• Annual Conference of KIPS
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• 2002.11a
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• pp.241-244
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• 2002

컴퓨터와 정보기술 발달은 독립적인 e-비즈니스 솔루션들을 대거 등장하게 하고, 그로 인하여 분산 환경내 이종 시스템간의 원활한 정보의 공유와 황용을 위하여 동기화 필요성이 대두되고 있다. 이러한 독립된 플랫폼 상의 e-비즈니스 솔루션들간의 정보 공유를 위한 데이터 동기화는 중요한 문제이다. 따라서 본 논문에서는 각 e-비즈니스 프로세스들의 상호 운용성 보장과 분산처리 시스템 환경의 클라이언트/서버 구조의 문제를 해결할 수 있는 이동에이전트 시스템을 이용한 데이터 동기화를 언급한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.484-485
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• 2003

고전적인 Client/server환경에서의 통신은 Lan 환경하의 동기적 일대일 통신 기반 이였다. 그러나 인터넷이 확산되고 일반화되면서 많은 소프트웨어들은 Cluster 또는 Grid 같은 분산시스템 환경과 핸드폰, PDA 같은 Mobile환경에서 개발되고 있다. 이러한 환경은 WAN기반의 비동기적 일대다 다대다 통신을 기반으로 한다. 본 논문은 이러한 환경에 적합한 애플리케이션에 독립적이고 비동기 통신을 제공하며 각 통신요소(Event Supplier, Consumer)를 그룹으로 묶어 동적으로 관리해주는 기능을 제공하는 Event Channel Service를 제안한다. 이 Event Channel Service는 Event Channel을 사용하여 Event Supplier와 Consumer를 분리하며 Push. Pull 방식으로 Event를 전달할 수 있는 구조를 제공한다. 또한 다양한 Protocol을 지원하고 Quality of Service를 제공한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1134-1141
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• 2006

Java is platform-independent and supports uniform solutions from mobile area (J2ME) to enterprise area (J2EE), so Java is a good development tool for the environment of heterogeneous machines and distributed applications. Java applications need access control module as a Java package. In this paper, we design and implement it. Therefore Java developers can reduce development time, and system managers easily do access control work. Proposed module is based on Role-Based Access Control (RBAC) model and includes a Java package and administration tool.

• Journal of KIISE:Databases
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• v.37 no.4
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• pp.203-208
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• 2010

This paper deals with an efficient index scheduling technique based on Hilbert curve and MBR for k-NN query in a single wireless broadcast channel environment. Previous works have two major problems. One is that they need a long time to process queries due to the back-tracking problem. The other is that they have to download too many spatial data since they can not reduce search space rapidly. Our proposed method broadcasts spatial data based on Hilbert curve order where a distributed index table is also broadcast with each spatial data. Each entry of index table represents the MBR which groups spatial data. By predicting the unknown location of spatial data, our proposed index scheme allows mobile clients to remove unnecessary data and to reduce search space rapidly. As a result, our method gives the decreased tuning time and access latency.

• Journal of Information Processing Systems
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• v.3 no.2
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• pp.43-53
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• 2007

The use of agent paradigm in today's applications is hampered by the security concerns of agents and hosts alike. The agents require the presence of a secure and trusted execution environment; while hosts aim at preventing the execution of potentially malicious code. In general, hosts support the migration of agents through the provision of an agent server and managing the activities of arriving agents on the host. Numerous studies have been conducted to address the security concerns present in the mobile agent paradigm with a strong focus on the theoretical aspect of the problem. Various proposals in Intrusion Detection Systems aim at securing hosts in traditional client-server execution environments. The use of such proposals to address the security of agent hosts is not desirable since migrating agents typically execute on hosts as a separate thread of the agent server process. Agent servers are open to the execution of virtually any migrating agent; thus the intent or tasks of such agents cannot be known a priori. It is also conceivable that migrating agents may wish to hide their intentions from agent servers. In light of these observations, this work attempts to bridge the gap from theory to practice by analyzing the security mechanisms available in Aglet. We lay the foundation for implementation of application specific protocols dotted with access control, secured communication and ability to detect tampering of agent data. As agents exists in a distributed environment, our proposal also introduces a novel security framework to address the security concerns of hosts through collaboration and pattern matching even in the presence of differing views of the system. The introduced framework has been implemented on the Aglet platform and evaluated in terms of accuracy, false positive, and false negative rates along with its performance strain on the system.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.485-492
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• 2009

In the mobile service environment, patterns generated by temporal synchronization are streamed with different instance values. This paper proposed a variable clustering management method, which manages multiple data streaming dynamically, to support flexible clustering. The method manages synchronization effectively and differently with conventional streaming methods in data streaming environment and manages clustering streaming after the structural presentation level and the fitness presentation level. In the structural presentation level, the stream structure is presented using level matching and accumulation matching, and clustering management is carried out by the management of dynamic segment and static segment. The performance of the proposed method is tested by using k-means method, C/S server method, CDN method, and simulation. The test results showed that the proposed method has better performance than the other methods.

• Journal of Convergence for Information Technology
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• v.9 no.3
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• pp.22-29
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• 2019

Due to the development of ICT technology, convergence reality contents are utilized as technology for providing services in various industrial fields by visualizing various information such as sensor information and shared information in a service platform showing only simple three-dimensional contents. Research is underway to reduce the weight of applications by transmitting the resources of the object to be enhanced to the network as the information and the contents to be provided increase. In order to provide resources through the network, servers for processing various information such as pattern information, content information, and sensor information must be constructed in a cloud environment. However, in order to authenticate data transmitted and received in real-time in a cloud environment, there is a problem in that the processing is delayed and a delay phenomenon occurs in the rendering process and QoS is lowered. In this paper, we propose a system to distribute cloud server which provides augmented contents of convergent reality service that provides various contents such as sensor information and three - dimensional model, and shorten the processing time of reliable data through distributed relay between servers Respectively.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.6
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• pp.339-348
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• 2006

Recently, many researches on detecting and responding worms due to the fatal infrastructural damages explosively damaged by automated attack tools, particularly worms. Network service vulnerability exploiting worms have high propagation velocity, exhaust network bandwidth and even disrupt the Internet. Previous worm researches focused on signature-based approaches however these days, approaches based on behavioral features of worms are more highlighted because of their low false positive rate and the attainability of early detection. In this paper, we propose a Distributed Worm Detection Model based on packet marking. The proposed model detects Worm Cycle and Infection Chain among which the behavior features of worms. Moreover, it supports high scalability and feasibility because of its distributed reacting mechanism and low processing overhead. We virtually implement worm propagation environment and evaluate the effectiveness of detecting and responding worm propagation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.2894-2909
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• 2015

As the number of mobile devices such as smart phones and tablets explodes, the need for new services or applications is also rapidly increasing. Smart class application is one of the emerging applications, in which most of contents are distributed to all members of a class simultaneously. It is highly required to select relay nodes to cover shadow area of radio as well as extend coverage, but existing algorithms in a smart class environment suffer from high control packet overhead and delay for exchanging topology information among all pairs of nodes to select relay nodes. In addition, the relay selection procedure should be repeated in order to adapt to the dynamic topology changes caused by link status changes or device's movement. This paper proposes the learning based relay selection algorithm to overcome aforementioned problems. The key idea is that every node keeps track of its relay quality in a fully distributed manner, where RQI (Relay Quality Indicator) is newly defined to measure both the ability of receiving packets from content source and the ability of successfully relaying them to successors. The RQI of each node is updated whenever it receives or relays broadcast packet, and the node having the higher RQI is selected as a relay node in a distributed and run-time manner. Thus, the proposed algorithm not only removes the overhead for obtaining prior knowledge to select relay nodes, but also provides the adaptability to the dynamic topology changes. The network simulation and experimental results prove that the proposed algorithm provides efficient and reliable content distribution to all members in a smart class as well adaptability against network dynamics.

• The Journal of the Korea Contents Association
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• v.2 no.2
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• pp.36-41
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• 2002

In a mediator based information integration system that integrates information distributed on various data sources as a common data model, there are many researches on a common data mode providing a reservation of integrated data semantic, and on a resolution for a conflict caused by integrating various data modes. This paper proposes the DataBlender system that minimizes the semantic losses and provides an easy resolution for a conflict using the XML technology like as XML Schema, XQuery. Futhermore, it provides an integrated query facility usable in the mobile environment. So it becomes a foundation for a next Internet business environment.