Optimal controller tuning for nonlinear processes

The present work proposes a systematic methodology for the optimal selection of controller parameters in the sense of minimizing a performance index, which is a quadratic function of the tracking error and the control effort. The performance index is calculated explicitly as an algebraic function of the controller parameters by solving Zubov's partial differential equation (PDE). Standard optimization techniques are then employed for the calculation of the optimal values of the controller parameters. The solution of Zubov's PDE is also used to estimate the closed-loop stability region for the chosen values of the controller parameters. The proposed approach is finally illustrated in a chemical reactor control problem.     

拟线性抛物偏微分方程的双极解

研究了拟线性抛物型方程ut=uxx-|u|^p-1u的前向自型解。通过构造半线性微分方程的径向解，证明了自型解的存在性和唯一性。     

Focus projection of the parabolic radon transform and multiple waves separator, elimination

1　ＩＮＴＲＯＤＵＣＴＩＯＮＯｎｃｏｍｍｏｎ ｍｉｄｐｏｉｎｔ (ＣＭＰ)ａｎｄｃｏｍｍｏｎ ｓｈｏｔｐｏｉｎｔ (ＣＳＰ)ｇａｔｈｅｒｓ,ｓｅｉｓｍｉｃｔｉｍｅ ｄｉｓｔａｎｃｅｃｕｒｖｅｉｎ (ｘ,ｔ)ｄｏｍａｉｎｃａｎｂｅａｐｐｒｏｘｉｍａｔｅｄａｓｈｙｐｅｒｂｏ     

抛物方程的一种边界积分方程及其解的唯一性

本文给出二阶线性抛物型方程的边界积分方程,并证明了该边界积分方程的解的唯一性.     

一类退缩抛物型方程的广义解的C~(1·α)局部正则性

设Ω(?)R~N(N≥2)是一个有界区域,考虑方程:在适当的条件下,本文运用迭代法和一些技巧获得这个方程的广义解的C~(1·α)正则性。     

一类多维拟线性抛物型方程解的blow—up

本文用凸性方法研究了一类多维拟线性抛物型方程: 具有两类边界条件的混合问题解的blow—up性质,得到了其解必在有限时间内blow—u的充分条件。     

平底抛物线形无喉段量水槽试验研究

本文通过三种文丘利槽的初步研究，推荐其中适合曲线形渠道测流的平底抛物线形无喉段量水槽，与传统文丘利槽相比，它具有显著优点：１过流能力强，低水位测流精度高；２方便泥沙及漂浮物通过；３结构简单，呈良好流线形，工程量小；４具有较高的临界淹没度和可变的喉口断面收缩比。文中考虑喉口控制断面动水压力分布特征并根据喉口面积收缩比的概念，推导出槽前水深与流量计算公式：通过在Ｕ型渠道上的室内外试验和计算机仿真，给出     

Identifying a control function in parabolic partial differential equations from overspecified boundary data

Determination of an unknown time-dependent function in parabolic partial differential equations, plays a very important role in many branches of science and engineering. In the current investigation, the Adomian decomposition method is used for finding a control parameter p(t) in the quasilinear parabolic equation u_t=u_xx+p(t)u+, in [0,1]×(0,T] with known initial and boundary conditions and subject to an additional condition in the form of which is called the boundary integral overspecification. The main approach is to change this inverse problem to a direct problem and then solve the resulting equation using the well known Adomian decomposition method. The decomposition procedure of Adomian provides the solution in a rapidly convergent series where the series may lead to the solution in a closed form. Furthermore due to the rapid convergence of Adomian’s method, a truncation of the series solution with sufficiently large number of implemented components can be considered as an accurate approximation of the exact solution. This method provides a reliable algorithm that requires less work if compared with the traditional techniques. Some illustrative examples are presented to show the efficiency of the presented method.     

Moving parabolic approximation of point clouds

Using moving parabolic approximations (MPA), we reconstruct an improved point-based model of curve or surface represented as an unorganized point cloud, while also estimating the differential properties of the underlying smooth manifold. We present optimization algorithms to solve these MPA models, and examples which show that our reconstructions of the curve or surface, and estimates of the normals and curvature information, are accurate for precise point clouds and robust in the presence of noise.     

爆震频率对脉冲爆震发动机性能影响的试验研究

从影响脉冲爆震发动机爆震频率的因素出发,采用汽油为燃料,空气为氧化剂,研究了爆震频率对脉冲爆震发动机性能的影响。试验测取了各个爆震频率下稳定爆震的化学当量比范围,同时测试了不同工况下的爆震波压力、推力及爆震波速,发现当爆震频率较低时,发动机的工作范围较宽,爆震波压力、波速接近充分发展的理想爆震波,说明已产生了稳定、充分发展的爆震,脉冲爆震发动机的平均推力随着爆震频率的提高接近线性增大;但是随着爆震频率的提高,它的稳定工作范围变窄,爆震的强度降低。