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					A HCI Keyboard Layout Design for Blind People Kitsana Kladyoo Informatics Research Laboratory University of the Thai Chamber of Commerce 126/1 Vibhavadi Rangsit Rd., Bangkok, Thailand E-mail: kitsanakladyoo@hotmail.com Supachate Innet Computer Engineering Department University of the Thai Chamber of Commerce 126/1 Vibhavadi Rangsit Rd., Bangkok, Thailand E-mail: supachate_inn@utcc.ac.th

ABSTRACT
Presently, computers have become a part of everybody daily life, including disables such as blind people. A keyboard is a main input equipment of computers. However, these keyboards are not yet suitable for blind people, especially for the Thai alphabet system. This paper proposes a new layout design of computer keyboard for blind people. The research results show that Braille character code is very attractive to be used for designing the layout. Many mechanisms for arrangement the keys or buttons are ● investigated and the results shows that to type Thai Braille character code, the keyboard layout requires add/drop cells buttons in ○ addition to the normal buttons representing number 1 to 6 of the Braille character code. Moreover, the results suggest that such ○ buttons must be in order of 5 3 1 2 4 and 6 rather than 1 2 3 4 5 and 6 1 which 1 has been used in many keyboard currently available on the market. 2 2

1. INTRODUCTION

3 3 Presently, computers have become a part of everybody daily life, including disables such as blind people. Data from National Characters 1 Statistical Office has shown that in 2001 are as large as 123,157 blind people in Thailand [1]. Many of these people who have ● computer skill can use a computer to work. However, they find E 9.7 ○1 themselves very hard to work with a computer as it necessary to ○ T choose a program from the menu, to type a word document or to use A 6.7 a 1 2 mouse to click on the menu bar. A keyboard is a main input O 6 equipment of computers. Many computer keyboards have been developed for blinds, including Braille keyboard, less button 2 3 I keyboard, etc. However, there are not yet suitable for blind people, especially for the Thai alphabet system. This paper proposes a 5.8 new layout design of computer keyboard for blind people. This keyboard enables users to type in bothNEnglish and Thai by using ●3 Braille characters code, and actually supports all other languages that Braille characters are available. The result shows that Braille S ○ character code is very attractive to be used for designing the layout. Characters R 5 2 ○1 E H 9.7 3.7 1 T L 3.3 7.2 2 6.7 D 3.3 A O C 6 2.7 3 Figure 1: Braille characters arrangement. U 2.2 5.9 I M 2.2 Characters N 1 5.8 2 P 1.8 5.7 S E 9.7 alphabet a alphabet b alphabet c R F 5 1.8 T 7.2 5 G 1.6 3.7 A H 6.7 3.7 L W 3.3 3.3 O 6 Figure 2: Examples of writing alphabet a, b, and c by using IBraille characters. B D 3.3 1.5 5.9 C Y 2.7 1.2 N 5.8 U . 2.2 S 5.7 , R M 5 2.2 5 P V 1.8 0.8 H 3.7 3.7 1.8 K 0.6 F 1.8 L 3.3 3.3 1.8 ‘ 16 D G 3.3 1.6 W 1.5 C 2.7

Figure 3: Braille characters arrangement after adding 3 cells

2. INTRODUCTION TO BRAILLE CHARACTERS
A Braille character is constructed of six dots arranged in three rows 2 columns so called a cell, and each dot is positioned as shown in Figure 1. From this arrangement, it can be seen that, there are different combinations; hence, 64 different symbols can be represented, which is enough for English alphabets and symbols. For Thai alphabets, vowels, and symbols, there are more than 106 different characters, which requires at least two cells to represent all the characters. In fact, some Thai Braille codes use three cells to represent, i.e.,

“ฤา” or “ฦา”. This problem can be solved by adding number of cells as shown in Figure 3.

3. EVOLUTION OF KEYBOARD FOR BLIND PEOPLE
Development of computer keyboards can be in two main directions: normal button keyboards, and virtual keyboards. Both types of keyboard have been developed by concerning about fast and easy to type. In addition, button keyboards or normal computer keyboard are now developed by concerning about users’ healthy. While, virtual keyboards or on-screen keyboards are developed for small size computer such as PDAs or smart-phone handsets, and for touch screen computers where there is no space required. For blind people, virtual keyboards are useless, as they cannot see the screen, while Braille characters involves design of keyboard for them. A. Stickering [2] Evolution of keyboard for blind people starts with putting stickers of Braille characters on the each button of normal, e.g., QWERTY keyboard. This type of keyboard is; therefore, suitable to blind people who are start using computer for typing documents. For those blind people who type at high speed, it is not recommended as it is very difficult to check back whether the typed characters are corrected or not. B. Portset BrailleKey [3] Portset BrailleKey keyboard is designed to have only nine buttons, i.e., button number 1 to 6, a backspace, a spacebar, and an enter button. The buttons are lined in ascendant order from left to right, i.e., using easy-to-remember mechanism. Additionally, typing error will be reduced, as users do not have to move fingers out of the key. To type a character, users must press Braille character code, e.g., typing “a” by pressing button 1. However, this keyboard does not support all Thai characters and others languages that need more than 64 characters as it cannot increase number of cells. Figure 4 shows Portset BrailleKey keyboard. C. Portset BrailleKey G2 [4] Portset BrailleKey G2 is developed from the Portset BrailleKey. There are six more buttons adding to the first generation: ctrl, alt, and up, down, left, and right arrows. Nevertheless, it is still unable to use with other languages. D. BRAILLEX EL Braille Assistant QWERTY Keyboard [5] This keyboard is designed to have similar shape as QWERTY or normal keyboard, but smaller. It includes two special functions which are Braille display function and sound function so that users can re-check if the typing is corrected or not. Figure 5 illustrates BRAILLEX EL Braille Assistant QWERTY Keyboard. Although, this keyboard supports many different languages, users take time to learn typing characters especially new users. E. BRAILLEX EL Braille Assistant (ELBA) [6] This keyboard is a new generation of the above keyboard. Numbers of button are reduced to 11 buttons similar to Braille characters code for typing a character. F. Braille Note BT 32 [7] The Braille Note BT 32 redesigns the button to be more suitable for the position of hands. It also provides Braille display function and sound function so that users can re-check if the typing is corrected or not. This type of keyboard has the same disadvantage of those keyboards above. That is it does not support language that has more than 64 characters. Moreover, the results from the display may be misreading as will be discussed in the next section. Figure 8 shows the picture of Braille Note BT 32. The evolution of keyboard layout is shown in Figure 9. Figure 4: Portset BrailleKey keyboard Figure 5: Portset BrailleKey G2 keyboard

Figure 6: BRAILLEX EL Braille Assistant QWERTY Keyboard Figure 7: BRAILLEX EL Braille Assistant (ELBA)

Figure 8: Braille Note BT 32

code

cells

must

be

added.

Figure 10: Evolution of keyboard layout

4. DESIGNING TECHNIQUE FOR THAI BRAILLE CHARACTERS
Employing Braille character code for typing a document seems to be the most appropriate mechanism to help blind people typing an electronic document. This is because it needs only six buttons to represent a character and most of blind people are already know Braille character code so they do not need to remember position of characters. Therefore, in this paper, this mechanism is employed and the keyboard layout is designed on Human Computer Interaction (HCI)

Otherwise, some misreading might be occurred. Figure 11 shows some misreading that might be happened when typing a Thai word i.e., a computer may write “สังขธอง” instead of “สังข ”. From this concern, the keyboard should provide add/drop cell functions to tell the computer that this is a two-cell or a three-cell character. A sound function maybe includes letting users know what the computer read from their typing. Figure 12 illustrates the proposed keyboard layout that provides add/drop cell functions. Figure 10: Some mistakes that might be happened when typing two Braille character code in continuous

Figure 12: Proposed keyboard layout

basis. As discussed early, six buttons provide 64 combinations of characters which are not enough for Thai alphabets, vowels and symbols. To type all Thai alphabets, vowels, and symbols, one or two Braille

Figure 13: Letter frequency in the news corpus

5. A STUDY OF MECHANISM FOR SELECTING BUTTON’S LOCATON

respectively. From the best of knowledge, there is no research on keyboard layout design for blind people that study for appropriate mechanisms for locating keyboard buttons. Most of the studies, especially in business sectors, use either easy-to-remember or frequency of use mechanisms to locate the button number 1 to 6 on the keyboard. In fact, there are several mechanisms to design keyboard layout. This includes design with easy-to-use mechanism, frequency of use mechanism, hands skill, fingers skill mechanism, and there combinations. For easy-to-remember mechanisms, the buttons are located on the place that is easy to remember, e.g., in sequence. While for frequency of use mechanism, the buttons are arranged by the frequency that the buttons are pressed. [8] studied the frequency of use for each English character, which is referred by many researchers, and the result is showed in Figure 13. To determine the frequency of use for each button in typing Braille characters, the frequency of use for each character is tabling in terms of the button that represented. For example, in Braille character code (both UK and US) the character E is represented with point 1 and 5, i.e., button 1 and button 5. Additionally, the frequency of use for character E is 9.7% as shown in Figure 13. Hence the button 1 and button 5 has frequency of use equal 9.7%. Table 1 and Table 2 show the frequency of use for each button in typing Braille characters for UK Braille character code and US Braille character code The accumulative frequency of use for each button can be determined from Equation 1:

w h e r e : A c c

u m ul at iv e fr e q u

e n c y of us e fo r b

ut to n

(1)

b :

Percentage of frequency of use for i character i : Total number of characters

F r o m E q u a ti o n 1 a n d d a t a f r o m T a b l e 1 a n d T a b l e 2 , it c a n b

e se e n th at b ot h U ni te d K in g d o m B ra ill e c h ar ac te r c o d e a n d U ni te d St at es B ra ill e

c h ar ac te r c o d e pr o vi d e si m il ar re su lt s as sh o w n in T a bl e 3. T h e re su lt sh o w s th at b

ut to n 2 is th e m

os t fr e q u e n c y us e b ut to n w it h a hi g h p er ce nt a g e of 5 6. 9 ( U K

) or 54.6 (US). Button 1 comes in the second and then button 3, 4, 5 and 6 respectively. All button have more than 35 percentage excepted button 6 where it has been use approximately for not over to 9 percentage. Table 3 shows the accumulative frequency of use For hands skill mechanism, the buttons are positioned on the basis that people are either right-handers or left-handers. Thus, for right-handers the buttons are located first with right-hand then left-hand, and alternately for left-handers. Finger skill mechanism is based on the fact that people are strong with using point finger to type more than middle and ring finger. Therefore, the buttons are located first from point finger, then, middle finger and last ring finger.

Table 1: Character frequency of use from United Kingdom computer Braille (in percentage)

1 2 3 T a b l e 2 : C h a r a c t e r f r e q u e n c y o f u s e f r o m U n it e d S t a t e s c o m p u t e r B r a il ● ○ ○ 1 2 3 Characters E T A O I N S R H L D C U M P F G W B Y . , V K ‘ 1 J 0 “ ~ 1 9.7 6.7 6 5.9 5.8 5 3.7 3.3 3.3 2.7 2.2 2.2 1.8 1.8 1.6 1.5 1.2 5.7 5 3.7 3.3 5.8 5.7 5 3.3 3.3 2.7 2.2 2.2 1.8 2.2 1.8 1.8 1.6 1.5 1.2 2 7.2 3 7.2 6 5.9 5.8 5.7 ○ ○ ○ 4 5 6 ○ ○ ○ ○ ○ ○ 4 7.2 7 8 9

○ 4 ○ 5 ○ 6 ● ● ○ ○ ○ ○ ○ ○ ○ 1 0 1 1 1 2

○ ○ ○ ● ○ ○ ○ ○ ○ 5 9.7 7.2 6 5.8 5 3.7 3.3 2.2 1 3 1 4 1 5 ● ○ ○ 1 ○ 6 ○ 1 7 ○ 1 8

○ ○ ○ 6

1.8 1.8 16 1.5 1.5 1.1 1 0.8

1.6 1.5 1.2 1.1

1.5 1.2 1.1 0.8

1.2

0.8 0.6

0.8 0.6 0.4 0.3 0.2 0.2 0.2 0.2 1 9.7 6.7 6 5.9 5.8 5 3.7 3.3 3.3 2.7 2.2 2.2 5.7 5 3.7 3.3 5.8 5.7 5 3.3 3.3 2.7 2.2 2.2 2.2 3.3 2 7.2 3 7.2 6 5.9 5.8 5.7 0.2 0.2

0.2 0.2 0.2 0.2 0.2 Characters E T A O I N S R H L D C U M 0.2 0.2

0.3 0.2 0.2 0.2 4 7.2 5 9.7 7.2 6 5.8 5 3.7

l e (i n p e r c e n t a g e )

1 2 3 ● ○ ○ 1 2 3 Characters E T A O I N S R H L D C U M P F G W B Y . , V K ‘ 1 J 1 9.7 6.7 6 5.9 5.8 5 3.7 3.3 3.3 2.7 2.2 2.2 1.8 1.8 1.6 1.5 1.2 5.7 5 3.7 3.3 2 7.2

1.8 1.8 16 1.5 1.5 1.1 1 0.8

0.8 0.6

0.2 0.2

T a b l e 3 : A c c u m u l a ti v e f r e q u e n c y o f u s e f o r e a c h b u tt o n a

o m p

K )

s c

(US)

1 2 ub o ● ○ ○ 1 2 t ) m 3 e Figure p Proposed 14: r u Characters Ukeyboard layout 1 n t E 9.7 B i e T A 6.7 O 6 I N 5.8 S R 5 ● H 3.7 ○ ○ L 3.3 D 3.31 C 2.72 U 2.2 M 2.23 P 1.8 Characters 1 F 1.8 E 9.7 G 1.6 T W A 6.7 B 1.5 O 6 Y 1.2 .I N 5.8 , ) S V 0.8 R 5 K 0.6 U H 3.7 n ‘ L 3.3 i D 3.3 t 1 0.2 e C 2.7 J d U 2.2 0 0.2 M Table 4: Some 2.2 “ K r P keyboard layout t r 1.8 i a~F arrangement using 1.8 e n Characters i differentB d mechanisms 1.6 g lG r E d lW S a T o 1.5 eB t i A m a Y Table l4 illustrates 1.2 O ( . several l way t of I c U positioning keyboard e e , N V 0.8 S K 0.6 R ‘ H L 1 0.2 ○ ○ ○ 2 7.2 1 2 3 5.7 5 3.7 3.3 6 5.9 5.8 5.7 5 3.3 ○ ○ 2.2 2.2 1.8 3 7.2 6 1.2 5.8 5.7 0.8 5 0.6 0.4 3.3 0.3 2.2 0.2 2.2 1.8 0.2 ○ 4 5 6 5.9 5.8 5.7 ○ ○ ○ ○ 3.3 2.7 ○ 7 8 3 7.2 4 5 6 3 ○ ○ ○ ○ ○ ○ 4 7.2 7 8 9

○ 4 ○ 5 ○ 6 ● ● ○ ○ ○ ○ ○ ○ ○ 1 0 1 1 1 2

○ ○ ○ ● ○ ○ ○ ○ ○ 5 9.7 7.2 ○ 6 ○ 5.8 ○ ● ○ ○ 1 3 1 4 1 5 ● ○ ○ 1 ○ 6 ○ 1 7 ○ 1 8 1 3 1 4 1 5 ● ○ ○ 1 ○ 6 ○ 1 7 ○ 1 8

○ ○ ○ 6

○ 4 ○ 5 ○ 6 ● ● ○ ○ ○ ○

1.8 2 1.8 16 7.2 1.5 1.5 5.9 1.1 1 5.7 0.8 5 3.7 3.3 0.2 0.2 1.8 0.2 1.8 16 1.5 1.5 1.1 1 0.8

○ 2.2 9 1.8 4 1.8 1.6 7.2 1.5 1.2 5.9 5.8 5.7

○ 5 ○ 3.7 ○ 1 ○ 0 3.3 1 ○ 1 1 ○ 2 5 9.7 1.6 7.2 1.5 6 1.2 1.1 5.8 5 3.7

○ ○ 2.2 ○ 6 1.5 1.2 1.1 0.8

1.2

0.8 0.6 0.4 0.3

3.3 2.7 0.2 0.2 2.2 0.2 1.8 0.2 1 1.8 2 1.6 9.7 1.5 7.2 6.7 1.2 6 5.9 5.8 5.7 5 5 3.7 3.7 3.3 3.3

3.3 0.2 0.2

0.3 0.2 2.2 0.2 0.2 5 9.7 7.2 1.5 6 5.9 5.8 5.7 5.8 5 3.7 1.2 1.1 0.8

1.6 7.2 1.5 7.2 6 5.8 5.7 5 3.3 1.2 1.1

3

4

0.3 0.2

b u tt o n s w h e n e m p l o y s d if f e r e n t d e s i g n m e c h a n i s m . F r o m t h e r e s u lt , it s e e m s t h

at ar ra n g e m e nt of b ut to n 1 to 6 th at e m pl o ys c o m bi n at io n of fr e q u e n c y of us e, h a n ds sk ill , ea sy -t ore m e m b er , fi

n g er s sk ill m ec h a ni s m s se e m s v er y at tr ac ti v e. T h er ef or e, in th is p a p er , th is c o m bi n at io n is c h os e n in d es ig ni n

g k e y b o ar d la y o ut fo r bl in d p e o pl e. Fi g ur e 1 2 is ; h e n ce , re dr a w as sh o w n in Fi g ur e 1 4.

USION
This paper presents a new computer keyboard layout for blind people. The research results show that Braille character code is very attractive to be used for designing the layout. Many mechanisms for arrangement the key are investigated and the results shows that to type Thai Braille character code, the keyboard layout requires add/drop cells button. In addition, the buttons representing point 1 to 6 of the Braille code must be in order of 5 3 1 2 4 and 6 later than 1 2 3 4 5 and 6, which has been used in many keyboard currently available on the market.

7. REFEREN CES
[1] A Servey on incapability people from National Statistical Office, Thailand, 2001. http://service.nso.g o.th/nso/data/data2 3/stat_23/toc_1/1. 1.7-5.xls [Accessed 20 June 2006]

[2] Braille keyboard http://www.rnib.or g.uk/xpedio/group s/public/document s/PublicWebsite/p 6 . ublic_notetakingin fosheet.hcsp#P56_ 4057 C[Accessed 31 July O2006] [3]N Portset BrailleKey Chttp://www.portset L.co.uk/braillekey1.

h t m [ A c c e s s e d 3 1 J u l y 2 0 0 6 ] [ 4 ] P o r t s e t B r a i l l e K e y G 2 h t t p[5 : / / w w

w . p o r t s e t . c o . u k / b r a i l l e k e y g 2 . h t m [ A c c e s s e d 3 1 J u l y 2 0 0 6 ]

I L L E X E L B r a i l l e A s s i s t a n t Q W E R T Y K e y b o a r d h t t p : / / w w w . t r i c a r e . o

] B R A

s tid=19 d [Accessed 31 July . 2006] m[6] ELBA i http://www.tvi-eb. l com/products/elba. / html c [Accessed 31 July a 2006] p [7] Humanware / BrailleNote a mPower PPC for c blind c http://www.pdamo _ biz.com/show_ne s ws.asp?NewsID=4 o 5695&PN=1 l [Accessed 31 July / 2006] T [8] S. Zhai, M. Hunter, e and B. A. Smith, c “Performance h Optimization of n Virtual o Keyboards”, IBM l Almaden Research o Center, report, g p.89-129, 2002. y http://www.almad 3 en.ibm.com/u/zhai . /papers/ZhaiHunte c rSmithHCIGalley. f pdf m ? P R O D U C T I D = 1 0 0 8 2 2 & t e c h i d = 1 & c a


				
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