Study of probability integration method parameter inversion by the genetic algorithm

In order to obtain accurate probability integration method(PIM) parameters for surface movement of multi-panel mining, a genetic algorithm(GA) was used to optimize the parameters. As the measured surface movement is affected by more than one mining panel, traditional PIM parameter inversion model is difficult to ensure the reliability of the results due to the complexity of rock movement. With crossover,mutation and selection operators, GA can perform a global optimization search and has high computation efficiency. Compared with the pattern search algorithm, the fitness function can avoid falling into local minima traps. GA reduces the risk of local minima traps which improves the accuracy and reliability with the mutation mechanism. Application at Xuehu colliery shows that GA can be used to inverse the PIM parameters for multi-panel surface movement observation, and reliable results can be obtained. The research provides a new way for back-analysis of PIM parameters for mining subsidence under complex conditions.     

Φ159mm限动芯棒连轧管机组限动速度的确定

芯棒是限动芯棒连轧管机组的主要变形工具之一,限动速度的合理设定有助于减小芯棒磨损,提高产品质量,降低生产成本。采用MPM连轧数模及德国Meer公司的二级控制方法,可推算出与芯棒限动速度有关的参数,再根据生产实际予以修正,可以得到最佳参数。介绍了鞍钢集团新钢铁有限责任公司合理确定限动芯棒连轧管机组芯棒限动速度的方法。     

一类自适应预测控制方法及在电液比例控制中的应用

为电液比例系统提供了一个输入输出增量式线性时变模型，采用加权限定记忆回归法来估计模型参数，在此基础上进而提出了一种自适应预测控制方法，并给出了最优控制律，仿真结果表明了该线性时变模型和参数估计算法的可行性，表明该自适应预测控制方法具有优良的控制品质。     

基于参数化特征建模的汽车转向器CAD系统的研制

通过对汽车转向器结构特点进行分析，得出了汽车转向器CAD策略，利用UG软件平台并结合UG／OpenGRIP语言来创建参数直接驱动的转向器三维参数化CAD建模程序，开发了一种基于参数化特征建模的汽车转向器CAD系统。经实际应用表明，该系统设计效率高，实用性强，大大缩短了产品开发周期。     

模态分析技术及其在锻压工程中的应用前景

本文介绍了模态分析技术的概念、目的、内容和方法,论述了模态分析技术在锻压工程中的应用前景,以及它在建立锻压机械动态设计理论中的作用。     

装饰用梅花形黄铜管拉伸成型工艺研究

通过对梅花形黄铜管一次拉伸成型的实验 ,研究了管坯的规格、管坯的状态、延伸系数、拉伸方式、工艺润滑及拉伸速度等工艺因素对梅花黄铜管凸筋高度充填的影响规律 ,这些结论对实际生产有一定的指导意义。     

基于双EnKF的土壤水分与土壤属性参数同时估计

为提高土壤水分数据同化结果的精度,将基于双集合卡尔曼滤波(Dual Ensemble Kalman Filter,DEnKF)的状态-参数估计方案与简单生物圈模型(simple biosphere model 2,SiB2)相结合,同时更新土壤水分和优化模型参数(土壤属性参数)。选用2008年6月1日~10月29日黑河上游阿柔冻融观测站为参考站,开展了同化表层土壤水分观测数据的实验。研究结果表明:DEnKF可同时优化土壤属性参数和改进土壤水分估计,该方法对表层土壤水分估计的精度0.04高于EnKF算法的精度0.05。当观测数据稀少时,DEnKF算法仍然可以得到较高精度的土壤水分估计,3层土壤水分的估计精度在0.02~0.05之间。     

Optimal design of adaptive type-2 neuro-fuzzy systems: A review

Type-2 fuzzy logic systems have extensively been applied to various engineering problems, e.g. identification, prediction, control, pattern recognition, etc. in the past two decades, and the results were promising especially in the presence of significant uncertainties in the system. In the design of type-2 fuzzy logic systems, the early applications were realized in a way that both the antecedent and consequent parameters were chosen by the designer with perhaps some inputs from some experts. Since 2000s, a huge number of papers have been published which are based on the adaptation of the parameters of type-2 fuzzy logic systems using the training data either online or offline. Consequently, the major challenge was to design these systems in an optimal way in terms of their optimal structure and their corresponding optimal parameter update rules. In this review, the state of the art of the three major classes of optimization methods are investigated: derivative-based (computational approaches), derivative-free (heuristic methods) and hybrid methods which are the fusion of both the derivative-free and derivative-based methods.     

A multi-criteria trajectory-based parameter sampling strategy for the screening method of elementary effects

Environmental models are inherently complex and often characterized by high dimensionality. The method of elementary effects (EE) is one of the most widely used parameter screening technique implemented to reduce burden on computational resources required for thorough model evaluation. Due to issues like inefficient screening and excessive sampling time, the development of more effective EE sampling strategies has been a recent research focus. This paper presents a new sampling strategy - Sampling for Uniformity (SU) – based on the principles of meeting close-to-theoretical parameter distributions and maximizing trajectory spread. The performance of the SU relative to existing strategies was evaluated using a number of criteria including generated parameter distributions' uniformity, time efficiency, trajectory spread, and screening efficiency. The SU performed better than some trajectory-based benchmark strategies across the evaluation criteria, underlining the effectiveness of multi-criteria based sampling and the need to focus future efforts on exploring other combinations of sampling criteria.