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Università della Svizzera italiana

Detecting Alzheimer’s disease (AD) : from the asymptomatic stages of healthy adults with AD genetic disposition to late stages of severe neurocognitive impairment

Ibnidris, Aliaa ; Albanese, Emiliano (Dir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021BIOMED001.

Background: Dementia is a syndrome characterized by progressive cognitive impairment, psychological and behavioural symptoms, and functional deficits. It is one of the leading causes of disability worldwide; its impact and the associated costs are enormous. Consequently, dementia is a global public health priority, and so is Alzheimer’s disease (AD), the most common cause of dementia in late...

Università della Svizzera italiana

Learning dynamical systems using dynamical systems : the reservoir computing approach

Verzelli, Pietro ; Alippi, Cesare (Dir.) ; Livi, Lorenzo (Codir.)

Thèse de doctorat : Università della Svizzera italiana, 2022 ; 2022INF001.

Dynamical systems have been used to describe a vast range of phenomena, including physical sciences, biology, neurosciences, and economics just to name a few. The development of a mathematical theory for dynamical systems allowed researchers to create precise models of many phenomena, predicting their behaviors with great accuracy. For many challenges of dynamical systems, highly accurate...

Università della Svizzera italiana

Graph neural networks : operators and architectures

Grattarola, Daniele ; Alippi, Cesare (Dir.) ; Livi, Lorenzo (Codir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021INFO014.

This thesis explores the field of graph neural networks, a class of deep learning models designed to learn representations of graphs. We organise the work into two parts. In the first part, we focus on the essential building blocks of graph neural networks. We present three novel operators for learning graph representations: one graph convolutional layer and two methods for pooling. We put...

Università della Svizzera italiana

Multigrid methods for fractional diffusion equations

Trotti, Ken ; Krause, Rolf (Dir.) ; Donatelli, Marco (Codir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021INFO013.

Recent years have seen the rapid growth in interest towards fractional calculus. Fractional calculus plays an important role in modelling anomalous diffusion phenomena, however closed-form analytical solutions of such equations are rarely available, hence numerical estimates are needed. In this thesis we consider various fractional diffusion equations (FDEs), where different fractional ...

Università della Svizzera italiana

Mining code change patterns to aid software development

Fengcai, Wen ; Bavota, Gabriele (Dir.) ; Lanza, Michele (Codir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021INFO012.

Mining Software Repositories (MSR) has become a complete and mature research field, also due to the increasing number of open source projects publicly available. Repository hosting services such as GitHub provide unprecedented access to millions of events generated during development activities (e.g., code commits, pull requests), that can be mined and analyzed to extract new pieces of...

Università della Svizzera italiana

Sensor-based recognition of engagement during work and learning activities

Di Lascio, Elena ; Santini, Silvia (Dir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021INFO011.

Personal computing systems like e.g., laptop, smartphone, and smartwatches are nowadays ubiquitous in people's everyday life. People use such systems not only for communicating or searching for information, but also as digital companions, able to track and support their daily activities such as sleep, food intake, physical exercise and even work. Sensors embedded in personal computing systems...

Università della Svizzera italiana

Agents in superposition

Baumann, Veronika ; Brukner, Caslav (Dir.) ; Wolf, Stefan (Codir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021INFO010.

The idea of agents in superposition is central to both encapsulated observers, i.e. Wigner’s-friend-type experiments, and correlations without definite causal order. An agent might be regarded as a thinking or computing entity that is able to perform operations on (other) quantum systems. In case of Wigner’s-friend setups, an agent’s ability to make predictions about other agents...

Università della Svizzera italiana

Text mining for online mental health state and personality assessment

Ríssola, Esteban A. ; Crestani, Fabio (Dir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021INFO009.

Advances on psycho-linguistics have evidenced that the ways in which people use words could act as a reliable source to assess a wide array of behaviours. Language use acts as an indicator of the individuals’ current mental state, personality and even personal values. In this thesis, we focus on language analysis to study two closely related processes which encompass integral components of...

Università della Svizzera italiana

Scalable algorithms for high-dimensional graphical lasso and function approximation

Eftekhari, Aryan ; Schenk, Olaf (Dir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021INFO008.

Fundamental tasks in multivariate and numerical analysis, such as sparse precision matrix estimation via graphical lasso and function approximation, are formulated in ever-increasing dimensions. Consequently, this results in a significant increase in the computational demand that quickly renders standard solution methods intractable. With this motivation, we present two scalable algorithms that...

Università della Svizzera italiana

Node-level performance modeling of sparse factorization solver

Janalík, Radim ; Schenk, Olaf (Dir.)

Thèse de doctorat : Università della Svizzera italiana, 2021 ; 2021INFO006.

Solving large sparse linear systems is at the heart of many application problems arising from scientific and engineering problems. These systems are often solved by direct factorization solvers, especially when the system needs to be solved for multiple right-hand sides or when a high numerical precision is required. Direct solvers are based on matrix factorization, which is then followed by...