Reliability-based robust design optimization: A general methodology using genetic algorithm

In this paper, we present an improved general methodology including four stages to design robust and reliable products under uncertainties. First, as the formulation stage, we consider reliability and robustness simultaneously to propose the new formulation of reliability-based robust design optimization (RBRDO) problems. In order to generate reliable and robust Pareto-optimal solutions, the combination of genetic algorithm with reliability assessment loop based on the performance measure approach is applied as the second stage. Next, we develop two criteria to select a solution from obtained Pareto-optimal set to achieve the best possible implementation. Finally, the result verification is performed with Monte Carlo Simulations and also the quality improvement during manufacturing process is considered by identifying and controlling the critical variables. The effectiveness and applicability of this new proposed methodology is demonstrated through a case study.     

Experimental design in soap manufacturing for optimization of fuzzified process capability index

In manufacturing industries, the quality of a product depends on the combined effect of multiple input variables working singly or together and therefore attention has been given on process capability indices to shift from single to multivariate domain. In case of multivariable domain the capability to incorporate uncertainties at the time of decision making becomes necessary. Fuzzy system is introduced to take care of this requirement. In this article the process parameters of soap manufacturing industries have been analyzed. The process capability is determined using Fuzzy Inference System rule editor based on a set of justified if then statements as applicable for the process. The data has been collected in linguistic form to derive its process capability, using a set of justified rules and the effect of each factor has been determined using Design of Experiments (DoE) and analysis of variance technique (ANOVA) for improving the soap quality from perspective of its softness. This article ventures to propose a new methodology by integrating Fuzzy with DoE providing better result followed by DoE and Fuzzy Inference system in isolation.     

考虑水软化-化学风化作用的岩石单轴压缩试验离散元模拟

西南地区以岩石地形为主,较为潮湿。而岩石在工程长期运行中,会受到水和化学风化作用的影响,分别表现出软化、强度降低以及力学性能劣化的特性。因此研究岩石在水、化学风化作用影响下的力学性质极其重要。本文采用离散单元法(DEM)模拟水软化-化学风化因素作用下岩石的单轴压缩试验,得到应力应变曲线以及破坏后微观信息图,从宏微观角度分析岩石受水、化学风化作用下力学性质,破坏模式的变化。模拟结果表明:随着岩石饱和度的增加,岩石的峰值强度、弹性模量不断减小,破坏模式由压剪扭破坏为主逐渐转变为拉剪扭破坏为主;随着化学风化程度增大,岩石峰值强度也随之减小,脆性破坏特征越来越不明显,与室内试验结果相吻合。     

三轴应力下盐岩声发射特征研究（研究生论坛稿件）

利用MTS815 Flex Test GT岩石力学试验系统和PCI–2声发射(AE)三维定位实时监测系统,开展不同围压下盐岩的三轴压缩声发射定位试验,探讨盐岩轴向加载过程中声发射特征的围压效应。研究结果表明：盐岩AE定位点多少与振铃计数率大小、能率高低具有良好的一致性。声发射高计数、高能率、定位点集聚段等随围压增加而滞后。低围压下,盐岩发生剪切破坏,高计数、高能率、AE定位点集聚段主要出现在屈服阶段和峰值应力前阶段;高围压下,盐岩呈塑性大变形特征,高计数、高能率、AE定位点集聚段主要在峰值阶段及峰后阶段出现。围压增加,累计计数和定位点的总量呈减少趋势;最大能率和累计能量随围压增加而减小,5MPa约分别为30MPa的43倍和22倍。     

一种木材粘合剂胶接强度新型试验装置的研制

设计了一种由基础框架、加载液压千斤顶、测力弹簧、读数百分表和试样夹具组成的木材粘合剂胶接强度试验装置。有限元数值分析与通用材料试验机的测试比较结果表明：该装置可满足JIS K6852标准的要求，且具有结构简单、体积小、测量可靠和便捷的特点。     

Synthesis and electrochemical characteristics of Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials for lithium ion batteries

LiNi_1/3Co_1/3Mn_1/3O₂ cathode materials have been coated with Al₂O₃ nano-particles using sol-gel processing to improve its electrochemical properties. The X-ray diffraction (XRD) pattern of the as-prepared Al₂O₃ nano-particles was indexed to the cubic structure of the γ-Al₂O₃ phase and had an average size of ∼4 nm. The XRD showed that the structure of LiNi_1/3Co_1/3Mn_1/3O₂ was not affected by the Al₂O₃ coating. However, the Al₂O₃ coatings on LiNi_1/3Co_1/3Mn_1/3O₂ improved the cyclic life performance and rate capability without decreasing its initial discharge capacity. These electrochemical properties were also compared with those of LiAlO₂-coated LiNi_1/3Co_1/3Mn_1/3O₂ cathode material. The electrochemical impedance spectroscopy (EIS) was studied to understand the enhanced electrochemical properties of the Al₂O₃-coated LiNi_1/3Co_1/3Mn_1/3O₂ compared to uncoated LiNi_1/3Co_1/3Mn_1/3O₂.     

无理数字典码的测试数据压缩方案

提出了一种无理数字典码的测试数据压缩方案,能有效地压缩芯片测试数据。方案利用无理数序列建立字典,编码时只需进行相容性检查,无需填充无关位,简化了操作步骤;同时,选择局部压缩率最大的一组数据作为最终编码结果,保证压缩效果可以达到局部最优。对ISCAS 89标准电路Mintest集的实验结果显示,该方案的压缩效果优于传统压缩方法,如Golomb码、FDR码、混合定变长码等。     

Hadoop平台下的分形图像压缩编码

借助Hadoop平台实现了分形图像压缩编码,并将其应用于云渲染中对渲染后的图像进行压缩并传至用户阶段。采用4台PC机搭建Hadoop平台,并在此基础上进行分形图像压缩编码,实验结果表明,采用4台PC机的Hadoop平台并行压缩时间不到单台PC机压缩时间的30%,证实了该方案的现实有效性。采用分形压缩编码将云渲染后的图像传给用户具有压缩比大、传输时间短、解压缩快等特点,对改善云渲染用户体验具有重要意义。     

规模储氢技术及其研究进展

介绍了几种常用的储氢技术如高压压缩储氢技术、吸氢物质强化压缩储氢技术、液化储氢技术和金属氢化物储氢技术的研究进展,并对规模储氢技术的发展前景进行了预测和展望,指出规模储氢技术目前急待解决的问题是提高储氢密度、储氢安全性和降低储氢成本。     

一种基于随机GA的提高BP网络泛化能力的方法

LM-BP网络对其初始权值和阈值敏感,泛化能力不强,针对该缺点,采用遗传算法（GA）对其初始权阈值进行优化,在一定程度上能提高LM-BP网络的泛化能力。为进一步扩展GA初始种群的覆盖范围,进一步提高LM—BP网络的泛化能力,采用多次随机产生初始种群多次优化的方法。以伦河孝感段氟化物含量为实例,建立随机GA的LM—BP网络模型,对原始数据进行拟合及测试,结果表明该方法基本能100％拟合,测试误差不超过2．3％。经过对比实验,证明了该方法的有效性。