Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sensors (Basel) ; 22(2)2022 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-35062415

RESUMO

This paper introduces a procedure to compare the functional behaviour of individual units of electronic hardware of the same type. The primary use case for this method is to estimate the functional integrity of an unknown device unit based on the behaviour of a known and proven reference unit. This method is based on the so-called virtual sensor network (VSN) approach, where the output quantity of a physical sensor measurement is replicated by a virtual model output. In the present study, this approach is extended to model the functional behaviour of electronic hardware by a neural network (NN) with Long-Short-Term-Memory (LSTM) layers to encapsulate potential time-dependence of the signals. The proposed method is illustrated and validated on measurements from a remote-controlled drone, which is operated with two variants of controller hardware: a reference controller unit and a malfunctioning counterpart. It is demonstrated that the presented approach successfully identifies and describes the unexpected behaviour of the test device. In the presented case study, the model outputs a signal sample prediction in 0.14 ms and achieves a reconstruction accuracy of the validation data with a root mean square error (RMSE) below 0.04 relative to the data range. In addition, three self-protection features (multidimensional boundary-check, Mahalanobis distance, auxiliary autoencoder NN) are introduced to gauge the certainty of the VSN model output.

2.
Sensors (Basel) ; 21(21)2021 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-34770575

RESUMO

Autonomous Vehicles (AVs) have the potential to solve many traffic problems, such as accidents, congestion and pollution. However, there are still challenges to overcome, for instance, AVs need to accurately perceive their environment to safely navigate in busy urban scenarios. The aim of this paper is to review recent articles on computer vision techniques that can be used to build an AV perception system. AV perception systems need to accurately detect non-static objects and predict their behaviour, as well as to detect static objects and recognise the information they are providing. This paper, in particular, focuses on the computer vision techniques used to detect pedestrians and vehicles. There have been many papers and reviews on pedestrians and vehicles detection so far. However, most of the past papers only reviewed pedestrian or vehicle detection separately. This review aims to present an overview of the AV systems in general, and then review and investigate several detection computer vision techniques for pedestrians and vehicles. The review concludes that both traditional and Deep Learning (DL) techniques have been used for pedestrian and vehicle detection; however, DL techniques have shown the best results. Although good detection results have been achieved for pedestrians and vehicles, the current algorithms still struggle to detect small, occluded, and truncated objects. In addition, there is limited research on how to improve detection performance in difficult light and weather conditions. Most of the algorithms have been tested on well-recognised datasets such as Caltech and KITTI; however, these datasets have their own limitations. Therefore, this paper recommends that future works should be implemented on more new challenging datasets, such as PIE and BDD100K.


Assuntos
Pedestres , Acidentes de Trânsito , Algoritmos , Humanos , Percepção , Tempo (Meteorologia)
3.
Comput Ind Eng ; 147: 106610, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32834426

RESUMO

Ant Colony algorithm has been applied to various optimisation problems, however, most of the previous work on scaling and parallelism focuses on Travelling Salesman Problems (TSPs). Although useful for benchmarks and new idea comparison, the algorithmic dynamics do not always transfer to complex real-life problems, where additional meta-data is required during solution construction. This paper explores how the benchmark performance differs from real-world problems in the context of Ant Colony Optimization (ACO) and demonstrate that in order to generalise the findings, the algorithms have to be tested on both standard benchmarks and real-world applications. ACO and its scaling dynamics with two parallel ACO architectures - Independent Ant Colonies (IAC) and Parallel Ants (PA). Results showed that PA was able to reach a higher solution quality in fewer iterations as the number of parallel instances increased. Furthermore, speed performance was measured across three different hardware solutions - 16 core CPU, 68 core Xeon Phi and up to 4 Geforce GPUs. State of the art, ACO vectorisation techniques such as SS-Roulette were implemented using C++ and CUDA. Although excellent for routing simple TSPs, it was concluded that for complex real-world supply chain routing GPUs are not suitable due to meta-data access footprint required. Thus, our work demonstrates that the standard benchmarks are not suitable for generalised conclusions.

4.
IEEE Trans Syst Man Cybern B Cybern ; 36(5): 1024-43, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17036810

RESUMO

Evolvable hardware (EHW) refers to self-reconfiguration hardware design, where the configuration is under the control of an evolutionary algorithm (EA). One of the main difficulties in using EHW to solve real-world problems is scalability, which limits the size of the circuit that may be evolved. This paper outlines a new type of decomposition strategy for EHW, the "generalized disjunction decomposition" (GDD), which allows the evolution of large circuits. The proposed method has been extensively tested, not only with multipliers and parity bit problems traditionally used in the EHW community, but also with logic circuits taken from the Microelectronics Center of North Carolina (MCNC) benchmark library and randomly generated circuits. In order to achieve statistically relevant results, each analyzed logic circuit has been evolved 100 times, and the average of these results is presented and compared with other EHW techniques. This approach is necessary because of the probabilistic nature of EA; the same logic circuit may not be solved in the same way if tested several times. The proposed method has been examined in an extrinsic EHW system using the (1 + lambda) evolution strategy. The results obtained demonstrate that GDD significantly improves the evolution of logic circuits in terms of the number of generations, reduces computational time as it is able to reduce the required time for a single iteration of the EA, and enables the evolution of larger circuits never before evolved. In addition to the proposed method, a short overview of EHW systems together with the most recent applications in electrical circuit design is provided.


Assuntos
Algoritmos , Inteligência Artificial , Desenho Assistido por Computador , Desenho de Equipamento/métodos , Análise de Falha de Equipamento/métodos , Modelos Logísticos , Processamento de Sinais Assistido por Computador/instrumentação , Simulação por Computador
5.
Bioprocess Biosyst Eng ; 26(6): 353-9, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15378341

RESUMO

This contribution moves in the direction of answering some general questions about the most effective and useful ways of modelling bioprocesses. We investigate the characteristics of models that are good at extrapolating. We trained three fully predictive models with different representational structures (differential equations, differential equations with inheritance of rates and a network of reactions) on Saccharopolyspora erythraea shake flask fermentation data using genetic programming. The models were then tested on unseen data outside the range of the training data and the resulting performances were compared. It was found that constrained models with mathematical forms analogous to internal mass balancing and stoichiometric relations were superior to flexible unconstrained models, even though no a priori knowledge of this fermentation was used.


Assuntos
Inteligência Artificial , Glucose/metabolismo , Modelos Biológicos , Nitratos/metabolismo , Saccharopolyspora/fisiologia , Transdução de Sinais/fisiologia , Proliferação de Células , Simulação por Computador , Fermentação/fisiologia , Biologia de Sistemas/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...