• Title/Summary/Keyword: Water Scale Detection

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Characterization of Legionella Isolated from the Water System at Public Facilities in Chungcheongnam-do Province (충남지역 다중이용시설의 환경수계에서 분리한 레지오넬라균의 특성 분석)

  • Cheon, Younghee;Lee, Hyunah;Nam, Hae-Sung;Choi, Jihye;Lee, Dayeon;Ko, Young-Eun;Park, Jongjin;Lee, Miyoung;Park, Junhyuk
    • Journal of Environmental Health Sciences
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    • v.47 no.5
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    • pp.472-478
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    • 2021
  • Background: The Legionella case detection and notification rate have increased in public artificial water environments where people visit, including large buildings, public baths, and hospitals. Objectives: In this study, the distribution of Legionella and its epidemiologic characteristics were analyzed in the water systems of public facilities in Chungcheongnam-do Province in South Korea. Methods: Culture and PCR analysis were performed on 2,991 environmental water system samples collected from 2017 to 2019, and associations with year, facilities, seasons, and temperature of water system were statistically analyzed by using R-Studio for Windows. Descriptive data was compared using chi-square tests and independent t-tests. Results: The detection rate of Legionella increased from 3.1% in 2017 to 10.3% in 2019, appearing most frequently in the order of public baths, large-scale buildings, hospitals, and apartments. It was detected mainly in summer from June to August, over 1.0×103 CFU/L on average in 133 cases (66.5%). Lots of germs were detected in bathtub water, cooling tower water, and warm water (p<0.001), and it was detected at higher rates in the cities where multipurpose facilities were concentrated than in rural areas (p=0.018). Conclusions: This study suggests that continuous monitoring and control are required for Legionella in the water system environment of high risk facilities. Moreover, these results will be helpful to prepare efficient management plans to prevent the Legionellosis that occurs in Chungcheongnam-do Province.

Research of Water-related Disaster Monitoring Using Satellite Bigdata Based on Google Earth Engine Cloud Computing Platform (구글어스엔진 클라우드 컴퓨팅 플랫폼 기반 위성 빅데이터를 활용한 수재해 모니터링 연구)

  • Park, Jongsoo;Kang, Ki-mook
    • Korean Journal of Remote Sensing
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    • v.38 no.6_3
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    • pp.1761-1775
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    • 2022
  • Due to unpredictable climate change, the frequency of occurrence of water-related disasters and the scale of damage are also continuously increasing. In terms of disaster management, it is essential to identify the damaged area in a wide area and monitor for mid-term and long-term forecasting. In the field of water disasters, research on remote sensing technology using Synthetic Aperture Radar (SAR) satellite images for wide-area monitoring is being actively conducted. Time-series analysis for monitoring requires a complex preprocessing process that collects a large amount of images and considers the noisy radar characteristics, and for this, a considerable amount of time is required. With the recent development of cloud computing technology, many platforms capable of performing spatiotemporal analysis using satellite big data have been proposed. Google Earth Engine (GEE)is a representative platform that provides about 600 satellite data for free and enables semi real time space time analysis based on the analysis preparation data of satellite images. Therefore, in this study, immediate water disaster damage detection and mid to long term time series observation studies were conducted using GEE. Through the Otsu technique, which is mainly used for change detection, changes in river width and flood area due to river flooding were confirmed, centered on the torrential rains that occurred in 2020. In addition, in terms of disaster management, the change trend of the time series waterbody from 2018 to 2022 was confirmed. The short processing time through javascript based coding, and the strength of spatiotemporal analysis and result expression, are expected to enable use in the field of water disasters. In addition, it is expected that the field of application will be expanded through connection with various satellite bigdata in the future.

Green Algae Detection in the Middle·Downstream of Nakdong River Using High-Resolution Satellite Data (고해상도 위성영상을 활용한 낙동강 녹조탐지기법 비교 및 분석)

  • Byeon, Yugyeong;Seo, Minji;Jin, Donghyun;Jung, Daeseong;Woo, Jongho;Jeon, Uujin;Han, Kyung-soo
    • Korean Journal of Remote Sensing
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    • v.37 no.3
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    • pp.493-502
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    • 2021
  • Recently, because of changes in temperature and rising water temperatures due to increased pollution sources, many algae have been produced in the water system. Therefore, there has been a lot of research using satellite images for the generation and monitoring of green algae. However, in prior studies, it is difficult to consider the optical properties of the local water system by using only a single index, and by using medium and low-resolution satellite images to conduct large-scale algae detection, there is a problem of accuracy in narrow, broad rivers. Therefore, in this work, we utilize high-resolution images of Sentinel-2 satellites to perform green algae detection on a single index (NDVI, SEI, FGAI) and development index (NDVI & SEI, FGAI & SEI) that mixes single indices. In this study, POD, FAR, and PC values were utilized to evaluate the accuracy of green algae detection algorithms, and the FGAI & SEI index showed the highest accuracy with 98.29% overall accuracy PC.

Development of leakage test facility for leak signal characteristic analysis in water pipeline (상수도관로 누수신호의 특성 분석을 위한 누수 실험시설 개발)

  • Park, Sanghyuk;Kwak, Philljae;Lee, Hyundong;Choi, Changho
    • Journal of Korean Society of Water and Wastewater
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    • v.31 no.5
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    • pp.459-469
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    • 2017
  • A real scale leakage test facility was developed to study the leak signal characteristics of water supply pipelines, and then leak tests were carried out. The facility was designed to overcome the limited experimental circumstances of domestic water supply pipeline experimental facilities. The length of the pipeline, which was installed as a straight line, is 280m. Six pipes were installed on a 70m interval with different pipe material and diameters that are DCIP(D200, D150, D100, D80), PE(D75) and PVC(D75).The intensity of the leakage is adjusted by changing the size of the leak hole and the opening rate of ball valve. Various pressure conditions were simulated using a pressure reducing valve.To minimize external noise sources which, deteriorate the quality of measured leak signal, the facility was built at a quiet area, where traffic and water consumption by customers is relatively rare. In addition, the usage of electric equipment was minimized to block out noise and the facility was operated using manual mode. From the experimental results of measured leakage signal at the facility, it was found that the signal intensity weakened and the signal of high frequency band attenuated as the distance from the water leakage point increased.

Online Burning Material Pile Detection on Color Clustering and Quaternion based Edge Detection in Boiler

  • Wang, Weixing;Liu, Sheng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.1
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    • pp.190-207
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    • 2015
  • In the combustion engineering, to decrease pollution and increase production efficiency, and to optimally keep solid burning material amount constant in a burner online, it needs a smart method to detect the amount variation of the burning materials in a high temperature environment. This paper presents an online machine vision system for automatically measuring and detecting the burning material amount inside a burner or a boiler. In the camera-protecting box of the system, a sub-system for cooling is constructed by using the cooling water circulation techqique. In addition, the key and intelligent step in the system is to detect the pile profile of the variable burning material, and the algorithm for the pile profile tracing was studied based on the combination of the gey level (color) discontinuity and similarity based image segmentation methods, the discontinuity based sub-algorithm is made on the quaternion convolution, and the similarity based sub-algorithm is designed according to the region growing with multi-scale clustering. The results of the two sub-algoritms are fused to delineate the final pile profile, and the algorithm has been tested and applied in different industrial burners and boilers. The experiements show that the proposed algorithm works satisfactorily.

Detection of thin-layered soil using CRPT in soft soil (CRPT를 이용한 연약지반 협재층 탐지)

  • Yoon, Hyung-Koo;Kim, Joon-Han;Kim, Rae-Hyun;Choi, Yong-Kyu;Lee, Jong-Sub
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.117-125
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    • 2008
  • The detection of thin-layered soil is important in soft soils to evaluate the soil behavior. The smaller diameter cone penetrometer have been commonly used to detect the layer with increasing sensitivity. The objective of this study is to detect the thin-layered soil using cone resistance and electrical resistance. The cone resistivity penetration test (CRPT) is developed to evaluate the cone tip resistance and electrical resistance at the tip. The CRPT is a micro-cone which has a $0.78cm^2$ in projected area. The application test is conducted in a laboratory large-scale consolidometer (calibration chamber). The kaolinite, sand and water are mixed to make the specimen at the liquid limit of 46% using a slurry mixer. It takes two months for the consolidation of the specimen. After consolidation, the CRPT test is carried out. Furthermore the standard CPT results are compared with the electrical resistance measured at the tip in the field. This study suggests that the CRPT may be a useful tool for detecting thin-layers in soft soils.

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Detection of Change in Water System Due to Collapse of Laos Xe pian-Xe namnoy Dam Using KOMPSAT-5 Satellites (KOMPSAT-5 위성 영상을 활용한 라오스 세피안-세남노이 댐 붕괴에 따른 수계변화 탐지)

  • Kim, Yunjee;Lee, Moungjin;Lee, Sunmin
    • Korean Journal of Remote Sensing
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    • v.35 no.6_4
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    • pp.1417-1424
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    • 2019
  • Recently, disaster accidents have occurred frequently over the world, and disaster have been continuously studied using remote sensing due to large scale and hard-to-reach features. The collapse of Laos Xe pian-Xe namnoy dam in 2018 also caused a lot of human and economic damage. This study's purpose is to change detect water system due to the collapse of Xe pian-Xe namnoy dam in Laos and to derive areas where future flooding is expected. The water system is extracted from each image of KOMPSAT-5 before and after the dam collapse in order to quantitatively change detect in the water system. The result of the water system area increased more than 10 times after the dam collapse. In addition, it is confirmed that the newly created water system is thickly created in areas of low altitude area. This study result can be used in the future to systematize the pre-response to abnormalities and issues in existing operating dams. And then, if combined with other remote sensing data, more diverse and specific results could be obtained.

Constructing Overhauser Dynamic Nuclear Polarization-Nuclear Magnetic Resonance System Using Benchtop Electron Paramagnetic Resonance Spectrometer

  • Saun, Seung-Bo;Kim, JiWon;Han, Oc Hee
    • Journal of the Korean Magnetic Resonance Society
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    • v.22 no.2
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    • pp.34-39
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    • 2018
  • The Nuclear Magnetic Resonance (NMR) technique using Dynamic Nuclear Polarization (DNP) procedures is one of the promising techniques that enable overcoming low sensitivity problems in NMR spectroscopy. We constructed an ODNP-NMR system using a commercial benchtop EPR spectrometer. The $^1H$ NMR peak area of water in aqueous solutions of 4-hydroxy-TEMPO was enhanced more than 95 times in the ODNP-NMR experiments. Our signal enhancement results were about 55% of the previously reported result. This could be due to non-uniform microwave power over a sample and unwanted sample heating by microwave. However, this portable ODNP-NMR spectrometer will be eventually useful for site-specific detection with nano-scale spatial resolutions and molecular dynamics studies with significantly improved signal sensitivity.

DETECTION OF DUST LOADED AIRMASS IN SEAWIFS IMAGERY: AN EMPIRICAL DUST INDEX IN COMPARISON WITH MODEL-PREDICTED DUST DISTRIBUTION OVER THE PACIFIC IN APRIL,1998

  • Fukushima, H.;Schmidt, M.;Sohn, B.J.;Toratani, M.;Uno, I.
    • Proceedings of the KSRS Conference
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    • 1999.11a
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    • pp.89-94
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    • 1999
  • The paper first proposes an empirical algorithm for detecting dust-loaded airmass observed by Sea Wide Field-of-view Scanner (SeaWiFS). The proposed dust index formula is based on the curvature of the spectral reflectance estimated from the SeaWiFS band 4 (510 nm band) through band 8 (865 nm band) data, assuming "clear ocean water" reflectance. Evaluation of the algorithm is made over several typical Asian dust images including the ones over the Pacific in April, 1998, when a major dust event was reported. The study analyzes the performance and the characteristics of the algorithm by comparing the satellite-derived dust index images with contemporaneous columnar concentration of dust particles predicted by a numerical dust transport model. The comparison reveals several small-scale differences although their dust distribution patterns show good agreement generally.

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Implantable and Flexible GaN LED for Biomedical Applications

  • Lee, Geon-Jae
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.17.1-17.1
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    • 2011
  • Inorganic III-V light emitting diodes (LEDs) have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to conventional incandescent lamps and OLED. However, due to the brittle property of bulk inorganic semiconductor materials, III-V LED limits its applications in the field of high performance flexible electronics. This seminar introduces the first flexible and implantable GaN LED on plastic substrates that is transferred from bulk GaN on Si substrates. The superb properties of the flexible GaN thin film in terms of its wide band gap and high efficiency enable the dramatic extension of not only consumer electronic applications but also the biosensing scale. The flexible white LEDs are demonstrated for the feasibility of using a white light source for future flexible BLU devices. Finally a water-resist and a biocompatible PTFE-coated flexible LED biosensor can detect PSA at a detection limit of 1 ng/mL. These results show that the nitride-based flexible LED can be used as a type of implantable LED biosensor and as a therapy tool.

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