An interval-valued hesitant fuzzy multigranulation rough set over two universes model for steam turbine fault diagnosis

In the field of mechanical engineering, steam turbine fault diagnosis is a difficult task for mechanical engineers who are confronted with challenges in dealing with copious amounts of uncertain information. Different mechanical engineers may have their own opinions about the system fault knowledge base that differs slightly from other mechanical engineers. Thus, to solve the problems presented by uncertain data analysis and group decision-making in steam turbine fault diagnosis, we propose a new rough set model that combines interval-valued hesitant fuzzy sets with multigranulation rough sets over two universes, called an interval-valued hesitant fuzzy multigranulation rough set over two universes. In the multigranulation framework, both basic definitions and some important properties of the proposed model are presented. Then, we develop a general approach to steam turbine fault diagnosis by using the proposed model. Lastly, an illustrative example is provided to verify the established approach and demonstrate its validity and applicability.     

一种基于动态模糊综合评判的故障预测新方法

针对影响装备寿命的许多故障因素和故障关系具有复杂性、非确定性以及时变性的特点，指出了传统模糊综合评判方法的不足，提出了基于动态模糊综合评判的故障预测方法，给出了动态权重矩阵和动态隶属度的确定方法，以火炮反后坐装置为例对评判过程予以说明，证明了该方法的有效性和实用性。并将模糊综合评判与产生式规则相融合，利用复合推理机制提高预测结果的准确性。     

Wall-following of mobile robot based on fuzzy genetic algorithm to linear interpolating

Traditional fuzzy controller has some disadvantages, such as inferiorly adaptability due to the invariable membership function parameters and too many subjective factors. So in this paper, we firstly put forward a new method to fuzzy inference based on the idea of linear interpolating. This method overcomes the shortcoming of conventional fuzzy controller such as the character of multi-relay and the conflict of rule numbers and real-time. Then we use genetic algorithm to off-line optimize the membership function parameters of fuzzy controller, which is used in the controlling course of mobile robot following straight wall. The result shows the optimizing control strategy is more effective in the aspect of following precision than the traditional fuzzy controller.     

小卫星在轨故障诊断的模糊神经网络模型

小卫星高性能，高自主的发展趋势对于在轨故障诊断技术的实现要求日益迫切，而受小卫星体积小，重量轻，能源少的限制，当前常用的建立在高性能计算机硬件基础上的各种诊断方法不再适用于强调实时性，准确性的在轨运行监测，诊断与恢复和重构重处理。本文小卫星一体化系统总体设计技术研究与集成化设计系统为基础，采用一种神经网络与模糊系统相结合的模糊神经网络（ＦＮＮ）模型来分区域表示诊断系统并基于该ＦＮＮ模型进行诊断推量     

基于故障诊断专家数据库系统的模糊模式识别

本文分析了模糊逻辑方法进行诊断的不足,提出了基于广义贴近度的模糊模式识别方法,建立并讨论了相应的故障诊断专家数据库系统     

基于插值机理的分布参数系统T-S模糊推理建模

研究分布参数系统的建模问题,给出一种基于T-S模糊推理与HX方法的T-S型模糊三角插值推理建模方法,满足插值机理.理论分析表明方法可利用有限的采样数据推断分布参数系统的时空变化规律.仿真实验显示方法是有效的,且具有建模精度较高的特点.     

单水箱液位控制系统的模糊推理建模及仿真

首先,依据实际背景,利用单水箱实验系统设计了几种典型的液位控制实验;然后,将模糊推理建模法应用于实际的单水箱液位控制系统中,推导得到其数学模型,即变系数线性微分方程组;最后,利用仿真实验检验了这些数学模型的准确性。结果表明这种建模方法比较精确,充分考虑了实际系统的非线性特性。     

A soft computing-based approach to spatio-temporal prediction

This paper aims to incorporate intelligent mechanisms based on Soft Computing in Geographical Information Systems (GIS). The proposal here is to present a spatio-temporal prediction method of forestry evolution for a sequence of binary images by means of fuzzy inference systems (FIS), genetic algorithm (GA) and genetic programming (GP). The main inference is based on a fuzzy system which processes a set of crisp/fuzzy relations and infers a crisp relation representing the predicted image at a predefined date. The fuzzy system is formed by a fixed fuzzy rule base and a partition set that may be defined by an expert or optimized by means of a GA. Genetic programming may also be adopted to generate the size of predicted area used in the final stage of the inference process. The developed methodology is applied in regions of Venezuela, France and Guatemala to identify their forestry evolution trends. The proposed approaches are compared with other techniques to validate the system.     

故障诊断中模糊神经网络的应用研究

文章给出了利用模糊神经网络诊断故障的数学模型、基本原理、方法、步骤 ,和模糊网络的学习流程 ,并利用梯度法推导出两种诊断算法 ;在对某发动机滑油典型故障样本的仿真过程中 ,结果完全正确 ,对非样本故障的仿真 ,准确率达 90 % .     

基于Matlab灰色神经网络的电力变压器故障诊断研究

针对电力变压器故障的特点及传统诊断方法在变压器故障诊断中的局限性,提出了基于灰色神经网络的变压器故障诊断方法.首先将典型油中气体浓度样本集作为参考序列,挖掘出样本集中的故障信息,然后利用灰色神经网络进行变压器的故障诊断.通过大量的实例,并将诊断结果与IEC三比值法和改良三比值法的诊断结果相比较,表明基于matlab灰色神经网络的诊断方法具有更高的精确度.     

A general fuzzy control scheme for nonlinear processes with stability analysis

In this paper we develop a general fuzzy control scheme for nonlinear processes. Assuming little knowledge about the dynamics of the controlled process, the proposed scheme starts by probing the process at different points in its operating region to generate a fuzzy quantisation. A simple local controller is then designed at each fuzzy locality. A fuzzy inference mechanism then links up tje local controllers to form a global controller which can be further refined by the learning algorithm. By employing a newly developed structure-adaptive fuzzy modelling scheme, the appropriate fuzzy rule-base for the inference mechanism can be extracted stably and efficiently. The conditions for the stability of the global controller are rigourously established. Simulation results are presented to illustrate the effectiveness of the scheme.     

基于GA-PLS和AdaBoost的故障诊断方法

提出一种基于GA-PLS和AdaBoost的液压系统故障诊断方法。该方法用遗传算法与偏最小二乘法相结合(Genetic algorithm-partial least squares,GA-PLS)的算法对初始特征向量进行筛选,提取出与故障信息相关程度高的特征向量,把该特征向量作为输入,运用AdaBoost(Adaptive Boost)方法建立分类器,以识别液压系统的工作状态和故障类型。对实验数据分析的结果说明,该方法能准确地选择出特征向量,并有效地应用于液压系统的故障诊断。     

A route-choosing medical diagnostic technique

The central component of an expert system for medical diagnosis is presented. Its context is described, as is its inference technique with special reference to (a) the use of fuzzy logic, (b) a route-choosing heuristic technique to reduce the cost of reaching a diagnosis and (c) the tree-structuring of the domain which follows clinicians' division into syndromes.     

Filtering-based robust fault detection of fuzzy jump systems

This paper studies the robust fault detection filter (RFDF) design problems for uncertain nonlinear Markov jump systems with state delays and parameter uncertainties. By means of Takagi-Sugeno fuzzy models, the dynamics of filtering error generator and the fuzzy RFDF system are constructed. With the aid of the selected weighting matrix function, the design objective is to find an optimal RFDF which results in a minimal difference between the reference model (ideal solution) and the RFDF (real solution) to be designed. A sufficient condition is firstly established on the stochastic stability by using stochastic Lyapunov-Krasovskii functional approach. Then in terms of linear matrix inequalities techniques, sufficient conditions on the existence of fuzzy RFDF are presented and proved. Finally, the design problem is formulated as an optimization algorithm. Simulation results illustrate that the proposed RFDF can detect the faults shortly after the occurrences.     

A fuzzy inverse relation based on godelian logic and its applications

Fuzzy logic applicable to decision-making processes such as diagnostic expert systems and fuzzy controllers is the prime concern of this paper. In these applications, an inverse operation (or backward inference) plays an important role. In the current paper, a new backward inference technique based on Gödelian logic is proposed. The relation between the forward and backward inferences is established by introducing fuzzy joint and conditional relations.     

About premise reduction of fuzzy inference algorithm

The comprehensive model with “weighted-objective nearness degree” is introduced in the process of multi-objective decision-making, by which a reduction problem of inference antecedents is studied in traditional fuzzy inference method. Moreover, based on the comprehensive model with “weighted-objective nearness degree”, SMTT fuzzy inference algorithm is proposed. This algorithm not only shows the relative importance of every antecedent component in fuzzy inference, but also considers the influence of nearness degree between every antecedent component’s evaluation and inference objective on inference conclusions. The enactment of inference objective reflects the preference degree of decision maker to every antecedent component’s evaluation. Therefore, it is much fitter for the demands of practical inference.     

概率因果模型结合改进遗传算法的核动力系统故障分析

将概率因果模型的似然函数作为遗传算法的适应函数,从而将复杂系统的故障诊断转化为最优问题,建立了一种将概率因果模型和遗传算法相结合的故障诊断方法,并利用改进算法与概率因果故障诊断模型对船用核动力装置进行故障诊断实例分析,分析结果对船用核动力装置故障诊断具有重要的指导意义,而改进遗传算法是进行船用核动力装置故障诊断有效而实用的方法。     

Reasoning under uncertainty with FIR methodology

The aim of this research is to develop a new methodology called UNFIR (uncertainty in FIR) as an extension of the fuzzy inductive reasoning (FIR) technique. The main idea behind UNFIR is to expand the modeling capacity of the FIR methodology allowing it to work with classical fuzzy rules. On the one hand, UNFIR is able to automatically construct fuzzy rules starting from a set of pattern rules obtained by FIR. On the other hand, UNFIR affords the prediction of systems behavior by using a mixed pattern/fuzzy inference system that takes advantage of the uncertainty inherent to the data. The pattern rule base that the FIR methodology generates can be very large, obstructing the prediction process and reducing its efficiency. The new methodology preserves as much as possible the knowledge of the pattern rules in a compact fuzzy rule base. In this process some precision is lost but the robustness is considerably increased.The performance of UNFIR methodology as a systems’ prediction tool is also studied in this work. Three different applications are used for this purpose, i.e., a linear system, a non-linear system and an industrial process.     

Symmetric implicational method of fuzzy reasoning

Fuzzy reasoning should take into account the factors of both the logic system and the reasoning model, thus a new fuzzy reasoning method called the symmetric implicational method is proposed, which contains the full implication inference method as its particular case. The previous full implication inference principles are improved, and unified forms of the new method are respectively established for FMP (fuzzy modus ponens) and FMT (fuzzy modus tollens) to let different fuzzy implications be used under the same way. Furthermore, reversibility properties of the new method are analyzed from some conditions that many fuzzy implications satisfy, and it is found that its reversibility properties seem fine. Lastly, the more general α-symmetric implicational method is put forward, and its unified forms are achieved.     

具有模糊属性的关联产生式发掘算法及应用

本文通过不确定性推理的分析，提出了模糊关联的概念，用模糊概念表示事务数据之间的关联关系，研究了模糊关联的性质，给出了模糊关联产生式的发掘算法及应用的实例．