Assessing the quality of identified models through the asymptotic theory—when is the result reliable?

In this paper, the problem of estimating uncertainty regions for identified models is considered. A typical approach in this context is to resort to the asymptotic theory of Prediction Error Methods for system identification, by means of which ellipsoidal uncertainty regions can be constructed for the uncertain parameters.We show that the uncertainty regions worked out through the asymptotic theory can be unreliable in certain situations, precisely characterized in the paper.Then, we critically analyze the theoretical conditions for the validity of the asymptotic theory, and prove that the asymptotic theory also applies under new assumptions which are less restrictive than the usually required ones. Thanks to this result, we single out the classes of models among standard ones (ARX, ARMAX, Box-Jenkins, etc.) where the asymptotic theory can be safely used in practical applications to assess the quality of the identified model.These results are of interest in many applications, including iterative controller design schemes.     

Morphologic and cathodoluminescence studies of diamond films by scanning electron microscopy

Using recent papers on scanning electron microscopy (SEM) of chemical vapor deposition (CVD) diamond films, two analytical applications of the SEM are discussed: the morphologic investigations (secondary electron emission mode) and the recognition of impurities and defects [cathodoluminescence (CL) mode]. Studies of CVD diamond films by SEM demonstrate that the morphologies of these films are affected by synthesis conditions, especially by substrate temperature, methane concentration, and total pressure in the reactor. CL spectra and images are useful tools for clarifying the relationship between emission centers and different types of defects generated during the process of diamond crystal growth. The paper shows that the investigations of the morphology, crystallinity, local CL emission, as well as the surface distribution of CL spectra on CVD diamond films by SEM led to the correlative information for quality estimation of films in comparison with natural diamond.     

Defects tracking matrix for mass customization production based on house of quality

The vision of mass customization has driven a movement toward low volume, high variety mass customization production (MCP) at low price. However, defect identification and defect tracking in such systems are extremely difficult because of the frequent reconfiguration needed by the number of different part types and the interruption of the information flow about quality with each reconfiguration of the system. It is important to quickly rebuild quality information flow with MCP system’s reconfiguration synchronously. This paper introduces a defect tracking method based on Quality Function Deployment for every MCP system module. A defects tracking matrix (DTM) based on the House of Quality directly connects manufacturing technologies with quality defects inside a MCP module. Each MCP reconfiguration requires the DTMs’ rearrangement and DTM-chain is proposed. A dynamic reconstructing algorithm synchronizes the DTM-chain with each MCP reconfiguration. A case study demonstrates the usefulness of the DTM and DTM-chain.

一种包装质量视觉检测软件的通用模型

在现代工业自动化生产中，有许多包装质量检测任务，一般这些工作是靠人工检测完成的．但是人工检测通常无法达到满意的检测效果，而机器视觉则非常适合于包装质量检测。本文描述了一种包装质量视觉检测系统中检测软件的通用模型。     

Quality evaluation model using loss function for multiple S-type quality characteristics

Most of the studies of quality system or product-quality assessment deal with a single quality characteristic to determine the quality loss. Products are often assessed on more than one quality characteristic. For this reason, different multivariate quality loss functions have been proposed. However, these loss functions only consider the nominal-the-best quality characteristics (N-type); they do not consider the condition when the quality characteristics are of the smaller-the-better (S-type). In this article, we present a quality evaluation model using loss function for multiple S-type quality characteristics. A numerical example is illustrated showing that using inappropriate loss functions will lead to inaccurate results that give either an underestimate or overestimate of the expected quality costs.     

易拉罐用铝板材冶金质量比较分析

比较分析了当前国内所使用的几种易拉罐用铝板材与经高效熔体处理的试验铝板材的冶金质量和力学性能。结果表明：现用铝板中的夹杂物大多数为较粗大的复合夹杂物且含量较高；小块状第二相粒子大小相当，但均大于试验板材中的第二相尺寸，且分布不均匀性较明显；国产板材的常温拉伸性能低于国外板材，在三种板材中其各向异性最明显。经高效熔体处理的铝材中的夹杂物以细小Al2O3为主，夹杂物质量分数仅为0．273％；细小第二相均匀分布于基体，大多数为（Al，Fe，Mn，Mg，Si，RE）复合相；拉伸断口韧窝呈近等轴状，与国产板材相比，抗拉强度、屈服强度与伸长率分别提高9．1％、19．6％和12．8％，主要力学性能基本达到（有的甚至略优于）国外板材的性能水平。     

工业设备预防性维修策略及其效果评估

采用随机变量评估工业设备预防性维修的效果,以单位时间平均维修费用最低为目标,并假定评估预防性维修效果的参数服从均匀分布,构建维修策略的优化模型并进行数值仿真.仿真结果表明,采用随机参数的预防性维修模型能有效降低故障率增长趋势,减少单位时间平均维修费用,具有更好的优化结果,可以为维修计划的制定和现场的作业调度提供决策支持.     

数控车床程序编制中辅助指令的使用技巧

针对经济型数控车床的使用中常遇到的实际问题，在加工轴、孔、球类零件时，使用G00、G92、G26、G27、G29及间隙补偿指令可用的技巧和注意事项；在提速的同时充分考虑指令使用与实际位移轨迹、累计误差、工序安排、运行速度、间补次数等多种因素，使编程简单化的同时提高加工精度，最大效益的发挥经济型数控车床的作用。     

随机森林算法在空气质量评价中的应用

为了更好地反映空气质量的变化趋势,加强大气污染的防治,开展城市环境空气质量评价的意义重大。有效的空气质量评价方法可以提高评价体系的科学性,督促各个城市环保工作的稳步推进,从而对大气污染治理做出贡献,而空气质量评价算法是空气质量评价的核心。根据影响空气质量的几个基本要素:二氧化硫年平均浓度、二氧化氮年平均浓度、可吸入颗粒物年平均浓度等,创新性地采用随机森林算法对我国113个重点城市的空气质量进行了评价。通过评价指标将模型的评价结果与其他分类算法进行比较,发现随机森林分类模型,无论是在二分类还是多分类中都能够对各个城市地区的空气质量作出较为准确的评估,并进一步得出空气中PM10、PM2.5和O3的浓度是影响各大城市空气质量好坏的主要因素。     

引入积极心理学理念开展大学生心理健康教育的思考

目前高校心理健康教育主要为消极心理学模式,削弱了学校心理健康教育的积极作用。积极心理学则主张对人自身拥有的积极品质进行研究,重视学生积极的心理体验。教育工作者应当在大学生心理健康教育中借鉴积极心理学的研究成果,更新观念、开阔视野,用开放的、欣赏的眼光去看待学生,并努力促进学生知情意的统一,达到增强学生心理素质的目的。