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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 27, Issue 12C - Dec 2002
Volume 27, Issue 11C - Nov 2002
Volume 27, Issue 10C - Oct 2002
Volume 27, Issue 10A - Oct 2002
Volume 27, Issue 9C - Sep 2002
Volume 27, Issue 8C - Aug 2002
Volume 27, Issue 8B - Aug 2002
Volume 27, Issue 8A - Aug 2002
Volume 27, Issue 7C - Jul 2002
Volume 27, Issue 7B - Jul 2002
Volume 27, Issue 7A - Jul 2002
Volume 27, Issue 6C - Jun 2002
Volume 27, Issue 6B - Jun 2002
Volume 27, Issue 6A - Jun 2002
Volume 27, Issue 5C - May 2002
Volume 27, Issue 4C - Apr 2002
Volume 27, Issue 4B - Apr 2002
Volume 27, Issue 4A - Apr 2002
Volume 27, Issue 3C - Mar 2002
Volume 27, Issue 3B - Mar 2002
Volume 27, Issue 3A - Mar 2002
Volume 27, Issue 2B - Feb 2002
Volume 27, Issue 2A - Feb 2002
Volume 27, Issue 2C - Jan 2002
Volume 27, Issue 1C - Jan 2002
Volume 27, Issue 1B - Jan 2002
Volume 27, Issue 1A - Jan 2002
Volume 27, Issue 9 - 00 2002
Volume 27, Issue 8 - 00 2002
Volume 27, Issue 3 - 00 2002
Volume 27, Issue 12 - 00 2002
Volume 27, Issue 11 - 00 2002
Volume 27, Issue 10 - 00 2002
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The Performance Estiamtion of Turbo Internal Interleaver Using Weight Distribution of Codewords
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 173~179
In this paper, we suggest more precise performance analysis method of turbo interleavers based on two criteria; performance bounds like Union Bound and weight frequency of codewords. In order to present our new method, we employ block pseudo random, and so-called prime interleavers in compliance of 3GPP standard, respectively, We also applied this method to S-random interleavers that have different window size, S. 3GPP complied turbo encoder, decoder, and AWGN channel are implemented by using MATLAB for our performance analysis. According to our analysis, both criteria should be taken into account coincidently to predict the performance of newly designed interleavers.
Soft-Decision Decoding of the [23,12] Golay Code Using Covering Polynomials
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 180~187
The decoding method using covering polynomials is an extended form of error-trapping decoding, and is a simple and effective means to implement decoders for cyclic codes. Covering polynomials can be used for soft-decision decoding as well as for decoding beyond the bounded distance of the code. The implementation complexity is proportional to the number of covering polynomials employed. In this paper, the soft-decision decoding procedure using covering polynomials is described, and the procedure is applied to the [23,12] Golay code. A new set of covering polynomials is derived for the procedure, which is presented as a generalized closed-form solution. The set can be efficiently utilized for decoding a class of cyclic codes including the Golay code. Computer simulation of the described procedure is performed to show the trade-offs between the decoder performance and complexity. It is demonstrated that soft-decision decoding of the Golay code using the derived set of covering polynomials has less than 0.2dB deviation from the optimal performance of maximum-likelihood decoding, with a reduced complexity when compared to the Chase Algorithm 2 combined with hard-decision decoding that has nearly identical performance.
Performance Evaluation of the M-algorithm for Decoding Convolutional Codes
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 188~195
The M-algorithm for decoding convolutional codes can significantly reduce the complexity of the Viterbi algorithm by tracking a fixed number of survivor paths in each level of the decoding trellis. It is an easily-implementable algorithm suited for real-time processing of high-speed data. The algorithm, however, generates a sequence of catastrophic errors when the correct path is not included in the set of survivor paths. In this paper, the performance of the M-algorithm obtained from using various decoding complexity levels, frame lengths, and code constraint lengths is presented. The performance gain is quantified when the algorithm is used in conjunction with codes of increased constraint length. In particular, it is demonstrated the gain from the increased code free distance overcompensates the loss from the correct path being excluded from the survivors, when the frame length is short to moderate. Using 64 survivor paths, the signal-to-noise ratio gain obtained by increasing the constraint length from K=7 to K=9, 11, 15 is respectively 0.6, 0.75, and 08dB, when the frame of length L=100 has the frame error rate of 0.01%.
2.4kbps Speech Coding Algorithm Using the Sinusoidal Model
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 195~204
The Sinusoidal Transform Coding(STC) is a vocoding scheme based on a sinusoidal model of a speech signal. The low bit-rate speech coding based on sinusoidal model is a method that models and synthesizes speech with fundamental frequency and its harmonic elements, spectral envelope and phase in the frequency region. In this paper, we propose the 2.4kbps low-rate speech coding algorithm using the sinusoidal model of a speech signal. In the proposed coder, the pitch frequency is estimated by choosing the frequency that makes least mean squared error between synthetic speech with all spectrum peaks and speech synthesized with chosen frequency and its harmonics. The spectral envelope is estimated using SEEVOC(Spectral Envelope Estimation VOCoder) algorithm and the discrete all-pole model. The phase information is obtained using the time of pitch pulse occurrence, i.e., the onset time, as well as the phase of the vocal tract system. Experimental results show that the synthetic speech preserves both the formant and phase information of the original speech very well. The performance of the coder has been evaluated in terms of the MOS test based on informal listening tests, and it achieved over the MOS score of 3.1.
Estimation of Doppler Spectrum Modes in a Weather Radar for Detection of Hazardous Weather Conditions
Lee, Jong-Gil ;
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 205~210
In a Doppler weather radar, high resolution windspeed profile measurements are needed to provide the reliable detection of hazardous weather conditions. For this purpose, the pulse pair method is generally considered to be the most efficient estimator, However, this estimator has some bias errors due to asymmetric spectra and may yield meaningless results in the case of a multimodal return spectrum. Although the poly-pulse pair method can reduce the bias errors of skewed weather spectra, the modes of spectrum may provide more reliable information than the statistical mean for the case of a multimodal or seriously skewed spectrum. Therefore, the idea of relatively simple mode estimator for a weather radar is developed in this paper, Performance simulations show promising results in the detection of hazardous weather conditions.
An Efficient Compression Algorithm for Simple Computer Cell Animation
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 211~220
In this paper, we propose an efficient algorithm to compress simple computer cell animation at very low bit rate. The structure of proposed algorithm consists of intra frame coding and inter frame coding. In inter frame coding, animation is encoded by color quantization using a palette, rearrangement of index, ADPCM used in JPEG-LS, mapping, classification, and entropy coding. In interframe coding, classifying the characteristics of motion, animation is encoded by block based motion replenishment. Experimental results show that the proposed methods turns out to outperform conventional methods including Flash, FLC, Motion-JPEG, MPEG-1, and MPEG-4.
Moving object segmentation using Markov Random Field
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 221~230
This paper presents a new moving object segmentation algorithm using markov random field. The algorithm is based on signal detection theory. That is to say, motion of moving object is decided by binary decision rule, and false decision is corrected by markov random field model. The procedure toward complete segmentation consists of two steps: motion detection and object segmentation. First, motion detection decides the presence of motion on velocity vector by binary decision rule. And velocity vector is generated by optical flow. Second, object segmentation cancels noise by Bayes rule. Experimental results demonstrate the efficiency of the presented method.
Sub-optimal fractal Coding Scheme Using Iterative Transformation
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 231~239
This paper presents a new fractal coding scheme to find sub-optimal transformation by performing an iterative encoding process. An optimal transformation can be defined as the transformation generating the attractor which is closest to an original image. Unfortunately, it has been well-known that it is actually impossible to find the optimal transformation due to heavy computation. In this paper, however, by means of some new theorems related with the fractal transformation due the attractor, it is shown that for a special case the optimal transformation can be obtained as well as for a general case the sub-optimal transformation. The proposed method based on the theorems obtains the sub-optimal transformation performing an iterative process as if done in decoding. Thus, it requires more computation than the conventional method but improves the image quality. We verify the superiority of the proposed method through the experimental results fur real images, which shows that the proposed method approaches to the optimal method in the performance and is superior to the conventional method.
A new motion-based segmentation algorithm in image sequences
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 240~248
This paper presents a new motion-based segmentation algorithm of moving objects in image sequences. The procedure toward complete segmentation consists of two steps: pixel labeling and motion segmentation. In the first step, we assign a label to each pixel according to magnitude of velocity vector. And velocity vector is generated by optical flow. And, in the second step, we have modeled motion field as a markov random field for noise canceling and make a segmentation of motion through energy minimization. We have demonstrated the efficiency of the presented method through experimental results.
Multi-view residual image coding technique using adaptive quantization and scanning method
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 249~257
Image Retrieval Using the Fusion of Texture Features
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 258~267
We present an image retrieval method for improving retrieval performance by effective fusion of entropy features in wavelet region and wavelet moments. In this method, entropy features are sensitive to the local variation of gray level and well extract valley and edges. These features are effectively applied to contend-based image retrieval by well fusing to wavelet moments that represent texture property in multi-resolution. In order to evaluate the performance of the proposed method. We use Corel Draw Photo DB. Experiment results show that the proposed yields 11% better performance for Corel Draw Photo DB over wavelet moments method.
Region-Based Video Object Extraction Using Potential of frame - Difference Energies
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 268~275
This paper proposes a region-based segmentation algorithm fur extracting a video object by using the cost of potential of frame-difference energies. In the first step of a region-based segmentation using spatial intensity, each frame is segmented into a partition of homogeneous regions finely so that each region does not contain the contour of a video object. The fine partition is used as an initial partition for the second step of spatio-temporal segmentation. In spatio-temporal segmentation, the homogeneity cost for each pair of adjacent regions is computed which reflects the potential between the frame-difference energy on the common contour and the frame-difference energy of the lower potential region of the two. The pair of adjacent regions whose cost is minimal then is searched. The two regions of minimum cost ale merged, which result in updating the partition. The merging is recursively performed until only the contours remain which have Same difference energies of high potential. In the fecal step of post-processing, the video object is extracted removing the contours inside the object.
Color Constancy Algorithm using the Maximum Luminance Surface
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 276~283
This paper proposes a new color constancy algorithm using the maximum luminance surface. This method uses a linear model which represents the characteristics of human visual system. The most important process of linear model is the estimation of the spectral distributions of illumination from an input image. To estimate of the spectral distributions of illumination from an input image, we first estimate spectral distribution functions of reflected light on the brightest surface. Then, we estimate surface reflectance functions corresponding to the maximum luminance surface using a principal component analysis of the given munsell chips. We finally estimate the spectral distributions of illumination in an image. Using an estimated illumination, we recover an image by scaling it regularly for the lightness calibration. From the experimental results, the proposed method was effective in recovering the color images compared with others.
Fast Simulated Annealing Algorithm
The Journal of Korean Institute of Communications and Information Sciences, volume 27, issue 3A, 2002, Pages 284~289
In this paper, we propose the fast simulated annealing algorithm to decrease convergence rate in image segmentation using MRF. Simulated annealing algorithm has a good performance in noisy image or texture image, But there is a problem to have a long convergence rate. To fad a solution to this problem, we have labeled each pixel adaptively according to its intensity before simulated annealing. Then, we show the superiority of proposed method through experimental results.