  Large parameter space explorations are among the most time consuming yet
critically important tasks in many fields of modern research. ExpoCloud enables
the researcher to harness cloud compute resources to achieve time and
budget-effective large-scale concurrent parameter space explorations.
  ExpoCloud enables maximal possible levels of concurrency by creating compute
instances on-the-fly, saves money by terminating unneeded instances, provides a
mechanism for saving both time and money by avoiding the exploration of
parameter settings that are as hard or harder than the parameter settings whose
exploration timed out. Effective fault tolerance mechanisms make ExpoCloud
suitable for large experiments.
  ExpoCloud provides an interface that allows its use under various cloud
environments. As a proof of concept, we implemented a class supporting the
Google Compute Engine (GCE). We also implemented a class that simulates a cloud
environment on the local machine, thereby facilitating further development of
ExpoCloud.
  The article describes ExpoCloud's features and provides a usage example. The
software is well documented and is available under the MIT license.
