Certain insect species have been observed to exploit the resonance mechanism of their wings.In order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency...Certain insect species have been observed to exploit the resonance mechanism of their wings.In order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)analysis.However,there exists controversy among researchers regarding the relationship between frequency and aerodynamic performance.Recognizing that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant frequency.In this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM analyses.The performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic performance.Notably,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum efficiency.Thus,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible wings.Furthermore,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure changes.This paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.展开更多
This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-...This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-of-plane motions are obtained employing the von Kármán plate theory as well as Kirchhoff＇s hypotheses by means of the Lagrange equations. The equations of motions are solved using the pseudo-arclength continuation technique and direct timeintegration method. The system parameters are tuned to the values associated with modal interactions, and then nonlinear resonant responses and energy transfer are analysed.Nonlinear motion characteristics are shown in the form of frequency-response and force-response curves, time histories, phase-plane portraits, and fast Fourier transforms.展开更多
The fusion of millimeter-wave radar and camera modalities is crucial for improving the accuracy and completeness of 3-dimensional(3D)object detection.Most existing methods extract features from each modality separatel...The fusion of millimeter-wave radar and camera modalities is crucial for improving the accuracy and completeness of 3-dimensional(3D)object detection.Most existing methods extract features from each modality separately and conduct fusion with specifically designed modules,potentially resulting in information loss during modality transformation.To address this issue,we propose a novel framework for 3D object detection that iteratively updates radar and camera features through an interaction module.This module serves a dual purpose by facilitating the fusion of multi-modal data while preserving the original features.Specifically,radar and image features are sampled and aggregated with a set of sparse 3D object queries,while retaining the integrity of the original radar features to prevent information loss.Additionally,an innovative radar augmentation technique named Radar Gaussian Expansion is proposed.This module allocates radar measurements within each voxel to neighboring ones as a Gaussian distribution,reducing association errors during projection and enhancing detection accuracy.Our proposed framework offers a comprehensive solution to the fusion of radar and camera data,ultimately leading to heightened accuracy and completeness in 3D object detection processes.On the nuScenes test benchmark,our camera-radar fusion method achieves state-of-the-art 3D object detection results with a 41.6% mean average precision and 52.5% nuScenes detection score.展开更多
This paper proposes a two-to-one internal resonance to widen the bandwidth of vibratory energy harvesters.To describe the improved characteristic,an electromagnetic spring-pendulum harvester is designed.Approximate an...This paper proposes a two-to-one internal resonance to widen the bandwidth of vibratory energy harvesters.To describe the improved characteristic,an electromagnetic spring-pendulum harvester is designed.Approximate analytical solutions of the electromechanical coupled system are carried out by introducing the method of multiple scales,and the frequency response relationships of the displacement and the current are obtained.The character of broadband harvesting performance is examined,the two peaks and double jump phenomena for variation of design parameters were observed.The effect of key control parameters on the harvesters bandwidth is considered,and the nonlinear behaviors of the harvester are validated via numerical results.展开更多
We design an electromechanical transducer harvesting system with one-to-one internal resonance that can emerge a broader spectrum vibrations. The novel harvester is composed of a Duffing electrical circuit coupled to ...We design an electromechanical transducer harvesting system with one-to-one internal resonance that can emerge a broader spectrum vibrations. The novel harvester is composed of a Duffing electrical circuit coupled to a mobile rod, and the coupling between both components is realized via the electromagnetic force. Approximate analytical solutions of the electromechanical system are carried out by introducing the multiple scales analysis, also the nonlinear modulation equation for one-to-one internal resonance is obtained. The character of broadband harvesting performance are analyzed, the two peaks and one jump phenomenon bending to the right for variation of control parameters are observed. It is shown that an advanced bandwidth over a corresponding linear model that does not possess a modal energy interchange.展开更多
This paper presents a novel technique for low-power generation of frequency combs(FC)over a wide frequency range.It leverages modal interactions between electrical and mechanical resonators in electrostatic NEMS opera...This paper presents a novel technique for low-power generation of frequency combs(FC)over a wide frequency range.It leverages modal interactions between electrical and mechanical resonators in electrostatic NEMS operating in air to provide a simple architecture for FC generators.A biased voltage signal drives the electrical resonator at resonance which is set to match an integer submultiple of twice the mechanical resonator’s resonance.Experimental results demonstrate that the NEMS displacement exhibit more than 150 equidistant peaks in the case of a 2:1 modal interaction and more than 60 equidistant peaks in the case of a 1:1 modal interaction.In both cases,the Free Spectral Range(FSR)was equal to the mechanical resonance frequency.Comparison between the FCs generated by the 2:1 and 1:1 modal interactions demonstrate the superiority of the former in terms of bandwidth and stability.The superior phase coherence of the FC generated via the 2:1 modal interaction was demonstrated via time-domain analysis.Our technique has the flexibility to generate multiple frequency combs and to fine-tune their FSR depending on the number of mechanical modes accessible to and the order of the activated modal interaction.It can be integrated into portable devices and is well aligned with modern miniaturization technology.展开更多
In the realm of human-computer interaction, accurately discerning the user's emotional state during a conversation has become increasingly critical. Multimodal emotion recognition has garnered considerable attenti...In the realm of human-computer interaction, accurately discerning the user's emotional state during a conversation has become increasingly critical. Multimodal emotion recognition has garnered considerable attention.However, the task of multimodal emotion recognition still faces several challenges. Especially, the models are unable to effectively extract multimodal contextual and interaction information, which results in a significant redundancy in the concatenated features representation. To mitigate this issue, a cross-modal fusion network based on graph feature learning(CFNet-GFL) model is proposed. Firstly, the model employs a cross-modal module to integrate multiple feature representations, resulting in more precise feature embedding. This alleviates the issue of information redundancy in the fusion process. Secondly, the model leverages a graph feature learning approach to extract intra-modal contextual preferences and inter-modal information interactions. By capturing the diversity and consistency of multimodal information, the model enhances the ability to understand emotions. Finally, the performance of the CFNet-GFL model is demonstrated by some experiments on the IEMOCAP and MELD datasets. The w-F1 scores show a significant improvement of approximately 2.08% and 1.36% respectively. These findings demonstrate the effectiveness of the model in multimodal emotion recognition.展开更多
Multimodal Sentiment analysis refers to analyzing emotions in infor-mation carriers containing multiple modalities.To better analyze the features within and between modalities and solve the problem of incomplete multi...Multimodal Sentiment analysis refers to analyzing emotions in infor-mation carriers containing multiple modalities.To better analyze the features within and between modalities and solve the problem of incomplete multimodal feature fusion,this paper proposes a multimodal sentiment analysis model MIF(Modal Interactive Feature Encoder For Multimodal Sentiment Analysis).First,the global features of three modalities are obtained through unimodal feature extraction networks.Second,the inter-modal interactive feature encoder and the intra-modal interactive feature encoder extract similarity features between modal-ities and intra-modal special features separately.Finally,unimodal special features and the interaction information between modalities are decoded to get the fusion features and predict sentimental polarity results.We conduct extensive experi-ments on three public multimodal datasets,including one in Chinese and two in English.The results show that the performance of our approach is significantly improved compared with benchmark models.展开更多
基金This study was co-supported by the National Natural Science Foundation of China(No.52275293)the Guangdong Basic and Applied Basic Research Foundation,China(No.2023A1515010774)+1 种基金the Basic Research Program of Shenzhen,China(No.JCYJ 20190806142816524)the National Key Laboratory of Science and Technology on Aerodynamic Design and Research,China(No.61422010301).
文摘Certain insect species have been observed to exploit the resonance mechanism of their wings.In order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)analysis.However,there exists controversy among researchers regarding the relationship between frequency and aerodynamic performance.Recognizing that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant frequency.In this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM analyses.The performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic performance.Notably,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum efficiency.Thus,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible wings.Furthermore,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure changes.This paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.
文摘This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-of-plane motions are obtained employing the von Kármán plate theory as well as Kirchhoff＇s hypotheses by means of the Lagrange equations. The equations of motions are solved using the pseudo-arclength continuation technique and direct timeintegration method. The system parameters are tuned to the values associated with modal interactions, and then nonlinear resonant responses and energy transfer are analysed.Nonlinear motion characteristics are shown in the form of frequency-response and force-response curves, time histories, phase-plane portraits, and fast Fourier transforms.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(No.62203289)the Shanghai Sailing Program(No.22YF1413800)+1 种基金the National Natural Science Foundation of China(No.52371371)the Shanghai Municipal Natural Science Foundation(No.21ZR1423300).
文摘The fusion of millimeter-wave radar and camera modalities is crucial for improving the accuracy and completeness of 3-dimensional(3D)object detection.Most existing methods extract features from each modality separately and conduct fusion with specifically designed modules,potentially resulting in information loss during modality transformation.To address this issue,we propose a novel framework for 3D object detection that iteratively updates radar and camera features through an interaction module.This module serves a dual purpose by facilitating the fusion of multi-modal data while preserving the original features.Specifically,radar and image features are sampled and aggregated with a set of sparse 3D object queries,while retaining the integrity of the original radar features to prevent information loss.Additionally,an innovative radar augmentation technique named Radar Gaussian Expansion is proposed.This module allocates radar measurements within each voxel to neighboring ones as a Gaussian distribution,reducing association errors during projection and enhancing detection accuracy.Our proposed framework offers a comprehensive solution to the fusion of radar and camera data,ultimately leading to heightened accuracy and completeness in 3D object detection processes.On the nuScenes test benchmark,our camera-radar fusion method achieves state-of-the-art 3D object detection results with a 41.6% mean average precision and 52.5% nuScenes detection score.
基金supported by the National Natural Science Foundation of China(Grants 11632008,11702119,and 11972173)the Natural Science Foundation of Jiangsu Province(Grant BK20170565)+1 种基金the Qing Lan Project of Jiangsu Provincethe Training program for Young Talents of Jiangsu University.
文摘This paper proposes a two-to-one internal resonance to widen the bandwidth of vibratory energy harvesters.To describe the improved characteristic,an electromagnetic spring-pendulum harvester is designed.Approximate analytical solutions of the electromechanical coupled system are carried out by introducing the method of multiple scales,and the frequency response relationships of the displacement and the current are obtained.The character of broadband harvesting performance is examined,the two peaks and double jump phenomena for variation of design parameters were observed.The effect of key control parameters on the harvesters bandwidth is considered,and the nonlinear behaviors of the harvester are validated via numerical results.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11632008 and 11702119)the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20170565)+1 种基金China Postdoctoral Science Foundation (Grant No. 2020M671353)Jiangsu Planned Projects for Postdoctoral Research Funds, China (Grant No. 2020Z376)。
文摘We design an electromechanical transducer harvesting system with one-to-one internal resonance that can emerge a broader spectrum vibrations. The novel harvester is composed of a Duffing electrical circuit coupled to a mobile rod, and the coupling between both components is realized via the electromagnetic force. Approximate analytical solutions of the electromechanical system are carried out by introducing the multiple scales analysis, also the nonlinear modulation equation for one-to-one internal resonance is obtained. The character of broadband harvesting performance are analyzed, the two peaks and one jump phenomenon bending to the right for variation of control parameters are observed. It is shown that an advanced bandwidth over a corresponding linear model that does not possess a modal energy interchange.
基金K.M.acknowledges funding from the Canada Foundation for Innovation John R.Evans Leaders Fund(Project 35552)Ontario Research Fund—Research Infrastructure(Project 35552),the Waterloo Institute for Nanotechnology(WIN-NRC seed grant),and a Mitacs Globalink Research Award.
文摘This paper presents a novel technique for low-power generation of frequency combs(FC)over a wide frequency range.It leverages modal interactions between electrical and mechanical resonators in electrostatic NEMS operating in air to provide a simple architecture for FC generators.A biased voltage signal drives the electrical resonator at resonance which is set to match an integer submultiple of twice the mechanical resonator’s resonance.Experimental results demonstrate that the NEMS displacement exhibit more than 150 equidistant peaks in the case of a 2:1 modal interaction and more than 60 equidistant peaks in the case of a 1:1 modal interaction.In both cases,the Free Spectral Range(FSR)was equal to the mechanical resonance frequency.Comparison between the FCs generated by the 2:1 and 1:1 modal interactions demonstrate the superiority of the former in terms of bandwidth and stability.The superior phase coherence of the FC generated via the 2:1 modal interaction was demonstrated via time-domain analysis.Our technique has the flexibility to generate multiple frequency combs and to fine-tune their FSR depending on the number of mechanical modes accessible to and the order of the activated modal interaction.It can be integrated into portable devices and is well aligned with modern miniaturization technology.
基金supported by National Natural Science Foundation of China (62201452)。
文摘In the realm of human-computer interaction, accurately discerning the user's emotional state during a conversation has become increasingly critical. Multimodal emotion recognition has garnered considerable attention.However, the task of multimodal emotion recognition still faces several challenges. Especially, the models are unable to effectively extract multimodal contextual and interaction information, which results in a significant redundancy in the concatenated features representation. To mitigate this issue, a cross-modal fusion network based on graph feature learning(CFNet-GFL) model is proposed. Firstly, the model employs a cross-modal module to integrate multiple feature representations, resulting in more precise feature embedding. This alleviates the issue of information redundancy in the fusion process. Secondly, the model leverages a graph feature learning approach to extract intra-modal contextual preferences and inter-modal information interactions. By capturing the diversity and consistency of multimodal information, the model enhances the ability to understand emotions. Finally, the performance of the CFNet-GFL model is demonstrated by some experiments on the IEMOCAP and MELD datasets. The w-F1 scores show a significant improvement of approximately 2.08% and 1.36% respectively. These findings demonstrate the effectiveness of the model in multimodal emotion recognition.
文摘Multimodal Sentiment analysis refers to analyzing emotions in infor-mation carriers containing multiple modalities.To better analyze the features within and between modalities and solve the problem of incomplete multimodal feature fusion,this paper proposes a multimodal sentiment analysis model MIF(Modal Interactive Feature Encoder For Multimodal Sentiment Analysis).First,the global features of three modalities are obtained through unimodal feature extraction networks.Second,the inter-modal interactive feature encoder and the intra-modal interactive feature encoder extract similarity features between modal-ities and intra-modal special features separately.Finally,unimodal special features and the interaction information between modalities are decoded to get the fusion features and predict sentimental polarity results.We conduct extensive experi-ments on three public multimodal datasets,including one in Chinese and two in English.The results show that the performance of our approach is significantly improved compared with benchmark models.
