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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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An Efficient Soft-Output MIMO Detection Method Based on a Multiple-Channel-Ordering Technique
Im, Tae-Ho ; Park, In-Soo ; Yoo, Hyun-Jong ; Yu, Sung-Wook ; Cho, Yong-Soo ;
ETRI Journal, volume 33, issue 5, 2011, Pages 661~669
DOI : 10.4218/etrij.11.0110.0574
In this paper, we propose an efficient soft-output signal detection method for spatially multiplexed multiple-input multiple-output (MIMO) systems. The proposed method is based on the ordered successive interference cancellation (OSIC) algorithm, but it significantly improves the performance of the original OSIC algorithm by solving the error propagation problem. The proposed method combines this enhanced OSIC algorithm with a multiple-channel-ordering technique in a very efficient way. As a result, the log likelihood ratio values can be computed by using a very small set of candidate symbol vectors. The proposed method has been synthesized with a 0.13-
CMOS technology for a
16-QAM MIMO system. The simulation and implementation results show that the proposed detector provides a very good solution in terms of performance and hardware complexity.
VSB-Based Digital On-Channel Repeater with Interference Cancellation System
Lee, Jae-Kwon ; Suh, Young-Woo ; Choi, Jin-Yong ; Seo, Jong-Soo ;
ETRI Journal, volume 33, issue 5, 2011, Pages 670~678
DOI : 10.4218/etrij.11.0110.0539
This paper investigates the design and performance of a digital on-channel repeater (DOCR) for use in Advanced Television Systems Committee (ATSC) digital television (DTV) broadcasting. The main drawback of a DOCR is the echo interference caused by coupling between transmitter and receiver antennas, which induces system instability and performance degradation. In order to overcome this problem, an echo canceller based on the adaptive echo channel estimation (ECE) technique has been researched and applied for a DOCR. However, in the case of ATSC, the pilot signal, which is used for carrier synchronization, may cause a DC offset error and reduce the isolation performance of the echo canceller for a DOCR in an ATSC network. Moreover, since the multipath fading effect of a radio channel usually occurs in a real environment, it should be minimized to improve the overall performance of a DOCR. Therefore, due to the limited isolation performance of echo canceller and the multipath fading effect, an interference cancellation system (ICS) is proposed for a DOCR in an ATSC network. The performance of the proposed DOCR with an ICS is evaluated by software simulation and hardware test results.
A Discrete-Amplitude Pulse Width Modulation for a High-Efficiency Linear Power Amplifier
Jeon, Young-Sang ; Nam, Sang-Wook ;
ETRI Journal, volume 33, issue 5, 2011, Pages 679~688
DOI : 10.4218/etrij.11.0110.0560
A new discrete-amplitude pulse width modulation (DAPWM) scheme for a high-efficiency linear power amplifier is proposed. A radio frequency (RF) input signal is divided into an envelope and a phase modulated carrier. The low-frequency envelope is modulated so that it can be represented by a pulse whose area is proportional to its amplitude. The modulated pulse has at least two different pulse amplitude levels in order that the duty ratios of the pulse are kept large for small input. Then, an RF pulse train is generated by mixing the modulated envelope with the phase modulated carrier. The RF pulse train is amplified by a switching-mode power amplifier, and the original RF input signal is restored by a band pass filter. Because duty ratios of the RF pulse train are kept large in spite of a small input envelope, the DAPWM technique can reduce loss from harmonic components. Furthermore, it reduces filtering efforts required to suppress harmonic components. Simulations show that the overall efficiency of the pulsed power amplifier with DAPWM is about 60.3% for a mobile WiMax signal. This is approximately a 73% increase compared to a pulsed power amplifier with PWM.
Performance of Two-User Two-Way Amplify-and-Forward Relaying Systems with Scheduling
Fang, Zhaoxi ; Li, Guosheng ; Li, Jun ;
ETRI Journal, volume 33, issue 5, 2011, Pages 689~694
DOI : 10.4218/etrij.11.0110.0622
In this paper, we study scheduling schemes for two-user two-way wireless relaying systems. Two transmission modes are considered: point-to-point direct transmission and two-way amplify-and-forward relaying. An optimal scheduling scheme that opportunistically selects the best transmission mode for each user is proposed to minimize the sum bit error rate (BER). The performance lower bound of the optimal scheduling scheme is analyzed, and closed-form expression of the lower-bound BER is derived. However, for optimal scheduling, the scheduler requires the knowledge of channel state information (CSI) of all links. To reduce the feedback information of CSI, we also propose a suboptimal scheduling scheme that selects the transmission mode using only the CSI of two direct links. Simulation results show that there are 4 dB to 8 dB gains for the proposed optimal and suboptimal schemes over the fixed direct transmission and fixed two-way relayed transmission scheme. The performance gap between the optimal and suboptimal scheduling schemes is small, which implies a good trade-off between implementation complexity and system performance.
An Improved Non-CSD 2-Bit Recursive Common Subexpression Elimination Method to Implement FIR Filter
Kamal, Hassan ; Lee, Joo-Hyun ; Koo, Bon-Tae ;
ETRI Journal, volume 33, issue 5, 2011, Pages 695~703
DOI : 10.4218/etrij.11.0110.0642
The number of adders and critical paths in a multiplier block of a multiple constant multiplication based implementation of a finite impulse response (FIR) filter can be minimized through common subexpression elimination (CSE) techniques. A two-bit common subexpression (CS) can be located recursively in a noncanonic sign digit (CSD) representation of the filter coefficients. An efficient algorithm is presented in this paper to improve the elimination of a CS from the multiplier block of an FIR filter so that it can be realized with fewer adders and low logical depth as compared to the existing CSE methods in the literature. Vinod and others claimed the highest reduction in the number of logical operators (LOs) without increasing the logic depth (LD) requirement. Using the design examples given by Vinod and others, we compare the average reduction in LOs and LDs achieved by our algorithm. Our algorithm shows average LO improvements of 30.8%, 5.5%, and 22.5% with a comparative LD requirement over that of Vinod and others for three design examples. Improvement increases as the filter order increases, and for the highest filter order and lowest coefficient width, the LO improvements are 70.3%, 75.3%, and 72.2% for the three design examples.
Hybrid Distributed Stochastic Addressing Scheme for ZigBee/IEEE 802.15.4 Wireless Sensor Networks
Kim, Hyung-Seok ; Yoon, Ji-Won ;
ETRI Journal, volume 33, issue 5, 2011, Pages 704~711
DOI : 10.4218/etrij.11.0110.0501
This paper proposes hybrid distributed stochastic addressing (HDSA), which combines the advantages of distributed addressing and stochastic addressing, to solve the problems encountered when constructing a network in a ZigBee-based wireless sensor network. HDSA can assign all the addresses for ZigBee beyond the limit of addresses assigned by the existing distributed address assignment mechanism. Thus, it can make the network scalable and can also utilize the advantages of tree routing. The simulation results reveal that HDSA has better addressing performance than distributed addressing and better routing performance than other on-demand routing methods.
A Prior Model of Structural SVMs for Domain Adaptation
Lee, Chang-Ki ; Jang, Myung-Gil ;
ETRI Journal, volume 33, issue 5, 2011, Pages 712~719
DOI : 10.4218/etrij.11.0110.0571
In this paper, we study the problem of domain adaptation for structural support vector machines (SVMs). We consider a number of domain adaptation approaches for structural SVMs and evaluate them on named entity recognition, part-of-speech tagging, and sentiment classification problems. Finally, we show that a prior model for structural SVMs outperforms other domain adaptation approaches in most cases. Moreover, the training time for this prior model is reduced compared to other domain adaptation methods with improvements in performance.
FEROM: Feature Extraction and Refinement for Opinion Mining
Jeong, Ha-Na ; Shin, Dong-Wook ; Choi, Joong-Min ;
ETRI Journal, volume 33, issue 5, 2011, Pages 720~730
DOI : 10.4218/etrij.11.0110.0627
Opinion mining involves the analysis of customer opinions using product reviews and provides meaningful information including the polarity of the opinions. In opinion mining, feature extraction is important since the customers do not normally express their product opinions holistically but separately according to its individual features. However, previous research on feature-based opinion mining has not had good results due to drawbacks, such as selecting a feature considering only syntactical grammar information or treating features with similar meanings as different. To solve these problems, this paper proposes an enhanced feature extraction and refinement method called FEROM that effectively extracts correct features from review data by exploiting both grammatical properties and semantic characteristics of feature words and refines the features by recognizing and merging similar ones. A series of experiments performed on actual online review data demonstrated that FEROM is highly effective at extracting and refining features for analyzing customer review data and eventually contributes to accurate and functional opinion mining.
GCC2Verilog Compiler Toolset for Complete Translation of C Programming Language into Verilog HDL
Huong, Giang Nguyen Thi ; Kim, Seon-Wook ;
ETRI Journal, volume 33, issue 5, 2011, Pages 731~740
DOI : 10.4218/etrij.11.0110.0654
Reconfigurable computing using a field-programmable gate-array (FPGA) device has become a promising solution in system design because of its power efficiency and design flexibility. To bring the benefit of FPGA to many application programmers, there has been intensive research about automatic translation from high-level programming languages (HLL) such as C and C++ into hardware. However, the large gap of syntaxes and semantics between hardware and software programming makes the translation challenging. In this paper, we introduce a new approach for the translation by using the widely used GCC compiler. By simply adding a hardware description language (HDL) backend to the existing state-of- the-art compiler, we could minimize an effort to implement the translator while supporting full features of HLL in the HLL-to-HDL translation and providing high performance. Our translator, called GCC2Verilog, was implemented as the GCC's cross compiler targeting at FPGAs instead of microprocessor architectures. Our experiment shows that we could achieve a speedup of up to 34 times and 17 times on average with 4-port memory over PICO microprocessor execution in selected EEMBC benchmarks.
Speaker Tracking Using Eigendecomposition and an Index Tree of Reference Models
Moattar, Mohammad Hossein ; Homayounpour, Mohammad Mehdi ;
ETRI Journal, volume 33, issue 5, 2011, Pages 741~751
DOI : 10.4218/etrij.11.0110.0686
This paper focuses on online speaker tracking for telephone conversations and broadcast news. Since the online applicability imposes some limitations on the tracking strategy, such as data insufficiency, a reliable approach should be applied to compensate for this shortage. In this framework, a set of reference speaker models are used as side information to facilitate online tracking. To improve the indexing accuracy, adaptation approaches in eigenvoice decomposition space are proposed in this paper. We believe that the eigenvoice adaptation techniques would help to embed the speaker space in the models and hence enrich the generality of the selected speaker models. Also, an index structure of the reference models is proposed to speed up the search in the model space. The proposed framework is evaluated on 2002 Rich Transcription Broadcast News and Conversational Telephone Speech corpus as well as a synthetic dataset. The indexing errors of the proposed framework on telephone conversations, broadcast news, and synthetic dataset are 8.77%, 9.36%, and 12.4%, respectively. Using the index tree structure approach, the run time of the proposed framework is improved by 22%.
A CMOS 5.4/3.24-Gbps Dual-Rate CDR with Enhanced Quarter-Rate Linear Phase Detector
Yoo, Jae-Wook ; Kim, Tae-Ho ; Kim, Dong-Kyun ; Kang, Jin-Ku ;
ETRI Journal, volume 33, issue 5, 2011, Pages 752~758
DOI : 10.4218/etrij.11.0110.0578
This paper presents a clock and data recovery circuit that supports dual data rates of 5.4 Gbps and 3.24 Gbps for DisplayPort v1.2 sink device. A quarter-rate linear phase detector (PD) is used in order to mitigate high speed circuit design effort. The proposed linear PD results in better jitter performance by increasing up and down pulse widths of the PD and removes dead-zone problem of charge pump circuit. A voltage-controlled oscillator is designed with a 'Mode' switching control for frequency selection. The measured RMS jitter of recovered clock signal is 2.92 ps, and the peak-to-peak jitter is 24.89 ps under
bit-long pseudo-random bit sequence at the bitrate of 5.4 Gbps. The chip area is 1.0 mm
1.3 mm, and the power consumption is 117 mW from a 1.8 V supply using 0.18
Cooperative Hybrid-ARQ Protocols: Unified Frameworks for Protocol Analysis
Byun, Il-Mu ; Kim, Kwang-Soon ;
ETRI Journal, volume 33, issue 5, 2011, Pages 759~769
DOI : 10.4218/etrij.11.0110.0630
Cooperative hybrid-automatic repeat request (HARQ) protocols, which can exploit the spatial and temporal diversities, have been widely studied. The efficiency of cooperative HARQ protocols is higher than that of cooperative protocols because retransmissions are only performed when necessary. We classify cooperative HARQ protocols as three decode-and-forward-based HARQ (DF-HARQ) protocols and two amplified-and-forward-based HARQ (AF-HARQ) protocols. To compare these protocols and obtain the optimum parameters, two unified frameworks are developed for protocol analysis. Using the frameworks, we can evaluate and compare the maximum throughput and outage probabilities according to the SNR, the relay location, and the delay constraint. From the analysis we can see that the maximum achievable throughput of the DF-HARQ protocols can be much greater than that of the AF-HARQ protocols due to the incremental redundancy transmission at the relay.
An Efficient Network Attack Visualization Using Security Quad and Cube
Chang, Beom-Hwan ; Jeong, Chi-Yoon ;
ETRI Journal, volume 33, issue 5, 2011, Pages 770~779
DOI : 10.4218/etrij.11.0110.0570
Security quad and cube (SQC) is a network attack analyzer that is capable of aggregating many different events into a single significant incident and visualizing these events in order to identify suspicious or illegitimate behavior. A network administrator recognizes network anomalies by analyzing the traffic data and alert messages generated in the security devices; however, it takes a lot of time to inspect and analyze them because the security devices generate an overwhelming amount of logs and security events. In this paper, we propose SQC, an efficient method for analyzing network security through visualization. The proposed method monitors anomalies occurring in an entire network and displays detailed information of the attacks. In addition, by providing a detailed analysis of network attacks, this method can more precisely detect and distinguish them from normal events.
An Efficient DPA Countermeasure for the
Pairing Algorithm over GF(
) Based on Random Value Addition
Seo, Seog-Chung ; Han, Dong-Guk ; Hong, Seok-Hie ;
ETRI Journal, volume 33, issue 5, 2011, Pages 780~790
DOI : 10.4218/etrij.11.0110.0597
This paper presents an efficient differential power analysis (DPA) countermeasure for the
pairing algorithm over GF(
). The proposed algorithm is based on a random value addition (RVA) mechanism. An RVA-based DPA countermeasure for the
pairing computation over GF(
) was proposed in 2008. This paper examines the security of this RVA-based DPA countermeasure and defines the design principles for making the countermeasure more secure. Finally, the paper proposes an efficient RVA-based DPA countermeasure for the secure computation of the
pairing over GF(
). The proposed countermeasure not only overcomes the security flaws in the previous RVAbased method but also exhibits the enhanced performance. Actually, on the 8-bit ATmega128L and 16-bit MSP430 processors, the proposed method can achieve almost 39% and 43% of performance improvements, respectively, compared with the best-known countermeasure.
A Secure Key Predistribution Scheme for WSN Using Elliptic Curve Cryptography
Rajendiran, Kishore ; Sankararajan, Radha ; Palaniappan, Ramasamy ;
ETRI Journal, volume 33, issue 5, 2011, Pages 791~801
DOI : 10.4218/etrij.11.0110.0665
Security in wireless sensor networks (WSNs) is an upcoming research field which is quite different from traditional network security mechanisms. Many applications are dependent on the secure operation of a WSN, and have serious effects if the network is disrupted. Therefore, it is necessary to protect communication between sensor nodes. Key management plays an essential role in achieving security in WSNs. To achieve security, various key predistribution schemes have been proposed in the literature. A secure key management technique in WSN is a real challenging task. In this paper, a novel approach to the above problem by making use of elliptic curve cryptography (ECC) is presented. In the proposed scheme, a seed key, which is a distinct point in an elliptic curve, is assigned to each sensor node prior to its deployment. The private key ring for each sensor node is generated using the point doubling mathematical operation over the seed key. When two nodes share a common private key, then a link is established between these two nodes. By suitably choosing the value of the prime field and key ring size, the probability of two nodes sharing the same private key could be increased. The performance is evaluated in terms of connectivity and resilience against node capture. The results show that the performance is better for the proposed scheme with ECC compared to the other basic schemes.
Package-Platformed Linear/Circular Polarization Reconfigurable Antenna Using an Integrated Silicon RF MEMS Switch
Hyeon, Ik-Jae ; Jung, Tony J. ; Lim, Sung-Joon ; Baek, Chang-Wook ;
ETRI Journal, volume 33, issue 5, 2011, Pages 802~805
DOI : 10.4218/etrij.11.0210.0422
This letter presents a K-band polarization reconfigurable antenna integrated with a silicon radio frequency MEMS switch into the form of a compact package. The proposed antenna can change its state from linear polarization (LP) to circular polarization (CP) by actuating the MEMS switch, which controls the configuration of the coupling ring slot. Low-loss quartz is used for a radiating patch substrate and at the same time for a packaging lid by stacking it onto the MEMS substrate, which can increase the system integrity. The fabricated antenna shows broadband impedance matching and exhibits high axial ratios better than 15 dB in the LP and small axial ratios in the CP, with a minimum value of 0.002 dB at 20.8 GHz in the K-band.
Least Square Channel Estimation for Two-Way Relay MIMO OFDM Systems
Fang, Zhaoxi ; Shi, Jiong ;
ETRI Journal, volume 33, issue 5, 2011, Pages 806~809
DOI : 10.4218/etrij.11.0210.0424
This letter considers the channel estimation for two-way relay MIMO OFDM systems. A least square (LS) channel estimation algorithm under block-based training is proposed. The mean square error (MSE) of the LS channel estimate is computed, and the optimal training sequences with respect to this MSE are derived. Some numerical examples are presented to evaluate the performance of the proposed channel estimation method.
Widely Tunable 1.55-
Detuned Dual-Mode Laser Diode for Compact Continuous-Wave THz Emitter
Kim, Nam-Je ; Leem, Young-Ahn ; Ko, Hyun-Sung ; Jeon, Min-Yong ; Lee, Chul-Wook ; Han, Sang-Pil ; Lee, Dong-Hun ; Park, Kyung-Hyun ;
ETRI Journal, volume 33, issue 5, 2011, Pages 810~813
DOI : 10.4218/etrij.11.0210.0429
We report the use of a widely tunable detuned dual-mode laser diode (DML) as a compact and portable continuous-wave THz emitter. The wavelength difference between the two lasing modes of this DML can be tuned from 2.4 nm to 9.3 nm by using integrated microheaters. The power difference between these modes is less than 1 dB, and the side-mode suppression ratio is greater than 30 dB over the entire tuning range.
DZDC Coefficient Distributions for P-Frames in H.264/AVC
Wu, Wei ; Song, Bin ;
ETRI Journal, volume 33, issue 5, 2011, Pages 814~817
DOI : 10.4218/etrij.11.0210.0461
In this letter, the distributions of direct current (DC) coefficients for P-frames in H.264/AVC are analyzed, and the distortion model of the Gaussian source under the quantization of the dead-zone plus-uniform threshold quantization with uniform reconstruction quantizer is derived. Experimental results show that the DC coefficients of P-frames are best approximated by the Laplacian distribution and the Gaussian distribution at small quantization step sizes and at large quantization step sizes, respectively.
A D-Band Balanced Subharmonically-Pumped Resistive Mixer Based on 100-nm mHEMT Technology
Campos-Roca, Y. ; Tessmann, A. ; Massler, H. ; Leuther, A. ;
ETRI Journal, volume 33, issue 5, 2011, Pages 818~821
DOI : 10.4218/etrij.11.0210.0466
A D-band subharmonically-pumped resistive mixer has been designed, processed, and experimentally tested. The circuit is based on a
power divider structure consisting of a Lange coupler followed by a
/4 transmission line (at local oscillator (LO) frequency). This monolithic microwave integrated circuit (MMIC) has been realized in coplanar waveguide technology by using an InAlAs/InGaAs-based metamorphic high electron mobility transistor process with 100-nm gate length. The MMIC achieves a measured conversion loss between 12.5 dB and 16 dB in the radio frequency bandwidth from 120 GHz to 150 GHz with 4-dBm LO drive and an intermediate frequency of 100 MHz. The input 1-dB compression point and IIP3 were simulated to be 2 dBm and 13 dBm, respectively.
Asynchronous 2-Phase Protocol Based on Ternary Encoding for On-Chip Interconnect
Oh, Myeong-Hoon ; Kim, Seong-Woon ;
ETRI Journal, volume 33, issue 5, 2011, Pages 822~825
DOI : 10.4218/etrij.11.0211.0063
Level-encoded dual-rail (LEDR) has been widely used in onchip asynchronous interconnects supporting a 2-phase handshake protocol. However, it inevitably requires 2N wires for N-bit data transfers. Encoder and decoder circuits that perform an asynchronous 2-phase handshake protocol with only N wires for N-bit data transfers are presented for on-chip global interconnects. Their fundamentals are based on a ternary encoding scheme using current-mode multiple valued logics. Using 0.25
CMOS technologies, the maximum reduction ratio of the proposed circuits, compared with LEDR in terms of power-delay product, was measured as 39.5% at a wire length of 10 mm and data rate of 100 MHz.
SybilBF: Defending against Sybil Attacks via Bloom Filters
Wu, Hengkui ; Yang, Dong ; Zhang, Hongke ;
ETRI Journal, volume 33, issue 5, 2011, Pages 826~829
DOI : 10.4218/etrij.11.0210.0431
Distributed systems particularly suffer from Sybil attacks, where a malicious user creates numerous bogus nodes to influence the functions of the system. In this letter, we propose a Bloom filter-based scheme, SybilBF, to fight against Sybil attacks. A Bloom filter presents a set of Sybil nodes according to historical behavior, which can be disseminated to at least n (e-1)/e honest nodes. Our evaluation shows that SybilBF outperforms state of the art mechanisms improving SybilLimit by a factor of (1/e)