Marco Caccamo

Today’s embedded microcontrollers (MCUs) are designed to achieve both timing predictability and low energy consumption. This is usually done by using features that trade energy savings for faster execution ( e.g., DVFS or prefetcher) and the ones that can improve both time and energy performance but are limited in size ( e.g., core-coupled memories and caches). In this paper, we evaluate the impact of core-coupled memories in this regard on the example of two low-powered embedded MCUs, each with a different level of hardware support. Our study reveals the importance of core-coupled memory allocation for both timing and energy performances. The performance gains are particularly significant on simple devices where DVFS and caches are not available. We formulate a memory allocation problem using integer linear programming to minimize power consumption under timing and memory constraints. We also propose a heuristic with quadratic time complexity in the number of tasks to solve the allocation problem. The evaluation based on real-world benchmarks and a case study demonstrates an energy consumption reduction of 10-20% when compared to the default MCU configuration ( i.e., maximal CPU frequency and program’s code in Flash).

With the increasing popularity of photovoltaic (PV) equipment in residential and commercial buildings, there is a pressing need for systems that maximize energy efficiency and self-consumption. This paper introduces an integrated management framework for retrofitting existing infrastructures, enabling high photovoltaic (PV) self-consumption in residential buildings through a rule-based control strategy. The framework supports three service classes—defined by user-level Quality of Service (QoS) parameters—and monitors battery voltage along with grid power exchange to coordinate heat pumps, batteries, and hot water cylinders. Experimental deployment in a residential testbed achieved up to 89% PV self-consumption while keeping daily grid usage below 0.5 kWh. Ablation experiments on battery size further demonstrated the approach’s robustness to reduced storage capacities. The use of Commercial-Off-The-Shelf (COTS) components underscores the minimal intrusiveness of this solution, highlighting its potential for seamlessly integrating diverse, vendor-specific equipment into a coordinated control system.

How can one tamper with data that does not exist? Motivated by this question, we present the Burning Fetch eXecution (BFX) paradigm. Data in-use is vulnerable, and the current focus on encrypting and/or isolating in-use data has fallen short. Frequently reported breaches of “secure” hardware and indispensable overhead with encryption schemes confirm that trust is the modern bottleneck. This work tackles the gap in existing safeguarding technology by avoiding byte-level decryption until it is immediately fetched by the processor, only to burn it right after. We perform on-the-fetch data decryption, immediately followed by burning , i.e., erasing right after processing cycles. Thus, BFX minimizes the existence of sensitive data in-use . BFX does not demand new processing hardware units nor requires restructuring application software. Three pillars set the BFX paradigm apart: (1) zero-trust multi-party confidentiality with (2) security rooted in transparency, and (3) high performance. By tackling the root of the issue, BFX enables a zero-trust multi-partied sharing without showing scenarios that were previously unthinkable. We showcase the impact of the BFX in a scenario with a highly privileged cloud insider attacker present. We exercise a sensitive mission whereby a third-party cloud processes fourth-party confidential real-time data streamed by a drone swarm. To further highlight the zero-trust nature of BFX, we assume the inference model (code) stream-processing on swarm data to be top-secret and owned by yet another party. The unknown threat, however, is the compromised processing system (cloud) where sensitive code and data are about to be deployed by all other parties-thanks to misplaced trust.

Pipelining deep neural networks (DNNs) across multiple Edge Tensor Processing Units (TPUs) can enhance on-device performance by increasing the capacity for DNN parameters caching and enabling pipeline parallelism. Effective deployment on pipelined Edge TPUs requires a partitioning tool to divide the DNN into segments, each assigned to a different Edge TPU in the pipeline. Achieving balanced workload distribution across these segments is crucial for optimal timing performance. However, workload balancing across Edge TPUs is challenging, as DNN execution time is influenced by proprietary hardware architecture and compiler internals, forming a black-box function inaccessible to partitioning tools. To address this challenge, this article introduces SAPar , a new surrogate-assisted DNN partitioner that integrates a neighborhood search engine with a surrogate-assisted evaluator for effective and efficient DNN partitioning. The neighborhood search engine systematically explores the decision space, guided by knowledge obtained from empirical insights and neighborhood evaluation feedback provided by the surrogate-assisted evaluator. The evaluator cooperatively applies an accurate yet time-consuming latency profiler and an efficient graph transformer-based surrogate model , achieving both precision and scalability. Experiments on real Edge TPU hardware demonstrate that SAPar achieves significantly better pipeline performance than Google’s current profiling-based partitioner with an 8.82× to 110× speedup in partitioning time. Moreover, SAPar reduces the bottleneck latency by 8.93% to 44.15% across five classic DNN models compared with a state-of-the-art reinforcement learning-based partitioner.

Capturing latent variations ("contexts") is key to deploying reinforcement-learning (RL) agents beyond their training regime. We recast context-based RL as a dual inference-control problem and formally characterize two properties and their hierarchy: observation sufficiency (preserving all predictive information) and control sufficiency (retaining decision-making relevant information). Exploiting this dichotomy, we derive a contextual evidence lower bound(ELBO)-style objective that cleanly separates representation learning from policy learning and optimizes it with Bottlenecked Contextual Policy Optimization (BCPO), an algorithm that places a variational information-bottleneck encoder in front of any off-policy policy learner. On standard continuous-control benchmarks with shifting physical parameters, BCPO matches or surpasses other baselines while using fewer samples and retaining performance far outside the training regime. The framework unifies theory, diagnostics, and practice for context-based RL.

Many real-time problems can be characterized as combinatorial optimization problems where exact solutions are infeasible at scale. As problem complexity grows, handcrafted heuristics become increasingly difficult to design. Reinforcement learning (RL) has emerged as a promising alternative, enabling the discovery of decision-making policies without requiring explicit supervision. While RL does not guarantee optimality, it provides adaptive heuristics to solve complex problems. This paper explores the potential of RL for real-time resource management, outlining key principles, demonstrating an application to directed acyclic graph (DAG) scheduling, and identifying open challenges for future research.

Unmanned Aerial Vehicle (UAV) Coverage Path Planning (CPP) is critical for applications such as precision agriculture and search and rescue. While traditional methods rely on discrete grid-based representations, real-world UAV operations require power-efficient continuous motion planning. We formulate the UAV CPP problem in a continuous environment, minimizing power consumption while ensuring complete coverage. Our approach models the environment with variable-size axis-aligned rectangles and UAV motion with curvature-constrained Bézier curves. We train a reinforcement learning agent using an action-mapping-based Soft Actor-Critic (AM-SAC) algorithm employing a self-adaptive curriculum. Experiments on both procedurally generated and hand-crafted scenarios demonstrate the effectiveness of our method in learning energy-efficient coverage strategies.

In this note, we present the synthesis of secure-by-construction controllers that address safety and security properties simultaneously in cyber-physical systems. Our focus is on studying a specific security property called opacity, which characterizes the system's ability to maintain plausible deniability of its secret behavior in the presence of an intruder. These controllers are synthesized based on a concept of so-called (augmented) control barrier functions (CBFs). We propose conditions that facilitate the construction of the desired (augmented) CBFs and their corresponding secure-by-construction controllers. To compute these functions, we propose an iterative scheme that leverages iterative sum-of-square programming techniques. This approach enables efficient computation of these functions, particularly for polynomial systems. Finally, we validate the effectiveness of our results through a case study of a vehicle.