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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 29, Issue 12C - Dec 2004
Volume 29, Issue 12B - Dec 2004
Volume 29, Issue 12A - Dec 2004
Volume 29, Issue 11C - Nov 2004
Volume 29, Issue 11B - Nov 2004
Volume 29, Issue 11A - Nov 2004
Volume 29, Issue 10C - Oct 2004
Volume 29, Issue 10B - Oct 2004
Volume 29, Issue 10A - Oct 2004
Volume 29, Issue 9C - Sep 2004
Volume 29, Issue 9B - Sep 2004
Volume 29, Issue 9A - Sep 2004
Volume 29, Issue 8C - Aug 2004
Volume 29, Issue 8B - Aug 2004
Volume 29, Issue 8A - Aug 2004
Volume 29, Issue 7C - Jul 2004
Volume 29, Issue 7B - Jul 2004
Volume 29, Issue 7A - Jul 2004
Volume 29, Issue 6C - Jun 2004
Volume 29, Issue 6B - Jun 2004
Volume 29, Issue 6A - Jun 2004
Volume 29, Issue 5C - May 2004
Volume 29, Issue 5B - May 2004
Volume 29, Issue 5A - May 2004
Volume 29, Issue 4C - Apr 2004
Volume 29, Issue 4B - Apr 2004
Volume 29, Issue 4A - Apr 2004
Volume 29, Issue 3C - Mar 2004
Volume 29, Issue 3B - Mar 2004
Volume 29, Issue 3A - Mar 2004
Volume 29, Issue 2C - Feb 2004
Volume 29, Issue 2B - Feb 2004
Volume 29, Issue 2A - Feb 2004
Volume 29, Issue 1C - Jan 2004
Volume 29, Issue 1B - Jan 2004
Volume 29, Issue 1A - Jan 2004
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Definition of Triangle Cell and Effective Generating methodology of Generalized Reed-Holler Coefficients
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 751~762
In this paper, we propose the method to derive new GRM(Generalized Reed-Muller) coefficients for each 2
polarities using Triangle cell. As the existing methods to generate GRM coefficients, there are Green's method to operate transform matrix with a given RM coefficient and Besslich's method to get other polarities using basic transfer matrices repeatedly. In this paper, Triangle cell is defined so as to obtain GRM coefficients efficiently. After arranging 2
given RM coefficients of a first row of Triangle cell, sequence modulo sum is peformed in parallel to low column by a fixed numerical formula. To prove the efficiency of proposed arithmetic method, it is compared with Besslich’s method. As the compared result, to calculate GRM coefficients of all polarities to n input variables, Besslich’s method needs 2
-1) two-input Ex-ORs and the proposed method needs 2
(the number of Ex-ORs for n-1 variables)+3
for the same system complexity - (lo
On p-ary Bent Functions Defined on Finite Fields
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 763~769
It is known that a bent function corresponds to a perfect nonlinear function, which makes it difficult to do the differential cryptanalysis in DES and in many other block ciphers. In this paper, for an odd prime p, quadratic p-ary bent functions defined on finite fields are given from the families of p-ary sequences with optimal correlation properly. And quadratic p-ary bent functions, that is, perfect nonlinear functions from the finite field F
to its prime field
are constructed by using the trace functions. trace functions.
Tonality Detection based on Spectrum Energy in Perceptual Audio Coder
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 770~776
The goal of perceptual audio coder is to reduce redundancy and irrelevancy of audio signal based on the concept of masking. Several studies on masking effect reveal that the masking threshold varies as a function of the noise-like or tone-like nature of audio signals. Therefore, tonality of audio signal influences significantly the quality and efficiency of perceptual audio coder In this paper, we propose a new effective algorithm for tonality measure using spectrum energy. Since the proposed algorithm consists of a few transcendental functions and simple operations, it has lower complexity than MPEG psychoacoustic model-II. The proposed algorithm was tested with some audio signals, and DSP implementation showed that the proposed algorithm could be implemented with 3 MIPS. These results illustrate the efficiency of proposed algorithm in both performance and complexity.
Passband Droop and Stopband Attenuation Improvement of Decimation Filters Using Interpolated Fourth-Order Polynomials
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 777~784
In this paper, a new filter structure to improve frequency response characteristics in decimation filter using CIC(Cascaded Integrator-Comb) filters and half band filters is proposed. Conventional filters improve only passband characteristics, but we propose a new filter which can improve stop band and pass band characteristics simultaneously. Since proposed filter needs only two multiplication, additional implementation cost is not much. And overall linear phase characteristics are maintained since the proposed filter is also linear phase. Finally, filter coefficients quantization effects ate discussed after Verilog-HDL coding.
Fast Modified Zerotree Algorithm
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 785~792
In this paper, we propose a fast and efficient method that improves the performance of embedded zerotree wavelet(EZW) algorithm introduced by Sharipo． In the EZW algorithm, two bits are allocated for a symbol, but it is inefficient for compression and the zerotree coding wastes much time at encoding. In this paper, in order to increase the efficiency of compression, it will be allocated a variable bit for a symbol at each subband. To reduce the encoding time, we use a backscan method and lifting scheme instead of filter bank in wavelet transform. Experimental result are shown that the algorithm suggested in this paper has a better performance about 0.3∼1.5㏈ PSNR while the encoding time was speeded up more than 2-10 times compared with the EZW algorithm.
Development of automatic pipe grading algorithm for a diagnosis of pipe status
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 793~800
In this paper, we propose a new automatic pipe grading algorithm for an efficient management of transmission pipe under the ground. Since the conventional transmission pipe evaluation was conducted by subjective decision made by an individual operator, it was difficult to grade them by means of numerical methods and also hard to realistically construct numerical database system. To solve these problems, we Int obtain some information on the current condition of pipes' sections by shooting laser beam at a regular rate and then apply grading algorithm after complete calculation of minimum diameter of pipe. We use some of preprocessing techniques to reduce noise and also use various color models to consider special conditions of each inner pipe. The measurement of pipes' minimum diameter and decision of grade are performed through a detailed processing stages. By some experimental results performed in the field, we show that over 90 percent of correct grade decisions are made by the proposed algorithm.
Block Adaptive Binarization of Business Card Images Acquired in PDA Using a Modified Quadratic filter
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 801~814
In this paper, we propose a block adaptive binarization (BAB) using a modified quadratic filter (MQF) to binarize business card images acquired by personal digital assistant (PDA) cameras effectively. In the proposed method, a business card image is first partitioned into blocks of 8
8 and the blocks are then classified into character Hocks (CBs) and background blocks (BBs). Each classified CB is windowed with a 24
24 rectangular window centering around the CB and the windowed blocks are improved by the pre-processing filter MQF, in which the scheme of threshold selection in QF is modified. The 8
8 center block of the improved block is barbarized with the threshold selected in the MQF. A binary image is obtained tiling each binarized block in its original position. Experimental results show that the MQF and the BAB have much better effects on the performance of binarization compared to the QF and the global binarization (GB), respectively, for the test business card images acquired in a PDA. Also the proposed BAB using MQF gives binary images of much better quality, in which the characters appear much better clearly, over the conventional GB using QF. In addition, the binary images by the proposed BAB using MQF yields about 87.7% of character recognition rate so that about 32.0% performance improvement over those by the GB using QF yielding about 55.7% of character recognition rate using a commercial character recognition software.
Normalized Region Extraction of Facial Features by Using Hue-Based Attention Operator
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 815~823
A hue-based attention operator and a combinational integral projection function(CIPF) are proposed to extract the normalized regions of face and facial features robustly against illumination variation. The face candidate regions are efficiently detected by using skin color filter, and the eyes are located accurately nil robustly against illumination variation by applying the proposed hue- and symmetry-based attention operator to the face candidate regions. And the faces are confirmed by verifying the eyes with the color-based eye variance filter. The proposed CIPF, which combines the weighted hue and intensity, is applied to detect the accurate vertical locations of the eyebrows and the mouth under illumination variations and the existence of mustache. The global face and its local feature regions are exactly located and normalized based on these accurate geometrical information. Experimental results on the AR face database［8］ show that the proposed eye detection method yields better detection rate by about 39.3% than the conventional gray GST-based method. As a result, the normalized facial features can be extracted robustly and consistently based on the exact eye location under illumination variations.
Design of Adaptive Quantization Tables and Huffman Tables for JPEG Compression of Medical Images
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 824~833
Due to the bandwidth and storage limitations, medical images are needed to be compressed before transmission and storage. DICOM (Digital Imaging and Communications in Medicine) specification, which is the medical images standard, provides a mechanism for supporting the use of JPEG still image compression standard. In this paper, we explain a method for compressing medical images by JPEG standard and propose two methods for JPEG compression. First, because medical images differ from natural images in optical feature, we propose a method to design adaptively the quantization table using spectrum analysis. Second, because medical images have higher pixel depth than natural images do, we propose a method to design Huffman table which considers the probability distribution feature of symbols. Therefore, we propose methods to design a quantization table and Huffman table suitable for medical images. Simulation results show the improved performance compared to the quantization table and the adjusted Huffman table of JPEG standard. Proposed methods which are satisfied JPEG Standard, can be applied to PACS (Picture Archiving and Communications System).
Geometric Correction of Lips Using Lip Information
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 834~841
There can be lips transformed geometrically in the lip images according to the location or the pose of camera and speaker. This transformation of the lip images changes geometric information of original lip phases. Therefore, for enhancing global lip information by using partial information of lips to correct lip phases transformed geometrically, in this paper we propose a method that can geometrically correct lips. The method is composed of two steps - the feature-deciding step and the correcting step. In the former, it is for us to extract key points and features of source image according to the its lip model and to create that of target image according to the its lip model. In the latter, we decide mapping relation after partition a source and target image based on information extracted in the previous step into each 4 regions. and then, after mapping, we unite corrected sub-images to a result image. As experiment image, we use fames that contain pronunciation on short vowels of the Korean language and use lip symmetry for evaluating the proposed algorithm. In experiment result, the correcting rate of the lower lip than the upper lip and that of lips moving largely than little was highly enhanced.
An Optimal Selection of Frame Skip and Spatial Quantization for Low Bit Rate Video Coding
Bu, So-Young ; Lee, Byung-Uk ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 842~847
We present a new video coding technique to tradeoff frame rate and picture quality for low bit rate video coding. We show a model equation for selecting the optimal frame rate from the motion content of the source video. We can determine DCT quantization parameter (QP) using the frame rate and bit rate. For objective video quality measurement we propose a simple and effective error measure for skipped frames. The proposed method enhances the video quality up to 2 ㏈ over the H.263 TMN5 encoder.
A stereo matching algorithm in pixel-based disparity space image
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 848~856
In this paper, a fast stereo matching algorithm based on pixel-wise matching strategy, which can get a stable and accurate disparity map, is proposed. Since a stereo image pair has small differences each other and the differences between left and right images are just caused by horizontal shifts with some order, the matching using a large window will not be needed within a given search range. However, disparity results of conventional pixel-based matching methods are somewhat unstable and wrinkled, the principal direction of disparities is checked by the accumulated cost along a path on array with the dynamic programming method. Experimental results showed that the proposed method could remove almost all disparity noise and set a good quality disparity map in very short time.
Inverse quantization of DCT coefficients using Laplacian pdf
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 857~864
Many image compression standards such as JPEG, MPEG or H.263 are based on the discrete cosine transform (DCT) and quantization method. Quantization error. is the major source of image quality degradation. The current dequantization method assumes the uniform distribution of the DCT coefficients. Therefore the dequantization value is the center of each quantization interval. However DCT coefficients are regarded to follow Laplacian probability density function (pdf). The center value of each interval is not optimal in reducing squared error. We use mean of the quantization interval assuming Laplacian pdf, and show the effect of correction on image quality. Also, we compare existing quantization error to corrected quantization error in closed form. The effect of PSNR improvements due to the compensation to the real image is in the range of 0.2 ∼0.4 ㏈. The maximum correction value is 1.66 ㏈.
Architecture Design for MPEG-2 AAC Filter bank Decoder using Recursive Structure
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 865~873
MPEG-2 Advanced Audio Coding(AAC) is widely used in the multi-channel audio compression standards. And it combines hi인-resolution filter bank prediction techniques, and Huffman coding algorithm to achieve the broadcast-quality audio level at very low data rates. The forward and inverse modified discrete transforms which are operated in the encoder and the decoder of the filter bank need many computations. In this paper, we propose suitable recursive structure at IMDCT processing for MPEG-2 AAC real-time decoder. We confirm the memory, the computation speed and complexity of the proposed structure.
A Common Synthesis Filter for MPEG-2 BC/AAC Audio Using Recursive Structure
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 874~882
MPEG Audio compression algorithm is the international standard for the digital compression of high quality audio using mechanism of the perceptual coding based on psychoacoustic masking. It is necessary to discuss the constraints on designing of common filter banks for MPEG-2 BC and MPEG-2 AAC decoder system, which is not Down yet, mapping audio signals from the time domain into the frequency domain. In this paper, we present an architecture of common synthesis filter whcih can be used for MPEG-2 BC and MPEG-2 AAC decoder using recursive structure. The proposed algorithm is based on recursive architecture that effectively performs common compulsion.
Performance Evaluation of Beamformer for STBC-OFDM Systems
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 883~892
Recently, in order to improve high speed data transmission and spectral efficiency in wireless communication systems, the study on the combination OFDM and space-time coding is active. Also, a solution to improve system capacity in multiuser systems is to use adaptive antennas. In a system using STBC, the signals transmitted from two transmit antennas are superposed at the receive antenna and the interference between two transmit antennas of a user occures. Thus it is difficult to apply the conventional beamforming techniques for single antenna to the systems using space-time coding. In this Paper, we present the MMSE beanforming technique using training sequence for STBC-OFDM systems in reverse link and evaluate the performance by using various parameters in TU and HT channels.
Adaptive Intrusion Tolerance Model and Application for Distributed Security System
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 893~900
While security traditionally has been an important issue in information systems, the problem of the greatest concern today is related to the availability of information and continuity of services. Since people and organizations now rely on distributed systems in accessing and processing critical services and mission, the availability of information and continuity of services are becoming more important. Therefore the importance of implementing systems that continue to function in the presence of security breaches cannot be overemphasized. One of the solutions to provide the availability and continuity of information system applications is introducing an intrusion tolerance system. Security mechanism and adaptation mechanism can ensure intrusion tolerance by protecting the application from accidental or malicious changes to the system and by adapting the application to the changing conditions. In this paper we propose an intrusion tolerance model that improves the developmental structure while assuring security level. We also design and implement an adaptive intrusion tolerance system to verify the efficiency of our model by integrating proper functions extracted from CORBA security modules.
An Algorithm for Scaling Parameter Optimization of Watermarking using Random Dot Images
Lee, In-Jung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 29, issue 6C, 2004, Pages 901~906
For a digital image watermarking some autostereograms are used such as random dot images. In there, the extraction efficiency is good and the distortion rate is low. In this paper, we shall select an optimized scaling parameter which derives low distortion rate and high extraction efficiency, when we use a random dot images as like as autostereograms into some images except for extremely biased gray level images.