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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 32, Issue 6 - Dec 2010
Volume 32, Issue 5 - Oct 2010
Volume 32, Issue 4 - Aug 2010
Volume 32, Issue 3 - Jun 2010
Volume 32, Issue 2 - Apr 2010
Volume 32, Issue 1 - Feb 2010
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A Low-Complexity Planar Antenna Array for Wireless Communication Applications: Robust Source Localization in Impulsive Noise
Lee, Moon-Sik ;
ETRI Journal, volume 32, issue 6, 2010, Pages 837~842
DOI : 10.4218/etrij.10.0109.0748
This paper proposes robust source localization methods for estimating the azimuth angle, elevation angle, velocity, and range using a low-complexity planar antenna array in impulsive non-Gaussian noise environments. The proposed robust source localization methods for wireless communication applications are based on nonlinear M-estimation provided from Huber and Hampel. Simulation results show the robustness performance of the proposed robust methods in impulsive non-Gaussian noise.
Statistical Analysis of a Subjective QoE Assessment for VVoIP Applications
Cano, Maria-Dolores ; Cerdan, Fernando ; Almagro, Sergio ;
ETRI Journal, volume 32, issue 6, 2010, Pages 843~853
DOI : 10.4218/etrij.10.0109.0645
A successful deployment of multimedia applications over wireless environments entails improving the quality of service (QoS), not only from a technical point of view, but also considering the quality of experience (QoE) from the final user's perception. Although objective QoE measure models avoid the difficulties of subjective surveys, subjective QoE assessments are essential to understand the way users evaluate the QoS. In this work, we study the effect of a wide range of parameters on the QoE of VVoIP applications in a real wireless scenario. Through a complete statistical analysis of users' ratings, we identify the following facts. Although the use of VVoIP in wireless networks does not yet represent an advantage for users, there are great expectations for all applications under study, and with greater popularity comes higher expectations. It is easier for respondents to identify good behavior than poor behavior. Whereas the respondents' frequency of Internet use does not impact on the scores, respondents' gender does. Finally, the most determining parameters of quality from a user's perspective were instability, video quality, voice distortion, usefulness, and graphical interface.
Measurement Scheme for One-Way Delay Variation with Detection and Removal of Clock Skew
Aoki, Makoto ; Oki, Eiji ; Rojas-Cessa, Roberto ;
ETRI Journal, volume 32, issue 6, 2010, Pages 854~862
DOI : 10.4218/etrij.10.0109.0611
One-way delay variation (OWDV) has become increasingly of interest to researchers as a way to evaluate network state and service quality, especially for real-time and streaming services such as voice-over-Internet-protocol (VoIP) and video. Many schemes for OWDV measurement require clock synchronization through the global-positioning system (GPS) or network time protocol. In clock-synchronized approaches, the accuracy of OWDV measurement depends on the accuracy of the clock synchronization. GPS provides highly accurate clock synchronization. However, the deployment of GPS on legacy network equipment might be slow and costly. This paper proposes a method for measuring OWDV that dispenses with clock synchronization. The clock synchronization problem is mainly caused by clock skew. The proposed approach is based on the measurement of inter-packet delay and accumulated OWDV. This paper shows the performance of the proposed scheme via simulations and through experiments in a VoIP network. The presented simulation and measurement results indicate that clock skew can be efficiently measured and removed and that OWDV can be measured without requiring clock synchronization.
Reducing Channel Capacity for Scalable Video Coding in a Distributed Network
Kim, Hyun-Pil ; Lee, Suk-Han ; Lee, Jung-Hee ; Lee, Yong-Surk ;
ETRI Journal, volume 32, issue 6, 2010, Pages 863~870
DOI : 10.4218/etrij.10.0110.0033
In recent years, the development of multimedia devices has meant that a wider multimedia streaming service can be supported, and there are now many ways in which TV channels can communicate with different terminals. Generally, scalable video streaming is known to provide more efficient channel capacity than simulcast video streaming. Simulcast video streaming requires a large network bandwidth for all resolutions, but scalable video streaming needs only one flow for all resolutions. In previous research, scalable video streaming has been compared with simulcast video streaming for network channel capacity, in two user simulation environments. The simulation results show that the channel capacity of SVC is 16% to 20% smaller than AVC, but scalable video streaming is not efficient because of the limit of the present network framework. In this paper, we propose a new network framework with an SVC extractor. The proposed network framework shows a channel capacity 50% (maximum) lower than that found in previous research studies.
Concentric Circle-Based Image Signature for Near-Duplicate Detection in Large Databases
Cho, A-Young ; Yang, Won-Keun ; Oh, Weon-Geun ; Jeong, Dong-Seok ;
ETRI Journal, volume 32, issue 6, 2010, Pages 871~880
DOI : 10.4218/etrij.10.0109.0623
Many applications dealing with image management need a technique for removing duplicate images or for grouping related (near-duplicate) images in a database. This paper proposes a concentric circle-based image signature which makes it possible to detect near-duplicates rapidly and accurately. An image is partitioned by radius and angle levels from the center of the image. Feature values are calculated using the average or variation between the partitioned sub-regions. The feature values distributed in sequence are formed into an image signature by hash generation. The hashing facilitates storage space reduction and fast matching. The performance was evaluated through discriminability and robustness tests. Using these tests, the particularity among the different images and the invariability among the modified images are verified, respectively. In addition, we also measured the discriminability and robustness by the distribution analysis of the hashed bits. The proposed method is robust to various modifications, as shown by its average detection rate of 98.99%. The experimental results showed that the proposed method is suitable for near-duplicate detection in large databases.
Fast and Efficient Method for Fire Detection Using Image Processing
Celik, Turgay ;
ETRI Journal, volume 32, issue 6, 2010, Pages 881~890
DOI : 10.4218/etrij.10.0109.0695
Conventional fire detection systems use physical sensors to detect fire. Chemical properties of particles in the air are acquired by sensors and are used by conventional fire detection systems to raise an alarm. However, this can also cause false alarms; for example, a person smoking in a room may trigger a typical fire alarm system. In order to manage false alarms of conventional fire detection systems, a computer vision-based fire detection algorithm is proposed in this paper. The proposed fire detection algorithm consists of two main parts: fire color modeling and motion detection. The algorithm can be used in parallel with conventional fire detection systems to reduce false alarms. It can also be deployed as a stand-alone system to detect fire by using video frames acquired through a video acquisition device. A novel fire color model is developed in CIE
color space to identify fire pixels. The proposed fire color model is tested with ten diverse video sequences including different types of fire. The experimental results are quite encouraging in terms of correctly classifying fire pixels according to color information only. The overall fire detection system's performance is tested over a benchmark fire video database, and its performance is compared with the state-of-the-art fire detection method.
New Map-Matching Algorithm Using Virtual Track for Pedestrian Dead Reckoning
Shin, Seung-Hyuck ; Park, Chan-Gook ; Choi, Sang-On ;
ETRI Journal, volume 32, issue 6, 2010, Pages 891~900
DOI : 10.4218/etrij.10.0110.0037
In this paper, a map-matching (MM) algorithm which combines an estimated position with digital road data is proposed. The presented algorithm using a virtual track is appropriate for a MEMS-based pedestrian dead reckoning (PDR) system, which can be used in mobile devices. Most of the previous MM algorithms are for car navigation systems and GPS-based navigation system, so existing MM algorithms are not appropriate for the pure DR-based pedestrian navigation system. The biggest problem of previous MM algorithms is that they cannot determine the correct road segment (link) due to the DR characteristics. In DR-based navigation system, the current position is propagated from the previous estimated position. This means that the MM result can be placed on a wrong link when MM algorithm fails to decide the correct link at once. It is a critical problem. Previous algorithms never overcome this problem because they did not consider pure DR characteristics. The MM algorithm using the virtual track is proposed to overcome this problem with improved accuracy. Performance of the proposed MM algorithm was verified by experiments.
Preclinical Prototype Development of a Microwave Tomography System for Breast Cancer Detection
Son, Seong-Ho ; Simonov, Nikolai ; Kim, Hyuk-Je ; Lee, Jong-Moon ; Jeon, Soon-Ik ;
ETRI Journal, volume 32, issue 6, 2010, Pages 901~910
DOI : 10.4218/etrij.10.0109.0626
As a supplement to X-ray mammography, microwave imaging is a new and promising technique for breast cancer detection. Through solving the nonlinear inverse scattering problem, microwave tomography (MT) creates images from measured signals using antennas. In this paper, we describe a developed MT system and an iterative Gauss-Newton algorithm. At each iteration, this algorithm determines the updated values by solving the set of normal equations using Tikhonov regularization. Some examples of successful image reconstruction are presented.
A Design Method of Hybrid Analog/Asymmetrical-FIR Pulse-Shaping Filters with an Eye-Opening Control Option against Receiver Timing Jitter
Yao, Chia-Yu ;
ETRI Journal, volume 32, issue 6, 2010, Pages 911~920
DOI : 10.4218/etrij.10.0109.0725
This paper presents a method of designing hybrid analog/asymmetrical square-root (SR) FIR filters. In addition to the conventional frequency domain constraints, the proposed method considers time-domain constraints as well, including the inter-symbol interference (ISI) and the opening of the eye pattern at the receiver output. This paper also reviews a systematic way to find the discrete-time equivalence of analog parts in a band-limited digital communication system. Thus, a phase equalizer can be easily realized to compensate for the nonlinear phase responses of the analog components. With the hybrid analog/SR FIR filter co-design, examples show that using the proposed method can result in a more robust ISI performance in the presence of the receiver clock jitter.
Interference Suppression Using Principal Subspace Modification in Multichannel Wiener Filter and Its Application to Speech Recognition
Kim, Gi-Bak ;
ETRI Journal, volume 32, issue 6, 2010, Pages 921~931
DOI : 10.4218/etrij.10.0110.0045
It has been shown that the principal subspace-based multichannel Wiener filter (MWF) provides better performance than the conventional MWF for suppressing interference in the case of a single target source. It can efficiently estimate the target speech component in the principal subspace which estimates the acoustic transfer function up to a scaling factor. However, as the input signal-to-interference ratio (SIR) becomes lower, larger errors are incurred in the estimation of the acoustic transfer function by the principal subspace method, degrading the performance in interference suppression. In order to alleviate this problem, a principal subspace modification method was proposed in previous work. The principal subspace modification reduces the estimation error of the acoustic transfer function vector at low SIRs. In this work, a frequency-band dependent interpolation technique is further employed for the principal subspace modification. The speech recognition test is also conducted using the Sphinx-4 system and demonstrates the practical usefulness of the proposed method as a front processing for the speech recognizer in a distant-talking and interferer-present environment.
Optimized Local Relocation for VLSI Circuit Modification Using Mean-Field Annealing
Karimi, Gholam Reza ; Verki, Ahmad Azizi ; Mirzakuchaki, Sattar ;
ETRI Journal, volume 32, issue 6, 2010, Pages 932~939
DOI : 10.4218/etrij.10.0109.0533
In this paper, a fast migration method is proposed. Our method executes local relocation on a model placement where an additional module is added to it for modification with a minimum number of displacements. This method is based on mean-field annealing (MFA), which produces a solution as reliable as a previously used method called simulated annealing. The proposed method requires substantially less time and hardware, and it is less sensitive to the initial and final temperatures. In addition, the solution runtime is mostly independent of the size and complexity of the input model placement. Our proposed MFA algorithm is optimized by enabling module rotation inside an energy function called permissible distances preservation energy. This, in turn, allows more options in moving the engaged modules. Finally, a three-phase cooling process governs the convergence of problem variables called neurons or spins.
Rack-Level DC Power Solution for Volume Servers
Kwon, Won-Ok ; Seo, Hae-Moon ; Choi, Pyung ;
ETRI Journal, volume 32, issue 6, 2010, Pages 940~949
DOI : 10.4218/etrij.10.1510.0060
Rack-level DC power supply is the optimal technology for providing DC power to a volume server without any power infrastructure changes in an existing AC data center. In this paper, we propose a smartly controllable and monitorable DC rack power system. The proposed system improves power efficiency by changing the power distribution architecture of a conventional method in the rack. We developed an optimal power control method in multipower modules to provide high efficiency at low loads. In addition, the proposed system provides real-time web monitoring of the rack power and environment around a rack. In our experiments, the proposed system improved the power efficiency by over 10% compared to an AC power system providing N+1 redundant power and power monitoring.
Secure Face Authentication Framework in Open Networks
Lee, Yong-Jin ; Lee, Yong-Ki ; Chung, Yun-Su ; Moon, Ki-Young ;
ETRI Journal, volume 32, issue 6, 2010, Pages 950~960
DOI : 10.4218/etrij.10.1510.0103
In response to increased security concerns, biometrics is becoming more focused on overcoming or complementing conventional knowledge and possession-based authentication. However, biometric authentication requires special care since the loss of biometric data is irrecoverable. In this paper, we present a biometric authentication framework, where several novel techniques are applied to provide security and privacy. First, a biometric template is saved in a transformed form. This makes it possible for a template to be canceled upon its loss while the original biometric information is not revealed. Second, when a user is registered with a server, a biometric template is stored in a special form, named a 'soft vault'. This technique prevents impersonation attacks even if data in a server is disclosed to an attacker. Finally, a one-time template technique is applied in order to prevent replay attacks against templates transmitted over networks. In addition, the whole scheme keeps decision equivalence with conventional face authentication, and thus it does not decrease biometric recognition performance. As a result, the proposed techniques construct a secure face authentication framework in open networks.
Efficient Multiplexing Scheme of Stereoscopic Video Sequences for Digital Broadcasting Services
Yun, Kug-Jin ; Kim, Kyu-Heon ; Hur, Nam-Ho ; Lee, Soo-In ; Park, Gwang-Hoon ;
ETRI Journal, volume 32, issue 6, 2010, Pages 961~964
DOI : 10.4218/etrij.10.0210.0138
This letter introduces a stereoscopic video broadcasting system that provides 3D visual service and has full backward compatibility with legacy digital television (DTV) service in the same channel capacity. The proposed stereoscopic video broadcasting system in this letter is composed of both a hybrid codec and a multiplexer with a newly defined stereoscopic-related signaling method. In conclusion, the proposed method can be effectively applied for 3D broadcasting services without major changes in legacy broadcasting platforms.
On the Distribution Functions of Ratios Involving Gaussian Random Variables
Park, Seung-Keun ;
ETRI Journal, volume 32, issue 6, 2010, Pages 965~968
DOI : 10.4218/etrij.10.0210.0201
In this letter, we derive the distribution functions of five ratios involving two correlated Gaussian random variables by using the rotation of Cartesian coordinates. The results can be used in evaluating the various probability performances of wireless communications systems.
Chip Impedance Evaluation Method for UHF RFID Transponder ICs over Absorbed Input Power
Yang, Jeen-Mo ; Yeo, Jun-Ho ;
ETRI Journal, volume 32, issue 6, 2010, Pages 969~971
DOI : 10.4218/etrij.10.0210.0208
Based on a de-embedding technique, a new method is proposed which is capable of evaluating chip impedance behavior over absorbed power in flip-chip bonded UHF radio frequency identification transponder ICs. For the de-embedding, four compact co-planar test fixtures, an equivalent circuit for the fixtures, and a parameter extraction procedure for the circuit are developed. The fixtures are designed such that the chip can absorb as much power as possible from a power source without radiating appreciable power. Experimental results show that the proposed modeling method is accurate and produces reliable chip impedance values related with absorbed power.
Lossy Source Compression of Non-Uniform Binary Source via Reinforced Belief Propagation over GQ-LDGM Codes
Zheng, Jianping ; Bai, Baoming ; Li, Ying ;
ETRI Journal, volume 32, issue 6, 2010, Pages 972~975
DOI : 10.4218/etrij.10.0210.0204
In this letter, we consider the lossy coding of a non-uniform binary source based on GF(q)-quantized low-density generator matrix (LDGM) codes with check degree
=2. By quantizing the GF(q) LDGM codeword, a non-uniform binary codeword can be obtained, which is suitable for direct quantization of the non-uniform binary source. Encoding is performed by reinforced belief propagation, a variant of belief propagation. Simulation results show that the performance of our method is quite close to the theoretic rate-distortion bounds. For example, when the GF(16)-LDGM code with a rate of 0.4 and block-length of 1,500 is used to compress the non-uniform binary source with probability of 1 being 0.23, the distortion is 0.091, which is very close to the optimal theoretical value of 0.074.