In this paper we consider a pseudo-formal linearization that transforms a given nonlinear system into a pseudolinear system. The given nonlinear system is linearized piecewise by the formal linearization method based on a Taylor expansion considering up to higher-order terms, and then each piecewise linearized system is smoothly united into a single linearized system by an automatic choosing function. The error bounds of this pseudo-formal linearization indicate that the accuracy of the approximation is improved when the domain is reasonably divided and as the order of the polynomials increases. A nonlinear observer and a nonlinear filter are also synthesized as applications of the pseudo-formal linearization. The high validity of this method is verified through numerical examples.
In Session 10, we showed that the telegrapher's equations can be extended using the Riccati differential equation and that a new circuit element can be obtained. In Session 11, we showed that the Dirac equation, which is used in quantum theory, can be expressed as the extended telegrapher's equations and that circuit theory can be applied to the Dirac equation. In this session, we demonstrate that a new circuit element can be obtained by applying reactive power to the Dirac equation. In this case, energy given by Einstein's well-known formula E = mc2 should be considered for the discussion on an ordinary world that does not require the theory of relativity.