AVS视频编码中分像素插值的SSE2优化方法

视频编码中分像素插值是运动补偿中比较复杂的算法,耗时较长.利用SSE2指令系统并行处理的特性,针对AVS视频编码的分像素插值部分提出一种优化算法.实验结果表明,该算法可使该模块的平均执行时间缩短为原来的1/3.     

Design of high efficiency dual-mode buck DC-DC converter

A buck DC-DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current,and it can operate with an input range of 4.5 to 30 V.At light load current,the converter operates in skip mode.The converter enters PWM mode operation with increasing load current.It reduces the switching loss at light load and standby state,which results in prolonging battery lifetime and stand-by time.Meanwhile, externally adjustable soft-start minimizes the inru...     

冲激超宽带雷达生命信号提取的新方法

冲激超宽带生命探测雷达中,传统的平均相消法不能有效去除直达波,从而影响目标回波信号的提取;同时对回波数据中呼吸、心跳信息的提取仍然基于FFT从频域上进行,因而呼吸信号谐波对心跳信号检测的干扰未得到很好解决.针对这两个问题,采用宽带互相关法对回波时延进行估计,然后提取各个回波时延序列的均值与方差作为特征量,采用C-均值聚类算法对回波进行分类,实现直达波与目标回波的分离;采用经验模态分解将目标回波时延序列分解成有限个固有模态函数,从时域上提取呼吸和心跳信号,从而避免呼吸谐波对心跳信号检测的干扰.     

云计算国内外发展现状分析

需求驱动、技术驱动和政策驱动三大驱动力给云计算的发展提供了极大助力。本文首先介绍了国内外云计算生态环境的发展现状,分析了云计算业务模式,最后给出了云计算的发展趋势。     

Optimization on configuration of surface conduction electron-emitters

In this work, a novel nanogap with inclined protrusion cathode in palladium strip fabricated by hydrogen absorption under high-pressure treatment is optimized for the surface conduction electron-emitter. Its field emission is sensitive to the geometry of surface conduction electron-emitters (SCE). For a specified emitter material, the SCE are further investigated by varying the thickness, tilted angle and gap of palladium (Pd). An optimal field emission efficiency with 80° tilted angle, 120 nm gap and 10 nm thickness of Pd is found for certain designed field emission efficiency. We further find that varying the emitter material work function of the emitter material from 5.12 eV to 3.9 eV will further improve the field emission property due to the increase of the emitted current.     

Plasma-enhanced flexible metal-insulator-metal capacitor using high-k ZrO2 film as gate dielectric with improved reliability

We demonstrate a new flexible metal-insulator-metal capacitor using 9.5-nm-thick ZrO₂ film on a plastic polyimide substrate based on a simple and low-cost sol-gel precursor spin-coating process. The surface morphology of the ZrO₂ film was investigated using scan electron microscope and atomic force microscope. The as-deposited ZrO₂ film under suitable treatment of oxygen (O₂) plasma and then subsequent annealing at 250 °C exhibits superior low leakage current density of 9.0 × 10⁻⁹ A/cm² at applied voltage of 5 V and maximum capacitance density of 13.3 fF/μm² at 1 MHz. The as-deposited sol-gel film was completely oxidized when we employed O₂ plasma at relatively low temperature and power (30 W), hence enhancing the electrical performance of the capacitor. The shift (Zr 3d from 184.1 eV to 184.64 eV) in X-ray photoelectron spectroscopy of the binding energy of the electrons towards higher binding energy; clearly indicates that the O₂ plasma reaction was most effective process for the complete oxidation of the sol-gel precursor at relatively low processing temperature.     

异构融合网络认证机制研究

移动通信和无线局域网的快速发展使两者的融合成为热点。描述了融合网络的场景和耦合方案,对现有融合网的认证机制缺点进行了分析,提出把传输层安全协议TLS引入到融合网认证中,并对该认证机制对融合网络安全的增强进行了详细描述和分析。最后搭建了融合网络的试验平台,测量了新的认证机制在执行时延、吞吐量以及能量耗费方面的性能。结果表明,新认证机制在大大增强了融合网络安全性的同时提高了网络的性能和效率。     

近地水平接地天线的数值分析

用矩量法（MoM）结合离散复镜像理论（DCIM）研究了有耗地面上方水平接地天线的性能以及天线之间的互耦。由离散复镜像理论得到了分层媒质中空域磁矢位格林函数和电标位格林函数的闭合表达式，避免了直接作索末菲积分。讨论了对接地点的处理方法，提出以集中加载的接地电阻来描述接地点地网特性，并在天线末端附加一个电流项，此外无须再寻求任何关于末端电流的终端条件。提出采用分段辛普森数值积分方法来计算检验源和展开源重合时的阻抗矩阵元素，最后给出了部分计算结果，并与文献数据进行了对比。     

集成于电流模降压型DC-DC变换器的电流采样电路

针对电流模降压型DC-DC变换器,提出了一种新颖的CMOS片上电流采样电路.该电路结构简单,易于集成,功率损耗小,且通过MOSFET的匹配使采样比例几乎不受温度、模型以及电源电压变化影响.并通过进一步的优化设计,使得响应速度更快,工作电压进一步降低.提出的采样电路在一款基于0.5μm CMOS工艺没计的单片电流模降压型DC-DC变换器中进行了验证.在2.5～5.5V的电压范围,0～2A的负载范围内芯片工作稳定,瞬态响应良好,且效率高达96%.     

P2P和CDN技术融合实现流媒体业务

P2P和CDN融合实现流媒体业务是一种高效实用的方案。本文首先对P2P和CDN技术的优缺点进行分析比较,指出二者融合的优势,然后介绍并分析了P2P和现有CDN融合实现流媒体业务的几种解决方案,并分别描述了各自的优缺点,最后提出一种适合运营商网络现状的P2PCDN流媒体方案建议。