4 papers · 1 filter
Spectrally Tuned Bandwidth Selection for Kernel Fuzzy Relational Clustering
Efthymios Costa, John R. J. Thompson
Fuzzy clustering is used to identify overlapping geometric cluster structures through partial memberships. However, classical methods are limited by the assumption of equal variabl…
A unified approach to outlier identification for mixed-type data
Efthymios Costa, Christian Hennig
We present an outlier identification method for mixed type data sets comprising continuous and ordinal variables. We define outliers based on using a multivariate Gaussian distribu…
A Deterministic Information Bottleneck Method for Clustering Mixed-Type Data
Efthymios Costa, Ioanna Papatsouma, Angelos Markos
In this paper, we present an information-theoretic method for clustering mixed-type data, that is, data consisting of both continuous and categorical variables. The proposed approa…
A novel framework for quantifying nominal outlyingness
Efthymios Costa, Ioanna Papatsouma
Outlier detection is an important data mining tool that becomes particularly challenging when dealing with nominal data. First and foremost, flagging observations as outlying requi…