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1.
Sensors (Basel) ; 22(11)2022 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-35684825

RESUMO

Automatic identification of human facial expressions has many potential applications in today's connected world, from mental health monitoring to feedback for onscreen content or shop windows and sign-language prosodic identification. In this work we use visual information as input, namely, a dataset of face points delivered by a Kinect device. The most recent work on facial expression recognition uses Machine Learning techniques, to use a modular data-driven path of development instead of using human-invented ad hoc rules. In this paper, we present a Machine-Learning based method for automatic facial expression recognition that leverages information fusion architecture techniques from our previous work and soft voting. Our approach shows an average prediction performance clearly above the best state-of-the-art results for the dataset considered. These results provide further evidence of the usefulness of information fusion architectures rather than adopting the default ML approach of features aggregation.


Assuntos
Reconhecimento Facial , Face , Expressão Facial , Humanos , Aprendizado de Máquina , Política
2.
Sensors (Basel) ; 21(21)2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34770318

RESUMO

Multi-sensor fusion intends to boost the general reliability of a decision-making procedure or allow one sensor to compensate for others' shortcomings. This field has been so prominent that authors have proposed many different fusion approaches, or "architectures" as we call them when they are structurally different, so it is now challenging to prescribe which one is better for a specific collection of sensors and a particular application environment, other than by trial and error. We propose an approach capable of predicting the best fusion architecture (from predefined options) for a given dataset. This method involves the construction of a meta-dataset where statistical characteristics from the original dataset are extracted. One challenge is that each dataset has a different number of variables (columns). Previous work took the principal component analysis's first k components to make the meta-dataset columns coherent and trained machine learning classifiers to predict the best fusion architecture. In this paper, we take a new route to build the meta-dataset. We use the Sequential Forward Floating Selection algorithm and a T transform to reduce the features and match them to a given number, respectively. Our findings indicate that our proposed method could improve the accuracy in predicting the best sensor fusion architecture for multiple domains.


Assuntos
Algoritmos , Aprendizado de Máquina , Reprodutibilidade dos Testes
3.
Sensors (Basel) ; 20(8)2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32326125

RESUMO

Multi-sensor fusion refers to methods used for combining information coming from several sensors (in some cases, different ones) with the aim to make one sensor compensate for the weaknesses of others or to improve the overall accuracy or the reliability of a decision-making process. Indeed, this area has made progress, and the combined use of several sensors has been so successful that many authors proposed variants of fusion methods, to the point that it is now hard to tell which of them is the best for a given set of sensors and a given application context. To address the issue of choosing an adequate fusion method, we recently proposed a machine-learning data-driven approach able to predict the best merging strategy. This approach uses a meta-data set with the Statistical signatures extracted from data sets of a particular domain, from which we train a prediction model. However, the mentioned work is restricted to the recognition of human activities. In this paper, we propose to extend our previous work to other very different contexts, such as gas detection and grammatical face expression identification, in order to test its generality. The extensions of the method are presented in this paper. Our experimental results show that our extended model predicts the best fusion method well for a given data set, making us able to claim a broad generality for our sensor fusion method.

4.
Sensors (Basel) ; 19(17)2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31484423

RESUMO

In Ambient Intelligence (AmI), the activity a user is engaged in is an essential part of the context, so its recognition is of paramount importance for applications in areas like sports, medicine, personal safety, and so forth. The concurrent use of multiple sensors for recognition of human activities in AmI is a good practice because the information missed by one sensor can sometimes be provided by the others and many works have shown an accuracy improvement compared to single sensors. However, there are many different ways of integrating the information of each sensor and almost every author reporting sensor fusion for activity recognition uses a different variant or combination of fusion methods, so the need for clear guidelines and generalizations in sensor data integration seems evident. In this survey we review, following a classification, the many fusion methods for information acquired from sensors that have been proposed in the literature for activity recognition; we examine their relative merits, either as they are reported and sometimes even replicated and a comparison of these methods is made, as well as an assessment of the trends in the area.


Assuntos
Atividades Cotidianas , Técnicas Biossensoriais/métodos , Atividades Humanas , Humanos , Inquéritos e Questionários
5.
Sensors (Basel) ; 19(9)2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31035731

RESUMO

Sensors are becoming more and more ubiquitous as their price and availability continue to improve, and as they are the source of information for many important tasks. However, the use of sensors has to deal with noise and failures. The lack of reliability in the sensors has led to many forms of redundancy, but simple solutions are not always the best, and the precise way in which several sensors are combined has a big impact on the overall result. In this paper, we discuss how to deal with the combination of information coming from different sensors, acting thus as "virtual sensors", in the context of human activity recognition, in a systematic way, aiming for optimality. To achieve this goal, we construct meta-datasets containing the "signatures" of individual datasets, and apply machine-learning methods in order to distinguish when each possible combination method could be actually the best. We present specific results based on experimentation, supporting our claims of optimality.


Assuntos
Movimento , Reconhecimento Automatizado de Padrão/métodos , Humanos , Aprendizado de Máquina , Integração de Sistemas
6.
Sci Total Environ ; 571: 388-97, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27473772

RESUMO

Shrimp farm aquaculture causes environmental impacts, notably decreased water quality due to the release of nutrient-rich effluents. Pond wastewater is usually discharged without treatment, and tidal conditions are not taken into account in the management plans. However, natural variability of nutrients makes difficult field evaluation and attribution of impacts. Here we implemented a three-dimensional coupled hydrodynamic-biogeochemical model (spatial resolution=50m×50m, time resolution=4s) in order to evaluate the dispersion conditions under specific tidal conditions of nutrient discharges from a semi-intensive shrimp farm during spring and neap tide. Ammonia was quickly assimilated by plankton and its concentration recovered initial levels 10days after the beginning of the harvest. Due to the higher salinity of the pond effluents, shrimp farm discharges accumulate in waters and sediments of the upper lagoon creeks, mostly affecting the benthos, thus implying a potential risk of shrimp farm self-contamination. Maximum concentrations of most biogeochemical tracers occurred when the harvest ends and the ponds are fully emptied. We show that maximum nutrient concentrations can be reduced by ~10% when the harvest ends during spring tides compared to harvests ending during neap tides. This work may be useful to improve the management of shrimp farm effluents by reducing, easily and at little cost, nutrient impacts on tropical and sub-tropical receiving ecosystems.


Assuntos
Aquicultura , Penaeidae/fisiologia , Poluentes Químicos da Água/análise , Poluição Química da Água/prevenção & controle , Qualidade da Água , Animais , Monitoramento Ambiental , México
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