2023
Authors
Garcia, D; Carias, J; Adao, T; Jesus, R; Cunha, A; Magalhaes, LG;
Publication
APPLIED SCIENCES-BASEL
Abstract
Object detection (OD) coupled with active learning (AL) has emerged as a powerful synergy in the field of computer vision, harnessing the capabilities of machine learning (ML) to automatically identify and perform image-based objects localisation while actively engaging human expertise to iteratively enhance model performance and foster machine-based knowledge expansion. Their prior success, demonstrated in a wide range of fields (e.g., industry and medicine), motivated this work, in which a comprehensive and systematic review of OD and AL techniques was carried out, considering reputed technical/scientific publication databases-such as ScienceDirect, IEEE, PubMed, and arXiv-and a temporal range between 2010 and December 2022. The primary inclusion criterion for papers in this review was the application of AL techniques for OD tasks, regardless of the field of application. A total of 852 articles were analysed, and 60 articles were included after full screening. Among the remaining ones, relevant topics such as AL sampling strategies used for OD tasks and groups categorisation can be found, along with details regarding the deep neural network architectures employed, application domains, and approaches used to blend learning techniques with those sampling strategies. Furthermore, an analysis of the geographical distribution of OD researchers across the globe and their affiliated organisations was conducted, providing a comprehensive overview of the research landscape in this field. Finally, promising research opportunities to enhance the AL process were identified, including the development of novel sampling strategies and their integration with different learning techniques.
2023
Authors
Reis, N; da Silva, JM; Correia, MV;
Publication
REMOTE SENSING
Abstract
The increased demand for and use of autonomous driving and advanced driver assistance systems has highlighted the issue of abnormalities occurring within the perception layers, some of which may result in accidents. Recent publications have noted the lack of standardized independent testing formats and insufficient methods with which to analyze, verify, and qualify LiDAR (Light Detection and Ranging)-acquired data and their subsequent labeling. While camera-based approaches benefit from a significant amount of long-term research, images captured through the visible spectrum can be unreliable in situations with impaired visibility, such as dim lighting, fog, and heavy rain. A redoubled focus upon LiDAR usage would combat these shortcomings; however, research involving the detection of anomalies and the validation of gathered data is few and far between when compared to its counterparts. This paper aims to contribute to expand the knowledge on how to evaluate LiDAR data by introducing a novel method with the ability to detect these patterns and complement other performance evaluators while using a statistical approach. Although it is preliminary, the proposed methodology shows promising results in the evaluation of an algorithm's confidence score, the impact that weather and road conditions may have on data, and fringe cases in which the data may be insufficient or otherwise unusable.
2023
Authors
Hammoudeh, M; Epiphaniou, G; Pinto, P;
Publication
JOURNAL OF SENSOR AND ACTUATOR NETWORKS
Abstract
2023
Authors
Silva, W; Gonçalves, T; Härmä, K; Schröder, E; Obmann, VC; Barroso, MC; Poellinger, A; Reyes, M; Cardoso, JS;
Publication
Scientific Reports
Abstract
The original version of this Article contained an error in the Acknowledgements section. “This work was partially funded by the Project TAMI—Transparent Artificial Medical Intelligence (NORTE- 01-0247-FEDER-045905) financed by ERDF—European Regional Fund through the North Portugal Regional Operational Program—NORTE 2020 and by the Portuguese Foundation for Science and Technology—FCT under the CMU—Portugal International Partnership, and also by the Portuguese Foundation for Science and Technology—FCT within PhD grants SFRH/BD/139468/2018 and 2020.06434.BD. The authors thank the Swiss National Science Foundation grant number 198388, as well as the Lindenhof foundation for their grant support.” now reads: “This work was supported by National Funds through the Portuguese Funding Agency, FCT–Foundation for Science and Technology Portugal, under Project LA/P/0063/2020, and also by the Portuguese Foundation for Science and Technology - FCT within PhD grants SFRH/BD/139468/2018 and 2020.06434.BD. The authors thank the Swiss National Science Foundation grant number 198388, as well as the Lindenhof foundation for their grant support.” The original Article has been corrected. © The Author(s) 2023.
2023
Authors
Silva, AS; Lima, J; Pereira, A; Silva, AMT; Gomes, HT;
Publication
COMPUTATIONAL SCIENCE AND ITS APPLICATIONS-ICCSA 2023 WORKSHOPS, PART VIII
Abstract
Studies dealing with route optimization have received considerable attention in recent years due to the increased demand for transportation services. For decades, scholars have developed robust algorithms designed to solve various Vehicle Routing Problems (VRP). In most cases, the focus is to present an algorithm that can overcome the shortest distances reported in other studies. On the other hand, execution time is also an important parameter that may limit the feasibility of the utilization in real scenarios for some applications. For this reason, in this work, a Guided Local Search (GLS) metaheuristic available in open-source OR-Tools will be tested to solve the Augerat instances of Capacitated Vehicle Routing Problems (CVRP). The stop criterion used here is the execution time, going from 1 s (standard) to 10 s, with a last run of 360 s. The numerical results demonstrate that increasing the execution time returns significant improvement in distance optimization. However, the optimization found considering high execution times can be expensive in terms of time, and not feasible for situations demanding faster algorithms, such as in Dynamic Vehicle Routing Problems (DVRP). Nonetheless, the GLS has proven to be a versatile algorithm for use where distance optimization is the main priority (high execution times) and in cases where faster algorithms are required (low execution times).
2023
Authors
Koch, I; Lopes, CT; Ribeiro, C;
Publication
ACM JOURNAL ON COMPUTING AND CULTURAL HERITAGE
Abstract
Archives are facing numerous challenges. On the one hand, archival assets are evolving to encompass digitized documents and increasing quantities of born-digital information in diverse formats. On the other hand, the audience is changing along with how it wishes to access archival material. Moreover, the interoperability requirements of cultural heritage repositories are growing. In this context, the Portuguese Archives started an ambitious program aiming to evolve its data model, migrate existing records, and build a new archival management system appropriate to both archival tasks and public access. The overall goal is to have a fine-grained and flexible description, more machine-actionable than the current one. This work describes ArchOnto, a linked open data model for archives, and rules for its automatic population from existing records. ArchOnto adopts a semantic web approach and encompasses the CIDOC Conceptual Reference Model and additional ontologies, envisioning interoperability with datasets curated by multiple communities of practice. Existing ISAD(G)-conforming descriptions are being migrated to the new model using the direct mappings provided here. We used a sample of 25 records associated with different description levels to validate the completeness and conformity of ArchOnto to existing data. This work is in progress and is original in several respects: (1) it is one of the first approaches to use CIDOC CRM in the context of archives, identifying problems and questions that emerged during the process and pinpointing possible solutions; (2) it addresses the balance in the model between the migration of existing records and the construction of new ones by archive professionals; and (3) it adopts an open world view on linking archival data to global information sources.
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