Ladder realizations of multivariable positive real functions

Necessary and sufficient conditions are obtained for the realization of an m-variable positive real function (PRF) as the impedence function of a resistively-terminated ladder network of m lossless two-ports connected in cascade. Each two-port is a single-variable lossless ladder with all of its transmission zeros either at the origin or at finity. Conditions are also obtained when each of the two-ports is a Fujisawa-type lowpass ladder.     

Self-regulation of timeout duration in the modification of disruptive classroom behavior

The effects of self-determination vs. teacher-determination of timeout duration on disruptive behavior were investigated in a group of 15 students in a special classroom who had learning disabilities and/or behavior problems. There were five phases to the study: In a repeated measures design each subject received timeout for 5 minutes, no timeout, 5 minutes timeout, selfdetermined timeout duration, and student = teacher-determined timeout duration. The overall effect of timeout was to reduce significantly the rate of disruptive behavior. The effects of various timeout conditions did not differ, indicating self-management of timeout duration was just as effective as when the teacher set the timeout duration.