基于广义随机Petri网的鱼雷系统级测试性参数确定方法

在装备论证阶段,提出科学合理的测试性指标要求,可以有效指导测试性设计。目前鱼雷武器系统还缺乏有效的测试性参数定量分析方法,在综合比较现有各种测试性需求分析模型的基础上,提出了一种基于广义随机Petri网的测试性建模方法。通过构建鱼雷武器系统基层级维修保障流程的广义随机Petri网模型,得到状态可达图,并利用同构法,求解了测试性参数与可用度之间的关系;以可用度和平均故障修复时间为设计指标,对国外某型鱼雷的测试性参数进行了求解,并利用Petri网 建模工具PIPE4.3.0软件进行了仿真分析,验证了模型和算法的有效性。     

基于CiteSpace的食品和肠道微生物研究的计量分析

本文以Web of Science（WOS）核心文集为数据来源,运用CiteSpace软件对2004~2022年食品和肠道微生物研究领域的8310篇相关文献的年度发文量、作者、国家和机构合作网络、关键词共现和突现以及文献共被引图谱进行分析。结果表明:自2005年来,食品和肠道微生物领域的年发文量逐年增长;该领域的主要研究主题是饮食对肠道微生物和相关疾病的影响;目前该领域的研究前沿为乳化剂、共生、肠道微生物、嗜黏蛋白阿克曼菌和开菲尔等;我国在该领域的发文量位居第二,但国际合作较少,后续应扩展国际合作,进一步提高相关研究水平。     

超高压处理对变温结晶制备糯米慢消化淀粉的影响

以糯米粉(蛋白质量分数为7.97％)和糯米淀粉(蛋白质量分数为0.58％)为研究对象,利用超高压(100、300、500 MPa)结合变温结晶(4℃和25℃间隔24 h循环条件下放置1、3、7 d)的方式制备慢消化淀粉,通过测定样品的慢消化淀粉质量分数并进行热力学性质、糊化特性和傅里叶变换红外光谱分析,研究超高压处理对...     

Theoretical investigation of anisotropic mechanical and thermal properties of ABO3 (A=Sr,Ba; B=Ti,Zr, Hf) perovskites

As promising TBC (thermal barrier coating) candidates, perovskite oxides own designable properties for their various options of cations and structural diversity, but limited comprehensions of structure‐property relationship delay their engineering applications. In this work, mechanical/thermal properties of ABO₃ (A=Sr, Ba; B=Ti, Zr, Hf) perovskites and their anisotropic nature are predicted employing density functional theory. Their theoretical minimum thermal conductivities range from 1.09 to 1.74 W·m^?1·K^?1, being lower than Y₂O₃ partially stabilized ZrO₂. Reduced thermal conductivities up to 16% along particular directions are reached after considering thermal conductivity anisotropy. All compounds own high hardness while SrZrO₃, SrHfO₃, and BaHfO₃ possess well damage tolerance. We found that small electronegativity discrepancy leads to big anisotropy of chemical bond, Young's/shear moduli and thermal conductivities, together with good damage tolerance. These results suggest that the next generation TBCs with extra low thermal conductivity should be achieved through combining material design and orientation‐growth tailoring.     

Automated cell classification and visualization for analyzing remyelination therapy

Remyelination therapy is a state-of-the-art technique for treating spinal cord injury (SCI). Demyelination—the loss of myelin sheath that insulates axons, is a prominent feature in many neurological disorders resulting in SCI. This lost myelin sheath can be replaced by remyelination. In this paper, we propose an algorithm for efficient automated cell classification and visualization to analyze the progress of remyelination therapy in SCI. Our method takes as input the images of the cells and outputs a density map of the therapeutically important oligodendrocyte-remyelinated axons (OR-axons) which is used for efficacy analysis of the therapy. Our method starts with detecting cell boundaries using a robust, shape-independent algorithm based on iso-contour analysis of the image at progressively increasing intensity levels. The detected boundaries of spatially clustered cells are then separated using the Delaunay triangulation based contour separation method. Finally, the OR-axons are identified and a density map is generated for efficacy analysis of the therapy. Our efficient automated cell classification and visualization of remyelination analysis significantly reduces error due to human subjectivity. We validate the accuracy of our results by extensive cross-verification by the domain experts.     

基于粗糙集理论的电子镇流器故障诊断方法

将粗糙集理论引入电子镇流器的故障诊断,提出了一种基于粗糙集理论的电子镇流器故障诊断方法.通过对论域进行降维,大大降低了计算复杂性.在此基础上通过属性约简和值约简,导出了有用的诊断决策规则.实例分析表明,将粗糙集理论应用于镇流器故障诊断,可得到清晰、简明的诊断规则,提高了故障诊断的能力,对进行在线质量控制具有实际应用价值.     

Implementation and test results of a wide-area measurement-based controller for damping interarea oscillations considering signal-transmission delay

The paper describes the implementation of a centralised control-design scheme in a real-time laboratory-based dynamic simulator. A centralised multivariable-control algorithm is designed employing remote feedback signals considering delay in signal transmission. The transmitted signals can be used for multiple-swing-mode damping using a single controller. Such an algorithm is numerically intensive owing to the high controller size and the predictor that takes care of the delay in signal transmission. The performance of the proposed controller is demonstrated by practical implementation using a rapid-prototyping controller mounted on a PC-ATX. Results of the experimental tests are shown for a detailed model of the power system implemented using Linux PC-based multiprocessor technology.     

An adaptive color image steganography method using adjacent pixel value differencing and LSB substitution technique

Abstract

Steganography is a data-concealing technique that provides a covert communication. This paper proposes a spatial domain color steganography method that uses a neighboring pixel-pair differencing concept to enhance the embedding capacity. The proposed method considers the distortion tolerance capacity of each color plane and the difference value between two neighboring pixels while deciding the number of bits that can be concealed in that pixel-pair. Each plane is divided into some disjoint blocks of size 3?×?3 pixels. The method forms eight pairs of pixels in one block using the eight-neighboring pixel concept, which enables the method to utilize all the edge pixels in all probable directions. It also uses the XOR encoding technique before the embedding process. This step provides an additional layer of security to the secret information. The simulation results show that the proposed method is able to achieve a high embedding capacity with good visual quality as per the calculation of imperceptibility metrics. The robustness of the method is tested by RS steganalysis and pixel difference histogram analysis. Further, a comparison between the proposed method and the existing methods on the basis of embedding capacity and stego image quality is shown.