FOREWORD 



It is a great honor for me to deliver the Sixth David W. Taylor 

 Lecture series and I would like to express my sincere thanks to the David 

 Taylor Naval Ship R&D Center for the kind arrangement which has enabled me 

 to have such an opportunity. 



The subject which I am going to talk about is the problem of 

 engineering. It is not the problem of mathematics, although recent 

 progress in technology depends greatly upon mathematical theories, and 

 mathematics has become an indispensable aid to solve engineering problems 

 nowadays . 



