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Publicações

Publicações por João Gama

2023

Explainable Predictive Maintenance

Autores
Pashami, S; Nowaczyk, S; Fan, Y; Jakubowski, J; Paiva, N; Davari, N; Bobek, S; Jamshidi, S; Sarmadi, H; Alabdallah, A; Ribeiro, RP; Veloso, B; Mouchaweh, MS; Rajaoarisoa, LH; Nalepa, GJ; Gama, J;

Publicação
CoRR

Abstract

2023

Estimating Instantaneous Vehicle Emissions

Autores
Andrade, T; Gama, J;

Publicação
38TH ANNUAL ACM SYMPOSIUM ON APPLIED COMPUTING, SAC 2023

Abstract
Road transportation emissions have increased in the last few decades and have been the primary source of pollutants in urban areas with ever-growing populations. In this context, it is important to have effective measures to monitor road emissions in regions. Creating an emissions inventory over a region that can map road emissions based on vehicle trips can be helpful. In this work, we show that it is possible to use raw GPS data to estimate vehicle-related levels of pollution in a region. By transforming the data using feature engineering and calculating the vehicle-specific power (VSP) as well as various specific pollutants by using a microscopic emissions model, we show the areas with higher emissions levels made by a fleet of taxis in Porto, Portugal.

2023

A DTW Approach for Complex Data A Case Study with Network Data Streams

Autores
Silva, PR; Vinagre, J; Gama, J;

Publicação
38TH ANNUAL ACM SYMPOSIUM ON APPLIED COMPUTING, SAC 2023

Abstract
Dynamic Time Warping (DTW) is a robust method to measure the similarity between two sequences. This paper proposes a method based on DTW to analyse high-speed data streams. The central idea is to decompose the network traffic into sequences of histograms of packet sizes and then calculate the distance between pairs of such sequences using DTW with Kullback-Leibler (KL) distance. As a baseline, we also compute the Euclidean Distance between the sequences of histograms. Since our preliminary experiments indicate that the distance between two sequences falls within a different range of values for distinct types of streams, we then exploit this distance information for stream classification using a Random Forest. The approach was investigated using recent internet traffic data from a telecommunications company. To illustrate the application of our approach, we conducted a case study with encrypted Internet Protocol Television (IPTV) network traffic data. The goal was to use our DTW-based approach to detect the video codec used in the streams, as well as the IPTV channel. Results strongly suggest that the DTW distance value between the data streams is highly informative for such classification tasks.

2022

MetroPT2: A Benchmark dataset for predictive maintenance

Autores
Veloso, B; Gama, J; Ribeiro, RP; Pereira, P;

Publicação

Abstract

2025

Modeling events and interactions through temporal processes: A survey

Autores
Liguori, A; Caroprese, L; Minici, M; Veloso, B; Spinnato, F; Nanni, M; Manco, G; Gama, J;

Publicação
NEUROCOMPUTING

Abstract
In real-world scenarios, numerous phenomena generate a series of events that occur in continuous time. Point processes provide a natural mathematical framework for modeling these event sequences. In this comprehensive survey, we aim to explore probabilistic models that capture the dynamics of event sequences through temporal processes. We revise the notion of event modeling and provide the mathematical foundations that underpin the existing literature on this topic. To structure our survey effectively, we introduce an ontology that categorizes the existing approaches considering three horizontal axes: modeling, inference and estimation, and application. We conduct a systematic review of the existing approaches, with a particular focus on those leveraging deep learning techniques. Finally, we delve into the practical applications where these proposed techniques can be harnessed to address real-world problems related to event modeling. Additionally, we provide a selection of benchmark datasets that can be employed to validate the approaches for point processes.

2023

Data Stream Analytics

Autores
Aguilar Ruiz, S; Bifet, A; Gama, J;

Publicação
Analytics

Abstract
[No abstract available]

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