OBJECTIVE To find a promising candidate for anti-Alzheimer disease(AD)with multiple targets in multiple pathways.METHODS A series of classifiers were constructed for predicting the active compounds against 51 key targ...OBJECTIVE To find a promising candidate for anti-Alzheimer disease(AD)with multiple targets in multiple pathways.METHODS A series of classifiers were constructed for predicting the active compounds against 51 key targets toward Alzheimer disease(AD)using the multitargetquantitative structure-activity relationships(mt-QSAR)method.While drug screening assays were established to evaluate the predicted active molecules.In addition,various cellular models and animal models related with AD were set up to further study the effects of the active compounds.RESULTS A system for the discovery of Multitarget-Directed Ligands against AD was set up and applied,the predicted active compounds were validated by the drug screening assays,and several active compounds with multiple targets were discovered.Among them,DL0410 exerted high activity on H3R,α7n ACh R,ACh E and ERα,also displayed the most significant effect in improving the ability of memory and learning in several AD animal models.The study on its action mechanisms showed that it′s effect may partially through increasing neurotransmitter,inhibiting oxidative emergency,inhibiting the expression of APP,and promoting long-term potentiation.Besides,DL0410 is of more safety than the first-line clinical medicines.CONCLUSION DL0410 is a promising candidate for further development for AD treatment.展开更多
A multiple targets detection method based on spatial smoothing （MTDSS） is proposed to solve the problem of the source number estimation under the colored noise background. The forward and backward smoothing based on...A multiple targets detection method based on spatial smoothing （MTDSS） is proposed to solve the problem of the source number estimation under the colored noise background. The forward and backward smoothing based on auxiliary vectors which are received data on some specific elements is computed. By the spatial smoothing with auxiliary vectors, the correlated signals are decorrelated, and the colored noise is partially alleviated. The correlation matrix formed from the cross correlations between subarray data and auxiliary vectors is computed. By exploring the second-order statistics property of the covariance matrix, a threshold based on Gerschgorin radii of the smoothing correlation matrix is set to estimate the number of sources. Simulations and experimental results validate that MTDSS has an effective performance under the condition of the colored noise background and coherent sources, and MTDSS is robust with the correlated factor of signals and noise.展开更多
Multiple maneuvedng targets signal processing in high frequency radar is challenging due to the following difficulties： the interference between signals is severe because of significant spread of the target Doppler s...Multiple maneuvedng targets signal processing in high frequency radar is challenging due to the following difficulties： the interference between signals is severe because of significant spread of the target Doppler spectrum, the low signal to clutter ratio （SCR） environment degrades the performance of signal process- ing algorithms. This paper addresses this challenging problem by using an S2-method and an adaptive clutter rejection scheme. The proposed S2-method improves the S-method by eliminating inter- ference between signals, and thus it enables multi-target signals to be reconstructed individually. The proposed adaptive clutter rejec- tion scheme is based on an adaptive notch filter, which is designed according to the envelop of the clutter spectrum. Experiments with simulated targets added into radar sea clutter echo and real air target data illustrate the effectiveness of the proposed method.展开更多
In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussi...In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussian surface function is constructed first by the measurements, and it is used to define the GSM via a mapping function. We then integrate the GSM with the probability hypothesis density（PHD） filter, the Bayesian recursion formulas of GSM-PHD are derived and the Gaussian mixture implementation is employed to obtain the closed-form solutions. Moreover, the estimated shapes are designed to guide the measurement set sub-partition, which can cope with the problem of the spatially close target tracking. Simulation results show that the proposed algorithm can effectively estimate irregular target shapes and exhibit good robustness in cross extended target tracking.展开更多
A credible method of calculating the detection threshold is presented for the multiple target situations, which appear frequently in the lower Doppler velocity region during the surveillance of sea with HF ground wave...A credible method of calculating the detection threshold is presented for the multiple target situations, which appear frequently in the lower Doppler velocity region during the surveillance of sea with HF ground wave radar. This method defines a whole-peak-outlier elimination （WPOE） criterion, which is based on in-peak-samples correlation of each target echo spectra, to trim off the target signals and abnormal disturbances with great amplitude from the complex spectra. Therefore, cleaned background noise samples are obtained to improve the accuracy and reliability of noise level estimation. When the background noise is nonhomogeneous, the detection samples are limited and often occupied heavily with outliers. In this case, the problem that the detection threshold is overvalued can be solved. In applications on experimental data, it is verified that this method can reduce the miss alarm rate of signal detection effectively in multiple target situations as well as make the adaptability of the detector better.展开更多
To mitigate the deleterious effects of clutter and jammer, modern radars have adopted adaptive processing techniques such as constant false alarm rate(CFAR) detectors which are widely used to prevent clutter and noise...To mitigate the deleterious effects of clutter and jammer, modern radars have adopted adaptive processing techniques such as constant false alarm rate(CFAR) detectors which are widely used to prevent clutter and noise interference from saturating the radar’s display and preventing targets from being obscured.This paper concerns with the detection analysis of the novel version of CFAR schemes(cell-averaging generalized trimmed-mean,CATM) in the presence of additional outlying targets other than the target under research. The spurious targets as well as the tested one are assumed to be fluctuating in accordance with the χ~2-model with two-degrees of freedom. In this situation, the processor performance is enclosed by the swerling models(SWI and SWII). Between these bounds, there is an important class of target fluctuation which is known as moderately fluctuating targets. The detection of this class has many practical applications. Structure of the CATM detector is described briefly. Detection performances for optimal, CAM, CA, trimmed-mean(TM) and ordered-statistic(OS) CFAR strategies have been analyzed and compared for desired probability of false alarm and determined size of the reference window. False alarm rate performance of these processors has been evaluated for different strengths of interfering signal and the effect of correlation among the target returns on the detection and false alarm performances has also been studied. Our numerical results show that, with a proper choice of trimming parameters,the novel model CAM presents an ideal detection performance outweighing that of the Neyman-Pearson detector on condition that the tested target obeys the SWII model in its fluctuation. Although the new models CAS and CAM can be treated as special cases of the CATM algorithm, their multi-target performance is modest even it has an enhancement relative to that of the classical CAcheme. Additionally, they fail to maintain the false alarm rate constant when the operating environment is of type target multiplicity. Moreover, the non-coherent integration of M pulses ameliorates the processor performance either it operates in homogeneous or multi-target environment.展开更多
Collocated multiple input multiple output(MIMO)radar,which has agile multi-beam working mode,can offer enhanced multiple targets tracking(MTT)ability.In detail,it can illuminate different targets simultaneously with m...Collocated multiple input multiple output(MIMO)radar,which has agile multi-beam working mode,can offer enhanced multiple targets tracking(MTT)ability.In detail,it can illuminate different targets simultaneously with multi-beam or one wide beam among multi-beam,providing greater degree of freedom in system resource control.An adaptive time-space resource and waveform control optimization model for the collocated MIMO radar with simultaneous multi-beam is proposed in this paper.The aim of the proposed scheme is to improve the overall tracking accuracy and meanwhile minimize the resource consumption under the guarantee of effective targets detection.A resource and waveform control algorithm which integrates the genetic algorithm(GA)is proposed to solve the optimization problem.The optimal transmitting waveform parameters,system sampling period,sub-array number,binary radar tracking parameterχ_i(t_k),transmitting energy and multi-beam direction vector combination are chosen adaptively,where the first one realizes the waveform control and the latter five realize the timespace resource allocation.Simulation results demonstrate the effectiveness of the proposed control method.展开更多
This study proposes a method for uniformly revolving swarm robots to entrap multiple targets,which is based on a gene regulatory network,an adaptive decision mechanism,and an improved Vicsek-model.Using the gene regul...This study proposes a method for uniformly revolving swarm robots to entrap multiple targets,which is based on a gene regulatory network,an adaptive decision mechanism,and an improved Vicsek-model.Using the gene regulatory network method,the robots can generate entrapping patterns according to the environmental input,including the positions of the targets and obstacles.Next,an adaptive decision mechanism is proposed,allowing each robot to choose the most well-adapted capture point on the pattern,based on its environment.The robots employ an improved Vicsek-model to maneuver to the planned capture point smoothly,without colliding with other robots or obstacles.The proposed decision mechanism,combined with the improved Vicsek-model,can form a uniform entrapment shape and create a revolving effect around targets while entrapping them.This study also enables swarm robots,with an adaptive pattern formation,to entrap multiple targets in complex environments.Swarm robots can be deployed in the military field of unmanned aerial vehicles’(UAVs)entrapping multiple targets.Simulation experiments demonstrate the feasibility and superiority of the proposed gene regulatory network method.展开更多
Panax Ginseng has been used for thousands of years in traditional Chinese medicine(TCM)as a tonic to improver stamina and vitality.Ginsenoside Rg1(Rg1),a saponin extracted from Panax ginseng,is considered one of the m...Panax Ginseng has been used for thousands of years in traditional Chinese medicine(TCM)as a tonic to improver stamina and vitality.Ginsenoside Rg1(Rg1),a saponin extracted from Panax ginseng,is considered one of the most potent pharmacological candidates among TCM.In various diseases related to nervous system,Rg1 has shown excellent pharmacological activities.①Stroke:Rg1 has been well documented to be effective against ischemic/reperfusion(I/R)neuronal injury.A systematic review and meta-analysis revealed a marked efficacy of Rg1 in experi⁃mental acute ischemic stroke,as manifested by its ability to reduce infract volume and improve neurological score.The protective effects of Rg1 were abolished by injecting of AAV-HIF-miR-144-shRNA into the predicted ischemic penumbra.②Depression:In addition,Rg1 showed antidepressive effects in chronic unpredictable mild stress(CUMS)model of depression and in gonadectomized(GDX)model of neuroendocrine disturbance.Rg1 displayed antidepressant activity through the modulation of HPA and HPG axis,markedly alleviated depression-like behavior in rats.Long-term Rg1 treat⁃ment of CUS-exposed rats also significantly prevented the decrease in dye diffusion and improved the ultrastructure of astrocyte gap junctions in the PFC.Rg1 upregulated Cx43 expression in PFC reduced by CUS exposure,indicating beneficial effects on the functional activity of gap junction channels in the brain.③Parkinson disease(PD):Oral treatment with Rg1 significantly attenuated high MPTP-induced mortality,behavior defects,loss of dopamine neurons and abnormal unltrastructure changes in SNpc.It regulated MPTP-induced reactive astrocytes and microglia and decreased the release of cytokines such as TNF-alpha and IL-1βin SNpc.Rg1 also alleviated the unusual MPTP-induced increase in oligomeric,phosphorylated and disease-relatedα-synuclein in SNpc.④Alzheimer disease(AD):Okadaic acid(OKA)intracerebroventricular injection induced memory impairment,including changes in the ability of orientation navigate,spatial probe and relearning memory in behavioral test of Morris water maze(MWM).OKA treated rats showed memory impair⁃ment including increasing of phospho-tau,decreasing of phospho-GSK3βand the formation ofβ-amyloid in special brain regions,which were reversed by Rg1.The possible neuroprotective mechanism might be that Rg1 decreases OKAinduced memory impairment through GSK3β/tau signaling pathway and/or attenuating Aβformation.Meanwhile,Rg1 activated ERK/MAPK pathway by CaMKIIα,and the activation of CREB was not only dependent on ERK induced by Rg1.Additionally,Rg1 inhibited microglial activation by suppressing Iba1 expression.Rg1 inhibited the inflammation mediated by LPS through suppressing NF-κB and MAPK pathway,which provided the explanation for its therapeutic ef⁃fect on neurodegenerative diseases.展开更多
Aimed at solving the distance and vetocity decoupling problems of a moving target in LFMCW radar signal processing, a multiple repetition frequency waveform is adopted and a Doppler frequency duster algorithm is propo...Aimed at solving the distance and vetocity decoupling problems of a moving target in LFMCW radar signal processing, a multiple repetition frequency waveform is adopted and a Doppler frequency duster algorithm is proposed, which is capable of recovering true velocity form the coupled velocity estimation directly. For the resolution of multiple targets, a match algorithm based on mean square error is also proposed. The combination of the above two methods realizes distance and velocity decoupling of multiple moving targets. The result of simulation verifies the effectiveness of the methods, the velocity estimation performance of DFS algorithm is improved by 2.5 dB compared with Chinese remiander theorem.展开更多
An imaging algorithm based on compressed sensing（CS） for the multi-ship motion target is presented. In order to reduce the quantity of data transmission in searching the ships on a large sea area, both range and azi...An imaging algorithm based on compressed sensing（CS） for the multi-ship motion target is presented. In order to reduce the quantity of data transmission in searching the ships on a large sea area, both range and azimuth of the moving ship targets are converted into sparse representation under certain signal basis. The signal reconstruction algorithm based on CS at a distant calculation station, and the Keystone and fractional Fourier transform（FRFT） algorithm are used to compensate range migration and obtain Doppler frequency. When the sea ships satisfy the sparsity, the algorithm can obtain higher resolution in both range and azimuth than the conventional imaging algorithm. Some simulations are performed to verify the reliability and stability.展开更多
As to the fact that it is difficult to obtain analytical form of optimal sampling density and tracking performance of standard particle probability hypothesis density(P-PHD) filter would decline when clustering algori...As to the fact that it is difficult to obtain analytical form of optimal sampling density and tracking performance of standard particle probability hypothesis density(P-PHD) filter would decline when clustering algorithm is used to extract target states,a free clustering optimal P-PHD(FCO-P-PHD) filter is proposed.This method can lead to obtainment of analytical form of optimal sampling density of P-PHD filter and realization of optimal P-PHD filter without use of clustering algorithms in extraction target states.Besides,as sate extraction method in FCO-P-PHD filter is coupled with the process of obtaining analytical form for optimal sampling density,through decoupling process,a new single-sensor free clustering state extraction method is proposed.By combining this method with standard P-PHD filter,FC-P-PHD filter can be obtained,which significantly improves the tracking performance of P-PHD filter.In the end,the effectiveness of proposed algorithms and their advantages over other algorithms are validated through several simulation experiments.展开更多
Usually, only the Cramer-Rao lower bound （CRLB） of single target is taken into consideration in the state estimate of passive tracking systems. As for the case of multitarget, there are few works done due to its com...Usually, only the Cramer-Rao lower bound （CRLB） of single target is taken into consideration in the state estimate of passive tracking systems. As for the case of multitarget, there are few works done due to its complexity. The recursion formula of the posterior Cramer-Rao lower bound （PCRLB） in multitarget bearings-only tracking with the three kinds of data association is presented. Meanwhile, computer simulation is carried out for data association. The final result shows that the accuracy probability of data association has an important impact on the PCRLB.展开更多
基金supported by National Great Science and Technology Projects(2014ZX09507003-002,2013ZX09402203 and 2013ZX09508104001002)CAMS Initiative for Innovative Medicine(CAMS-I2M)(2016-I2M-3-007)National Natural Science Foundation of China(81673480)
文摘OBJECTIVE To find a promising candidate for anti-Alzheimer disease(AD)with multiple targets in multiple pathways.METHODS A series of classifiers were constructed for predicting the active compounds against 51 key targets toward Alzheimer disease(AD)using the multitargetquantitative structure-activity relationships(mt-QSAR)method.While drug screening assays were established to evaluate the predicted active molecules.In addition,various cellular models and animal models related with AD were set up to further study the effects of the active compounds.RESULTS A system for the discovery of Multitarget-Directed Ligands against AD was set up and applied,the predicted active compounds were validated by the drug screening assays,and several active compounds with multiple targets were discovered.Among them,DL0410 exerted high activity on H3R,α7n ACh R,ACh E and ERα,also displayed the most significant effect in improving the ability of memory and learning in several AD animal models.The study on its action mechanisms showed that it′s effect may partially through increasing neurotransmitter,inhibiting oxidative emergency,inhibiting the expression of APP,and promoting long-term potentiation.Besides,DL0410 is of more safety than the first-line clinical medicines.CONCLUSION DL0410 is a promising candidate for further development for AD treatment.
基金supported by the National Natural Science Foundation of China (61001153)the Fundamental Research Program of Northwestern Polytechnical University (JC20100223)
文摘A multiple targets detection method based on spatial smoothing （MTDSS） is proposed to solve the problem of the source number estimation under the colored noise background. The forward and backward smoothing based on auxiliary vectors which are received data on some specific elements is computed. By the spatial smoothing with auxiliary vectors, the correlated signals are decorrelated, and the colored noise is partially alleviated. The correlation matrix formed from the cross correlations between subarray data and auxiliary vectors is computed. By exploring the second-order statistics property of the covariance matrix, a threshold based on Gerschgorin radii of the smoothing correlation matrix is set to estimate the number of sources. Simulations and experimental results validate that MTDSS has an effective performance under the condition of the colored noise background and coherent sources, and MTDSS is robust with the correlated factor of signals and noise.
基金supported by the State Key Program of National Natural Science Foundation of China(61032011)
文摘Multiple maneuvedng targets signal processing in high frequency radar is challenging due to the following difficulties： the interference between signals is severe because of significant spread of the target Doppler spectrum, the low signal to clutter ratio （SCR） environment degrades the performance of signal process- ing algorithms. This paper addresses this challenging problem by using an S2-method and an adaptive clutter rejection scheme. The proposed S2-method improves the S-method by eliminating inter- ference between signals, and thus it enables multi-target signals to be reconstructed individually. The proposed adaptive clutter rejec- tion scheme is based on an adaptive notch filter, which is designed according to the envelop of the clutter spectrum. Experiments with simulated targets added into radar sea clutter echo and real air target data illustrate the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China(6130501761304264+1 种基金61402203)the Natural Science Foundation of Jiangsu Province(BK20130154)
文摘In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussian surface function is constructed first by the measurements, and it is used to define the GSM via a mapping function. We then integrate the GSM with the probability hypothesis density（PHD） filter, the Bayesian recursion formulas of GSM-PHD are derived and the Gaussian mixture implementation is employed to obtain the closed-form solutions. Moreover, the estimated shapes are designed to guide the measurement set sub-partition, which can cope with the problem of the spatially close target tracking. Simulation results show that the proposed algorithm can effectively estimate irregular target shapes and exhibit good robustness in cross extended target tracking.
文摘A credible method of calculating the detection threshold is presented for the multiple target situations, which appear frequently in the lower Doppler velocity region during the surveillance of sea with HF ground wave radar. This method defines a whole-peak-outlier elimination （WPOE） criterion, which is based on in-peak-samples correlation of each target echo spectra, to trim off the target signals and abnormal disturbances with great amplitude from the complex spectra. Therefore, cleaned background noise samples are obtained to improve the accuracy and reliability of noise level estimation. When the background noise is nonhomogeneous, the detection samples are limited and often occupied heavily with outliers. In this case, the problem that the detection threshold is overvalued can be solved. In applications on experimental data, it is verified that this method can reduce the miss alarm rate of signal detection effectively in multiple target situations as well as make the adaptability of the detector better.
文摘To mitigate the deleterious effects of clutter and jammer, modern radars have adopted adaptive processing techniques such as constant false alarm rate(CFAR) detectors which are widely used to prevent clutter and noise interference from saturating the radar’s display and preventing targets from being obscured.This paper concerns with the detection analysis of the novel version of CFAR schemes(cell-averaging generalized trimmed-mean,CATM) in the presence of additional outlying targets other than the target under research. The spurious targets as well as the tested one are assumed to be fluctuating in accordance with the χ~2-model with two-degrees of freedom. In this situation, the processor performance is enclosed by the swerling models(SWI and SWII). Between these bounds, there is an important class of target fluctuation which is known as moderately fluctuating targets. The detection of this class has many practical applications. Structure of the CATM detector is described briefly. Detection performances for optimal, CAM, CA, trimmed-mean(TM) and ordered-statistic(OS) CFAR strategies have been analyzed and compared for desired probability of false alarm and determined size of the reference window. False alarm rate performance of these processors has been evaluated for different strengths of interfering signal and the effect of correlation among the target returns on the detection and false alarm performances has also been studied. Our numerical results show that, with a proper choice of trimming parameters,the novel model CAM presents an ideal detection performance outweighing that of the Neyman-Pearson detector on condition that the tested target obeys the SWII model in its fluctuation. Although the new models CAS and CAM can be treated as special cases of the CATM algorithm, their multi-target performance is modest even it has an enhancement relative to that of the classical CAcheme. Additionally, they fail to maintain the false alarm rate constant when the operating environment is of type target multiplicity. Moreover, the non-coherent integration of M pulses ameliorates the processor performance either it operates in homogeneous or multi-target environment.
基金supported by the National Natural Science Foundation of China(61671137)。
文摘Collocated multiple input multiple output(MIMO)radar,which has agile multi-beam working mode,can offer enhanced multiple targets tracking(MTT)ability.In detail,it can illuminate different targets simultaneously with multi-beam or one wide beam among multi-beam,providing greater degree of freedom in system resource control.An adaptive time-space resource and waveform control optimization model for the collocated MIMO radar with simultaneous multi-beam is proposed in this paper.The aim of the proposed scheme is to improve the overall tracking accuracy and meanwhile minimize the resource consumption under the guarantee of effective targets detection.A resource and waveform control algorithm which integrates the genetic algorithm(GA)is proposed to solve the optimization problem.The optimal transmitting waveform parameters,system sampling period,sub-array number,binary radar tracking parameterχ_i(t_k),transmitting energy and multi-beam direction vector combination are chosen adaptively,where the first one realizes the waveform control and the latter five realize the timespace resource allocation.Simulation results demonstrate the effectiveness of the proposed control method.
基金funded by the National Natural Science Foundation of China(62176147)the Science and Technology Planning Project of Guangdong Province of China,the State Key Lab of Digital Manufacturing Equipment and Technology(DMETKF2019020)the National Defense Technology Innovation Special Zone Project(193-A14-226-01-01)。
文摘This study proposes a method for uniformly revolving swarm robots to entrap multiple targets,which is based on a gene regulatory network,an adaptive decision mechanism,and an improved Vicsek-model.Using the gene regulatory network method,the robots can generate entrapping patterns according to the environmental input,including the positions of the targets and obstacles.Next,an adaptive decision mechanism is proposed,allowing each robot to choose the most well-adapted capture point on the pattern,based on its environment.The robots employ an improved Vicsek-model to maneuver to the planned capture point smoothly,without colliding with other robots or obstacles.The proposed decision mechanism,combined with the improved Vicsek-model,can form a uniform entrapment shape and create a revolving effect around targets while entrapping them.This study also enables swarm robots,with an adaptive pattern formation,to entrap multiple targets in complex environments.Swarm robots can be deployed in the military field of unmanned aerial vehicles’(UAVs)entrapping multiple targets.Simulation experiments demonstrate the feasibility and superiority of the proposed gene regulatory network method.
基金National Natural Sciences Foundation of China(8187302681473373+4 种基金8173009681603316U1402221)；CAMS Innovation Fund for Medical Sciences(CIFMS)(2016-I2M-1-004)PUMC Graduate Education and Teaching Reform Project(10023201600801)
文摘Panax Ginseng has been used for thousands of years in traditional Chinese medicine(TCM)as a tonic to improver stamina and vitality.Ginsenoside Rg1(Rg1),a saponin extracted from Panax ginseng,is considered one of the most potent pharmacological candidates among TCM.In various diseases related to nervous system,Rg1 has shown excellent pharmacological activities.①Stroke:Rg1 has been well documented to be effective against ischemic/reperfusion(I/R)neuronal injury.A systematic review and meta-analysis revealed a marked efficacy of Rg1 in experi⁃mental acute ischemic stroke,as manifested by its ability to reduce infract volume and improve neurological score.The protective effects of Rg1 were abolished by injecting of AAV-HIF-miR-144-shRNA into the predicted ischemic penumbra.②Depression:In addition,Rg1 showed antidepressive effects in chronic unpredictable mild stress(CUMS)model of depression and in gonadectomized(GDX)model of neuroendocrine disturbance.Rg1 displayed antidepressant activity through the modulation of HPA and HPG axis,markedly alleviated depression-like behavior in rats.Long-term Rg1 treat⁃ment of CUS-exposed rats also significantly prevented the decrease in dye diffusion and improved the ultrastructure of astrocyte gap junctions in the PFC.Rg1 upregulated Cx43 expression in PFC reduced by CUS exposure,indicating beneficial effects on the functional activity of gap junction channels in the brain.③Parkinson disease(PD):Oral treatment with Rg1 significantly attenuated high MPTP-induced mortality,behavior defects,loss of dopamine neurons and abnormal unltrastructure changes in SNpc.It regulated MPTP-induced reactive astrocytes and microglia and decreased the release of cytokines such as TNF-alpha and IL-1βin SNpc.Rg1 also alleviated the unusual MPTP-induced increase in oligomeric,phosphorylated and disease-relatedα-synuclein in SNpc.④Alzheimer disease(AD):Okadaic acid(OKA)intracerebroventricular injection induced memory impairment,including changes in the ability of orientation navigate,spatial probe and relearning memory in behavioral test of Morris water maze(MWM).OKA treated rats showed memory impair⁃ment including increasing of phospho-tau,decreasing of phospho-GSK3βand the formation ofβ-amyloid in special brain regions,which were reversed by Rg1.The possible neuroprotective mechanism might be that Rg1 decreases OKAinduced memory impairment through GSK3β/tau signaling pathway and/or attenuating Aβformation.Meanwhile,Rg1 activated ERK/MAPK pathway by CaMKIIα,and the activation of CREB was not only dependent on ERK induced by Rg1.Additionally,Rg1 inhibited microglial activation by suppressing Iba1 expression.Rg1 inhibited the inflammation mediated by LPS through suppressing NF-κB and MAPK pathway,which provided the explanation for its therapeutic ef⁃fect on neurodegenerative diseases.
文摘Aimed at solving the distance and vetocity decoupling problems of a moving target in LFMCW radar signal processing, a multiple repetition frequency waveform is adopted and a Doppler frequency duster algorithm is proposed, which is capable of recovering true velocity form the coupled velocity estimation directly. For the resolution of multiple targets, a match algorithm based on mean square error is also proposed. The combination of the above two methods realizes distance and velocity decoupling of multiple moving targets. The result of simulation verifies the effectiveness of the methods, the velocity estimation performance of DFS algorithm is improved by 2.5 dB compared with Chinese remiander theorem.
基金supported by the National Natural Science Foundation of China(61271342)
文摘An imaging algorithm based on compressed sensing（CS） for the multi-ship motion target is presented. In order to reduce the quantity of data transmission in searching the ships on a large sea area, both range and azimuth of the moving ship targets are converted into sparse representation under certain signal basis. The signal reconstruction algorithm based on CS at a distant calculation station, and the Keystone and fractional Fourier transform（FRFT） algorithm are used to compensate range migration and obtain Doppler frequency. When the sea ships satisfy the sparsity, the algorithm can obtain higher resolution in both range and azimuth than the conventional imaging algorithm. Some simulations are performed to verify the reliability and stability.
文摘As to the fact that it is difficult to obtain analytical form of optimal sampling density and tracking performance of standard particle probability hypothesis density(P-PHD) filter would decline when clustering algorithm is used to extract target states,a free clustering optimal P-PHD(FCO-P-PHD) filter is proposed.This method can lead to obtainment of analytical form of optimal sampling density of P-PHD filter and realization of optimal P-PHD filter without use of clustering algorithms in extraction target states.Besides,as sate extraction method in FCO-P-PHD filter is coupled with the process of obtaining analytical form for optimal sampling density,through decoupling process,a new single-sensor free clustering state extraction method is proposed.By combining this method with standard P-PHD filter,FC-P-PHD filter can be obtained,which significantly improves the tracking performance of P-PHD filter.In the end,the effectiveness of proposed algorithms and their advantages over other algorithms are validated through several simulation experiments.
文摘Usually, only the Cramer-Rao lower bound （CRLB） of single target is taken into consideration in the state estimate of passive tracking systems. As for the case of multitarget, there are few works done due to its complexity. The recursion formula of the posterior Cramer-Rao lower bound （PCRLB） in multitarget bearings-only tracking with the three kinds of data association is presented. Meanwhile, computer simulation is carried out for data association. The final result shows that the accuracy probability of data association has an important impact on the PCRLB.
