Browsing by Author "Baxevani, Anastassia"

Now showing items 1-20 of 24

    • Article  

      Dynamically evolving Gaussian spatial fields 

      Baxevani, Anastassia; Podgórski, K.; Rychlik, I. (2011)
      We discuss general non-stationary spatio-temporal 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 Palmgren-Miner additive rule and the rainflow ...
    • Conference Object  

      How fast are the two-dimensional gaussian waves? 

      Baxevani, Anastassia; Podgórski, K.; Rychlik, I. (2002)
      For a stationary two-dimensional 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 up-crossings, for spatio-temporal 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 non-gaussian 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 self-similar 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 non-Gaussian 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  

      Space-time 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, $H-s$, 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  

      Spatio-temporal statistical modelling of significant wave height 

      Baxevani, Anastassia; Caires, Sofia; Rychlik, I. (2009)
      In this paper, we construct a homogeneous spatio-temporal 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 ...