著者
道下 尚文
出版者
一般社団法人 電子情報通信学会
雑誌
電子情報通信学会 通信ソサイエティマガジン (ISSN:21860661)
巻号頁・発行日
vol.2010, no.15, pp.15_18-15_24, 2010-11-25 (Released:2011-06-01)
参考文献数
24

近年,左手系媒質あるいは負屈折率媒質と呼ばれるメタマテリアルに関する研究が非常に盛んである.メタマテリアルでは誘電率と透磁率が同時に負となる周波数領域で電磁波は伝搬できる.誘電率あるいは透磁率のどちらか一方のみが負となる場合,電波は伝搬することができない.このように,メタマテリアル技術を用いると電磁波の伝搬の設計範囲が広がることから,アンテナやマイクロ波回路の分野で様々な応用例が報告されている.本論文では,電波を遮断する周波数帯域を持つEBG(Electromagnetic Band Gap,電磁バンドギャップ)構造について解説する.
著者
Changki LEE
出版者
一般社団法人 電子情報通信学会
雑誌
IEICE Transactions on Information and Systems (ISSN:09168532)
巻号頁・発行日
vol.E100.D, no.4, pp.882-887, 2017-04-01 (Released:2017-04-01)
参考文献数
14
被引用文献数
2

Recurrent neural networks (RNNs) are a powerful model for sequential data. RNNs that use long short-term memory (LSTM) cells have proven effective in handwriting recognition, language modeling, speech recognition, and language comprehension tasks. In this study, we propose LSTM conditional random fields (LSTM-CRF); it is an LSTM-based RNN model that uses output-label dependencies with transition features and a CRF-like sequence-level objective function. We also propose variations to the LSTM-CRF model using a gate recurrent unit (GRU) and structurally constrained recurrent network (SCRN). Empirical results reveal that our proposed models attain state-of-the-art performance for named entity recognition.
著者
Tadashi MATSUO Nobutaka SHIMADA
出版者
一般社団法人 電子情報通信学会
雑誌
IEICE Transactions on Information and Systems (ISSN:09168532)
巻号頁・発行日
vol.E100.D, no.6, pp.1350-1359, 2017-06-01 (Released:2017-06-01)
参考文献数
27
被引用文献数
2

Appearance-based generic object recognition is a challenging problem because all possible appearances of objects cannot be registered, especially as new objects are produced every day. Function of objects, however, has a comparatively small number of prototypes. Therefore, function-based classification of new objects could be a valuable tool for generic object recognition. Object functions are closely related to hand-object interactions during handling of a functional object; i.e., how the hand approaches the object, which parts of the object and contact the hand, and the shape of the hand during interaction. Hand-object interactions are helpful for modeling object functions. However, it is difficult to assign discrete labels to interactions because an object shape and grasping hand-postures intrinsically have continuous variations. To describe these interactions, we propose the interaction descriptor space which is acquired from unlabeled appearances of human hand-object interactions. By using interaction descriptors, we can numerically describe the relation between an object's appearance and its possible interaction with the hand. The model infers the quantitative state of the interaction from the object image alone. It also identifies the parts of objects designed for hand interactions such as grips and handles. We demonstrate that the proposed method can unsupervisedly generate interaction descriptors that make clusters corresponding to interaction types. And also we demonstrate that the model can infer possible hand-object interactions.
著者
Rong-Long WANG Xiao-Fan ZHOU Kozo OKAZAKI
出版者
一般社団法人 電子情報通信学会
雑誌
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)
巻号頁・発行日
vol.E92.A, no.5, pp.1368-1372, 2009-05-01 (Released:2009-05-01)
参考文献数
15
被引用文献数
1 1 1

Ant colony optimization (ACO) algorithms are a recently developed, population-based approach which has been successfully applied to optimization problems. However, in the ACO algorithms it is difficult to adjust the balance between intensification and diversification and thus the performance is not always very well. In this work, we propose an improved ACO algorithm in which some of ants can evolve by performing genetic operation, and the balance between intensification and diversification can be adjusted by numbers of ants which perform genetic operation. The proposed algorithm is tested by simulating the Traveling Salesman Problem (TSP). Experimental studies show that the proposed ACO algorithm with genetic operation has superior performance when compared to other existing ACO algorithms.
著者
上田 修
出版者
一般社団法人 電子情報通信学会
雑誌
電子情報通信学会 基礎・境界ソサイエティ Fundamentals Review (ISSN:18820875)
巻号頁・発行日
vol.6, no.4, pp.294-304, 2013-04-01 (Released:2013-04-01)
参考文献数
25

各種化合物半導体多層薄膜から作製されたLEDや半導体レーザといった半導体発光デバイスは,現在,社会,産業,家庭における様々なシステムや機器に搭載されている.このような発光デバイスは,機器への不適切な実装や過酷な条件での使用などで劣化し,機器やシステムの不具合や障害,事故の原因となる.そこで,本稿では,赤色・赤外デバイスを中心とした発光デバイスの種々の劣化モードについて,劣化メカニズム,解析事例,及び抑制方法について解説する.
著者
Koji Iwayama Yoshito Hirata Hideyuki Suzuki Kazuyuki Aihara
出版者
一般社団法人 電子情報通信学会
雑誌
Nonlinear Theory and Its Applications, IEICE (ISSN:21854106)
巻号頁・発行日
vol.4, no.2, pp.160-171, 2013 (Released:2013-04-01)
参考文献数
40
被引用文献数
2 3

Change-point detection based on an observed time series has emerged as an important method for detecting changes in dynamics of real-world systems. Recently, recurrence networks have been shown to be useful, which are network representations of recurrences, to analyze underlying dynamics. In this paper, we propose a new method for detecting dynamical changes using recurrence networks. The proposed method extracts a group of time indices that share the same dynamics as a community of the recurrence network. In addition, some numerical simulations are presented to verify the validity of this method.
著者
Takeshi Fujino Takaya Kubota Mitsuru Shiozaki
出版者
一般社団法人 電子情報通信学会
雑誌
IEICE Electronics Express (ISSN:13492543)
巻号頁・発行日
vol.14, no.2, pp.20162004-20162004, 2017 (Released:2017-01-25)
参考文献数
20

Cryptosystems are widely used for achieving data confidentiality and authenticated access control. Recent cryptographic algorithms such as AES or RSA are computationally safe in the sense that it is practically impossible to reveal key information from a pair of plain and cipher texts if a key of sufficient length is used. A malicious attacker aims to reveal a key by exploiting implementation flaws in cryptographic modules. Even if there are no flaws in the software, the attacker will try to extract a secret key stored in the security hardware. The side-channel attacks (SCAs) are low cost and powerful against cryptographic hardware. The attacker exploits side-channel information such as power or electro-magnetic emission traces on the cryptographic circuits. In this paper, we will introduce the principle of SCAs and the countermeasures against SCAs.
著者
Yuichi Togashi
出版者
一般社団法人 電子情報通信学会
雑誌
Nonlinear Theory and Its Applications, IEICE (ISSN:21854106)
巻号頁・発行日
vol.7, no.2, pp.190-201, 2016 (Released:2016-04-01)
参考文献数
38
被引用文献数
1

Owing to recent progress in structural biology, the structures of a number of proteins have been resolved and deposited into databases such as the Protein Data Bank (PDB). Many proteins function as molecular machines or show allosteric effects, which require integrated communication between different parts of the protein structure;however, the general principles underlying such communication are not yet clear. All-atom molecular dynamics simulation is a powerful tool for tracking molecular motion, but is still far too computationally costly to be applied widely. In this paper, we present a simple method for assessing the properties of mechanical communications using coarse-grained steered molecular dynamics simulations with elastic network models. The method was tested by screening for a certain mechanical property among protein structures in the PDB.
著者
植松 友彦
出版者
一般社団法人 電子情報通信学会
雑誌
電子情報通信学会 基礎・境界ソサイエティ Fundamentals Review (ISSN:18820875)
巻号頁・発行日
vol.4, no.2, pp.123-128, 2010-10-01 (Released:2010-12-01)
参考文献数
62

シャノンによる情報通信のマグナカルタ “A mathematical theory of communication” が発表されてから60年以上を経た.本稿では,シャノンが最初に創造した情報理論の枠組みについて解説した後,いつだれによって基本定理の厳密な証明がなされたか,並びに情報理論がどのような発展の経路をたどってシャノンの後にどこまで到達したかについて解説している.
著者
鳥屋尾 博 小林 準人 安藤 利和 半杭 英二
出版者
一般社団法人 電子情報通信学会
雑誌
電子情報通信学会 通信ソサイエティマガジン (ISSN:21860661)
巻号頁・発行日
vol.9, no.1, pp.27-32, 2015-06-01 (Released:2015-06-01)
参考文献数
7

小形化が進む無線機器の内部では,電磁ノイズによって生じる干渉の低減が課題となっている.メタマテリアルの一種である電磁バンドギャップ (EBG) 構造は,この電磁ノイズの放射を抑制する新たな技術として注目を集めている.本稿では,メタマテリアル技術の産業応用の例として,これまでに提案されているEBG構造の種類や原理を中心に,筆者らによるEBG構造の応用事例も含めて紹介する.更に試作機レベルでの電磁ノイズ抑制効果についても評価結果を示して解説する.
著者
Ikkyu Aihara Yasufumi Yamada Emyo Fujioka Shizuko Hiryu
出版者
一般社団法人 電子情報通信学会
雑誌
Nonlinear Theory and Its Applications, IEICE (ISSN:21854106)
巻号頁・発行日
vol.6, no.2, pp.313-328, 2015 (Released:2015-04-01)
参考文献数
14

A mathematical model is proposed to describe the nonlinear dynamics of the echolocation behavior of a bat during free flight in an enclosed chamber. In the model, a bat dynamically controls its flight and pulse directions (φf and φp respectively), to avoid collision with multiple walls of the chamber; namely, the bat varies φf and φp repulsively from the closest wall, minimizing the difference between φf and φp. Numerical simulation of the model with specific parameter values demonstrates that the bat can successfully fly in the chamber while emitting pulses along the inner periphery of an eight-shaped flight path, which is consistent with the results of a behavioral experiment conducted by using a Japanese house bat (Pipistrellus abramus).
著者
Shuhei AMAKAWA
出版者
一般社団法人 電子情報通信学会
雑誌
IEICE Transactions on Electronics (ISSN:09168524)
巻号頁・発行日
vol.E99.C, no.10, pp.1100-1112, 2016-10-01 (Released:2016-10-01)
参考文献数
79

The most commonly used scattering parameters (S parameters) are normalized to a real reference resistance, typically 50Ω. In some cases, the use of S parameters normalized to some complex reference impedance is essential or convenient. But there are different definitions of complex-referenced S parameters that are incompatible with each other and serve different purposes. To make matters worse, different simulators implement different ones and which ones are implemented is rarely properly documented. What are possible scenarios in which using the right one matters? This tutorial-style paper is meant as an informal and not overly technical exposition of some such confusing aspects of S parameters, for those who have a basic familiarity with the ordinary, real-referenced S parameters.
著者
IWAMOTO Chuzo MATSUI Yuta
出版者
一般社団法人 電子情報通信学会
雑誌
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)
巻号頁・発行日
vol.99, no.6, pp.1145-1148, 2016
被引用文献数
1

The Building puzzle is played on an N×N grid of cells. Initially, some numbers are given around the border of the grid. The object of the puzzle is to fill out blank cells such that every row and column contains the numbers 1 through N. The number written in each cell represents the height of the building. The numbers around the border indicate the number of buildings which a person can see from that direction. A shorter building behind a taller one cannot be seen by him. It is shown that deciding whether the Building puzzle has a solution is NP-complete.
著者
S. S. Gupta R. Senani
出版者
一般社団法人 電子情報通信学会
雑誌
IEICE Electronics Express (ISSN:13492543)
巻号頁・発行日
vol.1, no.16, pp.507-512, 2004 (Released:2004-11-25)
参考文献数
15
被引用文献数
10 12

Recently, the authors introduced two new second-order single-resistance-controlled oscillators (SRCO) employing four/three unity-gain cells (unity-gain voltage followers and unity-gain current followers). In this communication, a novel family of SRCOs has been presented which employ a reduced number of (only two) unity-gain cells as active elements. The workability of the new circuits has been confirmed by the SPICE simulations of their CMOS-implementable versions.