Fumihiro Matsuo

GENAS: a database system for nucleic acid sequence analysis.

A database system, named GENAS (GENe Analyzing System), for computer analysis of sequence was constructed using Adbis which is a relational database management system (1). GENAS enables us to retrieve any sequence data from EMBL nucleotide sequence data library (2) and readily to analyze them (if necessary, together with private data) by various application programs in a interactive manner. Analysis of structure of replication origin of replicons was demonstrated using this system.

Musical sequence comparison for melodic and rhythmic similarities

We address the problem of musical sequence comparison for melodic similarity. Starting with a very simple similarity measure, we improve it step-by-step to finally obtain an acceptable measure. While the measure is still simple and has only two tuning parameters, it is better than that proposed by Mongeau and Sankoff (1990) in the sense that it can distinguish variations on a particular theme from a mixed collection of variations on multiple themes by Mozart, more successfully than the Mongeau-Sankoff measure. We also present a measure for quantifying rhythmic similarity and evaluate its performance on popular Japanese songs.

A Method of Extracting Related Words Using Standardized Mutual Information

Techniques of automatic extraction of related words are of great importance in many applications such as query expansion and automatic thesaurus construction. In this paper, a method of extracting related words is proposed basing on the statistical information about the co-occurrences of words from huge corpora. The mutual information is one of such statistical measures and has been used for application mainly in natural language processing. A drawback is, however, the mutual information depends mainly on frequencies of words. To overcome this difficulty, we propose as a new measure a normalize deviation of mutual information. We also reveal a correspondence between word ambiguity and related words using word relation graphs constructed using this measure.

Efficient storage and retrieval of very large document databases

The authors have developed an information retrieval system named AIR (Augmented Information Retrieval system), which might be one of the most efficient systems for very large document databases. AIR can store the document data compactly and retrieve them quickly. The techniques bringing AIR to the high efficiency, the data compression, the quick keyword index, and the automatic keyword selection, are discussed. These techniques, which are based on the statistical properties of word occurrence, are fairly simple, so that the information retrieval systems employing them can be implemented with ease. The data compression technique reduces English text by a factor of 4. The quick keyword index decreases the average number of disk accesses to retrieve a keyword to about 0.3. The automatic keyword selection technique roughly halves both the number of different keywords and the size of the inverted file with only 2% loss of retrieval power.

A tool for constructing production systems on the deductive database system adbis

Abstract The authors have designed and implemented a tool for constructing production systems on the deductive database system Adbis that is a relational database management system with inference functions based on Horn set refutation procedures. The production systems developed by using this tool have the following characteristics: (1) users of them can handle large factual data as well as production rules since they are linked with a relational database through the Horn set refuter; (2) the users are able to easily perform a backward reasoning because the left-hand side and right-hand side of production rules are syntactically symmetrical; (3) the inference functions based on Horn set refutation procedures can be used not only for checking the applicability of production rules to data accessed by the production rules, but also for expressing and checking the integrity constraints which the data satisfies. This facility for integrity checking may be useful for debugging; (4) in future, the performance of the production systems are expected to be improved by using the results of much research in Horn set refuters and Prolog.