Search results for "Simulation."
showing 10 items of 4779 documents
Density functional/molecular dynamics simulations of phase-change materials
2013
Does ns2 Really Simulate MPLS Networks?
2008
Multi Protocol Label Switching (MPLS) is being used in many corporate networks and public infrastructures and as a backbone technology of many Autonomous Systems. Because of its importance, what is needed is to find out simulators able to simulate MPLS networks whose results reflect the real environment as much as possible. In this article, we will show real measurements from the Railway Infrastructure Administrator (ADIF, the Spanish railway infrastructure manager) MPLS network and we will compare them with the results obtained by the freeware simulator ns2. We will check the level of reliability provided by the simulator and we will know under which parameters its results will be similar …
Strictly convergent algorithm for an elliptic equation with nonlocal and nonlinear boundary conditions
2012
The paper describes a formally strictly convergent algorithm for solving a class of elliptic problems with nonlinear and nonlocal boundary conditions, which arise in modeling of the steady-state conductive-radiative heat transfer processes. The proposed algorithm has two levels of iterations, where inner iterations by means of the damped Newton method solve an appropriate elliptic problem with nonlinear, but local boundary conditions, and outer iterations deal with nonlocal terms in boundary conditions.
Interactions and patterns between species diversity and genetic diversity
2015
A convergent validity test within the payment card format using simulation techniques
2019
International audience; A convergent validity test is performed between two groups of versions of the payment card format. The first group, the classic payment card (CPC), asks respondents to report their willingness to pay (WTP) as a point from a list of amounts, and then treats each WTP response as an interval. The second group generates WTP data that may contain both single point and interval values. It includes the two-way-payment ladder (TWPL) (respondents have to tick amounts they would definitely pay and cross amounts they would definitely not pay), and point-interval payment card (PIPC) (respondents have to tick their WTP as either a point or an interval). The test is conducted usin…
Systematic derivation of partial differential equations for second order boundary value problems
2022
Software systems designed to solve second order boundary value problems are typically restricted to hardwired lists of partial differential equations. In order to come up with more flexible systems, we introduce a systematic approach to find partial differential equations that result in eligible boundary value problems. This enables one to construct and combine one's own partial differential equations instead of choosing those from a pre-given list. This expands significantly end users possibilities to employ boundary value problems in modeling. To introduce the main ideas we employ differential geometry to examine the mathematical structure involved in second order boundary value problems …
Disease dispersion as a spatial interaction: The case of Flavescence Dorée
2020
International audience; Flavescence dorée is a serious and incurable vine disease transmitted by an insect vector. Focusing on its spatial diffusion and on its control with pesticides, this paper investigates the private strategies of wine producers and their socially optimal counterparts. The socially optimal regulation has to address two externalities regarding private treatment decisions: (a) the insufficient consideration of collective benefits from controlling the vector populations; (b) the failure to take into account environmental damage related to pesticide application. The probability of infection is estimated on French data from a spatial econometric specification. Three alternat…
A beam search algorithm for minimizing crane times in premarshalling problems
2022
The premarshalling problem consists of sorting the containers placed in a bay of the container yard so that they can be retrieved in the order in which they will be required. We study the premarshalling problem with crane time minimization objective and develop a beam search algorithm, with some new elements adapted to the characteristics of the problem, to solve it. We propose various evaluation criteria, depending on the type of container movement, for its local evaluation; a new heuristic algorithm including local search for blue its global evaluation; and several new dominance rules. The computational study shows the contribution of each new element. The performance of the complete algo…
CROSS-DOCKING TRANSSHIPMENT PROBLEM APPROACHED BY NON LINEAR PROGRAMMING AND SIMULATION ANALYSIS
2012
The need for fast product delivery causes the attention of supply chain is addressed to strategies able to optimize the distribution process. In this field the crossdocking seems to be an efficient strategy which makes possible to reduce or eliminate the storage phase by meeting customer demand. In this paper a transshipment problem for cross-docking strategy is considered by means of a deterministic model studied through the non linear programming technique. The solution found allows to determine the optimal quantities to ship, the number of routes activated and the optimal truck number when the constraint on truck capacity is enforced. The influence of the demand fluctuation is also addre…
Characterization of spatial porosity and mineral distribution of crystalline rock using X-ray micro computed tomography, C-14-PMMA autoradiography an…
2019
The spatial porosity and mineral distribution of geological materials strongly affects transport processes in them. X-ray micro computed tomography (X-mu CT) has proven to be a powerful tool for characterizing the spatial mineral distribution of geological samples in 3-D. However, limitations in resolution prevent an accurate characterization of pore space especially for tight crystalline rock samples and 2-D methods such as C-14-polymethylmethacrylate (C-14-PMMA) autoradiography and scanning electron microscopy (SEM) are needed. The spatial porosity and mineral distributions of tight crystalline rock samples from Aspo, Sweden, and Olkiluoto, Finland, were studied here. The X-mu CT were use…