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79
5.4 Experimental Study
In the large scale system design case example (Chapter 3 and 4), the team
designer’s intents of preference are not accessible, so it is impossible to study the
similarity and correlation between the transcript-extracted preferential probabilities
and the team’s real intent. In this chapter, a new experiment is conducted for
comparative study. It is a case study of a three-person design team working on two
design selection problems for coffee maker re-design. Individual design team
members were periodically asked to complete surveys of their preferences.
Preferential probabilities were then extracted from team discussion transcripts and
compared with the explicit preferences stated in surveys. An evaluating comparison is
conducted between the preference results of those two methods (Referring to Figure
1.1).
Table 5.1 summarizes the differences between the new experiment and the case
example used in the preliminary studies.
Table 5.1 Comparison of the New Experiment with the First Example
# People Level of
knowledge
Experiment
Length
Problem
Scope
Questionnaire
Experiment 1
(Space System
Re-design)
17 Experts 9 hours Large
Scale
N/A
Experiment 2
(Coffee Maker
Re-design)
3 Novices 1 hour Small
Scale
Every 10
minutes
Object Description
| Title | Extraction of preferential probabilities from early stage engineering design team discussion |
| Author | Ji, Haifeng |
| Author email | haifengj@usc.edu; haifeng.ji@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Industrial & Systems Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2008-08-19 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-10-07 |
| Advisor (committee chair) | Yang, Maria C. |
| Advisor (committee member) |
Lu, Stephen Jin, Yan |
| Abstract | Activities in the early stage of engineering design typically include the generation of design choices and selection among these design choices. A key notion in design alternative selection is that of preference in which a designer or design team assigns priorities to a set of design choices. However, preferences become more challenging to assign on both a practical and theoretical level when done by a group of individuals. Preferences may also be explicitly obtained via surveys or questionnaires in which designers are asked to rank the choices, rate choice with values, or select a "most-preferred" choice. However, these methods are typically employed at a single point of time; therefore, it may not be practical to use surveys to elicit a team’s preference change and evolution throughout the process.; This research explores the text analysis on the design discussion transcripts and presents a probabilistic approach for implicitly extracting a projection of aggregated preference-related information from the transcripts. The approach in this research graphically represents how likely a choice is to be "most preferred" by a design team over time. For evaluation purpose, two approaches are established for approximating a team's "most preferred" choice in a probabilistic way from surveys of individual team members. A design selection experiment was conducted to determine possible correlations between the preferential probabilities estimated from the team's discussion and survey ratings explicitly stated by team members. Results suggest that there are strong correlations between extracted preferential probabilities and team intents that are stated explicitly, and that the proposed methods can provide a quantitative way to understand and represent qualitative design information using a low overhead information extraction method. |
| Keyword | preferences; probabilities; concept selection; design process; design decision-making |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m1635 |
| Contributing entity | University of Southern California |
| Rights | Ji, Haifeng |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-Ji-2413 |
| Archival file | uscthesesreloadpub_Volume14/etd-Ji-2413.pdf |
Description
| Title | Page 91 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 79 5.4 Experimental Study In the large scale system design case example (Chapter 3 and 4), the team designer’s intents of preference are not accessible, so it is impossible to study the similarity and correlation between the transcript-extracted preferential probabilities and the team’s real intent. In this chapter, a new experiment is conducted for comparative study. It is a case study of a three-person design team working on two design selection problems for coffee maker re-design. Individual design team members were periodically asked to complete surveys of their preferences. Preferential probabilities were then extracted from team discussion transcripts and compared with the explicit preferences stated in surveys. An evaluating comparison is conducted between the preference results of those two methods (Referring to Figure 1.1). Table 5.1 summarizes the differences between the new experiment and the case example used in the preliminary studies. Table 5.1 Comparison of the New Experiment with the First Example # People Level of knowledge Experiment Length Problem Scope Questionnaire Experiment 1 (Space System Re-design) 17 Experts 9 hours Large Scale N/A Experiment 2 (Coffee Maker Re-design) 3 Novices 1 hour Small Scale Every 10 minutes |
