• Physical Therapy Korea
• /
• v.16 no.2
• /
• pp.67-76
• /
• 2009

In order to prevent upper extremity musculoskeletal disorders, effective keyboard selection is an important consideration. The aim of this study was to compare upper extremity muscle activity according to transverse plane angle changes during vertical keyboard typing. Sixteen healthy men were recruited. All subjects had a similar typing ability (rate of more than 300 keystrokes per minute) and biacromion and forearm-fingertip lengths. Four different types of keyboard (vertical keyboard with a transverse plane angle of $60^{\circ}$, $96^{\circ}$, or $120^{\circ}$, and a standard keyboard) were used with a wrist support. The test order was selected randomly for each subject. Surface electromyography (EMG) was used to measure upper extremity muscle activity during a keyboard typing task. The collected EMG data were normalized using the reference contraction and expressed as a percentage of the reference voluntary contraction (%RVC). In order to analyze the differences in EMG data, a repeated one-way analysis of variance, with a significance level of .05, was used. Bonferroni correction was used for multiple comparisons. There were significant differences in the EMG amplitude of all seven muscles (upper trapezius, middle deltoid, anterior deltoid, extensor carpi radialis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris) assessed during the keyboard typing task. The mean activity of each muscle had a tendency to increase as the transverse plane angle increased. The mean activity recorded during all vertical keyboard typing was lower than that recorded during standard keyboard typing. There was no significant difference in accuracy and error scores; however, there was a significant difference between transverse plane angles of $60^{\circ}$ and $120^{\circ}$ with regard to comfort. In conclusion, a vertical keyboard with a transverse plane angle of $60^{\circ}$ would be effective in reducing muscle activity compared with vertical keyboards with other transverse plane angles.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.8 no.3
• /
• pp.225-230
• /
• 2008

In this paper we embody a system that recognizes printed alphabet, numeral figures and symbols written on the keyboard for the recognition of English sentences. The image of the printed sentences is inputted and binarized, and the characters are separated by using histogram method that is the same as the existing character recognition method. During the abstraction of the individual characters, we classify one group that has not numerical information by the projection of the vertical center of the character. In case of another group that has the longer width than the height, we assort them by normalizing the width. The other group normalizes the height of the images. With the reverse application of the basic principle of the Japanese Puzzle to a normalized character image, the proposed system classifies and recognizes the printed numeral figures, symbols and characters, consequently we meet with good result.

• Journal of Broadcast Engineering
• /
• v.18 no.3
• /
• pp.409-415
• /
• 2013

Recently, various equipments have been developed for convenience of presentations. Presentation equipments added the keyboard and mouse functions to laser pointer and devices have become main method. However these devices have demerits of limited action and a few events. In this paper, we propose a method which increases the degrees of freedom of presentation as the control of the hand by using a depth camera. The proposed method recognizes the horizontal and vertical positions of hand pointer and the distance between hand and camera from both depth and RGB cameras, then performs a presentation event as the location and pattern that the hand touches a screen. The simulation results show that a camera is fixed on left side of the screen, and nine presentation events is correctly performed.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.4
• /
• pp.69-79
• /
• 2015

This research proposes a modified data hiding method to hide data in a slack space of an NTFS index record. The existing data hiding method is for anti-forensics, which uses traces of file names of an index entry in an index record when files are deleted in a direcotry. The proposed method in this paper modifies the existing method to make non-admittable ASCII characters for a file name applicable. By improving the existing method, problems of a file creation error due to non-admittable characters are remedied; including the non-admittable 9 characters (i. e. slash /, colon :, greater than >, less than <, question mark ?, back slash ${\backslash}$, vertical bar |, semi-colon ;, esterisk * ), reserved file names(i. e. CON, PRN, AUX, NUL, COM1~COM9, LPT1~LPT9) and two non-admittable characters for an ending character of the file name(i. e. space and dot). Two results of the two message with non-admittable ASCII characters by keyboard inputs show the applicability of the proposed method.

• Korean Journal of Cognitive Science
• /
• v.11 no.2
• /
• pp.37-51
• /
• 2000

The present study compared computer users target-selection response patterns when the targets were varied in terms of their relative location and distance from the current position of the cursor. In Experiment 1, where the mouse was used as an input device, the effects of different directions and distances of simple target(small rectangle) on target-selection response were investigated. The results of Experiment 1 can be summarized as follows: (1) Overshooting was more frequent than either undershooting or correct movement and (2) this tendency was more prominent when the targets were presented in the oblique direction or in farther location from the current cursor position. (3) Although the overshooting and undershooting were more frequent in the oblique direction, the degree of deviation was larger in horizontal and vertical direction. (4) Time spent in moving the mouse rather than that spent in planning, calibrating or clicking was found to be the most critical factor in determining total response time. In Experiment 2, effects of the font size and line-height of the target on target-selection response were compared with regard to two types of input devices(keyboard vs. mouse). The results are as follows: (1) Mouse generally yielded shorter target-selection time than keyboard. but this tendency was reversed when the targets were presented in horizontal and vertical directions. (2) In general, target-selection time was the longest in the condition of font size of 10 and line-height of 100%, and the shortest in the condition of font size of 12 and line-height of 150%. (3) When keyboard was used as the input device, target-selection time was shortest in the 150% line-height condition, whereas in the mouse condition, target-selection time tended to be increased as the line-height increased. which resulted in the significant interaction effect between input device and line-height. Finally, several issues relating to human-computer interaction were discussed based on the results of the present study.