Search results for "PROBABILITY"
showing 10 items of 3417 documents
In search for a canonical design ABL stability class for wind farm turbines
2016
Production as well as loading of wake exposed wind turbines is known to depend significantly on stability of the Atmospheric Boundary Layer (ABL), which adds a new dimension to design of wind farm turbines. Adding this new aspect in wind turbine design makes the number of design cycle computations to blow up with a factor equal to the number of representative stability bin classes. The research question to be answered in this paper is: Can an ABL stability probability distribution in a meaningful way be collapsed into a representative design stability class as based on a (predefined) confidence level.
Basics of doubly heavy tetraquarks
2018
We outline the most important results regarding the stability of doubly heavy tetraquarks $QQ\bar q\bar q$ with an adequate treatment of the four-body dynamics. We consider both color-mixing and spin-dependent effects. Our results are straightforwardly applied to the case of all-heavy tetraquarks $QQ\bar Q\bar Q$. We conclude that the stability is favored in the limit $M_Q/m_q \gg 1$ pointing to the stability of the $bb\bar u\bar d$ state and the instability of all-heavy tetraquarks.
Post-Double Hopf Bifurcation Dynamics and Adaptive Synchronization of a Hyperchaotic System
2012
In this paper a four-dimensional hyperchaotic system with only one equilibrium is considered and its double Hopf bifurcations are investigated. The general post-bifurcation and stability analysis are carried out using the normal form of the system obtained via the method of multiple scales. The dynamics of the orbits predicted through the normal form comprises possible regimes of periodic solutions, two-period tori, and three-period tori in parameter space. Moreover, we show how the hyperchaotic synchronization of this system can be realized via an adaptive control scheme. Numerical simulations are included to show the effectiveness of the designed control.
A MCDM-based methodology to evaluate the mutual influence among performance shaping factors
2022
In recent decades, risk analysts have widely focused on Human Reliability Analysis (HRA) methods to assess the contribution of human errors to system failures, also considering contextual and cognitive factors named Performance Shaping Factors (PSFs). Initially implemented in the field of Nuclear Power Plants (NNPs), HRA methods have been extended to different sectors in recent years. Despite that, the majority of contributions in the field assume the independence among PSFs, which may result in an over or under estimation of the Human Error Probability (HEP). Therefore, the present paper proposes a DEMATEL-based approach to evaluate the mutual influence between PSFs proposed by the SPARH m…
Applying a probabilistic model of rainfall and snow days occurrence to daily series recorded in NW Italy.
2014
Daily precipitation records exist spanning several decades. A valuable amount of climatic information exists in the time-series of interarrival times (IT), defined as the succession of times (number of days) elapsed from a rainy (or snowy) day to the one immediately preceding it.In a previous work, Agnese et al. (2014) have been successfully tested some probabilistic modelling of rain occurrence on Sicily rainfall data; particularly, the better fitting of IT’s observed frequencies was obtained by 3-parameter Lerch-series distribution. In this work thisdistribution is tested on 70 years of 20 precipitation time-series taken in the North-West Italy, both in the plain and in the mountains, up …
A Wiener Path Integral Technique for Non-Stationary Response Determination of Nonlinear Oscillators with Fractional Derivative Elements
2014
In this paper a novel approximate analytical technique for determining the non-stationary response probability density function (PDF) of randomly excited linear and nonlinear oscillators with fractional derivative elements is developed. Specifically, the concept of the Wiener path integral in conjunction with a variational formulation is utilized to derive an approximate closed form solution for the system response non-stationary PDF. Notably, the determination of the non-stationary response PDF is accomplished without the need to advance the solution in short time steps as it is required by the existing alternative numerical path integral solution schemes. In this manner, the analytical Wi…
Sequential Monte Carlo Methods in Random Intercept Models for Longitudinal Data
2017
Longitudinal modelling is common in the field of Biostatistical research. In some studies, it becomes mandatory to update posterior distributions based on new data in order to perform inferential process on-line. In such situations, the use of posterior distribution as the prior distribution in the new application of the Bayes’ theorem is sensible. However, the analytic form of the posterior distribution is not always available and we only have an approximated sample of it, thus making the process “not-so-easy”. Equivalent inferences could be obtained through a Bayesian inferential process based on the set that integrates the old and new data. Nevertheless, this is not always a real alterna…
Parameter Uncertainty in Shallow Rainfall-triggered Landslide Modeling at Basin Scale: A Probabilistic Approach
2014
Abstract This study proposes a methodology to account for the uncertainty of hydrological and mechanical parameters in coupled distributed hydrological-stability models for shallow landslide assessment. A probabilistic approach was implemented in an existing eco-hydrological and landslide model by randomizing soil cohesion, friction angle and soil retention parameters. The model estimates the probability of failure through an assumed theoretical Factor of Safety (FS) distribution, conditioned on soil moisture content. The time-dependent and spatially distributed FS statistics are approximated by the First Order Second Moment (FOSM) method. The model was applied to the Rio Mameyes Basin, loc…
Probability Distribution of Peak Discharge at the Hillslope Scale Generated by Hortonian Runoff
2016
In this work, the probability distribution of peak discharge at the hillslope bottom is determined hypothesizing a prevalent Hortonian mechanism of runoff production for a given rainfall duration. As is well known, the probability distribution of peak discharge depends on the probability of both the rainfall event as well as that of the antecedent soil moisture conditions. In particular, the probability of the rainfall event is calculated according to the familiar rainfall duration-intensity-frequency approach, whereas the ecohydrological method from the literature is used here to define the probability of the antecedent soil moisture conditions. The latter depends on a set of parameters de…
Modeling the probability distribution of peak discharge for infiltrating hillslopes
2017
Hillslope response plays a fundamental role in the prediction of peak discharge at the basin outlet. The peak discharge for the critical duration of rainfall and its probability distribution are needed for designing urban infrastructure facilities. This study derives the probability distribution, denoted as GABS model, by coupling three models: (1) the Green-Ampt model for computing infiltration, (2) the kinematic wave model for computing discharge hydrograph from the hillslope, and (3) the intensity-duration-frequency (IDF) model for computing design rainfall intensity. The Hortonian mechanism for runoff generation is employed for computing the surface runoff hydrograph. Since the antecede…