Letteratura scientifica selezionata sul tema "Filtre intervalle"
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Articoli di riviste sul tema "Filtre intervalle"
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Scherman, Mathieu. "Travail et conscience : la présentation de soi dans les estimi de Trévise du XVe siècle." Mélanges de l École française de Rome Moyen Âge 118, no. 1 (2006): 127–48. http://dx.doi.org/10.3406/mefr.2006.9408.
Testo completoAbstract (sommario):
Comment le travail intervient-il dans l’identité d’une population urbaine à la fin du Moyen Âge ? À partir des déclarations fiscales rédigées à intervalles réguliers par les contribuables de la ville de Trévise, il est possible de s’interroger sur la valeur qu’ils attribuent au travail dans leur identification. Voulue par le pouvoir, la déclaration n’en est pas moins un document personnel par lequel l’individu s’exprime. Le filtre du rédacteur a peu d’incidence, voire aucune, sur le contenu du document. La population recensée grâce aux opérations fiscales est large, ce qui permet d’examiner l’ensemble de la population (femmes, nobles, riches marchands ou artisans, dépendants ou indépendants). Le travail n’a pas la même incidence sur tous les individus mais, pour la majorité de la population urbaine, il est un paramètre fondamental de l’identité.
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Xin Lingyi, 忻伶怡, 周雪芳 Zhou Xuefang, 毕美华 Bi Meihua та ін. "通道间隔可切换的双Lyot滤波器的结构设计与性能分析". Chinese Journal of Lasers 49, № 21 (2022): 2106002. http://dx.doi.org/10.3788/cjl202249.2106002.
Testo completo
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Hicks, Hilary, Alex Laffer, Genna Losinski, and Amber Watts. "Low Frequency Extension Filter and ActiGraph-Calculated Sleep Intervals in Older Adults." Innovation in Aging 4, Supplement_1 (2020): 428. http://dx.doi.org/10.1093/geroni/igaa057.1381.
Testo completoAbstract (sommario):
Abstract Actigraphy has become a popular, non-invasive means of continuously monitoring physical activity and sleep. One optional setting, the low frequency extension (LFE) filter, reduces the movement threshold to capture low acceleration activity that is common in older adults. This filter significantly alters physical activity outcomes (e.g., step counts), but it is unclear if this has implications for sleep interval calculations that rely upon accurate differentiation between physical activity and sleep. We investigated the effects of the LFE filter on wrist-worn sleep estimates in older adults. Participants were 9 older adults who wore the ActiGraph GT9X on their non-dominant wrist for 7 days in a free-living environment. Raw data was processed with and without the LFE filter enabled, and sleep intervals were calculated by a proprietary ActiGraph algorithm. Paired samples t-tests demonstrated that the LFE filter generated significantly later bedtimes, fewer minutes spent in bed, shorter sleep duration, and fewer awakenings during the night compared to when the filter was disabled (all p < .043). Use of the LFE filter did not lead to differences in arise time, sleep latency, efficiency, or wake after sleep onset (all p > .052). While the LFE filter was designed to improve accuracy of physical activity estimates in more sedentary populations, these findings suggest that the LFE filter also has the potential to impact sleep estimates of older adults. Researchers using ActiGraph-calculated sleep would benefit from careful consideration of this software-dependent impact.
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Chen, Feng-Wu, Ning-Yuan Lue, Mei-Yin Chou, and Yu-Shu G. Wu. "All-electrical valley filtering in graphene systems. I. A path to integrated electro-valleytronics." Journal of Applied Physics 132, no. 16 (2022): 164303. http://dx.doi.org/10.1063/5.0114386.
Testo completoAbstract (sommario):
Probing and controlling the valley degree of freedom in graphene systems by transport measurements has been a major challenge to fully exploit the unique properties of this two-dimensional material. In this theoretical work, we show that this goal can be achieved by a quantum-wire geometry made of gapped graphene that acts as a valley filter with the following favorable features: (i) all electrical gate control, (ii) electrically switchable valley polarity, (iii) robustness against configuration fluctuation, and (iv) potential for room temperature operation. This valley filtering is accomplished by a combination of gap opening in either bilayer graphene with a vertical electrical field or single layer graphene on h-BN, valley splitting with a horizontal electric field, and intervalley mixing by defect scattering. In addition to functioning as a building block for valleytronics, the proposed configuration makes it possible to convert signals between electrical and valleytronic forms, thus allowing for the integration of electronic and valleytronic components for the realization of electro-valleytronics.
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Oliveira, Danian Steinkirch de, Paulo Eduardo Miranda Cunha, Luiz Gallisa Guimaraes, and Andre Fabiano Steklain. "High-Resolution Ray Tracing Migration." Brazilian Journal of Geophysics 39, no. 4 (2021): 521. http://dx.doi.org/10.22564/rbgf.v39i4.2112.
Testo completoAbstract (sommario):
ABSTRACT. We present a seismic migration algorithm that calculates travel times and amplitudes based on the paraxial extrapolation of the dynamic ray tracing. We use a target-oriented approach with automatic selection of migration parameters and seismic traces that will compose the image. By associating the ray parameter (slowness vector) with the amplitudes of the seismic data, we reach a new form of migration amplitude conditioner that acts as a filter and may increase the resolution of reflectors and faults. On the other hand, when using the seismic amplitudes as weights, we can estimate the slowness vectors associated with the true seismic reflectors in depth. We apply this method to the synthetic seismic data of the Marmousi velocity model. When comparing the migrated seismic section to the true interval velocity model, we can see a precise matching of the geological features in a high-resolution pattern.Keywords: seismic migration, target-orientation, dynamic ray tracing, paraxial amplitude extrapolation. Migração por Traçado de Raios de Alta ResoluçãoRESUMO. Apresentamos um algoritmo de migração sísmica que calcula tempos e amplitudes de viagem com base na extrapolação paraxial do traçado dinâmico de raios. Utilizamos uma abordagem orientada a alvos com seleção automática dos parâmetros de migração e dos traços sísmicos que irão compor a imagem. Ao associar o parâmetro de raio (vetor de vagarosidade) às amplitudes dos dados sísmicos, chegamos a uma nova forma de condicionador de amplitudes de migração que atua como filtro e pode aumentar a resolução de refletores e falhas. Por outro lado, ao usar as amplitudes sísmicas como pesos, podemos estimar os vetores de vagarosidade associados aos verdadeiros refletores sísmicos em profundidade. Aplicamos este método aos dados sísmicos sintéticos do modelo de velocidade de Marmousi. Ao comparar a seção sísmica migrada com o modelo de velocidades intervalar verdadeiro, podemos ver uma correspondência precisa das feições geológicas em um padrão de alta resolução.Palavras-chave: migração sísmica, orientação ao alvo, traçado dinâmico de raios, extrapolação paraxial de amplitude.
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Klinke, Rainer, Marcus Müller, Claus-Peter Richter, and Jean Smolders. "Preferred intervals in birds and mammals: A filter response to noise?" Hearing Research 74, no. 1-2 (1994): 238–46. http://dx.doi.org/10.1016/0378-5955(94)90192-9.
Testo completo
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COLAK, OMER H. "AN EFFICIENT METHOD FOR CORRECTION OF ECTOPIC BEATS IN R-R INTERVALS." Fluctuation and Noise Letters 08, no. 03n04 (2008): L359—L368. http://dx.doi.org/10.1142/s0219477508005112.
Testo completoAbstract (sommario):
This study presents an efficient method based on principal component analysis (PCA) to remove ectopic beats in R-R intervals. The method is focused on variation of slopes at each time steps and reconstruction of new time values using initial eigenvectors and new slope values. Obtained results and LF (low frequency) and HF (high frequency) energy distributions were compared with outputs of integral pulse frequency modulation (IPFM) method and sliding window average filter (SWAF).
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Yost, William A., Dan Mapes-Riordan, Raymond Dye, Stanley Sheft, and William Shofner. "Discrimination of first- and second-order regular intervals from random intervals as a function of high-pass filter cutoff frequency." Journal of the Acoustical Society of America 117, no. 1 (2005): 59–62. http://dx.doi.org/10.1121/1.1830671.
Testo completo
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Ashkenazy, Y., M. Lewkowicz, J. Levitan, H. Moelgaard, P. E. Bloch Thomsen, and K. Saermark. "Discrimination of the Healthy and Sick Cardiac Autonomic Nervous System by a New Wavelet Analysis of Heartbeat Intervals." Fractals 06, no. 03 (1998): 197–203. http://dx.doi.org/10.1142/s0218348x98000249.
Testo completoAbstract (sommario):
We demonstrate that it is possible to distinguish with a complete certainty between healthy subjects and patients with various dysfunctions of the cardiac nervous system by way of multiresolutional wavelet transform of RR intervals. We repeated the study of Thurner et al. on different ensemble of subjects. We show that reconstructed series using a filter which discards wavelet coefficient related with higher scales enables one to classify individuals for which the method otherwise is inconclusive. We suggest a delimiting diagnostic value of the standard deviation of the filtered, reconstructed RR interval time series in the range of ~ 0.035 (for the above mentioned filter), below which individuals are at risk.
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Xu, XueQing, and YongHong Zhou. "EOP prediction using least square fitting and autoregressive filter over optimized data intervals." Advances in Space Research 56, no. 10 (2015): 2248–53. http://dx.doi.org/10.1016/j.asr.2015.08.007.
Testo completoTesi sul tema "Filtre intervalle"
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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 réalistes<br>The 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
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Tran, Tuan Anh. "Cadre unifié pour la modélisation des incertitudes statistiques et bornées : application à la détection et isolation de défauts dans les systèmes dynamiques incertains par estimation." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30292/document.
Testo completoAbstract (sommario):
Cette thèse porte sur l'estimation d'état des systèmes dynamiques à temps discret dans le contexte de l'intégration d'incertitudes statistiques et à erreurs bornées. Partant du filtre de Kalman intervalle (IKF) et de son amélioration (iIKF), nous proposons un algorithme de filtrage pour des systèmes linéaires dont les bruits sont gaussiens incertains, c'est-à-dire de moyenne et matrice de covariance définies par leur appartenance à des intervalles. Ce nouveau filtre de Kalman intervalle (UBIKF) repose sur la recherche d'une matrice de gain ponctuelle minimisant une borne majorante de l'ensemble des matrices de covariance de l'erreur d'estimation en respectant les bornes des incertitudes paramétriques. Un encadrement de tousles estimés possibles est ensuite déterminé en utilisant l'analyse par intervalles. Le filtre UBIKF permet de réduire à la fois la complexité calculatoire de l'inversion ensembliste des matrices intervalles présent dans le filtre iIKF et le conservatisme des estimations. Nous abordons ensuite différents cadres permettant de représenter des connaissances incomplètes ou imprécises, y compris les fonctions de répartition, la théorie de possibilité et la théorie des fonctions de croyance. Grâce à cette dernière, un modèle sous forme d'une fonction de masse pour une distribution gaussienne multivariée incertaine est proposé. Un filtrage particulaire ensembliste basé sur cette théorie est développé pour des systèmes dynamiques non linéaires dans lesquels les bruits sur la dynamique sont bornés et les erreurs de mesure sont modélisées par une fonction de masse gaussienne incertaine. Enfin, le filtre UBIKF est utilisé pour la détection et l'isolation de défauts en mettant en œuvre le schéma d'observateurs généralisé et l'analyse structurelle. Au travers de différents exemples, la capacité d'isolation de défauts capteurs/actionneurs de cet outil est illustrée et comparée à d'autre approches<br>This thesis deals with state estimation in discrete-time dynamic systems in the context of the integration of statistical and bounded error uncertainties. Motivated by the drawbacks of the interval Kalman filter (IKF) and its improvement (iIKF), we propose a filtering algorithm for linear systems subject to uncertain Gaussian noises, i.e. with the mean and covariance matrix defined by their membership to intervals. This new interval Kalman filter (UBIKF) relies on finding a punctual gain matrix minimizing an upper bound of the set of estimation error covariance matrices by respecting the bounds of the parametric uncertainties. An envelope containing all possible estimates is then determined using interval analysis. The UBIKF reduces not only the computational complexity of the set inversion of the matrices intervals appearing in the iIKF, but also the conservatism of the estimates. We then discuss different frameworks for representing incomplete or imprecise knowledge, including the cumulative distribution functions, the possibility theory and the theory of belief functions. Thanks to the last, a model in the form of a mass function for an uncertain multivariate Gaussian distribution is proposed. A box particle filter based on this theory is developed for non-linear dynamic systems in which the process noises are bounded and the measurement errors are represented by an uncertain Gaussian mass function. Finally, the UBIKF is applied to fault detection and isolation by implementing the generalized observer scheme and structural analysis. Through various examples, the capacity for detecting and isolating sensor/actuator faults of this tool is illustrated and compared to other approaches
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Pepy, Romain. "Vers une planification robuste et sûre pour les systèmes autonomes." Phd thesis, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00845477.
Testo completoAbstract (sommario):
De nombreux outils existent pour résoudre les problèmes de planification sous contraintes. On peut les regrouper en deux classes principales. Les plus anciens planificateurs utilisent une discrétisation préalable de l'espace d'état. Les plus récents, les planificateurs à échantillonnage, permettent une exploration plus efficace. Ces planificateurs sont utilisés dans de nombreux domaines, comme la chimie, la biologie, la robotique, l'automatique ou encore l'intelligence artificielle. La contribution majeure de nos travaux est d'apporter une réponse au problème de planification de trajectoires en présence d'incertitudes en associant une technique de planification moderne, permettant une exploration rapide de l'espace d'état à des méthodes de localisation permettant de caractériser l'incertitude sur l'état du système à un instant donné. Deux approches ont été suivies. Dans la première, le planificateur utilise une représentation probabiliste de l'état du système à un instant donné, par une densité de probabilité gaussienne. La propagation des erreurs est effectuée en utilisant un filtre de Kalman étendu. Dans la deuxième approche, nous englobons dans un ensemble calculable les états que peut prendre le système à un instant donné compte tenu de bornes sur les erreurs commises. Contrairement à l'approche probabiliste précédente, cette approche permet de fournir une garantie sur la sûreté du système, à condition bien sûr que les hypothèses sur les bruits d'états qui la fondent soient satisfaites.
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Nicola, Jérémy. "Robust, precise and reliable simultaneous localization and mapping for and underwater robot. Comparison and combination of probabilistic and set-membership methods for the SLAM problem." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0066/document.
Testo completoAbstract (sommario):
Dans cette thèse on s'intéresse au problème de la localisation d'un robot sous-marin et de la cartographie en simultané d'un jeu de balises acoustiques installées sur le fond marin, en utilisant un distance-mètre acoustique et une centrale inertielle. Nous nous focalisons sur les deux approches principales utilisées pour résoudre ce type de problème: le filtrage de Kalman et le filtrage ensembliste basé sur l'analyse par intervalles. Le filtre de Kalman est optimal quand les équations d'état du robot sont linéaires et les bruits sont additifs, Gaussiens. Le filtrage par intervalles ne modélise pas les incertitudes dans un cadre probabiliste, et ne fait qu'une seule hypothèse sur leur nature: elles sont bornées. De plus, l'approche utilisant les intervalles permet la propagation rigoureuse des incertitudes, même quand les équations sont non linéaires. Cela résulte en une estimation hautement fiable, au prix d'une précision réduite. Nous montrons que dans un contexte sous-marin, quand le robot est équipé avec une centrale inertielle de haute précision, une partie des équations du SLAM peut raisonnablement être considérée comme linéaire avec un bruit Gaussien additif, en faisant le terrain de jeu idéal d'un filtre de Kalman. De l'autre côté, les équations liées aux observations du distance-mètre acoustique sont bien plus problématiques: le système n'est pas observable, les équations sont non linéaires, et les outliers sont fréquents. Ces conditions sont idéales pour une approche à erreur bornées basée sur l'analyse par intervalles. En prenant avantage des propriétés des bruits Gaussiens, cette thèse réconcilie le traitement probabiliste et ensembliste des incertitudes pour les systèmes aussi bien linéaires que non linéaires sujets à des bruits Gaussiens additifs. En raisonnant de manière géométrique, nous sommes capables d'exprimer la partie des équations du filtre de Kalman modélisant la dynamique du véhicule dans un cadre ensembliste. De la même manière, un traitement plus rigoureux et précis des incertitudes est décrit pour la partie des équations du filtre de Kalman liée aux mesures de distances. Ces outils peuvent ensuite être combinés pour obtenir un algorithme de SLAM qui est fiable, précis et robuste. Certaines des méthodes développées dans cette thèse sont illustrées sur des données réelles<br>In this thesis, we work on the problem of simultaneously localizing an underwater robot while mapping a set of acoustic beacons lying on the seafloor, using an acoustic range-meter and an inertial navigation system. We focus on the two main approaches classically used to solve this type of problem: Kalman filtering and set-membership filtering using interval analysis. The Kalman filter is optimal when the state equations of the robot are linear, and the noises are additive, white and Gaussian. The interval-based filter do not model uncertainties in a probabilistic framework, and makes only one assumption about their nature: they are bounded. Moreover, the interval-based approach allows to rigorously propagate the uncertainties, even when the equations are non-linear. This results in a high reliability in the set estimate, at the cost of a reduced precision.We show that in a subsea context, when the robot is equipped with a high precision inertial navigation system, a part of the SLAM equations can reasonably be seen as linear with additive Gaussian noise, making it the ideal playground of a Kalman filter. On the other hand, the equations related to the acoustic range-meter are much more problematic: the system is not observable, the equations are non-linear, and the outliers are frequent. These conditions are ideal for a set-based approach using interval analysis.By taking advantage of the properties of Gaussian noises, this thesis reconciles the probabilistic and set-membership processing of uncertainties for both linear and non-linear systems with additive Gaussian noises. By reasoning geometrically, we are able to express the part of the Kalman filter equations linked to the dynamics of the vehicle in a set-membership context. In the same way, a more rigorous and precise treatment of uncertainties is described for the part of the Kalman filter linked to the range-measurements. These two tools can then be combined to obtain a SLAM algorithm that is reliable, precise and robust. Some of the methods developed during this thesis are demonstrated on real data
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Akhbari, Mahsa. "Analyse des intervalles ECG inter- et intra-battement sur des modèles d'espace d'état et de Markov cachés." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT026.
Testo completoAbstract (sommario):
Les maladies cardiovasculaires sont l'une des principales causes de mortalité chez l'homme. Une façon de diagnostiquer des maladies cardiaques et des anomalies est le traitement de signaux cardiaques tels que le ECG. Dans beaucoup de ces traitements, des caractéristiques inter-battements et intra-battements de signaux ECG doivent être extraites. Ces caractéristiques comprennent les points de repère des ondes de l’ECG (leur début, leur fin et leur point de pic), les intervalles significatifs et les segments qui peuvent être définis pour le signal ECG. L'extraction des points de référence de l'ECG consiste à identifier l'emplacement du pic, de début et de la fin de l'onde P, du complexe QRS et de l'onde T. Ces points véhiculent des informations cliniquement utiles, mais la segmentation precise de chaque battement de l'ECG est une tâche difficile, même pour les cardiologues expérimentés.Dans cette thèse, nous utilisons un cadre bayésien basé sur le modèle dynamique d'ECG proposé par McSharry. Depuis ce modèle s'appuyant sur la morphologie des ECG, il peut être utile pour la segmentation et l'analyse d'intervalles d'ECG. Afin de tenir compte de la séquentialité des ondes P, QRS et T, nous utiliserons également l'approche de Markov et des modèles de Markov cachés (MMC). En bref dans cette thèse, nous utilisons un modèle dynamique (filtre de Kalman), un modèle séquentiel (MMC) et leur combinaison (commutation de filtres de Kalman (SKF)). Nous proposons trois méthodes à base de filtres de Kalman, une méthode basée sur les MMC et un procédé à base de SKF. Nous utilisons les méthodes proposées pour l'extraction de points de référence et l'analyse d'intervalles des ECG. Le méthodes basées sur le filtrage de Kalman sont également utilisés pour le débruitage d'ECG, la détection de l'alternation de l'onde T, et la détection du pic R de l'ECG du foetus.Pour évaluer les performances des méthodes proposées pour l'extraction des points de référence de l'ECG, nous utilisons la base de données "Physionet QT", et une base de données "Swine" qui comprennent ECG annotations de signaux par les médecins. Pour le débruitage d'ECG, nous utilisons les bases de données "MIT-BIH Normal Sinus Rhythm", "MIT-BIH Arrhythmia" et "MIT-BIH noise stress test". La base de données "TWA Challenge 2008 database" est utilisée pour la détection de l'alternation de l'onde T. Enfin, la base de données "Physionet Computing in Cardiology Challenge 2013 database" est utilisée pour la détection du pic R de l'ECG du feotus. Pour l'extraction de points de reference, la performance des méthodes proposées sont évaluées en termes de moyenne, écart-type et l'erreur quadratique moyenne (EQM). Nous calculons aussi la sensibilité des méthodes. Pour le débruitage d'ECG, nous comparons les méthodes en terme d'amélioration du rapport signal à bruit<br>Cardiovascular diseases are one of the major causes of mortality in humans. One way to diagnose heart diseases and abnormalities is processing of cardiac signals such as ECG. In many of these processes, inter-beat and intra-beat features of ECG signal must be extracted. These features include peak, onset and offset of ECG waves, meaningful intervals and segments that can be defined for ECG signal. ECG fiducial point (FP) extraction refers to identifying the location of the peak as well as the onset and offset of the P-wave, QRS complex and T-wave which convey clinically useful information. However, the precise segmentation of each ECG beat is a difficult task, even for experienced cardiologists.In this thesis, we use a Bayesian framework based on the McSharry ECG dynamical model for ECG FP extraction. Since this framework is based on the morphology of ECG waves, it can be useful for ECG segmentation and interval analysis. In order to consider the time sequential property of ECG signal, we also use the Markovian approach and hidden Markov models (HMM). In brief in this thesis, we use dynamic model (Kalman filter), sequential model (HMM) and their combination (switching Kalman filter (SKF)). We propose three Kalman-based methods, an HMM-based method and a SKF-based method. We use the proposed methods for ECG FP extraction and ECG interval analysis. Kalman-based methods are also used for ECG denoising, T-wave alternans (TWA) detection and fetal ECG R-peak detection.To evaluate the performance of proposed methods for ECG FP extraction, we use the "Physionet QT database", and a "Swine ECG database" that include ECG signal annotations by physicians. For ECG denoising, we use the "MIT-BIH Normal Sinus Rhythm", "MIT-BIH Arrhythmia" and "MIT-BIH noise stress test" databases. "TWA Challenge 2008 database" is used for TWA detection and finally, "Physionet Computing in Cardiology Challenge 2013 database" is used for R-peak detection of fetal ECG. In ECG FP extraction, the performance of the proposed methods are evaluated in terms of mean, standard deviation and root mean square of error. We also calculate the Sensitivity for methods. For ECG denoising, we compare methods in their obtained SNR improvement
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Dandach, Hoda. "Prédiction de l'espace navigable par l'approche ensembliste pour un véhicule routier." Thesis, Compiègne, 2014. http://www.theses.fr/2014COMP1892/document.
Testo completoAbstract (sommario):
Les travaux de cette thèse porte sur le calcul d’un espace d’état navigable d’un véhicule routier, ainsi que sur l’observation et l’estimation de son état, à l’aide des méthodes ensemblistes par intervalles. Dans la première partie de la thèse, nous nous intéressons aux problèmes d’estimation d’état relevant de la dynamique du véhicule. Classiquement, l’estimation se fait en utilisant le filtrage de Kalman pour des problèmes d’estimation linéaires ou le filtrage de Kalman étendu pour les cas non-linéaires. Ces filtres supposent que les erreurs sur le modèle et sur les mesures sont blanches et gaussiennes. D’autre part, les filtres particulaires (PF), aussi connus comme Méthodes de Monte-Carlo séquentielles, constituent souvent une alternative aux filtres de Kalman étendus. Par contre, les performances des filtres PF dépendent surtout du nombre de particules utilisées pour l’estimation, et sont souvent affectées par les bruits de mesures aberrants. Ainsi, l’objectif principal de cette partie de travail est d’utiliser une des méthodes à erreurs bornées, qui est le filtrage par boites particulaires (Box Particle Filter (BPF)), pour répondre à ces problèmes. Cette méthode généralise le filtrage particulaire à l’aide des boites remplaçant les particules. A l’aide de l’analyse par intervalles, l’estimation de certains variables fortement reliées à la dynamique du véhicule comme le transfert de charge latérale, le roulis et la vitesse de roulis est donnée, à chaque instant, sous forme d’un intervalle contenant la vraie valeur simulée. Dans la deuxième partie de la thèse, une nouvelle formalisation du problème de calcul de l’espace navigable de l’état d’un véhicule routier est présentée. Un algorithme de résolution est construit, basé sur le principe de l’inversion ensembliste par intervalles et sur la satisfaction des contraintes. Nous cherchons à caractériser l’ensemble des valeurs de la vitesse longitudinale et la dérive au centre de gravité qui correspondent à un comportement stable du véhicule : pas de renversement ni dérapage. Pour décrire le risque de renversement, nous avons utilisé l’indicateur de transfert de charge latéral (LTR). Pour décrire le risque de dérapage, nous avons utilisé les dérives des roues. Toutes les variables sont liées géométriquement avec le vecteur d’état choisi. En utilisant ces relations, l’inversion ensembliste par intervalles est appliquée afin de trouver l’espace navigable de l’état tel que ces deux risques sont évités. L’algorithme Sivia est implémenté, approximant ainsi cet espace. Une vitesse maximale autorisée au véhicule est déduite. Elle est associée à un angle de braquage donné sur une trajectoire connue<br>In this thesis, we aim to characterize a vehicle stable state domain, as well as vehicle state estimation, using interval methods.In the first part of this thesis, we are interested in the intelligent vehicle state estimation.The Bayesian approach is one of the most popular and used approaches of estimation. It is based on the calculated probability of the density function which is neither evident nor simple all the time, conditioned on the available measurements.Among the Bayesian approaches, we know the Kalman filter (KF) in its three forms(linear, non linear and unscented). All the Kalman filters assume unimodal Gaussian state and measurement distributions. As an alternative, the Particle Filter(PF) is a sequential Monte Carlo Bayesian estimator. Contrary to Kalman filter,PF is supposed to give more information about the posterior even when it has a multimodal shape or when the noise follows non-Gaussian distribution. However,the PF is very sensitive to the imprecision due by bias or noise, and its efficiency and accuracy depend mainly on the number of propagated particles which can easily and significantly increase as a result of this imprecision. In this part, we introduce the interval framework to deal with the problems of the non-white biased measurements and bounded errors. We use the Box Particle Filter (BPF), an estimator based simultaneously on the interval analysis and on the particle approach. We aim to estimate some immeasurable state from the vehicle dynamics using the bounded error Box Particle algorithm, like the roll angle and the lateral load transfer, which are two dynamic states of the vehicle. BPF gives a guaranteed estimation of the state vector. The box encountering the estimation is guaranteed to encounter thereal value of the estimated variable as well.In the second part of this thesis, we aim to compute a vehicle stable state domain.An algorithm, based on the set inversion principle and the constraints satisfaction,is used. Considering the longitudinal velocity and the side slip angle at the vehicle centre of gravity, we characterize the set of these two state variables that corresponds to a stable behaviour : neither roll-over nor sliding. Concerning the roll-over risk,we use the lateral transfer ratio LTR as a risk indicator. Concerning the sliding risk, we use the wheels side slip angles. All these variables are related geometrically to the longitudinal velocity and the side slip angle at the centre of gravity. Using these constraints, the set inversion principle is applied in order to define the set ofthe state variables where the two mentioned risks are avoided. The algorithm of Sivia is implemented. Knowing the vehicle trajectory, a maximal allowed velocityon every part of this trajectory is deduced
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Avcu, Soner. "Radar Pulse Repetition Interval Tracking With Kalman Filter." Thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607691/index.pdf.
Testo completoAbstract (sommario):
In this thesis, the radar pulse repetition interval (PRI) tracking with Kalman Filter problem is investigated. The most common types of PRIs are constant PRI, step (jittered) PRI, staggered PRI, sinusoidally modulated PRI. This thesis considers the step (this type of PRI agility is called as constant PRI when the jitter on PRI values is eliminated) and staggered PRI cases. Different algorithms have been developed for tracking step and staggered PRIs cases. Some useful simplifications are obtained in the algorithm developed for step PRI sequence. Two different algorithms robust to the effects of missing pulses obtained for staggered PRI sequence are compared according to estimation performances. Both algorithms have two parts: detection of the period part and a Kalman filter model. The advantages and disadvantages of these algorithms are presented. Simulations are implemented in MATLAB.
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Gomes, Adriano de Araújo. "Algoritmo das projeções sucessivas para seleção de variáveis em calibração de segunda ordem." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/8196.
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Previous issue date: 2015-06-29<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>In this work it was developed a new strategy for intervals selection using the successive projections algorithm (SPA) coupled to N-PLS and U-PLS models, both with residual bilinearização (RBL) as a post-calibration step. The new algorithm coupled to N-PLS/RBL models was evaluated in two cases of studies. The first was simulated data for quantitation of two analytes (A and B) in the presence of a single interfering. On the second study was conducted a quantitation of ofloxacin in water in the presence of interferents (ciprofloxacin and danofloxacin) by means of liquid chromatography with diode array detection (LC-DAD) data modeling. The results were compared to the N-PLS/RBL model and the variables selection with the genetic algorithm (GA-N-PLS/RBL). In the first case of study (simulated data) were observed RMSEP values (x 10-3 in arbitrary units) for the analytes A and B in the order of 6.7 to 47.6; 10.6 to 11.4; and 6.0 to 14.0 for the N-PLS/RBL, Ga-N-PLS/RBL and the proposed method, respectively. On the second case of study (HPLC-DAD data) RMSEP value (mg/L) of 0.72 (N-PLS/RBL); 0.70 (GA-N-PLS/RBL) and 0.64 (iSPA N-PLS/RBL) were obtained. When combined with the U-PLS/RBL, the new algorithm was evaluated in the EEM modeling in the presence of inner filter effect. Simulated data and quantitation of phenylephrine in the presence of acetaminophen in water sample and interferences (ibuprofen and acetylsalicylic acid) were used as a case of studies. The results were compared to the U-PLS/RBL and e twell established method PARAFAC. For simulated data was observed the following RMSEP values (in arbitrary units) 1.584; 0.077 and 0.066 for PARAFAC; U-PLS/RBL and the proposed method, respectively. In the quantitation of phenylephrine the found RMSEP (in μg/L) were of 0.164 (PARAFAC); 0.089 (U-PLS/RBL) and 0.069 (ISPA-U-PLS/RBL). In all cases it was shown that variables selection is a useful tool capable of improving accuracy when compared with the respective global models (model without variables selection) leading to more parsimonious models. It was observed in all cases, that the sensitivity loss promoted by variables selection is compensated by using more selective channels, justifying the obtained RMSEP smaller values. Finally, it was also observed that the models based on variables selection such as the proposed method were free from significant bias at 95% confidence.<br>Neste trabalho foi desenvolvida uma nova estratégia para seleção de intervalos empregando o algoritmo das projeções sucessivas (SPA) acoplado a modelos N-PLS e U-PLS, ambos com etapa pós-calibração de bilinearização residual (RBL). O novo algoritmo acoplado a modelos N-PLS/RBL, foi avaliado em dois estudos de casos. O primeiro envolvendo dados simulados para quantificação de dois analitos (A e B) na presença de um único interferente. No segundo foi conduzida a quantificação de ofloxacina em água na presença de interferentes (ciprofloxacina e danofloxacina) por meio da modelagem de dados cromatografia liquida com detecção por arranjo de diodos (LC-DAD). Os resultados obtidos foram comparados ao modelo N-PLS/RBL e a seleção de variáveis com o algoritmo genético (GA-N-PLS/RBL). No primeiro estudo de caso (dados simulados) foram observados valores de RMSEP (x 10-3 em unidades arbitrárias) para os analitos A e B da ordem de 6,7 e 47,6; 10,6 e 11,4; 6,0 e 14,0 para o N-PLS/RBL, GA-N-PLS/RBL e o método proposto, respectivamente. No segundo estudo de caso (dados HPLC-DAD) valores de RMSEP (em mg/L) de 0,72 (N-PLS/RBL); 0,70 (GA-N-PLS/RBL) e 0,64 (iSPA-N-PLS/RBL) foram obtidos. Quando combinado com o U-PLS/RBL o novo algoritmo foi avaliado na modelagem de EEM em presença efeito de filtro interno. Dados simulados e a quantificação de fenilefrina na presença de paracetamol em amostras de água e interferentes (Ibuprofeno e ácido acetil salicílico) foram usados como estudos de caso. Os resultados obtidos foram comparados ao modelo U-PLS/RBL e ao bem estabelecido método PARAFAC. Para dados simulados foram observado os seguintes valores de RMSEP (em unidades arbitrarias) 1,584; 0,077 e 0,066 para o PARAFAC; U-PLS/RBL e método proposto, respectivamente. Na quantificação de fenilefrina os RMSEP (em μg/L) encontrados foram de 0,164 (PARAFAC); 0,089 (U-PLS/RBL) e 0,069 (iSPA-U-PLS/RBL). Em todos os casos foi demostrado que seleção de variáveis é uma ferramenta útil capaz de melhorar a acurácia quando comparados aos respectivos modelos globais (modelo sem seleção de variáveis) e tornar os modelos mais parcimoniosos. Foi observado ainda para todos os casos, que a perda de sensibilidade promovida pela seleção de variáveis é compensada pelo uso de canais mais seletivos, justificando os menores valores de RMSEP obtidos. E por fim, foi também observado que os modelos baseados em seleção de variáveis como o método proposto foram isentos de bias significativos a 95% de confiança.
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Merlinge, Nicolas. "State estimation and trajectory planning using box particle kernels." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS425/document.
Testo completoAbstract (sommario):
L'autonomie d'un engin aérospatial requière de disposer d'une boucle de navigation-guidage-pilotage efficace et sûre. Cette boucle intègre des filtres estimateurs et des lois de commande qui doivent dans certains cas s'accommoder de non-linéarités sévères et être capables d'exploiter des mesures ambiguës. De nombreuses approches ont été développées à cet effet et parmi celles-ci, les approches particulaires présentent l'avantage de pouvoir traiter de façon unifiée des problèmes dans lesquels les incertitudes d’évolution du système et d’observation peuvent être soumises à des lois statistiques quelconques. Cependant, ces approches ne sont pas exemptes de défauts dont le plus important est celui du coût de calcul élevé. D'autre part, dans certains cas, ces méthodes ne permettent pas non plus de converger vers une solution acceptable. Des adaptations récentes de ces approches, combinant les avantages du particulaire tel que la possibilité d'extraire la recherche d'une solution d'un domaine local de description et la robustesse des approches ensemblistes, ont été à l'origine du travail présenté dans cette thèse.Cette thèse présente le développement d’un algorithme d’estimation d’état, nommé le Box Regularised Particle Filter (BRPF), ainsi qu’un algorithme de commande, le Box Particle Control (BPC). Ces algorithmes se basent tous deux sur l’utilisation de mixtures de noyaux bornés par des boites (i.e., des vecteurs d’intervalles) pour décrire l’état du système sous la forme d’une densité de probabilité multimodale. Cette modélisation permet un meilleur recouvrement de l'espace d'état et apporte une meilleure cohérence entre la prédite et la vraisemblance. L’hypothèse est faite que les incertitudes incriminées sont bornées. L'exemple d'application choisi est la navigation par corrélation de terrain qui constitue une application exigeante en termes d'estimation d'état.Pour traiter des problèmes d’estimation ambiguë, c’est-à-dire lorsqu’une valeur de mesure peut correspondre à plusieurs valeurs possibles de l’état, le Box Regularised Particle Filter (BRPF) est introduit. Le BRPF est une évolution de l’algorithme de Box Particle Filter (BPF) et est doté d’une étape de ré-échantillonnage garantie et d’une stratégie de lissage par noyau (Kernel Regularisation). Le BRPF assure théoriquement une meilleure estimation que le BPF en termes de Mean Integrated Square Error (MISE). L’algorithme permet une réduction significative du coût de calcul par rapport aux approches précédentes (BPF, PF). Le BRPF est également étudié dans le cadre d’une intégration dans des architectures fédérées et distribuées, ce qui démontre son efficacité dans des cas multi-capteurs et multi-agents.Un autre aspect de la boucle de navigation–guidage-pilotage est le guidage qui nécessite de planifier la future trajectoire du système. Pour tenir compte de l'incertitude sur l'état et des contraintes potentielles de façon versatile, une approche nommé Box Particle Control (BPC) est introduite. Comme pour le BRPF, le BPC se base sur des mixtures de noyaux bornés par des boites et consiste en la propagation de la densité d’état sur une trajectoire jusqu’à un certain horizon de prédiction. Ceci permet d’estimer la probabilité de satisfaire les contraintes d’état au cours de la trajectoire et de déterminer la séquence de futures commandes qui maintient cette probabilité au-delà d’un certain seuil, tout en minimisant un coût. Le BPC permet de réduire significativement la charge de calcul<br>State estimation and trajectory planning are two crucial functions for autonomous systems, and in particular for aerospace vehicles.Particle filters and sample-based trajectory planning have been widely considered to tackle non-linearities and non-Gaussian uncertainties.However, these approaches may produce erratic results due to the sampled approximation of the state density.In addition, they have a high computational cost which limits their practical interest.This thesis investigates the use of box kernel mixtures to describe multimodal probability density functions.A box kernel mixture is a weighted sum of basic functions (e.g., uniform kernels) that integrate to unity and whose supports are bounded by boxes, i.e., vectors of intervals.This modelling yields a more extensive description of the state density while requiring a lower computational load.New algorithms are developed, based on a derivation of the Box Particle Filter (BPF) for state estimation, and of a particle based chance constrained optimisation (Particle Control) for trajectory planning under uncertainty.In order to tackle ambiguous state estimation problems, a Box Regularised Particle Filter (BRPF) is introduced.The BRPF consists of an improved BPF with a guaranteed resampling step and a smoothing strategy based on kernel regularisation.The proposed strategy is theoretically proved to outperform the original BPF in terms of Mean Integrated Square Error (MISE), and empirically shown to reduce the Root Mean Square Error (RMSE) of estimation.BRPF reduces the computation load in a significant way and is robust to measurement ambiguity.BRPF is also integrated to federated and distributed architectures to demonstrate its efficiency in multi-sensors and multi-agents systems.In order to tackle constrained trajectory planning under non-Gaussian uncertainty, a Box Particle Control (BPC) is introduced.BPC relies on an interval bounded kernel mixture state density description, and consists of propagating the state density along a state trajectory at a given horizon.It yields a more accurate description of the state uncertainty than previous particle based algorithms.A chance constrained optimisation is performed, which consists of finding the sequence of future control inputs that minimises a cost function while ensuring that the probability of constraint violation (failure probability) remains below a given threshold.For similar performance, BPC yields a significant computation load reduction with respect to previous approaches
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Janapala, Arun. "RR INTERVAL ESTIMATION FROM AN ECG USING A LINEAR DISCRETE KALMAN FILTER." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3426.
Testo completoAbstract (sommario):
An electrocardiogram (ECG) is used to monitor the activity of the heart. The human heart beats seventy times on an average per minute. The rate at which a human heart beats can exhibit a periodic variation. This is known as heart rate variability (HRV). Heart rate variability is an important measurement that can predict the survival after a heart attack. Studies have shown that reduced HRV predicts sudden death in patients with Myocardial Infarction (MI). The time interval between each beat is called an RR interval, where the heart rate is given by the reciprocal of the RR interval expressed in beats per minute. For a deeper insight into the dynamics underlying the beat to beat RR variations and for understanding the overall variance in HRV, an accurate method of estimating the RR interval must be obtained. Before an HRV computation can be obtained the quality of the RR interval data obtained must be good and reliable. Most QRS detection algorithms can easily miss a QRS pulse producing unreliable RR interval values. Therefore it is necessary to estimate the RR interval in the presence of missing QRS beats. The approach in this thesis is to apply KALMAN estimation algorithm to the RR interval data calculated from the ECG. The goal is to improve the RR interval values obtained from missed beats of ECG data.<br>M.S.E.E.<br>Department of Electrical and Computer Engineering<br>Engineering and Computer Science<br>Electrical Engineering
Libri sul tema "Filtre intervalle"
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Nicklas, Richard B. An application of a Kalman Filter Fixed Interval Smoothing Algorithm to underwater target tracking. Naval Postgraduate School, 1989.
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Galinis, William J. Fixed interval smoothing algorithm for an extended Kalman filter for over-the-horizon ship tracking. Naval Postgraduate School, 1989.
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Weinert, Howard L. Fixed interval smoothing for state space models. Kluwer Academic Publishers, 2001.
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Software, Coda Music. Finale: The art of music notation. 3rd ed. Coda Music Software, 1992.
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Automatic Transmission Service Guide: Fluid Capacity and Recommended Filter Change Intervals. Hearst Business Pub., 2005.
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Inter-Rater Reliability Using SAS: A Practical Guide for Nominal, Ordinal, and Interval Data. Advanced Analytics, LLC, 2010.
Cerca il testo completoCapitoli di libri sul tema "Filtre intervalle"
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Catlin, Donald E. "Fixed Interval Smoothing." In Estimation, Control, and the Discrete Kalman Filter. Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4612-4528-5_9.
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Quislant, Ricardo, Eladio Gutierrez, Oscar Plata, and Emilio L. Zapata. "Interval Filter: A Locality-Aware Alternative to Bloom Filters for Hardware Membership Queries by Interval Classification." In Intelligent Data Engineering and Automated Learning – IDEAL 2010. Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-15381-5_20.
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Sharma, Teena, and Nishchal K. Verma. "Adaptive Interval Type-2 Fuzzy Filter." In Artificial Intelligent Algorithms for Image Dehazing and Non-Uniform Illumination Enhancement. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-2011-8_6.
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Wang, Ziyun, Yan Wang, and Zhicheng Ji. "Fault diagnosis based on interval." In Filter Design for System Modeling, State Estimation and Fault Diagnosis. CRC Press, 2022. http://dx.doi.org/10.1201/b23146-5.
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Forsythe, W., and R. M. Goodall. "Error Mechanisms, Filter Structure, and the Sampling Interval." In Digital Control. Macmillan Education UK, 1991. http://dx.doi.org/10.1007/978-1-349-21550-8_4.
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Guru, D. S., and N. Vinay Kumar. "Clustering of Interval Valued Data Through Interval Valued Feature Selection: Filter Based Approaches." In Mining Intelligence and Knowledge Exploration. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-66187-8_26.
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Wang, Ziyun, Yan Wang, and Zhicheng Ji. "Design of Interval Set-Membership Based Fault Detection Filter." In Advances in Fault Detection and Diagnosis Using Filtering Analysis. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-5959-1_5.
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Li, Hongyi, Ligang Wu, Hak-Keung Lam, and Yabin Gao. "Filter Design of Interval Type-2 Fuzzy-Model-Based Systems." In Analysis and Synthesis for Interval Type-2 Fuzzy-Model-Based Systems. Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-0593-0_7.
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Piazena, H., W. Müller, and Peter Vaupel. "Physical and Photobiological Basics of wIRA-Hyperthermia." In Water-filtered Infrared A (wIRA) Irradiation. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92880-3_3.
Testo completoAbstract (sommario):
AbstractInformation regarding physical and photobiological basics of wIRA-HT has been derived under in vivo conditions in piglets and human tissues. Since wIRA fits into the optical window of tissues, direct conversion of absorbed radiation into heat (T >39 °C) has been proven up to tissue depths of 26 mm. Tissue heating cannot sufficiently be characterized by the specification of the radiant exposure (dose) due to its dependence on the thermal impact of irradiance and exposure time and on heat dissipation and metabolic heat production. If irradiations of identical doses are used, resulting tissue hyperthermia levels are the higher, the shorter the exposure time and the higher the irradiance. To comply with the ESHO criteria, incident wIRA irradiances should exceed ≈ 110 mWcm−2 (IR-A). At higher irradiances, steady-state temperatures (SST) ≥ 39 °C have been observed to tissue depths >20 mm in piglets and up to 26 mm in humans. SST values ≥40 °C have been measured up to tissue depths >20 mm (piglets) and up to 16 mm (humans), and SSTs ≥41 °C up to 16 mm (piglets) and up to 8 mm (humans). Post-heating temperature decay times limit optimal intervals between hyperthermia (HT) and subsequent radiotherapy (RT) sessions to periods ≤5 min.
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Zhao, Shen, Yunwei Zhang, XiWei Guo, and Deliang Liu. "Research on the Linear Interpolation of Equal-Interval Fractional Delay Filter." In Lecture Notes in Electrical Engineering. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-13-9409-6_60.
Testo completoAtti di convegni sul tema "Filtre intervalle"
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Liang, You, Aerambamoorthy Thavaneswaran, Juan Liyau, Areebah Muhammad, Thimani Ranathungage, and Ruppa Thulasiram. "A Cryptocurrency Multiple Trading Strategy with Kalman Filter Innovation Volatility Interval Forecasts." In 2024 IEEE 48th Annual Computers, Software, and Applications Conference (COMPSAC). IEEE, 2024. http://dx.doi.org/10.1109/compsac61105.2024.00037.
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Hu, Jie, Yan Wang, Aiguo Cheng, and Zhihua Zhong. "A Kalman Filtering Mechanism Based on Generalized Interval Probability and its Application in Process Variation Estimation." In ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/detc2014-34543.
Testo completoAbstract (sommario):
The Kalman filter has been widely applied for state identification in controllable systems. As a special case of hidden Markov model, it is based on the assumption of linear dependency relationships and Gaussian noises. The classical Kalman filter does not differentiate systematic error from random error associated with observations. In this paper, we propose an extended Kalman filtering mechanism based on generalized interval probability, where systematic error is represented by intervals, state and observable variables are random intervals, and interval-valued Gaussian distributions model the noises. The prediction and update procedures in the new mechanism are derived. A case study of auto-body side frame assembly is used to illustrate the developed mechanism.
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Madsen, Stian, Jørn Watvedt, and Lars E. Bakken. "Gas Turbine Fouling Offshore: Air Intake Filtration Optimization." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75613.
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Optimized operation of gas turbines is discussed for a fleet of eleven LM2500PE engines at a Statoil North Sea offshore field in Norway. Three engines are generator drivers while eight engines are compressor drivers. Several of the compressor drive engines run at peak load (T5.4 control), hence production rate is limited by the available power from these engines. The majority of the engines discussed run continuously without redundancy, hence gas turbine uptime is critical for the field’s production and economy. The performance and operational experience with upgraded inlet air filter systems, as well as successful operation at longer maintenance intervals and higher average engine performance are described. For North Sea operation, a key property of the filter system is the ability to handle high humidity and high salt-content, typical of the harsh environment in these waters. The upgraded filter system analyzed in this paper is a 2-stage system (vane separator stage upstream of the high-efficiency filter stage), which is a simplified design versus the old traditional 3-stage systems (louvre upstream and vane separator downstream of the filter stage). These 2-stage systems rely on an efficient upstream vane separator to remove the vast majority of water from the airflow before it reaches the high-efficiency filters. The high-efficiency filters are specially designed to withstand moisture. The effectiveness and contribution of each component in the filtration system are described. Extensive testing of both new and used filter elements, of different filter grade and operated at different intervals, has been performed in a filter test rig facility onshore. Extensive testing of used filters has also been performed at the filter OEM, where filter efficiency is measured as well as destructive testing and analysis of the filter layers. The effect of an optimized air intake filter system for the subject engines, is longer operating intervals, higher power availability and lower engine deterioration. The operating intervals are now extended to six months (4,000 hours), from initially two months (1,500 hours, early 1990s) then four months (3,000 hours, mid 2000s). The HPC efficiency deterioration is reduced by some 3% related to intake filter system, of a total of over 6% in efficiency deterioration over each 6-month operating period.
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Gomes, Daiana Caroline, and Ginalber Serra. "Algoritmo de Filtro de Kalman Baseado em Modelo Fuzzy Tipo-2 Evolutivo para Rastreamento." In Congresso Brasileiro de Inteligência Computacional. SBIC, 2023. http://dx.doi.org/10.21528/cbic2023-010.
Testo completoAbstract (sommario):
Neste artigo, um filtro de Kalman fuzzy tipo-2 evolutivo e proposto para o processamento intervalar de dados experimentais a partir de componentes espectrais não-observáveis. A metodologia adotada considera as seguintes etapas: um modelo inicial do filtro de Kalman fuzzy tipo-2 evolutivo e identificado de forma off-line a partir de uma janela inicial de dados experimentais; a atualização da proposição do antecedente do filtro de Kalman fuzzy tipo-2 evolutivo e realizada usando uma formulação fuzzy tipo-2 intervalar do algoritmo de agrupamento evolving Takagi-Sugeno (eTS) e a atualização da proposição consequente e realizada usando uma formulação fuzzy tipo-2 do algoritmo Observer/Kalman Filter Identification (OKID), levando em consideração as componentes espectrais não-observáveis extraídas dos dados experimentais por meio de um algoritmo de Análise Espectral Singular Recursiva Multivariável. Resultados experimentais e análise comparativa referentes ao rastreamento intervalar de um helicóptero 2DoF ilustram a eficiência da metodologia proposta.
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Dos Santos Gomes, Daiana Caroline, and Ginalber Luiz De Oliveira Serra. "Filtragem Computacional de Kalman Fuzzy Tipo-2 para Rastreamento e Previsão da Dinâmica de Propagação da COVID-19: Estudo de Caso Aplicado ao Brasil." In Congresso Brasileiro de Automática - 2020. sbabra, 2020. http://dx.doi.org/10.48011/asba.v2i1.986.
Testo completoAbstract (sommario):
Neste artigo é proposto um modelo computacional para a análise da dinâmica de propagação da COVID-19 utilizando sistemas fuzzy tipo-2. A metodologia adotada consiste na estimação paramétrica recursiva de um filtro de Kalman fuzzy tipo-2 intervalar para rastreamento e previsão da dinâmica presente nos dados experimentais, usando uma versão fuzzy tipo-2 intervalar do algoritmo Observer/Kalman Filter Identification (OKID). O particionamento dos dados experimentais é obtido pelo algoritmo de agrupamento Gustafson-Kessel tipo-2 intervalar. Os ganhos de Kalman intervalares na proposição do consequente do filtro de Kalman tipo-2 intervalar são atualizados de acordo com as componentes não observáveis obtidas por meio da decomposição espectral recursiva dos dados experimentais. Resultados experimentais ilustram a eficiência e aplicabilidade da metodologia proposta para rastreamento e previsão adaptativa em tempo real do comportamento de propagação dinâmica do novo Coronavírus 2019 (COVID-19) no Brasil quando comparada a abordagens relevantes da literatura.
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Madsen, Stian, and Lars E. Bakken. "Gas Turbine Operation Offshore: Increased Operating Interval and Higher Engine Performance Through Optimized Intake Air Filter System." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56066.
Testo completoAbstract (sommario):
Optimized operation of gas turbines is discussed for six LM2500PE engines at a Statoil North Sea offshore field. Three engines are generator drivers whilst three engines are compressor drivers. Two of the compressor drive engines are running at peak load (T5.4 control), hence the production rate is limited by the available power from these engines. All of the six engines discussed run continuously without redundancy, gas turbine uptime is therefore critical for the field’s production and economy. The performance and operational experience with upgraded inlet air filter systems and online water wash at high water-to-air ratio, as well as successful operation at longer intervals and higher average engine performance are described. For North Sea operation, a key property of the filter system is the ability to handle high humidity and high salt-content through the harsh environment in these waters. The upgraded filter systems analyzed in this paper is a 2-stage system (vane separator stage upstream of the high-efficiency-filter stage), which is a simplified design versus the old traditional 3-stage systems (louvre upstream and vane separator downstream of the filter stage). These 2-stage systems rely on an efficient upstream vane separator to remove the vast majority of water from the airflow before it reaches the high-efficiency filters. The high-efficiency filters are especially designed to withstand moisture. Deposit analysis from the downstream side of the filters has been performed. Extensive testing of both new and used filter elements, of different filter grade and operated at different intervals, has been performed on a filter test rig facility onshore. All six engines have historically been operated with 4-month intervals between maintenance stops. Online wash is performed daily between the maintenance stops at full load (i.e. normal operating load for the subject engine). As a result of successful development and pilot testing of new filters and optimized filter change intervals, as well as successful online water wash, the engine operating intervals are now extended to 6 months with very low deterioration rate. Understanding the gas turbine performance deterioration is of vital importance. Trending of its deviation from the engine baseline facilitates load-independent monitoring of the gas turbine’s condition. Instrument resolution and repeatability are key factors in order to get reasonable results from the performance analysis. Improvement of the package instrumentation has been implemented on three of the analyzed engines, for better performance monitoring. As a result of these analyses, a set of monitoring parameters is suggested for effective diagnostics of compressor degradation. Avenues for further research and development are proposed in order to further increase the understanding of the deterioration mechanisms and the gas turbine performance and response.
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Marshall, Lauren, Adam Schroeder, and Brian Trease. "Comparing Fish-Inspired Ram Filters for Collection of Harmful Algae." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-88797.
Testo completoAbstract (sommario):
In this work, several different bioinspired filter geometries are proposed, fabricated, and tested in a flow tank. A novel approach is explored that mimics how filter-feeding fish efficiently remove small food particles from water. These filters generally take the form of a cone with water entering the large end of the cone and exiting through mesh-covered slots in the side of the cone, which emulates the rib structure of these filter-feeding fish. The flow in and around the filters is characterized and their ability to collect algae-scale, neutrally-buoyant particles is evaluated. Filter performance is evaluated by using image processing to count the number of particles collected and studying how the particles are deposited on the filter. Results are presented in the form of particle collection efficiencies, which is a ratio of particles collected to the particles that would nominally enter the filter inlet, and images of the fluorescent particles deposited on the filter at different time intervals. The results show little sensitivity to the filters’ inlet geometries, which was the major difference between filters tested. Comparative results are also presented from a 2D CFD model of the filters generated in COMSOL. The different geometries may differentiate themselves more at larger Reynolds numbers, and it is believed that a fluid exit ratio, or ratio of inlet area to exit area, is the most critical filter parameter. Field testing has demonstrated collection of real algae (i) with this bioinspired filter, and (ii) from a robot platform, but using a more conventional plankton net. The larger vision is to develop these filters and mount them on a swarm of autonomous surface vehicles, i.e. a robot boat swarm, which is being developed in parallel.
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Watson, Simon A. G., Victor W. Wong, Darrell Brownawell, and Scott P. Lockledge. "Controlling Lubricant Acidity With an Oil Conditioning Filter." In ASME 2009 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/ices2009-76100.
Testo completoAbstract (sommario):
In modern diesel engines, acidity generally determines the lubricant drain interval. To control acidity, lubricant suppliers incorporate detergent additives to neutralize acids that accumulate in the oil via exhaust blow-by and base-stock oxidation. However, formulations that meet the most recent diesel lubricant classification specifications typically contain lower levels of detergent since this additive contributes to ash that fouls emissions aftertreatment systems. This study explores a novel approach to lubricant acid control as a potential means to reduce additive requirements or increase oil drain interval. The authors investigate the performance of an innovative oil filter that releases no additives into the lubricant, yet enhances the acid control function typically performed by detergent and dispersant additives. The filter chemically conditions the crankcase oil during engine operation by sequestering acidic compounds derived from engine combustion and lubricant degradation. Long duration heavy-duty diesel engine tests show that the filter reduces both the rate of Total Base Number (TBN) decline and the rate of Total Acid Number (TAN) increase by a factor of two. Analysis by Fourier transform infra-red (FTIR) spectroscopy also indicates that lubricant oxidation may be lowered. In addition, these results suggest a reduction in engine wear. These results imply that lower lubricant additive levels in combination with this novel oil filter may be used to reduce ash accumulation in diesel aftertreatment systems, while maintaining adequate engine protection. The results also indicate that the engine operator may use this oil filter with a state-of-the art lubricant to lengthen oil change intervals.
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Lyons, James W., and Alex Morrison. "Utility Perspective of Selecting Air Filter for Simple-Cycle, Heavy-Duty Combustion Turbines." In ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/92-gt-321.
Testo completoAbstract (sommario):
The combustion turbines evaluated for this study range in size (nominal) from 80 MW to 100 MW and operate at a compression ratio between 10 and 14. Under these conditions the compressor ingests about 500,000 to 725,000 cubic feet of air per minute for its rated output. With this volume of air, even low concentrations of contaminants can result in a significant total amount of contaminants entering the unit, which may cause compressor erosion, fouling, and foreign object damage in the compressor section and cooling air passage blockage, locking of turbine blade roots, and hot corrosion or sulfidation in the turbine section. Adequate protection against the above mentioned degradation or damage due to poor air quality may be obtained by using properly designed air filters. An inadequate filter system or having no filter system results in a reduction in power and efficiency over the life of the unit and may significantly decrease the intervals between maintenance and thereby increase the cost of maintenance. Consideration should be given to adding an air inlet filter when or after the combustion turbine without air filter is overhauled to reduce future maintenance costs. This study investigates the need for an inlet air filtration system for the simple-cycle, heavy-duty combustion turbines from a cost/benefit and operation standpoint. Options for inlet air filters include a self-cleaning pulse type filter, a surface loading cartridge filter without pulse feature, and a three-stage depth loading type media type filter. Benefits are determined by estimates of improvements in performance and effects on the combustion turbine’s longevity and maintenance.
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Takemura, Kentaro, Euisun Kim, and Jun Ueda. "Individualized Inter-Stimulus Interval Estimation for Neural Facilitation in Human Motor System: A Particle Filtering Approach." In ASME 2018 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/dscc2018-9155.
Testo completoAbstract (sommario):
Quantitative understanding of the human neuromotor system is essential for the implementation of the future robotic therapeutic exercises. For this purpose, sensorimotor adaptations in voluntary and involuntary movements facilitated by peripheral stimulation and resultant motor-evoked potentials (MEP) must be well characterized. One such facilitation exercise is paired associative stimulation (PAS). However, effective inter-stimulus intervals between cortical and peripheral stimulations are highly variable between individuals due to different physiological characteristics. Past studies measured MEPs in a wide range of time by incrementally varying inter-stimulus intervals to find the optimal interval in a specific subject, which has been a time-consuming process. This paper develops a search algorithm based on particle filtering to estimate individualized inter-stimulus intervals for PAS with mechanical muscle tendon stimulation realized by a pneumatically-operated robotic neuromodulatory system. The particle filter-based method reduces the number of PAS trials 70%–80% in comparison to the conventional incremental method. An accelerometer attached to the robotic system that measures exact timings of tendon stimulation can further reduce the number of trials.
Rapporti di organizzazioni sul tema "Filtre intervalle"
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Bhattarai, Rabin, Yufan Zhang, and Jacob Wood. Evaluation of Various Perimeter Barrier Products. Illinois Center for Transportation, 2021. http://dx.doi.org/10.36501/0197-9191/21-009.
Testo completoAbstract (sommario):
Construction activities entail substantial disturbance of topsoil and vegetative cover. As a result, stormwater runoff and erosion rates are increased significantly. If the soil erosion and subsequently generated sediment are not contained within the site, they would have a negative off-site impact as well as a detrimental influence on the receiving water body. In this study, replicable large-scale tests were used to analyze the ability of products to prevent sediment from exiting the perimeter of a site via sheet flow. The goal of these tests was to compare products to examine how well they retain sediment and how much ponding occurs upstream, as well as other criteria of interest to the Illinois Department of Transportation. The products analyzed were silt fence, woven monofilament geotextile, Filtrexx Siltsoxx, ERTEC ProWattle, triangular silt dike, sediment log, coconut coir log, Siltworm, GeoRidge, straw wattles, and Terra-Tube. Joint tests and vegetated buffer strip tests were also conducted. The duration of each test was 30 minutes, and 116 pounds of clay-loam soil were mixed with water in a 300 gallon tank. The solution was continuously mixed throughout the test. The sediment-water slurry was uniformly discharged over an 8 ft by 20 ft impervious 3:1 slope. The bottom of the slope had a permeable zone (8 ft by 8 ft) constructed from the same soil used in the mixing. The product was installed near the center of this zone. Water samples were collected at 5 minute intervals upstream and downstream of the product. These samples were analyzed for total sediment concentration to determine the effectiveness of each product. The performance of each product was evaluated in terms of sediment removal, ponding, ease of installation, and sustainability.