Jonathan R. A. Maier

Affordance-Based Methods for Design

In previous work, the authors have suggested that the concept of affordance, a term borrowed from the field of perceptual psychology, should be considered as more fundamental to design than other concepts such as function and behavior. This paper continues this avenue of research by presenting a generalized theory of affordances applicable to design. Then several affordance-based methods for design are presented with brief examples. Methods are introduced for designing Artifact-User Affordances, Artifact-Artifact Affordances, various kinds of graphical affordance structures, embodiment design, and reverse engineering. The affordance-based methods presented offer a very different way of thinking from what would be used in a purely functional approach. In particular, the affordance-based methods emphasize satisfaction of user demands and wishes (what the artifact should afford) while safeguarding at each step against introducing unwanted or dangerous features (what the artifact should not afford). The affordance-based methods also lend themselves to taking advantage of the multiple afffordances of various objects, to achieve naturally what is sometimes termed “functional integration”.Copyright

Comparing Function and Affordance as Bases for Design

A major objective of engineering design research has been the establishment of design science. Toward this end, there is a need to establish the fundamental concepts that should underlie the basic theories comprising a science of design. The purpose of this paper is to compare two concepts that have been proposed as bases for design—the concept of function and the concept of affordance. After exploring the history-to-date and current application of these concepts of design, they are then compared. In many respects, affordance and function complement each other, such as in describing artifacts and combining existing design methods. However, in other respects, these two concepts differ greatly, as in their theoretical underpinnings, degree of complexity, and acceptance. The issue of the degree of complexity entailed in the two concepts of affordance and function is given particular attention as it of special importance in understanding the differences between affordance and function. It is concluded that the concept of function, because it describes a simple input / output relationship, is appropriate to use in the context of the transformative type aspects of the design of artifacts. However, when the larger complex context of design is considered, including not only the artifact, but the designer and user, and all the interactions in between, the concept of affordance is appropriate because it describe complex relationships. Hence function is an appropriate basis for the design of the transformative technical character of an artifact. However affordance is an appropriate basis for the design activity in general.Copyright

The Affordance Structure Matrix: A Concept Exploration and Attention Directing Tool for Affordance Based Design

The theory of affordances has been adapted by the authors into a high-level approach to design known as affordance based design. One of the features that distinguishes the affordance based approach from function based approaches is that affordances are form dependent whereas functions are form independent. While delaying consideration of form can help maintain design freedom, considering the structure of multiple concept solutions early in the design process can preserve design freedom while allowing the designer to manipulate and refine concept structures and make prototypes early in the design process. In this paper we present a tool, the affordance-structure matrix, that aids the designer in mapping artifact structures to positive and negative affordances for the project. The affordance structure matrix can be used as an attention directing tool, focusing on the correlations within an individual concept architecture, or as a concept exploration tool, comparing the affordance-structure linkages across multiple concepts. The use of the affordance structure matrix is demonstrated using a case study examining two concept architectures for a household vacuum cleaner. The features of the affordance structure matrix are also contrasted with other existing matrix based tools for engineering design.

Understanding the Complexity of Design

The powerful concept of complexity can be applied to help us understand not only modern engineering systems, but also the design of those systems, and artifacts in general. In this chapter we attempt to establish a two-pronged theoretical framework for understanding the complexity of design. By design we mean the activity of designing artifacts in general, not any specific class of artifact. The first route to understanding the complexity of design is based on a fundamental exploration of what it means for a system to be complex. This avenue is essentially mathematical in character, and for it we rely heavily on the works of Robert Rosen, Nicholas Rashevsky, and Peter Wegner. Having discussed briefly the foundations of this approach, it is then applied to the science of design. In particular, the goal is to show that design in general is a member of the class of systems that are formally described as open and complex, and not a member of the class of systems that are formally described as closed and algorithmic. This amounts to theoretical validation for adopting a paradigm for using an open relational concept, such as affordance, as a basis for design, rather than a closed algorithmic concept such as function. This approach also suggests abstract affordance based descriptive models of design as alternatives to the current function based models of design. The second route to understanding the complexity of design lies in the study of systems that are in some obvious way complex. This approach is essentially empirical in character. Accordingly, the goal here is to show that design exhibits similar characteristics to other complex systems, in particular, as will be shown, a class of complex systems known as Complex Adaptive Systems (CAS). This constitutes more

Case Study Research Using Senior Design Projects: An Example Application

Case study research in engineering design, while not as formalized and accepted as in the social sciences, is growing in popularity because of its ability to yield significant insights into how designers interact with design problems, processes, artifacts, and each other. A wealth of evidence for use in case studies exists in the form of undergraduate senior design courses, which produce documentation related to the design of new artifacts every academic semester. The resulting documentation can be effectively mined to test hypotheses about design processes and designer behaviors. In this paper, we offer an example application of how to apply case study research to a completed senior design project in order to test a theory for how designers, users, and artifacts behave as a complex adaptive system. The evidence from the case study supports the descriptive power of the theoretical framework and supports the practical conclusion that effective communication between designers and users is particularly important and should be strengthened to foster overall project success, especially during the problem definition stage of design.

A Case Study Contrasting German Systematic Engineering Design With Affordance Based Design

In the young field of engineering design theory, various approaches to design differ in their conceptual bases, methods, and scope. These core differences make comparing design theories difficult. One strategy to overcome these differences, long used in the social sciences to test and compare theories, is the case study. In this paper we adopt a published design project, that of a computer monitor stand, and use it as a case study to compare two design theories. The design project was originally conducted using a form of German Systematic Engineering Design (GSED). We contrast those original results with what is obtainable using Affordance Based Design (ABD). Important insights into the differences between these two design theories quickly emerge. Among the differences found are the ways in which: customer needs data is interpreted and handled, product characteristics are represented, customer needs data flows into the ideation and selection processes, and bound and target data are utilized. Perhaps the most important difference shown is at what stage, and how, the product architecture is designed. In GSED, typically the product architecture arises in a bottom-up fashion from a combination of various sub-function solution principles. However, in ABD, the product architecture is the first subject of ideation and selection, as the high-level architecture determines in a top-down fashion most of the lower-level affordances that are designed subsequently. While no two design projects, design teams, or design methods are the same, it is hoped that this particular case study elucidates some of the salient differences between an established and a nascent design theory.© 2005 ASME

A taxonomy and decision support for the design and manufacture of types of product families

The realization that designing products in families can and does have significant technological and economic advantages over traditional single product design has motivated increasing interest in recent years in formal design tools and methodologies for product family design. However, currently there is no guidance for designers in the first key strategic decisions of product family design, in particular determining the type of product family to design. Hence, in this paper, first a taxonomy of different types of product families is presented which consists of seven types of product families, categorized based on number of products and time of product introduction. Next a methodology is introduced to support designers in deciding which type of product family is appropriate, based upon early knowledge about the nature of the intended product(s) and their intended market(s). From this information it follows both which manufacturing paradigm and which fundamental design strategies are appropriate for each type of product family. Finally, the proposed methodology is illustrated through a case study examining a family of whitewater kayaks.

Lightweight Engineering of Military Vehicles Through Requirements Analysis and Function Integration

The trend toward lighter-weight vehicles in the private sector has been pushed by demands to improve fuel economy, improve dynamic performance, and reduce material and transportation costs. The same demands exist and are even more acute for military vehicles. The reduction of weight across a military vehicle platform can affect hundreds of thousands of vehicles with dramatic ramifications for military budgets, logistic support, deployment time and cost, and other factors critical to national defense. In this paper we report on methods developed for requirements analysis and function integration based on a modeling framework (developed in previous work) which captures requirements, functions, working principles, components, component parameters, test measures, and tests. We also show that the problem of assigning the mass of individual components to requirements is not solvable in practice. The methods are demonstrated using a case study of the United States Department of Defense Family of Medium Tactical Vehicles (FMTV).© 2009 ASME

A comparative study of quantitative scales to populate Affordance Structure Matrices

The Affordance Structure Matrix (ASM) is a concept exploration and attention directing tool to enable designers to take advantage of the special properties of affordances, such as form dependence and polarity of positive and negative affordances. However, in an ASM, as in other popular matrix based tools, the entities being mapped (in the case of an ASM, affordances and components, respectively) are typically assumed to be of equal importance. In this paper we present a comparative study of various quantitative scales used to populate ASMs. By using these scales, we can capture the relative importance of different affordances, for example that cutting the user is more important to avoid than annoying the user with noise. Also, by using scales of increased granularity for populating the interior of an ASM, the relative strength of relationships between product components and individual components can be captured. For example, larger, heavier components have a stronger relationship with transportability than smaller, lighter components. The results of the comparison studies on the case study of a shaving razor show that a scale of negative ten through positive ten for populating the interior of the matrix is necessary to produce results which clearly rank all of the components in terms of helpful and harmful relationships. The results also show that the scale used for populating the interior of the matrix has a much stronger effect on the results than does the scale used for weighting the individual affordances. An electro-mechanical razor is used as the consumer product in the comparative study. Based on the results of the study, practical suggestions for redesigning the razor are also suggested.Copyright

On the computability of affordances as relations

Abstract One of the principal advantages of affordance-based design is that Gibsons theory of affordances is a relational theory, akin to other relational approaches such as relational biology and relational computer science. The relationships between artifacts and their designers and users are of such primary importance that only a theory that is able to deal with those relationships directly appears to be sufficient for describing the wide breadth of problems in engineering design. However, there is no precise definition for what qualifies as a relational theory. In mathematics, we do find something approaching a theory of relations, dating back at least to Charles Peirces Logic of Relatives around 1870. While rather general, Peirces ideas on the subject laid the foundation for advances in the 20th century, including the relational model of databases. This paper is a first attempt at applying the mathematics of relations to affordances, with the aim of more precisely characterizing affordances, which heretofore have been difficult to define and, lacking appropriate mathematics, nearly impossible to subject to computation. Meanwhile, the implicit computability of affordances as relations is demonstrated by examples drawn from engineering, physics, computer science, biology, and architecture.