POWER OPTIMIZATION OF FINITE STATE MACHINE BASED ON GENETIC ALGORITHM

Using state assignment to minimize power dissipation and area for finite state machines is computationally hard.Most of published results show that the reduction of switching activity often trades with area penalty.In this paper,a new approach is proposed.Experimental results show a significant reduction of switching activity without area penalty compared with previous publications.     

基于FPGA的多通道雷达数据回放系统设计

为解决雷达实时信号处理功能及性能有效验证问题,文中设计并实现了一种宽窄带一体化、多通道雷达数据回放系统。该系统按雷达工作的时序和数据率将雷达回波数据发送至实时信号处理系统,从而对目标跟踪场景进行复现,实现雷达实时信号处理功能及性能的有效验证。系统硬件平台由磁盘阵列服务器与两块PCIe光纤板组成。基于Xilinx系列产品,结合系统特点对PCIe DMA控制流程及响应机制做进一步调整,实现了服务器到光纤板的雷达回波数据高速批量传输。根据雷达工作机制及回波数据结构,设计FPGA回放控制状态机及相关功能模块,严格按照雷达工作的时序和数据率使雷达回波数据由光纤板传输至实时处理系统。分别设计软件同步控制方法和硬件同步控制方法,保证多板卡数据回放的同步性。测试结果表明,该系统实现了宽、窄带雷达回波数据的板间同步回放,各数据类型分别支持6路并行数据通道,数据回放峰值速率可达1 920 MB·s^-1。文中系统可依托雷达原有硬件平台实现,无需增设板卡和线缆,具有良好的集成性与通用性,目前已被应用于某多功能相控阵雷达中。     

DB—5型光栅扫描电子束曝光机真空系统

本文介绍了我国自行研制的第一台生产实用型光栅扫描电子束曝光机的真空系统,包括系统设计、分子泵与离子泵的应用、全系统泵阀的可编程自动控制,以及为改善系统性能采取的一些措施。     

投影电视的新进展

随着HDTV技术的发展,室内电视的屏幕尺寸要求越来越大,投影电视的用量在增加。本文介绍了用CRT和LCD作投影器件的前投影和背投影电视系统。重点介绍了用量最多的CRT背投影和LCD前投影电视的技术进展。     

基于多特征联合处理的灵巧噪声干扰识别

灵巧噪声干扰已成为一种作用于新体制相参雷达的重要干扰类型.为了有效抑制该类干扰,提出一种基于多维特征的抗干扰方式.通过分析DRFM产生灵巧噪声干扰原理,建立目标与干扰信号模型;在分析对比两类信号特性的基础上,提取包络起伏参数、相位门限内概率及盒维数特征以表征目标与干扰信号在波形、相位及尺度信息上的差异;为了进一步提高干扰识别性能,加入表征信号复杂度的近似熵特征,分析表明该特征因子对噪声具有较强的鲁棒性;最后采用支撑向量机对提取的多维特征进行处理以实现灵巧噪声干扰的识别对抗.仿真实验表明,该方法对目标和干扰的正确识别率高且基本不受干噪比影响.     

机器学习系统毒化攻击综述

自机器学习被应用到许多关键性领域以来,机器学习系统的脆弱性也引起了人们的高度重视。其中,针对机器学习系统的毒化攻击得到了研究者的广泛关注,呈现了一些研究成果。因此,将系统地介绍当前机器学习系统毒化攻击的研究进展,对机器学习系统毒化攻击算法进行分类和总结,包括针对机器学习中的线性分类器、支持向量机、贝叶斯分类器和深度神经网络等几类常见模型的毒化攻击等攻击算法,目标是使现有的关于机器学习系统毒化攻击的研究成果更加清晰,为相关研究者的研究工作提供启发。     

A transition solvent strategy to print polymer:fullerene films using halogen-free solvents for solar cell applications

Inkjet printing is a mask-less non-contact deposition technique that is potentially suited for prototyping and manufacturing of thin-film polymer organic semiconductor devices from digital images. However new strategies are needed to achieve films with good macromorphology (i.e., high-fidelity footprint and uniform cross-section) and nanomorphology on unstructured substrates using a conventional ink-jet. Here we report a new transition solvent strategy to provide the desired film macromorphology and ultrafine nanomorphology in regioregular poly(3-hexylthiophene):phenyl-C₆₁-butyric acid methyl ester (P3HT:PCBM) model films, without using chlorinated solvents. This strategy employs a good volatile solvent in combination with a miscible poor solvent that is much less volatile, which is the reverse of the usual low−high boiling-point solvent method. The good solvent suppresses premature aggregation in the ink head. Its removal by evaporation on the substrate leaves the poor solvent that triggers early π-stacking ordering and/or gelation of the polymer matrix that immobilizes the printed fluid on the substrate, suppressing both contact-line depinning and evaporation-induced solvent flow effects. The resultant donor–acceptor nanomorphology is further improved by vacuum drying at an optimal rate that avoids bubble formation. We have systematically characterized P3HT:PCBM films deposited with different solvents and platen temperatures to identify key macro- and nano-morphology determining processes. High-performance printed P3HT:PCBM solar cells were realized. These findings are applicable also to other printing and coating techniques based on low-viscosity inks.     

Microcapacitors with controlled electrical capacity in the pF–nF range printed by laser-induced forward transfer (LIFT)

Micrometric-sized pixels of hybrid organic–inorganic thin films (Ag/parylene-C) have been printed by laser-induced forward transfer (LIFT) on flexible, cost-efficient substrates. Micrometric capacitors have been fabricated by laser printing such pixels together with silver nanoparticles (AgNP) paste. The AgNP paste has been deposited in the shape of square pads, acting as bottom electrode. This combination is suitable to be used in microelectronic circuits, as the electrical components exhibit controllable capacity in the pF–nF range. Electrical characterizations of the printed pixels demonstrate that the capacitors are fully operative and stable over time.     

基于UIO序列的类重要性度量

程序理解是测试和维护大规模面向对象程序的关键,选择程序的关键类优先开展分析是理解程序结构的一个有效的方法.为支持自动识别软件系统中的关键类,本文提出了一种基于UIO序列的类重要性度量方法.首先将软件系统抽象为一个以类为转换的有限自动机模型,随后求解该自动机的UIO序列,将该序列集合转化为状态转换树.通过递归计算状态转换树的节点复杂度求得类重要度.并在考虑异常传播的基础上改进了算法.最后通过实验验证了算法的有效性.     

铜粉添加量对铜酚醛树脂导电油墨性能的影响

以微米级铜粉为导电填料、酚醛树脂为粘接剂制备了导电油墨,并将该油墨以聚酰亚胺薄膜为基底,采用丝网印刷技术制备导电涂层。研究了铜粉添加量对铜酚醛树脂导电油墨的黏度、固含量以及导电涂层的微观形貌、电阻率和附着力的影响。研究表明,当铜粉添加量质量分数为70%时,制备的铜酚醛树脂导电油墨具有良好的性能,该导电油墨经丝网印刷得到的导电铜膜经低温固化后具有良好的电性能,其电阻率最低可以达到53.865×10–3Ω·cm。