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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
Selecting the target year
Codebook-Based Precoding for SDMA-OFDMA with Spectrum Sharing
Jo, Han-Shin ;
ETRI Journal, volume 33, issue 6, 2011, Pages 831~840
DOI : 10.4218/etrij.11.0111.0078
This paper focuses on codebook-based precoding for space-division multiple access/orthogonal frequency-division multiple access (SDMA-OFDMA) systems aiming to guarantee high throughput for their users as well as to mitigate interference to fixed satellite service (FSS). A systematic design of SDMA codebook for subband-based OFDMA is proposed, which forms multiple orthogonal beams with common spatial null in the direction of a victim FSS earth station (ES). The design enables both transmitter and receiver to independently construct identical codebook by sharing only on the direction angle of an FSS ES, which takes fewer overhead bits than Gram-Schmidt process, a general method satisfying our design criterion. A system-level throughput evaluation shows that the proposed precoding provides superior performance over existing spectrum sharing method, that is, subband deactivation. The spectrum sharing analysis shows that the proposed precoding, even with an estimation error of the direction angles of an FSS ES, causes lower interference than existing precoding, knockdown precoding.
SNR Enhancement Algorithm Using Multiple Chirp Symbols with Clock Drift for Accurate Ranging
Jang, Seong-Hyun ; Kim, Yeong-Sam ; Yoon, Sang-Hun ; Chong, Jong-Wha ;
ETRI Journal, volume 33, issue 6, 2011, Pages 841~848
DOI : 10.4218/etrij.11.0111.0013
A signal-to-noise ratio (SNR) enhancement algorithm using multiple chirp symbols with clock drift is proposed for accurate ranging. Improvement of the ranging performance can be achieved by using the multiple chirp symbols according to Cramer-Rao lower bound; however, distortion caused by clock drift is inevitable practically. The distortion induced by the clock drift is approximated as a linear phase term, caused by carrier frequency offset, sampling time offset, and symbol time offset. SNR of the averaged chirp symbol obtained from the proposed algorithm based on the phase derotation and the symbol averaging is enhanced. Hence, the ranging performance is improved. The mathematical analysis of the SNR enhancement agrees with the simulations.
New Elements Concentrated Planar Fractal Antenna Arrays for Celestial Surveillance and Wireless Communications
Jabbar, Ahmed Najah ;
ETRI Journal, volume 33, issue 6, 2011, Pages 849~856
DOI : 10.4218/etrij.11.0111.0036
This research introduces three new fractal array configurations that have superior performance over the well-known Sierpinski fractal array. These arrays are based on the fractal shapes Dragon, Twig, and a new shape which will be called Flap fractal. Their superiority comes from the low side lobe level and/or the wide angle between the main lobe and the side lobes, which improves the signal-to-intersymbol interference and signal-to-noise ratio. Their performance is compared to the known array configurations: uniform, random, and Sierpinski fractal arrays.
Energy-Efficient Adaptive Dynamic Sensor Scheduling for Target Monitoring in Wireless Sensor Networks
Zhang, Jian ; Wu, Cheng-Dong ; Zhang, Yun-Zhou ; Ji, Peng ;
ETRI Journal, volume 33, issue 6, 2011, Pages 857~863
DOI : 10.4218/etrij.11.0111.0027
Due to uncertainties in target motion and randomness of deployed sensor nodes, the problem of imbalance of energy consumption arises from sensor scheduling. This paper presents an energy-efficient adaptive sensor scheduling for a target monitoring algorithm in a local monitoring region of wireless sensor networks. Owing to excessive scheduling of an individual node, one node with a high value generated by a decision function is preferentially selected as a tasking node to balance the local energy consumption of a dynamic clustering, and the node with the highest value is chosen as the cluster head. Others with lower ones are in reserve. In addition, an optimization problem is derived to satisfy the problem of sensor scheduling subject to the joint detection probability for tasking sensors. Particles of the target in particle filter algorithm are resampled for a higher tracking accuracy. Simulation results show this algorithm can improve the required tracking accuracy, and nodes are efficiently scheduled. Hence, there is a 41.67% savings in energy consumption.
Characterization of a Hybrid Cu Paste as an Isotropic Conductive Adhesive
Eom, Yong-Sung ; Choi, Kwang-Seong ; Moon, Seok-Hwan ; Park, Jun-Hee ; Lee, Jong-Hyun ; Moon, Jong-Tae ;
ETRI Journal, volume 33, issue 6, 2011, Pages 864~870
DOI : 10.4218/etrij.11.0110.0520
As an isotropic conductive adhesive, that is, a hybrid Cu paste composed of Cu powder, solder powder, and a fluxing resin system, has been quantitatively characterized. The mechanism of an electrical connection based on a novel concept of electrical conduction is experimentally characterized using an analysis of a differential scanning calorimeter and scanning electron microscope energy-dispersive X-ray spectroscopy. The oxide on the metal surface is sufficiently removed with an increase in temperature, and intermetallic compounds between the Cu and melted solder are simultaneously generated, leading to an electrical connection. The reliability of the hybrid Cu paste is experimentally identified and compared with existing Ag paste. As an example of a practical application, the hybrid Cu paste is used for LED packaging, and its electrical and thermal performances are compared with the commercialized Ag paste. In the present research, it is proved that, except the optical function, the electrical and thermal performances are similar to pre-existing Ag paste. The hybrid Cu paste could be used as an isotropic conductive adhesive due to its low production cost.
Adaptive Kernel Function of SVM for Improving Speech/Music Classification of 3GPP2 SMV
Lim, Chung-Soo ; Chang, Joon-Hyuk ;
ETRI Journal, volume 33, issue 6, 2011, Pages 871~879
DOI : 10.4218/etrij.11.0110.0780
Because a wide variety of multimedia services are provided through personal wireless communication devices, the demand for efficient bandwidth utilization becomes stronger. This demand naturally results in the introduction of the variable bitrate speech coding concept. One exemplary work is the selectable mode vocoder (SMV) that supports speech/music classification. However, because it has severe limitations in its classification performance, a couple of works to improve speech/music classification by introducing support vector machines (SVMs) have been proposed. While these approaches significantly improved classification accuracy, they did not consider correlations commonly found in speech and music frames. In this paper, we propose a novel and orthogonal approach to improve the speech/music classification of SMV codec by adaptively tuning SVMs based on interframe correlations. According to the experimental results, the proposed algorithm yields improved results in classifying speech and music within the SMV framework.
Low-Power Cool Bypass Switch for Hot Spot Prevention in Photovoltaic Panels
Pennisi, Salvatore ; Pulvirenti, Francesco ; Scala, Amedeo La ;
ETRI Journal, volume 33, issue 6, 2011, Pages 880~886
DOI : 10.4218/etrij.11.0110.0744
With the introduction of high-current 8-inch solar cells, conventional Schottky bypass diodes, usually adopted in photovoltaic (PV) panels to prevent the hot spot phenomenon, are becoming ineffective as they cause relatively high voltage drops with associated undue power consumption. In this paper, we present the architecture of an active circuit that reduces the aforementioned power dissipation by profitably replacing the bypass diode through a power MOS switch with its embedded driving circuitry. Experimental prototypes were fabricated and tested, showing that the proposed solution allows a reduction of the power dissipation by more than 70% compared to conventional Schottky diodes. The whole circuit does not require a dedicated DC power and is fully compatible with standard CMOS technologies. This enables its integration, even directly on the panel, thereby opening new scenarios for next generation PV systems.
Polymer Dielectrics and Orthogonal Solvent Effects for High-Performance Inkjet-Printed Top-Gated P-Channel Polymer Field-Effect Transistors
Baeg, Kang-Jun ; Khim, Dong-Yoon ; Jung, Soon-Won ; Koo, Jae-Bon ; You, In-Kyu ; Nah, Yoon-Chae ; Kim, Dong-Yu ; Noh, Yong-Young ;
ETRI Journal, volume 33, issue 6, 2011, Pages 887~896
DOI : 10.4218/etrij.11.0111.0321
We investigated the effects of a gate dielectric and its solvent on the characteristics of top-gated organic field-effect transistors (OFETs). Despite the rough top surface of the inkjet-printed active features, the charge transport in an OFET is still favorable, with no significant degradation in performance. Moreover, the characteristics of the OFETs showed a strong dependency on the gate dielectrics used and its orthogonal solvents. Poly(3-hexylthiophene) OFETs with a poly(methyl methacrylate) dielectric showed typical p-type OFET characteristics. The selection of gate dielectric and solvent is very important to achieve high-performance organic electronic circuits.
A Hybrid Audio
Modulator with dB-Linear Gain Control Function
Kim, Yi-Gyeong ; Cho, Min-Hyung ; Kim, Bong-Chan ; Kwon, Jong-Kee ;
ETRI Journal, volume 33, issue 6, 2011, Pages 897~903
DOI : 10.4218/etrij.11.0111.0293
modulator for audio applications is presented in this paper. The pulse generator for digital-to-analog converter alleviates the requirement of the external clock jitter and calibrates the coefficient variation due to a process shift and temperature changes. The input resistor network in the first integrator offers a gain control function in a dB-linear fashion. Also, careful chopper stabilization implementation using return-to-zero scheme in the first continuous-time integrator minimizes both the influence of flicker noise and inflow noise due to chopping. The chip is implemented in a 0.13
CMOS technology (I/O devices) and occupies an active area of 0.37
modulator achieves a dynamic range (A-weighted) of 97.8 dB and a peak signal-to-noise-plus-distortion ratio of 90.0 dB over an audio bandwidth of 20 kHz with a 4.4 mW power consumption from 3.3 V. Also, the gain of the modulator is controlled from -9.5 dB to 8.5 dB, and the performance of the modulator is maintained up to 5 nsRMS external clock jitter.
A Die-Selection Method Using Search-Space Conditions for Yield Enhancement in 3D Memory
Lee, Joo-Hwan ; Park, Ki-Hyun ; Kang, Sung-Ho ;
ETRI Journal, volume 33, issue 6, 2011, Pages 904~913
DOI : 10.4218/etrij.11.0111.0108
Three-dimensional (3D) memories using through-silicon vias (TSVs) as vertical buses across memory layers will likely be the first commercial application of 3D integrated circuit technology. The memory dies to stack together in a 3D memory are selected by a die-selection method. The conventional die-selection methods do not result in a high-enough yields of 3D memories because 3D memories are typically composed of known-good-dies (KGDs), which are repaired using self-contained redundancies. In 3D memory, redundancy sharing between neighboring vertical memory dies using TSVs is an effective strategy for yield enhancement. With the redundancy sharing strategy, a known-bad-die (KBD) possibly becomes a KGD after bonding. In this paper, we propose a novel die-selection method using KBDs as well as KGDs for yield enhancement in 3D memory. The proposed die-selection method uses three search-space conditions, which can reduce the search space for selecting memory dies to manufacture 3D memories. Simulation results show that the proposed die-selection method can significantly improve the yield of 3D memories in various fault distributions.
Text-Independent Speaker Verification Using Variational Gaussian Mixture Model
Moattar, Mohammad Hossein ; Homayounpour, Mohammad Mehdi ;
ETRI Journal, volume 33, issue 6, 2011, Pages 914~923
DOI : 10.4218/etrij.11.0110.0684
This paper concerns robust and reliable speaker model training for text-independent speaker verification. The baseline speaker modeling approach is the Gaussian mixture model (GMM). In text-independent speaker verification, the amount of speech data may be different for speakers. However, we still wish the modeling approach to perform equally well for all speakers. Besides, the modeling technique must be least vulnerable against unseen data. A traditional approach for GMM training is expectation maximization (EM) method, which is known for its overfitting problem and its weakness in handling insufficient training data. To tackle these problems, variational approximation is proposed. Variational approaches are known to be robust against overtraining and data insufficiency. We evaluated the proposed approach on two different databases, namely KING and TFarsdat. The experiments show that the proposed approach improves the performance on TFarsdat and KING databases by 0.56% and 4.81%, respectively. Also, the experiments show that the variationally optimized GMM is more robust against noise and the verification error rate in noisy environments for TFarsdat dataset decreases by 1.52%.
Probabilistic Support Vector Machine Localization in Wireless Sensor Networks
Samadian, Reza ; Noorhosseini, Seyed Majid ;
ETRI Journal, volume 33, issue 6, 2011, Pages 924~934
DOI : 10.4218/etrij.11.0110.0692
Sensor networks play an important role in making the dream of ubiquitous computing a reality. With a variety of applications, sensor networks have the potential to influence everyone's life in the near future. However, there are a number of issues in deployment and exploitation of these networks that must be dealt with for sensor network applications to realize such potential. Localization of the sensor nodes, which is the subject of this paper, is one of the basic problems that must be solved for sensor networks to be effectively used. This paper proposes a probabilistic support vector machine (SVM)-based method to gain a fairly accurate localization of sensor nodes. As opposed to many existing methods, our method assumes almost no extra equipment on the sensor nodes. Our experiments demonstrate that the probabilistic SVM method (PSVM) provides a significant improvement over existing localization methods, particularly in sparse networks and rough environments. In addition, a post processing step for PSVM, called attractive/repulsive potential field localization, is proposed, which provides even more improvement on the accuracy of the sensor node locations.
Privacy-Preserving H.264 Video Encryption Scheme
Choi, Su-Gil ; Han, Jong-Wook ; Cho, Hyun-Sook ;
ETRI Journal, volume 33, issue 6, 2011, Pages 935~944
DOI : 10.4218/etrij.11.0110.0644
As a growing number of individuals are exposed to surveillance cameras, the need to prevent captured videos from being used inappropriately has increased. Privacy-related information can be protected through video encryption during transmission or storage, and several algorithms have been proposed for such purposes. However, the simple way of evaluating the security by counting the number of brute-force trials is not proper for measuring the security of video encryption algorithms, considering that attackers can devise specially crafted attacks for specific purposes by exploiting the characteristics of the target video codec. In this paper, we introduce a new attack for recovering contour information from encrypted H.264 video. The attack can thus be used to extract face outlines for the purpose of personal identification. We analyze the security of previous video encryption schemes against the proposed attack and show that the security of these schemes is lower than expected in terms of privacy protection. To enhance security, an advanced block shuffling method is proposed, an analysis of which shows that it is more secure than the previous method and can be an improvement against the proposed attack.
An Efficient Time-Frequency Representation for Parametric-Based Audio Object Coding
Beack, Seung-Kwon ; Lee, Tae-Jin ; Kim, Min-Je ; Kang, Kyeong-Ok ;
ETRI Journal, volume 33, issue 6, 2011, Pages 945~948
DOI : 10.4218/etrij.11.0211.0007
Object-based audio coding can provide new music applications with interactivity. To efficiently compress a lot of target audio objects, a subband-based parametric coding scheme has been adopted for MPEG spatial audio object coding. In this letter, the time-frequency (T/F) subband analysis structure is investigated. A reconfigured T/F structure is also proposed to enhance the generating performance of sound scenes such as 'karaoke' and 'solo' play in interactive music scenarios. From the experimental results, it was confirmed that the proposed scheme remarkably improves the SNR and sound quality.
Simple Detection Based on Soft-Limiting for Binary Transmission in a Mixture of Generalized Normal-Laplace Distributed Noise and Gaussian Noise
Kim, Sang-Choon ;
ETRI Journal, volume 33, issue 6, 2011, Pages 949~952
DOI : 10.4218/etrij.11.0211.0026
In this letter, a simplified suboptimum receiver based on soft-limiting for the detection of binary antipodal signals in non-Gaussian noise modeled as a generalized normal-Laplace (GNL) distribution combined with Gaussian noise is presented. The suboptimum receiver has low computational complexity. Furthermore, when the number of diversity branches is small, its performance is very close to that of the Neyman-Pearson optimum receiver based on the probability density function obtained by the Fourier inversion of the characteristic function of the GNL-plus-Gaussian distribution.
A Novel Dual-Mode Bandpass Filter Based on a Defected Waveguide Resonator
Guan, Xuehui ; Fu, Wei ; Liu, Haiwen ; Ahn, Dal ; Lim, Jong-Sik ;
ETRI Journal, volume 33, issue 6, 2011, Pages 953~956
DOI : 10.4218/etrij.11.0211.0034
A novel dual-mode bandpass filter (BPF) using a dual spiral-shaped defected ground waveguide (DGW) resonator is proposed in this letter. The dual-mode characteristic of this filter is achieved by loading a defected T-shaped stub at the midline of the spiral-shaped DGW resonator. Also, non-orthogonal input and output feed-lines are adopted in the filter. Based on the compact DGW structure, a dual-mode BPF with central frequency of 1.5 GHz for the global positioning system is designed, fabricated, and measured. Measured results agree well with the predicted response and verify the proposed methodology.
Nash Bargaining Solution for RFID Frequency Interference
Lee, Dong-Yul ; Lee, Chae-Woo ;
ETRI Journal, volume 33, issue 6, 2011, Pages 957~960
DOI : 10.4218/etrij.11.0211.0037
We present a fair and efficient solution for selfish readers with the Nash bargaining solution (NBS) to mitigate the effects of RFID frequency interference. We compare the NBS with a solution derived by the max log-sum scheme that maximizes total utility and show that for selfish and rational readers, the NBS brings success in bargaining on resource allocation between readers unlike the max log-sum scheme, although the NBS has less total payoff compared to the max log-sum scheme.
Enhanced FCME Thresholding for Wavelet-Based Cognitive UWB over Fading Channels
Hosseini, Haleh ; Fisal, Norsheila ; Syed-Yusof, Sharifah Kamilah ;
ETRI Journal, volume 33, issue 6, 2011, Pages 961~964
DOI : 10.4218/etrij.11.0211.0046
The cognitive ultra-wideband (UWB) network detects interfering narrowband systems and adapts its configuration accordingly. An inherently adaptive and flexible candidate for cognitive UWB transmission is the wavelet packet multicarrier modulation (WPMCM). In this letter, we use an enhanced forward consecutive mean excision thresholding algorithm to tackle the noise uncertainty in the wavelet-based sensing of WPMCM systems, and mathematical analysis is performed for primary user channel fading. As a benchmark, we compare the proposed system with a conventional fast Fourier transformation-based system, and performance investigation proves significant improvements when primary and secondary links are subjected to multipath fading and noise.
A 1.485-Gbit/s Video Signal Transmission System at Carrier Frequencies of 240 GHz and 300 GHz
Chung, Tae-Jin ; Lee, Won-Hui ;
ETRI Journal, volume 33, issue 6, 2011, Pages 965~968
DOI : 10.4218/etrij.11.0211.0053
A 1.485-Gbit/s video signal transmission system at carrier frequencies of 240 GHz and 300 GHz was implemented and demonstrated. The radio frequency front-ends are composed of Schottky barrier diode subharmonic mixers (SHMs), frequency triplers, and diagonal horn antennas for the transmitter and receiver. Amplitude shift keying with an intermediate frequency of 5.94 GHz was utilized as the modulation scheme. A 1.485-Gbit/s video signal with a high-definition serial digital interface format was successfully transmitted over a wireless link distance of 4.2 m and displayed on an HDTV with a transmitted average output power of 20
at a 300-GHz system.
A Subthreshold CMOS RF Front-End Design for Low-Power Band-III T-DMB/DAB Receivers
Kim, Seong-Do ; Choi, Jang-Hong ; Lee, Joo-Hyun ; Koo, Bon-Tae ; Kim, Cheon-Soo ; Eum, Nak-Woong ; Yu, Hyun-Kyu ; Jung, Hee-Bum ;
ETRI Journal, volume 33, issue 6, 2011, Pages 969~972
DOI : 10.4218/etrij.11.0211.0055
This letter presents a CMOS RF front-end operating in a subthreshold region for low-power Band-III mobile TV applications. The performance and feasibility of the RF front-end are verified by integrating with a low-IF RF tuner fabricated in a 0.13-
CMOS technology. The RF front-end achieves the measured noise figure of 4.4 dB and a wide gain control range of 68.7 dB with a maximum gain of 54.7 dB. The power consumption of the RF front-end is 13.8 mW from a 1.2 V supply.
Efficient Maximum Power Tracking of Energy Harvesting Using a
Controller for Power Savings
Heo, Se-Wan ; Yang, Yil-Suk ; Lee, Jae-Woo ; Lee, Sang-Kyun ; Kim, Jong-Dae ;
ETRI Journal, volume 33, issue 6, 2011, Pages 973~976
DOI : 10.4218/etrij.11.0211.0149
This letter describes an efficient technique for maximum power point tracking (MPPT) of an energy harvesting device. It is based on controlling the device voltage at the point of maximum power. Using a microcontroller with a power saving technique, the MPPT algorithm maintains the maximum power with low power consumption. An experiment shows that the algorithm maximizes the energy transfer power using an energy management IC fabricated in a 0.18-
process. Compared to direct energy transfer to a battery, the proposed technique is more efficient for low-energy harvesting under variable conditions.
Subjective Listening Experiments on a Front and Rear Array-Based WFS System
Yoo, Jae-Hyoun ; Seo, Jeong-Il ; Shim, Hwan ; Chung, Hyun-Joo ; Sung, Koeng-Mo ; Kang, Kyeong-Ok ;
ETRI Journal, volume 33, issue 6, 2011, Pages 977~980
DOI : 10.4218/etrij.11.0210.0335
Wave field synthesis (WFS) has been gathering more and more attention recently due to its ability to perfectly reproduce an original sound field. However, to realize theoretically perfect WFS, a four-sided loudspeaker array that encloses the listener is required. However, it is difficult to build such a system except in large listening spaces, such as a theater or concert hall. In other words, if the listening space is a home, installing a side loudspeaker array is impractical. If the two side walls located to the left and right of the listener can be omitted, a setup using only front and rear loudspeaker arrays may be a solution. In this letter, we present a subjective listening experiment of sound localization/distance based on a WFS using a front and rear loudspeaker array system which is conducted on two listening points and shows average localization errors of
, while the average distance errors are -27% (0.5 m) and -29% (0.6 m), respectively.
Microstrip Lowpass Filter with Very Sharp Transition Band and Wide Stopband
Hayati, Mohsen ; Sheikhi, Akram ;
ETRI Journal, volume 33, issue 6, 2011, Pages 981~984
DOI : 10.4218/etrij.11.0210.0493
A novel lowpass filter with a very sharp transition band and wide stopband is proposed. The proposed filter is based on T-shaped patches which are etched in symmetrical structures and folded open stub. To obtain a wide stopband, we have used stub loaded semi-circle stepped-impedance structures. By designing the resonator with high inductance and capacitance, a very sharp transition band is achieved. The proposed filter has a 3-dB cutoff frequency at 2.37 GHz and a 40-dB rejection at 2.44 GHz. The stopband with an attenuation level better than -13.2 dB is up from 2.4 GHz to 16 GHz, and consequently we have reached the high and wide rejection in stopband with compact size. Good agreements between the simulated and the measured results are presented.
Dual-Transmission-Line Microstrip Equiripple Lowpass Filter with Sharp Roll-Off
Velidi, Vamsi Krishna ; Sanyal, Subrata ;
ETRI Journal, volume 33, issue 6, 2011, Pages 985~988
DOI : 10.4218/etrij.11.0210.0497
A novel application of a dual-transmission line is proposed to design a lowpass filter (LPF). The proposed structure uses only transmission line elements to produce an equiripple LPF response with sharp roll-off. Design equations are derived using a lossless transmission line model. Controlling the electrical lengths, three transmission-zeros are realized in the stopband to obtain a sharp roll-off rate and wide stopband bandwidth. A single unit microstrip LPF with a 3-dB cut-off frequency at 1.0 GHz having a roll-off of 135 dB/GHz along with a stopband bandwidth of 69.5% is designed for validation.
Fault Attack on a Point Blinding Countermeasure of Pairing Algorithms
Park, Jea-Hoon ; Sohn, Gyo-Yong ; Moon, Sang-Jae ;
ETRI Journal, volume 33, issue 6, 2011, Pages 989~992
DOI : 10.4218/etrij.11.0210.0483
Recently, Page and Vercauteren proposed a fault attack on pairing algorithms and two countermeasures against such an attack. The countermeasure uses either a random scalar or a random point to blind the input points. To defeat the countermeasure using a random point, we utilize the point addition formula on an elliptic curve. As a result, we successfully defeat the countermeasure using a random point.