• Korean Journal of Environment and Ecology
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• v.22 no.6
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• pp.632-639
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• 2008

This paper deals with feeding site distribution aspect and seasonal distribution change of the wintering geese in Cheonsu bay and reclaimed area from October 2006 to March 2007. Geese were distributed mostly in agricultural land(rice field) during day time. According to the distribution map by maximum counts, observed geese of agricultural land were frequently distributed in large agricultural land. Especially, Geese were more used agricultural land near the reservoir where used as roosting site than the other sites. Diurnal feeding site of the geese were agricultural land near the reservoir with huge flock during early wintering season(October), but geese were used the agricultural land far from reservoir after mid wintering season(after January). The feeding flock size of Geese were decreased and feeding site was more far from the reservoir than in mid wintering season during late wintering season(March). Habitat use rate of the quadrat area where below 1km from the reservoir was most high in early wintering season. Contrary, habitat use rate where 2km far from the reservoir was shown lowest habitat use rate in early wintering season, but it was increased during mid wintering season(January) and decreased after mid wintering season. Habitat use rate of the agricultural land where 2km below and 1 km far from reservoir was shown middle rate, but it was increased until November and decreased after November. This result shown that feeding site preference of the wintering geese was affected by distance from roosting site(reservoir), and feeding site was changed as a food sources decreasing by stay time of geese flock.

• Journal of Korean Society of Transportation
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• v.36 no.3
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• pp.169-183
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• 2018

Aggressive driving leads to a greater crash potential because it threatens surrounding vehicles. This study conducted traffic simulation experiments using driving behavior data obtained from multi-agent driving simulations. VISSIM traffic simulator and surrogate safety assessment model (SSAM) were used to identify the impacts of aggressive driving on traffic stream in terms of safety and operational efficiency. Market penetration rates (MPR) of aggressive driving vehicle, coupled with various traffic conditions, were taken into consideration in analyzing the impacts. As expected, it was identified that aggressive driving vehicles tended to deteriorate the traffic safety performance. From the perspective of operational efficiency, interesting results were observable. Under level of service (LOS) A, B, and C, it was observed that the average travel speed increased with greater MPRs. Conversely, the average travel speed decreased with under LOS D and E conditions. The outcome of this study would be effectively used for developing safety-related policies for reducing aggressive driving behavior.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.12
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• pp.1979-1990
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• 2009

This study suggests apparel sizing systems for obese women in their twenties to fifties. Size Korea body measurement data were used for sampling the obese subjects by obesity judgment indices. A total of 7 obesity judgment indices frequently used in the clothing field were inspected and the measurement data of 499 females defined as "obese" by over 5 obesity judgment indices were analyzed. The results of the study were as follows: A total of 2,212 female body measurement data for the Size Korea Project were collected. These were compared with the 499 data of the obese women in the study. Except for all heights and some lengths correlating with heights, the measurements of obese women were larger than the entire group of females. Bust girth, hip girth, and height were selected as control dimensions of the outerwear covering the upper body; waist girth and hip girth were selected as control dimensions of the outerwear covering the lower body. In each crosstabulation table, 3cm pitches and 5cm pitches by bust girth, waist girth, and hip girth were compared in the aspects of coverage and coverage efficiency. Finally, sizing charts for outerwear covering the upper body and the lower body of obese women were established in the study through the comparison of the coverage and the coverage efficiency. These Size charts were given by 5cm pitches as final sizing systems. Size number of outerwear covering the upper body was 10 and size number of outerwear covering the lower body was 9. In addition, the body measurements of control dimensions and referable dimensions for making garments are given.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.297-309
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• 2016

This study was carried out to investigate the differences in sedimentary environments and benthic polychaete communities between farming grounds and natural habitats (non-farming ground) in Gamak Bay. Sampling stations of natural habitats were evenly distributed in the entire bay. And mussel farm, oyster farm and ark-shell farm were selected as farming grounds. Dominant sedimentary facies was mud in most sampling stations of farming grounds and natural habitats. However organic contents were higher in the farming grounds than natural habitats of the bay. The species number and mean density of polychaetous community in the natural habitats were greater than those from the farming grounds. Lumbrineris longifolia, known as potential organic enrichment indicator species, was first dominant species both in farming grounds and natural habitats of the bay. However, the next dominant species consisted of different species between two benthic habitats. As a result of community analysis using cluster analysis and nMDS, the natural habitats were divided into several station groups, but most of stations in farming grounds were clustered into one group. Pearson' correlation analysis and PCA showed high relationships between sedimentary environmental factors and benthic polychaetous community in natural habitats, but low or no relationships in farming grounds. That means benthic polychaetous community established in farming ground was under unusual condition such as high input of organic matter. Thus it is necessary to improve the benthic environmental quality of the farming grounds as well as the north-western inner part in Gamak Bay through long-term monitoring efforts.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.589-599
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• 2021

Purpose To analyze the success and complication rates and factors associated with technical failure of the ultrasound (US)-guided percutaneous thrombin injection of femoral artery pseudoaneurysms caused by vascular access. Materials and Methods Records of 30 patients with post-catheterization femoral artery pseudoaneurysms who had been treated with US-guided percutaneous thrombin injections in the department of radiology between March 2009 and June 2019 were retrospectively analyzed. The lesion was diagnosed based on US or contrast-enhanced CT. The characteristics of the patients and their lesions were analyzed. Results The mean patient age was 67.8 years. The mean diameter of the pseudoaneurysmal sac was 20.88 mm (5-40 mm). Twenty patients (66.6%) obtained complete thrombosis after the primary injection, while 10 patients (33.3%) obtained partial thrombosis. The number of patients with a low platelet count (< 130 k/µL) was significantly higher in the partial thrombosis group than in the complete thrombosis group (p = 0.02). No substantial procedure-related complications were found in any patient. Conclusion The US-guided percutaneous thrombin injection is considered an initial treatment option for pseudoaneurysms caused by vascular access because of its safety and efficacy.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1284-1288
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• 2010

부자의 보정계수를 결정하는 방법은 크게 다음과 같이 현행 방법과 WMO 제안 방법으로 구분할 수 있다. 현재 국내에서 적용하고 있는 방법으로 표면부자부터 4.0m부자까지 사용된 부자의 종류에 따라 사전에 정해진 보정계수를 적용한다. WMO에서 제안하고 있는 방법은 해당 하천의 수심과 사용된 부자 흘수(吃水)의 상대적 비로부터 산정되는 보정계수를 적용하는 방법이다. 본 연구는 국내 유량측정기술의 개선을 위한 선행연구로, '07~'08년의 국토해양부 부자 측정성과(86개 지점 788개 유량측정성과)를 현행 방법 및 WMO 제안 방법을 적용하여 산정된 유량을 비교 분석하였다. 분석 결과, WMO 방법을 이용하여 산정된 유량은 각 측정성과별로 현행 방법을 적용하여 산정한 유량 대비 -7.69~+7.20%의 차이를 보였으며, 평균 1.57% 작게 산정되었다. 각 수계별로 한강은 -5.90~+2.55% 범위에서 평균 -2.11%, 낙동강은 -7.69~+7.20% 범위에서 평균 -2.45%, 금강은 -7.39~+7.03% 범위에서 평균 -0.52%, 영산강은 -6.50~+2.58% 범위에서 평균 -1.59% 로 산정되었다. 또한 각 성과에 대해 각 지점의 주요 인자들과의 상관성을 검토한 결과, 산정된 유량의 차이는 지점의 수심에 매우 큰 상관성을 가지는 것으로 나타났다. 저수심에서는 WMO 방법이 상대적으로 크게 산정되었으며, 고수심에서는 현행 방법을 적용하여 산정한 유량이 상대적으로 크게 나타났다. 특히 약 8m 이상의 수심에서는 보다 큰 차이가 나타나는 것을 확인할 수 있었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.819-829
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• 2018

The bed change survey was carried out and its tendency was analyzed at the downstream of the Singok Submerged Weir in the Han River Estuary (HRE). In order to focus on the bed change in the low flow channel, we calculated the mean bed elevation based on the bankfull discharge. Thanks to the amount of bed changes calculated by using the 'averaged bed', we could compare the riverbeds of various periods with consistent criteria. In the HRE, revealed was the bed change cycle between degradation by flood and aggradation by tide at the non-flood season.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.703-708
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• 2022

K-means clustering is a representative clustering technique. However, there is a limitation in not being able to integrate the performance evaluation scale and the method of determining the minimum number of clusters. In this paper, a method for numerically determining the minimum number of clusters is introduced. The explained variance is presented as an integrated measure. We propose that the k-means clustering method should be performed in the subspace of the PCA in order to simultaneously satisfy the minimum number of clusters and the threshold of the explained variance. It aims to present an explanation in principle why principal component analysis and k-means clustering are sequentially performed in pattern recognition and machine learning.

• Korean journal of applied entomology
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• v.42 no.1
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• pp.57-63
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• 2003

Accurate forecasting of occurrence time and abundance of insect pests is essential for developing technology of integrated pest management system. Digital image processing algorithms were utilized to automatically recognize rice planthoppers which are major insect pests in the rice cultivation field and were subsequently used to estimate densities in the field for efficient forecasting of insect pests. To the images taken in the rice field, image decomposition, top-hat transformation, threshold, and minimum and maximum filter were implemented for patterning individually the brown planthopper specimens attached at the bottom area of rice stems. In average 95.8cio of images were correctly recognized for estimating densities by the developed system, and the recognition rate was higher than that obtained from direct observations by experienced observers. Furthermore, the size of the recognized specimens was measured and was used for estimating the age structure in the observed brown planthopper populations.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.99-111
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• 2002

전산기술의 발달에 힘입어 근래에 모의실험을 이용한 연속교통류의 미시적 분석이 활발히 수행되고 있고 다양한 모의실험 전산모형이 소개되고 있다. 미시적 연속교통류 전산모의실험은 차량추종모형과 차로변경모형을 적용하여 다양한 운전자들의 차량운행행태를 모사하여 분석하는 실험이다. 전산모형은 난수를 토대로 차량의 자유속도와 초기 발생 차로를 배정하기 때문에 낮은 자유속도를 할당받은 차량이 높은 속도의 차로(예:1차로)로 발생되는 경우가 발생한다. 많은 모의실험모형이 사용하고 있는 차로변경의 가정이 "운전자는 자신이 원하는 속도(자유속도)를 유지한다"는 것이며 그러한 가정만의 적용으로 인해 현실적이지 않은 차로 이용률이 결과되고, 따라서 전산모형을 통한 교통류 흐름분석에 문제를 제공하고 있다. 본 논문에서는 미국 도로국에서 20여년 동안 개발되고 수정되어왔으며 현재 실용적으로 가장 많이 사용되고 있는 Freeway Simulation(FRESIM) 전산모형이 내재한 차로변경모형을 토대로 고속도로 기본구간에서의 선택적 차로변경모형을 제시한다. 제시된 모형에서는 (1)저속의 선행차량이 고속의 후행차량에게 차로를 양보하는 가정이 새롭게 추가되고 (2)FRESIM모형에서 사용하는 상수값을 국내 현장조사를 통하여 도출된 분포식을 통한 값으로 대체하였다. 수집된 자료분석결과 연속 교통류에서의 15% 차두시간은 1.34초이며 차로변경시간은 평균 2.22초인 F분포를 따르고, 자유속도는 정규분포를 따르는 것으로 결과되었다. 모의실험결과 무작위난수를 토대로 배정된 차로로 생성된 차량들이 새롭게 제시된 차로변경모형의 적용으로 현장 차로이용률을 95% 신뢰수준에서 모사하는 것으로 분석되었다.