• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.309-316
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• 2022

Advances in technology have improved people's lives comfortably and have developed more easily, safely and simply. We usually turn on hot water to set the temperature of the water in the bathroom and gradually adjust the temperature to find the temperature we want with our skin. In this situation, I thought, "What if there is a device that can see the temperature of water with my eyes and help with the interior of the bathroom while including a safe system," and tried to create a system that values stability. For example, if a child accidentally changes the temperature of the water to high temperature while washing, he or she can get burned. And the biggest purpose is to secure better safety by adding LCDs and LEDs so that we can visually know the temperature before feeling it tactilely. As a result of the experiment, there was no error between the temperature detected by the water temperature sensor and the temperature displayed on the LCD, and no error occurred up to 27 cm in the distance measurement experiment using the ultrasonic sensor. There has been an error of about 2% since 28cm or older, but there is no significant inconvenience in using it within the category of faucets.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.103-113
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• 2023

The river confluence is a section in which two rivers with different topographical and hyrodynamic characteristics are combined into one, and it is a section in which rapid flow, inflow of sediments, and hydrological topographic changes occur. In the confluence section, the flow of fluid occurs due to the difference in density due to the type of material or temperature difference, which is called a density flow. It is necessary to accurately measure and observe the confluence section including a certain section of the main stream and tributaries in order to understand the mixing behavior of the water body caused by the density difference. A comprehensive analysis of this water mixture can be obtained by obtaining flow field and flow rate information, but there is a limit to understanding the mixing of water bodies with different physical properties and water quality characteristics of rivers flowing with stratigraphic flow. Therefore, this study attempts to grasp the density flow through the water temperature distribution in the confluence section. Among the extensive data of the river, vertical data and water surface data were acquired, and through this, the stratification phenomenon of the confluence was to be confirmed. It was intended to analyze the mixed pattern of the confluence by analyzing the water mixing pattern according to the water temperature difference using the vertical data obtained by measuring the repair volume by installing the ADCP on the side of the boat and measuring the real-time concentration using YSI. This study can supplement the analysis results of the existing water quality measurement in two dimensions. Based on the comparative analysis, it will be used to investigate the current status of stratified sections in the water layer and identify the mixing characteristics of the downstream section of the river.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.193-193
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• 2015

오염원과 취수원이 인접한 위치에 존재하는 국내 하천 같은 경우 취수 시설의 안전한 관리를 위하여 오염물의 2차원 혼합 거동에 대한 연구가 필요하다. 하천에서의 오염물 혼합 거동을 분석하기 위하여 일반적으로 농도와 분산 정보 수집을 위한 추적자 실험을 수행해왔다. 기존에 수행된 추적자 실험들은 형광염료, 방사선 물질, 고형 물질 등과 같은 추적자를 인위적으로 주입하여 사용하였다. 그러나 수온, 전기전도도(electrical conductivity), 이온화 물질 등과 같은 자연 추적자(natural tracers)를 이용하는 추적자 실험은 인공추적자 물질을 대체할 수 있는 방안으로서, 기존 추적자 실험과 비교하여 경제적, 환경적인 효과와 하폭이 넓은 중규모 이상의 하천에서도 수행할 수 있다는 장점을 가지고 있다. 본 연구에서는 진천천과 금호강이 합류하는 낙동강 중류 구간에서 횡혼합 연구를 위하여 전기 전도도 추적 실험을 수행하였다. 강정고령보 직하류에서 낙동강 좌안쪽에서 합류하는 금호강과 진천천의 경우 인근 공업단지와 하폐수처리장으로부터 많은 비점오염원과 점오염원이 유입된다. 두곳의 지류에서 모두 높게 측정되었던 전기전도도를 자연 추적자로 선택하였다. 지류의 경우 전기전도도를 측정할 수 있는 센서를 측정 지점에 설치하여 측정하였으며, 본류인 낙동강의 경우 정해진 측선을 따라 센서가 고정된 보트를 이동하며 데이터를 취득하였다. 지류인 금호강과 진천천의 경우, 합류 전 전기전도도의 농도의 횡분포는 균일한 분포를 나타냈으며 농도의 평균값은 합류 전 낙동강 본류의 기저농도 보다 더 높은 값을 나타내었다. 지류 합류 이후의 낙동강 본류에서는 지류로부터 유입된 오염물질로 인하여 횡방향으로 불균등한 전기전도도 농도 분포를 나타내었으며 오염물질이 점점 하류 쪽으로 이동하면서, 횡방향 농도경사의 크기가 줄어들었다. 유관모멘트법을 농도곡선에 적용하여 횡방향 분산계수를 산정하였다. 산정된 횡분산계수의 값은 Rutherford (1994)가 제안한 분산계수의 범위에 포함되는 것으로 나타났다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.311-318
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• 2021

Underwater, signals are transmitted by sound waves. Sound waves are transmitted through a multipath, either directly or through reflection, due to the variety of underwater environmental characteristics. In such diverse and complex underwater environments, tests must be conducted to determine the extent of the hazard from the survivability and pitfalls of submarines by measuring the underwater radiated noise. Usually, the sound source level measurement of underwater radiated noise should be made within the closest point (CPA: Closest Point of Approach) ± a few meters between the measurement sensor and the submarine. In this study, FDOA and TDOA methods were proposed to estimate the underwater source range. A simulation based on the underwater channel model confirmed the performance of the proposed method.

• Smart Media Journal
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• v.11 no.9
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• pp.56-63
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• 2022

Recently, the frequency and range of algae occurrence in major rivers and lakes are increasing due to the increase in water temperature due to climate change, the inflow of excessive nutrients, and changes in the river environment. Abnormal algae include green algae and red algae. Green algae is a phenomenon in which blue-green algae such as chlorophyll (Chl-a) in the water grow excessively and the color of the water changes to dark green. In this study, a 3D virtual world of digital twin was built to monitor and control water quality information measured in ecological rivers and lakes in the living environment in real time from a remote location, and a sensor measuring device for water quality information based on the Internet of Things (IOT) sensor. We propose to build a smart water environment service platform that can provide algae warning and water quality forecasting by predicting the causes and spread patterns of water pollution such as algae based on AI machine learning-based collected data analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.27-27
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• 2022

본 연구는 본 연구에서는 내륙에 위치한 하천(백제보)과 호소(남양호)를 대상으로 수체반사도를 활용하여 유역특성에 따른 반사도의 변화를 확인하고 Chlorophyll-a(Chl-a)의 농도를 추정하고자 하였다. 각 유역별 특성분석을 위해 제원자료, 토지피복도 및 11개(수소이온농도, 용존산소, BOD, COD, 부유물질, 총질소, 총인, 수온, 전기전도도 및 Chlorophyll-a)의 수질인자 자료를 구축하였다. 백제보는 2016-2017년 유인항공기에 탑재된 초분광센서를 이용하여 반사도를 측정하였고, 남양호는 2020-2021년 초분광센서가 탑재된 Drone과 Sentinel-2 MSI영상으로부터 반사도를 측정하였으며 두 유역 모두 촬영 범위에 대하여 현장샘플링을 실시하였다. 유역특성, 수질인자간 상관성 및 밴드별 상관성 분석을 실시하였다. 수질인자 간 상관성 분석 결과 Chl-a와 광학적 특징이 있는 SS, TOC가 상관성이 높게 나타났으며, 반사도의 경우 Chl-a가 고농도일수록 Near-Infrared, Blue 파장과 상관성이 높게 나타났다. 해당 분석결과를 기반으로 각 유역에 대해 Chl-a Machine-learning 기법과 원격탐사자료를 이용하여 Chl-a의 농도를 산정하였으며 백제보, 남양호 각각 결정계수(R²) 0.80, 0.88의 성능을 보였다. 추후 고해상도 광학위성영상을 통해 유역특성을 고려한 광범위한 지역 규모의 Chl-a의 시공간적 분석이 가능할 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.55 no.11
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• pp.931-939
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• 2022

In Korea, about two-thirds of the precipitation is concentrated in the summer season, so the problem of turbidity in the summer flood season varies from year to year. Concentrated rainfall due to abnormal rainfall and extreme weather is on the rise. The inflow of turbidity caused a sudden increase in turbidity in the water, causing a problem of turbidity in the dam reservoir. In particular, in Korea, where rivers and dam reservoirs are used for most of the annual average water consumption, if turbidity problems are prolonged, social and environmental problems such as agriculture, industry, and aquatic ecosystems in downstream areas will occur. In order to cope with such turbidity prediction, research on turbidity modeling is being actively conducted. Flow rate, water temperature, and SS data are required to model turbid water. To this end, the national measurement network measures turbidity by measuring SS in rivers and dam reservoirs, but there is a limitation in that the data resolution is low due to insufficient facilities. However, there is an unmeasured period depending on each dam and weather conditions. As a sensor for measuring turbidity, there are Optical Backscatter Sensor (OBS) and YSI, and a sensor for measuring SS uses equipment such as Laser In-Situ Scattering and Transmissometry (LISST). However, in the case of such a high-tech sensor, there is a limit due to the stability of the equipment. Therefore, there is an unmeasured period through analysis based on the acquired flow rate, water temperature, SS, and turbidity data, so it is necessary to develop a relational expression to calculate the SS used for the input data. In this study, the AEM3D model used in the Water Resources Corporation SURIAN system was used to improve the accuracy of prediction of turbidity through the turbidity-SS relationship developed based on the measurement data near the dam outlet.

• Korean Journal of Environmental Biology
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• v.19 no.2
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• pp.107-112
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• 2001

A tissue biosensor was developed for the continuous determination of $Na^+$ channel blockers. The proposed sensor was applied to the determination of Na+ channel blockers in seaweed. It was found that $Na^+$ channel blocker content displayed seasonal variation; it was high from February to April and decreased thereafter (May - August). From these results the present proposed method may be used for high sensitive determination of $Na^+$ channel blockers contained in the seaweed organisms and environments. Therefore, it may be important to monitor $Na^+$ channel blocker content of seaweed throughout the year.

• Journal of Digital Contents Society
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• v.9 no.4
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• pp.707-715
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• 2008

The ocean ecosystem and the marine farms were damaged after latest oil spill in Taean. They suffered heavily due to the expansion of the red tide on the coast and the sudden changes in water temperature. We should develop the way to deal with various factors to reduce the damage. In this paper, real time data with which are supplied us through many kinds of sensors on measure equipments will be processed to the visualized shape. Simple numeric data and 2D graph will be changed 2D or 3D graphic objects and animations using WPF, a new effect method in user interface area. This visualization system for environmental data shows us various pictures and offers multimedia data communication.

• Korean Journal of Remote Sensing
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• v.26 no.2
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• pp.109-114
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• 2010

This paper studies the origin of low back-scattering area appeared on the SAR image taken on the coastal waters off the southeast coast of Korea on July 5, 2000. Cold waters were frequently observed during summer on this coastal waters, and quasi-simultaneously taken AVHRR and SeaWiFS images also showed cold surface waters and high concentration of chlorophyll-a, respectively. By synergetic analysis of multi-sensor satellite images, it is strongly suggested that the cold and nutrient rich upwelling waters caused the high phytoplankton density and high biological activities in the water producing natural films for low back-scattering.