基于FAHP-RS和证据推理的雷达信号特征提取评估

针对当前雷达辐射源信号特征提取评估的研究不够深入,评估方法单一和缺乏科学性等问题,提出一种新的评估方法。基于构建的雷达辐射源信号特征提取评估指标体系,首先采用模糊层次分析法和粗糙集理论分别得到主客观权重,并建立优化模型进行权重融合,然后采用证据推理方法融合指标和权重,最后基于综合置信度完成方案排序。仿真实验表明,该评估方法可用来选出最符合用户需求的方案,与改进TOPSIS评估方法的比较结果说明了所提出方法的有效性和优越性。     

一种基于脉冲样本图和模糊理论的雷达辐射源识别

在现代信号密集环境中,传统的雷达信号特征描述方式很难对复杂体制雷达辐射源进行描述和识别.因此提出了一种基于脉冲样本图和模糊理论的雷达辐射源识别算法,运用格贴近度的模糊识别算法进行雷达辐射源识别.该方法省略了特征提取过程,简化了处理环节,仿真结果表明,这种方法具有很高的识别准确率.     

基于理想排序的雷达信号识别效能评估方法

当前对雷达辐射源信号识别效能评估的研究处于起步阶段,没有一种很好的评估方法对其进行评估.为此,论文提出一种基于AH P-I2TOPSIS的雷达辐射源信号识别效能评估方法.该方法主要在以下三点对传统区间TOPSIS方法进行改进,以消除逆序问题:利用AHP方法计算指标权值;利用理论极值确定绝对正负理想点;利用区间距离计算评估方案到正负理想点的距离并改进贴近度计算方法,并将AHP-I2TOPSIS方法应用于雷达辐射源信号识别效能评估中得到新的雷达辐射源信号识别效能评估方法.最后通过评估实例证明论文所提方法能有效解决逆序问题,并能很好地应用于雷达辐射源信号识别效能评估中.     

雷达辐射源信号脉内特征分析

脉内特征提取是新型雷达辐射源信号识别的关键问题。本文提出一种新的雷达辐射源信号脉内特征提取和识别方法．将雷达辐射源脉冲信号的分形维数作为识别脉内调制方式的分类特征,这些特征包含了雷达辐射源信号幅度、频率和相位等的变化和分布信息,反映了雷达辐射源信号脉内调制规律,理论分析和仿真实验结果都证明了这些特征具有对噪声不敏感的良好特性．通过10种典型雷达辐射源信号的特征提取和分类识别的实验结果表明,本文所提取的脉内特征类间距离大、类内距离小、正确识别率高．证实了本文方法的有效性。     

基于复杂网络的雷达辐射源信号脉内特征提取算法

针对现代电子战环境下雷达辐射源信号的高度密集、复杂调制、交叠概率大等特点,基于时域、频域、时频域以及其他数学变换域的信号分析方法仍然不能满足雷达辐射源信号分选识别的要求,结合雷达辐射源信号具有可分辨性的确定数据结构表示,受时间序列的复杂网络分析启发,提出一种基于复杂网络的雷达辐射源信号脉内特征提取算法。该特征提取算法首先采用相空间重构方法对信号频谱序列数据进行预处理,将重构后的信号序列转换至复杂网络域进行表征;其次,通过复杂网络建模及其统计特征分析,研究雷达脉内信号时间序列动力学微观特性,从而挖掘信号的有效特征参数;最后,在不同噪声环境下,实现雷达辐射源信号序列的特征参数的分类性能及其准确性分析。仿真结果表明,所提取的特征参数在低信噪比环境下具有良好的抗噪能力和不错的聚类质量,验证了基于复杂网络时间序列分析的信号特征提取方法的可行性,为进一步丰富刻画雷达辐射源信号提供了有效的技术支持和手段。     

雷达辐射源信号识别效能评估的I2TOPSIS方法

针对雷达辐射源信号识别效能评估方法杂乱,指标模糊等问题,提出一种基于I2TOPSIS雷达辐射源信号识别效能评估方法。该方法主要在以下三点对传统区间TOPSIS方法进行改进:利用熵值计算指标权值;利用理论极值确定正负理想点;利用区间距离计算评估方案到正负理想点的距离,并将I2TOPSIS方法应用于雷达辐射源信号识别效能评估中得到一种新的雷达辐射源信号识别效能评估方法。最后通过与传统区间TOPSIS方法的评估对比实验证明新方法所得结果更合理、可行。      

基于Chirplet原子的雷达辐射源信号特征提取

特征提取是新体制雷达辐射源信号分选识别的关键技术.本文提出一种全新的雷达辐射源信号时频原子特征提取方法.在过完备多尺度Chirplet原子库基础上,采用匹配追踪(MP)方法对信号进行时频原子分解,并通过改进量子遗传算法(IQGA)降低MP搜索过程的时间复杂性,得到表示雷达辐射源信号特征信息的本征Chirplet原子.实验结果表明使用更少量的Chirplet原子可以得到比Gabor原子分解更准确的特征信息,证实了本文方法的可行性和有效性.     

基于小波变换的雷达辐射源信号特征提取

在小波多分辨分析的基础上提出一种对雷达辐射源信号进行脉内特征提取方法,该方法能够从信号中有效提取定量信息。将小波变换后低频逼近小波系数的能量分布熵,与经过尺度相关去噪计算后反映信号边缘的高频细节小波系数能量分布熵一起构成雷达辐射源信号的二维特征向量。通过对10种雷达辐射源信号的特征提取和分类仿真实验,结果表明：提取的样本特征在低信噪比下具有很好的抗噪性和可聚类性,证明了本文方法的有效性。     

基于波形相似性度量的雷达辐射源分选方法研究北大核心CSCD

针对基于提取雷达参数特征的分选方法中存在的特征提取困难、受噪声影响大以及对波形变化敏感等问题,依据相似性度量理论,文中提出了一种基于波形相似度测量的雷达辐射源分选方法。在完成对已有相似性度量算法研究的基础上,采用将夹角余弦算法、平均绝对差算法、动态滑动窗口算法相结合的方法,分别从雷达波形的整体和局部测量波形的相似度,实现雷达辐射源信号的配对分选。仿真结果表明,该方法能够克服传统分选方法的缺陷,相比基于信号互相关的分选算法,有效提高辐射源信号分选的准确率,对先验知识的依赖性不强,具有一定的抗噪能力。     

基于径向基概率神经网络的雷达辐射源信号识别

雷达辐射源信号识别是电子情报系统和电子支援系统的重要组成部分。文章提出一种基于径向基概率神经网络的雷达辐射源信号识别方法，通过对几种典型雷达辐射源信号复杂度特征提取和采用径向基概率神经网络分类器进行分类识别的实验结果表明，文章所提出的方法是有效的，能在较宽的信噪比范围内获得满意的识别率。     

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.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.