抗几何攻击的鲁棒计算全息零水印算法

结合计算全息技术,提出一种新颖的抗几何攻击的鲁棒零水印算法.零水印构造过程中,先对小波变换后的宿主图像的低频子带进行分块,然后对每个分块进行奇异值分解并量化它们的最大奇异值,最后用得到的量化矩阵与全息水印构造零水印,并在IPR数据库注册获得版权保护.检测过程中,先用基于Zernike矩和不变质心的改进图像校正算法对几何失真图像进行校准,然后用校正后的图像进行水印检测.与传统的零水印算法及数字全息水印算法相比,本文算法具有更好的抗几何攻击性能.实验表明,该算法能有效地抵抗旋转,缩放、平移、翻转和旋转-缩放组合等几何攻击,同时对滤波、加噪声、JPEG 压缩、图像模糊、裁剪和对比度增强等常规攻击也有很强的鲁棒性.     

平稳随机信号AR模型的一种新观点

从平稳随机信号自相关的准周期性对AR模型进行了深入研究,提出平稳随机信号AR模型的一种新观点,即认为平稳随机信号的AR模型的成立不应基于信号熵原理,而应基于其自相关的准周期性,论文以此为基础,导出了许多熵原理AR模型无法得到的性质。     

基于随机逼近动态带宽分配的CAC研究

ATM网络中,基于动态带宽分配的CAC,即可以提高ATM网络资源的利用率又能保证业务的QoS要求。本文运用自适应随机逼近算法研究了ON／OFF信源模型的带宽估计及接入问题,数值计算的结果表明,随机逼近能较好地逼近实际值,与社会网络方法相比,随机逼近算法的特点是不需要离线训练,也不需要已准好的样本,这能在网络实际运行中自动调整自动收敛。     

Content Uniformity of a Low Dose Pharmaceutical Product

ABSTRACT

Optimum homogeneity and physical stability for a Roche compound (RO) low dose formulations (0,125 and 0.250 mg Tablets i.e. 0.07 to 0.14% w/w drug load, respectively) were achieved. Direct compression powder formulations were prepared by mixing the active drug substance with Starch 1500 (ST) to form an active pre-mix. Other ingredients were added subsequently. The final powder mix was subjected to a vibration of 4 Hz frequency using a specially designed segregation unit and content uniformity was assessed for these formulations. ST was considered superior to both lactose anhydrous and Avicel PH 102 in preparing homogeneous and physically stable mixes. Production-size batches of the product were successfully manufactured (Mean Drug content = 98 100%, RSV = 2%).     

Signal Quality Improvement Using a New TMSSE Algorithm: Application in Delamination Detection in Composite Materials

This paper introduces a novel method to improve the quality of ultrasonic phased array signals for localizing with accuracy delamination defects. The improvement is achieved by the introduction of a new threshold for the Shannon energy. In first, we have applied the threshold modified S-transform algorithm (TMST) in the case of ultrasound B-scan. Thereafter, we have adapted and applied the S-transform Shannon energy (SSE) algorithm in the field of ultrasonic testing. At last, we have proposed a novel algorithm based on threshold modified S-transform and Shannon energy (TMSSE) to increase the improvement of the ultrasound B-scan. A simulation study has been carried out simulating a composite material containing three defects in different positions in order to highlight the phenomenon of delamination. Experimental tests were performed on a sample of carbon fiber reinforced polymer composite material (CFRP) with a delamination defect close to the front face. Both experimental and simulated results show that the proposed method can improve the quality of ultrasound B-scan which enhances the localization of delamination defects.     

Spherical Geometry HOC Scheme to Capture Low Pressures within a Wake

The solution of the pressure Poisson equation in spherical polar coordinates using a higher order compact (HOC) scheme effectively captures low pressure values in the wake region for viscous flow past a sphere. In the absence of an exact solution, the fourth-order of accuracy of the results is illustrated. Low pressure circular contours occur in the wake region when the Reynolds number $Re = 161$, which is a lower value than previously identified in the literature, and closed pressure contours appear in two regions when $Re = 250$.     

曲线造型的新方法研究

本文提出可通过对形状参数的适当选择来实现对极限曲线形状调整和控制的三参数四点细分曲线造型方法,并对其收敛性进行了分析,同时给出并证明了曲线C~1到C~2连续的充分条件。数值试验证明所给方法是有效的。     

Studies on Low Altitude Clouds Over New Delhi,India Using Lidar

This study reports the altitude distribution of physical and optical properties of clouds in the lower troposphere over the urban tropical region Delhi using an UV (355 nm) lidar which is capable of operating in both day and night time. Most of the low altitude clouds are observed above the planetary boundary layer during the observation period. The low altitude cloud bottom and top height varies between 0.58 ± 0.21 and 1.5 ± 0.61 km respectively during the observation period. The depolarization ratio of the observed clouds varies from 0.18 ± 0.01 to 1.2 ± 0.58. The role of the atmospheric region below the cloud in the growth process of the cloud cell is studied. Cloud turbulence is derived to show its role in maintaining the strength of the cloud.     

一类中立型时滞系统新的鲁棒稳定性准则

本文考虑了一类具有时变时滞和非线性扰动的中立型系统的鲁棒稳定性问题.基于Lyapunov稳定性理论和自由权矩阵方法,得到保证系统鲁棒渐近稳定的新的充分条件.所得结果同时依赖于离散时滞和中立时滞,并用LMIs表示.由于对Lyapunov泛函导数采用了无保守的估计,因此所得结果具有较小的保守性,能够给出时变时滞较大的允许时...     

Cost Prediction of a Turbofan Engine Using the Robust Partial Least Squares Method

In recent years,the cost of engines has become increasingly important to engine manufacturers,who are consistently faced with major problems on how to reduce cost to a minimum.Cost has become a decisive factor for aircraft design.To control the continual rapid increased cost,engine cost prediction is indispensable early in the design phase.But the cost data of an aircraft engine is small;we introduce the Robust Partial Least Squares Method in solving this problem,and reducing or removing the effect of outlying data points,which is different from the Classical PLS.We use the MATLAB software doing several simulations;results and analysis of a real turbofan engine data set show the effectiveness and robustness of the Robust PLS method.The Robust PLS method can effectively be used to estimate Turbofan Engine cost with reasonable accuracy.     

一种基于自验证公钥的门限代理签名方案的安全性分析

Xue和Cao提出了一种基于自验证公钥的门限代理签名方案,然而,该方案是不安全的。给出了对该方案一种攻击：攻击者获得一个合法的原始签名人发送给代理签名人的签名了的授权证书以及代理签名人生成的一个有效的代理签名后,能够伪造出一个新的对相同消息的代理签名,而原始签名人变为攻击者自己,由于验证者并不能验证代理签名人到底是代表谁生成了代理签名,这样,攻击者就获得了与合法原始签名人相同的权益。特别地,代理签名人代表原始签名人生成的门限代理签名可以被转化为普通的门限签名。分析了该方案存在安全漏洞的原因并提出了改进措施,改进措施能有效地弥补原方案存在的安全缺陷。     

Low Concentration Monitoring of Exhaust Gases Using a UV-Based Optical Sensor

The development of an ultra-violet (UV) differential optical absorption spectroscopy (DOAS) fibre-optic sensor for the monitoring of vehicle exhaust gases is described in this paper. Experimental results describing the operation of this sensor with NO₂, SO₂ , and NO are shown. These experimental results are compared with existing published spectroscopic absorption measurements. It is shown that the minimum detectable concentration of NO₂ is 1 ppm, SO ₂ is 1 ppm, and NO is 26 ppm. The sensor was found to have a low susceptibility to interference between the detection of these gases     

Identification of Different Vapors Using a Single Temperature Modulated Polymer Sensor With a Novel Signal Processing Technique

This paper reports on a novel temperature modulation technique to improve the ability of a single carbon black/polymer resistive sensor to discriminate, identify and characterize environmental pollutants. Such a sensor can be low cost, low-power consumption, highly reliable, and thus ideal for indoor gas monitoring. Here, a carbon black/polyvinylpyrrolidone film was deposited onto an SOI-CMOS microhotplate. A novel temperature modulation technique is proposed that allows the detection of vapors using a single chemoresistor. Identification and quantification of water, methanol and ethanol vapors with different concentrations (water: 0–6000 ppm, methanol: 1360–5430 ppm and ethanol: 2270–9080 ppm) are shown.      

Low Temperature Epitaxial Growth of Semiconductors Using Synchrotron Radiation as a Light Source

Results of our recent experiments relating to the synchrotron radiation (SR) excited growth of Ⅱ-V compounds using metalorganic sources are described. We discuss mainly the growth characteristics of films in addition to the characterization of the deposited films. ZnTe epitaxial layer without carbon and oxygen contamination is attainable even at room temperature using SR as a light source. The quantum yield for forming ZnTe molecules was estimated to be higher than 3%. Through these experiments, we propose that the SR-excited growth is a powerful technique for a novel low temperature growth of compounds.     

新型低成本玻璃纤维增强抗冲击复合材料研究

根据VARTM工艺要求,设计了含有活性稀释剂的新型环氧树脂体系,并以其粘度、氧指数、复合材料抗冲击性能和力学性能等为依据优化了其配方.研究了玻璃纤维表面处理对相应复合材料抗冲击性能和力学性能的影响,优化了表面处理剂的种类及配方.研究评价了一种新型3D机织织物VARTM工艺中树脂的流动性,发现采用该织物的复合材料抗冲击性能优良、损伤面积明显降低.在上述基础上确定了玻璃纤维增强低成本抗冲击复合材料体系,表征了该材料的基本理化性能、力学性能及环境适应性.     

Polymer Light-Emitting Diode Using a New Electrophosphorescent Cyclometalated Iridium Complex

A new iridium-based cyclometalated complex, namely bis (2-phenylpyridine-C², N') iridium (III) picolinate [(ppy)₂Ir(pic)] is synthesized and investigated as electrophosphorescent dopant in polymer-based organic light-emitting diodes. The photoluminescence emission from this complex is observed at 501 nm, with a shoulder at 526 nm. Poly(N-vinylcarbazole) (PVK) is used as host polymer and single-layer devices of PVK doped with (ppy)₂Ir(pic) complex are fabricated. Photoluminescence (PL) spectra of PVK films doped with different concentration of iridium complex were measured to study the possible energy transfer occurring between PVK to iridium complex. A predominant blue to a completely green shifted emission is observed when the doping concentration was increased from 0% to 5 wt%. Optical and atomic force microscopic images of the doped films indicate a smooth film formation when spin coated with chlorobenzene as a solvent as compared to chloroform. Electroluminescence spectra of ITO/PEDOT:PSS/PVK:(ppy)₂Ir(pic)/Al device resembles that of the PL spectra with emission at 507 nm and Commission Internationale de l'Eclairage (CIE) coordinates (0.29, 0.57).     

Image Denoising Using a New Implementation of the Hyperanalytic Wavelet Transform

Shift invariance associated with good directional selectivity is important for the use of a wavelet transform (WT) in many fields of image processing. Generally, complex wavelet transforms, e.g., the double-tree complex WT (DTCWT), have these useful properties. In this paper, we propose the use of a recently introduced implementation of such a WT, namely, the hyperanalytic WT (HWT), in association with filtering techniques already used with the discrete WT (DWT). The result is a very simple and fast image denoising algorithm. Some simulation results and comparisons prove the performance obtained using the new method.