Transfer function determination from impulse response via walsh functions

This paper presents a new method for calculating a rational transfer function matrix using a Walsh expansion of the impulse response matrix. The algorithm proposed appears to be computationally convenient owing to certain properties of the Walsh functions. An example is given to illustrate the method.     

Mixed time/frequency domain approach to model reduction

The letter considers the problem of reducing the transfer function of a given system to a lower order. The approach proposed appears to be suitable in cases where both the frequency-domain and the time-domain characteristics of the given system are to be preserved in the reduced order model.     

Constrained Learning in Neural Networks: Application to Stable Factorization of 2-D Polynomials

Adaptive artificial neural network techniques are introduced and applied to the factorization of 2-D second order polynomials. The proposed neural network is trained using a constrained learning algorithm that achieves minimization of the usual mean square error criterion along with simultaneous satisfaction of multiple equality and inequality constraints between the polynomial coefficients. Using this method, we are able to obtain good approximate solutions for non-factorable polynomials. By incorporating stability constraints into the formalism, our method can be successfully used for the realization of stable 2-D second order IIR filters in cascade form.     

Untersuchungen an drei stählernen Speerspitzen aus dem 7. und 6. Jahrhundert v. Chr.

Ergebnisse metallkundlicher Untersuchungen an drei stählernen Speerspitzen aus Mykenä (Griechenland). Sie dienten vermutlich als Opfergaben für den Mars-Tempel, an dessen Auβenmauern sie zusammen mit Keramikvasen gefunden wurden, die eine Datierung in das 7. bis 6. Jh. v. Chr. gestatten. Infolge Fehlens entsprechender Rohstoffe in Griechenland dürfte es sich um aus Kleinasien eingeführte Waffen oder um einen Fall der Verarbeitung von aus dem Nahen Osten eingeführtem Halbzeug handeln.     

Model reduction of 2-D systems via orthogonal series

In this article, the problem of model reduction of 2-D systems is studied via orthogonal series. The algorithm proposed reduces the problem to an overdetermined linear algebraic system of equations, which may readily be solved to yield the simplified model. When this model approximates adequately the original system, it has many important advantages, e.g., it simplifies the analysis and simulation of the original system, it reduces the computational effort in design procedures, it reduces the hardware complexity of the system, etc. Several examples are included which illustrate the efficiency of the proposed method and gives some comparison with other model reduction techniques.