  Knowledge plays a central role in human and artificial intelligence. One of
the key characteristics of knowledge is its structured organization. Knowledge
can be and should be presented in multiple levels and multiple views to meet
people's needs in different levels of granularities and from different
perspectives. In this paper, we stand on the view point of granular computing
and provide our understanding on multi-level and multi-view of knowledge
through granular knowledge structures (GKS). Representation of granular
knowledge structures, operations for building granular knowledge structures and
how to use them are investigated. As an illustration, we provide some examples
through results from an analysis of proceeding papers. Results show that
granular knowledge structures could help users get better understanding of the
knowledge source from set theoretical, logical and visual point of views. One
may consider using them to meet specific needs or solve certain kinds of
problems.
