IFAC LSS'98, Large Scale Systems: Theory and Applications, July 15-17, 1998, Rio
Patras, Greece
73
FUZZY COGNITIVE MAPS MODELLING SUPERVISORY LARGE SCALE
CONTROL SYSTEMS
Chrysostomos D. Stylios, Voula C. Georgopoulos* and Peter P. Groumpos
Laboratory for Automation and Robotics, Department of Electrical and Computer
EngineeringUniversity of Patras, Rion 26500, GREECE
*School of Electrical Engineering and Computer Science, Ohio University, Athens, OH
45701,USA
Abstract: This paper investigates the implementation of a hybrid methodology, which
combines fuzzy logic and neural networks, Fuzzy Cognitive Map (FCM), for the
modeling of the supervisor of Large Scale Systems. The description and the
construction of Fuzzy Cognitive Map will be extensively examined and it will be
proposed a model for the supervisor. There is an oncoming need for more autonomous
and intelligent systems, especially in Large Scale Systems and the application of Fuzzy
Cognitive Map for the modeling of the Supervisor may contribute in the development of
more autonomous systems. Copyright © 1998 IFAC.
Keywords: Modeling, Supervisory Control, Cognitive Systems
1. INTRODUCTION
Modern systems are characterized as large-scale
systems with a variety of variables and factors. For
complex dynamical systems, conventional methods
have a limited contribution in modeling and
controlling such systems. New methods are proposed
for complex systems, which will utilize existence
knowledge, human experience, will have learning
capabilities and will have advanced characteristics
such as failure detection and identification qualities.
In this paper a new methodology, Fuzzy Cognitive
Map (FCM), is proposed for modeling systems
which may contribute to the effort for more
intelligent control methods. A Fuzzy Cognitive Map
draws a causal picture to represent the model and
behavior of system, within this representation,
concepts of FCM interact according to imprecise
rules and the operation of the complex large scale
system is simulated.
Fuzzy Cognitive Map is a symbolic representation of
the description and modeling of the system. It
consists of concepts, that illustrate different aspects
in the behavior of the system and these concepts
interact each other showing the dynamics of the
system (Kosko, 1986). The human experience and
knowledge on the operation of the system is behind a
Fuzzy Cognitive Map, as a result of the method by
which it is constructed, i.e., using human experts
that know the operation of system and its behavior in
different circumstances. FCMs describe the behavior
of a system in terms of concepts, each concept
represents a state or a characteristic of the system
(Dickerson and Kosko, 1994). FCMs illustrate the
whole system by a graph showing the cause and
effect along concepts, and are a simple way to
describe the system’s behavior in a symbolic
manner, exploiting the accumulated knowledge of
the system.
Fuzzy Cognitive Map (FCM) Theory, the methods
that it uses to describe and model the behavior of a
system and its application in the modeling the
supervisor of large-scale systems are examined.
(Stylios, et al., 1997). Fuzzy Cognitive Maps have
been used for decision analysis, management science
and operations research (Craiger, et al., 1996). The
objective here is to focus on the use of FCM in
modeling systems and show how appropriate FCMs
are to exploit the knowledge and experience which
has been accumulated for years on the operation of a
complex plant. These technologies are crude analogs
of systems that exist in human and animal systems
and have their origins in behavioral phenomena
related to these beings (Medsker, 1995). So, FCM
represents knowledge in a symbolic manner and
relates states, events and inputs in an analogous to