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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 26, Issue 12C - Dec 2001
Volume 26, Issue 12B - Dec 2001
Volume 26, Issue 12A - Dec 2001
Volume 26, Issue 11C - Nov 2001
Volume 26, Issue 11B - Nov 2001
Volume 26, Issue 11A - Nov 2001
Volume 26, Issue 10B - Oct 2001
Volume 26, Issue 10A - Oct 2001
Volume 26, Issue 9B - Sep 2001
Volume 26, Issue 9A - Sep 2001
Volume 26, Issue 8B - Aug 2001
Volume 26, Issue 8A - Aug 2001
Volume 26, Issue 7B - Jul 2001
Volume 26, Issue 7A - Jul 2001
Volume 26, Issue 6B - Jun 2001
Volume 26, Issue 6A - Jun 2001
Volume 26, Issue 5B - May 2001
Volume 26, Issue 5A - May 2001
Volume 26, Issue 4B - Apr 2001
Volume 26, Issue 3B - Mar 2001
Selecting the target year
Error Performance Analysis of a FEC for the Cable Modem
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1803~1811
In this paper, Forward Error Correction(FEC) that is satisfied with ITU-T Recommendation J.83, Annex B(North American Data Over Cable Service Interface Specifications(DOCSIS) for Multimedia Cable Network System(MCNS)) is analyzed. The FEC consist of Reed-Solomon(RS) layer, interleaving layer, randomization layer, and trellis coded modulation(TCM) layer. The effects of quantization of input symbol and of trace-back depth in the Viterbi decoder are simulated over AWGN channels.
Investigation on the Nonideality of 12-Bit Sigma-Delta Modulator with a Signal Bandwidth of 1 MHz
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1812~1819
In this paper, it investigated the permitted limit of the analog nonideality for the SOSOC Σ-Δ modulator design which is satisfied with 1 [MHz] signal bandwidth and 12-bit resolution in the OSR=25. Firstly, it get the SOSOC Σ-Δ modulator model and gain coefficient which is suitable in low voltage for the Σ-Δ modulator design which is satisfied with the specification in the supply voltage 3.3 [Vl. And it provided the performance prediction of the Σ-Δ modulator and the permitted limit of the nonideality by adding the performance degradation facts of the Σ-Δ modulator such as the finite gain of the amplifier, the SR, the closed-loop pole, the switch ON resistance and the capacitor mismatch to the ideal Σ-Δ modulator model. When designed the Σ-Δ modulator which is satisfied with the specification by the base above, it will be able to predict the performance of the Σ-Δ modulator and the guide for the specification of the circuit which composes the Σ-Δ modulator.
Implementation of an Adaptive Equalizer for the Home Phone Lines
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1820~1826
In this paper, we present a modeling scheme for the already-installed two-wire home phone lines with arbitrary topologies and show that the inter-symbol interference due to the topology can be removed using an adaptive equalizer. The transmission characteristics of the arbitrary-configured two-wire home phone lines can be analyzed through the ABCD matrices. The simulation result shows that the impedance mismatch due to the branch lines renders nulls in the frequency response or delayed pulses in the impulse response. These nulls or delayed pulses cause inter-symbol interference that inhibits correct signal detection. An adaptive equalizer is shown to be effective in eliminating the interference. Also, the simulation result shows that the equalizer converges in 1.5 ms at a data rate of 1 Msps at signal-to-noise ratios greater than 15 dB. In addition, from the result of relation between E
and BER(Bit Error Rate), we can see that E
o/ more than 19 dB is required for the data communication with a BER less than 10
Blind Adaptive Equalization of Partial Response Channels
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1827~1840
In digital data transmission/storage systems, the compensation for channel distortion is conducted normally using a training sequence that is known a priori to both the sender and receiver. The use of the training sequences results in inefficient utilization of channel bandwidth. Sometimes, it is also impossible to send training sequences such as in the burst-mode communication. As such, a great deal of attention has been given to the approach requiring no training sequences, which has been called the blind equalization technique. On the other hand, to utilize the limited bandwidth effectively, the concept of partial response (PR) signaling has widely been adopted in both the high-speed transmission and high-density recording/playback systems such as digital microwave, digital subscriber loops, hard disk drives, digital VCRs and digital versatile recordable disks and so on. This paper is concerned with blind adaptive equalization of partial response channels whose transfer function zeros are located on the unit circle, thereby causing some problems in performance. Specifically we study how the problems of blind channel equalization associated with the PR channels can be improved. In doing so, we first discuss the existing methods and then propose new structures for blind PR channel equalization. Our structures have been extensively tested by computer simulation and found out to be encouraging in performance. The results seem very promising as well in terms of the implementation complexity compared to the previous approach reported in literature.
Performance Analysis on Multipath Fading Channel Equalization in a Generalized Filter Bank Based OFDM System
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1841~1847
A novel decision-feedback equalization technique for a generalized filter bank based orthogonal frequency division multiplexing data transmission system operating in a frequency selective multipath fading channel is presented in this paper. At the cost of relatively increased computational complexity in comparison to the conventional OFDM systems, the proposed system achieves a better performance in trims 7f bit error rates. The simulation results confirm of superiority and robustness of our method, particularly, in the low SNR channel environments.
Burst Signal Detecting Algorithm for HomePNA v2.0 Preamble Pattern
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1848~1857
This paper proposes the ETEO and MTEO burst signal detector based on TEO algorithm. These algorithms must be used after STR and AGC operation, but are not related to phase and frequency offset. ETEO algorithm is extended version of original TEO, and MTEO algorithm is proposed for improving the output characteristics of ETEO. Also, modified ETEO and MTEO algorithm are proposed for detection of PREAMBLE64. Optimal threshold value is determined and miss and false alarm probability and FER performance are evaluated by computer simulation. Finally, this paper proposes MTEO algorithm with M=3 to guarantee the Performance that FER is less than 10
Study on the Requirement, Consideration, and Critical Baseline in SAR Design Process for the IFSAR Technique
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1858~1863
SAR data consist of magnitude and phase, and IFSAR technique using phase data is very useful high technology Producing fee height information. To use IFSAR technique effectively in the operation of SAR, this paper suggests the essential requirement and main consideration during SAR design process. Also the critical baseline, one of the principal elements, is derived, and it proposes applicable method through the simulation and discussion to the E-SAR.
Timing Recovery Algorithm with Slop Compensated for Multi-level PAM Signals
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1864~1871
In this paper, new symbol timing recovery algorithm is proposed, which is suitable for the digital communication system with Multi-level PAM signals. In the newly proposed symbol timing recovery algorithm, the timing error function is derived by compensating the several difference values between sampled symbol and neighboring symbol every symbol period with mid samples and decided symbol values. Conventional symbol timing recovery methods did not work well in Multi-level PAM signals, but the newly proposed method can be applied to Multi-level PAM signals as well as QPSK. For the performance analysis, the derived variance of the timing error function and the timing error characteristics of S-curve show that the proposed method has better performance than Gardner method and the modified Gardner method.
Feature-Based Disparity Estimation for Intermediate View Reconstruction of Multiview Images
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1872~1879
As multiview video applications become more popular, correspondence problem for stereo image matching plays an important role in expanding view points. Thus, we propose an efficient dense disparity estimation algorithm considering features of each image pair of multiview image sets. Main concepts of the proposed algorithm are based on the region-dividing-bidirectional-pixel-matching method. This algorithm makes matching process efficient and keeps the reliability of the estimated disparities. Other improvement have obtained by proposed cost function, matching window expanding technique, disparity regularization, and disparity assignment in ambiguous region. These techniques make disparities more stable by removing false disparities and ambiguous regions. The estimated disparities are used to synthesize intermediate views of multiview images. Computer simulation demonstrates the excellence of the proposed algorithm in both subjective and objective evaluations. In addition, processing time is reduced as well.
Recovering Corrupted Motion Vectors Using Edge Direction
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1880~1888
In wireless communication systems, transmission errors degrade the reconstructed image quality severely. Among various techniques which reduce the degradation, the error concealment technique yields good performance without overheads and the modification of the encoder. In this paper, we have proposed the technique for recovering the corrupted motion vector using the edge direction of blocks which surround the corrupted block, when the video information is compressed by H.263 standard. We uses the property that each object in video sequences shows the same motion. For the estimation of edge directions, the first AC coefficients of blocks are used. Extensive simulation results show that the proposed technique yields good performance with a reduced computational complexity.
Hierachically Regularized Motion Estimation Technique
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1889~1896
This paper proposes the hierachically regularized motion estimation technique for the efficient and accurate motion estimation. To use hierachical technique increases the reliability of motion vectors. And the regularization of neighbor vectors decreases bit rate of motion vectors. Also, using fast motion estimation algorithm with a few candidate vectors, the processing time added by regularization can be decreased. In the result of the experiment, the fast motion estimation with hierachical regularization technique achieves less computations and decreases estimation and distribution of false vectors.
Detection of Mass by Interpreting the Mammogram as a Topographic surface
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1897~1907
Manipulation of the Compressed Video for Multimedia Networking : A Bit rate Shaping of the Compressed Video
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1908~1924
Interoperability and inter-working in the various network and media environment with different technology background is very important to enlarge the opportunity of service access and to increase the competitive power of service. The ITU-T and advanced counties are planning ahead for provision of GII enabling user to access advanced global communication services supporting multimedia communication applications, embracing all modes of information. In this paper, we especially forced the heterogeneity of end user applications for multimedia networking. The heterogeneity has several technical aspects, like different medium access methods, heterogeneous coding algorithms for audio-visual data and so on. Among these elements, we have been itemized bit rate shaping algorithm on the compressed moving video. Previous manipulations of video has been done on the uncompressed signal domain. That is, compressed video should be converted to linear PCM signal. To do such a procedures, we should decode, manipulate and then encode the video to compressed signal once again. The traditional approach for processing the video signa1 has several critical weak points, requiring complexity to implement, degradation of image quality and large processing delay. The bit rate shaping algorithm proposed in this paper process the manipulation of moving video on the completely compressed domain to cope with above deficit. With this algorithms. we could realized efficient video bit rate shaping and the result of software simulation shows that this method has significant advantage than that of pixel oriented algorithms.
The FASCO BMA based on Motion Vector Prediction using Spatio-temporal Correlations
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1925~1938
In this paper, a new block-matching algorithm for standard video encoder is presented. The slice competition method is proposed as a new scheme, as opposed to a coarse-to-fine approach. The order of calculating the SAD(Sum of Absolute Difference) to fad the best matching block is changed from a raster order to a dispersed one. Based on this scheme, the increasing SAD curve during its calculation is more linear than that of other curves. Then, the candidates of low probability can be removed in the early stage of calculation. And new MV prediction technique with an adaptive search range scheme also assists the proposed block-matching algorithm. As a result, an average of 13% improvement in computational power is recorded by only the proposed MV prediction technique. Synthetically, the computational power is reduced by 3977∼77% than that of the conventional BMAs. The average MAD is always low in various sequences. The results are also very close to the MAD of the full search block-matching algorithm.
3D Image Conversion of 2D Still Image based-on Differential Area-Moving Scheme
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1938~1945
In this paper, a new scheme for image conversion of the 2D input images into the stereoscopic 3D images by using differential shifting method is proposed. First, the relative depth information is estimated by disparity and occlusion information from the input stereo images and then, each of image objects are segmented by gray-level using the estimated information. Finally, through the differential shifting of the segmented objects according to the horizontal parallax, a stereoscopic 3D image having optimal stereopsis is reconstructed. From some experimental results, it is found that the horizontal disparity can be improved about 1.6dB in PSNR for the reconstructed stereo image using the proposed scheme through comparing to that of the given input image. In the experiment of using the commercial stereo viewer, the reconstructed stereoscopic 3D images, in which each of the segmented objects are horizontally shifted in the range of 4 ∼5 pixels are also found to have the mast improved stereopsis.
A partially occluded object recognition technique using a probabilistic analysis in the feature space
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1946~1956
In this paper, we propose a novel 2-D partial matching algorithm based on model-based stochastic analysis of feature correspondences in a relation vector space, which is quite robust to shape variations as well as invariant to geometric transformations. We represent an object using the ARG (Attributed Relational Graph) model with features of a set of relation vectors. In addition, we statistically model the partial occlusion or noise as the distortion of the relation vector distribution in the relation vector space. Our partial matching algorithm consists of two-phases. First, a finite number of candidate sets areselected by using logical constraint embedding local and structural consistency Second, the feature loss detection is done iteratively by error detection and voting scheme thorough the error analysis of relation vector space. Experimental results on real images demonstrate that the proposed algorithm is quite robust to noise and localize target objects correctly even inseverely noisy and occluded scenes.
Modeling Quantization Error using Laplacian Probability Density function
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1957~1962
Image and video compression requires quantization error model of DCT coefficients for post processing, restoration or transcoding. Once DCT coefficients are quantized, it is impossible to recover the original distribution. We assume that the original probability density function (pdf) is the Laplacian function. We calculate the variance of the quantized variable, and estimate the variance of the DCT coefficients. We can confirm that the proposed method enhances the accuracy of the quantization error estimation.
The Mapping Method for Parallel Processing of SAR Data
In-Pyo Hong ; Jae-Woo Joo ; Han-Kyu Park ;
The Journal of Korean Institute of Communications and Information Sciences, volume 26, issue 11A, 2001, Pages 1963~1970
It is essential design process to analyze processing method and set out top level HW configuration using main parameters before implementation of the SAR processor. This paper identifies the impact of the I/O and algorithm structure upon the parallel processing to be assessed and suggests the practical mapping method fur parallel processing to the SAR data. Also, simulation is performed to the E-SAR processor to examine the usefulness of the method, and the results are analyzed and discussed.