一种基于双正交小波变换和格型矢量量化的视频编码算法

本文提出了基于双正交小波变换（ｂｉｏｒｔｈｏｇｏｎａｌｗａｖｅｌｅｔｔｒａｎｓｆｏｒｍ）和格型矢量量化（ＬＶＱｌａｔｔｉｃｅｖｅｃｔｏｒｑｕａｎｔｉｚａｔｉｏｎ）的视频编码算法。在该方案中，小波变换将图像分解成多分辨率（ｍｕｌｔｉｒｅｓｏｌｕｔｉｏｎ）的子带图像，多分辨率运动估值（ＭＲＭＥ，ｍｕｌｔｉｒｅｓｏｌｕｔｉｏｎｍｏｔｉｏｎｅｓｔｉｍａｔｉｏｎ）技术实现子带图像的帧间预测，格型矢量量化对预测差值子带图像进行编码，从而获得了性能较好的活动图像编码新算法。     

基于残差图像的ROI编码研究

与JPEG2000中的MAXSHIFT算法不同，本文将ROI编码与零树编码结合，给出一种基于残差图像的ROI编码算法RZ(residue zerotree）。RZ算法基于整数小波变换，对高压缩比下零树编码后ROI区域的残差图像作基于整数平方量化阈值的零树编码，并将所得残差数据熵编码后跟随原编码数据传输，可以实现ROI区域的有损或无损编码。实验结果表明，RZ算法实现了基于嵌入式零对小波变换（EZW）框架较低复杂度的ROI编码，可应用于基于网络的图像传输。     

基于BWT和FVQ的极低比特率图像编码算法

该文提出了一种基于双正交小波变换（ＢＷＴ）和模糊矢量量化（ＦＶＱ）的极低比特率图像编码算法。该算法通过构造符合图像小波变换系数特征的跨频带矢量,充分利用了不同频带小波系数之间的相关性,有效地提高了图像的编码效率和重构质量。     

使用变换域编码技术压缩SAR原始数据

首先分析了在合成孔径雷达（SAR）原始数据中通常使用的块自适应量化（BAQ）算法，然后在此基础上详细讨论了两种基于块自适应量化的变换域编码算法，即基于快速傅里叶变换块自适应量化（FFT-BAQ）和基于小波变换块自适应量化（WT-BAQ），并对这两种算法压缩得到数据解压缩获得图像与块自适应量化得到的图像进行分析比较，结果显示变换域编码技术能改善SAR原始数据压缩性能。     

一种基于小波系数重要图编码的图像压缩算法

提出了一种新的基于小波系数重要图编码的图像压缩算法。该算法根据量化后的波系数的特点进行了一种期望排序，然后舍掉序列后面大量的零值小波系数，从而得到一个波系数子集，能以少的小波系数来很好地逼近原始图像，省去了零树编码中零树结构带来的大量比特开销。实验表明，该算法与MPEG-4的静止图像压缩算法相比较，重构图像的峰值信噪比（PSNR）值在相同码率下有较大的提高。     

基于新的小波基函数的二相编码信号检测

构造了一种新的小波基函数，提出了一种基于连续小波变换（CWT）的检测方法，并以叠加高斯白噪声的二相编码信号为例进行了算法仿真。仿真结果表明，这种方法对较低信噪比下二相编码信号的检测效果良好，在信噪比为-6．7dB时仍然能够准确地识别出二相编码信号。     

SPECK图像编码的改进算法

为了解决SPECK（Set Partitioning Embedded Block Coder集合分裂嵌入块）算法占用大量存储空间的问题，给出了一种无链表SPECK图像压缩算法LSK。LSK编码算法不需要链表，算法简单编码速度很快，适合硬件实现。改进方法用状态表来代替链表保存编码的码块和信息，状态表中每个小波系数由2个比特来表示。图像数据以z字形扫描后的一维数组形式储存，这种方法计算高效，算法简单。文中小波变换采用9／7提升分解算法，量化为均匀标量量化。实验结果表明，该算法与SPECK相近，比SPIHT效果好。     

基于整型小波变换的遥感图像压缩

对给定的遥感图像采用基于“提升”（Lifing)算法的整型小波变换，然后对变换后的小波域图像进行编码。在小波域编码时，采用逐次近似量化和LZ77方法编码。当量化门限较高时，则有用EZW方法直接对小波域上的图像进行编码，当门限较低时，则对EZW编码后的残差信息进行LZ77编码，文章用上述方法实现了遥感图像的无损压缩，提高了图像的压缩效果。     

一种多分辨率图像混合编码方案

本文提出一种基于小波变换与神经网络的多分辨率图像混合编码方案，利用小波分解对图像的多分辨率表示来消除图像空间域和频率域的相关性，由于小波图像相邻行之间的复杂关系难以用线性表示式来描述，使用多层神经网络（ＭＬＮＮ）来确定这种未知关系。实验证明，神经网络非线性预测器性能优于线性预测器，对非线性预测后的差值图像用自组织特征映射（ＳＯＦＭ）码书进行矢量量化（ＶＱ）编码，编码图像主观质量好，压缩比高，算法简     

基于整数小波变换与双阈值交替的遥感图像压缩

提出一种基于双阈值交替的遥感图像编码（DTAC）算法。根据整数小波变换（IWT）分解后不同阈值上的重要系数分布状况，对重要系数相对集中的区间用整数平方代替2的整数幂（IPT）作为量化阈值，在其他阈值区间中仍使用IPT，然后对每个阈值平面上的重要系数采用统一的编码策略。实验表明，新算法具有较低编码复杂度，不仅支持单一码流下从有损到无损的遥感图像编码，而且峰值信噪比（PSNR）高于采用IWT的SPECK编码算法。     

Novel zero-Voltage-transition PWM DC-DC converters

A new family of zero-voltage-switching (ZVS) pulsewidth-modulated (PWM) converters that uses a new ZVS-PWM switch cell is presented in this paper. Except for the auxiliary switch, all active and passive semiconductor devices in the ZVS-PWM converters operate at ZVS turn ON and turn OFF. The auxiliary switch operates at zero-current-switching (ZCS) turns ON and OFF. Besides operating at constant frequency, these new converters have no overvoltage across the switches and no additional current stress on the main switch in comparison to the hard-switching converter counterpart. Auxiliary components rated at very small current are used. The principle of operation, theoretical analysis, and experimental results of the new ZVS-PWM boost converter, rated 1 kW, and operating at 80 kHz, are provided in this paper to verify the performance of this new family of converters.     

An investigation into warpages,stresses and keep-out zone in 3D through-silicon-via DRAM packages

This paper aims to measure and simulate the warpages of 3D through-silicon via (TSV) die-stacked dynamic-random-access-memory (DRAM) packages during the manufacturing process. The related die stresses and keep-out zone (KOZ) for the stacked dies in the packages at room temperature are further calculated with the validated simulation model. The out-of-plane deformations (or warpages) of the packages from the full-field shadow moiré are documented under temperature loading and found consistent with those from finite-element method (FEM). The results of the stresses and KOZs at the proximity of a single TSV for each die in the package at room temperature are presented. It is found that the sizes of KOZs in four-die stacked DRAM packages with and without epoxy molding compound (EMC) at room temperature are dominated by the horizontal pMOS transistors and more than double the size in wafer-level die. The sizes of KOZs at each die are similar in this four-die stacked DRAM package, even though the stresses at each die are apparently different.     

截尾卷积码的译码算法分析

介绍了截尾卷积码的循环维特比译码算法和BCJR译码算法，以及在循环维特比算法基础上改进的环绕维特比译码算法和双向维特比算法，最后对各种译码算法的性能进行了仿真分析。     

ASON BoD业务在线预测与带宽调整研究

文章提出了微粒群优化的3层BP神经网络在线3步预测智能光网络带宽按需分配(BoD)业务流量模型,并改进了微粒群优化算法.对适应值较差的一部分微粒施加随机扰动,然后评估扰动效果,接受进化同时以一定概率接受退化.按3步预测中的最大值分配带宽,降低了突发业务阻塞率.仿真结果表明,该预测模型适应突发性、多样性BoD业务流量的在线预测.     

A novel ZCZVT forward converter with synchronous rectification

A novel zero-current-zero-voltage transition (ZCZVT) forward converter with synchronous rectification (SR) is presented in this paper. The proposed converter is operating at 300kHz and processes the features of both zero-voltage transition (ZVT) at turn on and zero-current transition (ZCT) at turn off for the main switch. The auxiliary switch also achieves zero-current switching (ZCS). The flux of transformer can be reset without tertiary winding. The steady-state analysis and design considerations are investigated in detail in this work. Moreover, a self-driven synchronous rectification is also added to the ZCZVT forward converter to reduce the conduction losses of the output rectifier. For 48-V input and 12-V 100-W output, a prototype of the proposed converter for 300-kHz switching is built to verify the theoretical analysis. Finally, the power losses are well estimated. The overall efficiency of the proposed converter is achieved at 89% at full load.     

39 GHz室外微蜂窝信道测量、建模与仿真研究

基于39 GHz室外微蜂窝场景实测数据,开展了毫米波段路径损耗、阴影衰落和大尺度参数的建模与仿真研究.介绍了毫米波段喇叭旋转测量系统下空间交替广义期望最大化(Space-Alternating Generalized Expectation-maximization,SAGE)算法信号模型,优化的分簇算法与莱斯因子计算方法.基于SAGE提取多径参数,利用优化的分簇算法提取并分析了簇参数,包括簇内角度扩展、簇内时延扩展以及簇的数目,并根据测量结果验证了第三代合作伙伴计划(The 3rd Generation Partnership Project,3GPP)第五代(the 5th Generation,5G)移动通信标准推荐的仿真平台准确定性无线信道产生器(Quasi-Deterministic Radio Channel Generator,QuaDRiGa)在39 GHz的可用性.结果表明:在视距径下,方向性路损和全向路损在固定截距和浮动截距两种拟合方式下与自由空间路损模型接近;大尺度参数统计特性与基于毫米波的第五代集成通信移动无线电接入网络(Millimetre-Wave Based Mobile Radio Access Network for Fifth Generation Integrated Communications,mmMAGIC)、3GPP结论接近;视距径与非视距径的簇参数差别较小,且簇的个数较6 GHz下的频段更少.本文为5G毫米波39 GHz频段信道仿真和系统设计提供了重要的信道模型和参数.     

一种新型正激零电压零电流转换PWM DC/DC变换器

提出一种新型的零电压零电流转换(ZCZVT)的正激拓扑。拓扑工作频率为300kHz,能实现主开关管的零电压开通(ZVS)和零电流关断(ZCS),同时辅助开关管也能实现零电流关断(ZCS),且变压器的磁通复位不需要辅助绕组。文章进行了拓扑的稳态分析,并且讨论了谐振电路的参数设计。最后,在研制一台48V输入、12V/100W输出样机的基础上,实验验证这种新型正激ZCZVT PWM DC-DC变换器的软开关特性。     

Analysis of the electromagnetic inductive response of a void in aconducting-soil background

A lossless dielectric object situated in a lossy dielectric medium (soil) constitutes a void in a conducting background, which can be detected via an electromagnetic-induction (EMI) sensor operating at appropriate frequencies. The electromagnetic character of this void is dependent on the target and soil properties, as well as on the frequency of operation. We utilize the rigorous method of moments (MoM) and the approximate extended-Born technique to model this three-dimensional (3-D) problem. The modeling algorithms are discussed in detail, with a focus on efficient computation of the dyadic Green's function at the frequencies of interest. The MoM results are used to calibrate the accuracy of the approximate extended-Born solution, over a wide range of operating conditions. Furthermore, the computer simulations are used to perform a detailed phenomenological study     

STM/AFM nano-oxidation process to room-temperature-operatedsingle-electron transistor and other devices

Application of a scanning tunneling microscopy (STM) and an atomic force microscopy (AFM) to electron devices and an optical device are introduced in this paper. Using STM tip/AFM cantilever as a cathode, surfaces of a metal or a semiconductor are oxidized to form a few tens of nanometers-wide oxidized metal line or an oxidized semiconductor line, which works as an energy barrier for an electron. A single-electron transistor (SET), a photoconductive switch, and a high-electron mobility transistor (HEMT) are fabricated using this fabrication process. The fabricated SET operates even at high room temperatures and shows the large Coulomb gap and staircase of 200-mV periods and the large Coulomb oscillation periods of 406 mV. The fabricated photoconductive switch shows a ultra-fast response time, i.e., a full-width at half-maximum response of 380 fs at a bias voltage of 10 V. The drain current of HEMT was controlled by the oxidized semiconductor wire on the channel region formed by this fabrication process     

Novel zero-current-switching PWM converters

This paper presents a new family of pulsewidth-modulated (PWM) converters, featuring soft commutation of the semiconductors at zero current (ZC) in the transistors and zero voltage (ZV) in the rectifiers. Besides operating at constant frequency and with reduced commutation losses, these new converters have output characteristics similar to the hard-switching-PWM counterpart, which means that there is no circulating reactive energy that would cause large conduction losses. The new family of zero-current-switching (ZCS)-PWM converters is suitable for high-power applications using insulated gate bipolar transistors (IGBTs). The advantages of the new ZCS-PWM boost converter employing IGBTs, rated at 1.6 kW and operating at 20 kHz, are presented. This new ZCS operation can reduce the average total power dissipation in the semiconductors practically by half, when compared with the hard-switching method. This new ZCS-PWM boost converter is suitable for high-power applications using IGBTs in power-factor correction. The principle of operation, theoretical analysis, and experimental results of the new ZCS-PWM boost converter are provided in this paper to verify the performance of this new family of converters