研究者詳細 - 山田　寛喜

論文 - 山田　寛喜

分割表示 893 件中 121 - 140 件目／全件表示 >>

動きのある人物の屋内位置推定に関する実験的検討

佐藤耕平, 山田寛喜, 山口芳雄

電子情報通信学会総合大会 ( B-1-219 ) 2014年3月

PolInSAR Coherence Estimation Based on Best Normal Matrix Approximation

Y.Cui, H.Yamada, S.Park, Y.Yamaguchi, R.Sato

第582回URSI-F会合 2014年3月

Very Large MIMOのための多素子リニアアレーの素子間相互結合に関する考察

板橋慎二, 山田寛喜, 西森健太郎, 山口芳雄

電子情報通信学会技術研究報告 AP2013-187 ( 3 ) 13 - 18 2014年3月

XバンドPi-SAR2画像における降雨による後方散乱の変化に関する検討

佐藤大輔, 渡邊卓磨, Cui Yi, 山田寛喜, 山口芳雄

電子情報通信学会総合大会 ( B-2-56 ) 2014年3月

多素子リニアアレーにおける素子間相互結合によるビームスティアリング誤差評価

板橋慎二, 山田寛喜, 西森健太郎, 山口芳雄

電子情報通信学会総合大会 ( B-1-187 ) 2014年3月

Webカメラによる参照信号位置推定を利用したアレーアンテナ校正法の実験的検討

石山優, 山田寛喜, 山口芳雄

電子情報通信学会総合大会 ( B-1-188 ) 2014年3月

FM-CWレーダによるドップラ周波数推定に基づくモーションセンシングの実験的検討

福島真也, 山田寛喜, 山口芳雄, 小林弘一

電子情報通信学会総合大会 ( B-1-200 ) 2014年3月

CSIフィードバックを不要とするキャリブレーション回路によるMassive MIMO伝送の基本特性

西森健太郎, 山田寛喜

電子情報通信学会技術研究報告 AP2013-181 ( 2 ) 2014年2月

POLSAR画像のための散乱モデル分解アルゴリズムの特性比較査読

佐藤,渡邉, 山田,パク,山口

電子情報通信学会和文論文誌B J97-B ( 2 ) 192 - 201 2014年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人電子情報通信学会

偏波合成開口レーダ(Polarimetric SAR: POLSAR)により取得された散乱行列の解析手法の一つに散乱モデル分解法がある.これは実験や理論から導出された散乱モデルに取得された散乱行列を当てはめることで散乱成分の電力寄与を求める手法である.現在も研究が進められており,多くの手法が提案されている.しかしながら,散乱モデル分解法は散乱モデルや電力寄与の推定方法により解析結果の電力成分比が異なり,ある観測領域に対してどの手法が最も優れているかを一概に判断することは難しい.そのため,散乱モデル分解法を用いた画像解析では各手法がどのようなターゲットの検出・分離推定に適しているかを理解しておく必要がある.本検討では,近年提案されたものを含めて代表的な散乱モデル分解法について,各々の解析手法がどのような散乱メカニズムの検出に適しているかを明らかにするため,森林領域,市街他領域のPOLSAR画像データを解析し,その解析画像の視覚的な違い,負の電力の発生,散乱電力の成分比という観点からそれぞれの特性を比較検討した.

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Wideband DOA estimation algorithm for linear arrays using KR matrix product 査読

H. Yamada, S. Shirai, Y. Yamaguchi

Proc. Vietnam-Japan International Symposium on Antennas and Propagation 2014年1月

Throughput performance on IEEE802.11ac based massive MIMO considering calibration errors 査読

Kentaro Nishimori, Takefumi Hiraguri, Toshiyuki Ogawa, Hiroyoshi Yamada

2014 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP) 395 - 396 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper describes the effectiveness of calibration technique for implicit beamforming which enables the transmission without the channel state information (CSI) feedback in massive MIMO system. First, we address the calibration technique using the circulation of self transmit signal. The effectiveness of calibration method is next verified by using 16-element testbed for the massive MIMO system. Finally, the throughput performance by the IEEE802.11ac based massive MIMO transmission with and without CSI feedback is verified when considering calibration errors which are obtained by the testbed.

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Massive MIMO transmission by calibration circuit eliminating CSI feedback 査読

Satoshi Sasaki, Kentaro Nishimori, Hiroyoshi Yamada

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 225 - 226 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

In massive MIMO transmission, implicit beam forming was studied to eliminate channel state information (CSI) feedback. However, it is essential to introduce the calibration circuit which compensates the difference of complex amplitudes between the transmitters and receivers. This paper presents the effectiveness of calibration circuit for massive MIMO transmission by the testbed which implements the calibration circuit, when considering the interference signal.

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Wideband DOA Estimation Technique for Correlated Sources 招待査読

Hiroyoshi Yamada, Satoshi Shirai, Yoshio Yamaguchi

2014 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP) 27 - 28 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, researches on the wideband wireless system becomes important increasingly due to growth of the requirements on the high-speed broadband communications. Direction of arrival estimation of such a wideband sources with array also important for radio propagation estimation and/or surveillance. DOA estimation of wideband sources is one of the difficult problem because suitable element separation of the array essentially determined by the wavelength of the wave(s). In this report, we propose a new wideband DOA estimation technique that is available depending on the signal correlations.

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Velocity and Direction Estimation by Ocean Surface Current Radar Using Khatri-Rao Product Transform 査読

Takuya Ryukawa, Hiroyoshi Yamada, Yoshio Yamaguchi, Keizo Hirano, Hiroyuki Ito

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 36 - 37 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Ocean surface current radar has attracted attention as a system which can be observed ocean phenomenon effectively. In this report, we evaluate the aperture enhancement effect by applying the Khatri-Rao (KR) product array to the Doppler frequency and angular resolution. Since Doppler frequency represents surface current velocity, resolution enhancement leads to estimation accuracy improvement of the velocity. In this paper, we apply the KR product to actual data set of the ocean surface current radar, and estimated surface current velocity.

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Estimation of Soil Moisture Content and Surface Roughness Using Oh Model and Scattering Power Decomposition 査読

Hiroto Abe, Yoshio Yamaguchi, Hiroyoshi Yamada, Yi Cui

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 32 - 33 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Soil moisture content is an essential parameter in agriculture and hydrological processes. Using remote sensing, we can measure soil moisture content in real time over wide area. Oh model is one of the important models that characterize the scattering properties of the soil, and it can be reliably used to estimate the soil moisture content and surface roughness of the bare soil. However, the estimation accuracy of the Oh model decreases under the influence of vegetation. Therefore, in this paper, we propose a modified method which first extracts the scattering component of the soil surface by using scattering power decomposition, and then applies Oh model for soil moisture and roughness estimation. In the experiment, we report the results on the measured data over a field and demonstrate the effectiveness of the proposed approach.

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MIMO Doppler Radar Using Khatri-Rao Product Virtual Array for Human Location Estimation 査読

Yosuke Wakamatsu, Hiroyoshi Yamada, Yoshio Yamaguchi

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 30 - 31 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

MIMO radar and Khatri-Rao (KR) product virtual array are the methods for increasing angular resolution of the array radar. The KR product is not suited to radar because KR product needs data property of uncorrelated wave incidence. However, when we extract responses of moving targets having different Doppler frequencies by Doppler filtering, the KR product array works almost properly because their correlation become low. In this report, we show the availability of the MIMO radar with the KR product virtual array for indoor location estimation by experiment.

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Effectiveness of Implicit Beamforming Using Calibration Technique in Massive MIMO System 査読

Kentaro Nishimori, Takefumi Hiraguri, Toshiyuki Ogawa, Hiroyoshi Yamada

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 117 - 118 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper describes the effectiveness of implicit beamforming which enables the transmission without the channel state information (CSI) feedback in massive MIMO system. First, we explain the CSI feedback scheme from the terminal stations to base station gives a very large overhead. The calibration technique, which compensate the difference of complex amplitudes between transmitters and receivers for the implicit beamforming, is next introduced. Finally, the throughput by the IEEE802.11ac based massive MIMO transmission with and without CSI feedback is clarified when considering Medium Access Control efficiency.

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Performance Verification of Polarimetric Change Detector Based on Four-Component-Decomposition with PiSAR-2 Data 査読

Kazutomo Yamamoto, Yoshio Yamaguchi, Hiroyoshi Yamada, Gulab Singh

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 133 - 134 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Several techniques for detecting the temporal changes in satellite polarimetric synthetic aperture radar (POLSAR) imagery, called as the polarimetric change detector (PCD), are developed. The PCD would be able to detect areas in the scene for which the observed polarimetric characteristics noticed a change between the two acquisitions. So these techniques have one of the most important applications to understand the evolution of our planet. The X-band very high-resolution polarimetric and interferometric airborne synthetic aperture radar (PiSAR-2) system has been developed by National Institute of Information and Communications Technology (NICT). The more accurate land monitoring is possible from this system. This paper introduces the result of several PCD using multi-temporal Pi-SAR2 polarimetric data with the reference of ground truth data.

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Study on Calibration of the Array Antenna Using a Web Camera 査読

Yu Ishiyama, Hiroyoshi Yamada, Yi Cui, Yoshio Yamaguchi

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 183 - 184 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, the direction-of-arrival (DOA) estimation using an array antenna has been studied extensively. Accordingly, array calibration method has also become an important topic. Conventional data acquisition methods often require a positioner or an azimuth table to make sources of known DOAs for premeasurement of array calibration in a radio anechoic chamber. However, such a measurement is both time-consuming and expensive. In this paper, we propose a simple data acquisition method for array calibration using a Web camera and show its effectiveness by experiments. Additionally, we also report a simulation study to confirm the relationship between the distance from transmitter (Tx) to receiver (Rx) and the array length.

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Human Motion Estimation Using Range-Doppler Response 査読

Shinya Fukushima, Hiroyoshi Yamada, Hirokazu Kobayashi, Yoshio Yamaguchi

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 205 - 206 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Sensing technology using radio wave has been attracting attention for various applications such as office/home security and surveillance. Classification of human motion has been extensively studied in these applications. They often utilize Doppler frequency characteristic occurred by human motion. In this paper, range-Doppler distributions by human motion are studied. We show range-Doppler signatures of six motions in this paper, and evaluate the difference of the motions by correlation. We demonstrated experimentally that the motion difference can be discriminated by the range-Doppler correlation and can be enhanced by the elimination filter of DC Doppler components.

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