著者

Keika MORI Takuya WATANABE Yunao ZHOU Ayako AKIYAMA HASEGAWA Mitsuaki AKIYAMA Tatsuya MORI

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Information and Systems (ISSN:09168532)

巻号頁・発行日

vol.E103.D, no.7, pp.1541-1555, 2020-07-01 (Released:2020-07-01)

参考文献数

33

被引用文献数

1 2

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This work aims to determine the propensity of password creation through the lens of language spheres. To this end, we consider four different countries, each with a different culture/language: China/Chinese, United Kingdom (UK) and India/English, and Japan/Japanese. We first employ a user study to verify whether language and culture are reflected in password creation. We found that users in India, Japan, and the UK prefer to create their passwords from base words, and the kinds of words they are incorporated into passwords vary between countries. We then test whether the findings obtained through the user study are reflected in a corpus of leaked passwords. We found that users in China and Japan prefer dates, while users in India, Japan, and the UK prefer names. We also found that cultural words (e.g., “sakura” in Japan and “football” in the UK) are frequently used to create passwords. Finally, we demonstrate that the knowledge on the linguistic background of targeted users can be exploited to increase the speed of the password guessing process.

著者

上坂 晃一 高橋 応明

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

電子情報通信学会論文誌 B (ISSN:13444697)

巻号頁・発行日

vol.J89-B, no.9, pp.1548-1557, 2006-09-01

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近年の非接触ICカード/RFIDタグ等の急速な普及には目覚ましいものがあるが,使用されているアンテナは,システム全体の中で最も設計が難しいといっても過言ではない.これはアンテナの設計パラメータが,形状,材質,ICとのインピーダンス整合,通信エリアや各種規制等の遵守等々と非常に多岐にわたるためである.まず,このRFIDシステムには使用する周波数帯がいくつか用意されている.この中で13.56 MHz帯を用いるシステムでは,アンテナが波長に対して非常に小形となることから微小アンテナの設計技術を必要とする.またUHF帯(860~960 MHz)やISM帯(2.45 GHz帯)等では13.56 MHz帯の場合とは異なり,通信エリアが電磁界の近傍界から遠方界にまで及ぶことから,その全域で動作させる必要があり,設計が困難となる.更に,RFIDを貼り付ける物質(金属や高誘電体等)によっても,アンテナ特性が大きく変化する.本論文では,これらの事例について,無線ICタグの設計法を述べる.

著者

Tatsuya MORI Tetsuya TAKINE Jianping PAN Ryoichi KAWAHARA Masato UCHIDA Shigeki GOTO

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Communications (ISSN:09168516)

巻号頁・発行日

vol.E90-B, no.11, pp.3061-3072, 2007-11-01

被引用文献数

30

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With the rapid increase of link speed in recent years, packet sampling has become a very attractive and scalable means in collecting flow statistics; however, it also makes inferring original flow characteristics much more difficult. In this paper, we develop techniques and schemes to identify flows with a very large number of packets (also known as heavy-hitter flows) from sampled flow statistics. Our approach follows a two-stage strategy: We first parametrically estimate the original flow length distribution from sampled flows. We then identify heavy-hitter flows with Bayes' theorem, where the flow length distribution estimated at the first stage is used as an a priori distribution. Our approach is validated and evaluated with publicly available packet traces. We show that our approach provides a very flexible framework in striking an appropriate balance between false positives and false negatives when sampling frequency is given.

著者

安藤 慎吾 中島 真人

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

電子情報通信学会論文誌 D (ISSN:09151923)

巻号頁・発行日

vol.J84-D2, no.7, pp.1339-1350, 2001-07-01

著者

Seok-Oh YUN Jung Hoon LEE Jin LEE Choul-Young KIM

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Information and Systems (ISSN:09168532)

巻号頁・発行日

vol.E102.D, no.5, pp.1115-1118, 2019-05-01 (Released:2019-05-01)

参考文献数

12

被引用文献数

1 8

---

Real-time monitoring of heart rate (HR) and body temperature (BT) is crucial for the prognosis and the diagnosis of cardiovascular disease and healthcare. Since current monitoring systems are too rigid and bulky, it is not easy to attach them to the human body. Also, their large current consumption limits the working time. In this paper, we develop a wireless sensor patch for HR and BT by integrating sensor chip, wireless communication chip, and electrodes on the flexible boards that is covered with non-toxic, but skin-friendly adhesive patch. Our experimental results reveal that the flexible wireless sensor patch can efficiently detect early diseases by monitoring the HR and BT in real time.

著者

Koichiro YAMANAKA Keita TAKAHASHI Toshiaki FUJII Ryuraroh MATSUMOTO

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Information and Systems (ISSN:09168532)

巻号頁・発行日

vol.E104.D, no.5, pp.785-788, 2021-05-01 (Released:2021-05-01)

参考文献数

15

被引用文献数

4

---

Thanks to the excellent learning capability of deep convolutional neural networks (CNNs), CNN-based methods have achieved great success in computer vision and image recognition tasks. However, it has turned out that these methods often have inherent vulnerabilities, which makes us cautious of the potential risks of using them for real-world applications such as autonomous driving. To reveal such vulnerabilities, we propose a method of simultaneously attacking monocular depth estimation and optical flow estimation, both of which are common artificial-intelligence-based tasks that are intensively investigated for autonomous driving scenarios. Our method can generate an adversarial patch that can fool CNN-based monocular depth estimation and optical flow estimation methods simultaneously by simply placing the patch in the input images. To the best of our knowledge, this is the first work to achieve simultaneous patch attacks on two or more CNNs developed for different tasks.

著者

澄川 靖信 ヤトフト アダム

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

電子情報通信学会論文誌 D (ISSN:18804535)

巻号頁・発行日

vol.J104-D, no.5, pp.486-497, 2021-05-01

---

歴史を理解することの重要性は広く認識されている.多くの人に知られている過去や地域史はTwitter上でも共有されているので,利用者ごとの関心に沿った歴史を提示できる対話システムが実現できると,多くの人に対して歴史への理解や関心を促進させることが期待できる.しかし,歴史学者ではない一般の人が気軽に歴史と対話できるシステムは実現されていない.本研究ではWikipediaから収集した過去の出来事をツイートするチャットボットを実現する.本チャットボットは,同じ日に起きた過去の出来事を定期的にツイートするだけでなく,利用者からのツイートに応じて適切な出来事をリプライする.また,利用者からのツイートが歴史に関するとき,そのツイートをリツイートして拡散する.本論文では,チャットボットの実現方法と,リツイートのために利用する分類器の訓練方法について述べる.訓練した分類器は再現率・適合率・F値の全てにおいて92%を超えることを確認した.

著者

Tuan Duong NGUYEN Marthinus Christoffel DU PLESSIS Takafumi KANAMORI Masashi SUGIYAMA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Information and Systems (ISSN:09168532)

巻号頁・発行日

vol.E97.D, no.7, pp.1822-1829, 2014 (Released:2014-07-01)

参考文献数

22

被引用文献数

2 5

---

We address the problem of estimating the difference between two probability densities. A naive approach is a two-step procedure that first estimates two densities separately and then computes their difference. However, such a two-step procedure does not necessarily work well because the first step is performed without regard to the second step and thus a small error in the first stage can cause a big error in the second stage. Recently, a single-shot method called the least-squares density-difference (LSDD) estimator has been proposed. LSDD directly estimates the density difference without separately estimating two densities, and it was demonstrated to outperform the two-step approach. In this paper, we propose a variation of LSDD called the constrained least-squares density-difference (CLSDD) estimator, and theoretically prove that CLSDD improves the accuracy of density difference estimation for correctly specified parametric models. The usefulness of the proposed method is also demonstrated experimentally.

著者

Masashi SUGIYAMA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Information and Systems (ISSN:09168532)

巻号頁・発行日

vol.E93.D, no.10, pp.2690-2701, 2010-10-01 (Released:2010-10-01)

参考文献数

36

被引用文献数

20 36

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Kernel logistic regression (KLR) is a powerful and flexible classification algorithm, which possesses an ability to provide the confidence of class prediction. However, its training—typically carried out by (quasi-)Newton methods—is rather time-consuming. In this paper, we propose an alternative probabilistic classification algorithm called Least-Squares Probabilistic Classifier (LSPC). KLR models the class-posterior probability by the log-linear combination of kernel functions and its parameters are learned by (regularized) maximum likelihood. In contrast, LSPC employs the linear combination of kernel functions and its parameters are learned by regularized least-squares fitting of the true class-posterior probability. Thanks to this linear regularized least-squares formulation, the solution of LSPC can be computed analytically just by solving a regularized system of linear equations in a class-wise manner. Thus LSPC is computationally very efficient and numerically stable. Through experiments, we show that the computation time of LSPC is faster than that of KLR by two orders of magnitude, with comparable classification accuracy.

著者

Ryoichi MORI Masaji KAWAHARA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS (1976-1990) (ISSN:00000000)

巻号頁・発行日

vol.E73-E, no.7, pp.1133-1146, 1990-07-25

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Superdistribution is an approach to distributing software in which software is made available freely and without restriction but is protected from modifications and modes of usage not authorized by its vendor. By eliminating the need of software vendors to protect their products against piracy through copy protection and similar measures, superdistribution promotes unrestricted distribution of software. The superdistribution architecture we have developed provides three principal functions: administrative arrangements for collecting accounting information on software usage and fees for software usage; an accounting process that records and accumulates usage charges, payments, and the allocation of usage charges among different software vendors; and a defense mechanism, utilizing digitally protected modules, that protects the system against interference with its proper operation. Superdistribution software is distributed over public channels in encrypted form. In order to participate in superdistribution, a computer must be equipped with an S-box--a digitally protected module containing microprocessors, RAM, ROM, and a real-time clock. The S-box preserves secret information such as a deciphering key and manages the proprietary aspects of the superdistribution system. A Software Usage Monitor insures the integrity of the system and keeps track of accounting information. The S-box can be realized as a digitally protected module in the form of a three-dimensional integrated circuit.

著者

Daijiro Koyama Yunzhuo Wang Nobuyasu Shiga Satoshi Yasuda Nicolas Chauvet Makoto Naruse

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

Nonlinear Theory and Its Applications, IEICE (ISSN:21854106)

巻号頁・発行日

vol.12, no.2, pp.225-235, 2021 (Released:2021-04-01)

参考文献数

9

---

The growing demand of high-bandwidth and low-latency information transfer in information and communication technologies such as data centers and in-vehicle networks has increased the importance of optical communication networks in recent years. However, complicated arbitration schemes can impose significant overheads in data transfer, which may inhibit the full exploitation of the potential of optical interconnects. Herein, we propose an arbitration protocol based on precision time synchronization via wireless two-way interferometry (Wi-Wi), and numerically validate its efficiency including the ability to impose a strict upper bound on the latency of data transfer. We introduce the notion of arbitration point (AP) for a designated time duration, which is shared by all nodes thanks to the time synchronization by Wi-Wi, to determine data transmission while ensuring avoiding collision. Compared with the conventional carrier sense multiple access/collision detection (CSMA/CD)-based approach, a significant improvement in the data transfer was observed especially in the cases with high traffic flow rate. Furthermore, we conducted a proof-of-principle experiment for Wi-Wi-based data transfer between two electrically connected nodes and confirmed that the skew was less than 300 ns and remained stable over time. Conversely, non-Wi-Wi-based data transfer exhibited huge and unstable skew. These results indicate that precision time synchronization is a promising resource to reduce the communication overheads and ensure low latency for future networks and real-time applications.

著者

旭 浩平 森 海里 中山 雅人 西浦 敬信

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

電子情報通信学会論文誌 D (ISSN:18804535)

巻号頁・発行日

vol.J104-D, no.4, pp.186-197, 2021-04-01

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パラメトリックスピーカは,音響信号の振幅によりキャリアと呼ばれる超音波を変調した振幅変調波を大音圧で放射することで超指向性を実現する.振幅変調波を放射すると,空気の非線形性により,音響信号が自己復調する.しかしながら,パラメトリックスピーカは空気の非線形性に基づいて音響信号を復調しているため,復調音の音圧が小さい.また,パラメトリックスピーカから振幅変調波を長時間放射することにより,超音波素子の疲労破壊が発生し,周波数ピーク雑音が発生する.そこで,本論文ではアドバンスドキャリアを用いてこれら問題を解決する手法を提案する.アドバンスドキャリアとはパラメトリックスピーカのもつ各問題点を解決するための最適なキャリアであり,キャリアの波形や周波数を目的に合わせて制御する特徴をもつ.具体的には,復調音の音圧を改善するために,キャリアの波形がもつエネルギーを増幅した矩形アドバンスドキャリアを最初に提案する.次に,周波数ピーク雑音を低減するために,キャリア周波数が超音波素子の共振周波数を中心に時間遷移する周波数アドバンスドキャリアを提案する.評価実験の結果,各提案手法の有効性を確認した.

著者

遠藤 駿 横川 慎二

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

電子情報通信学会論文誌 D (ISSN:18804535)

巻号頁・発行日

vol.J104-D, no.4, pp.318-327, 2021-04-01

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IoT技術の進展により,環境に関する多次元の時系列データを収集し,利活用する機会が増えている.ところが,多次元データの構造を可視化して把握することは容易ではない.従来法では,分析結果の図や表の数が増えてしまうことや,元データとの対応を考えることが困難になるという課題がある.このような多次元データの構造を可視化して比較的容易に把握することができれば,その結果を利用して様々なアクチュエータの制御に活用することや,深層学習の効率的な学習への応用が期待される.本論文では,大学附属図書館の施設内に設置された大量のセンサーから取得される多次元データに対して位相的データ解析(Topological Data Analysis; TDA)を適用し,対象エリアと近隣エリアのデータの関連性を可視化し,CO2濃度の上昇に寄与する要因を抽出した.本研究で提案する,TDAを用いたデータ構造の可視化によって元データとの対応を簡潔に表現する方法は,多次元時系列データの視覚的利用や応用に有用な結果を与えることがわかった.

著者

Hiroto SAIGO Hisashi KASHIMA Koji TSUDA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Information and Systems (ISSN:09168532)

巻号頁・発行日

vol.E96.D, no.8, pp.1766-1773, 2013-08-01 (Released:2013-08-01)

参考文献数

22

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Apriori-based mining algorithms enumerate frequent patterns efficiently, but the resulting large number of patterns makes it difficult to directly apply subsequent learning tasks. Recently, efficient iterative methods are proposed for mining discriminative patterns for classification and regression. These methods iteratively execute discriminative pattern mining algorithm and update example weights to emphasize on examples which received large errors in the previous iteration. In this paper, we study a family of loss functions that induces sparsity on example weights. Most of the resulting example weights become zeros, so we can eliminate those examples from discriminative pattern mining, leading to a significant decrease in search space and time. In computational experiments we compare and evaluate various loss functions in terms of the amount of sparsity induced and resulting speed-up obtained.

著者

Keita Onose Hiroto Kuriki Ryota Kimura Ryo Sawai

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Communications Express (ISSN:21870136)

巻号頁・発行日

pp.2021ETL0037, (Released:2021-03-29)

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In this letter, we propose an advanced incumbent protection method that considers three-dimensional aspects of 5G New Radio (NR) beamforming for dynamic spectrum access (DSA). The proposed method further introduces a concept of area-based protection to satisfy protection criteria for a primary system (PS) with inaccurate location information. We show some computer simulation results for deploying a 5G based secondary system (SS) in a millimeter-wave band which is primarily assigned to a fixed wireless access (FWA) based PS. The results demonstrate that the proposed method increases allowable transmission powers of the SS by up to 15 dB, compared to a conventional method.

著者

Koji YAMAMOTO

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Communications (ISSN:09168516)

巻号頁・発行日

vol.E98-B, no.9, pp.1804-1823, 2015-09-01

被引用文献数

63

---

Potential games form a class of non-cooperative games where the convergent of unilateral improvement dynamics is guaranteed in many practical cases. The potential game approach has been applied to a wide range of wireless network problems, particularly to a variety of channel assignment problems. In this paper, the properties of potential games are introduced, and games in wireless networks that have been proven to be potential games are comprehensively discussed.

著者

Ryoya Hirata Toshihiko Hirooka Masato Yoshida Masataka Nakazawa

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Electronics Express (ISSN:13492543)

巻号頁・発行日

vol.16, no.23, pp.20190664, 2019 (Released:2019-12-10)

参考文献数

30

被引用文献数

2 5

---

We present a wavelength-tunable ultrafast optical switch using a nonlinear optical loop mirror (NOLM), which has a low walk-off characteristic between the signal pulse and the control pulse thanks to the use of a dispersion-flattened highly nonlinear fiber. A 400-fs switching speed and an extinction ratio of >32 dB were obtained from 1528 to 1565 nm. The NOLM was applied to the 320 to 40 Gbaud demultiplexing of DQPSK Nyquist pulse signals, and error-free operation was achieved over the entire C-band.

著者

Tadachika OKI Satoshi TAOKA Toshiya MASHIMA Toshimasa WATANABE

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Information and Systems (ISSN:09168532)

巻号頁・発行日

vol.E95-D, no.3, pp.769-777, 2012-03-01

被引用文献数

1

---

The k-edge-connectivity augmentation problem with bipartition constraints (kECABP, for short) is defined by “Given an undirected graph G=(V, E) and a bipartition π = {VB, VW} of V with VB ∩ VW = ∅, find an edge set Ef of minimum cardinality, consisting of edges that connect VB and VW, such that G'=(V, E ∪ Ef) is k-edge-connected.” The problem has applications for security of statistical data stored in a cross tabulated table, and so on. In this paper we propose a fast algorithm for finding an optimal solution to (σ + 1)ECABP in O(|V||E| + |V2|log |V|) time when G is σ-edge-connected (σ > 0), and show that the problem can be solved in linear time if σ ∈ {1, 2}.

著者

Carlos MANSO Pol ALEMANY Ricard VILALTA Raul MUÑOZ Ramon CASELLAS Ricardo MARTÍNEZ

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Communications (ISSN:09168516)

巻号頁・発行日

vol.E104-B, no.3, pp.188-198, 2021-03-01

被引用文献数

2

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The need of telecommunications operators to reduce Capital and Operational Expenditures in networks which traffic is continuously growing has made them search for new alternatives to simplify and automate their procedures. Because of the different transport network segments and multiple layers, the deployment of end-to-end services is a complex task. Also, because of the multiple vendor existence, the control plane has not been fully homogenized, making end-to-end connectivity services a manual and slow process, and the allocation of computing resources across the entire network a difficult task. The new massive capacity requested by Data Centers and the new 5G connectivity services will urge for a better solution to orchestrate the transport network and the distributed computing resources. This article presents and demonstrates a Network Slicing solution together with an end-to-end service orchestration for transport networks. The Network Slicing solution permits the co-existence of virtual networks (one per service) over the same physical network to ensure the specific service requirements. The network orchestrator allows automated end-to-end services across multi-layer multi-domain network segments making use of the standard Transport API (TAPI) data model for both l0 and l2 layers. Both solutions will allow to keep up with beyond 5G services and the higher and faster demand of network and computing resources.

著者

Takao KONDO Shuto YOSHIHARA Kunitake KANEKO Fumio TERAOKA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Communications (ISSN:09168516)

巻号頁・発行日

vol.E101.B, no.8, pp.1853-1865, 2018-08-01 (Released:2018-08-01)

参考文献数

45

被引用文献数

1

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This paper argues that a layered approach is more suitable for Information Centric Networking (ICN) than a narrow-waist approach and proposes an ICN mechanism called ZINK. In ZINK, a location-independent content name is resolved to a list of node IDs of content servers in the application layer and a node ID is mapped to a node locator in the network layer, which results in scalable locator-based routing. An ID/Locator split approach in the network layer can efficiently support client/serever mobility. Efficient content transfer is achieved by using sophisticated functions in the transport layer such as multipath transfer for bandwidth aggregation or fault tolerance. Existing well-tuned congestion control in the transport layer achieves fairness not only among ICN flows but also among ICN flows and other flows. A proof-of concept prototype of ZINK is implemented on an IPv6 stack. Evaluation results show that the time for content finding is practical, efficient content transfer is possible by using multipath transfer, and the mobility support mechanism is scalable as shown in a nationwide experiment environment in Japan.