In recent years, researches on the attenuation theory of active sound control and the technique of adaptive active sound control have becn made independently. By optimizing the number and the positions of error sensor...In recent years, researches on the attenuation theory of active sound control and the technique of adaptive active sound control have becn made independently. By optimizing the number and the positions of error sensors, a relation between them is found in this paper. The method and the formulae for optimization are given. The factors affecting the attenuation effects are discussed. All theoretical results are verilied by experiments and the attenuation effects are satisfied.展开更多
This study investigates the use of dynamic a priori error information according to atmospheric moistness and the use of quality controls in temperature and water vapor profile retrievals from hyperspectral infrared ...This study investigates the use of dynamic a priori error information according to atmospheric moistness and the use of quality controls in temperature and water vapor profile retrievals from hyperspectral infrared （IR） sounders. Temperature and water vapor profiles are retrieved from Atmospheric InfraRed Sounder （AIRS） radiance measurements by applying a physical iterative method using regression retrieval as the first guess. Based on the dependency of first-guess errors on the degree of atmospheric moistness, the a priori first-guess errors classified by total precipitable water （TPW） are applied in the AIRS physical retrieval procedure. Compared to the retrieval results from a fixed a priori error, boundary layer moisture retrievals appear to be improved via TPW classification of a priori first-guess errors. Six quality control （QC） tests, which check non-converged or bad retrievals, large residuals, high terrain and desert areas, and large temperature and moisture deviations from the first guess regression retrieval, are also applied in the AIRS physical retrievals. Significantly large errors are found for the retrievals rejected by these six QCs, and the retrieval errors are substantially reduced via QC over land, which suggest the usefulness and high impact of the QCs, especially over land. In conclusion, the use of dynamic a priori error information according to atmospheric moistness, and the use of appropriate QCs dealing with the geographical information and the deviation from the first-guess as well as the conventional inverse performance are suggested to improve temperature and moisture retrievals and their applications.展开更多
In hearing physiological experiments and clinic tests,we need not only a signal processing system,but also a synchronous sound stimulator’ Most of stimulators we are now using are function generators which are indepe...In hearing physiological experiments and clinic tests,we need not only a signal processing system,but also a synchronous sound stimulator’ Most of stimulators we are now using are function generators which are independent to processing units,and can be controlled only by hand. Although some of them have ports through which they can be controlled by computer,but as they are designed for industrial aims,not for hearing research,most of them can’t generate the special waveforms we need. We use the TDT signal processing system and develop a software package have both usage. On the interface of the program we can control the sampling parameters and generate stimulating waveforms’展开更多
为了解决目前车内声场分区控制系统无法对声场相位信息进行较好控制,导致声场分区性能无法达到最优的问题,提出一种基于声强控制的自适应声场分区算法。通过测量初始和变化声学环境下车内的声传递函数(Acoustic Transfer Function,ATF)...为了解决目前车内声场分区控制系统无法对声场相位信息进行较好控制,导致声场分区性能无法达到最优的问题,提出一种基于声强控制的自适应声场分区算法。通过测量初始和变化声学环境下车内的声传递函数(Acoustic Transfer Function,ATF)和声强信息,建立暗区声强最小的目标函数,设定明区声强相位信息约束条件,进行仿真求解得到控制滤波器系数。在声学环境变化后,采用自适应算法更新控制滤波器系数,并对比不同方法的分区性能。实验结果表明,在保持声场重建精度不变的情况下,采用声强控制方法可使全频段的平均声对比度提升3.6 dB。由此验证只需输入初始声强参数信息,基于声强控制的自适应声场分区算法就能在车内声学环境发生变化时通过自适应迭代保持较好的分区性能。展开更多
For anti-jamming and anti-countermeasure techniques of the sonar receiver,the response characteristics of the automatic gain control(AGC)circuit and the survivability of the prime circuit under strong interference are...For anti-jamming and anti-countermeasure techniques of the sonar receiver,the response characteristics of the automatic gain control(AGC)circuit and the survivability of the prime circuit under strong interference are analyzed by simulations and experiments.An AGC simulation model based on the voltage control amplifier VCA810 prototype is proposed.Then static and dynamic simulations are realized with single frequency signal and linear frequency modulated(LFM)signal commonly used in the active sonar.Based on intense sound pulse(ISP)interference experiments,the real-time response characteristics of each module of the receiver are studied to verify the correctness of the model as well as the simulation results.Simulation and experiment results show that,under 252 dB/20μs ISP interference,the specific sonar receiver will produce sustained cut top oscillation above 30 ms,which may affect the receiver and block the regular sonar signal.展开更多
In both industrial and research areas of electronic engineering,Sound Source Localization for robot control has always been an interesting subject to be further studied.Under some dangerous situation,especially when a...In both industrial and research areas of electronic engineering,Sound Source Localization for robot control has always been an interesting subject to be further studied.Under some dangerous situation,especially when a special driver is required to implement a particular task,the device should be able to combine robotics control technology with Sound Source Localization,and take actions according to the different response patterns.In this research project,a multifunc-tional model driver,named "Mobile Island",has been designed and built up by integrating the Emulator 8051 micro-controller,Intel 8255 interfaces,some components and other necessary devices.The intelligent Mobile Island imple-mented by C language programs can operate under three control modes.In the sound control Mode 1,the model driver can detect and track a target by Sound Source Localization and then turn and move toward the destination.In the keypad control Mode 2,it can be controlled by a manual keypad.In the free run Mode 3,Mobile Island can move and turn by itself.When finding an object in front,it will turn away before moving forward again,so that it can avoid crashing on the obstacle.展开更多
文摘In recent years, researches on the attenuation theory of active sound control and the technique of adaptive active sound control have becn made independently. By optimizing the number and the positions of error sensors, a relation between them is found in this paper. The method and the formulae for optimization are given. The factors affecting the attenuation effects are discussed. All theoretical results are verilied by experiments and the attenuation effects are satisfied.
基金supported by GOES-R Algorithm Working Group Program and GOES-R High Impact Weather Project (Grant No NA10NES4400013)supported by the Korea Meteorological Administration Research and Development Program under Grant CATER 2006-2103the BK21 Project of the Korean Government
文摘This study investigates the use of dynamic a priori error information according to atmospheric moistness and the use of quality controls in temperature and water vapor profile retrievals from hyperspectral infrared （IR） sounders. Temperature and water vapor profiles are retrieved from Atmospheric InfraRed Sounder （AIRS） radiance measurements by applying a physical iterative method using regression retrieval as the first guess. Based on the dependency of first-guess errors on the degree of atmospheric moistness, the a priori first-guess errors classified by total precipitable water （TPW） are applied in the AIRS physical retrieval procedure. Compared to the retrieval results from a fixed a priori error, boundary layer moisture retrievals appear to be improved via TPW classification of a priori first-guess errors. Six quality control （QC） tests, which check non-converged or bad retrievals, large residuals, high terrain and desert areas, and large temperature and moisture deviations from the first guess regression retrieval, are also applied in the AIRS physical retrievals. Significantly large errors are found for the retrievals rejected by these six QCs, and the retrieval errors are substantially reduced via QC over land, which suggest the usefulness and high impact of the QCs, especially over land. In conclusion, the use of dynamic a priori error information according to atmospheric moistness, and the use of appropriate QCs dealing with the geographical information and the deviation from the first-guess as well as the conventional inverse performance are suggested to improve temperature and moisture retrievals and their applications.
文摘In hearing physiological experiments and clinic tests,we need not only a signal processing system,but also a synchronous sound stimulator’ Most of stimulators we are now using are function generators which are independent to processing units,and can be controlled only by hand. Although some of them have ports through which they can be controlled by computer,but as they are designed for industrial aims,not for hearing research,most of them can’t generate the special waveforms we need. We use the TDT signal processing system and develop a software package have both usage. On the interface of the program we can control the sampling parameters and generate stimulating waveforms’
文摘为了解决目前车内声场分区控制系统无法对声场相位信息进行较好控制,导致声场分区性能无法达到最优的问题,提出一种基于声强控制的自适应声场分区算法。通过测量初始和变化声学环境下车内的声传递函数(Acoustic Transfer Function,ATF)和声强信息,建立暗区声强最小的目标函数,设定明区声强相位信息约束条件,进行仿真求解得到控制滤波器系数。在声学环境变化后,采用自适应算法更新控制滤波器系数,并对比不同方法的分区性能。实验结果表明,在保持声场重建精度不变的情况下,采用声强控制方法可使全频段的平均声对比度提升3.6 dB。由此验证只需输入初始声强参数信息,基于声强控制的自适应声场分区算法就能在车内声学环境发生变化时通过自适应迭代保持较好的分区性能。
基金supported by the National Natural Science Foundation of China(10974154)the National Innovation Project of China for Undergraduates(101069935)
文摘For anti-jamming and anti-countermeasure techniques of the sonar receiver,the response characteristics of the automatic gain control(AGC)circuit and the survivability of the prime circuit under strong interference are analyzed by simulations and experiments.An AGC simulation model based on the voltage control amplifier VCA810 prototype is proposed.Then static and dynamic simulations are realized with single frequency signal and linear frequency modulated(LFM)signal commonly used in the active sonar.Based on intense sound pulse(ISP)interference experiments,the real-time response characteristics of each module of the receiver are studied to verify the correctness of the model as well as the simulation results.Simulation and experiment results show that,under 252 dB/20μs ISP interference,the specific sonar receiver will produce sustained cut top oscillation above 30 ms,which may affect the receiver and block the regular sonar signal.
基金This paper is an introduction of the Research Project of‘LEC254’,which is held by The Hong Kong University of Science and Technology (HKUST)
文摘In both industrial and research areas of electronic engineering,Sound Source Localization for robot control has always been an interesting subject to be further studied.Under some dangerous situation,especially when a special driver is required to implement a particular task,the device should be able to combine robotics control technology with Sound Source Localization,and take actions according to the different response patterns.In this research project,a multifunc-tional model driver,named "Mobile Island",has been designed and built up by integrating the Emulator 8051 micro-controller,Intel 8255 interfaces,some components and other necessary devices.The intelligent Mobile Island imple-mented by C language programs can operate under three control modes.In the sound control Mode 1,the model driver can detect and track a target by Sound Source Localization and then turn and move toward the destination.In the keypad control Mode 2,it can be controlled by a manual keypad.In the free run Mode 3,Mobile Island can move and turn by itself.When finding an object in front,it will turn away before moving forward again,so that it can avoid crashing on the obstacle.
