Search results for " Simulation"
showing 10 items of 4034 documents
Statistical performance of a multiclass bulk production queueing system
2004
Abstract In this paper, we discuss how to statistically analyze a make-to-stock production system the behaviour of which depends on a multiclass bulk queueing system. The performance of the system is evaluated in terms of the different demands of products, processing times and, mainly, through the finished product inventory and other related measures that quantify the queueing effects in the system. A numerical example which illustrates the applicability of the results in an inventory scenario is also discussed.
Inference and prediction in bulk arrival queues and queues with service in stages
1998
This paper deals with the statistical analysis from a Bayesian point of view, of bulk arrival queues where the batch size is considered as a fixed constant. The focus is on prediction of the usual measures of performance of the system in the steady state. The probability generating function of the posterior predictive distribution of the number of customers in the system and the Laplace transform of the posterior predictive distribution of the waiting time in the system are obtained. Numerical inversion of these transforms is considered. Inference and prediction of its equivalent single queue with service in stages is also discussed.
Generation of narrowband antisymmetric lamb waves using a formed laser source in the ablative regime
2007
A formed laser source, using a four-element lenticular array, is used in the ablative regime to generate select, narrowband, acoustic plate waves. The arrangement of the array produces acoustical signals that have frequencies compatible with the response of the broadband capacitive air-coupled transducer used in this study. A simplified concept is presented to explain the effect of a line array source on the frequency content of acoustic waves. The analytical model for a point pulse surface displacement is derived from the point load solution to Lamb's problem. The point pulse displacement elements of a line array source are summed mathematically, taking into account all applicable propagat…
A combined molecular dynamics and Monte Carlo study of the approach towards phase separation in colloid-polymer mixtures.
2011
A coarse-grained model for colloid-polymer mixtures is investigated where both colloids and polymer coils are represented as point-like particles interacting with spherically symmetric effective potentials. Colloid-colloid and colloid-polymer interactions are described by Weeks-Chandler-Andersen potentials, while the polymer-polymer interaction is very soft, of strength k(B)T/2 for maximum polymer-polymer overlap. This model can be efficiently simulated both by Monte Carlo and molecular dynamics methods, and its phase diagram closely resembles that of the well-known Asakura-Oosawa model. The static and dynamic properties of the model are presented for systems at critical colloid density, va…
An experimental approach to efficiency calibration for gamma-ray spectrometric analysis of large air particulate filters
2013
Abstract A full-energy-peak efficiency (FEPE) calibration procedure for gamma-ray spectrometric analysis of air particulate samples collected on large filters is described herein. The experimental results are obtained for an unconventional measurement geometry, termed a “packet-sample”. The sample is obtained from a large cellulose filter (45 cm×45 cm) used to collect air particulate samples that is resized to dimensions suitable for spectrometric measurements (6 cm×6 cm×0.7 cm). To determine the FEPEs, many standards were created, i.e., some filters containing a small amount of ThO 2 and others containing a known amount of KCl. Efficiency curves obtained through best fits to experimental d…
Dosimetric feasibility study for an extracorporeal BNCT application on liver metastases at the TRIGA Mainz
2010
This study investigates the dosimetric feasibility of Boron Neutron Capture Therapy (BNCT) of explanted livers in the thermal column of the research reactor in Mainz. The Monte Carlo code MCNP5 is used to calculate the biologically weighted dose for different ratios of the (10)B-concentration in tumour to normal liver tissue. The simulation results show that dosimetric goals are only partially met. To guarantee effective BNCT treatment the organ has to be better shielded from all gamma radiation.
Estimation of Personalized Minimal Purkinje Systems From Human Electro-Anatomical Maps
2021
The Purkinje system is a heart structure responsible for transmitting electrical impulses through the ventricles in a fast and coordinated way to trigger mechanical contraction. Estimating a patient-specific compatible Purkinje Network from an electro-anatomical map is a challenging task, that could help to improve models for electrophysiology simulations or provide aid in therapy planning, such as radiofrequency ablation. In this study, we present a methodology to inversely estimate a Purkinje network from a patient's electro-anatomical map. First, we carry out a simulation study to assess the accuracy of the method for different synthetic Purkinje network morphologies and myocardial junct…
A Check of Water Drop Impact Effects on Surface Soil Saturated Hydraulic Conductivity
2020
The post-tillage dynamics of the surface soil saturated hydraulic conductivity, Ks, was studied at the Masse experimental station (central Italy, silty-clay-loam soil). A sequence of experiments was performed by rainfall simulation on two replicated micro-plots (width 1 m, length 0.92 m, slope 16%) established on bare soil. Each high-intensity rainfall simulation was preceded by a low-intensity wetting phase. The soil water content, w, was measured before wetting and both before and after simulation. Runoff was measured at 5 min intervals. The infiltration rate was calculated as the difference between rainfall intensity and runoff rate. Finally, Ks was assumed to be equal to the infiltratio…
Optical rogue-wave-like extreme value fluctuations in fiber Raman amplifiers
2008
International audience; We report experimental observation and characterization of rogue wave-like extreme value statistics arising from pump-signal noise transfer in a fiber Raman amplifier. Specifically, by exploiting Raman amplification with an incoherent pump, the amplified signal is shown to develop a series of temporal intensity spikes whose peak power follows a power-law probability distribution. The results are interpreted using a numerical model of the Raman gain process using coupled nonlinear Schrödinger equations, and the numerical model predicts results in good agreement with experiment.
Evaluation of routing policies using an interval-valued TOPSIS approach for the allocation rules
2021
Abstract The success of warehouse management in a supply chain widely depends on an efficient and effective retrieve of customer orders, which is known as the picking process. This paper investigates various routing policies of pickers under two different allocation methods of items in a warehouse of fixed layout, and evaluates their performance in terms of the resulting travel distance by means of a simulation approach. The allocation strategies taken into account are the random storage and a multi-criteria approach, called Interval-Value TOPSIS (IV-T), which is expressively proposed in this paper as a new way to solve the storage allocation problem of items in a warehouse. Because of the …