Search results for " Simulation"
showing 10 items of 4034 documents
Minding morality : ethical artificial societies for public policy modeling
2020
AbstractPublic policies are designed to have an impact on particular societies, yet policy-oriented computer models and simulations often focus more on articulating the policies to be applied than on realistically rendering the cultural dynamics of the target society. This approach can lead to policy assessments that ignore crucial social contextual factors. For example, by leaving out distinctive moral and normative dimensions of cultural contexts in artificial societies, estimations of downstream policy effectiveness fail to account for dynamics that are fundamental in human life and central to many public policy challenges. In this paper, we supply evidence that incorporating morally sal…
Computational fluid dynamics of the ascending aorta before the onset of type A aortic dissection.
2016
We performed a pre-dissection computational fluid analysis of an ascending aortic aneurysm associated with unicuspid aortic valve. The analysis showed an abnormal helical flow pattern inside the aneurysm and an increased wall stress on the right postero-lateral wall of the ascending aorta. These values were largely higher than the theoretical cut-off for aortic wall dissection, their topographic distribution followed the intimal tear site as subsequently diagnosed by computed tomography scan and confirmed during the operation for dissection repair.
Anatomic and flow dynamic considerations for safe right axillary artery cannulation.
2013
Objectives Neuroprotection is of paramount interest in cardiac surgery. Right axillary artery cannulation is well established in aortic surgery because it significantly improves survival and outcome, but malperfusion of the right brain after direct cannulation has been reported. Anatomically, 4 vessel segments are potentially amenable for cannulation of the subclavian and axillary arteries. Clinical studies vary widely in dissection sites and cannulation techniques. We investigated critical flow dynamics in the right brain caused by arterial inflow after direct cannulation and specified cannulation positions that provide optimal cerebral perfusion. Methods Distances from the lateral margin …
Prognostic scoring system predictive of survival after surgical resection of esophageal carcinoma.
2013
BACKGROUND The aim of our study was to develop a prognostic index score for patients undergoing surgical resection for esophageal cancer that accurately determines survival with specific clinicopathological characteristics. METHODS Clinical, histological, and demographical variables of 475 patients were entered in an univariate and multivariate regression model, followed by individual calculation of the Prognostic Indicator Score and model validation via simulation. RESULTS Significant variables included in the scoring system were number of positive lymph nodes, pT, pL, R, obesity, and American Society of Anesthesiologist classification. Survival probability and its associated hazard functi…
Importance of ligand speciation in environmental research:A case study
2001
The speciations of EDTA and DTPA in process, waste and river waters are modelled and simulated, specifically to the mode of occurrence in the pulp and paper mill effluents and subsequently in receiving waters. Due to relatively short residence times in bleaching process and waste water treatment and slow exchange kinetics, it is expected that the thermodynamic equilibrium is not necessarily reached. Therefore, the initial speciation plays a key role. As such, the simulations have been extended to the process waters of the pulp and paper industry taking into account estimated average conditions. The results reveal that the main species are; Mn and Ca complexes of EDTA and DTPA in pulp mill p…
Applied multi-pulsed laser in surface treatment and numerical–experimental analysis
2011
International audience; This paper presents a comparison between simulation and experimental results of the melting process of metallic material by a pulsed laser source Nd–YAG. The simulations of temperature and velocity fields of melted material were done by solving the transient heat transfer and fluid-flow equations. Variations of the thermophysical properties were considered. Furthermore, the model included the effects of the surface-tension gradient on the fluid surface and the buoyancy force. The simulation was useful in improving our understanding of the phenomena occurring in the treated material. Using a laser triangulation sensor, an experimental study was also conducted on the s…
A constructive approach of invariants of behavior laws with respect to an infinite symmetry group – Application to a biological anisotropic hyperelas…
2014
Abstract In this paper, six new invariants associated with an anisotropic material made of one fiber family are calculated by presenting a systematic constructive and original approach. This approach is based on the development of mathematical techniques from the theory of invariants: • Definition of the material symmetry group. • Definition of the generalized Reynolds Operator. • Calculation of an integrity basis for invariant polynomials. • Comparison between the new (constructed) invariants and the classical ones.
phi-Best proximity point theorems and applications to variational inequality problems
2017
The main concern of this study is to introduce the notion of $$\varphi $$ -best proximity points and establish the existence and uniqueness of $$\varphi $$ -best proximity point for non-self mappings satisfying $$(F,\varphi )$$ -proximal and $$(F,\varphi )$$ -weak proximal contraction conditions in the context of complete metric spaces. Some examples are supplied to support the usability of our results. As applications of the obtained results, some new best proximity point results in partial metric spaces are presented. Furthermore, sufficient conditions to ensure the existence of a unique solution for a variational inequality problem are also discussed.
Stability of the Calderón problem in admissible geometries
2014
In this paper we prove log log type stability estimates for inverse boundary value problems on admissible Riemannian manifolds of dimension n ≥ 3. The stability estimates correspond to the uniqueness results in [13]. These inverse problems arise naturally when studying the anisotropic Calderon problem. peerReviewed
Global functorial hypergestures over general skeleta for musical performance
2016
Musical performance theory using Lagrangian formalism, inspired by physical string theory, has been described in previous research. That approach was restricted to zero-addressed hypergestures of local character, and also to digraph skeleta of simple arrow type. In this article, we extend the theory to hypergestures that are defined functorially over general topological categories as addresses, are global, and are also defined for general skeleta. We also prove several versions of the important Escher Theorem for this general setup. This extension is highly motivated by theoretical and practical musical performance requirements of which we give concrete examples.