Search results for "SIMULATION"
showing 10 items of 5095 documents
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…
Modelling the cement-latex interactions : experimental and simulation approach : Consequences on the rheological propertiec
2014
Latex is used in industrial mortars to improve the material properties. This behaviour is obviously related to the interactions between cement phases and latex which are still not understood. In this frame, the aim of the present work is to understand the role of latexes in mortar in particular how the various latex characteristics, such as the latex chemistry surface, or the latex size, influence the characteristics of this complex granular system. The major issue concerns the reactivity of the cement: indeed, several parameters are modified during cement hydration which governs the development of the paste mechanical properties. Consequently in order to avoid side effects due to cement hy…
Leading Edge Erosion of Wind Turbine Blades: Effects of Environmental Parameters on Impact Velocities and Erosion Damage Rate
2021
Abstract Leading edge erosion (LEE) of a wind turbine blade (WTB) is a complex phenomenon that contributes to high operation and maintenance costs. The impact between rain droplets and rotating blades exerts cyclic fatigue stresses on the leading edge — causing progressive material loss and reduced aerodynamic performance. One of the most important parameters for erosion modelling and damage prediction is the relative impact velocity between rain droplets and rotating blade and depends upon the environmental conditions. The environmental condition, in general, could vary for onshore and offshore wind turbines (OWTs) — for instance, the presence of wave-induced loads along with less turbulen…
Adaptive use patterns of secondary school classroom environments
2006
Purpose – The purpose of this research is to investigate how secondary school teachers adaptively make use of the classroom learning environment. The approach illustrates the intimate relationship between teaching style, learning style and the adaptive use of space as well as the preferences for different learning environments.Design/methodology/approach – A multi method study approach was used to carry out the research. Two main methods were used in the study. In the first method, trainee teachers recorded spatial observations (mapping). Maps of the chemistry classrooms were produced. The observers marked all fixed, semi‐fixed and flexible elements in the classroom space. The second method…
Fixed point theorems in generalized partially orderedG-metric spaces
2010
In this paper, we consider the concept of a $\Omega$-distance on a complete partially ordered G-metric space and prove some fixed point theorems.