异质性地表土壤冻融循环监测网络的优化采样设计-以黑河祁连山山前地区为例

在黑河祁连山山前地区建立分布式的土壤温度/水分传感器监测网络,准确获取异质性地表的遥感像元真值,用于地表冻融状态分类及土壤水分定量反演算法的发展完善和真实性检验,以及两者的降尺度研究均具有重要意义。传感器监测网络节点的空间布局直接影响观测有效性及其数据质量,一种基于异质性地表的均值估计方法被用于空间节点的优化采样设计：即以地表温度为目标变量,将研究区划分为相对均质的若干层(子区域),计算各层及总体的变异函数参数作为代价函数的输入,通过最小化目标变量的估计方差,实现传感器网络节点在各层的空间分布,准确地捕捉区域内部的异质性。结果表明,分层后各层的异质性相对于总体都有所下降,优化的节点空间布局具有较好的属性代表性,对于异质性较强的局部区域,有较高的样本密度。     

基于Benford定律的高斯模糊篡改取证

针对自然图像篡改手段中常用的高斯模糊,提出一种基于Benford定律的模糊篡改图像真实性取证方法.通过借助DCT域AC系数的Benford模型分别对自然图像的3个通道进行统计,构造特征,根据篡改前后差异的显著性水平设定阈值进行判定,最后给出实验结果.     

Controller design and analysis for singularly perturbed switched systems with actuator saturation

This paper investigates the problems of controller design and stability analysis for singularly perturbed switched systems subject to actuator saturation. A set of well‐defined sufficient conditions for the existence of state feedback controllers is proposed, under which the closed‐loop system is locally asymptotically stable for arbitrary switching law as long as the singular perturbation parameter is sufficiently small. With the obtained controller, the estimation problem of stability bound and basin of attraction of the closed‐loop system is reduced to solving a convex optimization problem. A numerical example and a hydraulic servo position system are used to illustrate the obtained results. Copyright © 2016 John Wiley & Sons, Ltd.     

Infrared Polarization and Intensity Image Fusion Algorithm Based on the Feature Transfer

The features of infrared polarization and intensity images are not finely transferred to the fused image by using traditional fusion algorithms, which leads to a severe blur of the fused image. This study proposes a new infrared polarization and intensity image fusion algorithm based on the feature transfer. First, the contrast features of the infrared polarization image are extracted by the multiscale average filter decomposition with help of standard deviation constraint. The texture features of infrared polarization images are retrieved via non-subsample-shearlet transform at the same time. Second, the difference of the features is measured using the similarity index, which is used as the transfer weight for the infrared polarization feature images during the later phase of the image fusion. Finally, the fused image is obtained by the superimposition of the infrared intensity image and feature images, which are created from the infrared polarization image. The experimental results demonstrated that the proposed method is able to transfer the features of both the infrared intensity image and the polarization image into the fused images. It performs well on both subjective and objective image quality.     

嵌入式磨削加工主动测量仪数据管理技术研究

针对嵌入式磨削加工主动测量控制系统的功能要求,提出了应用数据库对系统中大量数据进行管理的方案。对WinCE系统下常用嵌入式数据库的存取性能做了对比测试,并最终确定选用SQLite数据库进行数据管理。结合SQLite数据库在磨削加工主动测量控制系统中的应用,给出了磨削加工主动测量仪的数据库结构及其在Visual Studio 2008集成开发环境中的实现过程。研究结果表明,此方案的设计能够满足磨削加工主动测量仪对数据存取的实时性与一致性需求,对于磨削加工主动测量仪的研究和发展有着重要意义。     

无线传感器网络中基于闭合环包围的边界节点检测

由于无线传感器网络中可能会出现覆盖漏洞,导致网络无法提供高质量的数据,所以需要检测边界节点以准确找到覆盖漏洞进行修复。已有研究大多是通过传感器的坐标或者依据大量节点信息进行检测, 现提出算法通过检测每个节点的邻居节点是否能形成包围检测节点的闭合环来判别当前节点是否为边界节点。该算法使得节点能够仅基于小邻域的信息自主地决定它是否是边界节点,使其适用于节点分布不均匀的网络中。仿真实验验证了该算法在识别准确率、降低通信量等方面的有效性。     

Real-time confocal microscopic observations on human corneal nerves and wound healing after excimer laser photorefractive keratectomy

PURPOSE: Corneal wound healing after excimer laser photorefractive keratectomy (PRK) passes through a series of characteristic stages which have earlier been defined by means of histological, histochemical, and biochemical approaches. We investigated the potential of confocal microscopy to verify morphological changes in human corneas in vivo after PRK. METHODS: Ten corneas of eight patients that had earlier undergone PRK were examined at different postoperative time points (7 days-34 months). One of the PRK patients was examined sequentially three times. Three additional corneas, which had earlier undergone corneal grafting surgery and then were subjected to excimer laser photoastigmatic keratectomy (PARK), were studied as well. Seven healthy untreated corneas served as controls to define the normal morphology of human cornea. A tandem scanning confocal microscope (TSCM) was used to generate real-time images of the corneas on an S-VHS videotape. The images were either digitized and further processed or the individual video frames were produced with a video printer. RESULTS: Seven days post-PRK in vivo confocal microscopy revealed the presence of morphologically immature surface epithelial cells. Delicate nerves, activated keratocytes and deposition of extracellular light-reflecting scar tissue were perceived. The epithelium appeared normal one month post-PRK. Ongoing activation of the anterior stromal keratocytes along with extracellular scar tissue were detected. We also observed increasing numbers of regenerating subepithelial nerve leashes with somewhat twisted pattern. Highly reflective, presumably activated keratocytes were no longer detected 6-7 months post-PRK. Hypercellularity with scar tissue could still be found up to 30 months post-PRK. Only one cornea examined 34 months post-PRK showed normal keratocyte morphology and recovery of the anterior stroma. However, the morphology of subepithelial nerves was still somewhat abnormal. The two corneal grafts examined 11 or 32 months post-PARK exhibited a normal-appearing epithelium but considerable stromal hypercellularity and extracellular scar deposition. The subepithelial nerves were poorly regenerated in one eye and fairly well detectable in the other. The third graft examined 15 months post-PARK revealed the presence of enlarged surface epithelial cells and dense stromal scarring but no nerves. CONCLUSION: TSCM clinically confirms the earlier histological data on healing of excimer laser wounds. It offers a distinct improvement in the assessment of excimer laser-treated corneas, as it enables cellular details and nerves to be perceived in vivo. In addition the thickness of the stromal scar can be be measured for e.g. planning of phototherapeutic keratectomy.     

发酵鹿肉制品的发酵特性与工艺配方优化

以鹿肉和猪肉为原料,在植物乳杆菌Lp、双歧杆菌Bb、乳酸链球菌St和高效干酵母菌Bs的综合发酵作用下,研究发酵中水分、pH值、挥发性盐基氮、亚硝酸盐含量、氨基酸含量和过氧化值随时间变化的规律。通过四因素三水平正交试验和重复验证试验得最佳工艺参数为:粉状菌种Bs和St质量配比为1:1、二者总接种量为0.3%、Lp接种量为0.5×107,发酵温度25℃,发酵时间24h;发酵鹿肉制品主要原料质量比为猪肉:鹿肉=6:4,猪肥膘10%,马铃薯淀粉9%,葡萄糖8%。