Graph Transformations for the Resource Description Framework

The Resource Description Framework (RDF) is a standard developed by the World Wide Web Consortium (W3C) to facilitate the representation and exchange of structured (meta-)data in the "SemanticWeb". While there is a large body of work dealing with inference on RDF, a concept for transformation and manipulation is still missing. Since RDF uses graphs as a formal basis, this paper proposes the use of algebraic graph transformations with their wealth of well-known constructions and results for this purpose. It turns out that RDF graphs are an interesting application area for graph transformation methods, where some significant differences to classical graphs yield practically relevant solutions for features like attribution, typing and globally unique nodes

Rule-Based Integration of Domain-Specific Modelling Languages

Domain-specific modelling languages (DSMLs) can increase the acceptance of (semi-)formal modelling techniques. They allow all stakeholders in an application domain to participate in the modelling process using notations that are close to their understanding of the domain. When several groups of stakeholders are concerned with a certain aspect of the modelled system, the question arises how different DSMLs can be integrated with respect to this aspect. In this paper, we propose rule-based transformations as a means to integrate heterogeneous DSMLs overlapping on dedicated aspects. We illustrate the approach by a running example of a small visual DSML for IT landscapes and a textual DSML for firewall configurations

Conformance Analysis of Organizational Models in a new Enterprise Modeling Framework using Algebraic Graph Transformation - Extended Version

Organizational models play a key role in today's enterprise modeling. These models often show up as partial models produced by people with different conceptual understandings in a usually decentralized organization, where they are modeled in a distributed and non-synchronized fashion. For this reason, there is a first major need to organize partial organizational models within a suitable modeling framework, and there is a second major need to check their mutual conformance. This builds the basis to integrate the partial organizational models later on into one holistic model of the organization. Moreover, the partial models can be used for model checking certain security, risk, and compliance constraints. In order to satisfy the two major needs, this paper presents two mutually aligned contributions. The first one is a new enterprise modeling framework the EM-Cube. The second contribution is a new approach for checking conformance of models that are developed based on the suggested formal modeling technique associated with the proposed framework. In addition to that, we evaluate our potential solution against concrete requirements derived from a real-world scenario coming out of the finance industry

Sharing is Caring - Understanding the Relationship Between the Sharing Economy and Sustainable Mobility

Electric vehicles (EVs) could play a major role in making personal transportation more sustainable. Yet, their diffusion is slow and the general public is skeptical of their potential to replace conventional combustion vehicles (CVs). We investigate differences in driver behavior between the two types, showing how sharing economy approaches can help people overcome concerns related to electric mobility. We analyze a dataset of carsharing rentals of a provider who offers EVs and CVs under the same conditions, within the same city, comprising over 230,000 rentals of approximately 750 cars over a period of 3.5 months. Our preliminary results suggest that in fact, once people get acquainted with EVs – at least in an urban carsharing context – they use them in a very similar manner as they use CVs. This suggests that the sharing economy supports the adoption of electric mobility and fosters more sustainable transportation

Intermodal Mobility

Cities around the world are facing a multitude of mobility challenges. Driven by an increase in the number of personal motor vehicles, traffic and traffic congestion are becoming more frequent, parking spaces are becoming more scarce (while also taking up public space), and the urban population is increasingly exposed to air pollution and noise with potentially negative health effects (Arnott and Inci 2006; Arnott and Small 1994; Barth and Boriboonsomsin 2008; Loukopoulos et al. 2005). In addition to producing CO2 and other harmful emissions, personal cars are used inefficiently. It is estimated that they stand unused 95% of the time (Barter 2013) and, when driving, carry only 1.7 persons on average (US Department of Transportation 2011). At the same time, the number of people living in cities is expected to continually increase in both relative and absolute terms. The share of the urban population has been estimated to increase to 66% by 2050, up from 54% in 2014 (United Nations Department of Economic and Social Affairs 2014). Thus, the ongoing urbanization trend will likely exacerbate urban mobility challenges in the near future

Propagation of Constraints along Model Transformations Based on Triple Graph Grammars: Long Version

Model transformations based on triple graph grammars (TGGs) have been applied in several practical case studies and they convince by their intuitive and descriptive way of specifying bidirectional model transformations. Moreover, fundamental properties have been extensively studied including syntactical correctness, completeness, termination and functional behaviour. But up to now, it is an open problem how domain specific properties that are valid for a source model can be preserved along model transformations such that the transformed properties are valid for the derived target model. In this paper, we analyse in the framework of TGGs how to propagate constraints from a source model to an integrated and target model such that, whenever the source model satisfies the source constraint also the integrated and target model satisfy the corresponding integrated and target constraint. In our main new results we show under which conditions this is possible. The case study shows how this result is successfully applied for the propagation of security constraints in enterprise modelling between business and IT models

Enterprise Modelling using Algebraic Graph Transformation - Extended Version

An analysis of today's situation at Credit Suisse has shown severe problems, because it is based on current best practices and ad-hoc modelling techniques to handle important aspects of security, risk and compliance. Based on this analysis we propose in this paper a new enterprise model which allows the construction, integration, transformation and evaluation of different organizational models in a big decentralized organization like Credit Suisse. The main idea of the new model framework is to provide small decentralized models and intra-model evaluation techniques to handle services, processes and rules separately for the business and IT universe on one hand and for human-centric and machine-centric concepts on the other hand. Furthermore, the new framework provides inter-modelling techniques based on algebraic graph transformation to establish the connection between different kinds of models and to allow integration of the decentralized models. In order to check for security, risk and compliance in a suitable way, our models and techniques are based on different kinds of formal methods. In this paper, we show that algebraic graph transformation techniques are useful not only for intra-modelling - using graph grammars for visual languages and graph constraints for requirements - but also for inter-modelling - using triple graph grammars for model transformation and integration. Altogether, we present the overall idea of our new model framework and show how to solve specific problems concerning intra- and inter-modelling as first steps. This should give evidence that our framework can also handle important other requirements for enterprise modelling in a big decentralized organization like Credit Suisse