problems of machine learning, systems which exhibit learning behavior. In designing a system, if the a priori infor­ mation required is unknown or incompletely known, one approach is to design a system which is capable of learning the unknown infor­ mation during its operation. The learned information will then be used to improve the system's performance. This approach has been used in the design of pattern recognition systems, automatic control systems and system identification algorithms. If we naturally extend our goal to the design of systems which will behave more and more intelligently, learning systems research is only a preliminary step towards a general concept of integrated intelligent systems. One example of this class of systems is the intelligent robot, which integrates pattern recognition. learning and problem-solving into one intelligent system.