It has been stated in psychology that human brain arranges information
in a way that improves efficiency in performing common tasks, for
example, information about our spatial environment is conveniently
structured for efficient route finding. On the other hand, in
computational sciences, the use of hierarchical information is well
known for reducing the complexity of solving problems. This book studies
hierarchical representations of large-scale space and presents a new
model, called Multi-AH-graph, that uses multiple hierarchies of
abstraction. It allows an agent to represent structural information
acquired from the environment (elements such as objects, free space,
etc., relations existing between them, such as proximity, similarity,
etc. and other types of information, such as colors, shapes, etc). The
Multi-AH-graph model extends a single hierarchy representation to a
mUltiple hierarchy arrangement, which adapts better to a wider range of
tasks, agents, and environments. We also present a system called
CLAUDIA, which is an implementation of the task-driven paradigm for
automatic construction of multiple abstractions: a set of hierarchies of
abstraction will be "good" for an agent if it can reduce the cost of
planning and performing certain tasks of the agent in the agent's world.
CLAUDIA constructs multiple hierarchies (Multi-AH-graphs) for a given
triple, trying to optimize their "goodness".