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北京富士通研发中心实习报告 邱 诚. 报告主题. 富士通的工作 Auto-Regressive and Moving Average Model (ARMA) 介绍 RHadoop 介绍. 富士通的工作. 研究数据选择方式; TBSC 均值法 指示性片段 优化 ARMA 模型和 SVR 模型; 动态结合 ARMA 模型和 SVR 模型;. 均值法描述. 基本步骤 查找与预测天 1~9 点的欧式距离最接近的五天; 将所得到的五天通过 10~20 点的欧式距离进行展; 将前两步得到的全部天通过 k-means 聚成两类;
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报告主题 • 富士通的工作 • Auto-Regressive and Moving Average Model (ARMA)介绍 • RHadoop介绍
富士通的工作 • 研究数据选择方式; • TBSC • 均值法 • 指示性片段 • 优化ARMA模型和SVR模型; • 动态结合ARMA模型和SVR模型;
均值法描述 • 基本步骤 • 查找与预测天1~9点的欧式距离最接近的五天; • 将所得到的五天通过10~20点的欧式距离进行展; • 将前两步得到的全部天通过k-means聚成两类; • 挑选预测天之前最接近的同一工作日作为判定天,和两个聚类中心计算欧式距离,挑选距离较小的聚类; • 将所得聚类中的各天求平均值作为预测结果。
ARMA模型介绍 • ARMA模型原理 • ARMA模型优化 • R中ARMA模型的使用
ARMA基本原理 Auto-Regressive model Moving Average model
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ARMA基本原理 • 自回归模型描述的是当前值与历史值之间的关系; • 滑动平均模型描述的是自回归部分的误差累计; • ARMA模型就是通过将自回归模型的预测值与累计误差相结合;
ARMA模型的优化 • Akaike’s Information Criterion (AIC) • AIC, Bias Corrected (AICc) • Bayesian Information Criterion (BIC) • 以上优化都是针对通过最大似然估计进行拟合得到的ARMA模型
AIC优化指标 :代表最大似然; :代表模型的参数个数;
R中ARMA模型的使用 • arima • auto.arima
arima函数 arima ( x, order = c(0, 0, 0), seasonal = list(order = c(0, 0, 0), period = NA), xreg = NULL, include.mean = TRUE, transform.pars = TRUE, fixed = NULL, init = NULL, method = c("CSS-ML", "ML", "CSS"), n.cond, optim.method = "BFGS", optim.control = list(), kappa = 1e6 )
auto.arima函数 auto.arima( x, d=NA, D=NA, max.p=5, max.q=5, max.P=2, max.Q=2, max.order=5, start.p=2, start.q=2, start.P=1, start.Q=1, stationary=FALSE, ic=c("aicc","aic", "bic"), stepwise=TRUE, trace=FALSE, approximation=(length(x)>100 | frequency(x)>12), xreg=NULL, test=c("kpss","adf","pp"), seasonal.test=c("ocsb","ch"), allowdrift=TRUE, lambda=NULL, parallel=FALSE, num.cores=NULL )
What need? • There is a need for more than counts and averages on these big data sets • Analyzing all of the data can lead to insights that sampling or subsets can’t reveal
Rhadoop用途 The open-source RHadoop project makes it easier to extract data from Hadoop for analysis with R, and to run R within the nodes of the Hadoop cluster -- essentially, to transform Hadoop into a massively-parallel statistical computing cluster based on R.
rhdfs • Manipulate HDFS directly from R • Mimic as much of the HDFS Java API as possible
rmr • Designed to be the simplest and most elegant way to write MapReduce programs • Gives the R programmer the tools necessary to perform data analysis in a way that is “R” like • Provides an abstraction layer to hide the implementation details