This paper describes the findings of an experiment on how different engineers understand notions of function and functional breakdown in the context of design by modification. The experiment was conducted with a homogenous group of 20 design engineers, who had all received the same education. The subjects were asked to analyze how a hydraulic pump works and summarize their understanding in a function tree. The subjects were given either the hydraulic pump itself (with part of its casing removed) or a maintenance drawing that showed a section cut of the pump. This paper shows typical outputs of the designers. It discusses the different notions of function that the subjects had and the differences in the function trees they generated. The paper focuses an eight detailed analyses to show the range of approaches the subjects took.

To complement studies on design sketching within particular phases of design processes in specific design domains, this paper analyzes descriptions of design processes given by designers from a wide variety of fields. This research forms part of a wider project on comparisons across design domains and draws attention to the many types and properties of sketches in different contexts. Further, it focuses on the multiple roles that sketching can take in idea generation, as well as in reasoning and communicating design ideas. In particular this paper examines how the different types and roles of sketches can be more or less formal and how this can lead to misunderstandings.

This study demonstrates how subtle signals taken from the early stages within a construction process can be used to diagnose potential problems within that process. For this study, the construction process is modeled as a quasi-Markov chain. A set of six different scenarios representing various common problems (e.g., small budget, complex project) is created and simulated by suitably defining the transition probabilities between nodes in the Markov chain. A Monte Carlo approach is used to parameterize a Bayesian estimator. By observing the time taken to pass the review gateway (as measured by number of hops between activity nodes), the system is able to determine with good accuracy the problem scenario that the construction process is suffering from.

Engineering risk methods and tools account for and make decisions about risk using an expected-value approach. Psychological research has shown that stakeholders and decision makers hold domain-specific risk attitudes that often vary between individuals and between enterprises. Moreover, certain companies and industries (e.g., the nuclear power industry and aerospace corporations) are very risk-averse whereas other organizations and industrial sectors (e.g., IDEO, located in the innovation and design sector) are risk tolerant and actually thrive by making risky decisions. Engineering risk methods such as failure modes and effects analysis, fault tree analysis, and others are not equipped to help stakeholders make decisions under risk-tolerant or risk-averse decision-making conditions. This article presents a novel method for translating engineering risk data from the expected-value domain into a risk appetite corrected domain using utility functions derived from the psychometric Engineering Domain-Specific Risk-Taking test results under a single-criterion decision-based design approach. The method is aspirational rather than predictive in nature through the use of a psychometric test rather than lottery methods to generate utility functions. Using this method, decisions can be made based upon risk appetite corrected risk data. We discuss development and application of the method based upon a simplified space mission design in a collaborative design-center environment. The method is shown to change risk-based decisions in certain situations where a risk-averse or risk-tolerant decision maker would likely choose differently than the expected-value approach dictates.

This paper focuses on computer-based generative methods for layout problems in architecture and urban planning with special regard for the hierarchical structuring of layout elements. The generation of layouts takes place using evolutionary algorithms, which are used to optimize the arrangement of elements in terms of overlapping within a given boundary and the topological relations between them. In this paper, the approach is extended by a data structure that facilitates the hierarchical organization of layout elements making it possible to structure and organize larger layout problems into subsets that can be solved in parallel. An important aspect for the applicability of such a system in the design process is an appropriate means of user interaction. This depends largely on the calculation speed of the system and the variety of viable solutions. These properties are evaluated for hierarchical as well as for nonhierarchical structured layout problems.

This paper explores the relationship between the quality of a sketch and how others perceive the creativity of the idea portrayed by the sketch. In this study, sketch quality is characterized through its line work, perspective, and proportions. Four different toaster ideas were each sketched by four people with different backgrounds and levels of sketching proficiency. Then, 360 reviewers ranked the toasters for idea creativity, referring to a set of four sketches: one sketch for each toaster concept. The level of sketch quality for each toaster concept was varied among one of four quality levels. Higher quality idea sketches were found to correlate with higher creativity rank (p > 0.005), and lower quality sketches correlated with a lower creativity rank (p > 0.0005). A toaster idea portrayed with the highest quality level of sketch was 2.3 times more likely to be ranked as the most creative idea within the given set of idea sketches. The results underscore the importance of how an idea is presented, and support the need for sketching instruction in engineering and design curriculum.

The goal of this paper is to reexamine assumptions about sketch-based interfaces for modeling in the context of designers' needs and practices. Research questions examine (a) the type of sketch support and (b) the timing of support. Both concepts try to determine when, what, why and how to augment design processes in a way that is useful to designers. Two experiments (one in architecture and one in product design) based on ergonomics theory are conducted and intend to question some of these assumptions. The Port Zeeland experiment examines how 20 novices perceive and copy a blurred architectural sketch, which provides clues for a sketch interpretation system. The “Tragere” experiment studies how 12 professional product designers, some of whom are “idea generators” and others “idea pursuers,” perceive, recognize, and handle a design sketch. The results take a designer's point of view in assessing the timing and value of sketch assistance in product design. The quantitative data analysis provides rich clues about when, why and how product sketches should be supported. The paper explores the strategies developed by designers to perceive and recognize graphical content and discusses the generation of three-dimensional volumes, the univocity state between sketches and three-dimensional models, and the treatment of features in freehand sketches. The paper concludes with observations on the timing and value of support, as first integrated in NEMo, a tool for early stage architectural design, and then in PEPS3, an early stage framework for product design.

Currently available computer-aided design tools provide strong support for the later stages of product development processes where the structure and shape of the design have been fixed. Support for earlier stages of product development, when both the structure and shape of the design are still fluid, demands conceptual design tools that support designers' ways of thinking and working, and enhance creativity, for example, by offering design alternatives, difficult or not, possible without the use of such tools. The potential of spatial grammars as a technology to support such design tools has been demonstrated through experimental research prototypes since the 1970s. In this paper, we provide a review of recent spatial grammar implementations, which were presented in the Design Computing and Cognition 2010 workshop on which this paper is based, in the light of requirements for conceptual design tools and identify future research directions in both research and design education.

Decision making is a significant activity within industry and although much attention has been paid to the manner in which goals impact on how decision making is executed, there has been less focus on the impact decision making resources can have. This article describes an experiment that sought to provide greater insight into the impact that resources can have on how decision making is executed. Investigated variables included the experience levels of decision makers and the quality and availability of information resources. The experiment provided insights into the variety of impacts that resources can have upon decision making, manifested through the evolution of the approaches, methods, and processes used within it. The findings illustrated that there could be an impact on the decision-making process but not on the method or approach, the method and process but not the approach, or the approach, method, and process. In addition, resources were observed to have multiple impacts, which can emerge in different timescales. Given these findings, research is suggested into the development of resource-impact models that would describe the relationships existing between the decision-making activity and resources, together with the development of techniques for reasoning using these models. This would enhance the development of systems that could offer improved levels of decision support through managing the impact of resources on decision making.

The value of sketching in engineering design has been widely documented. This paper reviews trends in recent studies on sketching in engineering design and focuses on the encouragement of sketching. The authors present three experimental studies on sketching that look at (1) sketching assignments and their motivation, (2) the impact of a sketching lesson, and (3) the use of Smartpen technology to record sketching; overall these studies address the research question: Can sketching frequency be influenced in engineering education? Influencing sketching frequency is accomplished through motivation, learning, and use of technology for sketching, respectively. Results indicate that these three elements contribute to the encouragement of sketching in engineering design.

One of the fundamental elements that determines the precision of coordinate measuring machines (CMMs) is the probe, which locates measuring points within measurement volume. In this paper genetically generated fuzzy knowledge based models of three-dimensional (3-D) probing accuracy for one- and two-stage touch trigger probes are proposed. The fuzzy models are automatically generated using a dedicated genetic algorithm developed by the authors. The algorithm uses hybrid coding, binary for the rule base and real for the database. This hybrid coding, used with a set of specialized operators of reproduction, proved to be an effective learning environment in this case. Data collection of the measured objects' coordinates was carried out using a special setup for probe testing. The authors used a novel method that applies a low-force high-resolution displacement transducer for probe error examination in 3-D space outside the CMM measurement. The genetically generated fuzzy models are constructed for both one stage (TP6) and two stage (TP200) types of probes. First, the optimal number of settings is defined using an analysis of the influence of fuzzy rules on TP6 accuracy. Then, once the number of settings is obtained, near optimal fuzzy knowledge bases are generated for both TP6 and TP200 triggering probes, followed by analysis of the finalized fuzzy rules bases for knowledge extraction about the relationships between physical setup values and error levels of the probes. The number of fuzzy sets on each premise leads to the number of physical setups needed to get satisfactory error profiles, whereas the fuzzy rules base adds to the knowledge linking the design experiment parameters to the pretravel error of CMM machines. Satisfactory fuzzy logic equivalents of the 3-D error profiles were obtained for both TP6 and TP200 with root mean squsre errors ranging from 0.00 mm to a maximum of 0.58 mm.

The natural world provides numerous cases for analogy and inspiration in engineering design. During the early stages of design, particularly during concept generation when several variants are created, biological systems can be used to inspire innovative solutions to a design problem. However, identifying and presenting the valuable knowledge from the biological domain to an engineering designer during concept generation is currently a somewhat disorganized process or requires extensive knowledge of the biological system. To circumvent the knowledge requirement problem, we developed a computational approach for discovering biological inspiration during the early stages of design that integrates with established function-based design methods. This research defines and formalizes the information identification and knowledge transfer processes that enable systematic development of biologically inspired designs. The framework that supports our computational design approach is provided along with an example of a smart flooring device to demonstrate the approach. Biologically inspired conceptual designs are presented and validated through a literature search and comparison to existing products.