Cataloged from PDF version of article.In this thesis, we consider a robust capacity expansion-routing problem with
uncertain demand. Given a network with source and demand nodes and a capacity
budget, the capacity expansion problem is related to the determination of
the arcs on which additional capacity will be installed in order to minimize the
overall routing cost while satisfying the demand of the nodes. We make use of
the Robust Counterpart (RC) approach in the literature in order to make capacity
installation and routing decisions. RC approach is important since it does
not allow any constraint violation for any realization of the uncertainty and such
approaches are often necessary in engineering applications in real life.
We apply the classical RC formulation to our problem that results in a simple
one-stage model. The two-stage version of the RC formulation, namely the
Adjustable Robust Counterpart (ARC), is also applicable to our problem. The
formulation of the ARC is given but since it is not computationally tractable, an
approximation to ARC developed recently, namely Affinely Adjustable Robust
Counterpart (AARC) formulation, is applied to our problem and solved.
The efficiencies of the RC formulation and AARC formulation are tested via
two different sets of numerical studies in the experimental part. The main model
that allows capacity installation in continuous amounts as well as two extensions
that make use of the modular capacity approach are used in the experimental
study. The computational experiments illustrate that AARC approach provides
robust solutions at a much cheaper cost in terms of objective function value when
compared to RC approach. In addition the loss of optimality due to application
of AARC formulation is minor.Kahramanoğlu, İbrahim EvrenM.S
