Because the number of state variables in a reduced-order observer is less than the order n of S by the number m of (independent) observations, the reduced-order observer is parsimonious, often a desirable engineering quality. But, in addition, a reduced-order observer may have better properties than a full-order observer, especially with regard to robustness of a control system which uses an ob...

For dynamics ẋ = f(x) with output y = h(x) invariant with respect to a transformation group G, we define invariant asymptotic observer of the form ̇̂ x = f̂(x̂, y) where y = h(x) is the measured output and x̂ an estimation of the unmeasured state x. Such a definition is motivated by a class of chemical reactors, treated in details, when the group of transformations corresponds to unit changes and t...

We analyze experimental evidence on whether untrained subjects can predict how trustworthy an individual is. Two players on a TV show play a high stakes prisoner’s dilemma with pre-play communication. Our subjects report probabilistic beliefs that each player cooperates, before and after communication. Subjects correctly predict that women, and players who voluntarily promise that they will coo...

State estimation in nonlinear systems is important in applications like monitoring, fault diagnosis and nonlinear control. However, for large-scale systems, or naturally distributed applications, the construction and tuning of a centralized observer may present difficulties. Therefore, we propose the decomposition of the model into simpler subsystems. A large class of nonlinear systems can be w...