This paper addresses the general issue of software tool support for designers, helping them to structure, to communicate and to document activities of generation, evaluation and decision. Here the focus is on detailed consideration of desired and undesired behavioural relationships among elements of complex design artefacts and with end users. This is an area that has recently been under discussion by proponents and critics of Affordance Based Design methods. Our solution approach is to extend an existing graph based software tool for design rationale capture that has been in widespread use in an international aerospace company for several years. We are integrating its Issue Based Information System (IBIS) based design argumentation with hierarchical Functional Analysis Diagrams (FAD), a form of Concept Map. The resulting software is being tested by practical application on pilot projects in the company, and initial experiences have been very favourable. The new graph element types, bidirectional relationship types between graphs, and supporting navigational facilities are described. Their use is illustrated by example of an integrated hierarchical FAD and assembly geometry model of a gas turbine engine.@en

DRed is a graphical software tool for design rationale capture that, despite essentially still being a research prototype, has proved robust and useful enough gradually to achieve widespread use in an international aerospace company. The main areas of application up until now have been: (1) in the early stages of design; (2) in the root cause analysis and design of solutions to problems occurring while a product is in service. In order to lay out and navigate freely large interlinked rationales across multiple charts, DRed uses a simple bidirectional hyperlinking approach known as tunnel linking. In this paper we suggest that if it could be made easy for users to create bidirectional hyperlinks between DRed elements and selected locations in a range of external document types, then this might support the capture not just of the rationale, but of a unified, easily navigable information space covering the specification, rationale, calculations, design tasks and the emerging product definition. The objective of this research was to devise a practical way of implementing such a facility, then to explore how integrated design information spaces captured in this way might be structured, and to assess the feasibility of their capture as the design proceeds. To be successful, this will require extending the routine use of DRed from the conceptual into the embodiment design phase. Thus the case study in this paper focuses on the embodiment design of a simple mechanical transmission.@en

This work continues development and evaluation of a practical approach to a Design Research Methodology developed previously [1] and extended to practical application in [2] and concentrates on empirical techniques for research evaluation. We test a method of integrating an ethnographic approach with analytic observational techniques. The ethnographic study proved a rich source of novel insights into designers' knowledge searches during normal design activities over a 9-week period. These insights were used in conjunction with a diary study and interview data to interpret the self-report and observational data. This lead to the formation of models of the search process and the development of a number of categorisation schemes for search. A methodological analysis of a number of these schemes (1) a search tree based representation, (2) a feature commonality model, was made leading to the adoption of a scheme strongly based on the ethnographical insights rather than an abstract model. Some preliminary results from the use of this model are described and methods for verification and validation of the approach discussed.@en

This work continues development and evaluation of a practical approach to a Design Research Methodology developed previously [1] and extended to practical application in [2] and concentrates on new empirical techniques for research evaluation. The methodological challenge was to seek, without preconceptions, a research approach that enabled insight into the unobservable organisation of designers' knowledge of guideline content. A number of designers' perceptions of the similarity between items in a collection of aerospace guidelines were collected using a triad comparison. An analysis was developed that combines nonmetric multidimensional scaling analysis with hierarchical cluster analysis in order to represent the inherent structure of the perceived similarity in this data. This structure was established by examining the groupings and linear dimensions formed in the analysis outputs and relating these to guideline content. The results, which are not directly related to the standard engineering guideline organisation, may be a new indication of designers' mental models; suggesting that perceived similarity ratings and the analysis methods we have developed could be a powerful tool in eliciting designers' knowledge in general.@en