• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.199-208
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• 2009

Recently,IP-based broadcasting systems,such as Mobile-TV and IP-TV, have been widely deployed. These systems require a security system to allow only authorized subscribers access to broadcasting services. We analyzed the Conditional Access System, which is a security system used in the IP-based Pay-TV systems. A weakness of the system is that it does not scale well when the system experiences frequent membership changes. In this paper, we propose a group key distribution protocol which overcomes the scalability problem by reducing communication and computation overheads without loss of security strength. Our experimental results show that computation delay of the proposed protocol is smaller than one of the Conditional Access System. This is attributed to the fact that the proposed protocol replaces expensive encryption and decryption with relatively inexpensive arithmetic operations. In addition, the proposed protocol can help to set up a secure channel between a server and a client with the minimum additional overhead.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.3
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• pp.49-57
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• 2013

Power-saving PC software enables the inexpensive power control, but the installation of the power-saving software in all computers in the organization is not an easy task. Computer users in the organization are usually not cooperative as they do not think the power-saving cost is directly related to themselves. The PC power-saving system provides advantage to driving active participation in which users installs the power saving software by restricting IP address through the power management server. However, the problem with this approach is the security vulnerability to IP spoofing attacks, therefore we need to solve the problem that disrupt the entire network system rather than saving electric power. This paper proposes the security authentication system that can implement the efficiency saving power by providing high security for the members' computer system of the public institutions based on the PC power-saving system. Also, by analyzing it in comparison with other method, it is possible to check that the prospects of safety and efficiency are strengthened.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.109-111
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• 2003

본 논문은 최근 활성화되고 있는 VoIP 서비스 기술에 이동성을 보장하기 위해 Mobile IP기술을 접목시킨 시스템을 설계하고 개발한다. PDA와 같은 임베디드 시스템의 제한된 자원을 효율적으로 이용하기 위한 VoIP 서비스용 시스템에 필요한 요구사항과 문제점들을 분석하고 해결책을 제시한다. 또 이동환경에서의 VoIP 서비스를 제공하기 위해 Mobile IP 통신 모듈을 선계하고 구현한다. 유무선 통합 실험망을 이용하여, 개발된 Mobile IP 기반 VoIP시스템의 기능을 검증하고 향후 방안을 제시한다.

• Journal of information and communication convergence engineering
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• v.1 no.1
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• pp.6-11
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• 2003

In general, standard TCP/IP (transmission control protocol-internet protocol), which is called TCP/IP, is using as the communication basis protocol between any collections of networks that is connected. In this paper, using this TCP/IP implementation of remote control system and suitable program for long distance communication is proposed. This system can make system, which basic Ethernet and TCP/IP used system, to mini modeling, so all module that is using here can be used. Therefore, intention of this paper is to reduce expenses, to effective manage for plant and to increase of productivity as linking each plant of several factory to TCP/IP and Ethernet, and then many control plant and manager minimize the needed course.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.343-346
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• 2002

This paper presents a Prototype system developed for a Bluetooth interfaced VoIP system. The VoIP phone is developed based on tile implementation of a CELP coder on the TI 16bit DSP Processor A PC interfaced with Bluetooth module is used to designing a access point system. Host controller protocol stack is implemented to realize gateway between the wireless and wired line networks. A server application program for user management and call processing, which is based on TCP/IP peer to peer connection, is implemented for tile evaluation of overall interface system.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.749-755
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• 2009

This paper described the design and implementation of the FRA(Fault Recovery Agent) for home network environment based on IP-USN. This system consists of a FDA, FSA, and FRA. FDA is an agent that detects an fault by hooking techniques for multimedia distance education based on IP-USN environment. FSA is an agent that is an fault sharing system for multimedia distance education based on IP-USN environment. FRA is a system that is suitable for recovering software fault for multimedia distance education running on home network environment based on IP-USN. It is necessary for the system to be protected by reactivity of media service instance instead of breaking process of session. This system is limited only for FRA modeling.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.430-433
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• 2003

In this paper, we propose the method of voice packet transformation for the improvement of voice quality in embedded VoIP system terminals. For this purpose, it was analyzed about the RTP header in the voice packet receiving side and designed about the handling method of voice packets by using jitter buffer. Through this analyzed and designed results, by implementing the voice packet transformation method and testing on the self-product VoIP system, we reached that a conclusion is satisfied with performance of VoIP services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.192-202
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• 2004

In this paper we have proposed policy-based network management system architecture for Internet QoS support Mobile IP networks that is divided into four layers(application layer, information management layer, policy control layer, device layer), then we propose an implementation strategy of policy-based network management system to enforce various control and network management operations and a model of policy server using SCOPS(Simple Common Open Policy Service) protocol that is developed in this research. For policy-based mobile IP network management system implementation, we have derived four policy classes(access control, mobile IP operation, QoS control, and network monitoring) and we showed operation procedures for each policy scenarios. Finally we have implemented Internet QoS support policy-based mobile IP network testbed and management system and verified out DiffServ policy enforcement behaviors for a target class service that is arranged a specific bandwidth on network congestion conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2555-2562
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• 2011

Binary CDMA is a new standard technology for wireless communication developed by our country that makes high speed communications and good quality of services. In this paper we researched the development methods and implementation of a wireless VoIP System based on the Binary-CDMA technology that makes it freely installed in any place without phone cables and laying works. We designed the structure of the Binary-CDMA Wireless VoIP System and defined messages and data structures for call control. And then we designed and implemented call control message flow between VoIP terminals for user's communication.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.95-100
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• 2011

The next generation IP-PBX system are demanding multimedia facility to carry out UC(Unified Communication) and voice security also. Therefore, in this paper, we have developed the integrated solution of IP-PBX for the voice security by adopting VPN IPsec based on SIP using tunnel method in transmitting voice data to prevent eavesdrop of voice data and have shared between communication system based on PC and PSTN terminals. In particular, We have developed a video conference, private switching, distributed processing and measured telephone conversation quality. This IP-PBX that is connected Soft-phone provide various optional services.