• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.365-369
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• 2006

MODSIM 모형은 하천유역 네트워크 모형으로 최신의 네트워크 최적화 알고리즘을 적용함으로써 유역내에서 물리적 수문학적으로 그리고 수리권과 같은 제도적인 면을 동시에 고려한 물 배분이 가능하며, 네트워크 흐름 최적화 기법은 복잡한 유역 시스템의 모의 능력을 증대시켜 준다. 모형을 이용하여 링크와 노드 및 우선순위를 토대로 금강유역을 대상으로 3개의 저류노드, 57개의 비저류노드, 72개의 수요노드 및 127개의 링크로 구성된 네트워크를 구축하였다. 개발된 네트워크 모형의 적용성 평가를 위해 충청지역의 행정중심복합도시 건설전 후의 용수수급에 대해서 분석하였으며, 네트워크 설계, 우선순위의 설정, 모의운영의 시나리오 분석 등에 있어서 만족할만한 성과를 도출하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 1989.07a
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• pp.89-94
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• 1989

본 연구는 하천 수질의 종합관리를 위한 sotware 시스템과 hardware 시스템을 개발하는 것이다. Software 시스템은 하천의 오염실태 조사분석 자료를 활용하여 예측모형의 반응식과 제 계수를 도출하고, 수질변동 및 예측모형의 중요지표 수질인자들에 대한 시각적 화면 display 를 위한 그래픽 모듈과 우리나라 오염심화 하천에 알맞는 종합수질 관리용 컴퓨터 프로그램을 개발하므로서 궁극적으로 하천의 한정된 수자원의 최적 활용을 위한 정량적, 정성적 종합수질 관리 시스템을 개발하는 것이다. 또한, Hardware 시스템은 지표 수질인자들을 자동 측정하여 on line, real time 으로 운영 될수 있는 computer supported monitoring network system 과 수질관리를 위한 지역적 수질정보를 위한 network system 을 연구하므로서 control computer system 및 programmable process controllers system 을 구축하고자 한다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1338-1339
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• 2011

Recently the wind turbine generating systems are increasing world widely. This type of systems will change the nation's energy environment which largely depends on the fossil fuels. It will also bring new problems to the power industry and the customers. The expected problem is the voltage and frequency stability of the power distribution network, when a wind turbine generating system is connected to the line. It becomes necessary and important to evaluate their impact on the electrical network stability. This paper shows the electrical data measurement and analysis of a inductive wind turbine generator affecting the power quality problem of the distribution line.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.344-347
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• 2007

A interpenetrating polymer network (IPN) hydrogel, composed of chitosan (CS) and poly(diallydimethylammonium chloride) (PDADMAC) was prepared, which exhibited electrical sensitive behavior. The swelling behavior of the CS/PDADMAC SIPN hydrogel was studied by immersion of the gel into various pH buffer solutions, and their stimuli response in electric fields also investigated. In order to clarify the relationship between the equilibrium swelling ratio and bending behavior of the SIPN hydrogels, the state of water in the SIPN hydrogel was also investigated using differential scanning calorimetry (DSC).

• Nuclear Engineering and Technology
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• v.33 no.5
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• pp.457-467
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• 2001

It is well known that the performance of a fuzzy neural network strongly depends on the input features selected for its training. In its applications to sensor signal estimation, there are a large number of input variables related with an output As the number of input variables increases, the training time of fuzzy neural networks required increases exponentially. Thus, it is essential to reduce the number of inputs to a fuzzy neural network and to select the optimum number of mutually independent inputs that are able to clearly define the input-output mapping. In this work, principal component analysis (PCA), genetic algorithms (CA) and probability theory are combined to select new important input features. A proposed feature selection method is applied to the signal estimation of the steam generator water level, the hot-leg flowrate, the pressurizer water level and the pressurizer pressure sensors in pressurized water reactors and compared with other input feature selection methods.

• Journal of Korean Society on Water Environment
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• v.31 no.1
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• pp.19-28
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• 2015

The purpose of this research is reconstruction of annual precipitation based on Tree-ring series at Seorak mountain and examine its effectiveness. To do so we performed nonlinear time series characteristics test of Tree-ring series and reconstructed annual precipitation of Gangneung from 1687 to 1911 using Artificial neural network and Nonlinear autoregressive exogeneous input (NARX) model which reflects stochastic properties. As a result, Tree-ring series at Seorak Mountain shows nonlinear time series property and reconstructed annual precipitation series drawn from NARX is similar in statistical characteristics of observed annual time series.

• Journal of Communications and Networks
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• v.14 no.3
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• pp.257-266
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• 2012

A decode-and-forward two-way relay system benefits from orthogonal frequency division multiplexing (OFDM) and relay transmission. In this paper, we consider a decode-and-forward two-way relay system over OFDMwith two strategies: A joint subcarrier matching algorithm and a power allocation algorithm operating with a total power constraint for all subcarriers. The two strategies are studied based on average capacity using numerical analysis by uniformly allocating power constraints for each subcarrier matching group. An optimal subcarrier matching algorithm is proposed to match subcarriers in order of channel power gain for both transmission sides. Power allocation is defined based on equally distributing the capacity of each hop in each matching group. Afterward, a modified water-filling algorithm is also considered to allocate the power among all matching groups in order to increase the overall capacity of the network. Finally, Monte Carlo simulations are completed to confirm the numerical results and show the advantages of the joint subcarrier matching, power allocation and water filling algorithms, respectively.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.102-114
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• 2003

The objectives of the paper are to evaluate cell based pollutant loadings for different storm events, to monitor the hydrology and water quality of the Baran HP#6 watershed, and to validate AGNPS with the field data. Simplification was made to AGNPS in estimating storm erosivity factors from a triangular rainfall distribution. GIS-AGNPS interface model consists of three subsystems; the input data processor based on a geographic information system. the models. and the post processor Land use patten at the tested watershed was classified from the Landsat TM data using the artificial neural network model that adopts an error back propagation algorithm. AGNPS model parameters were obtained from the GIS databases, and additional parameters calibrated with field data. It was then tested with ungauged conditions. The simulated runoff was reasonably in good agreement as compared with the observed data. And simulated water quality parameters appear to be reasonably comparable to the field data.

• Proceedings of the Korea Water Resources Association Conference
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• 2002.05a
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• pp.59-64
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• 2002

An expert system, to assist dam managers for five dams along the Saikawa River, has been developed with a primary objective of achieving swift and accurate reservoir operation decision-makings during floods. The expert system is capable of supporting on decision-makings upon establishment of flood management procedure and release/storage planning. Furthermore, an attempt was made to improve reservoir inflow prediction models for better supporting capability. As a result, accuracy on prediction of inflow up to 7 hours ahead was improved, which is important for flood management of the five dams, using neural network. The neural network inflow prediction models were developed for each types of floods caused by frontal rainfalls, snowmelt and typhoons, after extracting relevant meteorological factors for each.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.967-968
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• 2006

This paper proposes a novel system to send images in a narrow band network and to measure water level. In order to send images in narrow band network, we use JPEG compression technique based on the difference image. The difference image is obtained by subtracting the current image from the predefined reference image. The water level is measured to make use of the camera calibration and the edge information of the received image.