Academic literature on the topic 'Onde quantique'
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Journal articles on the topic "Onde quantique"
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Bouyer, Philippe. ". Mesurer l’accélération avec des ondes de matière : de la gravimétrie à la navigation." Photoniques, no. 88 (September 2017): 42–44. http://dx.doi.org/10.1051/photon/20178842.
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Refroidis proche du zéro absolu, les atomes se comportent non plus comme des particules, mais comme des ondes de matière dont la propagation peut conduire à des phénomènes d'interférence. Ces interférences peuvent être exploitées pour mesurer l’accélération avec une très haute précision. Les capteurs inertiels quantiques qui en découlent sont aujourd’hui des dispositifs prometteurs de nombreuses applications comme le guidage et la navigation, ou la gravimétrie ultra-précise.
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Serafin, Tomasz, Bartosz Uniejewski, and Rafał Weron. "Averaging Predictive Distributions Across Calibration Windows for Day-Ahead Electricity Price Forecasting." Energies 12, no. 13 (July 3, 2019): 2561. http://dx.doi.org/10.3390/en12132561.
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The recent developments in combining point forecasts of day-ahead electricity prices across calibration windows have provided an extremely simple, yet a very efficient tool for improving predictive accuracy. Here, we consider two novel extensions of this concept to probabilistic forecasting: one based on Quantile Regression Averaging (QRA) applied to a set of point forecasts obtained for different calibration windows, the other on a technique dubbed Quantile Regression Machine (QRM), which first averages these point predictions, then applies quantile regression to the combined forecast. Once computed, we combine the probabilistic forecasts across calibration windows by averaging probabilities of the corresponding predictive distributions. Our results show that QRM is not only computationally more efficient, but also yields significantly more accurate distributional predictions, as measured by the aggregate pinball score and the test of conditional predictive ability. Moreover, combining probabilistic forecasts brings further significant accuracy gains.
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Zhang, Jianwei, William W. Oliver, and Robert F. Powers. "Reevaluating the self-thinning boundary line for ponderosa pine (Pinus ponderosa) forests." Canadian Journal of Forest Research 43, no. 10 (October 2013): 963–71. http://dx.doi.org/10.1139/cjfr-2013-0133.
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The self-thinning rule has been used extensively to predict population dynamics under intraspecific and interspecific competition. In forestry, it is an important silvicultural concept for maintaining stand health in the face of climate change and biotic stress, but uncertainty exists because traditional self-thinning limits were set subjectively without regard to site quality. We addressed this by analyzing ponderosa pine (Pinus ponderosa Lawson & C. Lawson) data from 109 research plots measured repeatedly and 59 inventory plots measured once across California. Self-thinning boundaries were fitted to the data with quantile regression and stochastic frontier function (SFF) techniques with and without site index (SI) as a covariate. The models from both methods fitted the data well with either research plots or all plots. Slopes for size-density trajectories were –0.45 with the 0.99 quantile and –0.47 for SFF. Maximum stand density indices (SDI) were 1250 trees per hectare (TPH) with the 0.99 quantile and 1050–1060 TPH with SFF. Mortality occurred when site occupancy from SFF reached 0.75, suggesting a zone of imminent mortality. Curvilinear trends in maximum SDI across SI for both methods indicate that self-thinning varies with site quality. Any management regimes that increase site quality and productivity will increase the self-thinning boundary.
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Grosjean, Ph, Ch Spirlet, and M. Jangoux. "A functional growth model with intraspecific competition applied to a sea urchin, Paracentrotus lividus." Canadian Journal of Fisheries and Aquatic Sciences 60, no. 3 (March 1, 2003): 237–46. http://dx.doi.org/10.1139/f03-017.
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A new growth model is fitted on data from reared sea urchins, Paracentrotus lividus. Quantile regressions are used instead of least-square regressions, because they are insensitive to the dimension of the measurement and accommodate more than just symmetrical distributions. Quantile regressions allow comparison of fittings on various parts of the size distributions, including large competitors versus small, inhibited animals, in the presence of a size-based intraspecific competition. The model has functionally interpretable parameters and allows quantifying of the intensity of growth inhibition. An extension of this model, called "envelope model", fits the whole data set at once, including size distributions. Its parameters are constrained using information about underlying biological processes involved, namely asymptotic growth with inhibition in early ages as the result of intraspecific competition, the intensity of which depends on the relative size of the individual in the cohort. The new model appears most adequate to describe growth of P. lividus and probably many other sea urchins species as well as other animals or plants.
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Malmstadt, Jill C., James B. Elsner, and Thomas H. Jagger. "Risk of Strong Hurricane Winds to Florida Cities." Journal of Applied Meteorology and Climatology 49, no. 10 (October 1, 2010): 2121–32. http://dx.doi.org/10.1175/2010jamc2420.1.
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Abstract A statistical procedure for estimating the risk of strong winds from hurricanes is demonstrated and applied to several major cities in Florida. The procedure, called the hurricane risk calculator, provides an estimate of wind risk over different length periods and can be applied to any location experiencing this hazard. Results show that the city of Miami can expect to see hurricane winds blowing at 50 m s−1 [45.5–54.5 m s−1 is the 90% confidence interval (CI)] or stronger, on average, once every 12 yr. In comparison, the city of Pensacola can expect to see hurricane winds of 50 m s−1 (46.9–53.1 m s−1, 90% CI) or stronger once every 24 yr. A quantile regression is applied to hurricane wind speeds in the vicinity of Florida. Results show that the strongest hurricanes are getting stronger as a consequence of higher offshore intensification rates.
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Tylkowski, Jacek, and Marcin Hojan. "Threshold Values of Extreme Hydrometeorological Events on the Polish Baltic Coast." Water 10, no. 10 (September 27, 2018): 1337. http://dx.doi.org/10.3390/w10101337.
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The main aim of this study is to determine the threshold values for extreme sea and weather events on the Polish Baltic coast. The study is based on daily hydrometeorological data on the sea level; air temperature and atmospheric precipitation collected between 1965–2014 from six coastal sites (Świnoujście; Kołobrzeg, Ustka, Łeba, Hel, and Gdynia/Gdańsk). Threshold values for the occurrence of extreme events (with a probability of 10% and 95%, and a return rate of once every 10 years) and exceptionally extreme events (with a probability of 1% and 99%, and a return rate of once every 100 years) were determined using probability distribution and quantile analysis. Hydrometeorological absolute extremes were also determined. The methodology used to determine these extreme events and the time-space analysis of hydrometeorological extremes reveal significant geohazards for the functioning of the Baltic coastal zone, including the erosion of coastal dunes and cliffs and the destruction of technical infrastructure.
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Pierce, David W., Daniel R. Cayan, Edwin P. Maurer, John T. Abatzoglou, and Katherine C. Hegewisch. "Improved Bias Correction Techniques for Hydrological Simulations of Climate Change*." Journal of Hydrometeorology 16, no. 6 (November 13, 2015): 2421–42. http://dx.doi.org/10.1175/jhm-d-14-0236.1.
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Abstract Global climate model (GCM) output typically needs to be bias corrected before it can be used for climate change impact studies. Three existing bias correction methods, and a new one developed here, are applied to daily maximum temperature and precipitation from 21 GCMs to investigate how different methods alter the climate change signal of the GCM. The quantile mapping (QM) and cumulative distribution function transform (CDF-t) bias correction methods can significantly alter the GCM’s mean climate change signal, with differences of up to 2°C and 30% points for monthly mean temperature and precipitation, respectively. Equidistant quantile matching (EDCDFm) bias correction preserves GCM changes in mean daily maximum temperature but not precipitation. An extension to EDCDFm termed PresRat is introduced, which generally preserves the GCM changes in mean precipitation. Another problem is that GCMs can have difficulty simulating variance as a function of frequency. To address this, a frequency-dependent bias correction method is introduced that is twice as effective as standard bias correction in reducing errors in the models’ simulation of variance as a function of frequency, and it does so without making any locations worse, unlike standard bias correction. Last, a preconditioning technique is introduced that improves the simulation of the annual cycle while still allowing the bias correction to take account of an entire season’s values at once.
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Tiňo, Peter, and Jozef Šajda. "Learning and Extracting Initial Mealy Automata with a Modular Neural Network Model." Neural Computation 7, no. 4 (July 1995): 822–44. http://dx.doi.org/10.1162/neco.1995.7.4.822.
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A hybrid recurrent neural network is shown to learn small initial mealy machines (that can be thought of as translation machines translating input strings to corresponding output strings, as opposed to recognition automata that classify strings as either grammatical or nongrammatical) from positive training samples. A well-trained neural net is then presented once again with the training set and a Kohonen self-organizing map with the “star” topology of neurons is used to quantize recurrent network state space into distinct regions representing corresponding states of a mealy machine being learned. This enables us to extract the learned mealy machine from the trained recurrent network. One neural network (Kohonen self-organizing map) is used to extract meaningful information from another network (recurrent neural network).
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Muhammad, Ameer, Tricia Stadnyk, Fisaha Unduche, and Paulin Coulibaly. "Multi-Model Approaches for Improving Seasonal Ensemble Streamflow Prediction Scheme with Various Statistical Post-Processing Techniques in the Canadian Prairie Region." Water 10, no. 11 (November 8, 2018): 1604. http://dx.doi.org/10.3390/w10111604.
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Hydrologic models are an approximation of reality, and thus, are not able to perfectly simulate observed streamflow because of various sources of uncertainty. On the other hand, skillful operational hydrologic forecasts are vital in water resources engineering and management for preparedness against flooding and extreme events. Multi-model techniques can be used to help represent and quantify various uncertainties in forecasting. In this paper, we assess the performance of a Multi-model Seasonal Ensemble Streamflow Prediction (MSESP) scheme coupled with statistical post-processing techniques to issue operational uncertainty for the Manitoba Hydrologic Forecasting Centre (HFC). The Ensemble Streamflow Predictions (ESPs) from WATFLOOD and SWAT hydrologic models were used along with four statistical post-processing techniques: Linear Regression (LR), Quantile Mapping (QM), Quantile Model Averaging (QMA), and Bayesian Model Averaging (BMA)]. The quality of MSESP was investigated from April to July with a lead time of three months for the Upper Assiniboine River Basin (UARB) at Kamsack, Canada. While multi-model ESPs coupled with post-processing techniques improve predictability (in general), results suggest that additional avenues for improving the skill and value of seasonal streamflow prediction. Next steps towards an operational ESP system include adding more operationally used models, improving models calibration methods to reduce model bias, increasing ESP sample size, and testing ESP schemes at multiple lead times, which, once developed, will not only help HFCs in Canada but would also help Centers South of the Border.
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Louzada, Francisco, Cintia Y. Yamachi, Vitor A. A. Marchi, and Maria A. P. Franco. "The long-term exponentiated complementary exponential geometric distribution under a latent complementary causes framework." TEMA (São Carlos) 15, no. 1 (July 12, 2014): 019. http://dx.doi.org/10.5540/tema.2014.015.01.0019.
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<p><span>A new lifetime distribution which accommodates decreasing and unimodal hazard function is proposed in this paper. It is derived from the exponentiated complementary exponential geometric distribution and has it genesis on the compounding the exponential and geometric distributions. It can be used on a latent complementary causes scenario, where onle thethe minimum lifetime among all causes is observed. We derive the density, quantile, survival and failure rate functions for the proposed distribution, as well as some proprieties such as the characteristic function, mean, variance and r-th order statistics. The estimation is based on maximum likelihood approach. A simulation study performed in order to assess the performance of the maximum likelihood estimates of the parameters of the proposed distribution. The methodology is illustrated in three real datasets. </span></p>
Dissertations / Theses on the topic "Onde quantique"
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Ringot, Jean. "Chaos quantique avec des atomes froids dans une onde stationnaire." Lille 1, 2000. http://www.theses.fr/2000LIL10130.
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En soumettant un nuage d'atomes de césium refroidis par laser à une onde stationnaire pulsée périodiquement, nous avons réalisé expérimentalement un système quantique dont la dynamique dans la limite classique (h 0) est chaotique. Ce système est un modèle de choix pour des études de chaos quantique unidimensionnel. Grâce à des mesures de distributions de vitesses atomiques par spectroscopie Raman stimulé, nous avons pu mettre en évidence le phénomène de localisation dynamique qui provoque un gel de la diffusion des impulsions atomiques par interférences quantiques. En superposant une seconde série de forçage périodiques, nous avons formellement ajouté une dimension au système. Nos observations ont montré la sensibilité du système au rapport des deux périodes de forçage. La localisation dynamique apparaît ou disparaît selon que le rapport est un irrationnel ou non.
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Le, Bars Julien. "Etude du bruit quantique dans la détection interférométrique des ondes gravitationnelles." Paris 6, 2010. http://www.theses.fr/2010PA066200.
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La construction de la première génération d’interféromètres à ondes gravitationnelles est maintenant achevée et d’importants efforts internationaux portent sur leur perfectionnement pour les convertir en de véritables observatoires. Le bruit quantique sera une des principales limitations de ces instruments. Il a pour origine les fluctuations quantiques de phase et d’intensité de la lumière laser utilisée. Ma thèse consiste en la réalisation d’un modèle numérique de ce bruit. Le code repose sur des modules élémentaires quantiques permettant une application facile aux diverses configurations d’interféromètre. Chaque module individuel décrit la transformation des fluctuations quantiques par l’élément optique correspondant. Il existe sous deux représentations : une représentation de diffusion donnant accès au relation d’entrée sortie et donc à la sensibilité et une représentation de transfert utilisé pour l’assemblage des éléments individuels. Le code intègre des opérations canoniques comme le passage réciproque d’une représentation à l’autre et l’algèbre d’assemblage des éléments optiques. Le code intègre aussi l’estimation des bruits de perte d’origine également quantique et les bruits classiques. Il permet ainsi de déterminer la sensibilité des interféromètres de configuration semblable à VIRGO ou LIGO de tester diverses techniques de réduction du bruit quantique comme l’injection d’états comprimés du champ ou la détection homodyne. Des effets de couplage entre les deux cavités constituant les bras de l’interféromètre peuvent également être utilisés pour améliorer la sensibilité autour de certaines fréquences.
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Guerlin, Christine. "Mesure quantique non destructive répétée de la lumière : états de Fock et trajectoires quantiques." Paris 6, 2007. https://tel.archives-ouvertes.fr/tel-00284379.
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Les postulats de la mesure quantique, définissant une mesure Quantique Non Destructive (QND), précisent que la perturbation minimale due à une mesure sur l’objet mesuré est une simple projection de l’état. Dans notre expérience d’électrodynamique quantique en cavité, le couplage fort entre atomes de Rydberg et photons micro-onde confinés dans une cavité supraconductrice produit des états intriqués: chaque système emporte une information sur l’état de l’autre. Dans le cas désaccordé, l’effet de l’interaction entres ces deux systèmes est un déphasage du dipôle de l’atome proportionnel au nombre de photons, que l’on peut détecter par interférométrie de Ramsey. Selon ce principe, nous avons pu, grâce au long temps de vie de notre cavité, réaliser une mesure QND répétée du nombre de photons. Nous avons observé pour la première fois les sauts quantiques de la lumière, et pu suivre la projection progressive d’un champ cohérent vers des états de Fock contenant jusqu’à sept photons.
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Penasa, Mariane. "Mesure au-delà de la limite quantique standard de l'amplitude d'un champ électromagnétique dans le domaine micro-onde." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066528/document.
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Intermédiaire essentiel au dialogue entre théorie et vérification expérimentale, la mesure n'a de sens que si la précision des résultats est élevée. La métrologie en laboratoire s'attache à augmenter autant que possible la précision avec laquelle l'expérimentateur a accès à la valeur d'un paramètre. Le bruit quantique affectant la mesure impose une limite sur la précision maximale accessible à partir d'états quasi-classiques: la limite quantique standard (SQL). La métrologie quantique cherche à utiliser les caractéristiques propres à la mécanique quantique pour la dépasser et se rapprocher le plus possible de la limite ultime, physiquement non franchissable, appelée limite de Heisenberg. Dans ce mémoire, nous avons développé une stratégie de mesure d'un champ électromagnétique contenant moins d'un photon basée sur l'utilisation de corrélations atome-champ dans une expérience d'électrodynamique quantique en cavité. L'idée est de mesurer l'amplitude de ce petit champ en sondant la perturbation qu'il introduit sur un état intriqué atome-champ mésoscopique déjà présent dans une cavité supraconductrice. Nous avons pu démontrer que le choix de notre mesure est, en principe, optimal grâce aux outils que sont l'information de Fisher (dépendant du processus de mesure) et l'information de Fisher dite quantique (qui elle n'en dépend pas), liées à la précision sur la mesure par des inégalités de type Cramér-Rao. Expérimentalement, nous avons très largement dépassé la précision obtenue sur l'amplitude du champ électromagnétique par une mesure classique et nous nous sommes rapprochés de la limite de Heisenberg autant que les imperfections expérimentales nous le permettaientAs an essential intermediary between theories and their experimental proofs, measurement is meaningfull if the precision of its results is high. The main emphasis of metrology in laboratories is therefore on increasing as much as possible the precision of the experimental evaluation of a parameter. Quantum noise that affects the measurement establishes a quantitative limit on the maximal precision that can be achieved with classical states: the standard quantum limit (SQL). Quantum metrology aims at using quantum features to beat this limit and to approach the physically ultimate limit called Heisenberg limit. This thesis presents a measurement strategy for an electromagnetic field containing less than one photon, which is based on the use of atom-field correlations in a cavity quantum electrodynamics experiment. The idea is to measure the amplitude of the small field by probing the disturbance caused on an entangled mesoscopic state that is already stored in the superconducting cavity. We demonstrated that our measurement strategy is in principle optimal thanks to two tools: the Fisher information (that depends on the measurement process) and the quantum Fisher information (that does not), which define the precision tanks to Cramér-Rao like equations. The measurement signal subsequently largely exceeded the level of accuracy obtained with classical states and we got as closed to the Heisenberg limit as the experimental imperfections allowed us
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Guerlin, Christine. "Mesure quantique non destructive répétée de la lunière: états de Fock et trajectoires quantiques." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2007. http://tel.archives-ouvertes.fr/tel-00284379.
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Les postulats de la mesure, définissant une mesure Quantique Non Destructive (QND), précisent que la perturbation minimale sur un objet mesuré est une projection de son état. Les appareils de mesure habituellement utilisés se situent largement au-delà de cette limite minimale. Les photodétecteurs usuels en particulier absorbent, donc détruisent, les photons qu'ils détectent. Dans notre expérience d'électrodynamique quantique en cavité, des atomes de Rydberg circulaires et des photons micro-onde confinés dans une cavité supraconductrice interagissent dans le régime de couplage fort. A l'issue de l'interaction les deux systèmes sont intriqués: chacun d'eux emporte une information sur l'autre. Dans le cas désaccordé, l'effet de l'interaction est un simple déplacement d'énergie des niveaux atomiques, résultant en un déphasage du dipôle proportionnel au nombre de photons, mesurable par interférométrie de Ramsey. Les atomes délivrent donc une information sur le nombre de photons présents dans le champ sans l'avoir modifié. Selon ce principe, nous avons pu grâce au long temps de vie de notre cavité réaliser une mesure QND répétée du nombre de photons. L'évolution du nombre de photons en présence de relaxation révèle alors des sauts brusques, appelés sauts quantiques. Notre expérience a permis la première observation de ce comportement pour la lumière. En décrivant à l'aide de la loi de Bayes l'information délivrée par chaque détection atomique, nous avons pu suivre la projection progressive d'un état cohérent vers des états de Fock contenant jusqu'à sept photons. L'analyse statistique de nos résultats fournit une très claire illustration des postulats de la mesure quantique.
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Crosnier, de Bellaistre Cécile. "Conductance et étalement d'une onde quantique dans un guide unidimensionnel : effet d'une force." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLO009/document.
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Dans un milieu désordonné, une onde peut être localisée exponentiellement par des effets d'interférence. Ce phénomène de localisation d'Anderson conduit notamment à une annulation de la conductance d'un fluide quantique unidimensionnel. Des travaux théoriques ont cependant montré que l'application d'un champ électrique pouvait réduire, voire supprimer, cette localisation. Nous étudions ici l'effet d'une force sur la localisation d'une onde quantique de matière dans un système unidimensionnel. En lien direct avec les expériences d'atomes ultrafroids, qui permettent d'observer la localisation d'Anderson d'un paquet d'onde en étalement, ou bien l'effet du désordre sur le transport entre deux réservoirs, nous nous intéressons à deux systèmes : la diffusion et la transmission d'une particule. Afin d'étudier la transmission à travers un guide, nous étendons un formalisme de matrices de transfert à la présence d'une force, éventuellement inhomogène. Deux approches analytiques complémentaires nous permettent d'étendre les résultats au cas d'un désordre de tavelures tel que celui utilisé dans les expériences d'atomes ultrafroids. Nous montrons que la force peut être entièrement prise en compte à l'aide d'une renormalisation de la longueur du guide par un libre parcours moyen local de la particule. Pour un désordre blanc, la force conduit alors une localisation plus faible, algébrique, tandis qu'une délocalisation apparaît pour un désordre corrélé. Nous nous intéressons ensuite à la diffusion d'une particule, à l'aide d'une approche numérique. Nous mettons en évidence une délocalisation de la position à grande force sous la forme d'une croissance temporelle algébrique, dont l'exposant augmente avec la force. Nous montrons de plus que la localisation est systématiquement détruite dans un désordre corréléA wave can be exponentially localized in a disordered medium, due to interference effects. This Anderson localization phenomenon leads to a cancellation of the conductance of a quantum fluid in 1D. However, theoretical works pointed out that an electric field may reduce or cancel this localization. We study here the effect of a force on the localization of a 1D quantum matter wave. Since both Anderson localization of an expanding wave packet and the effect of disorder on the transport between two reservoirs have been studied in ultracold atom experiments, we focus on two systems, namely the diffusion, or the transmission, of a particle.In order to calculate the transmission, we generalize a transfer matrix formalism to the presence of a, possibly inhomogeneous, force. The case of a speckle disorder as used in ultracold atom experiments is dealt with using two other analytical approaches. Our main is result is that the force can be entirely taken into account by renormalising the length with a local mean free path of the particle. For white-noise disorder, the force leads to a weaker, algebraic localization, whereas full delocalization appears for a correlated disorder. We then focus on the diffusion of a particle, using a numerical approach. A transition of delocalization of the particle for strong forces is shed into light through a power law increase of its position, whose exponent increases with the force. Moreover, we show that localization is systematically destroyed in a correlated disorder
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Zanthier, Joachim von. "Amplification par couches diélectriques d'une onde evanescente pour miroir atomique." Paris 6, 1995. http://www.theses.fr/1995PA066828.
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Métillon, Valentin. "Tomographie par trajectoires d'états délocalisés du champ micro-onde de deux cavités." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEE051.
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La reconstruction d'états quantiques, ou tomographie, joue un rôle central dans les technologies quantiques, afin de caractériser les opérations effectuées et d'extraire de l'information sur les états résultats de traitements d'information quantique. Les méthodes répandues de tomographie reposent généralement sur des mesures idéales, effectuées une seule fois sur chaque préparation de l'état d'intérêt. Dans ce travail, nous utilisons une nouvelle méthode, appelée tomographie par trajectoires, qui consiste à enregistrer, pour chaque réalisation de l'état, la trajectoire quantique suivie par le système à l'aide d'une série de mesures successives du système, en présence d'imperfections expérimentales et de décohérence. On extrait alors plus d'information sur l'état à reconstruire et on est capable, à partir d'un ensemble de mesures accessibles données, de créer des mesures plus générales. À l'aide des techniques de l'électrodynamique quantique en cavité, nous avons préparé des états intriqués de photons micro-onde délocalisés sur deux modes distants. Nous avons ensuite reconstruit ces états par tomographie par trajectoires, dans un espace de Hilbert de grande dimension. Nous montrons que cette méthode permet de reconstruire l'état, de développer des stratégies de mesure adaptées pour accélérer l'extraction d'information sur les cohérences quantiques d'intérêt et qu'elle fournit une estimation de l'incertitude sur les coefficients de la matrice densité reconstruiteQuantum state estimation, or tomography, is a key component of quantum technologies, allowing to characterise quantum operations and to extract information on the results of quantum information processes. The usual tomography techniques rely on ideal, single-shot measurements of the unknown state. In this work, we use a new approach, called trajectory quantum tomography, where the quantum trajectory of each realization of the state is recorded through a series of measurements, including experimental imperfections and decoherence. This strategy increases the extracted amount of information and allows to build new measurements for a set of feasible measurements.Using the tools of cavity quantum eletrodynamics, we have prepared entangled states of microwave photons spread on two separated modes. We have then performed a trajectory tomography of these states, in a large Hilbert space. We have proved that this method allows to estimate the state, to develop faster strategies for extracting information on specific coherences of the state and to compute error bars on the components of the estimated density matrix
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Thibault, Karl. "Corrélateur courant-courant dans le domaine temporel d'une jonction tunnel mesuré par spectroscopie micro-onde." Mémoire, Université de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/5351.
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Résumé : Ce mémoire rapporte les premières mesures de fluctuations de courant émises par une jonction tunnel sur une large bande passante, de 0.3 à 13 GHz, à une température très basse de 35 mK. Cela nous a permis de réaliser la spectroscopie (i.e. mesurer la dépendance en fréquence) du bruit thermique (tension de polarisation nulle, température variable), bruit de grenaille (basse température, tension de biais variable) et bruit photo-assisté (tension de polarisation AC). Grâce à la large bande passante de nos mesures, nous pouvons calculer le corrélateur courant-courant dans le domaine temporel. Nous observons le déclin thermique de ce corrélateur ainsi que ses oscillations de période h/eV, une conséquence directe du principe de Pauli sur le transport quantique. // Abstract : This thesis reports the first measurements of the current fluctuations emitted by a tunnel junction with a very wide bandwidth, from 0.3 to 13 GHz, down to very low temperature T=35 mK. This allowed us to perform the spectroscopy (i.e., measure the frequency dependence) of thermal noise (no dc bias, variable temperature), shot noise (low temperature, variable dc voltage bias) and photon-assisted noise (ac bias). Thanks to the very wide bandwidth of our measurement, we can deduce the current-current correlator in time domain. We observe the thermal decay of this correlator as well as its oscillations with a period h/eV, a direct consequence of the effect of the Pauli principle in quantum transport.
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Renaudat, Saint-Jean Margaux. "Laser à cascade quantique dans un guide micro-onde pour la réalisation d'un peigne de fréquence." Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCC094.
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Le laser à cascade quantique (LCQ) est un dispositif compact unipolaire qui repose sur des transitions optiques entre les états quantifiés de la bande de conduction de puits quantiques. Sa longueur d'onde d'émission, facilement ajustable par une ingénierie de bandes, peut couvrir toute la gamme du moyen infrarouge. Les travaux réalisés pendant cette thèse portent sur la conception de nouvelles géométries de cavité afin de réaliser un peigne de fréquence. La majeure partie du travail de cette thèse a été d'améliorer la stabilisation et le contrôle de l'espacement entre les modes optiques dans la cavité Fabry-Perot d'un LCQ émettant à 9µm. En combinant les technologies des micro-ondes et des semiconducteurs, nous démontrons la génération d'un peigne de fréquence grâce à l'intégration d'une ligne micro-ruban (MR) dans une cavité d'un LCQ. Une étude comparative a été réalisée entre cette nouvelle géométrie et une géométrie standard. La stabilité de l'espacement entre les modes a été caractérisée en mesurant la composante hyperfréquence du signal optique à la fréquence d'aller-retour (AR) des photons. La largeur à mi-hauteur de ce signal est dix-sept fois plus faible que celle mesurée pour un LCQ standard pour une puissance optique de sortie similaire, preuve d'une meilleure stabilité dans la cavité. Grâce à l'injection d'un signal hyperfréquence stable à cette fréquence d'AR, nous contrôlons et stabilisons le peigne de fréquence sur une plage de l'ordre du MHz avec une puissance injectée de 10 mW. Les réponses à une modulation directe des dispositifs ont également été étudiées : la bande passante du laser MR est trois fois supérieure à celle d'un laser à standard à 10 GHzQuantum cascade lasers (QCLs) are unipolar compact devices based on optical transitions in quantum wells between the quantized states of the conduction band. Their emission wavelength, easily tailored thanks to quantum engineering, can cover the entire range of the mid-infrared spectrum. The work presented in this thesis deals with the design and the study of new cavity architectures for the realization of a frequency comb. Aim of the work is to improve the stability and the control of the intermode frequency spacing of Fabry-Perot QCL emitting at 9 ktm. By merging microwave and semiconductor laser technologies, we demonstrate the generation of a stable frequency comb, integrating a microstrip line in the QCL cavity. A comparative study of the new architecture and standard design has been carried out. The stability of the spacing between the modes has been characterized by measuring the microwave component of the optical signal at the round-trip frequency of photons in the cavity (13. 7 GHz). Full width at half maximum of this signal is seventeen times lower than that measured for a standard QCL with similar optical power, evidence of improved stability in the optical cavity. Through the injection of a stable microwave signal at the round-trip frequency, we control and stabilize the frequency comb over a range of the order of MHz with an injected power of 10 mW. The performance of direct modulation of the devices has been also investigated : the measured bandpass of the microstrip laser is three times higher than the standard laser at 10 GHz
Books on the topic "Onde quantique"
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McTaggart, Lynne. The field: The quest for the secret force of the universe. New York: Quill, 2003.
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Mctaggart, Lynne. The Field: The Quest for the Secret Force of the Universe. Harper Paperbacks, 2003.
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Mctaggart, Lynne. The Field: The Quest for the Secret Force of the Universe. Harper Paperbacks, 2003.
Find full textBook chapters on the topic "Onde quantique"
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Brandt, Siegmund, and Hans Dieter Dahmen. "Quantile Motion in One Dimension." In The Picture Book of Quantum Mechanics, 129–44. New York, NY: Springer New York, 2001. http://dx.doi.org/10.1007/978-1-4613-0167-7_7.
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Brandt, Siegmund, and Hans Dieter Dahmen. "Quantile Motion in One Dimension." In The Picture Book of Quantum Mechanics, 141–56. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-3951-6_7.
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"Dualité onde/particule." In La théorie quantique en images, 105. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-1697-2-059.
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"Dualité onde/particule." In La théorie quantique en images, 105. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-1697-2.c059.
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"La vitesse de propagation d’une onde." In La théorie quantique en images, 107. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-1697-2-061.
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"La vitesse de propagation d’une onde." In La théorie quantique en images, 107. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-1697-2.c061.
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Cohen-Tannoudji, Claude, Bernard Diu, and Franck Laloë. "15 Mécanique quantique." In Ondes, matière et Univers, 435–50. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-2265-2.c022.
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"Les propriétés des ondes." In La théorie quantique en images, 106. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-1697-2-060.
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"Les propriétés des ondes." In La théorie quantique en images, 106. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-1697-2.c060.
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"3. Ondes et particules." In Quantique : au-delà de l'étrange, 25–44. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-2411-3-004.
Full textConference papers on the topic "Onde quantique"
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Zhou, Fan, Zhoufan Zhu, Qi Kuang, and Liwen Zhang. "Non-decreasing Quantile Function Network with Efficient Exploration for Distributional Reinforcement Learning." In Thirtieth International Joint Conference on Artificial Intelligence {IJCAI-21}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/ijcai.2021/476.
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Although distributional reinforcement learning (DRL) has been widely examined in the past few years, there are two open questions people are still trying to address. One is how to ensure the validity of the learned quantile function, the other is how to efficiently utilize the distribution information. This paper attempts to provide some new perspectives to encourage the future in-depth studies in these two fields. We first propose a non-decreasing quantile function network (NDQFN) to guarantee the monotonicity of the obtained quantile estimates and then design a general exploration framework called distributional prediction error (DPE) for DRL which utilizes the entire distribution of the quantile function. In this paper, we not only discuss the theoretical necessity of our method but also show the performance gain it achieves in practice by comparing with some competitors on Atari 2600 Games especially in some hard-explored games.
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Pavy, Anne M., and Brian D. Rigling. "Phase modulated radar waveform classification using quantile one-class SVMs." In 2015 IEEE International Radar Conference (RadarCon). IEEE, 2015. http://dx.doi.org/10.1109/radar.2015.7131095.
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Cui, Yufei, Ziquan Liu, Wuguannan Yao, Qiao Li, Antoni B. Chan, Tei-wei Kuo, and Chun Jason Xue. "Fully Nested Neural Network for Adaptive Compression and Quantization." In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/288.
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Neural network compression and quantization are important tasks for fitting state-of-the-art models into the computational, memory and power constraints of mobile devices and embedded hardware. Recent approaches to model compression/quantization are based on reinforcement learning or search methods to quantize the neural network for a specific hardware platform. However, these methods require multiple runs to compress/quantize the same base neural network to different hardware setups. In this work, we propose a fully nested neural network (FN3) that runs only once to build a nested set of compressed/quantized models, which is optimal for different resource constraints. Specifically, we exploit the additive characteristic in different levels of building blocks in neural network and propose an ordered dropout (ODO) operation that ranks the building blocks. Given a trained FN3, a fast heuristic search algorithm is run offline to find the optimal removal of components to maximize the accuracy under different constraints. Compared with the related works on adaptive neural network designed only for channels or bits, the proposed approach is applicable to different levels of building blocks (bits, neurons, channels, residual paths and layers). Empirical results validate strong practical performance of proposed approach.
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Derbanne, Quentin, Guillaume de Hauteclocque, and Martin Dumont. "How to Account for Short-Term and Long-Term Variability in the Prediction of the 100 Years Response?" In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61701.
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Current practices in offshore unit design are based on the prediction of the 100 years response (tension, offset, stress...). The methodologies described in various standards (ISO, API...) are all very similar: several design environments are described with a combination of sea state, wind and current. Usually envelope contours are used, describing a set of environmental conditions corresponding to a 100 years return period. These design conditions are supposed to produce the highest responses. A time domain (or sometimes frequency domain) simulation is done on each of these short-term conditions, and the 3h most probable maximum (MPM) is computed for each. The highest MPM over all the design conditions is taken as the 100 years response. This approach completely neglects the short-term variability of the response. This paper compares several design methods with the exact 100 years response. The exact 100 years response is computed by integrating the conditional short-term distributions with respect to the probability density function of the environmental conditions. The various design methods are all based on a simplification of an Inverse First Order Reliability Method (IFORM) approach, which requires computing one or several design conditions corresponding to one or several return periods, each of these conditions being associated with a given short-term quantile. Computations are done using two datasets. At first realistic line tensions of 7 offshore units are used, based on a large number of simulations with a mooring software. On a second stage a more general parametric model using a Weibull distribution to describe the long-term variability and a Gumbel distribution to describe the short-term distribution of the 3h maximum is used. It is shown that the current methods are unconservative with respect to the exact 100 years response. A more accurate method is proposed, based on a 40 years return period associated with the quantile 90% and a correction factor of 1.04.
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Hamid, Aamna, Zumin Shi, and Lukman Thalib. "Association between Soft Drink Consumption and Bone Mineral Density among Qatari Women- Analysis of Qatar Biobank data." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0182.
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Background: Decrease in bone mineral density (BMD) increases the risk of osteopenia and osteoporosis. It is common in older women, as the BMD tends to decrease with age, particularly after menopause. While age and hormonal changes are well-established risk factors, other factors have been investigated for possible links to increase the risk of osteoporosis. These factors include dietary patterns and lifestyle. Aim: To explore the association between soft drink consumption and BMD. Method: This cross-sectional study included data from 1000 Qatari women age ≥ 40 year’s participated in the Qatar Biobank Study. BMD levels were measured using the Dual-Energy X-ray Absorptiometry (DXA) scan and the soft drink consumption was assessed using a food frequency questionnaires. Multiple quantile regression models were used to assess the association between bone mineral density and soft drink consumption. Results: While most of the participants did not drink soft drinks (68%), around one third reported consuming soft drinks. A total of 16.4% of participants reported consuming soft drinks < 1 time/ week and 15.6% of participants reported consuming soft drinks ≥ 1 time/ week. There was an inverse association between BMD and soft drink consumption. Compared with non-consumers, ≥ 1 time/week consumption of soft drink had a -0.034 95%CI (-0.056, -0.012) at 0.25 quantile for BMD after adjusting for age, BMI, menopausal status, smoking status, physical activities, milk intake, and fruit and vegetable consumption. Also, BMD was negatively associated with regular soft drinks, but not with diet soft drink and energy drink. Conclusion: High consumption of soft drink is inversely related to BMD among Qatari women. Further longitudinal and clinical studies are required before developing public health intervention to improve bone health by reducing soft drink consumption.
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Maslak, Mariusz, and Tomasz Domanski. "Design value of a headed stud shear resistance in composite steel – concrete beams – probability-based approach to evaluation." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.6950.
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Conventional standard procedure used to determine the design value of a headed stud shear resistance in composite steel-concrete beams is very simple but, in fact, mathematically incorrect, particularly in the case when such connector is automatically welded and when it is working in a solid slab. According to this approach the considered value is specified as a minimum of two separate design values. One of them is related to the resistance of the stud itself while the other is associated with the failure of the surrounding concrete. In the paper presented by the authors a new algorithm which allow to evaluate this value is recommended and discussed in detail. It seems to be more accurate because it is based on the fully probabilistic inference. In such approach a new random variable is introduced, being a minimum of two other, statistically independent, random variables. Analogously as it is in the concept previously mentioned, the first random variable quantifies now the steel stud shear resistance whereas the second one – the resistance of the adjacent concrete. Consequently, the sought design value is determined as a suitable quantile of this new random variable, characterized by log-normal probability distribution. It is shown that the design value of a headed stud shear resistance, calculated in this manner, strongly depends on the variability of strength parameters, relating both to the steel of which the connecting stud is made and to the concrete of the slab. In addition, it is found that in the case when the variability of concrete strength is too high, the safety factor recommended to use in European standards is not able to provide the required safety level, acceptable by the building users. The considerations presented in the article are illustrated by a detailed computational example.
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Sankaranarayanan, Bhuvaneswari, Aria Abubakar, David F. Allen, and Ivan Diaz Granados. "Automating the Log Interpretation Workflow Using Machine Learning." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205950-ms.
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Abstract Log interpretation is the task of analyzing and processing well logs to generate the subsurface properties around wells. A direct application of machine learning (ML) to this task is to train an ML model for predicting properties in target wells given well logs (data) and properties (labels) in a set of training wells in the same field and/or region. Our ML model of choice for predicting the desired properties is the decision tree-based learning algorithm called random forests (RF). We also devise a mechanism to automatically tune the hyperparameters of this algorithm depending on the data in the training wells. This eliminates the tedious task of carefully tuning the hyperparameters for every new set of training wells and provides a one-click solution. In addition to predicting the properties, we compute the uncertainty in the predicted properties in the form of prediction intervals using the concept of quantile regression forests (QRF). We test our workflow on two use cases. First, we consider a petrophysics use case on an unconventional land dataset to predict the petrophysical properties such as water saturation, total porosity, volume of clay, and total organic carbon from petrophysics logs. Then, we consider a geomechanics use case on a conventional offshore dataset to predict the lithology, pore pressure, and rock mechanical properties. We obtain a good prediction performance on both use cases. The uncertainty estimates also complement the ML model's prediction of the properties by explaining the various correlations that are found to be existing among them based on domain knowledge. The entire workflow of automating the tuning of hyperparameters and training the ML model to predict the properties along with its estimate of uncertainty provide a complete solution to apply the ML workflow for automated log interpretation.
Reports on the topic "Onde quantique"
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Over, Thomas, Riki Saito, Andrea Veilleux, Padraic O’Shea, Jennifer Sharpe, David Soong, and Audrey Ishii. Estimation of Peak Discharge Quantiles for Selected Annual Exceedance Probabilities in Northeastern Illinois. Illinois Center for Transportation, June 2016. http://dx.doi.org/10.36501/0197-9191/16-014.
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This report provides two sets of equations for estimating peak discharge quantiles at annual exceedance probabilities (AEPs) of 0.50, 0.20, 0.10, 0.04, 0.02, 0.01, 0.005, and 0.002 (recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively) for watersheds in Illinois based on annual maximum peak discharge data from 117 watersheds in and near northeastern Illinois. One set of equations was developed through a temporal analysis with a two-step least squares-quantile regression technique that measures the average effect of changes in the urbanization of the watersheds used in the study. The resulting equations can be used to adjust rural peak discharge quantiles for the effect of urbanization, and in this study the equations also were used to adjust the annual maximum peak discharges from the study watersheds to 2010 urbanization conditions. The other set of equations was developed by a spatial analysis. This analysis used generalized least-squares regression to fit the peak discharge quantiles computed from the urbanization-adjusted annual maximum peak discharges from the study watersheds to drainage-basin characteristics. The peak discharge quantiles were computed by using the Expected Moments Algorithm following the removal of potentially influential low floods defined by a multiple Grubbs-Beck test. To improve the quantile estimates, regional skew coefficients were obtained from a newly developed regional skew model in which the skew increases with the urbanized land use fraction. The skew coefficient values for each streamgage were then computed as the variance-weighted average of at-site and regional skew coefficients. The drainage-basin characteristics used as explanatory variables in the spatial analysis include drainage area, the fraction of developed land, the fraction of land with poorly drained soils or likely water, and the basin slope estimated as the ratio of the basin relief to basin perimeter. This report also provides: (1) examples to illustrate the use of the spatial and urbanization-adjustment equations for estimating peak discharge quantiles at ungaged sites and to improve flood-quantile estimates at and near a gaged site; (2) the urbanization-adjusted annual maximum peak discharges and peak discharge quantile estimates at streamgages from 181 watersheds including the 117 study watersheds and 64 additional watersheds in the study region that were originally considered for use in the study but later deemed to be redundant. The urbanization-adjustment equations, spatial regression equations, and peak discharge quantile estimates developed in this study will be made available in the web-based application StreamStats, which provides automated regression-equation solutions for user-selected stream locations. Figures and tables comparing the observed and urbanization-adjusted peak discharge records by streamgage are provided at http://dx.doi.org/10.3133/sir20165050 for download.