Branching processes of Petri nets

Summary The notion of a branching process is introduced, as a formalization of an initial part of a run of a Petri net, including nondeterministic choices. This generalizes the notion of a process in a natural way. It is shown that the set of branching processes of a Petri net is a complete lattice, with respect to the natural notion of partial order. The largest element of this lattice is the unfolding of the Petri net.     

Least Squares and Robust Estimation of Local Image Structure

Linear scale space methodology uses Gaussian probes at scale s to observe the differential structure. In observing the differential image structure through the Gaussian derivative probes at scale s we implicitly construct the Taylor series expansion of the smoothed image. The Gaussian facet model, as a generalization of the classic Haralick facet model, constructs a polynomial approximation of the unsmoothed image. The measured differential structure therefore is closer to the ‘real’ structure than the differential structure measured using Gaussian derivatives.At the points in an image where the differential structure changes abruptly (because of discontinuities in the imaging conditions, e.g. a material change, or a depth discontinuity) both the Gaussian derivatives and the Gaussian facet model diffuse the information from both sides of the discontinuity (smoothing across the edge).Robust estimators that are classically meant to deal with statistical outliers can also be used to deal with these ‘mixed model distributions’. In this paper we introduce the robust estimators of local image structure. Starting with the Gaussian facet model where we replace the quadratic error norm with a robust (Gaussian) error norm leads to a robust Gaussian facet model.We will show examples of using the robust differential structure estimators for luminance and color images, for zero and higher order differential structure. Furthermore we look at a ‘robustified’ structure tensor that forms the basis of robust orientation estimation.First online version published in June, 2005     

Voice communication with computers: A primer

Due to the rapid development of speech communication interfaces, speech will be a major mode of man-machine communication. Essential to the development of speech input/output applications is the understanding of the techniques and jargon of speech by the application designer who, in most cases, has no formal speech training and, perhaps, little understanding of computers. This paper includes introductory tutorials on speech synthesis and recognition in an attempt to overcome the jargon barrier. A limited number of application examples are presented to stimulate generation of new applications.     

Automated enzymatic determination of starch in meat products

Summary An automated method is described for the enzymatic determination of starch in some meat products. After solubilization with dimethylsulfoxide/hydrochloric acid, the starch was automatically determined with amyloglucosidase (EC 3.2.1.3) and hexokinase (EC 2.7.1.1)/glucose-6-phosphate dehydrogenase (EC 1.1.1.49) using a Technicon AutoAnalyzer II System. The analyses could be performed at a rate of forty samples per hour. The results agree very well with those obtained by the polarimetric method.

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Eine automatisierte enzymatische Bestimmung der Stärke in Fleischerzeugnissen

Zusammenfassung Eine automatische Methode zur enzymatischen Bestimmung der Stärke in Fleischerzeugnissen wird beschrieben. Nach Lösung in einer Dimethylsulfoxide/Salzsäure-Mischung, wurde Stärke mittels Amyloglucosidase (EC 3.2.1.3) and Hexokinase (EC 2.7.1.1)/Glukose-6-phosphatdehydrogenase (EC 1.1.1.49) mit Hilfe des Technicon AutoAnalyzers II automatisch bestimmt. Diese Methode ermöglicht 40 Proben pro Std. zu untersuchen. Die Ergebnisse stimmen gut mit den Analysenwerten der polarimetrischen Bestimmung überein.

     

Surface tree languages and parallel derivation trees

The surface tree languages obtained by top-down finite state transformation of monadic trees are exactly the frontier-preserving homomorphic images of sets of derivation trees of ETOL systems. The corresponding class of tree transformation languages is therefore equal to the class of ETOL languages.     

Three hierarchies of transducers

Composition of top-down tree transducers yields a proper hierarchy of transductions and of output languages. The same is true for ETOL systems (viewed as transducers) and for two-way generalized sequential machines.     

Apex graph grammars and attribute grammars

Summary Apex graph grammars are a particular type of directed node-label controlled (DNLC) graph grammars: the embedding edges are established between terminal nodes only. Apex graph grammars, slightly generalized, can generate the sets of dependency graphs of attribute grammars. The other way around, every apex graph language can be obtained from such a dependency graph language by a graph replacement (which is an operation analogous to a string homomorphism).     

Iterated deterministic substitution

Summary Deterministic substitution of languages means substituting the same word (from a given language) for all occurrences of a symbol. For an arbitrary family K of languages the notion of deterministic K-iteration grammar is introduced, which is essentially the iteration of a finite number of deterministic substitutions of languages from K. The families of languages generated by these grammars are investigated.The work of the first author has been supported by the Netherlands Organization for the Advancement of Pure Research (Z.W.O.)