Browsing by Author "Baxevani, Anastassia"
Now showing items 120 of 24

Article
Dynamically evolving Gaussian spatial fields
Baxevani, Anastassia; Podgórski, K.; Rychlik, I. (2011)We discuss general nonstationary spatiotemporal surfaces that involve dynamics governed by velocity fields. The approach formalizes and expands previously used models in analysis of satellite data of significant wave ...

Article
Fatigue life prediction for a vessel sailing the North Atlantic route
Baxevani, Anastassia; Rychlik, I. (2007)A method for calculating the wave load induced fatigue damage accumulated by a vessel sailing along the North Atlantic route (NAr) is presented. This method is based on the PalmgrenMiner additive rule and the rainflow ...

Conference Object
How fast are the twodimensional gaussian waves?
Baxevani, Anastassia; Podgórski, K.; Rychlik, I. (2002)For a stationary twodimensional random field evolving in time, we derive the intensity distributions of appropriately defined velocities of crossing contours. The results are based on a generalization of the Rice formula. ...

Article
Maxima for Gaussian seas
Baxevani, Anastassia; Rychlik, I. (2006)The probability distribution of the height of global maximum for a Gaussian random field evolving in time is studied. In particular, the effect of spreading is studied and the role of the wave kinematics is discussed. It ...

Article
Modelling precipitation in Sweden using multiple step markov chains and a composite model
Lennartsson, J.; Baxevani, Anastassia; Chen, D. (2008)In this paper, we propose a new method for modelling precipitation in Sweden. We consider a chain dependent stochastic model that consists of a component that models the probability of occurrence of precipitation at a ...

Book
Modelling sea surface dynamics using crossing distributions
Baxevani, Anastassia (Univ., Centre for Mathematical Sciences, Mathematical StatisticsUniv., Centre for Mathematical Sciences, Mathematical Statistics, 2004)

Conference Object
Modelling significant wave height in the North Atlantic
Baxevani, Anastassia; Rychlik, I.; Wilson, R. J. (2003)The surface of the ocean, and so such quantities as the significant wave height, can be thought of as a random surface in space which develops over time. In this paper, we explore certain types of random fields (in space ...

Article
A new method for modelling the space variability of significant wave height
Baxevani, Anastassia; Rychlik, I.; Wilson, R. J. (2005)Significant wave height, Hs, is a measure of the variability of the ocean surface and is defined to be four times the standard deviation of the height of the ocean surface. In this paper, we present a methodology for ...

Conference Object
Note on the distribution of extreme wave crests
Baxevani, Anastassia; Hagberg, O.; Rychlik, I. (2005)The sea elevation at a fixed point is modelled by means of a second order model, which is a smooth algebraic function of a vector valued Gaussian process. Asymptotic methods, presented first in [1], are used to estimate ...

Article
Prediction of catastrophes in space over time
Baxevani, Anastassia; Wilson, Richard (2018)Predicting rare events, such as high level upcrossings, for spatiotemporal processes plays an important role in the analysis of the occurrence and impact of potential catastrophes in, for example, environmental settings. ...

Article
Random spectral measure for non Gaussian moving averages
Baxevani, Anastassia; Podgórski, K. (2017)We study the distribution of phases and amplitudes for the spectral representation of weighted moving averages of a general noise measure. The simple independent structure, known for the Gaussian case, and involving Rayleigh ...

Article
Random spectral measure for non Gaussian moving averages
Baxevani, Anastassia; Podgórski, Krzysztof (2018)We study the distribution of phases and amplitudes for the spectral representation of weighted moving averages of a general noise measure. The simple independent structure, known for the Gaussian case, and involving Rayleigh ...

Conference Object
Relation between velocities and global maximum for Gaussian seas
Baxevani, Anastassia; Rychlik, I. (2004)We study the probability distribution of the height of global maximum for a Gaussian random field evolving in time. Particularly, we discuss the role of the wave kinematics. It is observed that taking into account time ...

Article
Sample path asymmetries in nongaussian random processes
Baxevani, Anastassia; Podgórski, K.; Wegener, J. (2014)We tackle an important although rarely addressed question of accounting for a variety of asymmetries frequently observed in stochastic temporal/spatial records. First, we review some measures intending to capture such ...

Article
Series decomposition of fractional Brownian motion and its Lamperti transform
Baxevani, Anastassia; Podgórski, K. (2009)The Lamperti transformation of a selfsimilar process is a stationary process. In particular, the fractional Brownian motion transforms to the second order stationary Gaussian process. This process is represented as a ...

Article
Signals Featuring Harmonics with Random Frequencies  Spectral, Distributional and Ergodic Properties
Baxevani, Anastassia; Podgórski, Krzysztof (2019)It has been observed that an interesting class of nonGaussian stationary processes is obtained when in the harmonics of a signal with random amplitudes and phases, frequencies can also vary randomly. In the resulting ...

Article
Spacetime models for moving fields with an application to significant wave height fields
Ailliot, P.; Baxevani, Anastassia; Cuzol, A.; Monbet, V.; Raillard, N. (2011)The surface of the ocean, and so such quantities as the significant wave height, $Hs$, can be thought of as a random surface that develops over time. In this paper, we explore certain types of random fields in space and ...

Conference Object
Spatial models for the variability of the significant wave height on the world oceans
Baxevani, Anastassia; Borgel, C.; Rychlik, I. (2007)Significant wave height (Hs) is a measure of the variability of the ocean surface. Knowledge of the spatial and temporal characteristics of this field are multiple: it is useful to dimension offshore structures, to foresee ...

Article
Spatial models for variability of significant wave height in world oceans
Baxevani, Anastassia; Borgel, C.; Rychlik, I. (2008)Significant wave height (Hs) is a measure of the variability of the ocean surface. Benefits from knowing the spatial and temporal characteristics of this field are multiple: It is useful to size offshore structures, to ...

Article
Spatiotemporal statistical modelling of significant wave height
Baxevani, Anastassia; Caires, Sofia; Rychlik, I. (2009)In this paper, we construct a homogeneous spatiotemporal model to describe the variability of significant wave height over small regions of the sea and over short periods of time. Then, the model is extended to a ...