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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 31, Issue 6 - Dec 2009
Volume 31, Issue 5 - Oct 2009
Volume 31, Issue 4 - Aug 2009
Volume 31, Issue 3 - Jun 2009
Volume 31, Issue 2 - Apr 2009
Volume 31, Issue 1 - Feb 2009
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Curved Projection Integral Imaging Using an Additional Large-Aperture Convex Lens for Viewing Angle Improvement
Hyun, Joo-Bong ; Hwang, Dong-Choon ; Shin, Dong-Hak ; Lee, Byung-Gook ; Kim, Eun-Soo ;
ETRI Journal, volume 31, issue 2, 2009, Pages 105~110
In this paper, we propose a curved projection integral imaging system to improve the horizontal and vertical viewing angles. The proposed system can be easily implemented by additional use of a large-aperture convex lens in conventional projection integral imaging. To obtain the simultaneous display of 3D images through real and virtual image fields, we propose a computer-generated pickup method based on ray optics and elemental images, which are synthesized for the proposed system. To show the feasibility of the proposed system, preliminary experiments are carried out. Experimental results indicate that our system improves the viewing angle and displays 3D images simultaneously in real and virtual image fields.
Mapping and Scheduling for Circuit-Switched Network-on-Chip Architecture
Wu, Chia-Ming ; Chi, Hsin-Chou ; Chang, Ruay-Shiung ;
ETRI Journal, volume 31, issue 2, 2009, Pages 111~120
Network-on-chip (NoC) architecture provides a highper-formance communication infrastructure for system-on-chip designs. Circuit-switched networks guarantee transmission latency and throughput; hence, they are suitable for NoC architecture with real-time traffic. In this paper, we propose an efficient integrated scheme which automatically maps application tasks onto NoC tiles, establishes communication circuits, and allocates a proper bandwidth for each circuit. Simulation results show that the average waiting times of packets in a switch in
mesh NoC networks are 0.59, 0.62, and 0.61, respectively. The latency of circuits is significantly decreased. Furthermore, the buffer of a switch in NoC only needs to accommodate the data of one time slot. The cost of the switch in the circuit-switched network can be reduced using our scheme. Our design provides an effective solution for a critical step in NoC design.
Fast Training of Structured SVM Using Fixed-Threshold Sequential Minimal Optimization
Lee, Chang-Ki ; Jang, Myung-Gil ;
ETRI Journal, volume 31, issue 2, 2009, Pages 121~128
In this paper, we describe a fixed-threshold sequential minimal optimization (FSMO) for structured SVM problems. FSMO is conceptually simple, easy to implement, and faster than the standard support vector machine (SVM) training algorithms for structured SVM problems. Because FSMO uses the fact that the formulation of structured SVM has no bias (that is, the threshold b is fixed at zero), FSMO breaks down the quadratic programming (QP) problems of structured SVM into a series of smallest QP problems, each involving only one variable. By involving only one variable, FSMO is advantageous in that each QP sub-problem does not need subset selection. For the various test sets, FSMO is as accurate as an existing structured SVM implementation (SVM-Struct) but is much faster on large data sets. The training time of FSMO empirically scales between O(n) and O(
), while SVM-Struct scales between O(
) and O(
Efficient Computation of Eta Pairing over Binary Field with Vandermonde Matrix
Shirase, Masaaki ; Takagi, Tsuyoshi ; Choi, Doo-Ho ; Han, Dong-Guk ; Kim, Ho-Won ;
ETRI Journal, volume 31, issue 2, 2009, Pages 129~139
This paper provides an efficient algorithm for computing the
pairing on supersingular elliptic curves over fields of characteristic two. In the proposed algorithm, we deploy a modified multiplication in
using the Vandermonde matrix. For F, G
the proposed multiplication method computes
is eliminated by the final exponentiation of the
pairing computation. The proposed multiplication method asymptotically requires only 7 multiplications in
, while the cost of the previously fastest Karatsuba method is 9 multiplications in
. Consequently, the cost of the
pairing computation is reduced by 14.3%.
Statistical Investigation on Class Mutation Operators
Ma, Yu-Seung ; Kwon, Yong-Rae ; Kim, Sang-Woon ;
ETRI Journal, volume 31, issue 2, 2009, Pages 140~150
Although mutation testing is potentially powerful, it is a computationally expensive testing method. To investigate how we can reduce the cost of object-oriented mutation testing, we have conducted empirical studies on class mutation operators. We applied class mutation operators to 866 classes contained in six open-source programs. An analysis of the number and the distribution of class mutants generated and preliminary data on the effectiveness of some operators are provided. Our study shows that the overall number of class mutants is smaller than for traditional mutants, which offers the possibility that class mutation can be made practically affordable.
Adaptive Multiview Video Coding Scheme Based on Spatiotemporal Correlation Analyses
Zhang, Yun ; Jiang, Gang-Yi ; Yu, Mei ; Ho, Yo-Sung ;
ETRI Journal, volume 31, issue 2, 2009, Pages 151~161
In this paper, we propose an adaptive multiview video coding scheme based on spatiotemporal correlation analyses using hierarchical B picture (AMVC-HBP) for the integrative encoding performances, including high compression efficiency, low complexity, fast random access, and view scalability, by integrating multiple prediction structures. We also propose an in-coding mode-switching algorithm that enables AMVC-HBP to adaptively select a better prediction structure in the encoding process without any additional complexity. Experimental results show that AMVC-HBP outperforms the previous multiview video coding scheme based on H.264/MPEG-4 AVC using the hierarchical B picture (MVC-HBP) on low complexity for 21.5%, on fast random access for about 20%, and on view scalability for 11% to 15% on average. In addition, distinct coding gain can be achieved by AMVC-HBP for dense and fast-moving sequences compared with MVC-HBP.
Blind MMSE Equalization of FIR/IIR Channels Using Oversampling and Multichannel Linear Prediction
Chen, Fangjiong ; Kwong, Sam ; Kok, Chi-Wah ;
ETRI Journal, volume 31, issue 2, 2009, Pages 162~172
A linear-prediction-based blind equalization algorithm for single-input single-output (SISO) finite impulse response/infinite impulse response (FIR/IIR) channels is proposed. The new algorithm is based on second-order statistics, and it does not require channel order estimation. By oversampling the channel output, the SISO channel model is converted to a special single-input multiple-output (SIMO) model. Two forward linear predictors with consecutive prediction delays are applied to the subchannel outputs of the SIMO model. It is demonstrated that the partial parameters of the SIMO model can be estimated from the difference between the prediction errors when the length of the predictors is sufficiently large. The sufficient filter length for achieving the optimal prediction is also derived. Based on the estimated parameters, both batch and adaptive minimum-mean-square-error equalizers are developed. The performance of the proposed equalizers is evaluated by computer simulations and compared with existing algorithms.
Estimation-Based Load-Balancing with Admission Control for Cluster Web Servers
Sharifian, Saeed ; Motamedi, Seyed Ahmad ; Akbari, Mohammad Kazem ;
ETRI Journal, volume 31, issue 2, 2009, Pages 173~181
The growth of the World Wide Web and web-based applications is creating demand for high performance web servers to offer better throughput and shorter user-perceived latency. This demand leads to widely used cluster-based web servers in the Internet infrastructure. Load balancing algorithms play an important role in boosting the performance of cluster web servers. Previous load balancing algorithms suffer a significant performance drop under dynamic and database-driven workloads. We propose an estimation-based load balancing algorithm with admission control for cluster-based web servers. Because it is difficult to accurately determine the load of web servers, we propose an approximate policy. The algorithm classifies requests based on their service times and tracks the number of outstanding requests from each class in each web server node to dynamically estimate each web server load state. The available capacity of each web server is then computed and used for the load balancing and admission control decisions. The implementation results confirm that the proposed scheme improves both the mean response time and the throughput of clusters compared to rival load balancing algorithms and prevents clusters being overloaded even when request rates are beyond the cluster capacity.
Application of ANFIS Power Control for Downlink CDMA-Based LMDS Systems
Lee, Ze-Shin ; Tsay, Mu-King ; Liao, Chien-Hsing ;
ETRI Journal, volume 31, issue 2, 2009, Pages 182~192
Rain attenuation and intercell interference are two crucial factors in the performance of broadband wireless access networks such as local multipoint distribution systems (LMDS) operating at frequencies above 20 GHz. Power control can enhance the performance of downlink CDMA-based LMDS systems by reducing intercell interference under clear sky conditions; however, it may damage system performance under rainy conditions. To ensure robust operation under both clear sky and rainy conditions, we propose a novel power-control scheme which applies an adaptive neuro-fuzzy inference system (ANFIS) for downlink CDMA-based LMDS systems. In the proposed system, the rain rate and the number of users are two inputs of the fuzzy inference system, and output is defined as channel quality, which is applied in the power control scheme to adjust the power control region. Moreover, ITU-R P.530 is employed to estimate the rain attenuation. The influence of the rain rate and the number of users on the distance-based power control (DBPC) scheme is included in the simulation model as the training database. Simulation results indicate that the proposed scheme improves the throughput of the DBPC scheme.
Blind Adaptive Multiuser Detection for the MC-CDMA Systems Using Orthogonalized Subspace Tracking
Ali, Imran ; Kim, Doug-Nyun ; Lim, Jong-Soo ;
ETRI Journal, volume 31, issue 2, 2009, Pages 193~200
In this paper, we study the performance of subspace-based multiuser detection techniques for multicarrier code-division multiple access (MC-CDMA) systems. We propose an improvement in the PASTd algorithm by cascading it with the classical Gram-Schmidt procedure to orthonormalize the eigenvectors after their sequential extraction. The tracking of signal subspace using this algorithm, which we call OPASTd, has a faster convergence as the eigenvectors are orthonormalized at each discrete time sample. This improved PASTd algorithm is then used to implement the subspace blind adaptive multiuser detection for MC-CDMA. We also show that, for multiuser detection, the complexity of the proposed scheme is lower than that of many other orthogonalization schemes found in the literature. Extensive simulation results are presented and discussed to demonstrate the performance of the proposed scheme.
Bandwidth Enhancement for SSN Suppression Using a Spiral-Shaped Power Island and a Modified EBG Structure for a
/4 Open Stub
Kim, Bo-Bae ; Kim, Dong-Wook ;
ETRI Journal, volume 31, issue 2, 2009, Pages 201~208
This paper proposes a spiral-shaped power island structure that can effectively suppress simultaneous switching noise (SSN) when the power plane drives high-speed integrated circuits in a small area. In addition, a new technique is presented which greatly improves the resonance peaks in a stopband by utilizing
/4 open stubs on a conventional periodic electromagnetic bandgap (EBG) power plane. Both proposed structures are simulated numerically and experimentally verified using commercially available 3D electromagnetic field simulation software. The results demonstrate that they achieve better SSN suppression performance than conventional periodic EBG structures.
Test-Generation-Based Fault Detection in Analog VLSI Circuits Using Neural Networks
Kalpana, Palanisamy ; Gunavathi, Kandasamy ;
ETRI Journal, volume 31, issue 2, 2009, Pages 209~214
In this paper, we propose a novel test methodology for the detection of catastrophic and parametric faults present in analog very large scale integration circuits. An automatic test pattern generation algorithm is proposed to generate piece-wise linear (PWL) stimulus using wavelets and a genetic algorithm. The PWL stimulus generated by the test algorithm is used as a test stimulus to the circuit under test. Faults are injected to the circuit under test and the wavelet coefficients obtained from the output response of the circuit. These coefficients are used to train the neural network for fault detection. The proposed method is validated with two IEEE benchmark circuits, namely, an operational amplifier and a state variable filter. This method gives 100% fault coverage for both catastrophic and parametric faults in these circuits.
How a Convergence Product Affects Related Markets: The Case of the Mobile Phone
Lee, Mi-Suk ; Lee, Jong-Su ; Cho, Young-Sang ;
ETRI Journal, volume 31, issue 2, 2009, Pages 215~224
Analyzing the diffusion of a convergence product is a new and challenging research field. It is very difficult to find research dealing with this issue due to the inherent complexity and lack of data. In analyzing the diffusion of a convergence product, we should simultaneously take into account its relationship with related single-function products because of their similarities in terms of technology and functionality. In this study, we empirically analyze the diffusion of the convergence mobile phones in South Korea and find that the convergence products can affect the diffusion of MP3 players and digital cameras positively or negatively. This research may be significant for business strategies in technology management and product development.
Novel Planar Metamaterial with a Negative Refractive Index
Kim, Dong-Ho ; Choi, Jae-Ick ;
ETRI Journal, volume 31, issue 2, 2009, Pages 225~227
A new planar metamaterial (MTM) with simultaneous negative values of permittivity (
) and permeability (
) is proposed. Our MTM is composed of two identical copper patterns etched on both sides of dielectric laminate, which is very thin and easy to fabricate. Unlike conventional MTMs, the proposed structure shows a negative refractive index (NRI) behavior with respect to a normally incident wave. To explain the underlying principle of the NRI characteristics, an equivalent resonant circuit model based on surface current density distribution is investigated. An eigenmode analysis and a three-dimensional wave simulation for the stacked MTM prism are also performed to verify the existence of negative refraction. The experimental results from the transmission and reflection measurement ensure the validity of our design approach and show good agreement with the theoretically predicted effective medium parameters.
InP-Based Polarization-Insensitive Planar Waveguide Concave Grating Demultiplexer with Flattened Spectral Response
Kwon, Oh-Kee ; Lee, Chul-Wook ; Lee, Dong-Hun ; Sim, Eun-Deok ; Kim, Jong-Hoi ; Baek, Yong-Soon ;
ETRI Journal, volume 31, issue 2, 2009, Pages 228~230
InP-based planar waveguide 48-channel concave grating demultiplexers with a channel spacing of 0.8 nm (100 GHz) are described and demonstrated. Polarization insensitivity and flattened spectral response are successfully achieved by the introduction of a polarization compensator and a two-focus grating, respectively. The fabricated device shows a polarization-dependent wavelength shift of less than 20 pm and a -3 dB spectral width of about 0.55 nm (68.75 GHz) over all channels.
Channel Enlargement of PON System Using Nonreciprocal Multiplexing Filter Based on CWDM
Kim, Bong-Kyu ; Yoon, Bin-Young ; Kwon, Yool ;
ETRI Journal, volume 31, issue 2, 2009, Pages 231~233
We propose a nonreciprocal filter based on coarse wavelength division multiplexing (CWDM) that reduces the upstream channel insertion loss in a passive optical network (PON). We also propose a method to increase the number of channels/optical network units (ONUs) in PON systems using the proposed filter to reduce the service cost per subscriber. Experimental results show that the PON system with the proposed 4-channel filter can reduce the power budget of the upstream and increase the number of ONUs by 3 to 4 times that of a conventional time-division multiplexing PON.
Switched-Capacitor Variable Gain Amplifier with Operational Amplifier Preset Technique
Cho, Young-Kyun ; Jeon, Young-Deuk ; Kwon, Jong-Kee ;
ETRI Journal, volume 31, issue 2, 2009, Pages 234~236
We present a novel operational amplifier preset technique for a switched-capacitor circuit to reduce the acquisition time by improving the slewing. The acquisition time of a variable gain amplifier (VGA) using the proposed technique is reduced by 30% compared with a conventional one; therefore, the power consumption of the VGA is decreased. For additional power reduction, a programmable capacitor array scheme is used in the VGA. In the 0.13
CMOS process, the VGA, which consists of three-stages, occupies 0.33
and dissipates 19.2 mW at 60 MHz with a supply voltage of 1.2 V. The gain range is 36.03 dB, which is controlled by a 10-bit control word with a gain error of
Development of 7-Year-Old Korean Child Model for Computational Dosimetry
Lee, Ae-Kyoung ; Byun, Jin-Kyu ; Park, Jin-Seo ; Choi, Hyung-Do ; Yun, Jae-Hoon ;
ETRI Journal, volume 31, issue 2, 2009, Pages 237~239
A whole-body voxel model of a 7-year-old male volunteer was developed from 384 axial magnetic resonance images (MRIs). The MRIs were acquired with intervals of 3 mm for the entire body in a body coil. In order to reduce the MRI acquisition time for the child, the repetition and echo times under T1 weighted image were chosen to be 566 ms and 8 ms, respectively. The MRIs were classified according to 30 types of tissues with known electrical parameters. The developed voxel model was adjusted to the physical average of 7-year-old Korean boys. The body weight of the adjusted model, calculated with the mass tissue densities, is within a 6% difference from the 50th percentile weight.
Fast Implementation of the Progressive Edge-Growth Algorithm
Chen, Lin ; Feng, Da-Zheng ;
ETRI Journal, volume 31, issue 2, 2009, Pages 240~242
A computationally efficient implementation of the progressive edge-growth algorithm is presented. This implementation uses an array of red-black (RB) trees to manage the layered structure of check nodes and adopts a new strategy to expand the Tanner graph. The complexity analysis and the simulation results show that the proposed approach reduces the computational effort effectively. In constructing a low-density parity check code with a length of
, the RB-tree-array-based implementation takes no more 10% of the time required by the original method.
Ultra-Low-Power Differential ISFET/REFET Readout Circuit
Thanachayanont, Apinunt ; Sirimasakul, Silar ;
ETRI Journal, volume 31, issue 2, 2009, Pages 243~245
A novel ultra-low-power readout circuit for a pH-sensitive ion-sensitive field-effect transistor (ISFET) is proposed. It uses an ISFET/reference FET (REFET) differential pair operating in weak-inversion and a simple current-mode metal-oxide semiconductor FET (MOSFET) translinear circuit. Simulation results verify that the circuit operates with excellent common-mode rejection ability and good linearity for a single pH range from 4 to 10, while only 4 nA is drawn from a single 1 V supply voltage.