查询词典 iteration method

Through theoretical derivation, the author proved that the Landweber method is the transmogrification of the iteration solution of the generalized inverse, so the phenomenon that the reconstructed images of Landweber through many iterative processes is close to those reconstructed by generalized inverse method is explained, then a new reconstruction algorithm, namely pre-iteration method is presented, which divides the process of reconstruction into two steps, namely off-line pre-iteration and on-line one-step reconstruction.

通过理论推导，作者证明了Landweber法实际上可归于广义逆矩阵迭代求解的变形，从而解释了Landweber法多次迭代后，趋于广义逆解的现象。

Simultaneously, the exports of ionization rate and nonionzed concentration are set up as a powerful tool for studying thoroughly the freeze-out effect. dN〓/dp and dN〓/dn are neglected in the linearized equation system of the iteration methods of Newton and Gummel, due to having lower 15 orders or more than dN〓/dn and dN〓/dp, thus the computing effort is cut down with no effect on precision. A new cut-off technique is adopted to accelerate the convergence speed, about twice reduced for Newton iteration method and six times or so for Gummel iteration method. The approximate formulae of Fermi-Dirac statistics are also put forward with simpler form and higher precision. 3. A term dependent on time is added to the electron and hole current succession equations respectively. It is only this model that conservation of charge in transient analysis and alternating small-signal analysis at low temperature can be kept by. 4. The performance of SE-PISCES is explained by the simulation example of PISCES-2B, diode.

研究了低温半导体器件模拟的数值方法：对载流子浓度进行了新的归一化；编制了不考虑掺杂所引进的内建电场时的电离率计算程序；由于低温杂质电离率随偏压状态而变化，为此编制了每次求解迭代时的电离浓度计算程序，并将其插入到求解迭代程序中；同时，设置了杂质电离率和未电离杂质浓度的出口点，为更深入地研究冻析效应提供了有力工具；在Newton迭代法和Gummel迭代法的线性化方程组中忽略了dN〓/dp、dN〓/dn，是因为它们比dN〓/dn、dN〓/dp低15个数量级以上，这样减小了计算量又不影响模拟精度；对Newton迭代法和Gummel迭代法采取了新的截断技术，提高了收敛速度，Newton法迭代法和两次左右，Gummel法减少六次左右；给出了表达式更简单而精度更高的Fermi-Dirac积分近似计算公式。

And iteration, iteration and Jacobi iteration is compared part too.

论文的第三部分，用一个例题来进行说明。

And iteration, iteration and Jacobi iteration is compared part too.

同时将 迭代法、超松弛迭代法与之比较。

Main points of the thesis are as follows:(1) The main function models and information relations between these models in the CAPP system in the integrated CAD/CAM project are explained, a new process plan design method is mentioned based on analyses of process plan design. This method is based on the process plan prototype, and develops the prototype little by little until the perfect process plan is completed, the prospect of this method is discussed;(2) The feature abstracting rules and methods are studied, a feature coding system is developed based on GT, all the defined feature models are described by the mathematical methods;(3) The integrated method of CAD/CAPP based on features is mentioned, this method defines a feature exchanging model, and develops an interface software to exchange design data into technology data base, this technology data base includes the design and technology information of the parts;(4) The process plan reasoning method based on features is created, this method uses Mycin algorithm to solve the reasoning of the feature process plan. A process plan making system is developed. In this system part process plan is made by the semi-intelligent method, this method uses the feature reasoning, feature process chain searching and man-computer talking together;(5) The main structure of the HOPE system is introduced, a shaft drawing and its process plan made by this system are shown, the data process problem in process drawing making is also discussed;(6) A new method of describing process rule is introduced, this method uses IfThen rules and neural nets weight values together to describe process rules, the BP algorithm is adopted in this method;(7) The optimal machining sequence problem of the process steps on the same fixturing is discussed, optimal algorithms SA is applied to solve this problem, the result shows that this method is more efficient than the traditional method;(8) All jobs in the thesis are summarized. In order to carry out the research in the future, some rational proposals are given.

全文论述的内容主要有下列几个方面：(1)较为系统地阐述了CAD／CAM一体化工程项目中CAPP系统的主要功能模块及其信息流程，在分析工艺设计过程的基础上，提出了基于特征原型的渐进式工艺设计方法，并探讨了该方法的应用前景；(2)研究了零件特征提取的原则和方法，在成组技术的基础上，开发了一套基于特征的分类编码系统，并在提取零件特征的基础上，定义了零件特征的数据模型，开发了基于轴类零件特征的参数化设计系统；(3)研究了基于特征的CAD／CAPP集成的方法，通过定义零件特征数据模型的存储结构，开发了将设计数据转换到工艺数据库中的接口程序，为后续的CAPP系统提供必要的零件形状和工艺信息；(4)研究了基于特征的工艺推理方法，将Mycin算法应用到工艺决策中，开发了基于特征的工艺推理及工艺方案生成系统，在系统中综合运用特征推理、特征加工工艺链查询及人机对话相结合的半智能化方法确定零件加工工艺；(5)介绍了整个HOPE系统的总体结构，通过运行HOPE系统绘出了一轴类零件的零件图，并生成了该零件的加工工艺方案，初步探讨了基于特征的工序图生成技术中数据处理问题；(6)研究了工艺设计过程中知识如何有效表示的问题，提出了将显式的IF-THEN规则表示与隐式神经网络权值表示相结合的工艺知识表示方法，并利用BP算法进行了工艺知识表示的初步研究；(7)研究了工艺设计过程中同一安装下工步优化排序问题，利用神经网络中基于模拟退火的理论来解决该工步优化排序问题，实践证明该方法较传统的算法具有更高的效率；(8)总结了本文所进行的研究工作，为今后进一步开展工作提出了较为合理的建议。

In this paper Ⅰ successfully applied these methods to fault diagnosis, and presenting some new innovative machinery fault diagnosis method; First Ⅰ present a new gear wornout fault diagnosis method, this method use the vibration signal's time-frequency attribute and instantaneous phase undulation to accurately detect gear's fault, and by comparing with the traditional frequency domain analysis method, this method reveals that many nonlinear and nonstationary characteristic exist in gear's vibration, this tell us that if we use frequency domain analysis method without pay attention to the signal's characteristic, we could get wrong diagnostic result; Then Ⅰ present a new bearing fault diagnosis method, this method use ATVFD and Hilbert transform to do envelop demodulation,Ⅰ analyze the envelop with time-frequency method and find out that this method is more accurate then traditional method.Ⅰ also explain that the modulation of the fault to the carrier wave may also be non-stationary and nonlinear; Finally Ⅰ present a cylinder pressure measurement method of diesel engine by means of vibration, cylinder pressure is an important parameter of diesel engine fault diagnosis, the pressure measuring is simplified a lot by this method,Ⅰ also use the ATVFD and time-frequency analysis to realize it.

本文中将上述理论方法成功地应用到故障诊断中去，提出了几点创新性的诊断方法；提出了一种齿轮磨损故障诊断的新方法，该方法利用振动信号能量的时频域分布特征与瞬时相位波动特征可以进行精确的齿轮故障诊断，并通过与传统的频域诊断方法的比较，揭示出齿轮振动中存在的明显的非线性与非平稳特征，说明了不加选择地利用频域分析方法进行齿轮故障诊断很可能会得到错误的诊断结果；提出了一种轴承故障诊断的新方法，该方法利用ATVFD分解与Hilbert变换进行包络解调，并对解调得到的包络信号进行时频域分析，可以实现更加准确轴承故障诊断，说明了故障对载波信号的调制往往也是非平稳与非线性的；提出了一种利用振动信号进行柴油机汽缸内压力检测的新方法，柴油机汽缸压力的变化是柴油机故障诊断的重要参数，利用振动方法可大大简化汽缸压力的检测过程，该方法也是综合利用ATVFD分解与时频域分析方法实现的。

Firstly, the principle of the iteration method is presented, the characteristic of the method is analyzed. The downward continuation computation for model and practical data with noise of different variance is performed by means of iteration method.

首先介绍了迭代法的基本原理，分析迭代法的特点；然后利用迭代法对不同噪声水平的模型数据和实测数据进行向下延拓计算，研究噪声对迭代法的计算误差影响。

Based on prestressed steel beams, considering effect of the method of construction to slip and stress increment, accoding to conception that procedure of calculation reflects the procedure of construction and change of structural internal force, making good use of the method of section conversion and making iteration reflect the coupling of slip and stress increment, bringing forth a method of iteration and modified stiffness to calculate the deflection of prestressed composite steel-concrete beams in normal servicing prase.

以预应力钢梁为基础，充分考虑施工方法对结构滑移和应力增量的影响，依据设计计算中反映施工过程和结构受力变化过程，通过截面换算，以循环迭代法来考虑滑移和预应力钢束的耦合作用，提出了计算预应力钢—混凝土组合梁正常使用阶段挠度变形的迭代—修正刚度法。

In orderto improve the complex subspace iteration method for solving undamped gyroscopiceigenvalue problems, we apply the special properties of undamped gyroscopiceigenvalues to it, so we propose double inverse iteration method and double subspaceiteration method.

为了利用无阻尼陀螺特征值的特殊性质，我们进一步讨论了复子空间迭代法在无阻尼陀螺特征值问题中的应用，并给出了双逆迭代算法和双子空间迭代算法。

This dissertation gives the damping iteration method and geome-tric-mean tracing method, both based on inversion of observed ground-water level data, and also gives the proportional iteration (or ortho-gonalization) method based on inversion of hydrogeologic gradient data.

本文建立了用水位观测资料进行反演的阻尼迭代法和几何均值追踪法，利用水力梯度资料进行反演的比例迭代法。

Please name screenshots descriptively to avoid confusion.

请用描述性的文字为抓图命名，以避免混乱。

In Philadelphia, the United States of America was born and George Washington served as first President.

费城是美利坚合众国的诞生地，也是华盛顿担任第一任总统的地方。