Search results for "Simulation."
showing 10 items of 4779 documents
Knowledge-driven multi-agent simulation engineering for assessing the effectiveness of disaster management plans
2020
Protecting humans from disasters has been an active mission of governments and experts through the definition of disaster management plans. Defining disaster response strategies is crucial in order to reduce the number of victims and the economic impact. In order to select which response plan is best suited to a specific disaster situation, these plans must be evaluated. However, such evaluation is limited by the high cost of exercises and the specificity of existing simulation models. The approach defended in this thesis combines techniques from Semantic Web and multi-agent simulation to evaluate disaster management response plans. It is composed of four steps : (1) modeling disaster manag…
Invariant rotational curves in Sitnikov's Problem
1993
The Sitnikov's Problem is a Restricted Three-Body Problem of Celestial Mechanics depending on a parameter, the eccentricity,e. The Hamiltonian,H(z, v, t, e), does not depend ont ife=0 and we have an integrable system; ife is small the KAM Theory proves the existence of invariant rotational curves, IRC. For larger eccentricities, we show that there exist two complementary sequences of intervals of values ofe that accumulate to the maximum admissible value of the eccentricity, 1, and such that, for one of the sequences IRC around a fixed point persist. Moreover, they shrink to the planez=0 ase tends to 1.
Large eddy simulation of inertial particles dispersion in a turbulent gas-particle channel flow bounded by rough walls
2020
The purpose of this paper is to understand the capability and consistency of large eddy simulation (LES) in Eulerian–Lagrangian studies aimed at predicting inertial particle dispersion in turbulent wall-bounded flows, in the absence of ad hoc closure models in the Lagrangian equations of particle motion. The degree of improvement granted by LES models is object of debate, in terms of both accurate prediction of particle accumulation and local particle segregation; therefore, we assessed the accuracy in the prediction of the particle velocity statistics by comparison against direct numerical simulation (DNS) of a finer computational mesh, under both one-way and two-way coupling regimes. We p…
Theoretical prediction of rainfall intensity for a small rainfall simulator
2022
In this contribution, a theoretical approach was developed for predicting rainfall intensity for a small rainfall simulator. The developed equation was tested for two different devices and different pressure head and water temperature values. The proposed relationship was found to have a good predictive ability of rainfall intensity. The proposed theoretical approach could be usable with other devices that operate on the same principles of the simulator considered in this investigation.
Modelling urban networks at mega-regional scale: Are increasingly complex urban systems sustainable?
2015
Are the dynamics of mega-regions sustainable or not? We explore the hypothesis that increasing complexity in mega-regions implies less demands on resources needed to generate organized information, thereby making the systems more efficient and stable. This article aims to identify structural indicators for measuring urban networks at the mega-regional scale. We use night-time light data from the broad band near-visible infrared channel of the DMSP-OLS to monitor the dynamics of urbanization. We study the urban networks as graphs, where nodes are cities, and the main road and railway infrastructures represent the edges. We propose four indicators for measuring the complexity, polycentricity,…
On mathematical modelling of the solid-liquid mixtures transport in porous axial-symmetrical container with Henry and Langmuir sorption kinetics
2018
In this paper we study diffusion and convection filtration problem of one substance through the pores of a porous material which may absorb and immobilize some of the diffusing substances. As an example we consider round cylinder with filtration process in the axial direction. The cylinder is filled with sorbent i.e. absorbent material that passed through dirty water or liquid solutions. We can derive the system of two partial differential equations (PDEs), one expressing the rate of change of concentration of water in the pores of the sorbent and the other - the rate of change of concentration in the sorbent or kinetical equation for absorption. The approximation of corresponding initial b…
From a bodily-based format of knowledge to symbols. The evolution of human language
2013
Although ontogeny cannot recapitulate phylogeny, a two-level model of the acquisition of language will be here proposed and its implication for the evolution of the faculty of language will be discussed. It is here proposed that the identification of the cognitive requirements of language during ontogeny could help us in the task of identifying the phylogenetic achievements that concurred, at some point, to the acquisition of language during phylogeny. In this model speaking will be considered as a complex ability that arises in two different steps. The first step of competence widely relies on a bodily-based format of knowledge. The second step relies on more abstract meta-representations …
Language Environment in University: Accessibility, Quality, Sustainability
2014
LU Valodu centra Starptautiskās konferences rakstu krājums
Laparoscopic assistance by operating room nurses: Results of a virtual-reality study
2016
Abstract Background Laparoscopic assistance is often entrusted to a less experienced resident, medical student, or operating room nurse. Data regarding laparoscopic training for operating room nurses are not available. Objectives The aim of the study was to analyse the initial performance level and learning curves of operating room nurses in basic laparoscopic surgery compared with medical students and surgical residents to determine their ability to assist with this type of procedure. Design The study was designed to compare the initial virtual reality performance level and learning curves of user groups to analyse competence in laparoscopic assistance. Participants The study subjects were…
A quantitative approach for assessing significant improvements in elite sprint performance: Has IGF-1 entered the arena?
2012
The introduction of doping substances and methods in sports triggers noticeable effects on physical performance in metric sports. Here, we use time series analysis to investigate the recent development in male and female elite sprinting performance. Time series displaying the average of the world's top 20 athletes were analyzed employing polynomial spline functions and moving averages. Outstanding changes in performance over time were statistically analyzed by Welch's t-test and by Cohen's measurements of effect. For validation we exemplarily show that our analysis is capable of indicating the effect of the introduction of in- and out-of-competition doping testing on women's shot put as wel…