Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of Korean Institute of Communications and Information Sciences
Journal Basic Information
Journal DOI :
The Korean Institute of Communications and Information Sciences
Editor in Chief :
Volume & Issues
Volume 28, Issue 12C - Dec 2003
Volume 28, Issue 12B - Dec 2003
Volume 28, Issue 12A - Dec 2003
Volume 28, Issue 11C - Nov 2003
Volume 28, Issue 11B - Nov 2003
Volume 28, Issue 11A - Nov 2003
Volume 28, Issue 10C - Oct 2003
Volume 28, Issue 10B - Oct 2003
Volume 28, Issue 10A - Oct 2003
Volume 28, Issue 9C - Sep 2003
Volume 28, Issue 9B - Sep 2003
Volume 28, Issue 9A - Sep 2003
Volume 28, Issue 8C - Aug 2003
Volume 28, Issue 8B - Aug 2003
Volume 28, Issue 8A - Aug 2003
Volume 28, Issue 7C - Jul 2003
Volume 28, Issue 7B - Jul 2003
Volume 28, Issue 7A - Jul 2003
Volume 28, Issue 6C - Jun 2003
Volume 28, Issue 6B - Jun 2003
Volume 28, Issue 6A - Jun 2003
Volume 28, Issue 5C - May 2003
Volume 28, Issue 5B - May 2003
Volume 28, Issue 5A - May 2003
Volume 28, Issue 4C - Apr 2003
Volume 28, Issue 4B - Apr 2003
Volume 28, Issue 4A - Apr 2003
Volume 28, Issue 3C - Mar 2003
Volume 28, Issue 3B - Mar 2003
Volume 28, Issue 3A - Mar 2003
Volume 28, Issue 2C - Feb 2003
Volume 28, Issue 2B - Feb 2003
Volume 28, Issue 2A - Feb 2003
Volume 28, Issue 1C - Jan 2003
Volume 28, Issue 1B - Jan 2003
Volume 28, Issue 1A - Jan 2003
Volume 28, Issue 9 - 00 2003
Volume 28, Issue 8 - 00 2003
Volume 28, Issue 7 - 00 2003
Volume 28, Issue 6 - 00 2003
Volume 28, Issue 5 - 00 2003
Volume 28, Issue 3 - 00 2003
Volume 28, Issue 2 - 00 2003
Volume 28, Issue 1 - 00 2003
Selecting the target year
Linear Complexities of Sequences over Unknown Symbol Sets and Constructions of Sequences over CF(
) whose Characteristic Polynomials are over GF(
Hong, Yun-Pyo ; Eun, Yu-Chang ; Kim, Jeong-Heon ; Song, Hong-Yeop ;
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 443~451
We propose an appropriate approach of defining the linear complexities (LC) of sequences over unknown symbol set. We are able to characterize those p-ary sequences whose R-tuple versions now eve. GF(
) have the same characteristic polynomial as the original with respect to any basis. This leads to a construction of
-ary sequences whose characteristic polynomial is essentially over GF(p). In addition, we can characterize those
-ary sequences whose characteristic polynomials are uniquely determined when symbols are represented as R-tuples over GF(p) with respect to any basis.
Nonlinear Multilayer Combining Techniques in Bayesian Equalizer Using Radial Basis Function Network
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 452~460
In this paper, an equalizer(RNE) using nonlinear multilayer combining techniques in Bayesian equalizer with a structure of radial basis function network is proposed in order to simplify the structure and enhance the performance of the equalizer(RE) using a radial basis function network. The conventional RE Produces its output using linear combining the outputs of the basis functions in the hidden layer while the proposed RNE produces its output using nonlinear combining the outputs of the basis function in the first hidden layer. The nonlinear combiner is implemented by multilayer perceptrons(MLPs). In addition, as an infinite impulse response structure, the RNE with decision feedback equalizer (RNDFE) is proposed. The proposed equalizer has simpler structure and shows better performance than the conventional RE in terms of bit error probability and mean square error.
DCT Domain Separable Symmetric 2-D Linear Filtering
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 461~467
We propose an efficient method for separable symmetric linear filtering in the DCT domain. First, separable 2-D linear filtering is decomposed into the cascade of 1-D filtering in the DCT domain. We investigate special characteristics of DCT domain filtering matrices when the filter coefficients are symmetric. Then we present the DCT domain 2-D filtering method using these characteristics. The proposed method requires smaller number of multiplications including typical sparseness of DCT coefficients compared to previous DCT domain linear filtering methods. Also, the proposed method is composed of simple and regular operations, which would be appropriate for efficient VLSI implementation.
Design of optimal BPCGH using combination of GA and SA Algorithm
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 468~475
In this Paper, we design an optimal binary phase computer generated hologram for Pattern generation using combined genetic algorithm and simulated annealing algorithm together. To design an optimal binary phase computer generated hologram, in searching process of the proposed method, the simple genetic algorithm is used to get an initial random transmittance function of simulated annealing algorithm. Computer simulation shows that the proposed algorithm has better performance than the genetic algorithm or simulated annealing algorithm of terms of diffraction efficiency
A Preprocessing Approach to Improving the Quality of the Music Produced by the EVRC
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 476~485
This paper proposers a preprocessing approach to improving the quality of the music produced by the EVRC(enhanced variable rate codec) which is one of the CDMA(Code Division Multiple Access) voice codecs. Since the EVRC is optimized only for speech signals, it can deteriorate the quality of the music passed through it. One of the problems with the EVRC-coded music is time-clipping, which usually occurs when subsequent frames are encoded at Rate l/8. Since the EVRC determines the bit rate for an input frame based on the long-term prediction gain, we increase the long-term prediction gain in order for the most of the frames to be encoded at Rate 1 or Rate 1/2. Experimental results show that the approach works well on music signals and the number of time-clipped frames is considerably reduced.
An Enhanced Fuzzy ART Algorithm for The Effective Identifier Recognition From Shipping Container Image
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 486~492
The vigilance threshold of conventional fuzzy ART algorithm decide whether to permit the mismatch between any input pattern and stored pattern. If the vigilance threshold was large, despite of little difference among input and stored patterns, the input pattern may be classified to new category. On the other hand, if the vigilance threshold was small, the similarity between two patterns may be accepted in spite of lots of difference and the input pattern are classified to category of the stored pattern. Therefore, the vigilance threshold for the image recognition must be experientially set for the good result. Moreover, it may occur in the fuzzy ART algorithm that the information of stored patterns is lost in the weight-adjusting process and the rate of pattern recognition is dropped. In this paper, I proposed the enhanced fuzzy ART algorithm that supports the dynamical setting of the vigilance threshold using the generalized intersection operator of fuzzy logic and the weight value being adaptively set in proportional to the current weight change and the previous weight by reflecting the frequency of the selection of winner node. For the performance evaluation of the proposed method, we applied to the recognition of container identifiers from shipping container images. The experiment showed that the proposed method produced fewer clusters than conventional ART2 and fuzzy ART algorithm. and had tile higher recognition rate.
Synchronized One-to-many Media Streaming employing Server-Client Coordinated Adaptive Playout Control
Jo, Jin-Yong ; Kim, Jong-Won ;
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 493~505
A new inter-client synchronization framework for multicast media streaming is proposed employing a server-client coordinated adaptive playout control. The proposed adaptive player controls the playback speed of audio and video by adopting the time-scale modification of audio. Based on the overall synchronization status as well as the buffer occupancy level, the playout speed of each client is manipulated within a perceptually tolerable range. Additionally, the server implicitly helps increasing the time available for retransmission while the clients perform an interactive error recovery mechanism with the assistance of playout control. The network-simulator based simulations show that the proposed framework can reduce the playout discontinuity without degrading the media quality, and thus mitigate the client heterogeneity.
Decision Feedback Detector for Space-Time Block Codes over Time-Varying Channels
Ahn, Kyung-Seung ; Baik, Heung-Ki ;
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 506~513
Most existing space-time coding (STC) schemes have been developed for flat fading channels. To obtain antenna diversity gain, they rely on channel state information (CSI) required at the receiver through channel estimation techniques. This paper proposes a new decision feedback decoding scheme for Alamouti-based space-time block coding (STBC) transmission over time-selective fading channels. In wireless channels, time-selective fading effects arise mainly due to Doppler shift and carrier frequency offset, Modelling the time-selective fading channels as the first-order Gauss-Markov processes, we use recursive algorithms such as Kalman filtering, LMS and RLS algorithms for channel tracking. The proposed scheme consists of the symbol decoding stage and channel tracking algorithms. Computer simulations confirm that the proposed scheme shows the better performance and robustness to time-selectivity.
Shot Change Detection Using Multiple Features and Binary Decision Tree
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 514~522
Contrary to the previous methods, in this paper, we propose an enhanced shot change detection method using multiple features and binary decision tree. The previous methods usually used single feature and fixed threshold between consecutive frames. However, contents such as color, shape, background, and texture change simultaneously at shot change points in a video sequence. Therefore, in this paper, we detect the shot changes effectively using multiple features, which are supplementary each other, rather than using single feature. In order to classify the shot changes, we use binary classification tree. According to this classification result, we extract important features among the multiple features and obtain threshold value for each feature. We also perform the cross-validation and droop-case to verify the performance of our method. From an experimental result, it was revealed that the EI of our method performed average of 2% better than that of the conventional shot change detection methods.
A Study on Applet Control on the Internet Communication using Java Bytecode
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 523~531
Java applets are downloaded from web server through internet and executed in Java Virtual Machine of clients'browser. Before execution of java applets, JVM checks bytecode program with bytecode verifier and performs runtime tests with interpreter. However, these tests will not protect against undesirable runtime behavior of java applets, such as denial of service attack, email forging attack, URL spoofing attack, or annoying sound attack. In order to protect malicious applets, a technique used in this paper is java bytecode modification. This technique is used to restrict applet behavior or insert code appropriate to profiling or other monitoring efforts. Java byte modification is divided into two general forms, class-level modification involving subclassing non-final classes and method-level modification used when control over objects from final classes or interface. This paper showed that malicious applets are controlled by java bytecode modification using proxy server. This implementation does not require any changes in the web sever, JVM or web browser.
Performance of pilot-assisted coded-OFDM-CDMA using low-density parity-check coding in Rayleigh fading channels
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 532~538
In this paper we have investigated a novel approach applying low-density parity-check coding to a COFDM-CDMA system, which operates in a multi-path fading mobile channel. Developed as a linear-block channel coder, the LDPC code is known for a superior signal reception capability in AWGN and/or flat fading channels with respect to increased encoding rates, however, its performance degrades when the communication channel becomes multi-path fading. For a typical multi-path fading mobile channel with a SNR of 16㏈ or lower. in order to obtain a BER lower than 1 out of 10000, the LDPC code with encoding rates below 1:3 requires not only the inherent parity check information but also the piloting information for refreshing front-end equalizer taps of COFDM-CDMA, periodically. For instance, while the 1:3-rate LDPC coded transmission symbol is consisted of data bits and parity-check bits in 1 to 3 proportion, on the other hand, in the proposed method the same rate LDPC transmission symbol contains data bits, parity check bits, and pilot bits in 1 to 2 to 1 proportion, respectively. The included pilot bits are effective not only for channel estimation and channel equalization but for symbol decoding by assisting the parity-check bits, hence, improving SNR vs BER performance over the conventional 1:3-rate LDPC code. The proposed system performance has been verified using computer simulations in multi-path, Rayleigh fading channels, and the results show us that the proposed method out-performs the general LDPC channel coding methods in terms of SNR vs BER measurements.
An improved block matching algorithm for fast motion estimation
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 539~547
According to the PDE scheme, it is desirable to make the value of SAD to be rapidly increased in motion estimation. In this paper, we propose a new block matching algorithm based on the combination of a new scan and search order. In the proposed scan order, a current block is divided by the frequency that is estimated by summing the difference between the mean and the values of the pixels. And then the calculation of SAD is performed from the highest frequency area. In the proposed search order based on DC difference between the current and the candidate block, candidate blocks with low DC are early checked in motion estimation. Simulation results show that the proposed method achieves about 6% computational gain compared with the conventional methods.
An Efficient Transcoding Algorithm For G.723.1 and EVRC Speech Coders
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 548~554
Interoperability is ole the most important factors for a successful integration of the speech network. To accomplish communication between endpoints employing different speech coders, decoder and encoder of each endpoint coder should be placed in tandem. However, tandem coder often produces problems such as poor speech quality, high computational load, and additional transmission delay. In this paper, we propose an efficient transcoding algorithm that can provide interoperability to the networks employing ITU-T G.723.1［1］and TIA IS-127 EVRC［2］speech coders. The proposed transcoding algorithm is composed of four parts: LSP conversion, open-loop pitch conversion, fast adaptive codebook search, and fast fixed codebook search. Subjective and objective quality evaluation confirmed that the speech quality produced by the proposed transcoding algorithm was equivalent to, or better than the tandem coding, while it had shorter processing delay and less computational complexity, which is certified implementing on TMS320C62x.
Simplified RBF Multiuser Receivers of Synchronous DS-CDMA Systems
The Journal of Korean Institute of Communications and Information Sciences, volume 28, issue 5C, 2003, Pages 555~560
For synchronous direct sequence-code division multiple access (DS-CDMA) systems, the authors propose an adaptive radial basis function (RBF) receiver with suboptimal structure that reduces not only the complexity with regard to the number of centers but also the quantity of instructions required per one bit reception. The proposed receiver is constructed with parallel RBF networks. Each RBF network has the same procedure as the conventional RBF receiver. The performance of each RBF network is affected by interferences which are assigned to the other RBF networks because neither RBF network uses the full user set. To combat these interferences, the partial IC technique is employed. Monte Carlo simulations over additive white Gaussian noise (AWGN) channels confirm that the proposed receiver with its reduced complexity is able to obtain near-optimum performance. Moreover, the proposed receiver is able to properly cope with a various environment.