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김평철(Pyung-Chul Kim),최환익(Hwan-Ik Choi),이윤준(Yoon-Joon Lee),이상호(Sang-Ho Lee),장윤석(Yun-Seog Jang),김명준(Myung-Joon Kim) 한국정보과학회 1991 정보과학회논문지 Vol.18 No.3
우리는 국가 행정 전산망에서 운영될 데이타베이스 관리 시스템의 하부구조로 사용될 수 있도록 다중 사용자를 지원하는 저장 시스템, MIDAS(Multiuser Index-based Data Access System)을 설계 구현하였다. MIDAS는 키를 통한 레코드 접근을 위해 B^+-트리를 관리하며, 보다 높은 수준의 레코드 검색을 위해 프리디키트를 검색 인자로 사용할 수 있도록 하였다. 대용량의 자료를 저장할 수 있도록 하기 위하여, 하나의 데이타베이스 및 화일이 여러 개의 디스크 볼륨에 걸쳐 저장될 수 있도록 하였다. 또한 공유 데이타베이스에 대한 순서화된 접근을 위하여 동시성 제어 기능을 제공한다. MIDAS의 설계, 구현에 사용된 기법들의 적합성을 입증하기 위해 잘 알려진 Wisconsin 벤치마크를 이용하여 WiSS및 Informix-Turbo와 성능을 비교하였다. 성능 시험 결과를 통해, MIDAS는 이미 사용되고 있는 다른 시스템과 비교할 만 하며, 데이타베이스 관리 시스템의 하부구조로 사용되었을 때, 성능상의 중대한 병목현상을 발생시키지 않을 것임을 알 수 있었다. We have built a multiuser storage system, named MIDAS (Multiuser Index-based Data Access System) which is intended to be used for a lower subsystem of database management systems. MIDAS provides B^+-tree indices for key-associative accesses to databases and predicates as search arguments for high level record scans. A database in MIDAS can have more than one disk volume and a file in a database can be spread over several volumes MIDAS supports concurrency control facility to serialize the accesses to shared databases. This paper addresses the results of a test on MIDAS which we have carried out by use of the Wisconsin benchmark and compares them with WISS and Informix-Turbo in order to verify the design and implementation rationales which we adopted. The test results show that MIDAS is a comparable storage system to existing ones and MIDAS is expected not to cause a performance bottleneck as a lower subsystem of database management systems.
제강분진을 이용한 4-Chlorophenol의 펜톤유사 산화반응
이웅 ( Lee Ung ),이성재 ( Lee Seong Jae ),박규홍 ( Park Gyu Hong ),배범한 ( Bae Beom Han ),장윤영 ( Jang Yun Yeong ),장윤석 ( Jang Yun Seog ) 한국물환경학회 2003 한국물환경학회지 Vol.19 No.4
The objective of this research was to investigate the role of steelers` dust as a catalytic reagent in H₂O₂/steelers` dust system. In acidic condition, FeO and Fe₂O₃ in steelers` dust could be dissociated to produce ferrous ion and ferric ion, which reacted with hydrogen peroxide to produce hydroxyl radicals and then degrade 4-chlorophenol. The batch experiments showed that 0.51 5mM 4-chlorophenol and its oxidation intermediates could be totally decomposed within 60 minutes by 1g/L steelers` dust and 0.485mM hydrogen peroxide at pH 2.7. The removal of 4-chlorophenol in H₂O₂/steelers` dust system was affected by the concentration of hydrogen peroxide rather than the dose of steelers` dust. The rate constants in the simplified kinetic model proposed in this study were estimated by fitting to the experimental data obtained in H₂O₂/steelers` dust system. Using the estimated kinetic rate constants, the simulation of 4-chlorophenol, ferrous iron, hydrogen peroxide, and hydroxyl radical concentration was performed. The predicted concentrations of 4-chlorophenol and hydrogen peroxide corresponded to the actual concentrations. The concentration of ferrous iron tended to be underestimated while that of hydroxyl radical was overestimated by the proposed model. For the experimental conditions conducted in this study, a value of 0.3mM hydroxyl radical could be suggested to calibrate the overestimated prediction.