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보안 실시간 데이터베이스 시스템을 위한 동시성 제어 기법
이순조,조숙경 서원대학교 응용과학연구소 2002 응용과학연구 Vol.11 No.1
In the Secure Real-Time Database System, it is essential not only correctness of result but also timeliness and security, in order to support successful transaction processing. Although the Bell-Lapadula model can remove the direct covert channel problem, means the exposure of the higher security data, it cannot remove the indirect covert channel problem by conflicts that are happened between different security clearance level transactions. It cannot satisfy the deadline of real-time transactions by considering securities of both data and transaction. With the low security prior scheduling policy, delaying the higher priority transaction in real-time database system can occur the priority inversion problem. In this thesis, a real-time transaction management method is proposed to remove the timing covert channel problem for efficient processing real-time transactions.
보안 실시간 데이터베이스 시스템에서 시간성 향상을 위한 동적 암호화 관리자에 관한 연구
이순조,Lee, Soon-Jo 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.1
대부분의 실시간 응용에서 보안은 또 하나의 중요한 요구 사항이 되고 있다. 따라서 보안 실시간 데이터베이스 시스템은 다양한 보안 등급을 갖는 여러 사용자가 공유하거나 악의를 갖은 해커에 의해 공격될 수 있는 민감한 정보를 관리해야 한다. 보안 실시간 데이터베이스 시스템이 보안을 위해서는 기존의 보안 방법뿐만 아니라 암호화 정책을 적용하는 것이 필요하다. 그렇지만 민감한 정보가 실시간 시스템에서도 보호되어야만 함에도 불구하고 보안 실시간 데이터베이스 시스템에서 암호화정책을 지원하기 위한 연구가 많지 않았다. 본 논문에서는 보안 실시간 데이터베이스 시스템의 이러한 암호화 정책 문제를 해결하기 위한 암호화 관리자를 제안한다. 보안 실시간 데이터베이스 시스템의 암호화 정책에서 중요한 것은 보안성과 시간성이다. 제안된 암호화 관리자의 중요한 특징은 트랜잭션 데드라인과 보안 수준을 고려하여 데이터를 동적으로 암호화하는 것이다. In many real-time applications, security is another important requirement, since the secure real time database system maintains sensitive information to be shared by multiple users with different levels of security clearance or to be attacked by hackers with ill will. Encryption policies are necessary for the security of secure real-time database systems in addition to the existing security methods, too. However, there has not been much work for the encryption policies in secure real-time database systems, although sensitive information must be safeguarded in real-time systems as well. In this paper, we propose a encryption manager for the purpose of solving the encryption policies of the secure real-time database systems. What is important in the encryption policies of secure real-time database systems is security and timeliness. A significant feature of the proposed encryption manager is the ability to dynamically adapt a encryption algorithm that consider transaction deadline and security level.
실시간 데이터베이스 시스템에서 시간성 향상을 위한 암호화정책
이순조 서원대학교 미래창조연구소 2004 과학과 문화 Vol.1 No.1
In order to secure real-time database systems, it is necessary to adapt encryption policy. What is important in the encryption policy of real-time database systems is security and transaction hit rate. However, there has been no study that tried to improve encryption policy considering real-time criteria. In this paper, we present encryption policy to support hard, firm, and soft real-time transaction. We also prove performance of the proposed policy through implementation and experiment.
이순조 서원대학교 응용과학연구소 2001 응용과학연구 Vol.10 No.1
In this paper, we propose a new scheduling method of real-time mobile transaction that has timing constraint by mobility of host. Our scheduling scheme use the queue based on priorities of transactions as a real-time mobile transaction scheduling method for enhancement of predictability and calculate the deadlines of transactions in consideration of constraints of real-time data. This method examines whether transaction can meet deadline or not, and then produces the best execution window for scheduling. Therefore, the proposed method prevents transaction restarts due to violation of constraint of real-time data, and maximizes the sum of the priorities of transactions that satisfy its deadline. The performance evaluation, is a comparison of traditional methods, shows that our scheduling method is improved from 20% to 30%
주기억장치 상주형 데이터베이스 시스템을 위한 실시간 질의 처리 기법
이순조 서원대학교 응용과학연구소 1999 응용과학연구 Vol.8 No.1
One of the major difficulties encountered in implementing a real-time database system is the long and often unpredictable disk access delay. One possible implementation approach to eliminate disk access delay from the database access is main memory databases, which maintain the database in main memory. To implement real-time main memory database system, query process and data structure should be designed to minimize memory access time and amount of memory space used. In this paper, we propose and implement the real-time query processing technique for main-memory resident database system. We adopt query transformation techniques to rewrite the parse tree. When query transforming, we prune the parse tree instead of making any execution plans to reduce optimization time and to avoid memory consuming. To execute transformed tree, we use lazy evaluation technique to minimize the amount of memory space used by temporary table and reduce memory access times. Our technique is implemented to real-time query processor for main-memory resident database systems.
실시간 주기억장치 데이터베이스 시스템을 위한 질의 최적화
이순조 서원대학교 응용과학연구소 2000 응용과학연구 Vol.9 No.1
This paper proposes query optimization method for real-time main-memory database systems. The proposed method is based on the pruning technique for the memory space and optimization time. For the memory access time, this method is adapted query modification and Lazy Evaluation technique. To evaluate that the proposed query optimization method can improve the system's performance, this method was compared with conventional methods.