Towards Translating Graph Transformation Approaches by Model Transformations

Recently, many researchers are working on semantics preserving model transformation. In the field of graph transformation one can think of translating graph grammars written in one approach to a behaviourally equivalent graph grammar in another approach. In this paper we translate graph grammars developed with the GROOVE tool to AGG graph grammars by first investigating the set of core graph transformation concepts supported by both tools. Then, we define what it means for two graph grammars to be behaviourally equivalent, and for the regarded approaches we actually show how to handle different definitions of both - application conditions and graph structures. The translation itself is explained by means of intuitive examples

Formal Modeling of Communication Platforms using Reconfigurable Algebraic High-Level Nets

Communication nowadays is based on communication platforms like Skype, Facebook, or SecondLife. The formal modeling and analysis of communication platforms poses considerable challenges, namely highly dynamic structures and complex behavior. Since most of the well-known formal modeling approaches are adequate only for specific aspects of communication platforms, in this paper we introduce the approach of reconfigurable algebraic high-level nets with individual tokens and show in our case study Skype that this approach is adequate for modeling the main aspects and features of communication platforms

Independence Analysis of Firing and Rule-based Net Transformations in Reconfigurable Object Nets

The main idea behind Reconfigurable Object Nets (RONs) is to support the visual specification of controlled rule-based net transformations of place/transition nets (P/T nets). RONs are high-level nets with two types of tokens: object nets (place/transition nets) and net transformation rules (a dedicated type of graph transformation rules). Firing of high-level transitions may involve firing of object net transitions, transporting object net tokens through the high-level net, and applying net transformation rules to object nets, e.g. to model net reconfigurations. A visual editor and simulator for RONs has been developed as a plug-in for ECLIPSE using the ECLIPSE Modeling Framework (EMF) and Graphical Editor Framework (GEF) plug-ins. The problem in this context is to analyze under which conditions net transformations and token firing can be executed in arbitrary order. This problem has been solved formally in a previous paper. In this contribution we present an extension of our RON tool which implements the analysis of conflicts between parallel enabled transitions, between parallel applicable net transformation rules (Church-Rosser property), and between transition firing and net transformation steps. The conflict analysis is applied to a RON simulating a distributed producer-consumer system

Categorical Foundation for Layer Consistency in AHO-Net Models Supporting Workflow Management in Mobile Ad-Hoc Networks

In this paper we present a layered architecture for modeling workflows in Mobile Ad-Hoc NETworks (MANETs) using algebraic higher order nets (AHO nets). MANETs are networks of mobile devices that communicate with each other via wireless links without relying on an underlying infrastructure, e.g. in emergency scenarios, where an effective coordination is crucial among team members, each of them equipped with hand-held devices. Workflows in MANETs can be adequately modeled using a layered architecture, where the overall workflow, the team members' activities and the mobility issues are separated into three different layers, namely the workflow layer, the mobility layer and the team layer. Dividing the AHO net model into layers immediately rises the question of consistency. We suggest a formal notion of layer consistency requiring that the team layer is given by the mapping of the individual member's activities to the gluing of the workflow and the mobility layer. The main results concern the maintenance of the layer consistency when changing the workflow layer, the mobility layer and the team layer independently

Formalization of Petri Nets with Individual Tokens as Basis for DPO Net Transformations

Reconfigurable place/transition systems are Petri nets with initial markings and a set of rules which allow the modification of the net structure during runtime. They have been successfully used in different areas like mobile ad-hoc networks. In most of these applications the modification of net markings during runtime is an important issue. This requires the analysis of the interaction between firing and rule-based modification. For place/transition systems this analysis has been started explicitly without using the general theory of M-adhesive transformation systems, because firing cannot be expressed by rule-based transformations for P/T systems in this framework. This problem is solved in this paper using the new approach of P/T nets with individual tokens. In our main results we show that on one hand this new approach allows to express firing by transformation via suitable transition rules. On the other hand transformations of P/T nets with individual tokens can be shown to be an instance ofM-adhesive transformation systems, such that several well-known results, like the local Church-Rosser theorem, can be applied. This avoids a separate conflict analysis of token firing and transformations. Moreover, we compare the behavior of P/T nets with individual tokens with that of classical P/T nets. Our new approach is also motivated and demonstrated by a network scenario modeling a distributed communication system

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

Formale Modellierung, Simulation and Validierung von Kommunikationsplattformen

Kommunikationsbasierte Systeme, welche sich nach Menschen und deren Bedürfnissen orientieren, erlangten in den letzten Jahren immer größere Bedeutung und Interesse. Bislang gibt es allerdings keine angemessene umfassende Modellierungstechnik für diese Art von Kommunikationsplattformen, welche es erlauben würden, das Benutzerverhalten in derartigen Systemen formal zu modellieren, zu simulieren und zu validieren. In dieser Dissertation stellen wir eine geeignete Integration von algebraischen high-level Petrinetzen und high-level Ersetzungssystemen vor, um diese Lücke zu schließen. Von der theoretischen Seite her erfordert dies, eine Theorie algebraischer high-level Netze zu entwickeln, so dass einerseits die entsprechenden high-level Ersetzungssysteme den Eigenschaften M-adhesiver Transformationssysteme genügen und andererseits der Entwickler von Kommunikationsplattformen deren Schaltverhalten und regelbasierte Modifikation innerhalb eines Frameworks modellieren und analysieren kann. Von der konzeptuellen Seite her können wir nachweisen, dass typische Eigenschaften von Kommunikationsplattformen innerhalb dieses Frameworks unter Vewendung geeigneter Modellierungstechniken modelliert und validiert werden können, wie etwa Anrufe, Chats zwischen verschiedenen Benutzern, Konferenzen, Datenmulticasting, sowie Plattform-Constraints und andere. Dies demonstrieren wir anhand von Skype, welches uns durch die ganze Arbeit als Leitfaden, Beispiel und umfassende Fallstudie dient. Abschließend beschreiben wir die Entwicklung eines visuellen Werkzeugs für Kommunikations\-platt\-formen in Eclipse, welches den Entwickler beim Modellieren, Simulieren und Validieren unterstützt.Human-centric communication-based systems, including social networks as Skype, Facebook, and Second Life, have been of increasing interest throughout the last years. Up to now, however, there are no adequate modeling techniques for this kind of communication platforms that would allow formal modeling, simulation, and validation of the user behavior. In this thesis, we propose a suitable integration of algebraic high-level Petri nets and high-level replacement systems, based on well-known graph transformation techniques, in order to close this gap. On the theoretical side, this requires to develop a theory of algebraic high-level nets with individual tokens, such that the corresponding high-level replacement systems satisfy the requirements of M-adhesive transformation systems and allow the platform designer to model and to analyze token-firing and rule-based modification within a single framework. On the conceptual side, we are able to show that typical features of communication platforms such as direct calls, multi-user chats, conferences, data multicasting, platform constraints and other requirements can be modeled and validated in this framework combining suitable modeling techniques. This is demonstrated for Skype, which is used as a running example and case study. Last but not least, it is shown how to develop a visual Eclipse-based tool for communication platforms, which supports modeling, simulation, and validation of typical scenarios

ELECTRONIC COMMUNICATIONS OF THE EASST Towards Translating Graph Transformation Approaches by Model Transformations

Abstract. Recently, many researchers are working on semantics preserving model transformation. In the field of graph transformation one can think of translating graph grammars written in one approach to a behaviourally equivalent graph grammar in another approach. In this paper we translate graph grammars developed with the GROOVE tool to AGG graph grammars by first investigating the set of core graph transformation concepts supported by both tools. Then, we define what it means for two graph grammars to be behaviourally equivalent, and for the regarded approaches we actually show how to handle different definitions of both- application conditions and graph structures. The translation itself is explained by means of intuitive examples