Applying Algebraic Approaches for Modeling Workflows and their Transformations in Mobile Networks

In emergency scenarios we can obtain a more effective coordination among team members, each of them equipped with hand-held devices, through the use of workflow management software. Team members constitute a Mobile Ad-hoc NETwork (MANET), whose topology both influences and is influenced by the workflow. In this paper we propose an algebraic approach for modeling workflow progress as well as its modifications as required by topology transformations. The approach is based on Algebraic Higher-Order Nets and sees both workflows and topologies as tokens, allowing their concurrent modification

Modelling Evolution of Communication Platforms and Scenarios based on Transformations of High-Level Nets and Processes : Extended Version

Algebraic High-Level (AHL) nets are a well-known modelling technique based on Petri nets with algebraic data types, which allows to model the communication structure and the data flow within one modelling framework. Transformations of AHL-nets – inspired by the theory of graph transformations – allow in addition to modify the communication structure. Moreover, high-level processes of AHL-nets capture the concurrent semantics of AHL-nets in an adequate way. Altogether we obtain a powerful integrated formal specification technique to model and analyse all kinds of communication based systems, especially different kinds of communication platforms. In this paper we show how to model the evolution of communication platforms and scenarios based on transformations of Algebraic High-Level Nets and Processes. All constructions and results are illustrated by a running example showing the evolution of Apache Wave platforms and scenarios. The evolution of platforms is modelled by the transformation of AHL-nets and that of scenarios by the transformation of AHL-net processes. The first main result shows under which conditions AHL-net processes can be extended if the corresponding AHL-net is transformed. This result can be applied to show the extension of scenarios for a given platform evolution. The second main result shows how AHL-net processes can be transformed based on a special kind of transformation for AHL-nets, corresponding to action evolution of platforms. Finally, we briefly discuss the case of multiple action evolutions

An Algebraic Approach to Timed Petri Nets with Applications to Communication Networks

In this report, we define a formalism for a time-extension to algebraic place/transition (P/T) nets. This allows time durations to be assigned to the transitions of a P/T net, representing delays present in the systems that are being modelled, which in turn influence (restrict) the firing behaviour of the nets. This is especially useful when modelling time-dependent systems. The new contribution of this approach is the definition of categories for the timed net classes of timed P/T nets, timed P/T systems and timed P/T states. Moreover, we define functorial relations between these categories as well as functorial relations to categories of untimed P/T nets and systems. The first main result is the formalisation of morphisms for all three net classes that preserve firing behaviour. The second main result is the equivalence of the categories of timed P/T systems and states, establishing a relation between structurally identical nets with a time offset. As a third main result we formalise structuring techniques for timed P/T nets and show that timed P/T nets fit in the framework of M-adhesive categories

Modellierung und Simulation von IT-Dienstleistungsprozessen

Eine der Ursachen für die ungenaue Bestimmung von Service-Levels in IT-Dienstleistungsvereinbarungen liegt in der informellen Repräsentation von IT-Dienstleistungsprozessen. In der Arbeit wird eine integrierte Methode entwickelt, mit der Dienstanbieter verschiedene Qualitätsmerkmale von IT-Dienstleistungen und die zu ihrer Erbringung benötigten IT-Dienstleistungsprozesse modellieren und simulieren können

Modellierung und Simulation von IT-Dienstleistungsprozessen

Eine der Ursachen für die ungenaue Bestimmung von Service-Levels in IT-Dienstleistungsvereinbarungen liegt in der informellen Repräsentation von IT-Dienstleistungsprozessen. In der Arbeit wird eine integrierte Methode entwickelt, mit der Dienstanbieter verschiedene Qualitätsmerkmale von IT-Dienstleistungen und die zu ihrer Erbringung benötigten IT-Dienstleistungsprozesse modellieren und simulieren können

High-Level Net Processes

The notion of processes for low-level Petri nets based on occurrence nets is well known and it represents the basis for the study of the non-sequential behavior of Petri nets. Processes for high-level nets N are often defined as processes of the low level net Flat(N) which is obtained from N via a construction called "flattening". In this paper we define high-level processes for high-level nets based on a suitable notion of high-level occurrence nets. The flattening of a high-level occurrence net is in general not a low-level occurrence net, due to so called "assignment conflicts" in the high-level net. The main technical result is a syntactical characterization of assignment conflicts. But the main focus of this paper is a conceptual discussion of future perspectives of high-level net processes including concurrency and data type aspects. Specifically, in the second part of the paper, we discuss possible extensions of high-level net processes, which are formally introduced for algebraic high-level nets in the first part of this paper. Of special interest are high-level processes with data type behavior, amalgamation, and other kinds of constructions, which are essential aspects for a proposed component concept for high-level nets

High-Level Net Processes

Abstract. The notion of processes for low-level Petri nets based on oc-currence nets is well known and it represents the basis for the study of the non-sequential behavior of Petri nets. Processes for high-level nets N are often defined as processes of the low level net F lat(N) which is obtained from N via a construction called ”flattening”. In this paper we define high-level processes for high-level nets based on a suitable notion of high-level occurrence nets. The flattening of a high-level occurrence net is in general not a low-level occurrence net, due to so called ”assignment conflicts ” in the high-level net. The main technical result is a syntacti-cal characterization of assignment conflicts. But the main focus of this paper is a conceptual discussion of future perspectives of high-level net processes including concurrency and data type aspects. Specifically, in the second part of the paper, we discuss possible extensions of high-level net processes, which are formally introduced for algebraic high-level nets in the first part of this paper. Of special interest are high-level processes with data type behavior, amalgamation, and other kinds of construc-tions, which are essential aspects for a proposed component concept for high-level nets.