João Miguel Costa de Sousa

Mr. João Miguel Costa de Sousa

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 March 2022 in Electronics
Verified
Journal Article
Open access
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IMIvo Marques
Ivo Marques
JSJoão Miguel Costa de Sousa
João Miguel Costa de Sousa
BSBruno Sá
Bruno Sá
Diogo André Veiga CostaDiogo André Veiga Costa
Diogo André Veiga Costa
PSPedro Sousa
Pedro Sousa
TGTiago Gomes
Tiago Gomes
With the current technological transformation in the automotive industry, autonomous vehicles are getting closer to the Society of Automative Engineers (SAE) automation level 5. This level corresponds to the full vehicle automation, where the driving system autonomously monitors and navigates the environment. With SAE-level 5, the concept of a Shared Autonomous Vehicle (SAV) will soon become a reality and mainstream. The main purpose of an SAV is to allow unrelated passengers to share an autonomous vehicle without a driver/moderator inside the shared space. However, to ensure their safety and well-being until they reach their final destination, active monitoring of all passengers is required. In this context, this article presents a microphone-based sensor system that is able to localize sound events inside an SAV. The solution is composed of a Micro-Electro-Mechanical System (MEMS) microphone array with a circular geometry connected to an embedded processing platform that resorts to Field-Programmable Gate Array (FPGA) technology to successfully process in the hardware the sound localization algorithms.

27 May 2025 in Electronics
Verified
Journal Article
Open access
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LCLuís Cunha
Luís Cunha
JSJoão Miguel Costa de Sousa
João Miguel Costa de Sousa
JAJosé Azevedo
José Azevedo
SPSandro Pinto
Sandro Pinto
TGTiago Gomes
Tiago Gomes
The automotive industry is fully shifting towards autonomous connected vehicles. By advancing vehicles’ intelligence and connectivity, the industry has enabled innovative functions such as advanced driver assistance systems (ADAS) in the direction of driverless cars. Such functions are often referred to as cyber-physical features, since almost all of them require collecting data from the physical environment to make automotive operation decisions and properly actuate in the physical world. However, increased functionalities result in increased complexity, which causes serious security vulnerabilities that are typically a result of mushrooming functionality and hence complexity. In a world where we keep seeing traditional mechanical systems shifting to x-by-wire solutions, the number of connected sensors, processing systems, and communication buses inside the car exponentially increases, raising several safety and security concerns. Because there is no safety without security, car manufacturers start struggling in making lightweight sensor and processing systems while keeping the security aspects a major priority. This article surveys the current technological challenges in securing autonomous vehicles and contributes a cross-layer analysis bridging hardware security primitives, real-world side-channel threats, and redundancy-based fault tolerance in automotive electronic control units (ECUs). It combines architectural insights with an evaluation of commercial support for TrustZone, trusted platform modules (TPMs), and lockstep platforms, offering both academic and industry audiences a grounded perspective on gaps in current hardware capabilities. Finally, it outlines future directions and presents a forward-looking vision for securing sensors and processing systems in the path toward fully safe and connected autonomous vehicles.

24 November 2025 in IEEE Access
Verified
Journal Article
Open access
ASAfonso Santos
Afonso Santos
JMJosé Martins
José Martins
JSJoão Miguel Costa de Sousa
João Miguel Costa de Sousa
MRManuel Rodríguez
Manuel Rodríguez
SPSandro Pinto
Sandro Pinto
Many industries, in particular automotive, are undergoing substantial transformations in their underlying electrical and electronic architecture (E/E), pushing for a transition from traditional flat architectures to more decentralized and zonal systems. Moreover, this industry’s demanding constraints and regulations (e.g., ISO26262) limit the application of COTS technologies to support this shift. Seeing this gap, semiconductor designers, like Arm, have been pushing for the Armv8-R processor architecture with specific features to cover the automotive industry’s needs. To address these demands, Arm introduced a dual-stage Memory Protection Unit (MPU) that supports hierarchical memory isolation and enables hypervisor deployment, enhancing its suitability for mixed-criticality real-time environments. In this context, the hypervisor emerges as a solution for consolidating different subsystems onto the same hardware platform, allowing the system to meet SWaP-C (Size, Weight, and Power-Cost) requirements. However, most hypervisor implementations are not designed to run on MMU-less devices. This paper describes the journey of re-designing Bao, an open-source lightweight Static Partitioning Hypervisor (SPH), to the new generation of real-time Arm processors. The core contribution focuses on leveraging the dual-stage MPU and the Armv8-R virtualization extensions to establish a predictable virtualization infrastructure. We evaluated the hypervisor’s performance on a multi-core platform based on the NXP S32Z270 SoC. Bao MMU-less demonstrated high efficiency, with less than 1% performance degradation and only a negligible increase in memory footprint. Additionally, the system exhibited a short boot time of 2.95ms, satisfying a key requirement for real-time systems.

9 May 2024 in IEEE Access
Verified
Journal Article
Open access
JSJoão Miguel Costa de Sousa
João Miguel Costa de Sousa
JMJosé Martins
José Martins
TGTiago Gomes
Tiago Gomes
SPSandro Pinto
Sandro Pinto
Virtualization technology has played a pivotal role in consolidating Mixed-Criticality Systems (MCS) onto a single computing platform. However, not all RISC-V processors present in Commercial Off-The-Shelf (COTS) platforms feature the so called Hypervisor extension, which poses a significant challenge in offering hardware virtualization capabilities in existing RISC-V silicon. This paper introduces HSP-V, a ready-to-run low-level software stack to provide static partitioning on RISC-V COTS platforms lacking hardware virtualization support. HSP-V leverages the Domain feature of the RISC-V Open Source Supervisor Binary Interface (OpenSBI) reference implementation to define partitions protected by the Physical Memory Protection (PMP) unit. Additionally, it provides other capabilities such as interrupt partitioning, direct interrupt injection, cache partitioning, and platform-level isolation for DMA-capable devices. The conducted evaluation assesses the impact of HSP-V on different empirical metrics, including domain boot time, interrupt latency, code size, and execution performance using micro and application benchmarks (LMBench and MiBench, respectively). HSP-V achieves highly deterministic interrupt latency with an average execution time of 457 ns (with a standard deviation of only 22 ns), with essentially zero traps in the Domain execution. In scenarios with cache interference, the HSP-V keeps the performance overhead as low as 0.39% for the best case scenario. Finally, all work described in this article is publicly available and open-sourced for the community to further evolve, port, and evaluate HSP-V in other hardware platforms.

12 September 2022 in arXiv
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SPSamuel Santos Pereira
Samuel Santos Pereira
JSJoão Miguel Costa de Sousa
João Miguel Costa de Sousa
SPSandro Pinto
Sandro Pinto
JMJosé Martins
José Martins
DCDavid Cerdeira
David Cerdeira
General-purpose operating systems (GPOS), such as Linux, encompass several million lines of code. Statistically, a larger code base inevitably leads to a higher number of potential vulnerabilities and inherently a more vulnerable system. To minimize the impact of vulnerabilities in GPOS, it has become common to implement security-sensitive programs outside the domain of the GPOS, i.e., in a Trusted Execution Environment (TEE). Arm TrustZone is the de-facto technology for implementing TEEs in Arm devices. However, over the last decade, TEEs have been successfully attacked hundreds of times. Unfortunately, these attacks have been possible due to the presence of several architectural and implementation flaws in TrustZone-based TEEs. In this paper, we propose Bao-Enclave, a virtualization-based solution that enables OEMs to remove security functionality from the TEE and move them into normal world isolated environments, protected from potentially malicious OSes, in the form of lightweight virtual machines (VMs). We evaluate Bao-Enclave on real hardware platforms and find out that Bao-Enclave may improve the performance of security-sensitive workloads by up to 4.8x, while significantly simplifying the TEE software TCB.