Nonrigid registration of 3-d multichannel microscopy images of cell nuclei.

We present an intensity-based nonrigid registration approach for the normalization of 3-D multichannel microscopy images of cell nuclei. A main problem with cell nuclei images is that the intensity structure of different nuclei differs very much; thus, an intensity-based registration scheme cannot be used directly. Instead, we first perform a segmentation of the images from the cell nucleus channel, smooth the resulting images by a Gaussian filter, and then apply an intensity-based registration algorithm. The obtained transformation is applied to the images from the nucleus channel as well as to the images from the other channels. To improve the convergence rate of the algorithm, we propose an adaptive step length optimization scheme and also employ a multiresolution scheme. Our approach has been successfully applied using 2-D cell-like synthetic images, 3-D phantom images as well as 3-D multichannel microscopy images representing different chromosome territories and gene regions. We also describe an extension of our approach, which is applied for the registration of 3D + t (4-D) image series of moving cell nuclei.     

一种集成ΣΔ 小数频率合成器的双通道多模全球导航卫星系统接收机设计

本文给出了一种72mW的集成ΣΔ 小数频率合成器的高集成度双通道多模全球导航卫星系统接收机的设计,接收机覆盖GPS L1和北斗B1、B2、B3频段。接收机采用TSMC 0.18μm工艺,封装类型为3毫米?3毫米48脚封装。在没有片外低噪声放大器的情况下,噪声系数小于5.3dB,北斗B2、B3频段通道增益为105dB,GPS L1和北斗B1频段通道增益为110dB.镜像抑制dB.两个通道在的锁相环在偏离载波1MHz的频率处相位噪声为-115.9dBc和-108.9dBc。尽管两个不同的导航信号可以同时接收,在低功耗模式下,芯片实现了全球导航卫星系统多个频段的兼容,方便了用户的使用。     

Image reconstruction using interval simulated annealing in electrical impedance tomography

Electrical impedance tomography (EIT) is an imaging technique that attempts to reconstruct the impedance distribution inside an object from the impedance between electrodes placed on the object surface. The EIT reconstruction problem can be approached as a nonlinear nonconvex optimization problem in which one tries to maximize the matching between a simulated impedance problem and the observed data. This nonlinear optimization problem is often ill-posed, and not very suited to methods that evaluate derivatives of the objective function. It may be approached by simulated annealing (SA), but at a large computational cost due to the expensive evaluation process of the objective function, which involves a full simulation of the impedance problem at each iteration. A variation of SA is proposed in which the objective function is evaluated only partially, while ensuring boundaries on the behavior of the modified algorithm.     

Low-Complexity High-Rate Reed--Solomon Block Turbo Codes

This letter considers high-rate block turbo codes (BTC) obtained by concatenation of two single-error-correcting Reed-Solomon (RS) constituent codes. Simulation results show that these codes perform within 1 dB of the theoretical limit for binary transmission over additive white Gaussian noise with a low-complexity decoder. A comparison with Bose-Chaudhuri-Hocquenghem BTCs of similar code rate reveals that RS BTCs have interesting advantages in terms of memory size and decoder complexity for very-high-data-rate decoding architectures.     

The effect of the ionosphere on remote sensing of sea surface salinity from space: absorption and emission at L band

The purpose of this work is to examine the effects of Faraday rotation and attenuation/emission in the ionosphere in the context of a future remote sensing system in space to measure salinity. Sea surface salinity is important for understanding ocean circulation and for modeling energy exchange with the atmosphere. A passive microwave sensor in space operating near 1.4 GHz (L-band) could provide global coverage and complement in situ arrays being planned to provide subsurface profiles. However, the salinity signal is relatively small and changes along the propagation path can be important sources of error. It is shown that errors due to the ionosphere can be as large as several psu. The dominant source of error is Faraday rotation but emission can be important     

基于LabVIEW虚拟仪器技术的分布式速度检测系统

设计一种分布式的速度检测监控系统.系统以单片机及外围电路采集速度数据,通过RS 485总线把各测试点速度数据发送给PC机,在PC端利用LabVIEW软件编程实现各检测点速度数据的存储、处理、显示及远程监控等功能.将单片机与虚拟仪器技术结合应用,克服了常规运动物体速度检测中普遍存在的技术复杂、不易远程观测等缺点.实验结果表明该系统成本较低,精度较高,运行稳定可靠.     

Noise reduction in rhythmic and multitrial biosignals with applications to event-related potentials

A new noise reduction algorithm is presented for signals displaying repeated patterns or multiple trials. Each pattern is stored in a matrix, forming a set of events, which is termed multievent signal. Each event is considered as an affine transform of a basic template signal that allows for time scaling and shifting. Wavelet transforms, decimated and undecimated, are applied to each event. Noise reduction on the set of coefficients of the transformed events is applied using either wavelet de- noising or principal component analysis (PCA) noise reduction methodologies. The method does not require any manual selection of coefficients. Nonstationary multievent synthetic signals are employed to demonstrate the performance of the method using normalized mean square error against classical wavelet and PCA based algorithms. The new method shows a significant improvement in low SNRs (typically <0 dB). On the experimental side, evoked potentials in a visual oddball paradigm are used. The reduced-noise visual oddball event-related potentials reveal gradual changes in morphology from trial to trial (especially for N1-P2 and N2-P3 waves at Fz), which can be hypothetically linked to attention or decision processes. The new noise reduction method is, thus, shown to be particularly suited for recovering single-event features in non- stationary low SNR multievent contexts.     

“空-空”和“地-空”导弹武器系统雷达导引头的研制和技术发展特点(二)

研究了"空-空"和"地-空"导弹雷达导引头的研制特点和发展趋势,并预测了今后的发展前景;对不同时代雷达导引头进行了分类,阐述了在主动雷达导引头研制过程中出现的主要问题及其解决途径,指出了主动雷达导引头的改进方向。     

室内定位技术及应用综述

室内定位技术作为当前的研究热点,对军事、经济以及人们的日常生活产生了深远的影响。文中首先介绍了室内定位技术的应用背景以及发展方向,以及室内环境进行定位面临的主要难点。然后介绍了目前主要的定位算法,包括邻近信息、场景分析和几何定位算法,以及各种算法衍生出来的各种定位技术。最后指出了室内定位技术亟待解决的问题,以及下一步进行相关研究的突破口。     

考虑链路负载均衡和容量限制的WDM光传送网保护设计

网络的生存性是WDM光传送网设计时必须考虑的问题.在叠加(Overlay)模式的网络构架中,由于光路之间存在的依赖性,物理网络的单链路失效可能会造成虚拓扑不连通而使上层网络(SDH、ATM或IP)无法使用自身的恢复机制来恢复受影响的业务,因此虚拓扑在嵌入物理拓扑时必须避免发生这种情况.本文提出的VTMPD算法就是针对这一问题的保护设计算法.此算法同时考虑了物理链路的负载均衡和容量限制.我们还给出了VTMPD算法和已有的DAP算法的性能对比,测试数据表明VTMPD算法优于已有的DAP算法.