• 한국환경과학회지
• /
• 제31권5호
• /
• pp.431-445
• /
• 2022

The Gwangju Stream is a major tributary of the Yeongsan River. To maintain environmental and ecological functions in the stream, the flow is secured by natural water from the Mudeung Mountain as well as waters discharged from Lake Juam and the Gwangju sewage treatment plants. A substantial amount of water is supplied into the upper reaches of Gwangju Stream from Lake Juam. To examine the ecological effects of the water input from Lake Juam on the Gwangju Stream, a field survey of phytoplankton community species and an evaluation of water properties was conducted at five stations, from station GJ1 before the inflow to station GJ5 in the lower region. Nutrient levels decreased in the vicinity of the Lake Juam inflow, suggesting that this water inflow can contribute to the reduction of eutrophication in the stream. The phytoplankton community was mainly composed of Bacillariophyceae, Chlorophyceae, and Cyanophyceae, and the community structure was similar to that of the other study sites located near the water inflow regions. The inflow of water from Lake Juam can affect water quality and the phytoplankton community over a limited area, reducing eutrophication and increasing water flow in the Gwangju Stream.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 1998년도 학술발표회 발표논문집
• /
• pp.547-551
• /
• 1998

Reaeration coefficient is the physical absorption of oxygen from the atmosphere by water. It is the most important natural means by which a stream replaces the oxygen consumed in the biodegradation of organic wastes, and the rate constant describing this process is the reaeration coefficient, It. Reaeration coefficient is the dominant parameter affecting the use of water quality model. Therefore accurate estimation of the reaeration coefficient is essential for optimum water quality management. There is several method to estimate stream reaeration coefficient. In this study, it would be concluded that SI-peak method is of practical use when applied to small stream, and CRI method is adequate to large stream.

• 한국환경과학회지
• /
• 제12권3호
• /
• pp.287-297
• /
• 2003

To investigate water quality and pollution states of rivers in Gwangju city, total of 30 water samples were taken from the main stream of Yeongsan river, Hwangryong river and Gwangju stream in dry and flood seasons. Physico-chemical characteristics of above streams according to pH-Eh and Piper's diagrams we, typically, assigned to natural river water. In the streams, BOD, COD, T-N and T-P indicating water quality mostly increase toward downstream. Notably, water qualities in area near connection between the Gwangju stream and the main stream of Yeongsan river are polluted over V level in rivers and lakes water quality standard. The pollutions are influenced by lift and agricultural foul waters from Gwangju City and farming areas around upstream branches of the Yeongsan river, reasonably. Besides, heavy metals are below the standard in those streams. So, it is considered that the streams are polluted by not industrial but life/agricultural foul waters.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2005년도 학술발표논문집
• /
• pp.330-335
• /
• 2005

This study was performed for the analysis of the variation characteristics on riverbed according to the arrangement of stream. It was monitored of the variation progress of riverbed dependent on the elapsed time after the arrangement and It was studied that the hydraulic adjustment of the riverbed caused by the variation of the riverbed. The large amount of deposit just after the construction in which the riverbed was arranged to natural form was come from the reduction of flow rate by the installed artificialities such as weirs and stone weirs and by the stones or the concrete blocks attached to the stream sides of riverbanks. This phenomenon was well consistent with the usual characteristics that the accumulation is induced on upper stream of hydraulic artificialities and the erosion is induced on down stream of hydraulic artificialities. The large reduction of the deposit 1 year later after the construction showed that the riverbed eroded considerably because of the recovery of flow amount and the rise of flow rate.

• 통합자연과학논문집
• /
• 제13권4호
• /
• pp.147-151
• /
• 2020

In this paper, we propose a method to detect concept drift by applying Convolutional Neural Network (CNN) in a data stream environment. Since the conventional method compares only the final output value of the CNN and detects it as a concept drift if there is a difference, there is a problem in that the actual input value of the data stream reacts sensitively even if there is no significant difference and is incorrectly detected as a concept drift. Therefore, in this paper, in order to reduce such errors, not only the output value of CNN but also the probability vector are used. First, the data entered into the data stream is patterned to learn from the neural network model, and the difference between the output value and probability vector of the current data and the historical data of these learned neural network models is compared to detect the concept drift. The proposed method confirmed that only CNN output values could be used to reduce detection errors compared to how concept drift were detected.

• 한국농공학회지
• /
• 제24권2호
• /
• pp.76-88
• /
• 1982

The stream morphological characteristics of a basin have important influence upon the analysis of runoff. In this study, the laws of stream morphology-the law of average stream fall and the law of least rate of potential energy expenditure-which were derived based on the analogy of entropy in thermodynamics are introduced and their validity is analysised with the data taken from the topographic maps covering the whole Geum River system. The first law is the Law of Average Stream Fall which states that under the dynamic equilibrium condition the ratio of average fall between any two different order stream in the same river basin in unity. The second law is the law of least rate of energy expenditure which states that all natural streams are intended to choose their own course of flow such that the rate of potential energy loss per unit mass of water this course is a minimum. The parameters representing the morphological characteristics of 13 tributaries in the Geum River system such as stream bifurcation ratio and stream concavity were Computed from the Horton-Strahler's laws and are used to check the law of average stream fall. The result showed that the law of average stream fall agrees reasonably well with law of Horton-Strahler. Concavity of a river basin is shown to be the determinative factor to the formation of a stream system. Concavity of a river basin is shown to be the determinative factor to the formation of a stream system. Based on Horton's Law and the law of average stream fall, longitudinal stream profiles can be calculated.

• 한국물환경학회지
• /
• 제23권3호
• /
• pp.332-338
• /
• 2007

In this study the flow duration curves for Nakdong river basin are analyzed. The TANK model is used as a hydrologic simulation model whose parameters are estimated from 8-day intervals flow data measured by NIER Nakdong River Water Environment Laboratory. As a comparison result between generated natural and present river flow, the present river flow is higher than the natural river flow in the up- and mid-stream of Nakdong river, while the present river flow is lower than the natural river flow in the down stream of Nakdong river.

• Journal of Information Processing Systems
• /
• 제17권2호
• /
• pp.399-410
• /
• 2021

Aiming at the problem that complex external variables in natural scenes have a greater impact on facial expression recognition results, a facial expression recognition method based on two-stream convolutional neural network is proposed. The model introduces exponentially enhanced shared input weights before each level of convolution input, and uses soft attention mechanism modules on the space-time features of the combination of static and dynamic streams. This enables the network to autonomously find areas that are more relevant to the expression category and pay more attention to these areas. Through these means, the information of irrelevant interference areas is suppressed. In order to solve the problem of poor local robustness caused by lighting and expression changes, this paper also performs lighting preprocessing with the lighting preprocessing chain algorithm to eliminate most of the lighting effects. Experimental results on AFEW6.0 and Multi-PIE datasets show that the recognition rates of this method are 95.05% and 61.40%, respectively, which are better than other comparison methods.

• 한국지역지리학회지
• /
• 제14권1호
• /
• pp.27-39
• /
• 2008

본 연구는 낙동강과 그 지류인 금호강에 형성된 호소성 습지의 형성과정을 밝히고자 하였다. 이를 위하여 세 시기의 지형도를 비교 분석하고 단면도를 작성하였으며, 퇴적물의 입경분포를 분석하였다. 그 결과 호소성 습지의 형성 과정을 3가지로 유형화하였다. 첫째, 샛강습지와 금강늪은 망류하천을 이루고 있는 구간에서 분류하여 흐르는 유로의 자유로운 이동 과정에서 남아 형성된 잔적호 습지이다. 둘째, 씩실늪과 낫늪은 배후산지에서 흘러나온 지류가 자연제방의 방해로 유로가 차단되어 자연제방과 평행하게 흘러 본류로 유입되는 yazoo형 습지이다. 셋째, 세천늪과 호촌늪, 진촌늪은 본류 하천의 범람으로 자연제방과 배후습지가 형성된 이후에 다음 홍수시 범람하는 본류 하천이 습지로 유입되어 형성된 범람 유입수형 습지이다.

• ALGAE
• /
• 제18권2호
• /
• pp.157-167
• /
• 2003

Effect of the effluent of the sewage and wastewater plants on the algal growth was investigated from the 19 plants located in the Nakdong river basin. Most of the samples showed high values of the algal growth potential (AGP) when they were mixed with natural river water at 20% of final concentration. At 20% of the mixing ratio, the mixed effluents of sewage and wastewater showed 3.5 and 1.8 times higher AGP than those of the natural river water. The higher AGP values are attributable to the high contents of phosphorus and ammonium in the effluent. The mixing ratio of effluents of the discharge/river flow was highest in the Kumho River (42.8%) followed by the middle of Nakdong River (22.7%), Kam Stream (13.9%), Byungsung Stream (13.3%), Yangsan Stream (7.9%), and Young River (5.4%). Comparison of the trophic state of the effluents with natural river water indicated that the effluents showed higher trophic values than natural water. Concentrations of total phosphorus, total nitrogen and conductivity in the effluents were 12.3, 4.9 and 5.3 times higher than the those found in natural river water respectively. The AGP values were highly related with the trophicity of the water especially on the concentrations of phosphate and ammonium. Toxicities of the treated sewage water, wastewater and livestock waste water tested by the luminescent bacteria, Vibrio fischerii were generally low.