A Minimum Chord Stenograph Keyboard for Blind and Sighted Users
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A Minimum Chord Stenograph Keyboard For Blind And Sighted Users by Zhongzhi Hu B.A.Sc., Beijing Institute of Technology A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS OF THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF ELECTRICAL ENGINEERING We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA 1992 © Zhongzhi Hu, 1992 Abstract This thesis deals with the design and testing of an experimental steno- graph keyboard for blind and sighted users. The new keyboard, called the Minimum Chord Stenograph (MCS), is presented. It comprises two panels of six keys, one for each hand. Relocation of the fingers above the keys is at a minimum. A coding scheme for MCS was developed to allow ex act phonemic description of the text or speech to be entered by alternate hand typing. Experiments were carried out with the MCS and with the standard Stenograph-Boswell keyboards. The time between successive movements of hands on the keyboards was precisely measured live with a 386 com puter and the statistics have been compiled and analyzed. The results show that the MCS’ performance (WPM) is significantly better than the stan dard stenograph-Boswell; the problem of training time for the stenograph seems to be solved at least at the level of initial competence. Extrapolating from the published results for QWERTY, MCS has much better performance than QWERTY at the initial stage. In conclusion, MCS keyboard may pro vide an efficient alternative to the existing standard stenograph keyboard and to the QWERTY keyboard. II _______________________ _______________________________ In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. (Signature) Department of The University of British Columbia Vancouver, Canada Date f’ / DE-6 (2/88) Vi VIII Table of Contents Abstract List of Figures List of Tables. Acknowledgment ix Chapter 1 Introduction 1 1.1 Background 2 1.2 Applications 3 1.3 Thesis Outline 4 Chapter 2 A Review of the Various Keyboards 6 2.1 Typewriter Keyboards 7 2.2 Chord Keyboards 11 2.2.1 Stenotype Keyboards 11 2.2.2 Chord Keyboards 15 2.3 Comparisons of QWERTY and Chord Keyboards 17 2.4 Discussion 22 111 Chapter 3 Minimum Chord Stenograph Keyboard Design . 24 3.1 MCS Keyboard Layout 24 3.2 MCS Coding 27 3.3 MCS Implementation 39 3.3.1 Boswell Keyboard System 39 3.3.2 MCS Implementation 41 3.4 Discussions of MCS Keyboard Layout 41 Chapter 4 Experiment and Results 43 4.1 Experiment 44 4.1.1 Subjects 44 4.1.2 Apparatus 46 4.1.3 Procedure 47 4.2 Results 49 4.2.1 Results with MCS 49 4.2.2 Results with Boswell 67 4.3 Discussions 70 4.3.1 Discussion on MCS Coding 70 4.3.2 The MCS Keyboard Compared with the Standard Stenograph Boswell Keyboard . 72 iv 4.3.3 The MCS Keyboard Compared with Gopher’s Chord Keyboard 74 4.3.4 The MCS Keyboard Compared with QWERTY Keyboard 76 Chapter 5 Summary and Suggestion 79 5.1 Summary 79 5.2 Suggestion 83 References 84 V List of Figures Figure 1 The QWERTY Keyboard .8 Figure 2 The Dvorak Keyboard .9 Figure 3 Stenograph Keyboard 12 Figure 4 Palantype Keyboard 12 Figure 5 Boswell Keyboard 13 Figure 6 Gopher two-hand chord keyboard 16 Figure 7 Encoding Sequence on Stenograph and QWERTY 19 Figure 8 Learning curves of 2 groups typing free text two- hand chord keyboard and on QWERTY keyboard. 21 Figure 9 Keyboard Layout for MCS 26 Figure 10 Block Diagram of Apparatus Setup 46 Figure 11 Learning Curves for Subjects with MCS keyboard 51 Figure 12 The distribution of interstroke intervals for subjects with MCS in the first and last tests 53 Figure 13 Response Time to Consonants 56 Figure 14 Response Time to Vowels 57 Figure 15 Examples of Distribution of Response Time to Consonants for Subject MA 61 vi Figure 16 Examples of Distribution of Response Time to Vowels for Subject MA 62 Figure 17 The Entry Error Rates for MCS Subjects 63 Figure 18 Examples of Motor Errors 65 Figure 19 Examples of Representation Errors 66 Figure 20 Learning Curve for Novice Subject BA with Boswell Keyboard 68 Figure 21 Learning Curve for Experienced Subjects with Boswell Keyboard 69 Figure 22 The Normalized Variance vs. The Average Information Rate with MCS 71 Figure 23 Performance of MCS Keyboard and Boswell Keyboard with Blind and Visually Impaired Subjects 73 Figure 24 Performance of MCS Keyboard and Gopher’s Two-hand Chord Keyboard with control Subjects. 75 Figure 25 Performance of MCS Keyboard and QWERTY Keyboard with Sighted Subjects 77 vii List of Tables Table 1 Performance Data for Boswell in FP Mode . 14 Table 2 English Vowel Phonemes 27 Table 3 English Consonant Phonemes 28 Table 4 The Relative Frequency of English Vowels . 31 Table 5 The Relative Frequency of English Consonants 32 Table 6 The Average Reaction and Percentage Error for 31 Chord Patterns 34 Table 7 Coding Between Keys and Consonants 37 Table 8 Coding Between Keys and Vowels 38 Table 9 The Characteristics of the Subjects 45 Table 10 Initial Acquisition on MCS 49 Table 11 Average Response Times to Consonants for Two Control Subjects 58 Table 12 Average Response Times to Vowels for Two control Subjects 59 vrn Acknowledgment I would like to thank my supervisor, Dr. M. P. Beddoes, for his many fruitful discussions and helpful suggestions, as well as for his invaluable assistance in preparing the thesis. I am indebted to Dr. P. Graf of Psychology of UBC for his helpful discussions and assistance, N. Newell and T. Markoc for their assistance with some software implementation, and 13 subjects for their cooperation. Thanks are also due to Drs. C. A. Laszlo and G. F. Schrack for their careful reading and correction of this thesis. Special thanks are given to my wife, Lei Jin, for encouragement and understanding throughout my graduate study. I would wish to acknowledge also financial and equipment support from the following organizations: a. Financial support: Operating grant 553462 from the Science Council of British Columbia; and Operating grant 583290 from the National Science and Engineering Council of Canada; b. Equipment support: 8 Boswell keyboards from the Boswell International Technologies Ltd., Vancouver, British Columbia. ix Chapter 1 Introduction Stenotype machines are the fastest means for encoding verbal infor mation into print or speech. Systems have been developed for the British Palantype and the American Stenograph, and these have been operated at real speech rates by skilled stenotypists. However these kinds of ma chines are difficult to learn and operate. This thesis deals with the design of and testing of an experimental stenograph keyboard for blind and sighted users. Our objective is to overcome the problems with existing stenograph keyboards and design a new keyboard, which is fast and easier to learn and operate. The new keyboard layout is called the Minimum Chord Steno- graph (MCS). Relocation of the fingers above the keys is at a minimum; phonemes are the input quantity. A suboptimum coding scheme for MCS ensures that the maximum information input rate can be reached. The ex periments show that less time is needed to learn the keyboard than needed for the standard stenograph-Boswell keyboard and it is faster than Boswell and QWERTY keyboards. In the next two sections, some background and applications of the stenotype machines are described; and in the last section, the thesis outline is presented. 1 1.1 Background Some recent developments in communication aids for the speech im paired have featured synthetic speech output [1]. Like most communication aids, however, they suffer from the problem of data rate restriction, where information transfer is much slower than between able-bodied persons. Typical conversational speech rates are between 150 and 250 words per minute, whereas a good typist can only encode at 60 to 80 words per minute. A dexterous person can therefore communicate via a conventional typewriter keyboard at only about one third the rate of normal speech. Synthetic speech output may be derived from typed information, but con versation by this means is restricted by the low typing rate. A number of systems have been developed to improve the effective typing rate, e.g. ergonomic keyboards, stored word lists [2], etc., but none have achieved sufficient improvement to allow unrestricted conversation at normal rates. Nevertheless, a mechanical keyboard method for encoding verbatim speech has existed for many years — the stenotype shorthand machine. Stenotype keyboard systems are phonetically based. A spoken word is analyzed into its constituent syllables. Each syllable is then typed, with a coded quasi-phonetic spefling, in one stroke ( called a “chord”). This allows a significant speed advantage over conventional QWERTY 2 keyboard operation, hence a trained stenotypist can type verbatim speech at speech rates. A trained stenotypist can therefore record speech via these keyboards without restriction of either speed or vocabulary. 1.2 Applications Stenotype keyboards were first [3] employed for rehabilitation purposes in January 1977, when Jack Ashely, a British Member of Parliament, be gan monitoring debates on a real-time speech captioner. This device takes input from a Palantype keyboard, which is operated by a professional steno typist.