• Kyungpook Mathematical Journal
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• v.58 no.2
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• pp.203-219
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• 2018

This paper is devoted to the study of strongly ${\alpha}-semicommutative$ rings, a generalization of strongly semicommutative and ${\alpha}-rigid$ rings. Although the n-by-n upper triangular matrix ring over any ring with identity is not strongly ${\bar{\alpha}}-semicommutative$ for $n{\geq}2$, we show that a special subring of the upper triangular matrix ring over a reduced ring is strongly ${\bar{\alpha}}-semicommutative$ under some additional conditions. Moreover, it is shown that if R is strongly ${\alpha}-semicommutative$ with ${\alpha}(1)=1$ and S is a domain, then the Dorroh extension D of R by S is strongly ${\bar{\alpha}}-semicommutative$.

• Journal of Information Technology Services
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• v.6 no.2
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• pp.177-188
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• 2007

Policy-based Network Management (PBNM) has been presented as a paradigm for efficient and customizable management systems. The approach chosen is based on PBNM systems, which are a promising and novel approach to network management. These systems have the potential to improve the automation of network management processes. The Internet Engineering Task Force (IETF) has also used policy concepts and provided a framework to describe the concept as the Policy Core Information Model (PCIM) and its extensions. There are policy conflicts among the policies that are defined as the policy information model and they are not easily and effectively detected and resolved. In this paper, we present the brief description of PBNM and illustrate the concepts of policy core information model and its policy implementation for a network security. Especially we describe our framework for detecting and resolving the policy conflicts for network security.

• Annual Conference of KIPS
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• 2005.05a
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• pp.683-686
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• 2005

인터넷 비즈니스의 급성장에 따라 인터넷의 이용 및 의존도가 높아지고 인터넷 사용자나 인터넷 서비스 제공자(ISP) 모두 안정된 서비스를 요구하고 있다. 이와 함께 전산 시스템 관리와 장애 예방 등의 데이터 보호도 중요한 요소가 되었다. 운용인력은 변동이 없는 반면 시스템 수는 크게 증가하면서 시스템을 체계적이고 효율적으로 관리하고 언제 어디서나 시스템 성능을 모니터링하고 운용되는 애플리케이션을 제어하고자 하는 사용자들이 증가하였다. 본 논문에서는 모바일 환경 하에서 JMX(Java Management Extensions)[3]를 이용하여 분산된 자원과 서비스를 관리하는 원격 관리 시스템을 구현하고 원격지 터미널에 접속할 수 있는 MVTP(Mobile Virtual Terminal Protocol)을 구현하였다. 실험결과 시스템 관리자는 기존 메뉴기반 원격 관리 시스템에서 제공되지 않는 기능은 원격지 터미널에 접속 하여 관리할 수가 있고 모바일 단말기를 통해 시간, 장소에 구애 받지 않고 시스템을 안전하게 관리할 수 있었다.

• Annual Conference of KIPS
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• 2005.11a
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• pp.1267-1270
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• 2005

인터넷 비즈니스의 급성장에 따라 인터넷의 이용 및 의존도가 높아지고 인터넷 사용자나 인터넷 서비스 제공자(ISP) 모두 안정된 서비스를 요구하고 있다. 이와 함께 전산 시스템 관리와 장애 예방 등의 데이터 보호도 중요한 요소가 되었고 언제 어디서나 시스템 성능을 모니터링하고 운용되는 애플리케이션을 제어하고자 하는 사용자들이 증가하였다. 본 논문에서는 모바일 환경하에서 JMX(Java Management Extensions)를 이용하여 분산된 자원과 서비스를 관리하는 에이전트를 구현한다. 본 논문에서 제안하는 시스템을 통해 시스템 관리자는 자신의 모바일 단말기를 통해 시간, 장소에 구애 받지 않고 시스템을 안전하게 관리할 수 있다.

• Journal of Communications and Networks
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• v.16 no.6
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• pp.645-655
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• 2014

Latency, an identified element of Internet protocol (IP) mobility protocol execution, can reduce handover performance in mobile networks. Although the performance can be improved by applying an effective network-based IP mobility scheme in place of the traditional host-based alternatives, the existing inter-domain extensions of network-based IP mobility continue to suffer from an extended handover latency. This paper proposes a new inter-domain network-based IP mobility scheme based on node movement prediction. The proposed scheme accelerates the handover by preparing the future domain of the mobile node in a proactive manner. Analytical and simulation-based evaluations confirm improved performance of the proposed scheme in terms of handover latency and packet loss compared with existing schemes.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.12 no.4
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• pp.290-295
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• 2012

Due to importance of the concepts of ${\theta}$-closure and ${\delta}$-closure, it is natural to try for their extensions to fuzzy topological spaces. So, Ganguly and Saha introduced and investigated the concept of fuzzy ${\delta}$-closure by using the concept of quasi-coincidence in fuzzy topological spaces. In this paper, we will introduce the concept of ${\delta}$-closure in intuitionistic fuzzy topological spaces, which is a generalization of the ${\delta}$-closure by Ganguly and Saha.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.1
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• pp.41-48
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• 2007

Latest advances in network sensor technology and state of the art of mobile robot, and artificial intelligence research can be employed to develop autonomous and distributed monitoring systems. In this study, as the preliminary step for developing a multi-purpose "Intelligent Space" platform to implement advanced technologies easily to realize smart services to human. We will give an explanation for the ISpace system architecture designed and implemented in this study and a short review of existing techniques, since there exist several recent thorough books and review paper on this paper. Instead we will focus on the main results with relevance to the DIND data fusion with CI of Intelligent Space. We will conclude by discussing some possible future extensions of ISpace. It is first dealt with the general principle of the navigation and guidance architecture, then the detailed functions tracking multiple objects, human detection and motion assessment, with the results from the simulations run.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.1
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• pp.11-18
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• 2011

A mobile agent system is the most common software paradigm for distributed applications. A software development model to develop efficiently for these systems is needed. Unified Modeling Language (UML) is a widely used software development model to develop a system for Visualizing, Specifying, Constructing, Documenting. However, UML can not describe in explicit way the necessary mobility of the mobile agent-based software systems. In this paper, the interaction diagrams of UML (sequence diagrams and communication diagrams) are extended and used to express the mobility of the mobile agents in three ways. For a case study, we applied the extended diagrams to a distributed file searching using mobile agents, and showed these diagrams can describe the mobility very well.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.114-117
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• 2007

DES is an improvement of the algorithm Lucifer developed by IBM in the 1977. IBM, the National Security Agency (NSA) and the National Bureau of Standards (NBS now National Institute of Standards and Technology NIST) developed the DES algorithm. The DES has been extensively studied since its publication and is the most widely used symmetric algorithm in the world. But nowadays, Triple DES (TDES) is more widely used than DES especially in the application in case high level of data security is required. Even though TDES can be implemented based on standard algorithm, very high speed TDES codec performance is required to process when encrypted high resolution satellite image data is down-linked at high speed. In this paper, Intel SSE2 (Streaming SIMD (Single-Instruction Multiple-Data) Extensions 2 of Intel) is applied to TDES Decryption algorithm and proved its effectiveness in the processing time reduction by comparing the time consumed for two cases; original TDES Decryption and TDES Decryption with SSE2

• Journal of Ship and Ocean Technology
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• v.8 no.1
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• pp.10-30
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• 2004

High-fidelity RANS simulations are presented for a ducted marine propulsor, including verification ＆ validation (V＆V) using available experimental fluid dynamics (EFD) data. CFDSHIP-IOWA is used with $\textsc{k}-\omega$ turbulence model and extensions for relative rotating coordinate system and Chimera overset grids. The mesh interpolation code PEGASUS is used for the exchange of the flow information between the overset grids. Intervals V＆V for thrust, torque, and profile averaged radial velocity just downstream of rotor tip are reasonable in comparison with previous results. Flow pattern displays interaction and merging of tip-leakage and trailing edge vortices. In interaction region, multiple peaks and vorticity are smaller, whereas in merging region, better agreement with EFD. Tip-leakage vortex core position, size, circulation, and cavitation patterns for $\sigma=5$ also show a good agreement with EFD, although vortex core size is larger and circulation in interaction region is smaller.