A Chinese Characters Coding Scheme for Computer Input and Internal Storage

A CHINESE CHARACTERS CODING SCHEME FOR COMPUTER INPUT AND INTERNAL STORAGE Chorkin Chan, Computer Centre, University of Hong Kong, Hong Kong Abstract A coding scheme for inputting Chinese characters by means of a conventional keyboard has been developed. The code for each Chinese character is composed of two strings of keys, one corresponds to the spelling and the other the ideo- graphic property of the character. Each code requires no more than seven keys (average five and a half keys) and 99.5% of the ten thousand characters in a dictionary 'XianDai HanYu CiDian' have unique codes. Each input code can be packed into 32 bits for internal representation. Introduction of eighteen pairs can be easily removed by deleting one member of each pair from the vocabulary because they are either 'dead' characters appearing in ancient classics only or they can be replaced by other characters of equivalent meaning. The non-uniqueness of the remaining eight pairs can be removed also by either changing the ideographic pattern or the spelling of one of the members in each pair. Thus, by means of these remedial measures, this coding scheme offers a unique code to each of the ten thousand characters found in this dic- tionary. The list of characters sharing the same codes is in Table 1 together with the suggested remedies to overcome the problem of non-uniqueness. Over the last few years, encoding Chinese characters has become a very active subject of research. Numerous papers have appeared, mainly written in Chinese (hence difficult to be refer- enced in English), proposing various kinds of inputting schemes. Unfortun- ately, most of these papers offered only the ideas without accompanying implemen- tation and experimentation. This paper presents a coding scheme of Chinese characters based on their ideographic properties as well as their spellings so that a conventional typewriter keyboard can be used for inputting purposes. This scheme has been implemented at the University of Hong Kong using an IBM 3031 under VM/CMS. Without a proper output device to display the Chinese characters, when the code of a Chinese character is entered, the address of that character (where it can be found) in a dictionary 'XianDai HanYu CiDian' is displayed. This is awkward but still sufficient to prove the correctness of the code recognition procedure. The Coding Scheme for Inputting In this scheme, a code for a Chinese character consists of two strings of symbols concatenated together. One string of three symbols corresponds to the ideographic radicals the character is composed of. The other of no more than four symbols is the spelling of the character. Corresponding to each of the ten thousand characters in the diction- ary 'XianDai HanYu CiDian', with the exception of twenty six pairs, there exists a unique code in this scheme. In other words, this coding scheme is 99.5% unique. Furthermore, among these pairs of characters sharing the same codes in a pair-wise manner, the non-uniqueness The Spelling of Chinese Characters There are two standard systems to spell Chinese characters, one …

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