机电设备的测试性验证方法初探

针对目前机电设备缺少有效的测试性验证方法的问题,提出了机电设备测试性验证方法与步骤.通过采取基于故障影响相对比值的样本分配方案,可以使试验结果更加真实、可信.根据注入故障必须不能破坏任何设备的原则,对于串联型机电设备中不宜直接进行故障注入的目标,可以通过后驱动技术进行故障注入.最后,对某串联型机电设备进行了测试性验证,...     

基于影响度的光电测量设备测试性验证试验样本抽取方法

为解决目前光电测量设备测试性验证试验中,因样本抽取方法不合理导致试验结论可信度低的问题,通过考虑危害度和故障扩散强度这两个与测试性相关的重要因素,提出了影响度的概念。从功能特征出发,构建功能模块-故障信息模型,利用该模型提出了基于影响度的样本抽取方法并给出试验抽取流程。此方法依据影响度相对比率,随机抽取出被测单元的故障样本,可较好地提高样本集代表性,确保试验结论置信度。并以某型光电测量设备中的时统终端单元为例,利用基于影响度的方法进行样本抽取,比较分析抽取结果证明该方法有效可行。     

基于OFDMA系统联合资源分配方案

针对多用户OFDMA系统,提出一种改进的比例公平资源分配算法。该算法采用分步法联合资源分配方案,分为子载波分配和功率分配两步进行,改进算法基于Wong算法,引入比例限制因子,在子载波分配环节,对剩余子载波的分配采用比例公平和最大化系统容量的算法,在用户中的功率分配环节,采用线性等式,大大降低了算法复杂度。仿真分析表明,改进算法不仅提高了系统吞吐量,而且降低了算法复杂度。     

基于影响度的光电测量设备故障诊断方法研究

针对目前光电测量设备故障诊断试验中,因样本抽取方法不合理导致试验结论可信度低的问题,通过考虑危害度和故障扩散强度这两个与测试性相关的重要因素,定义了影响度的概念。     

基于半监督学习生成对抗网络的人脸还原算法研究

基于大量训练样本生成高置信度图像的生成对抗网络研究已经取得一些成果,但是现有的研究只针对已知训练样本进行图像生成,而未将训练的参数用于训练样本之外的图像生成。该文设计了一种改进的生成对抗网络模型,在已有网络的基础上增加一个还原层,使得测试图像可以通过改进的对抗网络生成对应的高置信度图像。实验结果表明,改进的生成对抗网络参数可以应用到训练集之外的普通样本。同时本文改进了生成模型的损失算法,极大地缩短了网络的收敛时间。     

基于一致性预测器的卷烟牌号的鉴别研究

目前对于卷烟牌号的鉴别多应用一些传统分类算法,这些传统算法用于归纳一个通用规则的训练样本数据较少,造成分类模型的准确度较低,且预测结果没有置信度衡量,在高风险领域的应用不足。针对传统分类算法的局限性,提出了基于转导推理的一致性预测算法。通过探索待测数据和样本序列之间的内在联系,运用Kolmogorov算法的随机性理论建立一种置信度机制,并应用随机性检测函数对置信度进行估算,这样可以很好地对烟叶和成品卷烟进行定性判别和分类。     

改进的Faster R-CNN在车辆识别中的应用

随着人工智能技术的不断发展,利用深度学习进行车辆识别已经成为智能交通领域的热点。以更快速区域卷积神经网络(Faster R-CNN)模型为基础,利用BIT-Vehicle数据集定义车辆视觉任务,利用改进的困难样本算法加强对图像中远小目标车辆的特征提取,并改进NMS算法的置信度函数,动态调整置信度区间,对实际场景中的车辆图像进行测试。该方法可输入多尺度图像、能自主提取车辆特征,提高模型对小目标的判别能力,减少漏检情况,提升检测精度,加速模型收敛,鲁棒性较强。     

应对遮挡问题对DeepSORT进行轨迹拟合优化

检测跟踪范式是多目标跟踪的主要研究方向，也是自动驾驶汽车的主要应用框架。完善的检测跟踪范式可以在提高多目标跟踪精度的同时有效降低跟踪框的失真率。然而在现有的先进方法中，这种范式通常会遇到多目标重叠后的ID交换问题，严重影响跟踪精度和轨迹判断。为解决该问题，文中基于经典的DeepSORT算法提出改进方案。首先，在卡尔曼滤波器中添加跟踪框进行置信度的预测和更新，并按降序对更新后的置信度进行排列，在后续匹配中优先匹配预测置信度更高的跟踪目标；然后，比较预测置信度和检测置信度之间的差异，识别出置信度突变的目标，以进行跟踪轨迹的优化和剪枝；最后，使用余弦相似度和交并比（IoU）识别重叠目标，并对重叠目标中置信度最高的目标消失后的轨迹进行多项式轨迹拟合，以纠正错误的ID，完成精确匹配。实证分析结果表明，相比于目前多种先进算法，所提方法的ID交换次数为172，优于其他算法，验证了该算法的可行性和正确性。     

基于SVM与改进D-S理论电路板故障诊断算法

为了解决传统电路板故障诊断方法耗时长、难度大、准确度不高的问题,该文充分利用不同检测设备提供的电路板故障特征信息,提出基于支持向量机(SVM)与改进D-S证据理论相结合的电路板故障诊断算法。首先,将各证据体提供的故障数据输入SVM诊断模块,获取该证据体对各个故障模式的可靠度与加权系数;其次,利用"一对一"SVM多分类方法构造证据体对各个故障模式的基本概率分配;最后,对基本概率分配进行加权处理,完成基于D-S理论的多信息融合,获得故障诊断结果。实验结果表明,所提算法可以有效降低各证据体对诊断结论的冲突,增强正确诊断结果的信度,显著提高故障诊断准确率。     

半监督条件下基于朴素贝叶斯和Choi-Williams时频分布能量积累的雷达信号识别

针对非合作电子侦察雷达信号识别中先验信息残缺的问题,该文提出一种基于Choi-Williams时频分布(CWD)的改进半监督朴素贝叶斯的识别算法(ISNB)。首先对CWD进行降噪预处理,然后通过计算降噪后CWD不同时间下各频率采样值的积累量,从而得到CWD的能量积累量这一新特征;针对传统的半监督朴素贝叶斯(SNB)在更新训练样本集过程中会产生迭代错误的不足,通过在无标签样本集生成的置信度列表中选取置信度高的样本添加到有标签样本集中,再利用预测后的分类结果对分类器参数进行改进,进而构建改进的SNB分类器,有效解决了传统SNB算法分类精度低且分类性能不稳定的缺点。理论分析和仿真结果表明,所提方法相比于传统SNB算法均提高了3%左右;在相同信噪比下,相比于传统的主成分分析加支持向量机法,该算法具有更高的分类识别率和更好的分类性能。     

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.     

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.     

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.     

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.     

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.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-