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Kenji SUGIYAMA
2014 Volume E97.A Issue 2 Pages
490
Published: February 01, 2014
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Seiichiro NAITO, Ryo SHOHARA, Makoto KATSUMURA
Article type: INVITED PAPER
2014 Volume E97.A Issue 2 Pages
491-500
Published: February 01, 2014
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We investigated the filling-in (FI) of line segments at the Artificial Scotoma (AS) created by Motion Induced Blindness (MIB). The FI sensations for line segments were fairly similar to that of the natural Blind Spots (BS), though the geometrical configurations and luminance conditions on stimuli were substantially limited. The 2.5 degree thick black line segment was filled in after 6.5 degree diameter disk was disappeared by MIB. The thin lines, however, didn't fill in. We also obtained the pro and con evidences for the historical FI theory. The disappearance of the uniformly filled circles followed the general FI theory. On the other hand we found it controversial with the FI accounts that the concentric circles disappeared altogether. In the conventional MIB, the target figure disappears and re-appears in a stochastic and spontaneous manner. We devised the novel inducer for MIB so as to yield the synchronization of dis- and re-appearance of the targets with the motion of the inducers. The two stationary disks disappeared in an alternating manner by MIB effects. The subjects observed the background color after disappearance. The alternating disappearance of the two white disks provided the observers with the sensation of the Apparent Motion (AM) of the single disk which would be perceived as jumping up and down. The significant question was raised; did MIB precede AM? When the AM sensation was the case, the percept was not the disappearance but the motion of the single entity. The sensation of the motion provided the almost equivalent conditions to the motion stimuli over the natural BS. We summarized the issue whether the FI at AS by MIB was intrinsically equivalent to the phenomena on BS. The hierarchy of underlying mechanisms of AM and MIB was yet unknown, however, we rather proposed yet another high level motion perception mechanism.
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Lei SUN, Zhenyu LIU, Takeshi IKENAGA
Article type: PAPER
2014 Volume E97.A Issue 2 Pages
501-509
Published: February 01, 2014
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Scalable Video Coding (SVC) is an extension of H.264/AVC, aiming to provide the ability to adapt to heterogeneous networks or requirements. It offers great flexibility for bitstream adaptation in multi-point applications such as videoconferencing. However, transcoding between SVC and AVC is necessary due to the existence of legacy AVC-based systems. The straightforward re-encoding method requires great computational cost, and delay-sensitive applications like videoconferencing require much faster transcoding scheme. This paper proposes a 3-stage fast SVC-to-AVC transcoder with medium-grain quality scalability (MGS) for videoconferencing applications. Hierarchical-P structured SVC bitstream is transcoded into IPPP structured AVC bitstream with multiple reference frames. In the first stage, mode decision is accelerated by proposed SVC-to-AVC mode mapping scheme. In the second stage, INTER motion estimation is accelerated by an optimized motion vector (MV) conjunction method to predict the MV with a reduced search range. In the last stage, hadamard-based all zero block (AZB) detection is utilized for early termination. Simulation results show that proposed transcoder achieves very similar coding efficiency to the optimal result, but with averagely 89.6% computational time saving.
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Heming SUN, Dajiang ZHOU, Peilin LIU, Satoshi GOTO
Article type: PAPER
2014 Volume E97.A Issue 2 Pages
510-519
Published: February 01, 2014
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As a next-generation video compression standard, High Efficiency Video Coding (HEVC) achieves enhanced coding performance relative to prior standards such as H.264/AVC. In the new standard, the improved intra prediction plays an important role in bit rate saving. Meanwhile, it also involves significantly increased complexity, due to the adoption of a highly flexible coding unit structure and a large number of angular prediction modes. In this paper, we present a low-complexity intra prediction algorithm for HEVC. We first propose a fast preprocessing stage based on a simplified cost model. Based on its results, a fast prediction unit selection scheme reduces the number of prediction unit (PU) levels that requires fine processing from 5 to 2. To supply PU size decision with appropriate thresholds, a fast training method is also designed. Still based on the preprocessing results, an efficient mode selection scheme reduces the maximum number of angular modes to evaluate from 35 to 8. This achieves further algorithm acceleration by eliminating the necessity to perform fine Hadamard cost calculation. We also propose a 32×32 PU compensation scheme to alleviate the mismatch of cost functions for large transform units, which effectively improves coding performance for high-resolution sequences. In comparison with HM 7.0, the proposed algorithm achieves over 50% complexity reduction in terms of encoding time, with the corresponding bit rate increase lower than 2.0%. Moreover, the achieved complexity reduction is relatively stable and independent to sequence characteristics.
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Axel BEAUGENDRE, Satoshi GOTO
Article type: PAPER
2014 Volume E97.A Issue 2 Pages
520-529
Published: February 01, 2014
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Moving objects or more generally foreground objects are the simplest objects in the field of computer vision after the pixel. Indeed, a moving object can be defined by 4 integers only, either two pairs of coordinates or a pair of coordinates and the size. In fixed camera scenes, moving objects (or blobs) can be extracted quite easily but the methods to produce them are not able to tell if a blob corresponds to remaining background noise, a single target or if there is an occlusion between many target which are too close together thus creating a single blob resulting from the fusion of all targets. In this paper we propose an novel method to refine moving object detection results in order to get as many blobs as targets on the scene by using a tracking system for additional information. Knowing if a blob is at proximity of a tracker allows us to remove noise blobs, keep the rest and handle occlusions when there are more than one tracker on a blob. The results show that the refinement is an efficient tool to sort good blobs from noise blobs and accurate enough to perform a tracking based on moving objects. The tracking process is a resolution free system able to reach speed such as 20 000fps even for UHDTV sequences. The refinement process itself is in real time, running at more than 2000fps in difficult situations. Different tests are presented to show the efficiency of the noise removal and the reality of the independence of the refinement tracking system from the resolution of the videos.
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Hideaki TAKAHIRA, Ryouichi ISHIKAWA, Kei KIKUCHI, Tatsuya SHINKAWA, Mi ...
Article type: LETTER
2014 Volume E97.A Issue 2 Pages
530-533
Published: February 01, 2014
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We investigated subjects' gaze movement when reading E-books and compared it with that when reading traditional paper books. By examining the eye motion associated with the reader encountering new lines and new pages during reading, we found that each new line was completed with one saccade in both E-books and paper books, but E-books and paper books differed in saccade patterns when the reader encountered a new page. In E-books, a regular eye movement such as steady gaze to the next page's start position was repeated. In contrast, in paper books, there is no regularity in eye movement during this transition. It was shown that reading behavior is variable and depends on the individual.
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Kei KIKUCHI, Hideaki TAKAHIRA, Ryouichi ISHIKAWA, Eiki WAKAMATSU, Tats ...
Article type: LETTER
2014 Volume E97.A Issue 2 Pages
534-537
Published: February 01, 2014
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We developed a device to measure gaze and hand movement in a natural setting such as while reading a book on a train or bus. We examined what kind of cooperation exists among the head, eye and hand movements while subjects were reading a book held in the hand.
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Leida LI, Hancheng ZHU, Gaobo YANG
Article type: LETTER
2014 Volume E97.A Issue 2 Pages
538-542
Published: February 01, 2014
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This letter presents a new image quality metric using low order discrete orthogonal moments. The moment features are extracted in a block manner and the relative moment differences (RMD) are computed. A new exponential function based on RMD is proposed to generate the quality score. The performance of the proposed method is evaluated on public databases. Experimental results and comparisons demonstrate the efficiency of the proposed method.
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Yuta SHIRATORI, Izumi TAKAHASHI, Keisuke SANO, Yuki SHIBUTA, Mitsuho Y ...
Article type: LETTER
2014 Volume E97.A Issue 2 Pages
543-546
Published: February 01, 2014
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In a live 3D TV program, since a change and processing of an image is performed in real time, it is difficult to check depth perception in advance. From such a background, we made the trial 3D TV program where various visual effects were used and analyzed subject's vergence while viewing them.
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Kiyoshi NISHIYAMA
Article type: PAPER
Subject area: Digital Signal Processing
2014 Volume E97.A Issue 2 Pages
547-556
Published: February 01, 2014
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A method for efficiently estimating the time-varying spectra of nonstationary autoregressive (AR) signals is derived using an indefinite matrix-based sliding window fast linear prediction (ISWFLP). In the linear prediction, the indefinite matrix plays a very important role in sliding an exponentially weighted finite-length window over the prediction error samples. The resulting ISWFLP algorithm successively estimates the time-varying AR parameters of order
N at a computational complexity of
O(
N) per sample. The performance of the AR parameter estimation is superior to the performances of the conventional techniques, including the Yule-Walker, covariance, and Burg methods. Consequently, the ISWFLP-based AR spectral estimation method is able to rapidly track variations in the frequency components with a high resolution and at a low computational cost. The effectiveness of the proposed method is demonstrated by the spectral analysis results of a sinusoidal signal and a speech signal.
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Kazuki SHIOGAI, Naoto SASAOKA, Masaki KOBAYASHI, Isao NAKANISHI, James ...
Article type: PAPER
Subject area: Digital Signal Processing
2014 Volume E97.A Issue 2 Pages
557-564
Published: February 01, 2014
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Conventional adaptive notch filter based on an infinite impulse response (IIR) filter is well known. However, this kind of adaptive notch filter has a problem of stability due to its adaptive IIR filter. In addition, tap coefficients of this notch filter converge to solutions with bias error. In order to solve these problems, an adaptive notch filter using Fourier sine series (ANFF) is proposed. The ANFF is stable because an adaptive IIR filter is not used as an all-pass filter. Further, the proposed adaptive notch filter is robust enough to overcome effects of a disturbance signal, due to a structure of the notch filter based on an exponential filter and line symmetry of auto correlation.
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Shunsuke YAMAKI, Masahide ABE, Masayuki KAWAMATA
Article type: PAPER
Subject area: Digital Signal Processing
2014 Volume E97.A Issue 2 Pages
565-571
Published: February 01, 2014
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This paper derives the balanced realizations of second-order analog filters directly from the transfer function. Second-order analog filters are categorized into the following three cases: complex conjugate poles, distinct real poles, and multiple real poles. For each case, simple formulas are derived for the synthesis of the balanced realizations of second-order analog filters. As a result, we obtain closed form expressions of the balanced realizations of second-order analog filters.
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Hongqing ZHU, Meiyu DING, Daqi GAO
Article type: PAPER
Subject area: Digital Signal Processing
2014 Volume E97.A Issue 2 Pages
572-586
Published: February 01, 2014
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The
nth partial sums of a classical Fourier series have large oscillations near the jump discontinuities. This behaviour is the well-known Gibbs phenomenon. Recently, the inverse polynomial reconstruction method (IPRM) has been successfully implemented to reconstruct piecewise smooth functions by reducing the effects of the Gibbs phenomenon for Fourier series. This paper addresses the 2-D fractional Fourier series (FrFS) using the same approach used with the 1-D fractional Fourier series and finds that the Gibbs phenomenon will be observed in 1-D and 2-D fractional Fourier series expansions for functions at a jump discontinuity. The existing IPRM for resolution of the Gibbs phenomenon for 1-D and 2-D FrFS appears to be the same as that used for Fourier series. The proof of convergence provides theoretical basis for both 1-D and 2-D IPRM to remove Gibbs phenomenon. Several numerical examples are investigated. The results indicate that the IPRM method completely eliminates the Gibbs phenomenon and gives exact reconstruction results.
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Min Kook SONG, Jin Bae PARK, Young Hoon JOO
Article type: PAPER
Subject area: Systems and Control
2014 Volume E97.A Issue 2 Pages
587-596
Published: February 01, 2014
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This paper is concerned with exploring an extended approach for the stability analysis and synthesis for Markovian jump nonlinear systems (MJNLSs) via fuzzy control. The Takagi-Sugeno (T-S) fuzzy model is employed to represent the MJNLSs with incomplete transition description. In this paper, not all the elements of the rate transition matrices (RTMs), or probability transition matrices (PTMs) are assumed to be known. By fully considering the properties of the RTMs and PTMs, sufficient criteria of stability and stabilization is obtained in both continuous and discrete-time. Stabilization conditions with a mode-dependent fuzzy controller are derived for Markovian jump fuzzy systems in terms of linear matrix inequalities (LMIs), which can be readily solved by using existing LMI optimization techniques. Finally, illustrative numerical examples are provided to demonstrate the effectiveness of the proposed approach.
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Tsang-Chi KAN, Ying-Jung CHEN, Hung-Ming HONG, Shanq-Jang RUAN
Article type: PAPER
Subject area: VLSI Design Technology and CAD
2014 Volume E97.A Issue 2 Pages
597-605
Published: February 01, 2014
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Well designed redundant via-aware standard cells (SCs) can increase the redundant via1 insertion rate in cell-based designs. However, in conventional methods, manual- and visual-based checks are required to locate pins and tune the geometries of layouts. These tasks can be very time consuming and unreliable. In this work, an O(
Nlog
N) redundant via-aware standard cell optimization scheme is developed. The proposed method is an efficient layout check and optimization scheme that considers various redundant via configurations including the double-via and rectangle-via to shorten the design time for standard cells. The optimized SCs effectively increase the redundant via insertion rate, and in particular the insertion rate of via1 for both concurrent routing and post-layout optimization. Furthermore, an automatic layout checker and optimizer are more efficient in identifying expandable metal 1 pins in libraries that contain numerous cells than are conventional visual check and manual optimization. Therefore, the proposed scheme not only solves the problem of a low via1 insertion rate in nanometer regimes, but also provides an efficient layout optimizer for designing standard cells. Experimental results indicate that the optimized standard cells increase the double-via1 insertion rates by 21.9%.
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Ittetsu TANIGUCHI, Kohei AOKI, Hiroyuki TOMIYAMA, Praveen RAGHAVAN, Fr ...
Article type: PAPER
Subject area: VLSI Design Technology and CAD
2014 Volume E97.A Issue 2 Pages
606-615
Published: February 01, 2014
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A fast and accurate architecture exploration for high performance and low energy VLIW data-path is proposed. The main contribution is a method to find Pareto optimal FU structures, i.e., the optimal number of FUs and the best instruction assignment for each FU. The proposed architecture exploration method is based on GA and enables the effective exploration of vast solution space. Experimental results showed that proposed method was able to achieve fast and accurate architecture exploration. For most cases, the estimation error was less than 1%.
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Chin-Long WEY, Ping-Chang JUI, Gang-Neng SUNG
Article type: PAPER
Subject area: VLSI Design Technology and CAD
2014 Volume E97.A Issue 2 Pages
616-623
Published: February 01, 2014
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This study presents efficient algorithms for performing multiply-by-3 (3N) and divide-by-3 (N/3) operations with the additions and subtractions, respectively. No multiplications and divisions are needed. Full adder (FA) and full subtractor (FS) can be implemented to realize the N3 and N/3 operations, respectively. For fast hardware implementation, this paper introduces two basic cells UCA and UCS for 3N and N/3 operations, respectively. For 3N operation, the UCA-based ripple carry adder (RCA) and carry lookahead adder (CLA) designs are proposed and their speed performances are estimated based on the delay data of standard cell library in TSMC 0.18µm CMOS process. Results show that the 16-bit UCA-based RCA is about 3 times faster than the conventional FA-based RCA and even 25% faster than the FA-based CLA. The proposed 16-bit and 64-bit UCA-based CLAs are 62% and 36% faster than the conventional FA-based CLAs, respectively. For N/3 operations, ripple borrow subtractor (RBS) is also presented. The 16-bit UCS-based RBS is about 15.5% faster than the 16-bit FS-based RBS.
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S. R. MALATHI, P. SAKTHIVEL
Article type: PAPER
Subject area: Algorithms and Data Structures
2014 Volume E97.A Issue 2 Pages
624-631
Published: February 01, 2014
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Many discrete functions are often compactly represented by Decision Diagrams (DD). The main problem in the construction of decision diagrams is the space and time requirements. While constructing a decision diagram the memory requirement may grow exponentially with the function. Also, large numbers of temporary nodes are created while constructing the decision diagram for a function. Here the problem of reducing the number of temporary nodes is addressed with respect to the PLA specification format of a function, where the function is represented using a set of cubes. Usually a DD is constructed by recursively processing the input cubes in the PLA specification. The DD, representing a sub function, is specified by a single cube. This DD is merged with a master DD, which represents the entire previously processed cubes. Thus the master DD is constructed recursively, until all the cubes in the input cube set are processed. In this paper, an efficient method is proposed, which reorders and also partitions the cube set into unequal number of cubes per subset, in such a way that, the number of temporary nodes created and the number of logical operations done, during the merging of cubes with the master DD are reduced. This results in the reduction of space and time required for the construction of DDs to a remarkable extent.
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Daniel Johannes LOUW, Haruhiko KANEKO
Article type: PAPER
Subject area: Coding Theory
2014 Volume E97.A Issue 2 Pages
632-641
Published: February 01, 2014
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Single view distributed video coding (DVC) is a coding method that allows for the computational complexity of the system to be shifted from the encoder to the decoder. This property promotes the use of DVC in systems where processing power or energy use at the encoder is constrained. Examples include wireless devices and surveillance. This paper proposes a multi-hypothesis transform domain single-view DVC system that performs symbol level coding with a non-binary low-density parity-check code. The main contributions of the system relate to the methods used for combining multiple side information hypotheses at the decoder. The system also combines interpolation and extrapolation in the side information creation process to improve the performance of the system over larger group-of-picture sizes.
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Masato INOUE, Haruhiko KANEKO
Article type: PAPER
Subject area: Coding Theory
2014 Volume E97.A Issue 2 Pages
642-651
Published: February 01, 2014
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This paper proposes an adaptive marker coding (AMC) for correction of insertion/deletion/substitution errors. Unlike the conventional marker codings which select marker-bit values deterministically, the AMC adaptively reverses the first and last bits of each marker as well as bits surrounding the marker. Decoding is based on a forward-backward algorithm which takes into account the dependency of bit-values around the marker. Evaluation shows that, for a channel with insertion/deletion error probability 1.8×10
-2, the decoded BER of existing marker coding of rate 9/16 is 4.25×10
-3, while that of the proposed coding with the same code rate is 1.73×10
-3.
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Soon Young PARK, Jongsik PARK
Article type: PAPER
Subject area: Measurement Technology
2014 Volume E97.A Issue 2 Pages
652-660
Published: February 01, 2014
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In this paper, we present a new four parameter estimator of sampled sinusoidal signals that does not require iteration. Mathematically, the four parameters (frequency, phase, magnitude, and dc offset) of sinusoidal signals can be obtained when four data points are given. In general, the parameters have to be calculated with iteration since the equations are nonlinear. In this paper, we point out that the four parameters can be obtained analytically if the four data points given are measured using a fixed sampling interval. Analytical expressions for the four parameters are derived using the signal differences. Based on this analysis, we suggest an algorithm of estimating the four parameters from
N data samples corrupted by noise without iteration. When comparing with the IEEE-1057 method which is based on the least-square method, the proposed algorithm does not require the initial guess of the parameters for iteration and avoid the convergence problem. Also, the number of required numerical operations for estimation is fixed if
N is determined. As a result, the processing time of parameter estimation is much faster than the least-square method which has been confirmed by numerical simulations. Simulation results and the quantitative analysis show that the estimation error of the estimated parameters is less than 1.2 times the square root of the Cramer-Rao bounds when the signal to noise ratio is larger than 20dB.
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Ji-Hyun SONG, Hong-Sub AN, Sangmin LEE
Article type: LETTER
Subject area: Speech and Hearing
2014 Volume E97.A Issue 2 Pages
661-664
Published: February 01, 2014
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In this paper, we propose a robust speech/music classification algorithm to improve the performance of speech/music classification in the selectable mode vocoder (SMV) of 3GPP2 using deep belief networks (DBNs), which is a powerful hierarchical generative model for feature extraction and can determine the underlying discriminative characteristic of the extracted features. The six feature vectors selected from the relevant parameters of the SMV are applied to the visible layer in the proposed DBN-based method. The performance of the proposed algorithm is evaluated using the detection accuracy and error probability of speech and music for various music genres. The proposed algorithm yields better results when compared with the original SMV method and support vector machine (SVM) based method.
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Xunyong ZHANG, Chen HE, Lingge JIANG
Article type: LETTER
Subject area: Digital Signal Processing
2014 Volume E97.A Issue 2 Pages
665-668
Published: February 01, 2014
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In this paper, an effective per-antenna successive signal-to-leakage-plus-noise-ratio (PA-SSLNR) based precoding is proposed for multi-user multiple-input multiple-output (MIMO) broadcast channel. The signal-to-leakage-plus-noise-ratio (SLNR) of per-antenna is calculated only using the unknown leakages and the known leakages are cancelled at the transmit side by Tomlinson-Harashima Precoding (THP). The proposed scheme is different from per-user SSLNR. It does not need QR decomposition. The proposed precoding scheme is further improved by ordering antennas. Simulation results show that the proposed schemes exhibit a considerable bit error rate (BER) improvement over conventional SLNR scheme.
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Kayoko HAYASHI, Toru YAMAMOTO
Article type: LETTER
Subject area: Systems and Control
2014 Volume E97.A Issue 2 Pages
669-674
Published: February 01, 2014
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A data-driven controller has been proposed for nonlinear systems, and its effectiveness has been also shown. However, according to this control scheme, considerable large computation burden is required in on-line learning to update the database. The on-line limit its implementation in industrial processes. In this paper, a controller design scheme is proposed, which enables us to update the database in an off-line manner.
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Hiroshi NINOMIYA, Manabu KOBAYASHI, Yasuyuki MIURA, Shigeyoshi WATANAB ...
Article type: LETTER
Subject area: VLSI Design Technology and CAD
2014 Volume E97.A Issue 2 Pages
675-678
Published: February 01, 2014
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This letter describes a design methodology for an arithmetic logic unit (ALU) incorporating reconfigurability based on double-gate carbon nanotube field-effect transistors (DG-CNTFETs). The design of a DG-CNTFET with an ambipolar-property-based reconfigurable static logic circuit is simple and straightforward using an ambipolar binary decision diagram (Am-BDD), which represents the cornerstone for the automatic pass transistor logic (PTL) synthesis flows of ambipolar devices. In this work, an ALU with 16 functions is synthesized by the design methodology of a DG-CNTFET-based reconfigurable static logic circuit. Furthermore, it is shown that the proposed ALU is much more flexible and practical than a conventional DG-CNTFET-based reconfigurable ALU.
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Zu-ling CHANG, Dan-dan LI
Article type: LETTER
Subject area: Cryptography and Information Security
2014 Volume E97.A Issue 2 Pages
679-684
Published: February 01, 2014
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In this paper, one new class of quaternary generalized cyclotomic sequences with the period 2
pq over F
4 is established. The linear complexity of proposed sequences with the period 2
pq is determined. The results show that such sequences have high linear complexity.
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Xiangxue LI, Qingji ZHENG, Haifeng QIAN, Dong ZHENG, Kefei CHEN
Article type: LETTER
Subject area: Coding Theory
2014 Volume E97.A Issue 2 Pages
685-689
Published: February 01, 2014
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Given specified parameters, the number of check nodes, the expected girth and the variable node degrees, the Progressive Weight-Growth (PWG) algorithm is proposed to generate high rate low-density parity-check (LDPC) codes. Based on the theoretic foundation that is to investigate the girth impact by adding/removing variable nodes and edges of the Tanner graph, the PWG progressively increases column weights of the parity check matrix without violating the constraints defined by the given parameters. The analysis of the computational complexity and the simulation of code performance show that the LDPC codes by the PWG provide better or comparable performance in comparison with LDPC codes by some well-known methods (e.g., Mackay's random constructions, the PEG algorithm, and the bit-filling algorithm).
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Shuxia MA, Hongling ZHANG, Weidong JIN, Xianhua NIU
Article type: LETTER
Subject area: Coding Theory
2014 Volume E97.A Issue 2 Pages
690-693
Published: February 01, 2014
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Cyclic codes are a subclass of linear codes and have applications in consumer electronics, data storage systems, and communication systems as they have efficient encoding and decoding algorithms compared with the linear block codes. The objective of this letter is to present a new family of ternary cyclic codes with parameters
[3
m-1,3
m-1-2
m,4
], where
m is an odd integer. The proposed cyclic codes are optimal in the sense that their parameters meet the Sphere Packing bound.
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Tatsumi KONISHI
Article type: LETTER
Subject area: Communication Theory and Signals
2014 Volume E97.A Issue 2 Pages
694-697
Published: February 01, 2014
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We propose a 2 × 2 space-time block code based on a trace criterion for 64-quadrature amplitude modulation (QAM). We introduce a method to easily calculate the trace norm of a space-time code for 64-QAM, and propose a new space-time code searched by this method. The error rate performance of the proposed code is compared with that of the Alamouti code. By comparison of the theoretical upper bounds, the proposed space-time code is better than the Alamouti code, when the number of receiving antennas is more than one. Moreover, bit error rate performance of the proposed code is compared with maximum likelihood decoding on perfect channel state information Rayleigh fading channels by computer simulations. These results show the proposed code almost outperforms the Alamouti code when the number of receive antennas is more than one, and the increased number of receiving antennas with our code is a decided advantage.
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Sang-Uk PARK, Jung-Hyun PARK, Dong-Jo PARK
Article type: LETTER
Subject area: Communication Theory and Signals
2014 Volume E97.A Issue 2 Pages
698-703
Published: February 01, 2014
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This letter deals with a new cell clustering problem subject to signal-to-interference-plus-noise-ratio (SINR) constraints in uplink network MIMO systems, where multiple base stations (BSs) cooperate for joint processing as forming a cluster. We first prove that the SINRs of users in a certain cluster always increase monotonically as the cluster size increases when the receiver filter that maximizes the SINR is used. Using this result, we propose an efficient clustering algorithm to minimize the maximum number of cooperative BSs in a cluster. Simulation results show that the maximum number of cooperative BSs minimized by the proposed method is close to that minimized by the exhaustive search and the proposed scheme outperforms the conventional one in terms of the outage probability.
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Mochan YANG, Shannai WU, Hak-Seong KIM, Kyong-Bin SONG, Won Cheol LEE, ...
Article type: LETTER
Subject area: Communication Theory and Signals
2014 Volume E97.A Issue 2 Pages
704-707
Published: February 01, 2014
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A D2D (Device-to-Device) communication system needs to cope with inter-cell interference and other types of interferences between cellular network and D2D links. As a result, macro user equipments, particularly those located near a cell edge, will suffer from serious link performance degradation. We propose a novel interference avoidance mechanism assisted by the SRN (Shared Relay Node) in this letter. The SRN not only performs data re-transmission as a typical type-II relay, but has several newly defined features to avoid interference between cellular network and D2D links. The superb performance by the proposed scheme is evaluated through extensive system level simulations.
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Mitsuru ISHII, Daisuke TAKAGO
Article type: LETTER
Subject area: Mobile Information Network and Personal Communications
2014 Volume E97.A Issue 2 Pages
708-712
Published: February 01, 2014
Released on J-STAGE: February 01, 2014
JOURNAL
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We analyze the effect of the propagation of route request packets in ad hoc network routing protocols such as DSR and AODV. So far it has not been clear how the number density of route request packets depends on propagation and hop counts. By stochastic analysis, it is found that the collisions of route request packets can be avoided efficiently by adjusting the number of the relevant nodes in the early stages of propagation.
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Sewon HAN, Byung-Seo KIM
Article type: LETTER
Subject area: Mobile Information Network and Personal Communications
2014 Volume E97.A Issue 2 Pages
713-716
Published: February 01, 2014
Released on J-STAGE: February 01, 2014
JOURNAL
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MIL-STD-188-220 standard specifies protocols for narrowband and voice-based tactical communication devices. However, the future tactical communication devices require broadband services for accurate command and control. In this letter, the enhancement for MIL-STD-188-220-based systems is proposed for use over wideband channels. Unlike the operation defined in the standard, transmissions in Bump-Slots uses
P-Persistence method and give the higher p to stations experiencing longer delays. The proposed method is extensively evaluated and the performance enhancements are proved.
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Chia-Shao HUNG, Shanq-Jang RUAN
Article type: LETTER
Subject area: Image
2014 Volume E97.A Issue 2 Pages
717-718
Published: February 01, 2014
Released on J-STAGE: February 01, 2014
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Image binarization refers to convert gray-level images into binary ones, and many binarization algorithms have been developed. The related algorithms can be classified as either high quality computation or high speed performance. This letter presents an algorithm that ensures both benefits at the same time. The proposed algorithm intelligently segments input images into several sub-image, after which the sub-image binarization is performed independently. Experimental results reveal that our algorithm provides the appropriate quality with the medium speed.
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Zihan YU, Kiichi URAHAMA
Article type: LETTER
Subject area: Image
2014 Volume E97.A Issue 2 Pages
719-721
Published: February 01, 2014
Released on J-STAGE: February 01, 2014
JOURNAL
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We present an iterative method for inverse transform of nonlinear image processing. Its convergence is verified for image enhancement by an online software. We also show its application to amplification of the opacity in foggy or underwater images.
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