Mar 232025
 

Introduction to Compositional Data Analysis and Modelling

Prof. Fabio Divino
Università del Molise & University of Jyväskylä

Abstract

This course introduces the fundamental concepts of compositional data analysis, including the algebraic structure of the simplex and its main properties. It will then cover the basic tools for analysis before presenting the main regression models:
(a) compositional data as a predictor;
(b) compositional data as a response variable;
(c) compositional data as both predictor and response.

All topics will be explored through hands-on lab sessions in R using real data and simulations.

Outline

  • Lecture 1: Introduction to Compositional Data Analysis. ALR, ILR, and CLR Transformations
  • Lecture 2: Descriptive Analysis in the Simplex. Introduction to Regression Models
  • Lecture 3: Regression Models with Compositional Data

Schedule

The course consists of a total of 6 hours, scheduled as follows:

  • March 17, 15:00-17:00 – Aula A
  • March 19, 11:00-13:00 – Aula A
  • March 21, 15:00-17:00 – Aula A

Exam

The final exam consists of a presentation on a specific topic covered in the course.

References

  • K. Gerald van den Boogaart & Raimon Tolosana-Delgado, Analyzing Compositional Data with R, Springer, 2013.
 Scritto da in 23 Marzo 2025  Senza categoria  Commenti disabilitati su PhD Course: Introduction to Compositional Data Analysis and Modelling
Mar 122025
 

Introduction to Algorithmic Fairness: Principles, Methods and Regulatory Perspectives

Dr. Erasmo Purificato
European Commission, Joint Research Centre (JRC), Italy

Abstract

The course provides a comprehensive introduction to algorithmic fairness, exploring key concepts such as definitions, bias characterisation and the potential sources of unfairness in machine learning models. Initially, we will thoroughly examine fairness criteria, bias detection metrics, and the limitation of fairness evaluation in binary scenarios. Then, we will analyse the emerging multiclass and multigroup approaches, and cover bias mitigation techniques and their practical trade-offs. Finally, the course will examine legal and ethical frameworks governing algorithmic fairness, with a focus on EU regulations such as the GDPR, DSA, and AI Act, as well as global policies.

Outline

  • Lecture 1: Foundation of Algorithmic Fairness
    • Why fairness matters in AI and ML
    • Defining fairness and bias
    • Potential causes of unfairness in ML
    • Fairness criteria
    • Conflicts between fairness goals
  • Lecture 2 – Measuring Bias and Fairness
    • Bias detection metrics
    • Challenges in binary scenarios
    • Extending fairness metrics to multiclass and multigroup scenarios
  • Lecture 3 – Mitigating Bias
    • Bias mitigation strategies
    • Choosing the right fairness intervention
    • Trade-offs and practical implementations
  • Lecture 4 – Legal and Ethical Frameworks for Fairness in AI
    • Overview of EU Regulations affecting AI and ML (i.e., GDPR, DSA and AI Act)
    • Fairness principles in EU Regulations
    • Fairness principles in global regulations
    • The future of algorithmic fairness and open research challenges

Schedule

The course will have a total duration of 10 hours, scheduled as follows:

  • May 21, 14:00-18:00 Aula II
  • May 22, 10:30-12:30 Aula F
  • May 22, 14:00-16:00 Aula F
  • May 23, 10:00-12:00 Aula F

Exam

The final exam consists either in a seminar presentation focusing on a specific topic studied during the course or in a test held on the last day of the course. The definitive format will be announced when the schedule is finalized. The course will be held in person. Please contact me if you are interested in joining.

References

The content of the course is based (but not limited to) the following articles:

  1. Simon Caton and Christian Haas. Fairness in Machine Learning: A Survey. ACM Comput. Surv. 56, 7, Article 166 (2024). https://dl.acm.org/doi/10.1145/3616865
  2. Corbett-Davies, Sam, Johann D. Gaebler, Hamed Nilforoshan, Ravi Shroff, and Sharad Goel. The measure and mismeasure of fairness. Journal of Machine Learning Research 24, no. 312 (2023). https://jmlr.org/papers/v24/22-1511.html
  3. Dana Pessach and Erez Shmueli. A Review on Fairness in Machine Learning. ACM Comput. Surv. 55, 3, Article 51 (2023). https://doi.org/10.1145/3494672
  4. Sahil Verma and Julia Rubin. Fairness definitions explained. In Proceedings of the International Workshop on Software Fairness (FairWare 2018). https://doi.org/10.1145/3194770.3194776
  5. Purificato, Erasmo, Ludovico Boratto, and Ernesto William De Luca. Toward a responsible fairness analysis: from binary to multiclass and multigroup assessment in graph neural network-based user modeling tasks. Minds and Machines 34, no. 3 (2024). https://doi.org/10.1007/s11023-024-09685-x
  6. Regulation (EU) 2016/679 of the European Parliament and of the Council of 27 April 2016 on the protection of natural persons with regard to the processing of personal data and on the free movement of such data, and repealing Directive 95/46/EC (General Data Protection Regulation),
    2016, OJ L119/1. http://data.europa.eu/eli/reg/2016/679/oj
  7. Regulation (EU) 2022/2065 of the European Parliament and of the Council of 19 October 2022 on a Single Market For Digital Services and amending Directive 2000/31/EC (Digital Services Act), 2022, OJ L277/1. http://data.europa.eu/eli/reg/2022/2065/oj
  8. Regulation (EU) 2024/1689 of the European Parliament and of the Council of 13 June 2024 laying down harmonised rules on artificial intelligence and amending Regulations (EC) No 300/2008, (EU) No 167/2013, (EU) No 168/2013, (EU) 2018/858, (EU) 2018/1139 and (EU) 2019/2144 and
    Directives 2014/90/EU, (EU) 2016/797 and (EU) 2020/1828 (Artificial Intelligence Act), 2024, http://data.europa.eu/eli/reg/2024/1689/oj
 Scritto da in 12 Marzo 2025  News, News, News, News  Commenti disabilitati su PhD Course: Introduction to Algorithmic Fairness
Gen 142025
 

MAIN PhD Seminars 2024

Date Speaker(s)
January, 15th Sandro Gabriele Tiddia
January, 29th Andrea Azzarelli
February, 12nd Valentino Artizzu
February, 26th Simone Pusceddu
March, 12nd Nicola Piras
March, 26th Sara Vergallo
Giorgia Nieddu
April, 9th Matteo Mocci
April, 23rd Michele Faedda

All the seminars at 13:00 in Aula Magna di Fisica.

 

Sandro Gabriele Tiddia: LLM Agents: Definitions and Real-World Applications

In this seminar, we explore the concept of ‘agents’ in artificial intelligence (AI), with a particular focus on the role of Large Language Models (LLMs) in powering these systems. The seminar begins by discussing a real-world application where LLMs are used to build a question-answering (QA) system, showing how LLMs can function as ‘agents’ within such a system. We then examine various definitions of ‘agent’ across AI subfields and consider how agents interact with their environment, make decisions, and pursue goals autonomously. Additionally, we revisit earlier works on agency in AI, reflecting on their original, more profound ideas, and connect them to recent developments and applications of LLM-powered agents. The seminar concludes by exploring experiments and use cases from recent literature, highlighting the capabilities and potential of LLM agents across different domains. The goal is to provide a clear introduction to the concept of LLM-powered agents, their role in AI systems, and how this concept has evolved from theoretical foundations to practical applications.

Andrea Azzarelli: Fractional Laplacian and ADMM for glyph extraction

In archaeology it is a common task to extract incisions or glyphs from a surface. This procedure is usually done manually and, therefore, it is prone to errors and it can be extremely time consuming. In this talk we present a variational model to automatically extract these incisions from a smooth surface. We provide a procedure to generate realistic synthetic data and we show the performances of the proposed method on this kind of data.

Valentino Artizzu: End-User Development for Extended Reality: Empowering Users to Create and Understand XR Environments

In this seminar we will see how to enable individuals without prior XR development experience to create and understand XR environments. It focuses on using End-User Development (EUD) techniques to allow users to design, build, and adapt XR systems. The research specifically explores methodologies and tools for non-programmers to construct XR environments. It examines how EUD can facilitate novice developers in comprehending existing VR environments for enhancement purposes. The study further investigates how EUD can empower domain experts to tailor these environments to meet diverse requirements. Additionally, it delves into how EUD can guide domain experts in configuring XR environments to support task learning and demonstration. The goal is to provide a clear overview of the topic using the experiences and the applications developed during the three years of a PhD career.

Nicola Piras: Global and local fit measures for latent class models and extensions

Latent class (LC) analysis is a powerful and flexible statistical tool for model-based clustering with categorical data. An important task in LC analysis is the choice of the number of clusters or classes. The choice of the number of classes is a selection model problem and usually Information Criteria are considered for this purpose. These are measures that weigh model fit (log-likelihood) and model complexity (based on the number of free parameters). The LC models formulation is subject to an assumption of conditional independence between the variables involved. Adherence to this assumption and the correct estimation of the parameters is central to evaluate how well the model fits to the data. While global selection and the goodness of fit is verified through Information Criteria, model conditions must also be checked. Specific statistics can be defined that allow to verify the local independence assumption. In the literature of LC analysis the statistics considered are the Bivariate residuals. The standard LC model can be modified to handle more complex data structures, and fit measures must be adapted to the new formulations. In this talk, after having briefly discussed the results in the standard formulation, I will also present the extension to the case in which data have a multilevel cross-classified structure. This structure is present when observations are simultaneously nested within two groups, for example, children nested within both schools and neighborhoods. An application is illustrated using an Italian dataset on the evaluation of students of their degree programmes, where degree programmes are nested in both universities and fields of study.

 Scritto da in 14 Gennaio 2025  Senza categoria  Commenti disabilitati su MAIN PhD Seminars 2025
Gen 102025
 

Interpretable and Explainable Machine Learning Models

Dr. Claudio Pomo
Politecnico di Bari

Abstract

The course focuses on methods for interpreting and explaining machine learning (ML) models, including inherently interpretable approaches and post-hoc explanation techniques. Key concepts of interpretability will be introduced, alongside the analysis of interpretable models and the application of explanation methods for complex models. The course critically evaluates existing techniques in terms of fidelity, stability, fairness, and practical utility, while addressing open challenges and future perspectives.

Schedule

The course will have a total duration of 10 hours, scheduled as follows:

  • March 20, 15:00-17:30 Aula II
  • March 21, 10:00-12:30 Aula F
  • March 24, 15:00-17:30 Aula II
  • March 25, 10:00-12:30 Sala Riunioni II piano

Exam

The final exam consists of a project analyzing a case study using the techniques and tools acquired during the course. The course will be held in person. Please contact me if you are interested in joining.

References

  1. Lundberg, S. M., and Lee, S.-I. A unified approach to interpreting model predictions. Advances in Neural Information Processing Systems, 2017.
  2. Ribeiro, M. T., Singh, S., and Guestrin, C. Why should I trust you? Explaining the predictions of any classifier. Proceedings of the ACM SIGKDD, 2016.
  3. Molnar, C.. Interpretable Machine Learning: A Guide for Making Black Box Models Explainable. 2nd edition, 2022.
  4. Doshi-Velez, F., and Kim, B. Towards a rigorous science of interpretable machine learning. arXiv preprint, 2017.
  5. Agarwal, C., Krishna, S., Saxena, E., Pawelczyk, M., Johnson, N., Puri, I., … & Lakkaraju, H. Openxai: Towards a transparent evaluation of model explanations. Advances in Neural Information Processing Systems, 2022
 Scritto da in 10 Gennaio 2025  Senza categoria  Commenti disabilitati su PhD Course: Interpretable and Explainable Machine Learning Models
Ott 242024
 

Introduction to algebraic logic

Dr. Nicolò Zamperlin
Università degli Studi di Cagliari

Abstract

The course is an introduction to the theory of algebraizability of Blok and Pigozzi. Through an analytic study of the first chapters of Font’s handbook on abstract algebraic logic we will first introduce the elementary notions of universal algebra needed for linking together logic and algebra (closure operators and their lattices, varieties, quasivarieties and equational consequences), then building upon these notions we will consider the case of implicative logics and their algebraic properties, introducing the technique of completeness through the Lindenbaum-Tarski process. Finally we generalize these notions to the class of algebraizable logics (with a glimpse to the larger Leibniz heirarchy), with the ultimate goal of proving the isomorphism theorem and the transfer for the deduction theorem.

Schedule

The course will have a duration of 20 hours, scheduled as follows:ˆ

  • November 7, aula B, h. 15-17
  • November 14, aula A, h. 15-17
  • November 22, aula II, h. 9:30-11:30
  • November 29, aula II, h. 9:30-11:30
  • December 2, aula II, h. 9:30-11
  • December 6, aula II, h. 9:30-11:30
  • December 12, aula B, h. 15-17
  • January 15, aula B, h. 10-12
  • January 20, aula B, h. 15-17
  • February 3, aula B, h. 10-12

Exam

The final exam consists in a seminar presentation. The course will be held in person. Please contact me if you are interested in joining the course

References

  1. Bergman, C., Universal Algebra: Fundamentals and Selected Topics, Chapman & Hall Pure and Applied Mathematics, Chapman and Hall/CRC, 2011.
  2. Blok, W., and Pigozzi, D., Algebraizable logics, vol. 396 of Memoirs of the American Mathematical Society, A.M.S., 1989.
  3. Burris, S., and Sankappanavar, H.P., A course in Universal Algebra, freely available online: https://www.math.uwaterloo.ca/snburris/htdocs/ualg.html, 2012 update.
  4. Czelakowski, J., Protoalgebraic logics, vol. 10 of Trends in Logic: Studia Logica Library, Kluwer Academic Publishers, Dordrecht, 2001.
  5. Font, J.M., Abstract Algebraic Logic: An Introductory Textbook, College Publications, 2016
 Scritto da in 24 Ottobre 2024  Senza categoria  Commenti disabilitati su PhD Course: Introduction to algebraic logic
Set 232024
 

Conic Programming: Theory and applications

Prof. Benedetto Manca
Università degli Studi di Cagliari

Abstract

The course covers the theory of conic programming, starting from the simplest case of linear programming and introducing conic quadratic and semi-definite programming. The first part of the course will introduce the theoretical backgrounds needed to define the concept of conic programming. In the second part the case of conic quadratic and semi-definite programming will be addressed together with some applications.

Outline

  • From Linear to Conic Programming
  • Conic Quadratic Programming
  • The quadratic formulation of the Distance Geometry Problem
  • Semi-definite Programming
  • The semi-definite relaxation of the Distance Geometry Problem
  • Diagonally dominant matrices and positive semi-definite matrices
  • The ellipsoidal separation problem

Schedule

The course consists in 10 hours, two lectures per week. Details will be specified on the occasion of the first lecture, which will be given on October 3, 2024 at 2:30 p.m. in room B of the Department of Mathematics and Computer Science.

Exam

The final exam consists in a presentation on a specific application of conic programming (conic quadratic or semi-definite).

References

  1. Ben-Tal, Aharon, and Arkadi Nemirovski. Lectures on modern convex optimization: analysis, algorithms, and engineering applications. Society for industrial and applied mathematics, 2001.
  2. Liberti, Leo. Distance geometry and data science. Top 28.2 (2020): 271-339
  3. Astorino, Annabella, et al. Ellipsoidal classification via semidefinite programming. Operations Research Letters 51.2 (2023): 197-203.
 Scritto da in 23 Settembre 2024  Senza categoria  Commenti disabilitati su PhD Course: Conic Programming: Theory and applications
Set 122024
 

Introduction to Kähler Geometry

Prof. Roberto Mossa, Prof. Giovanni Placini
Università degli Studi di Cagliari

Abstract

This introductory course covers some of the fundamental concepts of Kähler geometry, with particular attention to almost complex and complex manifolds, the properties of Hermitian metrics, and Kähler metrics. Starting from the basics of differential geometry, we will explore the structure of almost complex and complex manifolds. Subsequently, we will delve into the properties of Hermitian metrics, focusing on the definition and characteristics that define Kähler metrics, which play a key role in integrating the complex structure with the Riemannian one. Through concrete examples and applications, students will gain a deep understanding of these concepts, preparing them for advanced studies in Kähler geometry.

Schedule

The course consists of 32 hours divided into 16 lectures. This is the schedule of the lectures:

  • Martedì 14 Gennaio 15-17 Aula III (Giovanni Placini)
  • Giovedì 16 Gennaio 11-13 Aula III (Giovanni Placini)
  • Martedì 21 Gennaio 11-13 Aula III (Giovanni Placini)
  • Giovedì 23 Gennaio 11-13 Aula III (Giovanni Placini)
  • Martedì 28 Gennaio 11-13 Aula III (Giovanni Placini)
  • Giovedì 30 Gennaio 11-13 Aula III (Roberto Mossa)
  • Martedì 4 Febbraio 11-13 Aula III (Roberto Mossa)
  • Giovedì 6 Febbraio 11-13 Aula III (Roberto Mossa)
  • Martedì 11 Febbraio 11-13 Aula III (Roberto Mossa)
  • Giovedì 13 Febbraio 11-13 Aula III (Roberto Mossa)
  • Lunedì 17 Febbraio 11-13 Aula III (Roberto Mossa)
  • Giovedì 20 marzo 11-13 Aula F (Roberto Mossa)
  • Giovedì 27 marzo 11-13 Aula F (Roberto Mossa)
  • Giovedì 3 aprile 11-13 Aula F (Giovanni Placini)
  • Martedì 8 aprile 11-13 Aula F (Giovanni Placini)
  • Giovedì 10 aprile 11-13 Aula F (Giovanni Placini)

Exam

The final exam consists in a seminar on a topic building on the content of the course. The topic for the final exam may be proposed by the students themselves or chosen from a list provided at the end of the lectures.

 Scritto da in 12 Settembre 2024  Senza categoria  Commenti disabilitati su PhD Course: Introduction to Kähler Geometry
Ago 212024
 

Numerical Analysis with Deep Neural Networks

Prof. Yuesheng Xu
Old Dominion University and Syracuse University, USA

Abstract

This four-talk lecture sequence aims to introduce numerical analysis with deep neural networks. Traditional function classes used in numerical analysis include polynomials, trigonometric polynomials, splines, finite elements, wavelets, and kernels. Deep neural networks were recently employed in numerical analysis as a class of approximation functions, demonstrating advantages over traditional function classes. These talks will cover the following topics:

  1. Deep neural network representation of a function
  2.  Optimization problems that learn a neural network
  3. Adaptive solutions of integral equations with deep neural networks
  4. Adaptive solutions of partial differential equations with deep neural networks.

Schedule

September 12nd, 9.30-11.30 Aula A
September 13nd, 9.30-11.30 Aula A

Lug 222024
 

QUBO and Quantum Annealing

Prof. Michele Marchesi
University of Cagliari and NetService spa

Abstract

The seminar, lasting about an hour, presents the problems of unconstrained binary quadratic optimization, where the variables assume binary values (0/1 or -1/1), and the function to be optimized is a quadratic form with real coefficients. It will discuss various real problems that can be represented as QUBO and how to incorporate constraints using penalty coefficients. Exact classical solvers, which can only be used for small problems due to the NP-complete complexity of QUBO problems, and the main heuristic solvers: Tabu Search and Simulated Annealing, will then be presented. Finally, the Quantum Annealing approach for solving this type of problem on specialized quantum computers will be presented.

Schedule

July 25th, 9:30-10:30 (Palazzo delle Scienze, Aula B)

 Scritto da in 22 Luglio 2024  Senza categoria  Commenti disabilitati su Seminar: QUBO and Quantum Annealing
Lug 032024
 

Research in Blockchain and Quantum Technologies

Dr. Ernestas Filatovas
Vilnius University, Lithuania

Abstract

Blockchain and Quantum technologies are among the most groundbreaking advancements, attracting significant attention from industry, government, and academia. This talk highlights the research advances of our “Blockchain and Quantum Technologies Group” in both fields. In the first part of the talk, we introduce Blockchain technology, covering its main concepts such as decentralization, consensus protocols, transaction flow, etc. These key concepts later are summarized within a layered structure. We then present our recent research, including a systematic review and empirical analysis of blockchain simulators, a multi-criteria decision-making (MCDM) framework for selecting consensus protocols, a data-driven classification of consensus protocols using machine learning, and an empirical analysis of wealth decentralization in blockchain networks. This part concludes with an introduction to our novel blockchain-based platform designed to enhance research reproducibility in machine learning. The second part of the talk shifts to Quantum Computing, beginning with an overview of the current state of this technology and its potential applications across various industries. We then highlight our recent achievements, such as the development of more efficient quantum circuits for integer division and the implementation of a quantum blockchain based on hypergraphs. The talk finishes with a presentation of our ongoing research, where we propose an improved quantum annealing method to scale vehicle routing problems.

Schedule

June 20th, 10:00-12:00 (Palazzo delle Scienze, Aula Magna Matematica)

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