A Throwdown Machine for Telephone Traffic Studies

Existing analytical m e t h o d s are i n a d e q u a t e for investigating m a n y statistical problems in which a large n u m b e r of variables a n d their interactions m u s t be considered. T h e problem of evaluating t h e p e r f o r m a n c e a n d traffic capacity of a large a u t o m a t i c telephone switching s y s t e m is one example. Others involve logistics, air a n d highway traffic control, a n d certain phases of m i l i t a r y a n d n a v a l strategy. All these require t h e assimilation of large quantities of d a t a , processing t h e d a t a according to certain procedures which are often empirical, a n d producing final information f r o m which p e r f o r m a n c e of t h e system or t h e excellence of t h e procedures can be judged. These problems fall in t h e general category of " s y s t e m s e v a l u a t i o n . " T h e t y p e s of systems considered are those t h a t are capable of a large n u m b e r of variations depending on t h e n a t u r e of t h e i n p u t d a t a , a n d m u s t be judged on a statistical basis. One m e t h o d of s t u d y m i g h t be to operate a n d observe an a c t u a l system. T h e r e are a n u m b e r of objections to this. O p e r a t i o n m a y be so slow t h a t the accumulation of sufficient d a t a m a y require excessive time or, as in t h e case of a telephone switching system, so rapid t h a t it is impractical to m a k e the necessary observations. O p e r a t i n g t h e s y s t e m u n d e r controlled conditions in these cases m a y be 292