Showing papers by "Grzegorz Rozenberg published in 1991"

High-level Petri Nets : Theory and Application

Abstract: The paper deals with conceptual, mathematical and practical aspects of developing a net theoretic system model. The model presented is based on common techniques of modelling static systems as structured sets of individuals (relational structures). These structures are 'dynamised' by allowing some relations between individuals to be changed by the processes of the modelled system.

Advances in Petri Nets, 1990

Abstract: A survey of behaviour and equivalence preserving refinements of petri nets.- A distributed simulator for high order Petri nets.- Petri nets with uncertain markings.- Convex geometry and semiflows in P/T nets. A comparative study of algorithms for computation of minimal p-semiflows.- Improving the linearly based characterization of P/T nets.- Linear invariants in commutative high level nets.- Vicinity respecting net morphisms.- Regular stochastic petri nets.- Circuits, handles, bridges and nets.- On the analysis and synthesis of free choice systems.- Petri net models of a distributed election protocol on a unidirectional ring.- Hierarchies in coloured petri nets.- Coloured petri nets: A high level language for system design and analysis.- A simulation system architecture for graph models.- A state transformation preorder over a class of EN systems.- Composition of nets via a communication medium.- ?Trellis: A system for writing and browsing petri-net-based hypertext.- Stubborn sets for reduced state space generation.

Graph Grammars and Their Application to Computer Science: 4th International Workshop Bremen, Germany, March 5-9, 1990 : Proceedings

Abstract: A note on hyperedge replacement.- Graph grammars based on node rewriting: an introduction to NLC graph grammars.- Tutorial introduction to the algebraic approach of graph grammars based on double and single pushouts.- The logical expression of graph properties.- Panel discussion: The use of graph grammars in applications.- GraphEd: An interactive tool for developing graph grammars.- Presentation of the IPSEN-Environment: An Integrated and Incremental Project Support ENviroment.- Presentation of the PROGRESS-Editor: A text-oriented hybrid editor for PROgrammed Graph REwriting SyStems.- PLEXUS: Tools for analyzing graph grammars.- An algebraic theory of graph reduction.- Programming with very large graphs.- Describing Gottler's operational graph grammars with pushouts.- General solution to a system of recursive equations on hypergraphs.- Construction of map OL-systems for developmental sequences of plant cell layers.- Layout graph grammars: The placement approach.- Cycle chain code picture languages.- An efficient implementation of graph grammars based on the RETE matching algorithm.- An application of graph grammars to the elimination of redundancy from functions defined by schemes.- Graphic equivalence and computer optimization.- Graph grammars and logic programming.- Graphs as relational structures : An algebraic and logical approach.- Context-free handle-rewriting hypergraph grammars.- From graph grammars to high level replacement systems.- Algebraic specification grammars: A junction between module specifications and graph grammars.- A characterization of context-free NCE graph languages by monadic second-order logic on trees.- The term generating power of context-free hypergraph grammars.- Elementary actions on an extended entity-relationship database.- Physically-based graphical interpretation of marker cellwork L-systems.- Dactl: An experimental graph rewriting language.- Use graph grammars to design CAD-systems !.- Collage grammars.- The four musicians: analogies and expert systems - a graphic approach.- Structured transformations and computation graphs for actor grammars.- Grammatical inference based on hyperedge replacement.- Specifying concurrent languages and systems with ?-grammars.- Graph rewriting in some categories of partial morphisms.- Application of graph grammars to rule-based systems.- Tree automata, tree decomposition and hyperedge replacement.- Recognizing rooted context-free flowgraph languages in polynomial time.- Computing with graph relabelling systems with priorities.- Double-wall cellwork systems for plant meristems.- Programmed derivations of relational structures.- A specification environment for graph grammars.- The theory of graphoids: A survey.- Graph-reducible term rewriting systems.- A note on graph decimation.- Progress: A VHL-language based on graph grammars.- Movement of objects in configuration spaces modelled by graph grammars.- Recognizing edge replacement graph languages in cubic time.- Computing by graph transformation: Overall aims and new results.

Advances in Petri Nets 1991

Abstract: Delays in synchronized elementary net systems.- Proving temporal properties of Petri nets.- The complexity of testing the equivalence of transition sequences.- Use of reentrant nets in modular analysis of colored nets.- On abstractions of nets.- Semantics, composition and net properties of algebraic high-level nets.- Top-down synthesis of live and bounded free choice nets.- Hood nets.- Distributable nets.- Computer supported design of kanban controlled production.- Optimal simulations, nets and reachability graphs.- An integrated software development methodology based on hierarchical colored Petri nets.- On net systems generated by process foldings.- On liveness preservation by composition of nets via a set of places.- Software implementation of petri nets and compilation of rule-based systems.- Bibliography of Petri nets 1990.

Transition Systems, Event Structures and Unfoldings

Abstract: Elementary transition systems were introduced by the authors in DAIMI PB-310. They were proved to be, in a strong categorical sense, the transition system version of elementray net systems. The question arises whether the notion of a region and the axioms (mostly based on regions) imposed on ordinary transition systems to obtain elementray net systems. Stated differently, one colud ask whether elementray transition systems could also play a role in characterizing other models of concurrency. We show here that by smoothly stengthening the axioms of elementary transition systems one obtains a subclass called occurrence transitions systems which turn out to be categorically equivalent to the well-known model of concurrency called prime event structures. Next we show that occurrence transition systems are to elementry transition systems what occurrence nets are to elementary nets systems. We define an ''unfold'' operation on elementry transition systems which yields occurrence transistion systems. We then prove that this operation uniquely extends to a functor which is the right adjoint to the inclusion functor from (the full subcategory of) occurrence transition systems to (the category of) elementary transition systems. Thus the results of this paper also show that the semantic theory of elementray net systems has a nice counterpart in the more abstract world of transition systems.

Elementary Transition Systems and Refinement

Abstract: The model of Elementary Transition Systems has been introduced by the authors as an abstraction of Elementary Net Systems - with a formal embedding in terms of a categorical coreflection, keeping behavioural information like causality, concurrency and conflict, but forgetting the concrete programming of a particular behaviour over an event set using conditions. In this paper we give one example of the advantages of ETS over ENS, - the definition of local state refinement. We show that the well known problems in understanding within nets the simple notion of syntactic substitution of conditions by (sub) nets behaviourally, - these problems seem to disappear when moving to the more abstract level of ETS. Formally, we show that the ETS-version of condition-substitution does satisfy nice and natural properties, e.g., projection and compositionality results w.r.t. a standard notion of transition system morphisms.

Foundations of Object-Oriented Languages: Rex School Workshop, Noordwijkerhout, the Netherlands, May 28-June 1, 1990 Proceedings

Abstract: The structure and semantics of actor languages.- Designing an object-oriented programming language with behavioural subtyping.- A layered semantics for a parallel object-oriented language.- A proof system for the language POOL.- Object-oriented programming versus abstract data types.- Object-oriented specification in LOTOS and Z, or my cat really is object-oriented!.- A categorial theory of objects as observed processes.- Net-based description of parallel object-based systems, or POTs and POPs.- Describing, structuring and implementing objects.- Modelling features of object-oriented languages in second order functional languages with subtypes.- Graph grammar-based description of object-based systems.- An actor-based metalevel architecture for group-wide reflection.- Producing abstract models for object-oriented languages.

Panel discussion: The use of graph grammars in applications

Abstract: Map L-systems for theoretical cell division patterns provide clues for division patterns in real organisms, which are very often difficult to observe in great detail. From the map L-systems the combinatory of the cell division patterns can be investigated, and wall and cell growth functions can be determined (De Boer and Lindenmayer, 1987). The scope of the patterns that can be generated by map L-systems of a particular size and the architecture of the generated structures (archetypes) have been investigated exhaustively (LUck and LUck, 1986).

Labeled 2-Structures

Abstract: This tutorial presents some basic notions and results of the theory of (labeled) 2-structures.