MODELING MULTI-SCRIPT TEXT EDITING BASED ON ONLINE HANDWRITING RECOGNITION BY DANIEL KEFALE TIRFIE A THESIS SUBMITTED TO THE SCHOOL OF GRADUATE STUDIES OF ADDIS ABABA UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN COMPUTER SCIENCE JUNE 2008 ADDIS ABABA ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES FACULTY OF INFORMATICS DEPARTMENT OF COMPUTER SCIENCE MODELING MULTI-SCRIPT TEXT EDITING BASED ON ONLINE HANDWRITING RECOGNITION BY DANIEL KEFALE TIRFIE Approval Board of Examiners 1. Chairman, Department Graduate Committee Signature ___________________________ ___________ 2. Advisor ___________________________ ___________ 3. Examiner ___________________________ ___________ 4. Examiner ___________________________ ___________ - ii - Acknowledgement I would like to thank all those people for continuing support and help in making this thesis possible. First of all, I would like to thank my advisor, Dr. Solomon Atnafu, for his support, encouragement and guidance throughout this study. I would also like to thank Mr. Daniel Yacob and Menasse Zahodu for sharing of valuable ideas and encouragement. My colleagues Abera Abebaw, Nesredin Suliman and Seble Hailu are also grateful for professional advice and encouragement. Especially Abera Abebaw, for all those long hours he has spent to improve my work. My thanks extend to Binyam Ephrem and Lubna Ahmed, who has spent many hours for proof reading, and to those who participated in the experiment. My great thanks extend to Ashenafi Shiferaw, who has offered me his laptops to do my work where it was very difficult to finalize my work on time without the laptops. Thank you, Ashu. I would also take this opportunity to thank GNU and other Free Software foundations. Finally, I thank my family and friends for years of encouragement. I am sure that no one will be happier or prouder to see me complete this course of study than my parents and my chick. Hi Mom, Dad, and Berzie! - iii - Table of Contents Content Page LIST OF TABLES ....................................................................................................................................................VI LIST OF FIGURES ................................................................................................................................................ VII LIST OF LISTI#GS ..............................................................................................................................................VIII LIST OF APPE#DIX ............................................................................................................................................VIII LIST OF ACRO#YMS.............................................................................................................................................IX ABSTRACT................................................................................................................................................................ X 1. I#TRODUCTIO#..................................................................................................................................................1 1.1 OVERVIEW .................................................................................................................................................. 1 1.2 RESEARCH PROBLEM .................................................................................................................................. 3 1.3 MOTIVATION .............................................................................................................................................. 4 1.4 OBJECTIVES ................................................................................................................................................ 5 1.5 SCOPE AND LIMITATION.............................................................................................................................. 6 1.6 METHODOLOGY .......................................................................................................................................... 7 1.7 ORGANIZATION OF THE DOCUMENT............................................................................................................7 2. REVIEW OF RELATED LITERATURE............................................................................................................ 9 2.1 FONT, CHARACTER AND SCRIPT.................................................................................................................. 9 2.2 INPUT METHODS FOR HANDHELD DEVICES ..............................................................................................12 2.3 HANDWRITING RECOGNITION ................................................................................................................... 13 2.4 MULTILINGUAL COMPUTING .................................................................................................................... 14 2.5 REVIEW OF RELATED WORKS ................................................................................................................... 17 2.5.1 Online Handwriting Recognition for Latin script ............................................................................... 17 2.5.2 Online Handwriting Recognition for Ethiopic script .......................................................................... 19 2.5.3 Multi-lingual Script processing...........................................................................................................26 3. DESIG# OF A MODEL FOR MULTI-SCRIPT TEXT EDITI#G ................................................................32 3.1 DESIGN GOALS ......................................................................................................................................... 32 3.1.1 Performance........................................................................................................................................33 3.1.2 End User Requirement ........................................................................................................................34 3.2 DESIGN CONSIDERATION .......................................................................................................................... 35 3.2.1 Constraints of the Handheld Devices ..................................................................................................36 - iv - 3.2.2 Character Encoding ............................................................................................................................39 3.2.3 Text Rendering and Fonts ...................................................................................................................39 3.3 DESIGN APPROACHES ............................................................................................................................... 40 3.4 A MODEL FOR MULTI-SCRIPT TEXT EDITING ...........................................................................................43 3.4.1 A Model for Ethiopic OHWR Text editing...........................................................................................47 3.4.2 The OHWRS for Latin Script...............................................................................................................54 4. IMPLEME#TATIO# OF THE MULTI-SCRIPT TEXT EDITI#G MODEL..............................................57 4.1 HANDHELD PLATFORM SELECTION...........................................................................................................57 4.2 ALTERNATIVES FOR IMPLEMENTATION ENVIRONMENT ............................................................................59 4.2.1 Using PiLoc API.................................................................................................................................. 60 4.2.2 Using Palm OS Developer Suite.......................................................................................................... 62 4.2.3 Using SuperWaba SDK .......................................................................................................................63 4.2.4 Using J2ME IDE .................................................................................................................................65 4.2.5 Discussion ...........................................................................................................................................67 4.3 DESIGN OF ETHIOPIC FONT FOR PALM OS ................................................................................................68 4.4 PROTOTYPE IMPLEMENTATION ................................................................................................................. 71 5. EXPERIME#TAL RESULTS ............................................................................................................................76 5.1 INTRODUCTION ......................................................................................................................................... 76 5.2 METHOD ................................................................................................................................................... 77 5.2.1 Subjects ...............................................................................................................................................77 5.2.2 Apparatus ............................................................................................................................................77 5.2.3 Procedure............................................................................................................................................77