• Journal of Digital Convergence
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• v.14 no.9
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• pp.251-264
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• 2016

The purpose of this study is to compose direction about mUC as a communication channel in the company. Recently, many companies have started to adopt or try to vitalize the use of mUC. This study starts from the viewpoint of communication which is the original purpose of SNS or mUC. The purpose and function of life-world are drawn based on Habermas' theory of communicative action. Firstly, this study will check on a difference in usage over the action and articulation between SNS and mUC. Secondly, this study will examine a difference of effect of life-world between SNS and mUC. Thirdly, to check that there is difference according to the user characteristics. The result is that there are differences about action and articulation but little differences of effect to the life-world between SNS and mUC. Also, there is difference according to the user characteristics. This study could contribute to compose direction when a company adopts or vitalizes mUC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.962-970
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• 2011

This paper describes an advanced unified communication system. The advanced unified communications mean a service that integrates basic communications such as call, SMS, email, and chatting with social networking service considered as a new communication channel, presenting a unified user interface. The advanced unified communication system is composed of advanced UC(Unified Communications) applications, open UC service platform, and UC back-end servers. The advanced UC applications consist of web-based application and smart phone application. The open UC service platform provides a variety of service components that enable the third party applications to access basic communications and social network services within an enterprise. The UC back-end servers provide server functionalities for call, SMS, email, and chatting.

• Annual Conference of KIPS
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• 2012.04a
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• pp.714-717
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• 2012

통신기술의 발전으로 사람과 사람의 의사소통에 있어서 IT 기술을 접목시킨 여러 기술들이 발전하고 있다. SIP 기반의 UC 서비스 또한 기업과 고객의 원활한 커뮤니케이션을 위하여 기술이 꾸준히 발전하고 있다. 그러나 UC 서비스 또한 IP 기반의 서비스이기 때문에 여러 가지 보안위협의 노출이 되어 있다. SIP 기반의 서비스는 QoS(Quality of Servic)가 보장되어야 하지만 품질에 중점을 두어 보안위협에 크게 노출 되어 있는 것이 사실이다. 이에 본 논문에서는 SIP 보안 메커니즘인 HTTP Digest 사용자 인증, TLS 홉간 보안, S/MIME을 이용한 단말간의 보안 메커니즘을 적용하고 Virtual Proxy Server를 이용한 보안 시스템을 설계 하였다.

• Journal of KIISE:Information Networking
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• v.36 no.2
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• pp.80-89
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• 2009

A DHT(Distributed Hash Table) based P2P is a method that compensates disadvantages of the existing unstructured P2P method. If a DHT algorithm is used, it can do fast data search and maintain search efficiency independent of the number of peers. The peers in a DHT method send messages periodically to keep the routing table updated. In a mobile environment, the peers in a DHT method should send messages more frequently to keep the routing table updated and reduce the failure of requests. However this results in increasing the overall network traffic. In this paper, we propose a method to reduce the update load of a routing table in the existing DHT by updating it in a reactive way. In the proposed reactive method, a routing table is updated only if a data request is coming whereas it is updated periodically in the existing proactive method. We perform experiments using Chord simulator(I3) made by UC Berkely. The experimental results show the performance improvement of the proposed method compared to the existing method.

• The KIPS Transactions:PartA
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• v.15A no.1
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• pp.35-44
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• 2008

It is important to manage access control for secure ubiquitous applications. In this paper, we present an access-control system for executing policy file which includes access control rules. We implemented Context-aware Access Control Manager(CACM) based on Java Context-Awareness Framework(JCAF) which provides infrastructure and API for creating context-aware applications. CACM controls accesses to method call based on the access control rules in the policy file. We also implemented a support tool to help programmers modify incorrect access control rules using static analysis information, and a simulator for simulating ubiquitous applications. We describe simulation results for several ubiquitous applications.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.761-772
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• 2009

A DHT(Distributed Hash Table) based P2P is a method to overcome disadvantages of the existing unstructured P2P method. If a DHT algorithm is used, it can do a fast data search and maintain search efficiency independent of the number of peer. The peers in the DHT method send messages periodically to keep the routing table updated. In a mobile environment, the peers in the DHT method should send messages more frequently to keep the routing table updated and reduce the failure of a request. Therefore, this results in increase of network traffic. In our previous research, we proposed a method to reduce the update load of the routing table in the existing Chord by updating it in a reactive way, but the reactive method had a disadvantage to generate more traffic than the existing Chord if the number of requests per second becomes large. In this paper, we propose an adaptive method of routing table update to reduce the network traffic. In the proposed method, we apply different routing table update method according to the number of request message per second. If the number of request message per second is smaller than some threshold, we apply the reactive method. Otherwsie, we apply the existing Chord method. We perform experiments using Chord simulator (I3) made by UC Berkeley. The experimental results show the performance improvement of the proposed method compared to the existing methods.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.73-82
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• 2009

The peers in the Chord method send messages periodically to keep the routing table updated. In a mobile P2P network, the peers in the Chord method should send messages more frequently to keep the routing table updated and reduce the failure of a request. However this results in increasing the overall network traffic. In our previous method, we proposed a method to reduce the update load of the routing table in the existing Chord by updating it in a reactive way, but there were disadvantages to generate more traffic if the number of requests per second increases and to have more delay in the request processing time than the existing Chord. In this paper, we propose an improved method of reactive routing table update to reduce the request processing time. In the proposed method, when a data request comes, the routing table is updated only if its information is not recent while it is always updated in the previous method. We perform experiments using Chord simulator (I3) made by UC Berkely. The experimental results show the performance improvement of the proposed method compared to the existing method.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.773-782
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• 2009

A DHT(Distributed Hash Table) based P2P is a method to overcome disadvantages of the existing unstructured P2P method. If a DHT algorithm is used, it can do a fast data search and maintain search efficiency independent of the number of peer. The peers in the DHT method send messages periodically to keep the routing table updated. In a mobile environment, the peers in the DHT method should send messages more frequently to keep the routing table updated and reduce the failure of a request. Therefore, this results in increase of network traffic. In our previous research, we proposed a method to reduce the update load of the routing table in the existing Chord by updating it in a reactive way, but the reactive method had a disadvantage to generate more traffic than the existing Chord if the number of requests per second becomes large. In this paper, we propose an adaptive method of routing table update to reduce the network traffic. In the proposed method, we apply different routing table update method according to the number of request message per second. If the number of request message per second is smaller than some threshold, we apply the reactive method. Otherwsie, we apply the existing Chord method. We perform experiments using Chord simulator (I3) made by UC Berkeley. The experimental results show the performance improvement of the proposed method compared to the existing methods.