Timely identification and treatment of medical conditions could facilitate faster recovery and better health.Existing systems address this issue using custom-built sensors,which are invasive and difficult to generaliz...Timely identification and treatment of medical conditions could facilitate faster recovery and better health.Existing systems address this issue using custom-built sensors,which are invasive and difficult to generalize.A low-complexity scalable process is proposed to detect and identify medical conditions from 2D skeletal movements on video feed data.Minimal set of features relevant to distinguish medical conditions:AMF,PVF and GDF are derived from skeletal data on sampled frames across the entire action.The AMF(angular motion features)are derived to capture the angular motion of limbs during a specific action.The relative position of joints is represented by PVF(positional variation features).GDF(global displacement features)identifies the direction of overall skeletal movement.The discriminative capability of these features is illustrated by their variance across time for different actions.The classification of medical conditions is approached in two stages.In the first stage,a low-complexity binary LSTM classifier is trained to distinguish visual medical conditions from general human actions.As part of stage 2,a multi-class LSTM classifier is trained to identify the exact medical condition from a given set of visually interpretable medical conditions.The proposed features are extracted from the 2D skeletal data of NTU RGB+D and then used to train the binary and multi-class LSTM classifiers.The binary and multi-class classifiers observed average F1 scores of 77%and 73%,respectively,while the overall system produced an average F1 score of 69%and a weighted average F1 score of 80%.The multi-class classifier is found to utilize 10 to 100 times fewer parameters than existing 2D CNN-based models while producing similar levels of accuracy.展开更多
The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-n...The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio fuzes.To solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is proposed.First,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)signal.Then,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for classification.The DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical algorithms.The trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.展开更多
A series of test simulations are performed to evaluate the impact of satellite-derived meteorological data on numerical typhoon track prediction. Geostationary meteorological satellite (GMS-5) and NOAA's TIROS ope...A series of test simulations are performed to evaluate the impact of satellite-derived meteorological data on numerical typhoon track prediction. Geostationary meteorological satellite (GMS-5) and NOAA's TIROS operational vertical sounder (TOVS) observations are used in the experiments. A two-dimensional variation assimilation scheme is developed to assimilate the satellite data directly into the Penn State-NCAR nonhydrostatic meteorological model (MM5). Three-dimensional objective analyses fields based on T213 results and routine observations are employed as the background fields of the initialization. The comparisons of the simulated typhoon tracks are also carried out, which correspond respectively to the initialization scheme with two-dimensional variation (2D - Var), three-dimensional observational nudging and direct assimilation of satellite data. It is found that, comparing with the experiments without satellite data assimilation, the first two assimilation schemes lead to significant improvements on typhoon track prediction. Track errors reduce by 18 % at 12 h for 2D - Var and from about 16 % at 24 h to about 35 % at 48 h for observational nudging. The simulated results based on assimilating different kinds of satellite data are also compared.展开更多
利用水力模型软件Info Works ICM建立广州市FY路2D排水模型,分析评估现状管道水力运行状况,找出内涝的原因,制定有针对性的解决方案,并利用水力模型对设计方案进行校核,保证方案的合理性和可行性。现通过实例介绍2D排水模型在城市排水...利用水力模型软件Info Works ICM建立广州市FY路2D排水模型,分析评估现状管道水力运行状况,找出内涝的原因,制定有针对性的解决方案,并利用水力模型对设计方案进行校核,保证方案的合理性和可行性。现通过实例介绍2D排水模型在城市排水工程中的应用方法和具体流程,可为其他地区模型应用提供参考。展开更多
研究了两部2D雷达组网中的目标定位估计和定位精度问题。为考虑地球曲率对目标定位精度的影响,提出了两雷达站组网中基于实际地球椭球模型的几何交叉定位与数据融合相结合的方法,建立了两部雷达观测定位几何模型,推导了定位方程和精度...研究了两部2D雷达组网中的目标定位估计和定位精度问题。为考虑地球曲率对目标定位精度的影响,提出了两雷达站组网中基于实际地球椭球模型的几何交叉定位与数据融合相结合的方法,建立了两部雷达观测定位几何模型,推导了定位方程和精度估计公式并进行了误差分析。仿真分析表明,在选择更为实际的观测模型的前提下,利用几何定位与数据融合方法不但改善了两雷达的定位性能,而且根据定位几何精度因子(geometricaldilution of precision,GDOP)图的特点,选择相应的定位雷达,提高了雷达站组合的几何定位精度。展开更多
文摘Timely identification and treatment of medical conditions could facilitate faster recovery and better health.Existing systems address this issue using custom-built sensors,which are invasive and difficult to generalize.A low-complexity scalable process is proposed to detect and identify medical conditions from 2D skeletal movements on video feed data.Minimal set of features relevant to distinguish medical conditions:AMF,PVF and GDF are derived from skeletal data on sampled frames across the entire action.The AMF(angular motion features)are derived to capture the angular motion of limbs during a specific action.The relative position of joints is represented by PVF(positional variation features).GDF(global displacement features)identifies the direction of overall skeletal movement.The discriminative capability of these features is illustrated by their variance across time for different actions.The classification of medical conditions is approached in two stages.In the first stage,a low-complexity binary LSTM classifier is trained to distinguish visual medical conditions from general human actions.As part of stage 2,a multi-class LSTM classifier is trained to identify the exact medical condition from a given set of visually interpretable medical conditions.The proposed features are extracted from the 2D skeletal data of NTU RGB+D and then used to train the binary and multi-class LSTM classifiers.The binary and multi-class classifiers observed average F1 scores of 77%and 73%,respectively,while the overall system produced an average F1 score of 69%and a weighted average F1 score of 80%.The multi-class classifier is found to utilize 10 to 100 times fewer parameters than existing 2D CNN-based models while producing similar levels of accuracy.
基金National Natural Science Foundation of China under Grant No.61973037China Postdoctoral Science Foundation 2022M720419 to provide fund for conducting experiments。
文摘The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio fuzes.To solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is proposed.First,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)signal.Then,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for classification.The DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical algorithms.The trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.
文摘A series of test simulations are performed to evaluate the impact of satellite-derived meteorological data on numerical typhoon track prediction. Geostationary meteorological satellite (GMS-5) and NOAA's TIROS operational vertical sounder (TOVS) observations are used in the experiments. A two-dimensional variation assimilation scheme is developed to assimilate the satellite data directly into the Penn State-NCAR nonhydrostatic meteorological model (MM5). Three-dimensional objective analyses fields based on T213 results and routine observations are employed as the background fields of the initialization. The comparisons of the simulated typhoon tracks are also carried out, which correspond respectively to the initialization scheme with two-dimensional variation (2D - Var), three-dimensional observational nudging and direct assimilation of satellite data. It is found that, comparing with the experiments without satellite data assimilation, the first two assimilation schemes lead to significant improvements on typhoon track prediction. Track errors reduce by 18 % at 12 h for 2D - Var and from about 16 % at 24 h to about 35 % at 48 h for observational nudging. The simulated results based on assimilating different kinds of satellite data are also compared.
文摘利用水力模型软件Info Works ICM建立广州市FY路2D排水模型,分析评估现状管道水力运行状况,找出内涝的原因,制定有针对性的解决方案,并利用水力模型对设计方案进行校核,保证方案的合理性和可行性。现通过实例介绍2D排水模型在城市排水工程中的应用方法和具体流程,可为其他地区模型应用提供参考。
文摘研究了两部2D雷达组网中的目标定位估计和定位精度问题。为考虑地球曲率对目标定位精度的影响,提出了两雷达站组网中基于实际地球椭球模型的几何交叉定位与数据融合相结合的方法,建立了两部雷达观测定位几何模型,推导了定位方程和精度估计公式并进行了误差分析。仿真分析表明,在选择更为实际的观测模型的前提下,利用几何定位与数据融合方法不但改善了两雷达的定位性能,而且根据定位几何精度因子(geometricaldilution of precision,GDOP)图的特点,选择相应的定位雷达,提高了雷达站组合的几何定位精度。
