Pattern Classification

• The hidden unit y 1 computes the boundary:x 1 + x 2 + 0.5 = 0≥ 0 ⇒ y 1 = +1< 0 ⇒ y 1 = -1• The hidden unit y 2 computes the boundary:x 1 + x 2 -1.5 = 0≤ 0 ⇒ y 2 = +1< 0 ⇒ y 2 = -1• Output unit emits z 1 = +1 if and only if y 1 = +1 and y 2 = +1Using the terminology of computer logic, the units arebehaving like gates, where the first hidden unit is an ORgate, the second hidden unit is an AND gate, and the outputunit implementsz k = y 1 AND NOT y 2 = (x 1 OR x 2 ) and NOT(x 1 AND x 2 ) =x 1 XOR x 2which provides the nonlinear decision of fig. 6.114Pattern Classification, Chapter 6