Statistical Wavelet Subband Characterization Based on Generalized Gamma Density and Its Application in Texture Retrieval

The modeling of image data by a general parametric family of statistical distributions plays an important role in many applications. In this paper, we propose to adopt the three-parameter generalized Gamma density $({rm G}Gamma{rm D})$ for modeling wavelet detail subband histograms and for texture image retrieval. The advantage of ${rm G}Gamma{rm D}$ over the existing generalized Gaussian density (GGD) is that it provides more flexibility to control the shape of model which is critical for practical histogram-based applications. To measure the discrepancy between ${rm G}Gamma{rm Ds}$, we use the symmetrized Kullback-Leibler distance (SKLD) and derive a closed form for the SKLD between ${rm G}Gamma{rm Ds}$. Such a distance can be computed directly and effectively via the model parameters, making our proposed scheme particularly suitable for image retrieval systems with large image database. Experimental results on the well-known databases reveal the superior performance of our proposed method compared with the current existing approaches.      

Wavelet coding of volumetric medical images for high throughput and operability

This paper presents a new three-dimensional (3-D) wavelet-based scalable lossless coding scheme for compression of volumetric medical images. Aiming to improve the productivity of radiologists and the cost-effectiveness of the system, we strive to achieve high decoder throughput, random access to coded data volume, progressive transmission, and high compression ratio in a balanced design approach. These desirable functionalities are realized by a modified 3-D dyadic wavelet transform tailored to volumetric medical images and an optimized Rice code of very low complexity.     

Power optimization for maximum channel capacity in MIMO relay system

Introducing multiple-input multiple-output (MIMO) relay channel could offer significant capacity gain.And it is of great importance to develop effective power allocation strategies to achieve power efficiency and improve channel capacity in amplify-and-forward relay system.This article investigates a two-hop MIMO relay system with multiple antennas in relay node (RN) and receiver (RX).Maximizing capacity with antenna selection (MCAS) and maximizing capacity with eigen-decomposition (MCED) schemes are proposed to efficiently allocate power among antennas in RN under first and second hop limited scenarios.The analysis and simulation results show that both MCED and MCAS can improve the channel capacity compared with uniform power allocation (UPA) scheme in most of the studied areas.The MCAS bears comparison with MCED with an acceptable capacity loss, but lowers the complexity by saving channel state information (CSI) feedback to the transmitter (TX).Moreover, when the RN is close to RX, the performance of UPA is also close to the upper bound as the performance of first hop is limited.     

用于氨氮检测的三维微纳氨气传感芯片及系统研究

该文设计并制备了一种多层微结构的安培型氨气三维微纳传感芯片,并构建了以此微传感芯片为敏感单元的氨氮检测系统,探索了使用安培型氨气微传感器检测氨氮的方法。该微传感芯片采用微纳加工工艺制备,使用聚合物键合工艺在较低温度下实现了微传感器多层结构的封装。使用纳米铱作为传感器的敏感材料,其具有良好的电催化氧化能力,可使传感器具有较高的灵敏度。对Ag/AgCl微参比电极的稳定性进行了考察。使用自行设计的氨氮检测系统对氨氮样品进行检测,对微传感器的时间响应特性、浓度响应特性、重复性及选择性进行了测试和分析。实验结果表明,在0.5~10 mg/L的测试范围内,检测电流与氨氮浓度保持良好的线性,灵敏度为1.62 A/(mg/L),线性相关系数为0.995,重复性偏差为5.73%。同时,传感器显示出良好的选择性。     

高性能图像多级小波变换的硬件设计与实现

为满足基于小波变换的高速图像处理技术需求,在研究小波分析数理基础上,以Le Gall(5/3)小波为例,设计了一种结构简单、易于硬件高速实现的二维多级小波变换硬件架构。该设计抛弃了传统二维图像在二维多级小波变换时需要先将图像行变换和列变换分开处理,以及不同级变换需要分层处理思路。这种架构设计充分利用图像变换时像素的运算规则,在读取面阵图像2行数据后,就开始图像的行与列,以及不同级小波变换同时并行执行。此外在不同级小波变换中插入多级流水线,有效地提高了整个变换的时钟频率,整个变换采用VHDL语言在FPGA实现。仿真结果表明,该设计思路正确,所得到变换结果与理论计算完全一致。     

在“数字电子技术”教学中培养学生创新能力

＂数字电子技术＂课程在电类本科教学中起着重要作用。本文首先介绍了＂数字电子技术＂的课程特点和创新思维方法,然后详细阐述了基于创新思维方法的＂数字电子技术＂课程教学。教学实践表明：该教学方法能有效地培养学生的自学习惯和提出问题、分析问题、解决问题的能力,挖掘学生的创新潜力。     

基于嵌入式处理器指纹识别系统的设计和实现

研究采用嵌入式处理器实现指纹识别系统的软硬件设计方法,通过构造以微处理器AT91SAM7X256和MBF200指纹传感器模块为平台的硬件环境,实现了嵌入式指纹识别硬件系统的设计.微处理器选用内含丰富外设的AT91SAM7X256,降低了硬件成本.指纹识别系统选用μC/OS-Ⅱ作为嵌入式操作系统,指纹识别算法中主要介绍了基于图像匹配的指纹识别算法、基于Gabor函数的指纹图像增强算法和基于方向图滤波指纹特征提取算法等,实现了低成本,高可靠性多节点指纹识别系统的设计.     

Silicene Nanoribbons on an Insulating Thin Film

Silicene, a new 2D material has attracted intense research because of the ubiquitous use of silicon in modern technology. However, producing free-standing silicene has proved to be a huge challenge. Until now, silicene could be synthesized only on metal surfaces where it naturally forms strong interactions with the metal substrate that modify its electronic properties. Here, the authors report the first experimental evidence of silicene nanoribbons on an insulating NaCl thin film. This work represents a major breakthrough, for the study of the intrinsic properties of silicene, and by extension to other 2D materials that have so far only been grown on metal surfaces.     

浅谈单片机系统设计的可靠性

本文介绍了在设计单片机系统时应注意的问题 ,对电路设计和印制电路板设计作了较为详细的介绍     

某大口径火炮输弹一致性研究

基于区间参数的不确定性分析方法对某大口径火炮输弹一致性进行研究,分析输弹参数不确定性带来输弹动力学响应的变化。利用ADAMS软件建立输弹机动力学模型,根据输弹过程和输弹实验确定不确定参数及参数区间,采用基于统计信息的多体系统区间不确定分析方法计算得到输弹过程弹丸状态参数,并确定弹丸状态参数区间。数值算例结果表明,输弹机强制输弹阶段参数的不确定性对弹丸状态参数基本无影响,惯性输弹阶段参数的不确定性对火炮输弹一致性有很大影响。