Gotowe bibliografie tematyczne / Large scale oscillations

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Gotowa bibliografia na temat „Large scale oscillations”

Autor: Grafiati

Data publikacji: 6 września 2023

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Artykuły w czasopismach na temat "Large scale oscillations"

Shen, Yuandeng. "Multi-wavelength observations of filament oscillations induced by shock waves". Proceedings of the International Astronomical Union 11, S320 (sierpień 2015): 106–8. http://dx.doi.org/10.1017/s1743921316000193.

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AbstractTwo cases of filament oscillations induced by large-scale coronal shock waves are presented. For the first case, a chain of transverse oscillating filaments are observed in a proper order after the passing of a shock wave, and it is found that the they were triggered by the surface component of the dome-shaped shock wave. For the second case, simultaneous transverse oscillation of a limb prominence and longitudinal oscillation in an on-disk filament are launched by a single shock wave. It is found that the interaction angle between the shock wave and the prominence axis is the key to launch transverse or longitudinal filament oscillations. In addition, filament magnetic fields are estimated, using the measured parameters.

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Garcia, Javier O., Emily D. Grossman i Ramesh Srinivasan. "Evoked potentials in large-scale cortical networks elicited by TMS of the visual cortex". Journal of Neurophysiology 106, nr 4 (październik 2011): 1734–46. http://dx.doi.org/10.1152/jn.00739.2010.

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Single pulses of transcranial magnetic stimulation (TMS) result in distal and long-lasting oscillations, a finding directly challenging the virtual lesion hypothesis. Previous research supporting this finding has primarily come from stimulation of the motor cortex. We have used single-pulse TMS with simultaneous EEG to target seven brain regions, six of which belong to the visual system [left and right primary visual area V1, motion-sensitive human middle temporal cortex, and a ventral temporal region], as determined with functional MRI-guided neuronavigation, and a vertex “control” site to measure the network effects of the TMS pulse. We found the TMS-evoked potential (TMS-EP) over visual cortex consists mostly of site-dependent theta- and alphaband oscillations. These site-dependent oscillations extended beyond the stimulation site to functionally connected cortical regions and correspond to time windows where the EEG responses maximally diverge (40, 200, and 385 ms). Correlations revealed two site-independent oscillations ∼350 ms after the TMS pulse: a theta-band oscillation carried by the frontal cortex, and an alpha-band oscillation over parietal and frontal cortical regions. A manipulation of stimulation intensity at one stimulation site (right hemisphere V1-V3) revealed sensitivity to the stimulation intensity at different regions of cortex, evidence of intensity tuning in regions distal to the site of stimulation. Together these results suggest that a TMS pulse applied to the visual cortex has a complex effect on brain function, engaging multiple brain networks functionally connected to the visual system with both invariant and site-specific spatiotemporal dynamics. With this characterization of TMS, we propose an alternative to the virtual lesion hypothesis. Rather than a technique that simulates lesions, we propose TMS generates natural brain signals and engages functional networks.

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FUNFSCHILLING, DENIS, ERIC BROWN i GUENTER AHLERS. "Torsional oscillations of the large-scale circulation in turbulent Rayleigh–Bénard convection". Journal of Fluid Mechanics 607 (30.06.2008): 119–39. http://dx.doi.org/10.1017/s0022112008001882.

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Measurements over the Rayleigh-number range 108 ≲ R ≲ 1011 and Prandtl-number range 4.4≲σ≲29 that determine the torsional nature and amplitude of the oscillatory mode of the large-scale circulation (LSC) of turbulent Rayleigh–Bénard convection are presented. For cylindrical samples of aspect ratio Γ=1 the mode consists of an azimuthal twist of the near-vertical LSC circulation plane, with the top and bottom halves of the plane oscillating out of phase by half a cycle. The data for Γ=1 and σ=4.4 showed that the oscillation amplitude varied irregularly in time, yielding a Gaussian probability distribution centred at zero for the displacement angle. This result can be described well by the equation of motion of a stochastically driven damped harmonic oscillator. It suggests that the existence of the oscillations is a consequence of the stochastic driving by the small-scale turbulent background fluctuations of the system, rather than a consequence of a Hopf bifurcation of the deterministic system. The power spectrum of the LSC orientation had a peak at finite frequency with a quality factor Q≃5, nearly independent of R. For samples with Γ≥2 we did not find this mode, but there remained a characteristic periodic signal that was detectable in the area density ρp of the plumes above the bottom-plate centre. Measurements of ρp revealed a strong dependence on the Rayleigh number R, and on the aspect ratio Γ that could be represented by ρp ~ Γ2.7±0.3. Movies are available with the online version of the paper.

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Haegeli, Pascal, Bret Shandro i Patrick Mair. "Using avalanche problems to examine the effect of large-scale atmosphere–ocean oscillations on avalanche hazard in western Canada". Cryosphere 15, nr 3 (29.03.2021): 1567–86. http://dx.doi.org/10.5194/tc-15-1567-2021.

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Abstract. Numerous large-scale atmosphere–ocean oscillations including the El Niño–Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Pacific North American Teleconnection Pattern (PNA), and the Arctic Oscillation (AO) are known to substantially affect winter weather patterns in western Canada. Several studies have examined the effect of these oscillations on avalanche hazard using long-term avalanche activity records from highway avalanche safety programmes. We present a new approach for gaining additional insight into these relationships that uses avalanche problem information published in public avalanche bulletins during the winters of 2010 to 2019. For each avalanche problem type, we calculate seasonal prevalence values for each forecast area, elevation band, and season, which are then included in a series of beta mixed-effects regression models to explore both the overall and regional effects of the Pacific-centered oscillations (POs; including ENSO, PDO, and PNA) and AO on the nature of avalanche hazard in the study area. We find significant negative effects of PO on the prevalence of storm slab avalanche problems, wind slab avalanche problems, and dry loose avalanche problems, which agree reasonably well with the known impacts of PO on winter weather in western Canada. The analysis also reveals a positive relationship between AO and the prevalence of deep persistent slab avalanche problems, particularly in the Rocky Mountains. In addition, we find several smaller-scale patterns that highlight that the avalanche hazard response to these oscillations varies regionally. Even though our study period is short, our study shows that the forecaster judgement included in avalanche problem assessments can add considerable value for these types of analyses. Since the predictability of the most important atmosphere–ocean oscillations is continuously improving, a better understanding of their effect on avalanche hazard can contribute to the development of informative seasonal avalanche forecasts in a relatively simple way.

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Restrepo, Juan Camilo, Aldemar Higgins, Jaime Escobar, Silvio Ospino i Natalia Hoyos. "Contribution of low-frequency climatic–oceanic oscillations to streamflow variability in small, coastal rivers of the Sierra Nevada de Santa Marta (Colombia)". Hydrology and Earth System Sciences 23, nr 5 (16.05.2019): 2379–400. http://dx.doi.org/10.5194/hess-23-2379-2019.

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Abstract. This study evaluated the influence of low-frequency oscillations, that are linked to large-scale oceanographic–atmospheric processes, on streamflow variability in small tropical coastal mountain rivers of the Sierra Nevada de Santa Marta, Colombia. We used data from six rivers that had > 32 years of complete, continuous monthly streamflow records. This investigation employed spectral analyses to (1) explore temporal characteristics of streamflow variability, (2) estimate the net contribution to the energy spectrum of low-frequency oscillations to streamflow anomalies, and (3) analyze the linkages between streamflow anomalies and large-scale, low-frequency oceanographic–atmospheric processes. Wavelet analyses indicate that the 8–12-year component exhibited a quasi-stationary state, with a peak of maximum power between 1985 and 2005. These oscillations were nearly in phase in all rivers. Maximum power peaks occurred for the Palomino and Rancheria rivers in 1985 and 1995, respectively. The wavelet spectrum highlights a change in river variability patterns between 1995 and 2015, characterized by a shift towards the low-frequency oscillations' domain (8–12 years). The net contribution of these oscillations to the energy spectrum was as high as 51 %, a value much larger than previously thought for rivers in northwestern South America. The simultaneous occurrence of hydrologic oscillations, as well as the increase in the amplitude of the 8–12-year band, defined periods of extremely anomalous wet seasons during 1989–1990, 1998–2002 and 2010–2011, reflecting the role of low-frequency oscillations in modulating streamflow variability in these rivers. Cross-wavelet transform and wavelet coherence revealed high common powers and significant coherences in low-frequency bands (>96 months) between streamflow anomalies and Atlantic Meridional Oscillation (AMO), Pacific Decadal Oscillation (PDO) and the Tropical North Atlantic Index (TNA). These results show the role of large-scale, low-frequency oceanographic–climate processes in modulating the long-term hydrological variability of these rivers.

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Švestka, Zdeněk. "Slow-mode oscillations of large-scale coronal loops". Solar Physics 152, nr 2 (lipiec 1994): 505–8. http://dx.doi.org/10.1007/bf00680454.

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Schwarze, Rüdiger, Antje Rückert, Ronny Leonhardt i Frank Obermeier. "Large Scale Oscillations in the Continuous Casting Process". PAMM 5, nr 1 (grudzień 2005): 479–80. http://dx.doi.org/10.1002/pamm.200510216.

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Yang, Dandan, Yanfeng Gao, Ming Yu, Xiaoping Wen i Ming-Xiang Zhao. "Analysis of drag reduction effects in turbulent Taylor–Couette flow controlled via axial oscillation of inner cylinder". Physics of Fluids 34, nr 4 (kwiecień 2022): 045111. http://dx.doi.org/10.1063/5.0087966.

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Analysis of drag reduction effects due to axial oscillation of an inner cylinder in a turbulent Taylor–Couette (TC) flow is performed in the present study. The frictional Reynolds number on the inner cylinder is 218, and the non-dimensional oscillating period is varied from 8 to 32. By examining turbulence statistics, we uncover different impacts of the long- and short-period oscillations on the circumferential ( θ) and radial ( r) velocity fluctuations in large ([Formula: see text]) and small ([Formula: see text]) scales. One of the most surprising findings is that the short-period oscillation increases the large-scale Reynolds shear stress [Formula: see text] by the strong intensification of [Formula: see text] exceeding the suppression of [Formula: see text]. To understand the phenomena, the spectra of each term in the transport equations of the Reynolds normal stresses [Formula: see text] and [Formula: see text] are analyzed. First, it is shown that the short-period oscillation weakens the productions of [Formula: see text], and [Formula: see text] while it enhances that of [Formula: see text]. In contrast, the long-period oscillation reduces the productions of [Formula: see text] and [Formula: see text] while it mainly intensifies that of [Formula: see text]. Second, the investigations of the pressure–strain terms indicate that the short-period oscillation mainly impedes the inter-component energy transfer originating from the small-scale background turbulence. However, the long-period oscillation benefits the small-scale inter-component energy communication while it hinders the large-scale one. In addition, the inverse energy transfer in the turbulent TC flow is confirmed by inspecting the inter-scale energy transfer terms. The hindrance of the inter-scale energy transfer by the inner-cylinder oscillation plays a non-negligible role in the reduction of the wall friction drag.

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Shao, Jun, Jun Wang, Sunyun Lv i Jianping Bing. "Spatial and temporal variability of seasonal precipitation in Poyang Lake basin and possible links with climate indices". Hydrology Research 47, S1 (3.05.2016): 51–68. http://dx.doi.org/10.2166/nh.2016.249.

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Based on the precipitation data of 21 meteorological stations in Poyang Lake basin, the temporal and spatial variability of seasonal precipitation was analyzed by wavelet analysis method. This study adopted the cross wavelet transform to analyze the correlation between the seasonal precipitation and climate indices in time and frequency scales, discussed the possible links between its precipitation variations and climate indices, and preliminarily analyzed its mechanism and regular pattern of variation. The results showed that the oscillations in 2–4 years' and 4–8 years' bands were the main variation periods of seasonal precipitation in Poyang Lake basin. In the 2–4 years' band, the years of rainfall peaks appearing in Poyang Lake were basically consistent with the years when El Niño appeared, and the precipitation oscillations in summer appeared more dramatic in space. According to analysis on the cross wavelet power spectra between different seasonal rainfalls and climate indices, certain correlations between climate factors and seasonal precipitation had existed in specific time periods. Large-scale climate oscillations like the El Niño/Southern Oscillation, North Atlantic Oscillation, Indian Ocean Dipole, and Pacific Decadal Oscillation caused the variability of large-scale circulations through their respective independent or inter-coupled climate systems, and affected the precipitation distribution in Poyang Lake basin by changing local climate conditions like the East Asian Monsoon.

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Jiang, Peng, Zhongbo Yu i Kumud Acharya. "Drought in the Western United States: Its Connections with Large-Scale Oceanic Oscillations". Atmosphere 10, nr 2 (16.02.2019): 82. http://dx.doi.org/10.3390/atmos10020082.

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In this paper, we applied the Empirical Orthogonal Function (EOF) analysis on a drought index expressed as consecutive dry days (CDD) to identify the drought variability in western United States. Based on the EOF analysis, correlation maps were generated between the leading principle component (PC) of seasonal CDD and sea surface temperature (SST) anomalies to explore the dynamic context of the leading modes in CDD. The EOF analysis indicates that the spatiotemporal pattern of winter CDD is related to an integrated impact from El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Atlantic Multi-decadal Oscillation (AMO), while summer CDD is mainly controlled by PDO phases. We also calculated seasonal CDD anomalies during selected climatic phases to further evaluate the impacts of large-scale oceanic oscillation on the spatial pattern of droughts. We found that AMO+/PDO− will contribute to a consistent drought condition during the winter in the western United States. El Niño will bring a dry winter to the northern part of western United States while La Niña will bring a dry winter to the southern part. During El Niño years, the drought center changes with the type of El Niño events. Considering the future states of the examined ocean oscillations, we suggest possible drier than normal conditions in the western United States for upcoming decades, and moreover, an intensified drought for the coast areas of the north Pacific region and upper Mississippi River Basin.

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Rozprawy doktorskie na temat "Large scale oscillations"

Xu, Xiaoying. "Robust Measurement of the Cosmic Distance Scale Using Baryon Acoustic Oscillations". Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/241935.

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We present techniques for obtaining precision distance measurements using the baryon acoustic oscillations (BAO) through controlling systematics and reducing statistical uncertainties. Using the resulting distance-redshift relation, we can infer cosmological parameters such as w, the equation of state of dark energy. We introduce a new statistic, ɷ(l)(r(s)), for BAO analysis that affords better control over systematics. It is computed by band-filtering the power spectrum P(k) or the correlation function ξ(r) to extract the BAO signal. This is conducive to several favourable outcomes. We compute ɷ(l)(r(s)) from 44 simulations and compare the results to P(k) and ξ(r). We find that the acoustic scales and theoretical errors we measure are consistent between all three statistics. We demonstrate the first application of reconstruction to a galaxy redshift survey. Reconstruction is designed to partially undo the effects of non-linear structure growth on the BAO, allowing more precise measurements of the acoustic scale. We also present a new method for deriving a smooth covariance matrix based on a Gaussian model. In addition, we develop and perform detailed robustness tests on the ξ(r) model we employ to extract the BAO scale from the data. Using these methods, we obtain spherically-averaged distances to z = 0.35 and z = 0.57 from SDSS DR7 and DR9 with 1.9% and 1.7% precision respectively. Combined with WMAP7 CMB observations, SNLS3 data and BAO measurements from 6dF, we measure w = -1.08 ± 0.08 assuming a wCDM cosmology. This represents a ~8% measurement of w and is consistent with a cosmological constant.The preceding does not capture the expansion history of the universe, H(z), encoded in the line-of-sight distance scale. To disentangle H(z), we exploit the anisotropic BAO signal that arises if we assume the wrong cosmology when calculating the clustering distribution. Since we expect the BAO signal to be isotropic, we can use the magnitude of the anisotropy to separately measure H(z) and D(A)(z). We apply our simple models to SDSS DR7 data and obtain a ~3.6% measurement of D(A)(z=0.35) and a ~8.4% measurement of H(z = 0.35).

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Seo, Hee-Jong. "High-Precision Large-Scale Structure: The Baryon Acoustic Oscillations and Passive Flow". Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194697.

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We present a precision study of large-scale structure from large galaxy redshift surveys. We focus on two main subjects of large-scale structure: precisioncosmology with baryon acoustic oscillations from large galaxy surveys and the evolution of galaxy clustering for passively flowing galaxies.The baryon acoustic oscillations in galaxy redshift surveys can serve as an efficient standard ruler to measure the cosmological distance scale, i.e., theangular diameter distances and Hubble parameters, as a function of redshift, and therefore dark energy parameters. We use a Fisher matrix formalism to show that such a standard ruler tests can constrain the angular diameter distances and Hubble parameters to a precision of a few percent, thereby providing robust measurements of present-day dark energy density and its time-dependence.We use N-body simulations to investigate possible systematic errors in the recovery of the cosmological distance scale from galaxy redshift surveys. We show that the baryon signature on linear and quasi-linear scales is robust against nonlinear growth, redshift distortions, and halo (or galaxy) bias, albeit partial obscuration of the signature occurs due to nonlinear growth and redshift distortions.We present the improved Fisher matrix formalism which incorporates the Lagrangian displacement field to describe the nonlinear effects on baryon signature as a function of time and scale. We present a physically motivated, reduced 2-dimensional fitting formula for the full Fisher matrix formalism. We show that distance precision from the revised formalism is in excellent agreement with distance precision from N-body simulations.Finally, we present a numerical study of the evolution of galaxy clustering when galaxies flow passively from high redshift to low redshift, that is, without merging or new formations. We show that passive flow evolution induces interesting characteristics in the galaxy distribution at low redshift: we find an asymptotic convergence in galaxy clustering and halo occupation distribution regardless of the initial distribution of galaxies.

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Shi, Guangyu. "Nonlinear static and dynamic analyses of large-scale lattice-type structures and nonlinear active control by piezo actuators". Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/19176.

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Comparat, Johan. "Baryonic acoustic oscillations with emission line galaxies at intermediate redshift : the large-scale structure of the universe". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4720/document.

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J'ai démontrer la faisabilité de la sélection de la cible pour les galaxies en ligne des émissions lumineuses. Je comprends maintenant les principaux mécanismes physiques de conduite de l'efficacité d'une sélection, en particulier le rapport à la photométrie de parent. Une question reste perplexe, je ne pouvais pas encore estimer quantitativement l'impact de la poussière sur l'efficacité de la sélection. J'espère que d'aborder cette question avec l'ensemble des données décrites dans le chapitre 4.En dehors de la ligne de sélection de la cible de la galaxie d'émission, j'ai étudié, au premier ordre, les deux principales erreurs systématiques sur la détermination de l'échelle BAO nous attendent en raison de l'utilisation galaxies en ligne des émissions comme traceurs de la question. J'ai d'abord montré le caractère incomplet de la distribution redshift, en raison de la mesure du décalage spectral avec [Oii], est lié à la résolution instrumentale. Je trouve qu'il ya deux régimes intéressants. Pour une observation des plus brillants [OII] émetteurs, une résolution modérée est suffisante, alors que pour une enquête plus faible, la plus haute de la résolution le meilleur. Deuxièmement, j'ai estimé le biais de la galaxie linéaire des sélections discuté avant et je trouve qu'ils sont très biaisés. D'une part, ce sont d'excellentes nouvelles pour les observateurs, comme le temps nécessaire pour observer à un signal donné au bruit dans le spectre de puissance diminue avec le carré de la partialité. D'autre part, elle constitue un nouveau défi pour les algorithmes de reconstruction et la fabrication de catalogues simulacres
In this PhD, I demonstrate the feasibility of the target selection for bright emission line galaxies. Also I now understand the main physical mechanisms driving the efficiency of a selection, in particular the relation to the parent photometry. A puzzling issue remains, I could not yet estimate quantitatively the impact of the dust on the selection efficiency. I hope to address this question with the data set described in chapter 4.Apart from the emission line galaxy target selection, I investigated, at first order, the two main systematic errors on the determination of the BAO scale we expect due to using emission line galaxies as tracers of the matter. First I showed the incompleteness in the redshift distribution, due to the measurement of the redshift with [Oii], is related to the instrumental resolution. I find there are two interesting regimes. For an observation of the brightest [Oii]emitters, a moderate resolution is sufficient, whereas for a fainter survey, the highest the resolution the best. Secondly, I estimated the linear galaxy bias of the selections discussed before and I find they are highly biased. On one hand, this is great news for the observers, as the time required to observed at a given signal to noise in the power spectrum decreases with the square of the bias. On the other hand, it constitutes a new challenge for reconstruction algorithms and the making of mock catalogs. The work in progress described in the last chapter shows I am starting to try and handle these questions in a robust manner

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Molina, Diogenes. "Intelligent control and system aggregation techniques for improving rotor-angle stability of large-scale power systems". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50291.

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A variety of factors such as increasing electrical energy demand, slow expansion of transmission infrastructures, and electric energy market deregulation, are forcing utilities and system operators to operate power systems closer to their design limits. Operating under stressed regimes can have a detrimental effect on the rotor-angle stability of the system. This stability reduction is often reflected by the emergence or worsening of poorly damped low-frequency electromechanical oscillations. Without appropriate measures these can lead to costly blackouts. To guarantee system security, operators are sometimes forced to limit power transfers that are economically beneficial but that can result in poorly damped oscillations. Controllers that damp these oscillations can improve system reliability by preventing blackouts and provide long term economic gains by enabling more extensive utilization of the transmission infrastructure. Previous research in the use of artificial neural network-based intelligent controllers for power system damping control has shown promise when tested in small power system models. However, these controllers do not scale-up well enough to be deployed in realistically-sized power systems. The work in this dissertation focuses on improving the scalability of intelligent power system stabilizing controls so that they can significantly improve the rotor-angle stability of large-scale power systems. A framework for designing effective and robust intelligent controllers capable of scaling-up to large scale power systems is proposed. Extensive simulation results on a large-scale power system simulation model demonstrate the rotor-angle stability improvements attained by controllers designed using this framework.

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Bautista, Julian Ernesto. "Baryon acoustic oscillations in the large scale structures of the universe as seen by the Sloan Digital Sky Survey". Paris 7, 2014. http://www.theses.fr/2014PA077132.

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Ce manuscrit décrit la mesure des oscillations acoustiques des baryons (BAO) en utilisant des forêts Lyman-alpha et des galaxies, et son interprétation cosmologique. Entre 2011 et 2014, le télescope du Sloan Digital Sky Survey III a observé le spectre de plus de 1,3 millions de galaxies et plus de 150 000 quasars lointains dans le cadre du projet Baryon Oscillation Spectroscopic Survey (BOSS), en visant la mesure la plus précise des BAO dans la distribution de matière à grande échelle. Nous décrivons l'analyse des donnés, l'interprétation cosmologique et des tests avec des données simulées. Nous présentons une nouvelle méthode pour générer des données simulées, utilisées pour étudier des effets systématiques qui pourraient affecter la mesure. Aucun de ces effets ne change significativement nos résultats. Avec les données disponibles en 2014, le pic BAO est mesuré avec une précision de 3% dans la direction radiale et 5% dans la direction transverse à = 2,34. Nous comparons nos résultats avec des mesures précédentes, en particulier celles du satellite Planck, et nous trouvons un accord au niveau de 1,8ơ
This thesis describes the measurement of the baryon acoustic oscillations using Lyman-alpha forests and galaxies and its cosmological interprétation. From 2011 to 2014, the Sloan Digital Sky Survey III telescope observed spectra of — 1. 3 million galaxies and ∽ 150 000 quasars in the context of the Baryon Oscillation Spectroscopic Survey (BOSS). This project aimed the most accurate BAO measurement in the large scale distribution of matter. We describe the data analysis, the cosmological interprétation and tests using mock data. We present a new method to generate mock data, that was used to study systematic effects potentially affecting our measurement. No evidence for a systematic bias comming from these tests could be found. Using data available in 2014, the BAO peak is measured at 3% precision in the radial direction and 5% in the transverse direction, at z = 2. 34. We compare our results with previous measurements, in particular those from the Planck satellite, and we find an agreement at 1. 8ơ level

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Ding, Zhejie. "Systematics Study and Detection of Baryon Acoustic Oscillations from Future Galaxy Survey and Weak Lensing Survey". Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1554330484538948.

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Arico, Giovanni. "Testing the methods to reconstruct and model the Baryonic Acoustic Oscillations of different tracers using N-body simulations". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13167/.

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The accelerated expansion of the Universe and the nature of the Dark Energy are still open questions in cosmology. One of the most powerful ways to investigate these issues is to map the large-scale structure of the Universe, to constrain its expansion history and growth of structures. In particular, baryon acoustic oscillations (BAO) occurred at recombination make a peak in the correlation function of galaxies at the characteristic scale of the sound horizon (a sufficiently large scale to “protect” the signal from strong non-linearities), or alternatively a series of oscillations in the power spectrum. Since the sound horizon can be estimated with a great precision from the position of the first peak in the angular power spectrum of the Cosmic Microwave Background (which has the same physical origin of BAO, oscillations of the baryons-photons plasma), the BAO peak in the correlation function can be used as a standard ruler, providing paramount cosmological information. The aim of this thesis is to systematically test and possibly improve the state-of- the-art statistical methods to model the BAO peak, taking into account the non-linear evolution of matter overdensities, redshift-space distortions and the bias of cosmic tracers. To do that, we analyse mock samples of galaxies, quasars and galaxy clusters extracted from one of the largest available cosmological hydrodynamical simulations. We extract cosmological constraints from the BAO peak through different statistical tools in the redshift range 0.2 < z < 2. Although the BAO peak is at large scales, non-linear growth and galaxy peculiar velocities make the BAO signal smoothed and broader with respect to linear predictions, especially at low redshifts. A possible method to overcome these issues is the so-called reconstruction of the density field: one of the primary goals of this work is to implement a reconstruction method, to check its performances as a function of sample selections and redshift.

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Disotell, Kevin James. "Low-Frequency Flow Oscillations on Stalled Wings Exhibiting Cellular Separation Topology". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449162356.

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Pockberger, Moritz [Verfasser]. "Abiotic and biotic impacts on fish in the Wadden Sea - evaluating the effect of large scale climate oscillations, local ecosystem characteristics and invasive species / Moritz Pockberger". Kiel : Universitätsbibliothek Kiel, 2016. http://d-nb.info/1094661953/34.

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Książki na temat "Large scale oscillations"

Symposium, International Astronomical Union. New eyes to see inside the sun and stars: Pushing the limits of helio- and asteroseismology with new observations from the ground and from space : proceedings of the 185th Symposium of the International Astronomical Union, held in Kyoto, Japan, August 18-22, 1997. Dordrecht: Kluwer, 1998.

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F, Groeneweg John, i United States. National Aeronautics and Space Administration., red. Unsteady blade-surface pressures on a large-scale advanced propeller: Prediction and data. [Washington, DC]: National Aeronautics and Space Administration, 1990.

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Thalamocortical Assemblies: How Ion Channels, Single Neurons and Large-Scale Networks Organize Sleep Oscillations. Oxford University Press, USA, 2001.

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Unsteady blade-surface pressures on a large-scale advanced propeller: Prediction and data. [Washington, DC]: National Aeronautics and Space Administration, 1990.

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Unsteady blade-surface pressures on a large-scale advanced propeller: Prediction and data. [Washington, DC]: National Aeronautics and Space Administration, 1990.

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Lopes da Silva, Fernando H., i Eric Halgren. Neurocognitive Processes. Redaktorzy Donald L. Schomer i Fernando H. Lopes da Silva. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190228484.003.0048.

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Transmembrane neuronal currents that embody cognition in the cortex produce magnetoencephalographic and electroencephalographic signals. Frequency-domain analysis reveals standard rhythms with consistent topography, frequency, and cognitive correlates. Time-domain analysis reveals average event-related potentials and field (ERP/ERF) components with consistent topography, latency, and cognitive correlates. Standard rhythms and ERP/ERF components underlie perceiving stimuli; evaluating whether stimuli match predictions, and taking appropriate action when they do not; encoding stimuli to permit semantic processing and then accessing lexical representations and assigning syntactic roles; maintaining information in primary memory; preparing to take an action; and closing processing of an event–response sequence. Sustained mental processes are associated with theta and gamma. Consolidating memories appears to occur mainly during replay of specific firing patterns during sleep spindles and slow oscillations. Biophysical, neuroanatomical, and neurophysiological factors interact to render cognitive rhythms and components particularly sensitive to the large-scale modulatory processes that sequence and integrate higher cortical processing.

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Busuioc, Aristita, i Alexandru Dumitrescu. Empirical-Statistical Downscaling: Nonlinear Statistical Downscaling. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.770.

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This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Climate Science. Please check back later for the full article.The concept of statistical downscaling or empirical-statistical downscaling became a distinct and important scientific approach in climate science in recent decades, when the climate change issue and assessment of climate change impact on various social and natural systems have become international challenges. Global climate models are the best tools for estimating future climate conditions. Even if improvements can be made in state-of-the art global climate models, in terms of spatial resolution and their performance in simulation of climate characteristics, they are still skillful only in reproducing large-scale feature of climate variability, such as global mean temperature or various circulation patterns (e.g., the North Atlantic Oscillation). However, these models are not able to provide reliable information on local climate characteristics (mean temperature, total precipitation), especially on extreme weather and climate events. The main reason for this failure is the influence of local geographical features on the local climate, as well as other factors related to surrounding large-scale conditions, the influence of which cannot be correctly taken into consideration by the current dynamical global models.Impact models, such as hydrological and crop models, need high resolution information on various climate parameters on the scale of a river basin or a farm, scales that are not available from the usual global climate models. Downscaling techniques produce regional climate information on finer scale, from global climate change scenarios, based on the assumption that there is a systematic link between the large-scale and local climate. Two types of downscaling approaches are known: a) dynamical downscaling is based on regional climate models nested in a global climate model; and b) statistical downscaling is based on developing statistical relationships between large-scale atmospheric variables (predictors), available from global climate models, and observed local-scale variables of interest (predictands).Various types of empirical-statistical downscaling approaches can be placed approximately in linear and nonlinear groupings. The empirical-statistical downscaling techniques focus more on details related to the nonlinear models—their validation, strengths, and weaknesses—in comparison to linear models or the mixed models combining the linear and nonlinear approaches. Stochastic models can be applied to daily and sub-daily precipitation in Romania, with a comparison to dynamical downscaling. Conditional stochastic models are generally specific for daily or sub-daily precipitation as predictand.A complex validation of the nonlinear statistical downscaling models, selection of the large-scale predictors, model ability to reproduce historical trends, extreme events, and the uncertainty related to future downscaled changes are important issues. A better estimation of the uncertainty related to downscaled climate change projections can be achieved by using ensembles of more global climate models as drivers, including their ability to simulate the input in downscaling models. Comparison between future statistical downscaled climate signals and those derived from dynamical downscaling driven by the same global model, including a complex validation of the regional climate models, gives a measure of the reliability of downscaled regional climate changes.

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Rosenzweig, Cynthia, i Daniel Hillel. Climate Variability and the Global Harvest. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195137637.001.0001.

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The Earth's climate is constantly changing. Some of the changes are progressive, while others fluctuate at various time scales. The El Niño-la Niña cycle is one such fluctuation that recurs every few years and has far-reaching impacts. It generally appears at least once per decade, but this may vary with our changing climate. The exact frequency, sequence, duration and intensity of El Niño's manifestations, as well as its effects and geographic distributions, are highly variable. The El Niño-la Niña cycle is particularly challenging to study due to its many interlinked phenomena that occur in various locations around the globe. These worldwide teleconnections are precisely what makes studying El Niño-la Niña so important. Cynthia Rosenzweig and Daniel Hillel describe the current efforts to develop and apply a global-to-regional approach to climate-risk management. They explain how atmospheric and social scientists are cooperating with agricultural practitioners in various regions around the world to determine how farmers may benefit most from new climate predictions. Specifically, the emerging ability to predict the El Niño-Southern Oscillation (ENSO) cycle offers the potential to transform agricultural planning worldwide. Biophysical scientists are only now beginning to recognize the large-scale, globally distributed impacts of ENSO on the probabilities of seasonal precipitation and temperature regimes. Meanwhile, social scientists have been researching how to disseminate forecasts more effectively within rural communities. Consequently, as the quality of climatic predictions have improved, the dissemination and presentation of forecasts have become more effective as well. This book explores the growing understanding of the interconnectedness of climate predictions and productive agriculture for sustainable development, as well as methods and models used to study this relationship.

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Kucharski, Fred, i Muhammad Adnan Abid. Interannual Variability of the Indian Monsoon and Its Link to ENSO. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.615.

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The interannual variability of Indian summer monsoon is probably one of the most intensively studied phenomena in the research area of climate variability. This is because even relatively small variations of about 10% to 20% from the mean rainfall may have dramatic consequences for regional agricultural production. Forecasting such variations months in advance could help agricultural planning substantially. Unfortunately, a perfect forecast of Indian monsoon variations, like any other regional climate variations, is impossible in a long-term prediction (that is, more than 2 weeks or so in advance). The reason is that part of the atmospheric variations influencing the monsoon have an inherent predictability limit of about 2 weeks. Therefore, such predictions will always be probabilistic, and only likelihoods of droughts, excessive rains, or normal conditions may be provided. However, even such probabilistic information may still be useful for agricultural planning. In research regarding interannual Indian monsoon rainfall variations, the main focus is therefore to identify the remaining predictable component and to estimate what fraction of the total variation this component accounts for. It turns out that slowly varying (with respect to atmospheric intrinsic variability) sea-surface temperatures (SSTs) provide the dominant part of the predictable component of Indian monsoon variability. Of the predictable part arising from SSTs, it is the El Niño Southern Oscillation (ENSO) that provides the main part. This is not to say that other forcings may be neglected. Other forcings that have been identified are, for example, SST patterns in the Indian Ocean, Atlantic Ocean, and parts of the Pacific Ocean different from the traditional ENSO region, and springtime snow depth in the Himalayas, as well as aerosols. These other forcings may interact constructively or destructively with the ENSO impact and thus enhance or reduce the ENSO-induced predictable signal. This may result in decade-long changes in the connection between ENSO and the Indian monsoon. The physical mechanism for the connection between ENSO and the Indian monsoon may be understood as large-scale adjustment of atmospheric heatings and circulations to the ENSO-induced SST variations. These adjustments modify the Walker circulation and connect the rising/sinking motion in the central-eastern Pacific during a warm/cold ENSO event with sinking/rising motion in the Indian region, leading to reduced/increased rainfall.

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Nash, David. Changes in Precipitation Over Southern Africa During Recent Centuries. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.539.

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Precipitation levels in southern Africa exhibit a marked east–west gradient and are characterized by strong seasonality and high interannual variability. Much of the mainland south of 15°S exhibits a semiarid to dry subhumid climate. More than 66 percent of rainfall in the extreme southwest of the subcontinent occurs between April and September. Rainfall in this region—termed the winter rainfall zone (WRZ)—is most commonly associated with the passage of midlatitude frontal systems embedded in the austral westerlies. In contrast, more than 66 percent of mean annual precipitation over much of the remainder of the subcontinent falls between October and March. Climates in this summer rainfall zone (SRZ) are dictated by the seasonal interplay between subtropical high-pressure systems and the migration of easterly flows associated with the Intertropical Convergence Zone. Fluctuations in both SRZ and WRZ rainfall are linked to the variability of sea-surface temperatures in the oceans surrounding southern Africa and are modulated by the interplay of large-scale modes of climate variability, including the El Niño-Southern Oscillation (ENSO), Southern Indian Ocean Dipole, and Southern Annular Mode.Ideas about long-term rainfall variability in southern Africa have shifted over time. During the early to mid-19th century, the prevailing narrative was that the climate was progressively desiccating. By the late 19th to early 20th century, when gauged precipitation data became more readily available, debate shifted toward the identification of cyclical rainfall variation. The integration of gauge data, evidence from historical documents, and information from natural proxies such as tree rings during the late 20th and early 21st centuries, has allowed the nature of precipitation variability since ~1800 to be more fully explored.Drought episodes affecting large areas of the SRZ occurred during the first decade of the 19th century, in the early and late 1820s, late 1850s–mid-1860s, mid-late 1870s, earlymid-1880s, and mid-late 1890s. Of these episodes, the drought during the early 1860s was the most severe of the 19th century, with those of the 1820s and 1890s the most protracted. Many of these droughts correspond with more extreme ENSO warm phases.Widespread wetter conditions are less easily identified. The year 1816 appears to have been relatively wet across the Kalahari and other areas of south central Africa. Other wetter episodes were centered on the late 1830s–early 1840s, 1855, 1870, and 1890. In the WRZ, drier conditions occurred during the first decade of the 19th century, for much of the mid-late 1830s through to the mid-1840s, during the late 1850s and early 1860s, and in the early-mid-1880s and mid-late 1890s. As for the SRZ, markedly wetter years are less easily identified, although the periods around 1815, the early 1830s, mid-1840s, mid-late 1870s, and early 1890s saw enhanced rainfall. Reconstructed rainfall anomalies for the SRZ suggest that, on average, the region was significantly wetter during the 19th century than the 20th and that there appears to have been a drying trend during the 20th century that has continued into the early 21st. In the WRZ, average annual rainfall levels appear to have been relatively consistent between the 19th and 20th centuries, although rainfall variability increased during the 20th century compared to the 19th.

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Części książek na temat "Large scale oscillations"

Dong, Xinzhou. "Immunityin Distance Protection of Oscillations". W AC/DC Hybrid Large-Scale Power Grid System Protection, 109–40. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-6486-2_3.

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Westhoff, A., D. Schmeling, J. Bosbach i C. Wagner. "Oscillations of Large-Scale Structures in turbulent Mixed Convection in a rectangular enclosure". W Springer Proceedings in Physics, 533–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03085-7_128.

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Hashemiyoon, Rowshanak, i John K. Chapin. "Spatiotemporal Patterns of Light Stimulation are Correlated with Large Scale Dynamical Patterns of Synchronised Oscillations". W Computational Neuroscience, 677–81. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4757-9800-5_105.

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Tosunoglu, Fatih, Ercan Kahya i Mohammad Ali Ghorbani. "Spatial and Temporal Linkages between Large-Scale Atmospheric Oscillations and Hydrologic Drought Indices in Turkey". W Integrated Drought Management, Volume 2, 1–16. Boca Raton: CRC Press, 2023. http://dx.doi.org/10.1201/9781003276548-1.

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Siebenhühner, Felix, Muriel Lobier, Sheng H. Wang, Satu Palva i J. Matias Palva. "Measuring Large-Scale Synchronization with Human MEG and EEG: Challenges and Solutions". W Multimodal Oscillation-based Connectivity Theory, 1–18. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-32265-0_1.

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Palva, Satu, i J. Matias Palva. "The Role of Local and Large-Scale Neuronal Synchronization in Human Cognition". W Multimodal Oscillation-based Connectivity Theory, 51–67. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-32265-0_4.

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McCreary, Julian P. "Coupled Ocean-Atmosphere Models of El Nino and the Southern Oscillation". W Large-Scale Transport Processes in Oceans and Atmosphere, 247–80. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4768-9_7.

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Shi, Wuzhi, Ke Zhang, Yuebo Xie, Lijun Chao, Tolossa Lemma Tola i Xianwu Xue. "Monitoring the Variation of Drought-Flood Abrupt Alternation and Its Response to Atmospheric Circulation at Multi-time Scales". W Lecture Notes in Civil Engineering, 1139–51. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_100.

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AbstractAs an emerging disaster, the drought-flood abrupt alternation (DFAA) may cause unprecedented socio-economic impacts under changing environment, which has attracted extensive attention in recent decades. DFAA involves drought to flood (DTF) and flood to drought (FTD). However, thus far, little effort has been made to identify DFAA with high spatial resolution. Moreover, few studies have fully revealed the driving mechanisms of DFAA by large-scale climate factors. Here, the Yellow River Basin (YRB) was selected as the research area, which is an important agricultural base in China. The spatiotemporal characteristics of DFAA at multiple time scales during flood season were analyzed using 0.25° grid precipitation from 1961 to 2020 in the YRB. Furthermore, the Pearson correlation method and cross wavelet method were used to investigate the relationship between circulation anomaly (such as Arctic oscillation (AO), Pacific decadal oscillation (PDO), El Niño Southern Oscillation (ENSO), and sunspot) and DFAA to explore the potential causes of DFAA in this region. The results demonstrated that: (1) FTD trend in the YRB is serious, and the short period of FTD trend is June-July > July-August > August-September; (2) spatially, the high-frequency long-period DFAA was distributed in the whole YRB, while the DFAA in June-July and July-August were concentrated in the center of the YRB; (3) AO and PDO are the key factors to induce DFAA in the YRB, especially the changes of AO and PDO phase. This study helps improve our understanding of the relationship between DFAA and large-scale climate factors and provides new insights for future disaster assessment.

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Wang, Yaozong, Xiaorong Hu, Sun Zhou i Guoli Ji. "Oscillation Source Detection for Large-Scale Chemical Process with Interpretative Structural Model". W Advances in Intelligent Systems and Computing, 441–51. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-38771-0_43.

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Fujisawa, Shigeyoshi. "Slow Oscillation in Prefrontal Cortex Underlying Local Computations and Large-Scale Interactions". W The Physics of the Mind and Brain Disorders, 233–45. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-29674-6_11.

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Streszczenia konferencji na temat "Large scale oscillations"

Glumov, Victor. "Prediction and Stabilization of Elastic Oscillations of a Large Space Construction". W 2021 14th International Conference Management of large-scale system development (MLSD). IEEE, 2021. http://dx.doi.org/10.1109/mlsd52249.2021.9600104.

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Díaz, Diana, Diana Díaz, Nancy Villegas i Nancy Villegas. "CANONICAL CORRELATION AMONG LARGE SCALE OSCILLATIONS, TEMPERATURE AND PRECIPITATION IN COASTAL REGIONS OF COLOMBIA". W Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b93a05a4f25.66586448.

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This study examines relationships between available surface meteorology variables and climatic oscillations by using canonical correlation analysis (CCA). Canonical loadings and cross loadings from CCA are evaluated for meteorological stations located over coastal regions of Colombia. The tests, used for these studies, consider the temperature, the precipitation data, three of the main oscillations – the Ocean Niño Index (ONI), North Atlantic Oscillation (NAO), and the Quasi-biennial oscillation (QBO). The results show the power of the statistical method used to identify associations on the data set with an acceptable level of confidence using multivariate approach. The analysis reveals relations mostly between the variables and the ENSO for all cases and a discrete connection with the NAO and QBO. To add climate indices to the group of independent variables increased the variance rates between 5 and 7%.

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Biroon, Roghieh A., Pierluigi Pisu i David Schoenwald. "Inter-Area Oscillation Damping in Large-Scale Power Systems Using Decentralized Control". W ASME 2018 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/dscc2018-9119.

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Inter-area oscillation is one of the main concerns in power system small signal stability. It involves wide area in power system, therefore identifying the causes and damping these oscillations are challenging. Undamped inter-area oscillations may cause severe problems in power systems including large-scale blackouts. Designing a proper controller for power systems also is a challenging problem due to the complexity of the system. Moreover, for a large-scale system it is impractical to collect all system information in one location to design a centralized controller. Decentralized controller will be more desirable for large scale systems to minimize the inter area oscillations by using local information. In this paper, we consider a large-scale power system consisting of three areas. After decomposing the system into three subsystems, each subsystem is modeled with a lower order system. Finally, a decentralized controller is designed for each subsystem to maintain the large-scale system frequency at the desired level even in the presence of disturbances.

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Yari, Siavash, i Masoud Khatibi. "Damping Improvement of Inter-Area Oscillations Using Large-Scale Wind Farms". W 2021 7th Iran Wind Energy Conference (IWEC). IEEE, 2021. http://dx.doi.org/10.1109/iwec52400.2021.9467027.

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Wang, D., M. Glavic i L. Wehenkel. "Distributed MPC of wide-area electromechanical oscillations of large-scale power systems". W 2011 16th International Conference on Intelligent System Applications to Power Systems (ISAP). IEEE, 2011. http://dx.doi.org/10.1109/isap.2011.6082163.

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Xiangyi, Chen, Li Chunyan i Wang Yunli. "Analysis of the inter-area low frequency oscillations in large scale power systems". W 2011 6th IEEE Conference on Industrial Electronics and Applications (ICIEA). IEEE, 2011. http://dx.doi.org/10.1109/iciea.2011.5975851.

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Padilla, Rodrigo, Vibhav Durgesh i Tao Xing. "Application of Proper Orthogonal Decomposition to Study the Flow Over an Oscillating Flag". W ASME 2022 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/fedsm2022-86969.

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Abstract Fluid-Structure-Interaction (FSI) is the coupling between a flowing fluid and a structure that results in either a static or dynamic structure deformation. This investigation focused on applying Proper Orthogonal Decomposition (POD) to study the fluid flow behavior of an oscillating flag and using POD modes to quantify the changes in flow behavior associated with the change in flag oscillation modes. For this purpose, aerodynamic load, membrane location, and Particle Image Velocimetry (PIV) measurements were performed for a selected flag model. The flag location measurements helped identify the change in oscillation shapes and modes with change in flow conditions, while the aerodynamic load data allowed us to quantify the impact of flag oscillations on the aerodynamic load experienced by the flag. The PIV data provide flow field information around the oscillating flag and were used to perform POD analysis. We observed that the POD mode, energy, and time-varying coefficients changed with change in the oscillation modes of the flag (i.e., change from mode-2 to mode-3 oscillations). Flow reconstruction using the first three POD modes allowed us to capture changes generated in large-scale structures in the flow due to changes in the oscillation modes. Flow reconstruction using the remaining POD modes allowed us to observe the behavior of small-scale flow structures and K-H vortices in the wake of the flag. The POD approach used here allowed us to quantify the change in flow behavior and understand the underlying FSI mechanism therein.

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Castellanos, B. R., A. R. Messina, G. J. G. Calderon i U. H. Sarmiento. "Large-scale Use of FACTS Technology for Damping Inter-Area Oscillations in the Mexican System". W 2007 IEEE Power Engineering Society General Meeting. IEEE, 2007. http://dx.doi.org/10.1109/pes.2007.386125.

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Gu, Xiaochun, Xia Peng, Fang Han i Zhijie Wang. "Regeneration of Gamma Oscillations in Large-scale Neural Network with Complicated Structure Based on CUDA". W SPML 2020: 2020 3rd International Conference on Signal Processing and Machine Learning. New York, NY, USA: ACM, 2020. http://dx.doi.org/10.1145/3432291.3432304.

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Raporty organizacyjne na temat "Large scale oscillations"

Deaton i Frost. L51571 Pipe-Soil Interaction Tests on Sand and Soft Clay. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), październik 1987. http://dx.doi.org/10.55274/r0010291.

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This project was performed to establish a basis for developing pipe-soil interaction models suitable for PRCI's pipeline design program: "PIPEDYN". Full-scale pipe-soil tests on loose and dense sand and soft clay were performed at the Norwegian Hydrotechnical Laboratory, affiliated with SINTEF. The program tested soil resistance to lateral motions of full-scale (0.5 m and 1.0 m OD) pipe sections on loose and dense sand and soft clay. A test rig was used with a soil flume 12.5 m long, 1.8 m wide, and 0.6 m high, and containing 13.5 m3 of sand or soft clay. Three control signals were applied to the test pipes: simple breakout, regular oscillatory tests and breakout, and random tests with force time histories. The parameters considered were pipe diameter, pipe weight, pipe oscillations, and oscillation amplitude. A total of 110 tests were performed in 25 test flumes (13 preliminary and 12 main) on loose sand, three test flumes on dense sand and ten test flumes on soft clay. Forty-five preliminary and 32 main tests were performed in 25 loose sand flume preparations, whereas 8 main tests were performed in 3 dense sand flumes and 25 main tests in 10 soft clay flumes, for a grand total of 110 pipe-soil tests in 38 soil flumes. Special plate and cone penetration tests were also performed as part of the soil bed tests. Based on the results of the tests, pipe penetration appears to be the most important factor influencing lateral soil resistance. Also, the soil resistance in loose sand was generally higher than in dense sand due to larger pipe penetration and an accordingly higher lateral earth pressure.

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