Aiming at the application background of sliding spotlight mode Synthetic Aperture Radar (SAR) ima... more Aiming at the application background of sliding spotlight mode Synthetic Aperture Radar (SAR) imaging processing, this paper builds a System-on-a-Programmable-Chip-based (SoPC-based) sliding spotlight mode SAR imaging verification system, which uses software and hardware collaborative design method to complete algorithm-to-hardware mapping and can quickly and truly perform in FPGA or ASIC. Finally, we analyzed the implementation of the imaging prototype system and the imaging results. For the generation of correlation factors, this paper hierarchically decomposes the factor generation operation to realize the time division multiplexing of the operation unit, in order to reduce resource consumption. At the same time, a variable point Fast Fourier Transformation (FFT) processor based on a variable radix-23 multiplexing butterfly unit is designed and implemented. Combining these two parts with other modules enables the entire sliding spotlight mode imaging process. On the basis of keeping the error of the result small, the overall resource consumption is greatly reduced. The 1024~32768 point FFT is implemented by the top-level configurable method, and the operation delay is reduced by more than 20% compared with the Xilinx FFT IP core. The final imaging time is reduced to seconds, and the imaging results meet the requirements. Subsequent compatibility design for other SAR imaging modes also can be achieved.
Journal of the University of Shanghai for Science and Technology, 2008
Under two body-postures (supine and 45° reclining) the blood pulse signal on toe was detected via... more Under two body-postures (supine and 45° reclining) the blood pulse signal on toe was detected via non-invasive photoplethysmography technique while the lower limb was passively raised in different height. The regulations of blood pulse volume and lower limb height were found and their relation was described through curves in figures.
Monitoring of mixed venous oxygen saturation (SvO(2)) is currently performed using invasive fibre... more Monitoring of mixed venous oxygen saturation (SvO(2)) is currently performed using invasive fibre-optic catheters. This procedure is not without risk as complications may arise from catheterization. This paper describes an alternative, non-invasive method of monitoring peripheral venous oxygen saturation (SxvO(2)) which, although it cannot replace pulmonary artery catheters, can serve as an adjunct/early warning indicator of when there is an imbalance in oxygen supply and demand. The technique requires the generation of an artificial venous pulse at the finger, thereby causing modulation of the venous blood volume within the digit. The blood volume changes are monitored using an optical sensor. Just as pulse oximetry utilizes the natural arterial pulse to perform a spectrophotometric analysis of the peripheral blood in order to estimate the arterial blood oxygen saturation, the proposed venous oximetry technique uses the artificially generated venous pulse to estimate SxvO(2). A prototype device was tested in a pilot study with patients undergoing heart surgery. Data from this study support the notion that the method is capable of tracking haemodynamic changes and suggests the technique is worthy of further development and evaluation.
2019 IEEE International Conference on Signal, Information and Data Processing (ICSIDP), Dec 1, 2019
In the multi-mode SAR imaging processing targeted in this paper, the FFT requirement granularity ... more In the multi-mode SAR imaging processing targeted in this paper, the FFT requirement granularity ranges from 1024 to 32768. Therefore, this paper mainly describes the method of implementing reconfigurable and variable-level FFT units using radix-2k, By analyzing and comparing the radix 2k algorithm, the radix-23 is selected as the basis of the single-channel FFT butterfly, and the range of the point representation is extended by the butterfly transformation downward compatible with the radix-22/radix-2. This paper realizes an architecture of the single channel delay feedback variable-point, high precision FFT processor.
We study the dependence of total secondary electron yield (SEY) of micro-porous silver surface on... more We study the dependence of total secondary electron yield (SEY) of micro-porous silver surface on incident angle of primary electron. First, we produce regular and random micro-porous surfaces on silver plated aluminium samples by photolithography pattern process and direct chemical etching method, respectively. Second, we study the dependence of the SEY characteristics of these surfaces on the primary electron incident angle from 0° to 60°. The experimental results show that micro-porous surface with large porosity can suppress SEY effectively either for normal incidence or oblique incidence. The maximum SEY of the directly chemical etched sample can reach a 45% reduction relative to the original flat sample. We also show the anomalous experimental phenomenon that the SEY of directly chemical etched sample with large porosity does not increase with incident angle. Third, we explain the complicated SEY dependence on incident angle qualitatively by the secondary electron trapping effect in micro-pores as well as the Monte Carlo simulation based on phenomenological model of secondary electron emission. Finally, we suggest a third order polynomial formula to describe the SEY dependence on incident angle which will be useful in particle simulation. In total, we demonstrate that micro-porous surface with large porosity is effective in SEY suppression under both normal and oblique incidence and thus the proposed direct chemical etching method is prospective in related areas such as multipactor improvement.
A little explored area of human activity recognition (HAR) is in people operating in relation to ... more A little explored area of human activity recognition (HAR) is in people operating in relation to extreme environments, e.g., mountaineers. In these contexts, the ability to accurately identify activities, alongside other data streams, has the potential to prevent death and serious negative health events to the operators. This study aimed to address this user group and investigate factors associated with the placement, number, and combination of accelerometer sensors. Eight participants (age = 25.0 ± 7 years) wore 17 accelerometers simultaneously during lab-based simulated mountaineering activities, under a range of equipment and loading conditions. Initially, a selection of machine learning techniques was tested. Secondly, a comprehensive analysis of all possible combinations of the 17 accelerometers was performed to identify the optimum number of sensors, and their respective body locations. Finally, the impact of activity-specific equipment on the classifier accuracy was explored....
We study secondary electron yield (SEY) suppression for metal materials using a roughened surface... more We study secondary electron yield (SEY) suppression for metal materials using a roughened surface with a micro-porous array. First, we perform a Monte Carlo simulation of the electron trajectory in a single cylindrical well using a phenomenological model of secondary electron emission and the SEY suppression efficiency of a micro-porous array. The simulation results show that the SEY of a roughened surface is affected significantly by the aspect ratio of the micro-pores and the surface porosity of the metal plate. Then, to verify the simulation results, we produce a micro-porous array on metal plates using photolithography and measure their SEYs. We show that the micro-porous array structure can efficiently suppress the SEY of metal materials, and the measurements agree quantitatively with the corresponding simulation results. Finally, we derive an analytical formula to evaluate easily the SEY suppression efficiency of the Ag micro-porous array. In total, the micro-porous array prop...
Aiming at the application background of sliding spotlight mode Synthetic Aperture Radar (SAR) ima... more Aiming at the application background of sliding spotlight mode Synthetic Aperture Radar (SAR) imaging processing, this paper builds a System-on-a-Programmable-Chip-based (SoPC-based) sliding spotlight mode SAR imaging verification system, which uses software and hardware collaborative design method to complete algorithm-to-hardware mapping and can quickly and truly perform in FPGA or ASIC. Finally, we analyzed the implementation of the imaging prototype system and the imaging results. For the generation of correlation factors, this paper hierarchically decomposes the factor generation operation to realize the time division multiplexing of the operation unit, in order to reduce resource consumption. At the same time, a variable point Fast Fourier Transformation (FFT) processor based on a variable radix-23 multiplexing butterfly unit is designed and implemented. Combining these two parts with other modules enables the entire sliding spotlight mode imaging process. On the basis of keeping the error of the result small, the overall resource consumption is greatly reduced. The 1024~32768 point FFT is implemented by the top-level configurable method, and the operation delay is reduced by more than 20% compared with the Xilinx FFT IP core. The final imaging time is reduced to seconds, and the imaging results meet the requirements. Subsequent compatibility design for other SAR imaging modes also can be achieved.
Journal of the University of Shanghai for Science and Technology, 2008
Under two body-postures (supine and 45° reclining) the blood pulse signal on toe was detected via... more Under two body-postures (supine and 45° reclining) the blood pulse signal on toe was detected via non-invasive photoplethysmography technique while the lower limb was passively raised in different height. The regulations of blood pulse volume and lower limb height were found and their relation was described through curves in figures.
Monitoring of mixed venous oxygen saturation (SvO(2)) is currently performed using invasive fibre... more Monitoring of mixed venous oxygen saturation (SvO(2)) is currently performed using invasive fibre-optic catheters. This procedure is not without risk as complications may arise from catheterization. This paper describes an alternative, non-invasive method of monitoring peripheral venous oxygen saturation (SxvO(2)) which, although it cannot replace pulmonary artery catheters, can serve as an adjunct/early warning indicator of when there is an imbalance in oxygen supply and demand. The technique requires the generation of an artificial venous pulse at the finger, thereby causing modulation of the venous blood volume within the digit. The blood volume changes are monitored using an optical sensor. Just as pulse oximetry utilizes the natural arterial pulse to perform a spectrophotometric analysis of the peripheral blood in order to estimate the arterial blood oxygen saturation, the proposed venous oximetry technique uses the artificially generated venous pulse to estimate SxvO(2). A prototype device was tested in a pilot study with patients undergoing heart surgery. Data from this study support the notion that the method is capable of tracking haemodynamic changes and suggests the technique is worthy of further development and evaluation.
2019 IEEE International Conference on Signal, Information and Data Processing (ICSIDP), Dec 1, 2019
In the multi-mode SAR imaging processing targeted in this paper, the FFT requirement granularity ... more In the multi-mode SAR imaging processing targeted in this paper, the FFT requirement granularity ranges from 1024 to 32768. Therefore, this paper mainly describes the method of implementing reconfigurable and variable-level FFT units using radix-2k, By analyzing and comparing the radix 2k algorithm, the radix-23 is selected as the basis of the single-channel FFT butterfly, and the range of the point representation is extended by the butterfly transformation downward compatible with the radix-22/radix-2. This paper realizes an architecture of the single channel delay feedback variable-point, high precision FFT processor.
We study the dependence of total secondary electron yield (SEY) of micro-porous silver surface on... more We study the dependence of total secondary electron yield (SEY) of micro-porous silver surface on incident angle of primary electron. First, we produce regular and random micro-porous surfaces on silver plated aluminium samples by photolithography pattern process and direct chemical etching method, respectively. Second, we study the dependence of the SEY characteristics of these surfaces on the primary electron incident angle from 0° to 60°. The experimental results show that micro-porous surface with large porosity can suppress SEY effectively either for normal incidence or oblique incidence. The maximum SEY of the directly chemical etched sample can reach a 45% reduction relative to the original flat sample. We also show the anomalous experimental phenomenon that the SEY of directly chemical etched sample with large porosity does not increase with incident angle. Third, we explain the complicated SEY dependence on incident angle qualitatively by the secondary electron trapping effect in micro-pores as well as the Monte Carlo simulation based on phenomenological model of secondary electron emission. Finally, we suggest a third order polynomial formula to describe the SEY dependence on incident angle which will be useful in particle simulation. In total, we demonstrate that micro-porous surface with large porosity is effective in SEY suppression under both normal and oblique incidence and thus the proposed direct chemical etching method is prospective in related areas such as multipactor improvement.
A little explored area of human activity recognition (HAR) is in people operating in relation to ... more A little explored area of human activity recognition (HAR) is in people operating in relation to extreme environments, e.g., mountaineers. In these contexts, the ability to accurately identify activities, alongside other data streams, has the potential to prevent death and serious negative health events to the operators. This study aimed to address this user group and investigate factors associated with the placement, number, and combination of accelerometer sensors. Eight participants (age = 25.0 ± 7 years) wore 17 accelerometers simultaneously during lab-based simulated mountaineering activities, under a range of equipment and loading conditions. Initially, a selection of machine learning techniques was tested. Secondly, a comprehensive analysis of all possible combinations of the 17 accelerometers was performed to identify the optimum number of sensors, and their respective body locations. Finally, the impact of activity-specific equipment on the classifier accuracy was explored....
We study secondary electron yield (SEY) suppression for metal materials using a roughened surface... more We study secondary electron yield (SEY) suppression for metal materials using a roughened surface with a micro-porous array. First, we perform a Monte Carlo simulation of the electron trajectory in a single cylindrical well using a phenomenological model of secondary electron emission and the SEY suppression efficiency of a micro-porous array. The simulation results show that the SEY of a roughened surface is affected significantly by the aspect ratio of the micro-pores and the surface porosity of the metal plate. Then, to verify the simulation results, we produce a micro-porous array on metal plates using photolithography and measure their SEYs. We show that the micro-porous array structure can efficiently suppress the SEY of metal materials, and the measurements agree quantitatively with the corresponding simulation results. Finally, we derive an analytical formula to evaluate easily the SEY suppression efficiency of the Ag micro-porous array. In total, the micro-porous array prop...
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