The front page of this Newsletter contained a message from Anthony G. Zimbalatti - Membership Chairman the G-27 Group.

In this paper, we present a geometric method for describing the effects of the delay induced uncertainty on the stability of a standard Smith Predictor control scheme. The method consists of deriving the stability crossing curves in the parameter space defined by the nominal delay, and delay uncertainty, respectively. More precisely, we start by computing the crossing set, which consists of all...

Smith was a pioneer epidemiologist, bacteriologist, and pathologist who made many contributions to medical science that were of far-reaching importance. He is best known for his work on Texas cattle fever, in which he and his colleagues discovered the protozoan agent and its means of transmission by ticks. This was the ¿ rst time that an arthropod had been de¿ nitively linked with the transmiss...