Adverse results caused by the overuse of smartphones can be
easily seen in today’s society. For example, pedestrians viewing
smartphone videos when crossing the street, without checking the
traffic signal, are in danger of getting hit by cars; fumbling with
one’s smartphone while driving may cause car accidents; and
elementary-school-aged children are highly likely to be addicted to
smartphone games as well as to Internet video games [5]. In
addition, students cannot concentrate in class, and the average
cost of mobile-phone usage is increasing [1].