• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.310-313
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• 2013

BitTorrent는 파일 공유를 위하여 가장 널리 사용되고 있는 P2P (Peer to Peer)프로토콜로서, Mesh-Pull 구조를 채용하여 라이브 스트리밍에 대한 연구가 꾸준히 이루어지고 있다. BitTorrent에서는 Peer Wire Protocol을 사용하여 피어들간에 파일조각들을 교환하게 되는데, 이를 위하여 주기적으로 버퍼맵 정보를 HAVE 메시지를 사용하여 브로드캐스트 하는데, 피어의 수가 증가할수록 이로 인한 시그널링 오버헤드가 크게 증가하는 문제를 갖고 있다. 본 논문에서는 이러한 문제를 극복하고 라이브 스트리밍의 성능을 개선하기 위하여 HAVE 메시지를 선택적으로 전송하는 방법을 제안한다. 실험을 통하여, 제안 방식은 기존의 BitTorrent 기반 Mesh-Pull 구조를 채용하는 라이브 스트리밍 방식과 비교하여 HAVE 메시지의 브로드캐스트로 인한 시그널링 오버헤드를 비약적으로 줄일 수 있음을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.421-425
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• 2006

본 논문에서는 TinyOS 기반의 센서 네트워크에 대한 리프로그래밍을 에너지 효율적으로 수행하기 위한 매커니즘을 제안한다. 베이스 스테이션에서 센서노드에게 프로그램 전체를 보내는 대신 이전 버전과의 차이인 델타를 생성해서 전송할 때 Multi-round Rsync 알고리즘을 적용해 델타 파일의 크기를 최대한 줄이는 기법과 업데이트가 불필요한 플래시메모리 페이지에 대한 업데이트를 방지하기 위한 페이지 맵 기법을 통해 Rsync만을 사용하는 기존 방식보다 최대 30% 이상 에너지를 절감할 수 있음을 확인하였다.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.804-818
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• 2004

As spatial data resources become more abundant, the potential for conflict among them increases. Those conflicts can exist between two or many spatial datasets covering the same area and categories. Therefore, it becomes increasingly important to be able to effectively relate these spatial data sources with others then create new spatial datasets with matching geometry and topology. One extensive spatial dataset is US Census Bureau's TIGER file, which includes census tracts, block groups, and blocks. At present, however, census maps often carry information that conflicts with municipally-maintained detailed spatial information. Therefore, in order to fully utilize census maps and their valuable demographic and economic information, the locational information of the census maps must be reconciled with the more accurate municipally-maintained reference maps and imagery. This paper formulates a conceptual framework and two map models of map conflation to make geometrically and topologically consistent source maps according to the reference maps. The first model is based on the cell model of map in which a map is a cell complex consisting of 0-cells, 1-cells, and 2-cells. The second map model is based on a different set of primitive objects that remain homeomorphic even after map generalization. A new hierarchical based map conflation is also presented to be incorporated with physical, logical, and mathematical boundary and to reduce the complexity and computational load. Map conflation principles with iteration are formulated and census maps are used as a conflation example. They consist of attribute embedding, find meaning node, cartographic 0-cell match, cartographic 1-cell match, and map transformation.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.1
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• pp.33-49
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• 2003

Recently, there have been large storage demands for manipulating multimedia data. To solve the tremendous storage demands, one of the major researches is the SAN(Storage Area Network) that provides the local file requests directly from shared-disk storage and also eliminates the server bottlenecks to performance and availability. SAN also improve the network latency and bandwidth through new channel interface like FC(Fibre Channel). But to manipulate the efficient storage network like SAN, traditional local file system and distributed file system are not adaptable and also are lack of researches in terms of a metadata structure for large-scale inode object such as file and directory. In this paper, we describe the architecture and design issues of our shared-disk file system and provide the efficient bitmap for providing the well-formed block allocation in each host, extent-based semi flat structure for storing large-scale file data, and two-phase directory structure of using Extendible Hashing. Also we describe a detailed algorithm for implementing the file system's device driver in Linux Kernel and compare our file system with the general file system like EXT2 and shard disk file system like GFS in terms of file creation, directory creation and I/O rate.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.673-678
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• 2012

Traditional culture's researcher has attempting to public use as a various method. Example is design of digital archive and digital contents. However, in spite of this effort, traditional culture's researcher has difficulty to public use. Because traditional culture is hard to understand, and less interest than the other area. Especially, traditional culture has not environment that user can searching and using the culture's information due to difficult to search the data and layers. We propose a design to make an ontology using information profile for digital contents of traditional culture. Also, we use topic-map for the factors of ontology's relation, and specify their relation using topic vector.

• Journal of KIISE:Databases
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• v.32 no.4
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• pp.362-371
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• 2005

Similarity indexing and searching are well known to be difficult in high-dimensional applications such as multimedia databases. Especially, they become more difficult when multiple features have to be indexed together. In this paper, we propose a novel indexing method called the GB-index that is designed to efficiently handle complex similarity queries as well as relevance feedback in high-dimensional image databases. In order to provide the flexibility in controlling multiple features and query objects, the GB-index treats each dimension independently The efficiency of the GB-index is realized by specialized bitmap indexing that represents all objects in a database as a set of bitmaps. Main contributions of the GB-index are three-fold: (1) It provides a novel way to index high-dimensional data; (2) It efficiently handles complex similarity queries; and (3) Disjunctive queries driven by relevance feedback are efficiently treated. Empirical results demonstrate that the GB-index achieves great speedups over the sequential scan and the VA-file.

• Journal of The Korean Association of Information Education
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• v.12 no.4
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• pp.405-415
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• 2008

In the existing curriculum of the Elementary Computer Education, it is hard to improve the CPS(Creative Problem Solving) skill and logical thought since the 7th national curriculum emphasizes application programs and CAI softwares. To complement this drawback, it is required to teach the principal of the computer science but there is not many researches for what problems of teaching computer science exist and what the response of students are. Thus, we carried out a research to know whether the students of elementary school can understand principal of computer science in the field of subject matter education. We found that the students can learn the principle of Saving Bitmap Image if the class level is adjusted properly.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.271-281
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• 2002

Currently, most web designers guarante high quality using bitmap graphics as fixed font size, but that has defects about file size and flexibility. Especially, to provide high quality of banner and advertise characters, after you should use a bitmap edit program, and then we should follow the method we add that program to HTML documents as bitmap data. In this study, as I show a couple of new tags in front of HTML documents, I show methods which can be presented diverse effects. When text information are stored, because we print out a screen with simple control points and outside information, it can be possible for us to express the same quality of Hangul characters like printed documents in a web browser. Regardless of the second class of platform, we can make it possible the character expression with exact character expressions and diverse effects.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.457-462
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• 2023

We proposed a flexible link configuration in a system combining mid-span spectral inversion (MSSI) and dispersion management used for long-distance transmission of high-capacity optical signals such as wavelength division multiplexing signals, and examined specific methods to increase chromatic dispersion and nonlinear distortion compensation effects. The dispersion map proposed to increase the flexibility of dispersion-managed link configuration has a 'random-inverse' structure. That is, in the proposed dispersion map, the residual dispersion per span (RDPS) of each fiber span in the first half section up to the optical phase conjugator is randomly distributed, and the RDPS distribution in the second half section reverses the distribution pattern of the first section. Although the proposed dispersion map has a random distribution of RDPS, it was confirmed that the distortion compensation effect is improved due to the fact that the dispersion profile is symmetrical with respect to the optical phase conjugator. In the dispersion map of the 'random-inverse' configuration, it was also confirmed that the compensation effect of the distorted wavelength division multiplexing signal becomes improved when the magnitude of the RDPS allocated to each fiber span is large.

• The Journal of Society for e-Business Studies
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• v.9 no.3
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• pp.79-94
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• 2004

W3C has developed the RDF standard for utilizing ontology in Web applications. This paper presents extracting, storing, and applying ontology on product data. The management and document information included in DWG files is focused as an example. By analyzing the relationship among the drawing data, the RDF schema is designed frist. Based on the schema ontology is extracted and stored in XML files. As an application of the stored ontology, we the schema ontology is extracted and stored in XML files. As an application of the stored ontology, we can reconfigure the sitemap of drawing data repositories. In this example, the users can select the view that he or she is interested in (e.g., designer, document, project). With such various views of an drawing data repository, the users can access the specific data more effectively.