• 대한원격탐사학회지
• /
• 제31권4호
• /
• pp.293-302
• /
• 2015

Water body extraction is significant for flood disaster monitoring using satellite imagery. Conventional methods have focused on finding an index, which highlights water body and suppresses non-water body such as vegetation or soil area. The Normalized Difference Water Index (NDWI) is typically used to extract water body from satellite images. The drawback of NDWI, however, is that some man-made objects in built-up areas have NDWI values similar to water body. The objective of this paper is to propose a new method that could extract correctly water body with built-up areas in before and after images of flood. We first create a two-element feature vector consisting of NDWI and a Near InfRared band (NIR) and then select a training site on water body area. After computing the mean vector and the covariance matrix of the training site, we classify each pixel into water body based on Mahalanobis distance. We also register before and after images of flood using outlier removal and triangulation-based local transformation. We finally create a change map by combining the before-flooding water body and after-flooding water body. The experimental results show that the overall accuracy and Kappa coefficient of the proposed method were 97.25% and 94.14%, respectively, while those of the NDWI method were 89.5% and 69.6%, respectively.

• 한국멀티미디어학회논문지
• /
• 제21권12호
• /
• pp.1431-1438
• /
• 2018

In this paper, we proposed a river water level detection and tracking of the river or dams based on image processing system. In past, most of the water level detection system used various water sensors. Those water sensors works perfectly but have many drawbacks such as high cost and harsh weather. Water level monitoring system helps in forecasting early river disasters and maintenance of the water body area. However, the early river disaster warning system introduces many conflicting requirements. Surveillance camera based water level detection system depends on either the area of interest from the water body or on optical flow algorithm. This proposed system is focused on water scaling area of a river or dam to detect water level. After the detection of scale area from water body, the proposed algorithm will immediately focus on the digits available on that area. Using the numbers on the scale, water level of the river is predicted. This proposed system is successfully tested on different water bodies to detect the water level area and predicted the water level.

• 대한원격탐사학회지
• /
• 제32권5호
• /
• pp.471-482
• /
• 2016

본 논문에서는 수계 영역의 감독 분류 성능을 향상시키기 위하여 블록 기반의 영상 분할과 수계 경계의 확장을 이용하는 수계 검출 방법을 제안한다. 초기 수계 영역을 추출하기 위하여 수계 훈련 지역의 Normalized Difference Water Index (NDWI) 및 Near Infrared (NIR) 밴드 영상의 분광 정보를 이용하여 Mahalanobis 거리 영상을 생성한다. Mahalanobis 거리 영상에 포함된 잡음 성분의 영향을 감소시키기 위해서 인접한 화소의 연결 강도에 의해 확산 계수가 제어되는 평균 곡률 확산을 적용한 후에 초기 수계 영역을 추출한다. 추출된 수계 영상을 같은 크기의 블록으로 분할한 후에 수계 경계에 속하는 수계 영역의 정보를 이용하여 수계 영역을 갱신한다. 수계 경계에 속하는 수계 영역과 수계 훈련 지역 사이의 통계적인 거리가 임계값 이하이면, 수계 영역 갱신을 반복적으로 수행한다. 제안한 알고리즘을 KOMPSAT-2 영상에 적용한 결과 블록 크기가 $11{\times}11$에서 $19{\times}19$사이인 경우에 overall accuracy는 99.47%에서 99.53%, Kappa coefficient는 95.07%에서 95.80%의 분류 정확도를 보였다.

• 환경영향평가
• /
• 제15권6호
• /
• pp.407-415
• /
• 2006

This study carried out submerged area due to Dam construction in the near future. It includes species classification of plant, survey of community structure, examination of pollutant load and assessment of water quality impact. The vascular plants of this area are listed 224 taxa; 64 families, 168 genera, 193 species, 30 varieties and 1 form. This study area is classified into total 21 communities, most community was consist of grass vegetation. Among the communities, Erigeron annuus ($869,286m^2$, 22%) community was dominant and Erigeron annuus-Avena fatua comminity (16%) was subdominant until May, and then Erigeron canadensis community occupied most area to $1,774,985m^2$ (32%) from May to July. For the evaluation of water quality impact due to submerged macrophyte, nutrient release test was conducted both dead body macrophyte and living body macrophyte. The results of release test show that T-N is not released at dead body macrophyte, but it is released at living body macrophyte, especially living body Artemisia priceps var. orientalis shows 1.436mgN/g. At release test of dead body macrophyte, T-P release rate of Erigeron annuus shows 0.500mgP/g at the top of them and it also shows 0.436mgP/g at Erigeron annuus of living body macrophyte. T-N load of submerged macrophyte shows 0.76% by comparison of total load on watershed and T-P load of that shows 3.61%. In case of removal macrophyte for reduction of pollutant load in submerged area, T-N load of submerged macrophyte changes from 0.76% to 0.15% by comparison of total load on watershed and T-P load of that changes from 3.61% to 0.72%.

• 대한원격탐사학회지
• /
• 제31권4호
• /
• pp.337-346
• /
• 2015

Water body extraction based on backscatter information is an essential process to analyze floodaffected areas from Synthetic Aperture Radar (SAR) image. Water body in SAR image tends to have low backscatter values due to homogeneous surface of water, while non-water body has higher backscatter values than water body. Non-water body, however, may also have low backscatter values in high resolution SAR image such as Kompsat-5 image, depending on surface characteristic of the ground. The objective of this paper is to present a method to increase backscatter contrast between water body and non-water body and also to remove efficiently misclassified pixels beyond true water body area. We create an entropy image using a Gray Level Co-occurrence Matrix (GLCM) and classify the entropy image into water body and non-water body pixels by thresholding of the entropy image. In order to reduce the effect of threshold value, we also propose Water Body Texture Index (WBTI), which measures simultaneously the occurrence of repeated water body pixel pair and the uniformity of water body in the binary entropy image. The proposed method produced high overall accuracy of 99.00% and Kappa coefficient of 90.38% in water body extraction using Kompsat-5 image. The accuracy analysis indicates that the proposed WBTI method is less affected by the choice of threshold value and successfully maintains high overall accuracy and Kappa coefficient in wide threshold range.

• 대한한의학회지
• /
• 제22권4호
• /
• pp.114-120
• /
• 2001

Objectives : Man adapts himself to nature, so accordingly as he grows up, changes of body composition appear. This study measured the changes of body compositions on the ground of Sasang constitution and seasons Methods : 253 middle school students who live in Busan were studied from the 20th of March, 1999 to the 20th of March, 2001. We measured height and body compositions with Inbody 3.0, six times during that period. Results : According as they grew up, total body water, muscle area, body weight, BMI (Body Mass Index), BMR (Basal Metabolic Rate), ACM (Arm Muscle Circumference), and BCM (Body Cell Mass) increased, but fat body weight ratio decreased. From March to June, total body water, muscle area, height, ACM, and BCM increased. From September to December fat body weight, fat body weight ratio, waist hip ratio increased as compared with other seasons. Height of Soyangin and BMI of both Soyangin and Taeumin increased more than those of other groups, with statistical significance Conclusions : The growth of man is adapting oneself to changes of nature, and it corresponds to the theory of (correspondence between man and universe).

• 대한지역사회영양학회지
• /
• 제4권3호
• /
• pp.403-411
• /
• 1999

The purpose of this study was to investigate the physical characteristics and instrumental activities of daily living(IADL) of the elderly (85+). The subjects were three-hundred elderly people over the age of 85, living in Kyungpook Sung-Ju area who have no problems in daily living. The survey on anthropometric measures and IADL were carried out by individual measurement and interviews using measuring devices and questionnaires. The subject group of the study was composed of 27% males and 73% females, the average age being 87 years old. Notable physical features of the subjects include considerably short statues and small physiques compared to the average Korean elder. The mean Body Mass Index(BMI) was 20.9. The average percentage of body fat in male and female was 21.7% and 29.5% respectively, and the average waist/hip ratio(WHR) was 0.9 and 0.85 respectively. The percentage of the subjects who were able to perform all the IADL was 51% in males and 25% in females. The male subjects were more capable than the females in all the IADL except for preparing meals. BMI showed positive correlations withy weight(r=699), WHR(r=0.157), body fat percentage(r=0.57), lean body mass(r=0368) and total body water(r=0.368). WHR also had positive correlation with weight(r=0.184), BMI(r=0.157), lean body mass(r=0.149) and total body water (r=0.148). Body fat percentage had a positive correlation with weight(r=0.147) and BMI(r=0.265) and total body water(r=0.265). In summary, the elderly(85+) in the Sung-Ju area had considerably smaller physiques than the average Korean elderly and showed a normal range of BMI in average. The IADL of the elderly(85+) appeared to have a positive correlation with lean body mass and total body water and a negative correlation with body fat percentage.

• Nuclear Engineering and Technology
• /
• 제54권3호
• /
• pp.849-859
• /
• 2022

Feed-water valves (FWVs) are used to regulate the flow rate of water entering steam generators, which are very important devices in nuclear power plants. Due to the working environment of relatively high pressure and temperature, there is strength failure problem of valve body in some cases. Based on the thermo-fluid-solid coupling model, the valve body stress of the feed-water valve in the opening process is investigated. The flow field characteristics inside the valve and temperature change of the valve body with time are studied. The stress analysis of the valve body is carried out considering mechanical stress and thermal stress comprehensively. The results show that the area with relatively high-velocity area moves gradually from the bottom of the cross section to the top of the cross section with the increase of the opening degree. The whole valve body reaches the same temperature of 250 ℃ at the time of 1894 s. The maximum stress of the valve body meets the design requirements by stress assessment. This work can be referred for the design of FWVs and other similar valves.

• KSTLE International Journal
• /
• 제4권1호
• /
• pp.8-13
• /
• 2003

Abrasion in fretting wear mechanism is studied experimentally with the specimens of two different shapes of spacer grid spring and fuel tubes of a nuclear fuel. Reciprocating sliding wear test has been carried out in the environment of air and water at room temperature. Especially, third body abrasion is referred to for explaining the wear region expansion found during the slip displacement increase with constant normal contact farce. It is found that the expansion behaviour depends on the contact shape. The small clearance between the tube and spring seems to be the preferable region of the wear particle accumulation, which causes third body abrasion of the non-contact area. Even in water environment the third body abrasion occurs apparently. Since the abrasion on the clearance contributes wear volume, the influence of the contact shape on the severity of third body abrasion should be considered to improve the grid spring design in the point of restraining wear damage of a nuclear fuel.

• 사상체질의학회지
• /
• 제12권2호
• /
• pp.132-142
• /
• 2000

Purpose In Sasang Constitution Medicine, persons are divided into four types such as Taeyangin, Taeumin, Soyangin and Soeumin according to their appearance, moral nature and characteristic of constitutional symptoms. In teenager group, diagnosis of constitution based on their appearance was so difficult that we adopted new diagnostic method which measures and compares body compositions. Methods 180 middle school students who live in Pusan were studied from 20th of March, 1999 to 20th of March, 2000. After practicing Questionnaire(I), QSCC(Questionnaire of Sasang Constitution) I , QSCCII, we have measured the height and body compositions with Inbody 3.0, five times. Results 1. The results of Sasang Constitution analysis showed 91 students were classified as Taeumin(50.3%), 75 as Soyangin(41.4%), 14 as Soeumin(7.7%), and 1 as Taeyangin(0.6%). 2. The level of total body water, muscle area, BMR(Basal Metabolic Rate), BCM(Body Cell Mass), and AMC(Arm Muscle Circumference) were increased during spring and summer. That of body weight, fat body weight, fat body weight ratio, waist hip ratio, and BMI(Body Mass Index were increased during fall and winter. 3. In Taeumin and Soyangin groups, the changed capacity of total body water, muscle area and BMR were increased with statistical significance. 4. Waist hip ratio of Soeumin group was reduced more than those of Taeumin, Soyangin groups with statistical significance.