由于技术成本的降低和卫星发射的增加，卫星图像变得越来越流行和更容易获得。除了提供仁慈的目的外，还可以出于恶意原因（例如错误信息）使用卫星数据。事实上，可以依靠一般图像编辑工具来轻松操纵卫星图像。此外，随着深层神经网络（DNN）的激增，可以生成属于各种领域的现实合成图像，与合成生成的卫星图像的扩散有关的其他威胁正在出现。在本文中，我们回顾了关于卫星图像的产生和操纵的最新技术（SOTA）。特别是，我们既关注从头开始的合成卫星图像的产生，又要通过图像转移技术对卫星图像进行语义操纵，包括从一种类型的传感器到另一种传感器获得的图像的转换。我们还描述了迄今已研究的法医检测技术，以对合成图像伪造进行分类和检测。虽然我们主要集中在法医技术上明确定制的，该技术是针对AI生成的合成内容物的检测，但我们还审查了一些用于一般剪接检测的方法，这些方法原则上也可以用于发现AI操纵图像

合成孔径雷达（SAR）图像是各种任务的有价值资产。在过去的几年里，许多网站以易于管理产品的形式免费提供它们，倾向于在S​​AR领域的广泛扩散和研究工作。这些机会的缺点是，这些图像可能会被恶意用户暴露于伪造和操纵，提高对他们的诚信和可信度的新担忧。到目前为止，多媒体取证文献提出了各种技术来定位自然照片中的操纵，但从未调查过SAR图像的完整性评估。此任务构成了新的挑战，因为SAR图像是由处理链完全不同于自然照片的图像。这意味着对于自然图像开发的许多取证方法不保证成功。在本文中，我们研究了SAR图像拼接定位问题的问题。我们的目标是本地化已经复制和粘贴了从另一个图像复制和粘贴的幅度SAR图像的区域，可能正在进行该过程中的某种编辑。为此，我们利用卷积神经网络（CNN）来提取在分析的输入的处理迹线中突出的指纹突出显示。然后，我们检查该指纹以产生二进制篡改掩模，指示拼接攻击下的像素区域。结果表明，我们提出的方法，针对SAR信号的性质量身定制，提供比为自然图像开发的最先进的法医工具更好的表现。

综合产生的内容的广泛扩散是一种需要紧急对策的严重威胁。合成含量的产生不限于多媒体数据，如视频，照片或音频序列，但涵盖了可以包括生物图像的显着大面积，例如西幕和微观图像。在本文中，我们专注于检测综合生成的西幕图像。生物医学文献在很大程度上探讨了西部污染图像，已经表明了如何通过目视检查或标准取证检测器轻松地伪造这些图像。为了克服缺乏公开可用的数据集，我们创建了一个包含超过14k原始的西幕图像和18K合成的Western-Blot图像的新数据集，由三种不同的最先进的生成方法产生。然后，我们调查不同的策略来检测合成的Western印迹，探索二进制分类方法以及单级探测器。在这两种情况下，我们从不利用培训阶段的合成纤维图像。所达到的结果表明，即使在这些科学图像的合成版本未优化利用检测器，综合生成的西幕图像也可以具有良好的精度。

We are witnessing a widespread adoption of artificial intelligence in healthcare. However, most of the advancements in deep learning (DL) in this area consider only unimodal data, neglecting other modalities. Their multimodal interpretation necessary for supporting diagnosis, prognosis and treatment decisions. In this work we present a deep architecture, explainable by design, which jointly learns modality reconstructions and sample classifications using tabular and imaging data. The explanation of the decision taken is computed by applying a latent shift that, simulates a counterfactual prediction revealing the features of each modality that contribute the most to the decision and a quantitative score indicating the modality importance. We validate our approach in the context of COVID-19 pandemic using the AIforCOVID dataset, which contains multimodal data for the early identification of patients at risk of severe outcome. The results show that the proposed method provides meaningful explanations without degrading the classification performance.

Human Activity Recognition (HAR) is one of the core research areas in mobile and wearable computing. With the application of deep learning (DL) techniques such as CNN, recognizing periodic or static activities (e.g, walking, lying, cycling, etc.) has become a well studied problem. What remains a major challenge though is the sporadic activity recognition (SAR) problem, where activities of interest tend to be non periodic, and occur less frequently when compared with the often large amount of irrelevant background activities. Recent works suggested that sequential DL models (such as LSTMs) have great potential for modeling nonperiodic behaviours, and in this paper we studied some LSTM training strategies for SAR. Specifically, we proposed two simple yet effective LSTM variants, namely delay model and inverse model, for two SAR scenarios (with and without time critical requirement). For time critical SAR, the delay model can effectively exploit predefined delay intervals (within tolerance) in form of contextual information for improved performance. For regular SAR task, the second proposed, inverse model can learn patterns from the time series in an inverse manner, which can be complementary to the forward model (i.e.,LSTM), and combining both can boost the performance. These two LSTM variants are very practical, and they can be deemed as training strategies without alteration of the LSTM fundamentals. We also studied some additional LSTM training strategies, which can further improve the accuracy. We evaluated our models on two SAR and one non-SAR datasets, and the promising results demonstrated the effectiveness of our approaches in HAR applications.

Testing Deep Learning (DL) based systems inherently requires large and representative test sets to evaluate whether DL systems generalise beyond their training datasets. Diverse Test Input Generators (TIGs) have been proposed to produce artificial inputs that expose issues of the DL systems by triggering misbehaviours. Unfortunately, such generated inputs may be invalid, i.e., not recognisable as part of the input domain, thus providing an unreliable quality assessment. Automated validators can ease the burden of manually checking the validity of inputs for human testers, although input validity is a concept difficult to formalise and, thus, automate. In this paper, we investigate to what extent TIGs can generate valid inputs, according to both automated and human validators. We conduct a large empirical study, involving 2 different automated validators, 220 human assessors, 5 different TIGs and 3 classification tasks. Our results show that 84% artificially generated inputs are valid, according to automated validators, but their expected label is not always preserved. Automated validators reach a good consensus with humans (78% accuracy), but still have limitations when dealing with feature-rich datasets.

Deep Neural Networks (DNN) are increasingly used as components of larger software systems that need to process complex data, such as images, written texts, audio/video signals. DNN predictions cannot be assumed to be always correct for several reasons, among which the huge input space that is dealt with, the ambiguity of some inputs data, as well as the intrinsic properties of learning algorithms, which can provide only statistical warranties. Hence, developers have to cope with some residual error probability. An architectural pattern commonly adopted to manage failure-prone components is the supervisor, an additional component that can estimate the reliability of the predictions made by untrusted (e.g., DNN) components and can activate an automated healing procedure when these are likely to fail, ensuring that the Deep Learning based System (DLS) does not cause damages, despite its main functionality being suspended. In this paper, we consider DLS that implement a supervisor by means of uncertainty estimation. After overviewing the main approaches to uncertainty estimation and discussing their pros and cons, we motivate the need for a specific empirical assessment method that can deal with the experimental setting in which supervisors are used, where the accuracy of the DNN matters only as long as the supervisor lets the DLS continue to operate. Then we present a large empirical study conducted to compare the alternative approaches to uncertainty estimation. We distilled a set of guidelines for developers that are useful to incorporate a supervisor based on uncertainty monitoring into a DLS.

Emerging applications such as Deep Learning are often data-driven, thus traditional approaches based on auto-tuners are not performance effective across the wide range of inputs used in practice. In the present paper, we start an investigation of predictive models based on machine learning techniques in order to optimize Convolution Neural Networks (CNNs). As a use-case, we focus on the ARM Compute Library which provides three different implementations of the convolution operator at different numeric precision. Starting from a collation of benchmarks, we build and validate models learned by Decision Tree and naive Bayesian classifier. Preliminary experiments on Midgard-based ARM Mali GPU show that our predictive model outperforms all the convolution operators manually selected by the library.

A tractogram is a virtual representation of the brain white matter. It is composed of millions of virtual fibers, encoded as 3D polylines, which approximate the white matter axonal pathways. To date, tractograms are the most accurate white matter representation and thus are used for tasks like presurgical planning and investigations of neuroplasticity, brain disorders, or brain networks. However, it is a well-known issue that a large portion of tractogram fibers is not anatomically plausible and can be considered artifacts of the tracking procedure. With Verifyber, we tackle the problem of filtering out such non-plausible fibers using a novel fully-supervised learning approach. Differently from other approaches based on signal reconstruction and/or brain topology regularization, we guide our method with the existing anatomical knowledge of the white matter. Using tractograms annotated according to anatomical principles, we train our model, Verifyber, to classify fibers as either anatomically plausible or non-plausible. The proposed Verifyber model is an original Geometric Deep Learning method that can deal with variable size fibers, while being invariant to fiber orientation. Our model considers each fiber as a graph of points, and by learning features of the edges between consecutive points via the proposed sequence Edge Convolution, it can capture the underlying anatomical properties. The output filtering results highly accurate and robust across an extensive set of experiments, and fast; with a 12GB GPU, filtering a tractogram of 1M fibers requires less than a minute. Verifyber implementation and trained models are available at https://github.com/FBK-NILab/verifyber.

As aerial robots are tasked to navigate environments of increased complexity, embedding collision tolerance in their design becomes important. In this survey we review the current state-of-the-art within the niche field of collision-tolerant micro aerial vehicles and present different design approaches identified in the literature, as well as methods that have focused on autonomy functionalities that exploit collision resilience. Subsequently, we discuss the relevance to biological systems and provide our view on key directions of future fruitful research.