• Information and Communications Magazine
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• v.31 no.2
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• pp.71-82
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• 2014

본 논문에서는 물리 계층에서 보안을 고려한 시스템을 제공하기 위해 Gaussian Wiretap Channel 상황에서 보안 전송을 가능하게 하는 보안 전처리 기법의 설계 방법에 대해서 살펴본다. 무선 통신 채널의 경우, 통신 채널이 누구에게나 개방되어 있기 때문에 무엇보다도 보안에 취약하다. 하지만 숨기고자 하는 보안 메시지를 채널 부호화 및 변조 과정 이전에 보안을 위한 전처리 기법을 적용함으로써 물리계층에서 데이터를 보다 안전하게 전송하는 것이 가능해진다. 이를 위해 기존의 Random하게 생성된 Scrambling matrix를 이용하여 물리계층 보안을 유지하는 전처리 기법을 바탕으로 Scrambling matrix의 hamming distance를 이용하여 높은 보안성 및 신뢰도를 가지는 Scrambling matrix 설계 방법을 제안한다. 또한 부호율 1을 가지는 soft decision decoding 기반의 새로운 보안 전처리 기법을 제안함으로써 물리계층에서의 보안성 확보 가능성을 확인하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.4
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• pp.199-204
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• 2003

This paper proposes reconfigurable hardware structures for spreading and scrambling of multi-mode CDMA systems. The proposed reconfigurable structures supporting IS-95, cdma2000 and WCDMA, include a pseudo noise code generator, a channelization code generator and a control circuit for signal flow control. The proposed reconfigurable structures provide an efficient hardware usage for multi-mode CDMA systems. The synthesis results show the area reduction about 24.7% compared with the original code generators. The proposed structures can provide efficient reconfigurability and high speed operations for future SDR systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.85-88
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• 2008

본 논문에서는 집적 영상 (integral imaging) 방식과 픽셀 스크램블링 (pixel scrambling) 기술을 이용한 광 영상 암호화 (optical image encryption) 방법을 제안한다. 제안한 방법의 부호화 과정에서는 먼저 입력영상을 여러 개의 작은 사이즈의 블록으로 나누어 픽셀 스크램블링을 한 다음 집적 영상 기술을 이용하여 요소 영상(elemental image)을 생성하고, 이 영상의 안정성을 위하여 2차 픽셀 스크램블링을 수행하여 최종 암호화된 영상을 얻는다. 그리고 복호화 과정에서는 암호화된 영상에 광학적인 집적 영상 복원 기법과 역 픽셀 스크램블링 방법을 사용하여 원 영상을 복원한다. 제안하는 광 암호화 방법에 대해서 크로핑과 같은 데이터 손실 및 노이즈에 대한 컴퓨터 적으로 모의실험을 수행하여 강인성과 유용성을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5A
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• pp.521-526
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• 2004

OFDM is a very attractive technique for achieving high-bit-rate data transmission and high spectrum efficiency. However, one of disadvantages of OFDM signal is the high PAPR characteristic when multi-carriers are added up coherently. In this Paper, we propose-scrambling scheme using correlator for PAPR reduction and reducing the amount of PAPR calculations. The simulation results show that this scheme has less computational complexity and reasonable PAPR reduction capability compared to PTS technique.

• Language and Information
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• v.8 no.1
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• pp.53-76
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• 2004

Negative polarity items(NPIs), which function as quantifiers are licensed in a syntactically strict way by negatives, which function as qualifiers, resulting in universal negating interpretations as pairs. We present a proposal to explain the related phenomena, in which the syntax and the semantics are closely related to each other, with Combinatory Categorial Grammar. For this purpose, we first adopt the usual approach to scrambling, but control its overgeneration with the use of markers, taking into account the complex syntactic phenomena involving NPIs and scrambling in Korean. We also propose to utilize polarity intensity as a novel feature, in order to account for the universal negating interpretations when NPIs are combined with negatives. Our proposal also explains the difference in readings when other quantifiers or qualifiers intervene the NPI and the related negatives.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.277-279
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• 2013

스크램블링(Scrambling)은 네트워크에서 영상을 전송할 때 보안을 위해 데이터를 특정한 키에 의해 암호화 하여 전송함으로써, 수신자만이 원본 영상으로 복원할 수 있도록 하는 기술이다. 스크램블링은 전송에서 TDES, AES 뿐만아닌 SEED, AIRA의 암호화 알고리즘을 사용한다. 이 경우 암복호화에 많은 시간이 소요되어 실시간 전송환경에서는 전송속도 저하에 따른 QoS 문제가 발생한다. 이와 같은 문제를 해결하기 위해 기존 연구에서는 속도가 빠른 해쉬 함수를 이용하여 스크램블링 암호화 하는 기법을 제안하였다. 하지만 원본 이미지의 일부가 노출될 경우 이후 원본프레임이 노출될 수 있는 문제점을 가지고 있다. 본 논문에서는 이러한 문제점을 방지하기 위해 다중 해쉬 키 프레임을 이용한 Multi Hash key Frame based Scrambling Encryption 알고리즘을 제안한다. 성능평가에서는 제안하는 스크램블링 기법에 대한 암복호화 비용과 성능을 측정하였으며, 기존기법과 비교하였을 때 원본 노출로 인한 대입공격 취약성 부분을 기존 해쉬 함수의 보안 안전성만큼 향상시켰다.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.700-702
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• 1999

The protection of data which we want to keep secret from invalid users has become a main topic nowadays. This paper introduces a encryption scheme for protecting speech signals from eavesdropping. The proposed encryption scheme adopts a secure voice cryptographic algorithm based on the scrambling in frequency band. In order to improve the conventional speech signal encryption scheme, we have randomly permuted DCT coefficients of speech signal. Simulation results are included to show the performance of the proposed algorithm for secure transmission of speech signals.

• Bulletin of the Korean Chemical Society
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• v.21 no.1
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• pp.97-100
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• 2000

Acid-catalyzed porphyrin formation from meso-aryltripyrromethanes and $25-bis({\alpha}$, - hydroxyl - $\alpha$ -phenyl) methylfuran is studied. The condensation resulted in selective scrambling of tripyrromethanes when the condensation was carried out with catalytic amounts of $BF_3$ in methylene chloride. But the reaction carried out with p-TsOH or $BEt_3$ catalysts in the presence of $NH_4Cl$ in acetonitrile, single porphyrin product was isolated without scrambling of starting tripyrromethane. The yields of porphyrin in these studies were somewhat lower than those of 2+2 condensations or aldehyde-pyrrole condensations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.1-8
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• 2006

In the asynchrous OFCDM(Orthogonal Frequency and Code Division Multiplexing) system, a three-step cell search algorithm is performed for the initial synchronization in the following three steps: OFCDM symbol timing, i.e., Fast Fourier Transform(FFT) window timing is estimated employing guard interval (GI) correlation in the first step, then the frame timing and CSSC (Cell Specific Scrambling Code) group is detected by taking the correlation of the CPICH(Common Pilot Channel) based on the property yeilded by shifting the CSSC phase in the frequency domain. Finally, the CSSC phase within the group is identified in the third step. This paper proposes a modification code(PCSSCG:Patial Cell Specific Scrambling Code Group) of the conventional CPICH based cell search algorithm in the second step which offers MS(Mobile Station) complexity reductions with the nearly same performance. The proposed method is to be compared and verified through the computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1034-1039
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• 2004

Since the major reason of the detection failure is from the consecutive data transitions, it is desirable to limit the MTR(maximum transition run) within two. Therefore, we propose a new MTR code that limits the MTR constraint to 2 and k-constraint to 8. In addition, DC-free coding is performed to overcome the media noise that exits in low frequency of perpendicular recording system. We use a GS (Guided Scrambling) for DC-free coding, and the performance of the code is compared with that of the rate 819 code used in the conventional recording channel by a computer simulation.