Search results for "Simulation model"
showing 10 items of 68 documents
Traffic simulation models calibration using speed–density relationship: An automated procedure based on genetic algorithm
2016
Calibration of traffic models.Calibration as optimization problem.Use of genetic algorithm. This paper presents the first results of a research which applied a genetic algorithm to calibrate a microscopic traffic simulation model based on speed-density relationships. A large set of traffic data collected from the A22 Freeway, Italy, was used and a comparison was performed between the field measurements and the simulation outputs obtained for a test freeway segment by using the Aimsun microscopic simulator.The calibration was formulated as an optimization problem to be solved based on a genetic algorithm; the objective function was defined in order to minimize the differences between the sim…
Buildings integrated phase change materials: Modelling and validation of a novel tool for the energy performance analysis
2017
In this paper a novel dynamic energy performance simulation model for the Phase Change Materials (PCM) analysis is presented. The model is implemented in a suitable computer code, written in MatLab and called DETECt, for complete building energy analyses. In the presented model, the “effective specific heat” method is implemented. Here, the specific heat of each PCM layer changes as a function of the system phase and temperature in both melting and freezing processes. A model validation is carried out by comparing numerical results vs. measurements obtained at Solar Laboratory of Concordia University (Montreal, Canada). The simulation model allows exploring the potential of PCMs to increase…
Fitting particle size distribution models to data from Burundian soils for the BEST procedure and other purposes
2009
Testing the Beerkan Estimation of Soil Transfer (BEST) soil particle size distribution (PSD) model is necessary to evaluate the applicability of the BEST procedure for characterising soil hydraulics. In this investigation, the fitting performance of the BEST PSD model was tested using a database of 114 Burundian soils with 14 measured particle size fractions for each soil sample, and also by considering a reduced number of measured particle size fractions for a sample. The fitting performance of the model developed by Fredlund et al. (2000) (FR model) was also considered for comparative purposes. On average, the BEST model yielded satisfactory results (i.e., mean relative error, E r ¯ = 3.9…
Estimation of Passenger Car Equivalents for single-lane roundabouts using a microsimulation-based procedure
2017
Calibration of microscopic traffic simulation models for single-lane roundabouts.Use of a meta-analytical estimation of critical and follow up headways.Use of a genetic algorithm-based procedure.Calculation of passenger car equivalents for single-lane roundabouts. Passenger car equivalents for heavy vehicles are required to carry out capacity calculations and perform operational analysis of any road entity (roadway segments or intersections). At single-lane roundabouts, the constraints to the vehicular trajectories imposed by the curvilinear geometric design and the driver's gap acceptance behaviour are expected to produce an impact of the heavy vehicles on the quality of traffic flow diffe…
The impact of thermophysical properties and hysteresis effects on the energy performance simulation of PCM wallboards: Experimental studies, modellin…
2020
Abstract This paper presents a combined experimental and numerical procedure, developed to test the thermophysical behaviour of a real scale PCM wallboard, aiming at providing reliable data for the validation of building energy performance simulation tools. Data obtained from two experimental tests, conducted on real building elements integrating PCM undergoing complete and incomplete phase change, are considered for assessing the impact of thermal properties and hysteresis. A comprehensive comparative numerical analysis, performed by means of an in-house developed simulation tool, called DETECt, is carried out to investigate the reliability of several modelling and simulation approaches av…
Building dynamic balanced scorecards to enhance strategy design and planning in public utilities. Key-findings from a project in a city water company
2006
Increasing complexity and uncertainty of both business internal and external variables determines a growing need for prompt and accurate information. On this concern, in the last decade, there has been an increasing effort to provide public utilities with tools aimed to support decision makers in planning and control, by taking into account not only operational but also strategic issues. Among them, for 1instance, customer satisfaction, internal business process efficiency, business image, and bargaining power against other counterparts (e.g. the municipal administration). Often, however, such an effort has been oriented to generate a large volume of data, only focused on financial indicato…
Proposal of a neuro-fuzzy model of a WWW server
2005
This paper presents the ways of designing simulation models of Web servers. At the beginning queuing network models are introduced, those models are generally known and often used in the initial phase of research on particular technical solutions. Next, an entirely new approach to the issue discussed is presented - neuro-fuzzy models, thanks to which, it is possible to automate the process of designing simulation models. The results of comparative tests of these two models are presented. Based on these results it can be concluded that neuro-fuzzy models are accurate and can be used in simulation research.
Multivariate Statistical Analysis for Water Demand Modeling
2014
The actual level of water demand is the driving force behind the hydraulic dynamics in water distribution systems. Consequently, it is crucial to estimate it as accurately as possible in order to result in reliable simulation models. In this paper, a copula-based multivariate analysis has been proposed and used for demand prediction for given return period. The analysis is applied to water consumption data collected in the water distribution network of Palermo (Italy). The approach showed to produce consisted demand patterns and to be a powerful tool to be coupled with water distribution network models for design or analysis problems. (C) 2014 Published by Elsevier Ltd.
Sensitivity of Regional Water Supply Systems Models to the Level of Skeletonization – A Case Study from Apulia, Italy
2015
AbstractSimulation models supported by state-of-the-art software packages are nowadays available to explore operation rules of regional water supply systems or to select structural alternatives for improving long-term service performances.Given the, sometimes high, complexity of these systems, model calibration can become a lengthy procedure and many runs are necessary before obtaining convincing results. However, even after calibration, depending on system's complexity and the number of time steps investigated, a single run can take up to several minutes, even on state-of-the-art computers, so that simulation time can become a true bottleneck if such models are to be coupled with metaheuri…