• Journal of KIISE:Information Networking
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• v.36 no.5
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• pp.437-455
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• 2009

In the near future, various multicast based services will be provided over clustered wireless networks. To provide multicast services in secure manner, multicast messages are encrypted by using group key which is shared by group members. Therefore, various group key management schemes have been introduced until now. Among them, tree based approach is one of the most representative paradigms in group key management. Traditional tree based approaches effectively reduce rekeying message transmissions of the key distribution center. However, they do not consider the network bandwidth used for transmitting the rekeying messages. In this paper, we firstly present formulas that describe bandwidth consumption of tree based group key management scheme. Based on our formulations, we propose a bandwidth efficient key tree management scheme for clustered wireless networks where membership changes occur frequently. Simulation results show that our scheme effectively reduces the bandwidth consumption used for rekeying compared to existing key tree schemes.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.367-369
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• 2004

근래 정보보안의 필요성이 대두됨에 따라 개인 사용자의 보안 지식이 다방면으로 필요하게 되었다. 특정 그룹에 속한 개인 사용자들의 보안패치나 백신 등에 대한 지식이 비슷한 수준일 수 없으므로 보안패치나 백신 등을 관리해 주는 솔루션이 필요하게 되었다. 이는 통합관제 센터나 흑은 보안패치 자동분배 솔루션를 사용하여 해결할 수 있으나, 시스템 관리자의 지속적인 패치 확인과 업데이트가 필요한 일이다. 시스템 관리자가 벤더를 검색하여 패치를 가져오는 방법은 지극히 주관적이고, 실수로 가져오지 못하거나 혹은 벤더의 업데이트 시간과 맞지 않아 긴급패치를 누락시키는 경우가 종종 발생한다. 또한, 자동분배 솔루션을 사용하는 네트워크의 병합이나 패치분배의 추가에 이렇다 할 대안이 없다. 이 논문에서 제안하는 패치 자동업데이트와 자동구성에 대한 방안은 패치의 누락을 미연에 방지하고 네트워크의 병합 등 패치분배 서버가 늘어나면서 생기는 문제점을 해결해준다.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.191-195
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• 2008

In Ansan (the headquarter of KORDI ; Korea Ocean Research & Development Institute), KOSC(Korea Ocean Satellite Center) is being prepared for acquisition, processing and distribution of sensor data via L-band from GOCI(Geostationary Ocean Color Imager) instrument which is loaded on COMS(Communication, Ocean and Meteorological Satellite); it will be launched in 2009. The basis equipment of KOSC(Electric power, Network, Security) has been constructed in 2007. KOSC is being constructed data processing and management system, GOCI L-band reception system, etc. The final object of KOSC is that maximize the application of GOCI.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.3
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• pp.31-42
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• 2005

We consider a network storage model whose administrator can not be fully trusted. In this model, we assume that all data stored are encrypted for data confidentiality and one owner distributes the decryption key for each time period to users. In this paper, we propose three privilege management schemes. In the first scheme, called Temporal Privilege Management (TPM), we use a symmetric encryption based on one-way function chains for key encapsulation. In the second scheme, called Asymmetric Temporal Privilege Management (ATPM), anyone can encrypt the data using the public key of owner, but only privileged users can decrypt the encrypted data. Finally, we present a scheme to restrict writers' privilege using ID-based signatures in ATPM. In our schemes, the privilege managements are based on the time and the addition of users is efficient. Specially, applying TPM and ATPM, we can solve the back-issue problem.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.01a
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• pp.89-92
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• 2018

본 논문에서는 Edge computing 환경에서 다수의 노드들로 구성된 네트워크의 디바이스를 효율적으로 관리하기 위한 방법을 제안한다. 기존의 클라이언트-서버 모델은 모든 데이터와 그에 대한 요청을 중심 서버에서 처리하기 때문에, 다수의 노드로부터 생성된 많은 양의 데이터를 처리하는 데 빠른 응답속도를 보장하지 못한다. Edge computing은 분담을 통해 네트워크의 부담을 줄일 수 있는 IoT 네트워크에 적합한 방법으로, 데이터를 전송하고 받는 과정에서 네트워크의 대역폭을 사용하는 대신 서로 연결된 노드들이 협력해서 데이터를 처리하고, 또한 네트워크 말단에서의 데이터 처리가 허용되어 데이터 센터의 부담을 줄일 수 있다. 여러병렬 기계학습 모델 중 본 연구에서는 Stale Synchronous Parallel(SSP) 모델을 이용하여 Edge 노드에서 분산기계 학습에 적용하였다.

• Convergence Security Journal
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• v.21 no.2
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• pp.3-10
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• 2021

Nowadays, data-based scientific research is a trend, and the transmission of large amounts of data has a great influence on research productivity. To solve this problem, a separate network structure for transmitting large-scale scientific big data is required. ScienceDMZ is a network structure designed to transmit such scientific big data. In such a network configuration, it is essential to establish an access control list(ACL) for users and resources. In this paper, we describe the R&E Together project and the network structure implemented in the actual ScienceDMZ network structure, and define users and services to which access control policies are applied for safe data transmission and service provision. In addition, it presents a method for the network administrator to apply the access control policy to all network resources and users collectively, and through this, it was possible to achieve automation of the application of the access control policy.

• Convergence Security Journal
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• v.15 no.2
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• pp.63-68
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• 2015

Current ICT(Information & Communication Technology) infrastructures (Internet and server/client communication) are struggling for a wide variety of devices, services, and business and technology evolution. Cloud computing originated simply to request and execute the desired operation from the network of clouds. It means that an IT resource that provides a service using the Internet technology. It is getting the most attention in today's IT trends. In the distributed cloud environments, management costs for the network and computing resources are solved fundamentally through the integrated management system. It can increase the cost savings to solve the traffic explosion problem of core network via a distributed Micro DC. However, traditional flooding methods may cause a lot of traffic due to transfer to all the neighbor DCs. Restricted Path Flooding algorithms have been proposed for this purpose. In large networks, there is still the disadvantage that may occur traffic. In this paper, we developed Lightweight Path Flooding algorithm to improve existing flooding algorithm using hop count restriction.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.203-212
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• 2017

The National Housing Bond Information Relay System is a representative financial information relay system in which institutions are connected with center system. A centralized structure is expensive to construct and operate center, and there is a problem that all networks are disconnected when a failure occurs in the center system. In this paper, we propose the national housing bond information relay system model based on Blockchain technology that can process information safely and efficiently. The proposed model constructs a Blockchain network so that each institution that processes the national housing bond information can transmit information safely, and each institution manages the same distributed ledge by a smart contract. The proposed model can reduce the cost because it can process complicated national housing bond transaction information without a relay center, and a network usage and disk usage decreased by 1.7% and 8.53%.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.5
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• pp.60-70
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• 2011

Vehicle location detection and wireless communication method have be designed along the same lines as GPS, CDMA and WLAN, which is based upon the selecting factors such as state-of-art technology trend, accuracy, stability, and economic feasibility, in order to select the optimum method of information communication networks for integrated "Transportation-Power-Facilities" on the electric bus. In addition, the key features of each alternative for an efficient linkage have been review and the integration methodology for linking among Transportation Charging Center, Transportation(ITS, BIS) Center and smart Grid Center has been drawn up based on a technical level of difficulty of each alternative, political and administrative difficulties, and expense justification.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.817-824
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• 2021

The SDN(Software Defined Networking) technology, which appeared to overcome the limitations of the existing network system, resolves the rigidity of the existing system through the separation of HW and SW in network equipment. These characteristics of SDN provide wide scalability beyond hardware-oriented network equipment, and provide flexible load balancing policies in data centers of various sizes. In the meantime, many studies have been conducted to apply the advantages of SDN to data centers and have shown their effectiveness. The method mainly used in previous studies was to periodically check the server load and perform load balancing based on this. In this method, the more the number of servers and the shorter the server load check cycle, the more traffic increases. In this paper, we propose a new load balancing technique that can eliminate unnecessary traffic and manage server resources more efficiently by reporting to the controller when a specific level of load occurs in the server to solve this limitation.