1. Comparing a Video Projector
and an Inter-PC Screen
Broadcasting System in a
Computer Laboratory
Takashi Yamanoue, Koichi Shimozono,
Kentaro Oda
Kagoshima University
2. Contents
1. INTRODUCTION
2. OUTLINE OF THE USABILITY TESTING
3. OUTLINE OF SOLAR-CATS
4. THE EXPERIMENT AND ITS RESULT
5. EXPERIENCES
6. RELATED WORKS
7. CONCLUDING REMARKS
3. 1. INTRODUCTION
Presentation tools in a Computer Lab.
Video projectors
Inter-PC screen broadcasting systems
…
When designing the Lab,
What kind of ?
How many
We would like to have some benchmarks of
presentation tools.
4. Experimental benchmark
A Usability testing procedure
Compared cognitive effects on users
A video projector
An inter-PC screen broadcasting system
Quantitative results
of presentation tools' cognitive effects on users'
cognition ability.
5. The usability testing
Repeat
A sample text -> Subjects, using a target tool
Subjects type
Record Typing speed and its accuracy
6. SOLAR-CATS
A computer assisted teaching tool
The text editor
User activity recorder
7. The result
The projector was better
if there was small amount of data on one screen
The screen broadcasting system was better
if there was a large amount of data on one screen.
8. 2. OUTLINE OF
THE USABILITY TESTING
A way of measuring effects of target
presentation tools
collect the results of tests on cognition of
subjects (who are supposed to be the audience or students)
after the same materials were shown
(to the subjects)
inthe same environments
using such different target tools.
9. It is not a fair comparison
to show the same materials
to the same subject using a target tool
after showing the same material to the same
subject using another target tool
because the subject can remember the
material previously shown.
10. A solution
The sample text 1 of difficulty 1
-> Subjects(1,2,…n)
usingthe target tool 1
Subjects type
Record Typing speed and its accuracy
The sample text 2 of difficulty 1
-> Subjects(1,2,…n)
usingthe target tool 2
Subjects type
Record Typing speed and its accuracy
…
11. …
The sample text k of difficulty l
-> Subjects(1,2,…n)
usingthe target tool j
Subjects type
Record Typing speed and its accuracy
The sample text k+1 of difficulty l
-> Subjects(1,2,…n)
usingthe target tool j+1
Subjects type
Record Typing speed and its accuracy
…
12. Typing speed and its accuracy
Effect
on the subject Mi
showing the k th sample text Lj,k,l
of difficulty l
Using the target tool j
E(Mi,Lj,k,l)
or
Result Ri,j,k,l (=E(Mi,Lj,k,l))
13. for(l=1; l<s; l++){
for(k=1; k<r; k++){
for(j=1; j<m; j++){
Show the material Lj,k,l using the tool Tj
to the set of subjects A={M1, …, Mn};
All of subjects test for cognition of Lj,k,l;
Collect Ri,j,k,l (=E(Mi,Lj,k,l)); }
Rest-1, a term of rest;
}
Rest-2, a term of rest;
}
14. Information conductivity
To the i th subject
From the j th target tool
Of the k th sample text of difficulty l
How fast and how precise the i-th subject
typed the Lj,k,l when j-th tool is used.
Ri,j,k,l
15. Multiplication of
Average speed of typing of the sample text
Precision (1- Error rate)
Ri,j,k,l=Avi,j,k,l(1-Aerri,j,k,l)
Letters/second
16. R*,j,*,l
Theaverage values of Ri,j,k,l in the
experiment
Where j-th target tool is used and
The materials were l-th difficulty.
17. 3. OUTLINE OF SOLAR-CATS
A WYSIWIS (What You See Is What I See)
Enables sharing real-time operation of
Applications
text editor
draw
a simple programming environment
web browser
writer’s assistant , …
All equipped with SOLAR-CATS.
18. Consists of
node systems (nodes)
a group manager.
Each node system
Applications
A main controller
A command transceiver
An event recorder/player
19. Group Manager
Teacher’s node system
TCP TCP Student’s node
Student’s node system
system
TCP
TCP TCP TCP
Student’s node Student’s node Student’s node Student’s node
system system
system system
20. Writer’s Assistant
Web Browser
Programming Environment
Text Editor
Draw
Applications
Main Controller Command Event Recorder/
Transceiver Player
Network
21.
22.
23. 4. THE EXPERIMENT AND ITS
RESULT
Image broadcasting function of SOLAR-CATS
VS.
The video projector
hung from the ceiling of the laboratory.
Brightness of the projector : 5000 lm
Size of the screen: width 2m45cm, height
1m84cm
Distance from the screen to the projector: 5m
24. Distance from the screen to the subject at the
most far side: 5m 50cm
Position of the projector from the subjects: Left
side or right side from the subjects.
Distance from the floor to the lowest side of the
screen: 92cm
Ceiling lights for the screen were turned off.
All other ceiling lights were turned on.
25. Sample texts
Power point slides of Japanese sentences
The difficulty of materials was the number of
letters on one slide.
2 kinds of difficulties (s=2)
30 letters total, 3 lines and 10 letters in one line.
The size of a letter was 72 point.
120 letters total, 6 lines and 20 letters in one
line. The size of a letter was 36 point.
6 sets of the above slides (sr=6)
37. Conductivity of projector is better
if the number of letters was smaller
Conductivity of SOLAR-CATS is better
if the number of letters was larger.
Standard distributions of the projector were
larger than that of SOLAR-CATS.
It might say that the conductivity of the
projector is affected by the subject’s position.
38. 5. RELATED WORK
Quantitative evaluation of a GUI
has been studying as a research of usability for
many years.
Survey and usability testing are used for this
evaluation[5].
Our experiment can be considered as one of
usability testing.
39. Full-dress usability testing
A usability laboratory, monitors and usability
engineers
Much money and time
40. Nielsen, J.
Easy ways of usability testing
Five subjects are enough.
If qualities of subjects is not so distributed
Our experiment
has no problem for the number of subjects
in this sense.
Automate some of observation of test and
marking the test using tools such like SOLAR-
CATS.
41. KLM (Keystroke-Level Model)
Can be used by individuals or companies
seeking ways to estimate the time it takes to
complete simple data input tasks using a
computer and mouse[2].
Our experiment uses a kind of KLM.
SOLAR-CATS was used to obtain some values of
KLM.
42. Aoki and others
A system which records and replay operations
of a Web client.
KLM using the system with an editor on a Web
page
Does not have the function which broadcast
images and operations to many clients in a
short time.
On the other hand, SOLAR-CATS has the
function.
43. Nishida and others
Collected keystroke interval data of daily usage
at computer laboratories of a university[6].
The data of computer laboratories was better
than the data of the controlled experiment.
Our experiment was a controlled experiment
this time. It is not so difficult to collect the data
of daily usage using SOLAR-CATS.
44. Tamura
An optimum letter size and an optimum space
between lines of texts
which are displayed on an electronic chalk
board for distance learning environment[7].
He has used a survey to obtain the results while
we have used usability testing. In other words,
his test is a subjective test and our test is an
objective test.
45. Kiyohara and others
Understandability of printed materials are better
than that of materials on an LCD or a CRT.
Similar to our procedure.
Used test sheets which ask yes or no answer
about contents of materials to subjects.
It requires much money or time in order to
prepare the test sheets.
Our experiment does not require test sheets.
46. 6. CONCLUDING REMARKS
A usability testing of presentation tools for
computer laboratories
Compared a video projector and inter-PC
broadcasting system
SOLAR-CATS is used
as the inter-PC broadcasting system
It is also used for recording the experiment.
47. The results were in our common knowledge.
Not new…
However, we could have Quantitative
results.
Would like to have more precise results.
48. 7. Acknowledgement
We thank our students who are subjects of
the experiment and help us to develop and
test SOLAR-CATS.
A part of this work was supported by Grant-
in-Aid for Scientific Research of Japan
Society for the Promotion of Science,
Fundamental Research(C), 17500041.