A high quality and small shadow size visual secret sharing scheme based on hybrid strategy for grayscale images

Many secret sharing schemes for digital images have been developed in recent decades. Traditional schemes typically must deal with the problem of computational complexity, and other visual secret sharing schemes come with a higher transmission cost and storage cost; that is, each shadow size is m times as big as the original secret image. The new (2,n) secret sharing scheme for grayscale images proposed in this paper is based a combination of acceptable image quality using block truncation coding (BTC), high compression ratio discrete wavelet transform (DWT) and good subjective performance of the vector quantization (VQ) technique. Experimental results confirm that our proposed scheme not only generates a high quality reconstructed original image but also generates small, random-like grayscale shadows.     

VSS软件开发中的版本控制

Windows平台下使用VSS开发的典型环境是基于C/S架构,以一个VF开发的学生成绩管理系统为例,介绍了VSS的服务器配置、客户端配置及使用。     

LMS类自适应算法性能比较与仿真

对LMS类变步长自适应算法进行讨论和分类，通过仿真实验，分别对各类算法性能进行分析并得出各算法的优缺点。     

Modified methods of designing sliding surface in variable structure systems

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Adaptive sliding mode control for MIMO nonlinear systems based on fuzzy logic scheme

In this study an indirect adaptive sliding mode control (SMC) based on a fuzzy logic scheme is proposed to strengthen the tracking control performance of a general class of multi-input multi-output (MIMO) nonlinear uncertain systems. Combining reaching law approach and fuzzy universal approximation theorem, the proposed design procedure combines the advantages of fuzzy logic control, adaptive control and sliding mode control. The stability of the control systems is proved in the sense of the Lyapunov second stability theorem. Two simulation studies are presented to demonstrate the effectiveness of our new hybrid control algorithm.     

Improvement of biohydrogen production from brewery wastewater: Evaluation of inocula,support and reactor

This work explores the production of biohydrogen from brewery wastewater using as inoculum a culture produced by natural fermentation of synthetic wastewater and Klebsiella pneumoniae isolated from the environment. Klebsiella pneumoniae showed good performance as inoculum, as evaluated using assays of between 9 and 16 cycles, with durations of 12 and 24 h, carbohydrate concentrations from 2.79 to 7.22 g L⁻¹, and applied volumetric organic loads from 2.6 to 12.6 g carbohydrate L⁻¹ day⁻¹. The best results were achieved with applied volumetric organic loads of 12.6 g carbohydrate L⁻¹ day⁻¹ and cycle length of 12 h, resulting in mean volumetric productivity of 0.88 L H₂ L⁻¹ day⁻¹, maximum molar flow of 10.80 mmol H₂ h⁻¹, and mean yield of 0.70 mol H₂ mol⁻¹ glucose consumed. The biogas H₂ content was between 18 and 42%, while the mean organic compounds removal and carbohydrate conversion efficiencies were 23 and 81%, respectively. The inoculum produced by natural fermentation was not viable.     

Optimal Designs of the Variable Sample Size Chart Based on Median Run Length and Expected Median Run Length

The variable sample size (VSS) chart, devoted to the detection of moderate mean shifts, has been widely investigated under the context of the average run‐length criterion. Because the shape of the run‐length distribution alters with the magnitude of the mean shifts, the average run length is a confusing measure, and the use of percentiles of the run‐length distribution is considered as more intuitive. This paper develops two optimal designs of the VSS chart, by minimizing (i) the median run length and (ii) the expected median run length for both deterministic and unknown shift sizes, respectively. The 5th and 95th percentiles are also provided in order to measure the variation in the run‐length distribution. Two VSS schemes are considered in this paper, that is, when the (i) small sample size (n_S) or (ii) large sample size (n_L) is predefined for the first subgroup (n₁). The Markov chain approach is adopted to evaluate the performance of these two VSS schemes. The comparative study reveals that improvements in the detection speed are found for these two VSS schemes without increasing the in‐control average sample size. For moderate to large mean shifts, the optimal VSS chart with n₁ = n_L significantly outperforms the optimal EWMA chart, while the former is comparable to the latter when n₁ = n_S. Copyright © 2016 John Wiley & Sons, Ltd.     

Application of variable‐structure system in dc‐motor velocity‐control

Abstract

The most important characteristic of variable‐structure system (VSS) is its insensitivity to parameter variations in the sliding mode. In this paper three methods of VSS are used to implement DC‐motor velocity‐control. The conventional VSS uses only a sliding line. The adaptive VSS uses multiple switching lines. The modern method uses a sliding curve. The modern method makes a system trajectory following the sliding curve which has been set up in the controller from the initial state to the origin in the phase plane. Hence it is insensitive to parameter variations from the initial state to the steady state. If parameter variations are the most critical factors, then the modern VSS is the right method to be considered to overcome the problem of parameter variations.     

UOP 工艺在3.5 Mt/a 催化裂化装置的应用

国内第一套设计加工能力达3.5 Mt/a 的大型重油催化裂化装置,采用美国 UOP 工艺技术设计.主要引进设备包括优混喷嘴,VSS 密闭旋分系统,高效汽提挡板等.运用开工汽油和分馏塔充瓦斯技术,减少催化剂跑损和富气不放火炬.运行情况显示:原料油雾化效果好、催化剂和油气分离效率高,采用国产 LDO-75催化剂及 ZSM-5助剂,装置有很好的重油转化和抗重金属能力,汽油收率32.25%,柴油收率32.26%,转化率44.18%,总液收82.01%.