Dominik Schmitz

Cyclodextrin modified microgels as “nanoreactor” for the generation of Au nanoparticles with enhanced catalytic activity

We report a facile and green method for the fabrication of hybrid microgels by the immobilization of catalytically active Au nanoparticles in α-cyclodextrin (α-CD) modified poly(N-vinylcaprolactam) (PVCL) microgels without addition of reducing agent and surfactant. It has been shown that only in the case of α-CD modified microgels metal particles were immobilized inside the colloidal gels, which is due to a coordination of the cyclodextrin molecules to the surface of Au nanoparticles. The PVCL-α-CD-Au composite particles can work efficiently as catalyst for the reduction of aromatic nitro-compounds by using the reduction of 4-nitrophenol (Nip) and 2,6-dimethyl-4-nitrophenol (DMNip) as model reactions. Most importantly, due to the selective binding ability of α-CDs to certain reagents, the synthesized hybrid microgels show different catalytic activity for the target compounds during the catalytic reactions: a significant enhancement in the catalytic activity has been observed for the reduction of Nip, while no obvious effect has been found for the reduction of DMNip.

Deliberation in a metadata-based modeling and simulation environment for inter-organizational networks

In the emerging field of database centric business process management, inter-organizational networks of people, information and communication systems are often described by the interplay between individual goals and actions and the strategic dependencies among individuals and subgroups. Our research aims at improving requirements engineering for such networks by not just representing these goals and dependencies statically, but also by studying the dynamic interactions between both. In previous work, we proposed the prototype environment SNet for the representation and dynamic simulation of agent-based designs for inter-organizational networks. A key feature of SNet was the automatic translation of extended i* models into the action language ConGolog. While this allowed the simulation of agent networks specified in i*, the resulting agents were purely reactive. In this paper, we explicitly incorporate deliberation into the agent design of SNet. At the level of i* deliberation is represented in terms of goals which are satisfiable by different tasks or agents. Utilities are modeled, in part, using the existing concept of softgoals, which are given a quantitative interpretation. At the level of ConGolog, decision-theoretic features are built into the interpreter, which drives the simulations, and the process of delegating tasks to other agents is explicitly represented.

Deliberation in a modeling and simulation environment for inter-organizational networks

Inter-organizational networks of people, information and communication systems are often described by the interplay between individual goals and actions and the strategic dependencies among individuals and subgroups. Our research aims at improving requirements engineering for such networks by not just representing these goals and dependencies statically, but also by studying the dynamic interactions between both. In previous work, we proposed the prototype environment SNet for the representation and dynamic evaluation of agent-based designs for inter-organizational networks. A key feature of SNet was the automatic translation of extended i* models into the action language ConGolog. While this allowed the simulation of agent networks specified in i*, the resulting agents were purely reactive, which limits the usefulness of the system, in particular as a decision-support tool for network members, who need to evaluate the utility of different courses of action. In this paper we propose to remedy the situation by explicitly incorporating deliberation into the agent design of SNet. At the level of i*, deliberation is represented in terms of goals which are satisfiable by different tasks or agents. Utilities are modeled, in part, using the existing concept of softgoals, which are given a quantitative interpretation. At the level of ConGolog, decision-theoretic features are built into the interpreter, which drives the simulations, and the process of delegating tasks to other agents is explicitly represented.

Mapping Requirement Models to Mathematical Models in Control System Development

When developing control systems software, mathematically based modelling tools such as Matlab/Simulink are used for design, simulation, and implementation. Thus, a continuous model-based approach does not need to map requirements to, for example, UML class diagrams but to this mathematical representation. In this paper, we build on previous work that has applied the requirements formalism i* to the development of control systems software and present a mapping from i* models to Matlab/Simulink models. During a first manual transformation step, design alternatives are resolved. The second, automated step generates a Matlab/Simulink skeleton model from the i* model. Finally, an interactive step allows incorporating existing hardware and platform components into the skeleton. As a running example, we consider the development of a parking assistant.

Evolution in Domain Model-Based Requirements Engineering for Control Systems Development

When developing software-based control systems, knowledge and experiences in the relevant domain are of great importance. Small- and medium-sized enterprises (SMEs) that are most active here need to capture requirements under severe time and costs pressures. In previous work we have shown that a domain model based on the requirements formalism i* accelerates the requirements capture. Furthermore, the domain model-based similarity search supports the detection of reusable components from earlier projects. But due to the innovativeness, flexibility, and customer-orientation of control systems development, this domain model is subject to continuous change. Within this paper, we investigate the effects of model evolution on our domain model-based requirements engineering approach. Building on examples from industrial practice, we develop a classification of possible domain model modifications. For each such class, we analyze its impact on the similarity search and derive appropriate counter measures to limit these harmful impacts.

Gemeinsamkeiten und Unterschiede der Prozess- und Fertigungstechnik

Zusammenfassung In der industriellen Produktion haben sich diskrete Fertigung und Prozesstechnik als weitgehend getrennte Domänen herausgebildet. Immer häufiger erfordern heutzutage jedoch sowohl Entwicklungssystematiken als auch konkrete Produktionsanforderungen die Integration der unterschiedlichen Systeme und Modelle. Als Voraussetzung für eine domänenübergreifende, bessere Integration bis hin zur Steuerung hybrider Produktionsanlagen werden in diesem Beitrag physikalische Grundlagen, technische Aufgabenstellungen aber auch entwickelte Modelle und Systeme beider Domänen vergleichend beschrieben und analysiert. Abstract Within the field of industrial production, discrete production and process technology have been established as mostly separated domains. Today´s development systematics and production requirements very often ask for an integration of the separated considerations in particular models. As a necessary presumption to enable a better, interdisciplinary integration up to an integrated automation control for hybrid plants, this paper compares and analyses the physical background, the technical task breakdown as well as established models and systems of both domains.

How to Keep Domain Requirements Models Reasonably Sized

A domain model based requirements engineering approach has proven to be helpful when developing software

Telos: Representing Knowledge about Control Systems?

Telos is a formal knowledge representation language designed for the development of information systems. It has been successfully applied in many different software development projects. Although the development of control systems also includes software development, it constitutes a completely different application domain. An in-depth analysis of the development process results in a set of key characteristics of this domain. Based on this set we investigate in this paper whether the features of Telos and its implementation ConceptBase are also valuable to support the development of control systems. We first review the existing application of the Telosbased, agent- and goal-oriented language i* to requirements modelling for control systems. Then we examine carefully each single feature of Telos and ConceptBase regarding the support of the identified key characteristics. This investigation shows that nearly all characteristics are well supported and only very few require further enhancements of Telos and ConceptBase.

A model driven approach to engineering of flexible manufacturing system control software

Increasing the performance and flexibility of automated manufacturing systems is a key success factor for todays production companies. Flexible Manufacturing Systems (FMS) have proven to be particularly suitable in this regard since they support small lot sizes and high numbers of variants at the same time. The most important problems facing FMS are the huge expenditure of time and the high costs for “engineering” its control software. Engineering in this context refers to all aspects from planning the concrete production process, to assigning machines to control programs, to implementing software modules, and to testing the whole configuration. In this paper, we describe a model driven approach to support consistent engineering of FMS control software. It makes use of UML and customized UML metamodels for FMS-specific features, and includes a prototype implementation based on open source. We report on first experiences with a real FMS running cosmos 4, a distributed, agent-oriented FMS control software.

Comparing three formal analysis approaches of the tropos family

Tropos is a software development methodology founded on concepts used to model early requirements, the i* framework. In addition to a methodological framework, research addresses also formal analysis support. In previous work, we proposed the prototype environment SNet based on the Trust-Confidence-Distrust (TCD) approach for the representation and dynamic evaluation of agent-based designs for inter-organizational networks. There are two major ingredients: i* for modeling the domain statically and ConGolog for analysing it dynamically via simulations. In this paper, we compare our approach with two other approaches that enrich i*/Tropos models to allow for more formal analyses, Formal Tropos and Secure Tropos. While the intended use of these is quite different from SNet, there are a number of commonalities, which will be highlighted as well as the differences that suggest a combined use, including complementary forms of analysis such as model checking versus simulation.