Community and topic detection (8)

Le16 - Fri Nov 21, 2025 Modularity: definition and matrix formalization; The Louvain algorithm for modularity optimization and its main characteristics; Solving greediness by consensus clustering; Generalizing modularity: the directed and signed network case; Modularity with overlapping communities.

Le17 - Mon Nov 24, 2025 Modularity with overlap: extending the Louvain approach; Modularity in the two-communities case: spectral approach; The normalised cut criterion; Suboptimal solution to normalised cut: algebraic connectivity and Fiedler's eigenvector; Conductance and the network community profile.

Le18 - Fri Nov 28, 2025 The InfoMap criterion: the node view, the community view, inside communities; Compact result; Normalized mutual information; Wrap-up on community assignment measures; The BigClam: rationale of a model-based approach, algorithm and performance.

Le19 - Mon Dec 1, 2025 Stochastic block models: Degree corrected SBMs; Mixed membership SBMs; Weighted SBMs; Dendrograms: divisive and agglomerative approaches; Girvan-Newmann method; HDBSCAN.

Le20 - Fri Dec 5, 2025 Clique percolation; Wrap-up on community detection; Semantic networks: The non-negative matrix factorization approach; generalized Kullback-Leibler divergence metric; Latent Dirichlet allocation: statistical model; performance.

Le21 - Fri Dec 12, 2025 Variational auto-encoders and the ELBO function; VAE for topic detection: NVDM, ProdLDA, DirVAE, NFTM, and NBVAE models.

Le22 - Mon Dec 15, 2025 NMF VAE-like model; The transformer architecture: BERT, BERTA, GPT-2, and GPT-3 models; BERTopic model and its performance; Wrap-up on topic detection.

Le23 - Fri Dec 19, 2025 Lab 5 - topic detection