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| Titel |
Integrated versus isolated scenario for prediction dissolved oxygen at progression of water quality monitoring stations |
| VerfasserIn |
A. Najah, A. El-Shafie, O. A. Karim, O. Jaafar |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 15, no. 8 ; Nr. 15, no. 8 (2011-08-29), S.2693-2708 |
| Datensatznummer |
250012935
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| Publikation (Nr.) |
 copernicus.org/hess-15-2693-2011.pdf |
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| Zusammenfassung |
| This study examined the potential of Multi-layer Perceptron Neural Network
(MLP-NN) in predicting dissolved oxygen (DO) at Johor River Basin. The river
water quality parameters were monitored regularly each month at four
different stations by the Department of Environment (DOE) over a period of
ten years, i.e. from 1998 to 2007. The following five water quality
parameters were selected for the proposed MLP-NN modelling, namely;
temperature (Temp), water pH, electrical conductivity (COND), nitrate
(NO3) and ammonical nitrogen (NH3-NL). In this study, two
scenarios were introduced; the first scenario (Scenario 1) was to establish
the prediction model for DO at each station based on five input parameters,
while the second scenario (Scenario 2) was to establish the prediction model
for DO based on the five input parameters and DO predicted at previous
station (upstream). The model needs to verify when output results and the
observed values are close enough to satisfy the verification criteria.
Therefore, in order to investigate the efficiency of the proposed model, the
verification of MLP-NN based on collection of field data within duration
2009–2010 is presented. To evaluate the effect of input parameters on the
model, the sensitivity analysis was adopted. It was found that the most
effective inputs were oxygen-containing (NO3) and oxygen demand
(NH3-NL). On the other hand, Temp and pH were found to be the least
effective parameters, whereas COND contributed the lowest to the proposed
model. In addition, 17 neurons were selected as the best number of neurons
in the hidden layer for the MLP-NN architecture. To evaluate the performance
of the proposed model, three statistical indexes were used, namely;
Coefficient of Efficiency (CE), Mean Square Error (MSE) and Coefficient of
Correlation (CC). A relatively low correlation between the observed and
predicted values in the testing data set was obtained in Scenario 1. In
contrast, high coefficients of correlation were obtained between the
observed and predicted values for the test sets of 0.98, 0.96 and 0.97 for
all stations after adopting Scenario 2. It appeared that the results for
Scenario 2 were more adequate than Scenario 1, with a significant
improvement for all stations ranging from 4 % to 8 %. |
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