kjnjdskafnke;davc

1. Supervisor
Prof. A. Bhardwaj
MNIT Jaipur
Submitted by
Dipayan Das
2013PIE5151
Pre-dissertation evaluation

2. • Pre-study:
The objectives were –
I. To prepare a complete list of descriptors that could
possibly underlie comfort and discomfort.
II. To find out whether different descriptors would underlie
comfort and discomfort or not.

3.  Steps involved in Pre-study
Collect all possible comfort and
discomfort underlying descriptors
from literature
Ask 10 experienced users to
describe their feelings when
experiencing comfort and 10
inexperienced users for discomfort
separately while using hammer
Ask them to rate on a 3 point scale
if the descriptors are related to
comfort/discomfort or not

4.  Pre study
We performed Mann – Whitney U Test to see if the
descriptors rated differently between respondents who filled in
the comfort questionnaire and discomfort questionnaire.

5.  Result of Pre-study
None of the respondents did add any new descriptors to
the list of descriptors found from literature. There were no
significant difference found between the ratings of respondents
who completed the comfort questionnaire and discomfort
questionnaire.
Therefore, it is assumed that the same descriptors underlie
comfort and discomfort in using hammer and evaluation are made
on two hammers on comfort (expected comfort at first sight and
comfort after short time use).

6. • Main Study:
The aims of the main study are to –
I. Determine the relationship between the descriptors
collected in pre-study and comfort in using hammers.
II. Classify the descriptors into factors to see if they can be
divided into meaningful groups.
III. Identify which groups predict comfort in using hammer.

7. Protocol
Rate expected comfort at
first sight on a 7 point scale
for each hammer by looking
and holding them
Ask 20 subjects who rated
comfort and discomfort
questionnaire in the pre
study to perform the task
Rate comfort questionnaire
for hammer after performing
the given task on a 7 point
scale

8. Description of the task
The subjects were asked to do hammering on 2 nails with
each hammer to get it into a wooden beam, until the head of the
nail touched the beam. The nails were driven into the wooden
beam to a very little extent before the experiment started. A rest
break of at least 5 minutes was provided after completing every
hammering-task. This procedure was repeated for all subjects.

9.  Main study
• Rating of descriptors were correlated with –
a) Expected comfort at first sight
b) Overall comfort score after use
• Multiple regression to identify which of the descriptors are
predictors of –
a) Expected comfort at first sight
b) Overall comfort score after use

10. • Principle Compound Analysis(PCA) with varimax rotation to
classify the descriptors into factors.
• Correlation between these factors and –
a) Expected comfort at first sight
b) Overall comfort score after use
• Multiple regression to see which factors predict –
a) Expected comfort at first sight
b) Overall comfort score after use

11.  Result of Main-study
From the result of correlation between the descriptors and
expected comfort & overall comfort we found that
 Expected comfort at first sight is highly correlated with 13
descriptors.
 Overall comfort after short term use is highly correlated with 7
descriptors.
 Both of them are negatively correlated with 3 descriptors.

12. • Looze, M.P. de, Kuijt‐Evers, L.F.M., Dieën, J. van, 2003.
Sitting comfort and discomfort and the relationships with
objective measures. Ergonomics, 46 (10): 985‐997.
• Editorial: Comfort and discomfort studies demonstrate the need
for a new model. 2012. Applied Ergonomics 43, 271–276
• Kuijt-Evers, L.F.M., Vink, P., de Looze, M.P., 2007. Comfort
predictors for different kinds of hand tools: differences and
similarities. Int. J. Ind. Ergon. 37, 73-84.
• Annett, J., 2002. Subjective rating scales: science or art?
Ergonomics 45, 966-987.

13. • Safety of the tool
• Easy to take along
• Good friction between handle and hand
• No inflamed skin of hand
• No numbness in fingers
• No cramped muscles
• No irritation
• Handle shape of the tool
• Styling
• No slippery handle
• Luxury tool
• No pressure on hand
• Satisfaction

14. • Easy to take along
• Low hand grip force supply
• Good friction between handle and hand
• No peak pressure on the hand
• No sweaty hands
• No sore muscles
• No pressure on hand

15. • Handle hardness of the tool
• Force exerted from the tool
• Distraction of worker from task