ALLOY MODEL

Alloy Model

Alloy Model

Introduction

This paper will analyse the use of Alloy model checker for a Reference Model for Open Distributed Processing. The paradigm characterises a meta-modelling structure effective in the scope of general scheme modelling, in specific for object-oriented frameworks. This structure is rigorous and at the identical time flexible. It permits the delineation of prescribed ontologies for diverse exact object-oriented structures, for demonstration for "Unified Modelling Language" (UML) or for "Reference Model of Open Distributed Processing" (RM-ODP is an ISO/ITU standard). Thus distinct living structures, like UML or RM-ODP, can advantage from the ordered rigor, interior consistency, understanding coherency, prescribed production and solid theoretical bases of the characterised paradigm. Adoption of this paradigm permits the tenacity of vital difficulties living in these distinct object-oriented frameworks. (Jackson 2008:65-85)

The paradigm is formally offered and recognized in a computer-interpretable pattern on the demonstration of ontology recounting the RM-ODP conceptual framework.

Thus the paradigm recognizes a significant outcome that was not ever accomplished previously a lone reliable formalization of the RM-ODP benchmark conceptual framework.

This formalization presents a solid demonstration of prescribed ontology for general scheme modelling. The paradigm is furthermore directed on UML. This submission permitted the production of theoretical bases that are essential for the comprehending and delineation of the UML metamodel.

Informal Overview Of The Subject

Formal methods provide a syntactic domain (i.e. the notation or set of symbols of the method), a semantic domain (like its universe of objects), and a set of precise rules defining how an object can satisfy a specification. Most formal methods are supported by one or more tools. These, based on the characteristics of each formal method, can be categorized as theorem provers and model checkers.

There is a slightly different category of tools such as the Alloy analyzer which is sometimes defined as a model finder. This kind of tool works by finding models that form counterexamples to assertions made by the user: "Its engine takes a formula and attempts to find a model of it". Alloy by Jackson and Paradox by Claessen et al. (2003) are examples of a program that implements techniques for finding finite models based on first order logic, whilst model checking is based on temporal logic(Claessen:15-20).

In Jackson's (2008)words "Alloy is an attempt to combine the best features of Z and the Object Constraint Language of UML in a lightweight notation (Jackson 2008:65-85). It takes UML's emphasis on binary relations, and the expression of constraints with sets of objects formed by 'navigations', but with Z's much simpler semantics." (Brodsky 2005:110-120)

The essential idea about Alloy can be summarized as follows. The authors can build a micro-model with Alloy using signatures and formula paragraphs (i.e. predicates, functions, or assertions). Once the model is compiled, the authors can check every assertion with the intention of finding a counterexample. In other words, the Alloy analyzer looks for some instance of our micro-model that could be generated in violation of the assertions. It is for this reason that Jackson (2009) says in that Alloy follows a refutation ...