This paper addresses the problem of designing stabilizing controllers that minimize the 7 l ~ norm of a certain closed-loop transfer function while maintaining the C1 norm of a different transfer function below a prespecified level. This problem arises in the context of rejecting both stochastic as well as bounded persistent disturbances. Alternatively, in a robust control framework it can be t...

An investigation has been carried out to obtain the flow and heat transfer of two dimensional electrically conducting second grade fluids over stretching surface in the presence of uniform magnetic field. The viscosity is assumed to vary as inverse linear function of temperature. The non-linear boundary layer equations together with the boundary conditions are reduced to a system of non-linear ...

Mixed objective control problems have attracted much attention lately since they allow for capturing different performance specifications without resorting to approximations or the use of weighting functions, thus eliminating the need for trial and error type iterations. This paper addresses the problem of designing stabilizing controllers that minimize the 11 norm of a certain closed-loop tran...

in this paper, construction rules of the root locus of a positive feedback system whose loop transfer function is not strictly proper have been investigated. the root locus method is being used since 1950. it is demonstrated that some of the steps in this technique are not general and for a positive feedback system whose loop transfer function is not strictly proper are not valid. to overcome t...

due to the changes which may occur in their parameters, systems are usually demonstrated by some subsystems for different conditions. this paper employs modified petri nets (mpn) to model theses subsystems and makes it simple to analyze them. in this method, first, the continuous transfer function is converted to a discrete transfer function and then, by mpn, system is modeled and analyzed. all...

The paper considers the so-called dynamic phasor model as a basis for harmonic analysis of a class of switching systems. The dynamic phasor model is a powerful tool for exploring cyclic properties of dynamic systems. It is shown that there is a connection between the dynamic phasor model and the harmonic transfer function of a linear time periodic system and this connection is used to extend th...

In control and circuit theory it is important to test if the given transfer function is positive real. In this paper an efficient computational procedure for testing if a given transfer function in discrete-time is positive real is presented. The algorithm is based on the continuous-time case and uses only standard matrix computations. The input for these tests is the state-space representation...

This note first characterizes the class of all stabilizing controllers for a two-degree-of-freedom control system which achieve a prescribed achievable transfer function. The characterization is in terms of an arbitrary proper stable transfer function. With this characterization, robust model matching is formulated as a standard Hm-optimization problem. This means that standard controller desig...

We present a method for measuring the complete linear response, including amplitude, phase, and polarization, of a fiber-optic component or assembly that requires only a single scan of a tunable laser source. The method employs polarization-diverse swept-wavelength interferometry to measure the matrix transfer function of a device under test. We outline the theory of operation to establish how ...

We show how to optimize the shape of the transfer function of a linear time invariant (LTI) single-input-single-output (SISO) system. Since any transfer function is rational, this can be formulated as an optimization problem for the coefficients of polynomials. After characterizing the cone of polynomials which are nonnegative on intervals, we formulate this problem using semidefinite programmi...