Grenzen der Anwendbarkeit der Theorie der analytischen Signale

Zusammenfassung Bei der praktischen Anwendung der analytischen Signale ist es erforderlich, die Ermittlung der Hilbert-Transformation numerisch durchzuführen. Dazu wurden u.a. Verfahren von H.W. Schü?ler, R. Unbehauen und G. Wunsch vorgeschlagen. In der Arbeit werden allgemeine Ergebnisse zur numerischen Umsetzung der Hilbert-Transformation dargestellt. Es wird gezeigt, da? alle praktisch realisierbaren Verfahren für bestimmte Signale divergieren. Damit ist es m?glich, die in der Experimentalphysik schon l?nger bekannten Schwierigkeiten bei der Umsetzung der Hilbert-Transformation zu erkl?ren.     

Overview of ship-design expert systems

Expert systems constitute a branch of artificial intelligence, and their unique characteristics enable computer systems to perform at the level of a human expert by the use of algorithms that can capture domain-specific knowledge. Through an extensive survey of research about ship-design expert systems, we conclude that although development and implementation of expert systems for ship design offer substantial barriers, the shipbuilding industry needs them nonetheless. We examine the major reasons that use of expert systems in this industry has lagged behind. These include the problems of integration with existing computer-aided design systems, problems of knowledge representation and sizable development costs. We discuss in detail some key factors that can lead to the solution of these problems.     

The effects of pressure on the isothermal fluid behavior of bituminous coals

An investigation into the effects of pressure (helium gas) on the isothermal fluid behavior includes: (1) the effect of pressure on the rate of melting and coking as evidenced by the rate constants k(melt) and k(coke); (2) the effect of pressure on the energies of activation of melting and coking; (3) the effects of pressure on the characteristic times; (4) the effects of pressure on the maximum isothermal fluidity. Results from the effects of pressure on k(melt) revealed that it was generally the high total sulfur, low nitrogen, low reactives/mineral matter ratio, medium rank coals which show the greatest increase in k(melt), whereas the highest rank coals show the least decrease in k(coke). The energies of activation of melting and coking were not significantly affected by pressure. The investigation also reveals increases or decreases in the respective times of softening, maximum fluidity, resolidification and total time of fluid behavior under isothermal pressurized conditions. There appears the possibility that these shifts may be rank dependent. Additionally, the lower rank coals show the largest relative increase in their fluidities when subjected to pressure. Empirical relationships were derived in order to quantitatively predict the maximum isothermal fluidity for most (fluid) coals at a given pressure.     

Computing hysteresis points of nonlinear equations depending on two parameters

A direct method is described for computing a hysteresis point (double turning point) corresponding to a cusp point of a system ofn nonlinear equations inn variables depending on two parameters. By addition of two equations a minimally extended system ofn+2 nonlinear equations is constructed for which the hysteresis point is an isolated solution. An efficient implementation of Newton's method is presented not requiring evaluations of second derivatives of the original problem. Two numerical examples show the efficiency of theQ-quadratically convergent method.     

Betriebsvereinbarung contra BDSG?

Ob Betriebsvereinbarungen im Sinne des § 4 Abs. 1 BDSG eine „andere Rechtsvorschrift” sind und damit die Regelungen des BDSG einschr?nken dürfen, geh?rt zu den Standardfragen des praktischen Arbeitnehmerdatenschutzes. Die Autoren befürworten eine weite betriebliche Regelungskompetenz, beschr?nken diese aber zum Schutz der Arbeitnehmer durch eine Reihe datenschutzrechtlicher Mindestanforderungen, die Betriebsvereinbarungen einzuhalten haben.     

A note on surface waves in anisotropic media

Summary An examination of possible forms of traction free surface wave in anisotropic elastic materials is undertaken. The results yield some interesting features of a certain arbitrariness which exists in displacement waves on a traction free surface in anisotropic media.