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Comparing a Video Projector and an Inter-PC Screen Broadcasting System in a Computer Laboratory

Comparing a Video Projector and an Inter-PC Screen Broadcasting System in a Computer Laboratory. Takashi Yamanoue, Koichi Shimozono, Kentaro Oda Kagoshima University. Contents. INTRODUCTION OUTLINE OF THE USABILITY TESTING OUTLINE OF SOLAR-CATS THE EXPERIMENT AND ITS RESULT EXPERIENCES

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Comparing a Video Projector and an Inter-PC Screen Broadcasting System in a Computer Laboratory

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  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 • INTRODUCTION • OUTLINE OF THE USABILITY TESTING • OUTLINE OF SOLAR-CATS • THE EXPERIMENT AND ITS RESULT • EXPERIENCES • RELATED WORKS • 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) • in the 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) • using the target tool 1 • Subjects type • Record Typing speed and its accuracy • The sample text 2 of difficulty 1-> Subjects(1,2,…n) • using the target tool 2 • Subjects type • Record Typing speed and its accuracy • … • つぎの手順をわかりやすく…

  11. … • The sample text k of difficulty l-> Subjects(1,2,…n) • using the target tool j • Subjects type • Record Typing speed and its accuracy • The sample text k+1 of difficulty l-> Subjects(1,2,…n) • using the 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,lof 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 • The average 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 Student’s nodesystem TCP Student’s nodesystem TCP TCP TCP TCP Student’s nodesystem Student’s nodesystem Student’s nodesystem Student’s nodesystem

  20. Event Recorder/Player Main Controller Command Transceiver Network Writer’s Assistant Web Browser Programming Environment Text Editor Draw Applications

  21. 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

  22. 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.

  23. 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)

  24. Examples of sample texts

  25. Target tools

  26. Recording data

  27. 82247:o-drawing fc(0).mm(180,430) • 82434:o-drawing fc(0).mxit(173,428) • … • 99219:m-tedit txtedit.txt.kty(0,0,26085) • 99219:m-tedit txtedit.txt.kty(0,1,26412)

  28. Results

  29. 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.

  30. 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.

  31. Full-dress usability testing • A usability laboratory, monitorsand usability engineers • Much money and time

  32. 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.

  33. 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.

  34. 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.

  35. 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.

  36. 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.

  37. 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.

  38. 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.

  39. The results were in our common knowledge. Not new… • However, we could have Quantitative results. • Would like to have more precise results.

  40. 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.

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