• Journal of KIISE:Information Networking
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• v.32 no.4
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• pp.543-550
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• 2005

Demand for better services in the Internet has been increasing due to the rapid growth of the Internet, and hence next generation routers are required to perform intelligent packet classification. For a given classifier defining packet attributes or contents, packet classification is the process of identifying the highest priority rule to which a packet conforms. A notable characteristic of real classifiers is that a packet matches only a small number of distinct source-destination prefix pairs. Therefore, a lot of schemes have been proposed to filter rules based on source and destination prefix pairs. However, most of the schemes are based on sequential one-dimensional searches using trio which requires huge memory. In this paper, we proposea memory-efficient two-dimensional search scheme using source and destination prefix pairs. By constructing binary prefix tree, source prefix search and destination prefix search are simultaneously performed in a binary tree. Moreover, the proposed two-dimensional binary prefix tree does not include any empty internal nodes, and hence memory waste of previous trio-based structures is completely eliminated.

• The Journal of the Acoustical Society of Korea
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• v.37 no.6
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• pp.518-524
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• 2018

The cover song refers to live recordings or reproduced albums. This paper studies two-dimensional Fourier transform as a feature-dimension reduction method to search cover song fast. The two-dimensional Fourier transform is conducive in feature-dimension reduction for cover song search due to musical-key invariance. This paper extends the previous work, which only utilize the magnitude of the Fourier transform, by introducing an invariant from phase based on the assumption that adjacent frames have the same musical-key change. We compare the cover song retrieval accuracy of the Fourier-transform based methods over two datasets. The experimental results show that the addition of the invariant from phase improves the cover song retrieval accuracy over the previous magnitude-only method.

• Journal of the Korean Society for information Management
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• v.9 no.1
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• pp.55-82
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• 1992

It can be assumed that exciting improvements of technology concerning the ways in which information is stored and processed have significantly affected information science and may lead to a dramatic change of research in the field. Author co-citation analysis was used to investigate changes in research patterns of information retrieval over two time periods, 1980-1982, and 1988-1990. Nonmetric multidimensional scaling and clustering techiqes were used to create two dimensional maps displaying the changing research patterns among 22 authors as perceived by scholars citing their work over the two time periods. The co-cited author clusters and the placement of authors on the two maps both appear to correspond well with characterizations of the author's work obtained in texts and social relationships.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.94-99
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• 2000

컴퓨터의 보급과 함께 인터넷의 대중화로 많은 정보가 인터넷을 통해 제공되면서 많은 사람들이 정보통신 기반 서비스를 이용하게 되었다. 하지만 이런 서비스에 익숙하지 않은 사용자가 자신이 원하는 정보를 찾는 것은 그리 쉬운 일이 아니다. 그래서 ISP나 PC통신 업체들은 사용자들이 겪는 어려움을 해결해 주기 위한 서비스를 제공하고 있다. 그러나 사용자들의 엄청난 증가로 인해 이런 서비스를 유지하는데 많은 인력과 시간이 필요하게 되면서 질의 응답 자동화에 대한 필요성이 대두되었다. 본 논문에서는 ISP 업체 중 하나인 한메일넷의 자동 응답 시스템을 위한 FAQ 브라우징 시스템을 개발하였다. 기존의 많은 검색 서비스가 키워드들을 단순히 나열하고 이 키워드의 링크를 따라가면서 검색을 하게 하였으나 이 방식은 검색 대상에 대한 키워드 정보만을 제공하기 때문에, 문제에 대한 배경 지식이 적거나 검색 서비스 사용에 익숙치 않은 사용자가 이용하기에는 쉽지 않다. 본 시스템에서는 사용자에게 이차원상에 표현된 문서 지도를 제공해서 사용자가 쉽게 전체 검색 자료의 분포를 파악하고 검색하도록 하였다. 또한 단계별 검색이 가능하도록 해서 사용자가 효율적으로 검색할 수 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.7
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• pp.1583-1590
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• 2011

As the existing radiation scanning systems use 2-dimensional radiation scanned images, the low accuracy has been pointed out as a problem of it. This research analyzes the applicability of the stereo image processing technique to X-ray scanned images. Two 2-dimensional radiation images which have different disparity values are acquired from a newly designed stereo image acquisition system which has one additional line sensor to the conventional system. Using a matching algorithm the 3D reconstruction process which find the correspondence between the images is progressed. As the radiation image is just a density information of the scanned object, the direct application of the general stereo image processing techniques to it is inefficient. To overcome this limitation of a stereo image processing in radiation area, we reconstruct 3-D shapes of the edges of the objects. Also, we proposed a new volume based 3D reconstruction algorithm. Experimental results show the proposed new volume based reconstruction technique can provide more efficient visualization for cargo inspection. The proposed technique can be used for such objects which CT or MRI cannot inspect due to restricted scan environment.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.12
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• pp.665-682
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• 2007

Line drawing is a widely used style in non-photorealistic rendering because it generates expressive descriptions of object shapes with a set of strokes. Although various techniques for line drawing of 3D objects have been developed, line drawing of 2D images has attracted little attention despite interesting applications, such as image stylization. This paper presents a robust and effective technique for generating line drawings from 2D images. The algorithm consists of three parts; filtering, linking, and stylization. In the filtering process, it constructs a likelihood function that estimates possible positions of lines in an image. In the linking process, line strokes are extracted from the likelihood function using clustering and graph search algorithms. In the stylization process, it generates various kinds of line drawings by applying curve fitting and texture mapping to the extracted line strokes. Experimental results demonstrate that the proposed technique can be applied to the various kinds of line drawings from 2D images with detail control.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.6
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• pp.465-470
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• 2013

In this paper, we introduce a modulation code design problem where best selection of two-dimensional codewords are determined to reduce two-dimensional (2D) Intersymbol Interference (ISI) and Interpage Interference (IPI), while when these codewords are randomly arranged on the storage, isolated pixel cannot be formed. Codeword selection problem and isolated pixel detection problem are formulated as integer program models and we develop a cutting plane algorithm where a valid cut is generated to remove current feasible solution to avoid isolated pixel by solving the isolated pixel detection subproblem. Using the proposed method, $4{\times}2$ 6/8 codewords with non-isolated pixel are found.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1330-1336
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• 2012

The Image retrieval has been study different approaches which are text-based, contents-based, area-based method and sub-image finding. The sub-image retrieval is to find a query image in the target one. In this paper, we propose a novel sub-image retrieval algorithm by Dot-Matrix method to be used in the bioinformatics. Dot-Matrix is a method to evaluate similarity between two sequences and we redefine the problem for retrieval of sub-image to the finding similarity of two images. For the approach, the 2 dimensional array of image converts a the vector which has gray-scale value. The 2 converted images align by dot-matrix and the result shows candidate sub-images. We used 10 images as target and 5 queries: duplicated, small scaled, and large scaled images included x-axes and y-axes scaled one for experiment.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.1
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• pp.77-82
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• 2004

In this paper we present a barcode reader to decode two-dimensional symbology PDF417 and propose a novel method to extract the bar-space Patterns directly from the gray-level barcode image, which employs the location and the distance between extreme points of each row or column of the barcode image. This algerian proves to be very robust from the high convolutional distortion environments such as defocussing and warping, even under badly illuminating condition. If the scanned barcode image is a result of the convolution of a Gaussian-shaped point spread function with a hi-level image, popular image segmentation methods such as image thresholding can not distinguish between very narrow bar-space patterns. The Proposed algorithm shows improved Performance over current barcode readers.

• The Transactions of the Korea Information Processing Society
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• v.4 no.9
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• pp.2173-2184
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• 1997

Among spatial queries handled in spatial database systems, nearest neighbor queries to find the nearest spatial object from the given locaion occur frequently. The number of searched nodes in an index must be minimized in order to increase the performance of nearest neighbor queries. An Existing approach considered only the processing of an nearest neighbor query in a two-dimensional search space and could not optimize the number of searched nodes accurately. In this paper, we propose the optimal search distance and prove its properties. The proposed optimal search distance is the measurement of a new search distance for accurately selecting the nodes which will be searched in processing nearest neighbor queries. We present an algorithm for processing the nearest neighbor query by applying the optimal search distance to R-trees and prove that the result of query processing is correcter than the existing approach.