arXiv subjects

Pedro Antunes

Publications and source records attributed to Pedro Antunes.

6 recordsLinked to original sources

arXiv2026

bitSMM: A bit-Serial Matrix Multiplication Accelerator

Neural-network (NN) inference is increasingly present on-board spacecraft to reduce downlink bandwidth and enable timely decision making. However, the power and reliability constraints of space missions limit the applicability of many state-of-the-art NN accelerators. This paper presents bitSMM, a bit-serial matrix multiplication accelerator built around a systolic array of bit-serial multiply--accumulate (MAC) units. The design supports runtime-configurable operand precision from 1 to 16 bits and evaluates two MAC variants: a Booth-inspired architecture and a standard binary multiplication with correction architecture. We implement bitSMM in [System]Verilog and evaluate it on an AMD ZCU104 FPGA and through ASIC physical implementation using the asap7 and nangate45 process design kits. On the FPGA, bitSMM achieves up to 19.2~GOPS and 2.973~GOPS/W, and in asap7 it achieves up to 73.22~GOPS, 552~GOPS/mm$^2$, and 40.8~GOPS/W.

cs.AR↗

arXiv2026

Evaluating Four FPGA-accelerated Space Use Cases based on Neural Network Algorithms for On-board Inference

Space missions increasingly deploy high-fidelity sensors that produce data volumes exceeding onboard buffering and downlink capacity. This work evaluates FPGA acceleration of neural networks (NNs) across four space use cases on the AMD ZCU104 board. We use Vitis AI (AMD DPU) and Vitis HLS to implement inference, quantify throughput and energy, and expose toolchain and architectural constraints relevant to deployment. Vitis AI achieves up to 34.16$\times$ higher inference rate than the embedded ARM CPU baseline, while custom HLS designs reach up to 5.4$\times$ speedup and add support for operators (e.g., sigmoids, 3D layers) absent in the DPU. For these implementations, measured MPSoC inference power spans 1.5-6.75 W, reducing energy per inference versus CPU execution in all use cases. These results show that NN FPGA acceleration can enable onboard filtering, compression, and event detection, easing downlink pressure in future missions.

cs.AR↗

arXiv2025

AIvailable: A Software-Defined Architecture for LLM-as-a-Service on Heterogeneous and Legacy GPUs

The rise of Large Language Models (LLM) has increased the need for scalable, high-performance inference systems, yet most existing frameworks assume homogeneous, resource-rich hardware, often unrealistic in academic, or resource-constrained settings. We introduce AIvailable, a low-cost, highly available LLM-as-a-Service (LLMaaS) platform, that uses a software-defined approach for running LLMs across heterogeneous and legacy GPU nodes, including NVIDIA and AMD devices, with a focus on fully utilizing each node's VRAM. AIvailable operates as a fully GPU-accelerated inference without CPU fallbacks, featuring a unified client interface that allows seamless interaction with all deployed LLMs through a single logical unit. The architecture comprises four main components: the Client Interface for user access, the Service Frontend for secure request routing and load balancing, the SDAI Controller for orchestration, deployment, and monitoring, and the Service Backend of heterogeneous GPU nodes executing workloads. By abstracting GPU-specific details and providing dynamic, VRAM-aware allocation and reallocation of models, AIvailable ensures efficient use of resources and resilience against failures or workload fluctuations. Targeting academic labs, private companies, and other constrained organizations, it supports diverse open LLMs helping democratize generative AI through the repurposing of legacy GPUs.

cs.DC↗

arXiv2025

HashKitty: Distributed Password Analysis

This article documents the HashKitty platform, a distributed solution for password analysis based on the hashcat tool, designed to improve efficiency in both offensive and defensive security operations. The main objectives of this work are to utilise and characterise the hashcat tool, to develop a central platform that connects various computational nodes, to allow the use of nodes with different equipment and manufacturers, to distribute tasks among the nodes through a web platform, and to perform distributed password analysis. The results show that the presented solution achieves the proposed objectives, demonstrating effectiveness in workload distribution and password analysis using different types of nodes based on various operating systems and architectures. The architecture of HashKitty is based on a scalable and modular distributed architecture, composed of several components such as computational nodes, integration and control software, a web platform that implements our API, and database servers. In order to achieve a fast and organised development process for our application we used multiple frameworks, runtimes and libraries. For the communication between the computational nodes and the other software we made use of websockets so that we have real-time updates between them.

cs.CR↗

arXiv2025

FPGA-Based Neural Network Accelerators for Space Applications: A Survey

Space missions are becoming increasingly ambitious, necessitating high-performance onboard spacecraft computing systems. In response, field-programmable gate arrays (FPGAs) have garnered significant interest due to their flexibility, cost-effectiveness, and radiation tolerance potential. Concurrently, neural networks (NNs) are being recognized for their capability to execute space mission tasks such as autonomous operations, sensor data analysis, and data compression. This survey serves as a valuable resource for researchers aiming to implement FPGA-based NN accelerators in space applications. By analyzing existing literature, identifying trends and gaps, and proposing future research directions, this work highlights the potential of these accelerators to enhance onboard computing systems.

cs.AR↗

arXiv2016

A Design Science Method for Emerging Decision Support Environments

Emerging technologies and business models require organisations to continuously deal with complex, dynamic and unstructured issues, leading to the need for newer forms of decision support systems (DSS). However, in emerging environments the existing knowledge base can be scattered, unstructured, and sometimes conflicting, which challenges any efforts in designing DSS. This paper highlights the role of design science methods in developing these emerging areas, and suggests a design science method that focuses on consolidating the knowledge base by ontologically grounding experience and expertise. The proposed method is illustrated in the context of a published case, and validated by practically applying it to develop a crowdsourcing decision tool. The study contributes with recommendations on how to consolidate the knowledge base and design DSS artefacts.

cs.CY↗