Equivalence of $q$-bosons using the exponential phase operator
  Various forms of the $q$-boson are explained and their hidden symmetry revealed by transformations using the exponential phase operator. Both the one-component and the multicomponent $q$-bosons are discussed. As a byproduct, we obtain a new boson algebra having a shifted vacuum structure and define a global operatal $U(1)$ gauge transformation. 
S. U. Park(Jeonju Univ.)