  A convenient and widely used way to study the turbulent plasma in the solar
corona is to do statistics of properties of events (or structures), associated
with flares, that can be found in observations or in numerical simulations.
Numerous papers have followed such a methodology, using different definitions
of an event, but the reasons behind the choice of a particular definition (and
not another one) is very rarely discussed. We give here a comprehensive set of
possible event definitions starting from a one-dimensional data set such as a
time-series of energy dissipation. Each definition is then applied to a
time-series of energy dissipation issued from simulations of a shell-model of
magnetohydrodynamic turbulence as defined in Giuliani and Carbone (1998), or
from a new model of coupled shell-models designed to represent a magnetic loop
in the solar corona. We obtain distributions of the peak dissipation power,
total energy, duration and waiting-time associated to each definition. These
distributions are then investigated and compared, and the influence of the
definition of an event on statistics is discussed. In particular, power-law
distributions are more likely to appear when using a threshold. The sensitivity
of the distributions to the definition of an event seems also to be weaker for
events found in a highly intermittent time series. Some implications on
statistical results obtained from observations are discussed.
