ACKNOWLEDGEMENTS

I would like to express my appreciation to my thesis

advisor,

Professor

and encouragement.

D. R. Reddy, for his guidance, advice,

I am grateful to Dr. Peter E. Hart for

his helpful suggestions and to Dr, Hart and Professors John

Tenenbaum for many enlightening discussions, to Gilbert Falk for the use of Figures 3-1 and 3-2, to Karl Richard Neely for making

Pingle and available to me some of their