In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indi...In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indicate that the evolutions of wave velocities became progressively anisotropic under uniaxial loading due to the direction-dependent development of micro-damage.A wave velocity model considering the inner anisotropic crack evolution is proposed to accurately describe the variations of wave velocities during uniaxial compression testing.Based on which,the effective elastic parameters are inferred by a transverse isotropic constitutive model,and the evolutions of the crack density are inversed using a self-consistent damage model.It is found that the propagation of axial cracks dominates the failure process of brittle rock under uniaxial loading and oblique shear cracks develop with the appearance of macrocrack.展开更多
Ship motions induced by waves have a significant impact on the efficiency and safety of offshore operations.Real-time prediction of ship motions in the next few seconds plays a crucial role in performing sensitive act...Ship motions induced by waves have a significant impact on the efficiency and safety of offshore operations.Real-time prediction of ship motions in the next few seconds plays a crucial role in performing sensitive activities.However,the obvious memory effect of ship motion time series brings certain difficulty to rapid and accurate prediction.Therefore,a real-time framework based on the Long-Short Term Memory(LSTM)neural network model is proposed to predict ship motions in regular and irregular head waves.A 15000 TEU container ship model is employed to illustrate the proposed framework.The numerical implementation and the real-time ship motion prediction in irregular head waves corresponding to the different time scales are carried out based on the container ship model.The related experimental data were employed to verify the numerical simulation results.The results show that the proposed method is more robust than the classical extreme short-term prediction method based on potential flow theory in the prediction of nonlinear ship motions.展开更多
BACKGROUND Real-time shear wave elastography(SWE)is a non-invasive imaging technique used to measure tissue stiffness by generating and tracking shear waves in real time.This advanced ultrasound-based method provides ...BACKGROUND Real-time shear wave elastography(SWE)is a non-invasive imaging technique used to measure tissue stiffness by generating and tracking shear waves in real time.This advanced ultrasound-based method provides quantitative information regarding tissue elasticity,offering valuable insights into the mechanical properties of biological tissues.However,the application of real-time SWE in the musculoskeletal system and sports medicine has not been extensively studied.AIM To explore the practical value of real-time SWE for assessing Achilles tendon hardness in older adults.METHODS A total of 60 participants were enrolled in the present study,and differences in the elastic moduli of the bilateral Achilles tendons were compared among the following categories:(1)Age:55-60,60-65,and 65-70-years-old;(2)Sex:Male and female;(3)Laterality:Left and right sides;(4)Tendon state:Relaxed and tense state;and(5)Tendon segment:Proximal,middle,and distal.RESULTS There were no significant differences in the elastic moduli of the bilateral Achilles tendons when comparing by age or sex(P>0.05).There were,however,significant differences when comparing by tendon side,state,or segment(P<0.05).CONCLUSION Real-time SWE plays a significant role compared to other examination methods in the evaluation of Achilles tendon hardness in older adults.展开更多
Cardiovascular diseases(CVDs)continue to present a leading cause ofmortalityworldwide,emphasizing the importance of early and accurate prediction.Electrocardiogram(ECG)signals,central to cardiac monitoring,have increa...Cardiovascular diseases(CVDs)continue to present a leading cause ofmortalityworldwide,emphasizing the importance of early and accurate prediction.Electrocardiogram(ECG)signals,central to cardiac monitoring,have increasingly been integratedwithDeep Learning(DL)for real-time prediction of CVDs.However,DL models are prone to performance degradation due to concept drift and to catastrophic forgetting.To address this issue,we propose a realtime CVDs prediction approach,referred to as ADWIN-GFR that combines Convolutional Neural Network(CNN)layers,for spatial feature extraction,with Gated Recurrent Units(GRU),for temporal modeling,alongside adaptive drift detection and mitigation mechanisms.The proposed approach integratesAdaptiveWindowing(ADWIN)for realtime concept drift detection,a fine-tuning strategy based on Generative Features Replay(GFR)to preserve previously acquired knowledge,and a dynamic replay buffer ensuring variance,diversity,and data distribution coverage.Extensive experiments conducted on the MIT-BIH arrhythmia dataset demonstrate that ADWIN-GFR outperforms standard fine-tuning techniques,achieving an average post-drift accuracy of 95.4%,amacro F1-score of 93.9%,and a remarkably low forgetting score of 0.9%.It also exhibits an average drift detection delay of 12 steps and achieves an adaptation gain of 17.2%.These findings underscore the potential of ADWIN-GFR for deployment in real-world cardiac monitoring systems,including wearable ECG devices and hospital-based patient monitoring platforms.展开更多
Objective:To explore the value of real-time elastic shear wave in evaluating muscle elasticity in patients with renal failure.Methods:50 patients with chronic renal failure from January 2019 to December 2022 were rand...Objective:To explore the value of real-time elastic shear wave in evaluating muscle elasticity in patients with renal failure.Methods:50 patients with chronic renal failure from January 2019 to December 2022 were randomly selected as the experimental group,and 50 healthy patients aged 21-61 during the same period were selected as the control group,and the basic information of the patients,including age,gender,body mass index,etc.,were collected.Besides,the Young's modulus of the two groups of patients were observed and analyzed.Results:The Young's modulus values of left and right gastrocnemius muscles in the experimental group were significantly lower than those in the control group(P<0.05),and there was no statistical difference between the left and right sides of the experimental group and the control group(P>0.05).Conclusion:Real-time shear wave elastography provides a non-invasive,real-time and effective tool for the assessment of muscle elasticity in patients with renal failure.Through further research and optimization,real-time shear wave elastography will play a greater role in the prevention and treatment of patients with renal failure,improving the quality of life and prognosis of patients.展开更多
Purpose: Respiratory-gated radiation therapy (RT) using the real-time tumor-tracking radiotherapy (RTRT) system is an effective technique for managing tumor motion. High dosimetric and geometric accuracy is needed;how...Purpose: Respiratory-gated radiation therapy (RT) using the real-time tumor-tracking radiotherapy (RTRT) system is an effective technique for managing tumor motion. High dosimetric and geometric accuracy is needed;however, quality assurance (QA) for respiratory-gated RT using the RTRT system has not been reported. The purpose of this study was to perform QA for respiratorygated RT using the RTRT system. Materials and Methods: The RTRT system detected the position of the fiducial marker and radiation delivery gated to the motion of the marker was performed. The dynamic anthropomorphic thorax phantom was positioned at the isocenter using the fiducial marker in the phantom. The phantom was irradiated only when the fiducial marker was within a three-dimensional gating window of ±2 mm from the planned position. First, the absolute doses were measured using anionization chamber inserted in the phantom under the stationary, gating and non-gating state for sinusoidal (nadir-to-peak amplitude [A]: 20 - 40 mm, breathing period [T]: 2 - 4 s) and the basic respiratory patterns. Second, the dose profiles were measured using Gafchromic films in the phantom under the same conditions. Differences between dose profiles were calculated to evaluate the dosimetric and geometric accuracy. Finally, differences between the actual and measured position of the fiducial marker were calculated to evaluate the tracking accuracy for sinusoidal and basic respiratory patterns. Results: For the sinusoidal patterns, the relative doses were 0.93 for non-gating and 0.99 for gating (A = 20 mm, T = 2 s), 0.94 for non-gating and 1.00 for gating (A = 20 mm, T = 4 s), 0.55 for non-gating and 1.00 for gating (A = 40 mm, T = 4 s), respectively. For the basic respiratory pattern, the relative doses were 1.00 for non-gating and 1.00 for gating, respectively. Compared to the stationary conditions, the differences in lateral distance between the 90% dose of dose profiles were 6.23 mm for non-gating and 0.36 mm for gating (A = 20 mm, T = 2 s), 8.79 mm for non-gating and 1.73 mm for gating (A = 20 mm, T = 4 s), 18.37 mm for non-gating and 0.67 mm for gating (A = 40 mm, T = 4 s), respectively. For the basic respiratory pattern, those were 5.23 mm for non-gating and 0.35 mm for gating. The root mean square (RMS) values of the tracking error were 0.18 mm (A = 20 mm, T = 2 s), 0.14 mm (A = 20 mm, T = 4 s), and 0.21 mm (A = 40 mm, T = 4 s) for sinusoidal and 0.79 mm for the basic respiratory pattern, respectively. Conclusion: We conducted QA for respiratory-gated RT using the RTRT system. The respiratory-gated RT using the RTRT system reduced the blurring effects on dose distribution with high dosimetric and geometric accuracy.展开更多
A gated viewing laser radar has an excellent performance in underwater low light level imaging, and it also provides a viable solution to inhibit backscattering. In this paper, a gated viewing imaging system according...A gated viewing laser radar has an excellent performance in underwater low light level imaging, and it also provides a viable solution to inhibit backscattering. In this paper, a gated viewing imaging system according to the demand for real-time imaging is presented, and then the simulation is used to analyze the performance of the real-time gated viewing system. The range accuracy performance is limited by the slice number, the width of gate, the delay time step, the initial delay time, as well as the system noise and atmospheric turbulence. The simulation results indicate that the highest range accuracy can be achieved when the system works with the optimal parameters. Finally, how to choose the optimal parameters has been researched.展开更多
In this study, the physics-based device simulation tool Silvaco ATLAS is used to characterize the electrical properties of an AlGaN/GaN high electron mobility transistor （HEMT） with a U-type gate foot. The U-gate Al...In this study, the physics-based device simulation tool Silvaco ATLAS is used to characterize the electrical properties of an AlGaN/GaN high electron mobility transistor （HEMT） with a U-type gate foot. The U-gate AlGaN/GaN HEMT mainly features a gradually changed sidewall angle, which effectively mitigates the electric field in the channel, thus obtaining enhanced off-state breakdown characteristics. At the same time, only a small additional gate capacitance and decreased gate resistance ensure excellent RF characteristics for the U-gate device. U-gate AlGaN/GaN HEMTs are feasible through adjusting the etching conditions of an inductively coupled plasma system, without introducing any extra process steps. The simulation results are confirmed by experimental measurements. These features indicate that U-gate A1GaN/GaN HEMTs might be promising candidates for use in millimeter-wave power applications.展开更多
Simulation and rendering of large-scale natural environments, especially the ocean, has always been one of the hot issues in computer graphics, which can provide realism for various applications such as computer game,...Simulation and rendering of large-scale natural environments, especially the ocean, has always been one of the hot issues in computer graphics, which can provide realism for various applications such as computer game, movie and military usage. Simulation of ocean environment is often lack of realism for real-time application due to its complexity of dynamic waves. In this paper, a method based on FFT Wave model is proposed to solve this problem, which can also simulate the ocean optic property with atmosphere scattering. Furthermore, our method has a lot of advantages including global ocean dataset support, real-time, dynamic reflection of ocean, the foam on the wave, smooth transition from deep ocean to seacoast, etc. The experimental results demonstrate the realism and effectiveness of our approach.展开更多
A novel reconfigurable hardware system which uses both muhi-DSP and FPGA to attain high performance and real-time image processing are presented. The system structure and working principle of mainly processing multi-B...A novel reconfigurable hardware system which uses both muhi-DSP and FPGA to attain high performance and real-time image processing are presented. The system structure and working principle of mainly processing multi-BSP board, extended multi-DSP board are analysed. The outstanding advantage is that the communication among different board components of this system is supported by high speed link ports ＆ serial ports for increasing the system performance and computational power. Then the implementation of embedded real-time operating systems （RTOS） by us is discussed in detail. In this system, we adopt two kinds of parallel structures controlled by RTOS for parallel processing of algorithms. The experimental results show that exploitive period of the system is short, and maintenance convenient. Thus it is suitable for real-time image processing and can get satisfactory effect of image recognition.展开更多
Abstract： Real-time digital service and mul- timedia service upstream transmission in Dig- ital Signal Processing （DSP）-based Orthogo- nal Frequency Division Multiplexing-Passive Optical Network （OFDM-PON） is exp...Abstract： Real-time digital service and mul- timedia service upstream transmission in Dig- ital Signal Processing （DSP）-based Orthogo- nal Frequency Division Multiplexing-Passive Optical Network （OFDM-PON） is experimen- tally demonstrated with Centralised Light Sou- rce （CLS） configuration in this paper. After transmitted over 25 km Standard Single Mode Fibre （SSMF） with -16.5 dBm optical power at receiver, the Bit Error Rate （BER） is 9.5 ×10^-11. The implementations of digital domain up-conversion and down-conversion based on Field Programmable Gate Array （FPGA） are int- roduced, which can reduce the cost of In-ph- ase and Quadrature （IQ） radio frequency mix- ers utilised at transmitter and receiver. A car- rier synchronization algorithm is implemented for compensating carrier offset. A channel eq- ualization algorithm is adopted for compen- sating the damage of channel. A new structure of Frequency Synchronization Unit （FSU） des- igned in FPGA is also proposed to cope with the frequency shifting at receiver.展开更多
The instability of terahertz（THz）plasma waves in two-dimensional（2D）quantum electron gas in a nanometer field effect transistor（FET）with asymmetrical boundary conditions has been investigated.We analyze THz plas...The instability of terahertz（THz）plasma waves in two-dimensional（2D）quantum electron gas in a nanometer field effect transistor（FET）with asymmetrical boundary conditions has been investigated.We analyze THz plasma waves of two parts of the 2D quantum electron gas：gated and ungated regions.The results show that the radiation frequency and the increment（radiation power）in 2D ungated quantum electron gas are much higher than that in 2D gated quantum electron gas.The quantum effects always enhance the radiation power and enlarge the region of instability in both cases.This allows us to conclude that 2D quantum electron gas in the transistor channel is important for the emission and detection process and both gated and ungated parts take part in that process.展开更多
In this paper, we proposed a new concept: depth of drowsiness, which can more precisely describe the drowsiness than existing binary description. A set of effective markers for drowsiness: normalized band norm was suc...In this paper, we proposed a new concept: depth of drowsiness, which can more precisely describe the drowsiness than existing binary description. A set of effective markers for drowsiness: normalized band norm was successfully developed. These markers are invariant from voltage amplitude of brain waves, eliminating the need for calibrating the voltage output of the brain-computer interface devices. A new polling algorithm was designed and implemented for computing the depth of drowsiness. The time cost of data acquisition and processing for each estimate is about one second, which is well suited for real-time applications. Test results with a portable brain-computer interface device show that the depth of drowsiness computed by the method in this paper is generally invariant from ages of test subjects and sensor channels (P3 and C4). The comparison between experiment and computing results indicate that the new method is noticeably better than one of the recent methods in terms of accuracy for predicting the drowsiness.展开更多
A wave forecasting system using FUNWAVE-TVD which is based on the fully nonlinear Boussinesq equations by Chen(2006)was developed to provide an accurate wave prediction in the Port of Busan,South Korea.This system is ...A wave forecasting system using FUNWAVE-TVD which is based on the fully nonlinear Boussinesq equations by Chen(2006)was developed to provide an accurate wave prediction in the Port of Busan,South Korea.This system is linked to the Korea Operational Oceanographic System(KOOS)developed by Park et al.(2015).The computational domain covers a region of 9.6 km×7.0 km with a grid size of 2 m in both directions,which is sufficient to resolve short waves and dominant sea states.The total number of grid points exceeds 16 millions,making the model computational expensive.To provide real-time forecasting,an interpolation method,which is based on pre-calculated results of FUNWAVE-TVD and SWAN forecasting results at the FUNWAVE-TVD offshore boundary,was used.A total of 45 cases were pre-calculated,which took 71 days on 924 computational cores of a Linux cluster system.Wind wave generation and propagation from the deep water were computed using the SWAN in KOOS.SWAN results provided a boundary condition for the FUNWAVE-TVD forecasting system.To verify the model,wave observations were conducted at three locations inside the port in a time period of more than 7 months.A model/model comparison between FUNWAVE-TVD and SWAN was also carried out.It is found that,FUNWAVE-TVD improves the forecasting results significantly compared to SWAN which underestimates wave heights in sheltered areas due to incorrect physical mechanism of wave diffraction,as well as large wave heights caused by wave reflections inside the port.展开更多
A novel matching method for simultaneous multi-target recognition is proposed by jointly considering target's prior scattering knowledge and the polarization parameters of radar echoes. The matching coefficients a...A novel matching method for simultaneous multi-target recognition is proposed by jointly considering target's prior scattering knowledge and the polarization parameters of radar echoes. The matching coefficients are calculated for the judgment. MATLAB simulations show that several targets can be accurately recognized simultaneously, and a high recognition probability can be achieved in Monte Carlo simulations. The total execution time can be remarkably reduced in the Field Programmable Gate Array (FPGA) implementation of the matching procedure.展开更多
A binary tree representation is designed in this paper for optimization of wave digital filter（WDF）implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree repres...A binary tree representation is designed in this paper for optimization of wave digital filter（WDF）implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree representation at first.This WDF binary tree can then be transformed to several topologies with the same implication,since the WDF adaptors have a symmetrical behavior on their ports.Because the WDF implementation is related to field programmable gate array（FPGA）resource usage and the cycle time of emulation,choosing aproper binary tree topology for WDF implementation can help balance the complexity and performance quality of an emulation system.Both WDF-FPGA emulation and HSpice simulation on the same circuit are tested.There is no significant difference between these two simulations.However,in terms of time consumption,the WDF-FPGA emulation has an advantage over the other.Our experiment also demonstrates that the optimized WDF-FPGA emulation has an acceptable accuracy and feasibility.展开更多
We propose a novel optical method for glucose measurement based on difuse photon-pair density wave(DPPDW)in a multiple scattering medium(MSM)where the light scattering of photon-pair is induced by refractive index mis...We propose a novel optical method for glucose measurement based on difuse photon-pair density wave(DPPDW)in a multiple scattering medium(MSM)where the light scattering of photon-pair is induced by refractive index mismatch between scatters and phantom solution.Experi-mentally,the DPPDW propagates in MSM via a two frequency laser(TFL)beam wherein highly correlated pairs of linear polarized photons are generated.The reduced scattering coefficientμ2s and absorption coefficientμ2a of DPPDW are measured simultaneously in terms of the amplitude and phase measurements of the detected heterodyne signal under arrangement at different dis-tances between the source and detection fibers in MSM.The results show that the sensitivity of glucose detection via glucose-induced change of reduced scattering coefficient(δμ′2)is 0.049%mM^(-1)in a 1%intralipid solution.In addition,the linear range ofδμ′2s vs glucose concentration implies that this DPPDW method can be used to monitor glucose concentration continuously and noninvasively subcutaneously.展开更多
GHz single-photon detector(SPD)is a crucial part in the practical high speed quantum key distribution(QKD)system.However,any imperfections in a practical QKD system may be exploited by an eavesdropper(Eve)to collect i...GHz single-photon detector(SPD)is a crucial part in the practical high speed quantum key distribution(QKD)system.However,any imperfections in a practical QKD system may be exploited by an eavesdropper(Eve)to collect information about the key without being discovered.The sine wave gating SPD(SG-SPD)based on InGaAs/InP avalanche photodiode,one kind of practical high speed SPD,may also contain loopholes.In this paper,we study the principle and characteristic of the SG-SPD and find out the filtering loophole of the SG-SPD for the first time.What is more,the proof-of-principle experiment shows that Eve could blind and control Bob's SG-SPD by exploiting this loophole.We believe that giving enough attention to this loophole can improve the practical security of the existing QKD system.GHz single-photon detector(SPD)is a crucial part in the practical high speed quantum key distribution(QKD)system.However,any imperfections in a practical QKD system may be exploited by an eavesdropper(Eve)to collect information about the key without being discovered.The sine wave gating SPD(SG-SPD)based on InGaAs/InP avalanche photodiode,one kind of practical high speed SPD,may also contain loopholes.In this paper,we study the principle and characteristic of the SG-SPD and find out the filtering loophole of the SG-SPD for the first time.What is more,the proof-of-principle experiment shows that Eve could blind and control Bob's SG-SPD by exploiting this loophole.We believe that giving enough attention to this loophole can improve the practical security of the existing QKD system.展开更多
All-optical XNOR and AND logic gates using four-wave mixing （FWM） and cross-gain modulation （XGM） in a single semiconductor optical amplifier （SOA） with improved dynamics are simultaneously realized. By numerica...All-optical XNOR and AND logic gates using four-wave mixing （FWM） and cross-gain modulation （XGM） in a single semiconductor optical amplifier （SOA） with improved dynamics are simultaneously realized. By numerical simulation, the effects of the input optical wave powers and injection current on the critical factors of the logic gate performances, such as the ON-OFF contrast ratio, the power-output level of the logic ＇1＇, and the difference between power outputs of the logic ＇1＇, are investigated in detail. In addition, the effect of the counter-propagating CW pump on the gain recovery is analysed.展开更多
基金Projects(41502283,41772309)supported by the National Natural Science Foundation of ChinaProject(2017YFC1501302)supported by the National Key Research and Development Program of ChinaProject(2017ACA102)supported by the Major Program of Technological Innovation of Hubei Province,China。
文摘In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indicate that the evolutions of wave velocities became progressively anisotropic under uniaxial loading due to the direction-dependent development of micro-damage.A wave velocity model considering the inner anisotropic crack evolution is proposed to accurately describe the variations of wave velocities during uniaxial compression testing.Based on which,the effective elastic parameters are inferred by a transverse isotropic constitutive model,and the evolutions of the crack density are inversed using a self-consistent damage model.It is found that the propagation of axial cracks dominates the failure process of brittle rock under uniaxial loading and oblique shear cracks develop with the appearance of macrocrack.
文摘Ship motions induced by waves have a significant impact on the efficiency and safety of offshore operations.Real-time prediction of ship motions in the next few seconds plays a crucial role in performing sensitive activities.However,the obvious memory effect of ship motion time series brings certain difficulty to rapid and accurate prediction.Therefore,a real-time framework based on the Long-Short Term Memory(LSTM)neural network model is proposed to predict ship motions in regular and irregular head waves.A 15000 TEU container ship model is employed to illustrate the proposed framework.The numerical implementation and the real-time ship motion prediction in irregular head waves corresponding to the different time scales are carried out based on the container ship model.The related experimental data were employed to verify the numerical simulation results.The results show that the proposed method is more robust than the classical extreme short-term prediction method based on potential flow theory in the prediction of nonlinear ship motions.
基金Supported by Sichuan Orthopaedic Hospital Research Project,No.2019MS02.
文摘BACKGROUND Real-time shear wave elastography(SWE)is a non-invasive imaging technique used to measure tissue stiffness by generating and tracking shear waves in real time.This advanced ultrasound-based method provides quantitative information regarding tissue elasticity,offering valuable insights into the mechanical properties of biological tissues.However,the application of real-time SWE in the musculoskeletal system and sports medicine has not been extensively studied.AIM To explore the practical value of real-time SWE for assessing Achilles tendon hardness in older adults.METHODS A total of 60 participants were enrolled in the present study,and differences in the elastic moduli of the bilateral Achilles tendons were compared among the following categories:(1)Age:55-60,60-65,and 65-70-years-old;(2)Sex:Male and female;(3)Laterality:Left and right sides;(4)Tendon state:Relaxed and tense state;and(5)Tendon segment:Proximal,middle,and distal.RESULTS There were no significant differences in the elastic moduli of the bilateral Achilles tendons when comparing by age or sex(P>0.05).There were,however,significant differences when comparing by tendon side,state,or segment(P<0.05).CONCLUSION Real-time SWE plays a significant role compared to other examination methods in the evaluation of Achilles tendon hardness in older adults.
基金supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2025R196)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia.
文摘Cardiovascular diseases(CVDs)continue to present a leading cause ofmortalityworldwide,emphasizing the importance of early and accurate prediction.Electrocardiogram(ECG)signals,central to cardiac monitoring,have increasingly been integratedwithDeep Learning(DL)for real-time prediction of CVDs.However,DL models are prone to performance degradation due to concept drift and to catastrophic forgetting.To address this issue,we propose a realtime CVDs prediction approach,referred to as ADWIN-GFR that combines Convolutional Neural Network(CNN)layers,for spatial feature extraction,with Gated Recurrent Units(GRU),for temporal modeling,alongside adaptive drift detection and mitigation mechanisms.The proposed approach integratesAdaptiveWindowing(ADWIN)for realtime concept drift detection,a fine-tuning strategy based on Generative Features Replay(GFR)to preserve previously acquired knowledge,and a dynamic replay buffer ensuring variance,diversity,and data distribution coverage.Extensive experiments conducted on the MIT-BIH arrhythmia dataset demonstrate that ADWIN-GFR outperforms standard fine-tuning techniques,achieving an average post-drift accuracy of 95.4%,amacro F1-score of 93.9%,and a remarkably low forgetting score of 0.9%.It also exhibits an average drift detection delay of 12 steps and achieves an adaptation gain of 17.2%.These findings underscore the potential of ADWIN-GFR for deployment in real-world cardiac monitoring systems,including wearable ECG devices and hospital-based patient monitoring platforms.
文摘Objective:To explore the value of real-time elastic shear wave in evaluating muscle elasticity in patients with renal failure.Methods:50 patients with chronic renal failure from January 2019 to December 2022 were randomly selected as the experimental group,and 50 healthy patients aged 21-61 during the same period were selected as the control group,and the basic information of the patients,including age,gender,body mass index,etc.,were collected.Besides,the Young's modulus of the two groups of patients were observed and analyzed.Results:The Young's modulus values of left and right gastrocnemius muscles in the experimental group were significantly lower than those in the control group(P<0.05),and there was no statistical difference between the left and right sides of the experimental group and the control group(P>0.05).Conclusion:Real-time shear wave elastography provides a non-invasive,real-time and effective tool for the assessment of muscle elasticity in patients with renal failure.Through further research and optimization,real-time shear wave elastography will play a greater role in the prevention and treatment of patients with renal failure,improving the quality of life and prognosis of patients.
文摘Purpose: Respiratory-gated radiation therapy (RT) using the real-time tumor-tracking radiotherapy (RTRT) system is an effective technique for managing tumor motion. High dosimetric and geometric accuracy is needed;however, quality assurance (QA) for respiratory-gated RT using the RTRT system has not been reported. The purpose of this study was to perform QA for respiratorygated RT using the RTRT system. Materials and Methods: The RTRT system detected the position of the fiducial marker and radiation delivery gated to the motion of the marker was performed. The dynamic anthropomorphic thorax phantom was positioned at the isocenter using the fiducial marker in the phantom. The phantom was irradiated only when the fiducial marker was within a three-dimensional gating window of ±2 mm from the planned position. First, the absolute doses were measured using anionization chamber inserted in the phantom under the stationary, gating and non-gating state for sinusoidal (nadir-to-peak amplitude [A]: 20 - 40 mm, breathing period [T]: 2 - 4 s) and the basic respiratory patterns. Second, the dose profiles were measured using Gafchromic films in the phantom under the same conditions. Differences between dose profiles were calculated to evaluate the dosimetric and geometric accuracy. Finally, differences between the actual and measured position of the fiducial marker were calculated to evaluate the tracking accuracy for sinusoidal and basic respiratory patterns. Results: For the sinusoidal patterns, the relative doses were 0.93 for non-gating and 0.99 for gating (A = 20 mm, T = 2 s), 0.94 for non-gating and 1.00 for gating (A = 20 mm, T = 4 s), 0.55 for non-gating and 1.00 for gating (A = 40 mm, T = 4 s), respectively. For the basic respiratory pattern, the relative doses were 1.00 for non-gating and 1.00 for gating, respectively. Compared to the stationary conditions, the differences in lateral distance between the 90% dose of dose profiles were 6.23 mm for non-gating and 0.36 mm for gating (A = 20 mm, T = 2 s), 8.79 mm for non-gating and 1.73 mm for gating (A = 20 mm, T = 4 s), 18.37 mm for non-gating and 0.67 mm for gating (A = 40 mm, T = 4 s), respectively. For the basic respiratory pattern, those were 5.23 mm for non-gating and 0.35 mm for gating. The root mean square (RMS) values of the tracking error were 0.18 mm (A = 20 mm, T = 2 s), 0.14 mm (A = 20 mm, T = 4 s), and 0.21 mm (A = 40 mm, T = 4 s) for sinusoidal and 0.79 mm for the basic respiratory pattern, respectively. Conclusion: We conducted QA for respiratory-gated RT using the RTRT system. The respiratory-gated RT using the RTRT system reduced the blurring effects on dose distribution with high dosimetric and geometric accuracy.
基金supported by the Pre-research Foundation under Grant No. G020104PJ09DZ0246
文摘A gated viewing laser radar has an excellent performance in underwater low light level imaging, and it also provides a viable solution to inhibit backscattering. In this paper, a gated viewing imaging system according to the demand for real-time imaging is presented, and then the simulation is used to analyze the performance of the real-time gated viewing system. The range accuracy performance is limited by the slice number, the width of gate, the delay time step, the initial delay time, as well as the system noise and atmospheric turbulence. The simulation results indicate that the highest range accuracy can be achieved when the system works with the optimal parameters. Finally, how to choose the optimal parameters has been researched.
基金Project supported by the Major Program of the National Natural Science Foundation of China （Grant No. 60890191） and the National Key Basic Research Program of China （Grant No. 2010CB327503）.
文摘In this study, the physics-based device simulation tool Silvaco ATLAS is used to characterize the electrical properties of an AlGaN/GaN high electron mobility transistor （HEMT） with a U-type gate foot. The U-gate AlGaN/GaN HEMT mainly features a gradually changed sidewall angle, which effectively mitigates the electric field in the channel, thus obtaining enhanced off-state breakdown characteristics. At the same time, only a small additional gate capacitance and decreased gate resistance ensure excellent RF characteristics for the U-gate device. U-gate AlGaN/GaN HEMTs are feasible through adjusting the etching conditions of an inductively coupled plasma system, without introducing any extra process steps. The simulation results are confirmed by experimental measurements. These features indicate that U-gate A1GaN/GaN HEMTs might be promising candidates for use in millimeter-wave power applications.
基金Supported by National Natural Science Foundation of China(Nos.6117020561472010 and 61421062)+2 种基金National Key Technology Support Program(No.2013BAK03B07)National Key Technology R&D Program(2015BAK01B06)Shenzhen Gov Projects(JCYJ20130331144416448)
文摘Simulation and rendering of large-scale natural environments, especially the ocean, has always been one of the hot issues in computer graphics, which can provide realism for various applications such as computer game, movie and military usage. Simulation of ocean environment is often lack of realism for real-time application due to its complexity of dynamic waves. In this paper, a method based on FFT Wave model is proposed to solve this problem, which can also simulate the ocean optic property with atmosphere scattering. Furthermore, our method has a lot of advantages including global ocean dataset support, real-time, dynamic reflection of ocean, the foam on the wave, smooth transition from deep ocean to seacoast, etc. The experimental results demonstrate the realism and effectiveness of our approach.
基金This project was supported by the National Natural Science Foundation of China(60135020) National Key Pre-researchProject of China(413010701 -3) .
文摘A novel reconfigurable hardware system which uses both muhi-DSP and FPGA to attain high performance and real-time image processing are presented. The system structure and working principle of mainly processing multi-BSP board, extended multi-DSP board are analysed. The outstanding advantage is that the communication among different board components of this system is supported by high speed link ports ＆ serial ports for increasing the system performance and computational power. Then the implementation of embedded real-time operating systems （RTOS） by us is discussed in detail. In this system, we adopt two kinds of parallel structures controlled by RTOS for parallel processing of algorithms. The experimental results show that exploitive period of the system is short, and maintenance convenient. Thus it is suitable for real-time image processing and can get satisfactory effect of image recognition.
基金ACKNOWLEDGEMENT This work was supported in part by the Na- tional Natural Science Foundation of China under Grants No. 61271192, No. 60932004 the National High Technology Research and Development of China （863 Program） under Grant No. 2013AA013401 and the National Basic Research Program of China under Grant No. 2013CB329204.
文摘Abstract： Real-time digital service and mul- timedia service upstream transmission in Dig- ital Signal Processing （DSP）-based Orthogo- nal Frequency Division Multiplexing-Passive Optical Network （OFDM-PON） is experimen- tally demonstrated with Centralised Light Sou- rce （CLS） configuration in this paper. After transmitted over 25 km Standard Single Mode Fibre （SSMF） with -16.5 dBm optical power at receiver, the Bit Error Rate （BER） is 9.5 ×10^-11. The implementations of digital domain up-conversion and down-conversion based on Field Programmable Gate Array （FPGA） are int- roduced, which can reduce the cost of In-ph- ase and Quadrature （IQ） radio frequency mix- ers utilised at transmitter and receiver. A car- rier synchronization algorithm is implemented for compensating carrier offset. A channel eq- ualization algorithm is adopted for compen- sating the damage of channel. A new structure of Frequency Synchronization Unit （FSU） des- igned in FPGA is also proposed to cope with the frequency shifting at receiver.
基金supported by National Natural Science Foundation of China(No.10975114)
文摘The instability of terahertz（THz）plasma waves in two-dimensional（2D）quantum electron gas in a nanometer field effect transistor（FET）with asymmetrical boundary conditions has been investigated.We analyze THz plasma waves of two parts of the 2D quantum electron gas：gated and ungated regions.The results show that the radiation frequency and the increment（radiation power）in 2D ungated quantum electron gas are much higher than that in 2D gated quantum electron gas.The quantum effects always enhance the radiation power and enlarge the region of instability in both cases.This allows us to conclude that 2D quantum electron gas in the transistor channel is important for the emission and detection process and both gated and ungated parts take part in that process.
文摘In this paper, we proposed a new concept: depth of drowsiness, which can more precisely describe the drowsiness than existing binary description. A set of effective markers for drowsiness: normalized band norm was successfully developed. These markers are invariant from voltage amplitude of brain waves, eliminating the need for calibrating the voltage output of the brain-computer interface devices. A new polling algorithm was designed and implemented for computing the depth of drowsiness. The time cost of data acquisition and processing for each estimate is about one second, which is well suited for real-time applications. Test results with a portable brain-computer interface device show that the depth of drowsiness computed by the method in this paper is generally invariant from ages of test subjects and sensor channels (P3 and C4). The comparison between experiment and computing results indicate that the new method is noticeably better than one of the recent methods in terms of accuracy for predicting the drowsiness.
基金The Project of Development on Technology for Offshore Waste Final Disposalthe Project of Investigation of Large Swell Waves and Rip Currents and Development of the Disaster Response System
文摘A wave forecasting system using FUNWAVE-TVD which is based on the fully nonlinear Boussinesq equations by Chen(2006)was developed to provide an accurate wave prediction in the Port of Busan,South Korea.This system is linked to the Korea Operational Oceanographic System(KOOS)developed by Park et al.(2015).The computational domain covers a region of 9.6 km×7.0 km with a grid size of 2 m in both directions,which is sufficient to resolve short waves and dominant sea states.The total number of grid points exceeds 16 millions,making the model computational expensive.To provide real-time forecasting,an interpolation method,which is based on pre-calculated results of FUNWAVE-TVD and SWAN forecasting results at the FUNWAVE-TVD offshore boundary,was used.A total of 45 cases were pre-calculated,which took 71 days on 924 computational cores of a Linux cluster system.Wind wave generation and propagation from the deep water were computed using the SWAN in KOOS.SWAN results provided a boundary condition for the FUNWAVE-TVD forecasting system.To verify the model,wave observations were conducted at three locations inside the port in a time period of more than 7 months.A model/model comparison between FUNWAVE-TVD and SWAN was also carried out.It is found that,FUNWAVE-TVD improves the forecasting results significantly compared to SWAN which underestimates wave heights in sheltered areas due to incorrect physical mechanism of wave diffraction,as well as large wave heights caused by wave reflections inside the port.
文摘A novel matching method for simultaneous multi-target recognition is proposed by jointly considering target's prior scattering knowledge and the polarization parameters of radar echoes. The matching coefficients are calculated for the judgment. MATLAB simulations show that several targets can be accurately recognized simultaneously, and a high recognition probability can be achieved in Monte Carlo simulations. The total execution time can be remarkably reduced in the Field Programmable Gate Array (FPGA) implementation of the matching procedure.
基金Supported by the National Natural Science Foundation of China(61271113)
文摘A binary tree representation is designed in this paper for optimization of wave digital filter（WDF）implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree representation at first.This WDF binary tree can then be transformed to several topologies with the same implication,since the WDF adaptors have a symmetrical behavior on their ports.Because the WDF implementation is related to field programmable gate array（FPGA）resource usage and the cycle time of emulation,choosing aproper binary tree topology for WDF implementation can help balance the complexity and performance quality of an emulation system.Both WDF-FPGA emulation and HSpice simulation on the same circuit are tested.There is no significant difference between these two simulations.However,in terms of time consumption,the WDF-FPGA emulation has an advantage over the other.Our experiment also demonstrates that the optimized WDF-FPGA emulation has an acceptable accuracy and feasibility.
文摘We propose a novel optical method for glucose measurement based on difuse photon-pair density wave(DPPDW)in a multiple scattering medium(MSM)where the light scattering of photon-pair is induced by refractive index mismatch between scatters and phantom solution.Experi-mentally,the DPPDW propagates in MSM via a two frequency laser(TFL)beam wherein highly correlated pairs of linear polarized photons are generated.The reduced scattering coefficientμ2s and absorption coefficientμ2a of DPPDW are measured simultaneously in terms of the amplitude and phase measurements of the detected heterodyne signal under arrangement at different dis-tances between the source and detection fibers in MSM.The results show that the sensitivity of glucose detection via glucose-induced change of reduced scattering coefficient(δμ′2)is 0.049%mM^(-1)in a 1%intralipid solution.In addition,the linear range ofδμ′2s vs glucose concentration implies that this DPPDW method can be used to monitor glucose concentration continuously and noninvasively subcutaneously.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61605248 and 61505261)
文摘GHz single-photon detector(SPD)is a crucial part in the practical high speed quantum key distribution(QKD)system.However,any imperfections in a practical QKD system may be exploited by an eavesdropper(Eve)to collect information about the key without being discovered.The sine wave gating SPD(SG-SPD)based on InGaAs/InP avalanche photodiode,one kind of practical high speed SPD,may also contain loopholes.In this paper,we study the principle and characteristic of the SG-SPD and find out the filtering loophole of the SG-SPD for the first time.What is more,the proof-of-principle experiment shows that Eve could blind and control Bob's SG-SPD by exploiting this loophole.We believe that giving enough attention to this loophole can improve the practical security of the existing QKD system.GHz single-photon detector(SPD)is a crucial part in the practical high speed quantum key distribution(QKD)system.However,any imperfections in a practical QKD system may be exploited by an eavesdropper(Eve)to collect information about the key without being discovered.The sine wave gating SPD(SG-SPD)based on InGaAs/InP avalanche photodiode,one kind of practical high speed SPD,may also contain loopholes.In this paper,we study the principle and characteristic of the SG-SPD and find out the filtering loophole of the SG-SPD for the first time.What is more,the proof-of-principle experiment shows that Eve could blind and control Bob's SG-SPD by exploiting this loophole.We believe that giving enough attention to this loophole can improve the practical security of the existing QKD system.
基金Project supported by the National Natural Science Foundation of China （Grant No 60407001） and the National Science Foundation for Post-doctoral Scientists of China （Grant No 20060390246）.
文摘All-optical XNOR and AND logic gates using four-wave mixing （FWM） and cross-gain modulation （XGM） in a single semiconductor optical amplifier （SOA） with improved dynamics are simultaneously realized. By numerical simulation, the effects of the input optical wave powers and injection current on the critical factors of the logic gate performances, such as the ON-OFF contrast ratio, the power-output level of the logic ＇1＇, and the difference between power outputs of the logic ＇1＇, are investigated in detail. In addition, the effect of the counter-propagating CW pump on the gain recovery is analysed.
