Graphs as Models combines the strengths of two preexisting workshop series: GTVMT (Graph Transformation and Visual Modelling Techniques) and GRAPHITE (Graph Inspection and Traversal Engineering), but also solicits research from other related areas, such as social network analysis.
Graphs as Models offers a plattform for exchanging new ideas and results for active researchers in these areas, and is a satellite workshop of ETAPS 2016.
Graphs are used as models in all areas of computer science: examples are state space graphs, control flow graphs, syntax graphs, UMLtype models of all kinds, network layouts, social networks, dependency graphs, and so forth. Once such graphical models are constructed, they can be analysed and transformed to verify their correctness within a domain, discover new properties, or produce new equivalent and/or optimised versions.
Graphs as Models’ main focus is the exchange and collaboration of researchers from different backgrounds. The workshop serves as platform to boost inter and transdisciplinary research and wants to serve as leeway for new ideas. Thus, besides classical research presentations, the workshop is highly geared toward numerous interactive sessions.
Graphs as Models’ main focus is the exchange and collaboration of researchers from different backgrounds. The workshop serves as platform to boost inter and transdisciplinary research and wants to serve as leeway for new ideas. Thus, besides classical research presentations, the workshop is highly geared toward numerous interactive sessions.
This is a oneandahalf workshop programmed as mixture of
This workshop seeks to attract and stimulate research on the techniques for graph analysis, inspection and transformation, on an abstract level rather than in any specific domain. Thus, the concept of a graph (in its many guises) is central; contributions should address scenarios for the use of graphs in a modelling context that potentially transcend specific settings and can be applied across domains. We welcome contributions on any of the following (nonexhaustive) list of topics:
The workshop seeks submissions of several kinds:
13:50  Welcome (workshop chairs) 
14:00  An EMOFCompliant Abstract Syntax for Bigraphs (T. Kehrer, C. Tsigkanos, C. Ghezzi)
Bigraphs are an emerging modeling formalism for structures in ubiquitous computing. Besides an algebraic notation, which can be adopted to provide an algebraic syntax for bigraphs, the bigraphical theory introduces a visual concrete syntax which is intuitive and unambiguous at the same time; the standard visual notation can be customized and thus tailored to domainspecific requirements. However, in contrast to modeling standards based on the MetaObject Facility (MOF) and domainspecific languages typically used in modeldriven engineering (MDE), the bigraphical theory lacks a precise definition of an abstract syntax for bigraphical modeling languages. As a consequence, available modeling and analysis tools use proprietary formats for representing bigraphs internally and persistently, which hampers the exchange of models across tool boundaries. Moreover, tools can be hardly integrated with standard MDE technologies in order to build sophisticated tool chains and modeling environments, as required for systematic engineering of large systems or fostering experimental work to evaluate the bigraphical theory in realworld applications. To overcome this situation, we propose an abstract syntax for bigraphs which is compliant to the Essential MOF (EMOF) standard defined by the Object Management Group (OMG). We use typed graphs as a formal underpinning of EMOFbased models and present a canonical mapping which maps bigraphs to typed graphs in a natural way. We also discuss applicationspecific variation points in the graphbased representation of bigraphs. Following standard techniques from software product line engineering, we present a framework to customize the graphbased representation to support a variety of application scenarios.
slides 
14:30  Grammar transformation with DPO rewriting (A. Kissinger, V. Zamdzhiev)
We develop a framework for the transformation of vertexreplacement grammars by means of doublepushout rewriting. We first give a simple construction of a category whose objects are (a mild generalisation of) socalled `edNCE' vertexreplacement grammars and prove this category is adhesive. From this we automatically obtain the notion of grammar rewrite rule, which represents a contextfree language of graph rewrite rules. By extending the familiar `no dangling' conditions of graph matching, we obtain a notion of grammar rewriting which is sound in the sense that every graph in the resulting grammar can be obtained by one or more applications of a rules in the language of the grammar rewrite rule. In this workinprogress report, we give sufficient conditions for soundness of the matching, and sketch a proof.
slides 
15:00  Incremental View Maintenance for Deductive Graph DBs using Generalized Discrimination Networks (T. Beyhl, H. Giese)
Nowadays, graph databases are employed when relationships between entities are in the scope of database queries to avoid performancecritical join operations of relational databases. Graph queries are used to query and modify graphs stored in graph databases. Graph queries employ graph pattern matching that is NPcomplete for subgraph isomorphism. Graph database views can be employed that keep ready answers in terms of precalculated graph pattern matches for often stated and complex graph queries to increase query performance. However, such graph database views must be kept consistent with the graphs stored in the graph database.
In this paper, we describe how to use incremental graph pattern matching as technique for maintaining graph database views. We present an incremental maintenance algorithm for graph database views, which works for imperatively and declaratively specified graph queries. The evaluation shows that our maintenance algorithm scales when the number of nodes and edges stored in the graph database increases. Furthermore, our evaluation shows that our approach can outperform ordinary approaches for incremental maintenance of graph database views.

15:30  Coffee break 
16:00  Agile Data Integration in Graph Databases using TripleGraph Grammars (A. Alqahtani, A. Boronat, R. Heckel)
Graph databases such as Neo4J provide a scalable semistructured data store based on a simple and flexible graph data model and powerful but complex query language. They perform well without requiring a static schema, but leave it to the application level to ensure type safety of update operations. We propose to describe query and update operations on graph databases by graph transformation rules and especially use TGGs to model the synchronisation of data from different sources.
whiteboardshot 
16:30  Administration / Working Groups: Introduction & Planning 
17:00  Graphs as Models: Panel Discussion 
(Inofficial GaM Diner, to be detailed) 
9:00  Invited Talk/Tutorial: Controlled Graph Rewriting — Illustrated in GROOVE (A. Rensink) 
10:00  Coffee break 
10:30  Type annotation for adaptive systems (P. Bottoni, A. Fish, F. ParisiPresicce)
We introduce the notion of type annotation as a way to provide a flexible typing mechanism for graph systems and discuss its advantages with respect to classical typing based on graph morphisms. In the new proposal the type system is incorporated with the graph and elements can adapt to changes in context by changing their types. We briefly sketch a number of case studies in which this mechanism is actually relevant.
slides 
11:00  Graph Grammar for Modeling RNA Folding Evolution as a SelfAdaptive System (A.L. Mamuye, E. Merelli, L. Tesei)
We propose a new approach for modelling the process of RNA folding as a graph transformation guided by the global value of free energy. Since the folding process evolves towards a configuration in which the free energy is minimal, the global behaviour resembles the one of a selfadaptive system. Each RNA configuration is a graph and the evolution of configurations is constrained by precise rules that can be described by a graph grammar.
slides 
11:30  Towards a Step Semantics for StoryDriven Modelling (G. Kulcsár, A. Anjorin)
Graph Transformation (GraTra) provides a formal, declarative means of specifying model transformations.
In practice, GraTra rule applications are often programmed via an additional language with which the order of rule applications can be suitably controlled.
StoryDriven Modelling (SDM) is a language implementing programmed GraTra, originally being part of the Fujaba tool suite. Using an intuitive, UMLinspired visual syntax, SDM introduces usual imperative control flow constructs such as sequences and conditionals which are fairly simple, but whose interaction with individual GraTra rules is nonetheless nontrivial. In this paper, we present the first results of our ongoing work towards providing a formal step semantics for SDM which focuses on the execution of an SDM specification. We use GraTra as a metalanguage for the formalisation. slides 
12:00  A Graphbased Game to Negotiate Features (M. Alabdullatif, R. Heckel)
We consider a (turnbased) stochastic game specified by a graph transformation system modelling the negotiation of features over a feature model. Following the generation of the relevant transition system, a PRISM game can be extracted for analysis and synthesis of strategies. These can be used to evaluate or implement negotiators, e.g., as part of the development of a flexible ecommerce application.
slides 
12:30  Lunch break 
14:00  An Improved Language for High Level Control Flow Semantics Definition (R. Gankema, A. Rensink)
This paper presents CFSL+, which is based on CFSL, a visual language for the specification of control flow in programming languages. In contrast to CFSL, the notation of CFSL+ was designed specifically with readability in mind. To achieve this, a set of design principles called the "Physics of Notations" was used. These principles, based on theory and empirical evidence, provide a framework that can aid visual language designers in developing notations that are cognitively effective. A preliminary evaluation using these principles shows that CFSL+ is more effective at communicating information than CFSL, although a user evaluation is still required to confirm this. A mapping from CFSL+ to CFSL is also presented.
slides 
14:30  Working Groups: Discussions 
16:00  Coffee break 
16:30  Working Groups: Plenary discussion of outcome(s) 
17:00  Retrospective & Business (Workshop chairs) 
(Official ETAPS PreWorkshop Diner) 
For your queries and in case of problems with this web page, please contact the workshop chairs (gam2016easychair.org).