利用调和映射的复杂网格曲面螺旋刀轨生成算法

针对截平面法规划的复杂网格曲面刀轨的加工效率不高问题,提出一种复杂网格曲面螺旋刀轨生成算法.首先采用调和映射的方法对网格曲面进行参数化,然后根据残留高度确定参数网格中的参数环,在相邻参数环的参数点之间进行“分组匹配”,并依次计算初始和精确的对角参数螺旋线;在此基础上采用“区域划分”的方法快速生成了无干涉的网格曲面螺旋刀轨.对于复杂网格曲面的实验结果表明,文中的螺旋刀轨能够有效地提高截平面法刀轨的加工效率,且能够保证较好的加工质量.     

独立学院大学计算机基础课程教学的几点思考

针对当前独立学院大学计算机基础课程教学中面临的一些问题,结合教学实践,提出了分层教学模式,以期更好地为独立学院培养计算机技能上手快,后劲足的应用型人才:对不同层次的对象采取不同的教学内容和方式;面向专业,将计算机基础教学内容模块化,结合专业划分必修与选修模块,在内容深度和广度上更好地为专业服务;教学内容面向实用,兼顾体系,突出重点,精讲精练.     

观测永久丢失下随机离散事件系统故障预测的验证算法

针对随机离散事件系统在故障预测时可能出现系统观测永久丢失,导致预测不准确的问题,提出一种观测永久丢失下故障预测验证的算法。首先对观测永久丢失的随机离散事件系统的U-可预测性进行了形式化。其次使用随机预测器构造了一个随机离散事件系统的U-预测器,实现了系统的故障预测。基于U-预测器,提出了随机离散事件系统U-可预测性的充分必要条件及验证算法,并且引入成对的方式,明显地改进了该验证算法的复杂度。仿真结果表明,该验证算法使得观测永久丢失下系统故障预测准确。最后,实例说明观测永久丢失下故障预测验证算法的应用。结果表明,该验证算法相比现有同类验证算法应用范围更广,验证结果更精确。     

Application of genetic algorithm-based intuitionistic fuzzy weighted c-ordered-means algorithm to cluster analysis

Knowledge and Information Systems - With the advance of information technology, many fields have begun using data clustering to reveal data structures and obtain useful information. Most of the...     

基于PetaLinux的块设备驱动程序设计

本文介绍了一款针对MicroBlaze软核处理器特别开发的嵌入式操作系统PetaLinux,研究了该操作系统中自定义外围设备驱动程序的开发过程,完成了自定义块设备驱动程序的发布,并成功地实现了其在PetaLinux操作系统内核中的编译与加载,为大容量数据块的传输提供了可行的方案.     

校园网络立体化数据存储方案的研究与设计

本文针对校园网络数据存储方式单一、成本高、实用性不高的问题,设计了一个实用、可操作性的立体化数据存储方案。该方案发挥raid、虚拟存储和数据容灾三种存储技术各自的优势,将这三种存储技术有机的融合,构建了三个存储层,物理存储层、虚拟存储层、数据容灾备份层,每个层又采取两种不同的存储方式,在实用、低廉的基础上实现数据的安全冗余和立体化备份,从而确保校园应用数据的安全性和可用性。     

Optimal Performance in Tracking Stochastic Signal Under Disturbance Rejection

The analysis method of optimal tracking performance is proposed for multiple‐input multiple‐output (MIMO) linear time‐invariant (LTI) systems under disturbance rejection. An H₂ criterion of the error signal between the output of the plant and the reference signal is used as a measure for the tracking performance. Spectral factorization is applied to obtain the optimal solution of the system tracking error. The explicit expressions are derived for this minimal tracking error with respect to random reference signals under disturbance rejection. It is shown that the nonminimum phase zeros, the zero direction, the unstable poles, the pole direction of a given plant, statistical characteristics of the reference input signal, and disturbance signal have a negative effect on a feedback system's ability to reduce the system error with disturbance rejection. The results show that the optimal tracking performance will further be damaged because of disturbance rejection. Some typical examples are given to illustrate the theoretical results.     

基于数字媒体技术的图像融合算法

图像融合技术是数字媒体技术中很重要的一个方向。图像融合因为其融合后可以保留相对较多的场景,融合后图像精度高,便于后续图像中目标观测和特征点的提取。研究一种基于数字媒体技术的图像融合算法,并与其它传统的图像融合算法进行了比较。     

Resveratrol Butyrate Esters Inhibit BPA-Induced Liver Damage in Male Offspring Rats by Modulating Antioxidant Capacity and Gut Microbiota

Resveratrol can affect the physiology or biochemistry of offspring in the maternal–fetal animal model. However, it exhibits low bioavailability in humans and animals. Fifteen-week SD pregnant female rats were orally administered bisphenol A (BPA) and/or resveratrol butyrate ester (RBE), and the male offspring rats (n = 4–8 per group) were evaluated. The results show that RBE treatment (BPA + R30) compared with the BPA group can reduce the damage caused by BPA (p < 0.05). RBE enhanced the expression of selected genes and induced extramedullary hematopoiesis and mononuclear cell infiltration. RBE increased the abundance of S24-7 and Adlercreutzia in the intestines of the male offspring rats, as well as the concentrations of short-chain fatty acids (SCFAs) in the feces. RBE also increased the antioxidant capacity of the liver by inducing Nrf2, promoting the expression of HO-1, SOD, and CAT. It also increased the concentration of intestinal SCFAs, enhancing the barrier formed by intestinal cells, thereby preventing BPA-induced metabolic disruption in the male offspring rats, and reduced liver inflammation. This study identified a potential mechanism underlying the protective effects of RBE against the liver damage caused by BPA exposure during the peri-pregnancy period, and the influence of the gut microbiota on the gut–liver axis in the offspring.