Preface

Preface of the Proceedings of the Fourth International Workshop on Petri Nets and Graph Transformation PNGT 201

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

The Influence of the EU Environmental Management and Auditing Scheme on Environmental Innovations and Competitiveness in Germany: An Analysis on the Basis of Case Studies and a Large-Scale Survey

This paper investigates the effects of the EU Environmental Management and Auditing Scheme (EMAS) on environmental innovations and competitiveness in German facilities. It comprises twelve in-depth case studies and telephone interviews with 1277 EMAS-validated facilities. The surveys show a positive influence of EMAS on environmental organisational, process and product innovations. Moreover, the environmental report supports the diffusion of environmental innovations. The econometric analysis with binary probit models shows a significant positive impact of the maturity of environmental management systems on environmental innovations. Another determinant of environmental innovations is the strong participation of specific departments in further development of EMAS, especially of the R&D department. An effect of strategic importance of EMAS on market success could not be confirmed. Facilities with high learning processes by environmental management systems however have a significantly better performance concerning turnover and exports. --Environmental management systems,environmental innovation,technological progress,cleaner production

On Modelling Communication in Ubiquitous Computing Systems using Algebraic Higher Order Nets

Ubiquitous computing systems (UCSs) are designed to participate almostimperceptibly in everyday life. To ensure a solid operation, a UCS heavily depends on a reliable and efficient communication between its distributed computing components. Moreover components can join and leave the system at any time.In order to guarantee high quality systems, the use of models is inevitable especiallyat an early stage of the development process where models are the only possibilityto address a system which does not yet exist in reality. Petri nets and graph transformationsystems are established, theoretically well-founded concepts for modellingand analysing complex systems.This paper presents a formal approach for modelling core aspects of the communicationin UCSs by using Algebraic Higher Order Nets with Individual Tokens andgraph transformation. The approach is suitable to cover the different aspects ofcommunication and enables the analysis of specific properties. The approach and itssuitability are illustrated based on a running example. The feasibility of embeddingthe approach in a broader context of modelling is demonstrated in applying it to areal world system: the Living Place Hamburg

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

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

Layered Architecture Consistency for MANETs: Introducing New Team Members

In this paper we extend our results concerning the layered architecture for modeling workflows in Mobile Ad-Hoc networks (MANETs) using algebraic higher order nets. MANETs are networks of mobile devices that communicate with each other via wireless links without relying on an underlying infrastructure. 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. In fromer papers a formal notion of layer consistency was suggested, that we now extend to allow changes of the interfaces of the gluing of the workflow and the mobility layer

Der irrende Ritter – Künstler-, Kampf- und Kriegerromantik zum Ersten Weltkrieg

Kathrin Hoffmann-Curtius The Knight Errant. Romanticizing the Artist, Battle, and the Warrior in the World War One Era The article focuses on German paintings from the turn of the twentieth century to theWeimar Republic. Most notably before the First World War, painters, writers, and philosophers were attracted to the image of the lone, virtuous knight, representing unconquerable masculine power while excluding femininity and sexual life. With regard to the history of interpreting Albrecht Dürer’s famous engraving “Ritter, Tod und Teufel”, the article explores how Hans Thoma, Max Slevogt, Lovis Corinth, Oskar Kokoschka, and Paul Klee perform and deconstruct the knight’s heroic masculinity before and after the war