基于用户授权的安全移动存储模型研究

目前针对移动存储设备的信息安全防护需求非常迫切,防止移动设备中的隐秘信息泄露问题尤其突出。本文采用WindowsNT内核操作系统的驱动框架,基于文件系统过滤驱动技术对移动存储设备中的数据进行透明加/解密,同时加入用户参与授权应用程序可信性的机制来进一步提高移动存储设备的安全性。     

大时滞系统时间协调参数调整控制策略

针对大时滞系统难以实现闭环稳定控制的问题,引入脉冲响应等效系统的概念,提出时间协调参数修改控制算法.该算法由两部分组成.一是通过时间协调原则修改控制器的输出;二是利用脉冲响应等效系统来修改控制器的参数,使脉冲响应等效系统和大时滞系统匹配,跟踪被控制对象参数变化产生自适应性,保证控制系统精度和稳定性.并用于氧化铝生产过程碳酸化分解工序,将原来手动操作开环控制改为闭环控制,提高了分解率和产品的合格率.该控制算法是递推算法,计算量小,便于在线实现.     

粗糙集理论在选矿生产成本分析中的应用

科学地分析影响原料消耗成本变化的主要因素,才能揭示成本变动原因,为成本控制提供有效依据.因此,提出基于粗糙集理论的原料消耗成本影响因素重要度确定方法.利用分类质量来度量各因素对原料消耗成本的影响程度,应用基于可辨识矩阵和逻辑运算方法求解决策表的最小简约,找出影响原料消耗成本的确定性因素和不确定性因素,为改进生产提供辅助决策支持.实例分析表明,该方法简捷实用,可定量分析影响因素对原料消耗成本的影响程度.     

Chinese-based research on subject-covered information retrieval supervised by textual semantic domain

By means of analysis of artificial intervention in ready-retrieved text, training set used to compare with new texts from large-scale real texts corpus is provided. It is based on the data-originated presentation of training set that a special formula to calculate semantic cohesion between new texts and training set is devised. The semantic cohesion of new text is the average value of semantic evaluation of all elements involved, and semantic evaluation of an element depends on its semantic relevance with the training set and on the semantic ratio of its domain to synonymous domain. In terms of empirical verification a conclusion is drawn that semantic cohesion is the key measurement standard of textual retrieval. Despite the advantages of textual retrieval, limitations of formula-raised condition and analyst＇s accomplishments make the analysis involved in this paper imperfect.     

试析中西方绘画形式异同之思想根源

中国人在绘画艺术上走的道路与西方绘画不同,究其思想根源在于中国文化中的艺术精神。一方面是孔孟儒家所显现的"中和之美"的典型;另一方面是由老庄道家所显现出来的彻底的纯艺术精神的性格。中国艺术家在儒道思想的影响下,致力于自身与天道的融合,西方的画家则是在希腊文化和基督教文明人文主义思想的光环中完成自己理想的嬗变。     

基于DSP的电源控制系统的软硬件开发

介绍了一种基于DSP的逆变电源控制系统,详细阐述了系统组成结构和软硬件设计.该系统采用TMS320F2812作为主控制器,最大程度的减少了硬件电路的搭建,实现了对逆变电源的数字控制.实验结果证明,该系统具有良好的稳压功能,既能满足一定控制精度要求,又能满足实时性要求,可以很好的控制115V/400Hz逆变电源的输出.     

Dual-band reflective polarization converter based on metasurface

In this paper, a dual-band and reflective polarization converter based on metasurface is proposed. Its unit cell is composed of two layers of metal plates separated by a dielectric substrate. The simulation results show that the proposed converter is able to convert x- or y-polarized incident waves into cross-polarized waves perfectly in frequency bands of 6.75—10.59 GHz and 17.78—19.61 GHz, and the polarization conversion ratio (PCR) is nearly 100%, which can also convert linearly polarized waves into circularly polarized waves at four frequencies. It can be widely used in applications of radar satellites, antenna design and telecommunication with the function of realizing polarization conversion in two bands and achieving high PCR simultaneously.