• Korean Journal of Materials Research
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• v.6 no.5
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• pp.462-469
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• 1996

1x2 방향성결합형 광 변조기를 LiNbO3 기판상에 양자교환에 의한 자기정렬 방식으로 제작하였다. 양자교환후 광 도파로의 안정을 위해 열처리를 하였다. 본 연구에서는 광 도파로를 제작한 후 열처리 시간에 의한 도파로의 굴절을 변화의 관계에 대하여 연구하였으며 전계효과가 우수한 자기정렬방식을 선택하였다. 제작된 1x2 방향성결합형 광 변조기는 변조전압 8.0V에서 크로스토오크가 -29.5dB의 매우 우수한 특성을 나타내었다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.131-136
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• 2007

토픽맵은 RDF에 기반을 둔 OWL과 많은 유사점을 갖지만, 양자는 역사적, 기술적, 의도하는 목적에서 차이가 있다. 토픽맵은 ISO 표준이지만, OWL은 W3C의 온톨로지 개발 표준언어로서 양자는 각각의 제약언어, 데이터 모델, 그리고 일련의 구문들을 별개로 갖는다. 그러나 토픽맵과 OWL 양자는 지식을 표현하는 온톨로지 언어라는 공통적 특성을 가지며, 술어로직에 기반을 두고 있고, XML포맷이기 때문에 상호간에 매핑이 가능하다. 논문의 목적은 토픽맵과 OWL의 메타모델로부터 온톨로지 정보자원의 공유, 교환, 통합에 접근시킨다. 따라서 각각의 메타모델에서 주요 요소를 추출하고, 이들의 의미적인 측면과 구조적인 측면의 요소들의 손실이 발생되지 않도록 매핑을 수행한다.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.110-111
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• 2004

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.6
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• pp.123-134
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• 2006

We propose a quantum secret sharing protocol which can authenticate more than half of members using GHZ state swapping. The Trusted Third Party, Trent can authenticate all members using previously shared ID among Trent distributing his message and the members wanting to reconstruct the message. Authenticated members can reconstruct a secret message through GHZ swapping. Moreover, this protocol is efficient to expand the number of members to arbitrary number n, so it is a close quantum secret sharing protocol to classical secret sharing protocol.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.230-237
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• 2004

In this paper the effects of inverter ripple currents to the Proton Exchange Membrane Fuel Cell Stack (PEMFCS) is analyzed by the impedance model. The proposed method employs the frequency analysis technique to derive an equivalent impedance model of the fuel cell stack and the effects of the inverter ripple current are investigated. The calculated results m then verified by means of experiments on commercially available PEMFCSs. The experimental results show that the ripple current can contribute up to 10[%] reduction in the available output power.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.1
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• pp.75-86
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• 2023

Public key cryptography algorithm such as RSA and ECC, which are commonly used in current financial transaction services, can no longer guarantee security when quantum computers are realized. Therefore it is necessary to convert existing legacy algorithms to Post-Quantum Cryptography, but it is expected that will take a considerable amount of time to replace them. Hence, it is necessary to study a hybrid method combining the two algorithms in order to prepare the forthcoming transition period. In this paper we propose a hybrid session key exchange protocol that generates a session key by combining the legacy algorithm ECDH and the Post-Quantum Cryptographic algorithm NTRU. We tried the methods that proposed by the IETF for TLS 1.3 based hybrid key exchange, and as a result, it is expected that the security can be enhanced by applying the protocol proposed in this paper to the existing financial transaction session protection solution.

• Korean Journal of Social Welfare
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• v.67 no.4
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• pp.203-226
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• 2015

It is widely accepted that one of the main challenges of the 21st century welfare state is how to harmonize 'Old Welfare, Old Risks' which mostly consists of income maintenance programs with 'New Welfare, New Risks' which actively advances social services. It is in this regard that this paper attempts to define the relationship between the income maintenance programs and social services. For this purpose, it analyses social expenditure of 18 OECD countries during 1980-2006, and subsequently attests, if there is a trade-off relationship between the two, using correlation and Granger panel analysis. It duly concludes that the trade-off relationship between the two is not valid in that the two are better understood as a complementary relationship, not substitute relationship.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.72-80
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• 1998

A method is proposed for directional vector quantization using the wavelet packets. After partitioning the wavelet packet coefficients into 9 edges according to the corresponding directions, it encodes and transmits locally dominant edges. The directions of the edges are encoded with a variable length coding and conditional switching of codebooks, while the contents of them with the vector quantization followed by the variable length index coding. The proposed algorithm is superior to various conventional image coding algorithms in the sense of PSNR, which is relatively more significant at very low bit rate such as 0.1~0.3 bpp. As the proposed algorithm preserves the edges which is the most important for the human visual system, it also provides the reconstructed images of good subjective quality even at very low bit rate.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.141-141
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• 2003

전기-광 효과를 이용한 광변조기, 스위치 등의 소자 구현을 위해 고품질의 Ti:LiNbO$_3$ 광도파로 제작은 필수적이다. LiNbO$_3$ 광도파로는 양자교환(APE) 및 Ti 확산 법으로 제조할 수 있으며 전자의 경우 ne 는 증가, no는 감소되는 경향이 있어 편광도 파로의 제작에 용의하며 후자의 경우 ne 와 no 모두 증가하는 도파로 특성을 갖는다. 이러한, 도파로 소자의 특성 향상을 위해서는 Li out-diffusion 이 억제된 손실이 적은 도파로 제작이 필수적이다. 본 연구에서는 Ti 내부 확산법을 이용한 LiNbO$_3$ 광도파로를 확산분위기를 조건으로 하여 제작하였으며, 온도에 따른 각 이온의 반응 메커니즘에 관하여 관찰하였다.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.443-450
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• 1995

A directional coupler which on the X-cut $LiNbO_3$ substrate is fabricated by using proton exchange method and self-aligned method. After proton exchange process, the waveguide is formed by annealing process. The relation ship between refractive index change of waveguide and maximum output was studied along with the annealing time. A self-aligned method was used to simplify the fabrication process of the waveguide and to maximize the efficiency of electric field. The on-off state of modulator has been observered with the switching of the directional coupler by the electric field effect and also the switching voltage of the directional coupler has been measured with 8.0 [V].