为有效降低体域网加速度数据远程获取系统功耗,提出一种用于低功耗的体域网加速度数据压缩感知处理框架。首先基于优化的稀疏二进制测量矩阵,线性投影压缩体域网传感节点的加速度数据,降低相应节点压缩算法的复杂性和数据传输量;在此基...为有效降低体域网加速度数据远程获取系统功耗,提出一种用于低功耗的体域网加速度数据压缩感知处理框架。首先基于优化的稀疏二进制测量矩阵,线性投影压缩体域网传感节点的加速度数据,降低相应节点压缩算法的复杂性和数据传输量;在此基础上,基于块稀疏贝叶斯学习模型,构建非稀疏加速度数据压缩感知重构算法,实现低功耗远程获取加速度数据。实验采用USC-HAD数据库的加速度数据,评估所提方法的有效性。结果表明,当优化稀疏二进制测量矩阵中每列非零元素个数为6、压缩率为50%时,能够获得与传统优化高斯随机矩阵、伯努利随机矩阵相同的压缩重构误差(约0.004 5);与一些传统的压缩感知重构算法相比,所提出的重构算法提高信噪比约17 d B,显著改善重构性能,可有效实现低功耗远程获取加速度数据。该方法有助于传感节点硬件简化设计,改善加速度数据重构性能,为构建低功耗体域网人体活动远程监测系统提供新的思路和方法。展开更多
The goal of the present paper is to expand already published works in the frame of＂Banded speed cosmology＂ （BSC）. In particular this paper gives validated values for physical quantities not so far investigated in ...The goal of the present paper is to expand already published works in the frame of＂Banded speed cosmology＂ （BSC）. In particular this paper gives validated values for physical quantities not so far investigated in previous publications, i.e., the number of individual physical entity in the universe, as well as the maximum value for acceleration. Validates values mean identical quantities from a numerical point of view obtained with different theoretical procedures, additionally compared with data based on NASA observations with Planck probe.展开更多
This paper presents the result of an experimental study on the compression of mechanical vibration signals. The signals are collected from both rotating and reciprocating machineries by the accelerometers and a data a...This paper presents the result of an experimental study on the compression of mechanical vibration signals. The signals are collected from both rotating and reciprocating machineries by the accelerometers and a data acquisition （DAQ） system. Four optimal sparse representation methods for compression have been considered including the method of frames （ MOF）, best orthogonal basis （ BOB）, matching pursuit （MP） and basis pursuit （BP）. Furthermore, several indicators including compression ratio （CR）, mean square error （MSE）, energy retained （ER） and Kurtosis are taken to evaluate the performance of the above methods. Experimental results show that MP outperforms other three methods.展开更多
In this article, the energy balance method is used to retrieve thermospheric mass density from CHAMP satellite precise orbit determination(POD) data during 2007–2009. The retrieved thermospheric mass densities are co...In this article, the energy balance method is used to retrieve thermospheric mass density from CHAMP satellite precise orbit determination(POD) data during 2007–2009. The retrieved thermospheric mass densities are compared with those from accelerometer data and an empirical model. The main conclusions are as follows:(1) Thermospheric mass density can be retrieved from POD data by the energy balance and semi-major axis decay methods, whose results are consistent.(2) The accuracy of the retrieved densities depends on the integration time period, and the optimal period for CHAMP density retrieval from POD data is about 20 minutes.(3) The energy balance method can be used to calibrate accelerometer data.(4) The accuracy of retrieving thermospheric density from POD data varies with satellite altitude and local time.展开更多
In this paper, we experimentally and theoretically study the resistance force that develops when a cylinder with a flat face colliding against dry quartzite sand. Observations from experimental data clearly show that ...In this paper, we experimentally and theoretically study the resistance force that develops when a cylinder with a flat face colliding against dry quartzite sand. Observations from experimental data clearly show that the acceleration curves are characterized by a double-peak structure. The first agitated peak can be attributed to a shock process where sand responds elastically, and the valley bottom in the double-peak structure is related to a limited plastic load when a fully plastic region is formed in the sand, while the second agitated peak corresponds to a the occurrence of the maximum of viscous force in a homogeneous developed bulk flow. We use slip line theory (SL) developed in plastic mechanics to capture the value at the valley bottom, adopt the double shearing theory (DS), together with a Local Rheological Constitutive Law (LRCL) suggested in this paper, to capture the drag force generated in a homogeneous bulk flow. Good agreements in the comparisons between numerical and experimental results support the characteristic resistance by the cylinder to predict granular states.展开更多
The solids acceleration length was investigated in a cold dense transport bed （0.10 m-IDx17 m-height） with three kinds of Silica sand. The solids circulation rate （Gs） was up to 954 kg/（m2s）. The effects of oper...The solids acceleration length was investigated in a cold dense transport bed （0.10 m-IDx17 m-height） with three kinds of Silica sand. The solids circulation rate （Gs） was up to 954 kg/（m2s）. The effects of operating conditions, particle properties, and riser structures on the solids acceleration length were investigated under high Gs conditions, with the effect of riser height non-negligible. The solids acceleration length increased with the increase of the riser height. Based on the experimental data, an empirical correlation was proposed to predict the solids acceleration length. Predictions of the correlation were in good agreement with the experimental data in this work and those from the literature over a wide range of Gs （18~954 kg/（m2s））.展开更多
Inspired by the f（R） non-linear massive gravity, we propose a new kind of modified gravity model, namely f（T） non-linear massive gravity, by adding the dRGT mass term reformulated in the vierbein formalism, to th...Inspired by the f（R） non-linear massive gravity, we propose a new kind of modified gravity model, namely f（T） non-linear massive gravity, by adding the dRGT mass term reformulated in the vierbein formalism, to the f（T） theory. We then investigate the cosmological evolution of f（T） massive gravity, and constrain it by using the latest observational data. We find that it slightly favors a crossing of the phantom divide line from the quintessence-like phase （wae 〉 -1） to the phantom-like one （wae 〈 -1） as redshiff decreases.展开更多
文摘为有效降低体域网加速度数据远程获取系统功耗,提出一种用于低功耗的体域网加速度数据压缩感知处理框架。首先基于优化的稀疏二进制测量矩阵,线性投影压缩体域网传感节点的加速度数据,降低相应节点压缩算法的复杂性和数据传输量;在此基础上,基于块稀疏贝叶斯学习模型,构建非稀疏加速度数据压缩感知重构算法,实现低功耗远程获取加速度数据。实验采用USC-HAD数据库的加速度数据,评估所提方法的有效性。结果表明,当优化稀疏二进制测量矩阵中每列非零元素个数为6、压缩率为50%时,能够获得与传统优化高斯随机矩阵、伯努利随机矩阵相同的压缩重构误差(约0.004 5);与一些传统的压缩感知重构算法相比,所提出的重构算法提高信噪比约17 d B,显著改善重构性能,可有效实现低功耗远程获取加速度数据。该方法有助于传感节点硬件简化设计,改善加速度数据重构性能,为构建低功耗体域网人体活动远程监测系统提供新的思路和方法。
文摘The goal of the present paper is to expand already published works in the frame of＂Banded speed cosmology＂ （BSC）. In particular this paper gives validated values for physical quantities not so far investigated in previous publications, i.e., the number of individual physical entity in the universe, as well as the maximum value for acceleration. Validates values mean identical quantities from a numerical point of view obtained with different theoretical procedures, additionally compared with data based on NASA observations with Planck probe.
基金Supported by the National Natural Science Foundation of China （No. 50635010）.
文摘This paper presents the result of an experimental study on the compression of mechanical vibration signals. The signals are collected from both rotating and reciprocating machineries by the accelerometers and a data acquisition （DAQ） system. Four optimal sparse representation methods for compression have been considered including the method of frames （ MOF）, best orthogonal basis （ BOB）, matching pursuit （MP） and basis pursuit （BP）. Furthermore, several indicators including compression ratio （CR）, mean square error （MSE）, energy retained （ER） and Kurtosis are taken to evaluate the performance of the above methods. Experimental results show that MP outperforms other three methods.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41325017 & 41274158)
文摘In this article, the energy balance method is used to retrieve thermospheric mass density from CHAMP satellite precise orbit determination(POD) data during 2007–2009. The retrieved thermospheric mass densities are compared with those from accelerometer data and an empirical model. The main conclusions are as follows:(1) Thermospheric mass density can be retrieved from POD data by the energy balance and semi-major axis decay methods, whose results are consistent.(2) The accuracy of the retrieved densities depends on the integration time period, and the optimal period for CHAMP density retrieval from POD data is about 20 minutes.(3) The energy balance method can be used to calibrate accelerometer data.(4) The accuracy of retrieving thermospheric density from POD data varies with satellite altitude and local time.
基金the National Natural Science Foundation ofChina (Grant No. 11132001)
文摘In this paper, we experimentally and theoretically study the resistance force that develops when a cylinder with a flat face colliding against dry quartzite sand. Observations from experimental data clearly show that the acceleration curves are characterized by a double-peak structure. The first agitated peak can be attributed to a shock process where sand responds elastically, and the valley bottom in the double-peak structure is related to a limited plastic load when a fully plastic region is formed in the sand, while the second agitated peak corresponds to a the occurrence of the maximum of viscous force in a homogeneous developed bulk flow. We use slip line theory (SL) developed in plastic mechanics to capture the value at the valley bottom, adopt the double shearing theory (DS), together with a Local Rheological Constitutive Law (LRCL) suggested in this paper, to capture the drag force generated in a homogeneous bulk flow. Good agreements in the comparisons between numerical and experimental results support the characteristic resistance by the cylinder to predict granular states.
基金the financial support of National High-tech Research and Development Program of China (863 Program) (No. 2006AA05A103)that of Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences (No. KGCX2-YW-348)
文摘The solids acceleration length was investigated in a cold dense transport bed （0.10 m-IDx17 m-height） with three kinds of Silica sand. The solids circulation rate （Gs） was up to 954 kg/（m2s）. The effects of operating conditions, particle properties, and riser structures on the solids acceleration length were investigated under high Gs conditions, with the effect of riser height non-negligible. The solids acceleration length increased with the increase of the riser height. Based on the experimental data, an empirical correlation was proposed to predict the solids acceleration length. Predictions of the correlation were in good agreement with the experimental data in this work and those from the literature over a wide range of Gs （18~954 kg/（m2s））.
基金Supported by National Natural Science Foundation of China under Grant Nos.11175016 and 10905005New Century Excellent Talents in University under Grant No.NCET-11-0790
文摘Inspired by the f（R） non-linear massive gravity, we propose a new kind of modified gravity model, namely f（T） non-linear massive gravity, by adding the dRGT mass term reformulated in the vierbein formalism, to the f（T） theory. We then investigate the cosmological evolution of f（T） massive gravity, and constrain it by using the latest observational data. We find that it slightly favors a crossing of the phantom divide line from the quintessence-like phase （wae 〉 -1） to the phantom-like one （wae 〈 -1） as redshiff decreases.
