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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 34, Issue 12C - Dec 2009
Volume 34, Issue 12B - Dec 2009
Volume 34, Issue 12A - Dec 2009
Volume 34, Issue 11C - Nov 2009
Volume 34, Issue 11B - Nov 2009
Volume 34, Issue 11A - Nov 2009
Volume 34, Issue 10C - Oct 2009
Volume 34, Issue 10B - Oct 2009
Volume 34, Issue 10A - Oct 2009
Volume 34, Issue 9C - Sep 2009
Volume 34, Issue 9B - Sep 2009
Volume 34, Issue 9A - Sep 2009
Volume 34, Issue 8C - Aug 2009
Volume 34, Issue 8B - Aug 2009
Volume 34, Issue 8A - Aug 2009
Volume 34, Issue 7C - Jul 2009
Volume 34, Issue 7B - Jul 2009
Volume 34, Issue 7A - Jul 2009
Volume 34, Issue 6C - Jun 2009
Volume 34, Issue 6B - Jun 2009
Volume 34, Issue 6A - Jun 2009
Volume 34, Issue 5C - May 2009
Volume 34, Issue 5B - May 2009
Volume 34, Issue 5A - May 2009
Volume 34, Issue 4C - Apr 2009
Volume 34, Issue 4B - Apr 2009
Volume 34, Issue 4A - Apr 2009
Volume 34, Issue 3C - Mar 2009
Volume 34, Issue 3B - Mar 2009
Volume 34, Issue 3A - Mar 2009
Volume 34, Issue 2C - Feb 2009
Volume 34, Issue 2B - Feb 2009
Volume 34, Issue 2A - Feb 2009
Volume 34, Issue 1C - Jan 2009
Volume 34, Issue 1B - Jan 2009
Volume 34, Issue 1A - Jan 2009
Selecting the target year
Equivalence of Hadamard Matrices Whose Rows Form a Vector Space
Jin, Seok-Yong ; Kim, Jeong-Heon ; Park, Ki-Hyeon ; Song, Hong-Yeop ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 635~639
In this paper, we show that any two Hadamard matrices of the same size are equivalent if they have the property that the rows of each Hadamard matrix are closed under binary vector addition. One of direct consequences of this result is that the equivalence between cyclic Hadamard matrices constructed by maximal length sequences and Walsh-Hadamard matrix of the same size generated by Kronecker product can be established.
CCC-NSG : A Security Enhancement of the Bluetooth
Cipher using a Circular-Clock-Controlled Nonlinear Algorithm
Kim, Hyeong-Rag ; Lee, Hoon-Jae ; Moon, Sang-Jae ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 640~648
Summation generator with high period and high linear complexity can be easily implemented by a simple hardware or software and it is proper to apply in mobile security system for ubiquitous environments. However the generator has been some weaknesses from Dawson's divided-and-conquer attack, Golic's correlation attack and Meier's fast correlation attack. In this paper, we propose an improved version(
security level) of
algorithm, CVC-NSG(Circular-Clock-Controlled - Nonlinear Summation Generator), which partially replaces LFSRs with nonlinear FSRs and controls the irregular clock to reinforce it's own weaknesses. Finally, we analyze our proposed design in terms of security and performance.
Watermark Implementation for Real-Time H.264/AVC Encoding
Hong, You-Pyo ; Won, Chee-Sun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 649~653
Although digital image has many advantages including digital image compression and various image processing techniques, the it has the weakness of easy manipulation which led to the development of many digital watermarking techniques. There are various types of digital watermarking algorithms for spatial and spectral domains. This paper presents a watermarking implementation for H.264/AVC codec which is adapted for many multimedia standards.
A Video Encoding Scheme using Adaptive Spatial Resolution Control for Mobile Video Applications
Lee, Hee-Jung ; Lee, Yong-Hee ; Lee, Jong-Hun ; Shin, Heon-Shik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 654~662
Video streams for mobile video streaming can be encoded to fit the available network bandwidth by controlling three factors: temporal resolution, spatial resolution, and picture quality. The controlling of picture quality by modifying the quantization parameter (QP) is most widely used. In this paper, we demonstrate that reducing the spatial resolution adaptively can be more efficient in terms of picture quality and energy consumption in low bit-rate environment, and present a model to find the optimal spatial resolution for the available bandwidth. Adaptive spatial resolution control scheme is especially effective when the bandwidth between the video server and the mobile device varies considerably with time, and when the mobile device is sensitive to energy consumption. Our scheme can improve the picture quality by approximately O.5dB and reduce energy consumption by more than 50% compared to the conventional video coding in low bit-rate environment.
Image Encryption using Non-linear FSR and 2D CAT
Nam, Tae-Hee ; Cho, Sung-Jin ; Kim, Seok-Tae ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 663~670
In this paper, we propose the image encryption method which gradually uses NFSR(Non-linear Feedback Shift Register) and 20 CAT(Two-Dimensional Cellular Automata Transform). The encryption method is processed in the following order. First, NFSR is used to create a PN(pseudo noise) sequence, which matches the size of the original image. Then, the created sequence goes through a XOR operation with the original image and process the encipherment. Next, the gateway value is set to produce a 20 CAT basis function. The produced basis function is multiplied by encryption image that has been converted to process the 20 CAT encipherment. Lastly, the results of the experiment which are key space analysis, entropy analysis, and sensitivity analysis verify that the proposed method is efficient and very secure.
Diagnostic Medical Image Compression Method using Visually Lossless Threshold on JPEG2000
Bong, Jeong-Sik ; Yang, Gi-Joo ; Jeon, Joon-Hyeon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 671~680
The diagnostic medical images(CT, MRI) in PACS require large storage and long transmission time. A simple and cheap way of overcoming these limitations is to increase the compression ratio. However, this requires a clinical validation for accurate diagnostic applications. The aim of this paper is to improve the compression efficiency of lossless JPEG2000 for diagnostic CT images by performing a visual-Iossless threshold filtering in high frequency subband. A proposed method, based on 5/3 reversible DWT, provides different subband-threshold values according to the compression ratio and gives the high subjective quality to reconstructed diagnostic CT images.
Image Contents Based Intra predictive Coding for H.264/AVC
Sin, Se-ill ; Kim, Jin-Tea ; Oh, Jeong-Su ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 681~686
In H.264/Ave, an intra prediction added to the P-frame coding slightly improves both of image quality and bit rate, but greatly increases an amount of computation. In order to reduce the increase in computation, this paper proposes an image contents based intra prediction coding using characteristics that the best intra block mode depends on the image content of a macro block. The proposed algorithm estimates the image content with image complexity and the best inter block mode, and then selects or excludes a intra block mode on the basis of it. The simulation results show that the proposed algorithm reduces average O.OldB in image quality, and increases average 0.38% in the bit rate, but reduces average 37.02% in computation time compared with the conventional algorithm.
Efficient Motion Vector Correction Method m Motion Compensated Interpolation Technique Using Bilateral Motion Estimation
Park, Ji-Yoon ; Lee, Chang-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 687~696
The motion compensated interpolation method is widely used to increase video frame rates. Especially, the bilateral motion estimation technique provides the improved results, since it doesn't make the overlapping and missing blocks in the interpolated frame. However, the motion vectors, which are obtained by the bilateral motion estimation, sometimes require further correction. In this paper, we propose the efficient motion vector.correction method for the bilateral motion estimation technique. By comparing the motion vectors of neighboring blocks and searching the new motion vector after merging the neighboring blocks, the erroneous motion vectors are efficiently corrected. It is shown that the proposed method provides better results, compared with the conventional methods.
Reading Speed Comparison between Operating Modes of a 13.56 MHz RFID System
Je, Young-Dai ; Yang, Hoon-Gee ; Yang, Sung-Hyun ; Quan, Cheng-Hao ; Choi, Gil-Young ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 697~705
This paper presents the theoretical tag-reading speed in the ASK and the PJM mode of a 13.56MHz RFID system which have been adopted in the international standard ISO 18000-3, along with simulation results to support the mathematical analysis. Through the analysis using the number of tag-dependent Q-algorithm, which was known to give relatively fast reading speed, we not only derive the number of slots to read out given tags, but compare the reading speeds of the ASK with that of the PJM mode. Moreover, we present the numerical comparison of two modes which bring the equivalent results as in the theoretical one.
Burst Mode AGC Loop and Preamble Detector for VDL Mode-2
Gim, Jong-Man ; Eun, Chang-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 706~714
In this paper, we proposed a burst mode AGC loop and preamble detector applicable for VDL(VHF Digital Link) mode-2 using D8PSK modulation scheme and the performance analysis of proposed schemes is described. Generally the AGC scheme can be divided into two types, continuos and burst mode AGC. The continuos mode is performed well only with an analog feedback AGC loop. But the analog feedback AGC loop is not suitable for burst mode since its gain lock time is more than preamble duration, which causes the preamble detector misses preamble. Hence a fast digital AGC loop is required for burst mode. Also the AGC loop has to be designed with full gain during idle time to detect bursts although the signal level is very low. If the time to acquire gain lock is slow, the preamble detector fail to detect burst due to saturation of a lot of preamble samples. The receiver performance might be down even if the burst was detected because the preamble is used to estimate several parameters need to demodulation at receiver. In this paper we analysed relationships between the AGC loop and preamble detector. we present an AGC loop and preamble detector in burst mode.
Dual-Cell Combining Detection Method for Reduction of Residual Frequency Offset Influence on Code Acquisition Systems
Chong, Da-Hae ; Lee, Young-Yoon ; Yoon, Tae-Ung ; Lee, Young-Po ; Lee, Myung-Soo ; Yoon, Seok-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 715~723
In this paper, we propose a new detection method called dual-cell combining (DCC) detection for the acquisition in time of spread spectrum codes in the presence of residual frequency offset (RFO). When the RFO exists, the correlation peak used for detection during the acquisition process is split into two neighboring peaks with smaller amplitudes, resulting in considerable degradation in the overall acquisition performance of conventional methods. In the DCC detection method, the decision variable for detection is formed by combining two consecutive correlator outputs so that the influence of the reduction in the correlation peak due to the RFO can be alleviated. Numerical results show that the DCC detection method can offer better mean-time-to-synchrouization performance than the conventional method based on the cell-by-cell detection.
A New CBOC Correlation Function for Next Generation GNSS Signal Synchronization
Lee, Young-Po ; Yoon, Tae-Ung ; Lee, Myung-Soo ; Lee, Young-Yoon ; Kim, Sang-Hun ; Yoon, Seok-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 7C, 2009, Pages 724~729
Binary offset carrier (BOC) signal synchronization is based on the correlation between the received and locally generated BOC signals. Thus, the multiple side-peaks in BOC autocorrelation are one of the main error sources in synchronizing BOC signals. Recently, new correlation functions with no side-peak were proposed for sine and cosine phased BOC signal synchronization, respectively, by the authors . In this paper, we propose a new correlation function with no side-peak for composite BOC (CBOC) signals by using the similar approach to that in the previous work.