基于退化数据和DBN算法的IGBT健康参数预测方法

绝缘栅双极型晶体管(IGBT)等电子元器件被广泛用于运输和能源部门,其健康状态对于设备安全和有效至关重要;在对IGBT的结构和损伤机制分析基础上,结合NASA艾姆斯中心开展的IGBT加速退化试验,选择集电极-发射极关断峰值电压作为失效特征参数,提出了一种基于深度信念网络的预测模型对其进行分析和预测;以Levenberg-Marquardt(LM)算法模型作为对比,实验结果显示文章提出的三隐藏层DBN模型相比于LM模型有更好的预测性能和更高的预测精度。     

基于深度学习的故障检测方法

针对传统故障诊断方法中特征提取技术难度大、故障样本获取困难等问题,在深度学习计算框架下提出了一种半监督训练的故障检测方法,利用深度信念网络中的受限波茨曼机堆栈结构实现了数据高层特征的自动提取,结合支持向量数据描述方法实现了异常数据检测,只需利用正常工况的数据样本进行网络训练和模型拟合,无需故障样本数据,也无需人工干预进行信号特征提取,即能实现对故障数据进行的实时检测和判别。经采用标准轴承实验数据的三组故障数据进行验证,故障识别率达到100%,具有很强的工程应用价值。     

交易者异质性与期货市场动态关系的仿真研究

本文构建了一个基于异质性交易者的投机性期货市场仿真模型,从交易者微观行为的角度分析市场价格的动态特征。市场中有限理性的交易者具有异质性信念和不同的学习能力。个体预期不断调整,市场根据密封拍卖机制出清,期货价格随之变化。仿真结果表明,价格的波动与市场中大投机交易者的活动密切相关。仿真能够再现期货价格波动高峰厚尾。长记忆等特征。噪声交易者在市场中的生存,取决于外部信息流对市场的影响过程以及其他交易者的行为.本文是采用计算金融学仿真方法研究衍生产品市场的一种尝试,也为此领域的研究者在模型的实现上提供了另外一种容易实现的途径。     

Disambiguation of social polarization concepts and measures

This article distinguishes nine senses of polarization and provides formal measures for each one to refine the methodology used to describe polarization in distributions of attitudes. Each distinct concept is explained through a definition, formal measures, examples, and references. We then apply these measures to GSS data regarding political views, opinions on abortion, and religiosity—topics described as revealing social polarization. Previous breakdowns of polarization include domain-specific assumptions and focus on a subset of the distribution’s features. This has conflated multiple, independent features of attitude distributions. The current work aims to extract the distinct senses of polarization and demonstrate that by becoming clearer on these distinctions we can better focus our efforts on substantive issues in social phenomena.     

近似空间与信任结构之间的关系

回顾了由二元关系产生的粗糙近似空间及其导出的各种粗糙近似算子的构造性定义,介绍了经典和模糊环境下各种信任结构及其导出的信任函数与似然函数的概念,给出了粗糙集理论中近似空间及其导出的下近似算子与上近似算子和证据理论中的信任结构及其导出信任函数与似然函数之间的相互关系及其应用背景。     

Change rules for hierarchical beliefs

The paper builds a belief hierarchy as a framework common to all uncertainty measures expressing that an actor is ambiguous about his uncertain beliefs. The belief hierarchy is further interpreted by distinguishing physical and psychical worlds, associated to objective and subjective probabilities. Various rules of transformation of a belief hierarchy are introduced, especially changing subjective beliefs into objective ones. These principles are applied in order to relate different contexts of belief change, revising, updating and even focusing. The numerous belief change rules already proposed in the literature receive epistemic justifications by associating them to specific belief hierarchies and change contexts. As a result, it is shown that the resiliency of probability judgments may have some limits and be reconciled with the possibility of learning from factual messages.     

Proper belief revision and rationalizability in dynamic games

In this paper we develop an epistemic model for dynamic games in which players may revise their beliefs about the opponents’ utility functions as the game proceeds. Within this framework, we propose a rationalizability concept that is based upon the following three principles: (1) at every instance of the game, a player should believe that his opponents are carrying out optimal strategies, (2) a player, at information set h, should not change his belief about an opponent’s relative ranking of two strategies s and s′ if both s and s′ could have led to h, and (3) the players’ initial beliefs about the opponents’ utility functions should agree on a given profile u of utility functions. Common belief in these events leads to the concept of persistent rationalizability for the profile u of utility functions. It is shown that for a given game tree with observable deviators and a given profile u of utility functions, every properly point-rationalizable strategy is a persistently rationalizable strategy for u. This result implies that persistently rationalizable strategies always exist for all game trees with observable deviators and all profiles of utility functions. We provide an algorithm that can be used to compute the set of persistently rationalizable strategies for a given profile u of utility functions. For generic games with perfect information, persistent rationalizability uniquely selects the backward induction strategy for every player.     

妈祖文化的社会功能及现代化意义

妈祖文化是中华文化之奇葩。它是一种海洋文化、和平文化、寻根文化、兼容文化和美德文化。在千年历史的传承和变异中,妈祖信仰文化的社会功能不断分化和演进。文章在分析妈祖信仰文化社会功用的基础上,从社会学的角度剖析了妈祖文化对社会经济、政治、文化和社会等各个领域,特别是对促进海峡两岸和平统一,繁荣海峡西岸经济区的重大而深远的影响。旨在准确把握妈祖信仰,进一步发挥妈祖信仰文化的影响力。     

A modification of the certainty measure to handle subnormal distributions

We suggest a modification of the definition of certainty associated with a possibility distribution so that we are assured that the certainty measure is always less than or equal to the possibility measure even in the face of subnormal distributions. We note that when the possibility distribution is normal this new definition reduces to the original definition of certainty. We use this new measure along with the definition of possibility measure to obtain measures of belief and plausibility in the fact of fuzzy information in the Mathematical Theory of Evidence.     

知识获取的多层证据网络模型

本文从诊断问题求解知识的一种组织形式——证据网络出发,讨论了将领域知识转换成证据网络的各种策略,并由此提出了知识获取的多层证据网络模型。根据该模型我们开发了交互式知识获取系统KAS-CEI,并将该系统用于汽车发动机故障诊断专家系统(AEFDES)知识库的建造。