Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:For evaluating the performance of our method, we used six comparative methods: the method using only visual features and applying MvLFDA to these visual features (C1), the method concatenating multiple visual features to one long vector and applying LPCCA to EEG features and the long vector (C2), and the methods applying LPCCA to EEG features and each visual feature and integrating multiple EEG-based visual features via simply concatenating them to one long vector (C3), MSE [18] (C4), Supervised MSE (SMSE) [21] (C5), and Multi-view Discriminant Analysis (MvDA) [32] (C6), where C2 and C3 applied LFDA to the long vector after concatenating multiple features.
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