Existence and stability of periodic solutions of delayed cellular neural networks

We use the continuation theorem of coincidence degree theory and Liapunov function to study the existence and stability of positive periodic solutions for cellular neural networks (CNNs) with distributed delays dxidt=-bi(t)xi(t)+∑j=1naij(t)fj(xj(t))+∑j=1nbij(t)fj(xj(ζij(t,xj(t))))+Ii(t),i=1,2,…,nand cellular neural networks (CNNs) with state-dependent delays dxidt=-bi(t)xi(t)+∑j=1naij(t)fj(xj(t))+∑j=1nbij(t)fj∫0∞kij(u)xj(t-u)du+Ii(t),i=1,2,…,n.