• Proceedings of the Korea Water Resources Association Conference
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• 1993.07a
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• pp.393-400
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• 1993

• Water for future
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• v.50 no.3
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• pp.45-51
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• 2017

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.21-28
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• 2005

The training and prediction modeling using an artificial neural network was implemented to predict the turbidity of treated water as well as to estimate the optimized feed concentration of polyaluminium chloride (PACl) in a water treatment plant. The parameters used in the input layers were pH, temperature, turbidity and alkalinity, while those in output layers were PACl and turbidity of treated water. Levenberg-Marquadt method of feedforward back-propagation perceptron in the neural network toolbox of MATLAB program was used in this study. Correlation coefficients of the training data with the measured data were 0.9997 for PACl and 0.6850 for turbidity and those of the testing data with measured data were 0.9140 for PACl and 0.3828 for turbidity, when four parameters at input layer, 12-12 nodes each at both the first and the second hidden layers, and two parameters(PACl and turbidity) at output layer were used. Although the predictability of PACl was improved, compared to that of the previous studies to use the only coagulant dose as output layer, turbidity in treated water could not be predicted well. Acquisition of more data through several years obtained with the advanced on-line measuring system could make the artificial neural network useful and practical in actual water treatment plants.

• Water Engineering Research
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• v.4 no.1
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• pp.1-17
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• 2003

A mathematical model was developed to simulate the performance of a prototype wind-powered reverse osmosis desalination system. The model consists of two sub-models operated in a series. The first sub-model is the wind-energy conversion sub-model, which has wind energy and feed water as its input and pressurized feed water as its output. The second sub-model is a reverse osmosis (RO) process sub-model, with pressurized feed water as its input and the flow and salinity of the product water or permeate as its output. Model coefficients were determined based on field experiments of a prototype wind powered RO desalination system of the University of Hawaii, from June to December 2001. The mathematical model developed by this study predicts the performance of wind-powered RO desalination systems under different design conditions. The system optimization is achieved using a linear programming approach. Based on the results of system optimization, a design guide is prepared, which can be used by both manufacturer and end-user of the wind-driven reverse osmosis system.

• Journal of Korea Port Economic Association
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• v.22 no.2
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• pp.35-60
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• 2006

This paper uses input-output techniques to analyze the impacts of the coastal and inland water transportation (CIWT) upon the Korean economy between 1990 and 2000. The impacts were identified by means of backward and forward linkages effects, production inducing and import-inducing effects, and commodity prices repercussion effects of the coastal and inland water transportation. The data of this study come from The Bank of Korea databases for Input-Output Structure of the Korean economy. The major findings in this study can, among others, be summarized: that the power of dispersion(=backward linkage effect) and the degree of sensitivity (=forward linkage effect) of CIWT are higher than those of the deep sea transportation sector and that it has higher production-inducing effect than the average of total industries, while it has lower import-inducing effect than the average of total industries.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2605-2607
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• 2000

This paper represents the construction of a PLC simulator for the level control of water and the speed control of the water cask. The level and speed processes are automatically operated by the PLC. The simulator system consists of PLC, program loader and control penal. The digital input and output units make the valves of the water cask the On or Off state. The analog input and output units control the level of water and the speed of the water cask. A LD program is used in the control language of PLC.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.6
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• pp.792-798
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• 2021

In this paper, an algorithm for determining the coagulant input rate in the drug-injection tank during the process of the water purification plant was derived through big data analysis and prediction based on artificial intelligence. In addition, analysis of big data technology and AI algorithm application methods and existing academic and technical data were reviewed to analyze and review application cases in similar fields. Through this, the goal was to develop an algorithm for determining the coagulant input rate and to present the optimal input rate through autonomous driving simulator and pilot operation of the coagulant input process. Through this study, the coagulant injection rate, which is an output variable, is determined based on various input variables, and it is developed to simulate the relationship pattern between the input variable and the output variable and apply the learned pattern to the decision-making pattern of water plant operating workers.

• Journal of Navigation and Port Research
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• v.37 no.3
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• pp.269-273
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• 2013

Underwater acoustic channels are generally recognized as one of the most difficult communication media because of the multipath propagation, dispersion, and so on. MIMO (Multiple-input multiple-output) techniques have been actively pursued in underwater acoustic communications recently to increase the data rate over the bandwidth-limited channels. The transmit diversity techniques can be applied in this case, and one of them is Alamouti's scheme. In this paper the performances of the transmit diversity technique are evaluated via experiment. Two transmitters and two receivers were used in experiment, and the experiment was performed in indoor water tank. The error rate 5~8% was confirmed in experimental results, and these are the improved values than the error rate 14.8% for SISO(Single-input single-output) channel under same data rate condition.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.451-455
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• 2001

This study was performed to examine water and nutrient balance during rice cropping period using difference fertilization paddy plot in ground water irrigation region. The experimental rice paddy consist of three plot, Treatment of Excess fertilization(TEF) and Treatment of Standard Fertilization(TSF) and Treatment of Reduce Fertilization(TRF). As result, input amount to rice paddy was almost rainfall and output was direct runoff through drainage. nutrient input amount was upper paddy in case COD and fertilization in case Total nitrogen and total phosphorus, and output was drainage in all nutrient.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.209-218
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• 2011

This study is to estimate economic damages of water shortage, especially drought. we assume scenarios of water shortage and use water input-output linear programming. The result is that economic damage is about 6.4 trillion won in the case of 10% water shortage. According to water shortage scenarios, the shadow price of water in Korea is increasing from 2,462 won to 76,902 won. This study indicates that water has a significant influence on the industrial production in Korea and provides the necessity of the climate change policy for water management.