High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a ...High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a custom-designed hybrid electrovibration and mechanical vibration(HEM)device.An electrovibration and mechanical vibration(EMV)algorithm that renders 3D gratings with different physical heights was proposed and shown to achieve 81%accuracy in shape recognition.Models of tactile rendering fidelity were established based on the evaluation of the height discrimination threshold,and the psychophysical-physical relationships between the discrimination and reference heights were well described by a modification of Weber’s law,with correlation coefficients higher than 0.9.The physiological-physical relationship between the pulse firing rate and the physical stimulation voltage was modeled using the Izhikevich spiking model with a logarithmic relationship.展开更多
A spike response model(SRM)based on the spikes generator circuit(SGC)of adaptive fuzzy spiking neurons(AFSNs)is developed.The SRM is simulated in MatlabTM environment.The proposed model is applied to a configuration o...A spike response model(SRM)based on the spikes generator circuit(SGC)of adaptive fuzzy spiking neurons(AFSNs)is developed.The SRM is simulated in MatlabTM environment.The proposed model is applied to a configuration of a fuzzy exclusive or(fuzzy XOR)operator,as an illustrative example.A description of the comparison of AFSNs with other similar methods is given.The novel method of the AFSNs is used to determine the value of the weights or parameters of the fuzzy XOR,first with dynamic weights or self-tuning parameters that adapt continuously,then with fixed weights obtained after training,finally with fixed weights and a dynamic gain or self-tuning gain for a fine adjustment of amplitude.展开更多
The interaction of the heavy charged particles, of energy higher than a few MeV/amu with semiconductor single crystals can lead to the structural modification of their physical properties and participate at the creati...The interaction of the heavy charged particles, of energy higher than a few MeV/amu with semiconductor single crystals can lead to the structural modification of their physical properties and participate at the creation of the defects which are called latent tracks. Several models were tested for explaining the track formation in semiconductors irradiated with swift heavy ions, one of them is the thermal spike model. This work shows that the experimental data obtained in semiconductors, in our case in InP irradiated with swift heavy ions can be described on the basis of the thermal spike model. The experimental results obtained on InP have allowed the parameters of this model to be understood. The only free parameter is the electron-phonon coupling constant g which is unknown in InP This model allows the evolution of track radii to be found as a function of electronic stopping power （dE/dx）e for different beam energies. For InP a good agreement is observed between calculated track radii and experimental ones on one hand, and on the other hand between calculated and experimental threshold value of electronic stopping power. This allows determining the electron-phonon coupling value for InP to be equal 0.9 × 10%11 Wcm-3K-land the （dE/dx）e threshold for latent track formation in InP equal 27 ＋ 3 keV/nm for ion energies ranging from 0.4-10 MeV/amu.展开更多
The primary motivation for studying how irradiation modifies the structures and properties of solid materials involves the understanding of undesirable phenomena,including irradiation-induced degradation of components...The primary motivation for studying how irradiation modifies the structures and properties of solid materials involves the understanding of undesirable phenomena,including irradiation-induced degradation of components in nuclear reactors and space exploration,and beneficial applications,including material performance tailoring through ion beam modification and defect engineering.In this work,the formation mechanism of latent tracks with different damage morphologies in LiNbO_(3)crystals under 0.09-6.17 Me V/u ion irradiation with an electronic energy loss from 2.6-13.2 ke V/nm is analyzed by experimental characterizations and numerical calculations.Irradiation-induced damage is preliminarily evaluated via the prism coupling technique to analyze the correlation between the dark-mode spectra and energy loss profiles of irradiated regions.Under the irradiation conditions of different ion velocities and electronic energy losses,different damage morphologies,from individual spherical defects to discontinuous and continuous tracks,are experimentally characterized.During ion penetration process,the ion velocity determines the spatiotemporal distribution of deposited irradiation energy induced by electronic energy loss,meaning that the two essential factors including electronic energy loss and ion velocity coaffect the track damage.The inelastic thermal spike model is used to numerically calculate the spatiotemporal evolutions of energy deposition and the corresponding atomic temperature under different irradiation conditions,and a quantitative relationship is proposed by comparison with corresponding experimentally observed track damage morphologies.The obtained quantitative relationship between irradiation conditions and track damage provides deep insight and guidance for understanding the damage behavior of crystal materials in extreme radiation environments and selecting irradiation parameters,including ion species and energies,for ion beam technique application in atomic-level defect manipulation,material modification,and micro/nanofabrication.展开更多
The focus of this study is to explore the mechanisms during seizure behavior using a physiologically motivated by corticothalamic circuity. The model is based on the assumption that, the inhibitory projects from thala...The focus of this study is to explore the mechanisms during seizure behavior using a physiologically motivated by corticothalamic circuity. The model is based on the assumption that, the inhibitory projects from thalamus reticular nucleus(TRN) to specific relay nuclei(SRN) are mediated by GABAA and GABAB receptors which react different time scales in synaptic transmission.Secondly, we include the effects of slow modulation on the threshold current of TRN population that were found to generate bursting behavior. Our model can reproduce healthy and pathological dynamics including wake, spindle, deep sleep, and also seizure states. In addition, contour maps are used to explore the transition of different activity states. It is worthy to point out seizure duration is significantly affected by a time-varying delay as illustrated in our numerical simulation. Finally, a reduced model ignoring the cerebral cortex mass can also capture the feature of spike wave discharge as generated in the full network.展开更多
In this paper,we propose a criterion based on the variance variation of the sample eigenvalues to correctly estimate the number of significant components in high-dimensional principal component analysis(PCA),and it co...In this paper,we propose a criterion based on the variance variation of the sample eigenvalues to correctly estimate the number of significant components in high-dimensional principal component analysis(PCA),and it corresponds to the number of significant eigenvalues of the covariance matrix for p-dimensional variables.Using the random matrix theory,we derive that the consistent properties of the proposed criterion for the situations that the significant eigenvalues tend to infinity,as well as that the bounded significant population eigenvalues.Numerical simulation shows that the probability of estimator is correct by our variance variation criterion converges to 1 is faster than that by criterion of Passemier and Yao[Estimation of the number of spikes,possibly equal,in the high-dimensional case.J.Multivariate Anal.,(2014)](PYC),AIC and BIC under the finite fourth moment condition as the dominant population eigenvalues tend to infinity.Moreover,in the case of the maximum eigenvalue bounded,once the gap condition is satisfied,the rate of convergence to 1 is faster than that of PYC and AIC,especially the effect is better than AIC when the sample size is small.It is worth noting that the variance variation criterion significantly improves the accuracy of model selection compared with PYC and AIC when the random variable is a heavy-tailed distribution or finite fourth moment not exists.展开更多
This paper addresses the issue of testing sphericity and identity of high-dimensional population covariance matrix when the data dimension exceeds the sample size.The central limit theorem of the first four moments of...This paper addresses the issue of testing sphericity and identity of high-dimensional population covariance matrix when the data dimension exceeds the sample size.The central limit theorem of the first four moments of eigenvalues of sample covariance matrix is derived using random matrix theory for generally distributed populations.Further,some desirable asymptotic properties of the proposed test statistics are provided under the null hypothesis as data dimension and sample size both tend to infinity.Simulations show that the proposed tests have a greater power than existing methods for the spiked covariance model.展开更多
基金Supported by the National Natural Science Foundation of China under Grants 61631010 and 61806085.
文摘High-fidelity tactile rendering offers significant potential for improving the richness and immersion of touchscreen interactions.This study focuses on a quantitative description of tactile rendering fidelity using a custom-designed hybrid electrovibration and mechanical vibration(HEM)device.An electrovibration and mechanical vibration(EMV)algorithm that renders 3D gratings with different physical heights was proposed and shown to achieve 81%accuracy in shape recognition.Models of tactile rendering fidelity were established based on the evaluation of the height discrimination threshold,and the psychophysical-physical relationships between the discrimination and reference heights were well described by a modification of Weber’s law,with correlation coefficients higher than 0.9.The physiological-physical relationship between the pulse firing rate and the physical stimulation voltage was modeled using the Izhikevich spiking model with a logarithmic relationship.
文摘A spike response model(SRM)based on the spikes generator circuit(SGC)of adaptive fuzzy spiking neurons(AFSNs)is developed.The SRM is simulated in MatlabTM environment.The proposed model is applied to a configuration of a fuzzy exclusive or(fuzzy XOR)operator,as an illustrative example.A description of the comparison of AFSNs with other similar methods is given.The novel method of the AFSNs is used to determine the value of the weights or parameters of the fuzzy XOR,first with dynamic weights or self-tuning parameters that adapt continuously,then with fixed weights obtained after training,finally with fixed weights and a dynamic gain or self-tuning gain for a fine adjustment of amplitude.
文摘The interaction of the heavy charged particles, of energy higher than a few MeV/amu with semiconductor single crystals can lead to the structural modification of their physical properties and participate at the creation of the defects which are called latent tracks. Several models were tested for explaining the track formation in semiconductors irradiated with swift heavy ions, one of them is the thermal spike model. This work shows that the experimental data obtained in semiconductors, in our case in InP irradiated with swift heavy ions can be described on the basis of the thermal spike model. The experimental results obtained on InP have allowed the parameters of this model to be understood. The only free parameter is the electron-phonon coupling constant g which is unknown in InP This model allows the evolution of track radii to be found as a function of electronic stopping power （dE/dx）e for different beam energies. For InP a good agreement is observed between calculated track radii and experimental ones on one hand, and on the other hand between calculated and experimental threshold value of electronic stopping power. This allows determining the electron-phonon coupling value for InP to be equal 0.9 × 10%11 Wcm-3K-land the （dE/dx）e threshold for latent track formation in InP equal 27 ＋ 3 keV/nm for ion energies ranging from 0.4-10 MeV/amu.
基金supported by the National Natural Science Foundation of China(No.11875038)the National Laboratory of Heavy Ion Accelerator in Lanzhou,and the State Key Laboratory of Nuclear Physics and Technology,Peking University+2 种基金financial support from the Young Scholars Program of Shandong Universityfinancial support from the Youth Innovation Promotion Association CAS(No.2019262)supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,Materials Sciences and Engineering Division。
文摘The primary motivation for studying how irradiation modifies the structures and properties of solid materials involves the understanding of undesirable phenomena,including irradiation-induced degradation of components in nuclear reactors and space exploration,and beneficial applications,including material performance tailoring through ion beam modification and defect engineering.In this work,the formation mechanism of latent tracks with different damage morphologies in LiNbO_(3)crystals under 0.09-6.17 Me V/u ion irradiation with an electronic energy loss from 2.6-13.2 ke V/nm is analyzed by experimental characterizations and numerical calculations.Irradiation-induced damage is preliminarily evaluated via the prism coupling technique to analyze the correlation between the dark-mode spectra and energy loss profiles of irradiated regions.Under the irradiation conditions of different ion velocities and electronic energy losses,different damage morphologies,from individual spherical defects to discontinuous and continuous tracks,are experimentally characterized.During ion penetration process,the ion velocity determines the spatiotemporal distribution of deposited irradiation energy induced by electronic energy loss,meaning that the two essential factors including electronic energy loss and ion velocity coaffect the track damage.The inelastic thermal spike model is used to numerically calculate the spatiotemporal evolutions of energy deposition and the corresponding atomic temperature under different irradiation conditions,and a quantitative relationship is proposed by comparison with corresponding experimentally observed track damage morphologies.The obtained quantitative relationship between irradiation conditions and track damage provides deep insight and guidance for understanding the damage behavior of crystal materials in extreme radiation environments and selecting irradiation parameters,including ion species and energies,for ion beam technique application in atomic-level defect manipulation,material modification,and micro/nanofabrication.
基金supported by the Foundational Research Funds for the Central Universities(Grant Nos.G2016KY0301)the National Natural Science Foundation of China(Grant Nos.11602192&11672074)
文摘The focus of this study is to explore the mechanisms during seizure behavior using a physiologically motivated by corticothalamic circuity. The model is based on the assumption that, the inhibitory projects from thalamus reticular nucleus(TRN) to specific relay nuclei(SRN) are mediated by GABAA and GABAB receptors which react different time scales in synaptic transmission.Secondly, we include the effects of slow modulation on the threshold current of TRN population that were found to generate bursting behavior. Our model can reproduce healthy and pathological dynamics including wake, spindle, deep sleep, and also seizure states. In addition, contour maps are used to explore the transition of different activity states. It is worthy to point out seizure duration is significantly affected by a time-varying delay as illustrated in our numerical simulation. Finally, a reduced model ignoring the cerebral cortex mass can also capture the feature of spike wave discharge as generated in the full network.
基金partly supported by National Natural Science Foundation of China(Nos:12031016,11971324,11471223)Foundations of Science and Technology Innovation Service Capacity Building,Interdisciplinary Construction of Bioinformatics and StatisticsAcademy for Multidisciplinary Studies,Capital Normal University,Beijing。
文摘In this paper,we propose a criterion based on the variance variation of the sample eigenvalues to correctly estimate the number of significant components in high-dimensional principal component analysis(PCA),and it corresponds to the number of significant eigenvalues of the covariance matrix for p-dimensional variables.Using the random matrix theory,we derive that the consistent properties of the proposed criterion for the situations that the significant eigenvalues tend to infinity,as well as that the bounded significant population eigenvalues.Numerical simulation shows that the probability of estimator is correct by our variance variation criterion converges to 1 is faster than that by criterion of Passemier and Yao[Estimation of the number of spikes,possibly equal,in the high-dimensional case.J.Multivariate Anal.,(2014)](PYC),AIC and BIC under the finite fourth moment condition as the dominant population eigenvalues tend to infinity.Moreover,in the case of the maximum eigenvalue bounded,once the gap condition is satisfied,the rate of convergence to 1 is faster than that of PYC and AIC,especially the effect is better than AIC when the sample size is small.It is worth noting that the variance variation criterion significantly improves the accuracy of model selection compared with PYC and AIC when the random variable is a heavy-tailed distribution or finite fourth moment not exists.
基金supported by the National Natural Science Foundation of China(Nos.61374027,11871357)the Sichuan Science and Technology Program(Nos.2019YJ0122)。
文摘This paper addresses the issue of testing sphericity and identity of high-dimensional population covariance matrix when the data dimension exceeds the sample size.The central limit theorem of the first four moments of eigenvalues of sample covariance matrix is derived using random matrix theory for generally distributed populations.Further,some desirable asymptotic properties of the proposed test statistics are provided under the null hypothesis as data dimension and sample size both tend to infinity.Simulations show that the proposed tests have a greater power than existing methods for the spiked covariance model.
