  Itoyama-Tokura type USp matrix model is discussed. Non-Abelian Berry's phases
in a T-dualized model of IT model were reconsidered. These phases describe the
higher dimensional monopoles; Yang monopole and nine-dimensional monopole. They
are described by the connections of the BPST instanton on S^4 and the
Tchrakian-GKS instanton on S^8, respectively. As a preparation to understand
their effect in original zero-dimensional model, we consider partition function
of simplified matrix models. We compute partition functions of SU, SO and USp
reduced matrix models. Groups SO and USp appear in low energy effective
theories of string against orientifold background. In this evaluation we chose
different poles from that of Moore-Nekrasov-Shatashvili and our previous
result. The position of poles explain branes' and the orientifold's
configurations. There is a brane which is sitting on the orientifold in the
SO(2N) model, while in USp(2N) and SO(2N+1) model there are no branes on the
orientifold. The grand partition functions of these models are considered. They
follow to linear second order ordinary differential equations and their
singularities are q=0,\infty. Their solutions can be analytically continued to
whole q plane. We show the expectation values of the number N of A and C cases
as examples. There is an ambiguity coming from the problem on sign. Grand
partition functions with minus sign give effective actions which have cusp
singularities.
