KOMPSAT-3/3A 영상 기반 하천의 탁도 산출 연구

김다희,원유준,한상명,한향선,Kim, Dahui,Won, You Jun,Han, Sangmyung,Han, Hyangsun 대한원격탐사학회 2022 大韓遠隔探査學會誌 Vol.38 No.6

Turbidity, the measure of the cloudiness of water, is used as an important index for water quality management. The turbidity can vary greatly in small river systems, which affects water quality in national rivers. Therefore, the generation of high-resolution spatial information on turbidity is very important. In this study, a turbidity retrieval model using the Korea Multi-Purpose Satellite-3 and -3A (KOMPSAT-3/3A) images was developed for high-resolution turbidity mapping of Han River system based on eXtreme Gradient Boosting (XGBoost) algorithm. To this end, the top of atmosphere (TOA) spectral reflectance was calculated from a total of 24 KOMPSAT-3/3A images and 150 Landsat-8 images. The Landsat-8 TOA spectral reflectance was cross-calibrated to the KOMPSAT-3/3A bands. The turbidity measured by the National Water Quality Monitoring Network was used as a reference dataset, and as input variables, the TOA spectral reflectance at the locations of in situ turbidity measurement, the spectral indices (the normalized difference vegetation index, normalized difference water index, and normalized difference turbidity index), and the Moderate Resolution Imaging Spectroradiometer (MODIS)-derived atmospheric products(the atmospheric optical thickness, water vapor, and ozone) were used. Furthermore, by analyzing the KOMPSAT-3/3A TOA spectral reflectance of different turbidities, a new spectral index, new normalized difference turbidity index (nNDTI), was proposed, and it was added as an input variable to the turbidity retrieval model. The XGBoost model showed excellent performance for the retrieval of turbidity with a root mean square error (RMSE) of 2.70 NTU and a normalized RMSE (NRMSE) of 14.70% compared to in situ turbidity, in which the nNDTI proposed in this study was used as the most important variable. The developed turbidity retrieval model was applied to the KOMPSAT-3/3A images to map high-resolution river turbidity, and it was possible to analyze the spatiotemporal variations of turbidity. Through this study, we could confirm that the KOMPSAT-3/3A images are very useful for retrieving high-resolution and accurate spatial information on the river turbidity.

무로마치 시대 초물(抄物)의 비음운미(鼻音韻尾)에 접속하는 비연탁어(非連濁語) 연구

이승영 한국일본어문학회 2018 日本語文學 Vol.77 No.-

本稿は室町時代の抄物を資料とし、鼻音に後續するカサタハ行が原則的に連濁を起こすという連濁化現象が發生しない非連濁語について考察したものである。具體的には非連濁語の前接字の鼻音韻尾と聲調との關係について考察した。その結果、まず、鼻音の後の連濁語と非連濁語を調査した結果、連濁語は170字、非連濁語は889字で, 鼻音の後、連濁を起こさない字が連濁字より4倍も多いという事實から鼻音の後でも必ずしも連濁が起こるわけではないということが明らかになった。そして、非連濁された前接字の韻尾において撥音の中でも舌內鼻音[n]がもっとも多く, 次に[ŋ]が占めている。最後に、漢字の前接字の聲調と連濁を起こす當該字の聲調に注目し用例數を調査した結果、連濁が去聲字の後、起る場合が多かった。一方、非連濁語の前接字の聲調は去聲調の漢字の數が非常に少ないことがわかった。つまり、抄物では連濁が去聲調の漢字の後、起る場合が多いという傾向がある程度確認できたが、ある一方鼻音韻尾の去聲の後にも連濁が起らない場合がもっと多いということがわかった。非連濁語の當該字の聲調は平聲を除いて上聲, 去聲, 入聲が均等に現れているので、當該字の聲調は連濁と相關關係はあまりないということがわかた。 In this study, I considered the relationship between words connecting forward nasal rhyme and tone focusing on non continuous turbidity words of Chinese words where continuous turbidity phenomenon did not occur. The results as follows. Firstly, continuous turbidity words and non continuous turbidity words followed by tone were 170 letters at continuous turbidity words and 880 letters at non continuous turbidity words. This meant the thing followed by nasal sound necessarily did not make continuous turbidity. Secondly, among repulsion, tongue nasal sound[n]was most popular and the next was [ŋ]. Lastly, the numbers of example words about tone of words connecting forward and tone with continuous turbidity, there were lots of continuous turbidity cases followed by falling tone. On the other hands, tone of non continuous turbidity words connecting forward did not have few Chinese characters. Tones of non continuous turbidity words did have little relationship with continuous turbidity of the words.

팔당호에서 수중 탁도의 일 변동과 고탁수의 입자 분포

신재기 ( Sin Jae Gi ),강창근 ( Kang Chang Geun ),황순진 ( Hwang Sun Jin ) 한국하천호수학회 2003 생태와 환경 Vol.36 No.3

Daily monitoring was conducted to elucidate the changes in turbidity and distribution of particles in the turbid water of a river-type reservoir (Paltang Reservoir) from 1999 to 2001. Water turbidity and the particle distribution of turbid water were principally affected by meteorological factors particularly rainfall patterns and hydrological factors such as inflow and outflow. The mean concentration of turbidity was constant each year, with the concentration of less than 10NTU accounting for 85%. Seasonal characteristics were remarkable, with winter and spring having <5 NTU, autumn 5~10 NTU, and summer >20NTU. Unlike hydrological changes, maximum turbidity was observed from late July to early August and continuously increased from 1999 to 2001. In particular, the maximum turbidity of reservoirs remarkably increased toward the lower part of reservoir in 2001. Discharge and turbidity increased or decreased slowly in 1999; in contrast, turbidity rapidly increased in the early rainfall period of 2000 and 2001 but later decreased as discharge increased. In the particles of turbid water, clay ingredients were more densely distributed and more dominant in all stations. Of the total particles in turbid water, clay constituted 63.9%~66.6% and silt 33.4~36.1% to account for a combined total of 98.1~100%. Sand made up less than 1.1%. The turbidity of river-type reservoir was also found to be mainly affected by the biomass of plankton in a non-rainfall period. During a rainfall period, however, the quantity and relative ratio of inorganic particles depending on the soil components affected turbidity.

탁도에 따른 음료의 미각 인지: 20, 30대 소비자를 중심으로

김태수 ( Taesu Kim ),최경아 ( Kyungah Choi ),석현정 ( Hyeon-jeong Suk ) 한국감성과학회 2017 감성과학 Vol.20 No.2

본 연구에서는 음료의 탁도와 맛의 교차-양상에 근거한 연상관계를 탐색하였다. 시각 자극물로 무채색의 막걸리와 탄산음료를 선정하였으며, 자극물은 각각 0.0625~32 g/L, 0.0078~4 g/L 범위 내에서 인지적 등간격을 이룰 수 있도록 열 단계로 나누어 제작하였다. 시각적 관능 평가 실험에서는 `단맛`, `짠맛`, `쓴맛`, `신맛`, `마시고 싶은` 기본 미각형용사와 더불어, 막걸리와 관련된 `누룩향이 나는`, `술맛이 나는`, `산뜻한` 특징 미각 형용사와 탄산음료와 관련된 `부드러운`, `톡 쏘는`, `인공적인` 특징 미각 형용사를 선별하여 리커트 3점 척도로 평가하였다(N=35). 실험 결과 기본 미각에 대한 판단에 있어 막걸리는 탁도가 증가함에 따라 기본 맛이 더욱 강하게 느껴지는 반면, 탄산음료의 경우 `신맛`에서만 양의 상관관계가 관찰되었다. 특히 막걸리의 `마시고 싶은` 척도는 4.6~20 g/L 범위에서 가장 높이 관찰됐는데, 이는 시판되는 막걸리 탁도 범위와 일치하여 기억 탁도의 영향을 확인할 수 있었다. 음료 별 미각 형용사에 대해서는 `산뜻한` 맛과 `인공적인` 맛을 제외하고 두 음료 모두 탁도와 강한 양의 상관관계를 보였다. 본 연구의 결과를 바탕으로 음료의 미각적 경험을 공유할 때 탁도를 활용한다면, 각 음료가 추구하는 맛을 보다 효율적으로 소비자에게 전달할 수 있을 것으로 예상된다. This research investigated the cross-modal correspondence between the turbidity and taste of beverages. For an empirical study, we employed two types of achromatic beverages: rice wine and a soft drink. The turbidity of each drink varied between 0.0625~32 g/L, and 0.0078~4 g/L, respectively, and the stimuli were prepared in ten levels according to cognitive turbidity. In the study, participants (N=35) rated each drink stimulus using a 3-point Likert scale with regard to five basic tastes: sweet, salty, bitter, sour, and preferred. In addition, six specific tastes were included that deliberately describe rice wine and the soft drink. Three were yeasty, alcoholic, and astringent for the rice wine, and the other three were creamy, bubbly, and syrupy for the soft drink. Based on participants` assessments, the turbidity of rice wine is highly positively correlated with all five basic tastes. In contrast, the turbidity of the soft drink was positively correlated with sour only. Concerning preference, the most preferred turbidity of rice wine was 4.6~20 g/L, which is close to the turbidity of existing products on the market. Furthermore, except for astringent and syrupy, all tastes were influenced by the turbidity, which implies the potential of turbidity as a new visual parameter to communicate the taste experience of beverages.

Py_STPS모형과 관측자료를 활용한 탁도역추적기법 개발

여홍구,이남주 응용생태공학회 2023 Ecology and resilient infrastructure Vol.10 No.4

차별적 특징을 갖지 않는 탁도 측정자료에 대한 역추적기법을 개발하고자 지천의 상류와 하류에 위치한 수질자동측정점에서측정된 실시간 탁도자료와 Py_STPS모형을 사용하여 지천의 유입탁도를 예측하는 세 가지 탁도역추적기법을 비교하였다. 유하시간을고려한 탁도부하량 단순보존 방법, 유하시간을 고려한 상류경계의 유량을 하류경계의 유량으로 사용하는 방법, 탁도 유발물질의거동특성을 반영하기 위해 내부반응률을 도입한 방법 세 가지 탁도 역추적기법을 적용하였다. 세 가지 역추적모형의 적용 결과, 내부반응률을 도입한 역추적기법의 결과가 가장 우수함을 확인할 수 있었다. In order to develop a backtracking technique for turbidity measurement data without discriminatory characteristics, three turbidity backtracking techniques for predicting inflow turbidity of a stream were compared using real-time turbidity data measured at automatic water quality measurement points located upstream and downstream of the stream and the Py_STPS model. Three turbidity backtracking techniques were applied: 1) simple preservation method of turbidity load considering flow time, 2) a method of using the flow rate at the upstream boundary considering the flow time as the flow rate at the downstream boundary, 3) method of introducing internal reaction rate to reflect the behavior characteristics of turbidity-causing substances. As a result of applying the three backtracking models, it was confirmed that the backtracking technique that introduced the internal reaction rate had the best results.

Reduction in turbidity of Indian lakes through satellite imagery during COVID-19 induced lockdown

Ashish Joshi,Shefali Agrawal 대한공간정보학회 2022 Spatial Information Research Vol.30 No.6

The lakes of India are getting significantly polluted due to the rapid growth of industries, plastics, and anthropogenic waste. Due to the non-functioning of the industries and human activities during the COVID-19 pandemic lockdown, industrial and other waste going to the lakes was significantly reduced. Moreover, with the reduction of human activities and tourism in the cities and lakes, anthropogenic pollution in the lakes was also reduced. Turbidity is the key indicator of water pollution in the lakes. It has a direct relationship with surface water reflectance and can be estimated through satellite imagery. In this paper, the relative comparison of turbidity values of five Indian lakes in the Rajasthan state was done through Satellite imagery of Sentinel-2 during the pre-lockdown and lockdown period. The relative turbidity is also calculated through reflectance values of Satellite images and then the empirical method is applied to the reflectance values of the red band of Sentinel-2 & Landsat-8 data to estimate the turbidity. Relative comparisons of turbidity values estimated through satellite imagery during the pre-lockdown and lockdown period showed that the turbidity of lakes was reduced in Kaylana Lake (49.6%), Fatehsagar Lake (55.4%), Pichola Lake (54.3%), Rajsamand Lake (58.3%), and Man Sagar Lake (44.8%) during the lockdown period. Spectral curve analysis also showed that there was a decrease in the surface water reflectance in all five lakes and this indicates the reduction in the turbidity of the water during the lockdown period.

Investigation of the Performance of Chitosan as a Coagulant for Flocculation of Local Clay Suspensions of Different Turbidities

Madhukar V. Jadhav,Yogesh S. Mahajan 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.2

In the present research, the effectiveness of chitosan as a natural coagulant for turbidity removal was investigated by the use of jar test. Tests were carried out on synthetic turbid water prepared from local clay, with high (314.4 NTU), medium (146.8 NTU) and low (34.2 NTU) turbidity. Experiments were also performed with chitosan as a coagulant aid. Consequence of pH, effect of settling time on residual turbidity was also studied. In present Research New Technique was tried which adopts two sequent treatments that used coagulation, flocculation and sedimentation processes under certain operating conditions. Results show that chitosan produces an appreciable removal of turbidity at approximately neutral pH. With conventional process maximum removal of turbidity was 61.9,84.1 and 94.0% with residual turbidities of 13.0, 23.3 and 18.8 NTU for low, medium and high turbid water at dose of 1.5 mg/L. In the experiments with chitosan as a coagulant aid, the results were very promising; the residual turbiditities recorded were 8.6, 4.8 and 5.8 NTU for initial turbidities of 34.2, 146.8 and 314.4 NTU. The experimental results of present study proved that the turbidity removal efficiency of new technique was superior than that of conventional process which meets WHO drinking water guidelines. By this technique removal efficiency has increased from 5 to 28% at settling time of 30 minutes with around 75% saving in alum dose. Also sludge produced was less voluminous and readily biodegradable. There was minor change in pH of treated water. Floc formed with chitosan was coarse and readily settleable.

Effects of Main Shaft Velocity on Turbidity and Quality of White Rice in a Rice Processing System

조병효,강태환,원진호,강신형,이희숙,한충수 한국농업기계학회 2017 바이오시스템공학 Vol.42 No.1

Purpose: The purpose of this study is to analyze turbidity and quality characteristics of white rice as a function of main shaft blast velocity and to verify the optimum processing conditions in the cutting type white rice processing system (CTWRPS). Methods: Sindongjin, one of the rice varieties, which used to be produced in Gimje-si, Jeollabuk-do, in 2015, was used as the experimental material. Turbidity and quality characteristics of white rice were measured at three different main shaft blast velocities: 25, 30, and 35 m/s. The amount of test material used for a single experiment was 20 kg, and after processing, whiteness was found to be 42.5±0.5, following which, turbidity and quality characteristics were measured. Results: Turbidity decreased with increase in the shaft blast velocity, and as a result, was lowest at 35 m/s of shaft blast velocity among all the other experiment velocities. The trend of cracked rice ratios was similar to the turbidity. Broken rice ratio turned out to be less than 2.0% in all the test conditions. In the first stage of processing, the processing pressure decreased as the main shaft blast velocity increased. Additionally, in the second stage of processing, the processing pressure was at its lowest value at the main shaft blast velocity of 35 m/s. Energy consumption, too, decreased as the main shaft blast velocity was increased. Conclusions: From the above results, it is concluded that the main shaft blast velocity of 35 m/s is best for reducing turbidity and producing high quality rice in a CTWRPS.

해수의 염 농도와 탁도가 전기, UV 및 전기+UV 공정의 Artemia sp. 불활성화에 미치는 영향

김동석 ( Dong-seng Kim ),박영식 ( Young-seek Park ) 한국환경과학회 2019 한국환경과학회지 Vol.28 No.3

This study was conducted to investigate the effect of salt concentration and turbidity on the inactivation of Artemia sp. by electrolysis, UV photolysis, electrolysis+UV process to treat ballast water in the presence of brackish water or muddy water caused by rainfall. The inactivation at different salt concentrations (30 g/L and 3 g/L) and turbidity levels (0, 156, 779 NTU) was compared. A decrease in salt concentration reduced RNO (OH radical generation index) degradation and TRO (Total Residual Oxidant) production, indicating that a longer electrolysis time is required to achieve a 100% inactivation rate in electrolysis process. In the UV process, the higher turbidity results in lower UV transmittance and lower inactivation efficiency of Artemia sp. Higher the turbidity resulted in lower ultraviolet transmittance in the UV process and lower inactivation efficiency of Artemia sp. A UV exposure time of over 30 seconds was required for 100% inactivation. Factors affecting inactivation efficiency of Artemia sp. in low salt concentration are in the order: electrolysis+UV > electrolysis > UV process. In the case of electrolysis+UV process, TRO is lower than the electrolysis process, but RNO is more decomposed, indicating that the OH radical has a greater effect on the inactivation effect. In low salt concentrations and high turbidity conditions, factors affecting Artemia sp. inactivation were in the order electrolysis > electrolysis+UV > UV process. When the salt concentration is low and the turbidity is high, the electrolysis process is affected by the salt concentration and the UV process is affected by turbidity. Therefore, the synergy due to the combination of the electrolysis process and the UV process was small, and the inactivation was lower than that of the single electrolysis process only affected by the salt concentration.

Effects of Main Shaft Velocity on Turbidity and Quality of White Rice in a Rice Processing System

( Byeong-hyo Cho ),( Tae-hwan Kang ),( Jin-ho Won ),( Shin-hyeong Kang ),( Hee-sook Lee ),( Chung-su Han ) 한국농업기계학회 2017 바이오시스템공학 Vol.42 No.1

Purpose: The purpose of this study is to analyze turbidity and quality characteristics of white rice as a function of main shaft blast velocity and to verify the optimum processing conditions in the cutting type white rice processing system (CTWRPS). Methods: Sindongjin, one of the rice varieties, which used to be produced in Gimje-si, Jeollabuk-do, in 2015, was used as the experimental material. Turbidity and quality characteristics of white rice were measured at three different main shaft blast velocities: 25, 30, and 35 m/s. The amount of test material used for a single experiment was 20 kg, and after processing, whiteness was found to be 42.5±0.5, following which, turbidity and quality characteristics were measured. Results: Turbidity decreased with increase in the shaft blast velocity, and as a result, was lowest at 35 m/s of shaft blast velocity among all the other experiment velocities. The trend of cracked rice ratios was similar to the turbidity. Broken rice ratio turned out to be less than 2.0% in all the test conditions. In the first stage of processing, the processing pressure decreased as the main shaft blast velocity increased. Additionally, in the second stage of processing, the processing pressure was at its lowest value at the main shaft blast velocity of 35 m/s. Energy consumption, too, decreased as the main shaft blast velocity was increased. Conclusions: From the above results, it is concluded that the main shaft blast velocity of 35 m/s is best for reducing turbidity and producing high quality rice in a CTWRPS.