• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.7-13
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• 2019

Role-based access or attribute-based access control in cloud environment or big data environment need requires a suitable mathematical structure to represent a hierarchical model. This paper define the notion of multipliers and simple multipliers of lattice implication algebras that can implement a hierarchical model of role-based or attribute-based access control, and prove every multiplier is simple multiplier. Also we research the relationship between multipliers and homomorphisms of a lattice implication algebra L, and prove that the lattice [0, u] is isomorphic to a lattice $[u^{\prime},1]$ for each $u{\in}L$ and that L is isomorphic to $[u,1]{\times}[u^{\prime},1]$ as lattice implication algebras for each $u{\in}L$ satisfying $u{\vee}u^{\prime}=1$.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.1
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• pp.14-19
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• 2002

• Magazine of the Korean Society of Agricultural Engineers
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• v.56 no.3
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• pp.10-16
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• 2014

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10a
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• pp.169-178
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• 1999

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2004.08a
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• pp.7-12
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• 2004

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2004.11a
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• pp.81-81
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• 2004

• Proceedings of the Korean Information Science Society Conference
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• 1998.10b
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• pp.99-101
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• 1998

대용량 공간 데이터를 포함하는 공간 데이터베이스에서 검색성능의 향상을 위해 공간 질의어가 최적화가 중요한 과제이다. 본 논문에서는 공간 데이터베이스에서 속성/공간 조건이 혼합된 질의에 적합한 질의 최적화 기법을 제시한다. 제안된 기법은 기존의 변환 규칙을 이용해서 대수 트리를 변환해 나가는 방법과는 달리 혼합된 질의어에 대한 질의 그래프로부터 동적 프로그래밍 기법으로 탐색 알고리즘을 실행함으로써 탐색 공간을 줄일 수 있고, 더욱 효율적으로 최소 비용의 실행 전략들 수립할 수 있다.

• Korean Journal of Logic
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• v.18 no.3
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• pp.437-456
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• 2015

This paper deals with Routley-Meyer semantics for two versions of R of Relevance. For this, first, we introduce two systems $R^t$, $R^T$ and their corresponding algebraic semantics. We next consider Routley-Meyer semantics for these systems.

• KCID journal
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• v.6 no.1
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• pp.39-47
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• 1999

One of the important features of a beach face is the dynamic response to the ever-changing waves and tides imposed from the body of water. Furthermore, human activities at or near the beach can enforce the characteristic changes on tidal motions and wave

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.39-50
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• 2004

GML proposed to offer interoperability of geography information is specifying various dynamic object schema for application in the wireless environment. These GML dynamic object schema supports the expression of moving objects that the position and shape change consecutively over time, so practical use of GML is increased in location-based service that provides various application services based on location information of moving objects. In particular, the conventional query languages about GML have been studied with priority given to the integration of geographic information, the support of spatial operations, and etc. However, it lacks the support for moving objects queries. Therefore, in this paper, we propose the moving objects query language that supports moving objects queries for GML documents by extension of XQuery that is standard in query language. Also, data model, algebra operation and various moving objects operators for the proposed query language are designed, and we apply the proposed query language to tornado government organization system to show that the proposed query language can be used effectively in various location-based service.