Changes to the medical device regulations within the past few years have forced medical device manufacturers to take an integrated approach to design and validation in order to ensure that their products are reliable and fit for purpose. Good design practice encourages fitness for purpose within commercial reality. This paper contains a review of the current literature that is relevant to good design practice. The results show that there is inadequate guidance regarding the integration of validation with design. Thus, there is a need for good design practice to include 'design for validation' which is aimed at designing medical devices to make them easier and more economic to validate. Research has been carried out at the Cambridge Engineering Design Centre in order to develop an approach that provides guidance in order to help designers achieve integrated design, development and validation. This will be reported in part II of this paper.

Design process planning is essential for business success. However, it is complex for all but the simplest products. There is therefore a need for eflective support for the design process planner to help them visualize and assess alternative design process strategies. This paper describes a new approach to design process planning, known as sigriposting, which has the potential to assist in the characterization, and hence planning, of a particular design process, by identifying a number of possible design routes. The success of signposting is critically dependent upon the planner’s ability CO visualize the emergent process characteristics. A number of route visualization techniques are therefore presented and discussed. The preferred approach is then developed further in an attempt to nzaximize its visualization potential.

Medical devices and their associated process equipment must be reliable and fit for purpose. In light of the recent changes to the medical device regulations, manufacturers must now take an integrated approach to design, development and validation. Good design practice encourages this integrated approach while ensuring fitness for purpose within commercial reality. A review of current literature related to good design practice carried out in Part I of this paper showed that there is inadequate guidance regarding the integration of validation with design. This paper proposes a practical approach to design for validation aimed at making devices easier and more economic to validate. The approach comes in the form of a model of design for validation that illustrates the basic relationship between design, development and validation and a series of design tactics that were formulated in order to help designers take a more proactive approach to validation during design.

This paper describes a novel implementation of the Simulated Annealing algorithm designed to explore the trade-off between multiple objectives in optimization problems. During search, the algorithm maintains and updates an archive of non-dominated solutions between each of the competing objectives. At the end of search, the final archive corresponds to a number of optimal solutions from which the designer may choose a particular configuration. A new acceptance probability formulation based on an annealing schedule with multiple temperatures (one for each objective) is proposed along with a novel restart strategy. The performance of the algorithm is demonstrated on three examples. It is concluded that the proposed algorithm offers an effective and easily implemented method for exploring the trade-off in multiobjective optimization problems.

Artificial intelligence provides powerful techniques for formalising the art of engineering problem solving: for modelling products, describing task structures, and representing problem solving expertise as inference knowledge and control knowledge. Signposting systems extend the scope of these methods beyond automatic design by using them to provide both information and guidance for decisionmaking by human designers. This paper outlines the application of AI methods according to cognitive engineering considerations, to the development of knowledge management tools for engineering design. These tools go beyond conventional knowledge management and decision support approaches by supplying both inference knowledge and strategic problem solving knowledge to the user, as well as information about the state of the design. By focusing on tasks and on the dependencies between design parameters, signposting systems support contingent and flexible organisation of activities. Such tools can support product modelling, design process planning and capturing expert design knowledge, in a form that can be used directly to guide the organisation of design activities and the performance of individual tasks. A key element of this approach is the incremental acquisition of product models, task structures and problem solving knowledge by defining variant cases.

This paper considers the differences between users with motion-impairments and able-bodied users when they interact with computers and the implications for user models. Most interface design and usability assessment practices are based on explicit or implicit models of user behaviour. This paper studies the applicability of an existing interface design user model to motion-impaired users for the relatively straightforward task of button activation. A discussion of the empirical results is provided and the paper concludes that there are significant differences between the behaviour of motion-impaired users and the accepted modelling theory.

It is known that many products are not accessible to large sections of the population. Designers instinctively design for able-bodied users and are either unaware of the needs of users with different capabilities, or do not know how to accommodate their needs into the design cycle. This aim of this paper is to present a methodological design approach for implementing inclusive design. A summary of the principal methods for designing for users with different capabilities is given along with a description of a model, the Inclusive Design Cube, that displays how the different approaches are complementary and can provide complete population coverage. A case study of the design of an information point for use in a post office, shall be used to highlight the use of the model.