  Wireless Sensor Networks (WSNs) are being used extensively today in various
domains. However, they are traditionally deployed with applications embedded in
them which precludes their re-use for new applications. Nowadays,
virtualization enables several applications on a same WSN by abstracting the
physical resources (i.e. sensing capabilities) into logical ones. However, this
comes at a cost, including an energy cost. It is therefore critical to ensure
the efficient allocation of these resources. In this paper, we study the
problem of assigning application sensing tasks to sensor devices, in
virtualized WSNs. Our goal is to minimize the overall energy consumption
resulting from the assignment. We focus on the static version of the problem
and formulate it using Integer Linear Programming (ILP), while accounting for
sensor nodes' available energy and virtualization overhead. We solve the
problem over different scenarios and compare the obtained solution to the case
of a traditional WSN, i.e. one with no support for virtualization. Our results
show that significant energy can be saved when tasks are appropriately assigned
in a WSN that supports virtualization.
