• 대한교통학회지
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• 제24권2호
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• pp.113-124
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• 2006

교통안전시설 중 중앙분리대는 정면충돌 사고 예방에 효과가 있다고 인식되어 4차로 이상 국도를 대상으로 설치가 이루어지고 있다. 중앙분리대 설치효과분석에 관한 연구는 국내 외에서 지속적으로 이루어지고 있는데. 주로 해당구간의 전체적인 사고감소효과를 제시하고 있다. 즉, 지점에서 사고유형별 또는 심각도별로 사고발생형태가 어떻게 변화되는지에 대한 연구가 미미한 실정이다. 국외에서는 주로 중앙분리대 설치유형에 따른 사고감소효과를 산정하고 있으며, 국내에서는 일부 사고유형별 감소효과를 산정한 사례가 있기는 하나 시설물 설치전 후 각 1년만의 사고자료만을 이용함으로써 도출된 값의 통계적 신뢰성을 확보하지 못하고 있다. 이에 본 연구에서는 중앙분리대 설치에 따른 사고유형별 사고심각도별 사고전환효과를 추정하고자 한다 이를 위하여 중앙분리대가 설치된 국토 깊차로 108.6km에 대하여 사업전 후 총 7년간의 교통사고자료, 안전시설물 설치이력과 도로선형요소에 대한 조사와 자료수집이 이루어졌다 다음으로 경험적베이즈(Empirical Bayes)기법을 이용한 모형구축과 사고유형 심각도의 사고전환효과를 추정하였다. 연구결과는 향후 중앙분리대 관련 정책집행과 시설기준제시에 활용될 수 있을 것으로 기대된다.

• 대한소아치과학회지
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• 제32권3호
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• pp.525-530
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• 2005

정중이개란 상악 중절치 사이의 치간이개를 말한다. 이는 혼합 치열기에서 ugly ducking stage에 흔히 관찰할 수 있으며 일반적으로 견치가 맹출하면서 자연적으로 소실되므로 꼭 치료가 필요한 것은 아니다. 그러나 견치 맹출 후에도 정중이개가 2mm이하로 계속 존재하거나 견치 맹출 전이라도 3mm이상의 정중이개가 존재하는 경우에서는 치료의 적응증이 될 수 있다. 특히 후자의 경우 심미적인 면에서 뿐만 아니라, 이로 인해 측절치와 견치의 맹출공간이 부족해지는 문제가 발생하므로 교정치료가 권장된다. 정중이개 치료시 사용되는 장치물은 finger spring 등을 이용한 가철성 장치물과, 교정용 band, tube, bracket 등을 부착시켜 rubber elastics이나 coil spring 등을 사용하는 고정성 장치물로 나뉘어진다. 그러나 정중이개의 치료를 위해 rubber band를 band, tube, bracket 등과 같은 적절한 부가장치 없이 사용하면 rubber band가 치근은 따라 치은 하방으로 이동하게 되고 치주 인대를 파괴하며 치근단 부위에 이르러 치아동요, 치아정출 및 탈락 등 치아에 치명적인 손상을 입힐 수 있다. 본 증례는 정중이개의 치료를 위해 부적절하게 rubber band를 사용하여 외상을 받은 치아를 관찰하여 다소의 지견을 얻었기에 이를 보고하는 바이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(4)
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• pp.81-84
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• 2000

Cellular automata are discrete dynamical systems whose behaviour is completely specified in terms of a local relation. If cellular automata convergence to fixed points, then it can be used to image processing. From the generalized Potts automata point of view, we propose in this paper a cellular automata technique for reducing image noise. To minimize blurring effect, an algorithm based on neighborhood median computation is Preferred. Experimental results are reported.

• 가정과삶의질연구
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• 제17권4호
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• pp.133-148
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• 1999

This study is conducted a survey of consumer problems and dissatisfactionand their complaining behavior with door to door and mail order sellings. Results of the study show that both door to door selling and mail order selling the level of consumer complaining behavior was below median point. Path analysis of the variables affected complaining behavior showed that total causal effect to the biggest consumer dissatisfaction.

• 한국컴퓨터정보학회논문지
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• 제20권7호
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• pp.41-47
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• 2015

The bandwidth minimization problem (BMP) has been classified as NP-complete because the polynomial time algorithm to find the optimal solution has been unknown yet. This paper suggests polynomial time heuristic algorithm is to find the solution of bandwidth minimization problem. To find the minimum bandwidth ${\phi}^*=_{min}{\phi}(G)$, ${\phi}(G)=_{max}\{{\mid}f(v_i)-f(v_j):v_i,v_j{\in}E\}$ for given graph G=(V,E), m=|V|,n=|E|, the proposed algorithm sets the maximum degree vertex $v_i$ in graph G into global central point (GCP), and labels the median value ${\lceil}m+1/2{\rceil}$ between [1,m] range. The graph G is partitioned into subgroup, the maximum degree vertex in each subgroup is set to local central point (LCP), and we adjust the label of LCP per each subgroup as possible as minimum distance from GCP. The proposed algorithm requires O(mn) time complexity for label to all of vertices. For various twelve graph, the proposed algorithm can be obtains the same result as known optimal solution. For one graph, the proposed algorithm can be improve on known solution.

• Journal of Ecology and Environment
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• 제40권1호
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• pp.66-74
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• 2016

Background: When developing water quality improvement strategies for eutrophic lakes, questions may arise about the relative importance of point sources and nonpoint sources of phosphorus. For example, there is some skepticism regarding the effectiveness of partial reductions in phosphorus loading; because phosphorus concentrations are too high in hypertrophic lakes, in-lake phosphorus concentrations might still remain within typical range for eutrophic lakes even after the reduction of phosphorus loading. For this study, water quality and the phytoplankton and zooplankton communities were monitored in a hypertrophic reservoir (Lake Wangsong) before and after the reduction of phosphorus loading from a point source (a sewage treatment plant) by the installation of a chemical phosphorus-removal process. Results: Before phosphorus removal, Lake Wangsong was classified as hypertrophic with a median phosphorus concentration of $0.232mg\;L^{-1}$ and a median chlorophyll-a concentration of $112mg\;L^{-1}$. The dominant phytoplankton were filamentous cyanobacteria for the most of the ice-free season. Following the installation of the advanced treatment process, phosphorus concentrations were reduced to $81mg\;L^{-1}$, and the N/P atomic ratio increased from 42 to 102. Chlorophyll-a concentrations decreased to $42{\mu}g\;L^{-1}$, and the duration of cyanobacterial dominance was confined to the summer season. Cyanobacteria in spring and autumn were replaced by diatoms and cryptomonads. Filamentous cyanobacteria in summer were replaced by colony-forming unicellular Microcystis spp. It was remarkable that zooplankton biomass increased despite the decrease in phytoplankton biomass, and especially cladoceran zooplankton which increased drastically. These responses to the reduction of point source P loading to Lake Wangsong imply that reducing the point source P loading can have a big impact even when nonpoint sources account for a large fraction of the total annual phosphorus loading. Conclusions: Our results also show that the phytoplankton community can shift to decreased cyanobacterial dominance and the zooplankton community can shift to higher cladoceran dominance, even when phosphorus concentrations remain within the typical range for eutrophic lakes following the reduction of phosphorus loading.

• 한국환경보건학회지
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• 제47권4호
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• pp.320-329
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• 2021

Background: Smoking exposure may be objectively assessed through specific biomarkers. The most common biomarker for smoking is cotinine concentration in urine, and setting an optimal cut-off point can accurately classify smoking status. Such a cut-off point for Korean adolescents has never been studied. Objectives: The aim of this study was to determine a cut-off point for urinary cotinine concentration for the discrimination of smoking in adolescents. Methods: Participants were adolescents aged 13~18 years who participated in the third cycle of the Korean National Environmental Health Survey. We used urine samples to confirm the level of cotinine concentrations. Smoking status was determined by self-reported questionnaire. We identified the optimal cotinine cut-off point for discriminating smoking status using receiver operating characteristic curve analysis. Results: Of the 904 participants, 28 (3.1%) were smokers, among whom 20 (71.4%) were male. The median urinary cotinine concentrations in smokers was 218 ㎍/L (male: 215 ㎍/L, female: 303 ㎍/L), and that in non-smokers was 1.31 ㎍/L (male: 1.46 ㎍/L, female: 1.18 ㎍/L). We found significant differences in urinary cotinine concentration according to smoking status and sex (p<0.001). Urinary cotinine concentrations performed well for identifying smoking adolescents [area under the curve: 0.954 (male: 0.963, female: 0.908)]. The cut-off that optimally distinguished smokers from non-smokers was 39.85 ㎍/L (sensitivity: 89.3%, specificity: 97.4%). Male [39.85 ㎍/L (sensitivity: 90.0%, specificity: 94.9%)] had a different optimal cut-off point than female [26.26 ㎍/L (sensitivity: 87.5%, specificity: 99.6%)]. Conclusions: This study determined a cut-off point for urinary cotinine of 39.85 ㎍/L (male: 39.85 ㎍/L, female: 26.26 ㎍/L) to distinguish smokers from non-smokers in adolescents.

• 대한한의학회지
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• 제20권2호
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• pp.157-164
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• 1999

This study focused on the method of interpreting Moire's topography. There has been no standard of interpretation which informed, this study, The conclusions arc as follows: Miore's image closed contour lines which is consisted of points. These points in one contour have the same distances from the screen to the patient's back. Moire's index means the number of contour gaps from symmetrical point of a specific point with the axis of central line. The number of contours which pass the median line means the degree of antero-posterior curvature.

• Communications for Statistical Applications and Methods
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• 제22권3호
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• pp.241-253
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• 2015

In this paper we predict the track of typhoons using a Bayesian principal component regression model based on wind field data. Data is obtained at each time point and we applied the Bayesian principal component regression model to conduct the track prediction based on the time point. Based on regression model, we applied to variable selection prior and two kinds of prior distribution; normal and Laplace distribution. We show prediction results based on Bayesian Model Averaging (BMA) estimator and Median Probability Model (MPM) estimator. We analysis 8 typhoons in 2006 using data obtained from previous 6 years (2000-2005). We compare our prediction results with a moving-nest typhoon model (MTM) proposed by the Korea Meteorological Administration. We posit that is possible to predict the track of a typhoon accurately using only a statistical model and without a dynamical model.

• Journal of the Korean Statistical Society
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• 제30권4호
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• pp.679-691
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• 2001

Two truncated sequential tests are developed for the two-sample scale problem based on the usual Wilcoxon rank-sum statistic for two different dispersion indices - absolute median deviations, when the medians of the two populations X and Y are equal or known and sums of squared mean deviations, when the medians are either unknown or unequal. The first test is briefly called SWAMD test and the second SWSMD test. For the SWAMD test, the percentile points for both the one-sided and two-sided alternatives, (equation omitted) have been found by Wiener approximation and their values computed for a range of values of a and N; analytical expression for the power function has been derived through Wiener process and its performance studied for various sequential designs for exponential distribution. This test has been illustrated by a numerical example. All the results of the SWAMD test, being directly applicable to the SWSMD test, are not dealt with separately Both the tests are compared and their suitable applications indicated.