INP9087851 - NETWORK SCIENCE 2023-2024
Topic outline
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Lecture hours (starting October 2, 2023)
Mon 8:30-10:00, room Me
Fri 10:30-12:00, room EeIn classroom teaching
This year the course unit is delivered in classroom!Instructor
Tomaso Erseghe, tomaso.erseghe@unipd.itOffice hours
contact me during lectures, or send me an email for an appointmentTentative calendar 23/24
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The course slides (and material) have been updated this year, some are already available, some will be posted asap
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Le1 - Mon Oct 2, 2023 Introduction to the course: elearning site, projects and interdisciplinary projects, network examples, contents overview, exam dates.
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Le2 - Fri Oct 6, 2023 Networks as graphs; Directed and undirected networks; Paths, Cycles, Diameter; Adjacency matrix; Nodes degrees and the degree distribution; Sparsity; Bipartite graphs; Signed graphs; Connectivity.
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Le3 - Mon Oct 9, 2023 Degree centrality; Power law versus Poisson distribution; Estimation methods for the degree exponent: ML approach; Explaining the power law; Erdos-Renyi random model: binomial and Poisson descriptions of the model; Small world; Power law versus Poisson distribution; Growth and preferential attachment; the Barabasi-Albert model.
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Le4 - Fri Oct 13, 2023 Attractiveness and the Bianconi-Barabasi model; Analysis of the Bianconi-Barabasi model; Examples with equal and uniform fitness; Measuring fitness: the www; Other ideas for modelling the power-law.
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Le5 - Mon Oct. 16, 2023 Properties of the power-law: largest hub, moments and scale-free networks, distances; Centrality measures; PageRank: random walk, dead ends and spider traps, teleportation; PageRank with restart; PageRank versus degree centrality; convergence properties of PageRank.
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Le6 - Tue Oct. 18, 2022 PageRank matrix structure via the condensation graph; Action of the teleport vector: one leaf-only, one eigenvalue set to 1 and the rest to (at most) c; Interpretation; Tuning the teleport vector: Local PageRank; Examples of application; Approximate PageRank and the push operation: proof of the precision guarantee; Application to link prediction; Topic specific PageRank.
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Le7 - Mon Oct 23, 2023 Topic specific Pagerank; Signed PageRank; Preventing spamming; Row-normalized PageRank; HITs centrality; Eigenvector and Katz centralities and their relation to PageRank and Degree centrality.
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Le8 - Fri Oct 27, 2023 Closeness and harmonic centrality; Betweenness centrality as a measure of brokerage; The clustering coefficient; Wrap-up on centrality measures.
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Le8 - Fri Oct 27, 2023 Community detection problem: Granovetter's view and the role of weak ties; The core-periphery model and overlapping communities; Modularity: definition.
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Le9 - Mon Oct 30, 2023 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.
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Le10 - Fri Nov 3, 2024 Modularity with overlapping communities; 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.
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Le11 - Mon Nov 6, 2023 Interdisciplinary projects overview and deadlines; The InfoMap criterion: the node view, the community view, inside communities; Compact result.
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Le12 - Fri Nov 10, 2023 Normalized mutual information; Wrap-up on community assignment measures; The BigClam: rationale of a model-based approach; The BigClam: algorithm and performance; Stochawtic block models: Degree corrected SBMs; Mixed membership SBMs; Weighted SBMs.
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Le13 - Mon Nov 13, 2023 Dendrograms: divisive and agglomerative approaches; Girvan-Newmann method; HDBSCAN; Clique percolation; Wrap-up on community detection; Correlation networks.
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Le14 - Fri Nov 17, 2023 The layout problem; Aesthetic criteria; Spring-embedder algorithm; Repulsive and attractive forces; Fruchterman & Reingold; Force atlas 2; Gravity; Approximate repulsion; UMAP as a force-layout algorithm; Software tools.
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Le16 - Fri Nov 24, 2023 Presentation of interdisciplinary projects -- hall room (Aula Magna Lepschy), DEI/D building, at the back of the main building facing the Piovego Canal, see https://www.dei.unipd.it/en/department/map-department
10:30 LoveYourSelf: bodyshaming from fashion industry
10:35 Fast Fashion Fighters: Shein’s brand morality through the eyes of social media audiences
10:40 popsTar: Miquela AI popstar and emotional impact on her audience
10:45 Barbie: How has the Barbie Movie by Greta Gerwig influenced the discussion about feminism?
10:50 Abortion Right: revocation of Abortion Right in USA (2022) and reaction of the public opinion
10:55 PI: governments' stances versus public opinion on the Israel-Palestine conflict
11:00 Blacklivesmatter: a semantic analysis on victimization and majority member activism
11:05 Activism or Alarmism: mapping Climate Change discourse in social networks
11:10 Study abroad: push and pull factors investigated through social networks
11:15 Wall-E: ethical attitudes towards AI in dfferent countries
11:20 Conclusions
11:25 Event in memory of Giulia Cecchettin, with the Rector and many authorities, right outside the hall room
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Le17 - Mon Nov 27, 2023 Lab #1 scraping data from Reddit and TikTok by Sina Tavakoli.
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Le18 - Fri Dec 1, 2023 Lab #2 building a semantic networks from textual data.
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Le19 - Mon Dec 4, 2023 Lab #3 network visualisation in Python by Lejla Dzanko
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Le20 - Mon Dec 11, 2023 Lab #4 network visualisation in Gephi by Lejla Dzanko
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Le15 - Mon Nov 20, 2023 Semantic networks; Data collection: Reddit and TikTok; Data preprocessing and SpaCy; Building the semantic network; the role of TF-IDF; Topic detection; A comparison between InfoMap and Louvain.
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Le21 - Fri Dec 15, 2023 The non-negative matrix factorization approach; generalized Kullback-Leibler divergence metric; Latent Dirichlet allocation: statistical model; Variational auto-encoders and the ELBO function; VAE for topic detection: NVDM, ProdLDA, DirVAE, NFTM, and NBVAE mnodels; The trasnformer architecture: BERT, BERTA, GPT-2, and GPT-3 models.
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Le22 - Mon Dec 18, 2023 BERTopic model and its performance; Sentiment analysis: an overview; LIWC categories; BERTAgent; Using sentiment analysis; Student's t-test and Cohen's d-value; Applications of PLMP; Wrap-up on topic detection.
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Le23 - Fri Dec 22, 2023 Homophily and related concepts: Selective exposure, Polarization, Ego Chamber, Filter bubble; Degree homophily or assortativity; the correlation matrix; Nearest neighbour degree function and its exponent; Structural disassortativity; Structural and natural cutoffs; Random rewiring; Network robustness; Robustness of scale-free networks; Attack tolerance; Robustness optimization; An application example.
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Le24 - Mon Jan 8, 2024 Feedback to projects/interdisciplinary projects.
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