2023
Autores
Tome, ES; Ribeiro, RP; Dutra, I; Rodrigues, A;
Publicação
SENSORS
Abstract
The early detection of fire is of utmost importance since it is related to devastating threats regarding human lives and economic losses. Unfortunately, fire alarm sensory systems are known to be prone to failures and frequent false alarms, putting people and buildings at risk. In this sense, it is essential to guarantee smoke detectors' correct functioning. Traditionally, these systems have been subject to periodic maintenance plans, which do not consider the state of the fire alarm sensors and are, therefore, sometimes carried out not when necessary but according to a predefined conservative schedule. Intending to contribute to designing a predictive maintenance plan, we propose an online data-driven anomaly detection of smoke sensors that model the behaviour of these systems over time and detect abnormal patterns that can indicate a potential failure. Our approach was applied to data collected from independent fire alarm sensory systems installed with four customers, from which about three years of data are available. For one of the customers, the obtained results were promising, with a precision score of 1 with no false positives for 3 out of 4 possible faults. Analysis of the remaining customers' results highlighted possible reasons and potential improvements to address this problem better. These findings can provide valuable insights for future research in this area.
2023
Autores
Dahlqvist, F; Neves, R;
Publicação
Log. Methods Comput. Sci.
Abstract
2023
Autores
Ferreira Ribeiro, JE; Silva, JG; Aguiar, A;
Publicação
CoRR
Abstract
2023
Autores
Alves, IM; Carvalho, LM; Lopes, JAP;
Publicação
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
Abstract
This paper proposes a novel probabilistic model for quantifying the impact of demand flexibility (DF) on the long-term generation system adequacy via Sequential Monte Carlo Simulation (SMCS) method. Unlike load shedding, DF can be considered an important instrument to postpone bulk consumption from periods with limited reserves to periods with more generating capacity available, avoiding load shedding and increasing the integration of variable renewable generation, such as wind power. DF has been widely studied in terms of its contribution to the system's social welfare, resulting in numerous innovative approaches ranging from the flexibility modeling of individual electric loads to the definition of aggregation strategies for optimally deploying this lever in competitive markets. To add to the current state-of-the-art, a new model is proposed to quantify DF impact on the traditional reliability indices, such as the Loss of Load Expectation (LOLE) and the Expected Energy Not Supplied (EENS), enabling a new perspective for the DF value. Given the diverse mechanisms associated with DF of different consumer types, the model considers the uncertainties associated with the demand flexibility available in each hour of the year and with the rebound effect, i.e., the subsequent change of consumption patterns following a DF mobilization event. Case studies based on a configuration of the IEEE-RTS 79 test system with wind power demonstrate that the DF can substantially improve the reliability indices of the static and operational reserve while decreasing the curtailment of variable generation cause by unit scheduling priorities or by short-term generation/demand imbalances.
2023
Autores
Bhanu, M; Priya, S; Moreira, JM; Chandra, J;
Publicação
APPLIED INTELLIGENCE
Abstract
Taxi demand prediction in a city is a highly demanded smart city research application for better traffic strategies formulation. It is essential for the interest of the commuters and the taxi companies both to have an accurate measure of taxi demands at different regions of a city and at varying time intervals. This reduces the cost of resources, efforts and meets the customers' satisfaction at its best. Modern predictive models have shown the potency of Deep Neural Networks (DNN) in this domain over any traditional, statistical, or Tensor-Based predictive models in terms of accuracy. The recent DNN models using leading technologies like Convolution Neural Networks (CNN), Graph Convolution Networks (GCN), ConvLSTM, etc. are not able to efficiently capture the existing spatio-temporal characteristics in taxi demand time-series. The feature aggregation techniques in these models lack channeling and uniqueness causing less distinctive but overlapping feature space which results in a compromised prediction performance having high error propagation possibility. The present work introduces Spatio-Temporal Aggregator Predictor (ST-A(G)P), a DNN model which aggregates spatio-temporal features into (1) non-redundant and (2) highly distinctive feature space and in turn helps (3) reduce noise propagation for a high performing multi-step predictive model. The proposed model integrates the effective feature engineering techniques of machine learning approach with the non-linear capability of a DNN model. Consequently, the proposed model is able to use only the informative features responsible for the objective task with reduce noise propagation. Unlike, existing DNN models, ST-A(G)P is able to induce these qualities of feature aggregation without the use of Multi-Task Learning (MTL) approach or any additional supervised attention that existing models need for their notable performance. A considerable high-performance gain of 25 - 37% on two real-world city taxi datasets by ST-A(G)P over the state-of-art models on standard benchmark metrics establishes the efficacy of the proposed model over the existing ones.
2023
Autores
Bras, GR; Preto, MT; Daniel, AD; Teixeira, AAC;
Publicação
ADMINISTRATIVE SCIENCES
Abstract
The aim of this study is to test the multidimensional construct of the Entrepreneurial University (EU), and therefore to confirm whether EU factors make a positive contribution to regional competitiveness. Data were collected from ten Portuguese Public Universities (PPUs) through a self-administered questionnaire. First- and second-order confirmatory factor analyses (CFA) were performed through factor and multiple linear regression analyses. The main findings show that EU related factors-perceived and combined with actual regional metrics-especially entrepreneurial supporting measures, positively contributed to regional competitiveness. This study shows policy makers that universities are not merely cost centres but provide knowledge spillovers that can have a positive influence on regional competitiveness.
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