) 흐름장에서 보 전방과 재순환 흐름 영역에 불안전한 흐름이 강하게 발견되었다. 역방향 흐름은 박리 흐름에서 발견되는 주요 특성으로, 역방향 흐름의 전체 면적을 매 관측마다 측정하여 이를 분석한 결과, 재순환 흐름의 면적은 오른쪽으로 기울어진 분포를 가지고, 항상 0보다 큰 값을 가지는 것으로 나타났다. 재순환 면적에 따른 흐름 특성은 역방향 흐름 면적에 대한 조건부 평균을 이용하여 파악했는데, 조건부 평균의 구간은 재순환 흐름의 중심에서 지배적인 주기값을 이용했다. 역방향 흐름이 작은 영역에선, 보 상류의 흐름이 재순환 흐름으로 말려들어가는 열린 박리흐름이 나타나며, 역방향 흐름이 큰 경우에는 재순환 영역의 흐름은 보 상류의 흐름과 분리되는 닫힌 박리흐름이 발생하였다. 역방향 흐름이 가장 큰 경우, 보 전방의 박리흐름은 보의 상단을 넘는 것으로 관찰되었다. 이러한 결과를 통해 보 마루에서 발생하는 박리흐름이 보 전방에 박리흐름에 영향을 미치는 것으로 파악되었다. 조건부 평균된 역방향 흐름의 면적과 박리 지점(separation point)의 관계를 분석한 결과, 역방향 흐름의 오른쪽으로 기울어진 분포와 대규모 흐름 방출 현상이 관측되었다. 박리 지점의 위치와 수리 매개변수의 관계를 분석한 결과, 상류의 수심 증가에 따라 증가하는 경향이 나타났다.

• Tunnel and Underground Space
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• v.34 no.1
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• pp.71-87
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• 2024

In deep geological disposal of high-level radioactive waste, the surrounding rock at the immediate vicinity of the deposition hole may experience localized changes in permeability due to in-situ stress at depth, swelling pressure from resaturated bentonite buffer, and the heat generated from the decay of radioactive isotopes. In this study, experimental data on changes in permeability of granite, a promising candidate rock type in South Korea, were obtained by applying various confining pressures and temperature conditions expected in the actual disposal environment. By conducting the permeability test on KURT granite specimens under three or more hydrostatic pressure conditions, the relation in which the permeability decreases exponentially as the confining pressure increases was derived. The temperature-induced changes in permeability were found to be negligible at temperatures below the expected maximum of 90℃. In addition, by establishing a relation in which the initial permeability is proportional to the power of the initial porosity, it was possible to estimate permeability value for granite with a specific porosity under a certain confining pressure.

• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.411-424
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• 2011

The studies of congruence in organizational research have explored the concepts such as person-job fit person-organization fit, or person-environment fit. The relevant studies dealt with the fit level as an important influencing factor on the performance. In particular, researchers have agreed that employees can be motivated by the high level fit of person-organization. However, few research developing an alternative methodological approach has been done. For the purpose mentioned above the statistics like D, |D| or $D^2$ and the Q values such as Q(the correlation between two sets of interval measures) or $Q_r$(the correlation between two rankings) have been conventionally adopted in spite of numerous methodological problems. In general, these traditional indices such as difference scores, or Q values, are nondirectional and add an extra weight to differences of lager magnitude. Therefore, Edwards (1993) introduced the polynomial regression and the response surface analysis to overcome flaws with conventional approaches. However, the method-ological approaches did not reflect the profile characteristics of person-organizational value fit and wouldn't be a proper solution for the fit level of person-organization value maximizing performance. Hence, this paper investigates alternative methodological approaches, the multivariate polynomial regression and the multiple response surface analysis, to avoid the problems issued from conventional ways.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.751-754
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• 2010

본 연구는 초등학교 5, 6학년 학생들을 대상으로 인터넷 게임중독과 자아통제, 충동성과의 관계를 파악하여 올바른 인터넷 사용 문화를 장려하고, 과도한 인터넷 사용 방지교육을 위한 기초자료를 제공하고자 시도되었다. 자료는 2009년 11월 9일에서 11월 30일까지 익산시내 3개 초등학교를 임의로 선정하여 5, 6학년 학생 927명을 대상으로 조사하였다. 자료 분석은 SPSS WIN(12.0 한글판) 프로그램을 이용하여 카이제곱검정, t-검정, 일원배치 분산분석, 다중회귀분석의 통계적 방법을 이용하였다. 본 연구의 결과로는 대상자의 인터넷 게임중독 정도는 '정상' 483명(54.3%), '중독초기' 363명(40.8%), '중독중증' 43명(4.8%)으로 나타났다. 일반적 특성에 따른 인터넷 게임중독 정도를 분석한 결과 성별(p<0.01)이 유의한 차이가 있었으며 컴퓨터 사용 특성에 따른 인터넷 게임중독 정도는 이용장소(p<0.05), 주요활동(p<0.01), 평일 이용시간(p<0.01), 주말 이용시간(p<0.01)이 유의한 차이가 있었다. 또한, 인터넷 게임중독과 자아통제와의 관계를 분석한 결과 인터넷 게임중독 경향이 높을수록 자아통제 점수가 낮으며, 자아통제 점수가 높을수록 인터넷 게임중독 경향이 낮은 것으로 조사되었으며(p<0.01) 인터넷 게임중독과 충동성과의 관계를 분석한 결과 인터넷 게임중독 경향이 높을수록 충동성 점수가 높은 것으로 조사 되었는데, 이는 충동성 점수가 낮을수록 인터넷 게임중독 경향이 낮음을 의미한다(p<0.01). 자아통제와 충동성과의 관계를 분석한 결과 자아통제가 낮을수록 충동성이 높으며, 자아통제가 높을수록 충동성이 낮은 것으로 나타나서 자아통제와 충동성은 서로 반대 개념인 것을 알 수 있었으며(p<0.01) 인터넷 게임중독과 자아통제, 충동성과의 다중회귀분석 결과 유의한 영향을 주는 변수는 성별(p<0.01), 학교성적(p<0.01), 주요활동(p<0.01), 평일 이용시간(p<0.01), 주말 이용시간(p<0.01), 자아통제(p<0.01), 충동성(p<0.01)이었다. 여학생보다 남학생이, 학교성적이 높을수록, 주요활동이 비학습관련인 경우, 평일 이용시간이 1시간이상 이용할수록, 주말 이용시간이 2시간이상 많이 이용할수록, 자아통제가 낮을수록, 충동성이 높을수록, 인터넷 게임중독 경향이 높은 것으로 나타났다. 이상의 결과를 종합해 보면, 인터넷 게임중독 경향이 높을수록 자아통제 정도가 낮게, 충동성 정도는 높게 나타나고, 인터넷 게임중독 경향이 낮을수록 자아통제 정도가 높게, 충동성 정도는 낮게 나타나는 것을 알 수 있다. 또한 자아통제와 충동성은 상반된 개념으로 자아통제 정도가 높을수록 충동성은 낮아지고 자아통제 정도가 낮을수록 충동성이 높아짐을 알 수 있다.