International Journal of Computational Intelligence Research (IJCIR)

Volume 2, Number 1 (2006)


Achieving compatible numeral handwriting recognition rate by 

a simple activation function

Brüderle Daniel
Kirchhoff Institute for Physics, Ruprecht-Karls University, INF 227, 69120 Heidelberg, Germany

Sunat Khamron
Department of Computer Engineering, Mahanakorn University, Cheum-Sampan Road, Nong-Chok, Bangkok, Thailand 10530

Chiewchanwattana Sirapat
Department of Computer Science, KhonKaen University, Khon Kaen, Thailand 40002

Lursinsap Chidchanok, Siripant Suchada
AVIC Research Center, Department of Mathematics, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330, Thailand


Most of the supervised neural networks for numeral handwriting recognition employ the sigmoidal activation function to generate the outputs. Although this function performs rather well, its computational time as well as its hardware realization is costly and complicated. Here, we introduce a simple activation function in forms of a recursive piecewise polynomial function as an activation function. The accuracy of recognition can be adjusted according to the parameters of the function. In addition a new risk function measuring the discrepancy between the correct and estimated classification of the network is also presented to improve the performance. The proposed activation function and the risk function can achieve the same accuracy compatible with that from the sigmoidal function when tested with the benchmark data set.

Key words
activation function, handwriting recognition, risk function, supervised neural network.