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Aspect based sentiment analysis using multi-criteria decision-making and deep learning under COVID-19 pandemic in India
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作者 Rakesh Dutta Nilanjana Das +1 位作者 Mukta Majumder Biswapati Jana 《CAAI Transactions on Intelligence Technology》 SCIE EI 2023年第1期219-234,共16页
The COVID-19 pandemic has a significant impact on the global economy and health.While the pandemic continues to cause casualties in millions,many countries have gone under lockdown.During this period,people have to st... The COVID-19 pandemic has a significant impact on the global economy and health.While the pandemic continues to cause casualties in millions,many countries have gone under lockdown.During this period,people have to stay within walls and become more addicted towards social networks.They express their emotions and sympathy via these online platforms.Thus,popular social media(Twitter and Facebook)have become rich sources of information for Opinion Mining and Sentiment Analysis on COVID-19-related issues.We have used Aspect Based Sentiment Analysis to anticipate the polarity of public opinion underlying different aspects from Twitter during lockdown and stepwise unlock phases.The goal of this study is to find the feelings of Indians about the lockdown initiative taken by the Government of India to stop the spread of Coronavirus.India-specific COVID-19 tweets have been annotated,for analysing the sentiment of common public.To classify the Twitter data set a deep learning model has been proposed which has achieved accuracies of 82.35%for Lockdown and 83.33%for Unlock data set.The suggested method outperforms many of the contemporary approaches(long shortterm memory,Bi-directional long short-term memory,Gated Recurrent Unit etc.).This study highlights the public sentiment on lockdown and stepwise unlocks,imposed by the Indian Government on various aspects during the Corona outburst. 展开更多
关键词 aspect based sentiment analysis bi-directional gated recurrent unit COVID-19 deep learning k-means clustering multi-criteria decision-making natural language processing
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Optimization of green sand mould system using Taguchi based grey relational analysis 被引量:3
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作者 Srinivasa Rao Pulivarti Anil Kumar Birru 《China Foundry》 SCIE 2018年第2期152-159,共8页
The strength of the mould cavity in sand casting is very much significant to attain high-quality castings. Optimization of green sand process parameters plays a vital role in minimizing casting defects. In the present... The strength of the mould cavity in sand casting is very much significant to attain high-quality castings. Optimization of green sand process parameters plays a vital role in minimizing casting defects. In the present research work, the effect of process parameters such as AFS grain fineness number, water, molasses, bentonite, fly ash, and ramming, and their levels on the resultant mould properties were investigated and optimized using Taguchi based grey relational analysis. The Taguchi L18 orthogonal array and analysis of variance(ANOVA) were used. The quality characteristics viz., green compression strength, permeability, bulk density, mould hardness and shatter index of green sand mould were optimized using grey relational grade, based on the experiments designed using Taguchi's Design of Experiments. ANOVA analysis indicated that water content is the most influential parameter followed by bentonite, and degree of ramming that contributes to the quality characteristics. The results are confirmed by calculating confidence intervals, which lies within the interval limits. Finally, microstructure observations and X-ray diffraction analysis have been performed for the optimal sand parametric combination. Results show that presence of maximum amount of SiO_2, which might be the reason for enhancement of the physical properties of the sand. 展开更多
关键词 green sand BENTONITE fly ash MOLASSES Taguchi based grey relational analysis grain fineness number
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Thermal Analysis of Organic Light Emitting Diodes Based on Basic Heat Transfer Theory 被引量:1
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作者 张稳稳 吴朝新 +3 位作者 刘迎文 董军 严学文 侯洵 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第8期139-143,共5页
We investigate the thermal characteristics of standard organic light-emitting diodes (OLEDs) using a simple and clear 1D thermal model based on the basic heat transfer theory. The thermal model can accurately estima... We investigate the thermal characteristics of standard organic light-emitting diodes (OLEDs) using a simple and clear 1D thermal model based on the basic heat transfer theory. The thermal model can accurately estimate the device temperature, which is linearly with electrical input power. The simulation results show that there is almost no temperature gradient within the OLED device working under steady state conditions. Furthermore, thermal analysis simulation results show that the surface properties (convective heat transfer coetficient and surface emissivity) of the substrate or cathode can significantly affect the temperature distribution of the OLED. 展开更多
关键词 OLEDS Thermal analysis of Organic Light Emitting Diodes based on Basic Heat Transfer Theory EML
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QUANTITATIVE ANALYSIS OF VERY WEAK ACID AND BASE BY pH-FIXED TITRATION METHOD
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作者 Gang XU Ping WEI Yu Cheng XIE Xing Dong YU(Jiangsu Institute of Chemical Technology,Changzhou,213016) 《Chinese Chemical Letters》 SCIE CAS CSCD 1990年第1期81-84,共4页
pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant. This me... pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant. This method had been applied to determine phenol,4-aminoantipyrine and glycine,whose ionization constants range from 10^(-10)to 10^(-12).The results were satisfactory. 展开更多
关键词 AATP ACID QUANTITATIVE analysis OF VERY WEAK ACID AND base BY pH-FIXED TITRATION METHOD ACID pH
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Microstructural image based convolutional neural networks for efficient prediction of full-field stress maps in short fiber polymer composites
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作者 S.Gupta T.Mukhopadhyay V.Kushvaha 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第6期58-82,共25页
The increased demand for superior materials has highlighted the need of investigating the mechanical properties of composites to achieve enhanced constitutive relationships.Fiber-reinforced polymer composites have eme... The increased demand for superior materials has highlighted the need of investigating the mechanical properties of composites to achieve enhanced constitutive relationships.Fiber-reinforced polymer composites have emerged as an integral part of materials development with tailored mechanical properties.However,the complexity and heterogeneity of such composites make it considerably more challenging to have precise quantification of properties and attain an optimal design of structures through experimental and computational approaches.In order to avoid the complex,cumbersome,and labor-intensive experimental and numerical modeling approaches,a machine learning(ML)model is proposed here such that it takes the microstructural image as input with a different range of Young’s modulus of carbon fibers and neat epoxy,and obtains output as visualization of the stress component S11(principal stress in the x-direction).For obtaining the training data of the ML model,a short carbon fiberfilled specimen under quasi-static tension is modeled based on 2D Representative Area Element(RAE)using finite element analysis.The composite is inclusive of short carbon fibers with an aspect ratio of 7.5that are infilled in the epoxy systems at various random orientations and positions generated using the Simple Sequential Inhibition(SSI)process.The study reveals that the pix2pix deep learning Convolutional Neural Network(CNN)model is robust enough to predict the stress fields in the composite for a given arrangement of short fibers filled in epoxy over the specified range of Young’s modulus with high accuracy.The CNN model achieves a correlation score of about 0.999 and L2 norm of less than 0.005 for a majority of the samples in the design spectrum,indicating excellent prediction capability.In this paper,we have focused on the stage-wise chronological development of the CNN model with optimized performance for predicting the full-field stress maps of the fiber-reinforced composite specimens.The development of such a robust and efficient algorithm would significantly reduce the amount of time and cost required to study and design new composite materials through the elimination of numerical inputs by direct microstructural images. 展开更多
关键词 Micromechanics of fiber-reinforced composites Machine learning assisted stress prediction Microstructural image-based machine learning CNN based stress analysis
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Residue Based Open-Loop Modal Analysis Method for Detecting LFMR of PMSG-WFs Penetrated Power Systems
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作者 Luonan Qiu Tianhao Wen +1 位作者 Yang Liu Q.H.Wu 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2024年第4期1454-1465,共12页
This paper proposes a residue based open-loop modal analysis method to detect low frequency modal resonance(LFMR),including asymmetric low frequency modal attraction(ALFMA)and asymmetric low frequency modal repulsion(... This paper proposes a residue based open-loop modal analysis method to detect low frequency modal resonance(LFMR),including asymmetric low frequency modal attraction(ALFMA)and asymmetric low frequency modal repulsion(ALFMR),of permanent magnetic synchronous generator based wind farms(PMSG-WFs)penetrated power systems.The formation of ALFMA and ALFMR caused by two open-loop low frequency oscillation(LFO)modes moving close and apart is analyzed in detail.Via predicting the trajectories of closed-loop LFO modes based on calculation of residue of open-loop LFO modes,both ALFMA and ALFMR can be detected.The proposed method can select LFO modes which move to the right half complex plane as control parameters vary.Simulation studies are carried out on a three-machine power system and a four-machine 11-bus power system to verify the properties of the proposed method. 展开更多
关键词 Asymmetric low frequency modal attraction asymmetric low frequency modal repulsion low frequency modal resonance residue based open-loop modal analysis method
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FAULT DIAGNOSIS APPROACH FOR ROLLER BEARINGS BASED ON EMPIRICAL MODE DECOMPOSITION METHOD AND HILBERT TRANSFORM 被引量:14
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作者 YuDejie ChengJunsheng YangYu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2005年第2期267-270,共4页
Based upon empirical mode decomposition (EMD) method and Hilbert spectrum, a method for fault diagnosis of roller bearing is proposed. The orthogonal wavelet bases are used to translate vibration signals of a roller b... Based upon empirical mode decomposition (EMD) method and Hilbert spectrum, a method for fault diagnosis of roller bearing is proposed. The orthogonal wavelet bases are used to translate vibration signals of a roller bearing into time-scale representation, then, an envelope signal can be obtained by envelope spectrum analysis of wavelet coefficients of high scales. By applying EMD method and Hilbert transform to the envelope signal, we can get the local Hilbert marginal spectrum from which the faults in a roller bearing can be diagnosed and fault patterns can be identified. Practical vibration signals measured from roller bearings with out-race faults or inner-race faults are analyzed by the proposed method. The results show that the proposed method is superior to the traditional envelope spectrum method in extracting the fault characteristics of roller bearings. 展开更多
关键词 Roller bearing Empirical mode decomposition(EMD) Hilbert spectrum Local Hilbert marginal spectrum Wavelet bases Envelope analysis
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A coin-tap method of composite materials non-destructive testing based on improved grey clustering 被引量:2
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作者 YU Xiaowen XU Liping +1 位作者 LI Jian WANG Wei 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2021年第1期120-126,共7页
Aiming at the problems of low reliability and complex operation of traditional coin-tap test of composite material,this paper introduces the grey system theory and achieves better performance.The response signals of c... Aiming at the problems of low reliability and complex operation of traditional coin-tap test of composite material,this paper introduces the grey system theory and achieves better performance.The response signals of coin-tap are classified through the grey clustering based on relation analysis,and corresponding improvements are made to the calculation method of the relation degree of nearness.First,the time history of acceleration is taken as the system behavior sequence.The improved correlation calculation method is used to solve the relation degree of nearness between the sequences,and the matrix of degree of grey relation is constructed based on this.Then,the sequence groups are summarized through the matrix,and the response signals of coin-tap are qualitatively classified according to the location of the reference sequence.Finally,the defect detection of composite materials is completed without pre-testing.The test results show that the accuracy of the coin-tap test based on improved grey clustering reaches 100%,which simplifies the operation steps while ensuring the reliability of the coin-tap test results. 展开更多
关键词 non-destructive testing coin-tap test grey clustering based on relation analysis composite material
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Derivation of energy-based base shear force coefficient considering hysteretic behavior and P-delta effects 被引量:2
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作者 Taner Ucar Onur Merter 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2018年第1期149-163,共15页
A modified energy-balance equation accounting for P-delta effects and hysteretic behavior of reinforced concrete members is derived. Reduced hysteretic properties of structural components due to combined stiffness and... A modified energy-balance equation accounting for P-delta effects and hysteretic behavior of reinforced concrete members is derived. Reduced hysteretic properties of structural components due to combined stiffness and strength degradation and pinching effects, and hysteretic damping are taken into account in a simple manner by utilizing plastic energy and seismic input energy modification factors. Having a pre-selected yield mechanism, energy balance of structure in inelastic range is considered. P-delta effects are included in derived equation by adding the external work of gravity loads to the work of equivalent inertia forces and equating the total external work to the modified plastic energy. Earthquake energy input to multi degree of freedom(MDOF) system is approximated by using the modal energy-decomposition. Energybased base shear coefficients are verified by means of both pushover analysis and nonlinear time history(NLTH) analysis of several RC frames having different number of stories. NLTH analyses of frames are performed by using the time histories of ten scaled ground motions compatible with elastic design acceleration spectrum and fulfilling duration/amplitude related requirements of Turkish Seismic Design Code. The observed correlation between energy-based base shear force coefficients and the average base shear force coefficients of NLTH analyses provides a reasonable confidence in estimation of nonlinear base shear force capacity of frames by using the derived equation. 展开更多
关键词 energy-based base shear force coefficient reduced hysteretic behavior P-delta effect pushover analysis nonlinear time history analysis
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Impairment of Continuous Insulin Delivery Therapy and Analysis from Graeco-Latin Square Design Model
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作者 Norou Diawara Ayodeji Demuren Eric Gyuricsko 《Journal of Biosciences and Medicines》 2016年第8期40-51,共12页
The desire to deliver measured amount of insulin continuously to patients with type I diabetes, for glycemic control, has attracted a lot of attention. Continuous subcutaneous insulin infusion has seen some success in... The desire to deliver measured amount of insulin continuously to patients with type I diabetes, for glycemic control, has attracted a lot of attention. Continuous subcutaneous insulin infusion has seen some success in recent years. However, occlusion of insulin delivery may prevent the patient from receiving the prescribed dosage, with adverse consequence. An in vitro study of insulin delivery is performed, using different insulin pumps, insulin analogs and operating conditions. The aim is to identify incidences of occlusion due to bubble formation in the infusion line. A detailed statistical analysis was performed on the data collected to determine any significant differences and deviations in insulin delivery rates that might be due to factors such as: pump type, the set basal flow rate, insulin type, vibration, and possible insulin occlusion due to air bubble formation within the infusion line. Our findings from the Graeco-Latin Square design model show that there are statistical differences due to the devices, and statistical identifiable clusters are used to distinguish the devices. Such hierarchical models used to describe the analyses, include the flow rate, the pump types, and the activity level. 展开更多
关键词 Graeco-Latin Square Design Insulin Delivery Model based Cluster analysis OCCLUSION
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Battle Royale Optimization with Fuzzy Deep Learning for Arabic Sentiment Classification
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作者 Manar Ahmed Hamza Hala J.Alshahrani +3 位作者 Jaber S.Alzahrani Heba Mohsen Mohamed I.Eldesouki Mohammed Rizwanullah 《Computer Systems Science & Engineering》 SCIE EI 2023年第8期2619-2635,共17页
Aspect-Based Sentiment Analysis(ABSA)on Arabic corpus has become an active research topic in recent days.ABSA refers to a fine-grained Sentiment Analysis(SA)task that focuses on the extraction of the conferred aspects... Aspect-Based Sentiment Analysis(ABSA)on Arabic corpus has become an active research topic in recent days.ABSA refers to a fine-grained Sentiment Analysis(SA)task that focuses on the extraction of the conferred aspects and the identification of respective sentiment polarity from the provided text.Most of the prevailing Arabic ABSA techniques heavily depend upon dreary feature-engineering and pre-processing tasks and utilize external sources such as lexicons.In literature,concerning the Arabic language text analysis,the authors made use of regular Machine Learning(ML)techniques that rely on a group of rare sources and tools.These sources were used for processing and analyzing the Arabic language content like lexicons.However,an important challenge in this domain is the unavailability of sufficient and reliable resources.In this background,the current study introduces a new Battle Royale Optimization with Fuzzy Deep Learning for Arabic Aspect Based Sentiment Classification(BROFDL-AASC)technique.The aim of the presented BROFDL-AASC model is to detect and classify the sentiments in the Arabic language.In the presented BROFDL-AASC model,data pre-processing is performed at first to convert the input data into a useful format.Besides,the BROFDL-AASC model includes Discriminative Fuzzy-based Restricted Boltzmann Machine(DFRBM)model for the identification and categorization of sentiments.Furthermore,the BRO algorithm is exploited for optimal fine-tuning of the hyperparameters related to the FBRBM model.This scenario establishes the novelty of current study.The performance of the proposed BROFDL-AASC model was validated and the outcomes demonstrate the supremacy of BROFDL-AASC model over other existing models. 展开更多
关键词 Arabic corpus aspect based sentiment analysis arabic language deep learning battle royale optimization natural language processing
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A united optimum images fusion based on analysis of color distortion 被引量:2
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作者 肖刚 敬忠良 +1 位作者 李建勋 Henry Leung 《Chinese Optics Letters》 SCIE EI CAS CSCD 2004年第3期144-147,共4页
In remote sensing community, IHS (intensity, hue, and saturation) transform is one of the most commonly used fusion algorithm. A study on IHS fusion indicates that the color distortion cannot be avoided. Meanwhile, wa... In remote sensing community, IHS (intensity, hue, and saturation) transform is one of the most commonly used fusion algorithm. A study on IHS fusion indicates that the color distortion cannot be avoided. Meanwhile, wavelet decomposition has a property of frequency division in transform domain. And the statistical property of wavelet coefficient reflects those significant features. So, a united optimal fusion method, which using the statistical property of wavelet decomposition and IHS transform on pixel and 展开更多
关键词 high A united optimum images fusion based on analysis of color distortion IHS RGB
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Wheeze detecting method based on spectrogram entropy analysis 被引量:5
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作者 LI Jiarui HONG Ying 《Chinese Journal of Acoustics》 CSCD 2016年第4期508-515,共8页
In order to eliminate the subjectivity of wheeze diagnosis and improve the accuracy of objective detecting methods,this paper introduces a wheeze detecting method based on spectrogram entropy analysis.This algorithm m... In order to eliminate the subjectivity of wheeze diagnosis and improve the accuracy of objective detecting methods,this paper introduces a wheeze detecting method based on spectrogram entropy analysis.This algorithm mainly comprises three steps which are preprocessing,features extracting and wheeze detecting based on support vector machine(SVM).Herein,the preprocessing consists of the short-time Fourier transform(STFT) decomposition and detrending.The features are extracted from the entropy of spectrograms.The step of detrending makes the difference of the features between wheeze and normal lung sounds more obvious.Moreover,compared with the method whose decision is based on the empirical threshold,there is no uncertain detecting result any more.Results of two testing experiments show that the detecting accuracy(AC) are 97.1%and 95.7%,respectively,which proves that the proposed method could be an efficient way to detect wheeze. 展开更多
关键词 NLS Wheeze detecting method based on spectrogram entropy analysis STFT SVM
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Interface characterization of the discontinuously reinforced metal matrix composites based on wavelet analysis of acoustic emission behaviour 被引量:5
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《Chinese Science Bulletin》 SCIE CAS 1998年第9期791-792,共2页
关键词 Interface characterization of the discontinuously reinforced metal matrix composites based on wavelet analysis of acoustic emission behaviour
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Image registration based on matrix perturbation analysis using spectral graph 被引量:1
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作者 冷成财 田铮 +1 位作者 李婧 丁明涛 《Chinese Optics Letters》 SCIE EI CAS CSCD 2009年第11期996-1000,共5页
We present a novel perspective on characterizing the spectral correspondence between nodes of the weighted graph with application to image registration. It is based on matrix perturbation analysis on the spectral grap... We present a novel perspective on characterizing the spectral correspondence between nodes of the weighted graph with application to image registration. It is based on matrix perturbation analysis on the spectral graph. The contribution may be divided into three parts. Firstly, the perturbation matrix is obtained by perturbing the matrix of graph model. Secondly, an orthogonal matrix is obtained based on an optimal parameter, which can better capture correspondence features. Thirdly, the optimal matching matrix is proposed by adjusting signs of orthogonal matrix for image registration. Experiments on both synthetic images and real-world images demonstrate the effectiveness and accuracy of the proposed method. 展开更多
关键词 Image registration based on matrix perturbation analysis using spectral graph THH LH VHH SAR Ga
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Fast removal of ocular artifacts from electroencephalogram signals using spatial constraint independent component analysis based recursive least squares in brain-computer interface 被引量:1
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作者 Bang-hua YANG Liang-fei HE Lin LIN Qian WANG 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2015年第6期486-496,共11页
Ocular artifacts cause the main interfering signals within electroencephalogram (EEG) signal measurements. An adaptive filter based on reference signals from an electrooculogram (EOG) can reduce ocular interferenc... Ocular artifacts cause the main interfering signals within electroencephalogram (EEG) signal measurements. An adaptive filter based on reference signals from an electrooculogram (EOG) can reduce ocular interference, but collecting EOG signals during a long-term EEG recording is inconvenient and uncomfortable for the subject. To remove ocular artifacts from EEG in brain-computer interfaces (BCIs), a method named spatial constraint independent component analysis based recursive least squares (SCICA-RLS) is proposed. The method consists of two stages. In the first stage, independent component analysis (ICA) is used to decompose multiple EEG channels into an equal number of independent components (ICs). Ocular ICs are identified by an automatic artifact detection method based on kurtosis. Then empirical mode decomposition (EMD) is employed to remove any cerebral activity from the identified ocular ICs to obtain exact altifact ICs. In the second stage, first, SCICA applies exact artifact ICs obtained in the first stage as a constraint to extract artifact ICs from the given EEG signal. These extracted ICs are called spatial constraint ICs (SC-ICs). Then the RLS based adaptive filter uses SC-ICs as reference signals to reduce interference, which avoids the need for parallel EOG recordings. In addition, the proposed method has the ability of fast computation as it is not necessary for SCICA to identify all ICs like ICA. Based on the EEG data recorded from seven subjects, the new approach can lead to average classification accuracies of 3.3% and 12.6% higher than those of the standard ICA and raw EEG, respectively. In addition, the proposed method has 83.5% and 83.8% reduction in time-consumption compared with the standard ICA and ICA-RLS, respectively, which demonstrates a better and faster OA reduction. 展开更多
关键词 Ocular artifacts Electroencephalogram (EEG) Electrooculogram (EOG) Brain-computer interface (BCI) Spatialconstraint independent component analysis based recursive least squares (SCICA-RLS)
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Structural-acoustic topology optimization analysis based on evolutionary structural optimization approach 被引量:1
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作者 CHEN Luyun WANG Deyu (State Key Laboratory of Ocean Eng.,Shanghai Jiao Tong University Shanghai 200030) 《Chinese Journal of Acoustics》 2009年第4期332-342,共11页
The continuum structural-acoustic topology optimization with external loading is investigated herein. Finite element method (FEM) is used to obtain the structural frequency response and boundary element method (BEM... The continuum structural-acoustic topology optimization with external loading is investigated herein. Finite element method (FEM) is used to obtain the structural frequency response and boundary element method (BEM) is adopted to perform exterior acoustic radiation analysis. The evolutionary structural optimization (ESO) is served as an optimization method in structural-acoustic radiation topology analysis. The acoustic radiation optimization of a plate under harmonic excitation is given for example. The numerical results show that using ESO solution to analyze structural-acoustic topology optimization is feasible and effective. 展开更多
关键词 ESO Structural-acoustic topology optimization analysis based on evolutionary structural optimization approach
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Passive bearings-only target motion analysis based on association of multiple arrays 被引量:1
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作者 DU Xuanmin YAO Lan (Shanghai Marine Electronic Equipment Research Institute Shanghai 200025) 《Chinese Journal of Acoustics》 2000年第4期346-353,共8页
The method for Bearings-Only Target Motion Analysis (BO-TMA) based on bearing measurements fusion of two arrays is studied. The algorithms of pseudolinear processing, extended Kalman filter and maximum likelihood est... The method for Bearings-Only Target Motion Analysis (BO-TMA) based on bearing measurements fusion of two arrays is studied. The algorithms of pseudolinear processing, extended Kalman filter and maximum likelihood estimation are presented. The results of simulation experiments show that the BO-TMA method based on association of multiple arrays not only makes contributions towards eliminating maneuvers needed by bearings-only TMA based on single array,but also improves the stabilization and global convergence for varied estimation algorithms. 展开更多
关键词 Passive bearings-only target motion analysis based on association of multiple arrays TMA
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Design and analysis of superlens based on complex two-dimensional square lattice photonic crystal 被引量:2
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作者 Somayeh Rafiee Dastjerdi Majid Ghanaatshoar Toshiaki Hattori 《Chinese Optics Letters》 SCIE EI CAS CSCD 2013年第10期83-86,共4页
We theoretically demonstrate the imaging properties of a complex two-dimensional(2D) face-centered square lattice photonic crystal(PC) made from germanium cylinders in air background. The finitedifference time-domain(... We theoretically demonstrate the imaging properties of a complex two-dimensional(2D) face-centered square lattice photonic crystal(PC) made from germanium cylinders in air background. The finitedifference time-domain(FDTD) method is employed to calculate the band structure and simulate image construction. The band diagram of the complex structure is significantly compressed. Negative refraction occurs in the second energy band with negative phase velocity at a frequency of 0.228(2πc/a), which is lower than results from previous studies. Lower negative refraction frequency leads to higher image resolution. Numerical results show that the spatial resolution of the system reaches 0.7296λ, which is lower than the incident wavelength. 展开更多
关键词 Design and analysis of superlens based on complex two-dimensional square lattice photonic crystal
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弱碱三元复合驱采出液处理系统运行效果分析 被引量:2
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作者 吴新勃 胡登艳 张世林 《全面腐蚀控制》 2022年第2期57-58,共2页
结合弱碱三元复合驱采出液处理系统运行中出现的采出液成分复杂、处理难度大、脱水系统运行不平稳等问题,通过采取适时合理的指标调整、药剂优化、运行优化、工艺完善等措施,对运行效果进行了分析,也保障了集输系统平稳运行。
关键词 弱碱三元复合驱 采出液处理 运行效果 分析
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