  This paper investigates the decentralized stabilization problem for a class
of interconnected systems in the presence of non-triangular structural
uncertainties and time-varying parameters, where each subsystem exchanges
information only with its neighbors and only intermittent (rather than
continuous) states and input are to be utilized. Thus far to our best
knowledge, no solution exists priori to this work, despite its high prevalence
in practice. Two globally decentralized adaptive control schemes are presented
based on the backstepping technique, the first one is developed in a continuous
fashion by combining the philosophy of the modified congelation of variables
based approach with the special treatment of non-triangular structural
uncertainties, which avoids the derivative of time-varying parameters and
eliminates the limitation of the triangular condition, thus largely broadens
the scope of application. By making use of the important property that the
partial derivatives of the constructed virtual controllers in each subsystem
are all constant, the second scheme is developed through directly replacing the
states in the preceding scheme with the triggered ones. Consequently, the
non-differentiability of the virtual control stemming from intermittent state
feedback is completely obviated. The internal signals under both schemes are
rigorously shown to be globally uniformly bounded with the aid of several novel
lemmas, while the stabilization performance can be enhanced by appropriately
adjusting design parameters. Moreover, the inter-event intervals are ensured to
be lower-bounded by a positive constant. Finally, numerical simulation verifies
the benefits and efficiency of the proposed method.
