Refinement Propagation. Towards Automated Construction of Visual Specifications.

Creation and transformation of visual specifications is driven by modeler’s design decisions. After a design decision has been made, the modeler needs to adjust the specification to maintain its correctness. The number of adjustments might make the design process tedious for large specifications. We are interested in techniques that will reduce the modeler’s obligation to control specification correctness. Every single transformation of the visual specification can be captured by the notion of refinement used in formal methods. In this work we present the technique that supports a stepwise refinement of visual specifications based on calculations. We use refinement calculus as a logic for reasoning about refinement correctness. When a design decision is made by the modeler, the necessary adjustments are calculated based on rules of refinement propagation. Refinement propagation can automate the specification adjustment and enforce its correctness

Formal aspects of component software

This is the pre-proceedings of 6th International Workshop on Formal Aspects of Component Software (FACS'09)

Formal semantics for refinement verification of entreprise models

In this dissertation we investigate how Business/IT alignment in enterprise models can be enhanced by using a software engineering stepwise refinement paradigm. To have an IT system that supports an enterprise and meets the enterprise business needs, management seeks to align business system with IT systems. Enterprise Architecture (EA) is the discipline that addresses the design of aligned business and IT systems. SEAM is an Enterprise Architecture method, developed in the Laboratory of Systemic Modeling (LAMS) at EPFL. SEAM defines a visual language for building an enterprise model of an organization. In this work, we develop a theory and propose a technique to validate an alignment between the system specifications expressed in the SEAM language. We base our reasoning on the idea that each system (an organization, a business system, or an IT system) can be modeled using a set of hierarchical specifications, explicitly related to each other. Considering these relations as refinement relations, we transform the problem of alignment validation into the problem of refinement verification for system specifications: we consider that two system specifications are aligned if one is correctly refines the other. Model-driven engineering (MDE) defines refinement as a transformation between two visual (or program) specifications, where a specification is gradually refined into an implementation. MDE, however, does not formalize refinement verification. Software engineering (SE) formalizes refinement for program specifications. It provides a theory and techniques for refinement verification. To benefit from the formal theories and the refinement verification techniques defined in SE, we extend the SEAM language with additional concepts (e.g. preconditions, postconditions, invariants, etc). This extension enables us to increase the precision of the SEAM visual specifications. Then we define a formal semantics for the extended SEAM modeling language. This semantics is based on first-order logic and set theory; it allows us to reduce the problem of refinement verification to the validation of a first-order logic formula. In software engineering, the tools for the automated analysis of program specifications are defined. To use these tools for refinement verification, we define a translation from SEAM visual specifications to formal specification languages. We apply, using case studies, our theory and technique in several problem areas to verify: (1) if a business process design and re-design correspond to high level business process specifications; (2) if a service implementation corresponds to its specifications. These case studies have been presented to a group of domain experts who practice business/IT alignment. This inquiry has shown that our research has a potential practical value

An incremental process for the development of multi-agent systems in Event-B

A multi-agent system is a group of software or hardware agents that cooperate or compete to achieve individual or shared goals. A method for developing a multi-agent system must be capable of modelling the concepts that are central to multi-agent systems. These concepts are identified in a review of Agent Oriented Software Engineering methodologies. The rigorous development of complex systems using formal methods can reduce the number of design faults. Event-B is a formal method for modelling and reasoning about reactive and distributed systems. There is currently no method that guides the developer specifically in the modelling of agent-based concepts in Event-B. The use of formal methods is seen by some developers as inaccessible. This thesis presents an Incremental Development Process for the development of multi-agent systems in Event-B. Development following the Incremental Development Process begins with the construction of informal models, based on agent concepts. The informal models relate system goals using a set of relationships. The developer is provided with guidance to construct formal Event-B models based on the informal design. The concepts that are central to multi-agent systems are captured in the Event-B models through the translation from the goal models. The Event-B models are refined and decomposed into specifications of roles that will be performed by the agents of the system. Two case studies illustrate how the Incremental Development Process can be applied to multi-agent systems. An additional aid to the developer presented in this thesis is a set of modelling patterns that provide fault-tolerance for Event-B models of interacting agents.EThOS - Electronic Theses Online ServiceGBUnited Kingdo