IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Online ISSN : 1745-1337
Print ISSN : 0916-8508

• Kakeru MATSUBARA, Shun KUROKI, Koki ITO, Kazushi SHIMADA, Kazuki MARUT ...
原稿種別: LETTER
論文ID: 2020EAL2124
発行日: 2021年
[早期公開] 公開日: 2021/02/25
ジャーナル 認証あり 早期公開

This letter expands the previously proposed High Time Resolution Carrier Interferometry (HTRCI) to estimate a larger amount of channel status information (CSI). HTRCI is based on a comb-type pilot symbol on OFDM and CSI for null subcarriers are interpolated by time-domain signal processing. In order to utilize such null pilot subcarriers for increasing estimable CSI, they should generally be separated in frequency-domain prior to estimation and interpolation processes. The main proposal is its separation scheme in conjunction with the HTRCI treatment of the temporal domain. Its effectiveness is verified by a pilot de-contamination on downlink two-cell MIMO transmission scenario. Binary error rate (BER) performance can be improved in comparison to conventional HTRCI and zero padding (ZP) which replaces the impulse response alias with zeros.

• Anis Ur REHMAN, Ken KIHARA, Sakuichi OHTSUKA
原稿種別: PAPER
論文ID: 2020EAP1110
発行日: 2021年
[早期公開] 公開日: 2021/02/25
ジャーナル 認証あり 早期公開

In daily reality, people often pay attention to several objects that change positions while being observed. In the laboratory, this process is investigated by a phenomenon known as multiple object tracking (MOT) which is a task that evaluates attentive tracking performance. Recent findings suggest that the attentional set for multiple moving objects whose depth changes in three dimensions from one plane to another is influenced by the initial configuration of the objects. When tracking objects, it is difficult for people to expand their attentional set to multiple-depth planes once attention has been focused on a single plane. However, less is known about people contracting their attentional set from multiple-depth planes to a single-depth plane. In two experiments, we examined tracking accuracy when four targets or four distractors, which were initially distributed on two planes, come together on one of the planes during an MOT task. The results from this study suggest that people have difficulty changing the depth range of their attention during attentive tracking, and attentive tracking performance depends on the initial attentional set based on the configuration prior to attentive tracking.

• Natsuki UENO, Shoichi KOYAMA, Hiroshi SARUWATARI
原稿種別: PAPER
論文ID: 2021EAP1004
発行日: 2021年
[早期公開] 公開日: 2021/02/25
ジャーナル 認証あり 早期公開

We propose a useful formulation for ill-posed inverse problems in Hilbert spaces with nonlinear clipping effects. Ill-posed inverse problems are often formulated as optimization problems, and nonlinear clipping effects may cause nonconvexity or nondifferentiability of the objective functions in the case of commonly used regularized least squares. To overcome these difficulties, we present a tractable formulation in which the objective function is convex and differentiable with respect to optimization variables, on the basis of the Bregman divergence associated with the primitive function of the clipping function. By using this formulation in combination with the representer theorem, we need only to deal with a finite-dimensional, convex, and differentiable optimization problem, which can be solved by well-established algorithms. We also show two practical examples of inverse problems where our theory can be applied, estimation of band-limited signals and time-harmonic acoustic fields, and evaluate the validity of our theory by numerical simulations.

• Yanjun LI, Haibin KAN, Jie PENG, Chik HOW TAN, Baixiang LIU
原稿種別: LETTER
論文ID: 2021EAL2003
発行日: 2021年
[早期公開] 公開日: 2021/02/22
ジャーナル 認証あり 早期公開

In this letter, we present a construction of bent functions which generalizes a work of Zhang et al. in 2016. Based on that, we obtain a cubic bent function in 10 variables and prove that, it has no affine derivative and does not belong to the completed Maiorana-McFarland class, which is opposite to all 6/8-variable cubic bent functions as they are inside the completed Maiorana-McFarland class. This is the first time a theoretical proof is given to show that the cubic bent functions in 10 variables can be outside the completed Maiorana-McFarland class. Before that, only a sporadic example with such properties was known by computer search. We also show that our function is EA-inequivalent to that sporadic one.

• Fang WANG, Zhe WEI
原稿種別: LETTER
論文ID: 2020EAL2125
発行日: 2021年
[早期公開] 公開日: 2021/02/19
ジャーナル 認証あり 早期公開

The unattended malicious nodes pose great security threats to the integrity of the IoT sensor networks. However, preventions such as cryptography and authentication are difficult to be deployed in resource constrained IoT sensor nodes with low processing capabilities and short power supply. To tackle these malicious sensor nodes, in this study, the trust computing method is applied into the IoT sensor networks as a light weight security mechanism, and based on the theory of Chebyshev Polynomials for the approximation of time series, the trust data sequence generated by each sensor node is linearized and treated as a time series for malicious node detection. The proposed method is evaluated against existing schemes using several simulations and the results demonstrate that our method can better deal with malicious nodes resulting in higher correct packet delivery rate.

• Seiichi KOJIMA, Noriaki SUETAKE
原稿種別: LETTER
論文ID: 2020EAL2120
発行日: 2021年
[早期公開] 公開日: 2021/02/17
ジャーナル 認証あり 早期公開

LIME is a method for low-light image enhancement. Though LIME significantly enhances the contrast in dark regions, the effect of contrast enhancement tends to be insufficient in bright regions. In this letter, we propose an improved method of LIME. In the proposed method, the contrast in bright regions are improved while maintaining the contrast enhancement effect in dark regions.

• Lingjun KONG, Haiyang LIU, Jin TIAN, Shunwai ZHANG, Shengmei ZHAO, Yi ...
原稿種別: LETTER
論文ID: 2020EAL2115
発行日: 2021年
[早期公開] 公開日: 2021/02/16
ジャーナル 認証あり 早期公開

In this letter, a method for the construction of polar codes based on the mutual information approximation (MIA) is proposed for the 4Tb/in2 two-dimensional inter-symbol interference (2D-ISI) channels, such as the bit-patterned magnetic recording (BPMR) and two-dimensional magnetic recording (TDMR). The basic idea is to exploit the MIA between the input and output of a 2D detector to establish a log-likelihood ratio (LLR) distribution model based on the MIA results, which compensates the gap caused by the 2D ISI channel. Consequently, the polar codes obtained by the optimization techniques previously developed for the additive white Gaussian noise (AWGN) channels can also have satisfactory performances over 2D-ISI channels. Simulated results show that the proposed polar codes can outperform the polar codes constructed by the traditional methods over 4Tb/in2 2D-ISI channels.

• Masayoshi NAKAMOTO, Naoyuki AIKAWA
原稿種別: PAPER
論文ID: 2020EAP1096
発行日: 2021年
[早期公開] 公開日: 2021/02/15
ジャーナル 認証あり 早期公開

Recent trends in designing filters involve development of sparse filters with coefficients that not only have real but also zero values. These sparse filters can achieve a high performance through optimizing the selection of the zero coefficients and computing the real (non-zero) coefficients. Designing an infinite impulse response (IIR) sparse filter is more challenging than designing a finite impulse response (FIR) sparse filter. Therefore, studies on the design of IIR sparse filters have been rare. In this study, we consider IIR filters whose coefficients involve zero value, called sparse IIR filter. First, we formulate the design problem as a linear programing problem without imposing any stability condition. Subsequently, we reformulate the design problem by altering the error function and prepare several possible denominator polynomials with stable poles. Finally, by incorporating these methods into successive thinning algorithms, we develop a new design algorithm for the filters. To demonstrate the effectiveness of the proposed method, its performance is compared with that of other existing methods.

• Hironori KIYA, Katsuki OHTO, Hirotaka ONO
原稿種別: PAPER
論文ID: 2020DMP0026
発行日: 2021年
[早期公開] 公開日: 2021/02/10
ジャーナル 認証あり 早期公開

DAIHINMIN, which means Grand Pauper, is a popular playing-card game in Japan. TANHINMIN is a simplified variant of DAIHINMIN, which was proposed by Nishino in 2007 in order to investigate the mathematical properties of DAIHINMIN. In this paper, we consider a 2-player generalized TANHINMIN, where the deck size is arbitrary n. We present a linear-time algorithm that determines which player has a winning strategy after all cards are distributed to the players.

• Seongah JEONG, Jinkyu KANG, Hoojin LEE
原稿種別: LETTER
論文ID: 2020EAL2106
発行日: 2021年
[早期公開] 公開日: 2021/02/08
ジャーナル 認証あり 早期公開

In this letter, we investigate tight analytical and asymptotic upper bounds for bit error rate (BER) of constitutional codes over exponentially correlated Nakagami-m fading channels. Specifically, we derive the BER expression depending on an exact closed-form formula for pairwise error event probabilities (PEEP). Moreover, the corresponding asymptotic analysis in high signal-to-noise ratio (SNR) regime is also explored, which is verified via numerical results. This allows us to have explicit insights on the achievable coding gain and diversity order.

• Masato KIKUCHI, Kento KAWAKAMI, Kazuho WATANABE, Mitsuo YOSHIDA, Kyoji ...
原稿種別: PAPER
論文ID: 2020EAP1088
発行日: 2021年
[早期公開] 公開日: 2021/02/08
ジャーナル 認証あり 早期公開

Likelihood ratios (LRs), which are commonly used for probabilistic data processing, are often estimated based on the frequency counts of individual elements obtained from samples. In natural language processing, an element can be a continuous sequence of N items, called an N-gram, in which each item is a word, letter, etc. In this paper, we attempt to estimate LRs based on N-gram frequency information. A naive estimation approach that uses only N-gram frequencies is sensitive to low-frequency (rare) N-grams and not applicable to zero-frequency (unobserved) N-grams; these are known as the low- and zero-frequency problems, respectively. To address these problems, we propose a method for decomposing N-grams into item units and then applying their frequencies along with the original N-gram frequencies. Our method can obtain the estimates of unobserved N-grams by using the unit frequencies. Although using only unit frequencies ignores dependencies between items, our method takes advantage of the fact that certain items often co-occur in practice and therefore maintains their dependencies by using the relevant N-gram frequencies. We also introduce a regularization to achieve robust estimation for rare N-grams. Our experimental results demonstrate that our method is effective at solving both problems and can effectively control dependencies.

• Ryosuke SUGIURA, Yutaka KAMAMOTO, Takehiro MORIYA
原稿種別: PAPER
論文ID: 2020EAP1099
発行日: 2021年
[早期公開] 公開日: 2021/02/08
ジャーナル 認証あり 早期公開

This paper presents extended-domain Golomb (XDG) code, an extension of Golomb code for sparse geometric sources as well as a generalization of extended-domain Golomb-Rice (XDGR) code, based on the idea of almost instantaneous fixed-to-variable length (AIFV) codes. Showing that the XDGR encoding can be interpreted as extended usage of the code proposed in the previous works, this paper discusses the following two facts: The proposed XDG code can be constructed as an AIFV code relating to Golomb code as XDGR code does to Rice code; XDG and Golomb codes are symmetric in the sense of relative redundancy. The proposed XDG code can be efficiently used for losslessly compressing geometric sources too sparse for the conventional Golomb and Rice codes. According to the symmetry, its relative redundancy is guaranteed to be as low as Golomb code compressing non-sparse geometric sources. Awing to this fact, the parameter of the proposed XDG code, which is more finely tunable than the conventional XDGR code, can be optimized for given inputs using the conventional techniques. Therefore, it is expected to be more useful for many coding applications that deal with geometric sources at low bit rates.

• Yang YAN, Yao YAO, Zhi CHEN, Qiuyan WANG
原稿種別: PAPER
論文ID: 2020EAP1124
発行日: 2021年
[早期公開] 公開日: 2021/02/08
ジャーナル 認証あり 早期公開

Codebooks with small inner-product correlation have applied in direct spread code division multiple access communications, space-time codes and compressed sensing. In general, it is difficult to construct optimal codebooks achieving the Welch bound or the Levenstein bound. This paper focuses on constructing asymptotically optimal codebooks with characters of cyclic groups. Based on the proposed constructions, two classes of asymptotically optimal codebooks with respect to the Welch bound are presented. In addition, parameters of these codebooks are new.

• Makoto YAMASHITA, Naoki HAYASHI, Takeshi HATANAKA, Shigemasa TAKAI
原稿種別: PAPER
論文ID: 2020EAP1111
発行日: 2021年
[早期公開] 公開日: 2021/02/04
ジャーナル 認証あり 早期公開

This paper investigates a constrained distributed online optimization problem over strongly connected communication networks, where a local cost function of each agent varies in time due to environmental factors. We propose a distributed online projected subgradient method over unbalanced directed networks. The performance of the proposed method is evaluated by a regret which is defined by the error between the cumulative cost over time and the cost of the optimal strategy in hindsight. We show that a logarithmic regret bound can be achieved for strongly convex cost functions. We also demonstrate the validity of the proposed method through a numerical example on distributed estimation over a diffusion field.

• Dang THANH VU, Vo HOANG TRONG, Yu GWANG HYUN, Kim JIN YOUNG
原稿種別: PAPER
論文ID: 2020EAP1101
発行日: 2021年
[早期公開] 公開日: 2021/01/27
ジャーナル 認証あり 早期公開

Capsules are fundamental informative units that are introduced into capsule networks to manipulate the hierarchical presentation of patterns. The part–whole relationship of an entity is learned through capsule layers, using a routing-by-agreement mechanism that is approximated by a voting procedure. Nevertheless, existing routing methods are computationally inefficient. We address this issue by proposing a novel routing mechanism, namely "shortcut routing", that directly learns to activate global capsules from local capsules. In our method, the number of operations in the routing procedure is reduced by omitting the capsules in intermediate layers, resulting in lighter routing. To further address the computational problem, we investigate an attention-based approach, and propose fuzzy coefficients, which have been found to be efficient than mixture coefficients from EM routing. Our method achieves on-par classification results on the Mnist (99.52%), smallnorb (93.91%), and affNist (89.02%) datasets. Compared to EM routing, our fuzzy-based and attention-based routing methods attain reductions of 142 and 25 in terms of the number of calculations.

• Kenji Uehara, Kunihiko Hiraishi, Kokolo Ikeda
原稿種別: PAPER
論文ID: 2020EAP1077
発行日: 2021年
[早期公開] 公開日: 2021/01/22
ジャーナル 認証あり 早期公開

Boarding is the last step of aircraft turnaround and its completion in the shortest possible time is desired. In this paper, we propose a new boarding strategy that outperforms conventional strategies such as the back-to-front strategy and the outside-in strategy. The Steffen method is known as one of the most efficient boarding strategies in literature, but it is hard to be realized in the real situation because the complete sorting of passengers in a prescribed order is required. The proposed strategy shows a performance close to that of the Steffen method and can be easily implemented by using a special gate system.

• Minako Kamiyama, Akira Taguchi
原稿種別: LETTER
論文ID: 2020EAL2087
発行日: 2021年
[早期公開] 公開日: 2021/01/18
ジャーナル 認証あり 早期公開

In color image processing, preservation of hue is required. Therefore, perceptual color models such as HSI and HSV have been used. Hue-Saturation-Intensity (HSI) is a public color model, and many color applications have been made based on this model. However, the transformation from the conventional HSI (C-HSI) color space to the RGB color space after processing intensity/saturation in the C-HSI color space often generates the gamut problem, because the shape of C-HSI color space is a triangular pyramid which includes the RGB color space. When the output of intensity/saturation processing result is located in the outside of the common region of RGB color space and C-HSI color space, it is necessary to move to the RGB color space. The effective way of hue and intensity preserving saturation correction algorithm is proposed. According to the proposed saturation correction algorithm, the corrected saturation value is same as the processing result in the ideal HSI color space whose gamut same as the RGB gamut.

• Pan TAN, Zhengchun ZHOU, Haode YAN, Yong WANG
原稿種別: LETTER
論文ID: 2020EAL2100
発行日: 2021年
[早期公開] 公開日: 2021/01/18
ジャーナル 認証あり 早期公開

Locally repairable codes (LRCs) with availability have received considerable attention in recent years since they are able to solve many problems in distributed storage systems such as repairing multiple node failures and managing hot data. Constructing LRCs with locality r and availability t (also called (r, t)-LRCs) with new parameters becomes an interesting research subject in coding theory. The objective of this paper is to propose two generic constructions of cyclic (r, t)-LRCs via linearized polynomials over finite fields. These two constructions include two earlier ones of cyclic LRCs from trace functions and truncated trace functions as special cases and lead to LRCs with new parameters that can not be produced by earlier ones.

• Lei YANG, Tingxiao YANG, Hiroki KIMURA, Yuichiro YOSHIMURA, Kumiko ARA ...
原稿種別: PAPER
論文ID: 2020IMP0014
発行日: 2021年
[早期公開] 公開日: 2021/01/18
ジャーナル 認証あり 早期公開

In medical fields, detecting traumatic bleedings has always been a difficult task due to the small size, low contrast of targets and large number of images. In this work we propose an automatic traumatic bleeding detection approach from contrast enhanced CT images via deep CNN networks, containing segmentation process and classification process. CT values of DICOM images are extracted and processed via three different window settings first. Small 3D patches are cropped from processed images and segmented by a 3D CNN network. Then segmentation results are converted to point cloud data format and classified by a classifier. The proposed pre-processing approach makes the segmentation network be able to detect small and low contrast targets and achieve a high sensitivity. The additional classification network solves the boundary problem and short-sighted problem generated during the segmentation process to further decrease false positives. The proposed approach is tested with 3 CT cases containing 37 bleeding regions. As a result, a total of 34 bleeding regions are correctly detected, the sensitivity reaches 91.89%. The average false positive number of test cases is 1678. 46.1% of false positive predictions are decreased after being classified. The proposed method is proved to be able to achieve a high sensitivity and be a reference of medical doctors.

• Yuelei XIAO, Shuang HUANG
原稿種別: LETTER
論文ID: 2020EAL2084
発行日: 2021年
[早期公開] 公開日: 2021/01/12
ジャーナル 認証あり 早期公開

For the first stage of the multi-sensitive bucketization (MSB) method, the l-diversity grouping for multiple sensitive attributes is incomplete, causing more information loss. To solve this problem, we give the definitions of the l-diversity avoidance set for multiple sensitive attributes and the avoiding of a multiple dimensional bucket, and propose a complete l-diversity grouping (CLDG) algorithm for multiple sensitive attributes. Then, we improve the first stages of the MSB algorithms by applying the CLDG algorithm to them. The experimental results show that the grouping ratio of the improved first stages of the MSB algorithms is significantly higher than that of the original first stages of the MSB algorithms, decreasing the information loss of the published microdata.

• Hong-Li WANG, Li-Li FAN, Gang WANG, Lin-Zhi SHEN
原稿種別: LETTER
論文ID: 2020EAL2113
発行日: 2021年
[早期公開] 公開日: 2021/01/12
ジャーナル 認証あり 早期公開

In the letter, two classes of optimal codebooks and asymptotically optimal codebooks in regard to the Levenshtein bound are presented, which are based on mutually unbiased bases (MUB) and approximately mutually unbiased bases (AMUB), respectively.

• Nuttapong ATTRAPADUNG, Goichiro HANAOKA, Takato HIRANO, Yutaka KAWAI, ...
原稿種別: PAPER
論文ID: 2020EAP1074
発行日: 2021年
[早期公開] 公開日: 2021/01/12
ジャーナル 認証あり 早期公開

In this paper, we put forward the notion of a token-based multi-input functional encryption (token-based MIFE) scheme — a notion intended to give encryptors a mechanism to control the decryption of encrypted messages, by extending the encryption and decryption algorithms to additionally use tokens. The basic idea is that a decryptor must hold an appropriate decryption token in addition to his secrete key, to be able to decrypt. This type of scheme can address security concerns potentially arising in applications of functional encryption aimed at addressing the problem of privacy preserving data analysis. We firstly formalize token-based MIFE, and then provide two basic schemes; both are based on an ordinary MIFE scheme, but the first additionally makes use of a public key encryption scheme, whereas the second makes use of a pseudorandom function (PRF). Lastly, we extend the latter construction to allow decryption tokens to be restricted to specified set of encryptions, even if all encryptions have been done using the same encryption token. This is achieved by using a constrained PRF.

• Rui LI, Ruqi XIAO, Hong GU, Weimin SU
原稿種別: PAPER
論文ID: 2020EAP1098
発行日: 2021年
[早期公開] 公開日: 2021/01/07
ジャーナル 認証あり 早期公開

A novel direction of arrival (DOA) estimation method for the coherent signal is presented in this paper. The proposed method applies the eigenvector associated with max eigenvalue, which contains the DOAs of all signals, to form a Toeplitz matrix, yielding an unconstrained optimization problem. Then, the DOA is obtained by peak searching of the pseudo power spectrum without the knowledge of signal number. It is illustrated that the method has a great performance and low computation complexity for the coherent signal. Simulation results verify the usefulness of the method.

• Misaki SHIKAKURA, Yusuke KAMEDA, Takayuki HAMAMOTO
原稿種別: LETTER
論文ID: 2020IML0007
発行日: 2021年
[早期公開] 公開日: 2021/01/07
ジャーナル 認証あり 早期公開

This paper reports the evolution and application potential of image sensors with high-speed brightness gradient sensors. We propose an adaptive exposure time control method using the apparent motion estimated by this sensor, and evaluate results for the change in illuminance and global / local motion.

• Shiori YAMAGUCHI, Keita HIRAI, Takahiko HORIUCHI
原稿種別: PAPER
論文ID: 2020IMP0013
発行日: 2021年
[早期公開] 公開日: 2021/01/07
ジャーナル 認証あり 早期公開

In this study, we present a novel method for removing smoke from videos based on a single image sequence. Smoke is a significant artifact in images or videos because it can reduce the visibility in disaster scenes. Our proposed method for removing smoke involves two main processes: (1) the development of a smoke imaging model and (2) smoke removal using spatio-temporal pixel compensation. First, we model the optical phenomena in natural scenes including smoke, which is called a smoke imaging model. Our smoke imaging model is developed by extending conventional haze imaging models. We then remove the smoke from a video in a frame-by-frame manner based on the smoke imaging model. Next, we refine the appearance of the smoke-free video by spatio-temporal pixel compensation, where we align the smoke-free frames using the corresponding pixels. To obtain the corresponding pixels, we use SIFT and color features with distance constraints. Finally, in order to obtain a clear video, we refine the pixel values based on the spatio-temporal weightings of the corresponding pixels in the smoke-free frames. We used simulated and actual smoke videos in our validation experiments. The experimental results demonstrated that our method can obtain effective smoke removal results from dynamic scenes. We also quantitatively assessed our method based on a temporal coherence measure.

• Keisuke OKANO, Naoto SASAOKA, Yoshio ITOH
原稿種別: PAPER
論文ID: 2020EAP1081
発行日: 2020年
[早期公開] 公開日: 2020/12/28
ジャーナル 認証あり 早期公開

We propose online feedback path modeling with a pre-inverse type active noise control (PIANC) system to track the fluctuation stably in the feedback path. The conventional active noise control (ANC) system with online feedback path modeling (FBPM) filter bases filtered-x least mean square (FxLMS) algorithm. In the FxLMS algorithm, the error of FBPM influences a control filter, which generates an anti-noise, and secondary path modeling (SPM) filter. The control filter diverges when the error is too large. Therefore, it is difficult for the FxLMS algorithm to track the feedback path without divergence. On the other hand, the proposed approach converges stably because the FBPM filter's error does not influence a control filter on the PIANC system. Thus, the proposed method can reduce noise while tracking the feedback path. This paper verified the effectiveness of the proposed method by convergence analysis, computer simulation, and implementation of a digital signal processor.

• Lin YAN, Mingyong ZENG, Shuai REN, Zhangkai LUO
原稿種別: LETTER
論文ID: 2020EAL2102
発行日: 2020年
[早期公開] 公開日: 2020/12/24
ジャーナル 認証あり 早期公開

Traffic categorization aims to classify network traffic into major service types. A modern deep neural network based on temporal sequence modeling is proposed for encrypted traffic categorization. The contemporary techniques such as dilated convolution and residual connection are adopted as the basic building block. The raw traffic files are pre-processed to generate 1-dimensional ow byte sequences and are feed into our specially-devised network. The proposed approach outperforms other existing methods greatly on a public traffic dataset.

• Miho SHINOHARA, Yukina TAMURA, Shinya MOCHIDUKI, Hiroaki KUDO, Mitsuho ...
原稿種別: LETTER
論文ID: 2020IML0001
発行日: 2020年
[早期公開] 公開日: 2020/12/15
ジャーナル 認証あり 早期公開

We investigated the function in the Lateral Geniculate Nucleus of avoidance behavior due to the inconsistency between binocular retinal images due to blue from vergence eye movement based on avoidance behavior caused by the inconsistency of binocular retinal images when watching the rim of a blue-yellow equiluminance column.

• Miho SHINOHARA, Reiko KOYAMA, Shinya MOCHIDUKI, Mitsuho YAMADA
原稿種別: LETTER
論文ID: 2020IML0002
発行日: 2020年
[早期公開] 公開日: 2020/12/15
ジャーナル 認証あり 早期公開

We paid attention the amount of change for each resolution by specifying the gaze position of images, and measured accommodation and convergence eye movement when watching high-resolution images. Change of convergence angle and accommodation were like the actual depth composition in the image when images were presented in the high-resolution.

• Kwangjin JEONG, Masahiro YUKAWA
原稿種別: PAPER
論文ID: 2020EAP1080
発行日: 2020年
[早期公開] 公開日: 2020/12/11
ジャーナル 認証あり 早期公開

Multikernel adaptive filtering is an attractive nonlinear approach to online estimation/tracking tasks. Despite its potential advantages over its single-kernel counterpart, a use of inappropriately weighted kernels may result in a negligible performance gain. In this paper, we propose an efficient recursive kernel weighting technique for multikernel adaptive filtering to activate all the kernels. The proposed weights equalize the convergence rates of all the corresponding partial coefficient errors. The proposed weights are implemented via a certain metric design based on the weighting matrix. Numerical examples show, for synthetic and multiple real datasets, that the proposed technique exhibits a better performance than the manually-tuned kernel weights, and that it significantly outperforms the online multiple kernel regression algorithm.

• Hiroaki KUDO, Tetsuya MATSUMOTO, Kentaro KUTSUKAKE, Noritaka USAMI
原稿種別: PAPER
論文ID: 2020IMP0010
発行日: 2020年
[早期公開] 公開日: 2020/12/08
ジャーナル 認証あり 早期公開

In this paper, we evaluate a prediction method of regions including dislocation clusters which are crystallographic defects in a photoluminescence (PL) image of multicrystalline silicon wafers. We applied a method of a transfer learning of the convolutional neural network to solve this task. For an input of a sub-region image of a whole PL image, the network outputs the dislocation cluster regions are included in the upper wafer image or not. A network learned using image in lower wafers of the bottom of dislocation clusters as positive examples. We experimented under three conditions as negative examples; image of some depth wafer, randomly selected images, and both images. We examined performances of accuracies and Youden's J statistics under 2 cases; predictions of occurrences of dislocation clusters at 10 upper wafer or 20 upper wafer. Results present that values of accuracies and values of Youden's J are not so high, but they are higher results than ones of bag of features (visual words) method. For our purpose to find occurrences dislocation clusters in upper wafers from the input wafer, we obtained results that randomly select condition as negative examples is appropriate for 10 upper wafers prediction, since its results are better than other negative examples conditions, consistently.

• Kensho HARA
原稿種別: PAPER
論文ID: 2020IMP0012
発行日: 2020年
[早期公開] 公開日: 2020/12/07
ジャーナル 認証あり 早期公開

The performance of video action recognition has improved significantly in recent decades. Current recognition approaches mainly utilize convolutional neural networks to acquire video feature representations. In addition to the spatial information of video frames, temporal information such as motions and changes is important for recognizing videos. Therefore, the use of convolutions in a spatiotemporal three-dimensional (3D) space for representing spatiotemporal features has garnered significant attention. Herein, we introduce recent advances in 3D convolutions for video action recognition.

• Zhen Li, Baojun Zhao, Wenzheng Wang, Baoxian Wang
原稿種別: LETTER
論文ID: 2020EAL2099
発行日: 2020年
[早期公開] 公開日: 2020/12/01
ジャーナル 認証あり 早期公開

Hyperspectral images (HSIs) are generally susceptible to various noise, such as Gaussian and stripe noise. Recently, numerous denoising algorithms have been proposed to recover the HSIs. However, those approaches cannot use spectral information efficiently and suffer from the weakness of stripe noise removal. Here, we propose a tensor decomposition method with two different constraints to remove the mixed noise from HSIs. For a HSI cube, we first employ the tensor singular value decomposition (t-SVD) to effectively preserve the low-rank information of HSIs. Considering the continuity property of HSIs spectra, we design a simple smoothness constraint by using Tikhonov regularization for tensor decomposition to enhance the denoising performance. Moreover, we also design a new unidirectional total variation (TV) constraint to filter the stripe noise from HSIs. This strategy will achieve better performance for preserving images details than original TV models. The developed method is evaluated on both synthetic and real noisy HSIs, and shows the favorable results.

• Kazuhiro SATO, Shun-ichi AZUMA
原稿種別: PAPER
論文ID: 2020EAP1093
発行日: 2020年
[早期公開] 公開日: 2020/12/01
ジャーナル 認証あり 早期公開

We address analysis and design problems of aggregate demand response systems composed of various consumers based on controllability to facilitate to design automated demand response machines that are installed into consumers to automatically respond to electricity price changes. To this end, we introduce a controllability index that expresses the worst-case error between the expected total electricity consumption and the electricity supply when the best electricity price is chosen. The analysis problem using the index considers how to maximize the controllability of the whole consumer group when the consumption characteristic of each consumer is not fixed. In contrast, the design problem considers the whole consumer group when the consumption characteristics of a part of the group are fixed. By solving the analysis problem, we first clarify how the controllability, average consumption characteristics of all consumers, and the number of selectable electricity prices are related. In particular, the minimum value of the controllability index is determined by the number of selectable electricity prices. Next, we prove that the design problem can be solved by a simple linear optimization. Numerical experiments demonstrate that our results are able to increase the controllability of the overall consumer group.

• Rintaro YANAGI, Ren TOGO, Takahiro OGAWA, Miki HASEYAMA
原稿種別: PAPER
論文ID: 2020IMP0011
発行日: 2020年
[早期公開] 公開日: 2020/11/30
ジャーナル 認証あり 早期公開

Various cross-modal retrieval methods that can retrieve images related to a query sentence without text annotations have been proposed. Although a high level of retrieval performance is achieved by these methods, they have been developed for a single domain retrieval setting. When retrieval candidate images come from various domains, the retrieval performance of these methods might be decreased. To deal with this problem, we propose a new domain adaptive cross-modal retrieval method. By translating a modality and domains of a query and candidate images, our method can retrieve desired images accurately in a different domain retrieval setting. Experimental results for clipart and painting datasets showed that the proposed method has better retrieval performance than that of other conventional and state-of-the-art methods.

• Kazuki Matsuyama, Toru Tanzawa
原稿種別: PAPER
論文ID: 2020EAP1083
発行日: 2020年
[早期公開] 公開日: 2020/11/24
ジャーナル 認証あり 早期公開

This paper formulates minimal word-line (WL) delay time with pre-emphasis pulses to design the pulse width as a function of the overdrive voltage for large memory arrays such as 3D NAND. Circuit theory for a single RC line only with capacitance to ground and that only with coupling capacitance as well as a general case where RC lines have both grounded and coupling capacitance is discussed to provide an optimum pre-emphasis pulse width to minimize the delay time. The theory is expanded to include the cases where the resistance of the RC line driver is not negligibly small. The minimum delay time formulas of a single RC delay line and capacitive coupling RC lines was in good agreement (i.e. within 5% error) with measurement. With this research, circuit designers can estimate an optimum pre-emphasis pulse width and the delay time for an RC line in the initial design phase.

• Changyong SHIN, Jiho HAN
原稿種別: LETTER
論文ID: 2020EAL2092
発行日: 2020年
[早期公開] 公開日: 2020/11/16
ジャーナル 認証あり 早期公開

This letter proposes a downlink multiple-input multiple-output (MIMO) non-orthogonal multiple access technique that mitigates multi-cell interference (MCI) at cell-edge users, regardless of the number of interfering cells, thereby improving the spectral efficiency. This technique employs specific receive beamforming vectors at the cell-edge users in clusters to minimize the MCI. Based on the receive beamforming vectors adopted by the cell-edge users, the transmit beamforming vectors for a base station (BS) and the receive beamforming vectors for cell-center users are designed to eliminate the inter-cluster interference and maximize the spectral efficiency. As each user can directly obtain its own receive beamforming vector, this technique does not require channel feedback from the users to a BS to design the receive beamforming vectors, thereby reducing the system overhead. We also derive the upper bound of the average sum rate achievable using the proposed technique. Finally, we demonstrate through simulations that the proposed technique achieves a better sum rate performance than the existing schemes and that the derived upper bound is valid.

• Jianli CAO, Zhikui CHEN, Yuxin WANG, He GUO, Pengcheng WANG
原稿種別: PAPER
論文ID: 2020EAP1105
発行日: 2020年
[早期公開] 公開日: 2020/11/16
ジャーナル 認証あり 早期公開

Like many processors, GPGPU suffers from memory wall. The traditional solution for this issue is to use efficient schedulers to hide long memory access latency or use data prefetch mech-anism to reduce the latency caused by data transfer. In this paper, we study the instruction fetch stage of GPU's pipeline and analyze the relationship between the capacity of GPU kernel and instruction miss rate. We improve the next line prefetch mechanism to fit the SIMT model of GPU and determine the optimal parameters of prefetch mechanism on GPU through experiments. The experimental result shows that the prefetch mechanism can achieve 12.17% performance improvement on average. Compared with the solution of enlarging I-Cache, prefetch mechanism has the advantages of more beneficiaries and lower cost.

• Ce SHI, Jianfeng FU, Chengmin WANG, Jie YAN
原稿種別: LETTER
論文ID: 2020EAL2081
発行日: 2020年
[早期公開] 公開日: 2020/11/13
ジャーナル 認証あり 早期公開

The use of locating arrays is motivated by the use of generating software test suites to locate interaction faults in component-based systems. In this paper, we introduce a new combinatorial configuration, with which a general combinatorial description of $(\bar{1},t)$-locating arrays is presented. Based on this characterization, a number of locating arrays by means of SSOA and difference covering arrays with prescribed properties are constructed effectively. As a consequence, upper bounds on the size of locating arrays with small number of factors are then obtained.

• Xiaoping Zhou, Bin Wu, Kan Zheng, Hui Zhao
原稿種別: LETTER
論文ID: 2020EAL2038
発行日: 2020年
[早期公開] 公開日: 2020/11/12
ジャーナル 認証あり 早期公開

In this letter, an angle adjustment method is proposed to improve the accuracy of the sampling frequency offset (SFO) estimation for the very high throughput wireless local area networks (WLANs). This angle adjustment can work together with existing least square (LS) and weighted least square (WLS) to achieve better system performance. Simulation results show that, the angle adjustment can help LS and WLS to get better pocket error rate (PER).

• Guangmiao ZENG, Rongjie WANG, Ran HAN
原稿種別: PAPER
論文ID: 2020EAP1035
発行日: 2020年
[早期公開] 公開日: 2020/11/11
ジャーナル 認証あり 早期公開

Because solar energy is intermittent and a ship's power-system load fluctuates and changes abruptly, in this work, the solar radiation parameters were adjusted according to the latitude and longitude of the ship and the change of the sea environment. An objective function was constructed that accounted for the cost and service life simultaneously to optimize the configuration of the marine diesel engine hybrid energy system. Finally, the improved artificial bee colony algorithm was used to optimize and obtain the optimal system configuration. The feasibility of the method was verified by ship navigation tests. This method exhibited better configuration performance optimization than the traditional methods.

• Wentao FENG, Dexiu HU
原稿種別: LETTER
論文ID: 2020EAL2096
発行日: 2020年
[早期公開] 公開日: 2020/11/09
ジャーナル 認証あり 早期公開

A modified whale optimization algorithm (MWOA) with dynamic leader selection mechanism and novel population updating procedure is introduced for pattern synthesis of linear antenna array. The current best solution is dynamic changed for each whale agent to overcome premature with local optima in iteration. A hybrid crossover operator is embedded in original algorithm to improve the convergence accuracy of solution. Moreover, the flow of population updating is optimized to balance the exploitation and exploration ability. The modified algorithm is tested on a 28 elements uniform linear antenna array to reduce its side lobe lever and null depth lever. The simulation results show that MWOA algorithm can improve the performance of WOA obviously compared with other algorithms.

原稿種別: PAPER
論文ID: 2020EAP1014
発行日: 2020年
[早期公開] 公開日: 2020/11/09
ジャーナル 認証あり 早期公開

In order to erase data including confidential information stored in storage devices, an unrelated and random sequence is usually overwritten, which prevents the data from being restored. The problem of minimizing the cost for information erasure when the amount of information leakage of the confidential information should be less than or equal to a constant asymptotically has been introduced by T. Matsuta and T. Uyematsu. Whereas the minimum cost for overwriting has been given for general sources, a single-letter characterization for stationary memoryless sources is not easily derived. In this paper, we give single-letter characterizations for stationary memoryless sources under two types of restrictions: one requires the output distribution of the encoder to be independent and identically distributed (i.i.d.) and the other requires it to be memoryless but not necessarily i.i.d. asymptotically. The characterizations indicate the relation among the amount of information leakage, the minimum cost for information erasure and the rate of the size of uniformly distributed sequences. The obtained results show that the minimum costs are different between these restrictions.

• Lu Sun, Bin Wu, Tianchun Ye
原稿種別: LETTER
論文ID: 2020EAL2090
発行日: 2020年
[早期公開] 公開日: 2020/11/02
ジャーナル 認証あり 早期公開

In this letter, a two-stage QR decomposition scheme based on Givens rotation with novel modified real-value decomposition (RVD) is presented. With the modified RVD applied to the result from complex Givens rotation at first stage, the number of non-zero terms needed to be eliminated by real Givens rotation at second stage decreases greatly and the computational complexity is thereby reduced significantly compared to the decomposition scheme with the conventional RVD. Besides, the proposed scheme is suitable for the hardware design of QR decomposition. Evaluation shows that the proposed QR decomposition scheme is superior to the related works in terms of computational complexity.

• Shuhei OTA, Mitsuhiro KIMURA
原稿種別: LETTER
論文ID: 2020EAL2080
発行日: 2020年
[早期公開] 公開日: 2020/10/27
ジャーナル 認証あり 早期公開

An n-variate Farlie-Gumbel-Morgenstern (FGM) copula consists of 2n - n - 1 parameters that express multivariate dependence among random variables. Motivated by the dependence structure of the n-variate FGM copula, we derive the exact range of the n-variate FGM copula's parameter. The exact range of the parameter is given by a closedform expression under the condition that all parameters take the same value. Moreover, under the same condition, we reveal that the n-variate FGM copula becomes the independence copula for n → ∞. This result contributes to the dependence modeling such as reliability analysis considering dependent failure occurrence.

• Yoshihiro MURASHIMA, Taishin NAKAMURA, Hisashi YAMAMOTO, Xiao XIAO
原稿種別: PAPER
論文ID: 2020EAP1066
発行日: 2020年
[早期公開] 公開日: 2020/10/27
ジャーナル 認証あり 早期公開

In a network topology design problem, it is important to analyze the reliability and construction cost of complex network systems. This paper addresses a topological optimization problem of minimizing the total cost of a network system with separate subsystems under a reliability constraint. To solve this problem, we develop three algorithms. The first algorithm finds an exact solution. The second one finds an exact solution, specialized for a system with identical subsystems. The third one is a heuristic algorithm, which finds an approximate solution when a network system has several identical subsystems. We also conduct numerical experiments and demonstrate the efficacy and efficiency of the developed algorithms.

• Zedong SUN, Chunxiang GU, Yonghui ZHENG
原稿種別: PAPER
論文ID: 2020EAP1064
発行日: 2020年
[早期公開] 公開日: 2020/10/22
ジャーナル 認証あり 早期公開

Sieve algorithms are regarded as the best algorithms to solve the shortest vector problem (SVP) on account of its good asymptotical quality, which could make it outperform enumeration algorithms in solving SVP of high dimension. However, due to its large memory requirement, sieve algorithms are not practical as expected, especially on high dimension lattice. To overcome this bottleneck, TupleSieve algorithm was proposed to reduce memory consumption by a trade-off between time and memory.

In this work, aiming to make TupleSieve algorithm more practical, we combine TupleSieve algorithm with SubSieve technique and obtain a sub-exponential gain in running time. For 2-tuple sieve, 3-tuple sieve and arbitrary k-tuple sieve, when selecting projection index d appropriately, the time complexity of our algorithm is O(20.415(n-d)), O(20.566(n-d)) and $O(2^{\frac{k\mathrm{log}_2p}{1-k}(n-d)})$ respectively. In practice, we propose a practical variant of our algorithm based on GaussSieve algorithm. Experimental results show that our algorithm implementation is about two order of magnitude faster than FPLLL's GuassSieve algorithm. Moreover, techniques such as XOR-POPCNT trick, progressive sieving and appropriate projection index selection can be exploited to obtain a further acceleration.

• Di YAO, Aijun LIU, Hongzhi LI, Changjun YU
原稿種別: LETTER
論文ID: 2020EAL2093
発行日: 2020年
[早期公開] 公開日: 2020/10/15
ジャーナル 認証あり 早期公開

In the user-congested high-frequency band, radio frequency interference (RFI) is a dominant factor that degrades the detection performance of high-frequency surface wave radar (HFSWR). Up to now, various RFI suppression algorithms have been proposed while they are usually inapplicable to the compact HFSWR because of the minimal array aperture. Therefore, this letter proposes a novel RFI mitigation scheme for compact HFSWR, even for single antenna. The scheme utilized the robust principal component analysis to separate RFI and target, based on the time-frequency distribution characteristics of the RFI. The effectiveness of this scheme is demonstrated by the measured data, which can effectively suppress RFI without losing target signal.

• Riku AKEMA, Masao YAMAGISHI, Isao YAMADA
原稿種別: PAPER
論文ID: 2020EAP1062
発行日: 2020年
[早期公開] 公開日: 2020/10/15
ジャーナル 認証あり 早期公開

Approximate Simultaneous Diagonalization (ASD) is a problem to find a common similarity transformation which approximately diagonalizes a given square-matrix tuple. Many data science problems have been reduced into ASD through ingenious modelling. For ASD, the so-called Jacobi-like methods have been extensively used. However, the methods have no guarantee to suppress the magnitude of off-diagonal entries of the transformed tuple even if the given tuple has a common exact diagonalizer, i.e., the given tuple is simultaneously diagonalizable. In this paper, to establish an alternative powerful strategy for ASD, we present a novel two-step strategy, called Approximate-Then-Diagonalize-Simultaneously (ATDS) algorithm. The ATDS algorithm decomposes ASD into (Step 1) finding a simultaneously diagonalizable tuple near the given one; and (Step 2) finding a common similarity transformation which diagonalizes exactly the tuple obtained in Step 1. The proposed approach to Step 1 is realized by solving a Structured Low-Rank Approximation (SLRA) with Cadzow's algorithm. In Step 2, by exploiting the idea in the constructive proof regarding the conditions for the exact simultaneous diagonalizability, we obtain a common exact diagonalizer of the obtained tuple in Step 1 as a solution for the original ASD. Unlike the Jacobi-like methods, the ATDS algorithm has a guarantee to find a common exact diagonalizer if the given tuple happens to be simultaneously diagonalizable. Numerical experiments show that the ATDS algorithm achieves better performance than the Jacobi-like methods.

• Lu Sun, Bin Wu, Tianchun Ye
原稿種別: LETTER
論文ID: 2020EAL2076
発行日: 2020年
[早期公開] 公開日: 2020/10/12
ジャーナル 認証あり 早期公開

In this letter, a low latency, high throughput and hardware efficient sorted MMSE QR decomposition (MMSE-SQRD) for multiple-input multiple-output (MIMO) systems is presented. In contrast to the method of extending the complex matrix to real model and thereafter applying real-valued QR decomposition (QRD), we develop a highly parallel decomposition scheme based on coordinate rotation digital computer (CORDIC) which performs the QRD in complex domain directly and then converting the complex result to its real counterpart. The proposed scheme can greatly improve the processing parallelism and curtail the nullification and sorting procedures. Besides, we also design the corresponding pipelined hardware architecture of the MMSE-SQRD based on highly parallel Givens rotation structure with CORDIC algorithm for 4×4 MIMO detectors. The proposed MMSE-SQRD is implemented in SMIC 55nm CMOS technology achieving up to 50M QRD/s throughput and a latency of 59 clock cycles with only 218 kilo-gates (KG). Compared to the previous works, the proposed design achieves the highest normalized throughput efficiency and lowest processing latency.

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