计算机控制铝电解生产数据采集系统的实践

数据采集系统在计算机过程控制中有着十分重要的作用。本文介绍三菱公司可编程Ａ／Ｄ转换器Ａ１Ｓ６４ＡＤ、输出模板Ａ１ＳＹ１０和电压隔离传感器ＷＢ３２１组成的计算机控制铝电解生产数据采集系统设计方法,分析解决实际应用中出现的问题。     

交流采样测量电量的精度问题及解决方法

本文根据交流电量基本原理 ,分析了微机交流采样影响精度的因素 ,并探讨了解决的方法。     

基于图像抽样重组的2维核鉴别分析

2维核鉴别分析(2DKDA)存在离散度量矩阵过大而无法计算的问题。该文通过将图像抽样重组与2DKDA的结合,提出了3种基于图像抽样重组的2DKDA(SR2DKDA),它们不仅克服了2DKDA在计算上的困难,识别性能也优于2维线性鉴别分析(2DLDA)。在ORL人脸库和UMIST人脸库的实验验证了SR2DKDA的有效性。     

一种新的正形置换构造方法

正形置换在密码体制设计中应用广泛。该文基于正形置换和正形拉丁方截集的一一对应关系,研究了正形置换的构造问题,给出了由n元正形置换构造n+1元正形置换的新方法,该方法利用正形拉丁方An的一个截集及其补序截集,扩展得到正形拉丁方An+1的一个复合截集,并由此构造出正形拉丁方An+1的截集。证明了按这种方法由任一n元正形置换可以构造出22n个n+1元正形置换。     

Patents as technological information in Latin America

This study shows the importance of patents as a source of technological information in Latin America. We studied the industrial property offices’ websites and the kind of patent information available such as laws, gazette, statistics, cost, forms, and contacts. We found at the USPTO and PCT websites the quantity of patent applications from applicants in Latin American countries filed in these offices. Brazil and Mexico in particular provide information on their websites to anyone interested in filing patent applications, searching patents and using patents as a source of technological information. This work shows that the quantity of patent applications is only slowly increasing in Latin America. Thus, each one of the 21 countries of Latin America needs to have a policy of dissemination of the importance of the patent system as a source of technological information to increase research and innovation in their countries.     

我国海底取样设备的现状与发展趋势

本文介绍了我国常规海洋地质取样设备与新式取样设备的特点,提出了我国海底取样设备的发展趋势。     

Functional failure analysis of a thermal–hydraulic passive system by means of Line Sampling

Assessing the failure probability of a thermal–hydraulic (T–H) passive system amounts to evaluating the uncertainties in its performance. Two different sources of uncertainties are usually considered: randomness due to inherent variability in the system behavior (aleatory uncertainty) and imprecision due to lack of knowledge and information on the system (epistemic uncertainty).In this paper, we are concerned with the epistemic uncertainties affecting the model of a T–H passive system and the numerical values of its parameters. Due to these uncertainties, the system may find itself in working conditions that do not allow it to accomplish its functions as required. The estimation of the probability of these functional failures can be done by Monte Carlo (MC) sampling of the epistemic uncertainties affecting the model and its parameters, followed by the computation of the system function response by a mechanistic T–H code.Efficient sampling methods are needed for achieving accurate estimates, with reasonable computational efforts. In this respect, the recently developed Line Sampling (LS) method is here considered for improving the MC sampling efficiency. The method, originally developed to solve high-dimensional structural reliability problems, employs lines instead of random points in order to probe the failure domain of interest. An “important direction” is determined, which points towards the failure domain of interest; the high-dimensional reliability problem is then reduced to a number of conditional one-dimensional problems which are solved along the “important direction”. This allows to significantly reduce the variance of the failure probability estimator, with respect to standard random sampling.The efficiency of the method is demonstrated by comparison to the commonly adopted Latin Hypercube Sampling (LHS) and first-order reliability method (FORM) in an application of functional failure analysis of a passive decay heat removal system in a gas-cooled fast reactor (GFR) of literature.     

多路振动信号的伪同步采样及其在转子动平衡中的应用

对转子系统进行动平衡的关键在于对振动信号的整周期采样。给出了一种整周期采样的软件实现方法。对鉴相信号与振动信号进行同步采样，而对振动信号的整周期截取则利用软件实现。其优点在于可利用通用数据采集卡实现整周期采样。实验结果表明：这种方法可有效满足转子振动信号处理对信号采样的要求。     

Exposure to microbial components and allergens in population studies: a comparison of two house dust collection methods applied by participants and fieldworkers

Dust collection by study participants instead of fieldworkers would be a practical and cost-effective alternative in large-scale population studies estimating exposure to indoor allergens and microbial agents. We aimed to compare dust weights and biological agent levels in house dust samples taken by study participants with nylon socks, with those in samples taken by fieldworkers using the sampling nozzle of the Allergology Laboratory Copenhagen (ALK). In homes of 216 children, parents and fieldworkers collected house dust within the same year. Dust samples were analyzed for levels of allergens, endotoxin, (1-->3)-beta-D-glucans and fungal extracellular polysaccharides (EPS). Socks appeared to yield less dust from mattresses at relatively low dust amounts and more dust at high dust amounts than ALK samples. Correlations between the methods ranged from 0.47-0.64 for microbial agents and 0.64-0.87 for mite and pet allergens. Cat allergen levels were two-fold lower and endotoxin levels three-fold higher in socks than in ALK samples. Levels of allergens and microbial agents in sock samples taken by study participants are moderately to highly correlated to levels in ALK samples taken by fieldworkers. Absolute levels may differ, probably because of differences in the method rather than in the person who performed the sampling. Practical Implications Dust collection by participants is a reliable and practical option for allergen and microbial agent exposure assessment. Absolute levels of biological agents are not (always) comparable between studies using different dust collection methods, even when expressed per gram dust, because of potential differences in particle-size constitution of the collected dust.     

一种基于增量元模型方法的全局优化算法

针对复杂仿真模型的全局优化问题,提出一种基于增量元模型方法的全局优化算法。首先,分析了现有增量拉丁超立方采样方法新增点数量难以控制以及其数值必须为原采样点数量的整数倍的缺陷,在此基础上利用减法规则思想改进了增量拉丁超立方采样;其次,将改进后的增量拉丁超立方采样与径向基函数的增量更新方法相结合,提出了一种全新的高效全局优化算法;最后,将该算法应用于压力容器的优化设计,计算结果证明了该方法的实用性与工程有效性。