• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1474-1478
• /
• 2007

수문 및 수질자료는 일정한 기준에 의한 관측치를 시계열 자료로 기록하거나 전송할 때 다양한 형태의 오차가 발생하게 되며 또한 수문 및 수질자료를 관측하는 측정기기의 고장과 유지관리 등의 어려움으로 다양한 형태의 결측 자료가 발생하고 있다. 이와 더불어 수문 및 수질자료는 시공간적 변동성이 크며 비선형성이 강한 특성을 갖고 있다. 이러한 수문 및 수질 자료를 이용하여 모형을 구축할 경우 다양한 형태의 잡음에 대한 검증 및 잡음저감이 필수적 요건이라 할 수 있다. 따라서 본 연구에서는 영산강 유역의 본류부를 대표하는 나주지점에 대한 유출량과 총유기탄소(TOC) 농도 및 TOC 부하량 예측모형을 개발하였으며, 이를 위한 방법으로는 잡음저감을 위하여 웨이블렛 변환과 인공신경망을 적용하였다. TOC 부하량 자료는 유출량과 TOC 자료간의 함수로서 표현이 가능함에 따라 유출량 및 TOC 자료가 결측되었을 경우 역함수에 의한 계산으로 결측 자료에 대한 보간이 가능하다. 따라서 본 연구의 주안점은 잠음 저감 및 인공신경망에 의해 최적화된 예측 모형이 결측된 유출량과 TOC 자료에 대한 역함수로 정도있는 유출량과 TOC 자료 생성 가능성을 검토하고자 한다. 본 연구의 적용 결과, 유출량 자료가 결측되었을 경우 TOC 및 TOC 부하량 예측으로 유출량 자료에 대한 간접추정 및 결측 자료에 대한 보간의 정도를 평가한 결과 $R^2$는 0.99 이상의 값을 보였다. 또한, TOC 자료가 결측되었을 경우 역시 $R^2$는 비교적 우수한 0.97 이상의 값을 보였다. 따라서 본 연구에서 개발한 유출량 및 TOC, TOC 부하량 예측모형의 개발은 정도있는 유출량 및 TOC 수질 자료의 생성이 가능할 것으로 기대된다.한 물순환 해석을 할 수 있는 기반을 확보 하였으며, 가용한 장 단기간의 관측자료와 물수지 분석 연산식의 추정치를 바탕으로 관측자료에 의한 물수지 분석을 수행하였다. 분석 결과로 산지 소하천 유역인 설마천 시험유역의 각 수문요소의 물이동간의 정량적인 값을 알 수가 있었으며, 앞으로 추가적이고 지속적인 수문모니터링이 운영되고 물순환 해석 모형에 의한 검증이 수행된다면 정량적인 물순환 관계를 규명할 수 있을 뿐만 아니라 이와 관련된 수문요소기술을 확보할 수 있을 것이다.절한 타협과 조정을 필요로 한다. 그러나 절제의 한계를 넘어선다고 생각되거나, 조정의 노력이 불가능하거나, 실패했을 때 폭력적인 행동으로 나타나게 된다. 리차즈(I.A Richards)는 분노와 공포는 일단 겉잡을 수 없는 경향이 있다고 하면서 오늘날 폭력에 대한 요구가 일상의 정서 생활에 있어, 억압을 통한, 빈곤함을 반영하고 있지 않은지 생각해봐야 할 것이라고 충고한다. 조성 가이드라인(안)을 제시하였다.EX>$\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기소의 위치가 완전히 삭제되어 있다. 이러한 현상은 첫째, 15세기 중엽 경제적 태평과 함께 백자의 수요 생산이 증가하자 군신의 변별(辨別)과 사치를 이유로 강력하게 규제하여 백자의 확대와 발전에 걸림돌이 되었다. 둘째, 동기(銅器)의 대체품으로 자기를 만들어 충당해야할 강제성 당위성 상실로 인한 자기수요 감

• The Journal of Engineering Geology
• /
• v.16 no.4 s.50
• /
• pp.373-379
• /
• 2006

We investigated the relationship of the organic pollutant index in wastewater where the high percentages of an organic load to a water body was found. Measuring of TOC was to identify the relationship with COD and BOD which were used already. The correlation coefficient (r) of TOC/COD, BOD/COD and TOC/BOD were effected by the types of industry such as paper, textile, chemical, food and metal industries. In food industry it was found that the highest correlation coefficient (r) of TOC/COD, BOD/COD and TOC/BOD as 0.967, 0.969 and 0.990, respectively. There is low correlation coefficient in many cases. Hence it was impossible that the use of TOC for the water standard or monitoring instead of COD and BOD directly. However it can be used as alternative index to management a water process in the case of waste water where there was found high correlation coefficient of TOC/ COD, BOD/COD and TOC/BOD. It was sure that the water quality of river body can be protected if we use these the relationship among organic index.

• Journal of Korean Society on Water Environment
• /
• v.35 no.6
• /
• pp.520-538
• /
• 2019

In this study, it was proposed that a method of setting the target water quality for TOC using the watershed model and the load duration curves to manage non-biodegradable organics in the total water load management system. To simulate runoff and water quality of the watershed, the HSPF model is used which is appropriate for urban and rural areas. Additionally, the load duration curve is used to reflect the variable water quality correlated with various river flow rates in preparing the TMDL plans in the U.S. First, the model was constructed by inputting the loads calculated from the pollutant sources in 2015. After the calibration and verification process, the water quality by flow conditions was analyzed from the BOD and TOC simulation results. When the BOD achieved the target water quality by inputting the target year loads for 2020, the median and average values of TOC were proposed for the target water quality. The provisional method of TOC target water quality for the management of non-biodegradable organics, which is one of the challenges of the total water load management system, was considered. In the future, it is expected to be used as basic data for the conversion of BOD into TOC in the total water load management system.

• Journal of Environmental Science International
• /
• v.29 no.7
• /
• pp.691-702
• /
• 2020

Carbon biomass of plankton community, Total Organic Carbon (TOC) and Chlorophyll a (chl.a) concentration were examined in the SeoNakdong river from January to December in 2014, to assess composition of phyto- and zoo-plankton variation, to certify the correlation between chl.a and TOC and to determine the level of contribution of plankton carbon content to TOC in the reservoir-river ecosystem. The correlation level between TOC and chl.a was low in the year 2014 but exceptionally was highly correlated only during the period with cyanobacterial bloom. The high level of contribution of plankton carbon content to TOC was attributed to cyanobacterial carbon biomass from May to November and to Cladocera carbon biomass from March to May, November and December despite of its low abundance. These results suggest that there were inter-relationships between phytoplankton, zooplankton and TOC and also subtle consistency of their properties through the year. These patterns should be discussed in relation to the physiochemical and biological characteristics of the environment, as well as to allochthonous organic matters from non-point pollution sources.

• Journal of Korean Society on Water Environment
• /
• v.29 no.5
• /
• pp.618-624
• /
• 2013

This study was conducted to suggest the concentration distribution of organic matters in 348 tributaries of Nakdong River, and to review the validity of the conversion of organic matter indexes. The average concentration of organic matters in the tributaries was TOC 2.4 mgC/L, DOC 2.1 mgC/L, COD 1.0 mgC/L, respectively. DOC ratio to TOC is 87% and COD ratio is 44%. First tributaries shows higher organic pollution than second tributaries. The correlation between TOC and COD was relatively high as 0.796 (p < 0.01, n = 670). Based upon these results, a regression analysis was conducted. The results showed that TOC concentration was 2.5 times higher than COD concentration. In conclusion, it is appropriate to use TOC for the management of all organic matters. Furthermore, there is a need to build organic matter-related Databases for more rivers so as to establish TOC standards and manage the water quality.

• Journal of Korean Society of Water and Wastewater
• /
• v.30 no.3
• /
• pp.241-251
• /
• 2016

As the Enforcement Ordinance of Environmental Policy Act was revised in 2013, total organic carbon(TOC) was added as an indicative parameter for organic matter in Water and Aquatic Ecosystem Environmental Criteria. Under these imminent circumstances, a regulatory standard is needed to achieve the proposed TOC limitation control water quality from the public sewage treatment plants(PSTWs). This study purposes to present the determination method for TOC effluent limitation at the PSTWs. Therefore we investigate the TOC effluent limitation of foreign countries such as EU, Germany and USA, and analyse the effluent water qualities of PSTWs. In using these TOC data, we review apprehensively the statistics-based, the technology-based, and the region(water quality)-based determination method of TOC effluent limitation for PSTWs.

• Journal of Korean Society on Water Environment
• /
• v.22 no.5
• /
• pp.952-957
• /
• 2006

The present study applied wavelet transform and artificial neural networks (ANNs) for the prediction of daily TOC data. TOC data were transformed into denoised data by the wavelet transform and the noise-reduced data were used for the prediction model by artificial neural networks. For the application of wavelet transform, Daubechies wavelet of order 10 ('db10') was used as a basis function and decomposed the TOC data up to fifth level with five detail components and one approximation component. ANNs were calibrated with the input data of the segregated TOC data corresponding to the details from second to fifth level and the approximation. Consequently, the ANNs model for the prediction of daily TOC data showed the best result when it had seventeen hidden nodes in its layer.

• Journal of Wetlands Research
• /
• v.16 no.1
• /
• pp.153-160
• /
• 2014

TOC environmental standard was established to understand the pollution level accurately and to improve the water quality. It was found that the relationship between COD and TOC showed a significant coefficient($R^2$=0.639) in four lakes for drinking water located in Nakdong River basin. The relationship between COD and TOC($R^2$=0.774) was higher with respect to the elevated concentration level when the data was added. Resulting in the oxidation(C) was $62{\pm}8%$ regardless of COD concentrations. It was difficult to find a significant difference by lakes. The result showed the similar organic property in study lakes. It was necessary to evaluate the level of organic matters in consideration of characteristics and utilization of lakes to use COD data wisely until TOC data be accumulated sufficiently.

• Journal of Environmental Science International
• /
• v.28 no.6
• /
• pp.571-579
• /
• 2019

In this study, monthly average values of BOD, COD, and TOC observed for 10 years (2008-2017) in the Nam River were estimated, and monthly variations of BOD, COD, and TOC were analyzed. Monthly average COD was always higher than monthly average BOD; monthly average TOC was high from June to September when rainfall was high. Monthly correlation coefficients between BOD and COD ranged from 0.57 to 0.94, those between BOD and TOC from 0.45 to 0.93, and those between COD and TOC from 0.75 to 0.93. The correlation coefficients were high from November to February when rainfall was low. Regression analyses for monthly average water quality data of the Nam River classified into dry season (October to April) and wet season (May to September) were conducted. Correlation coefficients were higher in the dry season than those in the wet season, and the determination coefficients of linear regression functions for BOD and COD with TOC were also higher in the dry season than those in the wet season. From this study, it can be concluded that it is appropriate to use monthly data to analyze the correlations among BOD, COD, and TOC in the stream. To analyze the relationship between TOC flowing into the stream and BOD/COD, it was found that seasonal characteristics should be considered.

• The Mathematical Education
• /
• v.63 no.2
• /
• pp.369-385
• /
• 2024

With the advancement of digital technology, a variety of digital materials are being utilized in education. For their appropriate use of digital resources, teachers need to be able to evaluate the quality of digital resource and determine the suitability for teaching. This study explored how preservice teachers evaluate TocToc-Math, an Artificial Intelligence (AI)-based math support system. Based on an evaluation framework developed through prior research, preservice teachers evaluated TocToc-Math with evidence-based criteria, including content quality, pedagogy, technology use, and mathematics curriculum alignment. The findings shows that preservice teachers positively evaluated TocToc-Math overall. The evaluation tendencies of preservice teachers were classified into three groups, and the specific characteristics of each factor differed depending on the group. Based on the research results, we suggest implications for improving preservice teachers' evaluation abilities regarding the use of digital technology and AI in mathematics education.