• Journal of Korea Multimedia Society
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• v.8 no.9
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• pp.1153-1162
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• 2005

In this paper, we developed an XML Document Data Synchronization System for java(XDS4j) based on both SyncML(Synchronization Markup Language) framework Sync4j and embedded database system Berkeley DB XML. Because most existing data synchronization systems are based on file systems, data synchronization times at Fast Sync in those systems are very delayed. In the XDS4j, however, XML documents data produced at SyncML client and SyncML server are managed by embedded database system, and also synchronization time at Fast Sync is reduced because only partial elements are accessed by applying to XPath.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.253-256
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• 2009

Synchronization system which applies to two-way synchronization of spatio-temporal in the mobile environment maintains a consistence of DB from some defect during synchronization. This study analyzes defects that are generated at the mobile client-server environment and proposes recovery protocol which can rerun consistence of DB and synchronization.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2007.05a
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• pp.75-83
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• 2007

본 논문에서는 .NET 기반의 Remoting 시스템과 Socket 통신을 이용하여 이 기종 DB Server 간의 Data 동기화를 구현하였다. 이 시스템은 Client 의 웹 브라우저를 이용 Socket 통신으로 Data를 전송하여 데이터베이스에 저장하는 방식으로 구현하였고, Data 읽기는 Remoting 기술인 중계 어플리케이션 서버의 클래스를 원격으로 실행시켜 Data를 가져오는 방식으로 구현하였다. DB 동기화는 Data를 저장할 때 중계 어플리케이션 서버와 DB 서버의 Data 관리 어플리케이션 간 비동기 통신으로 DB 서버의 Data 처리 수준을 실시간으로 감시하여 중계 어플리케이션 서버에서 선택적으로 Data를 전송하고, 이후 Data 처리 수준이 정상화기 되면 다시 Data를 전송케 함으로써 이 기종 DB 서버간의 동기화를 구현하였다. 본 논문은 1 장에 서론, 2 장에 .NET Remoting 기술과 네트워크 프로그래밍, 3 장에 이 기종 DB 서버 간 동기화 시스템 설계 및 구현, 4 장에 결론을 기술하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.183-186
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• 2008

In ubiquitous GIS system, the spatial information could be updated and utilied by mobile terminals. Spatial information stored in mobile terminals should be able to synchronize to the server. However, in mobile environment, there are some limitations in synchronization service due to the limited bandwidth. The ActMAP system, that was developed to consider of mobile environment, has suggested a partial update protocal for synchronization in order to solve the narrow bandwidth problem. But it is still has a problem that it does not consider two-way synchronization between a server and a mobile terminal. This paper suggests a two-way synchronization protocol between a server and mobile terminals. It, therefore, is inclined to supporting updated and utilization of spatial information using mobile terminals.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.382-384
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• 2003

IMF 이후 기업들은 구조조정을 통한 체질개선에 총력을 기울임과 동시에 그 동안의 외형적 성장에서 탈피하여 투자 자본의 효율 향상을 위해 기업가치를 극대화하려고 노력하고 있다. 따라서. 각 사업체의 중점 육성 부분과 매각 부분을 선별하게 되었으며, 이해 사 간의 인수 합병이 빈번히 일어나고 있다. 그러나, 이렇게 생성된 기업체의 경우, 기존 전산 시스템의 하드웨어, 소프트웨어, 데이터베이스 등의 불일치로 통합에 많은 시간과 비용이 발생하고 있다. 따라서, 본 논문에서는 기존 전산 시스템의 플랫폼 불일치를 극복하며, 기존 시스템으로부터 개발되는 새로운 시스템으로의 전이를 자연스럽게 해줄 플랫폼 독립적인 대용량 데이터 동기화 서버(SyncDB2DB)를 설계한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.1
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• pp.77-87
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• 2008

Recently, many hash-based authentication protocols were presented to guarantee mutual authentication between tag and DB in RFID system. To be suitable for distributed DB environment, one generally uses fixed constant value as a tag ID. However, some existing protocols have security flaws or heavy computational loads in DB in order to search a tag ID. We propose a secure authentication protocol which is suitable for distributed DB environment by using unchangeable tag ID. The storage method of pre-synchronized information in DB at previous session is core idea of our proposal which gives low-cost ID search of DB at next session. In normal synchronization state, our protocol only requires 3 hash operations in tag and DB respectively.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.15-24
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• 2004

Electronic commerce is widely used with the development of information communication technologies in internet using public key certificates. And the study for access control in Web application and DB system is also progressed actively. There are many verification method for PKC(Public Key Certificates), which are CRL, OCSP, SCVP and others. But their certificates verification methods for PKC cannot to be applied to PMI(Privilege Management Infrastructure) which is using AC(Attribute certificates) because of synchronization of PKC and AC. It is because AC has no public key, AC Verifier must get the PKC and verify the validity on PKC and AC. So in this paper we proposed the new AC-based certificate verification model. which provide the synchronization in two certificates(AC and PKC).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.419-421
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• 2010

Mobile client-Server synchronization system supporting for field updating of spatio-temporal data could be interrupted incompletely as it has some failure of client-server system and network during synchronizing work. Thus the interruption of synchronizing could make some problem with not progressing normal synchronizing work while re-performing for the consistent error of client-server system and synchronization. This study analyzes defects that are generated at the mobile client-server environment and proposes recovery techniques which can rerun consistence of DB and synchronization.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.273-275
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• 2016

본 논문에서는 서버와 메시지를 주고받을 시 네트워크 환경상의 문제로 발생할 수 있는 메시지 전송 실패 이슈에 대한 신뢰성을 향상시킬 수 있는 3단계 메시지 실패 해결 솔루션을 제안한다. 서버에 업데이트 이슈가 발생시 push 서버를 통해 클라이언트에게 해당 이슈를 전송하게 되는데, 이 때 네트워크 환경상의 문제 등으로 실패 케이스가 발생하는 경우가 있다. 이러한 메시지 전송 실패 이슈에 대한 솔루션으로 재전송 요청, 해당 기능 수행시 서버 DB와 클라이언트 DB 동기화, 학습된 주기를 이용한 폴링(polling) 방식으로 서버로부터 누락된 메시지를 확인 및 실패 처리를 하여 신뢰성을 향상 시키도록 한다.

• Korean Journal of Computational Design and Engineering
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• v.20 no.1
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• pp.55-64
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• 2015

The earthquake is a natural disaster causing loss of life or property damage and happens more often in Korea recently. Moreover, considering the increase of massive buildings, it is required to predict and visualize the information of the vibration in a building. In this paper, we developed a prototype framework to visualize the displacement information in the AR environments. In order to avoid the irregular halts of the scene and the unnatural distortion of the object, this framework uses the synchronization method at the scene update time and the interpolation of the sensor data for the displacement of vertices. In addition, we studied displacement estimation methods with the acceleration data to extend this framework to the system with accelerators.