Classification of multi-dimension time series(MTS) plays an important role in knowledge discovery of time series. Many methods for MTS classification have been presented. However, most of these methods did not conside...Classification of multi-dimension time series(MTS) plays an important role in knowledge discovery of time series. Many methods for MTS classification have been presented. However, most of these methods did not consider the kind of MTS whose discriminative subsequence was not restricted to one dimension and dynamic. In order to solve the above problem, a method to extract new features with extended shapelet transformation is proposed in this study. First, key features is extracted to replace k shapelets to calculate distance, which are extracted from candidate shapelets with one class for all dimensions. Second, feature of similarity numbers as a new feature is proposed to enhance the reliability of classification. Third, because of the time-consuming searching and clustering of shapelets, distance matrix is used to reduce the computing complexity. Experiments are carried out on public dataset and the results illustrate the effectiveness of the proposed method. Moreover, anode current signals(ACS) in the aluminum reduction cell are the aforementioned MTS, and the proposed method is successfully applied to the classification of ACS.展开更多
The electrical characteristics of GaN schottky diode with and without the interracial oxides are compared in this paper. The influence of interracial oxides on the electrical characteristics of the schottky diodes has...The electrical characteristics of GaN schottky diode with and without the interracial oxides are compared in this paper. The influence of interracial oxides on the electrical characteristics of the schottky diodes has been confirmed by the I-V, C-V measures. We find the barrier height have a reduction of 0.05 eV- 0.1 eV. There is an interracial insulating oxide with the thickness of 0. 05 nm- 0. 1 nm after conventional cleaning. Either the forward or the backward currents increase. The backward punch through voltages are reduced to 50% and the capacitances have increased by 100%.展开更多
Research on neuro signals is challenging and significative in modern natural science. By clinical experiment, signals from three main nerves (median nerve, radial nerve and ulnar nerve) are successfully detected and r...Research on neuro signals is challenging and significative in modern natural science. By clinical experiment, signals from three main nerves (median nerve, radial nerve and ulnar nerve) are successfully detected and recorded without any infection. Further analysis on their features under different movements, their mechanics and correlations in dominating actions are also performed. The original discovery and first-hand materials make it possible for developing practical neuro-prosthesis.展开更多
Avalanche photodiodes(APDs) are promising light sensors with high quantum efficiency and low noise. It has been extensively used in radiation detection,laser radar and other weak signal detection fields. Unlike other ...Avalanche photodiodes(APDs) are promising light sensors with high quantum efficiency and low noise. It has been extensively used in radiation detection,laser radar and other weak signal detection fields. Unlike other photodiodes,APD is a very sensitive light detector with very high internal gain. The basic theory shows that the gain of APD is related to the temperature. The internal gain fluctuates with the variation of temperature. Investigated was the influence of the variation of the gain induced by the fluctuation of temperature on the output from APD for a very weak laser pulse input in laser radar. An active reverse-biased voltage compensation method is used to stabilize the gain of APD. An APD model is setup to simulate the detection of light pulse signal. The avalanche process,various noises and temperature's effect are all included in the model. Our results show that for the detection of weak light signal such as in laser radar,even a very small fluctuation of temperature could cause a great effect on APD's gain. The results show that the signal-to-noise ratio of the APD's output could be improved effectively with the active gain-control system.展开更多
The general analysis of the forward AC behavior of a semiconductor diode under series mode is pre- sented for the first time.A new method without any particular assumption to characterize a diode was developed. This m...The general analysis of the forward AC behavior of a semiconductor diode under series mode is pre- sented for the first time.A new method without any particular assumption to characterize a diode was developed. This method can accurately measure the dependence of series resistance, junction capacitance, junction vol- tage, ideality factor, and interfacial layer impedance on forward biases. The measurements confirm that the ne- gative capacitance (NC) of Schottky diode is an effect of the junction, and the interfacial layer can be consi- dered as a layer structure with nonlinear resistance and capacitance.展开更多
Performance characteristics data of solar photovoltaic （PV） cell/module are conventionally obtained under standard testing conditions. In the present work, the performance of PV modules under extreme temperatures an...Performance characteristics data of solar photovoltaic （PV） cell/module are conventionally obtained under standard testing conditions. In the present work, the performance of PV modules under extreme temperatures and insolations experienced in State of Qatar was utilized to aid presenting a simplified characterization approach for the special case of arid environmental conditions. The chosen model was the well-known single diode model with both series and parallel resistors for greater accuracy. The modeling technique was validated by comparing the numerically calculated electrical characteristics with experimentally obtained data using two approaches： a single indoor fixed monocrystalline PV module inside a solar simulation chamber which physically simulated different weather scenarios by changing irradiation intensities and temperature, and a set of outdoor fixed polycrystalline PV modules. The result of the indoor experiment was presented in form of performance curves, and the outdoor experiment results in a monthly accumulated power production chart format. Both illustration types showed acceptable tolerance.展开更多
To study the alternating current （AC） impedance properties of Ag/AgC1 electrocardiograph （ECG） electrodes, the electrode pair was gel-to-gel connected, and then the electrical potential was recorded after a safe s...To study the alternating current （AC） impedance properties of Ag/AgC1 electrocardiograph （ECG） electrodes, the electrode pair was gel-to-gel connected, and then the electrical potential was recorded after a safe stimulating current passes through the electrode pair, so the AC impedance data of ECG electrodes were obtained. Varying the frequency and value of stimulating current, the detailed comparison and analysis of AC impedance properties of the electrodes were performed, and the stability was further characterized by using the continuous measurement within 24 h. The experimental results show that the AC impedance values of electrodes decreased, and then slightly increased with the increase of frequency of stimulating current. The minimum AC impedance value was obtained when the frequency was changed to 10 kHz. When the stimulating current increased, the AC impedance values of electrodes showed a slight decrease, but did not change significantly. Besides, the continuous measurement results show that the impedance value presented a significant increase in the initial 30 min, and then was stabilized in the following measuring process.展开更多
The dark current of In_(0.47) Ga_(0.53) As/InP heterojunction photodiodes (HPDs) was analysed. We found that there exists a new dark current component──deep level-assisted tunnelling current.DLTS was used to measure...The dark current of In_(0.47) Ga_(0.53) As/InP heterojunction photodiodes (HPDs) was analysed. We found that there exists a new dark current component──deep level-assisted tunnelling current.DLTS was used to measure the In_(0.47)Ga_(0.53)As/InP HPDs. An electronic trap which has a thermal activation energy of O.44 eV, level concentration of 3.10×10￣(13)cm￣(-3) and electronic capture cross section of 1.72×10￣(12)cm￣2 has been found.It's existence results in the new tunnelling current.展开更多
基金Projects(61773405,61725306,61533020)supported by the National Natural Science Foundation of ChinaProject(2018zzts583)supported by the Fundamental Research Funds for the Central Universities,China
文摘Classification of multi-dimension time series(MTS) plays an important role in knowledge discovery of time series. Many methods for MTS classification have been presented. However, most of these methods did not consider the kind of MTS whose discriminative subsequence was not restricted to one dimension and dynamic. In order to solve the above problem, a method to extract new features with extended shapelet transformation is proposed in this study. First, key features is extracted to replace k shapelets to calculate distance, which are extracted from candidate shapelets with one class for all dimensions. Second, feature of similarity numbers as a new feature is proposed to enhance the reliability of classification. Third, because of the time-consuming searching and clustering of shapelets, distance matrix is used to reduce the computing complexity. Experiments are carried out on public dataset and the results illustrate the effectiveness of the proposed method. Moreover, anode current signals(ACS) in the aluminum reduction cell are the aforementioned MTS, and the proposed method is successfully applied to the classification of ACS.
基金The National Natural Science Foundation of China(G0501030160576007)
文摘The electrical characteristics of GaN schottky diode with and without the interracial oxides are compared in this paper. The influence of interracial oxides on the electrical characteristics of the schottky diodes has been confirmed by the I-V, C-V measures. We find the barrier height have a reduction of 0.05 eV- 0.1 eV. There is an interracial insulating oxide with the thickness of 0. 05 nm- 0. 1 nm after conventional cleaning. Either the forward or the backward currents increase. The backward punch through voltages are reduced to 50% and the capacitances have increased by 100%.
文摘Research on neuro signals is challenging and significative in modern natural science. By clinical experiment, signals from three main nerves (median nerve, radial nerve and ulnar nerve) are successfully detected and recorded without any infection. Further analysis on their features under different movements, their mechanics and correlations in dominating actions are also performed. The original discovery and first-hand materials make it possible for developing practical neuro-prosthesis.
基金Young Scientist Research Fund of Heilongjiang University(QL200508)
文摘Avalanche photodiodes(APDs) are promising light sensors with high quantum efficiency and low noise. It has been extensively used in radiation detection,laser radar and other weak signal detection fields. Unlike other photodiodes,APD is a very sensitive light detector with very high internal gain. The basic theory shows that the gain of APD is related to the temperature. The internal gain fluctuates with the variation of temperature. Investigated was the influence of the variation of the gain induced by the fluctuation of temperature on the output from APD for a very weak laser pulse input in laser radar. An active reverse-biased voltage compensation method is used to stabilize the gain of APD. An APD model is setup to simulate the detection of light pulse signal. The avalanche process,various noises and temperature's effect are all included in the model. Our results show that for the detection of weak light signal such as in laser radar,even a very small fluctuation of temperature could cause a great effect on APD's gain. The results show that the signal-to-noise ratio of the APD's output could be improved effectively with the active gain-control system.
文摘The general analysis of the forward AC behavior of a semiconductor diode under series mode is pre- sented for the first time.A new method without any particular assumption to characterize a diode was developed. This method can accurately measure the dependence of series resistance, junction capacitance, junction vol- tage, ideality factor, and interfacial layer impedance on forward biases. The measurements confirm that the ne- gative capacitance (NC) of Schottky diode is an effect of the junction, and the interfacial layer can be consi- dered as a layer structure with nonlinear resistance and capacitance.
文摘Performance characteristics data of solar photovoltaic （PV） cell/module are conventionally obtained under standard testing conditions. In the present work, the performance of PV modules under extreme temperatures and insolations experienced in State of Qatar was utilized to aid presenting a simplified characterization approach for the special case of arid environmental conditions. The chosen model was the well-known single diode model with both series and parallel resistors for greater accuracy. The modeling technique was validated by comparing the numerically calculated electrical characteristics with experimentally obtained data using two approaches： a single indoor fixed monocrystalline PV module inside a solar simulation chamber which physically simulated different weather scenarios by changing irradiation intensities and temperature, and a set of outdoor fixed polycrystalline PV modules. The result of the indoor experiment was presented in form of performance curves, and the outdoor experiment results in a monthly accumulated power production chart format. Both illustration types showed acceptable tolerance.
基金Project(111gpy06) supported by Fundamental Research Funds for the Central Universities,ChinaProject(101055807) supported by the Innovative Experiment Plan for College Students of Sun Yat-sen University,ChinaProject(KF201115) supported by the Opening Fund of Laboratory Sun Yat-sen University,China
文摘To study the alternating current （AC） impedance properties of Ag/AgC1 electrocardiograph （ECG） electrodes, the electrode pair was gel-to-gel connected, and then the electrical potential was recorded after a safe stimulating current passes through the electrode pair, so the AC impedance data of ECG electrodes were obtained. Varying the frequency and value of stimulating current, the detailed comparison and analysis of AC impedance properties of the electrodes were performed, and the stability was further characterized by using the continuous measurement within 24 h. The experimental results show that the AC impedance values of electrodes decreased, and then slightly increased with the increase of frequency of stimulating current. The minimum AC impedance value was obtained when the frequency was changed to 10 kHz. When the stimulating current increased, the AC impedance values of electrodes showed a slight decrease, but did not change significantly. Besides, the continuous measurement results show that the impedance value presented a significant increase in the initial 30 min, and then was stabilized in the following measuring process.
文摘The dark current of In_(0.47) Ga_(0.53) As/InP heterojunction photodiodes (HPDs) was analysed. We found that there exists a new dark current component──deep level-assisted tunnelling current.DLTS was used to measure the In_(0.47)Ga_(0.53)As/InP HPDs. An electronic trap which has a thermal activation energy of O.44 eV, level concentration of 3.10×10￣(13)cm￣(-3) and electronic capture cross section of 1.72×10￣(12)cm￣2 has been found.It's existence results in the new tunnelling current.
