With the evolution of DC distribution networks from traditional radial topologies to more complex multi-branch structures,the number of measurement points supporting synchronous communication remains relatively limite...With the evolution of DC distribution networks from traditional radial topologies to more complex multi-branch structures,the number of measurement points supporting synchronous communication remains relatively limited.This poses challenges for conventional fault distance estimation methods,which are often tailored to simple topologies and are thus difficult to apply to large-scale,multi-node DC networks.To address this,a fault distance estimation method based on sparse measurement of high-frequency electrical quantities is proposed in this paper.First,a preliminary fault line identification model based on compressed sensing is constructed to effectively narrow the fault search range and improve localization efficiency.Then,leveraging the high-frequency impedance characteristics and the voltage-current relationship of electrical quantities,a fault distance estimation approach based on high-frequency measurements from both ends of a line is designed.This enables accurate distance estimation even when the measurement devices are not directly placed at both ends of the faulted line,overcoming the dependence on specific sensor placement inherent in traditional methods.Finally,to further enhance accuracy,an optimization model based on minimizing the high-frequency voltage error at the fault point is introduced to reduce estimation error.Simulation results demonstrate that the proposed method achieves a fault distance estimation error of less than 1%under normal conditions,and maintains good performance even under adverse scenarios.展开更多
Speckle decorrelation algorithm is a method using decorrelation curves to estimate the distance between two neighbor- ing ultrasound images. In this paper, we propose a new method to obtain specific decorrelation curv...Speckle decorrelation algorithm is a method using decorrelation curves to estimate the distance between two neighbor- ing ultrasound images. In this paper, we propose a new method to obtain specific decorrelation curves for distance estimation. First, several datasets of synthetic ultrasound （US） images are obtained by scanning different scatters. Second, based on the US datasets, we compute low-order moments and the elevational decorrelation curves. Finally, low-order moments are used to classify different scattering conditions. The suitable decorrelation curves can be acquired when the scattering style has been determined. With these steps, the relationship between low order moments and the decor- relation curves is established by the scattering conditions. This relationship proves to be efficient and applicable in the experiment section. The decorrelation curves chosen according to the rela- tionship also perform well in the distance estimation test.展开更多
The movement of a robotic arm in the working environment requires efficient and adequate motion planning.The procedure of collision detection based on the object geometry is crucial to plan the motion trajectories,and...The movement of a robotic arm in the working environment requires efficient and adequate motion planning.The procedure of collision detection based on the object geometry is crucial to plan the motion trajectories,and usually requires intensive resource and considerable time.Many learning-based collision detection schemes have been developed to improve the efficiency of collision detection.However,current learning-based collision detection methods are either not accurate enough or prone to low efficiency.We propose a simple,yet highly accurate collision distance estimator,a spatial information assisted distance estimator,i.e.,SPADE,in which spatial information of both robotic arms and obstacles are encoded by multiple encoders.With evaluation in both static and dynamic environments,our model shows higher prediction accuracy than multiple baselines,and higher accuracy can be corroborated by experiment with our model under the premise of equal inference efficiency.In addition,our model shows better robustness than baseline in real-world path planning.展开更多
An in-situ optically transparent thin-layer microscopic FTIR spectroelectro- chemical cell was constructed.Using this cell,we characterize a concentration-distance profile in the electrochemical diffusion thin-layer b...An in-situ optically transparent thin-layer microscopic FTIR spectroelectro- chemical cell was constructed.Using this cell,we characterize a concentration-distance profile in the electrochemical diffusion thin-layer by in-situ adjusting the focal point at different distances to the electrode surface.展开更多
Control performance monitoring has attracted great attention in both academia and industry over the past two decades. However, most research efforts have been devoted to the performance monitoring of linear control sy...Control performance monitoring has attracted great attention in both academia and industry over the past two decades. However, most research efforts have been devoted to the performance monitoring of linear control systems, without considering the pervasive nonlinearities(e.g. valve stiction) present in most industrial control systems. In this work, a novel probability distribution distance based index is proposed to monitor the performance of non-linear control systems. The proposed method uses Hellinger distance to evaluate change of control system performance. Several simulation examples are given to illustrate the effectiveness of the proposed method.展开更多
This paper evaluates different characteristics for earthquake early warning. The scaling relationships between magnitude, epicenter distance and calculated parameters are derived from earthquake event data fi＇om USGS...This paper evaluates different characteristics for earthquake early warning. The scaling relationships between magnitude, epicenter distance and calculated parameters are derived from earthquake event data fi＇om USGS. The standard STA/LTA method is modified by adding two new parameters to eliminate the effects of the spike-type noise and small pulsetype noise ahead of the onset of the P-wave. After the detection of the P-wave, the algorithm extracts 12 kinds of parameters from the first 3 seconds of the P-wave. Then stepwise regression analysis of these parameters is performed to estimate the epicentral distance and magnitude. Six different parameters are selected to estimate the epicentral distance, and the median error for all 419 estimates is 16.5 krn. Four parameters are optimally combined to estimate the magnitude, and the mean error for all events is 0.0 magnitude units, with a standard deviation of 0.5. Finally, based on the estimation results, additional work is proposed to improve the accuracy of the results.展开更多
In recent years, high-resolution video has developed rapidly and widescreen smart devices have become popular. We present an Android application called WeWatch that enables high-resolution video to be shared across tw...In recent years, high-resolution video has developed rapidly and widescreen smart devices have become popular. We present an Android application called WeWatch that enables high-resolution video to be shared across two mobile devices when they are close to each other. This concept has its inspiration in machine-to-machine connections in the Internet of Things （loT）. We ensure that the two parts of the video are the same size over both screens and are synchronous. Further, a user can play, pause, or stop the video by moving one device a certain distance from the other. We decide on appropriate distances through experimentation. We implemented WeWatch on Android operating system and then optimize Watch so battery consumption is reduced. The user experience provided by WeWatch was evaluated by students through a questionnaire, and the reviews indicated that WeWatch does improve the viewing experience.展开更多
This paper described an improved underwater confrontation simulation method of naval amphibious operational training system. The initial position of submarine forces on the enemy is generated automatically, and the at...This paper described an improved underwater confrontation simulation method of naval amphibious operational training system. The initial position of submarine forces on the enemy is generated automatically, and the attacking distance model of torpedoes is established based on the kinematics theory, which is more flexible and reasonable to judge the launch condition compared to traditional method. The two kinds of confrontation behavior models on the enemy submarine are created to depict its tactical action from the defensive to the offensive as well as the contrary, ensuring that operational style is simulated more comprehensively and properly. The existing motion trajectory estimation and collision detection algorithms on operational platforms are also improved to reduce the iteration error and further enhance the detection accuracy of target hit.展开更多
Hypervelocity impact(HVI)vibration source identification and localization have found wide applications in many fields,such as manned spacecraft protection and machine tool collision damage detection and localization.I...Hypervelocity impact(HVI)vibration source identification and localization have found wide applications in many fields,such as manned spacecraft protection and machine tool collision damage detection and localization.In this paper,we study the synchrosqueezed transform(SST)algorithm and the texture color distribution(TCD)based HVI source identification and localization using impact images.The extracted SST and TCD image features are fused for HVI image representation.To achieve more accurate detection and localization,the optimal selective stitching features OSSST+TCD are obtained by correlating and evaluating the similarity between the sample label and each dimension of the features.Popular conventional classification and regression models are merged by voting and stacking to achieve the final detection and localization.To demonstrate the effectiveness of the proposed algorithm,the HVI data recorded from three kinds of high-speed bullet striking on an aluminum alloy plate is used for experimentation.The experimental results show that the proposed HVI identification and localization algorithm is more accurate than other algorithms.Finally,based on sensor distribution,an accurate four-circle centroid localization algorithm is developed for HVI source coordinate localization.展开更多
基金National Natural Science Foundation of China, grant number 52177074.
文摘With the evolution of DC distribution networks from traditional radial topologies to more complex multi-branch structures,the number of measurement points supporting synchronous communication remains relatively limited.This poses challenges for conventional fault distance estimation methods,which are often tailored to simple topologies and are thus difficult to apply to large-scale,multi-node DC networks.To address this,a fault distance estimation method based on sparse measurement of high-frequency electrical quantities is proposed in this paper.First,a preliminary fault line identification model based on compressed sensing is constructed to effectively narrow the fault search range and improve localization efficiency.Then,leveraging the high-frequency impedance characteristics and the voltage-current relationship of electrical quantities,a fault distance estimation approach based on high-frequency measurements from both ends of a line is designed.This enables accurate distance estimation even when the measurement devices are not directly placed at both ends of the faulted line,overcoming the dependence on specific sensor placement inherent in traditional methods.Finally,to further enhance accuracy,an optimization model based on minimizing the high-frequency voltage error at the fault point is introduced to reduce estimation error.Simulation results demonstrate that the proposed method achieves a fault distance estimation error of less than 1%under normal conditions,and maintains good performance even under adverse scenarios.
基金Supported by the National Basic Research Program of China(2011CB707900)
文摘Speckle decorrelation algorithm is a method using decorrelation curves to estimate the distance between two neighbor- ing ultrasound images. In this paper, we propose a new method to obtain specific decorrelation curves for distance estimation. First, several datasets of synthetic ultrasound （US） images are obtained by scanning different scatters. Second, based on the US datasets, we compute low-order moments and the elevational decorrelation curves. Finally, low-order moments are used to classify different scattering conditions. The suitable decorrelation curves can be acquired when the scattering style has been determined. With these steps, the relationship between low order moments and the decor- relation curves is established by the scattering conditions. This relationship proves to be efficient and applicable in the experiment section. The decorrelation curves chosen according to the rela- tionship also perform well in the distance estimation test.
文摘The movement of a robotic arm in the working environment requires efficient and adequate motion planning.The procedure of collision detection based on the object geometry is crucial to plan the motion trajectories,and usually requires intensive resource and considerable time.Many learning-based collision detection schemes have been developed to improve the efficiency of collision detection.However,current learning-based collision detection methods are either not accurate enough or prone to low efficiency.We propose a simple,yet highly accurate collision distance estimator,a spatial information assisted distance estimator,i.e.,SPADE,in which spatial information of both robotic arms and obstacles are encoded by multiple encoders.With evaluation in both static and dynamic environments,our model shows higher prediction accuracy than multiple baselines,and higher accuracy can be corroborated by experiment with our model under the premise of equal inference efficiency.In addition,our model shows better robustness than baseline in real-world path planning.
文摘An in-situ optically transparent thin-layer microscopic FTIR spectroelectro- chemical cell was constructed.Using this cell,we characterize a concentration-distance profile in the electrochemical diffusion thin-layer by in-situ adjusting the focal point at different distances to the electrode surface.
基金Supported by the National Natural Science Foundation of China(61134007,61203157)the National Science Fund for Outstanding Young Scholars(61222303)+1 种基金the Fundamental Research Funds for the Central Universities(22A20151405)Shanghai R&D Platform Construction Program(13DZ2295300)
文摘Control performance monitoring has attracted great attention in both academia and industry over the past two decades. However, most research efforts have been devoted to the performance monitoring of linear control systems, without considering the pervasive nonlinearities(e.g. valve stiction) present in most industrial control systems. In this work, a novel probability distribution distance based index is proposed to monitor the performance of non-linear control systems. The proposed method uses Hellinger distance to evaluate change of control system performance. Several simulation examples are given to illustrate the effectiveness of the proposed method.
文摘This paper evaluates different characteristics for earthquake early warning. The scaling relationships between magnitude, epicenter distance and calculated parameters are derived from earthquake event data fi＇om USGS. The standard STA/LTA method is modified by adding two new parameters to eliminate the effects of the spike-type noise and small pulsetype noise ahead of the onset of the P-wave. After the detection of the P-wave, the algorithm extracts 12 kinds of parameters from the first 3 seconds of the P-wave. Then stepwise regression analysis of these parameters is performed to estimate the epicentral distance and magnitude. Six different parameters are selected to estimate the epicentral distance, and the median error for all 419 estimates is 16.5 krn. Four parameters are optimally combined to estimate the magnitude, and the mean error for all events is 0.0 magnitude units, with a standard deviation of 0.5. Finally, based on the estimation results, additional work is proposed to improve the accuracy of the results.
基金supported by the National Natural Science Funds of China under Grant No.61300034the National High-Tech Research&Development Program of China("863"Program)under Grant No.2012AA011103+1 种基金the Key Science and Technology Program of Anhui Province under Grant No.1206c0805039,a start-up fund for Huangshan Mountain Scholars(Outstanding Young Talents Program of Hefei University of Technology)under Grant No.405-037070
文摘In recent years, high-resolution video has developed rapidly and widescreen smart devices have become popular. We present an Android application called WeWatch that enables high-resolution video to be shared across two mobile devices when they are close to each other. This concept has its inspiration in machine-to-machine connections in the Internet of Things （loT）. We ensure that the two parts of the video are the same size over both screens and are synchronous. Further, a user can play, pause, or stop the video by moving one device a certain distance from the other. We decide on appropriate distances through experimentation. We implemented WeWatch on Android operating system and then optimize Watch so battery consumption is reduced. The user experience provided by WeWatch was evaluated by students through a questionnaire, and the reviews indicated that WeWatch does improve the viewing experience.
基金Supported by the National Natural Science Foundation of China(61401496)
文摘This paper described an improved underwater confrontation simulation method of naval amphibious operational training system. The initial position of submarine forces on the enemy is generated automatically, and the attacking distance model of torpedoes is established based on the kinematics theory, which is more flexible and reasonable to judge the launch condition compared to traditional method. The two kinds of confrontation behavior models on the enemy submarine are created to depict its tactical action from the defensive to the offensive as well as the contrary, ensuring that operational style is simulated more comprehensively and properly. The existing motion trajectory estimation and collision detection algorithms on operational platforms are also improved to reduce the iteration error and further enhance the detection accuracy of target hit.
基金Project supported by the National Natural Science Foundation of China(Nos.U1909209 and 61503104)the Open Foundation of Hypervelocity Impact Research Center of China Aerodynamics Research and Development Centerthe Research Start-up Funding,China(No.2019RC020)。
文摘Hypervelocity impact(HVI)vibration source identification and localization have found wide applications in many fields,such as manned spacecraft protection and machine tool collision damage detection and localization.In this paper,we study the synchrosqueezed transform(SST)algorithm and the texture color distribution(TCD)based HVI source identification and localization using impact images.The extracted SST and TCD image features are fused for HVI image representation.To achieve more accurate detection and localization,the optimal selective stitching features OSSST+TCD are obtained by correlating and evaluating the similarity between the sample label and each dimension of the features.Popular conventional classification and regression models are merged by voting and stacking to achieve the final detection and localization.To demonstrate the effectiveness of the proposed algorithm,the HVI data recorded from three kinds of high-speed bullet striking on an aluminum alloy plate is used for experimentation.The experimental results show that the proposed HVI identification and localization algorithm is more accurate than other algorithms.Finally,based on sensor distribution,an accurate four-circle centroid localization algorithm is developed for HVI source coordinate localization.
