Automatic clustering method based on evolutionary optimisation

How to set the cluster number plays a key role in many clustering applications. To address this issue, this study introduces an automatic clustering method based on evolutionary algorithms (EAs). The basic idea is to convert a clustering problem into a global optimisation problem and tackle it by an EA. A new validity index, which balances the inter-cluster consistency and the intra-cluster consistency, is proposed to be the objective function. Three adaptive coding schemes, which can deal with variable-length optimisation problems by using a fixed-length chromosome, are designed to detect the cluster number automatically. The validity index and adaptive coding schemes are incorporated in an EA for automatic clustering. The authors approach is compared with some widely used validity indices and an adaptive coding scheme on some artificial data sets and two real-world problems. The experimental results suggest that their method not only successfully detects the correct cluster numbers but also achieve stable results for most of test problems.