Research On Design And Usability Of Two-Key Stroke Virtual Keyboard Based On Chord Principle

Text input is an indispensable part of the human-computer interaction process using electronic devices.Keyboard input technology is still one of the main text input technologies.Due to the popularity of touch screen devices,virtual keyboards have been widely used in various electronic devices.Therefore,improving the performance of virtual keyboards on touch screen devices has become a hot issue for researchers.In the past,the research on virtual keyboards solved the problem of fat finger effect in the input process of virtual keyboard by scaling QWERTY keyboard,ambiguous keyboard and chord keyboard.Among them,the chord keyboard has the advantages of fast input speed,high correct rate,low number of buttons and high stability.However,in the past,the research on chord virtual keyboard lacks the research of Chinese character input.The related research on Chinese character input method is mainly divided into three categories: audio code input method,code input method(divided into stroke input method and root input method)and sound type combined input method.Among them,the stroke input method has the advantages of small number of symbols,small learning load and conforming to cognitive characteristics,and is more suitable for a chord virtual keyboard with a small number of buttons but a large learning load.This study first developed a virtual keyboard based on the chord principle and stroke input method,adding the key sequence to the key events,increasing the key combination of the two keys to five,and corresponding to the five basic strokes,and designed a new two-key chord stroke virtual keyboard.In order to explore the parameter setting and input performance of the virtual keyboard of the two-key chord stroke,this study first verified the validity of the virtual keyboard of the two-key chord stroke in the Chinese character input,and then optimized the parameter setting of the new keyboard from the perspective of the key interval,and finally passed comparing the performance and subjective evaluation of the two-key chord stroke virtual keyboard,the five-key stroke virtual keyboard and the virtual full keyboard,the input performance of the two-key chord stroke virtual keyboard was discussed.This study consists of two studies.Study 1 is a new keyboard design and its effectiveness research,including three parts: the first part is the design of the virtual keyboard of the two-key and string strokes;the second part is the experiment 1,by comparing the two-key chord stroke virtual keyboard and five-key stroke virtual,it is verified that the two-key chord stroke virtual keyboard can input Chinese characters;the third part is Experiment 2,which discussed the impact of the simultaneous key interval(60ms,80 ms,100ms)and the continuous key interval(150ms,200 ms,250ms)for the stroke input performance of two-key chord stroke virtual keyboard.Study 2 is the ecological validity study of the virtual keyboard of the two-key chord strokes,which included two parts: the first part is experiment 3,by comparing the operation changes of the two-key chord stroke virtual keyboard and the five-key stroke virtual keyboard in five days,the availability of the new keyboard was discussed;the second part is experiment 4,by comparing the operation of the two-key chord stroke virtual keyboard,the five-key stroke virtual keyboard and the virtual full keyboard in the sitting and walking state,the impact of unstable input environment on the performance of the new and old keyboard Chinese characters was discussed.Based on the above experiments,the study draws the following main conclusions:(1)The two-key chord stroke virtual keyboard can effectively input Chinese characters as same as the five-key stroke virtual keyboard,but the new keyboard before the operation time interval parameter optimization has less subjective load degree and system availability than the five-key stroke virtual keyboard;(2)When the time difference of the simultaneous key press is 80 ms and the continuous key time difference is 200 ms,the input speed and subjective load performance of the stroke input are optimal using the two-key chord stroke virtual keyboard;(3)Two-key chord stroke virtual keyboard after time interval parameter optimization is easier to learn than the five-key stroke virtual keyboard.That is,the increase in input speed of the two-key chord stroke virtual keyboard,the reduction of the subjective load,and the improvement of the usability are significantly higher than the five-key stroke virtual keyboard.Moreover,although the input speed and SUS availability of the two-key chord stroke virtual keyboard are less than the five-key stroke virtual keyboard after 5 days of practice,the input correctness rate and subjective load level are consistent with the five-key stroke virtual keyboard;(4)Two-key chord stroke virtual keyboard after time interval parameter optimization has higher stability in terms of input time.There is no significant difference in the input time of the keyboard between the sitting and walking behaviors,but the input time of the five-key stroke virtual keyboard and the virtual full keyboard in the walking state is significantly higher than that in the sitting state.This study designed a two-key stroke virtual keyboard based on chord principle,and optimized its parameter settings and discussed its input performance.In theory,this study further investigates the operational characteristics and laws of chord virtual keyboard and Chinese character input method,and provides theoretical basis for the practical application of chord virtual keyboard and Chinese character input method.In the keyboard design,a design scheme of a chord stroke virtual keyboard capable of inputting Chinese characters is provided.