This Special Issue is in an exceptional format. Starting with an
invited Keynote by Rob Woodbury and Andrew Burrow, the rest of the issue
is taken up by invited papers that are responses to Woodbury and
Burrow's paper, written by selected authorities on design. A final
short section is devoted to Woodbury and Burrow's reactions to the
responses.
Rob Woodbury and Andrew Burrow set the stage in their paper
“Whither design space?” The exploration of design spaces is a
long-standing focus in computational design research. Design space
exploration is the idea that computers can be used to help designers by
representing many designs, organizing them in a network structure that
forms the space, and by assisting designers to explore this space: that
is, to make new designs and to move among previously discovered designs in
the network.
Three main areas of research into design space exploration can be
distinguished. The first area of research concerns accounts of designer
action and aims to reproduce and extend the behavior of designers. It is
based on the premise that exploration is a good model for designer action.
The second area of research aims to develop strategies and tools that
amplify designer action in exploration. The third area of research
concerns the discovery and development of computational structures to
support exploration, including representations of the design space
itself.
Woodbury and Burrow specifically focus on computational access to the
design space and the implications of having a design space representation
in reference to the premise that exploration is a good model for designer
action. Possible structures for a design space are conditioned by models
of exploration behavior, by choices of strategies for amplifying designer
action, and by the limits imposed by both computation itself and our
knowledge of it. Formalisms for design space exploration must
simultaneously accord with designer action, implement a useful
amplification strategy, and be both formalizable and computationally
tractable.
Woodbury and Burrow raise, and answer, a number of questions, for
example, what defines a good representation? Are design rules or, instead,
design operators, the appropriate encoding mechanism for design moves in
the design space? What is the role of the explicit design space, that is,
the part of the design space the designer has previously visited, and what
is the role of trajectories of design moves in design exploration? These
questions, and others, form the basis for a discussion that can serve as a
stepping stone for future research into design spaces.
Ömer Akın distinguishes the paper by Woodbury and Burrow
from previous efforts at exploring and studying the design space as taking
an axe to an old growth trunk, compared to whittling away at the bark.
Even then, the trunk remains massive and vast. In “The Whittled
Design Space,” Akın examines Woodbury and Burrow's paper
according to four criteria: completeness, discrimination, alternative
approaches, and combining exploration in different problem domains. With
respect to the latter criterion, the author suggests the
structure–function–behavior model as an analogy for the
central parameters of the search space paradigm. He concludes with a
number of questions both for this Special Issue and for future
research.
Ulrich Flemming indicates having no fundamental difficulties with
Woodbury and Burrow's paper, apart from some quibbles here and there.
In “Yes, and by the Way … ,” Flemming picks up on the
issue raised by Woodbury and Burrow of taking the specific domain
representation too seriously, in particular, confusing the knowledge level
with the underlying symbol level. He suggests that
“mixed-initiative” design support systems need a symbol level
consisting of a distinct task layer on top of the computational layer
where the computational power of the system rests. The author also
expresses unease with some details of Woodbury and Burrow's paper,
including their criticism of standard rule-based accounts of design space
exploration.
Ramesh Krishnamurti compliments Woodbury and Burrow for exploring a
new kind of navigation. In “Explicit Design Space?”
Krishnamurti examines the need for an explicit representation of the
design space, along with an explicit representation of a particular search
strategy, as proposed by Woodbury and Burrow. He does so by exploring
issues with respect to design search and representation in general, in
relation to specific issues raised by Woodbury and Burrow. The need for
exogenous properties in design representations, the role subsumption plays
in information restructuring, and the notion of replay, are some of the
issues that are reviewed.
Gabriela Goldschmidt opts in “Quo Vadis, Design Space
Explorer?” to bring to the discussion some additional concerns
rather than respond directly to points raised in the paper. Goldschmidt
broadens the notion of exploration and bases it on a more
cognition-oriented footing, concluding that the design space should be
conceived as a multilevel and multifaceted construct that supports on the
spot experimentation and provides essential feedback also concerning the
process of designing.
Pieter van Langen and Frances Brazier argue in “Design Space
Exploration Revisited” that design space exploration involves
exploration in three related spaces. Besides the space of partial
descriptions of design artifacts that Woodbury and Burrow describe, these
are the space of design requirements and the space of design process
objectives. Van Langen and Brazier propose to make the information
compiled in the paths of exploration across these three spaces explicit,
thereby increasing options for accessibility.
Gerald Penn offers in “Design Space and Typed Feature
Logic” some insights into the logic of typed feature structures,
including some of its weaknesses, recounting how Woodbury, Burrow, and
colleagues have adapted it to design space navigation.
Sambit Datta, in “Modeling Dialogue With Mixed Initiative in
Design Space Exploration,” addresses human–computer
interaction over typed feature structures in the context of design space
exploration and presents a visual notation for representing dialogue
between designer and computational formalism.
Rob Woodbury and Andrew Burrow get the last word in this issue. In
“A Typology of Design Space Explorers,” they map the various
responses, and their own work, according to two axes: the spectrum of
strengths and needs that stretches from the machine to the human, and the
time scale of events in design. They argue that the resulting landscape,
reflecting on apparent differences of opinion, is in fact the result of
differences in emphases, rather than actual disagreements.
I believe that this issue will be a valuable source for designers and
researchers, for at least three reasons. First, it serves as an important
account of research into design space exploration that can serve as a
reference for this subject in literature. Second, it raises fascinating
issues related to design space exploration that can be the subject of
future research and investigations. Third, it provides for a unique
account of a lively discussion between a number of authorities on
design.
I am indebted to Tim Smithers, who came up with the idea of this
Special Issue, as I recall, in a conversation with Rob Woodbury during the
Design Computing and Cognition Conference in Boston in July 2004. It is an
honor to bring to fruition this special experiment. I also thank all the
authors for their enthusiastic participation in this Special Issue.
Finally, I express thanks to Dave Brown, Editor in Chief of
AIEDAM, for his advice and support during the process of editing
this Special Issue.
