seminars:datasci:200326
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| + | * Date: Tuesday, March 26, 2020 | ||
| + | * Time: 12:00pm -- 1:00pm | ||
| + | * Room: WH-100E | ||
| + | * Speaker: Wangshu Tu (Binghamton University) | ||
| + | * Title: A family of mixture models for biclustering | ||
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| + | Biclustering allows for simultaneous clustering of the observations and | ||
| + | variables. Martella et. al (2008) introduced biclustering in a model-based | ||
| + | clustering framework by utilizing a structure similar to a mixture of | ||
| + | factor analyzer structures such that observed variables are modelled using | ||
| + | a latent variable that is assumed to be from a MVN(0, I). In Martella et. | ||
| + | al (2008), clustering of variables was introduced by imposing constraints | ||
| + | on the entries of the factor loading matrix to be 0 and 1. However, this | ||
| + | approach restricts the non-zero off-diagonal entries of the covariance | ||
| + | matrix to be 1, which is very restrictive. Here, we assume the latent | ||
| + | variable to be from a MVN(0,T) where T is a diagonal matrix and hence, the | ||
| + | non-zero off-diagonal entires of the covariance matrix are not restricted | ||
| + | to be equal to 1. A family of models are developed by imposing constraints | ||
| + | on the components of the covariance matrix. An alternating expectation | ||
| + | conditional maximization(AECM) algorithm is used for parameter estimation. | ||
| + | Proposed method will be illustrated using simulated and real datasets. The | ||
| + | presentation will conclude with some on-going work and future research | ||
| + | directions. | ||
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