Faculty Profiles - IJIMA Hiroshi

Published Papers - IJIMA Hiroshi

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陶器によるディープラーニング教材の開発 : 確率的勾配降下法による最適化の可視化—Development of Teaching Materials for Deep Learning by Making Ceramic Artworks : Visualization of Optimization by Stochastic Gradient Descent

井嶋博

和歌山大学教育学部紀要. 自然科学 ( 和歌山大学教育学部 ) 74 1 - 7 2024.02

2016年の中央教育審議会答申を受けて改訂された新学習指導要領では、高等学校情報科の共通必修科目「情報Ⅰ」および発展選択科目「情報Ⅱ」が設置され、2022年度から実施されている。これらの科目にはデータサイエンスが学習内容に加わり、その一分野である機械学習を扱った教科書が多くを占めている。機械学習は様々なアルゴリズムがあり、現在も研究されている分野で、教科書ではその仕組みの概要をつかむことに重点を置いている。機械学習の中でも近年急速に発展してきた技術であるディープラーニングを取り上げている教科書も多くあるが、その仕組みを視覚的に理解できるような教材はほとんど開発されていない。本研究では、ディープラーニングの要となるアルゴリズムの一つである確率的勾配法を視覚的に理解するため、陶器による教材を制作したので報告する。

Fluid force identification acting on snake-like robots swimming in viscous fluids

A. Yamano, K. Shimizu, M. Chiba, H. Ijima

Journal of Fluids and Structures ( Elsevier BV ) 106 103351 - 103351 2021.10 [Refereed]

Influence of the aspect ratio of the sheet for an electric generator utilizing the rotation of a flapping sheet

Akio YAMANO, Hiroshi IJIMA, Atsuhiko SHINTANI, Chihiro NAKAGAWA, Tomohiro ITO

Mechanical Engineering Journal ( Japan Society of Mechanical Engineers ) 8 ( 1 ) 20 - 00459 2021 [Refereed]

Fundamental Studies on Robot and Robotic Vision in Paddy Field for Removing Egg Mass of Apple Snails

井嶋博, 山口真範

和歌山大学教育学部紀要. 自然科学 = Bulletin of the Faculty of Education, Wakayama University. 和歌山大学教育学部紀要委員会編 ( 和歌山大学教育学部 ) 70 25 - 27 2020.02

現在、日本の農業は後継者不足や従事者の高齢化、また都市圏均衡を中心とした兼業農家の増加で、十分に農作業に時間を割ける従事者が減少している。このような問題に対して、農作業の機械化、環境に強い品種への改良、さらには新たな農薬や肥料の開発が進められてきた。一方、害虫除去や雑草の除去作業などの手作業は依然必要であり、十分農作業が軽減されているとは言えない。特に、温暖な地域の水田で劇的に増加しているスクミリンゴガイ(通称ジャンボタニシ)は、水田で頻繁に繁殖を繰り返し、幼苗を捕食することから、それを定期的に除去する作業が農業従事者にとって大きな負担となっており、現在稲作農家は多様な作業が求められている。著者らは、このような稲作における手作業を代替するための手法の一つとして、稲の育成初期に水田を巡回し育成環境を保全するロボットの研究開発を進めることとした。手始めに本論文では、水田を巡回させるロボット開発の見通しと問題点を整理し、また、ロボットに搭載するための映像センサの開発の一つとして、水田中の映像から、有害となるジャンボタニシの卵塊を検出した結果について報告する。

Extraction and Analysis of Elements Included in Egg Mass of Apple Snails

山口真範, 井嶋博

和歌山大学教育学部紀要. 自然科学 = Bulletin of the Faculty of Education, Wakayama University. 和歌山大学教育学部紀要委員会編 ( 和歌山大学教育学部 ) 70 33 - 35 2020.02

Influence of boundary conditions on a flutter-mill

A Yamano, A Shintani, T Ito, C Nakagawa, H Ijima

Journal of Sound and Vibration 478 ( 21 ) 115359 2020 [Refereed]

Essence and Problem of Education in Secondary Technology Education : Based on the Material and Processing

嶋本光芳, 荒木良一, 井嶋博

和歌山大学教育学部紀要. 教育科学 = Bulletin of the Faculty of Education, Wakayama University. 和歌山大学教育学部紀要委員会編 ( 和歌山大学教育学部 ) 68 ( 2 ) 57 - 60 2018.02

Feasibility of Cross-Curricular Energy Education Around Technology Education

井嶋博, 嶋本光芳, 荒木良一

和歌山大学教育学部紀要. 教育科学 = Bulletin of the Faculty of Education, Wakayama University. 和歌山大学教育学部紀要委員会編 ( 和歌山大学教育学部 ) 68 ( 2 ) 61 - 63 2018.02

エネルギーは我々の生活において欠かせないもののひとつであり、現代社会においては、その資源や用途は多様で、利用方法は高度化されてきている。このようなことから新学習指導要領ではエネルギー教育を環境教育の一つに位置付け、様々な学年で複数の教科の中で取り扱われるようになっている。本稿では各教科、学年におけるエネルギー教育の目的と意義を確認し、中学校技術科における教育分野の一つである「エネルギーの変換と利用」を中心とした教科を横断するエネルギー教育の可能性や問題点について述べる。

Report of Maize Cultivation in Laboratory Farm Fields for Living Environmental Studies

荒木良一, 小林匡輔, 梶村麻紀子, 井嶋博

和歌山大学教育学部紀要. 自然科学 = Bulletin of the Faculty of Education, Wakayama University. 和歌山大学教育学部紀要委員会編 ( 和歌山大学教育学部 ) 68 ( 1 ) 251 - 254 2018.01

Essence and Problem of Technical Art in Secondary School Education : Based on the Culture of Living Organisms

荒木良一, 嶋本光芳, 井嶋博

和歌山大学教育学部紀要. 自然科学 = Bulletin of the Faculty of Education, Wakayama University. 和歌山大学教育学部紀要委員会編 ( 和歌山大学教育学部 ) 68 ( 1 ) 247 - 250 2018.01

技術分野の生物育成分野では生育技術と育成技術に関する内容を扱っている。本稿では生物育成分野の中の植物の栽培における現状について学習指導要領や教科書の内容を整理し、生物育成分野の特徴や課題について考察する。さらに、技術分野が基礎から応用まで扱っているために学生の技術への関心を誘発する可能性が高いので、広範な知識を必要とする技術分野教員をサポートする仕組みが必要であることを指摘した。加えて附属農場で行われた実習についても考察した。

Basic study of the adaptive control for the swimming robot using self-excited oscillation

YAMANO Akio, IJIMA Hiroshi

Transactions of the JSME (in Japanese) ( The Japan Society of Mechanical Engineers ) 84 ( 864 ) 18 - 00054-18-00054 2018 [Refereed]

<p>Some organisms using undulatory locomotion show the transition of the swimming frequency and the wavelength of the undulation. This transition of swimming behavior is achieved by sensory feedback, and may have the role to cope with the environmental change. Especially, one of the nematode: <i>Caenorhabditis elegans</i> can modulate its frequency from approximately 0.3 to 2 Hz, and vary the wavelength of undulating body from less than a single body length to almost twice the body length. With this modulation, <i>C. elegans</i> achieves the movement under the conditions from in water to on the surface of an agar. Inspired by this finding, we propose the adaptive control for the multilink swimming robot because the environmental change demands a mobile robot the change of the pattern of the locomotion. Proposed adaptive control employs the sensory feedback from joint angles to inputs of actuators at joints to generate the self-excited oscillation. At first, we construct the multilink model in fluid with sensory feedback. After that, we construct the linearized model to obtain the relationship among the external resistive force, parameters of the multilink model and the swimming frequency by using the eigenvalue analysis. We confirm whether the proposed adaptive control simulates the modulation of undulation like <i>C. elegans</i>. Moreover, we specify parameters of the multilink model which are related to the frequency and wavelength of undulation significantly.</p>

Basic Study of Electric Generator utilizing Sheet Flutter

YAMANO Akio, IJIMA Hiroshi, SHINTANI Atsuhiko, ITO Tomohiro, NAKAGAWA Chihiro

The Proceedings of the Dynamics & Design Conference ( The Japan Society of Mechanical Engineers ) 2018 ( 0 ) 412 - 412 2018 [Refereed]

<p>This paper reports numerical simulations of the energy harvester utilizing the flutter phenomenon of a flexible sheet. Especially, we focus on the energy harvester that an electric generator is at the leading edge of a flexible sheet, which is proposed by a preceding study and a simpler device than conventional power generators using flutter. We employ the simple numerical model which is modeled by the finite element method with Absolute Nodal Coordinate Formulation: ANCF and Unsteady Vortex Lattice Method: UVLM to design this energy harvester easily. The equation of motion for a flexible sheet has the Kelvin-Voigt-type material damping and the rotational damping at the leading edge of a sheet to emulate the effect of the coupling between a sheet and the energy harvesting circuit. This model was verified by comparing among experimental results and numerical results obtained by CFD analysis. After that, we searched the appropriate damping coefficient which corresponds to the load of a generator circuit to achieve high harvesting efficiency by the proposed model. As a result, we confirmed that the power obtained from fluid by a weak rotational damper decreases as increase of material damping when inlet flow velocity is large, and increases as increase of material damping when inlet flow velocity is small.</p>

Verification of 2D Gaussian Model of Concentration on TLC Plate for Image-Based Quantification of Carbohydrates

H. Ijima, M. Yamaguchi, H. Nakasuji, A. Yamano

Proc. of the 2nd International Conference on Applied Physics, System Science and Computers (APSAC2017) 1 331 - 336 2017.09 [Refereed]

Practice of Learning Each Other Learn in Technology and Home Economics : By Incorporating the 'Learning Community'

嶋本光芳, 井嶋博, 石塚亙

和歌山大学教育学部紀要. 教育科学 ( 和歌山大学教育学部 ) 67 ( 67 ) 167 - 171 2017.02

Essence of Physics at Secondary School Science Education

顧萍, 井嶋博, 石塚亙, 木曽田賢治, 富田晃彦

和歌山大学教育学部紀要. 教育科学 = Bulletin of the Faculty of Education, Wakayama University. 和歌山大学教育学部紀要委員会編 ( 和歌山大学教育学部 ) 67 101 - 104 2017.02

Quantification of Scanning Image for Spot Test Using TLC plate Compensating Lack of Spot Overlaps

H. Ijima, M. Yamaguchi, H. Nakasuji

Proc. SICE Annual Conference 2016 (SICE2016) 940 - 943 2016.09 [Refereed]

Technology Education vied from Safety Aspects : Concerning about Processing Pipes with Lathes

Ijima Hiroshi, Teramoto Tougo, Ishizuka Wataru

和歌山大学教育学部紀要. 教育科学 ( 和歌山大学教育学部 ) 66 59 - 62 2016.02

エクセルVBAによるパワーポイントフラッシュカードの作成

井嶋博

学芸 ( 和歌山大学学芸学会 ) 62 135 - 140 2016 [Refereed]

Quantification of Carbohydrate Based on Scan Image Analysis for TLC Technique Compensating Lack of Spot Overlaps

Hiroshi Ijima, Masanori Yamaguchi

2016 IEEE INTERNATIONAL CONFERENCE ON IMAGING SYSTEMS AND TECHNIQUES (IST) ( IEEE ) 2016 ( IST ) 515 - 519 2016 [Refereed]

In this paper, a quantification method of the carbohydrate is proposed for samples of spot tests using the thin-layer chromatography (TLC) based on the scanned image analysis compensating lack of overlap between each spot. The color density of image data is modeled by 2-dimensional Gaussian function. Parameters in the Gaussian function are estimated by calculating marginal distribution and using least squares (LS) method. Sample image of the spots on the TLC plate are quantified as calculating the volume of Gaussian function. A numerical example is then carried out for quantifying the glucose which is an important and commonly unit of the carbohydrate. The efficiency of our method is pointed out comparing with two non-compensated methods. In addition, in order to investigate the performance of proposed method, calibrated values are also compared with results using the high performance liquid chromatography (HPLC).

Similarity Test of Base Sequence Including Simple Sequence Repeat : Feature Extraction in Spectral Domain

井嶋博, 南山泰宏, 来山顕久

和歌山大学教育学部紀要. 自然科学 = Bulletin of the Faculty of Education, Wakayama University. 和歌山大学教育学部紀要委員会編 ( 和歌山大学教育学部 ) 65 15 - 19 2015.02

Iterative approach to estimate the parameters of a TVAR process corrupted by a MA noise

Hiroshi Ijima, Roberto Diversi, Eric Grivel

European Signal Processing Conference ( European Signal Processing Conference, EUSIPCO ) 456 - 460 2014.11

A great deal of interest has been paid to the time-varying autoregressive (TVAR) parameter tracking, but few papers deal with this issue when noisy observations are available. Recently, this problem was addressed for a TVAR process disturbed by an additive zero-mean white noise, by using deterministic regression methods. In this paper, we focus our attention on the case of an additive colored measurement noise modeled by a moving average process. More particularly, we propose to estimate the TVAR parameters by using a variant of the improved least-squares (ILS) methods, initially introduced by Zheng to estimate the AR parameters from a signal embedded in a white noise. Simulation studies illustrate the advantages and the limits of the approach.

ITERATIVE APPROACH TO ESTIMATE THE PARAMETERS OF A TVAR PROCESS CORRUPTED BY A MA NOISE

Hiroshi Ijima, Roberto Diversi, Eric Grivel

2014 PROCEEDINGS OF THE 22ND EUROPEAN SIGNAL PROCESSING CONFERENCE (EUSIPCO) ( IEEE ) 456 - 460 2014 [Refereed]

A great deal of interest has been paid to the time-varying autoregressive (TVAR) parameter tracking, but few papers deal with this issue when noisy observations are available. Recently, this problem was addressed for a TVAR process disturbed by an additive zero-mean white noise, by using deterministic regression methods. In this paper, we focus our attention on the case of an additive colored measurement noise modeled by a moving average process. More particularly, we propose to estimate the TVAR parameters by using a variant of the improved least-squares (ILS) methods, initially introduced by Zheng to estimate the AR parameters from a signal embedded in a white noise. Simulation studies illustrate the advantages and the limits of the approach.

PREDICTION ERROR METHOD TO ESTIMATE THE AR PARAMETERS WHEN THE AR PROCESS IS DISTURBED BY A COLORED NOISE

Roberto Diversi, Hiroshi Ijima, Eric Grivel

2013 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP) ( IEEE ) 2013 Vol.9 6143 - 6147 2013 [Refereed]

Estimating the autoregressive parameters from noisy observations has been addressed by various authors for the last decades. Although several on-line or off-line approaches have been proposed when the additive noise is white, few papers deal with the additive moving average noise. In this paper, we suggest estimating the model parameters by using the prediction error method. Despite its high computational cost, the method has the advantage of being efficient in the Gaussian case. A comparative study with existing methods is then carried out and points out the efficiency of our approach especially when the number of samples is small.

Deterministic regression methods for unbiased estimation of time-varying autoregressive parameters from noisy observations

Hiroshi Ijima, Eric Grivel

SIGNAL PROCESSING ( ELSEVIER SCIENCE BV ) 92 ( 4 ) 857 - 871 2012.04 [Refereed]

A great deal of interest has been paid to autoregressive parameter estimation in the noise-free case or when the observation data are disturbed by random noise. Tracking time-varying autoregressive (TVAR) parameters has been also discussed, but few papers deal with this issue when there is an additive zero-mean white Gaussian measurement noise. In this paper, one considers deterministic regression methods (or evolutive methods) where the WAR parameters are assumed to be weighted combinations of basis functions. However, the additive white measurement noise leads to a weight-estimation bias when standard least squares methods are used. Therefore, we propose two alternative blind off-line methods that allow both the variance of the additive noise and the weights to be estimated. The first one is based on the errors-in-variable issue whereas the second consists in viewing the estimation issue as a generalized eigenvalue problem. A comparative study with other existing methods confirms the effectiveness of the proposed methods. (C) 2011 Elsevier B.V. All rights reserved.

Estimation of multichannel TVAR parameters from noisy observations based on an evolutive method

Hiroshi Ijima, Eric Grivel

European Signal Processing Conference 990 - 994 2011

The multichannel time-varying autoregressive (M-TVAR) model is used in various applications such as radar processing, mobile communications and econometric time series. In that case, the M-TVAR parameter matrices are usually estimated by extending the evolutive method, initially proposed by Grenier in the 80ies for the scalar case. In that case, the time-varying coefficients of each matrix are expressed as weighted combinations of pre-defined basis functions. However, the estimation of the M-TVAR parameter matrices from noisy observations is a still key issue to be addressed. In this paper, we propose an effective evolutive method to estimate M-TVAR matrices from noisy observations. We suggest viewing the weight estimation from noisy observations as an errors-invariables issue. Despite its high computational cost, the approach has the advantage of also providing the covariance matrix of both the driving process and the additive noise. Simulation results point out the relevance of the approach. © 2011 EURASIP.

EVOLUTIVE METHOD BASED ON A GENERALIZED EIGENVALUE DECOMPOSITION TO ESTIMATE TIME VARYING AUTOREGRESSIVE PARAMETERS FROM NOISY OBSERVATIONS

Hiroshi Ijima, Julien Petitjean, Eric Grivel

2011 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING ( IEEE ) 2011 Vol.5 3808 - 3811 2011 [Refereed]

A great deal of interest has been paid to the estimation of time-varying autoregressive (TVAR) parameters. However, when the observations are disturbed by an additive white measurement noise, using standard least squares methods leads to a weight-estimation bias. In this paper, we propose to jointly estimate the TVAR parameters and the measurement-noise variance from noisy observations by means of a generalized eigenvalue decomposition. It extends to the TVAR case an off-line method that was initially proposed for AR parameter estimation from noisy observations. A comparative study is then carried out with existing methods such as the recursive errors-in-variable approach and Kalman based algorithms.

ESTIMATION OF MULTICHANNEL TVAR PARAMETERS FROM NOISY OBSERVATIONS BASED ON AN EVOLUTIVE METHOD

Hiroshi Ijima, Eric Grivel

19TH EUROPEAN SIGNAL PROCESSING CONFERENCE (EUSIPCO-2011) ( EUROPEAN ASSOC SIGNAL SPEECH & IMAGE PROCESSING-EURASIP ) 990 - 994 2011 [Refereed]

The multichannel time-varying autoregressive (M-TVAR) model is used in various applications such as radar processing, mobile communications and econometric time series. In that case, the M-TVAR parameter matrices are usually estimated by extending the evolutive method, initially proposed by Grenier in the 80ies for the scalar case. In that case, the time-varying coefficients of each matrix are expressed as weighted combinations of pre-defined basis functions. However, the estimation of the M-TVAR parameter matrices from noisy observations is a still key issue to be addressed. In this paper, we propose an effective evolutive method to estimate M-TVAR matrices from noisy observations. We suggest viewing the weight estimation from noisy observations as an errors-in variables issue. Despite its high computational cost, the approach has the advantage of also providing the covariance matrix of both the driving process and the additive noise. Simulation results point out the relevance of the approach.

Kalman Filter‐based Detector of Signals in Nonstationary Random Noise

IJIMA Hiroshi, OHSUMI Akira

Proceedings of the ISCIE International Symposium on Stochastic Systems Theory and its Applications (Institute of Systems, Control and Information Engineers) 40th 210 - 214 2009 [Refereed]

Detection of Signals Corrupted by Nonstationary Random Noise via Kalman Filter-based Stationarization Approach

Ijima Hiroshi, Ohsumi Akira

Proceedings of the Annual Conference of the Institute of Systems, Control and Information Engineers ( The Institute of Systems, Control and Information Engineers ) 8 ( 0 ) 324 - 324 2008 [Refereed]

本論文では，非定常不規則雑音に埋もれた信号を検出する新しい手法を提案する．従来，信号検出問題においては，雑音は数学的に取扱いが容易であることからその統計的性質が時間的に変化しない定常確率過程として取り扱われてきた．しかし，実際に観測されるデータには，例えば海上や海底における潮力などの影響によって非定常なものが多く存在する．このような非定常雑音中の信号検出問題に対して，本論文では信号は時間的に局所的に存在し，雑音の非定常性は緩やかに変化するものと仮定して，観測雑音を時変係数を持つARMAモデルで記述できるとする．このモデルパラメータをカルマンフィルタにより推定し非定常観測データを定常とみなせる観測データに変換する手法を提案し，その有効性を数値シミュレーションにより確認する．この手法により，非定常雑音が観測データに介在する問題は，従来の定常雑音に埋もれた信号の検出問題に帰着できる．

Detection of signals in nonstationary random noise via stationarization of data incorporated with Kalman filter

Hiroshi Ijima, Yukinori Yamashita, Akira Ohsumi

2007 IEEE INTERNATIONAL SYMPOSIUM ON SIGNAL PROCESSING AND INFORMATION TECHNOLOGY, VOLS 1-3 ( IEEE ) 562 - + 2007 [Refereed]

ESTIMATION OF MOTION PARAMETERS OF MOVING TARGET USING WIGNER DISTRIBUTION

Hiroshi Ijima, Azusa Matsuoka, Tetsuya Nakajima, Akira Ohsumi

ICSPC: 2007 IEEE INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATIONS, VOLS 1-3, PROCEEDINGS ( IEEE ) 688 - + 2007 [Refereed]

A method of detection of signals corrupted by nonstationary random noise via stationarization of the data

Hiroshi Ijima, Akira Ohsumi, Ryo Okui

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE ( SCRIPTA TECHNICA-JOHN WILEY & SONS ) 90 ( 8 ) 29 - 38 2007 [Refereed]

This paper proposes a method for detecting a signal embedded in nonstationary noise. In most past studies of the signal detection problem, random noise is considered as a stationary stochastic process, since it is mathematically easy to handle. However, the noise observed in practice contains many nonstationary elements with time-varying (evolutionary) statistical properties. In this study, observational noise is modeled as a probability density function with slowly evolving parameters. Then, based on the evolving spectral representation, the nonstationary observation data are transformed to a stationary process. A new method is proposed as follows. It is assumed that nonstationarity remains in the stationarized observation data in the interval containing the signal, due to the effect of the signal. Then the signal is detected by testing for stationarity. In the proposed method, Priestley's evolutionary spectrum is used in the spectral representation of the nonstationary stochastic process, and the method of Okabe and colleagues based on the KM2O-Langevin equation is used for the stationarity test. The effectiveness of the proposed method is verified by a simulation experiment. (C) 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(8): 29-38, 2007; Published online in Wiley InterScience (www.interscience.wiley.com).

A Method of Detection of Signals Corrupted by Nonstationary Random Noise via Stationarization of the Data

IJIMA Hiroshi, OHSUMI Akira, OKUI Ryo

The IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Japanese edition) A ( The Institute of Electronics, Information and Communication Engineers ) 89 ( 6 ) 535 - 543 2006.06 [Refereed]

本研究は非定常雑音に埋もれた信号の検出に対する一つの手法を提案したものである.従来の多くの信号検出問題においては,不規則雑音は数学的取扱いが容易であることから定常確率過程として取り扱われてきた.しかし,実際観測される雑音には時間とともに統計的性質が変化する非定常雑音が多く存在する.本研究では,観測雑音を緩やかに変化するパラメータをもつ確率密度関数としてモデル化し,その時間変化するスペクトル表現から非定常な観測データを定常過程に変換する.このとき,信号が存在する区間においてはその信号の影響により定常化された観測データに非定常性が残存すると考え,その定常性の検定により信号を検出するという新しい手法を提案する.この手法において,非定常確率過程のスペクトル表現にはPriestleyの時変スペクトル,定常性の検定には岡部らによるKM_2O-ランジュヴァン方程式に基づいた手法を用いる.提案した手法の有効性をシミュレーション実験により確認している.

Time-delay estimation of signals in nonstationary random noise via stationarization and Wigner distribution-based approach.

Hiroshi Ijima, Akira Ohsumi, Satoshi Yamaguchi

14th European Signal Processing Conference, EUSIPCO 2006, Florence, Italy, September 4-8, 2006 ( IEEE ) 1 - 5 2006 [Refereed]

Detection of signals in nonstationary random noise via stationarization and stationarity test

Hiroshi Ijima, Ryo Okui, Akira Ohsumi

2005 IEEE/SP 13th Workshop on Statistical Signal Processing (SSP), Vols 1 and 2 ( IEEE ) 543 - 546 2005 [Refereed]

Motion parameters estimation by new propagation approach and time-frequency representations

Djurovic, I, S Stankovic, A Ohsumi, H Ijima

SIGNAL PROCESSING-IMAGE COMMUNICATION ( ELSEVIER SCIENCE BV ) 19 ( 8 ) 755 - 770 2004.09 [Refereed]

Estimation of time-varying motion parameters of moving objects is considered. The motion parameters are mapped into the instantaneous frequency (IF) of a frequency modulated signal. The IF estimation is obtained by using the Wigner distribution. Generalization in the case of multiple objects and reduced interference distributions is given. A new propagation approach is proposed for joint estimation of velocity and position of objects in a video-sequence. This approach produces better accuracy than the variable mu-propagation-based one. (C) 2004 Elsevier B.V. All rights reserved.

Parameter Estimation of Chirp Signals in Random Noise Using Wigner Distribution

Proc. 47th IEEE International Midwest Symposium on Circuits and Systems (MWSCAS 2004) vol.Ⅱ 177 - 180 2004.07 [Refereed]

Parameter Estimation for FM-CW Radar Signals in Random Noise Using Wigner Distribution

Ijima Hiroshi, Ohsumi Akira

Proceedings of the Annual Conference of the Institute of Systems, Control and Information Engineers ( The Institute of Systems, Control and Information Engineers ) 4 ( 0 ) 32 - 32 2004 [Refereed]

Estimation of the parameters and angle-of-arrival of wideband signals on sensor arrays based on the phase differentiation algorithm

Djurovic, I, A Ohsumi, H Ijima

OCEANS '04 MTS/IEEE TECHNO-OCEAN '04, VOLS 1- 2, CONFERENCE PROCEEDINGS, VOLS. 1-4 ( IEEE ) Vol.2, pp.631- 634 631 - 634 2004 [Refereed]

Phase differentiation algorithms represent a powerful tool for estimation of polynomial phase wideband signals parameters. Here, they are used for development of a suboptimal algorithm for estimation of parameters of wideband signals received on a linear sensor array. The proposed suboptimal method is considered in the case of linear FM signal and compared with the chirp-beamformer approach. The proposed approach behaves slightly worse than the later. However, the chirp beamformer requires a 3D search procedure (or genetic algorithms) that is very consuming comparing to the ID search for chirp-rate parameter and 2D search for carrier frequency and angle-of-arrival estimation. This approach can be generalized to the polynomial phase signals of higher order.

Parameter Estimation of Signals in Random Noise : An Approach Using Pseudo-Wigner Distribution

IJIMA Hiroshi, OHSUMI Akira, DJUROVIC Igor, SATO Hideaki, OKURA Hiroyuki

The Transactions of the Institute of Electronics, Information and Communication Engineers A ( The Institute of Electronics, Information and Communication Engineers ) 86 ( 11 ) 1158 - 1169 2003.11 [Refereed]

不規則雑音に埋もれた信号の検定・推定問題は,音声,通信,計測など工学の分野だけでなく医療,自然信号など様々な分野で応用されている.本論文では不規則雑音に埋もれて受信される信号の遅れ時間と伸縮パラメータを同時に推定する新しい手法を提案する.信号の伸縮が受信された信号の周波数に反映されるということに着目して,時間-周波数解析の有力な手法の一つである擬似ウィグナー分布を用い,その時間-周波数領域における確率場に対して尤(ゆう)度関数を求め,それを最大にするアルゴリズムを導出することによってこれらの未知パラメータを推定する.更に,その有効性を数値シミュレーションによって示す.

Maximum likelihood estimation of time-delay of ultrasonic signals based on Wigner distribution

H Ijima, A Ohsumi

Proc. SICE 2003 ANNUAL CONFERENCE ( IEEE ) pp.1774 -1778 2545 - 2549 2003 [Refereed]

Recursive realization of the robust STFT

Djurovic, I, LA Stankovic, A Ohsumi, H Ijima

SEVENTH INTERNATIONAL SYMPOSIUM ON SIGNAL PROCESSING AND ITS APPLICATIONS, VOL 1, PROCEEDINGS ( IEEE ) vol.1, pp.157-160 157 - 160 2003 [Refereed]

An efficient procedure is proposed for the realization of robust short-time Fourier transform (STFT) based on the recursive realization of the standard STFT. In the initial stage it uses the robust STFT calculated by iterative or sorting procedures and, after that, the recursive relation is applied. Basic difference from: the standard STFT realization is in limiting samples in the next instants, since they can be corrupted by an impulse noise. It results in a numerically efficient form of the STFT, keeping robustness to the impulse noise influence.

Instantaneous frequency estimation by using Wigner distribution and Viterbi algorithm

L Stankovic, Djurovic, I, A Ohsumi, H Ijima

2003 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, VOL VI, PROCEEDINGS ( IEEE ) vol.Ⅵ, pp.121-124 121 - 124 2003 [Refereed]

Estimation of line parameters using SLIDE algorithm and TF representations

Djurovic, I, S Stankovic, A Ohsumi, H Ijima

ICES 2002: 9TH IEEE INTERNATIONAL CONFERENCE ON ELECTRONICS, CIRCUITS AND SYSTEMS, VOLS I-111, CONFERENCE PROCEEDINGS ( IEEE ) vol.3, pp.1067-1070 1067 - 1070 2002 [Refereed]

Maximum likelihood estimation for signal parameters using pseudo-Wigner distribution

H Ijima, A Ohsumi, H Sato, Djurovic, I

SICE 2002: PROCEEDINGS OF THE 41ST SICE ANNUAL CONFERENCE, VOLS 1-5 ( IEEE ) pp.1598-1603 1464 - 1469 2002 [Refereed]

The enhanced detector of noisy signals using pseudo-Wigner distribution

IJIMA H.

Proc. IASTED Int. Conf. Signal Processing, Pattern Recognition and Applications, Rhodes, Greese, July, 2001 pp.95-100 95 - 100 2001 [Refereed]

On a Signal Detector using Wavelet-based Quadratic Time-Frequency Distribution

Proc. 5th WSES Multiconference on Circuits, Systems, Communications & Computers (CSCC 2001) pp.42-47 2001 [Refereed]

High resolution detector for signals in random noise using wavelet-based Wigner distribution

A Ohsumi, H Ijima, T Sodeoka

2000 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, PROCEEDINGS, VOLS I-VI ( IEEE ) vol.I, pp.596-599 596 - 599 2000 [Refereed]

Online detection of pulse sequence in random noise using a wavelet

A Ohsumi, H Ijima, T Kuroishi

IEEE TRANSACTIONS ON SIGNAL PROCESSING ( IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC ) 47 ( 9 ) 2526 - 2531 1999.09 [Refereed]

On-Line Detection of a Pulse Sequence in Random Noise Using a Wavelet

OHSUMI Akira, KUROISHI Tomoki, IJIMA Hiroshi

計測自動制御学会論文集 ( 計測自動制御学会 ) 33 ( 7 ) 665 - 673 1997.07 [Refereed]

On-Line Detection of a Pulse Sequence in Random Noise Using a Wavelet

OHSUMI Akira, KUROISHI Tomoki, IJIMA Hiroshi

Transactions of the Society of Instrument and Control Engineers ( The Society of Instrument and Control Engineers ) 33 ( 7 ) 665 - 673 1997 [Refereed]

Performance Analysis of the On-line Signal Detectors Using a Wavelet

OHSUMI Akira, IJIMA Hiroshi

インテリジェント・システム・シンポジウム講演論文集 = FAN Symposium : fuzzy, artificial intelligence, neural networks and computational intelligence 6 400 - 403 1996.10 [Refereed]

Wavelet-Based On-line Detectors for Pulse Signals in Random Noise and Their Performance Analysis

Proc. World Automation Congress (WAC’98) pp.265-272 1985 [Refereed]

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