motions is used to predict future behavior. This prediction is based 

 on statistical evaluation of the time history of the event and must be 

 made "on the spot". A special purpose computer is valuable in this regard. 



It may be said that a special purpose computer has the following 

 advantages : 



1. Permits monitoring of all analysis results by the project 

 manager . 



2. Permits change of computational program, even during an analysis. 



3. Assists in modifying test programs. 



4. May be used aboard ship. 



The special purpose computer, in this case the analog energy spectrum 

 analyzer, is the heart of the SEADAC; the other components (tape recorder 

 and plotter) are auxiliary equipment necessary to its performance. 



This paper describes the SEADAC and is intended to be an operational 

 guide to project managers who can only derive the maximum benefit from the 

 SEADAC through an understanding of its philosophy and mechanics. The 

 SEADAC is only a data handling and computational tool, and is not respon- 

 sible for the quality of the results. Problems such as sampling variability, 

 confidence bands, and stationarity of data must be resolved by the project 

 engineer. The design of the data analysis procedure is also the responsi- 

 bility of the project engineer; the material in this report will assist 

 in formulating certain subjective decisions in this regard. 



A photograph of the SEADAC appears as the frontispiece. 



