基于约束优化问题的人工鱼群算法及其改进

在人工鱼群算法基础上,对人工鱼群算法进行改进,结合遗传算法提出的适应度函数来解决约束优化问题.具体表现在改进了人工鱼的觅食行为,另外引入了吞噬行为以便加快收敛速度,得到更优的适应度值.仿真结果表明改进的人工鱼群算法在解决约束优化问题时,具有收敛速度快、适应度值优、全局寻优性能强等优点.改进的人工鱼群算法较之基本人工鱼群算法具有更好的性能.     

Combined centralized and decentralized controlfor high precision spacecraft

The improved structural filter combined with Positive Position Feedback(PPF) controller is investigated for high-precision attitude control of flexible spacecraft which consists of rigid central body a...     

Enhancing pose accuracy of space robot by improved differential evolution

Due to the intense vibration during launching and rigorous orbital temperature environment, the kinematic parameters of space robot may be largely deviated from their nominal parameters. The disparity will cause the real pose (including position and orientation) of the end effector not to match the desired one, and further hinder the space robot from performing the scheduled mission. To improve pose accuracy of space robot, a new self-calibration method using the distance measurement provided by a laser-ranger fixed on the end-effector is proposed. A distance-measurement model of the space robot is built according to the distance from the starting point of the laser beam to the intersection point at the declining plane. Based on the model, the cost function about the pose error is derived. The kinematic calibration is transferred to a non-linear system optimization problem, which is solved by the improved differential evolution (DE) algorithm. A six-degree of freedom (6-DOF) robot is used as a practical simulation example, and the simulation results show: 1) A significant improvement of pose accuracy of space robot can be obtained by distance measurement only; 2) Search efficiency is increased by improved DE; 3) More calibration configurations may make calibration results better.     

基于激光雷达和摄像机的前方车辆检测

考虑到激光雷达和机器视觉间信息的互补性,提出了一种融合图像和雷达信息的前方目标车辆检测方法.分析激光雷达数据的特点,提出了改进的基于密度的空间聚类算法实现雷达数据的聚类.目标车辆检测时,首先通过信息融合确定车辆的初始检测区域,生成车辆假设;然后利用模糊推理系统融合车辆多个特征验证车辆假设,实现车辆检测.试验结果表明,算法实现了无约束条件下的目标车辆检测,并且具有较好的适应能力和抗干扰能力,能准确地检测前方目标车辆.     

改进人工鱼群优化粗糙集的水电机组故障诊断

针对水电机组大量的现场监测数据信息,基于传统的人工智能方法对故障信息不能及时有效地分析的问题,提出了一种基于改进人工鱼群优化粗糙集的水电机组故障诊断方法．首先,利用鱼群的寻优聚群行为对连续属性进行离散化,然后采用粗糙集理论对离散化后的决策表进行约简,建立故障诊断规则决策表,再用提取的规则对水电机组故障进行诊断．仿真结果表明：与传统方法相比,该算法能够提高水电机组故障诊断的准确率．     

AES改进算法在CCMP协议中的应用

AES针对IEEE 802.11i中CCMP所采用的高级加密标准AES算法的实现较为复杂且对硬件要求较高的情况,对AES算法进行了优化改进.首先对列变换进行了优化,并基于系数的正交化统一了算法加解密过程的运算; 然后对轮变换过程进行了简化,并将优化后的列变换系数应用于其中进一步简化了轮变换过程.将本文的改进算法与原AES算法和S -AES算法进行对比表明,本文算法在不降低算法本身安全性的前提下,减小了其实现代价,提高了算法的效率.     

固体聚合硫酸铁生产工艺改进探究

探究酸性条件下,以硫酸亚铁晶体为原料,以双氧水为氧化剂直接氧化法生产固体聚合硫酸铁的最佳工艺条件.并应用于指导实际生产,生产出低能耗、高絮凝效果、运输方便、环境友好型的絮凝剂.     

Optimized Hemolysin Type 1 Secretion System in Escherichia coli by Directed Evolution of the Hly Enhancer Fragment and Including a Terminator Region

Type 1 secretion systems (T1SS) have a relatively simple architecture compared to other classes of secretion systems and therefore, are attractive to be optimized by protein engineering. Here, we report a KnowVolution campaign for the hemolysin (Hly) enhancer fragment, an untranslated region upstream of the hlyA gene, of the hemolysin T1SS of Escherichia coli to enhance its secretion efficiency. The best performing variant of the Hly enhancer fragment contained five nucleotide mutations at five positions (A30U, A36U, A54G, A81U, and A116U) resulted in a 2-fold increase in the secretion level of a model lipase fused to the secretion carrier HlyA1. Computational analysis suggested that altered affinity to the generated enhancer fragment towards the S1 ribosomal protein contributes to the enhanced secretion levels. Furthermore, we demonstrate that involving a native terminator region along with the generated Hly enhancer fragment increased the secretion levels of the Hly system up to 5-fold.     

分子筛辅助人参须根粉快速制备人参皂苷Rg5的工艺研究

利用多功能改进型索氏提取器为提取工具,以人参须根粉为原料,盐酸为催化剂,分子筛辅助下高效制备了稀有人参皂苷Rg5,并通过单因素实验优化了工艺条件。实验结果表明：当以30 mL的甲醇为溶剂、加入0.3 g 4 A分子筛、于65 ℃提取4 h时,人参总皂苷的提取率达到10.2%,稀有人参皂苷Rg5的得率达到3.20%,与传统索氏提取器相比可以显著提高人参皂苷Rg5的制备效率。分子筛辅助下利用多功能改进型索氏提取器从人参须根粉提取制备稀有人参皂苷Rg5,不仅得率较高,而且操作简单快捷,是一种快速制备人参皂苷Rg5的工艺方法。     

振荡翼改进运动模型的能量捕获性能分析

为了提高振荡水翼的水动力性能和能量捕获效率,基于传统简谐运动模型提出改进运动模型,通过引入俯仰运动系数k,推导改进后俯仰运动规律的一般形式,利用Fluent软件建立水翼的二维模型,综合分析半主动振荡模型下不同俯仰运动系数、折算频率和俯仰振幅等运动参数对水翼能量捕获性能的影响。结果表明:与传统简谐运动模型相比,改进运动模型能够使水翼升力系数在较长时间段内维持较大数值,提高水翼的升力系数和捕能效率;在相同的折算频率和俯仰振幅下,减小俯仰运动系数会增大俯仰角转动的角速度,进而增大俯仰运动所消耗的能量;不同俯仰振幅下对应不同的最优折算频率,折算频率越低水翼的捕能性能越不稳定,俯仰振幅越大,转动俯仰角所消耗的能量越多。在给定参数条件下,水翼的能量转化效率可超过40%。