张浩彬 (2022-08-10 22:51):
#paper 10.1609/aaai.v34i04.6056 在现实中,具备缺失值的时序很常见。在预测中,我们往往借助缺失位置的局部信息,或者全局均值等方式对缺失值进行插补在进行预测。但是对于缺失率较高,或存在连续缺失的情况,这些方法就可能不够了。本文提出了称为Lgnet的网络结构,在基于LSTM的基础上,对于多时间序列预测问题,借助其他序列的信息,对于序列的缺失值构建基于局部和全局的插补,并且结合gan增强对全局的估计 局部特征构造:经验均值和距离该值往后最近的一点 全局特征:对整体序列进行模式的识别(模式的数量是一个超参数),然后利用局部特征作为索引,找到相似的序列模式,并进行加权构造 以数据点的局部特征作为索引 最后对缺失值的估计有,由4部分取平均:经验均值,最近值,LSTM原始网络的预测值以及全局特征。另外,本文引入gan增强对输出的预测。 最后的实验来看:(1)Lgnet能够提高预测准确率;(2)对数据缺失率进行实验,Lgnet对缺失比例有比较强的鲁棒性。 消融实验:(1)基于内存模块所构造的全局特征,对数据确实的鲁棒性有比较重要的影响;(2)加入gan,能够提高2%-10%的预测精度,尤其是对缺失较高的数据集来说,引入gan更有利于捕捉全局的数据分布
Joint Modeling of Local and Global Temporal Dynamics for Multivariate Time Series Forecasting with Missing Values
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Abstract:
Multivariate time series (MTS) forecasting is widely used in various domains, such as meteorology and traffic. Due to limitations on data collection, transmission, and storage, real-world MTS data usually contains missing values, making it infeasible to apply existing MTS forecasting models such as linear regression and recurrent neural networks. Though many efforts have been devoted to this problem, most of them solely rely on local dependencies for imputing missing values, which ignores global temporal dynamics. Local dependencies/patterns would become less useful when the missing ratio is high, or the data have consecutive missing values; while exploring global patterns can alleviate such problem. Thus, jointly modeling local and global temporal dynamics is very promising for MTS forecasting with missing values. However, work in this direction is rather limited. Therefore, we study a novel problem of MTS forecasting with missing values by jointly exploring local and global temporal dynamics. We propose a new framework øurs, which leverages memory network to explore global patterns given estimations from local perspectives. We further introduce adversarial training to enhance the modeling of global temporal distribution. Experimental results on real-world datasets show the effectiveness of øurs for MTS forecasting with missing values and its robustness under various missing ratios.
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