Control charting methods for autocorrelated cyber vulnerability data

Control charting cyber vulnerabilities is challenging because the same vulnerabilities can remain from period to period. Also, hosts (personal computers, servers, printers, etc.) are often scanned infrequently and can be unavailable during scanning. To address these challenges, control charting of the period-to-period demerits per host using a hybrid moving centerline residual-based and adjusted demerit (MCRAD) chart is proposed. The intent is to direct limited administrator resources to unusual cases when automatic patching is insufficient. The proposed chart is shown to offer superior average run length performance compared with three alternative methods from the literature. The methods are illustrated using three datasets.     

n-C7H16/CCl4体系CVD-热解炭的形貌与形成机理

控制CVD工艺条件得到球状热解炭, 通过对沉积中间体的定性分析,证实了此过程中存在"缩聚机理". 运用热力学和晶体成核-长大理论,解释了温度对热解炭形貌和沉积过程的影响.     

Combinatorial initiated chemical vapor deposition (iCVD) for polymer thin film discovery

Initiated chemical vapor deposition (iCVD) is a technique used to synthesize polymer thin films and coatings from the vapor phase in situ on solid substrates via free-radical mechanisms. It is a solventless, low-temperature process capable of forming very thin conformal layers on complex architectures. By implementing a combinatorial approach that examines five initiation temperatures simultaneously, we have realized at least a five-fold increase in efficiency. The combinatorial films were compared to a series of blanket films deposited over the same conditions to ensure the combinatorial system provided the same information. Direct synthesis from the vapor phase allows for in situ control of film morphology, molecular weight and crosslinking, and the combinatorial system decreases the time required to find the relationship between these interrelated properties. Some coatings were tested for antimicrobial performance against E. coli and B. subtilis.     

A comparative study of the mechanical strength of chemical vapor-deposited diamond and physical vapor-deposited hard coatings

Four mechanical parameters of physical vapor-deposited (PVD) hard coatings were obtained, which were the residual strain, Young's modulus, film toughness, and interface toughness, concerning titanium aluminum nitride (TiAlN) and titanium nitride (TiN) coatings deposited on WC-Co substrates. The results were quantitatively compared with the author's previous trials for the case of chemical vapor-deposited (CVD) diamond coatings. Due to the significant difference in the mechanical properties between PVD hard coatings and CVD diamond coatings, it was necessary to develop new experimental techniques, which could properly evaluate those parameters for the case of PVD hard coatings. As a conclusion, film toughness of PVD hard coatings was surprisingly brittle. It was an order of magnitude smaller than that of CVD diamond coatings. In contrast, no significant difference was found in interface toughness between these different kinds of coatings. Concerning the residual strain, TiN had far larger level than the other two. These differences in mechanical properties were further discussed in relation to the difference in their wear behavior.     

On the effectiveness of the unit sample size for standard control charts: ARL VS. Aurl

In this paper we investigate the use of the average unit run length (AURL) as an important measure of the effectiveness of various quality control charting schemes. In particular we focus on its appropriateness for normally distributed processes that tend to produce units (or measurements) at slow rates. In our investigations with the standard Shewhart X? and R charts, as well as the CUSUM chart, AURL shows that a sample size of n=1 can yield the fastest means of detecting shifts.     

On monitoring industrial processes under feedback control

The concurrent use of statistical process control and engineering process control involves monitoring manipulated and controlled variables. One multivariate control chart may handle the statistical monitoring of all variables, but observing the manipulated and controlled variables in separate control charts may improve understanding of how disturbances and the controller performance affect the process. In this article, we illustrate how step and ramp disturbances manifest themselves in a single-input–single-output system by studying their resulting signatures in the controlled and manipulated variables. The system is controlled by variations of the widely used proportional-integral-derivative(PID) control scheme. Implications for applying control charts for these scenarios are discussed.     

用电泳沉积-电沉积联合法制备二氧化锆(YS Z)薄膜

先用电泳法在掺锶锰酸镧（La0.8Sr0.2MnO3-LSM）基片沉积一层钇稳定二氧化锆（yttria-stabilized zirconia-YSZ)薄膜,在烧结后的电泳薄膜上进行若干次电沉积和烧结。以封堵薄膜中孔隙进行。上述联合法综合了电泳沉积薄膜附着力强,烧结时不龟裂的优点和电沉积薄膜的颗粒细,易烧结性的优点,较好地解决了电化学沉积膜难以烧结致密的问题。制备出的薄膜致密性高,厚度为8～14um。     

Characterization of a large area scanning PECVD deposition system with small size RF electrodes

We have conducted characterization of a scanning plasma enhanced chemical vapor deposition (PECVD) system for producing controlled non-uniform deposition or etching profiles. Both self-bias and plasma potential showed that the plasma conditions were disturbed significantly when the source was very close to the chamber wall but electron temperature and ion density were not affected significantly. It was found that a very thin but long tail of parasitic deposition was present over the entire large substrate. To eliminate the parasitic deposition an aperture (plasma guarding house) was constructed and was found to eliminate the parasitic plasma deposition. Deposited silicon nitride and silicon oxide thin films using the plasma guarding house in the scanning PECVD system showed very good optical properties similar to those obtained in conventional deposition methods. No multilayer structure was observed in TEM analysis on these films.     

Epitaxial growth of Cu(100) and Pt(100) thin films on perovskite substrates

Pulsed laser deposition has been used to grow epitaxially oriented thin films of Cu and Pt on (100)-oriented SrTiO₃ and LaAlO₃ substrates. X-ray diffraction results illustrated that purely epitaxial Cu(100) films could be obtained at temperatures as low as 100 °C on SrTiO₃ and 300 °C on LaAlO₃. In contrast, epitaxial (100)-oriented Pt films were attained on LaAlO₃(100) only when deposited at 600 °C. Atomic force microscopy images showed that films deposited at higher temperatures consisted of 3D islands and that flat, layered films were obtained at the lowest deposition temperatures. Importantly, Cu films deposited at 100 °C on SrTiO₃(100) were both purely (100)-oriented and morphologically flat. Pt and Cu films displaying both epitaxial growth and smooth surfaces could be obtained on LaAlO₃(100) only by using a three-step deposition process. High-resolution transmission electron microscopy demonstrated an atomically sharp Cu/SrTiO₃ interface. The crystalline and morphological features of Cu and Pt films are interpreted in terms of the thermodynamic and kinetic properties of these metals.     

定向碳纳米管的化学气相沉积制备法

报道了一种简便有效的合成定向碳纳米管 (CNTs)的化学气相沉积 (CVD)制备方法。以铁为催化剂 ,乙炔为碳源 ,采用单一反应炉 ,直接在石英基底上沉积催化剂颗粒薄膜 ,成功合成了定向性好、管径均匀的高质量大密度的碳纳米管     

Deposits obtained by photolysis of hexamethyldisilane by ArF excimer laser (SiC thin film preparation by ArF excimer laser chemical vapor deposition, Part 2)

Thin films have been prepared by decomposition of hexamethyldisilane (HMDS) by ArF excimer laser at the fixed laser fluence of 800 J m⁻² and the substrate temperatures from 300 to 673 K and have been characterized using X-ray diffraction (XRD), scanning electron microscope observation, IR reflection spectroscopy and X-ray photoelectron spectroscopy. The XRD patterns showed the formation of 3C-SiC films but it is suggested that the films obtained at lower substrate temperature include organic functional groups, which might be derived from gaseous reaction products. Hydrogen existing in the form of Si-CH₂-Si could be decreased by decreasing the partial pressures of HMDS.     

波导材料二氧化硅厚膜的快速生长

采用火焰水解法（FHD）在Si片（ф4.5cm）上快速淀积疏松多孔的SiO2厚膜材料，淀积速率达8цm/min。然后将该材料分别在真空/空气气氛中高温致密化处理，获得了各种形态的二氧化硅厚膜。其中包括平整度好、光滑透明的玻璃态SiO2厚膜，该膜厚度达到40цm以上，完全适合制作平面光波导器件。最后，利用XRD、SEM、光学显微镜等仪器对SiO2膜的表面和膜厚进行了测试分析，并讨论了影响致密化SiO2厚膜结构的各种因素。     

Progressive Mean Control Chart for Monitoring Process Location Parameter

Control charts are widely used for process monitoring. They show whether the variation is due to common causes or whether some of the variation is due to special causes. To detect large shifts in the process, Shewhart‐type control charts are preferred. Cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts are generally used to detect small and moderate shifts. Shewhart‐type control charts (without additional tests) use only current information to detect special causes, whereas CUSUM and EWMA control charts also use past information. In this article, we proposed a control chart called progressive mean (PM) control chart, in which a PM is used as a plotting statistic. The proposed chart is designed such that it uses not only the current information but also the past information. Therefore, the proposed chart is a natural competitor for the classical CUSUM, the classical EWMA and some recent modifications of these two charts. The conclusion of this article is that the performance of the proposed PM chart is superior to the compared ones for small and moderate shifts, and its performance for large shifts is better (in terms of the average run length). Copyright © 2012 John Wiley & Sons, Ltd.     

Latent Structures-Based Multivariate Statistical Process Control: A Paradigm Shift

ABSTRACT

The basic fundamentals of statistical process control (SPC) were proposed by Walter Shewhart for data-starved production environments typical in the 1920s and 1930s. In the 21st century, the traditional scarcity of data has given way to a data-rich environment typical of highly automated and computerized modern processes. These data often exhibit high correlation, rank deficiency, low signal-to-noise ratio, multistage and multiway structures, and missing values. Conventional univariate and multivariate SPC techniques are not suitable in these environments. This article discusses the paradigm shift to which those working in the quality improvement field should pay keen attention. We advocate the use of latent structure–based multivariate statistical process control methods as efficient quality improvement tools in these massive data contexts. This is a strategic issue for industrial success in the tremendously competitive global market.     

Diffusion and adhesion properties of Cu films on polyimide substrates

Copper thin films were prepared on polyimide (PI) substrates by physical vapor deposition (PVD) and chemical vapor deposition (CVD). Titanium nitride (TiN) diffusion barrier layers were deposited between the copper films and the PI substrates by PVD. Auger electron spectroscopy compositional depth profile showed that TiN barrier layer was very effective in preventing copper diffusion into PI substrate even after the Cu/TiN/PI samples were annealed at 300 °C for 5 h. For the as-deposited CVD-Cu/PI, CVD-Cu/TiN/PI, and as-deposited PVD-Cu/PI samples, the residual stress in Cu films was very small. Relatively larger residual stress existed in Cu films for PVD-Cu/TiN/PI samples. For PVD-Cu/TiN/PI samples, annealing can increase the peeling strength to the level observed without a diffusion barrier. The adhesion improvement of Cu films by annealing treatment can be attributed to lowering of the residual tensile stress in Cu films.     

Ion assistance in epitaxial growth as a strategy to suppress twinning

Homoepitaxy on Ir(111) at 350 K through physical vapor deposition without and with ion assistance is compared in a scanning tunneling microscopy study. During growth without ion assistance thin Ir films on Ir(111) rapidly develop stacking faults such that for films of more than 50 atomic layers thickness the majority of the film surface displays twins. Ion assistance with 100 eV Ar⁺ at normal incidence as well as with 500 eV Ar⁺ at grazing incidence both effectively suppress stacking fault formation and twinning in the growing film. The mechanisms of twin suppression are identified.     

羟基磷灰石/生物玻璃复合涂层的研究

设计了适合在Ti6Al4V金属基体上制备涂层的生物玻璃，通过电泳沉积以及后续热处理在Ti6Al4V合金上制备了羟基磷灰石／生物玻璃复合涂层，实现了底层致密表层多孔的结构梯度。利用平底锥头法对涂层剪切强度进行了测试；利用SEM观察了其表面形貌；利用EPMA分析了复合涂层断面结构和组成。