DATE: 2003-10-17 Time: 12:28 AM

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ISO/IEC JTC 1/SC 2/WG 2 N2661

Date: 2003-10-17

ISO/IEC JTC 1/SC 2/WG 2
Universal Multiple-Octet Coded Character Set (UCS) - ISO/IEC 10646

Secretariat: ANSI

Title:

Clarification and Explanation on Tibetan BrdaRten
ProposalPrecedes:WG2 N2558, N2621 and Critique Papers N2624, N2635,
N2637 and N2638

Source:Action:Distribution:

China National Body
To Discuss at WG2 #44

SC2/WG2 Experts

This paper is to further clarify and explain issues in N2621, the Revised Proposal onTibetan BrdaRten, and reply the critiques in Papers N2624, N2635, N2637 andN2638.
The Chinese National Body would like to reaffirm its position , that the encoding
Model, Tibetan Basic Letter Plus BrdaRten has been being used in Tibetan language
for machine processing, which is the most suitable model for China to facilitate andspeed-up the migration of Tibetan system and e-data in China to UCS, therefore,
China insists on the proposal to encode BrdaRten in to BMP of UCS forinteroperability.

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1. Why BrdaRten?

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Is BrdaRten necessary ?

China does not intend to challenge WG2 general principle on pre-composedcharacter encoding, but would like to objectively analyze the specificlanguage/script for its encoding.
(1) Tibetan BrdaRten has been being an element for machine processing
since typewriter age, which is ease to recognize by eyes, ease to process bymachine. Only because of the capacity of the machine, the number of used
BradaRten is limited to small amount. The lead letters and keyboard of theTibetan typewriter are shown in Figure 1 and 2.
Figure 1. Lead Lettersof BrdaRten

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Figure 2: Typewriter with BrdaRten Keyboard.

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Page: 4 of 9(2) When PC and PC based desk-top typesetting system is used in Tibetan
language area, the BrdaRten characters are adopted in large scale for input,
storage, processing and display-printing in China. According to the statistics
based on the Tibetan data base by The NorthWest Minority Nationality
University, among the 18 millions character text, the basic Tibetan letters
appear 40.97%, while the BrdaRten is 23.07% (the Intersyllabic Mark 0F0Band Phrase Separator 0F0D occupy 34.73% ). Another statistics jointly madeby China Institute of Standardization and Qinghai Normal University issimilar :45.62% and 23.59% based on 19 millions character data base. Thisimplies that every two basic Tibetan letters accompany one more
BrdaRten in average ! This high frequency hints us that the BrdaRten form
could not be ignored.
(3) Since early 1990s, the Tibetan systems by Founder , Huaguang and Tongyuan
in later, are widely used in newspapers, magazines, publishing Houses,
Central and Local Translation Bureaus, Tibetology Research Center, local
governments , Tibetan Radio /TV Stations in Gansu, Qinghai, Sichuan,Yunnan and Tibet. All of official publications are utilizing Tibetan basic
letters plus BrdaRten coding model although the code pages amongst Founder,
Huaguang and Tongyuan are different in repertoire and code position. It isroughly estimated that such users exceed 3000 (for registered users, Founder– 600-700, Huaguang – 700-800, Tongyuan – 1500, BanZhiDa- >100 ), thee-data with BradaRten exceeds several billions characters. This hugeamount of e-data with mission-critical users is another fact which can not beignored.
Therefore, encoding BrdaRten as it is in UCS/BMP is necessary because of its history,
its usage practice , its usage frequency, and the huge amount electronic data existed(legacy) in the coding model. The next paragraph will give more fact and reasonscompared with the dynamically-combining model.

2. Is BrdaRten Sufficient ?
The answer is Yes in general. The proposed BrdaRten characters in N2621 are
sufficient for modern Tibetan language. Together with Tibetan basic characters,
BrdaRten can cover 100% modern Tibetan written language, even most ancient
Tibetan classics. This is the goal of N2621.
On the other hand, in order to meet the requirement for digital Tibetan ancient classics,
another 6000 BrdaRten character set has been prepared for national standard
pending on its code position, which may be placed in Private Use Zone, or in
Supplementary Plane. Actually, such rarely used BrdaRten characters in Huaguangsystem are being used for publishing and proof-reading the large-scale classics

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Page: 5 of 9Tibetan Buddhism 藏文《大藏经 甘珠尔 丹珠尔》(bkav bstan vgyur, bstan vgyur
and bkav bstan), which are printed in 290,000 pages, about 290 millions Tibetan
characters containing BrdaRten.
Nevertheless, proposed and to be proposed BrdaRten set would not be able toexhaustedly cover any STACKS , just like N2624 said, there is also exception even forexisting Unicode character encoding model, the highly unusual stacks that containmore than one consonant-vowel combination in a vertical arrangement (thesecontravene the normal rules of Tibetan writing, and are considered beyond the scopeof plain text rendering).

3. BrdaRten vs. Dynamically-Combining, Pros and Cons

Anything has its positive side and negative side, so does BdaRten Model or
Combining Model for Tibetan. What Chinese Tibetan people need is an advanced andmature technique to implement the model easily, quickly and at lower cost.
We carefully studied and tested the beta version Uniscribe Complex-Script Rendering
Engine with Ximalaya OpenType Font as an implementation of
Dynamically-Combining Model purely based on 0Fxx . It looks smart and interesting,but still in developing stage. It would be a good solution in the future, but,unfortunately, it has not proved as a MATURE product yet, in user-friendliness forBrdaRten key-in and editing.
Rather than arguing whether or not this is due to the coding scheme, we would like tomake a comparison of dynamically-combining model with BrdaRten model. For
brevity, 0FXX is used for Dynamically-Combining Coding Model for Tibetan, while
BRDARTEN stands for Tibetan Basic Letters Plus BdaRten Coding Model in thediagrams below.

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Figure 3: BrdaRten Model for Migration, Processing and Rendering
Current String

Converted to UCS for Processing

Rendered Glyphsꜿད་ꘋངསꜿད་ꘋངསꜿད་ꘋངས

6 chars

6 glyphs

6 chars
Tibetan String=
Basic Letters +BrdaRten Chars

Tibetan String=
Basic Letters +BrdaRten Chars
Mapping 1:1

Tibetan String=
Basic Letters +BrdaRten Glyphs

Rendering 1:1
CharCode

Data in CodePages – BdaRten
Model

Data in UCS
BrdaRten Model

BasicLetter TTF

BrdaRten TTF
FontFigure 4: Migration From BrdaRten Model to 0FXX Model for For Precessing &Rendering
Current String

Converted to UCS for Processing

Rendered To Glyphsꜿད་ꘋངསབོད་ལྗོངསꜿད་ꘋངས

9 chars

6 glyphs

6 chars
Tibetan String=
Basic Letters +BrdaRten Chars

Tibetan String=
Basic Letterswith combining
chars

Mapping 1:1

Decomposing
1:M
Data in Code
Page –BradRten Model

Data in UCSBdaRten
Model

Tibetan String=
Basic Letters +BrdaRten CharsRendering 1:1Combining
M:1

Glyph Index
For BasicLetters

Smart Font ( OpenType)Glyph Index

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(1) Customarily, the form in pure 0FXX string with no combining (see the left Tibetan
string below) is not readable by ordinary people, even the string occasionallyappears. Unfortunately, it will inevitably occur providing the rendering engine orOpenType font is missing or disabled. This kind of pure OFXX string may beeasily Romanized but not easily recognized by ordinary Tibetan people.

བོད་ལྗོངས ལྷ་སvs.

ꜿད་ꘋངསꢰ་ས

(2) Given the fact that huge amount e-data with BrdaRten, it will be more costly for
Chinese Tibetan to migrate to UCS/0FXX mode.
a) It is required to decompose all BrdaRten to be pure 0FXX string; one tomany mapping must be done.
b) It causes Not-Equal-Length-Conversion as a result, the DATA TYPE andData Base Structure (say, the field length) would change accordingly.
No one doubts the POSSIBILITY of such decomposing or mapping (as N2628
stated), but the COST and WHAT we get after the complex conversion?
(3) For character processing, apparently 0FXX makes the processing more
complicated in cursor moving, character deleting, inserting or replacing. Thecomplex-script rendering mechanism becomes required. While the BrdaRtenmodel makes processing so simple as English or Chinese processing that all
English and Chinese software could be used without major change. The reason isthat BrdaRten model changes Tibetan from so-called Complex-Script to be
the Simple-Script in a sense.
(4) For storage, BrdaRten takes less space than 0FXX string.
(5) For IME, BrdaRten is simple like Pinyin, and several implementations haveenabled word-phrase-based input . While 0FXX needs multiple keyboard pages tomanipulate that reduces user-friendliness.
(6) For OCR, in character segmentation stage, BdaRten needs vertical cutting only
(see the left picture below), while the 0FXX needs both vertical and horizontal
segmentation ( see the right picture below ), makes implementation moredifficult.

BrdaRten

0FXX(7) In post OCR processing, the 1:1 corresponding between the original image andthe recognized characters would be helpful to proof-reading applications. The
BrdaRten makes this easy to implement while 0FXX may lose thecorresponding.
(8) For sorting, 0FXX seems much simpler than BrdaRten, however, the collation ofTibetan has been developed in China.
(9) For searching, there is no apparent difference between 0FXX and BrdaRten. The
example, search letter KA, in N2638 is not convincing since such searching isDATE: 2003-10-17 Time: 12:28 AM

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semantically meaningless therefore the there is no need to decompose BrdaRten
any more.
(10) Finally, for rendering, 0FXX needs Complex-Script Engine and “Advanced”
OpenType, but BrdaRten does not.
In summary, 0FXX increases the conversion cost to migrate legacy to UCS, andalso rises the complexity in processing, storage, and rendering. In years, 0FXX
seems not the most suitable coding model, at least for China. Chinese Tibetan’s
choice is BrdaRten.
As far as INTEROPERABILITY
andINTERCHANGEABILITY,
they are our goal.
It is for
INTEROPERABILITY with outside, we are proposing BrdaRten to be encoded
in BMP not only in a National Standard, even within the UCS framework.

=============================================

The contributors of this paper are from the following companies,
institutes, organizations and universities:
Translation & Editing Bureau, Tibet Autonomous Region, China
西藏自治区翻译局Language Committee Office, Tibet Autonomous Region, China
西藏自治区藏语文工作委员会办公室
Tibet University
西藏大学
Nationalities Publishing House
民族出版社
Publishing House, China Tibetology Research Center
藏学研究中心出版社
Qinghai Normal University
青海师范大学
Beijing Founder Electronics Co., Ltd.
北京北大方正电子有限公司
Weifang Qingniao-Huaguang Co., Ltd.
北大青鸟-华光科技股份有限公司
UniHan Digital Technology Co., Ltd.
书同文数字化技术有限公司
Northwest Minorities University
西北民族大学
Software Institute, Chinese Academy of Sciences
中国科学院软件研究所
China Electronics Standardization Institute中国电子标准化研究所

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Page: 9 of 9Standardization Institute of China
中国标准化研究院
Institute of Ethnology & Anthropology, Chinese Academy of Social Sciences
中国社会科学院 民族学与人类学研究所
Department of Language Information Administration, Ministry of Education, PRC
教育部语言文字信息管理司
Department of Culture & Publicity, State Ethnic Affairs Commission, PRC
国家民族事务委员会文化宣传司
Department of Electronics Production, Ministry of Information Industry, PRC
信息产业部 电子产品管理司