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Sobre

Sobre

Sou professor associado no Departamento de Ciência de Computadores da Faculdade de Ciências da Universidade do Porto. Completei o meu doutoramento na àrea de Ciência de Computadores em 1999, na mesma instituição. Desde então, os meus interesses têm-se centrado em linguagens de domínio específico, máquinas virtuais, sistemas distribuídos e, em particular, redes de sensores sem fios.

Tópicos
de interesse
Detalhes

Detalhes

  • Nome

    Luís Lopes
  • Cargo

    Responsável de Área
  • Desde

    01 janeiro 2009
003
Publicações

2025

Machine Learning Models for Indoor Positioning Using Bluetooth RSSI and Video Data: A Case Study

Autores
Mamede, T; Silva, N; Marques, ERB; Lopes, LMB;

Publicação
SENSORS

Abstract
Indoor Positioning Systems (IPSs) are essential for applications requiring accurate location awareness in indoor environments. However, achieving high precision remains challenging due to signal interference and environmental variability. This study proposes a multimodal IPS that integrates Bluetooth Received Signal Strength Indicator (RSSI) measurements and video imagery using machine learning (ML) and ensemble learning techniques. The system was implemented and deployed in the Hall of Biodiversity at the Natural History and Science Museum of the University of Porto. The venue presented significant deployment issues, namely restrictions on beacon placement and lighting conditions. We trained independent ML models on RSSI and video datasets, and combined them through ensemble learning methods. The experimental results from test scenarios, which included simulated visitor trajectories, showed that ensemble models consistently outperformed the RSSI-based and video-based models. These findings demonstrate that the use of multimodal data can significantly improve IPS accuracy despite constraints such as multipath interference, low lighting, and limited beacon infrastructure. Overall, they highlight the potential of multimodal data for deployments in complex indoor environments.

2024

Floralens: a Deep Learning Model for the Portuguese Native Flora

Autores
Filgueiras, A; Marques, ERB; Lopes, LMB; Marques, M; Silva, H;

Publicação
CoRR

Abstract

2023

Of Heat, Holes, and Hollow Places: The Semantics and Phonetic Value of T650

Autores
Lopes, L; Macleod, B; Sheseña, A;

Publicação
ESTUDIOS DE CULTURA MAYA

Abstract
The reading of the T650 glyph has been a puzzle for decades. Here, we analyze the semantic contexts in which the glyph appears together with available phonetic evidence to arrive at a phonetic reading of JOM. We provide grammatical reconstructions of the lexical contexts and discuss the rebuses involved in non semantic contexts.

2023

Jay: A software framework for prototyping and evaluating offloading applications in hybrid edge clouds

Autores
Silva, J; Marques, ERB; Lopes, LMB; Silva, FMA;

Publicação
SOFTWARE-PRACTICE & EXPERIENCE

Abstract
We present Jay, a software framework for offloading applications in hybrid edge clouds. Jay provides an API, services, and tools that enable mobile application developers to implement, instrument, and evaluate offloading applications using configurable cloud topologies, offloading strategies, and job types. We start by presenting Jay's job model and the concrete architecture of the framework. We then present the programming API with several examples of customization. Then, we turn to the description of the internal implementation of Jay instances and their components. Finally, we describe the Jay Workbench, a tool that allows the setup, execution, and reproduction of experiments with networks of hosts with different resource capabilities organized with specific topologies. The complete source code for the framework and workbench is provided in a GitHub repository.

2021

Energy-aware adaptive offloading of soft real-time jobs in mobile edge clouds

Autores
Silva, J; Marques, ERB; Lopes, LMB; Silva, F;

Publicação
JOURNAL OF CLOUD COMPUTING-ADVANCES SYSTEMS AND APPLICATIONS

Abstract
We present a model for measuring the impact of offloading soft real-time jobs over multi-tier cloud infrastructures. The jobs originate in mobile devices and offloading strategies may choose to execute them locally, in neighbouring devices, in cloudlets or in infrastructure cloud servers. Within this specification, we put forward several such offloading strategies characterised by their differential use of the cloud tiers with the goal of optimizing execution time and/or energy consumption. We implement an instance of the model using Jay, a software framework for adaptive computation offloading in hybrid edge clouds. The framework is modular and allows the model and the offloading strategies to be seamlessly implemented while providing the tools to make informed runtime offloading decisions based on system feedback, namely through a built-in system profiler that gathers runtime information such as workload, energy consumption and available bandwidth for every participating device or server. The results show that offloading strategies sensitive to runtime conditions can effectively and dynamically adjust their offloading decisions to produce significant gains in terms of their target optimization functions, namely, execution time, energy consumption and fulfilment of job deadlines.