• The Transactions of the Korea Information Processing Society
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• v.1 no.2
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• pp.163-171
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• 1994

The paper describes a design and implementation of a user interface system between a temporal database management system (DBMS) and a graphical display system. This interfacing system consists of a temporal DBMS, a graphical display system, and an interface control system. The temporal DBMS supports time and the graphical display system draws a graphic using an icon. The interfacing system shows the graphical animation with time factors by using a graphical knowledgeable. We describe how to interface them as well as the structure of temporal DBMS and graphical display system.

• Journal of KIISE:Databases
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• v.31 no.3
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• pp.243-251
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• 2004

Most programs of bioinformatics provide biochemists and biologists retrieve and analysis services of gene and protein database. As these services retrieve database for each arrival of user's request, it takes a long time and increases server's load and response time. In this paper. by utilizing database retrieval patterns of sequence alignment programs in bioinformatics, grouping method is proposed to share database retrieval between many requests. Carpool method is also proposed to reduce response time as well as to increase system expandability by combining new arriving requests with the previous on going requests. The performance of our two proposed schemes is verified by mathematic analysis and simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.214-216
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• 2002

시간에 따라 변화하는 사건을 기록하는 시간 데이타베이스에서는 사건을 저장할 때 시간 속성도 같이 저장한다. 최근에는 시간 데이타베이스의 속성을 고려하여 집지 함수와 같이 기존의 연산자를 확장하여 시간 데이타베이스에서 효율적으로 처리하려는 연구가 활발하게 진행되어 왔다. 사용자들은 종종 여러 애트리뷰트에 가중치를 두고 그 가중치 순서대로 결과가 보여지는 순위 질의를 실행한다. 기존의 순위 질의 개념을 그대로 시간 지인 데이타메이스에서 사용할 수 없다. 따라서 본 논문에서는 기존의 순위 질의에 시간 개념을 확장한 시간 순위 질의를 정의한다. 또한 시간 순위 질의 처리방법을 제 시 한다.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.1
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• pp.9-16
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• 2002

Join operation exert a great effect on the performance of system in temporal database as in the relational database. Especially, as for the temporal join, the optimization of interval partition decides the performance of query processing. In this paper, to improve the efficiency of parallel join query in temporal database. I proposed Minimum Interval Partition(MIP) scheme that time interval partitioning. The validity of this MIP algorithm that decides minimum breakpoint of the partition is proved by example scenario and I confirmed improved efficiency as compared with existing partition algorithm.

• Journal of KIISE:Databases
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• v.34 no.1
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• pp.84-97
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• 2007

Selectivity estimation techniques in query optimization have been used in commercial databases and histograms are popularly used for the selectivity estimation. Recently, the techniques for spatio-temporal databases have been restricted to existing temporal and spatial databases. In addition, the selectivity estimation techniques focused on time-series data such as moving objects. It is also impossible to estimate selectivity for range queries with a time interval. Therefore, we construct two histograms, CMH (current multidimensional histogram) and PMH (past multidimensional histogram), to estimate the selectivity of multidimensional sequence data in spatio-temporal databases and propose effective selectivity estimation methods using the histograms. Furthermore, we solve a problem about the range query using our proposed histograms. We evaluated the effectiveness of histograms for range queries with a time interval through various experimental results.

• Journal of KIISE:Databases
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• v.30 no.4
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• pp.372-380
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• 2003

Temporal databases support time-varying events so that conventional aggregate functions are extended to be processed with time for temporal aggregate functions. In the previous approach, it is done repeatedly to find time intervals and is calculated the result of each interval whenever target events are different. This paper proposes a method which processes temporal aggregate function queries using time point sequence. We can make time point sequence storing the start time and the end time of events in temporal databases in advance. It is also needed to update time point sequence due to insertion or deletion of events in temporal databases. Because time point sequence maintains the information of time intervals, it is more efficient than the previous approach when temporal aggregate function queries are continuously requested, which have different target events.

• Journal of KIISE:Databases
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• v.31 no.4
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• pp.373-383
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• 2004

There have been an emerging interests in the importance of database tuning techniques under modem database environments in which very large-scale data should be managed. In Particular. database performance parameters should be tuned to reflect system loads appropriately. This paper presents two parameter tuning strategies, namely throughput-based and response-time-based, which tune each performance parameter accordingly. The proposed techniques are applied to two commercial database systems in the TPC-W benchmark to see the effectiveness of those methods. The results show that they can help improve system performance considerably.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.873-882
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• 1998

The parallel database machine approach is currently widely and successfully used. There are four major architectures which are used in this approach: shared-nothing architecture, shared-evertying architecture, shared-disk architecture, and hybrid architecture. In this paper, we use an analytical model to evaluate the performance of these database machine architectures. We define an abstract model for each type of database machine design to obtain performance equatons describing the execution times with respect to the hybrid hash join poeration. Using the performance equations, we evaluate the execution times of the various database machine design models.

• The Journal of Natural Sciences
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• v.8 no.1
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• pp.109-114
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• 1995

For effective management of statistical database, statistical summary information must be provided by accessing directly the precomputed summary data from summary database to store and manage meta database for supporting statistical analysis and providing users with statistical summary information. In order to support effectively the use of summary database, we do the design and implementation of meta database and manager having a hierarchical structure as a data dictionary/directory and operation method is presented.

• Annual Conference on Human and Language Technology
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• 1995.10a
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• pp.131-136
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• 1995

최근들어 자연스럽게 필기된 한글을 인식함으로써 정보 입력 과정을 자동화하기 위한 오프라인 한글 글씨 인식에 관한 연구가 활발히 진행되고 있다. 오프라인 한글 글씨 인식에 관한 연구에 있어서 반드시 확보되어야 하는 연구 환경으로 대용량 오프라인 한글 글씨 데이타베이스의 구축을 들 수 있는데, 본 논문에서는 시스템공학연구소 국어공학센터의 국어 정보 베이스 개발사업의 일환으로 추진중인 오프라인 한글 글씨 데이타베이스의 구축현황에 대해 간략히 소개하고자 한다. 오프라인 한글 글씨 데이타베이스의 구축은 크게 글씨 데이타베이스 설계, 글씨 데이타 수집, 용지 스캔 및 문자 단위 분할, 데이타베이스 검증의 4 단계로 구성된다. 본 연구에서는 다양한 변형을 갖는 글씨체의 수집을 데이타베이스 구축시 가장 고려해야 할 요소로 삼았으며, 고품질의 일관성 있는 글씨 데이타베이스 구축을 위해 데이타베이스 설계 단계와 검증 단계에 많은 시간을 할애했다. 마지막으로 본 연구에서는 WWW(World Wide Web)의 HTML(Hyper Text Markup Language)을 이용하여 편리 한 사용자 인터페이스를 구현함으로써 사용자들이 쉽게 한글 글씨 영상을 검색 할 수 있음은 물론 인식 알고리즘의 개발에 사용 가능한 형태의 화일을 제공받을 수 있도록 구성하고 있다. 현재는 KS C 완성형 한글 2,350자 중에서 사용 빈도순 상위 520자에 대한 한글 글씨 1,000벌을 수집하여 명도영상 데이타베이스를 구축 중에 있으며, 향후 2년간 나머지 1,830자에 대한 한글 글씨 데이타를 수집하여 데이타베이스를 완성하고자 한다. 구축된 글씨 데이타베이스는 조만간 국내의 오프라인 한글 글씨 인식 연구자들에게 제공되어 우수한 인식 알고리즘의 개발을 위한 중요한 실험 데이타로서 사용될 예정이며, 개발된 인식 시스템에 대한 객관적인 성능 평가에 있어서도 크게 기여하여 국내의 오프라인 한글 글씨 인식에 관한 연구를 활성화시켜주는 계기가 될 것으로 기대된다.