11/14 AN INTRODUCTION TO CYBERNETICS 



regulator gives C complete control over the output, in spite of the 

 entrance of disturbing effects by way of D. Thus, perfect regulation 

 of the outcome by R makes possible a complete control over the out- 

 come by C. 



We can see the same facts from yet another point of view. If 

 an attempt at control, by C over E: 



C 



E 



is disturbed or made noisy by another, independent, input D, so 

 that the connexions are 



then a suitable regulator R, taking information from both C and D, 

 and interposed between C and T: 



may be able to form, with T, a compound channel to E that transmits 

 fully from C while transmitting nothing from D. 



The achievement of control may thus depend necessarily on the 

 achievement of regulation. The two are thus intimately related. 



Ex. 1 : From Table 11/3/1 form the set of transformations, with C as parameter, 

 that must be used by i? if C is to have complete control over the outcome. 

 (Hint: What are the operands?) 



Ex. 2 : If, in the last diagram of this section, C wants to transmit to E at 20 bits/ 

 second, and a source D is providing noise at 5 bits/second, and T is such 

 that if R is constant, E will vary at 2 bits/second, how much capacity must 

 the channel from D to R have (at least) if C's control over E is to be 

 complete? 



Ex. 3 : (Continued.) How much capacity (at least) is necessary along the chan- 

 nel from Cto Rl 



Ex. 4: (Continued.) How much along that from R to Tl 



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