Page 42 |
Save page Remove page | Previous | 42 of 171 | Next |
|
small (250x250 max)
medium (500x500 max)
Large (1000x1000 max)
Extra Large
large ( > 500x500)
Full Resolution
All (PDF)
|
This page
All
|
30
alternative range {1, 2, …, n} for a component selection problem with n alternatives.
The probability of each alternative of being chosen is known from Equation (3.1), then
the entropy value of the selection variable Ki can be calculated as in Equation (3.2).
2
1
( ) log
n
i ij ij
j
entropy K P P
=
= −Σ
(3.2)
Equation (3.2) explains how “certain” one design choice is in the ith time interval.
Entropy values plotted over time illustrate the changing certainty of the design process.
This plot can suggest if designers are sure of the alternative they have chosen already
or have still not made a final decision.
3.4 Results
3.4.1 Design Selection Evolution
The word occurrences of the six alternatives for the two selection problems in
intervals were collected. Figures 3.1-3.3 plot the frequencies of the three alternatives
of Problem A at intervals of 10 minutes. The dotted vertical lines mark three sessions
in which the design process took place. Figure 3.1 shows that Alternative a1 was
discussed in the first period and then again in the middle of the second period, but it
was not mentioned in the third period. Alternatives a2 and a3 were only mentioned at
the beginning of the first period (Figures 3.2 and 3.3). Comparing Figures 3.1-3.3 for
Problem A shows that mentions of Alternative a1 dominated the entire design process.
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 42 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 30 alternative range {1, 2, …, n} for a component selection problem with n alternatives. The probability of each alternative of being chosen is known from Equation (3.1), then the entropy value of the selection variable Ki can be calculated as in Equation (3.2). 2 1 ( ) log n i ij ij j entropy K P P = = −Σ (3.2) Equation (3.2) explains how “certain” one design choice is in the ith time interval. Entropy values plotted over time illustrate the changing certainty of the design process. This plot can suggest if designers are sure of the alternative they have chosen already or have still not made a final decision. 3.4 Results 3.4.1 Design Selection Evolution The word occurrences of the six alternatives for the two selection problems in intervals were collected. Figures 3.1-3.3 plot the frequencies of the three alternatives of Problem A at intervals of 10 minutes. The dotted vertical lines mark three sessions in which the design process took place. Figure 3.1 shows that Alternative a1 was discussed in the first period and then again in the middle of the second period, but it was not mentioned in the third period. Alternatives a2 and a3 were only mentioned at the beginning of the first period (Figures 3.2 and 3.3). Comparing Figures 3.1-3.3 for Problem A shows that mentions of Alternative a1 dominated the entire design process. |
