“…Unsupervised learning, also known as clustering, adopts k-means to establish a centriole and reduce error through iteration and descent to achieve classification. With the development of ML, more and more fields have begun to use this technique for research (Chen W. et al, 2016, Chen et al, 2017a,d, 2018a,b,e,f,g; Li et al, 2016; Zou et al, 2016, 2017; Ding et al, 2017a,b; Feng et al, 2017a; Yu et al, 2017a; Zeng et al, 2017a, 2018; Liu et al, 2018; Pan et al, 2018; Wei et al, 2018a,b; Yang et al, 2018a; Zhao et al, 2018b; He et al, 2019; Zhang et al, 2019), for example, drug repositioning (Yu et al, 2016b, 2017b), disease-related microRNA (Chen and Huang, 2017; Chen et al, 2017d, 2018b,e,g; Zhao et al, 2018a,c) identification, and disease-related long non-coding RNA identification (Chen and Yan, 2013; Chen et al, 2017e, 2018c; Hu et al, 2017, 2018). There are four main steps in developing ML algorithms (Oudah and Henschel, 2018).…”