基于4G网络的视频加密传输系统设计

设计了一种视频加密传输设备,利用HDMI或USB接口接收外部摄像机或DV机视频数据流,对视频流数据进行编码,再经过加密处理后,通过4G移动网络将加密压缩的视频流数据传送至服务端。当服务器远端有设备连接时,能接收并播放视频数据。该传输设备软件实现了视频采集编码、4G移动网络、数据加密、TCP/IP协议传输数据等模块,与远端服务器通过私有协议发送加密数据,验证了各模块的工作性能以及可靠性。     

一种基于H.264 CABAC的视频加密方案

基于块的数字视频编码一般包括运动估计、残差块变换和熵编码三个阶段。针对传统的视频加密方案是对第二阶段中的残差变换系数进行的加密,提出了一种基于H.264CABAC熵编码的视频加密方案。该方案充分利用了流密码加密简单、运算快的优点,将加密过程置于视频编码的第三个阶段。并利用可灵活配置的加密模块和密文反馈模式,增强加密的安全性。理论分析和实验结果表明,提出的算法具有计算简单、安全高效、易于实现、不改变视频格式和压缩效率的优点。     

结合零树的分形运动补偿编码算法的研究

当前的视频编码算法无论是使用小波变换、分形理论还是运动补偿技术，使用单一的编码算法总是存在着压缩效率与实时视觉的矛盾。至今为止，已提出的小波分形混合编码方法也没能很好地利用小波变换后系数的统计特性，压缩的效果不论是在压缩比PSNR或是可伸缩性上并不理想，为此，本文提出了一种小波域内基于零树特点的分形运动补偿混合编码算法。实验证明，该算法具有良好的压缩性能，并且在重建图像和拥有逼真的视觉特件，获得了可伸缩的能够渐进的传输的编码码流。     

网络高效安全数据传输方法设计

现行的网络安全传输方案中经典的方法分为对称加密和非对称加密2种。对称加密运算速度快但容易被攻击和破解;非对称加密算法复杂,不易被破解,但加密速度慢,不适宜传输大量的安全数据。通过对哈夫曼压缩方法研究可知,不同的数据文件经过哈夫曼压缩后可形成不同的少量数据的哈夫曼压缩编码表和压缩文件。通过对哈夫曼编码表进行非对称加密设计的方案,可以减少非对称加密算法加密的字节数,实现大数据量文件的非对称加密。同时通过对大数据文件的压缩,可以减少整个文件大小,提高网络传输效率。该方案已在多个网络安全传输项目中得到应用,完全能够满足网络传输安全要求。     

一种基于对象的可伸缩小波编码器

提出了一种基于任意形状对象的嵌入零树小波编码器。该编码器首先对任意形状对象做适形离散小波变换(SA-DWT),然后用适形预测嵌入零树小波(SA-PEZW)方法来同时编码变换后的形状和纹理信息,从而得到一个具有可伸缩性并且能够精确重构形状信息的码流。对标准测试库列进行了实验,结果证明该编码器具有较高的编码效率,性能良好。     

一种基于EZW的ROI图像联合压缩加密算法

提出一种基于EZW编码的ROI图像联合压缩加密算法,阐述了上下文修正和判决修正的原理及实现,对所提出算法的安全性进行了评估。对算法进行仿真,结果表明相对于原始图像压缩算法,该算法的重构图像基本具有相同的压缩效率;相较于提升系数的ROI方法,该算法采用小波域图像分割,不需要对ROI形状信息进行编码,并可灵活调整ROI与背景区域(BG)的重构质量;相较于区间分裂算术编码器而言,该算法采用自适应算术编码,可获得更好的安全性;结合比特平面编码技术,使用不同密钥对ROI不同小波分辨力的系数分别加密,实现分辨力选择性加密,以满足不同应用需求。     

H．264多安全级网络视频加密方案研究

为了满足网络多媒体在安全性和实时性上多样化的加密需求,同时为新一代的视频压缩编码技术提高安全保障。基于H．264视频编码标准和密码学原理,分析现有的视频加密算法性能,同时从安全性出发,面向网络视频服务需求制定多安全级网络视频加密方案。该方案针对不同网络视频提供安全、实时的服务,提高了网络资源利用率,对网络具有良好的适应性。同时也为新一代多媒体安全保护技术提供了新的思路。     

H.264/AVC标准中基于CABAC的数字视频加密研究

分析和总结了用于新一代视频编码标准H.264／AVC加密的候选域，在此基础上提出了一种新的基于CABAC（基于上下文的自适应二进制算术编码）的数字视频加密方案，并给出了2种安全加密操作：RCME（规则编码模式加密）和BCME（旁路编码模式加密）实现了残差系数码字、运动矢量差码字和帧内预测模式的加密保护。实验结果表明，该方案具有较好的安全性、编码效率和误码顽健性。     

混沌神经网络在数字压缩图像加密中的应用

提出了一种混沌神经网络加密压缩数字图像的算法.首先,将原始图像进行二维小波变换后,转换成小波域上的小波系数,然后对小波系数进行嵌入零树小波编码.接着,将码流中"1"的位置取出,存入一个矩阵中,对此矩阵进行混沌神经网络加密.该加密算法具有以下特征:速度快、无失真、安全性高.仿真试验结果表明,该算法能得到令人满意的结果.     

一种基于FMO置乱的视频加密算法研究

通过分析H．264提出的灵活宏块排序（FMO）的特点,提出了一种随机置乱FMO—map的视频加密方案。此方案通过产生一个随机顺序的码表来置乱FMO—map来达到视频流加密的效果,另外将加密后的随机置乱码表并行输出。通过分析证明此方案在安全性、压缩比改变率和计算复杂度方面都具有良好的性能,能使视频图像的传输具有较好的安全性和实时性。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

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正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its