Search results for "Applied Mathematic"
showing 10 items of 4398 documents
A new inter-cloud service-level guarantee protocol applied to space missions
2017
Nowadays, the term cloud computing often falsely assumes the availability of an unlimited pool of resources. On the contrary, if a cloud provider reaches its limits, it may pose the risk of breaking their service level agreement (SLA). Space agencies could start using the cloud computing model within their IT infrastructure with multiple ground control points around the world to reduce the cost. An inter-cloud communication protocol with a guarantee of the service level will significantly reduce the cost if each ground control segment is considered as a cloud provider. This paper outlines a new protocol that was developed to take into consideration the end-to-end service-level guarantee. Th…
Some conventional and unconventional educational column stability Problems
2006
Two interesting problems are considered for enriching the curriculum of the Strength of Materials course, in the light of recently developed functionally graded materials (FGMs), characterized with the smooth variation of the elastic modulus. These are problems associated with buckling of columns with variable flexural rigidity along the axis of the column. A simple semi-inverse method is proposed for determining closed-form solutions of axially inhomogeneous columns. In order for the presentation to be given in one package, the conventional problems are also recapitulated along with the novel ones. The main approach adopted here is the use of the second-order differential equation, instea…
The dynamics over the next few years of the Spanish mobile telecommunications market share: a mathematical modelling approach
2013
Taking into account available data from 2002 to 2009 about the market share percentages of the Spanish mobile telecommunications service providers, a dynamic diffusion model to study the evolution of the clients’ change between the different companies during the period 2010–2016 is proposed. The constructed model provides a tool for forecasting short-term trends about the customers’ preferences with respect to mobile network operators taking into account both, autonomous decisions due to direct marketing and advertising strategies, and also decisions adopted through interaction via social influence. The model can provide insights to companies for designing strategies in order to gain market…
The design of sum-of-cisoids rayleigh fading channel simulators assuming non-isotropic scattering conditions
2010
In this letter, we introduce the Riemann sum method (RSM) as an effective tool for the design of sum-of-cisoids (SOC) simulators for narrowband mobile Rayleigh fading channels under non-isotropic scattering conditions. We compare the performance of the RSM with that of the generalized method of equal areas (GMEA) and the Lp-norm method (LPNM), which were until now the only methods available for the design of SOC simulators for non-isotropic scattering channels. The obtained results indicate that the RSM is better suited than the GMEA and the LPNM to emulate the channel's autocorrelation function (ACF), whereas the latter two methods are more precise regarding the approximation of the envelo…
Large-eddy simulations of turbulent flow with heat transfer in simple and complex geometries using Harwell-FLOW3D
1996
Abstract Large-eddy simulation (LES) results are presented and discussed for the turbulent flow with heat transfer in different geometrical configurations, including a plane channel, a channel bearing transverse square ribs on one of the walls, and a crossed-corrugated air heater. They were obtained using the computational fluid dynamics (CFD) code Harwell-FLOW3D (Release 2), finite-volume grids having up to 423 nodes, and the Smagorinsky subgrid model with several variants regarding near-wall damping and wall boundary conditions. The first problem (plane turbulent Poiseuille flow with heat transfer) was mainly used as a benchmark to investigate the influence of numerical methods (pressure-…
Computer-Aided Simulation of Die Filling Processes
1989
Summary A numerical method for analysing the filling of axisymmetrical dies of complex shape is proposed. The method, which is a further development of a LP finite element model, is able to take into account the contact conditions directly in the mathematical formulation of the problem. In such a way the solution of the die filling process is obtained by solving a LP problem, avoiding problems of numerical convergence and the heavier calculations requested by other iterative methods.
Monte Carlo simulation of the glass transition in polymer melts: An application of MCT
1995
Abstract This paper reviews the results of a large scale Monte Carlo simulation for the dynamics of a supercooled polymer melt. The dynamics of the melt was studied by means of the time evolution of the incoherent intermediate scattering function φs q(t), which was monitored over seven decades in time. In an intermediate time window it is possible to describe the decay of φs q(t) quantitatively in the framework of mode-coupling theory, provided the extended version of the theory is used.
Energy-stable linear schemes for polymer-solvent phase field models
2017
We present new linear energy-stable numerical schemes for numerical simulation of complex polymer-solvent mixtures. The mathematical model proposed by Zhou, Zhang and E (Physical Review E 73, 2006) consists of the Cahn-Hilliard equation which describes dynamics of the interface that separates polymer and solvent and the Oldroyd-B equations for the hydrodynamics of polymeric mixtures. The model is thermodynamically consistent and dissipates free energy. Our main goal in this paper is to derive numerical schemes for the polymer-solvent mixture model that are energy dissipative and efficient in time. To this end we will propose several problem-suited time discretizations yielding linear scheme…
Formalisation and methods of analysis of the fast xenobiotic mass transfer in the body
2009
The use of topological models in analytical chemistry
2005
In the present paper, the possible analytical applications of two toplogical models, the DARC model and the group contribution model, are discussed. Both models are applied to obtain calibration laws, which relate UV and IR characteristics with the chemical structure of ethylene oxide condensates. The group contribution model is also applied to determine the contribution of each part of the different compounds involved in a chemical interaction process, having established the sensitization parameters of benzodiazepines and anionic surfactants from the micellar enhancement fluorescence.