Asset Administration Shell as an interoperable enabler of Industry 4.0 software architectures: a case study

In recent years, the discipline of Digital Transformation in manufacturing companies turned out to be a hot topic of research debate, which allowed the design and introduction of new technologies and tools able to exploit the potential of the data produced by the shop floor assets. This increased interest in data generation and management has however highlighted a crucial issue about the lack of standardised models and structures to share these data and ensure interoperability. Among the several concepts proposed by the recent initiatives devoted to solving or mitigating this issue, Asset Administration Shell (AAS) is increasing in popularity, given its potential in providing standardised and modular information about the assets and events represented. This paper deals with a demonstration of the easiness of integration of AAS in pre-existing software architecture, allowing higher flexibility and a better understanding of the ongoing processes: a production line has been indeed entirely represented with modular AAS metamodels and it has been used to feed a Digital Model representing the line configuration. The use case proposed proves the effectiveness of the obtained solution when used for virtual commissioning operations

A Domain-Specific Language and Editor for Parallel Particle Methods

Domain-specific languages (DSLs) are of increasing importance in scientific high-performance computing to reduce development costs, raise the level of abstraction and, thus, ease scientific programming. However, designing and implementing DSLs is not an easy task, as it requires knowledge of the application domain and experience in language engineering and compilers. Consequently, many DSLs follow a weak approach using macros or text generators, which lack many of the features that make a DSL a comfortable for programmers. Some of these features---e.g., syntax highlighting, type inference, error reporting, and code completion---are easily provided by language workbenches, which combine language engineering techniques and tools in a common ecosystem. In this paper, we present the Parallel Particle-Mesh Environment (PPME), a DSL and development environment for numerical simulations based on particle methods and hybrid particle-mesh methods. PPME uses the meta programming system (MPS), a projectional language workbench. PPME is the successor of the Parallel Particle-Mesh Language (PPML), a Fortran-based DSL that used conventional implementation strategies. We analyze and compare both languages and demonstrate how the programmer's experience can be improved using static analyses and projectional editing. Furthermore, we present an explicit domain model for particle abstractions and the first formal type system for particle methods.Comment: Submitted to ACM Transactions on Mathematical Software on Dec. 25, 201

mRUBiS: An Exemplar for Model-Based Architectural Self-Healing and Self-Optimization

Self-adaptive software systems are often structured into an adaptation engine that manages an adaptable software by operating on a runtime model that represents the architecture of the software (model-based architectural self-adaptation). Despite the popularity of such approaches, existing exemplars provide application programming interfaces but no runtime model to develop adaptation engines. Consequently, there does not exist any exemplar that supports developing, evaluating, and comparing model-based self-adaptation off the shelf. Therefore, we present mRUBiS, an extensible exemplar for model-based architectural self-healing and self-optimization. mRUBiS simulates the adaptable software and therefore provides and maintains an architectural runtime model of the software, which can be directly used by adaptation engines to realize and perform self-adaptation. Particularly, mRUBiS supports injecting issues into the model, which should be handled by self-adaptation, and validating the model to assess the self-adaptation. Finally, mRUBiS allows developers to explore variants of adaptation engines (e.g., event-driven self-adaptation) and to evaluate the effectiveness, efficiency, and scalability of the engines

Modularization Approaches in the Context of Monolithic Simulations

Qualitätsmerkmale eines Software-Systems wie Zuverlässigkeit oder Performanz können über dessen Erfolg oder Scheitern entscheiden. Diese Qualitätsmerkmale können im klassischen Software-Ingenieurswesen erst bestimmt werden, wenn der Entwurfsprozess bereits vollendet ist und Teile des Software-Systems implementiert sind. Computer-Simulationen erlauben es jedoch Schätzungen dieser Werte schon während des Software-Entwurfs zu bestimmen. Simulationen werden erstellt um bestimmte Aspekte eines Systems zu analysieren. Die Repräsentation des Systems ist auf diese Analyse spezialisiert. Diese Spezialisierung resultiert oft in einer monolithischen Struktur der Simulation. Solch eine Struktur kann jedoch die Wartbarkeit der Simulation negativ beeinflussen und das Verständnis und die Wiederverwendbarkeit der Repräsentation des Systems verschlechtern. Die Nachteile einer monolithischen Struktur können durch das Konzept der Modularisierung reduziert werden. In diesem Ansatz wird ein Problem in kleinere Teilprobleme zerlegt. Diese Zerlegung ermöglicht ein besseres Veständnis und eine bessere Handhabung der Teilprobleme. In dieser Arbeit wird ein Ansatz präsentiert, um die Kopplung von neu entwickelten oder bereits existierenden Simulationen zu einer modularen Simulation zu beschreiben. Dieser Ansatz besteht aus einer Domänenspezifischen Sprache (DSL), die mit modellgetriebenen Technologien entwickelt wird. Die DSL wird in einer Fallstudie angewendet, um die Kopplung von zwei Simulationen zu beschreiben. Weiterhin wird die Kopplung dieser Simulationen mit einem existierenden Kopplungsansatz gemäß der erzeugten Beschreibung manuell implementiert. In dieser Fallstudie wird die Vollständigkeit der Fähigkeit der DSL untersucht, die Kopplung von mehreren Simulation zu einer modularen Simulation zu beschreiben. Weiterhin wird die Genauigkeit des Modularisierungsansatzes bezüglich der Verhaltensbewahrung der modularen Simulation gegenüber der monolithischen Version evaluiert. Hierfür werden die Resultate der modularen Simulation mit denen der monolithischen Version verglichen. Zudem wird die Skalierbarkeit des Ansatzes durch die Betrachtung der Ausführungszeiten untersucht, wenn mehrere Simulationen gekoppelt werden. Außerdem wird der Effekt der Modularisierung auf die Ausführungszeit in Relation zur monolithischen Simulation betrachtet. Die erhaltenen Resultate zeigen, dass die Kopplung der beiden Simulationen der Fallstudie, mit der DSL beschrieben werden kann. Die Resultate bezüglich der Evaluation der Genauigkeit weisen Probleme bei der Interaktion der Simulationen mit dem Kopplungsansatz auf. Nichts desto trotz bleibt das Verhalten der monolithischen Simulation in der modularen Version insgesamt erhalten. Die Evaluation zeigt, dass die modulare Simulation eine Erhöhung der Ausführungszeit im Vergleich zur monolithischen Version erfährt. Zudem deutet die Analyse der Skalierbarkeit darauf hin, dass die Ausführungszeit der modularen Simulation nicht exponentiell mit der Anzahl der gekoppelten Simulationen wächst

Model-driven performance analysis of rule-based domain specific visual models

Context: Domain-Specific Visual Languages (DSVLs) play a crucial role in Model-Driven Engineering (MDE). Most DSVLs already allow the specification of the structure and behavior of systems. However, there is also an increasing need to model, simulate and reason about their non-functional properties. In particular, QoS usage and management constraints (performance, reliability, etc.) are essential characteristics of any non-trivial system. Objective: Very few DSVLs currently offer support for modeling these kinds of properties. And those which do, tend to require skilled knowledge of specialized notations, which clashes with the intuitive nature of DSVLs. In this paper we present an alternative approach to specify QoS properties in a high-level and platform-independent manner. Method: We propose the use of special objects (observers) that can be added to the graphical specification of a system for describing and monitoring some of its non-functional properties. Results: Observers allow extending the global state of the system with the variables that the designer wants to analyze, being able to capture the performance properties of interest. A performance evaluation tool has also been developed as a proof of concept for the proposal. Conclusion: The results show how non-functional properties can be specified in DSVLs using observers, and how the performance of systems specified in this way can be evaluated in a flexible and effective way.Ministerio de Ciencia e Innovación TIN2008-031087Ministerio de Ciencia e Innovación TIN2011-2379

Metamodel-based model conformance and multiview consistency checking

Model-driven development, using languages such as UML and BON, often makes use of multiple diagrams (e.g., class and sequence diagrams) when modeling systems. These diagrams, presenting different views of a system of interest, may be inconsistent. A metamodel provides a unifying framework in which to ensure and check consistency, while at the same time providing the means to distinguish between valid and invalid models, that is, conformance. Two formal specifications of the metamodel for an object-oriented modeling language are presented, and it is shown how to use these specifications for model conformance and multiview consistency checking. Comparisons are made in terms of completeness and the level of automation each provide for checking multiview consistency and model conformance. The lessons learned from applying formal techniques to the problems of metamodeling, model conformance, and multiview consistency checking are summarized

The Promises and Perils of Agent-Based Computational Economics

In this paper I analyse the main strengths and weaknesses of agent-based computational models. I first describe how agent-based simulations can complement more traditional modelling techniques. Then, I rationalise the main theoretical critiques against the use of simulation, which point to the following problematic areas: (i) interpretation of the simulation dynamics, (ii) estimation of the simulation model, and (iii) generalisation of the results. I show that there exist solutions for all these issues. Along the way, I clarify some confounding differences in terminology between the computer science and the economic literature.Agent-based, Simulation, Microsimulation, Computational Economics, Structural Estimation, Economic methodology