著者

小泉 達寛 山田 寛喜 藤井 智史 長名 保範 宇野 亨

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.J105-B, no.7, pp.519-520, 2022-07-01

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波浪の観測を目的とした海洋レーダは,通常,垂直偏波で運用される.筆者らは,広い海域を観測できる海洋レーダの特長を生かしたマルチユース化の可能性を検証するため,偏波海洋レーダを開発した.本論文では,そのレーダの概要と実験結果を報告する.

著者

西山 英輔 豊田 一彦

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.J106-B, no.5, pp.317-326, 2023-05-01

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現在,IoT,近距離通信や無線センサネットワークなど無線を利用したシステムの多様化や5Gの実用化でアンテナの性能・機能の向上が求められている.例えば,指向性可変機能化,ビーム走査機能化,マルチバンド化,広帯域化やアダプティブアレー化などの多機能化が挙げられる.本論文では,アンテナの多機能化の手段としてアンテナとマイクロ波機能回路の複合技術を活用した平面型の多機能アンテナに注目する.このアンテナでは,多機能化のためにアンテナの直交共振モードを活用する.直交共振モードはお互いに独立であるために,その組み合わせで自在に所望の共振姿態を形成できる.マイクロ波機能回路は,アンテナに生じる直交する複数の共振モードを切替や合成するために活用する.ここでは,アンテナとマイクロ波機能回路との複合技術について説明し,それらを体系的にまとめている.また,アンテナとマイクロ波機能回路の複合による多機能アンテナの実際について概説する.

著者

Yasunobu TOYOTA Wataru MISHIMA Koichiro KANAYA Osamu NAKAMURA

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.E106.D, no.5, pp.927-939, 2023-05-01 (Released:2023-05-01)

参考文献数

46

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QoS of applications is essential for content providers, and it is required to improve the end-to-end communication quality from a content provider to users. Generally, a content provider's data center network is connected to multiple ASes and has multiple egress paths to reach the content user's network. However, on the Internet, the communication quality of network paths outside of the provider's administrative domain is a black box, so multiple egress paths cannot be quantitatively compared. In addition, it is impossible to determine a unique egress path within a network domain because the parameters that affect the QoS of the content are different for each network. We propose a “Performance Aware Egress Path Discovery” method to improve QoS for content providers. The proposed method uses two techniques: Egress Peer Engineering with Segment Routing over IPv6 and Passive End-to-End Measurement. The method is superior in that it allows various metrics depending on the type of content and can be used for measurements without affecting existing systems. To evaluate our method, we deployed the Performance Aware Egress Path Discovery System in an existing content provider network and conducted experiments to provide production services. Our findings from the experiment show that, in this network, 15.9% of users can expect a 30Mbps throughput improvement, and 13.7% of users can expect a 10ms RTT improvement.

著者

Masanori MORISE Fumiya YOKOMORI Kenji OZAWA

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.E99.D, no.7, pp.1877-1884, 2016-07-01 (Released:2016-07-01)

参考文献数

38

被引用文献数

91 571

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A vocoder-based speech synthesis system, named WORLD, was developed in an effort to improve the sound quality of real-time applications using speech. Speech analysis, manipulation, and synthesis on the basis of vocoders are used in various kinds of speech research. Although several high-quality speech synthesis systems have been developed, real-time processing has been difficult with them because of their high computational costs. This new speech synthesis system has not only sound quality but also quick processing. It consists of three analysis algorithms and one synthesis algorithm proposed in our previous research. The effectiveness of the system was evaluated by comparing its output with against natural speech including consonants. Its processing speed was also compared with those of conventional systems. The results showed that WORLD was superior to the other systems in terms of both sound quality and processing speed. In particular, it was over ten times faster than the conventional systems, and the real time factor (RTF) indicated that it was fast enough for real-time processing.

著者

Kentaro YOSHIOKA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Electronics (ISSN:09168524)

巻号頁・発行日

pp.2021CTI0002, (Released:2022-04-11)

被引用文献数

5

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LiDAR is a distance sensor that plays a key role in the realization of advanced driver assistance systems (ADAS). In this paper, we present a tutorial and review of automotive direct time of flight (dToF) LiDAR from the aspect of circuit systems. We discuss the breakthrough in ADAS LiDARs through comparison with the first-generation LiDAR systems, which were conventionally high-cost and had an immature performance. We define current high-performance and low-cost LiDARs as next-generation LiDAR systems, which have significantly improved the cost and performance by integrating the photodetector, the readout circuit, and the signal processing unit into a single SoC.This paper targets reader who is new to ADAS LiDARs and will cover the basic principles of LiDAR, also comparing with range methods other than dToF. In addition, we discuss the development of this area through the latest research examples such as the 2-chip approach, 2D SPAD array, and 3D integrated LiDARs.

著者

宇都 雅輝

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.J105-D, no.7, pp.457-469, 2022-07-01

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近年,論理的思考力や表現力といった被評価者の実践的な能力を測定する手法の一つとして,ルーブリックを用いたパフォーマンス評価が注目されている.ルーブリックの利用により評価者間の採点基準のばらつきを低減できると期待されるが,それでも評価結果がパフォーマンス課題や評価者,ルーブリックの評価観点の特性の影響を受けることが指摘されている.この問題を解決する方法の一つとして,課題や評価者,評価観点の特性を考慮して被評価者の能力を推定できる項目反応モデルが提案されてきた.それらの既存モデルの多くは測定対象の能力に一次元性を仮定しているが,高次な能力の測定を目的とするルーブリックを用いたパフォーマンス評価では測定対象の能力に多次元性が想定される場合がある.そのような能力の多次元性に対応できる項目反応モデルも提案されているが,既存のモデルでは課題と評価者,評価観点の特性を同時に考慮した能力推定は実現できない.そこで,本論文では,課題・評価者・評価観点の特性を同時に考慮して多次元尺度上で被評価者の能力を推定できる項目反応モデルを提案する.また,シミュレーション実験と実データ実験を通して提案モデルの有効性を示す.

著者

Atsuo Maki Yuu Miino Naoya Umeda Masahiro Sakai Tetsushi Ueta Hiroshi Kawakami

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.13, no.1, pp.2-24, 2022 (Released:2022-01-01)

参考文献数

53

被引用文献数

2

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Capsizing is one of the worst scenarios in oceangoing vessels. It could lead to a high number of fatalities. A considerable number of studies have been conducted until the 1980s, and one of the discoveries is the weather criterion established by the International Maritime Organization (IMO). In the past, one of the biggest difficulties in revealing the behavior of ship-roll motion was the nonlinearity of the governing equation. On the other hand, after the mid-1980s, the complexity of the capsizing problem was uncovered with the aid of computers. In this study, we present the theoretical backgrounds of the capsizing problem from the viewpoint of nonlinear dynamics. Then, we discuss the theoretical conditions and mechanisms of the bifurcations of periodic solutions and numerical attempts for the bifurcations and capsizing.

著者

ShiWei Yuan Lei Li Ji Yang Yuanhang He WanTing Zhou Jin Li

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Electronics Express (ISSN:13492543)

巻号頁・発行日

pp.18.20210098, (Released:2021-04-20)

参考文献数

30

被引用文献数

3

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Hardware trojans(HT) is one of the main threats for hardware security, especially attacks on General-Purpose Registers(GPRs) of processors. This paper presented a novel method to detect HT induced attacks by comparing the states of GPRs with an embedded reference model in real time. Firstly, the instruction sequence was realigned with four principles. Secondly, based on the realigned instruction stream, a reference model for GPRs was built. Finally, HT induced attacks on GPRs can be detected by comparing the expected GPRs’ state from the reference model with the sampled GPRs’ state from processors. We integrated this method into a RISC-V core of PULpino and investigated the feasibility with different programs. The experimental results showed that all the randomly inserted HT attacks can be detected in real time with the latency of two clock cycles.

著者

松本 鮎美 三上 弾 木全 英明

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

電子情報通信学会論文誌 D (ISSN:18804535)

巻号頁・発行日

vol.J101-D, no.10, pp.1448-1461, 2018-10-01

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本論文では,スポーツ映像を対象として,動作中のイベントの発生タイミングを時間的に詳細に検出することを目指し,映像を疑似的に高フレームレート化した上で,高フレームレート化された映像からイベントを検出する手法を提案する.一般的に,スポーツの動作は非常に高速である.例えば野球において投手のボールのリリースタイミングを分析することを考えると,フレームとフレームの間で撮影されていない可能性がある.一般的な映像からのイベント検出手法の時間分解能は映像のフレームレートに制約されてしまう.この問題を解決するために我々は,低次元特徴に着目し,低次元特徴空間における映像の疑似高フレームレート化による高い時間分解能でのイベントタイミング検出方法を提案する.これは,映像をダイナミックスを保持したまま低次元特徴空間へマッピングするものであり,これにより高フレームレート化が容易となり,フレームレートより詳細なレベルでのイベントのタイミング検出が可能となる.更に,クラスタリングによるアノテーションを行うデータの自動抽出と,ストリームデータに対する逐次的なアノテーションの導入により,実環境での利用への拡張を行う.

著者

Takashi SHIBATA Kazunori SATO Ryohei IKEJIRI

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Electronics (ISSN:09168524)

巻号頁・発行日

vol.E100.C, no.11, pp.1012-1020, 2017-11-01 (Released:2017-11-01)

参考文献数

20

被引用文献数

2

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We conducted experimental classes in an elementary school to examine how the advantages of using stereoscopic 3D images could be applied in education. More specifically, we selected a unit of the Tumulus period in Japan for sixth-graders as the source of our 3D educational materials. This unit represents part of the coursework for the topic of Japanese history. The educational materials used in our study included stereoscopic 3D images for examining the stone chambers and Haniwa (i.e., terracotta clay figures) of the Tumulus period. The results of our experimental class showed that 3D educational materials helped students focus on specific parts in images such as attached objects of the Haniwa and also understand 3D spaces and concavo-convex shapes. The experimental class revealed that 3D educational materials also helped students come up with novel questions regarding attached objects of the Haniwa, and Haniwa's spatial balance and spatial alignment. The results suggest that the educational use of stereoscopic 3D images is worthwhile in that they lead to question and hypothesis generation and an inquiry-based learning approach to history.

著者

Hiroki TAMARU Yuki SAITO Shinnosuke TAKAMICHI Tomoki KORIYAMA Hiroshi SARUWATARI

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.3, pp.639-647, 2020-03-01 (Released:2020-03-01)

参考文献数

32

被引用文献数

3

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This paper proposes a generative moment matching network (GMMN)-based post-filtering method for providing inter-utterance pitch variation to singing voices and discusses its application to our developed mixing method called neural double-tracking (NDT). When a human singer sings and records the same song twice, there is a difference between the two recordings. The difference, which is called inter-utterance variation, enriches the performer's musical expression and the audience's experience. For example, it makes every concert special because it never recurs in exactly the same manner. Inter-utterance variation enables a mixing method called double-tracking (DT). With DT, the same phrase is recorded twice, then the two recordings are mixed to give richness to singing voices. However, in synthesized singing voices, which are commonly used to create music, there is no inter-utterance variation because the synthesis process is deterministic. There is also no inter-utterance variation when only one voice is recorded. Although there is a signal processing-based method called artificial DT (ADT) to layer singing voices, the signal processing results in unnatural sound artifacts. To solve these problems, we propose a post-filtering method for randomly modulating synthesized or natural singing voices as if the singer sang again. The post-filter built with our method models the inter-utterance pitch variation of human singing voices using a conditional GMMN. Evaluation results indicate that 1) the proposed method provides perceptible and natural inter-utterance variation to synthesized singing voices and that 2) our NDT exhibits higher double-trackedness than ADT when applied to both synthesized and natural singing voices.

著者

Yuki SAITO Kei AKUZAWA Kentaro TACHIBANA

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.9, pp.1978-1987, 2020-09-01

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This paper presents a method for many-to-one voice conversion using phonetic posteriorgrams (PPGs) based on an adversarial training of deep neural networks (DNNs). A conventional method for many-to-one VC can learn a mapping function from input acoustic features to target acoustic features through separately trained DNN-based speech recognition and synthesis models. However, 1) the differences among speakers observed in PPGs and 2) an over-smoothing effect of generated acoustic features degrade the converted speech quality. Our method performs a domain-adversarial training of the recognition model for reducing the PPG differences. In addition, it incorporates a generative adversarial network into the training of the synthesis model for alleviating the over-smoothing effect. Unlike the conventional method, ours jointly trains the recognition and synthesis models so that they are optimized for many-to-one VC. Experimental evaluation demonstrates that the proposed method significantly improves the converted speech quality compared with conventional VC methods.

著者

松原 靖子 櫻井 保志 Christos FALOUTSOS

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.J100-D, no.4, pp.457-471, 2017-04-01

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本論文では,大規模オンライン活動データのための非線形解析手法であるECOWEB (Ecosystem on the Web)について述べる.本研究では,“Xbox”, “PlayStation”, “Wii”等のオンライン検索キーワードの出現件数に関する時系列データが与えられたとき,それらのキーワード間の潜在的な関連性や競合性,そして季節性等の重要なパターンを自動抽出することを目的とする.より具体的には,オンラインユーザ活動の推移パターンを,自然界の生態系における種内・種間競争として捉えることで,潜在的なユーザ資源(ユーザの興味,時間等)を各アクティビティ(Xbox等のキーワード)がどのように共有,あるいは競合しているかを非線形動的システムとして表現する.実データを用いた実験では,ECOWEB が様々なオンライン活動における長期的な非線形パターンや季節性等の重要なトレンドを発見し,更に,長期的な将来予測を高精度に行うことを確認した.

著者

Sho ENDO Jun SONODA Motoyuki SATO Takafumi AOKI

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.E94-D, no.12, pp.2338-2344, 2011-12-01

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Finite difference time domain (FDTD) method has been accelerated on the Cell Broadband Engine (Cell B.E.). However the problem has arisen that speedup is limited by the bandwidth of the main memory on large-scale analysis. As described in this paper, we propose a novel algorithm and implement FDTD using it. We compared the novel algorithm with results obtained using region segmentation, thereby demonstrating that the proposed algorithm has shorter calculation time than that provided by region segmentation.

著者

Shinichi MOGAMI Yoshiki MITSUI Norihiro TAKAMUNE Daichi KITAMURA Hiroshi SARUWATARI Yu TAKAHASHI Kazunobu KONDO Hiroaki NAKAJIMA Hirokazu KAMEOKA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)

巻号頁・発行日

vol.E102-A, no.2, pp.458-463, 2019-02-01

被引用文献数

5

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In this letter, we propose a new blind source separation method, independent low-rank matrix analysis based on generalized Kullback-Leibler divergence. This method assumes a time-frequency-varying complex Poisson distribution as the source generative model, which yields convex optimization in the spectrogram estimation. The experimental evaluation confirms the proposed method's efficacy.

著者

Junichi Akita

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Electronics Express (ISSN:13492543)

巻号頁・発行日

pp.15.20180785, (Released:2018-10-24)

参考文献数

10

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Eye tracking, or detecting where the user is looking at, is expected as a new type of user interfaces, with including the phenomenon of rapid eye movement, so called saccade. However, real-time tracking of saccade is difficult with the conventional image processing systems for their long processing time and latency against the speed of saccade. In this paper, we describe the design of the CMOS image sensor for eye tracking with high speed and low latency capability, as well as its evaluation results.

著者

Takashi SHIBATA Kazunori SATO Ryohei IKEJIRI

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Electronics (ISSN:09168516)

巻号頁・発行日

vol.E100-C, no.11, pp.1012-1020, 2017-11-01

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We conducted experimental classes in an elementary school to examine how the advantages of using stereoscopic 3D images could be applied in education. More specifically, we selected a unit of the Tumulus period in Japan for sixth-graders as the source of our 3D educational materials. This unit represents part of the coursework for the topic of Japanese history. The educational materials used in our study included stereoscopic 3D images for examining the stone chambers and Haniwa (i.e., terracotta clay figures) of the Tumulus period. The results of our experimental class showed that 3D educational materials helped students focus on specific parts in images such as attached objects of the Haniwa and also understand 3D spaces and concavo-convex shapes. The experimental class revealed that 3D educational materials also helped students come up with novel questions regarding attached objects of the Haniwa, and Haniwa's spatial balance and spatial alignment. The results suggest that the educational use of stereoscopic 3D images is worthwhile in that they lead to question and hypothesis generation and an inquiry-based learning approach to history.

著者

則 のぞみ 鹿島 久嗣 山下 和人 猪飼 宏 今中 雄一

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.J100-D, no.2, pp.194-204, 2017-02-01

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ICU入室患者の死亡リスク予測問題において,疾病によってリスク要因がどのように死亡リスクに関係するかが異なる点を考慮するために,疾病ごとに個別化した予測モデルを構築する.疾病ごとの個別化に際して課題となるデータの疎性に対処するために,疾病の分類と電子健康記録の分類に関する二つのドメイン知識を取り込むマルチタスク学習手法を提案し,医療機関における実データを用いた実験で提案手法の有効性を示す.

著者

呉 承彦 安倍 広多 石橋 勇人 松浦 敏雄

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.J97-B, no.10, pp.849-860, 2014-10-01

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構造化P2Pネットワークでは,各ノードが保持する経路表を用いてルーティングを行い宛先ノードに到達する.既存の多くの構造化P2Pネットワークでは,経路長はノード数nに対してO(logk n)であるが,対数の底kはP2Pネットワークの運用中に変更できるものは知られていない.本論文では,構造化P2Pネットワークの一つであるChord#の経路表(finger table)を拡張することでkの値を動的に変更可能な経路表構築手法を提案する.また,拡張したfinger tableを用いて,最大経路長が指定した任意の値を上回らないようにする方式(経路長優先方式)と,経路表サイズを指定した任意の値とする方式(経路表サイズ優先方式)を実現した.これらの方式により,定数ホップ及び対数ホップルーティングが可能である.提案手法の有効性はシミュレーションにより確認した.

著者

鳥海 不二夫 神谷 達幸 石井 健一郎

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.J94-D, no.11, pp.1740-1750, 2011-11-01

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近年,SNS (Social Networking Service)やBlog,Twitterなどのインターネットを利用したコミュニケーションツールの利用が拡大している.SNSのユーザは友人登録機能によってSNS上での他のユーザとの関係を表現する.このようにSNS上に現れる友人関係は,実社会において観測することの困難な人間関係を限定的ではあるが具現化する可能性がある.本研究では性質の異なる多数の小規模SNSを表現可能なネットワーク生成モデルを提案した.提案モデルは,SNSの成長モデルとして知られているCNN+Fitnessモデルに,管理者優先モデル,トライアドフォーメーションモデル,優先的近傍接続モデルを組み合わせて作られた.そして,それぞれのモデル適用率をパラメータとし,モデル化したいSNSに特化して最適化することで,現実の友人ネットワークの構造を近似する.パラメータの最適化にはSimulated Annealingを利用した.また,提案モデルの近似性能を確認するために,ネットワーク指標間の距離に基づいた評価関数を提案した.提案モデルを279の小規模SNSに適用し,提案評価関数で評価した結果,従来のモデルよりも高い精度で小規模SNSの友人ネットワークを近似できることを確認した.また,提案した3種類のモデルについて有効性を確認したところ,管理者優先モデル,優先的近傍接続モデルは友人ネットワーク生成モデル構築上重要であったが,トライアドフォーメーションモデルはネットワークの生成にほとんど寄与しないことが明らかとなった.