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Sun et al. Complex Eng Syst 2022;2:17  I http://dx.doi.org/10.20517/ces.2022.48   Page 3 of 15






















                                                  Figure 1. Framework of the paper.

               surely exponential stability are presented for highly nonlinear SSSs with time-varying delays.


               The remainder of this paper is organized as follows. An introduction of the model and important assumptions
               aregiveninSection2. TheexistenceofauniqueglobalsolutionandstabilityanalysisarepresentedinSections3.
               In Section 4, a simulation example is presented to validate our theoretical results. Finally, Section 5 concludes
               the paper.

               Note: In this paper, R + = (0, ∞), N + = 1, 2, · · · ,   , · · ·, N = N + ∪ {0} with    being a positive finite integer,
                   
                                                            
                                                                        
               R denotes the   -dimensional real space. For    ∈ R , |  | =  ( ∑      =1    2  ) 1 2  denotes the Euclidean norm of vector.
                                            √
                                                                                           
                                                 
               For any matrix    ∈ R   ×   , |  | =        denotes the trace norm of matrix   , where    is the transpose of
               matrix    and tr{  } denotes its trace. For    > 0,   ([−  , 0]; R ) denotes the space of all continuous functions
                                                                    
                                   
                                                                                  
                                                                        
                  from [−  , 0] → R with the norm ||  || = sup −  ≤  ≤0 |  (  )|, C ([−  , 0]; R ) denotes the family of all F 0-
                                                                     F 0
               measurable bounded C([−  , 0]; R )-valued random variable    = {  (  ) : −   ≤    ≤ 0}. Let (  , F , P) be a
                                              
               complete probability space with a filtration {F    }   ≥0.   (  )=(   1 (  ), · · ·,       (  )) denotes an   -dimensional F   -
                                                                                              1,2
               adapted Brownian motion, which is defined on a complete probability space. In addition, V  denotes the
                                                                    
               family of all non-negative functions   (  ,   ,   ) : [−  , ∞) × R × Γ → R +, which are first-order continuously
                                                                                          
               differentiable in    and second-order continuously differentiable in   . Let   ([−  , ∞) × R ; R + ) be the family of
                                                
               continuous functions    : [−  , ∞)×R → R +. For real numbers    and   ,   ∧   = min{  ,   },   ∨   = max{  ,   }.
               2. PRELIMINARIES
               Model descriptions and assumptions are introduced in this section. In this study, we analyzed the following
               highly nonlinear SSS with time-varying delays:
                                      (  ) =      (  ) (  ,   (  ),   (   −       ))     +      (  ) (  ,   (  ),   (   −       ))    (  ),  (1)
               with the initial value:

                                                                    
                                                                               
                                          {  (  ) : −   ≤    ≤ 0} =    ∈ C ([−  , 0]; R ),              (2)
                                                                  F 0
               where    > 0 is a constant and switching signal   (  ) : [0, ∞) → Γ = {1, 2, · · · ,   } is a piecewise constant
               function that is continuous from the right. In particular, it is a non-random function of   . For    ∈ [      ,      +1 ),
                 (  ) =       ∈ Γ, where       is the   th switching time instant and    ∈ N. For each    ∈ Γ, the mappings
                                                   
                          
                               
                                    
                                                       
                      : R × R × R → R and       : R × R × R → R   ×    are Borel-measurable functions. Compared with [13] ,
                    +
                                            +
               one of the merits of this paper is that the time delay       is merely a Borel measurable function of    and may be
               non-differentiable. Precisely, we need to impose some requirements on the time-varying delay      .
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