11/21 AN INTRODUCTION TO CYBERNETICS 



interaction between several regulations. Thus a signalman may 

 have to handle several trains coming to his section simultaneously. 

 To handle any one by itself would be straightforward, but here the 

 problem is the control of them as a complex whole pattern. 



This case is in fact still covered by the basic formulation. For 

 nothing in that formulation prevents the quantities or states or 

 elements in D, R, T, or E from being made of parts, and the parts 

 interrelated. The fact that "i)" is a single letter in no way implies 

 that what it represents must be internally simple or unitary. 



The signalman's "disturbance" D is the particular set of trains 

 arriving in some particular pattern over space and time. Other 

 arrangements would provide other values for D, which must, of 

 course, be a vector. The outcomes E will be various complex 

 patterns of trains moving in relation to one another and moving 

 away from his section. The acceptable set 17 will certainly include a 

 component "no collision" and will probably include others as well. 

 His responses R will include a variety of patterns of movements of 

 signals and points. T is what is given — the basic matters of geo- 

 graphy, mechanics, signalling techniques, etc., that lead determinately 

 from the situation that has arisen and his reaction pattern to outcome. 



It will be seen therefore that the basic formulation is capable, in 

 principle, of including cases of any degree of internal complexity. 



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