Hans Peter Lomholt Bruun

An Approach to the Static Semantics of VDM-SL

The work presented here concerns abstract specification of type checking for a specification language VDM-SL of the Vienna Development Method. Where previous work has focussed on rejection of “obviously” ill-typed specifications we do, in addition, consider acceptance of “obviously” well-typed expressions.

Interface diagram: Design tool for supporting the development of modularity in complex product systems

For products with a myriad of systems, groups of specialised engineers develop entire technical sub-systems, and great effort is needed to integrate these systems for fulfilling the product’s intended properties describing its purposeful behaviour. This way of developing products gets even more complex when using a mass customisation strategy because standard designs (reusable modules) have to be designed to fit a range of products. This product development set-up requires that engineers working in different technical domains collaborate and are able to share information in a unified way. This article presents a visual design tool –the Interface diagram– which aims to support the engineering process of developing modularity in complex product systems. The tool is a model of a product system representing the arrangement of its elements and their interfaces. The tool has similar characteristics to a high-level product architecture model, aiming at supporting integration of technical sub-systems by documenting interfaces and interactions among components from different functional sub-systems and among different physical modules. One of the objectives for using the design tool is to support the activity of decomposing a product system into modules consisting of components developed by different engineering teams. The usefulness of the Interface diagram has been tested in an industrial development project showing positive results of shortening the lead time and minimising rework. Moreover, the Interface diagram has been used in interplay with a broader Product Lifecycle Management system. This allows the product structures from the Interface diagram to be enriched with detailed product documentation like computer-aided design, requirements, view models, design specifications and interface descriptions.

PLM system support for modular product development

Develop and evaluate modular concepts for complex products.Clear responsibility for interfaces.All engineering teams have access to the same single source of information.Visualisation of multiple views on products.Automated reporting on design progress and cost. A modular design strategy both enables, but also demands, parallelism in design activities and collaboration between a diversity of disciplines in companies, which often involves supporting computer-based tools for enhancing interaction, design management, and communication. Product data management (PDM) and product lifecycle management (PLM) systems offer support by automating and managing some of the operational complexity of modular design activities. PLM system tools are used for handling a variety of product definitions, to manage workflow of development activities, and to measure relational properties such as cost and performance. Companies often use a PLM tool for management of CAD files, documents, and drawings, but they do not take advantage of the full potential of the PLM system to support the development activities of modular product designs. The key result of this paper is the description of an empirical tested approach using a visual product architecture representation in combination with a PLM system to support the development of a product family of products. The results from the study encompass new PLM capabilities for handling multiple product structures, visualising multiple architectural views on products, controlling interfaces, and quantifying and communicating the status and progress of product-related resources.

Visual Product Architecture Modelling for Structuring Data in a PLM System

The goal of this paper is to determine the role of a product architecture model to support communication and to form the basis for developing and maintaining information of product structures in a PLM system. This paper contains descriptions of a modelling tool to represent a product architecture in a company to support the development of a family of products, as well as the reasons leading to the use of the specific model and its terminology. The fundamental idea for using the architecture model is that an improved understanding of the whole product system, will lead to better decision making. Moreover, it is discussed how the sometimes intangible elements and phenomena within an architecture model can be visually modeled in order to form the basis for a data model in a PLM system.

Domain Theory, Its Models and Concepts

Domain Theory is a systems approach for the analysis and synthesis of products. Its basic idea is to view a product as systems of activities, organs and parts and to define structure, elements, behaviour and function in these domains. The theory is a basis for a long line of research contributions and industrial applications especially for the DFX areas (not reported here) and for product modelling. The theory therefore contains a rich ontology of interrelated concepts. The Domain Theory is not aiming to create normative methods but the creation of a collection of concepts related to design phenomena, which can support design work and to form elements of designers’ mindsets and thereby their practice. The theory is a model-based theory, which means it is composed of concepts and models, which explains certain design phenomena. Many similar theories are described in the literature with differences in the set of concepts but assumingly all valid. The Domain Theory cannot be falsified or proven; but its value may be seen spanning from its range and productivity as described in the article.

On Type Checking in VDM and Related Consistency Issues

The variants of specification languages used with the Vienna Development Method (VDM) offer a rather expressive notion of types. Higher order function types, recursively defined types, and a notion of union types which does not require injection and projection are all included, not to mention subtypes characterized by arbitrary predicates.

Distributive lattice-structured ontologies

In this paper we describe a language and method for deriving ontologies and ordering databases. The ontological structures arrived at are distributive lattices with attribution operations that preserve ∨, ∧ and ⊥. The preservation of ∧ allows the attributes to model the natural join operation in databases. We start by introducing ontological frameworks and knowledge bases and define the notion of a solution of a knowledge base. The import of this definition is that it specifies under what condition all information relevant to the domain of interest is present and it allows us to prove that a knowledge base always has a smallest, or terminal, solution. Though universal or initial solutions almost always are infinite in this setting with attributes, the terminal solution is finite in many cases. We describe a method for computing terminal solutions and give some conditions for termination and non-termination. The approach is predominantly coalgebraic, using Priestley duality, and calculations are made in the terminal coalgebra for the category of bounded distributive lattices with attribution operations.

The VDM-SL Editor and Consistency Checker

As a part of the standardization of the VDM specification language (VDM-SL), the static semantics of VDM-SL is being defined. During this de~nltion it has been found valuable to develop an editor and consistency checker for VDM-SL since the static semantics of VDM-SL is defined using VDM-SL itself. The aim of the tool is firstly to support the editing of the definition. Secondly, we want to be able to validate the consistency of the definition. The editor is a so-called syntax directed editor. The attention is put on the abstract syntax tree and editing operations are performed on this tree. For this reason, the user can focus on what to specify and abstract from other aspects such as syntactical details and typographical layout details. The editor does not only support editing of VDM-SL formulae but includes also facilities for merging VDM-SL formulae with regular text, sectioning, annotating specifications, generation and maintenance of symbolic references. Finally, it is possible to influence the layout (e.g. line breaking and indentation) of a specification, During editing, the consistency checker operates in accordance with the static semantics [1]. Typical inconsistencies which may be detected are type errors and erroneous use of identifiers. Total consistency of VDM-SL specifications is, however, generally tmdecidable [2]. In accordance with the static semantics, the consistency checker generates proof obligations when it cannot verify consistency automatically.