• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.235-237
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• 2005

인터넷 사용의 증가로 않은 사람들이 기존의 편지나 엽서를 사용하던 것을 전자 메일(e-mail)로 대체하고 있다. 전자 메일은 텍스트뿐만 아니라 그림, 음성, 동영상까지 전송이 가능하여 필요한 문서들도 첨부가 가능하여 많은 사람들에게 호응을 얻고 있지만 광고 메일이나 음란 사이트 홍보 메일로 사용되면서 많은 전자 메일 사용자들에게 정신적 피해를 주고 있으며 메일링 서비스를 하고 있는 업체들에게 큰 유해를 끼치고 있다. 본 논문에서는 사용자가 요구하지 않은 광고성 스팸 메일을 OTP(One Time Password)를 이용하여 효과적으로 차단하는 모듈을 제안, 설계한다. 기존의 차단 방식은 메일 서버에 저장된 메일들을 삭제하는 방식으로 메일 서버에 많은 과부하를 주며 메일 서버의 저장 용량을 낭비하여 사용자로 하여금 곡 필요한 메일들을 송, 수신 하지 못할 수도 있었다. 본 논문에서 제안하는 시스템은 스팸 메일로 분류된 메일들을 메일 서버 자체에 저장하지 않는 방식을 사용하여서 기존의 문제점을 해결하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.352-355
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• 2013

In this paper, a high power tuneable resonator for a wireless power transfer system based on magnetic resonance is proposed. A spiral structure is used for a self-resonant coil and tuneable trimmer capacitors are added at the edges of resonant coils such that the frequency can be easily tuned. 3D simulation tools and equivalent circuit modeling method are used for predicting self-resonant frequency and scattering parameters according to the change of capacitor values. From the measurement of the prototype WPT system, the resonant frequency could be controlled from 3.0 MHz to 4.5 MHz and the transmission efficiency way over 50 % when the distance between transmitting coil and receiving coil was 160 mm.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.41-46
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• 2014

In this paper, a transceiver of VLC (Visible Light Communication) using LED white lighting has been implemented. We analyzed differences between conventional wireless communication and VLC with high-speed data transmission in a variety of environments, and confirmed symbols which passed through a channel using QAM. In order to get a high data rate, we found some variables that should be considered essentially though experiments. In addition, we set a bandwidth and found an optimal gain according to the distance between transmitter and receiver. We analyzed proposed system model through Labview and finally showed a system performance. The performance showed a 2Mbps QAM data rate in real visible light indoor channels.

• Journal of the Korea Society of Computer and Information
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• v.7 no.4
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• pp.115-120
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• 2002

This paper presents the implementation of IS-95 CDMA signal processor, baseband and Intermediate Frequency(IF) digital converter using Field Programmable Gate Array(FPGA) and ADC/DAC and frequency up/down converter IS-95 CDMA channel processor is generated the pilot channel signal with short PN code and Walsh-code generator. The digital If is composed of FPGA. digital transmit/receive signal processor and high speed analog-to-digital converter(ADC) and digital-to-analog converter(DAC). The frequency up/down converter consisted of filter, mixer, digital attenuator and PLL is analog conversion between intermediate frequency(IF) and baseband. This implemented system can be deployed in the IS-95 CDMA base station device etc.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.51-58
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• 2008

We propose a new duplex which does not require guard resources in MIMO environments. In the proposed duplex, two virtual channels in spatial domain are generated by preceding and postcoding MIMO channels, not to use guard resources in either the time or frequency domain. The capacity can be improved by properly selecting precoder and postcoder. We show the improved capacity of the proposed duplex outperforms conventional duplexes even without guard resources.

• Journal of Broadcast Engineering
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• v.20 no.3
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• pp.464-467
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• 2015

The CBS functionality is defined for emergency alert service in cellular systems. Previously, a cooperative communication technique was proposed for more reliable CBS functionality. However, the relays for cooperative communications may fail in receiving emergency message, which may cause a critical latency. Therefore, we propose a novel cooperative communication technology in this letter, which incudes additional T-DMB functionality in relays. Analytical and empirical evaluations confirm that the proposed method is very suitable for rapid emergency alert broadcast.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.6
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• pp.288-295
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• 2005

Multi-signcryption scheme is an extension of signcryption scheme for multi-signers performing together the signcryption operation on messages, and it provides useful cryptographic functions such as confidentiality and authenticity for the sound circulation of messages through the Internet. In this paper, we show the weaknesses of the previous multi-signcryption schemes. And then we propose a new multi-signcryption scheme that improves the weaknesses and the efficiency of the previous schemes. Our scheme efficiently provides message flexibility, order flexibility, message verifiability, order verifiability, message confidentiality, message unforgeability, non-repudiation and robustness. Therefore, it is suitable for protecting messages and multi-signers from malicious attacks in the Internet.

• Korean Journal of Digital Imaging in Medicine
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• v.7 no.1
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• pp.23-31
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• 2005

원격진료 홈네트워크 아파트 진료용 키오스크 모바일주치의 등으로 대표되는 U-헬스케어에 있어서 기초가 되는 것은 의료정보를 디지털화해서 전자적 자료의 형태로 저장 보관하고 이를 송 수신할 수 있는 기술이라고 할 수 있다. 우리나라의 경우, U-Korea 전략의 하나로 보건복지부가 주축이 되어 2005년 10월 현재 국가보건의료정보화계획(ISP)을 수립하기 위한 작업을 추진중에 있다. 여기서, 예컨대 임상병리검사소견이나 방사선촬영소견 등의 의료정보가 전자적 장치에 의해 디지털화 할 경우 디지털 의료정보가 되는 것이며, 이 가운데 특히 방사선촬영소견 등 방사선분야의 모든 촬영기록이 PACS시스템을 통해 기재되거나 저장 전송될 경우 이를 디지털 의료영상정보라고 할 수 있다. 그런데 오늘날 정보통신기술의 발달로 말미암아 디지털 의료영상정보를 포함한 디지털의료정보는 대량적으로 수집 저장되고 유통 내지 공동활용이 보편화되어 감에 따라 그 의료정보의 보호에 관한 문제가 중요한 이슈로 대두되고 있다. 결론적으로 말하자면, 이러한 디지털 의료영상정보가 전자의무기록(EMR) 형태로 저장 보관되는 경우 이는 전자의무기록에 관한 법률규정이 적용되어 법률적 보호를 받게 되며, 그 보호의 강도는 종래 오프라인 상의 의료정보 보호보다 한층 강화된 규정을 두고 있다. 이와 같은 흐름에 있어서 최근 정부가 국가보건의료정보화계획 수립과 함께 제정작업을 추진하고 있는 가칭 의료정보화촉진 및 개인정보보호에 관한 법률(안)은 시사점이 크다고 보기 때문에 소개하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6B
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• pp.901-907
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• 2010

This paper proposes a standard method for linking data between the U-City Integrated Urban Management Platform and u-service systems through systemization of event identification and standardization of event priority. By applying the proposed method, the incoming events to the Management Platform are listed and processed according to their priority of urgency. The application of the systemized event ID and standardized event priority enables prompt counter-measures against urban emergencies and disasters, which improves the efficiency of business processes by reducing the time and cost to complete required actions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.906-914
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• 2007

In the upstream link of EPON, numerous ONUs In the reverse link of the EPON network, numerous ONUs receive the privileges to use the optical medium from the scheduler of the LOT, but not through the competition with others. Therefore, it is very important to select a proper DBA algorithm to allocatethe frequency band to each ONU in an effectively and fair manner. In our preceding study, we proposed the RC-DBA algorithm that complements many problems in existing DBA algorithms. In this paper, we designed the MAC scheduler for the OLT, which the proposed algorithmwas applied to and implement it in the FPGA. In addition, in order to verify the operation of the scheduler, we developed the embedded Linux based testbed.