• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.558-561
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• 2016

선로전환기는 분기기에서 철도의 궤도를 변경하는 핵심장치 중 하나로서, 해당 부품의 고장은 열차사고에 직접적인 영향을 미친다. 현재 철도 현장에서는 관리자가 모니터링 시스템을 통해 선로전환기의 장애 및 이상상황을 감시하고 지침서에 따라 관리를 수행한다. 본 논문에서는 실제 현장에서 발생하는 대규모의 선로전환기 이상상황 데이터를 대상으로 빅 데이터 해석학적 입장에서 심층 분석이 가능한 새로운 철도 유지보수 분석 시스템의 프로토타입을 제안한다. 제안하는 시스템은 첫째, 유지관리시스템에 저장된 선로전환기 데이터와 이상상황 데이터를 정규화하고 추출하여 베이스 테이블을 생성한다. 둘째, 베이스 테이블 상의 속성들을 스타 스키마로 설계하여 철도 유지보수 큐브로 구축한다. 마지막으로, 매핑된 철도 유지보수 큐브와 오라클에서 제공하는 AWM을 활용해 다차원적이고 심층적인 OLAP(On-Line Analytical Processing) 분석이 가능하다.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.683-685
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• 2010

Augmented reality is a technology for showing virtual objects overlapped with the real world as seen from the eyes of users. Studies are being conducted on effective communication methods using hand movements in augmented reality. Hand movements are an important means of human communication along with writing and voice. Space arrangement technology and hand tracking technology using markers to acquire virtual information in augmented reality have many limitations. This paper proposes tracking hand area for augmented object. The augmented objects change viewpoints by hand positions which improves the sense of three dimensions and immersion.