• Journal of the Korea Computer Industry Society
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• v.3 no.7
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• pp.921-926
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• 2002

B+-Tree is the most popular indexing method in DBMS to manage large size data in more efficiency. However the existing B+-Tree has shortcomings in there is overhead on DISK/IO when the first time of constructing DB or of making Index, and it lessens the concurrency if there are frequent delete operations so that the index structure also should be changed frequently. To solve these problems almost DBMS is using batch construction method and lazy deletion method. But to apply B+-Tree, which is using batch construction method and lazy deletion method, into DBMS the technique for controlling and recovering concurrency is necessary, but its researching is still unsatisfactory so that there is a problem on applying it into actual systems. On this paper I suggest the technique for controlling and recovering concurrency how to implement the batch construction method and the lazy deletion method in actual DBMS. Through the suggested technique there is no cascade rollback by using Pending list, it enhances the concurrency by enabling insertion and deletion for base table on every reconstruction, and it shortens transaction response time for user by using system queue which makes the batch constructing operation is processed not in user's transaction level but in system transaction level.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.951-959
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• 2001

Video database has the function that stores videos and retrieves the video informations for the service request of users. Therefore, the purpose of the video database is to provide not only an environment both convenient and efficient for retrieving and storing video, but also to serve the requested video informations with rapid startup latency for more users. But, some users of video database as VOD application might tolerate slow startup latency because they would watch video during one hour or two hours. In this paper, we propose the novel policy of the storage system of video database, which serves efficiently the users by considering the classes of the users in video database. The policy admits the random movements of disk heads for urgent user classes but maintains the sequential or restricted movements of disk heads for less-urgent user classes like VOD application in storage system of video database. So, it can not provide only rapid startup latencies for urgent requests but also it can process more service requests in all.

• The KIPS Transactions:PartD
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• v.16D no.6
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• pp.835-844
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• 2009

Today, most of all the query processors in the world generally use the 'Pipelining' method to acquire fast response time (first record latency) and less memory usage. Each of the operator nodes in the Query Execution Plan (QEP) provides Open(), Next(), and Close() functions for their interface to facilitate the iterator mechanism. However, the embedded database systems for the mobile devices, based on the FLASH memory, usually require a function like Previous(), which returns the previous records from current position. It is because that, in the embedded environment, the mobile devices cannot fully provide it main memory to store all the query results. So, whenever needed the previously read records the user (program) should re-fetch the previous records using the Previous() function: the BACKWARD data fetch. In this paper, I introduce the 'Direction Switching Problem' caused by the Previous() function and suggest 'Block-wise Skipping' method to fully utilize the benefits of the block-based data transfer mechanism, which is widely accepted by most of the today's relational database management systems.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.3 s.303
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• pp.9-16
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• 2005

For designing the database more efficiently, normailzation can be enforced to minimize the degree of unnecessary data redundancy and contribute to enhance data integrity. However, deep normalization tends to provoke multiple way of schema join, which could then induces response time degradation. To mitigate this sort of side effect that the normalization could brought, a number of field studies we observed adopted the idea of denormalization. To measure whether denormalization contributes to response time improvement, we in this paper developed two different data models about customer service system, one with perfect normalization and the other with denormalization, and evaluated their query response time behaviors. Performance results show that normalization case consistently outperforms denormalization case in terms of response time. This study show that the idea of denormalization, quite rarely contributes to that sort of improvement due ironically to the unnecessary data redundancy.

• Asia pacific journal of information systems
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• v.7 no.3
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• pp.23-37
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• 1997

Although numerous models and solution algorithms to design efficient distributed databases have been developed, very few have been validated for their effectiveness. In this paper, we develop a simulation system which can be used to analyze and validate the average response time of distributed database designs. Our simulation system models comprehensive query processing strategies such as semijoin as well as a concurrency control mechanism We analyze and validate an average response time distributed database design model using our simulation system.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.22 no.4
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• pp.6-14
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• 2004

정보검색 기술은 거의 40년 전부터 미국 코넬대학의 Salton과 영국 케임브리지 대학의 van Rijsjbergen 및 Sparck Jones 등 초창기 선구자들을 중심으로 기초가 세워지고 ACM에서는 약 30년 전에 SIC(Special Interest Group)로 인정 받은 후 독립된 학문 분야로 꾸준히 발전되어 왔다. 1968년에 출간된 Salton의 책 [1]에서는 정보검색을 "정보의 구조, 분석, 조직, 저장, 탐색(searching), 검색(retrieval)에 관한 분야"로 정의하고 데이터베이스 시스템과 질의응답 시스템도 포함시키고 있다. 포함시키고 있다.

• Digital Contents
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• no.5 s.108
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• pp.90-95
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• 2002

지난 호에서는 정적 SQL(Static SQL)의 장점과 Oracle8i에서 도입된 analytic function이라는 새로운 기능을 이용해서 부분범위처리가 가능한 효율적인 게시판 구현에 대해서 살펴보았다. 이번 호에서는 analytic function, FBI(Function Based Index), 순환관계(connect by ㆍㆍㆍstart with)를 이용한 응답글(속칭 리플)이 있는 게시판의 부분범위처리에 대해서 살펴보고, 게시판의 총글수나 사용자별 마일리지합 정보 등 집계성이나 항상 사용자가 온라인상에 보고자하는 정보들을 효율적으로 관리하기 위해 materialized view를 적용하는 방법에 대해서 알아보겠다.

• Digital Contents
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• no.8 s.159
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• pp.86-88
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• 2006

이 내용은 문화광광부의‘ 2005문화산업통계’를 인용하여 작성한 내용으로 1부와 2부로 나누어 분석했다. 1부에서는 조사대상 213개 애니메이션업체 중 152개업체의 응답 및 조사를 통해 만들어진 자료를 바탕으로 크게 애니메이션업계의 일반현황과 매출액현황으로 구분했다. 일반현황은 설립연도현황, 제작비용내역현황, 지적재산권 등이며 매출액현황은 사업형태별, 지역별, 매출규모별, 종사자규모별, 수입, 수출별등 다양한 관점에서 조사된 통계내용이다. 따라서 제시된 각 항목의 통계를 통해 특징을 분석하고 이를 통해 애니메이션 산업의 발전을 위한 제안을 모색해 보고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.1535-1538
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• 2003

웹 상의 데이터 교환 표준으로 XML이 등장한 이래 XML 데이터를 관계 DBMS에 저장하고 질의 처리를 수행하는 기법에 관한 연구가 활발히 수행되고 있다. 전통적인 데이터베이스에서처럼 단일 또는 복수개의 XML문서에 대한 XML 질의를 통해 XML 뷰를 정의할 수 있고 이는 질의 처리 성능 향상을 위해 웹 환경에서 실체화될 수 있다. 본 논문에서는 XML 데이터를 관계 DBMS에 저장하였을 때 XML 질의의 결과를 실체뷰로 캐쉬하였다가 동일 질의가 반복될 때 캐쉬를 이용한 응답을 수행하기 위한 XML 뷰 실체화 모델을 세 가지 제시하고 비교, 평가한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.204-209
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• 1998

OMG에서 제안된 CORBA는 표준 개방 분산환경의 플래트폼을 제공하며 객체지향적인 방법으로 최근 주목을 받고 있다. 일반적으로 CORBA는 원격 데이터베이스 질의 등과 같은 요구/응답형의 응용에 잘 적용이 된다. 그러나 과도한 처리부담, 실시간 처리 기능과 QOS 지원 등의 결여로 멀티미디어 스트림과 같은 연속미디어의 처리에는 부적합하다. 본 논문에서는 실시간 제약을 갖는 멀티미디어 스트림의 효율적인 전송을 위하여 기존의 CORBA를 확장하여 멀티미디어 서비스를 설계한다.