Research On Touch Gesture Interaction In Different Holding Postures For Smart Mobile Devices

With the advances of hardware,smart mobile devices' computing performance is becoming more and more powerful,leading to increasingly richer functions.Hence,such devices have played an important role in peoples' daily lives.Smart mobile devices can support multi holding postures due to its mobility.Touch gesture interaction is a common way to interact with smart mobile devices,and such topic has attracted much research attention.This thesis investigated touch gesture interaction on mobile devices with the focus on three common holding postures when interacting with smart mobile devices.This thesis includes the following aspects:Firstly,for back-of-device gesture interaction with one-handed holding posture,a comparative study was run to investigate one-handed gesture input on the front and back of the mobile device.Results show that the performance of the index finger gesture input on the back is generally worse than that of the thumb gesture input on the front,the thumb is faster and more accurate than the index finger.They are similar in local shape features such as indicative angle difference and distance between start point and end point of closed gestures,while for gesture size ratio,the index finger perform better.In general,back-of-device gestures for index finger should not be too complicated,and required smaller input area.Experimental results provide guidance on back-of-device gesture interaction design.Secondly,for two-handed gesture interaction in the two-hand holding posture,a study was conducted to investigate differences and similarities between dominant thumb(DT)and non-dominant thumb(NT)for pointing and gesturing tasks with bimanual tablet griping interaction.Results show that in pointing experiment,DT had shorter average pointing time than NT,and the optimal target size that DT required is smaller than NT(7.7mm and 9.4mm respectively).But they are alike in pointing accuracy and can be modeled by Fitts' law.In gesturing experiment,results show that DT and NT have significant difference in gesture features such as articulation time,gesture size ratio and indicative angle difference,while similar in features like aperture,axial symmetry and shape distance.These findings provide design implications for bimanual gesture interaction.Thirdly,a study was carried out to investigate effects of holding postures on user-defined touch gestures for tablet interaction.Three commonly used holding postures(i.e.one-handed palm,onehanded arm and two-handed palm)were considered,and target position and moving distance were also taken into account.In total 1,293 user-defined gestures were collected for 30 commonly used commands.Results show that for some referents like open and pan,holding postures have no effect on the user-defined gesture design.But for some referents like move a lot,holding postures have significant influence.Users' prior interaction experience also have significant impact on user-defined gesture design.The results provide implications for touch gesture interaction.This thesis studied touch gesture interaction in different holding postures for smart mobile devices.Research results could enrich the topic of touch gesture interaction on smart mobile devices,and could provide references for touch gesture design.