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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 37, Issue 6 - Dec 2015
Volume 37, Issue 5 - Oct 2015
Volume 37, Issue 4 - Aug 2015
Volume 37, Issue 3 - May 2015
Volume 37, Issue 2 - Apr 2015
Volume 37, Issue 1 - Feb 2015
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Blind Hopping Phase Estimator in Frequency-Hopped FM and BFSK Systems
Kim, Myungsup ; Seong, Jinsuk ; Lee, Seong-Ro ;
ETRI Journal, volume 37, issue 1, 2015, Pages 1~10
DOI : 10.4218/etrij.15.0114.0809
A blind hopping phase estimator is proposed for the demodulation of received signals in frequency-hopping spread spectrum systems. The received signals are assumed to be bandwidth limited with a shaping filter, modulated as frequency modulation (FM) or binary frequency shift keying (BFSK), and hopped by predetermined random frequency sequences. In the demodulation procedure in this paper, the hopping frequency tracking is accomplished by choosing a frequency component with maximum amplitude after taking a discrete Fourier transform, and the hopping phase estimator performs the conjugated product of two consecutive signals and moving-average filtering. The probability density function and Cramer-Rao low bound (CRLB) of the proposed estimator are evaluated. The proposed scheme not only is very simple to implement but also performs close to the CRLB in demodulating hopped FM/BFSK signals.
Optimal Power Allocation for Channel Estimation of OFDM Uplinks in Time-Varying Channels
Yao, Rugui ; Liu, Yinsheng ; Li, Geng ; Xu, Juan ;
ETRI Journal, volume 37, issue 1, 2015, Pages 11~20
DOI : 10.4218/etrij.15.0114.0758
This paper deals with optimal power allocation for channel estimation of orthogonal frequency-division multiplexing uplinks in time-varying channels. In the existing literature, the estimation of time-varying channel response in an uplink environment can be accomplished by estimating the corresponding channel parameters. Accordingly, the optimal power allocation studied in the literature has been in terms of minimizing the mean square error of the channel estimation. However, the final goal for channel estimation is to enable the application of coherent detection, which usually means high spectral efficiency. Therefore, it is more meaningful to optimize the power allocation in terms of capacity. In this paper, we investigate capacity with imperfect channel estimation. By exploiting the derived capacity expression, an optimal power allocation strategy is developed. With this developed power allocation strategy, improved performance can be observed, as demonstrated by the numerical results.
Compact Triple-Band Monopole Antenna for WLAN/WiMAX-Band USB Dongle Applications
Shi, Ya Wei ; Xiong, Ling ; Chen, Meng Gang ;
ETRI Journal, volume 37, issue 1, 2015, Pages 21~25
DOI : 10.4218/etrij.15.0114.0676
A miniaturized triple-band antenna suitable for wireless USB dongle applications is proposed and investigated in this paper. The presented antenna, simply consisting of a circular-arc-shaped stub, an L-shaped stub, a microstrip feed line, and a rectangular ground plane has a compact size of
and is capable of generating three separate resonant modes with very good impedance matching. The measurement results show that the antenna has several impedance bandwidths for S11
-10 dB of 260 MHz (2.24 GHz to 2.5 GHz), 320 MHz (3.4 GHz to 3.72 GHz), and 990 MHz (5.1 GHz to 6.09 GHz), which can be applied to both 2.4/5.2/5.8 GHz WLAN bands and 3.5/5.5 GHz WiMAX bands. Moreover, nearly-omni-directional radiation patterns and stable gain across the operating bands can be obtained.
Bandwidth Enhancement of Circularly Polarized Dielectric Resonator Antenna
Sun, Ru-Ying ;
ETRI Journal, volume 37, issue 1, 2015, Pages 26~31
DOI : 10.4218/etrij.15.0114.0637
Axial-ratio (AR) bandwidth enhancement is achieved for a circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) using a wideband hybrid coupler (WHC) combined with dual probe feed. The presented WHC, comprised of a Wilkinson power divider and a wideband
shifter, delivers good characteristics in terms of 3 dB power splitting and consistent
) phase shifting over a wide bandwidth. In turn, the proposed CP DRA, for the employment of the WHC, in place of conventional designs, provides a significant enhancement on AR bandwidth and impedance matching. The antenna prototype with the WHC exhibits a 3 dB AR bandwidth of 48.66%, an impedance bandwidth of 52.5% for voltage standing wave ratio (VSWR)
, and a bandwidth of 44.66% for a gain of no less than 3 dBi. Experiments demonstrate that the proposed WHC is suitable for broadband CP DRA design.
Low Complexity Discrete Hartley Transform Precoded OFDM System over Frequency-Selective Fading Channel
Ouyang, Xing ; Jin, Jiyu ; Jin, Guiyue ; Li, Peng ;
ETRI Journal, volume 37, issue 1, 2015, Pages 32~42
DOI : 10.4218/etrij.15.0114.0513
Orthogonal frequency-division multiplexing (OFDM) suffers from spectral nulls of frequency-selective fading channels. Linear precoded (LP-) OFDM is an effective method that guarantees symbol detectability by spreading the frequency-domain symbols over the whole spectrum. This paper proposes a computationally efficient and low-cost implementation for discrete Hartley transform (DHT) precoded OFDM systems. Compared to conventional DHT-OFDM systems, at the transmitter, both the DHT and the inverse discrete Fourier transform are replaced by a one-level butterfly structure that involves only one addition per symbol to generate the time-domain DHT-OFDM signal. At the receiver, only the DHT is required to recover the distorted signal with a single-tap equalizer in contrast to both the DHT and the DFT in the conventional DHT-OFDM. Theoretical analysis of DHT-OFDM with linear equalizers is presented and confirmed by numerical simulation. It is shown that the proposed DHT-OFDM system achieves similar performance when compared to other LP-OFDMs but exhibits a lower implementation complexity and peak-to-average power ratio.
Joint Compensation of Transmitter and Receiver IQ Imbalance in OFDM Systems Based on Selective Coefficient Updating
Rasi, Jafar ; Tazehkand, Behzad Mozaffari ; Niya, Javad Musevi ;
ETRI Journal, volume 37, issue 1, 2015, Pages 43~53
DOI : 10.4218/etrij.15.0114.0293
In this paper, a selective coefficient updating (SCU) approach at each branch of the per-tone equalization (PTEQ) structure has been applied for insufficient cyclic prefix (CP) length. Because of the high number of adaptive filters and their complex adaption process in the PTEQ structure, SCU has been proposed. Using this method leads to a reduction in the computational complexity, while the performance remains almost unchanged. Moreover, the use of set-membership filtering with variable step size is proposed for a sufficient CP case to increase convergence speed and decrease the average number of calculations. Simulation results show that despite the aforementioned algorithms having similar performance in comparison with conventional algorithms, they are able to reduce the number of calculations necessary. In addition, compensation of both the channel effect and the transmitter/receiver in-phase/quadrature-phase imbalances are achievable by these algorithms.
LDPC Decoding by Failed Check Nodes for Serial Concatenated Code
Yu, Seog Kun ; Joo, Eon Kyeong ;
ETRI Journal, volume 37, issue 1, 2015, Pages 54~60
DOI : 10.4218/etrij.15.0114.0107
The use of serial concatenated codes is an effective technique for alleviating the error floor phenomenon of low-density parity-check (LDPC) codes. An enhanced sum-product algorithm (SPA) for LDPC codes, which is suitable for serial concatenated codes, is proposed in this paper. The proposed algorithm minimizes the number of errors by using the failed check nodes (FCNs) in LDPC decoding. Hence, the error-correcting capability of the serial concatenated code can be improved. The number of FCNs is simply obtained by the syndrome test, which is performed during the SPA. Hence, the decoding procedure of the proposed algorithm is similar to that of the conventional algorithm. The error performance of the proposed algorithm is analyzed and compared with that of the conventional algorithm. As a result, a gain of 1.4 dB can be obtained by the proposed algorithm at a bit error rate of
. In addition, the error performance of the proposed algorithm with just 30 iterations is shown to be superior to that of the conventional algorithm with 100 iterations.
Novel Filtering Power Divider with External Isolation Resistors
Lu, Yun-Long ; Wang, Shun ; Dai, Gao-Le ; Li, Kai ;
ETRI Journal, volume 37, issue 1, 2015, Pages 61~65
DOI : 10.4218/etrij.15.0114.0058
In this paper, a novel filtering power divider with external isolation resistors is presented. The proposed power divider can be considered as an integration of a bandpass filter and a Gysel power divider. Based on the circuit topology, a high-order filtering power divider can be easily realized. Odd- and even-mode models are employed to analyze the filtering and power splitting functions. For demonstration, a third-order filtering power divider operating at 1.5 GHz is designed and implemented. The measured results exhibit an isolation between the output ports that is better than 20 dB at around the center frequency.
Bandwidth-Efficient Selective Retransmission for MIMO-OFDM Systems
Zia, Muhammad ; Kiani, Tamoor ; Saqib, Nazar A. ; Shah, Tariq ; Mahmood, Hasan ;
ETRI Journal, volume 37, issue 1, 2015, Pages 66~76
DOI : 10.4218/etrij.15.0114.0050
In this work, we propose an efficient selective retransmission method for multiple-input and multiple-output (MIMO) wireless systems under orthogonal frequency-division multiplexing (OFDM) signaling. A typical received OFDM frame may have some symbols in error, which results in a retransmission of the entire frame. Such a retransmission is often unnecessary, and to avoid this, we propose a method to selectively retransmit symbols that correspond to poor-quality subcarriers. We use the condition numbers of the subcarrier channel matrices of the MIMO-OFDM system as a quality measure. The proposed scheme is embedded in the modulation layer and is independent of conventional hybrid automatic repeat request (HARQ) methods. The receiver integrates the original OFDM and the punctured retransmitted OFDM signals for more reliable detection. The targeted retransmission results in fewer negative acknowledgements from conventional HARQ algorithms, which results in increasing bandwidth and power efficiency. We investigate the efficacy of the proposed method for optimal and suboptimal receivers. The simulation results demonstrate the efficacy of the proposed method on throughput for MIMO-OFDM systems.
Modeling and Stimulating Node Cooperation in Wireless Ad Hoc Networks
Arghavani, Abbas ; Arghavani, Mahdi ; Sargazi, Abolfazl ; Ahmadi, Mahmood ;
ETRI Journal, volume 37, issue 1, 2015, Pages 77~87
DOI : 10.4218/etrij.15.0113.1371
In wireless networks, cooperation is necessary for many protocols, such as routing, clock synchronization, and security. It is known that cooperator nodes suffer greatly from problems such as increasing energy consumption. Therefore, rational nodes have no incentive to cooperatively forward traffic for others. A rational node is different from a malicious node. It is a node that makes the best decision in each state (cooperate or non-cooperate). In this paper, game theory is used to analyze the cooperation between nodes. An evolutionary game has been investigated using two nodes, and their strategies have been compared to find the best one. Subsequently, two approaches, one based on a genetic algorithm (GA) and the other on learning automata (LA), are presented to incite nodes for cooperating in a noisy environment. As you will see later, the GA strategy is able to disable the effect of noise by using a big enough chromosome; however, it cannot persuade nodes to cooperate in a noisefree environment. Unlike the GA strategy, the LA strategy shows good results in a noise-free environment because it has good agreement in cooperation-based strategies in both types of environment (noise-free and noisy).
Development of Scent Display and Its Authoring Tool
Kim, Jeong Do ; Choi, Ji Hoon ; Lim, Seung Ju ; Park, Sung Dae ; Kim, Jung Ju ; Ahn, Chung Hyun ;
ETRI Journal, volume 37, issue 1, 2015, Pages 88~96
DOI : 10.4218/etrij.15.0113.0078
The purpose of this study is to design an authoring tool and a corresponding device for an olfactory display that can augment the immersion and reality in broadcasting services. The developed authoring tool allows an olfactory display to be properly synchronized with the existing video service by applying the standardized format using ISO/IEC 23005 (MPEG-V) and the corresponding developed scent display device. To propose the proper data format for the olfactory display, we have analyzed both the multimodal combination and the cross-modality related to the olfactory display. From the results of the analysis, we derived a set of olfactory parameters for the olfactory display that are related to emotion. The analyzed parameters related to emotion in an olfactory display are synchronization, scent intensity, scent persistence, and hedonic tone. These parameters should be controlled so that the olfactory display can be in harmony with the existing media to augment emotion. In addition, we developed a scent display device that can generate many kinds of scents and that satisfies design conditions for olfactory parameters that are for use with broadcasting services.
Design of SCR-Based ESD Protection Circuit for 3.3 V I/O and 20 V Power Clamp
Jung, Jin Woo ; Koo, Yong Seo ;
ETRI Journal, volume 37, issue 1, 2015, Pages 97~106
DOI : 10.4218/etrij.15.0114.0730
In this paper, MOS-triggered silicon-controlled rectifier (SCR)-based electrostatic discharge (ESD) protection circuits for mobile application in 3.3 V I/O and SCR-based ESD protection circuits with floating N+/P+ diffusion regions for inverter and light-emitting diode driver applications in 20 V power clamps were designed. The breakdown voltage is induced by a grounded-gate NMOS (ggNMOS) in the MOS-triggered SCR-based ESD protection circuit for 3.3 V I/O. This lowers the breakdown voltage of the SCR by providing a trigger current to the P-well of the SCR. However, the operation resistance is increased compared to SCR, because additional diffusion regions increase the overall resistance of the protection circuit. To overcome this problem, the number of ggNMOS fingers was increased. The ESD protection circuit for the power clamp application at 20 V had a breakdown voltage of 23 V; the product of a high holding voltage by the N+/P+ floating diffusion region. The trigger voltage was improved by the partial insertion of a P-body to narrow the gap between the trigger and holding voltages. The ESD protection circuits for low- and high-voltage applications were designed using
Bipolar-CMOS-DMOS technology, with
width. Electrical characteristics and robustness are analyzed by a transmission line pulse measurement and an ESD pulse generator (ESS-6008).
Flexible Prime-Field Genus 2 Hyperelliptic Curve Cryptography Processor with Low Power Consumption and Uniform Power Draw
Ahmadi, Hamid-Reza ; Afzali-Kusha, Ali ; Pedram, Massoud ; Mosaffa, Mahdi ;
ETRI Journal, volume 37, issue 1, 2015, Pages 107~117
DOI : 10.4218/etrij.15.0114.0418
This paper presents an energy-efficient (low power) prime-field hyperelliptic curve cryptography (HECC) processor with uniform power draw. The HECC processor performs divisor scalar multiplication on the Jacobian of genus 2 hyperelliptic curves defined over prime fields for arbitrary field and curve parameters. It supports the most frequent case of divisor doubling and addition. The optimized implementation, which is synthesized in a
standard CMOS technology, performs an 81-bit divisor multiplication in 503 ms consuming only
of energy (average power consumption is
). In addition, we present a technique to make the power consumption of the HECC processor more uniform and lower the peaks of its power consumption.
New Thermal-Aware Voltage Island Formation for 3D Many-Core Processors
Hong, Hyejeong ; Lim, Jaeil ; Lim, Hyunyul ; Kang, Sungho ;
ETRI Journal, volume 37, issue 1, 2015, Pages 118~127
DOI : 10.4218/etrij.15.0114.0257
The power consumption of 3D many-core processors can be reduced, and the power delivery of such processors can be improved by introducing voltage island (VI) design using on-chip voltage regulators. With the dramatic growth in the number of cores that are integrated in a processor, however, it is infeasible to adopt per-core VI design. We propose a 3D many-core processor architecture that consists of multiple voltage clusters, where each has a set of cores that share an on-chip voltage regulator. Based on the architecture, the steady state temperature is analyzed so that the thermal characteristic of each voltage cluster is known. In the voltage scaling and task scheduling stages, the thermal characteristics and communication between cores is considered. The consideration of the thermal characteristics enables the proposed VI formation to reduce the total energy consumption, peak temperature, and temperature gradients in 3D many-core processors.
Basic RF Characteristics of Fishbone-Type Transmission Line Employing Comb-Type Ground Plane (FTLCGP) on PES Substrate for Use in Flexible Passive Circuits
Yun, Young ; Jeong, Jang-Hyeon ; Kim, Hong Seung ; Jang, Nakwon ;
ETRI Journal, volume 37, issue 1, 2015, Pages 128~137
DOI : 10.4218/etrij.15.0114.0244
In this work, a fishbone-type transmission line employing a comb-type ground plane (FTLCGP) was fabricated on polyethersulfone (PES) substrate, and its RF characteristics were thoroughly investigated. According to the results, it was found that the FTLCGP on PES showed periodic capacitance values much higher than other types of transmission lines due to a coupling capacitance between the signal line and ground, which resulted in a reduction of wavelength and line width. Using the theoretical analysis, we also extracted the bandwidth characteristic of the FTLCGP on PES. According to the result, the FTLCGP structure showed a cut-off frequency of 280 GHz.
Non-constraining Online Signature Reconstruction System for Persons with Handwriting Problems
Abbadi, Belkacem ; Mostefai, Messaoud ; Oulefki, Adel ;
ETRI Journal, volume 37, issue 1, 2015, Pages 138~146
DOI : 10.4218/etrij.15.0114.0253
This paper presents a new non-constraining online optical handwritten signature reconstruction system that, in the main, makes use of a transparent glass pad placed in front of a color camera. The reconstruction approach allows efficient exploitation of hand activity during a signing process; thus, the system as a whole can be seen as a viable alternative to other similar acquisition tools. This proposed system allows people with physical or emotional problems to carry out their own signatures without having to use a pen or sophisticated acquisition system. Moreover, the developed reconstruction signature algorithms have low computational complexity and are therefore well suited for a hardware implementation on a dedicated smart system.
CAWR: Buffer Replacement with Channel-Aware Write Reordering Mechanism for SSDs
Wang, Ronghui ; Chen, Zhiguang ; Xiao, Nong ; Zhang, Minxuan ; Dong, Weihua ;
ETRI Journal, volume 37, issue 1, 2015, Pages 147~156
DOI : 10.4218/etrij.15.0114.0055
A typical solid-state drive contains several independent channels that can be operated in parallel. To exploit this channel-level parallelism, a variety of works proposed to split consecutive write sequences into small segments and schedule them to different channels. This scheme exploits the parallelism but breaks the spatial locality of write traffic; thus, it is able to significantly degrade the efficiency of garbage collection. This paper proposes a channel-aware write reordering (CAWR) mechanism to schedule write requests to different channels more intelligently. The novel mechanism encapsulates correlated pages into a cluster beforehand. All pages belonging to a cluster are scheduled to the same channels to exploit spatial locality, while different clusters are scheduled to different channels to exploit the parallelism. As CAWR covers both garbage collection and I/O performance, it outperforms existing schemes significantly. Trace-driven simulation results demonstrate that the CAWR mechanism reduces the average response time by 26% on average and decreases the valid page copies by 10% on average, while achieving a similar hit ratio to that of existing mechanisms.
A Novel GPU Power Model for Accurate Smartphone Power Breakdown
Kim, Young Geun ; Kim, Minyong ; Kim, Jae Min ; Sung, Minyoung ; Chung, Sung Woo ;
ETRI Journal, volume 37, issue 1, 2015, Pages 157~164
DOI : 10.4218/etrij.15.0113.1411
As GPU power consumption in smartphones increases with more advanced graphic performance, it becomes essential to estimate GPU power consumption accurately. The conventional GPU power model assumes, simply, that a GPU consumes constant power when turned on; however, this is no longer true for recent smartphone GPUs. In this paper, we propose an accurate GPU power model for smartphones, considering newly adopted dynamic voltage and frequency scaling. For the proposed GPU power model, our evaluation results show that the error rate for system power estimation is as low as 2.9%, on average, and 4.6% in the worst case.
Novel Technique in Linear Cryptanalysis
Sun, Wen-Long ; Guan, Jie ;
ETRI Journal, volume 37, issue 1, 2015, Pages 165~174
DOI : 10.4218/etrij.15.0113.1237
In this paper, we focus on a novel technique called the cube-linear attack, which is formed by combining cube attacks with linear attacks. It is designed to recover the secret information in a probabilistic polynomial and can reduce the data complexity required for a successful attack in specific circumstances. In addition to the different combination strategies of the two attacks, two cube-linear schemes are discussed. Applying our method of a cube-linear attack to a reduced-round Trivium, as an example, we get better linear cryptanalysis results. More importantly, we believe that the improved linear cryptanalysis technique introduced in this paper can be extended to other ciphers.
System of Systems Approach to Formal Modeling of CPS for Simulation-Based Analysis
Lee, Kyou Ho ; Hong, Jeong Hee ; Kim, Tag Gon ;
ETRI Journal, volume 37, issue 1, 2015, Pages 175~185
DOI : 10.4218/etrij.15.0114.0863
This paper presents a system-of-systems (SoS) approach to the formal modeling of a cyber-physical system (CPS) for simulation-based analysis. The approach is based on a convergence technology for modeling and simulation of a highly complex system in which SoS modeling methodology, hybrid systems modeling theory, and simulation interoperation technology are merged. The methodology maps each constituent system of a CPS to a disparate model of either continuous or discrete types. The theory employs two formalisms for modeling of the two model types with formal specification of interfaces between them. Finally, the technology adapts a simulation bus called DEVS BUS whose protocol synchronizes time and exchange messages between subsystems simulation. Benefits of the approach include reusability of simulation models and environments, and simulation-based analysis of subsystems of a CPS in an inter-relational manner.
Novel Trusted Hierarchy Construction for RFID Sensor-Based MANETs Using ECCs
Kumar, Adarsh ; Gopal, Krishna ; Aggarwal, Alok ;
ETRI Journal, volume 37, issue 1, 2015, Pages 186~196
DOI : 10.4218/etrij.15.0114.0177
In resource-constrained, low-cost, radio-frequency identification (RFID) sensor-based mobile ad hoc networks (MANETs), ensuring security without performance degradation is a major challenge. This paper introduces a novel combination of steps in lightweight protocol integration to provide a secure network for RFID sensor-based MANETs using error-correcting codes (ECCs). The proposed scheme chooses a quasi-cyclic ECC. Key pairs are generated using the ECC for establishing a secure message communication. Probability analysis shows that code-based identification; key generation; and authentication and trust management schemes protect the network from Sybil, eclipse, and de-synchronization attacks. A lightweight model for the proposed sequence of steps is designed and analyzed using an Alloy analyzer. Results show that selection processes with ten nodes and five subgroup controllers identify attacks in only a few milliseconds. Margrave policy analysis shows that there is no conflict among the roles of network members.
Bargaining-Based Smart Grid Pricing Model for Demand Side Management Scheduling
Park, Youngjae ; Kim, Sungwook ;
ETRI Journal, volume 37, issue 1, 2015, Pages 197~202
DOI : 10.4218/etrij.15.0114.0007
A smart grid is a modernized electrical grid that uses information about the behaviors of suppliers and consumers in an automated fashion to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity. In the operation of a smart grid, demand side management (DSM) plays an important role in allowing customers to make informed decisions regarding their energy consumption. In addition, it helps energy providers reduce peak load demand and reshapes the load profile. In this paper, we propose a new DSM scheduling scheme that makes use of the day-ahead pricing strategy. Based on the Rubinstein-Stahl bargaining model, our pricing strategy allows consumers to make informed decisions regarding their power consumption, while reducing the peak-to-average ratio. With a simulation study, it is demonstrated that the proposed scheme can increase the sustainability of a smart grid and reduce overall operational costs.