A standard result of linear-system theory states that a SISO rational th-order transfer function always has an th-order realization. In some applications, one is interested in having a realization with nonnegative entries (i.e., a positive system) and it is known that a positive system may not be minimal in the usual sense. In this paper, we give an explicit necessary and sufficient condition f...

This paper proposes general eigenvalue-based passivity tests for descriptor state space systems, extending the already available tests for standard state space systems. Generalized eigenvalue tests are proposed to identify passivity violations in the positive-real and bounded-real cases. The important practical case of singular descriptor state space systems is also treated. The proposed passiv...

Background: Malaria is still account for 200 million cases annually. Microscopy is the gold standard technique for malaria parasites detection. PCR-based techniques can detect malaria infections with high sensitivity. The study aimed to evaluate the sensitivity of microscopy technique in the detection of P. falciparum and P. vivax, using monoplex real-time PCR, Gezira State, Central Sudan. Met...

The symmetric moment problem is to find a possibly unique, positive symmetric measure that will produce a given sequence of moments {Mn}. Let us assume that the (Hankel) condition for existence of a solution is satisfied, and let σn be the unique measure, supported on n points, whose first 2n moments agree with M0, . . . ,M2n−1. It is known that σ2n =⇒ σ0 (weak convergence) and σ2n+1 =⇒ σ∞, whe...

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...