학위논문 (석사)-- 서울대학교 대학원 : 산업공학과, 2014. 2. 윤명환.To design handheld devices, physical comfort is one of the most crucial requirements. Recently, curved handheld touchscreens were released for enhancing comfort, but the effect has not been proved yet. There are two ergonomic factors, anthropometric and physiological factors, respecting comfort. This means the design should consider variation of hands in size and shape as well as muscle utilization. Through statistical analysis, it has been showed that the Korean population has large variability in both size and shape. Also, it has been observed that 1/3 of user population of smartphone operate the device unimanully by a previous research.
This study aimed to verify the effect of anthropometric factors of hands and curvature on comfort when using handheld touchscreen devices. Comfort level was measured employing both the subjective rating and EMG methods. Three mock-ups of handheld touchscreen device with different curvatures were utilized. One was flat device and the others had curvatures of 400R and 100R. An experiment was conducted on tapping, typing and dragging tasks. The results indicated that curvature of the handheld touchscreen devices did not affect muscle activities, but subjective comfort level. Moreover, size and shape of hand were found to affect muscle activities and comfort level when using the handheld touchscreen devices. Target location and moving direction of thumb were also factors that significantly affected muscle activities. Overall, this study suggests that user interface design may be more important than curvature of handheld touchscreen determining comfort of touch screen use.TABLE OF CONTENTS I
LIST OF FIGURES IV
LIST OF TABLES VI
CHAPTER 1. INTRODUCTION 1
1.1 Research Background 1
1.2 Objective and Scope of the Study 3
1.3 Definition and Terminology 4
CHAPTER 2. LITERATURE REVIEW 5
2.1 Comfort 5
2.1.1 The role of comfort in usability 5
2.1.2 Comfort and discomfort - Definition and dimensions 7
2.1.3 Measurement of comfort and discomfort 10
2.1.4 Comfort and ergonimics 11
2.2 Hand 14
2.2.1 Anthropometry of the hand 14
2.2.2 Hand and comfort 16
2.3 Researches Done on Smartphone 18
2.4 Limits of Previous Studies 19
CHAPTER 3. RESEARCH METHODOLOGY 21
3.1 Hypothesis 21
3.2 Statistical Analysis on Hand 22
3.3 Apparatus 23
3.4 Subjects 25
3.5 Experimental Design 25
3.5.1 Tasks 25
3.5.2 Measurements 29
3.5.3 Procedure 33
3.6 Data Analysis 35
CHAPTER 4. RESULTS 36
4.1 Group classification by the size and the shape of hand 36
4.1.1 Group classification by actual size of hand 36
4.1.2 Group classification by shape of hand 38
4.2 General statistical results of muscle activity and comfort 40
4.3 The Effects of Curvature on Muscle Activity and Comfort 42
4.3.1 The effect of curvature on muscle activity 43
4.3.2 The effect of curvature on comfort level 44
4.4 The Effects of Size of The Hand on Muscle Activity and Comfort 46
4.4.1 The effect of the hand size on muscle activity 46
4.4.2 The effect of the hand size on comfort 48
4.4.3 The compound effect of curvature and the hand size on comfort 48
4.5 The effect of the hand shape on muscle activity and comfort 49
4.5.1 The effect of the hand shape on muscle activity 49
4.5.2 The effect of the hand shape on comfort 51
4.5.3 The compound effect of curvature and the hand shape on comfort 52
4.6 Muscle activities of levels for each task 53
4.6.1 Tapping task 53
4.6.2 Dragging task 53
CHAPTER 5. CONCLUSION AND DISCUSSION 57
REFERENCE 63
국문 초록 77
APPENDICES 78
Appendix A. Hand Dimension Description 78
Appendix B. EMG System Specification 84
Appendix C. Experimental Sheet 85
Appendix D. Descriptive Statistics for Hand Dimensions of Participants 86
Appendix E. The Result of ANOVA Test 87
Appendix F. Curve Fitting Model Summary and Parameter Estimates 97Maste
