P. John Clarkson

a species conserving genetic algorithm for multimodal function optimization

This paper introduces a new technique called species conservation for evolving parallel subpopulations. The technique is based on the concept of dividing the population into several species according to their similarity. Each of these species is built around a dominating individual called the species seed. Species seeds found in the current generation are saved (conserved) by moving them into the next generation. Our technique has proved to be very effective in finding multiple solutions of multimodal optimization problems. We demonstrate this by applying it to a set of test problems, including some problems known to be deceptive to genetic algorithms.

Graphic elicitation: using research diagrams as interview stimuli

Diagrams are effective instruments of thought and a valuable tool in conveying those thoughts to others. As such, they can be usefully employed as representations of a research domain and act as stimulus materials in interviews. This process of graphic elicitation may encourage contributions from interviewees that are difficult to obtain by other means. By representing concepts and relationships that other visual artefacts cannot depict, diagrams provide a complementary addition to conventional interview stimuli. This article discusses the application of graphic elicitation within the broader context of the diagramming process. Consideration is given to the unique characteristics of diagrams and the ways in which they are interpreted. Thus, the specific benefits that diagrams offer as interview stimuli may be understood. Following this, an example study is described in which the graphic elicitation process was employed in interviews with industrial designers. Reporting on a study in which the interviewees possessed a well-developed graphic sensibility allows a broad range of graphic elicitation’s potential benefits to be illustrated. In closing the article, a discussion is held on the range of methodological issues that must be addressed when employing diagrams in a research study.

The effects of prior experience on the use of consumer products

Many products today are laden with a host of features which, for the majority of users, remain unused and often obscure the use of the simple features of use for which the product was devised (Norman in The design of everyday things. Basic Books, 2002; Keates and Clarkson in Countering design exclusion—an introduction to inclusive design. Springer, 2004). Since the cognitive capabilities of the marketed target group are largely not affected by age-related impairment, the intellectual demands of such products are frequently high (Rabbitt in Quart J Exp Psychol 46A(3):385–434, 1993). In addition, the age and technology generation of a product user will colour their expectations of the product interface and affect the range of skills they have available (Docampo in Technology generations handling complex User Interfaces. Ph. D. thesis, 2001). This paper addresses the issue of what features of products make them easy or difficult to learn to use, for the wider population as well as the older user, and whether and in what way individual prior experience affect the learning and use of a product design. To achieve the above, the interactions of users of varying ages and capabilities with two different everyday products were recorded in detail as they performed set tasks. Retrospective verbal protocols were then analysed using a category scheme based on an analysis of types of learning and cognition errors. This data was then compared with users’ performance on individual detailed experience questionnaires and a number of tests of general and specific cognitive capabilities. The principal finding was that similarity of prior experience to the usage situation was the main determinant of performance, although there was also some evidence for a gradual, age-related capability decline. Users of all ages adopted a means-end or trial and error interaction when faced with unfamiliar elements of the interaction. There was a strong technology generation effect such that older users were reluctant or unable to complete the required tasks for a digital camera.

Matrices or node-link diagrams: which visual representation is better for visualising connectivity models?

Adjacency matrices or DSMs (design structure matrices) and node-link diagrams are both visual representations of graphs, which are a common form of data in many disciplines. DSMs are used throughout the engineering community for various applications, such as process modelling or change prediction. However, outside this community, DSMs (and other matrix-based representations of graphs) are rarely applied and node-link diagrams are very popular. This paper will examine, which representation is more suitable for visualising graphs. For this purpose, several user experiments were conducted that aimed to answer this research question in the context of product models used, for example in engineering, but the results can be generalised to other applications. These experiments identify key factors on the readability of graph visualisations and confirm work on comparisons of different representations. This study widens the scope of readability comparisons between node-link and matrix-based representations by introducing new user tasks and replacing simulated, undirected graphs with directed ones employing real-world semantics.

Mouse movements of motion-impaired users: a submovement analysis

Understanding human movement is key to improving input devices and interaction techniques. This paper presents a study of mouse movements of motion-impaired users, with an aim to gaining a better understanding of impaired movement. The cursor trajectories of six motion-impaired users and three able-bodied users are studied according to their submovement structure. Several aspects of the movement are studied, including the frequency and duration of pauses between submovements, verification times, the number of submovements, the peak speed of submovements and the accuracy of submovements in two-dimensions. Results include findings that some motion-impaired users pause more often and for longer than able-bodied users, require up to five times more submovements to complete the same task, and exhibit a correlation between error and peak submovement speed that does not exist for able-bodied users.

Towards a practical inclusive design approach

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.

Characterising user capabilities to support inclusive design evaluation

Designers require knowledge and data about users to effectively evaluate product accessibility during the early stages of design. This paper addresses this problem by setting out the sensory, cognitive and motor dimensions of user capability that are important for product interaction. The relationship between user capability and product demand is used as the underlying conceptual model for product design evaluations and for estimating the number of people potentially excluded from using a given product.

Designing inclusive futures

Designing Inclusive Futures reflects the need to explore, in a coherent way, the issues and practicalities that lie behind design that is intended to extend our active future lives. This encompasses design for inclusion in daily life at home but also extends to the workplace and for products within these contexts. For example, given trends in employment sector growth, skills requirements, labour supply and demographic change, there is a need to predict the critical areas where individual capabilities are mismatched with the physical, social and organisational demands of work. This mismatch, which can be addressed within the domain of inclusive design, is pervasively linked to real artefacts in workspaces and their intersection with the health factors that relate to ageing. This book is the result of the fourth CWUAAT workshop held in Cambridge, England in April 2008. Contributions address the following themes: Understanding Users Inclusive Design Computer Access and New Technologies Assistive Technolo gy for Working and Daily Living Environments Inclusive Environments The nature of the contributions reflect a sample of the work of leading national and international researchers in the fields of Inclusive Design, Ergonomics, Universal Access, and Assistive and Rehabilitative Technology. There have been significant contributions from researchers in architecture, social housing provision, and apparel and fashion design, reflecting the need to understand the wider social and economic context of inclusive and assistive technology design.

Investigating the applicability of user models for motion-impaired users

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.

A Holistic Categorization Framework for Literature on Engineering Change Management

Engineering changes are inevitable and might propagate within and across multiple boundaries. Their management has increasingly become relevant within the interdisciplinary field of systems engineering. A few literature categorization frameworks arising from literature reviews have been proposed to structure the research field of engineering change management. However, the literature reviews are limited in scope, and the existing categorization frameworks do not provide sufficient coverage of the research field in its broader context. This paper addresses both shortcomings. First, a new, holistic and process-oriented literature categorization framework is proposed. Second, this proposed framework is used to categorize a comprehensive list of 427 publications in engineering change management. This categorization highlights not only research areas which have gained much attention, but also those where little research has been done. Third, a citation analysis is conducted which reveals the links between the publications and indicates the most cited publications. The result of this paper will help researchers and managers to (1) navigate through the state of the art in engineering change management, (2) position their work in the overall picture of engineering change management, (3) focus on the identified research gaps and weak points, and (4) search for further research and improvement opportunities. ©2013 Wiley Periodicals, Inc. Syst Eng 16