• Proceedings of the Korea Information Processing Society Conference
• /
• 2007.05a
• /
• pp.129-132
• /
• 2007

장소와 시간에 관계없이 언제든 네트워크에 접속해 컴퓨팅할 수 있는 유비쿼터스 환경은 이제 디지털 기술의 발전으로 전문가 영역에서 생활현장으로 까지 계속 퍼져나가고 있다. 본 논문에서는 언제 어디서나 멀리 떨어진 곳에서도 내 PC를 제어할 수 있는 홈 네트워크 기반의 시스템으로 사용자가 휴대폰을 이용하여 네트워크로 내 PC를 원격으로 제어하는데 초점을 맞춘다. 이는 사용자가 만든 파일(UCC: User Created Contents)을 모바일을 통해 웹으로 전송해줄 수 있는 효과적인 시스템이다. 그리고 사용자들이 자신의 PC에 원하는 파일을 원격으로 이메일 전송하는 기능 중심으로 서버와 클라이언트 간 통신 구조를 소개, 분석한다. 본 논문에서는 위의 결과를 바탕으로 시스템을 구현하고 실험하였다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.6
• /
• pp.1022-1025
• /
• 2008

Session Initiation Protocol (SIP) has become the call control protocol of choice for Voice over IP (VoIP) networks because of its open and extensible nature. However, the integrity of call signaling between sites is of utmost importance, and SIP is vulnerable to attackers when left unprotected. Currently a herby-hop security model is prevalent, wherein intermediaries forward a request towards the destination user agent sewer (UAS) without a user agent client (UAC) knowing whether or not the intermediary behaved in a trusted manner. This paper presents an integrated security model for SIP-based VoIP network by combining hop-by-hop security and end-to-end security.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2007.11a
• /
• pp.640-643
• /
• 2007

기업 네트워크에 대한 보안 위협이 지속적으로 발생함에 따라 네트워크 관리가 중요시 되고 있다. 기업 네트워크의 보안성을 강화하기 위해서는 네트워크상의 각 노드에 설치된 보안 소프트웨어나 취약성이 있는 소프트웨어의 업데이트가 요구된다. 그러나, 일반적인 서버/클라이언트 형태의 소프트웨어 업데이트 서비스는 서버의 부하가 크고 시간효율적이지 못하다. 따라서 본 논문에서는 네트워크의 논리적인 형태를 노드의 상태정보에 따라 바이노미얼 트리로 구성하고, 이를 기반으로 이동 에이전트가 각 노드를 순회하며 소프트웨어를 업데이트할 수 있는 시스템을 제안한다. 제안 시스템을 이용함으로써 서버에 집중되는 부하를 줄이면서 빠른 시간 내에 네트워크 상의 모든 노드의 소프트웨어를 업데이트 할 수 있게 된다.

• The KIPS Transactions:PartD
• /
• v.10D no.2
• /
• pp.327-336
• /
• 2003

Recently the rapid growth of Internet and the construction of high speed networks make many kinds of multimedia services possible. But most of current multimedia services are designed being by client/server model, which incurs high load of central server. In order to solve this problem, we propose a peer-to-peer network-based discovery mechanism for multimedia services. In the proposed scheme, mobile agents that have autonomy and mobility are used to search the location of resources. Use of mobile agents can solve the loss problem of the search result that occurs when the network is unsettled in pure peer-to-peer network. It also supports interoperability in heterogeneous system environments. In the proposed scheme, each host maintains the location information of resources which are locally requested or recently requested by other hosts. So, the proposed scheme has faster response time than the pre-existing mechanisms in pure peer-to-peer network environments.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.9
• /
• pp.17-28
• /
• 2004

Since the Internet has grown into a large communication infrastructure, the network management system to systematically manage the large number of network components has become an essential part of the Internet. The rapid growth of network size has brought into question the scalability of the existing centralized model, such as SNMP (Simple Network Management Protocol) and CMIP (Common Management Information Protocol). Thus, for efficient network management, researches about mobile agent have also been performed recently. This paper presents analytical models of centralized approach based on SNMP protocol, distributed approach based on mobile agent, and mixed mode to make up for shortcomings of SNMP and mobile agent. We compare the performance of these analytical models based on network management response time. Experiment results show that performance of mobile agent and the mixed mode is less sensitive to the delay in WAN network environment. However, SNMP is more efficient for the simple network environment like LAN.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.2
• /
• pp.449-458
• /
• 1999

In real-time systems, the accurate response time and minimal communication delay is highly desired. However, a conventional SNMP uses network resources inefficiently and introduces too much network traffic for periodic requests in particular. This paper presents an extended SNMP called Real-Time SNMP. It is designed to support real-time applications with time constraints to provide more accurate response time and less network traffic for periodic SNMP request PDU which is sent from a management station to agents. In addition, the module of the Real-Time SNMP agent works between management station and each SNMP agent to periodically generate requests for the associated agent. In this paper we have implemented the proposed Real-Time SNMP agent module and extended SNMP PDU. We also show the experimental results that indicated more punctual response time and reduced communication delay using the proposed Real-Time SNMP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.645-648
• /
• 2007

This paper describes database server management system by mobile device. Our system can control database server immediately in any where by mobile device. We have developed the dataset server CE which interface with mobile device, database management system which rons in mobile device and web services which connect the mobile database with desktop database. External mobile device communicate with web service agent via wireless equipment. Our system includes dataset server CE client engine, web service server agent and mobile device management system. Through the test by an application program, we have confirmed that our system operates very well each others.

• The KIPS Transactions:PartC
• /
• v.12C no.2 s.98
• /
• pp.183-190
• /
• 2005

In this thesis, first, we propose I-frame encryption techniques of video data for video data itself encryption and propose license agent that processing user's certification and decryption in client system automatically when user execute encrypted video data in system server. License agent runs user's certification, encryption and decryption of video data based on PID(Public Key Infrastructure) using shared key-pool when execute of video data. Also, compose duplex buffer control and propose real time decryption method using efficient buffer scheduling to reduce much playing delay times that happen processing decryption when execute of videoa data of high-capacity.

• Journal of KIISE:Software and Applications
• /
• v.31 no.12
• /
• pp.1637-1648
• /
• 2004

When digital libraries are developed by the traditional client/sever system using a single agent on the distributed environment, several problems occur. First, as the search method is one dimensional, the search results have little relationship to each other. Second, the results do not reflect the user's preference. Third, whenever a client connects to the server, users have to receive the certification. Therefore, the retrieval of documents is less efficient causing dissatisfaction with the system. I propose a new platform of mobile multiagents for a personal digital library to overcome these problems. To develop this new platform I combine the existing DECAF multiagents platform with the Voyager mobile ORB and propose a new negotiation algorithm and scheduling algorithm. Although there has been some research for a personal digital library, I believe there have been few studies on their integration and systemization. For searches of related information, the proposed platform could increase the relationship of search results by subdividing the related documents, which are classified by a supervised neural network. For the user's preference, as some modular clients are applied to a neural network, the search results are optimized. By combining a mobile and multiagents platform a new mobile, multiagents platform is developed in order to decrease a network burden. Furthermore, a new negotiation algorithm and a scheduling algorithm are activated for the effectiveness of PDS. The results of the simulation demonstrate that as the number of servers and agents are increased, the search time for PDS decreases while the degree of the user's satisfaction is four times greater than with the C/S model.

• Journal of KIISE:Computing Practices and Letters
• /
• v.11 no.2
• /
• pp.112-123
• /
• 2005

The latest E-commerce sites provide personalized services to maximize user satisfaction for Internet user The collaborative filtering is an algorithm for personalized item real-time recommendation. Various supplementary methods are provided for improving the accuracy of prediction and performance. It is important to consider these two things simultaneously to implement a useful recommendation system. However, established studies on collaborative filtering technique deal only with the matter of accuracy improvement and overlook the matter of performance. This study considers representative attribute-neighborhood, recommendation textile set, and similarity grouping that are expected to improve performance to the recommendation agent system. Ultimately, this paper suggests empirical applications to verify the adequacy and the validity on this system with the development of Fashion Design Recommendation Agent System (FDRAS ).