在过去的几年中，关于分类，检测和分割问题的3D学习领域取得了重大进展。现有的绝大多数研究都集中在规范的封闭式条件上，忽略了现实世界的内在开放性。这限制了需要管理新颖和未知信号的自主系统的能力。在这种情况下，利用3D数据可以是有价值的资产，因为它传达了有关感应物体和场景几何形状的丰富信息。本文提供了关于开放式3D学习的首次广泛研究。我们介绍了一种新颖的测试床，其设置在类别语义转移方面的难度增加，并且涵盖了内域（合成之间）和跨域（合成对真实）场景。此外，我们研究了相关的分布情况，并开放了2D文献，以了解其最新方法是否以及如何在3D数据上有效。我们广泛的基准测试在同一连贯的图片中定位了几种算法，从而揭示了它们的优势和局限性。我们的分析结果可能是未来量身定制的开放式3D模型的可靠立足点。

语义新颖性检测旨在发现测试数据中未知类别。此任务在安全至关重要的应用中特别相关，例如自动驾驶或医疗保健，在部署时间识别未知物体并相应地向用户发出警告至关重要。尽管深度学习研究取得了令人印象深刻的进步，但现有模型仍然需要在已知类别上进行填充阶段才能识别未知类别。当隐私规则限制数据访问或严格的内存和计算约束（例如边缘计算）时，这可能是令人难以置信的。我们声称，量身定制的表示策略可能是有效，有效的语义新颖性检测的正确解决方案。除了对此任务的最新方法进行最新的方法外，我们还提出了一种基于关系推理的新表示学习范式。它着重于学习如何衡量语义相似性而不是识别已知类别。我们的实验表明，这些知识可直接传输到各种场景，并且可以用作插件模块，以将封闭设置的识别模型转换为可靠的开放式开放集。

对于任何有价值的自治分子，知识不能仅限于制造商注入的有价值的自治药物而言，进化的能力都是基本的。例如，考虑家庭助理机器人：要求时它应该能够逐步学习新对象类别，也应该在不同的环境（房间）和姿势（手持/在地板上/上方的家具上方）中识别相同的对象，同时拒绝未知的。尽管它很重要，但这种情况才开始引起对机器人社区的兴趣，并且相关研究仍处于起步阶段，现有的实验测试床位，但没有量身定制的方法。通过这项工作，我们提出了第一种学习方法，该方法通过利用单个对比目标来立即涉及所有前面提到的挑战。我们展示了它如何学习功能空间非常适合逐步包括新类，并能够捕获在各种视觉域中概括的知识。我们的方法赋予了每个学习情节的量身定制的有效停止标准，并利用了一个自进度的阈值策略，该策略为分类器提供了可靠的拒绝选项。这两种新颖的贡献均基于对数据统计数据的观察，不需要手动调整。广泛的实验分析证实了拟议方法在建立新的最新技术方面的有效性。该代码可在https://github.com/francescocappio/contrastive_open_world上找到。

深度检测方法在受控条件下具有强大的功能，但是当在看不见的域上使用源模型时，显得脆弱和失败。域适应性的大多数现有作品简化了设置并共同访问大型源数据集和相当大的目标样本。但是，在许多实际情况下，这种情况是不现实的，例如从社交媒体监视图像提要时：只有预审计的源模型可用，并且用户上传的每个目标图像都属于在培训期间未预见的其他域。我们通过提出能够利用预训练的源模型并通过仅使用测试时看到的一个目标样本来实现无监督适应的对象检测算法来解决这种具有挑战性的设置。我们的多任务架构包括一个自我监督的分支，我们利用单样本跨域发作为整个模型进行元模型，并准备测试条件。在部署时间，自我监督的任务是在任何传入的样本上迭代解决的，以对其进行单次调整。我们介绍了一个新的社交媒体图像源数据集，并提供了最新的跨域检测方法的彻底基准，该方法显示了我们方法的优势。

Continual Learning (CL) is a field dedicated to devise algorithms able to achieve lifelong learning. Overcoming the knowledge disruption of previously acquired concepts, a drawback affecting deep learning models and that goes by the name of catastrophic forgetting, is a hard challenge. Currently, deep learning methods can attain impressive results when the data modeled does not undergo a considerable distributional shift in subsequent learning sessions, but whenever we expose such systems to this incremental setting, performance drop very quickly. Overcoming this limitation is fundamental as it would allow us to build truly intelligent systems showing stability and plasticity. Secondly, it would allow us to overcome the onerous limitation of retraining these architectures from scratch with the new updated data. In this thesis, we tackle the problem from multiple directions. In a first study, we show that in rehearsal-based techniques (systems that use memory buffer), the quantity of data stored in the rehearsal buffer is a more important factor over the quality of the data. Secondly, we propose one of the early works of incremental learning on ViTs architectures, comparing functional, weight and attention regularization approaches and propose effective novel a novel asymmetric loss. At the end we conclude with a study on pretraining and how it affects the performance in Continual Learning, raising some questions about the effective progression of the field. We then conclude with some future directions and closing remarks.

Computational units in artificial neural networks follow a simplified model of biological neurons. In the biological model, the output signal of a neuron runs down the axon, splits following the many branches at its end, and passes identically to all the downward neurons of the network. Each of the downward neurons will use their copy of this signal as one of many inputs dendrites, integrate them all and fire an output, if above some threshold. In the artificial neural network, this translates to the fact that the nonlinear filtering of the signal is performed in the upward neuron, meaning that in practice the same activation is shared between all the downward neurons that use that signal as their input. Dendrites thus play a passive role. We propose a slightly more complex model for the biological neuron, where dendrites play an active role: the activation in the output of the upward neuron becomes optional, and instead the signals going through each dendrite undergo independent nonlinear filterings, before the linear combination. We implement this new model into a ReLU computational unit and discuss its biological plausibility. We compare this new computational unit with the standard one and describe it from a geometrical point of view. We provide a Keras implementation of this unit into fully connected and convolutional layers and estimate their FLOPs and weights change. We then use these layers in ResNet architectures on CIFAR-10, CIFAR-100, Imagenette, and Imagewoof, obtaining performance improvements over standard ResNets up to 1.73%. Finally, we prove a universal representation theorem for continuous functions on compact sets and show that this new unit has more representational power than its standard counterpart.

Detecting anomalous data within time series is a very relevant task in pattern recognition and machine learning, with many possible applications that range from disease prevention in medicine, e.g., detecting early alterations of the health status before it can clearly be defined as "illness" up to monitoring industrial plants. Regarding this latter application, detecting anomalies in an industrial plant's status firstly prevents serious damages that would require a long interruption of the production process. Secondly, it permits optimal scheduling of maintenance interventions by limiting them to urgent situations. At the same time, they typically follow a fixed prudential schedule according to which components are substituted well before the end of their expected lifetime. This paper describes a case study regarding the monitoring of the status of Laser-guided Vehicles (LGVs) batteries, on which we worked as our contribution to project SUPER (Supercomputing Unified Platform, Emilia Romagna) aimed at establishing and demonstrating a regional High-Performance Computing platform that is going to represent the main Italian supercomputing environment for both computing power and data volume.

Recent object detection models for infrared (IR) imagery are based upon deep neural networks (DNNs) and require large amounts of labeled training imagery. However, publicly-available datasets that can be used for such training are limited in their size and diversity. To address this problem, we explore cross-modal style transfer (CMST) to leverage large and diverse color imagery datasets so that they can be used to train DNN-based IR image based object detectors. We evaluate six contemporary stylization methods on four publicly-available IR datasets - the first comparison of its kind - and find that CMST is highly effective for DNN-based detectors. Surprisingly, we find that existing data-driven methods are outperformed by a simple grayscale stylization (an average of the color channels). Our analysis reveals that existing data-driven methods are either too simplistic or introduce significant artifacts into the imagery. To overcome these limitations, we propose meta-learning style transfer (MLST), which learns a stylization by composing and tuning well-behaved analytic functions. We find that MLST leads to more complex stylizations without introducing significant image artifacts and achieves the best overall detector performance on our benchmark datasets.

Objective: Accurate visual classification of bladder tissue during Trans-Urethral Resection of Bladder Tumor (TURBT) procedures is essential to improve early cancer diagnosis and treatment. During TURBT interventions, White Light Imaging (WLI) and Narrow Band Imaging (NBI) techniques are used for lesion detection. Each imaging technique provides diverse visual information that allows clinicians to identify and classify cancerous lesions. Computer vision methods that use both imaging techniques could improve endoscopic diagnosis. We address the challenge of tissue classification when annotations are available only in one domain, in our case WLI, and the endoscopic images correspond to an unpaired dataset, i.e. there is no exact equivalent for every image in both NBI and WLI domains. Method: We propose a semi-surprised Generative Adversarial Network (GAN)-based method composed of three main components: a teacher network trained on the labeled WLI data; a cycle-consistency GAN to perform unpaired image-to-image translation, and a multi-input student network. To ensure the quality of the synthetic images generated by the proposed GAN we perform a detailed quantitative, and qualitative analysis with the help of specialists. Conclusion: The overall average classification accuracy, precision, and recall obtained with the proposed method for tissue classification are 0.90, 0.88, and 0.89 respectively, while the same metrics obtained in the unlabeled domain (NBI) are 0.92, 0.64, and 0.94 respectively. The quality of the generated images is reliable enough to deceive specialists. Significance: This study shows the potential of using semi-supervised GAN-based classification to improve bladder tissue classification when annotations are limited in multi-domain data.

Neural image classifiers are known to undergo severe performance degradation when exposed to input that exhibits covariate-shift with respect to the training distribution. Successful hand-crafted augmentation pipelines aim at either approximating the expected test domain conditions or to perturb the features that are specific to the training environment. The development of effective pipelines is typically cumbersome, and produce transformations whose impact on the classifier performance are hard to understand and control. In this paper, we show that recent Text-to-Image (T2I) generators' ability to simulate image interventions via natural-language prompts can be leveraged to train more robust models, offering a more interpretable and controllable alternative to traditional augmentation methods. We find that a variety of prompting mechanisms are effective for producing synthetic training data sufficient to achieve state-of-the-art performance in widely-adopted domain-generalization benchmarks and reduce classifiers' dependency on spurious features. Our work suggests that further progress in T2I generation and a tighter integration with other research fields may represent a significant step towards the development of more robust machine learning systems.