COMMENT AND CORRECTION ON "STABILITY CRITERUA FOR TIME-DELAY SYSTEMS WITH UNCERTAINTY"

In a recent paper(YANG Kai-yang et al, Information and Control,Vol.30 no.5,pp: 474-476,2001),several stability conditions for single uncertain delay system were proposed by using comparision theorem and some properties of the matrix norm and matrix measure. Some unreasonable conditions were used, so their results were incorrect. This paper gives a suffcient criterion on delay-dependent stability of linear time-varying delay systems with uncertainty in terms of defferential function theory and some properties of the matrix exponent.