Search results for "Modeling and simulation"
showing 10 items of 1561 documents
Inverse problems and invisibility cloaking for FEM models and resistor networks
2013
In this paper we consider inverse problems for resistor networks and for models obtained via the finite element method (FEM) for the conductivity equation. These correspond to discrete versions of the inverse conductivity problem of Calderón. We characterize FEM models corresponding to a given triangulation of the domain that are equivalent to certain resistor networks, and apply the results to study nonuniqueness of the discrete inverse problem. It turns out that the degree of nonuniqueness for the discrete problem is larger than the one for the partial differential equation. We also study invisibility cloaking for FEM models, and show how an arbitrary body can be surrounded with a layer …
An optimization-based approach for solving a time-harmonic multiphysical wave problem with higher-order schemes
2013
This study considers developing numerical solution techniques for the computer simulations of time-harmonic fluid-structure interaction between acoustic and elastic waves. The focus is on the efficiency of an iterative solution method based on a controllability approach and spectral elements. We concentrate on the model, in which the acoustic waves in the fluid domain are modeled by using the velocity potential and the elastic waves in the structure domain are modeled by using displacement.Traditionally, the complex-valued time-harmonic equations are used for solving the time-harmonic problems. Instead of that, we focus on finding periodic solutions without solving the time-harmonic problem…
MATHEMATICS IN THE CONTEXT OF FUZZY SETS: BASIC IDEAS, CONCEPTS, AND SOME REMARKS ON THE HISTORY AND RECENT TRENDS OF DEVELOPMENT
2011
The main aim of this paper is to discuss the basic ideas and concepts of the so called ‘Fuzzy Mathematics’ and to give a brief survey of the history and of some trends in recent development of mathematics and its applications in the context of fuzzy sets. As a potential reader we imagine a mathematician, who is not working in the field of ‘fuzzy mathematics’, but wishes to have some idea about this vast field in modern science.
A non-cooperative approach to the folk rule in minimum cost spanning tree problems
2023
This paper deals with the problem of finding a way to distribute the cost of a minimum cost spanning tree problem between the players. A rule that assigns a payoff to each player provides this distribution. An optimistic point of view is considered to devise a cooperative game. Following this optimistic approach, a sequential game provides this construction to define the action sets of the players. The main result states the existence of a unique cost allocation in subgame perfect equilibria. This cost allocation matches the one suggested by the folk rule. The authors thank the support of the Spanish Ministry of Science, Innovation and Universities, the Spanish Ministry of Economy and Compe…
Grooving by Nd:YAG laser treatment
2000
Abstract The properties of the laser beam have been used to produce deep and thin grooves in metals, melted material being removed with the assistance of a high velocity gas. Preliminary experiments show that the geometry and the location of the gas inlet tube are the main parameters governing the evacuation of the scoria. The influence of the nature of the materials on the depth of the grooves is discussed from examination of the grooves realized on various metals (copper, aluminum, titanium,…). Finally, a statistical study is performed to indicate the parameters that have to be controlled to secure regular grooves. It appears that the groove width is not too much affected by parameter var…
Up-wind difference approximation and singularity formation for a slow erosion model
2020
We consider a model for a granular flow in the slow erosion limit introduced in [31]. We propose an up-wind numerical scheme for this problem and show that the approximate solutions generated by the scheme converge to the unique entropy solution. Numerical examples are also presented showing the reliability of the scheme. We study also the finite time singularity formation for the model with the singularity tracking method, and we characterize the singularities as shocks in the solution.
AI ethics:an empirical study on the views of practitioners and lawmakers
2023
Artificial intelligence (AI) solutions and technologies are being increasingly adopted in smart systems contexts; however, such technologies are concerned with ethical uncertainties. Various guidelines, principles, and regulatory frameworks are designed to ensure that AI technologies adhere to ethical well-being. However, the implications of AI ethics principles and guidelines are still being debated. To further explore the significance of AI ethics principles and relevant challenges, we conducted a survey of 99 randomly selected representative AI practitioners and lawmakers (e.g., AI engineers and lawyers) from 20 countries across five continents. To the best of our knowledge, this is the …
Towards a Real-time Mitigation of High Temperature while Drilling using a Multi-agent System
2018
International audience; In oilfield wells, while drilling for several kilometers below surface, high temperature damages the drilling tools. This costs money and time for tripping operations to change the damaged tool. Existing temperature mitigation techniques have several drawbacks including a long response time, analogue signal issues and human intervention. In this work, we empower the down-hole tools with a coordination mechanism to mitigate high temperature in soft real time by controlling a down-hole actuator through a voting process. The tools are represented by agents that control the sensors and actuators embedded in these tools. To implement the proposed system properly, a model …
Adsorption and desorption surface dynamics of gaseous adsorbate on silicate-1 by molecular dynamics simulation
2013
The dynamics of adsorption and desorption of gaseous molecules on the external surface of a crystal and a membrane of zeolite silicate-1 is investigated by molecular dynamics simulation. The gases ...
ON SOME GENERALIZATION OF SMOOTHING PROBLEMS
2015
The paper deals with the generalized smoothing problem in abstract Hilbert spaces. This generalized problem involves particular cases such as the interpolating problem, the smoothing problem with weights, the smoothing problem with obstacles, the problem on splines in convex sets and others. The theorem on the existence and characterization of a solution of the generalized problem is proved. It is shown how the theorem gives already known theorems in special cases as well as some new results.