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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 30, Issue 12C - Dec 2005
Volume 30, Issue 12B - Dec 2005
Volume 30, Issue 12A - Dec 2005
Volume 30, Issue 11C - Nov 2005
Volume 30, Issue 11B - Nov 2005
Volume 30, Issue 11A - Nov 2005
Volume 30, Issue 10C - Oct 2005
Volume 30, Issue 10B - Oct 2005
Volume 30, Issue 10A - Oct 2005
Volume 30, Issue 9C - Sep 2005
Volume 30, Issue 9B - Sep 2005
Volume 30, Issue 9A - Sep 2005
Volume 30, Issue 8C - Aug 2005
Volume 30, Issue 8B - Aug 2005
Volume 30, Issue 8A - Aug 2005
Volume 30, Issue 7C - Jul 2005
Volume 30, Issue 7B - Jul 2005
Volume 30, Issue 7A - Jul 2005
Volume 30, Issue 6C - Jun 2005
Volume 30, Issue 6B - Jun 2005
Volume 30, Issue 6A - Jun 2005
Volume 30, Issue 5C - May 2005
Volume 30, Issue 5B - May 2005
Volume 30, Issue 5A - May 2005
Volume 30, Issue 4C - Apr 2005
Volume 30, Issue 4B - Apr 2005
Volume 30, Issue 4A - Apr 2005
Volume 30, Issue 3C - Mar 2005
Volume 30, Issue 3B - Mar 2005
Volume 30, Issue 3A - Mar 2005
Volume 30, Issue 2C - Feb 2005
Volume 30, Issue 2B - Feb 2005
Volume 30, Issue 2A - Feb 2005
Volume 30, Issue 1C - Jan 2005
Volume 30, Issue 1B - Jan 2005
Volume 30, Issue 1A - Jan 2005
Selecting the target year
Performance of UWB Ranging in Multipath and Multiuser Environments
Lee Joon-Yong ; Yoo Sungyul ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1125~1132
Ultra-wideband (UWB) ranging poses a set of time delay estimation problems for designers. The possibility of a large error can be a challenging problem for accurate ranging and positioning. An approximate analysis of large error performance of UWB ranging in multipath and multiuser environments is posed. Both analytical and experimental approaches are taken to evaluate the large error variance in a correlation-based serial search scenario.
Enhanced Two-Step Search Scheme for Rapid and Reliable UWB Signal Acquisition
Kim, Jae-Woon ; Yang, Suck-Chel ; Shin, Yo-An ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1133~1143
In this paper, we propose an enhanced two-step search scheme for rapid and reliable signal acquisition in UWB systems under multipath channels. The proposed TSS-LS (Two-Step Search scheme with the Linear search based Second step) achieves rapid acquisition performance comparable to the conventional TSS-BS (Two-Step Search scheme with the Bit reversal search based Second step) already proposed by the authors, based on the single-dwell search with two-step thresholds and search windows. However, unlike the TSS-BS which employs the bit reversal search in the second step, the proposed TSS-LS utilizes the linear search in the second step to improve the reliability of signal acquisition. Simulation results with multipath channel models by IEEE 802.15.3a show that the two-step search schemes for the UWB signal acquisition can achieve sig nificant reduction of the required mean acquisition time as compared to general search schemes. In addition, we observe that the proposed TSS-LS achieves quite good bit error rate performance for large signal-to-noise ratios, which is favorably comparable to the case of ideal perfect timing.
Efficient Intra Modes for Fast Intra Mode Decision of H.264/AVC
Lee Woong-ho ; Lee Jung-ho ; Cho Ik-Hwan ; Jeong Dong-Seok ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1144~1152
Intra prediction coding is one of the many coding-efficiency oriented tools of H.264/AVC, but it requires high computational complexity. Many fast intra coding algorithms have been proposed to reduce the computational complexity of intra prediction. While most of them have been focused on the mode decision methods themselves, we propose a fast algorithm in which new intra modes are substituted for the conventional intra modes so that the number of intra modes can be reduced. The simulation results show that the proposed method could reduce the encoding time of the overall sequence by
without any noticeable degradation of the coding efficiency.
Adaptive Fast Algorithm for Inter/Intra Prediction in H.264
Jin, Soon-Jong ; Kim, Won-Ki ; Jeong, Je-Chang ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1153~1161
The latest standard H.264 coding methods show better efficiency compared to the former coding standards from the rate distortion point of view, but also lead to high complexity. In this paper, we propose an adaptive and fast inter/intra prediction algorithm for H.264 video coding. In the inter prediction algorithm, an effective and simple mode selection method is proposed, which can adaptively adjust to motion estimation to reduce complexity. And proposed intra prediction algorithm reduces its complexity by using calculated Minimum Rate-Distortion costs in the prediction of Intra
modes. From experiment using JM8.4, our algorithm can reduce about
of computation time as compared to JM, with only negligible PSNR and bitrate degradation.
2D Direct LDA Algorithm for Face Recognition
Cho Dong-uk ; Chang Un-dong ; Kim Young-gil ; Song Young-jun ; Ahn Jae-hyeong ; Kim Bong-hyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1162~1166
A new low dimensional feature representation technique is presented in this paper. Linear discriminant analysis is a popular feature extraction method. However, in the case of high dimensional data, the computational difficulty and the small sample size problem are often encountered. In order to solve these problems, we propose two dimensional direct LDA algorithm, which directly extracts the image scatter matrix from 2D image and uses Direct LDA algorithm for face recognition. The ORL face database is used to evaluate the performance of the proposed method. The experimental results indicate that the performance of the proposed method is superior to DLDA.
Priority Method on Same Co-occurrence Count in Adaptive Rank-based Reindexing Scheme
You Kang Soo ; Yoo Hee Jin ; Jang Euee S. ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1167~1174
In this paper, we propose a priority method on same co-occurrence count in adaptive rank-based reindexing scheme for lossless indexed image compression. The priority on same co-occurrence count in co-occurrence count matrix depends on a front count value on each raw of co-occurrence count matrix, a count value around diagonal line on each raw of the matrix, and a count value around large co-occurrence count on each raw of the matrix. Experimental results show that our proposed method can be reduced up to 1.71 bpp comparing with Zeng's and Pinho's method.
Vision-based hand Gesture Detection and Tracking System
Park Ho-Sik ; Bae Cheol-soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1175~1180
We present a vision-based hand gesture detection and tracking system. Most conventional hand gesture recognition systems utilize a simpler method for hand detection such as background subtractions with assumed static observation conditions and those methods are not robust against camera motions, illumination changes, and so on. Therefore, we propose a statistical method to recognize and detect hand regions in images using geometrical structures. Also, Our hand tracking system employs multiple cameras to reduce occlusion problems and non-synchronous multiple observations enhance system scalability. In this experiment, the proposed method has recognition rate of
that shows more improved
than the conventional appearance method.
Simplified PAR Reduction Technique for MIMO-OFDM System
Song Hyoung-Kyu ; Kook Hyung-Joon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1181~1185
A combining of MIMO signal processing with OFDM is regarded as a promising solution of enhancing the performance of next generation wireless system. Therefore, in this paper, an OFDM-based wireless system employing layered space-time architecture is considered for a high-rate transmission. In the MIMO-OFDM system, we evaluate the PAR performance using the SLM approaches. The investigated SLM scheme for MIMO-OFDM signals selects the transmitted sequence with lowest average PAR over all transmitting antennas and retrieves the side information very accurately at the expense of a slight degradation of the PAR performance. The low probability of false side information can improve the overall detection performance of the MIMO-OFDM system with erroneous side information compared to the ordinary SLM approache, respectively. Also, we provide closed form of the average BER performance in MIMO-OFDM system using analytic approach.
A Novel Channel Estimation Method Using Pilot Channels for Frequency-Interleaved MC-CDMA Systems
Cho Young-bo ; Lee Jae-Gu ; Oh seong-Mok ; Kang Chang-eon ; Hong Dae-sik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1186~1192
In this paper, we propose a novel channel estimation method based on pilot channel in a frequency interleaved multicarrier code division multiple access (MC-CDMA). Using the chip interleaving (CI) technique in the frequency domain make it possible to achieve higher frequency diversity gain than the system with conventional symbol interleaving. However, in CI-MC-CDMA systems, a pilot channel-based channel estimation (PCCE) cannot be applied because the orthogonality between pilot symbols and the data symbol is not maintained. The proposed method alters the system structure in order to maintain orthogonality between data and pilot channels over two consecutive subcarriers. Therefore, it can obtain accurate channel state information (CSI) in CI-MC-CDMA.
Hardware Implementation of Chaotic System for Security of JPEG2000
Seo Young-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1193~1200
In this paper, we proposed an image hiding method which decreases the amount of calculation encrypting partial data rather than the whole image data using a discrete wavelet transform and a linear scalar quantization which have been adopted as the main technique in JPEG2000 standard and then implemented the proposed algorithm to hardware. A chaotic system was used instead of encryption algorithms to reduce further amount of calculation. It uses a method of random changing method using the chaotic system of the data in a selected subband. For ciphering the quantization index it uses a novel image encryption algorithm of cyclical shifting to the right or left direction and encrypts two quantization assignment method (Top-down coding and Reflection coding), made change of data less. The experiments have been performed with the proposed methods implemented in software for about 500 images. The hardware encryption system was synthesized to find the gate-level circuit with the Samsung
Phantom-cell library and timing simulation was performed, which resulted in the stable operation in the frequency above 100MHz.
A Time-Sharing TX/RX Control Technique for the Rejection of Feedback Noise Jamming Interference
Jeong Un-Seob ; Ra Sung-Woong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1201~1207
When the isolation between transmitter and receiver in Electronic Warfare equipment is not sufficient, the radiated noise jamming signal from the transmitter feeds back into the receiver and interferes with receiving radar pulse signal. Therefore pulse jamming and noise jamming can't be performed together in the same frequency bands. In this paper, we present a time-sharing TX/RX control technique of the switch matrix which inhibits the transmission of noise jamming signal by using the predicted gate of pulse train and also makes the corresponding channel filter operate to receive the radar pulse signal during the predicted gate pulse. This technique was implemented by EPLD and confirmed by experiment. The proposed technique enables the pulse jamming and the noise jamming to be simultaneously executed in multiple jamming environments.
Adaptive Multiple Antenna Transmission Scheme in DS-UWB System
Song Hyoung-Kyu ; Kook Hyung-Joon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1208~1213
Recently, ultra wideband(UWB) is emerging as a solution for the IEEE 802.15.3a(TG3a) standard because of its potential to enable high-speed data transmission with low power consumption. One of the submitted systems as s PHY proposal is M-ary biorthogonal keying direct sequence ultra wideband(M-BOK DS-UWB). In this paper, adaptive multiple antenna transmission scheme for achieving high capacity and reliability in M-BOK DS-UWB is proposed. This proposed system can overcome the limitations of STBC and V-BLAST, such as bit error rate performance and throughput.
Still Image Watermarking in the DCT Domain Using the Human Visual System
Kwon O-Hyung ; Park Rae-Hong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1214~1221
In this paper, we propose a digital watermarking method for still images, in which the human visual system (HVS) is used in the discrete cosine transform (DCT) domain. The modulation transfer function (MTF) of the HVS model is employed to increase the invisibility of the inserted watermark in images. The proposed watermarking method is shown to be robust to several common image processing techniques, including lowpass filtering and cropping. Also, using the energy relationship of the DCT, we derive the equation that directly computes the watermark weighting factor in the DCT domain for the specified peak signal to noise ratio (PSNR) of the still image and the length of watermark to be inserted. The difference between desired PSNR and PSNR in spatial domain is within 0.07dB for the 7 test images.
Efficient Hybrid ARQ with Space-Time Coding and Low-Complexity Decoding
Oh Mi-Kyung ; Kwon Yeong-Hyen ; Park Dong-Jo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1222~1230
We aim at increasing the throughput of the hybrid automatic retransmission request (HARQ) protocol in Space-Time (ST) coded multi-antenna transmission systems. By utilizing reliability information at the decoder, we obtain an improved probability of successful decoding, which enhances the overall system throughput at low-complexity. Simulations and analytical results demonstrate the performance of our scheme in impulse noise environment as well as AWGN and fading multi-input multi-ouput (MIMO) channels.
A Fast Encoding Algorithm for Image Vector Quantization Based on Prior Test of Multiple Features
Ryu Chul-hyung ; Ra Sung-woong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1231~1238
This paper presents a new fast encoding algorithm for image vector quantization that incorporates the partial distances of multiple features with a multidimensional look-up table (LUT). Although the methods which were proposed earlier use the multiple features, they handles the multiple features step by step in terms of searching order and calculating process. On the other hand, the proposed algorithm utilizes these features simultaneously with the LUT. This paper completely describes how to build the LUT with considering the boundary effect for feasible memory cost and how to terminate the current search by utilizing partial distances of the LUT Simulation results confirm the effectiveness of the proposed algorithm. When the codebook size is 256, the computational complexity of the proposed algorithm can be reduced by up to the
of the operations required by the recently proposed alternatives such as the ordered Hadamard transform partial distance search (OHTPDS), the modified
), etc. With feasible preprocessing time and memory cost, the proposed algorithm reduces the computational complexity to below the
of those required for the exhaustive full search (EFS) algorithm while preserving the same encoding quality as that of the EFS algorithm.
Performance Lmprovements of Self-Similar Traffic Congestion Control of Multiple Time Scale Under in TCP-MT network
Na Ha-Sun ; Kim Moon-Hwan ; Ra Sang-Dong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1239~1247
It is important to improve TCP performance in Self-similar TCP network where signalling between the same end nodes through bidirectional traffic routes. In wireless link, the traffic limitation pattern occurred in two or more TCP connections is applied into MPEC video control as multi time-interval congestion control. For TCP update variable, we extend TCP and perform as function call, and we study a method of relating TCP with LTS module controlling with the information type that is overcoming the limit of feedback loop determined by RTT. For comparison, we measure the TCP throughput without LTS and verify the fairness by means of meta control. The improved TCP performance is shown by that the number of connections of traffic congestion control increases when RTT increases.
Phase Noise Analysis and Suppression Algorithm for OFDM-Based 60GHz WLANs
Kim Han-Kyong ; Ahn Kyung-Seung ; Baik Heung-Ki ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1248~1255
We investigate the OFDM-based wireless LAN systems operating in the 60 GHz frequency band as part of the fourth-generation (4G) systems. The 60 GHz band is of much interest since this is the band in which a massive amount of spectral space has been allocated worldwide for dense wireless local communications. This paper gives an overview of 60 GHz bandchannel characteristics and an effect on phase noise. The performance of OFDM system is severely degraded by the local oscillator phase noise, which causes both common phase error and inter-carrier interference. In this paper, we apply phase noise suppression (PNS) algorithm that is easy for implementation to OFDM based 60 GHz wireless LAM system and analyze the SER performance. In case of using the PNS algorithm, SER performance is improved about 6dB, 7.5dB, respectively in 16, 64-QAM
Fast Motion Estimation Algorithm Using Motion Vectors of Neighboring Blocks
So Hyeon-Ho ; Kim Jinsang ; Cho Won-Kyung ; Kim Young-Soo ; Suh Doug Young ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1256~1261
In this paper, we propose a low-power Booth multiplication which reduces the switching activities of partial products during multiplication process. Radix-4 Booth algorithm has a characteristic that produces the Booth encoded products with zero when input data have sequentially equal values (0 or 1). Therefore, partial products have higher chances of being zero when an input with a smaller effective dynamic range of two multiplication inputs is used as a multiplier data instead of a multiplicand. The proposed multiplier divides a multiplication expression into several multiplication expressions with smaller bits than those of an original input data, and each multiplication is computed independently for the Booth encoding. Finally, the results of each multiplication are added. This means that the proposed multiplier has a higher chance to have zero encoded products so that we can implement a low power multiplier with the smaller switching activity. Implementation results show the proposed multiplier can save maximally about
power dissipation than a previous Booth multiplier.
VAD By Neural Network Under Wireless Communication Systems
Lee Hosun ; Kim Sukyung ; Park Sung-Kwon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 12C, 2005, Pages 1262~1267
Elliptical basis function (EBF) neural network works stably under high-level background noise environment and makes the nonlinear processing possible. It can be adapted real time VAD with simple design. This paper introduces VAD implementation using EBF and the experimental results show that EBF VAD outperforms G729 Annex B and RBF neural networks. The best error rates achieved by the EBF networks were improved more than
in speech and
in silence while that achieved by G.729 Annex B and RBF networks respectively.