文章研究了一种融合人工智能的音频信号降噪技术。首先,构建一个包含滤波方法、人工智能等关键组成部分的音频降噪框架。其次,针对音频降噪框架中自适应滤波与长短期记忆(Long Short Term Memory,LSTM)网络相结合的声音降噪方法,详细介...文章研究了一种融合人工智能的音频信号降噪技术。首先,构建一个包含滤波方法、人工智能等关键组成部分的音频降噪框架。其次,针对音频降噪框架中自适应滤波与长短期记忆(Long Short Term Memory,LSTM)网络相结合的声音降噪方法,详细介绍其数学原理和实现过程。最后,采用Noisex-92数据集对所提方法进行全面的测试与评估。结果表明,文章提出的方法在信噪比(Signal to Noise Ratio,SNR)和信号失真比(Signal Distortion Ratio,SDR)上均取得了显著提升。展开更多
This article presents an up-to-date tutorial review of nonlinear Bayesian estimation. State estimation for nonlinear systems has been a challenge encountered in a wide range of engineering fields, attracting decades o...This article presents an up-to-date tutorial review of nonlinear Bayesian estimation. State estimation for nonlinear systems has been a challenge encountered in a wide range of engineering fields, attracting decades of research effort. To date,one of the most promising and popular approaches is to view and address the problem from a Bayesian probabilistic perspective,which enables estimation of the unknown state variables by tracking their probabilistic distribution or statistics(e.g., mean and covariance) conditioned on a system's measurement data.This article offers a systematic introduction to the Bayesian state estimation framework and reviews various Kalman filtering(KF)techniques, progressively from the standard KF for linear systems to extended KF, unscented KF and ensemble KF for nonlinear systems. It also overviews other prominent or emerging Bayesian estimation methods including Gaussian filtering, Gaussian-sum filtering, particle filtering and moving horizon estimation and extends the discussion of state estimation to more complicated problems such as simultaneous state and parameter/input estimation.展开更多
This paper presents a terahertz（THz）band-pass filter using ultra-precision machining technology based on Chebyshev filter prototype.This iris inductive window coupled waveguide filter was designed by using 8 resonan...This paper presents a terahertz（THz）band-pass filter using ultra-precision machining technology based on Chebyshev filter prototype.This iris inductive window coupled waveguide filter was designed by using 8 resonant cavities with a center frequency of 345 GHz and a 7% bandwidth.The final design fulfills the desired specifications and presents the minimum insertion loss of 1.55 d B and the return loss of less than 15 d B at 345 GHz.The stop-band rejection is50 d B off the center frequency about 30 GHz,which means it has a good performance of high stop-band suppression.Compared with the recent development of THz filters,this filter possesses the characteristic of simple structure and is easy to machining.展开更多
In this work, in order to improve spatial recognition abilities for the long-term operation tasks of the assistant robot for the elderly, a novel approach of semantic region estimation is proposed. We define a novel g...In this work, in order to improve spatial recognition abilities for the long-term operation tasks of the assistant robot for the elderly, a novel approach of semantic region estimation is proposed. We define a novel graphbased semantic region descriptions, which are estimated in a dynamically fashion. We propose a two-level update algorithm, namely, Symbols update level and Regions update level. The algorithm firstly adopts particle filter to update weights of the symbols, and then use the Viterbi algorithm to estimate the region the robot stays in based on those weights, optimally. Experimental results demonstrate that our proposed approach can solve problems of the long-term operation and kidnapped robot problem.展开更多
A terahertz（THz） waveguide band-pass filter using an iris inductive window coupled structure was designed and fabricated.The filter was designed at0.22 THz with a pass band of 20 GHz.The measured results show that t...A terahertz（THz） waveguide band-pass filter using an iris inductive window coupled structure was designed and fabricated.The filter was designed at0.22 THz with a pass band of 20 GHz.The measured results show that the center frequency is 0.218 THz with a pass band of 0.205 THz to 0.231 THz,the minimum insertion loss is 1.26 d B at 0.224 THz,and the return loss is less than 13.1 d B.The stop-band suppression is65.6 d B at 0.193 THz and 51.8 d B at 0.243 THz,respectively,which means a good performance of high stop-band suppression.A good agreement exists between the measured S-parameters and the simulated ones,especially in the upper band.The proposed THz waveguide filter has potential applications in THz communications.展开更多
文摘针对无人机长期跟踪过程中尺度变换导致目标丢失和跟踪精度低的问题,提出了一种基于飞蛾扑火优化(moth-flame optimization,MFO)的尺度比例感知空间长期跟踪器。首先,设计了高斯初始化以代替飞蛾扑火优化算法的随机初始化策略,降低优化算法在跟踪过程中的计算复杂度,减少算力浪费;其次,结合快速梯度直方图特征,构建了改进的飞蛾扑火优化跟踪器;然后,为了解决无人机航拍长期跟踪中目标尺度变化的问题,设计了一种自适应尺度变换的判别尺度空间跟踪(discriminative scale space tracking,DSST)算法,进一步提出了一种尺度比例感知空间跟踪器,解决了尺度滤波器中因长宽比固定而导致的跟踪漂移;同时,分析了滤波器响应峰值在各背景下的变化情况,提出了一种能反映环境变化下跟踪置信度的指标,并通过置信度将MFO优化跟踪框架与尺度比例感知空间跟踪器相结合,解决了尺度变化与长期跟踪目标丢失的问题;最后,在无人机长期跟踪数据集上开展了性能验证。结果表明:提出的算法可有效防止漂移现象的发生,提升跟踪效率;与目前跟踪领域中12种同类文献算法进行对比可知,提出的算法精度较高,满足实时性,能够有效解决无人机长期跟踪下的尺度变化及目标丢失等问题。
文摘文章研究了一种融合人工智能的音频信号降噪技术。首先,构建一个包含滤波方法、人工智能等关键组成部分的音频降噪框架。其次,针对音频降噪框架中自适应滤波与长短期记忆(Long Short Term Memory,LSTM)网络相结合的声音降噪方法,详细介绍其数学原理和实现过程。最后,采用Noisex-92数据集对所提方法进行全面的测试与评估。结果表明,文章提出的方法在信噪比(Signal to Noise Ratio,SNR)和信号失真比(Signal Distortion Ratio,SDR)上均取得了显著提升。
文摘This article presents an up-to-date tutorial review of nonlinear Bayesian estimation. State estimation for nonlinear systems has been a challenge encountered in a wide range of engineering fields, attracting decades of research effort. To date,one of the most promising and popular approaches is to view and address the problem from a Bayesian probabilistic perspective,which enables estimation of the unknown state variables by tracking their probabilistic distribution or statistics(e.g., mean and covariance) conditioned on a system's measurement data.This article offers a systematic introduction to the Bayesian state estimation framework and reviews various Kalman filtering(KF)techniques, progressively from the standard KF for linear systems to extended KF, unscented KF and ensemble KF for nonlinear systems. It also overviews other prominent or emerging Bayesian estimation methods including Gaussian filtering, Gaussian-sum filtering, particle filtering and moving horizon estimation and extends the discussion of state estimation to more complicated problems such as simultaneous state and parameter/input estimation.
基金supported by the National Natural Science Foundation of China under Grant No.61434006
文摘This paper presents a terahertz（THz）band-pass filter using ultra-precision machining technology based on Chebyshev filter prototype.This iris inductive window coupled waveguide filter was designed by using 8 resonant cavities with a center frequency of 345 GHz and a 7% bandwidth.The final design fulfills the desired specifications and presents the minimum insertion loss of 1.55 d B and the return loss of less than 15 d B at 345 GHz.The stop-band rejection is50 d B off the center frequency about 30 GHz,which means it has a good performance of high stop-band suppression.Compared with the recent development of THz filters,this filter possesses the characteristic of simple structure and is easy to machining.
基金supported by the National Natural Science Foundation of China (61305103 and 61473103)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (51521003 )+1 种基金the Natural Science Foundation of Heilongjiang Province, China (QC2014C072 and F2015010)SelfPlanned Task (SKLRS201609B and SKLRS201411B) of State Key Laboratory of Robotics and System (HIT)
文摘In this work, in order to improve spatial recognition abilities for the long-term operation tasks of the assistant robot for the elderly, a novel approach of semantic region estimation is proposed. We define a novel graphbased semantic region descriptions, which are estimated in a dynamically fashion. We propose a two-level update algorithm, namely, Symbols update level and Regions update level. The algorithm firstly adopts particle filter to update weights of the symbols, and then use the Viterbi algorithm to estimate the region the robot stays in based on those weights, optimally. Experimental results demonstrate that our proposed approach can solve problems of the long-term operation and kidnapped robot problem.
基金Supported by the National Natural Science Foundation of China （ No. 60872123 ） and the Guangdong Provincial Natural Science Foundation （No. U0835001 ）.
文摘A terahertz（THz） waveguide band-pass filter using an iris inductive window coupled structure was designed and fabricated.The filter was designed at0.22 THz with a pass band of 20 GHz.The measured results show that the center frequency is 0.218 THz with a pass band of 0.205 THz to 0.231 THz,the minimum insertion loss is 1.26 d B at 0.224 THz,and the return loss is less than 13.1 d B.The stop-band suppression is65.6 d B at 0.193 THz and 51.8 d B at 0.243 THz,respectively,which means a good performance of high stop-band suppression.A good agreement exists between the measured S-parameters and the simulated ones,especially in the upper band.The proposed THz waveguide filter has potential applications in THz communications.
