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Presents the President?s Message for this issue of the publication. [ABSTRACT FROM PUBLISHER]

The article discusses the relevance of control in the field of engineering. Topics discussed include the less acknowledge contributions of engineering to developments in modern technology, the need for professionals working in automatic control to educate the public about the nature and importance of their work and the promise seen with initiatives like the two "Impact of Control Technology."

Presents the President?s Message for this issue of the publication. [ABSTRACT FROM PUBLISHER]

Recently a model for the interplay between homophily-based appraisal dynamics and influence-based opinion dynamics has been proposed. The model explores for the first time how the opinions of a group of agents on a certain number of issues/topics is influenced by the agents’ mutual appraisal and, conversely, the agents’ mutual appraisal is updated based on the agents’ opinions on the various issues, according to a homophily model. In this paper we show that a simplified (and, in some situations, more feasible) version of the model, that accounts only for the signs of the agents’ appraisals rather than for their numerical values, provides an equally accurate and effective model of the opinion dynamics in small networks. The equilibria reached by this model correspond, almost surely, to situations in which the agents’ network is complete and structurally balanced. On the other hand, we ensure that such equlibria can always be reached in a finite number of steps, and, differently from the original model, we rule out other types of equilibria that correspond to disconnected social networks.

In this paper, exponential stabilizability of continuous-time positive switched systems is investigated. For two-dimensional systems, exponential stabilizability by means of a switching control law can be achieved if and only if there exists a Hurwitz convex combination of the (Metzler) system matrices. In the higher dimensional case, it is shown by means of an example that the existence of a Hurwitz convex combination is only sufficient for exponential stabilizability, and that such a combination can be found if and only if there exists a smooth, positively homogeneous and co-positive control Lyapunov function for the system. In the general case, exponential stabilizability ensures the existence of a concave, positively homogeneous and co-positive control Lyapunov function, but this is not always smooth. The results obtained in the first part of the paper are exploited to characterize exponential stabilizability of positive switched systems with delays, and to provide a description of all the “switched equilibrium points” of an affine positive switched system. [ABSTRACT FROM AUTHOR]

In this paper we consider the class of discrete-time switched systems switching between p autonomous positive subsystems. First, sufficient conditions for testing stability, based on the existence of special classes of common Lyapunov functions, are investigated, and these conditions are mutually related, thus proving that if a linear copositive common Lyapunov function can be found, then a quadratic positive definite common function can be found, too, and this latter, in turn, ensures the existence of a quadratic copositive common function. Secondly, stabilizability is introduced and characterized. It is shown that if these systems are stabilizable, they can be stabilized by means of a periodic switching sequence, which asymptotically drives to zero every positive initial state. Conditions for the existence of state-dependent stabilizing switching laws, based on the values of a copositive (linear/quadratic) Lyapunov function, are investigated and mutually related, too. [ABSTRACT FROM PUBLISHER]

In this technical note, reachability properties of continuous-time positive systems are introduced and characterized. Specifically, first it is shown that reachability and strong reachability are equivalent properties, and thus the characterization of strong reachability derived in is extended to the weaker notion of reachability. In the second part of the technical note, essential reachability is introduced, and necessary and sufficient conditions for this property to hold are provided. [ABSTRACT FROM AUTHOR]

A table that shows the 949 long-term members of the Control Systems Society (CSS) is presented, including the years of their membership to the Society.

The observer design problem is investigated in the context of linear left shift invariant discrete behaviors, whose trajectories have supports on Z+. Necessary and sufficient conditions for the existence of a dead-beat observer of some relevant variables from some measured ones, in the presence of some unmeasured (and irrelevant) variables, are introduced, and a complete parametrization of all dead-beat observers is given. Equivalent conditions for the existence of causal dead-beat observers are then derived. Finally, several classical problems addressed for state-space models, like state estimation, the design of unknown input observers or the design of fault detectors and identifiers (possibly in the presence of disturbances), are cast in this general framework, and the aforementioned equivalent conditions and parametrizations are specialized to these cases. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the following problem is addressed: given a two-dimensional complete behavior and one of its sub-behaviors , under what conditions a third complete behavior can be found, such that and is finite-dimensional autonomous? This constitutes a complete generalization of the decomposition theorem, as it represents a decomposition with “minimal intersection”, in which one of the two terms has been a priori fixed. The analysis carried on here completes the preliminary results reported in [Bisiacco and Valcher, Multidimensional Systems and Signal Processing, vol. 13,2002, pp. 289–315]. and completely generalizes the direct sum decomposition problem presented in [Bisiacco and Valcher, IEEE Transactions on Circuits and Systems Part I, CAS-I-48, no-4, 2001, pp. 490–494].

The article focuses on the process involved in peer review which is crucial to the acceptance or rejection of a paper. Topics discussed include the stages of peer review such as prepublication review and post-publication review, kinds of peer review such as blind, double blind and open peer review, and the establishment of the Committee on Papers by the Royal Society of London member and Philosophical Transactions of the Royal Society founding editor Henry Oldenburg in 1665.

The article presents a call for volunteers to members of the Institute of Electrical and Electronics Engineers (IEEE) Control Systems Society (CSS), and discusses the contributions of CSS volunteers and benefits of being a volunteer. Topics discussed include review of conference and journal papers to keep volunteers up to date on new ideas and improve expository skills, leadership skills development with CSS committee participation, and Membership Activities Board (MAB).

Analyzes the observer design problem in the behavioral context. Observability and detectability notions; Conditions for the existence of an observer; State-space systems and associated issues; Trajectories satisfying differential equations.

Discusses the stability properties and periodic evolutions of bilinear systems in input-output form. Derivation of the sufficient conditions for bounded-input/bounded output stability; Polar structure of the rational functions describing the input-output maps; Output evolution determined by finite support input sequences.

Focuses on the design of a full-order state observer for a discrete-time linear systems with unknown inputs. Sufficient conditions for the existence of an asymptotic observer; Estimation of the state of a linear system; Restatement of the design in algebraic terms.

LetG(z1,z2) be ap×m 2D proper rational transfer matrix, with full column rank, and ?=(A1,A2,B1,B2,C, D) a state-space realization of its. Necessary and sufficient conditions are presented in this paper, which guarantee that (i)G(z1,z2) admits polynomial left inverses, (ii) such polynomial inverses are transfer matrices of some inverse system of ?. When the above conditions are not fulfilled, the existence of stable and/or proper, possibly delayed, inverses ofG(z1,z2), is also discussed.

Presents the President's message for this issue of the publication. [ABSTRACT FROM PUBLISHER]

Presents the President?s Message for this issue of the publication. [ABSTRACT FROM PUBLISHER]

This article focuses on the call for volunteers by the IEEE Control Systems Society (CSS). The CSS has been successful in its missions with the help of its volunteers. The organization looks for new volunteers each year to participate in its activities. Volunteers may be involved in providing peer reviews for conference and journal papers. Involvement in peer reviews is one way to help improve the quality of the organization's technical literature. A peer reviewer will review papers submitted to the organization's annual conferences.