• Journal of Korea Multimedia Society
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• v.6 no.5
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• pp.831-841
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• 2003

In wireless ATM network, Mobile terminals must offer function and QoS such as terminal of wire ATM network. The fast notification of BS (Base Station) scheduler about ATM cells arriving in mobile terminals is a critical item of the ATM-based centrally controlled MAC protocol. But, Collision is arisen at process that several mobile terminals require data transmission by contention method through uplink and because of re-transmission by collision, throughput of decrease and transmission delay increases. In this paper, We propose the MAC protocol that decide optimized request mini-slot's number considering number of request terminal predicted as statistical and its posterior throughput. According to simulation result, could know that proposed protocol shows high performance delay and throughput.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.189-196
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• 2011

In order to subsitute for the normal mode helical wire antenna, bent monopole antenna combined with a helical structure is proposed as a kind of printed antenna. The antenna which can be operated at 418MHz has been simulated and designed by use of a commercial EM simulator Microwave Studio(MWS). It has been observed that the proposed antenna has good agreements between simulated results and measured results such as the return loss and the radiation pattern. The proposed antenna has been applied practically to the wireless remote controller operationg at 418MHz. It has been observed that the use of the proposed antenna result in similar antenna performance from view point of radiation power when compared with the use of the previous normal mode helical antenna.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.975-982
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• 2006

To cope with the recent developments of info-communication technology and information infrastructure, and in particular, to respond to the environment of wire and wireless communication integration, and also to overcome the limit of the existing web-based Port-MIS, the Ministry of Maritime Affairs and Fisheries is developing a mobile Port-MIS public service system (hereinafter referred to as a mobile Port-MIS). Accordingly, this study analyzes the current situation of the mobile Port-MIS that is under operation of the lust stage, finding out the problems, and suggesting new measures to activate the mobile Port-MIS. We expect this study will be able to suggest a guideline to the government institutions or other related organizations that plan to introduce a mobile technology in the near future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.772-775
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• 2008

As the wireless communication technology developed, the Electric Commerce using a mobile was activated. WPKI was developed in order to guarantee the stability of the Electric Commerce but it is difficult to be ensured for the safe PKI service which is the same at the wire communication in the technical because of restriction of the mobile terminal. In this paper, we propose the authentication system for the electronic financial service which is safe and is effective in consideration of the restrictive characteristic of the mobile terminal. Moreover, the encryption algorithm for the safe electronic signature is proposed. In WPKI, this makes the cross certification of each certificate authority possible. Moreover, a stability was enhanced through the signature authentication using KCDSA and SEED algorithm.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.857-860
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• 2003

경쟁적인 비즈니스 환경에서 기업의 경쟁력 강화와 생산성 증가를 위해 기업 내의 협동작업은 매우 중요하다. 그리고 기업 내의 협동작업은 기업 프로세스에 대한 신속한 대처와 정확한 지원을 위해 시간과 장소에 구애받지 않고 작업할 수 있는 유선 및 무선의 전자적 환경이 제공되어야 한다. 또한 기업 경영 활동의 효율성을 높이기 위해서는 기업 내에 산재해 있는 기존 데이터의 활용을 극대화 하고 기업 내의 기존 시스템들 간의 연계와 확장을 고려하는 방안이 검토되어야 한다. 이에 본 논문에서 우리는 소프트웨어 공학 방법론을 사용하여 재사용성을 증가시키고 유지보수 비용을 절감시킬 뿐만 아니라 EIS(Executive Information System) 및 ERP(Enterprise Resource Planning)와 같은 시스템과의 연계를 보다 쉽게 하는 그룹웨어 시스템을 제안 및 구현하였다. 또한, 우리는 정보의 실시간 공유를 통하여 기업의 이익을 극대화 할 수 있는 협동작업을 지원하기 위한 향상된 도구로써 유 무선 통합시스템과 기업 지식 경영의 가치를 높이기 위한 데이터마이닝 기법이 적용된 의사결정 시스템인 지능형 그룹웨어 어플리케이션을 제안한다.

• The Journal of the Korea Contents Association
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• v.6 no.12
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• pp.12-20
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• 2006

In this paper, we propose electronic payment protocol using GDHP blind signature scheme to activate e-business in the wire/wireless integrated environment. The protocol applied elliptic curve algorithm on the GDHP base and improved the efficiency of the existing blind signature technique on the basis of communication frequency and calculation number. And the protocol accelerated speed and strengthened safety against man-in-the-middle attacks and forward secrecy because the certification between individuals is performed by the session key created by Weil paring using elliptic curve cryptosystem in the limited entity $F_q$ instead of the certification used in the existing PayWord protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5A
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• pp.545-553
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• 2004

Expansion of network environment and multimedia demand universality of application service as HDTV, etc. During these processes, it is essential to process multimedia in real time in the wireless communication system based on mobile phone network and in the wire communication system due to fiber cable and xDSL. So, in this Paper the optimal memory allocation algorithm combines the merit of huffman encoding which is superior in simultaneous decoding ability and lempel-ziv that is distinguished in execution of compress is proposed to improve the channel transmission rate and processing speed in the compressing procedure and is verified in the entropy encoder of HDTV. Because the entropy encoder system using proposed optimal memory allocation algorithm has memory saturation prevention we confirms that the compressing ratio for moving pictures is superior than Huffman encoding and LZW.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.143-155
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• 2006

In this paper, we suggest a network game system that can support video game based on multi-platform for multi-user video game, Latency occurring from the load fluctuation in realtime network game is overcomed by using an initial delay buffering scheme on client, when a real-fire game is played, and shows that stable play for a game is achieved as the result of the scheme. Also, We suggest a retransmission algorithm based on the history of game commands, and this Algorithm supplement shortcomings for packet loss and pocket error on UDP communication.

• Convergence Security Journal
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• v.14 no.5
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• pp.65-74
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• 2014

Phishing scans through wired telephones have been evolving into smissing and pharming. While we use wire or wireless telephones, text messages, e-mails, and online-banking conveniently, the ways of hacking and phishing attacks are getting developed and various. This paper investigates the various aspects of attacks depending on the kinds of phishing and suggests general prevention measures. In addition, the user-oriented practical preventive measures and government-driven long term measures are proposed in this paper. Technological developments, short or long term preventive measures proposed by the government, and continuous public relations could be solutions since in a short time, it could be difficult to eradicate phishing scams evolving continuously. Besides, the internet media as well as SNS are great helps in promoting the preventives against phishing and smissing. Finally this paper asserts that the newly developed service technology should be made carefully without security problems.

• Journal of the Korea Society of Computer and Information
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• v.20 no.12
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• pp.53-59
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• 2015

In this paper, we developed a Hospital Information System in which the business process is formalized and a wire/wireless integrated solution is used. This system consists of the administration office program, the medical office program, the ward management program and the rounds management program. The administration office program can enroll and accept patients, issue and reissue the RFID card. The medical office program inputs a medical examination and treatment, outputs a diagnosis, requests a hospitalization, retrieves the record of a medical examination and treatment, assigns the corresponding examination room to the accepted patients, and updates the number of an waiting patient and a patient number according to the examination room on real time. The ward management program handles hospitalizations and leaving hospital, a nurse's note, and an isolation ward monitoring. The rounds management program handles a medical examination and treatment, and a leaving hospital using PDA. This developed system can be built at low cost and increase the quality of the medical services highly by making it automated the medical administration automation. Also the small number of the medical staffs can manage the inpatients efficiently by using the monitoring functions.