I am a Ph.D. Student since late 2023 at the Computer Science and Engineering Department at Chalmers University of Technology. The topic of my Ph.D. is "Assurance in Autonomous Systems", and my research interests include (but are not limited to) runtime assurance; explainability, especially on artificial intelligence; and the formal specification, verification, and synthesis of cyber-physical systems. My research is funded by Wallenberg AI, Autonomous Systems, and Software Program.
Class activation mapping (CAM) is a widely adopted class of saliency methods used to explain the behavior of convolutional neural networks (CNNs). These methods generate heatmaps that highlight the parts of the input most relevant to the CNN output. Various CAM methods have been proposed, each distinguished by the expressions used to derive heatmaps. In general, users look for heatmaps with specific properties that reflect different aspects of CNN functionality. These may include similarity to ground truth, robustness, equivariance, and more. Although existing CAM methods implicitly encode some of these properties in their expressions, they do not allow for variability in heatmap generation following the user's intent or domain knowledge. In this paper, we address this limitation by introducing SyCAM, a metric-based approach for synthesizing CAM expressions tailored to specific evaluation metrics. Given a predefined metric for saliency maps, SyCAM automatically generates CAM expressions optimized for that metric. We specifically explore a syntax-guided synthesis instantiation of SyCAM, where CAM expressions are derived based on predefined syntactic constraints and the given metric. Using several well-known evaluation metrics, we demonstrate the efficacy and flexibility of our approach in generating targeted heatmaps. We compare SyCAM with other well-known CAM methods on three prominent models: ResNet50, VGG16, and VGG19.
In Evolutionary Game Theory (EGT), a population reaches a Nash equilibrium when none of the agents can improve its objective by solely changing its strategy on its own. Roughly speaking, this equilibrium is a protection against betrayal. Generalized Nash Equilibrium (GNE) is a more complex version of this idea with important implications in real-life problems in economics, wireless communication, the electricity market, or engineering among other areas. In this paper, we propose a first approach to GNE with Membrane Computing techniques and show how GNE problems can be modeled with P systems, bridging both areas and opening a door for a flow of problems and solutions in both directions.
The improvement of air-quality in urban areas is one of the main concerns of public government bodies. This concern emerges from the evidence between the air quality and the public health. Major efforts from government bodies in this area include monitoring and forecasting systems, banning more pollutant motor vehicles, and traffic limitations during the periods of low-quality air. In this work, a proposal for dynamic prices in regulated parking services is presented. The dynamic prices in parking service must discourage motor vehicles parking when low-quality episodes are predicted. For this purpose, diverse deep learning strategies are evaluated. They have in common the use of collective air-quality measurements for forecasting labels about air quality in the city. The proposal is evaluated by using economic parameters and deep learning quality criteria at Madrid (Spain).
The main objective of this work is to model some time series: the Madrid air pollution data. Nowadays, Deep Learning systems are becoming really important for time series modelling. There are different neural networks dedicated to this task, such as convolutional neural networks or recurrent neural networks. This kind of models manage to learn long time dependencies between the data, something really useful for time series analysis. Some of these models are introduced in this work, as well as some statistical models like ARIMA. After studying and comparing them, one special network is chosen: U-Time. U-Time is "a fully feed-forward deep learning approach to physiological time series segmentation developed for the analysis of sleep data". It is possible to modify U-Time and to train that variant with the air pollution data. After that, we get a model that maps sequential inputs to labels previously defined related to the pollution levels.