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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 31, Issue 12C - Dec 2006
Volume 31, Issue 12B - Dec 2006
Volume 31, Issue 12A - Dec 2006
Volume 31, Issue 11C - Nov 2006
Volume 31, Issue 11B - Nov 2006
Volume 31, Issue 11A - Nov 2006
Volume 31, Issue 10C - Oct 2006
Volume 31, Issue 10B - Oct 2006
Volume 31, Issue 10A - Oct 2006
Volume 31, Issue 9C - Sep 2006
Volume 31, Issue 9B - Sep 2006
Volume 31, Issue 9A - Sep 2006
Volume 31, Issue 8C - Aug 2006
Volume 31, Issue 8B - Aug 2006
Volume 31, Issue 8A - Aug 2006
Volume 31, Issue 7C - Jul 2006
Volume 31, Issue 7B - Jul 2006
Volume 31, Issue 7A - Jul 2006
Volume 31, Issue 6C - Jun 2006
Volume 31, Issue 6B - Jun 2006
Volume 31, Issue 6A - Jun 2006
Volume 31, Issue 5C - May 2006
Volume 31, Issue 5B - May 2006
Volume 31, Issue 5A - May 2006
Volume 31, Issue 4C - Apr 2006
Volume 31, Issue 4B - Apr 2006
Volume 31, Issue 4A - Apr 2006
Volume 31, Issue 3C - Mar 2006
Volume 31, Issue 3B - Mar 2006
Volume 31, Issue 3A - Mar 2006
Volume 31, Issue 2C - Feb 2006
Volume 31, Issue 2B - Feb 2006
Volume 31, Issue 2A - Feb 2006
Volume 31, Issue 1C - Jan 2006
Volume 31, Issue 1B - Jan 2006
Volume 31, Issue 1A - Jan 2006
Selecting the target year
A Hypothesis Test Approach to Template Selection for UWB Rake Receivers
Lee Joon-Yong ; Yoo Sungyul ; Yoon Sung-Jun ; Ha Dong-Heon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 109~116
Many application scenarios of ultra-wideband(UWB) radio assume non-line-of-sigit(non-LoS) signal propagations. Through-material propagation of UWB signal introduces a distortion of the waveform as well as attenuation, which will introduce a decrease of the correlation coefficient between the correlator template and the received signal. A hypothesis test approach to selection of the template waveform for UWB rake receivers is posed. Linde-Buzo-Gray(LBG) algorithm is used to select the candidate waveforms which are used to setup the hypothesis test. The performance of the algorithm is tested using a set of indoor non-LoS propagation measurement data.
Soft decision for Gray Coded PAM Signals Using Max-Log-MAP
Hyun, Kwang-Min ; Yoon, Dong-Weon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 117~122
In this paper, we present a simple and general soft bit decision expression for a Gray coded PAM signal over additive white Gaussian noise(AWGN) channel with the log likelihood ratio(LLR). In order to reduce the complexity of the LLR calculation, we make the bitwise LLR expression simple by replacing the mathematical max functions of the conventional Max-Log-MAP expression with simple arithmetic functions associated with some deterministic parameters, such as a received value and distance between symbols on a signal space. Taking the implementation issues, like the area of silicon, the power consumption, the timing latency, and so on, into consideration, we submit that the proposed method is a promising alternative way to conventional methods for reconfigurable systems.
Efficient design of LDPC code Using circulant matrix and eIRA code
Bae Seul-Ki ; Kim Joon-Sung ; Song Hong-Yeop ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 123~129
In this paper, we concentrate on reducing the complexity for efficient encoder. We design structural LDPC code using circulant matrix and permutation matrix and eIRA code. It is possible to design low complex encoder by using shift register and differential encoder and interleaver than general LDPC encoder that use matrix multiplication operation. The code designed by this structure shows similar performance as random code. And the proposed codes can considerably reduce a number of XOR gates.
Stereo Image Blind Watermarking Scheme based-on Discrete Wavelet Transform and adaptive Disparity Estimation
Ko Jung-Hwan ; Kim Sung-Il ; Kim Eun-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 130~138
In this paper, a new stereo image watermarking scheme based-on adaptive disparity estimation algorithm is proposed. That is, a watermark image is embedded into the right image of a stereo image pair by using the DWT and disparity information is extracted from this watermarked right image and the left image. And then, both of this extracted disparity information and the left image are transmitted to the recipient through the communication channel. At the receiver, the watermarked right image is reconstructed from the received left image and disparity information through an adaptive matching algorithm. a watermark image is finally extracted from this reconstructed right image. From some experiments using CCETT's 'Manege' and 'Friends' images as a stereo image and English alphabet '3DRC' as a watermark image, it is found that the PSNRs of the watermarked image from the reconstructed right images through the adaptive matching algorithm & DWT is improved 2.03 dB, 3.03 dB and robusted against various attacks. These experimental results also suggest a possibility of practical implementation of an adaptive matching also-rithm-based stereo imagewatermarking scheme proposed in this paper.
Real-time Overlay Video Multicast System
Kang, Ho-Jong ; Song, Hwang-Jun ; Min, Kyung-Won ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 139~147
This paper presents an overlay video multicast system over the Internet. The proposed system consists of two parts, i.e. overlay multicast tree suitable for the real-time video delivery and H.263+ rate control adaptive to overlay multicast tree. Overlay multicast tree is constructed to minimize the average time delay of members, and H.263+ rate control pursues a tradeoff between spatial and temporal qualities to enhance the human visual perceptual quality. Two systems are integrated and tested over the real Internet. And experimental results are provided to show the performance of the proposed system.
A Motion Vector Recovery Method based on Optical Flow for Temporal Error Concealment in the H.264 Standard
Kim, Dong-Hyung ; Jeong, Je-Chang ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 148~155
For the improvement of coding efficiency, the H.264 standard uses new coding tools which are not used in previous coding standards. Among new coding tools, motion estimation using smaller block sizes leads to higher correlation between the motion vectors of neighboring blocks. This characteristic of H.264 is useful for the motion vector recovery. In this paper, we propose the motion vector recovery method based on optical flow. Since the proposed method estimates the optical flow velocity vector from more accurate initial value and optical flow region is limited to 16
16 block size, we can alleviate the complexity of computation of optical flow velocity. Simulation results show that our proposed method gives higher objective and subjective video quality than previous methods.
A New Height Estimation Scheme Using Geometric Information of Stereo Camera based on Pan/tilt control
Ko Jung-Hwan ; Kim Eun-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 156~165
In this paper, a new intelligent moving target tracking and surveillance system basing on the pan/tilt-embedded stereo camera system is suggested and implemented. In the proposed system, once the face area of a target is detected from the input stereo image by using a YCbCr color model and phase-type correlation scheme and then, using this data as well as the geometric information of the tracking system, the distance and 3D information of the target are effectively extracted in real-time. Basing on these extracted data the pan/tilted-imbedded stereo camera system is adaptively controlled and as a result, the proposed system can track the target adaptively under the various circumstance of the target. From some experiments using 480 frames of the test input stereo image, it is analyzed that a standard variation between the measured and computed the estimated target's height and an error ratio between the measured and computed 3D coordinate values of the target is also kept to be very low value of 1.03 and 1.18
on average, respectively. From these good experimental results a possibility of implementing a new real-time intelligent stereo target tracking and surveillance system using the proposed scheme is finally suggested.
Stereo Object Tracking and Multiview image Reconstruction System Using Disparity Motion Vector
Ko Jung-Hwan ; Kim Eun-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 166~174
In this paper, a new stereo object tracking system using the disparity motion vector is proposed. In the proposed method, the time-sequential disparity motion vector can be estimated from the disparity vectors which are extracted from the sequence of the stereo input image pair and then using these disparity motion vectors, the area where the target object is located and its location coordinate are detected from the input stereo image. Being based on this location data of the target object, the pan/tilt embedded in the stereo camera system can be controlled and as a result, stereo tracking of the target object can be possible. From some experiments with the 2 frames of the stereo image pairs having 256
256 pixels, it is shown that the proposed stereo tracking system can adaptively track the target object with a low error ratio of about 3.05
on average between the detected and actual location coordinates of the target object.
A Study on the Design and Implementation of a DSSS-based MODEM for a Right Termination System(FTS)
Lim Keumsang ; Kim Jaehwan ; Cho Hyangduck ; Kim Wooshik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 175~183
This letter proposes a Direct Sequence Spread Spectrum (DS-SS)-based Flight Termination System(FTS) and show the simulation results and implements the system using FRGAs. The DS-SS FTS has immunity interference signals and the influence of jamming signal. Moreover, a DS-SS FTS can provides effects on an authentication and encryption with spread codes. And the system uses more less power than an analog FM system. We used Reed-Solomon (32, 28) code and triple Data Encryption Standard(3DES) for error correction and data encryption. Also we used counter algorithm for unauthenticated device's attack The spread codes of In-phase channel and Quadrature channel were generated by Gold sequence generators. The system was implemented in Altera APEX20K100E FPGA for the ground system and EPF10K100ARC240-3 for the airborne system.
Partial IC Blind Multiuser Detection for CDMA Systems
Woo Dae-Ho ; Yoo Young-Gyo ; Byun Youn-Shik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 184~190
In this paper, we propose the blind multiuser detector which is robust against the effects of near-far and multiuser interference. The proposed detector is composed of the partial IC(interference canceller) and the blind MOE(minimum output energy) multiuser detector. The partial IC partially eliminates interference components from the received signal then the output of partial IC is fed into the input of multiuser detector. Simulation results show that the proposed detector has the robust property but the performance of conventional MOE multiuser detector is rapidly degraded in case of existing both near far and multiuser. Thus, the proposed partial IC BMUD(blind multiuser detection) technique has better performance than the conventional MOE.
Predistorter Design for a Memory-less Nonlinear High Power Amplifier Using the
th-Order Inverse Method for OFDM Systems
Lim, Sun-Min ; Eun, Chang-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 191~199
In this paper, we propose a method to implement a predistorter of the
-th order inverse filter structure to prevent signal distortion and spectral re-growth due to the high PAPR (peak-to-average ratio) of the OFDM signals and the non-linearity of high-power amplifiers. We model the memory-less non-linearity of the high-power amplifier with a polynomial model and utilize the inverse of the model, the
-th order inverse filter, for the predistorter. Once the non-linearity is modeled with a polynomial, since we can determine the
-th order inverse filter only with the coefficients of the polynomial, large memory is not required. To update the coefficients of the non-linear high-power amplifier model, we can use LMS or RLS algorithms. The convergence speed is high since the number of coefficients is small, and the computation is simple since manipulation of complex numbers is not necessary.
A Study on Efficient Key Management Model for Digital Pay-TV System
Yang Hyung-kyu ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 200~207
Recently, with the development of information and communication technology, digital pay-TV technology is paid attention. So the Protection of the provided contents is becoming more important. However, in order to encourage an active based on digital TV, the contents and information sent and received respectively by the broadcaster and the subscriber must be protected. Therefore, in this paper, I analyze the requirements to protect the digital contents, the security and efficiency of the previous digital pay-TV system model. Then I proposed a key management model for digital pay-TV system.
An Empirical Comparison Study on Attack Detection Mechanisms Using Data Mining
Kim, Mi-Hui ; Oh, Ha-Young ; Chae, Ki-Joon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 2C, 2006, Pages 208~218
In this paper, we introduce the creation methods of attack detection model using data mining technologies that can classify the latest attack types, and can detect the modification of existing attacks as well as the novel attacks. Also, we evaluate comparatively these attack detection models in the view of detection accuracy and detection time. As the important factors for creating detection models, there are data, attribute, and detection algorithm. Thus, we used NetFlow data gathered at the real network, and KDD Cup 1999 data for the experiment in large quantities. And for attribute selection, we used a heuristic method and a theoretical method using decision tree algorithm. We evaluate comparatively detection models using a single supervised/unsupervised data mining approach and a combined supervised data mining approach. As a result, although a combined supervised data mining approach required more modeling time, it had better detection rate. All models using data mining techniques could detect the attacks within 1 second, thus these approaches could prove the real-time detection. Also, our experimental results for anomaly detection showed that our approaches provided the detection possibility for novel attack, and especially SOM model provided the additional information about existing attack that is similar to novel attack.