论文标题
在具有模糊时间序列的非平稳环境中进行预测
Forecasting in Non-stationary Environments with Fuzzy Time Series
论文作者
论文摘要
在本文中,我们介绍了一个非平稳模糊时间序列(NSFTS)方法,其时间变化的参数是根据数据的分布进行的。在这种方法中,我们采用非平稳模糊集,其中使用扰动函数来调整知识库中的成员资格函数参数,以响应时间序列中的统计变化。所提出的方法能够动态地调整其模糊集以基于残差误差反映随机过程中的变化,而无需重新审查模型。该方法可以处理非平稳和异性数据以及具有概念档的场景。提出的方法允许仅培训一次模型,并在保持合理准确性的同时很长时间保持有用。 The flexibility of the method by means of computational experiments was tested with eight synthetic non-stationary time series data with several kinds of concept drifts, four real market indices (Dow Jones, NASDAQ, SP500 and TAIEX), three real FOREX pairs (EUR-USD, EUR-GBP, GBP-USD), and two real cryptocoins exchange rates (Bitcoin-USD and Ethereum-USD).随着竞争对手的建模时间变体模糊时间序列和增量集合,这是处理非平稳数据集的两种主要方法。使用非参数测试来检查结果的重要性。提出的方法通过调整模型的参数来显示对概念漂移的韧性,同时保留了知识库的符号结构。
In this paper we introduce a Non-Stationary Fuzzy Time Series (NSFTS) method with time varying parameters adapted from the distribution of the data. In this approach, we employ Non-Stationary Fuzzy Sets, in which perturbation functions are used to adapt the membership function parameters in the knowledge base in response to statistical changes in the time series. The proposed method is capable of dynamically adapting its fuzzy sets to reflect the changes in the stochastic process based on the residual errors, without the need to retraining the model. This method can handle non-stationary and heteroskedastic data as well as scenarios with concept-drift. The proposed approach allows the model to be trained only once and remain useful long after while keeping reasonable accuracy. The flexibility of the method by means of computational experiments was tested with eight synthetic non-stationary time series data with several kinds of concept drifts, four real market indices (Dow Jones, NASDAQ, SP500 and TAIEX), three real FOREX pairs (EUR-USD, EUR-GBP, GBP-USD), and two real cryptocoins exchange rates (Bitcoin-USD and Ethereum-USD). As competitor models the Time Variant fuzzy time series and the Incremental Ensemble were used, these are two of the major approaches for handling non-stationary data sets. Non-parametric tests are employed to check the significance of the results. The proposed method shows resilience to concept drift, by adapting parameters of the model, while preserving the symbolic structure of the knowledge base.