• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.967-974
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• 1998

Access control scheme of the firewall systems protects the systems from threats by using the conventional discretionary access control mechanism. The discretionary access control mechanism is insufficient to control secure information flow on the multievel network. Thus, it is necessary to provide the mandatory access control mechanism to the firewall systems for the multilevel security environment. In this paper, we present a design scheme of the security mechanisms concerning the sensitivity label and the mandatory access control for securely processing the multilevel information.

• Review of KIISC
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• v.7 no.2
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• pp.85-94
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• 1997

This paper describes the notion of a Multilevel Secure Knowledge Base Management System(MLS/KBMS). It states a security policy and security constraints. A design for query operation introduced cover story in a MLS/KBMS is discussed. Query processing approach is to provide cover stories that lead to alternative explanations for readily available information. Therefore such cover stories prevent an unauthorized user from inferring high-level information from low-level data.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.4 no.2
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• pp.55-70
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• 1994

본 논문은 데이타베이스의 동적 기능을 모형화하기 위해서 동적 규칙을 사건과 동적 규칙 객체로 취급하여 개념적 스키마에 표현하는 동적 객체지향 데이타 모델을 제안한다. 제안된 모델에서 정적 구조와 동적 구조에 대한 개념들을 정의하고 모형화 과정에서 사용자의 이해도를 증진시키는 모델의 구성요호에 대한 그래픽 다이어그램을 제시하였다. 그리고 동적 규칙이 데이타베이스 구조에 포함됨으로써 발생가능한 정보의 불법적인 노출 또는 변경을 방지하기 위해서 BLP모델의 보안 정책을 확장하여 제안된 모델에 대한 11가지 종류의 다단계 보안 성질들을 정의하였다. 또한, 정의된 다단계 보안 성질들이 타당한가를 조사하기 위해서 패트리네트를 확장하여, 보안 성질의 검증작업을 수행하였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.8 no.3
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• pp.49-62
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• 1998

본 논문은 객체 모델링 기법을 이용하여 다단계 보안 데이터베이스 응용에 대한 구조적 특징을 표현하기 위한 모델을 제시한다. 즉, 응용 영역에 대한 데이터와 보안 의미르 통합한다. 이는 응용 영역의 데이터에 대한 불법적 유출이나 수정을 방지하는 도구가 된다 . 개발한 도구를 기초로 한 구현 모델에서는 다단계 데이터베이스를 단일 보안등급 데이터베이스들로 분해한다. 인스턴스뿐만 아니라 스키마도 보호하며 속성값 다중 인스턴스화 기법을 이용하여 커버 스토리를 표현한다. 그리고 그 모델에서의 생성, 검색, 삭제, 그리고 갱신과 같은 연산 의미를 설명한다.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.735-738
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• 2000

The most important issue in database security is correct concurrency control under the restrictive security policy. The goal of secure transaction management is to keep security and provide many concurrent users with the high availability of database. In this paper, we consider the security environment of multidatabase system with replicated data. The read-from relationship in the existed serializability is improper in security environment. So, we define new read-from relationship and propose new secure 1-copy quasi-seriailzability by utilizing this relationship and display some examples. This security environment requires both the existed local autonomy and the security autonomy as newly defined restriction. To solve covert channel problem is the most difficult issue in developing secure scheduling scheme. The proposed secure 1-copy quasi-serializability is very proper for global transactions in that this serializability not violates security autonomy and prevents covert channel between global transactions.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.6 no.1
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• pp.61-82
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• 1996

데이타베이스 시스템의 다단계 보안을 위해 비밀 채널의 제거는 필수적인 것이다. 본 논문은 비밀채널<8>을 제거하고 성능향상을 위해 보안 2버전 2단계 로킹을 제안한다. 보안 2버전 2단계 로킹은 기본 2PL에 부가적으로 2개의 버전과 보안 요소를 고려한 것이다. 즉, 상위등급 트랜잭션 판독과 하위등급 트랜잭션 기록 사이의 충돌을 피하고 상위등급 판독연산과 동일등급 사이의 성능을 향상시키기 위한 방법이다. 기존의 보안 2단계 로킹기법과는 달리 2개 버전의 데이타와 희사기법을 사용하여, 데이타의 신선도가 떨어지지 않으면서 성능의 향상을 얻을 수 있게 한다.

• Korean Journal of Health Education and Promotion
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• v.30 no.1
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• pp.53-64
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• 2013

Objectives: In this study, a multilevel analysis model has been designed to investigate the effect of personal characteristics associated with smoking cessation on anti-smoking determinants with a goal of finding out the factors which have influence on smoking cessation among the entrants of smoking cessation clinic in a public health center. Methods: A total of 253,136 male smokers who received smoking cessation services for more than six(6) months in a smoking cessation clinic of public health center from July 16, 2007 to July 15, 2008 were examined. For technical analysis, SPSS Version 2.0 has been used. For multilevel analysis on smoking cessation determinants, in addition, HLM 7.0 has been adopted. Results: According to the unconditional model of multilevel analysis, the success rates of smoking cessation among the entrants of a smoking cessation clinic were 47.3%. In an unconditional slope model test to which regional variables were added, a negative effect was observed in average smoking amount, total smoking period, nicotine dependence and services while a positive effect was found in age, stress and type of social security in terms of the log of the odds of smoking cessation. In a conditional model test, a positive effect was observed in Non-Smoking Campaigns (NSC) and Frequency of Counseling (FC) in terms of the log of the odds of smoking cessation in regional variables. Conclusions: It is important to approach smokers individually and, at the same time, build healthy environment for a local community to increase smoking cessation rates among the entrants of smoking cessation clinic in a public health center.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.51-59
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• 2009

Many failures are due to incorrectly programmed transactions and data entry errors. System failure causes the loss or corruption of the contents of volatile storage. Although global processing protects data values to detect direct or indirect information effluence, security environments are very important in the recovery management of heterogeneous systems. Although transaction can't control system fault, the restart for the system can cause information effluence by low bandwith. From various faults, it is not easy to maintain the consistency and security of data. This paper proposes recovery management protocols to assure global multilevel secure one-copy quasi-serializability in security environments of heterogeneous systems with replicated data and proves its correctness. The proposed secure protocols guarantee the reliability and security of system when the system fault is happened.

• Electronics and Telecommunications Trends
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• v.5 no.3
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• pp.71-89
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• 1990

Secure/Trusted 컴퓨터시스템을 설계 및 개발하기 위하여 필요한 보안정책과 이를 실현하기 위한 보안모델을 분석하였다. 보안정책으로는 TCSEC을 근간으로 하여 전통적인 MAC정책과 DAC 정책을 상호 비교분석하였으며, 보안 모델로는 미국방성 산하의 NCSC의 Multilevel Security를 만족하는 BLP 모델을 비롯하여 Biba모델, HRU모델, SRI모델, Lattice모델들의 비교분석을 제시하였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.3
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• pp.117-128
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• 1997

When computer systems with mandatory access control mechanism are interconnected each other for enforcing the MHS(Message Handling System) security on the multilevel secure distributed network environment, illegal information flow may occurs due to the unexpected cascade vulnerability problem. In this paper, new MHS security policy and security property functions are proposed for preventing the cascade vulnerability.