• Title, Summary, Keyword: Water temperature

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Artificial Neural Network-based Real Time Water Temperature Prediction in the Soyang River (인공신경망 기반 실시간 소양강 수온 예측)

  • Jeong, Karpjoo;Lee, Jonghyun;Lee, Keun Young;Kim, Bomchul
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.12
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    • pp.2084-2093
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    • 2016
  • It is crucial to predict water temperature for aquatic ecosystem studies and management. In this paper, we first address challenging issues in predicting water temperature in a real time manner and propose a distributed computing model to address such issues. Then, we present an Artificial Neural Network (ANN)-based water temperature prediction model developed for the Soyang River and a cyberinfrastructure system called WT-Agabus to run such prediction models in an automated and real time manner. The ANN model is designed to use only weather forecast data (air temperature and rainfall) that can be obtained by invoking the weather forecasting system at Korea Meteorological Administration (KMA) and therefore can facilitate the automated and real time water temperature prediction. This paper also demonstrates how easily and efficiently the real time prediction can be implemented with the WT-Agabus prototype system.

Study on the Thermal Storage Characteristics of a Multi-capsule type LTES System -Analysis for Heat Charging and Discharging Process for Water Flow- (다관형 잠열축열장치의 축열특성연구 -물을 매체로 한 축열 및 방열과정 분석-)

  • Kim, Y.B.
    • Journal of Biosystems Engineering
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    • v.19 no.1
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    • pp.62-69
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    • 1994
  • This study was designed to seek information on the heat charging and discharging characteristics of a multi-capsule type LTES(Latent Heat of Fusion Thermal Energy Storage) system, and especially prediction equation of outlet water temperature from the system. During heat charging process, the water temperature in the LTES tank increased very slowly in comparison with a predicted one and was kept near the melting point of the PCM for about 25 minutes. During heat discharging process, the latent heat discharging period of the outlet water temperature became longer as the inlet water temperature became higher and/or mass flow rate became lower. The dimensionless temperature of the outlet water was predicted by linking three equations of ${\theta}=1.1Exp(-{\tau}/0.82)$, ${\theta}=-0.06{\tau}+0.3$, ${\theta}=0.8Exp(-{\tau}/1.4)$ ($r^2{\leq}0.88$) depending on discharging period regardless of mass flow rates on the case of the inlet water temperature at $21.5^{\circ}C$.

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Fabrication of a multi-functional one-chip sensor for detecting water depth, temperature, and conductivity (수위, 온도, 전도도 측정을 위한 다기능 One-Chip 센서의 제조)

  • Song, Nak-Chun;Cho, Yong-Soo;Choi, Sie-Young
    • Journal of Sensor Science and Technology
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    • v.15 no.1
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    • pp.7-12
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    • 2006
  • The multi-functional one-chip sensor has been fabricated to reduce output variation under various water environment. There were a temperature sensor, a piezoresistive type pressure sensor, and a electrode type conductivity sensor in the fabricated one-chip sensor. This sensor was measured water depth in the range of $0{\sim}180cm$, temperature in the range of $0{\sim}50^{\circ}C$, and salinity in the range of 0 $0wt%{\sim}5wt%$, respectively. Since the change of water depth in solution environment depends on various factors such as salinity, latitude, temperature, and atmospheric pressure, the water depth sensor is needed to be compensated. We tried to compensate the salinity and temperature dependence for the pressure in water by using lookup-table method.

Development of a Bath Assistive System with Water Temperature Monitoring to Prevent Heart Attack (수온 모니터링 기능을 탑재한 심장마비 방지용 목욕 보조 시스템)

  • Kang, So Myoung;Wei, Qun
    • Journal of Korea Multimedia Society
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    • v.22 no.2
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    • pp.242-249
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    • 2019
  • Old people and patients with cardiovascular disease could die of a heart attack in the bath with heated water for a long time. Various researches have been studied to prevent these accidents from happening such as measuring the ECG signal when taking bath. However, these devices are hard to use and the higher price is not easily accepted by the public. In this paper, a low-cost and use-friendly, real time high precision water temperature monitoring device to prevent heart attack in the bath was developed. The device with waterproof design that lets the device can float on the surface of the water, and an accurate way to make water temperature measurement method was proposed by this paper that is immerging the sensor into water with 4cm depth to measure the temperature of underwater. The manufactured device was conducted to two experiments; one was to verify the basic functions of the device, and another one was for compare the proposed device with commercial products for monitoring the water temperature in the bathtub. As the experimental results shown, the proposed device has stable performance for the water temperature measurement and communicating with laptop in wireless.

Climatological Trend of Sea Water Temperature around the Antarctic Peninsula Waters in the Southern Ocean

  • Lee, Chung-Il;Kim, Sang-Woo;Kim, Dong-Sun;Yoon, Moon-Geun
    • Journal of Environmental Science International
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    • v.21 no.2
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    • pp.125-133
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    • 2012
  • Climatological trend for the period of 1970 to 2009 in sea water temperature around the Antarctic Peninsular waters in the Southern Ocean was investigated. During the period from 1970 to 2009, sea water temperature in the top 500 m water column except 100 m increased at a rate of $0.003-0.011^{\circ}C{\cdot}yr^{-1}$, but at 100 m it decreased at a rate of $-0.003^{\circ}C{\cdot}yr^{-1}$. Although long-term trend is generally warming, there were several periods of sharp changes between 1970 and 2009. Annual mean sea water temperature between surface and 500 m except 100 m decreased from the early of 1970s to the end of 1980s, and then it increased to the end of 2000s. In the entire water column between the surface and 500 m, sea water temperature closely correlated with the El Nino events expressed as the Southern Oscillation Index(SOI), and SOI and sea water temperature have a dominant period of about 3-5 years and decade.

Seasonal Variation of Water Temperature and Dissolved Oxygen in the Youngsan Reservoir (영산호 수온과 용존산소의 계절적 변화에 관한 연구)

  • Park, Yongwoo;Cho, Kian;Cho, Cheol
    • Journal of Korean Society on Water Environment
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    • v.24 no.1
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    • pp.44-53
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    • 2008
  • To recognize the spatial and temporal variability of water temperature and dissolved oxygen in the Youngsan reservoir formed after dike construction, water temperature and dissolved oxygen data have been observed and analyzed from April, 2002 until March, 2003. As the results, certain stratifications were not distinctly observed in the Youngsan reservoir during summer, which was estimated due to the drainage characteristic from the Youngsan water gates. The yearly variation of water temperature in the Youngsan reservoir is shown seasonally ups and downs by the heat exchange between the atmosphere and the reservoir. On the other hand, dissolved oxygen and water temperature in the Youngsan reservoir have been shown inversed proportional correlation. As the calculation results of residence time and water exchange rate, it is considered that the feature of oxygen distribution is determined by the drainage characteristics caused the shortest residence time during summer, which also disturbed the formation of stratification in the Youngsan reservoir.

A Study on the Distribution of Summer Water Temperature in Wando Using Time-Series Analysis and Numerical Experiments (시계열 분석 및 수치실험을 통한 완도의 하계 수온분포)

  • Jang, Chan-Il;Jeong, Da-Woon;Kim, Dong-Sun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.2
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    • pp.188-195
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    • 2018
  • Time series analysis was conducted to identify the factors affecting short-term variation of water temperature in Wando. Spectrum analysis showed that air temperature peaks at diurnal period, while water temperature and tide level peak at both semi-diurnal and diurnal periods. Coherence between water temperature and the tide level presented 0.92 at semi-diurnal period. Numerical experiment were carried out to understand the spatio-temporal distribution of water temperature in the study area. Average water temperature difference between maximum ebb and flood was $0.3^{\circ}C$ in spring tide, but $0.13^{\circ}C$ in neap tide. The reason for the large difference in spring tide is that relatively cold water entered with strong tidal currents at flood tide and flowed out at ebb tide. Water temperature on coasts was higher than out at sea. This is because the depth in the coast is shallower than at sea, and water temperature increases rapidly due to solar radiation.

Analysis of Heat Transfer Characteristics in Response to Water Flow Rate and Temperature in Greenhouses with Water Curtain System (수막하우스의 유량 및 수온에 따른 열전달 특성 분석)

  • Kim, Hyung-Kweon;Kim, Seoung-Hee;Kwon, Jin-Kyeong
    • Protected Horticulture and Plant Factory
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    • v.25 no.4
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    • pp.270-276
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    • 2016
  • This study analysed overall heat transfer coefficient, heat transmission, and rate of indoor air heating provided by water curtain in order to determine the heat transfer characteristic of double-layered greenhouse equipped with a water curtain system. The air temperatures between the inner and outer layers were determined by the water flow rate and inlet water temperature. Higher water flow rate and inlet water temperature resulted in the increased overall heat transfer coefficient between indoor greenhouse air and water curtain. However, it was found that with higher levels of water flow rate and inlet water temperature, indoor overall heat transfer coefficient was converged about $10W{\cdot}m^{-2}{\cdot}^oC^{-1}$. The low correlation of overall heat transfer coefficient between water curtain and air within double layers was likely because the combination of greenhouse shape, wind speed and outdoor air temperature as well as water curtain affected the heat transfer characteristics. As water flow rate and inlet water temperature increased, the heat transferred into the greenhouse by water curtain also tend to rise. However it was demonstrated that the rate of heat transmission from water curtain into greenhouse with water curtain system using underground water was accounted for 22% to 28% for total heat lost by water curtain. The results of this study which quantify heat transfer coefficient and net heat transfer from water curtain may be a good reference for economical design of water curtain system.

An Experimental Study on Low-Temperature Behavior of Stratified Fluids in a Square Cavity with Upper Cooling Surface (상부에 냉각면이 있는 정방형내 이종유체의 저온거동에 관한 실험적 연구)

  • Lee, D.S.;Kim, B.C.
    • Solar Energy
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    • v.20 no.1
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    • pp.55-62
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    • 2000
  • An experimental study on the stratified fluids with water and silicon oil of same volume in the cavity with upper cooling surface was carried out to investigate the flow characteristics, heat transfer through the interface of fluids, and the applications of thermal behaviors in a square cavity. The experiments were performed with variation of initial temperature and cooling surface temperature. The temperature drop of oil was faster than that of water and freezing was initiated from the interface of oil and water and propagated downward. For the water above $4^{\circ}C$, the cooling rate was faster than that below $4^{\circ}C$ and showed almost same temperature distribution but for the water that of below $4^{\circ}C$, it showed the stable stratified temperature distribution. The lower the initial temperature and the higher the cooling surface temperature was, the longer the supercooling duration.

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Correlation and Hysteresis Analysis of Air-Water Temperature in Four Rivers: Preliminary study for water temperature prediction (우리나라 하천의 기온-수온의 상관관계 및 이력현상 분석: 미래 하천수온 변화 예측을 위한 사전검토)

  • An, Ji-Hyuck;Lee, Khil-Ha
    • Journal of Environmental Policy
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    • v.12 no.2
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    • pp.17-32
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    • 2013
  • The potential impact of water temperature on air temperature in response to recent anthropogenic global warming has been noticed. To predict climate, induced change in river aquatic environment, it is necessary to understand the thermal constrains of fish species and the timing of the projected river temperature. As a preliminary study, air-water temperature relationship was analyzed on the basis of the observed data during the time period of 2009-2011 and the number of data corresponds to 873-1083. As a result of analyzing the auto-and cross-correlation coefficient between air-water temperature, high correlation is shown (~0.9). It is also found that the correlation coefficient of air temperature is higher than that of water temperature at the lag time less than approximately 10 days. Observed data was divided into two groups to investigate hysteresis: rising limb and falling limb. For some stations there is strong evidence that hysteresis exist between air-water temperature relationships. Consequently it is recommended that seasonal hysteresis needs to be included in determining an airwater relationship.

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