  Concrete domains have been introduced in the context of Description Logics to
allow references to qualitative and quantitative values. In particular, the
class of $\omega$-admissible concrete domains, which includes Allen's interval
algebra, the region connection calculus (RCC8), and the rational numbers with
ordering and equality, has been shown to yield extensions of $\mathcal{ALC}$
for which concept satisfiability w.r.t. a general TBox is decidable. In this
paper, we present an algorithm based on type elimination and use it to show
that deciding the consistency of an $\mathcal{ALC}(\mathfrak{D})$ ontology is
ExpTime-complete if the concrete domain $\mathfrak{D}$ is $\omega$-admissible
and its constraint satisfaction problem is decidable in exponential time.
  While this allows us to reason with concept and role assertions, we also
investigate feature assertions $f(a,c)$ that can specify a constant $c$ as the
value of a feature $f$ for an individual $a$. We show that, under conditions
satisfied by all known $\omega$-admissible domains, we can add feature
assertions without affecting the complexity.
