An experimental scrutiny of visual design modelling: VCL up against UML+OCL

in Empirical Software Engineering (2019)

The graphical nature of prominent modelling notations, such as the standards UML and SysML, enables them to tap into the cognitive benefits of diagrams. However, these notations hardly exploit the ... [more ▼]

The graphical nature of prominent modelling notations, such as the standards UML and SysML, enables them to tap into the cognitive benefits of diagrams. However, these notations hardly exploit the cognitive potential of diagrams and are only partially graphical with invariants and operations being expressed textually. The Visual Contract Language (VCL) aims at improving visual modelling; it tries to (a) maximise diagrammatic cognitive effectiveness, (b) increase visual expressivity, and (c) level of rigour and formality. It is an alternative to UML that does largely pictorially what is traditionally done textually. The paper presents the results of a controlled experiment carried out four times in different academic settings and involving 43 participants, which compares VCL against UML and OCL and whose goal is to provide insight on benefits and limitations of visual modelling. The paper’s hypotheses are evaluated using a crossover design with the following tasks: (i) modelling of state space, invariants and operations, (ii) comprehension of modelled problem, (iii) detection of model defects and (iv) comprehension of a given model. Although visual approaches have been used and advocated for decades, this is the first empirical investigation looking into the effects of graphical expression of invariants and operations on modelling and model usage tasks. Results suggest VCL benefits in defect detection, model comprehension, and modelling of operations, providing some empirical evidence on the benefits of graphical software design. [less ▲]

Assessing Composition in Modeling Approaches

in Proceedings of the CMA 2012 Workshop (2012, December)

Modeling approaches are based on various paradigms, e.g., aspect-oriented, feature-oriented, object-oriented, and logic-based. Modeling approaches may cover requirements models to low level design models ... [more ▼]

Modeling approaches are based on various paradigms, e.g., aspect-oriented, feature-oriented, object-oriented, and logic-based. Modeling approaches may cover requirements models to low level design models, are developed for various purposes, use various means of composition, and thus are difficult to compare. However, such comparisons are critical to help practitioners know under which conditions approaches are most applicable, and how they might be successfully generalized and combined to achieve end-to-end methods. This paper reports on work done at the 2nd International Comparing Modeling Approaches (CMA) workshop towards the goal of identifying potential comprehensive modeling methodologies with a particular emphasis on composition: (i) an improved set of comparison criteria; (ii) 19 assessments of modeling approaches based on the comparison criteria and a common, focused case study. [less ▲]

Modelling a cardiac pacemaker visually and formally

in VLHCC 2012 (2012)

Embedded software in medical devices is becoming ubiquitous and increasing in content and complexity. This paper gives an outline of a visual model of a cardiac pacemaker system, a case study from the ... [more ▼]

Embedded software in medical devices is becoming ubiquitous and increasing in content and complexity. This paper gives an outline of a visual model of a cardiac pacemaker system, a case study from the grand challenge in software verification. The model is expressed in the Visual Contract Language (VCL), a formal modelling language that describes predicates visually. From VCL diagrams it is possible to generate Z specifications. This is the first visual and formal model of one of the software verification challenges. [less ▲]

Automated Generation of Platform-Variant Applications from Platform-Independent Models via Templates

in Electronic Notes in Theoretical Computer Science (2011), 279(3), 3-25

Model-driven development raises the level of abstraction so that software engineers can focus on design rather than implementation and platform-specific details. This paper presents a model-centric ... [more ▼]

Model-driven development raises the level of abstraction so that software engineers can focus on design rather than implementation and platform-specific details. This paper presents a model-centric approach to MDD, where platform code is generated from a platform-independent model describing platform-variant families of products. The generation is done via templates; the variation point lies in the alternative execution platforms. Our approach is based on EP, a formal executable modelling language, supplemented with OCL, and FTL, a formal language of templates. The paper illustrates the approach by generating applications from the same abstract model that run on both Googleâ Android and Apple iPhone mobile platforms. The paper contribution are: (a) it realises the MDD approach using formal languages, in particular the use of a formal language of templates and (b) it illustrates the approach by generating code for two distinct platforms. [less ▲]

Aspect-Oriented Model Development at Different Levels of Abstraction

in Modelling Foundations and Applications - 7th European Conference, ECMFA 2011 (2011)

The last decade has seen the development of diverse aspect-oriented modeling (AOM) approaches. This paper presents eight different AOM approaches that produce models at different level of abstraction. The ... [more ▼]

The last decade has seen the development of diverse aspect-oriented modeling (AOM) approaches. This paper presents eight different AOM approaches that produce models at different level of abstraction. The approaches are different with respect to the phases of the development lifecycle they target, and the support they provide for model composition and verification. The approaches are illustrated by models of the same concern from a case study to enable comparing of their expressive means. Understanding common elements and differences of approaches clarifies the role of aspect-orientation in the software development process. [less ▲]

Specifying structural properties and their constraints formally, visually and modularly using VCL

in 15th International Conference, EMMSAD 2010 (2010)

The value of visual representations in software engineering is widely recognised. This paper addresses the problem of formality and rigour in visual-based descriptions of software systems. It proposes a ... [more ▼]

The value of visual representations in software engineering is widely recognised. This paper addresses the problem of formality and rigour in visual-based descriptions of software systems. It proposes a new language, VCL, designed to be visual, formal and modular, targeting abstract specification at level of requirements, and that aims at expressing visually what is not visually expressible using mainstream visual languages, such as UML. This paper presents and illustrates VCL's approach to structural modelling based on the VCL notations of structural and constraint diagrams with a case study. VCL's contributions lie in its modularity mechanisms, and the support for two alternative styles of visual constraint modelling (one closer to set theory expressions and based on Euler diagrams, the other closer to predicate calculus and based on object graphs). [less ▲]

Modular Design by Contract Visually and Formally using VCL

in Visual Languages and Human-Centric Computing (VL/HCC) (2010)

Visual representations are widely used to describe modern-day software systems, but, in most cases, they lack rigour. This paper addresses the problems of formality, rigour and complexity in visual ... [more ▼]

Visual representations are widely used to describe modern-day software systems, but, in most cases, they lack rigour. This paper addresses the problems of formality, rigour and complexity in visual descriptions of software systems. It proposes a new language, VCL, that is designed to be visual, formal and modular, and that targets abstract specification at the level of requirements. VCL aims at expressing visually structural and behavioural properties of software systems. This paper presents design of VCL, outlining syntax and semantics of VCL notations of structural, behavioural, constraint, and contract diagrams, together with VCL's approach to behavioural modelling based on design by contract. VCL's novelty lies in the fact that contracts are modular units. [less ▲]

Visual behavioral modelling with contracts

Scientific Conference (2010)

This paper presents the Visual Contract Language (VCL). VCL is a new visual language for abstract software specification at level of requirements. It is designed to be visual, formal and modular, and aims ... [more ▼]

This paper presents the Visual Contract Language (VCL). VCL is a new visual language for abstract software specification at level of requirements. It is designed to be visual, formal and modular, and aims at expressing precisely structural and behavioural properties of software systems. VCL takes an approach to behavioral modelling based on design by contract that emphasises modularity. [less ▲]

Analysing Security requirements formally and flexibly based on suspicion

in International Journal on Advances in Security (2009), 2(4), 344-357