Application of interval type-2 fuzzy neural networks to predict short-term traffic flow

This paper presents a new prediction model based on interval type-2 fuzzy neural network (IT2FNN) and self-organising learning algorithm. Unlike traditional intelligent prediction models, whose structure and parameters must be predetermined by expert experience or professional knowledge, the IT2FNN model determines its own form by the self-organising structure identification and parameter optimisation algorithm. In the structure identification stage, the hierarchical clustering algorithm which includes lower-layer subtractive clustering and upper-layer FCM clustering is employed to determine the size of the IT2FNN predictor. Then, in the parameters optimisation stage, the steepest gradient descent algorithm is also utilised to optimise the free parameters. Finally, two groups normalised traffic flow data, which came from the 3rd ring freeway, Beijing and I880 urban freeway, California are employed to train and evaluate the IT2FNN predictor. Experiment results have illustrated its effectiveness.