Information Technology Reference
In-Depth Information
Fig. 4.
Multidimensional data model
3
Granular Structure
In this section, we will give a brief introduction to granular structure, and present
a representation of granular structure from multiview and multilevel. This repre-
sentation can be used to represent information from multi-granularity in granular
computing.
3.1
What Is Granular Structure
A central notion of granular computing is multilevel granular structures, which
consists of inter-connected and inter-acting granules, families of granules inter-
preted as levels of differing granularity, and partially ordered multiple levels
known as hierarchical structures. They are the results of a structured under-
standing, interpretation, representation, and description of a real-world problem
or system. Granular structures provide structured descriptions of a system or a
problem under consideration.
Granular computing emphasizes on structures. The study of granular com-
puting depends crucially on granular structures that represent reality through
multilevel and multiview. It seems that hierarchical granular structure is a good
candidate for developing a theory of granular computing.
3.2
Representation of Granular Structure
In granular computing, we usually represent a problem from one particular angle
or point-of-view with multiple levels of granularity by a hierarchy. However, the
conceptualization of a problem through multiple hierarchies (i.e., multiview) and
multilevel in each hierarchy is general and flexible. A complete understanding
of a problem requires a series of granular structures that should reflect multiple
views with multiple levels [16,22]. Thus, granular structures need to be modeled
as multiple hierarchies and multiple levels in each hierarchy. That is, granular
structures should reflect multiview and multilevel in each view. But there has
no effective model to represent granular structure in existing literature.
