Mamoru Hoshi

Fast Computation of Similarity Based on Jaccard Coefficient for Composition-Based Image Retrieval

This paper proposes an algorithm and data structure for fast computation of similarity based on Jaccard coefficient to retrieve images with regions similar to those of a query image. The similarity measures the degree of overlap between the regions of an image and those of another image. The key idea for fast computation of the similarity is to use the runlength description of an image for computing the number of overlapped pixels between the regions. We present an algorithm and data structure, and do experiments on 30,000 images to evaluate the performance of our algorithm. Experiments showed that the proposed algorithm is 5.49 (2.36) times faster than a naive algorithm on the average (the worst). And we theoretically gave fairly good estimates of the computation time.

A feature independent of bit rate for twinvq audio retrieval

In this paper we propose an audio feature for TwinVQ audio retrieval. For making effective audio database, we consider that these two techniques (compression and feature extraction) are dealt with on one platform. The proposed audio feature satisfies the following requirements: 1) independent of bit rate; 2) extractable from compressed data without decoding; 3) computable in the framework of TwinVQ. We show that the autocorrelation coefficient is theoretically independent of bit rate and confirm experimentally that the feature computed from CD audio data is actually independent of bit rate.

A method for retrieving music data with different bit rates using MPEG-4 TwinVQ audio compression

The present paper describes a method for indexing a piece of music using the TwinVQ (Transform-domain Weighted Interleave Vector Quantization) audio compression (MPEG-4 audio standard). First, we present a framework for indexing a piece of music based on the autocorrelation coefficients computed in the encoding step of TwinVQ audio compression. Second, we propose a new music feature that is robust with respect to bit rate based on the fact that the i-th autocorrelation coefficient with bit rate B1 of a piece of music computed in the encoding step of TwinVQ audio compression can approximate the j-th autocorrelation coefficient with bit rate B2 of the piece of music where i= left lfloor frac B_1 B_2 j right rfloor, and on the wavelet transform. Finally, we perform retrieval experiments on 1,023 pieces of polyphonic music with bit rate (8 kbps, 12 kbps, 16 kbps, 20 kbps, 24 kbps, 28 kbps, 32 kbps, 36 kbps, 40 kbps, and 44 kbps). The experimental results indicate that the proposed music feature for indexing has excellent retrieval performance for queries of various bit rates.

Enumerative coding for k-ary trees

We propose an efficient code for k-ary trees and give the encoding and decoding algorithms based on enumeration. The code has better performance than the commonly used pre-order coding for k-ary trees when k is larger than two, and is asymptotically tight in the sense that the coefficient of the linear term of length function of codewords for trees is the best possible.

Keyword search on hybrid XML-relational databases using XRjoin

Keyword search on databases has been popularized since it enables users to get information under databases without any knowledge of the schema or query languages. There are a number of keyword-search techniques on both RDB and XML DB, but those may still miss appropriate answers when some substructures of XMLs are related by relational linkage information. To overcome this problem, we consider integration of XML and relational data and this paper proposes a new method of keyword search on hybrid XML-Relational databases. As a new concept, a new join operator, named XRjoin, is designed and utilized to join XML with relational data. Experiments on DB2 v9.5 show effects of our proposal.

A reversible distribution converter with finite precision arithmetic

This article presents a reversible distribution converter such that the source sequence of finite length can be exactly reproduced from the target sequence generated by the converter. All the calculations needed are done with finite precisions along the line of arithmetic codes.

mm-GNAT: index structure for arbitrary L p norm

For fast epsiv-similarity search, various index structures have been proposed. Yi et at. proposed a concept multi-modality support and suggested inequalities by which epsiv-similarity search by L1, L2 and Linfin norm can be realized. We proposed an extended inequality which allows us to realize epsiv-similarity search by arbitrary Lp norm using an index based on Lq norm. In these investigations a search radius of a norm is converted into that of other norm. In this paper, we propose an index structure which allows search by arbitrary Lp norm, called mm-GNAT (multi-modality support GNAT), without extending search radius. The index structure is based on GNAT (geometric near-neighbor access tree). We show that epsiv-similarity search by arbitrary Lp norm is realized on mm-GNAT. In addition, we performed search experiments on mm-GNAT with artificial data and music data. The results show that the search by arbitrary Lp norm is realized and the index structure has good search performance.

Coding of ordered trees

We study the asymptotic growth of ordered trees, and give important insights in coding of trees from the information theoretic viewpoint. Specifically, we give the optimal length function in a sense that the Kraft inequality is satisfied with equality. It is revealed that the commonly used pre-order coding for special classes of trees are asymptotically tight, but not always for many trees.

Random number generation with cost by an interval algorithm

We consider the problem of generating an i.i.d. random sequence X/sup n/=X/sub 1//spl middot//spl middot//spl middot/X/sub n/ (of length n) subject to a generic distribution q=(q/sub 1/,q/sub 2/,q/sub N/) by using a biased M-sided coin with probability p=(p/sub 1/,p/sub 2//spl middot//spl middot//spl middot/p/sub M/) and cost c=(c/sub 1/,c/sub 2/,c/sub M/) for each of M-sides.

The number of paths in boundary restricted Pascal triangle

In this talk, we provide several forms of the generator for counting the number of paths in the boundary restricted Pascal triangle. In the section 1, we consider the problem of single boundary. In the section 2, we proceed the discussion into the problem of two boundaries. Specifically, we give three seemingly different forms to count the number of paths. If time permits, we will give the proof of the equivalence between them. The study treated in the paper is a continuation of papers [2, 3].