a nonstandard finite difference (nsfd) scheme has been constructed and analyzed for a mathematical model that describes lotka–volterra food web model. this new discrete system has the same stability properties as the continuous model and,on the whole, it preservesthe same local asymptotic stability properties. linearized stability theory and schur–cohn criteria are used for local asymptoticstab...

In the second-half of the last century, the development of systems and control theory, together with the achievements of digital control and signal processing, has set the stage for renewed interest in the study of periodic systems, both in continuous and discrete time; see, e.g., [24, 45, 36, 10, 43, 12] and the survey papers [3, 4]. This has been amplified by specific application demands in t...

Descriptor systems constitute an important class of systems of both theoretical and practical interests and have been attracting the attention of many researchers over recent decades. This dissertation is concerned with non-standard H2 and H∞ control for linear time-invariant descriptor systems. Within the descriptor framework, the contributions of this dissertation are threefold: i) review of ...

In this report a derivation of the MAP state estimator objective function for general (possibly nonsquare) discrete time causal/non-causal descriptor systems is presented. The derivation made use of the Kronecker Canonical Transformation to extract the prior distribution on the descriptor state vector so that Maximum a Posteriori (MAP) point estimation can be used. The analysis indicates that t...

In this paper we give a survey on balanced truncation model order reduction for linear time-invariant continuous-time systems in descriptor form. We first give a brief overview of the basic concepts from linear system theory and then present balanced truncation model reduction methods for descriptor systems and discuss their algorithmic aspects. The efficiency of these methods is demonstrated b...

This dissertation deals with the problem of enabling precise and real-time retrieval of generic 3D models. We focus on three subproblems, namely, rotation normalization, discriminative shape representations and relevance feedback-based retrieval. Considering the first problem, we develop a rotation normalization method that computes the object’s principal axes using the orientation of the objec...

The paper is concerned with robust H∞ non-fragile controller design for uncertain descriptor systems with time-delay. A descriptor system has potential to describe a wide class of physical systems. It can give a representation of the system with algebraic constraints. A unique characteristic of descriptor systems is possible impulse modes and nonregularity, which do not appear in state-space sy...

A dynamical system is called positive if its trajectory starting from any nonnegative initial state remains forever in the positive orthant for all nonnegative inputs. An overview of state of the art in positive theory is given in the monographs [1, 2]. Variety of models having positive behavior can be found in engineering, economics, social sciences, biology and medicine, etc.. Positive linear...