• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.1
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• pp.40-47
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• 2009

Recently, dynamic proxy caching has been proposed on the distributed environment so that media objects by user's requests can be served directly from the proxy without contacting the server. However, it makes caching challenging due to multimedia large sizes, low latency and continuous streaming demands of media objects. To solve the problems caused by streaming demands of media objects, this paper has been proposed the grouping scheme with fuzzy filtering based on partition and mapping. For partition and mapping, this paper divides media block segments into fixed partition reference block(R$_f$P) and variable partition reference block(R$_v$P). For semantic relationship, it makes fuzzy relationship to performs according to the fixed partition temporal synchronization(T$_f$) and variable partition temporal synchronization(T$_v$). Simulation results show that the proposed scheme makes streaming service efficiently with a high average request response time rate and cache hit rate and with a low delayed startup ratio compared with other schemes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1696-1704
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• 2008

The conventional hard disk has been the dominant database storage system for over 25 years. Recently, hybrid systems which incorporate the advantages of flash memory into the conventional hard disks are considered to be the next dominant storage systems. Their features are satisfying the requirements like enhanced data I/O, energy consumption and reduced boot time, and they are sufficient to hybrid storage systems as major database storages. However, we need to improve traditional index management schemes based on B-Tree due to the relatively slow characteristics of hard disk operations, as compared to flashmemory. In order to achieve this goal, we propose a new index management scheme called FNC-Tree. FNC-Tree-based index management enhanced search and update performance by caching data objects in unused free area of flash leaf nodes to reduce slow hard disk I/Os in index access processes. Based on the results of the performance evaluation, we conclude that our scheme outperforms the traditional index management schemes.

• Journal of KIISE:Databases
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• v.30 no.4
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• pp.408-419
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• 2003

Data warehouses are usually dedicated to the processing of quires issued by decision support system(DSS). The response time of DSS queries is typically several orders of magnitude higher than the one of OLTP queries. Since DSS queries are often submitted interactively, techniques for reducing their response time are important. The caching of query results is one such technique particularly well suited to the DSS environment. In this paper, we present a cache manager for such an environment. Specifically, we define a canonical form of query. The cache manager looks up a query based on the exact query match or using a suggested query split process if the query is found is non-canonical form or in canonical form, respectively. It dynamically maintains the cache content by employing a profit function which reflects in an integrated manner the query execution cost, the size of query result, the reference rate, the maintenance cost of each result due to updates of their base tables, and the frequency of such updates. We performed the experimental evaluation and it positively shows the performance benefit of our cache manager.

• Journal of Korea Multimedia Society
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• v.11 no.7
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• pp.914-927
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• 2008

Grid database management systems are used for large data processing, high availability and data integration in grid computing. Furthermore the grid database management systems are in the use of manipulating the queries that are sent to distributed nodes for efficient query processing. However, when the query processing is concentrated in a random node, it will be occurred with imbalance workload and decreased query processing. In this paper we propose a load balancing method for query processing based on cache Management in grid databases. This proposed method focuses on managing a cache in nodes by cache manager. The cache manager connects a node to area group and then the cache manager maintains a cached meta information in node. A node is used for caching the efficient meta information which is propagated to other node using cache manager. The workload of node is distributed by using caching meta information of node. This paper shows that there is an obvious improvement compared with existing methods, through adopting the proposed algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.7
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• pp.837-844
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• 2019

As the demand for video streaming has been rapidly increasing recently, video streaming schemes for increasing the efficiency of radio resource has attracted a lot of attention. In this paper, we propose an adaptive video streaming scheme to enhance the efficiency of video streaming by using receivers' caching capability. The proposed streaming scheme can transmit video data on a broadcast basis even when two clients request different video data, only if specific conditions satisfied, while existing schemes can only transmit video data on a broadcast basis only when two clients request the same video data. In this paper, we mathematically derive the average transmission time of the proposed scheme and the approximation of the average transmission time. The accuracy of the mathematical analysis is verified by simulations. Mathematical analysis and simulation results show that the proposed scheme can significantly reduce the average transmission time, compared to the existing scheme.

• Journal of Convergence for Information Technology
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• v.12 no.1
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• pp.7-14
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• 2022

Unlike general maps, the underground geospatial Information is a system made to view underground information in a 3D shape. This system is managed by a tile maps to lighten the data. But there are various underground structures in the basement, and the structures are made of 3D data, so the data size is large. Therefore, when a client mobile program requests a tile map, the service server fetches the requested tile map from the DB server and transmits ti to the client, but there is a transmission delay time problem. In this paper, we design the tile cache method to improve the request response speed for the tile map data provided to the client in the mobile underground geospatial information system. We propose a method in which a service server predicts and prefetchs the next tile map while the client is viewing tile map, and stores the prefetching data in the memory of client mobile terminal. Then, the transmission delay time problem can be solved.

• Annual Conference on Human and Language Technology
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• 1992.10a
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• pp.367-375
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• 1992

한국어는 다른 언어와는 달리 초성, 중성, 종성의 자소가 모여서 한 음절을 이룬다. 음절을 이루는 자소는 그 발생의 확률적 성질에 따라 확률변수로 간주된다. 음절 안에서 자소간의 발생의 상관관계는 자소간 조건부 확률 및 엔트로피로 표시된다. 음절이 모여서 단어를 이루고 단어를 이루는 음절은 그 발생의 확률적 성질에 따라 확률변수로 간주된다. 한국어 단어안에서 음절간의 발생의 상관관계는 음절간 조건부 확률 및 엔트로피로 표시된다. 수 있다. 그런데 가능한 음절의 종류가 매우 많기 때문에 음절 발생의 상관관계를 표시하는 지표로서 음절간 조건부 확률 대신 초성, 중성, 종성 단위의 조건부 확률을 사용하는 것이 음절간의 발생의 상관관계를 표시하는데 효과적이다. 이러한 한국어의 정보이론적 연구를 위하여서는 기초자료로서 한국어 단어의 빈도분포가 필요하다. 한국어 단어의 빈도분포의 포괄적인 조사는 1956년의 "우리말 말수 사용의 잦기 조사"가 유일한 실정이다. 시간 경과에 따른 한국어의 정보이론적 특성 변화의 분석을 위하여서는 한국어 단어 빈도의 주기적인 조사가 필요하다. 한국어에서 초성, 중성, 종성단위의 정보이론적 연구결과는 한국어 음성인식 및 함성, 자연언어처리, 암호법, 언어학, 음성학, 한국어부호 표준화 연구등에 이용될 것으로 기대된다. 남북한의 언어는 분단이 지속됨에 따라 상호 이질화가 진행되고 있다. 이러한 이질화를 극복하려는 부분적인 노력으로 남북한 언어의 한국어 영문표기의 단일화 등이 있었다. 이러한 노력에 병행하여 남한과 북한의 언어에 대한 정보이론적 비교 연구도 있어야 할 것이다. 정보를 효과적으로 캐싱할 수 있도록 인접한 데이터를 클러스터링해서 브로드캐스팅하여 이동 호스트의 구성 시간(setup time)을 최소화하였다. 그리고, 맨하탄거리(Manhattan Distance)를 사용해서 위치 의존 질의에서 사용하는 데이타를 캐싱하고 질의를 처리하는 방법을 제안한다. 맨하탄 거리를 이용해서 캐싱하면 도로에 인접해서 위치한 데이타를 효과적으로 캐싱할 수 있다. 또한, 거리 계산 방법으로 맨하탄 거리를 사용하면 도심에서 실제 이동 거리와 비슷한 값을 알 수 있고, 직선 거리 계산식에 비해서 계산식도 간단하기 때문에 시스템 계산량도 줄일 수 있다. 기준으로 라이신 부산물은 어분 단백질을 40%까지 대체가 가능하였으며, 아울러 높은 라이신 부산물의 대체 수준에 있어서 사료효율과 단백질 전환효율을 고려한다면 아미노산 첨가(라이신과 아르지닌)와 중화 효과에 좋은 결과가 있을 것으로 사료된다.의한 적정 양성수용밀도는 각고 5~6cm 크기의 경우 10~15개체가 적합하였다. 수증별 성장은 15~20 m 수층에서 빨랐으며, 성장촉진과 폐사를 줄이기 위해서는 고수온이 지속되는 7~10월에는 20~30m수층으로 채롱을 내려 양성하고 그 외 시기에는 15 m층 내외가 좋은 것으로 나타났다. 상품으로 출하 가능한 크기 인 각고 10 cm이상, 전중량 140 g 내외로 성장시 키기까지는 채묘후 22개월이 소요되었고, 출하시기는 전중량 증가가 최대에 이르는 3월에서 4월 중순이 경제적일 것으로 판단된다.er 90 % of good relative dynamic modulus of elasticity due

• Journal of KIISE:Information Networking
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• v.27 no.3
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• pp.301-314
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• 2000

As the number of World Wide Web (Web) users grows, Web traffic continues to increase at an exponential rate. Currently, Web traffic is one of the major components of Internet traffic. Also, high bandwodth usage due to Web traffic is observed during peak periods while leaving bandwidth usage idle during off-peak periods. One of the solutions to reduce Web traffic and speed up Web access is through the use of Web caching. Unfortunately, Web caching has limitations for reducing network bandwidth usage during peak periods. In this paper, we focus our attention on the use of a prefetching algorithm for reducing bandwidth during peak periods by using off-peak period bandwidth. We propose a statistical, batch, proxy-side prefetching scheme that improves cache hit rate while only requiring a small amount of storage. Web objects that were accessed many times in previous 24 hours but would be expired in the next 24 hours, are selected and prefetched in our scheme. We present simulation results based on Web proxy and show that this prefetching algorithm can reduce peak time bandwidth using off-peak bandwidth.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.379-382
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• 2003

본 논문에서는 멀티미디어 웹 서버에 나타나는 통신량을 추적하여 사용자의 액세스 패턴을 분석하고 그에 따른 캐싱 모델을 수립하였다. 적중률과 바이트적중률을 동시에 향상시키기 위한 파일 타입 캐시 정책을 제안하였으며, 성능을 평가한 결과 캐시의 유용성을 개선하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.398-398
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• 2004