Fig 1.
Basic structure of ANN model.
Fig 2.
Langat River basin [47].
Reprinted from [47] under a CC BY license, with permission from PLOS ONE, original copyright 2017.
Table 1.
Statistical analysis of the data for both stations.
Fig 3.
Plot of monthly average interpolated data of nitrate-N and ammonia-N.
Fig 4.
Plot of monthly average data of rainfall, water level and discharge.
Table 2.
Different input and internal parameters for different ANN models.
Fig 5.
Flow chart for the model selection for nitrate-N at Lui station.
Fig 6.
Taylor diagram for nitrate-N (Lui).
Fig 7.
Taylor diagram for ammonia-N (Kajang).
Table 3.
Optimum ANN models for Lui and Kajang stations.
Fig 8.
Comparison of mean square error for different input vectors for nitrate-N at station Lui.
Fig 9.
Comparison of mean square error for different training data division percentage for nitrate-N at station Lui.
Fig 10.
Plot of variation of mean square error against number of nodes in hidden layers for nitrate-N at station Lui.
Fig 11.
Plot of variation of mean square error against number hidden layers for nitrate-N at station Lui.
Fig 12.
Plot of variation of testing mean square error against spread values for general regression model for nitrate-N at station Lui.
Fig 13.
Plot of variation of testing mean square error against spread values for RBFNN model for nitrate-N at station Lui.
Fig 14.
Plot of variation of mean square error against epochs for nitrate-N at station Lui.
Fig 15.
Relative error percentage plot for optimum selected model.
Fig 16.
Observed versus predicted plot for optimum selected models.
Fig 17.
Average uncertainty of different models.
Table 4.
Comparison of current study results with literature.