Question

list out the different methods of classification and write two points of each​

Answer 1

Sequence Classification

Most classification methods perform model construction based on feature vectors. However, sequences do not have explicit features. Even with sophisticated feature selection techniques, the dimensionality of potential features can still be very high and the sequential nature of features is difficult to capture. This makes sequence classification a challenging task.

Sequence classification methods can be organized into three categories: (1) feature-based classification, which transforms a sequence into a feature vector and then applies conventional classification methods; (2) sequence distance–based classification, where the distance function that measures the similarity between sequences determines the quality of the classification significantly; and (3) model-based classification such as using hidden Markov model (HMM) or other statistical models to classify sequences.

For time-series or other numeric-valued data, the feature selection techniques for symbolic sequences cannot be easily applied to time-series data without discretization. However, discretization can cause information loss. A recently proposed time-series shapelets method uses the time-series subsequences that can maximally represent a class as the features. It achieves quality classification results.