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Publications

2021

Visible and Thermal Image-Based Trunk Detection with Deep Learning for Forestry Mobile Robotics

Authors
da Silva, DQ; dos Santos, FN; Sousa, AJ; Filipe, V;

Publication
JOURNAL OF IMAGING

Abstract
Mobile robotics in forests is currently a hugely important topic due to the recurring appearance of forest wildfires. Thus, in-site management of forest inventory and biomass is required. To tackle this issue, this work presents a study on detection at the ground level of forest tree trunks in visible and thermal images using deep learning-based object detection methods. For this purpose, a forestry dataset composed of 2895 images was built and made publicly available. Using this dataset, five models were trained and benchmarked to detect the tree trunks. The selected models were SSD MobileNetV2, SSD Inception-v2, SSD ResNet50, SSDLite MobileDet and YOLOv4 Tiny. Promising results were obtained; for instance, YOLOv4 Tiny was the best model that achieved the highest AP (90%) and F1 score (89%). The inference time was also evaluated, for these models, on CPU and GPU. The results showed that YOLOv4 Tiny was the fastest detector running on GPU (8 ms). This work will enhance the development of vision perception systems for smarter forestry robots.

2021

Forensic Analysis of Tampered Digital Photos

Authors
Ferreira, S; Antunes, M; Correia, ME;

Publication
Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications - 25th Iberoamerican Congress, CIARP 2021, Porto, Portugal, May 10-13, 2021, Revised Selected Papers

Abstract
Deepfake in multimedia content is being increasingly used in a plethora of cybercrimes, namely those related to digital kidnap, and ransomware. Criminal investigation has been challenged in detecting manipulated multimedia material, by applying machine learning techniques to distinguish between fake and genuine photos and videos. This paper aims to present a Support Vector Machines (SVM) based method to detect tampered photos. The method was implemented in Python and integrated as a new module in the widely used digital forensics application Autopsy. The method processes a set of features resulting from the application of a Discrete Fourier Transform (DFT) in each photo. The experiments were made in a new and large dataset of classified photos containing both legitimate and manipulated photos, and composed of objects and faces. The results obtained were promising and reveal the appropriateness of using this method embedded in Autopsy, to help in criminal investigation activities and digital forensics.

2021

Semantic Services Catalog for Multiagent Systems Society

Authors
Santos, G; Canito, A; Carvalho, R; Pinto, T; Vale, ZA; Marreiros, G; Corchado, JM;

Publication
Advances in Practical Applications of Agents, Multi-Agent Systems, and Social Good. The PAAMS Collection - 19th International Conference, PAAMS 2021, Salamanca, Spain, October 6-8, 2021, Proceedings

Abstract

2021

Introduction to the Special Issue on Mobile Service Robotics and Associated Technologies

Authors
Manuel Silva;

Publication
Journal of Artificial Intelligence and Technology

Abstract

2021

A deep learning method for forecasting residual market curves

Authors
Coronati, A; Andrade, JR; Bessa, RJ;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
Forecasts of residual demand curves (RDCs) are valuable information for price-maker market agents since it enables an assessment of their bidding strategy in the market-clearing price. This paper describes the application of deep learning techniques, namely long short-term memory (LSTM) network that combines past RDCs and exogenous variables (e.g., renewable energy forecasts). The main contribution is to build up on the idea of transforming the temporal sequence of RDCs into a sequence of images, avoiding any feature reduction and exploiting the capability of LSTM in handling image data. The proposed method was tested with data from the Iberian day-ahead electricity market and outperformed machine learning models with an improvement of above 35% in both root mean square error and Frechet distance.

2021

A Conceptual Framework for an Integrated Information System to Enhance Urban Mobility

Authors
Duarte, SP; de Sousa, JP; de Sousa, JF;

Publication
INTERNATIONAL JOURNAL OF DECISION SUPPORT SYSTEM TECHNOLOGY

Abstract
The multiplicity of stakeholders in urban contexts can greatly increase the complexity of transportation systems. Since all stakeholders depend, to varying degrees, on the same data to get the information for their mobility, this work considers that an integrated information system, focused on their different needs, will significantly improve the efficiency of transportation systems. A stakeholder-focused system makes the provided information more relevant, while an integrated system fosters the sharing of the data that generates this information. To build such a system, a conceptual framework focused on stakeholders and their decision processes was developed. This new framework takes advantage of existing ones, such as the Zachman framework, the Enterprise Architecture Design, and the Multilevel Service Design. The proposed multidisciplinary approach, putting together information systems (IS) and service design concepts, has considerable potential in ensuring that the right information reaches each stakeholder at the right time.

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