  We study a four-dimensional effective theory of the five-dimensional (5D)
gauged supergravity with a universal hypermultiplet and perturbative
superpotential terms at the orbifold fixed points. The class of models we
consider includes the 5D heterotic M-theory and the supersymmetric
Randall-Sundrum model as special limits of the gauging parameters. We analyse
the vacuum structure of the models, especially the nature of the moduli
stabilization, from the viewpoint of the effective theory.
