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  1. Book ; Online: Dual Algorithmic Reasoning

    Numeroso, Danilo / Bacciu, Davide / Veličković, Petar

    2023  

    Abstract: Neural Algorithmic Reasoning is an emerging area of machine learning which seeks to infuse algorithmic computation in neural networks, typically by training neural models to approximate steps of classical algorithms. In this context, much of the current ... ...

    Abstract Neural Algorithmic Reasoning is an emerging area of machine learning which seeks to infuse algorithmic computation in neural networks, typically by training neural models to approximate steps of classical algorithms. In this context, much of the current work has focused on learning reachability and shortest path graph algorithms, showing that joint learning on similar algorithms is beneficial for generalisation. However, when targeting more complex problems, such similar algorithms become more difficult to find. Here, we propose to learn algorithms by exploiting duality of the underlying algorithmic problem. Many algorithms solve optimisation problems. We demonstrate that simultaneously learning the dual definition of these optimisation problems in algorithmic learning allows for better learning and qualitatively better solutions. Specifically, we exploit the max-flow min-cut theorem to simultaneously learn these two algorithms over synthetically generated graphs, demonstrating the effectiveness of the proposed approach. We then validate the real-world utility of our dual algorithmic reasoner by deploying it on a challenging brain vessel classification task, which likely depends on the vessels' flow properties. We demonstrate a clear performance gain when using our model within such a context, and empirically show that learning the max-flow and min-cut algorithms together is critical for achieving such a result.

    Comment: To appear at ICLR 2023. 16 pages, 9 figures
    Keywords Computer Science - Machine Learning ; Computer Science - Data Structures and Algorithms
    Subject code 006 ; 004
    Publishing date 2023-02-09
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Book ; Online: Neural Algorithmic Reasoning for Combinatorial Optimisation

    Georgiev, Dobrik / Numeroso, Danilo / Bacciu, Davide / Liò, Pietro

    2023  

    Abstract: Solving NP-hard/complete combinatorial problems with neural networks is a challenging research area that aims to surpass classical approximate algorithms. The long-term objective is to outperform hand-designed heuristics for NP-hard/complete problems by ... ...

    Abstract Solving NP-hard/complete combinatorial problems with neural networks is a challenging research area that aims to surpass classical approximate algorithms. The long-term objective is to outperform hand-designed heuristics for NP-hard/complete problems by learning to generate superior solutions solely from training data. Current neural-based methods for solving CO problems often overlook the inherent "algorithmic" nature of the problems. In contrast, heuristics designed for CO problems, e.g. TSP, frequently leverage well-established algorithms, such as those for finding the minimum spanning tree. In this paper, we propose leveraging recent advancements in neural algorithmic reasoning to improve the learning of CO problems. Specifically, we suggest pre-training our neural model on relevant algorithms before training it on CO instances. Our results demonstrate that by using this learning setup, we achieve superior performance compared to non-algorithmically informed deep learning models.
    Keywords Computer Science - Neural and Evolutionary Computing ; Computer Science - Machine Learning
    Subject code 006
    Publishing date 2023-05-18
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Book ; Online: Tensor Decompositions in Deep Learning

    Bacciu, Davide / Mandic, Danilo P.

    2020  

    Abstract: The paper surveys the topic of tensor decompositions in modern machine learning applications. It focuses on three active research topics of significant relevance for the community. After a brief review of consolidated works on multi-way data analysis, we ...

    Abstract The paper surveys the topic of tensor decompositions in modern machine learning applications. It focuses on three active research topics of significant relevance for the community. After a brief review of consolidated works on multi-way data analysis, we consider the use of tensor decompositions in compressing the parameter space of deep learning models. Lastly, we discuss how tensor methods can be leveraged to yield richer adaptive representations of complex data, including structured information. The paper concludes with a discussion on interesting open research challenges.
    Keywords Computer Science - Machine Learning ; Statistics - Machine Learning
    Publishing date 2020-02-26
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Early fitting in cochlear implant surgery: preliminary results.

    Soncini, Arianna / Franzini, Sebastiano / Di Marco, Francesca / Riccardi, Pasquale / Bacciu, Andrea / Pasanisi, Enrico / Di Lella, Filippo

    European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery

    2023  Volume 281, Issue 1, Page(s) 61–66

    Abstract: ... impedance values only in the short term but the differences were not statistically significant (p > 0.05 ... sessions, and the difference was statistically significant (p < 0.05). The mean PTA was lower in the early ... fitting group but the difference was not statistically significant (p < 0.05).: Conclusions: Early ...

    Abstract Purpose: Cochlear implants are usually activated 3-5 weeks after surgery; to date, no universal protocol exists regarding switch on and fitting of these devices. The aim of the study was to assess safety and functional results of activation and fitting of cochlear implant within 24 h following surgery.
    Methods: In this retrospective case-control study, 15 adult patients who underwent cochlear implant surgery, for a total of 20 cochlear implant procedures were analyzed. In particular, clinical safety and feasibility were investigated by examinating patients at activation and at each follow-up. Values of electrodes' impedance and most comfortable loudness (MCL) were analyzed from the time of surgery to 12 months after activation. Free-field pure tone average (PTA) was also recorded.
    Results: No major or minor complications were reported and all patients could perform the early fitting. Activation modality influenced impedance values only in the short term but the differences were not statistically significant (p > 0.05). Mean MCL values in the early fitting group were lower than MCL of the late fitting in all follow-up sessions, and the difference was statistically significant (p < 0.05). The mean PTA was lower in the early fitting group but the difference was not statistically significant (p < 0.05).
    Conclusions: Early fitting of cochlear implants is safe, allows for an early rehabilitation and can have possible beneficial effects on stimulation levels and dynamic range.
    MeSH term(s) Adult ; Humans ; Cochlear Implants ; Retrospective Studies ; Case-Control Studies ; Cochlear Implantation/methods ; Electric Impedance
    Language English
    Publishing date 2023-07-07
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1017359-6
    ISSN 1434-4726 ; 0937-4477
    ISSN (online) 1434-4726
    ISSN 0937-4477
    DOI 10.1007/s00405-023-08076-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Book ; Online: Renormalized Graph Neural Networks

    Caso, Francesco / Trappolini, Giovanni / Bacciu, Andrea / Liò, Pietro / Silvestri, Fabrizio

    2023  

    Abstract: Graph Neural Networks (GNNs) have become essential for studying complex data, particularly when represented as graphs. Their value is underpinned by their ability to reflect the intricacies of numerous areas, ranging from social to biological networks. ... ...

    Abstract Graph Neural Networks (GNNs) have become essential for studying complex data, particularly when represented as graphs. Their value is underpinned by their ability to reflect the intricacies of numerous areas, ranging from social to biological networks. GNNs can grapple with non-linear behaviors, emerging patterns, and complex connections; these are also typical characteristics of complex systems. The renormalization group (RG) theory has emerged as the language for studying complex systems. It is recognized as the preferred lens through which to study complex systems, offering a framework that can untangle their intricate dynamics. Despite the clear benefits of integrating RG theory with GNNs, no existing methods have ventured into this promising territory. This paper proposes a new approach that applies RG theory to devise a novel graph rewiring to improve GNNs' performance on graph-related tasks. We support our proposal with extensive experiments on standard benchmarks and baselines. The results demonstrate the effectiveness of our method and its potential to remedy the current limitations of GNNs. Finally, this paper marks the beginning of a new research direction. This path combines the theoretical foundations of RG, the magnifying glass of complex systems, with the structural capabilities of GNNs. By doing so, we aim to enhance the potential of GNNs in modeling and unraveling the complexities inherent in diverse systems.
    Keywords Computer Science - Machine Learning ; Physics - Data Analysis ; Statistics and Probability
    Subject code 006
    Publishing date 2023-06-01
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Book ; Online: Learning heuristics for A*

    Numeroso, Danilo / Bacciu, Davide / Veličković, Petar

    2022  

    Abstract: Path finding in graphs is one of the most studied classes of problems in computer science. In this context, search algorithms are often extended with heuristics for a more efficient search of target nodes. In this work we combine recent advancements in ... ...

    Abstract Path finding in graphs is one of the most studied classes of problems in computer science. In this context, search algorithms are often extended with heuristics for a more efficient search of target nodes. In this work we combine recent advancements in Neural Algorithmic Reasoning to learn efficient heuristic functions for path finding problems on graphs. At training time, we exploit multi-task learning to learn jointly the Dijkstra's algorithm and a consistent heuristic function for the A* search algorithm. At inference time, we plug our learnt heuristics into the A* algorithm. Results show that running A* over the learnt heuristics value can greatly speed up target node searching compared to Dijkstra, while still finding minimal-cost paths.

    Comment: 7 pages, 2 figures. To appear at the ICLR 2022 GroundedML Workshop
    Keywords Computer Science - Artificial Intelligence ; Computer Science - Machine Learning
    Publishing date 2022-04-11
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Reconstruction of Conchal Defects after Chemically Assisted Dissection of Squamous Cell Carcinoma

    Fabio Piazza / Annamaria Iole Palmeri / Andrea Bacciu / Giuseppe Spriano / Giuseppe Mercante

    Journal of Otorhinolaryngology, Hearing and Balance Medicine, Vol 4, Iss 2, p

    2023  Volume 10

    Abstract: Background: En block resection of squamous cell carcinoma (SCC) of the concha represents a reconstruction challenge, due to the complex topography and difficult access. Objective: The objective of the present paper is to describe the chemically assisted ... ...

    Abstract Background: En block resection of squamous cell carcinoma (SCC) of the concha represents a reconstruction challenge, due to the complex topography and difficult access. Objective: The objective of the present paper is to describe the chemically assisted dissection (CADISS) of SCC originating in the auricular concha and the following reconstruction of the conchal cavity with a post-auricular island flap (PIF), taking care to minimize injury to the donor site. Methods: Twenty-six patients having a diagnosis of SCC of the auricular concha were included in the study. ‘En bloc’ removal of the tumor was accomplished, leaving the adjacent conchal cartilage attached to the tumor and using the CADISS technique to preserve the deep perichondrium. A PIF was used to repair the auricular conchal defect. Results: Flaps were normal at 10 days and at 1-month follow-up. No tumor recurrence was observed. No complications were observed. According to the SCAR scale, good aesthetic outcomes were achieved in all cases, both at the auricular concha and at the donor site. Conclusion: CADISS facilitates the complete removal of the tumor with the preservation of the surrounding normal tissues. A post-auricular island flap can be easily pulled through a post-auricular tunnel to repair the defect and the donor site can be closed primarily.
    Keywords squamous cell carcinoma ; auricular conchal defect ; post-auricular island flap ; chemically assisted dissection ; Internal medicine ; RC31-1245
    Subject code 616
    Language English
    Publishing date 2023-09-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: A Deep Classifier for Upper-Limbs Motor Anticipation Tasks in an Online BCI Setting

    Andrea Valenti / Michele Barsotti / Davide Bacciu / Luca Ascari

    Bioengineering, Vol 8, Iss 2, p

    2021  Volume 21

    Abstract: Decoding motor intentions from non-invasive brain activity monitoring is one of the most challenging aspects in the Brain Computer Interface (BCI) field. This is especially true in online settings, where classification must be performed in real-time, ... ...

    Abstract Decoding motor intentions from non-invasive brain activity monitoring is one of the most challenging aspects in the Brain Computer Interface (BCI) field. This is especially true in online settings, where classification must be performed in real-time, contextually with the user’s movements. In this work, we use a topology-preserving input representation, which is fed to a novel combination of 3D-convolutional and recurrent deep neural networks, capable of performing multi-class continual classification of subjects’ movement intentions. Our model is able to achieve a higher accuracy than a related state-of-the-art model from literature, despite being trained in a much more restrictive setting and using only a simple form of input signal preprocessing. The results suggest that deep learning models are well suited for deployment in challenging real-time BCI applications such as movement intention recognition.
    Keywords deep learning ; brain–computer interfaces ; artificial neural networks ; Technology ; T ; Biology (General) ; QH301-705.5
    Subject code 004
    Language English
    Publishing date 2021-02-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Occlusion-Based Explanations in Deep Recurrent Models for Biomedical Signals

    Michele Resta / Anna Monreale / Davide Bacciu

    Entropy, Vol 23, Iss 1064, p

    2021  Volume 1064

    Abstract: The biomedical field is characterized by an ever-increasing production of sequential data, which often come in the form of biosignals capturing the time-evolution of physiological processes, such as blood pressure and brain activity. This has motivated a ...

    Abstract The biomedical field is characterized by an ever-increasing production of sequential data, which often come in the form of biosignals capturing the time-evolution of physiological processes, such as blood pressure and brain activity. This has motivated a large body of research dealing with the development of machine learning techniques for the predictive analysis of such biosignals. Unfortunately, in high-stakes decision making, such as clinical diagnosis, the opacity of machine learning models becomes a crucial aspect to be addressed in order to increase the trust and adoption of AI technology. In this paper, we propose a model agnostic explanation method, based on occlusion, that enables the learning of the input’s influence on the model predictions. We specifically target problems involving the predictive analysis of time-series data and the models that are typically used to deal with data of such nature, i.e., recurrent neural networks. Our approach is able to provide two different kinds of explanations: one suitable for technical experts, who need to verify the quality and correctness of machine learning models, and one suited to physicians, who need to understand the rationale underlying the prediction to make aware decisions. A wide experimentation on different physiological data demonstrates the effectiveness of our approach both in classification and regression tasks.
    Keywords interpretability ; occlusion ; recurrent networks ; biomedical signals ; Science ; Q ; Astrophysics ; QB460-466 ; Physics ; QC1-999
    Subject code 006
    Language English
    Publishing date 2021-08-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Contrasting patterns and interpretations between a fire spread simulator and a machine learning model when mapping burn probabilities: A case study for Mediterranean areas

    Costa-Saura, J.M. / Spano, D. / Sirca, C. / Bacciu, V.

    Environmental Modelling and Software. 2023 May, v. 163 p.105685-

    2023  

    Abstract: Two main approaches are commonly used to map fire-prone areas when designing firefighting and prevention campaigns: fire spread simulators and machine learning models. Despite they used mainly the same environmental variables, they differ in handling ... ...

    Abstract Two main approaches are commonly used to map fire-prone areas when designing firefighting and prevention campaigns: fire spread simulators and machine learning models. Despite they used mainly the same environmental variables, they differ in handling them. Thus, it is worth assessing differences in results and interpretations for supporting reliable decision-making process. Burn probabilities (BP) were calculated in Southern Italy using FlamMap and the Random Forest algorithm. Results showed contrasting spatial patterns, with Random Forest projecting more smoothed results than Flammap, which showed medium-high BP values only across some locations. In addition, BP from FlamMap and Random Forest differ across fuel types and environmental conditions. Results suggest that decisions based on fire simulators might be more tightly linked with actions preventing fire spread. In contrast, those based on machine learning might be more linked with fire occurrence elements not necessarily related to spreading, e.g., socioeconomic causes.
    Keywords algorithms ; case studies ; computer software ; decision making ; fire fighting ; fire spread ; fuels ; Italy ; Wildfire simulators ; Burn probability ; Fire occurrence ; Fire likelihood ; Fire susceptibility ; Wildfire management
    Language English
    Dates of publication 2023-05
    Publishing place Elsevier Ltd
    Document type Article ; Online
    ISSN 1364-8152
    DOI 10.1016/j.envsoft.2023.105685
    Database NAL-Catalogue (AGRICOLA)

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