  We formulate and analyze a generic sequential resource access problem arising
in a variety of engineering fields, where a user disposes a number of
heterogeneous computing, communication, or storage resources, each
characterized by the probability of successfully executing the user's task and
the related access delay and cost, and seeks an optimal access strategy to
maximize her utility within a given time horizon, defined as the expected
reward minus the access cost. We develop an algorithmic framework on the
(near-)optimal sequential resource access strategy. We first prove that the
problem of finding an optimal strategy is NP-hard in general. Given the
hardness result, we present a greedy strategy implementable in linear time, and
establish the closed-form sufficient condition for its optimality. We then
develop a series of polynomial-time approximation algorithms achieving
$(\epsilon,\delta)$-optimality, with the key component being a pruning process
eliminating dominated strategies and, thus maintaining polynomial time and
space overhead.
