共查询到20条相似文献,搜索用时 62 毫秒
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为了解决动目标检测过程中的盲速问题,通常采用参差周期法设计参差滤波器组来达到同时抑制杂波和推远盲速的效果。提出了一种基于梯度免疫算法的参差MTI滤波器优化设计。该算法利用免疫算法搜索最优参差码,有效地避免了传统遗传算法中的早熟问题。针对传统的遗传算法运算量较大的问题,引入了梯度算子缩小初始种群规模,使运算量大大减少。仿真结果验证了算法的可行性和有效性。 相似文献
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传统的遗传算法设计参差MTI滤波器的方法存在早熟、多样性下降等问题。针对上述问题,提出一种新的搜索最优参差码的方法,该方法是以免疫克隆选择算法为基础,经过克隆、重组、变异及选择操作,将个体竞争与种间协作相结合,并根据局部特征信息以一定程度干扰全局并行搜索进程。仿真实验结果表明,该方法可有效地避免种群退化的问题,且能够快速收敛到全局最优点,设计滤波器的第一零点深度提高了1.7dB以上。 相似文献
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参差时变动目标显示(MTI)滤波器是在强运动杂波背景下检测弱目标和缓解盲速问题的一种有效方法.选择适当参差码使参差时变MTI滤波器的第一零点尽可能浅,可在有效抑制杂波的同时避免陷入其中的弱目标丢失.本文采用了结合梯度的混合遗传算法(HGA)选择最优参差码,与标准遗传算法(SGA)相比,该算法只需要很小的种群规模.采用马尔可夫链方法证明了HGA是以概率1收敛的全局随机搜索算法.将该算法应用于米波雷达中,性能分析和仿真实验表明,基于混合遗传算法的杂波抑制滤波器设计是可行和有效的. 相似文献
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该文提出了一种用于多杂波背景下的低速弱目标检测的脉间参差滤波器优化设计,该算法采用脉间滑动脉冲的方式进行参差MTI滤波器设计,并利用与梯度结合的遗传算法搜索最优的脉冲重复周期排布组合,使滤波器第一零点尽可能浅,可在有效抑制杂波和同频干扰的同时避免陷入其中的弱目标丢失,同时该滤波器可形成多个凹口以滤去多种杂波,并将盲速推到三倍音速以外。采用梯度遗传算法对脉冲重复周期进行搜索,由于该算法所需初始种群规模小,与标准遗传算法相比复杂度大大降低。仿真结果和性能分析验证了算法的可行性和有效性。 相似文献
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一种基于优化参差比的改进MTI滤波器 总被引:1,自引:1,他引:0
杂波的抑制 ,无论是从抗干扰还是提高雷达系统改善因子来说都是必不可少的。抑制杂波的同时为了避免陷入盲速区的目标损失过大 ,提出了一种基于优化参差比的MTI滤波器 ,该滤波器可在杂波谱中心形成随杂波散射元均方根速度展宽的凹口以抑制杂波 ,并利用参差脉冲将盲速推到三倍音速以外 ,而且通过最优参差码的选择使第一零点尽可能的浅 ,从而防止陷入凹口的弱目标丢失 ,最后通过对搜索最优参差比的简化 ,使运算量至少减少一半。仿真结果和性能分析验证了该算法的可行性和有效性 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's. 相似文献
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It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory. 相似文献
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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. 相似文献
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A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working. 相似文献
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《中国通信》2014,(7)
正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks 相似文献