Letteratura scientifica selezionata sul tema "Filtre H1"
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Articoli di riviste sul tema "Filtre H1"
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Syrneva, Aleksandra S., Vladimir V. Chesnokov e Dimitry V. Chesnokov. "Research on Terahertz Filters Employing the Effect of Frustrated Total Internal Reflection". Key Engineering Materials 437 (maggio 2010): 281–85. http://dx.doi.org/10.4028/www.scientific.net/kem.437.281.
Testo completoAbstract (sommario):
The optical filter under development employing frustrated total internal reflection is a micromechanical device containing two silicon rectangular prisms. There is flat silicon plane among hypotenuse edges of the prisms. The silicon plane is a Fabry-Perot resonator, with clearances h1 among the plate and prism edges being its mirrors. Theoretical resolution of the optical filter would be R ≈ 1,5∙103 if h1 = 50 µm and R ≈ 3∙105 if h1 = 100 µm with the thickness of the silicon plane being h = 65 µm; wavelength λ = 100 µm; free spectral region Δλ/λ ≈ 0,3…0,4, transmission in the maximum of spectral characteristics 0,6 (provided input and output silicon prism legs bloom).
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Cao, Huiliang, Yingjie Zhang, Chong Shen, Yu Liu e Xinwang Wang. "Temperature Energy Influence Compensation for MEMS Vibration Gyroscope Based on RBF NN-GA-KF Method". Shock and Vibration 2018 (2 dicembre 2018): 1–10. http://dx.doi.org/10.1155/2018/2830686.
Testo completoAbstract (sommario):
This paper proposed three methods to compensate the temperature energy influence drift of the MEMS vibration gyroscope, including radial basis function neural network (RBF NN), RBF NN based on genetic algorithm (GA), and RBF NN based on GA with Kalman filter (KF). Three-axis MEMS vibration gyroscope (Gyro X, Gyro Y, and Gyro Z) output data are compensated and analyzed in this paper. The experimental results proved the correctness of these three methods, and MEMS vibration gyroscope temperature energy influence drift is compensated effectively. The results indicate that, after RBF NN-GA-KF method compensation, the bias instability of Gyros X, Y, and Z improves from 139°/h, 154°/h, and 178°/h to 2.9°/h, 3.9°/h, and 1.6°/h, respectively. And the angle random walk of Gyros X, Y, and Z was improved from 3.03°/h1/2, 4.55°/h1/2, and 5.89°/h1/2to 1.58°/h1/2, 2.58°/h1/2, and 0.71°/h1/2, respectively, and the drift trend and noise characteristic are optimized obviously.
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Uribe-Murcia, Karen, e Yuriy S. Shmaliy. "UFIR Filtering Under Uncertain One-Step Delayed and Missing Data". WSEAS TRANSACTIONS ON SIGNAL PROCESSING 16 (19 febbraio 2021): 191–96. http://dx.doi.org/10.37394/232014.2020.16.21.
Testo completoAbstract (sommario):
This paper develops the unbiased finite impulse response (UFIR) filter for wireless sensor network (WSN) systems whose measurements are affected by random delays and packet dropout due to inescapable failures in the transmission and sensors. The Bernoulli distribution is used to model delays in arrived measurement data with known transmission probability. The effectiveness of the UFIR filter is compared experimentally to the KF and game theory recursive H1 filter in terms of accuracy and robustness employing the GPS-measured vehicle coordinates transmitted with latency over WSN.
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Fu, Yu Long, Xiao Long Xin e Jun Tao Wang. "State maps on semihoops". Open Mathematics 16, n. 1 (18 settembre 2018): 1061–76. http://dx.doi.org/10.1515/math-2018-0089.
Testo completoAbstract (sommario):
AbstractIn this paper, we introduce the notion of state maps from a semihoop H1 to another semihoop H2, which is a generalization of internal states (or state operators) on a semihoop H. Also we give a type of special state maps from a semihoop H1 to H1, which is called internal state maps (or IS-maps). Then we give some examples and basic properties of (internal) state maps on semihoops. Moreover, we discuss the relations between state maps and internal states on other algebras. Then we introduce several kinds of filters by state maps on semihoops, called SM-filters, state filters and dual state filters, respectively, and discuss the relations among them. Furthermore we introduce and study the notion of prime SM-filters on semihoops. Finally, using SM-filter, we characterize two kinds of state semihoops.
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López Sarmiento, Danilo Alfonso, Octavio Jose Salcedo Parra e René Geovani González Caballero. "EVALUACIÓN DEL DESEMPEÑO DE FILTRO ADAPTADO PARA RADIO COGNITIVA". Redes de Ingeniería 4, n. 2 (30 dicembre 2013): 16. http://dx.doi.org/10.14483/2248762x.5921.
Testo completoAbstract (sommario):
Este proyecto evalúa el rendimiento en la localización de filtros emparejados para la detección del espectro en Radio Cognitiva. Para resolver el problema del modelo de detección espectral se aplican dos hipótesis Ho y H1, las cuales generaron la probabilidad de detección (PD) y la probabilidad de falsa alarma (PFA) sobre una señal para un radio de ruido determinado (SNR). Se muestra como los filtros adaptados mantienen el rendimiento y el cumplimiento de los requisitos establecidos por el IEEE 802.22 en los cambios en la PFA y la potencia del ruido.
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Marquez-Figueroa, Sandra, Yuriy S. Shmaliy e Oscar Ibarra-Manzano. "Improving Gaussianity of EMG Envelope for Myoelectric Robot Arm Control". WSEAS TRANSACTIONS ON BIOLOGY AND BIOMEDICINE 18 (5 agosto 2021): 106–12. http://dx.doi.org/10.37394/23208.2021.18.12.
Testo completoAbstract (sommario):
Several methods have been developed in biomedical signal processing to extract the envelope and features of electromyography (EMG) signals and predict human motion. Also, efforts were made to use this information to improve the interaction of a human body and artificial protheses. The main operations here are envelope acquiring, artifacts filtering, estimate smoothing, EMG value standardizing, feature classifying, and motion recognizing. In this paper, we employ EMG data to extract the envelope with a highest Gaussianity using the rectified signal, where we deal with the absolute EMG signals so that all values become positive. First, we remove artifacts from EMG data by using filters such as the Kalman filter (KF), H1 filter, unbiased finite impulse response (UFIR) filter, and the cKF, cH1 filter, and cUFIR filter modified for colored measurement noise. Next, we standardize the EMG envelope and improve the Gaussianity. Finally, we extract the EMG signal features to provide an accurate prediction.
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Smith, Vivianne C., Joel Pokorny, Barry B. Lee e Dennis M. Dacey. "Primate Horizontal Cell Dynamics: An Analysis of Sensitivity Regulation in the Outer Retina". Journal of Neurophysiology 85, n. 2 (1 febbraio 2001): 545–58. http://dx.doi.org/10.1152/jn.2001.85.2.545.
Testo completoAbstract (sommario):
The human cone visual system maintains sensitivity over a broad range of illumination, from below 1 troland to 1,000,000 trolands. While the cone photoreceptors themselves are an important locus for sensitivity regulation—or light adaptation—the degree to which they contribute in primates remains unclear. To determine the range of sensitivity regulation in the outer retina, the temporal dynamics, neural gain control, and response range compression were measured in second-order neurons, the H1 horizontal cells, of the macaque retina. Situated at the first synapse in the retina, H1 cells receive input from a large population of cones. Lee et al. have previously shown that sensitivity regulation in H1 cells is both cone type-specific and spatially restricted. The sensitivity regulation seen in H1 cells at moderate illuminances thus takes place before the summation of cone signals in these cells, and the data establish the H1 cell as a convenient locus for analyzing cone signals. In the present study, cone-driven responses of primate H1 cells to temporally modulated sine-wave stimuli and to increment pulses were measured at steady levels of 1–1,000 trolands. The H1 cell gave a modulated response to sine-wave stimuli and hyperpolarized to increment pulses with overshoots at stimulus onset and offset. The temporal amplitude sensitivity function was primarily low-pass in shape, with a small degree of low-frequency roll off and a resonance shoulder near 40 Hz. A model incorporating a cascade of first-order filters together with an underdamped second-order filter could describe both temporal sinusoidal and pulse hyperpolarizations. Amplitude sensitivity was estimated from both pulse and sine-wave data as a function of the steady adaptation level. Sensitivity at low light levels (1 troland) showed a slowing in temporal dynamics, indicating time-dependent sensitivity regulation. Sensitivity was reduced at light levels above approximately 10 trolands, reflecting both response range compression and neural gain control. Thus the outer retina is a major locus for sensitivity regulation in primates.
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Liu, Siru, Kensaku Kawamoto, Guilherme Del Fiol, Charlene Weir, Daniel C. Malone, Thomas J. Reese, Keaton Morgan, David ElHalta e Samir Abdelrahman. "The potential for leveraging machine learning to filter medication alerts". Journal of the American Medical Informatics Association 29, n. 5 (5 gennaio 2022): 891–99. http://dx.doi.org/10.1093/jamia/ocab292.
Testo completoAbstract (sommario):
Abstract Objective To evaluate the potential for machine learning to predict medication alerts that might be ignored by a user, and intelligently filter out those alerts from the user’s view. Materials and Methods We identified features (eg, patient and provider characteristics) proposed to modulate user responses to medication alerts through the literature; these features were then refined through expert review. Models were developed using rule-based and machine learning techniques (logistic regression, random forest, support vector machine, neural network, and LightGBM). We collected log data on alerts shown to users throughout 2019 at University of Utah Health. We sought to maximize precision while maintaining a false-negative rate <0.01, a threshold predefined through discussion with physicians and pharmacists. We developed models while maintaining a sensitivity of 0.99. Two null hypotheses were developed: H1—there is no difference in precision among prediction models; and H2—the removal of any feature category does not change precision. Results A total of 3,481,634 medication alerts with 751 features were evaluated. With sensitivity fixed at 0.99, LightGBM achieved the highest precision of 0.192 and less than 0.01 for the pre-defined maximal false-negative rate by subject-matter experts (H1) (P < 0.001). This model could reduce alert volume by 54.1%. We removed different combinations of features (H2) and found that not all features significantly contributed to precision. Removing medication order features (eg, dosage) most significantly decreased precision (−0.147, P = 0.001). Conclusions Machine learning potentially enables the intelligent filtering of medication alerts.
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Liu, Hai, Maiying Zhong e Rui Yang. "Simultaneous Disturbance Compensation and H1/H∞ Optimization In Fault Detection Of UAVs". International Journal of Applied Mathematics and Computer Science 28, n. 2 (1 giugno 2018): 349–62. http://dx.doi.org/10.2478/amcs-2018-0026.
Testo completoAbstract (sommario):
Abstract This paper deals with the problem of robust fault detection (FD) for an unmanned aerial vehicle (UAV) flight control system (FCS). A nonlinear model to describe the UAV longitudinal motions is introduced, in which multiple sources of disturbances include wind effects, modeling errors and sensor noises are classified into groups. Then the FD problem is formulated as fault detection filter (FDF) design for a kind of nonlinear discrete time varying systems subject to multiple disturbances. In order to achieve robust FD performance against multiple disturbances, simultaneous disturbance compensation and H1/H∞ optimization are carried out in designing the FDF. The optimality of the proposed FDF is shown in detail. Finally, both simulations and real flight data are applied to validate the proposed method. An improvement of FD performance is achieved compared with the conventional H1/H∞-FDF.
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Abotaleb, Mostafa, Janusz Mindykowski, Boleslaw Dudojć e Romuald Maśnicki. "Simulation of Foundation Fieldbus Manchester Coded 31.25 kbps H1 Bus Using MATLAB and Simulink". Scientific Journal of Gdynia Maritime University, n. 123 (30 settembre 2022): 18–31. http://dx.doi.org/10.26408/123.02.
Testo completoAbstract (sommario):
The purpose of this article is to provide an understanding of possible techniques through which a H1 31.25 kbps Foundation Fieldbus Manchester coded signal can be modulated or demodulated. This understanding will be rendered through MATLAB and SIMULINK models, simulating both ideal and practical as well as noiseless and noisy conditions during the modulation/demodulation process. The simulation models will differentiate between the modulation methods adopted to generate ideal rectangular as well as practical trapezoidal waveforms for the Manchester coded signal. The analysis of the simulation results will describe the mechanisms through which distortion induced by additive white Gaussian noise can be eliminated during the demodulation process either by using recursive filters, such as a Kalman filter, or by calculating wave energy levels in specific time intervals.
Tesi sul tema "Filtre H1"
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Mohammedi, Irryhl. "Contribution à l’estimation robuste par intervalle des systèmes multivariables LTI et LPV : Application aux systèmes aérospatiaux". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0142.
Testo completoAbstract (sommario):
Les travaux présentés dans ce mémoire de thèse visent à développer de nouvelles approches basées sur une nouvelle classe particulière d’estimateurs d´état : les filtres dits par intervalles. Tout comme la classe des observateurs intervalles, l’objectif est d’estimer les bornes supérieures et inférieures des états d’un système, à chaque instant de temps. L’approche proposée repose sur la théorie des systèmes monotones et sur la connaissance a priori du domaine d’appartenance, supposé borné, des incertitudes de modèle et des entrées exogènes (perturbations, bruit de mesure, etc). L’élément clé de l’approche proposée repose sur l’utilisation de filtre d’ordre quelconque, sans structure a priori fixée, plutôt qu’une structure basée sur l’observateur (reposant uniquement sur une structure dynamique du système étudié). La synthèse des paramètres du filtre repose sur la résolution d’un problème d’optimisation sous contraintes de type inégalités matricielles linéaires et bilinéaires (LMI et BMI) permettant de garantir simultanément les conditions d’existence du filtre ainsi qu’un niveau de performance, soit dans un contexte énergie, soit dans un contexte amplitude ou soit dans un contexte mixte énergie/amplitude. La méthodologie de synthèse proposée est illustrée sur un exemple académique et est comparée avec d’autres méthodes existantes dans la littérature. Enfin, la méthodologie est appliquée au cas du contrôle d’attitude et d’orbite d’un satellite, sous des conditions de simulations réalistesThe work of this thesis aims at developing new approaches based on a new particular class of state estimators, the so-called interval or ensemble filters.Like the class of interval observers, the objective is to estimate, in a guaranteed way, the upper and lower bounds of the states of a system, at each time instant.The proposed approach is based on the theory of monotonic systems and on the knowledge of the domain of membership, supposedly bounded, of the uncertainties of the system, such as disturbances, noise and bias of sensors, etc.The key element of the proposed approach is to use a filter structure advantage, rather than an observer-based structure (relying only on a dynamic structure of the studied system).The synthesis of the filter parameters is based on the resolution of a constrained optimization problem of linear and bilinear matrix inequalities (LMI and BMI) allowing to guarantee simultaneously the existence conditions of the filter as well as a performance level, either in an energy context for LTI systems, or in an amplitude context or in a mixed energy/amplitude context for LPV systemsThe proposed synthesis methodology is illustrated on an academic example and is compared with other existing methods in the literature. Finally, the methodology is applied to the case of attitude and acceleration control of a satellite, under realistic simulation conditions
Atti di convegni sul tema "Filtre H1"
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J. de Oliveira, Bárbara, Víctor C. S. Campos e Márcio F. Braga. "Estimação de Estados de uma Câmara Termoeletricamente Controlada utilizando Projetos de Filtros H1". In Congresso Brasileiro de Automática - 2020. sbabra, 2020. http://dx.doi.org/10.48011/asba.v2i1.1748.
Testo completoAbstract (sommario):
O objetivo deste trabalho é apresentar e comparar duas estratégias de filtros para estimação de estados aplicados em uma Câmara Termoeletricamente Controlada (CTC). A CTC é composta por cinco sensores digitais de temperatura que representam os estados do sistema. A aplicação dos métodos é executada em duas etapas. Na primeira etapa, os filtros são implementados de forma off-line no software MATLAB R2018a, a partir dos dados reais do sistema. Enquanto, na segunda etapa, os filtros são aplicados em tempo real no sistema físico. São apresentados dois teoremas para a obtenção dos parâmetros dos filtros robustos tendo como base o lema de Finsler e o bounded real lemma, utilizando a norma Hinf como critério de desempenho, uma vez que emprega-se um modelo politópico incerto para descrever a dinâmica da CTC. O problema de filtragem ótima para o sistema é resolvido por meio de Desigualdades Matriciais Lineares. Os resultados obtidos pelos dois métodos são comparados graficamente e por meio da métrica do Erro Quadrático Médio.