Modeling and Reasoning over Distributed Systems using Aspect-Oriented Graph Grammars

Aspect-orientation is a relatively new paradigm that introduces abstractions to modularize the implementation of system-wide policies. It is based on a composition operation, called aspect weaving, that implicitly modifies a base system by performing related changes within the system modules. Aspect-oriented graph grammars (AOGG) extend the classic graph grammar formalism by defining aspects as sets of rule-based modifications over a base graph grammar. Despite the advantages of aspect-oriented concepts regarding modularity, the implicit nature of the aspect weaving operation may also introduce issues when reasoning about the system behavior. Since in AOGGs aspect weaving is characterized by means of rule-based rewriting, we can overcome these problems by using known analysis techniques from the graph transformation literature to study aspect composition. In this paper, we present a case study of a distributed client-server system with global policies, modeled as an aspect-oriented graph grammar, and discuss how to use the AGG tool to identify potential conflicts in aspect weaving

The GROOVE Simulator: A Tool for State Space Generation

The tool described here is the first part of a tool set called GROOVE (GRaph-based Object-Oriented VErification) for software model checking of object-oriented systems. The special feature of GROOVE, which sets it apart from other model checking approaches, is that it is based on graph transformations. It uses graphs to represent state snapshots; transitions arise from the application of graph production rules. This yields so-called Graph Transition Systems (GTSrsquos) as computational models

Position Paper: Formal Methods in Agile Development

Modern software development must be agile. It has to accept that soft- ware systems undergo a lot of changes due to changes in the application context (for example changing conditions on the markets and changes due to the jurisdiction) and base technology (e.g. integration of new frameworks or updates of the platform) in their life cycle. Thus, most of the activities in the development process are redesign steps. Even requirements are not stable. They change in time as the context of the system changes. There is no time for complex correctness proofs of the implementation with respect to the requirements. Automatic (regression) testing has proved to be sufficient for correct system behaviour. Therefore the agile developer does not learn and apply formal methods himself. In order to be agile, however, he relies on tools for automatic refactoring of the system or of certain parts of it. These tools are able to change the system structure without changing its behaviour. We argue in this paper that, in order to build such tools, further research in the area of formal system modelling and development is needed

Categorical Abstract Rewriting Systems and Functoriality of Graph Transformation

Rewriting systems are often defined as binary relations over a given set of objects. This simple definition is used to describe various properties of rewriting such as termination, confluence, normal forms etc. In this paper, we introduce a new notion of abstract rewriting in the framework of categories. Then, we define the functoriality property of rewriting systems. This property is sometimes called vertical composition. We show that most of graph transformation systems are functorial and provide a counter-example of graph transformation systems which is not functorial

Principal manifolds and graphs in practice: from molecular biology to dynamical systems

We present several applications of non-linear data modeling, using principal manifolds and principal graphs constructed using the metaphor of elasticity (elastic principal graph approach). These approaches are generalizations of the Kohonen's self-organizing maps, a class of artificial neural networks. On several examples we show advantages of using non-linear objects for data approximation in comparison to the linear ones. We propose four numerical criteria for comparing linear and non-linear mappings of datasets into the spaces of lower dimension. The examples are taken from comparative political science, from analysis of high-throughput data in molecular biology, from analysis of dynamical systems.Comment: 12 pages, 9 figure

A Compositional Approach to Structuring and Refinement of Typed Graph Grammars

Abstract Based on a categorical semantics that has been developed for typed graph grammars we uses colimits (pushouts) to model composition and (reverse) graph grammar morphisms to describe refinements of typed graph grammars. Composition of graph grammars w.r.t. common subgrammars is shown to be compatible with the semantics, i.e. the semantics of the composed grammar is obtained as the composition of the semantics of the component grammars. Moreover, the structure of a composed grammar is preserved during a refinement step in the sense that compatible refinements of the components induce a refinement of the composition. The concepts and results are illustrated by an example

ขั้นตอนวิธีสำหรับการเข้ารหัสข้อมูลบนฐานข้อมูลแบบกระจาย

The objective of research was to develop analgorithm for cryptic distribute databases (ACDD) for distributed database management of the encrypted data to solve the problem of information leakage caused by fraud DBAs. The used techniques were Paillier homomorphic Polynomials ring, Shamir's Secret Sharing scheme and transformation graph. The Advantages of this algorithm were that it can solve the problem of dishonest dealers and dishonest participants who try to deceive other participants data and enables perform calculations on encrypted data without decryption on which the calculation was carried out, with respect of the data confidentiality

Modeling context with graph annotations

Organisational policies are often formed of declarational (defining constraints on functional services) and operational (realising functionalities via simple activities) aspects. However, when several perspectives are involved, constraints and operations can comprise different aspects, without identifying the origin of some details. We propose the use of annotations as a way to flexibly add and remove application conditions on rules, while maintaining an indication of their origin. We use graph transformations to model operations in some application domain, graph constraints to model conditions imposed by some external domain, and annotations to combine domains. We explore the problem of failure of transactions due to the additional constraints imposed by the contextual domain, and describe a way to redefine the success conditions for transactions employing the modified rules