基于改进证据理论的故障诊断方法研究及应用

针对传感器证据信息全局修正针对性不强及冲突证据无法判别等问题,提出基于改进证据理论的故障诊断方法。利用冲突证据判据判断可信证据与冲突证据,保留可信证据,通过可信度对冲突证据进行针对性修正。该判断及局部修正可降低传感器证据信息的不确定性,并减弱冲突信息对合成结果影响。结合神经网络建立特征空间到证据空间的映射,有效利用网络输出结果,通过信息熵构建原始证据。将所有证据用改进D-S公式合成。通过齿轮泵早期故障试验,与神经网络及其它证据合成方法对比表明,该方法诊断精度较高,从而验证了融合方法的有效性。     

基于SVM-DS证据理论融合决策的故障诊断方法

针对复杂工况下单传感器对于装备故障诊断识别率低、证据缺乏、数据冗余等问题,提出一种基于支持向量机(Support Vector Machine,SVM)结合D-S证据理论的多维度特征数据融合决策故障诊断方法。首先,通过多种方法提取特征构建SVM分类器,对故障类型进行初步分类;然后,将Sigmoid函数作为传递函数,利用SVM分类器对测试数据进行分类,获取测试样本的后验概率并得到测试样本的混淆矩阵;最后,根据混淆矩阵求出局部可信度与全局可信度,并与后验概率相结合实现基本概率分配函数赋值,通过融合计算得到最终诊断结果。实验结果表明,融合后的分类器模型对内圈故障类型分类准确率达100%,对正常和滚珠类型分类准确率为95%,对外圈故障分类准确率为90%。采取多特征融合诊断相较于单一方法有较高准确率和鲁棒性,可有效降低单一特征提取所带来的不稳定性。     

基于证据理论的产品包装方案综合成本测度

目的研究不确定信息背景下产品包装方案的综合成本测度,实现产品包装方案的优选。方法对产品包装方案综合成本测度指标体系进行层次化建模;采用隶属度的方法对测度指标的初始评分值进行规范化处理,引入权重来实现对各测度指标重要程度的区分;将备选包装方案视为辨识框架中的焦元,计算各测度指标下所有焦元的加权基本概率分配值,并进行两阶的Dempster合成,最后基于信任区间进行备选包装方案综合成本的测度。结果通过某小型电气控制柜包装方案综合成本测度的案例应用,识别出最优的包装方案,验证了所提出方法的有效性和可行性。结论所提出方法能够为专家评分含有不确定信息时的产品包装方案综合成本测度提供了一种解决思路。     

产品总体方案评价与优选的证据推理决策

产品总体方案评价与优选决策是产品设计过程中的重要步骤,它是决定总体设计之后进行详细设计的关键环节。考虑产品总体方案评价与选择决策过程中不确定、不完全主观判断的混合多属性决策问题,提出基于证据推理的决策模型;对决策属性中定量属性的证据处理以及不同定性属性不同辨识框下的情况进行了讨论。最后给出了实例。     

基于粗糙集的证据合成方法

提出一种基于粗糙集的证据合成方法,有效的解决证据理论在信息融合中组合证据无权重的问题,并对此方法在人脸识别中的应用做分析。     

基于D-S证据理论和AHP的故障诊断方法研究

提出了一种基于D-S证据理论和AHP的故障诊断方法，给出了基于AHP法的基本概率分配构造方法．最后，结合故障诊断实例，详细阐述了该诊断方法的应用过程，在对多个传感器提供的证据进行合成后，诊断结论的可信度明显提高，不确定性明显降低，证明该诊断方法合理有效．     

基于D-S证据理论信息融合的转辙机故障诊断方法研究

在列车提速后S700K型电动转辙机被普遍安装在正线道岔的背景下,本文针对单一故障诊断方法的诊断精度偏低问题,提出了基于信息融合故障诊断模型和故障诊断方法.该方法分别用BP神经网络和模糊综合评判对转辙机进行故障诊断,利用神经网络输出和模糊综合评判输出来构造D-S证据理论中的概率分配,然后利用D-S证据理论将BP神经网络和模糊综合评判对转辙机的故障诊断结果在决策级进行融合,诊断转辙机是否有故障并判断故障的模式.诊断结果表明,该诊断方法具有较高的故障诊断精度,诊断结论的可信度有明显提高.     

一种基于D-S证据理论的复杂产品模块划分评价方法

模块划分是复杂产品模块化设计的基础,划分的优劣直接关系到客户定制产品设计、制造和装配的效率。针对现有的研究在模块划分方案形成以后缺乏对模块优劣的合理评价,该文通过引入D-S证据理论,从装配复杂性、可制造性、模块性、稳定性、造型结果与体积紧凑性6个指标对模块创建方案的满意度进行不确定和不完全性的综合评判,提出了一种双层模块化创建方案评价方法。该方法符合人的思维判断过程,具有一定的灵活性、有效性和合理性。     

基于证据理论的断路器机械故障诊断方法

研究了证据理论在高压断路器故障诊断中的应用。探讨了D-S证据理论的有效性问题,并在失效性情况下提供了一种证据理论的改进方法以解决D—S算法在实现过程中存在的证据冲突问题。通过仿真实验,对该方法的有效性进行了验证。     

基于集合属性和优先度的D-S证据决策方法

为了降低利用D-S证据组合结果进行决策的风险,提出了一种基于集合属性和优先度的证据决策方法,将决策问题分解成精细信度区间的构造和比较两个层面.在构造层面引入集合的不确定性测度和焦元间属性支持度,获取基元命题的精细信度区间值;在比较层面引入优先度评价各命题的精细信度区间,然后在优先度排序的基础上构建了证据决策模型.该方法的特点在于以区间值作为决策依据,充分利用了信度区间所蕴含的信息.实验分析结果表明,该方法是合理、有效的,克服了其它单点值D-S证据决策方法所存在的误决策或不做决策的问题.     

Group-based product scheme-screening decision method based on fuzzy AHP and evidential reasoning theory

Selecting the favourable product scheme is the first step to successful new product development (NPD). There are usually large numbers of uncertainties in product scheme evaluation and screening process of NPD due to lack of or incomplete reliable information. Considering fully the uncertainties and then conducting correct reasoning could guarantee reliability and rationality of scheme-screening results. As an extension of analytic hierarchy process (AHP), fuzzy AHP inherits multi-merits of the AHP approach and is capable of dealing with fuzzy information effectively, but it still has two weaknesses. One is the well-known ranking reversal problem. Although several researchers have analysed the reasons, we think the root cause for ranking reversal problem is due to the fact that AHP treats weights of attribute criteria and performance scores of alternatives in the same way. Therefore, we intend to deal with attribute weights and performance scores of alternatives separately and introduce evidential reasoning (ER) theory, which is good at uncertain reasoning, into fuzzy AHP to calculate the performance scores of alternatives. On the other hand, in view of the difficulty in resolution for fuzzy weights from fuzzy comparison matrix, a linear goal-programming model is proposed to calculate fuzzy weights, whose objective is to minimise the inconsistency degree of comparison matrix. By combining fuzzy AHP with ER, a group-based hybrid decision model FAHP-ER is developed. The hybrid model not only gets a great improvement in the capability of dealing with uncertainty, but also reflects the most real decision scenario and thinking process of the decision maker. Finally, a case study for schemes screening of the rotor and bearing system in the turbine generator is presented to demonstrate the application of the hybrid decision method.     

基于案例的文化创意产品设计方法研究

针对文化产品的造型设计,将与产品造型相关的设计元素细分为功能、行为、文化、情感和构造法五个方面,结合基于案例的设计(case-based design,CBD)技术、遗传算法以及形状文法知识,建立文化创意产品设计概念原型系统并对文化创意产品进行引导设计。提出产品造型相关设计元素多目标优化模型,对用户需求进行匹配操作。提出文化产品造型设计方法模型,结合产品基因树交叉操作与形状文法知识,将现代类产品与文化器物类产品的设计元素进行交叉重组。通过对产品造型相关设计元素进行深入研究,并在文化创意产品设计概念原型系统中融入基于案例的设计技术、遗传算法和形状文法的知识,辅助设计师对文化产品进行创意设计。以小音箱为例,验证了该方法的可行性,为文化产品设计提供了一种有效方法。     

Enhanced reliability analysis method for multistate systems with epistemic uncertainty based on evidential network

Evidential network is considered to have superiority in conducting reliability analysis for complex engineering systems with epistemic uncertainty. However, existing methods tend to result in combinational explosion when multistate systems are involved in the reliability analysis, which means the reliability analysis cost increases exponentially with the number of components and that of functioning states. Therefore, an enhanced reliability analysis method is proposed in this paper for reliability analysis and performance evaluation of multistate systems with epistemic uncertainty, through which the combination explosion can be significantly alleviated. Firstly, the functioning states of each component are sequenced according to utility functions. Secondly, the basic belief assignment (BBA) of each component is reassigned in terms of commonality function, through which the BBA defined in the power set space is represented by two extreme BBA distributions defined in the frame of discernment. Thirdly, the reliability intervals of the system states are calculated through evidential network, and the system performance level is computed. Two multistate system numerical examples are investigated to demonstrate the effectiveness and efficiency of the proposed method.     

基于突变理论的机械产品突破性创新耗散结构模型及其评价

为揭示机械产品突破性创新内在的动态演化机制,提出了一种基于突变理论的机械产品突破性创新耗散结构模型及其评价方法.首先叙述了耗散结构理论与熵变;然后应用发明问题解决理论(TRIZ)中的冲突解决原理分析了机械产品突破性创新尖点突变过程,建立了机械产品突破性创新耗散结构模型,指出了机械产品是在一个非平衡的开放系统中,系统内各技术子系统之间非线性相互作用下,以尖点突变的形式产生的宏观的“巨涨落”,从而形成的一种新的有序的耗散结构;最后基于信息熵理论提出了机械产品突破性创新的评价方法.以中药滴丸机为例,对2种不同状态下的滴丸机进行定量分析,结果较好地验证了该方法的合理性.     

Decision theory classification of high-dimensional vectors based on small samples

In this paper, an entirely new procedure for the classification of high-dimensional vectors on the basis of a few training samples is described. The proposed method is based on the Bayesian paradigm and provides posterior probabilities that a new vector belongs to each of the classes, therefore it adapts naturally to any number of classes. The classification technique is based on a small vector which can be viewed as a regression of the new observation onto the space spanned by the training samples, which is similar to Support Vector Machine classification paradigm. This is achieved by employing matrix-variate distributions in classification, which is an entirely new idea.      

以TRIZ进化理论为基础的产品技术预测支持系统研究

产品技术预测是使企业保持长久竞争优势的有效方法之一,而TRIZ的技术进化理论恰恰是众多产品技术预测理论中最具优势和生命力的。以TRIZ的技术进化理论为基础,运用先进的计算机软件编程技术--基于Windows2000环境, 以Visual Basic 6.0为开发语言,Access作为后台数据库,采用DAO数据库访问技术,构建了基于TRIZ进化理论的产品技术预测支持系统。该系统由8个模块组成,分别是系统维护、待预测产品数据库、产品技术成熟度预测、技术进化路线分析、技术进化知识库、工程报表、编辑和学习帮助模块,通过系统的应用可以实现产品技术成熟度的预测分析,为产品提供可能的技术进化模式或进化路线,将以前手工完成的工作软件化,从而使企业快速、准确地把握产品的技术走向,实现产品和技术的创新。     

Improving product based on affordance with fuzzy theory for product development strategy

This paper presents a design strategy which combines both conceptual and mental design information to quantitative degrees of affordance using a fuzzy scale that provides user-to-designer information. The traditional communication channel has been hidden. In the past, design concepts were not a result of direct communication between designers and users. This study found that, based on users’ mental models, users can reflectively modify product characteristics to improve the convenience of usage. These insights offer a hidden communication channel for designers and are defined as generalised affordance within the context of this research. This study proposed a novel method to semi-quantify affordance using a fuzzy linguistic modelling technique to establish a fuzzy scale table that quantifies degrees of affordance. An affordance fuzzy matrix (AFM) was created to assess the effects of affordance of each task necessary to utilise each product component. The overall results of the AFM indicate the generalised affordance of a particular product. Hidden messages are the characteristic of a product improved by the user itself because of his habit, which incurs additional product features, symbols and words, and will help product designers for further design strategy and improvements. In this study, generalised affordance is applied to an electric oven as an example.     

基于价值工程的可适应性评价方法

可适应设计是为适应用户需求不断变化、降低资源消耗而提出的一种新的设计方法,对产品的可适应性进行评价是其关键技术之一.在分析可适应设计原则及实现途径的基础上,给出了一种基于价值工程的产品可适应性的评价方法.该方法将产品的资源消耗总量、产品性能以及用户的使用环境等因素综合考虑,将用户使用产品后获得的效益与在完成这一系列任务时所消耗的资源量的比值作为评价产品可适应性的指标.通过该方法,可以选择使用户在产品的全生命周期内资源消耗量最少的产品设计方案.最后,将该可适应性评价方法用于高效圆柱齿轮机床的设计中,验证了该方法的有效性.     

基于公理设计的产品设计解耦方法

针对利用公理设计理论进行产品设计时存在的很多耦合问题,综合应用公理设计理论与创新问题解决理论,提出利用创新问题解决理论中的矛盾矩阵来解决公理设计中耦合问题的一般方法,并通过打桩机的解耦设计对这一方法进行说明。     

Attribute selection for product configurator design based on Gini index

Customer needs play a critical role in product design. Matching diversified customer needs with a company’s product offerings has been a challenge for academia and industry. To this end, product configurator systems have been accepted as important tools to elicit customer needs to meet the challenge. However for complex products with many product possibilities and intricate inter-product relationships, current product configuration systems may become tedious and time consuming for customers’ choice navigation process. They cannot adapt to each individual customer’s preferences by leveraging on the attribute specification information captured in previous configuration steps. This paper presents a Gini index-based attribute selection approach for configurator design. Product configuring is modelled as a sequential query–answer process. In each configuring step, the Gini index is deployed to quantify the clarity of the designer’s beliefs about the customer’s needs. The attribute which contributes most to the clarity will be selected for the customer to configure. A product recommendation module is also integrated with the configurator to further improve the efficiency. As a result, designers obtain clarification on the customer’s needs and preferences in an accelerated manner. An example is presented to test the viability of the method.