一种基于频率特征及动态窗长的钢琴调音算法

时域分析法是一种基本的语音分析方法。由于钢琴乐音模型与语音模型相似,故语音时域分析法可被用于钢琴乐音分析中。提出一种基于频率特征及动态窗长的钢琴基音识别时域算法,该算法能根据检测目标设计更为合适的分帧加窗模式,经过实验,可有效地提高检测精度及速度,在钢琴调音及单乐音基音识别应用中具有推广意义。     

基于样条函数Renyi熵的时间分集小波盲均衡算法

针对时间分集分数间隔判决反馈盲均衡算法(TD)计算量大、收敛速度慢的缺点,该文提出了一种基于样条函数Renyi熵的时间分集小波盲均衡算法。该算法直接把定义的样条函数Renyi熵作为代价函数用于TD的权向量更新,利用分数间隔获得更详细的信道信息;由正交小波变换降低输入信号的自相关性,以加快收敛速度;利用时间分集和判决反馈结构来降低多径衰落对通信质量的影响。水声信道盲均衡的仿真实验,验证了该算法的有效性。     

Random-valued impulse noise removal using adaptive dual threshold median filter

Noise detection and its removal is very important in the image processing. Detection of noise is very crucial and significant in random valued impulse noise because it does not hamper the image pixels uniformly. This paper presents a novel and unique concept of adaptive dual threshold for the detection of random valued impulse noise along with simple median filter at noise removal stage. Simulation results shows that an efficient noise detection leads to a superior quality of de-noised image as compared to existing adaptive threshold based image de-noising techniques. Proposed threshold computation is based on averaging of pixel values of window which enhances the PSNR of our system as compared to existing median filter based image de-noising methods.     

结合目标角运动参数估计的自适应波门设计

为了提高机电跟瞄平台的图像跟踪精度,针对波门跟踪方法,从脱靶量的预测、图像信息的滞后和伺服系统的动态精度3个方面入手,定性分析了它们对波门设计的影响.以此为基础,建立了目标空间角运动的Kalman运动模型,获得目标角运动参数的估计,并综合考虑图像传感器的滞后,推导了预测脱靶量的公式,完成了自适应波门的设计.最后以汽车为目标对常规波门和自适应波门进行了跟踪实验.     

真空电子器件输出窗次级电子倍增效应研究进展

真空电子器件在毫米波和太赫兹波频段具有大功率的天然优势,可用于构建高效率、大功率的毫米波和太赫兹辐射源,对高功率微波技术及太赫兹技术的发展具有十分重要的意义。输出窗是真空电子器件的关键部件,输出窗击穿是器件失效的主要原因之一,而次级电子倍增效应被认为是输出窗击穿的主要原因。本文梳理了目前分米波及厘米波波段真空电子器件输出窗的研究现状,在此基础上梳理了这一领域未来研究的主要发展方向,以期为未来真空电子器件向更高功率和更高频率等级发展提供参考。     

混沌保密通信系统中平凡密钥现象的探讨

论文从混沌动力系统的基本定义和性质出发,在对Logistic、Chebyshev等几种典型混沌动力系统的“平凡密钥”和“拟平凡密钥”现象进行深入分析的基础上,给出了该现象存在的广义解释,同时提出了几种克服该现象的实用解决方案,实验结果证明这些方案实时有效,实用性强。     

自适应时频同步压缩算法研究

提高时频分辨率对多分量非平稳信号的分析与重建具有至关重要的作用。传统的时频分析方法由于窗口固定,分析频率变化较快的信号时存在时频聚集性不高的问题,无法自适应分辨多分量信号。该文针对频率快速变化信号,利用信号的局部信息特征,提出一种自适应的时频同步压缩变换算法。该方法有效提升了已有同步压缩变换时频分辨率,特别适用于频率接近且快速变换的多分量信号。同时,利用可分性条件,该文提出利用局部瑞利熵值对自适应窗口参数进行估计。最后,通过对合成信号和实测信号分析,证明了所提方法的可行性,对分析和重建复杂非平稳信号具有重要意义。

     

Single face hallucination via local neighbor patches

Based on learning neighborhood patches a new single face hallucination method is proposed in this paper. In the proposed method, each input low-resolution (LR) position-patch and all patches in a local window centered at the same position of training images are used to hallucinate a high-resolution (HR) face patch, meanwhile two local similarity measurements between each input LR patch and all local LR and HR neighborhood patches of training images are computed to constrain the hallucination. Additionally, a residue image is estimated for the further improvement of the reconstructed result. Experimental results show that the proposed method can obtain superior or competitive results.     

Ultrasmall Semiconducting Polymer Dots with Rapid Clearance for Second Near‐Infrared Photoacoustic Imaging and Photothermal Cancer Therapy

Phototheranostic agents in the second near‐infrared (NIR‐II) window (1000–1700 nm) are emerging as a promising theranostic platform for precision medicine due to enhanced penetration depth and minimized tissue exposure. The development of metabolizable NIR‐II nanoagents for imaging‐guided therapy are essential for noninvasive disease diagnosis and precise ablation of tumors. Herein, metabolizable highly absorbing NIR‐II conjugated polymer dots (Pdots) are reported for the first time for photoacoustic imaging guided photothermal therapy (PTT). The unique design of low‐bandgap D‐A π‐conjugated polymer (DPP‐BTzTD) together with modified nanoreprecipitation conditions allows to fabricate NIR‐II absorbing Pdots with ultrasmall (4 nm) particle size. Extensive experimental tests demonstrate that the constructed Pdots exhibit good biocompatibility, excellent photostability, bright photoacoustic signals, and high photothermal conversion efficiency (53%). In addition, upon tail‐vein intravenous injection of tumor‐bearing mice, Pdots also show high‐efficient tumor ablation capability with rapid excretion from the body. In particular, both in vitro and in vivo assays indicate that the Pdots possess remarkable PTT performance under irradiation with a 1064 nm laser with 0.5 W cm^?2, which is much lower than its maximum permissible exposure limit of 1 W cm^?2. This pilot study thus paves a novel avenue for the development of organic semiconducting nanoagents for future clinical translation.     

SOC设计SI分析优化方法研究

基于集成电路规模与设计工艺不断发展的现状,SI问题日益突出和严重。系统介绍了SOC设计SI的概念、分类及产生基理,根据电路工程设计经验,重点阐述了在SOC设计SI的设计、优化、分析方法,介绍了利用EDA设计工具在芯片设计过程中对SI进行阻止、优化、分析的流程及方法,并对各种设计优化方法进行了利弊的对比分析,对芯片设计提供了很好的指导,结合EDA工具及合理的设计流程方法能够有效的保证芯片设计的良率和性能。