1、ARTIFICIAL NEURALNETWORKS TECHNOLOGYA DACS State-of-the-Art ReportContract Number F30602-89-C-0082(Data values suchas the average, the largest, the smallest, the ORed values, the ANDed values,etc. Furthermore, most commercial development products allow softwareengineers to create their own summing f
2、unctions via routines coded in ahigher level language (C is commonly supported). Sometimes the summingfunction is further complicated by the addition of an activation functionwhich enables the summing function to operate in a time sensitive way.Either way, the output of the summing function is then
3、sent into atransfer function. This function then turns this number into a real outputvia some algorithm. It is this algorithm that takes the input and turns it intoa zero or a one, a minus one or a one, or some other number. The transferfunctions that are commonly supported are sigmoid, sine, hyperb
4、olic tangent,etc. This transfer function also can scale the output or control its value viathresholds. The result of the transfer function is usually the direct output ofthe processing element. An example of how a transfer function works isshown in Figure 2.2.4.This sigmoid transfer function takes the value from the summationfunction, called sum in the Figure 2.2.4, and turns it into a value betweenzero and one.
