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Grunewald, Germany

Golas U.,Konrad Zuse Zentrum fur Informationstechnik Berlin | Lambers L.,University of Potsdam | Ehrig H.,TU Berlin | Orejas F.,Polytechnic University of Catalonia
Theoretical Computer Science | Year: 2012

Inheritance is an important and widely spread concept enabling the elegant expression of hierarchy in object-oriented software programs or models. It has been defined for graphs and graph transformations enhancing the applicability of this formal technique. Up to now, for the analysis of transformations with inheritance a flattening construction has been used, which yields all the well-known results for graph transformation but results in a large number of graphs and rules that have to be analyzed. In this paper, we introduce a new category of typed attributed graphs with inheritance. For the detection of conflicts between graph transformations on these graphs, the notion of abstract critical pairs is defined. This allows us to perform the analysis on polymorphic rules and transformations without the need for flattening, which significantly increases the efficiency of the analysis and eases the interpretation of the analysis results. The new main result is the Local Confluence Theorem for typed attributed graph transformation with inheritance using abstract critical pairs. All constructions and results are demonstrated on an example for the analysis of refactorings. © 2011 Elsevier B.V. All rights reserved. Source

Herschel M.,University of Tubingen | Naumann F.,Hasso Plattner Institute For Softwaresystemtechnik | Szott S.,Konrad Zuse Zentrum fur Informationstechnik Berlin | Taubert M.,BIOTRONIK SE and Co. KG
IEEE Transactions on Knowledge and Data Engineering | Year: 2012

Duplicate detection determines different representations of real-world objects in a database. Recent research has considered the use of relationships among object representations to improve duplicate detection. In the general case where relationships form a graph, research has mainly focused on duplicate detection quality/effectiveness. Scalability has been neglected so far, even though it is crucial for large real-world duplicate detection tasks. We scale-up duplicate detection in graph data (ddg) to large amounts of data and pairwise comparisons, using the support of a relational database management system. To this end, we first present a framework that generalizes the ddg process. We then present algorithms to scale ddg in space (amount of data processed with bounded main memory) and in time. Finally, we extend our framework to allow batched and parallel ddg, thus further improving efficiency. Experiments on data of up to two orders of magnitude larger than data considered so far in ddg show that our methods achieve the goal of scaling ddg to large volumes of data. © 2012 IEEE. Source

Cloet I.C.,University of Adelaide | Horsley R.,University of Edinburgh | Londergan J.T.,Indiana University Bloomington | Nakamura Y.,RIKEN | And 9 more authors.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

We present the first determination of charge symmetry violation (CSV) in the spin-dependent parton distribution functions of the nucleon. This is done by determining the first two Mellin moments of the spin-dependent parton distribution functions of the octet baryons from N f=2+1 lattice simulations. This exploratory work is performed using a single value of the lattice spacing and volume. The results are compared with predictions from quark models of nucleon structure. We discuss the contribution of partonic spin CSV to the Bjorken sum rule, which is important because the CSV contributions represent the only partonic corrections to the Bjorken sum rule. © 2012 Elsevier B.V. Source

Ehrig H.,TU Berlin | Golas U.,Konrad Zuse Zentrum fur Informationstechnik Berlin | Habel A.,University of Oldenburg | Lambers L.,University of Potsdam | Orejas F.,Polytechnic University of Catalonia
Mathematical Structures in Computer Science | Year: 2014

Nested application conditions generalise the well-known negative application conditions and are important for several application domains. In this paper, we present Local Church-Rosser, Parallelism, Concurrency and Amalgamation Theorems for rules with nested application conditions in the framework of $\mathcal{M}$-adhesive categories, where $\mathcal{M}$-adhesive categories are slightly more general than weak adhesive high-level replacement categories. Most of the proofs are based on the corresponding statements for rules without application conditions and two shift lemmas stating that nested application conditions can be shifted over morphisms and rules. © Cambridge University Press 2014. Source

Golas U.,Konrad Zuse Zentrum fur Informationstechnik Berlin | Habel A.,University of Oldenburg | Ehrig H.,TU Berlin
Mathematical Structures in Computer Science | Year: 2014

Amalgamation is a well-known concept for graph transformations that is used to model synchronised parallelism of rules with shared subrules and corresponding transformations. This concept is especially important for an adequate formalisation of the operational semantics of statecharts and other visual modelling languages, where typed attributed graphs are used for multiple rules with nested application conditions. However, the theory of amalgamation for the double-pushout approach has so far only been developed on a set-theoretical basis for pairs of standard graph rules without any application conditions. For this reason, in the current paper we present the theory of amalgamation for $\mathcal{M}$-adhesive categories, which form a slightly more general framework than (weak) adhesive HLR categories, for a bundle of rules with (nested) application conditions. The two main results are the Complement Rule Theorem, which shows how to construct a minimal complement rule for each subrule, and the Multi-Amalgamation Theorem, which generalises the well-known Parallelism and Amalgamation Theorems to the case of multiple synchronised parallelism. In order to apply the largest amalgamated rule, we use maximal matchings, which are computed according to the actual instance graph. The constructions are illustrated by a small but meaningful running example, while a more complex case study concerning the firing semantics of Petri nets is presented as an introductory example and to provide motivation. © Cambridge University Press 2014. Source

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