  The increasing popularity of cell phones has made them the most personal and
ubiquitous communication devices nowadays. Typically, the ringing notifications
of mobile phones are used to inform the users about the incoming calls.
However, the notifications of inappropriate incoming calls sometimes cause
interruptions not only for the users but also the surrounding people. In this
paper, we present a data-driven approach to infer the opportune moments for
such phone call interruptions based on user's unavailability, i.e., when a user
is unable to answer the incoming phone calls, by analyzing individual's past
phone log data, and to discover the corresponding phone silent mode configuring
rules for the purpose of minimizing call interruptions in an automated
intelligent system. Experiments on the real mobile phone datasets show that our
approach is able to identify the opportune moments for call interruptions and
generates corresponding silent mode configuring rules by capturing the dominant
behavior of individual users' at various times-of-the-day and days-of-the week.
