• 제목, 요약, 키워드: Phase encoding

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저전력 비동기식 시스템 설계를 위한 혼합형 dual-rail data encoding 방식 제안 및 검증 (Mixed Dual-rail Data Encoding Method Proposal and Verification for Low Power Asynchronous System Design)

  • 지화준;김상만;박주성
    • 전자공학회논문지
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    • v.51 no.7
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    • pp.96-102
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    • 2014
  • 본 논문에서는 dual-rail data encoding방식을 적용하여 비동기식시스템을 설계할 때, 신호천이를 줄이고 소비전력을 줄이기 위하여 4-phase handshaking 프로토콜과 2-phase handshaking 프로토콜을 혼합한 dual-rail data encoding방식을 제안한다. 기존의 dual-rail data encoding 4-phase handshaking 프로토콜은 space state가 존재함으로 말미암아 신호 천이가 많이 발생하게 되고 많은 전력소비를 발생한다. 이론적으로 dual-rail data encoding 2-phase handshaking 프로토콜은 dual-rail data encoding 4-phase handshaking 프로토콜보다 빠르고 신호천이도 적지만 표준 라이브러리를 사용하여 설계할 수 없다. 제안하는 혼합형 dual-rail data encoding 방식의 성능을 평가하기 위하여 Adder블록, Multiplier블록, Latch를 포함한 benchmark회로를 설계를 설계하였다. Benchmark회로를 이용하여 시뮬레이션해본 결과, 제안하는 혼합형 dual-rail data encoding방식은 기존의 dual-rail data encoding 4-phase handshaking 프로토콜에 비해 35%이상 전력소비가 감소되는 결과를 얻었다.

웨이블릿 부호화 자기공명영상 (Wavelet Encoded MR Imaging)

  • 김응규;이수종
    • 대한전자공학회:학술대회논문집
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    • pp.343-346
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    • 2005
  • In this study, a basic concept of wavelet encoding and its advantages over Fourier based phase encoding application. Wavelet encoding has been proposed as an alternative way to Fourier based phase encoding in magnetic resonance imaging. In wavelet encoding, the RF pulse is designed to generate wavelet-shaped excitation profile of spins. From the resulting echo signals, the wavelet transform coefficients of spin distribution are acquired and an original spin density is reconstructed from wavelet expansion. Wavelet encoding has several advantages over phase encoding. By minimizing redundancy of the data acquisition in a dynamic series of images, we can avoid some encoding steps without serious loss of quality in reconstructed image. This strategy may be regarded as data compression during imaging. Although there are some limitations in wavelet encoding, it is a promising scheme in a dynamic imaging.

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Accumulation Encoding Technique Based on Double Random Phase Encryption for Transmission of Multiple Images

  • Lee, In-Ho
    • Journal of the Optical Society of Korea
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    • v.18 no.4
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    • pp.401-405
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    • 2014
  • In this paper, we propose an accumulation encoding scheme based on double random phase encryption (DRPE) for multiple-image transmission. The proposed scheme can be used for a low-complexity DRPE system due to the simple structure of the accumulation encoder and decoder. For accumulation encoding of multiple images, all of the previously encrypted data are added, and hence the accumulation encoding can improve the security of the DRPE-encrypted data. We present a scheme for encryption and decryption for DRPE-based accumulation encoding, and a method for accumulation encoding and decoding. Finally, simulation results verify that the DRPE-based accumulation encoding scheme for multiple images is powerful in terms of data security.

Double Random Phase Encryption using Orthogonal Encoding for Multiple-Image Transmission

  • Lee, In-Ho;Cho, Myungjin
    • Journal of the Optical Society of Korea
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    • v.18 no.3
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    • pp.201-206
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    • 2014
  • In this paper we extend double random phase encryption (DRPE) using orthogonal encoding from single-image transmission to multiple-image transmission. The orthogonal encoding for multiple images employs a larger Hadamard matrix than that for a single image, which can improve security. We provide a scheme for DRPE with an orthogonal codec, and a method for orthogonal encoding/decoding for multiple-image transmission. Finally, simulation results verify that the DRPE using orthogonal encoding for multiple images is more secure than both the conventional DRPE and the DRPE using orthogonal encoding for a single image.

Double Random Phase Encryption Based Orthogonal Encoding Technique for Color Images

  • Lee, In-Ho;Cho, Myungjin
    • Journal of the Optical Society of Korea
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    • v.18 no.2
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    • pp.129-133
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    • 2014
  • In this paper, we propose a simple Double random phase encryption (DRPE)-based orthogonal encoding technique for color image encryption. In the proposed orthogonal encoding technique, a color image is decomposed into red, green, and blue components before encryption, and the three components are independently encrypted with DRPE using the same key in order to decrease the complexity of encryption and decryption. Then, the encrypted data are encoded with a Hadamard matrix that has the orthogonal property. The purpose of the proposed orthogonal encoding technique is to improve the security of DRPE using the same key at the cost of a little complexity. The proposed orthogonal encoder consists of simple linear operations, so that it is easy to implement. We also provide the simulation results in order to show the effects of the proposed orthogonal encoding technique.

A Tool for Reconstruction of the Sensitivity Encoded Data with Sensitivity Encoding (SENSE)

  • Yun, Sung-Dae;Song, Myung-Sung;Chung, Jun-Young;Park, Hyun-Wook
    • 대한자기공명의과학회:학술대회논문집
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    • pp.71-71
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    • 2003
  • For fast MRI, the number of phase encoding steps has to be reduced. However, the reconstructed image is aliased if the phase encoding steps don't satisfy Nyquist sampling theory. SENSE is used in order to eliminate the aliasing effect as well as to reduce imaging time. SENSE is a linear algebraic technique applied to the multiple receiver data. In this study, we implement a tool to reconstruct the original image (SENSE image) with Sensitivity Encoding (SENSE)

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랜덤 위상 마스크를 이용한 광 메모리에서의 암호화 특성 (Characteristics of encryption in optical memory using random phase mask)

  • 최진산;양병춘;이병호
    • 대한전기학회:학술대회논문집
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    • pp.1128-1130
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    • 1999
  • Optical encoding method of images using random-phase encoding in both input and Fourier Planes was proposed by Javidi and his group, and the method was realized experimentally by Singh and his group with use of a photorefractive crystal and a phase conjugate wave.[1-2] Recently various techniques have been proposed theorically and experimentally. These include the method using one random-phase mask in the Fourier plane or two random-phase masks in the input and the Fresnel planes.[3] We demonstrate the difference and the problem of the methods using one or two random-phase masks in the Fourier or Fresnel plane. We perform the encoding and decoding in $LiNbO_3$ crystal using degenerate four-wave mixing.

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GPU 컴퓨팅에 의한 고속 Double Random Phase Encoding (Fast Double Random Phase Encoding by Using Graphics Processing Unit)

  • 사이플라흐;문인규
    • 한국멀티미디어학회:학술대회논문집
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    • pp.343-344
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    • 2012
  • With the increase of sensitive data and their secure transmission and storage, the use of encryption techniques has become widespread. The performance of encoding majorly depends on the computational time, so a system with less computational time suits more appropriate as compared to its contrary part. Double Random Phase Encoding (DRPE) is an algorithm with many sub functions which consumes more time when executed serially; the computation time can be significantly reduced by implementing important functions in a parallel fashion on Graphics Processing Unit (GPU). Computing convolution using Fast Fourier transform in DRPE is the most important part of the algorithm and it is shown in the paper that by performing this portion in GPU reduced the execution time of the process by substantial amount and can be compared with MATALB for performance analysis. NVIDIA graphic card GeForce 310 is used with CUDA C as a programming language.

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Effectiveness of a Turbo Direction Change for Reduction of Motion Artifact in Magnetic Resonance Enterography

  • Choi, Kwan-Woo;Son, Soon-Yong;Jeong, Mi-Ae
    • Journal of Magnetics
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    • v.21 no.3
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    • pp.421-424
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    • 2016
  • The purpose of this study is to evaluate an effectiveness of switching turbo direction to improve motion artifacts of small bowels and aorta. From June to October 2015, 60 patients suspected of having Crohn's disease were enrolled. The MR Enterography scans were performed using same protocol other than the turbo direction: with the Z phase encoding (group A) and with Y phase encoding (group B). Qualitative analysis of each group was performed to evaluate the effectiveness of switching turbo direction from Z to Y. As a result, the 5-point Likert scale for paired observers were $2.33{\pm}0.88$ for group A and $3.80{\pm}0.85$ for group B on dynamic contrast enhanced coronal images. In conclusion, group B is proved to be superior to group A and can lessen the motion artifacts derived from phase shifts.

Asynchronous 2-Phase Protocol Based on Ternary Encoding for On-Chip Interconnect

  • Oh, Myeong-Hoon;Kim, Seong-Woon
    • ETRI Journal
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    • v.33 no.5
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    • pp.822-825
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    • 2011
  • Level-encoded dual-rail (LEDR) has been widely used in onchip asynchronous interconnects supporting a 2-phase handshake protocol. However, it inevitably requires 2N wires for N-bit data transfers. Encoder and decoder circuits that perform an asynchronous 2-phase handshake protocol with only N wires for N-bit data transfers are presented for on-chip global interconnects. Their fundamentals are based on a ternary encoding scheme using current-mode multiple valued logics. Using 0.25 ${\mu}m$ CMOS technologies, the maximum reduction ratio of the proposed circuits, compared with LEDR in terms of power-delay product, was measured as 39.5% at a wire length of 10 mm and data rate of 100 MHz.