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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 33, Issue 6 - Dec 2011
Volume 33, Issue 5 - Oct 2011
Volume 33, Issue 4 - Aug 2011
Volume 33, Issue 3 - Jun 2011
Volume 33, Issue 2 - Apr 2011
Volume 33, Issue 1 - Feb 2011
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Highly Efficient Video Codec for Entertainment-Quality
Jeong, Se-Yoon ; Lim, Sung-Chang ; Lee, Ha-Hyun ; Kim, Jong-Ho ; Choi, Jin-Soo ; Choi, Hae-Chul ;
ETRI Journal, volume 33, issue 2, 2011, Pages 145~154
DOI : 10.4218/etrij.11.0110.0126
We present a novel video codec for supporting entertainment-quality video. It has new coding tools such as an intra prediction with offset, integer sine transform, and enhanced block-based adaptive loop filter. These tools are used adaptively in the processing of intra prediction, transform, and loop filtering. In our experiments, the proposed codec achieved an average reduction of 13.35% in BD-rate relative to H.264/AVC for 720p sequences.
Joint Source/Channel Coding Based on Two-Dimensional Optimization for Scalable H.264/AVC Video
Li, Xiao-Feng ; Zhou, Ning ; Liu, Hong-Sheng ;
ETRI Journal, volume 33, issue 2, 2011, Pages 155~162
DOI : 10.4218/etrij.11.0110.0220
The scalable extension of the H.264/AVC video coding standard (SVC) demonstrates superb adaptability in video communications. Joint source and channel coding (JSCC) has been shown to be very effective for such scalable video consisting of parts of different significance. In this paper, a new JSCC scheme for SVC transmission over packet loss channels is proposed which performs two-dimensional optimization on the quality layers of each frame in a rate-distortion (R-D) sense as well as on the temporal hierarchical structure of frames under dependency constraints. To compute the end-to-end R-D points of a frame, a novel reduced trellis algorithm is developed with a significant reduction of complexity from the existing Viterbi-based algorithm. The R-D points of frames are sorted under the hierarchical dependency constraints and optimal JSCC solution is obtained in terms of the best R-D performance. Experimental results show that our scheme outperforms the existing scheme of  with average quality gains of 0.26 dB and 0.22 dB for progressive and non-progressive modes respectively.
Design Method of a Circularly-Polarized Antenna Using Fabry-Perot Cavity Structure
Ju, Jeong-Ho ; Kim, Dong-Ho ; Lee, Wang-Joo ; Choi, Jae-Ick ;
ETRI Journal, volume 33, issue 2, 2011, Pages 163~168
DOI : 10.4218/etrij.11.0110.0267
A Fabry-Perot cavity (FPC) antenna producing both high-gain and circularly-polarized (CP) behavior is proposed. To increase antenna gain and obtain CP characteristics, a superstrate composed of square patches with a pair of truncated corners is placed above the linearly polarized patch antenna with an approximately half-wavelength distance from the ground plane at the operating frequency. The proposed antenna has the advantages of high gain, a simple design, and an excellent boresight axial ratio over the operating frequency bandwidth. Moreover, used in an FPC antenna, the proposed superstrate converts a linear polarization produced by a patch antenna into a circular polarization. In addition, the cavity antenna produces left-hand circular-polarization and right-hand circular-polarization when a patch antenna inside the cavity generates x-direction and y-direction polarization, respectively. The measured and simulated results verify the performance of the antenna.
Double-Sharpened Decimation Filter Employing a Pre-droop Compensator for Multistandard Wireless Applications
Jeong, Chan-Yong ; Min, Young-Jae ; Kim, Soo-Won ;
ETRI Journal, volume 33, issue 2, 2011, Pages 169~175
DOI : 10.4218/etrij.11.0110.0272
This paper presents a double-sharpened decimation filter based on the application of a Kaiser and Hamming sharpening technique for multistandard wireless systems. The proposed double-sharpened decimation filter uses a pre-droop compensator which improves the passband response of a conventional cascaded integrator-comb filter so that it provides an efficient sharpening performance at half-speed with comparison to conventional sharpened filters. In this paper, the passband droop characteristics with compensation provides -1.6 dB for 1.25 MHz, -1.4 dB for 2.5 MHz, -1.3 dB for 5 MHz, and -1.0 dB for 10 MHz bandwidths, respectively. These results demonstrate that the proposed double-sharpened decimation filter is suitable for multistandard wireless applications.
Improvement of Noise Performance in Phased-Array Receivers
Kim, Jung-Hyun ; Jeong, Jin-Ho ; Jeon, Sang-Geun ;
ETRI Journal, volume 33, issue 2, 2011, Pages 176~183
DOI : 10.4218/etrij.11.0110.0440
This paper presents a new analytical approach and experimental verification for the improvement of noise performance in phased-array receivers. For analysis purposes, a multi-channel array system is converted into an equivalent single-channel system, such that the two presents the identical signal and noise powers at the output, respectively. We define an effective gain, noise figure, and signal-to-noise ratio in the equivalent system. Through the proposed approach, the noise performance of the array receiver is analyzed in a general and straightforward manner and then compared to that of each individual array channel. In addition, the phase noise of the array system is analyzed in a rigorous manner, showing its effective reduction by a factor of the array size. The predicted improvement of the noise performance is experimentally confirmed with a CMOS integrated phased-array receiver.
Cross-Layer Resource Allocation Scheme for WLANs with Multipacket Reception
Xu, Lei ; Xu, Dazhuan ; Zhang, Xiaofei ; Xu, Shufang ;
ETRI Journal, volume 33, issue 2, 2011, Pages 184~193
DOI : 10.4218/etrij.11.0110.0258
Tailored for wireless local area networks, the present paper proposes a cross-layer resource allocation scheme for multiple-input multiple-output orthogonal frequency-division multiplexing systems. Our cross-layer resource allocation scheme consists of three stages. Firstly, the condition of sharing the subchannel by more than one user is studied. Secondly, the subchannel allocation policy which depends on the data packets' lengths and the admissible combination of users per subchannel is proposed. Finally, the bits and corresponding power are allocated to users based on a greedy algorithm and the data packets' lengths. The analysis and simulation results demonstrate that our proposed scheme not only achieves significant improvement in system throughput and average packet delay compared with conventional schemes but also has low computational complexity.
Improved Method for the Macroblock-Level Deblocking Scheme
Le, Thanh Ha ; Jung, Seung-Won ; Baek, Seung-Jin ; Ko, Sung-Jea ;
ETRI Journal, volume 33, issue 2, 2011, Pages 194~200
DOI : 10.4218/etrij.11.0110.0205
This paper presents a deblocking method for video compression in which the blocking artifacts are effectively extracted and eliminated based on both spatial and frequency domain operations. Firstly, we use a probabilistic approach to analyze the performance of the conventional macroblock-level deblocking scheme. Then, based on the results of the analysis, an algorithm to reduce the computational complexity is introduced. Experimental results show that the proposed algorithm outperforms the conventional video coding methods in terms of computation complexity while coding efficiency is maintained.
Wide-Band Fine-Resolution DCO with an Active Inductor and Three-Step Coarse Tuning Loop
Pu, Young-Gun ; Park, An-Soo ; Park, Joon-Sung ; Moon, Yeon-Kug ; Kim, Su-Ki ; Lee, Kang-Yoon ;
ETRI Journal, volume 33, issue 2, 2011, Pages 201~209
DOI : 10.4218/etrij.11.0110.0209
This paper presents a wide-band fine-resolution digitally controlled oscillator (DCO) with an active inductor using an automatic three-step coarse and gain tuning loop. To control the frequency of the DCO, the transconductance of the active inductor is tuned digitally. To cover the wide tuning range, a three-step coarse tuning scheme is used. In addition, the DCO gain needs to be calibrated digitally to compensate for gain variations. The DCO tuning range is 58% at 2.4 GHz, and the power consumption is 6.6 mW from a 1.2 V supply voltage. An effective frequency resolution is 0.14 kHz. The phase noise of the DCO output at 2.4 GHz is -120.67 dBc/Hz at 1 MHz offset.
Conditional Mutual Information-Based Feature Selection Analyzing for Synergy and Redundancy
Cheng, Hongrong ; Qin, Zhiguang ; Feng, Chaosheng ; Wang, Yong ; Li, Fagen ;
ETRI Journal, volume 33, issue 2, 2011, Pages 210~218
DOI : 10.4218/etrij.11.0110.0237
Battiti's mutual information feature selector (MIFS) and its variant algorithms are used for many classification applications. Since they ignore feature synergy, MIFS and its variants may cause a big bias when features are combined to cooperate together. Besides, MIFS and its variants estimate feature redundancy regardless of the corresponding classification task. In this paper, we propose an automated greedy feature selection algorithm called conditional mutual information-based feature selection (CMIFS). Based on the link between interaction information and conditional mutual information, CMIFS takes account of both redundancy and synergy interactions of features and identifies discriminative features. In addition, CMIFS combines feature redundancy evaluation with classification tasks. It can decrease the probability of mistaking important features as redundant features in searching process. The experimental results show that CMIFS can achieve higher best-classification-accuracy than MIFS and its variants, with the same or less (nearly 50%) number of features.
Transformation Approach to Model Online Gaming Traffic
Shin, Kwang-Sik ; Kim, Jin-Hyuk ; Sohn, Kang-Min ; Park, Chang-Joon ; Choi, Sang-Bang ;
ETRI Journal, volume 33, issue 2, 2011, Pages 219~229
DOI : 10.4218/etrij.11.1510.0087
In this paper, we propose a transformation scheme used to analyze online gaming traffic properties and develop a traffic model. We analyze the packet size and the inter departure time distributions of a popular first-person shooter game (Left 4 Dead) and a massively multiplayer online role-playing game (World of Warcraft) in order to compare them to the existing scheme. Recent online gaming traffic is erratically distributed, so it is very difficult to analyze. Therefore, our research focuses on a transformation scheme to obtain new smooth patterns from a messy dataset. It extracts relatively heavy-weighted density data and then transforms them into a corresponding dataset domain to obtain a simplified graph. We compare the analytical model histogram, the chi-square statistic, and the quantile-quantile plot of the proposed scheme to an existing scheme. The results show that the proposed scheme demonstrates a good fit in all parts. The chi-square statistic of our scheme for the Left 4 Dead packet size distribution is less than one ninth of the existing one when dealing with erratic traffic.
Improving Memory Efficiency of Dynamic Memory Allocators for Real-Time Embedded Systems
Lee, Jung-Hee ; Yi, Joon-Hwan ;
ETRI Journal, volume 33, issue 2, 2011, Pages 230~239
DOI : 10.4218/etrij.11.0110.0268
Dynamic memory allocators for real-time embedded systems need to fulfill three fundamental requirements: bounded worst-case execution time, fast average execution time, and minimal fragmentation. Since embedded systems generally run continuously during their whole lifetime, fragmentation is one of the most important factors in designing the memory allocator. This paper focuses on minimizing fragmentation while other requirements are still satisfied. To minimize fragmentation, a part of a memory region is segregated by the proposed budgeting method that exploits the memory profile of the given application. The budgeting method can be applied for any existing memory allocators. Experimental results show that the memory efficiency of allocators can be improved by up to 18.85% by using the budgeting method. Its worst-case execution time is analyzed to be bounded.
Content-Based Image Retrieval Based on Relevance Feedback and Reinforcement Learning for Medical Images
Lakdashti, Abolfazl ; Ajorloo, Hossein ;
ETRI Journal, volume 33, issue 2, 2011, Pages 240~250
DOI : 10.4218/etrij.11.0110.0203
To enable a relevance feedback paradigm to evolve itself by users' feedback, a reinforcement learning method is proposed. The feature space of the medical images is partitioned into positive and negative hypercubes by the system. Each hypercube constitutes an individual in a genetic algorithm infrastructure. The rules take recombination and mutation operators to make new rules for better exploring the feature space. The effectiveness of the rules is checked by a scoring method by which the ineffective rules will be omitted gradually and the effective ones survive. Our experiments on a set of 10,004 images from the IRMA database show that the proposed approach can better describe the semantic content of images for image retrieval with respect to other existing approaches in the literature.
Tiny and Blurred Face Alignment for Long Distance Face Recognition
Ban, Kyu-Dae ; Lee, Jae-Yeon ; Kim, Do-Hyung ; Kim, Jae-Hong ; Chung, Yun-Koo ;
ETRI Journal, volume 33, issue 2, 2011, Pages 251~258
DOI : 10.4218/etrij.11.1510.0022
Applying face alignment after face detection exerts a heavy influence on face recognition. Many researchers have recently investigated face alignment using databases collected from images taken at close distances and with low magnification. However, in the cases of home-service robots, captured images generally are of low resolution and low quality. Therefore, previous face alignment research, such as eye detection, is not appropriate for robot environments. The main purpose of this paper is to provide a new and effective approach in the alignment of small and blurred faces. We propose a face alignment method using the confidence value of Real-AdaBoost with a modified census transform feature. We also evaluate the face recognition system to compare the proposed face alignment module with those of other systems. Experimental results show that the proposed method has a high recognition rate, higher than face alignment methods using a manually-marked eye position.
Automated Markerless Analysis of Human Gait Motion for Recognition and Classification
Yoo, Jang-Hee ; Nixon, Mark S. ;
ETRI Journal, volume 33, issue 2, 2011, Pages 259~266
DOI : 10.4218/etrij.11.1510.0068
We present a new method for an automated markerless system to describe, analyze, and classify human gait motion. The automated system consists of three stages: I) detection and extraction of the moving human body and its contour from image sequences, ii) extraction of gait figures by the joint angles and body points, and iii) analysis of motion parameters and feature extraction for classifying human gait. A sequential set of 2D stick figures is used to represent the human gait motion, and the features based on motion parameters are determined from the sequence of extracted gait figures. Then, a k-nearest neighbor classifier is used to classify the gait patterns. In experiments, this provides an alternative estimate of biomechanical parameters on a large population of subjects, suggesting that the estimate of variance by marker-based techniques appeared generous. This is a very effective and well-defined representation method for analyzing the gait motion. As such, the markerless approach confirms uniqueness of the gait as earlier studies and encourages further development along these lines.
Efficient Masked Implementation for SEED Based on Combined Masking
Kim, Hee-Seok ; Cho, Young-In ; Choi, Doo-Ho ; Han, Dong-Guk ; Hong, Seok-Hie ;
ETRI Journal, volume 33, issue 2, 2011, Pages 267~274
DOI : 10.4218/etrij.11.1510.0112
This paper proposes an efficient masking method for the block cipher SEED that is standardized in Korea. The nonlinear parts of SEED consist of two S-boxes and modular additions. However, the masked version of these nonlinear parts requires excessive RAM usage and a large number of operations. Protecting SEED by the general masking method requires 512 bytes of RAM corresponding to masked S-boxes and a large number of operations corresponding to the masked addition. This paper proposes a new-style masked S-box which can reduce the amount of operations of the masking addition process as well as the RAM usage. The proposed masked SEED, equipped with the new-style masked S-box, reduces the RAM requirements to 288 bytes, and it also reduces the processing time by 38% compared with the masked SEED using the general masked S-box. The proposed method also applies to other block ciphers with the same nonlinear operations.
Thermo-Optic Digital Optical Switch Based on the Total-Internal-Reflection Effect
Han, Young-Tak ; Shin, Jang-Uk ; Park, Sang-Ho ; Han, Sang-Pil ; Baek, Yong-Soon ; Lee, Chul-Hee ; Noh, Young-Ouk ; Park, Hyo-Hoon ;
ETRI Journal, volume 33, issue 2, 2011, Pages 275~278
DOI : 10.4218/etrij.11.0210.0380
This letter presents a polymer
thermo-optic totalinternal-reflection digital optical switch (TIR-DOS) with an index contrast of 1.5%-
operating at low power consumption. The structure of our
TIR-DOS was created by adding a reflection port to that of a conventional multimode filtering variable optical attenuator. To improve the total-internalr-eflection efficiency, a heater offset was applied to the crossing region of multimode waveguides of the TIR-DOS. The fabricated
TIR-DOS shows a low electrical power consumption of 18 mW for an on-off ratio of 35 dB.
Coexistence of OFDM-Based IMT-Advanced and FM Broadcasting Systems
Shamsan, Zaid A. ; Rahman, Tharek A. ; Kamarudin, Muhammad R. ; Al-Hetar, Abdulaziz M. ; Jo, Han-Shin ;
ETRI Journal, volume 33, issue 2, 2011, Pages 279~282
DOI : 10.4218/etrij.11.0210.0211
Coexistence analysis is extremely important in examining the possibility for spectrum sharing between orthogonal frequency-division multiplexing (OFDM)-based international mobile telecommunications (IMT)-Advanced and other wireless services. In this letter, a new closed form method is derived based on power spectral density analysis in order to analyze the coexistence of OFDM-based IMT-Advanced systems and broadcasting frequency modulation (FM) systems. The proposed method evaluates more exact interference power of IMT-Advanced systems in FM broadcasting systems than the advanced minimum coupling loss (A-MCL) method. Numerical results show that the interference power is 1.3 dB and 3 dB less than that obtained using the A-MCL method at cochannel and adjacent channel, respectively. This reduces the minimum separation distance between the two systems, which eventually saves spectrum resources.
Distribution of Path Loss for Wireless Personal Networks Operating in a Square Region
Yang, Rumin ; Shen, Bin ; Kwak, Kyung-Sup ;
ETRI Journal, volume 33, issue 2, 2011, Pages 283~286
DOI : 10.4218/etrij.11.0210.0218
Path loss plays fundamental roles in system design, spectrum management, and performance evaluation. The traditional path loss model has a slight inconvenience; it depends on the unknown distance. In this letter, we explore the probability distribution function (PDF) of path loss in an indoor office environment by randomizing out the distance variable. It is shown that the resulting PDF is not Gaussian-like but is skewed to the right, and both the PDF and the moments are related to the size of the office instead of the unknown distance. To be specific, we incorporate the IEEE 802.15.4a channel parameters into our model and tabulate the cumulative distribution function with respect to different room sizes. Through a simple example, we show how our model helps a cognitive spectrum user to infer path loss information of primary users without necessarily knowing their transmitter-receiver distance.
Opportunistic Decode-and-Forward Cooperation in Mixed Rayleigh and Rician Fading Channels
Yang, Changqing ; Wang, Wenbo ; Zhao, Shuang ; Peng, Mugen ;
ETRI Journal, volume 33, issue 2, 2011, Pages 287~290
DOI : 10.4218/etrij.11.0210.0219
We consider a two-hop multiple-relay network implemented with opportunistic decode-and-forward cooperative strategy, where the first hop and second hop links experience different fading (Rayleigh and Rician). We derive the exact expressions of end-to-end outage probability and analyze the approximate results in high signal-to-noise ratio region. The analysis shows that the same diversity order can be achieved even in different mixed fading environments. Simulation results are provided to verify our analysis.
Open-Ended Waveguide Antenna Using a Single Split-Ring Resonator
Ju, Young-Rim ; Oh, Soon-Soo ; Park, Wook-Ki ; Park, Hyo-Dal ;
ETRI Journal, volume 33, issue 2, 2011, Pages 291~294
DOI : 10.4218/etrij.11.0210.0193
This letter proposes an open-ended waveguide antenna with a single split-ring resonator. In contrast to the waveguide antennas incorporating multiple rings reported in a previous study, which exhibited narrow bandwidth, the proposed antenna uses only one ring to achieve broader bandwidth while keeping the aperture small. A single ring has a relatively low quality factor compared to multiple rings. The simulated and measured fractional bandwidth was 4.13% and 4.03%, respectively, which is much broader than the fractional bandwidth of about 1% demonstrated in a previous study. This simple technique can be used in many applications that require small apertures including near-field probes and array elements.
Motion-Compensated Frame Interpolation Using a Parabolic Motion Model and Adaptive Motion Vector Selection
Choi, Kang-Sun ; Hwang, Min-Chul ;
ETRI Journal, volume 33, issue 2, 2011, Pages 295~298
DOI : 10.4218/etrij.11.0210.0203
We propose a motion-compensated frame interpolation method in which an accurate backward/forward motion vector pair (MVP) is estimated based on a parabolic motion model. A reliability measure for an MVP is also proposed to select the most reliable MVP for each interpolated block. The possibility of deformation of bidirectional corresponding blocks is estimated from the selected MVP. Then, each interpolated block is produced by combining corresponding blocks with the weights based on the possibility of deformation. Experimental results show that the proposed method improves PSNR performance by up to 2.8 dB as compared to conventional methods and achieves higher visual quality without annoying blockiness artifacts.