关键词： genetic algorithm   aeroelastic instability   flutter   distributed computing  

摘要： In this paper, a process by which experimental, or historical, data are used to create physically meaningful mathematical models is demonstrated. The procedure involves optimising the correlation between this 'real world' data and the mathematical models using a genetic algorithm which is constrained to operate within the physics of the system. This concept is demonstrated here by creating a structural dynamic finite element model for a complete F/A-18 aircraft based on experimental data collected by shaking the aircraft when it is on the ground. The processes used for this problem are easily broken up and solved on a large number of PCs. A technique is described here by which such distributed computing can be carried out using desktop PCs within the secure computing environment of the Defence Science & Technology Organisation without compromising the PC or network security.

关键词： acclimatization chamber   condition-sequence control   Boolean algebra   psychrometrics   programmable logical controller  

摘要： The objective of this paper was to link a psychometric chart and Boolean algebra algorithms on deducing the procedural and logical issues of temperature-humidity environmental control for a grafted seedling acclimatization chamber. We developed a condition-sequence control circuit based on Boolean algebra algorithms to solve the complex logical problem existing in temperature-humidity environmental control procedures. A Matlab program was used to deduce and simplify the Boolean relations between input and output logical variables of the controller, whereas the correctness of Boolean function was verified by an Excel program. The Boolean functions were firstly transformed to switching (logical) circuits and subsequently transformed to a programmable logical controller (PLC) program systematically. We implemented the developed industrial wiring devices and PLC in designing a temperature-humidity environmental controller of an acclimatization chamber for grafted seedlings in that we adopted the nonlinear control technique associated with the condition-sequence control methodology as the main control scheme. On the other hand, we adopted the compound control action, two-position set point action, the time-delay control and the conditional action of free cooling as the main control operations for the controller. Our results demonstrate that the overall seasonal survival rate was 97% by using the Boolean algebra-based controlled chamber grafting, which was higher than that of 90% by employing the field grafted seedling operations. (c) 2005 Elsevier B.V. All rights reserved.

关键词： 燃气管网   水力计算   数学建模   管网结构  

摘要： 本文在总结前人成果的基础上,首先应用图论的方法分析管网的结构,用矩阵的方法描述管网的各个属性间的关系;其次通过分析水力计算的公式找到管网属性的描述方式;最后是进行了计算程序的编制,并应用编制的计算程序,对三种不同工作状态下的燃气管网进行的试算,结果满足了各项管网属性及精度的要求.利用此计算程序可以合理地选取燃气管网的管径;可以从管网结构不同的几个方案中选取水力工况优的方案;可以模拟管网系统中可能出现的事故时管网中各节点的压力和流量的变化,从而合理增大供气系数,并预估管网系统改造对整个系统的影响.

关键词： 自相关   信号检测   白噪声   数学形态学   最小二乘递推算法   仿真结果   扰动   在线   精确定位   算子  

摘要： 提出了一种基于短窗自相关算法和数学形态学的电能质量扰动信号检测和定位新方法。该方法能够滤除电流、电压信号中的白噪声,易于在线实现。作者先利用最小二乘递推算法估计信号的基本成分,以提取信号中的扰动成分和白噪声的混合信息;再利用短窗自相关算法滤除混合信息中的随机噪声以提取扰动信息;最后利用数学形态学的基本腐蚀算子检测扰动并进行精确定位。仿真结果表明了该方法的有效性。

关键词： 弱目标   遥感图像   数学形态学  

摘要： 从弱目标图像(空间遥感图像)的复杂背景中提取弱小目标一直是一个重要而复杂的课题。遥感图像具有灰度变化丰富,所含信息量较大,背景噪声复杂的特点。针对以上问题,文章讨论了在低对比度、强干扰的情况下,对弱目标的提取方法。采用基于数学形态学理论的方法来对遥感图像中的弱目标进行检测处理,提出了一种从遥感图像中提取具有一定外形的弱小目标,并可以在实际系统上实现的算法。给出在具典型意义的SAR图像上的实验分析和实验模拟处理结果,验证了这种算法在强噪声和复杂背景下的有效性。也证明了该算法具有理论完备、算法简单、抗噪能力强和运算速度较快的优点。

关键词： nonlinear programming   complementarity problems   contact problems   finite elements   structural optimization  

摘要： We discuss a special mathematical programming problem with equilibrium constraints (MPEC), that arises in material and shape optimization problems involving the contact of a rod ora plate with a rigid obstacle. This MPEC can be reduced to a nonlinear programming problem with independent variables and some dependent variables implicity defined by the solution of a mixed linear complementarity problem (MLCP). A projected-gradient algorithm including a complementarity method is proposed to solve this optimization problem. Several numerical examples are reported to illustrate the efficiency of this methodology in practice.

关键词： 中学数学   渗透   数学课程标准   逻辑思维能力   普通高中   必修内容   算法思想   基本思想   表达能力   信息时代   必然趋势   数学发展   教育部  

关键词： 加密算法   RSA算法   数据加密   数字签名   算法设计  

摘要： 我在学习加密算法RSA算法的过程遇到了一些数学问题,资料上所讲的也不是很清楚,这里我想用简单明了有程序语言将其RSA算法表达出来,并将有些地方给予证明,希望对大家有所帮助.

关键词： 图像融合   模糊数学   统计信号处理   EM算法  

摘要： 针对多传感器图像在像素级上的融合问题,将模糊数学理论引入到图像融合模型。该模型假定理想的融合后的图像包含场景所有的信息;将它乘上一个模糊因子,再加上随机噪声,可用来描述某一个成像传感器中获得的场景图像;不同的传感器对应不同的模糊因子和噪声。在此基础上,提出了建立在非多尺度分解框架下的图像融合算法。它以各传感器获取的图像作为输入条件,应用统计信号处理中的EM算法,求出针对不同传感器的噪声参数和模糊因子,通过迭代估计出融合的图像。实验结果显示,该算法获得的融合图像的互信息和联合熵分别达到3.5079和24.732,均优于加权平均融合法、小波融合算法和Laplacian融合算法的融合质量。

关键词： 图像处理   边缘检测   数学形态学  

摘要： 基于数学形态学的方法,利用形态运算膨胀、腐蚀、开、闭等变换以及它们的组合,该文提出了一种改进的形态学边缘检测算子,能够有效地检测出图像边缘,并保持边缘的平滑性.同时引入多尺度的概念,对形态结构元素尺度的大小进行调整,从而在噪声存在的条件下得到较理想的图像边缘.实验结果表明,与传统的边缘检测算子相比较,该算法抗噪性能良好,计算量较小,因此具有一定的实用性和可行性.