共查询到20条相似文献,搜索用时 671 毫秒
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研究了基于遗传算法和差分进化计算的入侵检测系统中的特征选择技术,差分进化计算在变异过程中并未考虑到适应度大的个体,同时存在过早收敛问题,而遗传算法需要很多的迭代次数才能收敛.针对以上缺点,结合模拟退火算法对差分进化的变异过程进行改进,同时设计合理的适应度函数,使得该算法收敛于最优特征子集.经过Lincoln实验室入侵检测系统评估数据集合MIT' 1998测试,改进算法与差分进化算法和遗传算法相比,具有良好的收敛性能,并且收敛特性稳定. 相似文献
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对HIGHT进行了差分故障攻击.攻击采用单字节级的差分故障模型,在倒数第3轮和倒数第4轮进行故障诱导来恢复密钥.模拟实验结果显示采用大约32次故障诱导便可恢复密钥,分析的计算复杂度约为256.模加差分表预计算的复杂度为232. 相似文献
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本文提出一种基于DNA存储、RNA转录模型下的密钥识别管理方法,传输机制采用量子通信机制,模型构想为采用密钥胞、密钥核构造结构机理存储密钥。密钥识别基于分子识别原理,利用分子接触时会产生分子间力的作用模型抽象成信息传递、信号接触后产生识别作用力来验证信源身份,进而产生密钥胞内部反应机制,将存储在密钥核的密钥序转录成密钥传送到密钥胞发送口,再传递给通过身份验证的信源。 相似文献
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自生长密钥,是指随着使用过程,密钥的长度不断生长,对明文进行加密的密钥不断变化.通过多螺旋运算,通讯双方各自独立按需持续生成密钥,在双方约定的整个生命周期中,每一个数据包加密的密钥都是新生成的,每轮密钥包括2568=18,446,744,073,709,551,616个密钥切片,每个密钥切片为16字节,基于密钥生成逻辑的概率计算,出现重复密钥轮大概需要25616=3.4028236692093846346337460743177e+38轮,按此计算,基于本算法,有效密钥的长度将达到16 * 2568* 25616=1.0043e+59(地球的原子数量大约为1.0e+50),通过源头暴力破解需要进行25648=2384=3.9402e+115次尝试才能够找到. 相似文献
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DES加密算法的密钥扩展 总被引:1,自引:0,他引:1
介绍了DES加密算法及其安全性,指出目前存在的几种主要的攻击方法.提出了一种利用密钥生成非线性的置换表的方法,大大增加了密钥长度.在不改变原有算法主体结构的基础上,增强了算法的安全性尤其是抗穷密钥搜索攻击和抗差分密码分析能力. 相似文献
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实践中,有的企业故意不参加企业年检,在被吊销营业执照后又不依法清算,借被吊销营业执照来逃避债务,这种状况极大的扰乱了市场经济的正常秩序.本文通过一案例来深入分析企业法人被吊销营业执照的清算责任及其诉讼地位的确定. 相似文献
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<正>在电子设备上PowerPC与可拆卸存储设备互联的硬件构型下,本文提出合理的加载数据的加解密方法。该方法的核心是密钥分布式存储。通过密钥管理机使用一级密钥加密随机二级密钥得到三级密钥。使用二级密钥加密加载数据。通过网络将加载的数据,三级密钥均分布在可拆卸存储设备上不同分区。PowerPc通过读取加密的数据、三级密钥,使用一级密钥及对称解密算法对加密的三级密钥进行解密得到二级密钥,再使用二级密钥对加载的数据进行解密。使用的加解密算法为256位的AES。 相似文献
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This study measured the speed, error rates, and subjective evaluation of arrow-jump keys, a jump-mouse, number keys, and a touch screen in an interactive encyclopedia. A summary of previous studies comparing selection devices and strategies is presented to provide the background for this study. We found the touch screen to be the fastest in time, the least accurate but the overall favorite of the participants. The results are discussed and improvements are suggested accordingly. 相似文献
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Christopher W. Gregory Katelyn L. Sellgren Kristin H. Gilchrist Sonia Grego 《Biomicrofluidics》2013,7(5)
A versatile method to fabricate a multilayer polydimethylsiloxane (PDMS) device with micropillar arrays within the inner layer is reported. The method includes an inexpensive but repeatable approach for PDMS lamination at high compressive force to achieve high yield of pillar molding and transfer to a temporary carrier. The process also enables micropillar-containing thin films to be used as the inner layer of PDMS devices integrated with polymer membranes. A microfluidic cell culture device was demonstrated which included multiple vertically stacked flow channels and a pillar array serving as a cage for a collagen hydrogel. The functionality of the multilayer device was demonstrated by culturing collagen-embedded fibroblasts under interstitial flow through the three-dimensional scaffold. The fabrication methods described in this paper can find applications in a variety of devices, particularly for organ-on-chip applications. 相似文献
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本文主要以单片机STC89C516为核心,分别连接了防盗装置、火焰报警装置和煤气报警装置集成于一体的设计。电路由信号输入,按键、指示和报警,单片机基本电路,信号测试、远端通信四部分组成。本设计增加一种防盗电路,特别适用于家庭。 相似文献
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Integration of nano-materials in optical microfluidic devices facilitates the realization of miniaturized analytical systems with enhanced sensing abilities for biological and chemical substances. In this work, a novel method of integration of gold nano-islands in a silica-on-silicon-polydimethylsiloxane microfluidic device is reported. The device works based on the nano-enhanced evanescence technique achieved by interacting the evanescent tail of propagating wave with the gold nano-islands integrated on the core of the waveguide resulting in the modification of the propagating UV-visible spectrum. The biosensing ability of the device is investigated by finite-difference time-domain simulation with a simplified model of the device. The performance of the proposed device is demonstrated for the detection of recombinant growth hormone based on antibody-antigen interaction. 相似文献
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GaN材料在光电子和微电子领域中得到广泛的应用,因此它是第三代半导体材料的典型代表。它具有宽的直接带隙、强的原子键、高的热导率、化学稳定性好(几乎不被任何酸腐蚀)等性质和强的抗辐照能力,在光电子、高温大功率器件和高频微波器件应用方面有着广阔的前景。在成像技术方面,GaN类的成像器件包括紫外摄像机和紫外数字照相机。 相似文献
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The recent development of microfluidic "lab on a chip" devices requiring sample sizes <100 μL has given rise to the need to concentrate dilute samples and trap analytes, especially for surface-based detection techniques. We demonstrate a particle collection device capable of concentrating micron-sized particles in a predetermined area by combining AC electroosmosis (ACEO) and dielectrophoresis (DEP). The planar asymmetric electrode pattern uses ACEO pumping to induce equal, quadrilateral flow directed towards a stagnant region in the center of the device. A number of system parameters affecting particle collection efficiency were investigated including electrode and gap width, chamber height, applied potential and frequency, and number of repeating electrode pairs and electrode geometry. The robustness of the on-chip collection design was evaluated against varying electrolyte concentrations, particle types, and particle sizes. These devices are amenable to integration with a variety of detection techniques such as optical evanescent waveguide sensing. 相似文献
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In this work, we demonstrate the use of a thin, self adherent, and clinically durable patch device that can collect fluid from a wound site for analysis. This device is manufactured from laminated silicone layers using a novel all-silicone double-molding process. In vitro studies for flow and delivery were followed by a clinical demonstration for exudate collection efficiency from a clinically presented partial thickness burn. The demonstrated utility of this device lends itself for use as a research implement used to clinically sample wound exudate for analysis. This device can serve as a platform for future integration of wearable technology into wound monitoring and care. The demonstrated fabrication method can be used for devices requiring thin membrane construction. 相似文献
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Microfluidic paper-based analytical devices (μPADs) are widely used for performing diagnostic assays. However, in many assays, time-delay valves are required to improve the sensitivity and specificity of the results. Accordingly, this study presents a simple, low-cost method for realizing time-delay valves using a color wax printing process. In the proposed approach, the time-delay effect is controlled through a careful selection of both the color and the saturation of the wax content. The validity of the proposed method is demonstrated by performing nitrite and oxalate assays using both a simple two-dimensional μPAD and a three-dimensional μPAD incorporating a colored wax-printed timer. The experimental results confirm that the flow time can be controlled through an appropriate selection of the color and the wax content. In addition, it is shown that nitrite and oxalate assays can be performed simultaneously on a single device. In general, the results presented in this study show that the proposed μPADs provide a feasible low-cost alternative to conventional methods for performing diagnostic assays. 相似文献
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针对目前电子产品元器件贴装工艺高度普及、表面安装器件SMD大量被使用的现状,通过对表面安装器件SMD的介绍,分别研究了SMD分立器件、SMD集成电路以及大规模集成电路的贴装方式,对各种贴装方式加以比较,提出最佳贴装工艺方案。 相似文献
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Gang Li Yahui Luo Qiang Chen Lingying Liao Jianlong Zhao 《Biomicrofluidics》2012,6(1):014118-014118-16
This paper presents an easy-to-use, power-free, and modular pump for portable microfluidic applications. The pump module is a degassed particle desorption polydimethylsiloxane (PDMS) slab with an integrated mesh-shaped chamber, which can be attached on the outlet port of microfluidic device to absorb the air in the microfluidic system and then to create a negative pressure for driving fluid. Different from the existing monolithic degassed PDMS pumps that are generally restricted to limited pumping capacity and are only compatible with PDMS-based microfluidic devices, this pump can offer various possible configures of pumping power by varying the geometries of the pump or by combining different pump modules and can also be employed in any material microfluidic devices. The key advantage of this pump is that its operation only requires the user to place the degassed PDMS slab on the outlet ports of microfluidic devices. To help design pumps with a suitable pumping performance, the effect of pump module geometry on its pumping capacity is also investigated. The results indicate that the performance of the degassed PDMS pump is strongly dependent on the surface area of the pump chamber, the exposure area and the volume of the PDMS pump slab. In addition, the initial volume of air in the closed microfluidic system and the cross-linking degree of PDMS also affect the performance of the degassed PDMS pump. Finally, we demonstrated the utility of this modular pumping method by applying it to a glass-based microfluidic device and a PDMS-based protein crystallization microfluidic device. 相似文献