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1.
炼钢过程中Cr的加入是一个逐步调整的过程,由于大量随机因素存在,使得Cr含量的测量值低于钢水中Cr的实际含量,从而导致过多Cr加入,成品钢中Cr含量偏高。为此,提出用RBF(Radial Basis Function)神经网络模型来估计钢水中Cr含量,寻求一组过程变量,通过主元分析降低输入维数,训练神经网络,对钢水中Cr含量进行有效估计,该方法可以一次性调整Cr的含量到要求范围内.  相似文献   

2.
以品位实测数据为基础,提出了科学发现矿体真实品位估计公式的遗传规划方法。该方法根据自然界生物生存竞争、适者生存的进化法则,对众多随机生成的品位估计公式进行类似于生物进化时发生的复制、交换、变异等若干个结构改良操作,淘汰极不合理的估计公式,改良较合理的估计公式,最后优选出能真实、全面描述矿体品位分布的品位估计公式。该方法完全排除了人为的参数预给定,具有很好的客观性、通用性和精确性。  相似文献   

3.
本文首先讨论了对数正态分布及三参数对数正态分布理论,然后重点研究了对数正态克立格法。在分析了无偏条件及最小估计方差之后,给出了对数正态克立格法方程组及对数克立格方差。克立格权系数λa即为该方程组的解。据此,可以估计矿床中每一块段的克立格估值Zv,该估值是具最小估计方差的无偏线性估计量。该法已用于一个铁铜矿床的储量计算。  相似文献   

4.
《铁合金》2006,37(6):42-42
据估计。中国今年的不锈钢产量预计将增长60%。达510万t。据悉。中国不锈钢的消费可能增长16%,达615万t。同时。不锈钢进口将达260万t,仅出口60万t。中国不锈钢的产能已经急速攀升,估计将从2005年的800万t升至2006年的1200万t。  相似文献   

5.
张祯文 《南钢科技》2001,(4):33-34,41
设计不合理,施工人员熟悉图纸和规范不够,施工质量不佳,造成构造柱钢筋漏放、偏位,搭接长度不够,施工缝处断高,砼强度偏低等问题。针对以上问题,分析原因,采用增加钢筋,合理折钢筋,加强焊,增大柱截面等处理方法。  相似文献   

6.
简述了氧化钴的生产流程,着重分析了煅烧过程影响氧化钴主成分的因素,及其控制方法,以确保氧化钴的质量。  相似文献   

7.
国际镍业研究组织(INSG)10月8日称,2009年全球镍供应料过剩70000吨,且2010年全球镍市供应过剩量料增加至90000吨。INSG称,估计全球今年的镍需求量料较上年下滑6%,尽管来自不锈钢行业的需求已经回升。INSG估计2009年全球镍需求量为121万吨,低于2008年的129万吨。该组织称,估计明年镍需求料继续回升,料增加至135万吨。  相似文献   

8.
距离幂次反比法品位估计公式中参数确定的遗传算法   总被引:1,自引:0,他引:1  
应用遗传算法提出了自动确定距离幂次反比法品位估计公式中最优幂次的方法。该方法根据生存竞争的自然进化法则,对众多随机生成的幂次进行类似于生物进化时发生的复制、交换、变异等若干个改良操作,淘汰极不合理的幂次,改良较合理的幂次,最后优选出具有很高品位估计精度的幂次。该方法完全不依赖人,具有很好的客观性和通用性。  相似文献   

9.
高寅元 《特殊钢》1990,11(3):1-6
提出了钢材控制轧制应用估计技术的概念,从新钢种研制和TMCP处理技术两个侧面介绍了国内外在该领域中的进展,继而希望有关科技人员注意,在控制轧制技术中加强预估计和在线估计技术的研究和应用。  相似文献   

10.
布隆迪能源与矿业部长萨米埃尔·恩达伊拉吉杰10月8日表示,布隆迪日前在该国东南部和和中部共发现三处镍矿层,估计镍储备约为420万t,可供开采50年。  相似文献   

11.
导出了随机-模糊线性回归模型参数的估计量,证明了参数的估计量为无偏估计,同时推导了参数估计量数字特征和回归方程相关系数的计算公式。将该模型应用于岩石样本抗剪强度实验数据处理中,通过与传统的随机一元线性回归对比分析,表明使用该方法得到的力学参数更具代表性。  相似文献   

12.
Principal components analysis (PCA) is used to explore the structure of data sets containing linearly related numeric variables. Alternatively, nonlinear PCA can handle possibly nonlinearly related numeric as well as nonnumeric variables. For linear PCA, the stability of its solution can be established under the assumption of multivariate normality. For nonlinear PCA, however, standard options for establishing stability are not provided. The authors use the nonparametric bootstrap procedure to assess the stability of nonlinear PCA results, applied to empirical data. They use confidence intervals for the variable transformations and confidence ellipses for the eigenvalues, the component loadings, and the person scores. They discuss the balanced version of the bootstrap, bias estimation, and Procrustes rotation. To provide a benchmark, the same bootstrap procedure is applied to linear PCA on the same data. On the basis of the results, the authors advise using at least 1,000 bootstrap samples, using Procrustes rotation on the bootstrap results, examining the bootstrap distributions along with the confidence regions, and merging categories with small marginal frequencies to reduce the variance of the bootstrap results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
Forecasting the likely cost of construction work before tendering is known as to be a hazardous task. Both underestimates and overestimates may present problems to clients and contractors. Not surprisingly, cost-engineering activities can be stressful for those responsible. Coping with the stresses requires action on the part of the individuals affected and the organizations to which they belong. This paper examines the effect of organizational supports in the process of project estimation through a survey of construction estimation participants in Hong Kong. Using correlation analysis and regression analysis, it is found that: (1) the stressors of autonomy and feedback are directly related to the stress experienced by cost engineers; (2) informal organizational supports (particularly concerning relationship conflict, Type A behavior, work underload, lack of autonomy, and unfair rewards and treatment) are far more effective than formal supports in reducing stress; and (3) lack of autonomy and lack of feedback are predictable variables affecting stress. Cost-engineering managers and supervisors need to carefully distinguish between those who prefer hands-on support and those who prefer hands-off support. A good communication and team decision-making process and a fair reward and treatment system may help establish close relationships among cost engineers in a company and ensure sufficient autonomy to cost engineers and the participants in the estimation process.  相似文献   

14.
An approach to sample size planning for multiple regression is presented that emphasizes accuracy in parameter estimation (AIPE). The AIPE approach yields precise estimates of population parameters by providing necessary sample sizes in order for the likely widths of confidence intervals to be sufficiently narrow. One AIPE method yields a sample size such that the expected width of the confidence interval around the standardized population regression coefficient is equal to the width specified. An enhanced formulation ensures, with some stipulated probability, that the width of the confidence interval will be no larger than the width specified. Issues involving standardized regression coefficients and random predictors are discussed, as are the philosophical differences between AIPE and the power analytic approaches to sample size planning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

15.
How do people make quantitative estimations, such as estimating a car's selling price? Traditionally, linear-regression-type models have been used to answer this question. These models assume that people weight and integrate all information available to estimate a criterion. The authors propose an alternative cognitive theory for quantitative estimation. The mapping model, inspired by the work of N. R. Brown and R. S. Siegler (1993) on metrics and mappings, offers a heuristic approach to decision making. The authors test this model against established alternative models of estimation, namely, linear regression, an exemplar model, and a simple estimation heuristic. With 4 experimental studies the authors compare the models under different environmental conditions. The mapping model proves to be a valid model to predict people's estimates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

16.
单位工程概算是初步设计概算中的基础,工作量最大,也是至关重要的一个部分。结合概算编制经验,从建筑工程和设备及安装工程两类工程的概算编制的特点入手,分析了编制准确、全面的单位工程概算应注意的具体事项。  相似文献   

17.
张敬华 《河南冶金》2003,11(4):22-24
介绍了测量不确定度的概念、分类、评估的意义及测量不确定度的来源,阐述了测量不确定度评估的一般程序,并通过对凯尔文电桥法测量Tu2线材导电率不确定度的评定实例,进一步说明了其评估的方法。  相似文献   

18.
:本文以样本年数据为基础,通过数理统计确定占成本构成份额98%的18种物资;在计算模型设计中,引进与机时产量成反比的“生产系数”和与品种总成本成正比的品种系数;解决费用分排问题。企业的成本要素一旦发生变化,本计算模型可立即计算出企业的全部有关产品生产成本和销售成本。  相似文献   

19.
The authors provide a didactic treatment of nonlinear (categorical) principal components analysis (PCA). This method is the nonlinear equivalent of standard PCA and reduces the observed variables to a number of uncorrelated principal components. The most important advantages of nonlinear over linear PCA are that it incorporates nominal and ordinal variables and that it can handle and discover nonlinear relationships between variables. Also, nonlinear PCA can deal with variables at their appropriate measurement level; for example, it can treat Likert-type scales ordinally instead of numerically. Every observed value of a variable can be referred to as a category. While performing PCA, nonlinear PCA converts every category to a numeric value, in accordance with the variable's analysis level, using optimal quantification. The authors discuss how optimal quantification is carried out, what analysis levels are, which decisions have to be made when applying nonlinear PCA, and how the results can be interpreted. The strengths and limitations of the method are discussed. An example applying nonlinear PCA to empirical data using the program CATPCA (J. J. Meulman, W. J. Heiser, & SPSS, 2004) is provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

20.
对工程概算调整的一些思考   总被引:1,自引:0,他引:1  
对调整概算的原因、重点和途径进行了探讨和分析研究,以期达到准确编制工程概算、合理调整概算的目的。  相似文献   

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