Validation of product concepts to fulfill user needs is of great importance to develop a successful product in a market. To develop a valid concept, users could be involved at conceptual design to give feedback on the produced design solutions. Digital prototyping and quantitative feedback have received a great attention for concept validation to render design solutions and collect user feedback on the solutions respectively. In general, users have been involved at late conceptual design; (1) when designers are dealing with development of a product concept from a few design solutions (e.g. after concept screening), and (2) when refining technical specification values of the developed product concept. Involving users at early conceptual design can help to generate a space of design solutions complying better with the user needs, and select the best solutions from the space for development of a better product concept. However, such early involvement of users is considerably lacking in the existing literature. One of the major issues relating to involving users at early conceptual design is user fatigue when users give quantitative feedback on a typically big design space. To prevent fatigue, it is required to reduce the number of solutions represented to users. This reduction could cause difficulty in identifying the best target specifications and design solutions. The other issue is that users can also encounter fatigue when reviewing design solutions through interactions with digital prototypes. The fatigue negatively affects users’ feedback.
The objective of this thesis was to develop a framework for concept validation by using digital prototyping and quantitative feedback. The framework aimed to identify the best product concept by using user feedback on specification values and design solutions at early conceptual design. The framework involves users at two stages (1) before concept generation to identify the best target specifications from product design specification so as to produce better design solutions, and (2) at concept selection to identify the best solutions to develop a product concept complying better with user needs. For these two stages, two methodologies, namely specification solicitation and concept selection, were devised to deal with the large number of specification values and the big space of design solutions respectively. The methodologies utilized adaptive sampling and statistical hypothesis test. Adaptive sampling prevents user fatigue when giving feedback by effectively reducing the number of samples of specification values and solutions. The hypothesis test considers the variance of user feedback on the reduced samples as well as the mean, to resolve the difficulty in identifying the best target specifications and solutions. Specification solicitation has not been done on large number of specifications. We showed that our methodology for specification solicitation could identify the targets for a large number of specifications, while the existing methods have not gone beyond two specifications because of user fatigue. The methodology for concept selection is based on a novel approach that allows users to produce a design solution within the boundary of the space of design solutions. It was shown that the methodology outperformed a recently revealed interactive evolutionary method in terms of identifying the best solutions and preventing user fatigue. To implement the methodologies, a tool was created. The tool communicates digital prototypes to users in a new interactive way in order to help users estimate the values of specifications correctly and quickly. A novel method was developed to build hand-prototype natural interactions in virtual environment. We showed that fatigue could be effectively reduced. Besides, users could understand design solutions correctly and quickly so as to collect helpful feedback. Overall, conclusive evidence was provided that the concept validation (based on the developed framework, methodologies, and tools) can deal with a large number of specifications and solutions, and yields the product concepts that effectively fulfill user needs. To validate the proposed framework and methodologies, hand-held electronic consumer products, such as smartphones were considered for the case studies with the focus on their form, size, weight, and talktime.
|School:||National University of Singapore (Singapore)|
|School Location:||Republic of Singapore|
|Source:||DAI-B 77/06(E), Dissertation Abstracts International|
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