Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

Publications by HASLab

2024

Trainability issues in quantum policy gradients

Authors
Sequeira, A; Santos, LP; Barbosa, LS;

Publication
MACHINE LEARNING-SCIENCE AND TECHNOLOGY

Abstract
This research explores the trainability of Parameterized Quantum Circuit-based policies in Reinforcement Learning, an area that has recently seen a surge in empirical exploration. While some studies suggest improved sample complexity using quantum gradient estimation, the efficient trainability of these policies remains an open question. Our findings reveal significant challenges, including standard Barren Plateaus with exponentially small gradients and gradient explosion. These phenomena depend on the type of basis-state partitioning and the mapping of these partitions onto actions. For a polynomial number of actions, a trainable window can be ensured with a polynomial number of measurements if a contiguous-like partitioning of basis-states is employed. These results are empirically validated in a multi-armed bandit environment.

2024

The Blocklace: A Universal, Byzantine Fault-Tolerant, Conflict-free Replicated Data Type

Authors
Almeida, PS; Shapiro, E;

Publication
CoRR

Abstract

2024

A Framework for Consistency Models in Distributed Systems

Authors
Almeida, PS;

Publication
CoRR

Abstract

2024

Validating multiple variants of an automotive light system with Alloy 6

Authors
Cunha, A; Macedo, N; Liu, C;

Publication
INTERNATIONAL JOURNAL ON SOFTWARE TOOLS FOR TECHNOLOGY TRANSFER

Abstract
This paper reports on the development and validation of a formal model for an automotive adaptive exterior lights system (ELS) with multiple variants in Alloy 6, which is the most recent version of the Alloy lightweight formal specification language that supports mutable relations and temporal logic. We explore different strategies to address variability, one in pure Alloy and another through an annotative language extension. We then show how Alloy and its Analyzer can be used to validate systems of this nature, namely by checking that the reference scenarios are admissible, and to automatically verify whether the established requirements hold. A prototype was developed to translate the provided validation sequences into Alloy and back to further automate the validation process. The resulting ELS model was validated against the provided validation sequences and verified for most of requirements for all variants.

2024

Designing Software with Complex Configurations

Authors
Cunha, A;

Publication
CoRR

Abstract

2024

Can Current SDS Controllers Scale To Modern HPC Infrastructures?

Authors
Miranda, M; Tanimura, Y; Haga, J; Ruhela, A; Harrell, SL; Cazes, J; Macedo, R; Pereira, J; Paulo, J;

Publication
SC24-W: Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis, Atlanta, GA, USA, November 17-22, 2024

Abstract
Modern supercomputers host numerous jobs that compete for shared storage resources, causing I/O interference and performance degradation. Solutions based on software- defined storage (SDS) emerged to address this issue by coordinating the storage environment through the enforcement of QoS policies. However, these often fail to consider the scale of modern HPC infrastructures.In this work, we explore the advantages and shortcomings of state-of-the-art SDS solutions and highlight the scale of current production clusters and their rising trends. Furthermore, we conduct the first experimental study that sheds new insights into the performance and scalability of flat and hierarchical SDS control plane designs.Our results, using the Frontera supercomputer, show that a flat design with a single controller can scale up to 2,500 nodes with an average control cycle latency of 41 ms, while hierarchical designs can handle up to 10,000 nodes with an average latency ranging between 69 and 103 ms. © 2024 IEEE.

  • 8
  • 255