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针对传统信用风险评价模型只含有一个分类器的缺陷,本文利用AdaBoost组合分类器来对上市公司信用风险进行评价,并与基于支持向量机和神经网络的分类模型进行了效果比较。实证研究表明,组合分类器克服了单一分类器的诸多缺点,预测准确率高于单一分类器。 相似文献
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文章根据自组织神经网络的基本原理,结合55个边坡实例,应用matlab进行编程,建立了边坡影响因素分类处理的神经网络模型,并运用该模型对不同的边坡进行了分类,分类结果提高了神经网络的边坡指标数据的学习效率,从而证明了自组织神经网络对提高用于预测边坡稳定性神经网络性能的有效性。 相似文献
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本文研究了基于支持向量机的故障诊断方法。以传感器检测数据为输入,利用v-支持向量分类机进行故障分类识别。通过对柴油机燃油压力波动信息和柴油机振动监测数据的处理分析,结果显示基于支持向量机的故障分类器能够在样本有限的情况下出色的完成多种故障的诊断分类。 相似文献
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OSI参考模型;OSI七层模型称为开放式系统互联参考模型OSI七层模型是一种框架性的设计方法;OSI七层模型通过七个层次化的结构模型使不同的系统、不同的网络之间实现可靠的通讯,因此其最主要的功能就是帮助不同类型的主机实现数据传输。 相似文献
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将人工神经网络模型引入到工业品出厂价格指数预测领域,利用我国1990年-2008年的工业品出厂价格指数数据,建立了工业品出厂价格指数预测的人工神经网络模型。实验结果表明:基于BP算法的神经网络模型预测精度高,而且收敛速度快,它为工业品出厂价格指数预测工作提供了一种全新的方法。 相似文献
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Marco Costanigro Ron C. Mittelhammer Jill J. McCluskey 《Journal of Applied Econometrics》2009,24(7):1117-1135
We introduce a method for estimating multiple class regression models when class membership is uncertain. The procedure—local polynomial regression clustering—first estimates a nonparametric model via local polynomial regression, and then identifies the underlying classes by aggregating sample observations into data clusters with similar estimates of the (local) functional relationships between dependent and independent variables. Finally, parametric functions specific to each class are estimated. The technique is applied to the estimation of a multiple‐class hedonic model for wine, resulting in the identification of four distinct wine classes based on differences in implicit prices of the attributes. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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The argument that is put forward in this paper is that failure to represent stochastic trend and stochastic seasonality in an AIDS model leads to a misspecified and possibly structurally unstable model. This proposition is verified by estimating an AIDS model of the demand for alcoholic beverages in the United Kingdom. Three versions of the model are estimated, and it is demonstrated that the version allowing for stochastic trend and stochastic seasonality performs better than the other two versions of the model in terms of the diagnostics tests and goodness of fit measures. The best estimated model turns out to possess the properties of having common components and being homogenous. Further empirical testing reveals the presence of stochastic trends and cointegration between the budget shares of beer and wine. The results clearly indicate that there has been a shift away from the consumption of beer towards wine. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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为提高酒精蒸馏设备的生产效率和酒精产率,对纤维素燃料乙醇蒸馏工艺技术与设备进行了新的设计,该设计可满足固态蒸馏与液态蒸馏要求,具有一机多用的功能。本文研究了固态蒸馏与液态蒸馏过程中的蒸汽压力、填料系数、回流比对出酒率的影响并对关键影响因素进行了优化。结果表明:固态蒸馏时,回流比是影响出酒率的关键因素;最佳蒸馏工艺条件为蒸汽压力为0.4Mpa、填料系数为0.6、回流比为0.65。在此工艺条件下酒醅的出酒率达到最大值,即78.6%。液态蒸馏时,蒸汽压力是影响出酒率的关键因素;最佳提取工艺条件为蒸汽压力为0.3Mpa、填料系数为0.7、回流比为0.7,在此工艺条件下出酒率达到最大值,即78.9%。 相似文献
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《International Journal of Forecasting》2020,36(2):292-309
Agricultural price forecasting has been being abandoned progressively by researchers ever since the development of large-scale agricultural futures markets. However, as with many other agricultural goods, there is no futures market for wine. This paper draws on the agricultural prices forecasting literature to develop a forecasting model for bulk wine prices. The price data include annual and monthly series for various wine types that are produced in the Bordeaux region. The predictors include several leading economic indicators of supply and demand shifts. The stock levels and quantities produced are found to have the highest predictive power. The preferred annual and monthly forecasting models outperform naive random walk forecasts by 27.1% and 3.4% respectively; their mean absolute percentage errors are 2.7% and 3.4% respectively. A simple trading strategy based on monthly forecasts is estimated to increase profits by 3.3% relative to a blind strategy that consists of always selling at the spot price. 相似文献
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第三方逆向物流网络设计是否合理,直接对第三方逆向物流管理的效率和效益产生影响。文中对再制造逆向物流网络模型与算法进行了相关的设计与优化,给出了制造与再制造逆向物流网络的结构和功能,并对模型进行了实例分析,结果表明本模型对带有随机变量的约束条件满足的概率为94%,完全能够证明本模型对第三方逆向物流的优化网络的有效性。 相似文献
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分类是数据挖掘的重要组成部分,它根据类标号已知的数据建立模型,进而使用该模型来预测类标号未知的数据所属的类。KNN方法作为一种简单、有效、非参数的分类方法,在文本分类中得到广泛的应用,但是这种方法在训练样本的分布不均匀时会造成分类准确率的下降。针对KNN方法存在的这个问题,本文提出了一种基于相对距离的KNN分类方法,这种方法减少了边界点处测试样本的误判。实验结果显示,这种方法具有很好的性能。 相似文献
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The objective of this study is to determine factors influencing brand preferences of wine consumers in the Marmara region
where viniculture and wine production is so important in Turkey. First, the consumers’ preferences survey has been conducted
with 1022 persons in the region randomly selected and evaluated. Then, the informative factors influencing brand preferences
collected in these surveys have been determined by the multinomial logit model. A lot of independent variables have been used
in the multinomial logit model, but, because some independent variables were not found as significant according to Likelihood
Ratio test, these variables are not included in the multinomial logit analysis. Six important factors influencing wine brand
preferences have been determined. These factors are brand change causes of consumers, occupation of consumers, marital status
of consumers, birthplace of consumers, income of consumers and gender of consumers. In addition, whether the wine brand preferences
are independent, has been tested with Testing Independence of Irrelevant Alternatives of Hausman. According to this test,
it has been found that the wine brand preferences are independent. 相似文献