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提高灰建模数据列光滑度的一种新方法 被引量:15
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作者 郑锋 魏勇 《统计与决策》 CSSCI 北大核心 2007年第18期37-38,共2页
本文在对建模数据序列进行一定处理的基础上,提出了经函数cosx变换来提高数据光滑度的方法,理论上证明了这种变换可以有效地提高建模数据列的光滑度,其模型精度优于对数及幂函数变换所建模型的精度;并通过实例表明了该方法的有效性。
关键词 GM(1 1) 光滑度 建模数据列 函数变换
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Modeling the growth and policy implications of Global System for Mobile Telecommunication (GSM) in Nigeria
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作者 Bakare Adewale Stephen 《Chinese Business Review》 2010年第10期33-40,共8页
This paper investigated the growth and policy implications of Global System for Mobile Communication in Nigeria. Stochastic economic modeling was used to analyze Nigeria's time series data. The models were adjudged r... This paper investigated the growth and policy implications of Global System for Mobile Communication in Nigeria. Stochastic economic modeling was used to analyze Nigeria's time series data. The models were adjudged reliable before they were used. The components of the model were defined and a prior expectation of the relationship among the variables explained for the purpose of giving the reviewers and users a deep insight into the phenomenon under study. The secondary data used for the study were processed using the E-View for windows electronic packages. The outcome of the empirical and stochastic investigations shows that Global System for Mobile Communication has a positive relationship with output growth in Nigeria. The impact is of a higher magnitude. The usage of Global System for Mobile Telecommunication led to 17 percent rise in the output growth. The findings suggest the need for the Nigerian Communication Commission (NCC) and the federal government of Nigeria to expand tele-density and directly make telephone communications cheap and accessible. To achieve this goal, more licenses should be given to GSM operators in order to allow for healthy competition among them. This will lead to improved quality of services, quality of product and consequently sustain the growth and development of the country. 展开更多
关键词 Global System for Mobile Communication (GSM) tele-density economic growth DEREGULATION
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A time-series modeling method based on the boosting gradient-descent theory 被引量:5
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作者 GAO YunLong PAN JinYan +1 位作者 JI GuoLi GAO Feng 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第5期1325-1337,共13页
The forecasting of time-series data plays an important role in various domains. It is of significance in theory and application to improve prediction accuracy of the time-series data. With the progress in the study of... The forecasting of time-series data plays an important role in various domains. It is of significance in theory and application to improve prediction accuracy of the time-series data. With the progress in the study of time-series, time-series forecasting model becomes more complicated, and consequently great concern has been drawn to the techniques in designing the forecasting model. A modeling method which is easy to use by engineers and may generate good results is in urgent need. In this paper, a gradient-boost AR ensemble learning algorithm (AREL) is put forward. The effectiveness of AREL is assessed by theoretical analyses, and it is demonstrated that this method can build a strong predictive model by assembling a set of AR models. In order to avoid fitting exactly any single training example, an insensitive loss function is introduced in the AREL algorithm, and accordingly the influence of random noise is reduced. To further enhance the capability of AREL algorithm for non-stationary time-series, improve the robustness of algorithm, discourage overfitting, and reduce sensitivity of algorithm to parameter settings, a weighted kNN prediction method based on AREL algorithm is presented. The results of numerical testing on real data demonstrate that the proposed modeling method and prediction method are effective. 展开更多
关键词 time-series forecasting BOOSTING ensemble learning OVERFITTING
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