Dionysios Diamantopoulos

Gagandeep Singh, Dionysios Diamantopoulos, Juan Gómez-Luna et al.

Machine learning has recently gained traction as a way to overcome the slow accelerator generation and implementation process on an FPGA. It can be used to build performance and resource usage models that enable fast early-stage design space exploration. First, training requires large amounts of data (features extracted from design synthesis and implementation tools), which is cost-inefficient because of the time-consuming accelerator design and implementation process. Second, a model trained for a specific environment cannot predict performance or resource usage for a new, unknown environment. In a cloud system, renting a platform for data collection to build an ML model can significantly increase the total-cost-ownership (TCO) of a system. Third, ML-based models trained using a limited number of samples are prone to overfitting. To overcome these limitations, we propose LEAPER, a transfer learning-based approach for prediction of performance and resource usage in FPGA-based systems. The key idea of LEAPER is to transfer an ML-based performance and resource usage model trained for a low-end edge environment to a new, high-end cloud environment to provide fast and accurate predictions for accelerator implementation. Experimental results show that LEAPER (1) provides, on average across six workloads and five FPGAs, 85% accuracy when we use our transferred model for prediction in a cloud environment with 5-shot learning and (2) reduces design-space exploration time for accelerator implementation on an FPGA by 10x, from days to only a few hours.

Dionysios Diamantopoulos, Roman Pletka, Slavisa Sarafijanovic et al.

Ransomware, a fearsome and rapidly evolving cybersecurity threat, continues to inflict severe consequences on individuals and organizations worldwide. Traditional detection methods, reliant on static signatures and application behavioral patterns, are challenged by the dynamic nature of these threats. This paper introduces three primary contributions to address this challenge. First, we introduce a ransomware emulator. This tool is designed to safely mimic ransomware attacks without causing actual harm or spreading malware, making it a unique solution for studying ransomware behavior. Second, we demonstrate how we use this emulator to create storage I/O traces. These traces are then utilized to train machine-learning models. Our results show that these models are effective in detecting ransomware, highlighting the practical application of our emulator in developing responsible cybersecurity tools. Third, we show how our emulator can be used to mimic the I/O behavior of existing ransomware thereby enabling safe trace collection. Both the emulator and its application represent significant steps forward in ransomware detection in the era of machine-learning-driven cybersecurity.

Nicolas Reategui, Roman Pletka, Dionysios Diamantopoulos

Ransomware represents a pervasive threat, traditionally countered at the operating system, file-system, or network levels. However, these approaches often introduce significant overhead and remain susceptible to circumvention by attackers. Recent research activity started looking into the detection of ransomware by observing block IO operations. However, this approach exhibits significant detection challenges. Recognizing these limitations, our research pivots towards enabling robust ransomware detection in storage systems keeping in mind their limited computational resources available. To perform our studies, we propose a kernel-based framework capable of efficiently extracting and analyzing IO operations to identify ransomware activity. The framework can be adopted to storage systems using computational storage devices to improve security and fully hide detection overheads. Our method employs a refined set of computationally light features optimized for ML models to accurately discern malicious from benign activities. Using this lightweight approach, we study a wide range of generalizability aspects and analyze the performance of these models across a large space of setups and configurations covering a wide range of realistic real-world scenarios. We reveal various trade-offs and provide strong arguments for the generalizability of storage-based detection of ransomware and show that our approach outperforms currently available ML-based ransomware detection in storage. Empirical validation reveals that our decision tree-based models achieve remarkable effectiveness, evidenced by higher median F1 scores of up to 12.8%, lower false negative rates of up to 10.9% and particularly decreased false positive rates of up to 17.1% compared to existing storage-based detection approaches.

Dionysios Diamantopoulos, Burkhard Ringlein, Mitra Purandare et al.

Specialized accelerators for tensor-operations, such as blocked-matrix operations and multi-dimensional convolutions, have been emerged as powerful architecture choices for high-performance Deep-Learning computing. The rapid development of frameworks, models, and precision options challenges the adaptability of such tensor-accelerators since the adaptation to new requirements incurs significant engineering costs. Programmable tensor accelerators offer a promising alternative by allowing reconfiguration of a virtual architecture that overlays on top of the physical FPGA configurable fabric. We propose an overlay (τ-VTA) and an optimization method guided by agile-inspired auto-tuning techniques. We achieve higher performance and faster convergence than state-of-art.