Analyzing Consistency of Formal Requirements

In the development of safety-critical embedded systems, requirements-driven approaches are widely used. Expressing functional requirements in formal languages enables reasoning and formal testing. This paper proposes the Simplified Universal Pattern (SUP) as an easy to use formalism and compares it to SPS, another commonly used specification pattern system. Consistency is an important property of requirements that can be checked already in early design phases. However, formal definitions of consistency are rare in literature and tent to be either too weak or computationally too complex to be applicable to industrial systems. Therefore this work proposes a new formal consistency notion, called partial consistency, for the SUP that is a trade-off between exhaustiveness and complexity. Partial consistency identifies critical cases and verifies if these cause conflicts between requirement

Enforcement of Patterns by Constraint-Aware Model Transformations

Patterns are descriptions and solutions for recurring problems in software design and implementation. In this paper, some ideas towards a formal approach to the specification of patterns in model-driven engineering (MDE) is presented. The approach is based on the Diagram Predicate Framework which provides a formal approach to (meta)modelling, model transformation and model management in MDE. In particular, patterns are defined as diagrammatic specifications and constraint-aware model transformations are adapted to enforce patterns. Moreover, running examples are used to illustrate the facade design pattern in structural models

Replicode: A Constructivist Programming Paradigm and Language

Replicode is a language designed to encode short parallel programs and executable models, and is centered on the notions of extensive pattern-matching and dynamic code production. The language is domain independent and has been designed to build systems that are modelbased and model-driven, as production systems that can modify their own code. More over, Replicode supports the distribution of knowledge and computation across clusters of computing nodes. This document describes Replicode and its executive, i.e. the system that executes Replicode constructions. The Replicode executive is meant to run on Linux 64 bits and Windows 7 32/64 bits platforms and interoperate with custom C++ code. The motivations for the Replicode language, the constructivist paradigm it rests on, and the higher-level AI goals targeted by its construction, are described by Thórisson (2012), Nivel and Thórisson (2009), and Thórisson and Nivel (2009a, 2009b). An overview presents the main concepts of the language. Section 3 describes the general structure of Replicode objects and describes pattern matching. Section 4 describes the execution model of Replicode and section 5 describes how computation and knowledge are structured and controlled. Section 6 describes the high-level reasoning facilities offered by the system. Finally, section 7 describes how the computation is distributed over a cluster of computing nodes. Consult Annex 1 for a formal definition of Replicode, Annex 2 for a specification of the executive, Annex 3 for the specification of the executable code format (r-code) and its C++ API, and Annex 4 for the definition of the Replicode Extension C++ API

A Modeling and Formal Approach for the Precise Specification of Security Patterns

International audienceNon-functional requirements such as Security and Dependability (S &D) become more important as well as more difficult to achieve. In fact, the integration of security features requires the availability of both application domain specific knowledge and security expertise at the same time. Hence, capturing and providing this expertise by the way of security patterns can support the integration of S&D features by design to foster reuse during the process of software system development.The solution envisaged here is based on combining metamodeling techniques and formal methods to represent security pattern at two levels of abstraction fostering reuse during the process of pattern development and during the process of pattern-based development. The contribution of this work is twofold: (1) An improvement of our previous pattern modeling language for representing security pattern in the form of a subsystem providing appropriate interfaces and targeting security properties, (2) Formal specification and validation of pattern properties, using the interactive Isabelle/HOL proof assistant. The resulting validation artifacts may mainly complete the definitions, and provide semantics for the interfaces and the properties in the context of S&D. As a result, validated patterns will be used as bricks to build applications through a Model-Driven engineering approach

The ModelCC Model-Driven Parser Generator

Syntax-directed translation tools require the specification of a language by means of a formal grammar. This grammar must conform to the specific requirements of the parser generator to be used. This grammar is then annotated with semantic actions for the resulting system to perform its desired function. In this paper, we introduce ModelCC, a model-based parser generator that decouples language specification from language processing, avoiding some of the problems caused by grammar-driven parser generators. ModelCC receives a conceptual model as input, along with constraints that annotate it. It is then able to create a parser for the desired textual syntax and the generated parser fully automates the instantiation of the language conceptual model. ModelCC also includes a reference resolution mechanism so that ModelCC is able to instantiate abstract syntax graphs, rather than mere abstract syntax trees.Comment: In Proceedings PROLE 2014, arXiv:1501.0169

Transforming timing diagrams into knowledge acquisition in automated specification

Requirements engineering is an important part of developing programs. It is an essential stage of the software development process that defines what a product or system should to achieve. The UML Timing diagram and Knowledge Acquisition in Automated Specification (KAOS) model are requirements engineering techniques. KAOS is a goal-oriented requirements approach while the Timing diagram is a graphical notation used for explaining software timing requirements. KAOS uses linear temporal logic (LTL) to describe time constraints in goal and operation models. Similarly, the Timing diagram can describe some temporal operators such as X (next), U (until) and R (release) over some period of time. Thus, our aim is to use the Timing diagram to generate parts of a KAOS model. In this paper we demonstrate techniques for creating a KAOS goal model from a Timing diagram. The Timing diagram which is used in this paper is adapted from the UML 2.0 Timing diagram and includes features to support translation into KAOS. We use a case study of a Lift system as an example to explain the translation processes described here