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Deep brain implantable microelectrode arrays for detection and functional localization of the subthalamic nucleus in rats with Parkinson’s disease 被引量:1
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作者 Luyi Jing Zhaojie Xu +11 位作者 Penghui Fan Botao Lu Fan Mo Ruilin Hu Wei Xu Jin Shan Qianli Jia Yuxin Zhu Yiming Duan Mixia Wang Yirong Wu Xinxia Cai 《Bio-Design and Manufacturing》 SCIE EI CAS CSCD 2024年第4期439-452,共14页
The subthalamic nucleus(STN)is considered the best target for deep brain stimulation treatments of Parkinson’s disease(PD).It is difficult to localize the STN due to its small size and deep location.Multichannel micr... The subthalamic nucleus(STN)is considered the best target for deep brain stimulation treatments of Parkinson’s disease(PD).It is difficult to localize the STN due to its small size and deep location.Multichannel microelectrode arrays(MEAs)can rapidly and precisely locate the STN,which is important for precise stimulation.In this paper,16-channel MEAs modified with multiwalled carbon nanotube/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(MWCNT/PEDOT:PSS)nanocomposites were designed and fabricated,and the accurate and rapid identification of the STN in PD rats was performed using detection sites distributed at different brain depths.These results showed that nuclei in 6-hydroxydopamine hydrobromide(6-OHDA)-lesioned brains discharged more intensely than those in unlesioned brains.In addition,the MEA simultaneously acquired neural signals from both the STN and the upper or lower boundary nuclei of the STN.Moreover,higher values of spike firing rate,spike amplitude,local field potential(LFP)power,and beta oscillations were detected in the STN of the 6-OHDA-lesioned brain,and may therefore be biomarkers of STN localization.Compared with the STNs of unlesioned brains,the power spectral density of spikes and LFPs synchronously decreased in the delta band and increased in the beta band of 6-OHDA-lesioned brains.This may be a cause of sleep and motor disorders associated with PD.Overall,this work describes a new cellular-level localization and detection method and provides a tool for future studies of deep brain nuclei. 展开更多
关键词 functional localization Implantable microelectrode arrays Parkinson’s disease subthalamic nucleus
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On the Weyl’s Lemma for Triharmonic Functions
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作者 ZHENG Run-jie ZENG Jia-min FANG Yi 《Chinese Quarterly Journal of Mathematics》 2024年第3期288-294,共7页
In this paper,by choosing some appropriate test functions,we prove the Weyl’s lemma for triharmonic functions based on the new type of mean value formulas.
关键词 Weyl’s lemma Harmonic functions Triharmonic functions Test functions Mean value formulas
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Evaluation of Generalized Error Function via Fast-Converging Power Series
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作者 Serdar Beji 《Advances in Pure Mathematics》 2024年第6期495-514,共20页
A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power... A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power series expansion developed in resolving the so-called Grandi’s paradox. Comparisons with accurate tabulated values for well-known cases such as the error function are presented using the expansions truncated at various orders. 展开更多
关键词 Generalized Error function Gamma function Grandi’s Paradox Fast-Converging Power series
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A hybrid method integrating Green's function Monte Carlo and projected entangled pair states
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作者 He-Yu Lin Rong-Qiang He +1 位作者 Yibin Guo Zhong-Yi Lu 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第11期75-81,共7页
This paper introduces a hybrid approach combining Green’s function Monte Carlo(GFMC)method with projected entangled pair state(PEPS)ansatz.This hybrid method regards PEPS as a trial state and a guiding wave function ... This paper introduces a hybrid approach combining Green’s function Monte Carlo(GFMC)method with projected entangled pair state(PEPS)ansatz.This hybrid method regards PEPS as a trial state and a guiding wave function in GFMC.By leveraging PEPS’s proficiency in capturing quantum state entanglement and GFMC’s efficient parallel architecture,the hybrid method is well-suited for the accurate and efficient treatment of frustrated quantum spin systems.As a benchmark,we applied this approach to study the frustrated J_(1)–J_(2) Heisenberg model on a square lattice with periodic boundary conditions(PBCs).Compared with other numerical methods,our approach integrating PEPS and GFMC shows competitive accuracy in the performance of ground-state energy.This paper provides systematic and comprehensive discussion of the approach of our previous work[Phys.Rev.B 109235133(2024)]. 展开更多
关键词 projected entangled pair states Green’s function Monte Carlo frustrated J_(1)-J_(2)Heisenberg model
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Implementation of the Integrated Green’s Function Method for 3D Poisson’s Equation in a Large Aspect Ratio Computational Domain
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作者 Ji Qiang Chad Mitchell +1 位作者 Remi Lehe Arianna Formenti 《Journal of Software Engineering and Applications》 2024年第9期740-749,共10页
The solution of Poisson’s Equation plays an important role in many areas, including modeling high-intensity and high-brightness beams in particle accelerators. For the computational domain with a large aspect ratio, ... The solution of Poisson’s Equation plays an important role in many areas, including modeling high-intensity and high-brightness beams in particle accelerators. For the computational domain with a large aspect ratio, the integrated Green’s function method has been adopted to solve the 3D Poisson equation subject to open boundary conditions. In this paper, we report on the efficient implementation of this method, which can save more than a factor of 50 computing time compared with the direct brute force implementation and its improvement under certain extreme conditions. 展开更多
关键词 Green’s function Poisson Equation Particle Accelerator
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Existence of Monotone Positive Solution for a Fourth-Order Three-Point BVP with Sign-Changing Green’s Function
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作者 Junrui Yue Yun Zhang Qingyue Bai 《Open Journal of Applied Sciences》 2024年第1期63-69,共7页
This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones a... This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones and iterative technique. 展开更多
关键词 Fourth-Order Three-Point Boundary Value Problem sign-Changing Green’s function Fixed Point Index Iterative Technique Monotone Positive solution EXIsTENCE
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A Set of Almost Automorphic Functions and Applications
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作者 William Dimbour Vincent Valmorin 《Applied Mathematics》 2024年第1期9-21,共13页
For a set S of real numbers, we introduce the concept of S-almost automorphic functions valued in a Banach space. It generalizes in particular the space of Z-almost automorphic functions. Considering the space of S-al... For a set S of real numbers, we introduce the concept of S-almost automorphic functions valued in a Banach space. It generalizes in particular the space of Z-almost automorphic functions. Considering the space of S-almost automorphic functions, we give sufficient conditions of the existence and uniqueness of almost automorphic solutions of a differential equation with a piecewise constant argument of generalized type. This is done using the Banach fixed point theorem. 展开更多
关键词 Almost Automorphic functions s-Almost Automorphic functions Differential Equation with Piecewise Constant Argument of Generalized Type
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高压管汇材料疲劳性能测试及P-S-N模型曲线的拟合 被引量:1
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作者 黄艳娟 周思柱 李宁 《长江大学学报(自然科学版)》 2024年第3期55-61,共7页
高压管汇作为压裂设备中的主要易损件之一,其失效危害较大。它的失效原因主要是疲劳、冲蚀、腐蚀或者材料缺陷引起的刺漏和爆裂,其中尤以疲劳失效最不可预估。目前,对于高压管汇材料的疲劳性能研究不够深入,为解决高压管汇材料疲劳寿命... 高压管汇作为压裂设备中的主要易损件之一,其失效危害较大。它的失效原因主要是疲劳、冲蚀、腐蚀或者材料缺陷引起的刺漏和爆裂,其中尤以疲劳失效最不可预估。目前,对于高压管汇材料的疲劳性能研究不够深入,为解决高压管汇材料疲劳寿命的准确描述问题,以某国产高压管汇材料为例,进行了一系列疲劳试验,并基于试验数据,采用多种分布模型和不同S-N模型进行拟合分析,得出综合评价拟合能力最强的P-S-N模型。结果表明,该材料在中长疲劳寿命区,Weibull三参数模型在7级应力水平下综合评价能力最好;在存活率分别为50%、90%、99%、99.9%时,指数S-N模型的拟合系数均大于0.98,拟合能力最好。得出的P-S-N模型曲线可以为高压管汇的疲劳寿命以及安全设计提供依据。 展开更多
关键词 高压管汇材料 正态分布模型 Weibull分布模型 P-s-N模型 幂函数s-N模型 指数s-N模型
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基于哨兵函数和S变换的风力机叶片材料损伤特性研究
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作者 廖力达 舒王咏 +3 位作者 张芝铭 刘亮 冯飞 陈为强 《太阳能学报》 EI CAS CSCD 北大核心 2024年第7期656-663,共8页
利用声发射检测技术研究玻璃纤维增强环氧树脂复合材料的损伤特性,在此过程中,采用哨兵函数来表征该材料的损伤程度,并通过S变换和模糊C均值(FCM)聚类来分析声发射信号,从而获得材料的损伤特征。三点弯曲实验结束后对试件断口进行扫描... 利用声发射检测技术研究玻璃纤维增强环氧树脂复合材料的损伤特性,在此过程中,采用哨兵函数来表征该材料的损伤程度,并通过S变换和模糊C均值(FCM)聚类来分析声发射信号,从而获得材料的损伤特征。三点弯曲实验结束后对试件断口进行扫描电子显微镜(SEM)拍照来验证,可得:通过对SEM照片的分析得到基体开裂、纤维脱粘、分层破坏、纤维断裂4种损伤模式;对整个声发射事件进行哨兵函数分析,观察到试件在弯曲过程中哨兵函数曲线呈明显下降趋势;对依据哨兵函数划分的不同阶段的信号进行VMD降噪处理,然后采用S变换进行时频分析得到不同损伤的特征频率,最后采用FCM聚类进行验证。结果表明:哨兵函数值的突变可作为材料断裂的预警信号,材料损伤类型的识别可依据S变换的频率分布结果进行确定。 展开更多
关键词 风力机叶片 复合材料 声发射 损伤特性 哨兵函数 s变换
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Continuum Skyrme Hartree-Fock-Bogoliubov theory with Green’s function method for neutron-rich Ca,Ni,Zr,and Sn isotopes 被引量:3
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作者 En-Bo Huo Ke-Ran Li +2 位作者 Xiao-Ying Qu Ying Zhang Ting-Ting Sun 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第7期162-178,共17页
The possible exotic nuclear properties in the neutron-rich Ca,Ni,Zr,and Sn isotopes are examined with the continuum Skyrme Hartree-Fock-Bogoliubov theory in the framework of the Green’s function method.The pairing co... The possible exotic nuclear properties in the neutron-rich Ca,Ni,Zr,and Sn isotopes are examined with the continuum Skyrme Hartree-Fock-Bogoliubov theory in the framework of the Green’s function method.The pairing correlation,the couplings with the continuum,and the blocking effects for the unpaired nucleon in odd-A nuclei are properly treated.The Skyrme interaction SLy4 is adopted for the ph channel and the density-dependentinteraction is adopted for the pp chan-nel,which well reproduce the experimental two-neutron separation energies S_(2n)and one-neutron separation energies Sn.It is found that the criterion S_(n)>0 predicts a neutron drip line with neutron numbers much smaller than those for S_(2n)>0.Owing to the unpaired odd neutron,the neutron pairing energies−E_(pair)in odd-A nuclei are much lower than those in the neighbor-ing even-even nuclei.By investigating the single-particle structures,the possible halo structures in the neutron-rich Ca,Ni,and Sn isotopes are predicted,where sharp increases in the root-mean-square(rms)radii with significant deviations from the traditional rA^(1∕3)rule and diffuse spatial density distributions are observed.Analyzing the contributions of various partial waves to the total neutron densityρlj(r)∕ρ(r)reveals that the orbitals located around the Fermi surface-particularly those with small angular momenta-significantly affect the extended nuclear density and large rms radii.The number of neutrons Nλ(N_(0))occupying above the Fermi surfacen(continuum threshold)is discussed,whose evolution as a function of the mass number A in each isotope is consistent with that of the pairing energy,supporting the key role of the pairing correlation in halo phenomena. 展开更多
关键词 Neutron-rich nuclei Neutron halo skyrme Hartree-Fock-Bogoliubov theory Green’s function method
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Green's functions of two-dimensional piezoelectric quasicrystal in half-space and bimaterials 被引量:1
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作者 Xiaoyu FU Xiang MU +2 位作者 Jinming ZHANG Liangliang ZHANG Yang GAO 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第2期237-254,共18页
In this paper,we obtain Green’s functions of two-dimensional(2D)piezoelectric quasicrystal(PQC)in half-space and bimaterials.Based on the elastic theory of QCs,the Stroh formalism is used to derive the general soluti... In this paper,we obtain Green’s functions of two-dimensional(2D)piezoelectric quasicrystal(PQC)in half-space and bimaterials.Based on the elastic theory of QCs,the Stroh formalism is used to derive the general solutions of displacements and stresses.Then,we obtain the analytical solutions of half-space and bimaterial Green’s functions.Besides,the interfacial Green’s function for bimaterials is also obtained in the analytical form.Before numerical studies,a comparative study is carried out to validate the present solutions.Typical numerical examples are performed to investigate the effects of multi-physics loadings such as the line force,the line dislocation,the line charge,and the phason line force.As a result,the coupling effect among the phonon field,the phason field,and the electric field is prominent,and the butterfly-shaped contours are characteristic in 2D PQCs.In addition,the changes of material parameters cause variations in physical quantities to a certain degree. 展开更多
关键词 Green’s function two-dimensional(2D)piezoelectric quasicrystal(PQC) stroh formalism HALF-sPACE BIMATERIAL
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Neuroprotective effect of liraglutide and memantine in a rat model of Alzheimer’s disease 被引量:1
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作者 Duaa M.Bakhshwin Foziya W.Alhalabi +7 位作者 Mohamad Omar Barasheed Ahmed M.Bakhshwin Maha H.Jamal Mohammed A.Bazuhair Fatemah O.Kamel Rania M.Magadmi Zoheir A Damanhouri Samar M.Alsaggaf 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2024年第5期207-214,共8页
Objective:To assess the effect of memantine combined with liraglutide on aluminum chloride(AlCl_(3))and D-galactose(D-GAL)-induced neurotoxicity in rats.Methods:Male Wistar rats were divided into 5 groups of 5 animals... Objective:To assess the effect of memantine combined with liraglutide on aluminum chloride(AlCl_(3))and D-galactose(D-GAL)-induced neurotoxicity in rats.Methods:Male Wistar rats were divided into 5 groups of 5 animals each:the positive control,the negative control,the memantine-treated group,the liraglutide-treated group,and the combination group treated with memantine and liraglutide.AlCl_(3)and D-GAL were used to induce neurotoxicity.Behavioral tests,brain beta-amyloid protein,and oxidative stress biomarkers were evaluated.Results:The Morris water maze test indicated an enhanced memory in the combination group.Moreover,the combination treatment of liraglutide and memantine resulted in a remarkable reduction in the beta-amyloid protein level in the brain tissue.Neuronal inflammation and oxidative stress biomarkers were significantly reduced,and the levels of antioxidant parameters were enhanced.Conclusions:The combination of liraglutide and memantine exerts neuroprotective effects and enhances memory and cognitive functions in rats with Alzheimer’s disease. 展开更多
关键词 Alzheimer’s disease Cognitive function Glucagonlike peptide-1 LIRAGLUTIDE MEMANTINE
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GREEN'S FUNCTION AND THE POINTWISE BEHAVIORS OF THE VLASOV-POISSON-FOKKER-PLANCK SYSTEM
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作者 钟明溁 《Acta Mathematica Scientia》 SCIE CSCD 2023年第1期205-236,共32页
The pointwise space-time behaviors of the Green’s function and the global solution to the Vlasov-Poisson-Fokker-Planck(VPFP)system in three dimensional space are studied in this paper.It is shown that the Green’s fu... The pointwise space-time behaviors of the Green’s function and the global solution to the Vlasov-Poisson-Fokker-Planck(VPFP)system in three dimensional space are studied in this paper.It is shown that the Green’s function consists of the diffusion waves decaying exponentially in time but algebraically in space,and the singular kinetic waves which become smooth for all(t,x,v)when t>0.Furthermore,we establish the pointwise space-time behaviors of the global solution to the nonlinear VPFP system when the initial data is not necessarily smooth in terms of the Green’s function. 展开更多
关键词 Vlasov-Poisson-Fokker-Planck system Green’s function pointwise behavior spectrum structure
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Quantifyingα-diversity as a continuous function of location——a case study of a temperate forest
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作者 Peijian Shi Brady K.Quinn +2 位作者 Long Chen Jie Gao Julian Schrader 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第6期1683-1691,共9页
α-diversity describes species diversity at local scales.The Simpson’s and Shannon-Wiener indices are widely used to characterizeα-diversity based on species abundances within a fixed study site(e.g.,a quadrat or pl... α-diversity describes species diversity at local scales.The Simpson’s and Shannon-Wiener indices are widely used to characterizeα-diversity based on species abundances within a fixed study site(e.g.,a quadrat or plot).Although such indices provide overall diversity estimates that can be analyzed,their values are not spatially continuous nor applicable in theory to any point within the study region,and thus they cannot be treated as spatial covariates for analyses of other variables.Herein,we extended the Simpson’s and Shannon-Wiener indices to create point estimates ofα-diversity for any location based on spatially explicit species occurrences within different bandwidths(i.e.,radii,with the location of interest as the center).For an arbitrary point in the study region,species occurrences within the circle plotting the bandwidth were weighted according to their distance from the center using a tri-cube kernel function,with occurrences closer to the center having greater weight than more distant ones.These novel kernel-basedα-diversity indices were tested using a tree dataset from a 400 m×400 m study region comprising a 200 m×200 m core region surrounded by a 100-m width buffer zone.Our newly extendedα-diversity indices did not disagree qualitatively with the traditional indices,and the former were slightly lower than the latter by<2%at medium and large band widths.The present work demonstrates the feasibility of using kernel-basedα-diversity indices to estimate diversity at any location in the study region and allows them to be used as quantifiable spatial covariates or predictors for other dependent variables of interest in future ecological studies.Spatially continuousα-diversity indices are useful to compare and monitor species trends in space and time,which is valuable for conservation practitioners. 展开更多
关键词 Distance-based weighting Diversity continuum Kernel function shannon-Wiener index simpson’s index Tri-cube kernel
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Long-term radiofrequency electromagnetic fields exposure attenuates cognitive dysfunction in 5×FAD mice by regulating microglial function
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作者 Yeonghoon Son Hye-Jin Park +3 位作者 Ye Ji Jeong Hyung-Do Choi Nam Kim Hae-June Lee 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第11期2497-2503,共7页
We have previously found that long-term effects of exposure to radiofrequency electromagnetic fields in 5xFAD mice with severe late-stage Alzheimer’s disease reduced both amyloid-βdeposition and glial activation,inc... We have previously found that long-term effects of exposure to radiofrequency electromagnetic fields in 5xFAD mice with severe late-stage Alzheimer’s disease reduced both amyloid-βdeposition and glial activation,including microglia.To examine whether this therapeutic effect is due to the regulation of activated microglia,we analyzed mic roglial gene expression profiles and the existence of microglia in the brain in this study.5xFAD mice at the age of 1.5 months were assigned to sham-and radiofrequency electromagnetic fields-exposed groups and then animals were exposed to 1950 MHz radiofrequency electromagnetic fields at a specific absorption rate of 5 W/kg for 2 hours/day and 5 days/week for 6 months.We conducted behavioral tests including the object recognition and Y-maze tests and molecular and histopathological analysis of amyloid precursor protein/a myloid-beta metabolism in brain tissue.We confirmed that radiofrequency electromagnetic field exposure for 6 months ameliorated cognitive impairment and amyloid-βdeposition.The expression levels of Iba1(pan-microglial marker)and colony-stimulating factor 1 receptor(CSF1R;regulates microglial prolife ration)in the hippocampus in 5xFAD mice treated with radiofrequency electromagnetic fields were significantly reduced compared with those of the sham-exposed group.Subsequently,we analyzed the expression levels of genes related to mic rogliosis and microglial function in the radiofrequency electromagnetic fields-exposed group compared to those of a CSF1R inhibitor(PLX3397)-treated group.Both radiofrequency electromagnetic fields and PLX3397 suppressed the levels of genes related to microgliosis(Csf1r,CD68,and Ccl6)and pro-inflammatory cytokine interleukin-1β.N otably,the expression levels of genes related to mic roglial function,including Trem2,Fcgr1α,Ctss,and Spi1,were decreased after long-term radiofrequency electromagnetic field exposure,which was also observed in response to microglial suppression by PLX3397.These results showed that radiofrequency electromagnetic fields ameliorated amyloid-βpathology and cognitive impairment by suppressing amyloid-βdeposition-induced microgliosis and their key regulator,CSF1R. 展开更多
关键词 5×FAD Alzheimer’s disease CsF1R long term exposure microglial function NEUROINFLAMMATION radiofrequency electromagnetic fields therapeutic effect
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改进YOLOv7-tiny与D-S理论结合的实验室人员行为检测研究
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作者 杨永亮 曹敏 +4 位作者 徐凌桦 王霄 杨靖 王涛 冯平平 《现代电子技术》 北大核心 2024年第19期153-160,共8页
针对目前实验室场景缺少对人员行为检测的方法,且主流算法精度低、误检率高的问题,文中提出一种改进YOLOv7-tiny的人员行为检测算法,并通过多源信息融合,提高人员行为在实际实验室场景中的识别准确率。首先,在检测算法主干网络引入Ghost... 针对目前实验室场景缺少对人员行为检测的方法,且主流算法精度低、误检率高的问题,文中提出一种改进YOLOv7-tiny的人员行为检测算法,并通过多源信息融合,提高人员行为在实际实验室场景中的识别准确率。首先,在检测算法主干网络引入GhostNetV2轻量化网络,进一步降低模型计算量和复杂度;其次,在颈部网络嵌入改进后的CBAM_E注意力模块,加强目标重要特征的提取;再次,在预测端使用SIoU替换原有的损失函数,减少角度因素和边界框回归精度的影响。检测结果表明,相较于YOLOv7-tiny,文中算法精度提升10.08%,模型参数量和复杂度分别下降36.45%和46.76%。最后通过将检测数据与传感器采集数据运用D-S证据理论进行信息融合后发现,人员不规范行为检测的误检率得到有效降低。结果表明,该方法可实现对实验室人员不规范行为的有效检测。 展开更多
关键词 实验室场景 人员行为 YOLOv7-tiny 轻量化网络 注意力模块 损失函数 D-s证据理论 信息融合
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基于S函数的调节阀粘滞特性检测方法
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作者 李世伟 尚群立 《高技术通讯》 CAS 北大核心 2024年第4期406-412,共7页
调节阀粘滞特性引起的振荡是工业控制回路性能恶化的最常见来源。目前虽然已有许多检测调节阀粘滞特性的方法,但这些方法的复杂性或存在的缺陷限制着其在实际工况中的具体应用。本文提出了一种检测过程控制回路中调节阀粘滞故障的新方... 调节阀粘滞特性引起的振荡是工业控制回路性能恶化的最常见来源。目前虽然已有许多检测调节阀粘滞特性的方法,但这些方法的复杂性或存在的缺陷限制着其在实际工况中的具体应用。本文提出了一种检测过程控制回路中调节阀粘滞故障的新方法。该方法将控制器输出(OP)和过程变量(PV)的变化(ΔPV)在相平面图中所构成变化趋势与标准S函数进行对比,根据实际函数趋势与标准S函数间的差异计算相关系数,通过相关系数的数值具体得出调节阀中是否存在粘滞特性。仿真实例和实际工业数据分析实验验证了提出方法的有效性。 展开更多
关键词 调节阀 相关系数 s函数 粘滞检测
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N次幂下S-凸函数和其性质研究
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作者 刘明术 方宏彬 《池州学院学报》 2024年第3期6-9,共4页
以凸函数、S-凸函数、平方凸函数、平方S-凸函数的定义和性质为研究基础,根据从平方凸函数到平方S-凸函数的演变推进过程,采用了凸函数概念的代数不等式形式,给出了N次幂下S-凸函数的概念,并对其判别定理和性质进行了讨论,定义并证明了... 以凸函数、S-凸函数、平方凸函数、平方S-凸函数的定义和性质为研究基础,根据从平方凸函数到平方S-凸函数的演变推进过程,采用了凸函数概念的代数不等式形式,给出了N次幂下S-凸函数的概念,并对其判别定理和性质进行了讨论,定义并证明了N次幂下S-凸函数的Jensen型不等式。研究表明,N次幂下S-凸函数包含了凸函数、平方凸函数、平方S-凸函数的性质,是凸函数的一种广义凸函数的推广,开辟了全新的推广途径。 展开更多
关键词 JENsEN不等式 s-凸函数 平方凸函数 平方s-凸函数 判别定理
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基于Sigmoid函数的非对称式S型曲线机械臂加减速控制方法
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作者 杨传光 费胜巍 《东华大学学报(自然科学版)》 CAS 北大核心 2024年第5期118-126,共9页
机械臂广泛应用于制造、装配、搬运、码垛等方面,对提高生产力起着重要作用。为减小机械臂在运动过程中的振动和冲击,提高机械臂轨迹执行效率,提出一种非对称式S型曲线加减速控制方法。该方法通过在双段Sigmoid函数中插入直线段,构成加... 机械臂广泛应用于制造、装配、搬运、码垛等方面,对提高生产力起着重要作用。为减小机械臂在运动过程中的振动和冲击,提高机械臂轨迹执行效率,提出一种非对称式S型曲线加减速控制方法。该方法通过在双段Sigmoid函数中插入直线段,构成加加速度连续的运动学曲线。通过粒子群算法进行参数优化求解,无需反复确认每个时间段的存在性即可求出非对称约束下的曲线参数,并分别在关节空间和笛卡尔空间采用时间同步和位移同步方法使机械臂的运动轨迹更加协调自然。结果表明,相同条件下提出的方法比三角函数方法轨迹执行效率更高且加加速度仅为三角函数方法的55%。与梯形加加速度曲线相比,采用提出的方法规划的运动轨迹可减少35.7%的残余振动,验证了该方法的有效性。 展开更多
关键词 机械臂 非对称式s型曲线 轨迹规划 sIGMOID函数
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基于去偏置项SoftMax和紧致度量损失函数的牛脸识别方法
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作者 杨胜楠 赵建敏 +1 位作者 杨梅 赵宇飞 《黑龙江畜牧兽医》 CAS 北大核心 2024年第4期36-42,共7页
为了实现精准畜牧业生产及畜牧业保险理赔中牛只身份的准确识别,试验提出了基于去偏置项SoftMax和紧致度量损失函数的牛脸识别方法,即采用深度卷积神经网络(deep convolutional neural networks,DCNNs)模型提取特征,利用去偏置项SoftMa... 为了实现精准畜牧业生产及畜牧业保险理赔中牛只身份的准确识别,试验提出了基于去偏置项SoftMax和紧致度量损失函数的牛脸识别方法,即采用深度卷积神经网络(deep convolutional neural networks,DCNNs)模型提取特征,利用去偏置项SoftMax损失函数优化特征空间中的特征分布,提高特征线性可分辨性,解决特征归一化后在投影超平面上的重叠问题;采用紧致度量损失函数结合去偏置项SoftMax损失函数联合监督模型训练,使同类特征与类内特征的平均距离最小化,提高特征聚类的紧凑性和可辨识性,同时兼顾了类内样本分布的多样性;最后试验将本算法(去偏置项SoftMax和紧致度量损失函数联合监督算法)与ArcFace损失函数、标准SoftMax损失函数、去偏置项SoftMax损失函数、标准SoftMax损失函数结合紧致度量损失函数进行了性能对分分析。结果表明:本算法的识别准确率在所有模型中最高,为97.61%;且能对高相似度牛脸正确识别。说明基于去偏置项SoftMax和紧致度量损失函数的牛脸识别方法可满足牧场牛只身份识别要求。 展开更多
关键词 深度度量学习 身份识别 牛脸识别 去偏置项softMax损失函数 紧致度量损失函数 深度卷积神经网络
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