Genetic optimization for engine combustion system calibration: A case study of optimization performance sensitivity to algorithm search parameters

2021 ◽  
pp. 1-32
Author(s):  
Andrew Mansfield ◽  
Varun Chakrapani ◽  
Qingyu Li ◽  
Margaret Wooldridge
Keyword(s):  
Mutation Rate ◽  
Genetic Optimization ◽  
Combustion System ◽  
Convergence Criteria ◽  
Engine Calibration ◽  
Performance Sensitivity ◽  
Number Of Genes ◽  
Parameter Values ◽  
Algorithm Search

Abstract The use of genetic optimization algorithms (GOA) has been shown to significantly reduce the resource intensity of engine calibration, motivating investigation into the development of these methods. The objective of this work was to quantify the sensitivity of GOA performance to the algorithm search parameter values, in a case study of engine calibration. A GOA was used to calibrate four combustion system control parameters for a direct-injection gasoline engine at a single operating condition, with an optimization goal to minimize brake specific fuel consumption (BSFC) for a specified engine-out NOx concentration limit. The calibration process was repeated for two NOx limit values and a wide range of values for five GOA search parameters, including the number of genes, mutation rate, and convergence criteria. Results indicated GOA performance is very sensitive to algorithm search parameter values, with converged calibrations yielding BSFC values from 1 to 14% higher than the global minimum value, and the number of iterations required to converge ranging from 10 to 3,000. Broadly, GOA performance sensitivity was found to increase as the NOx limit was decreased from 4,500 to 1,000 ppm. GOA performance was the most sensitive to the number of genes and the gene mutation rate, whereas sensitivity to convergence criteria values was minimal. Identification of one set of algorithm search parameter values which universally maximized GOA performance was not possible as ideal values depended strongly on engine behavior, NOx limit, and the maximum level of error acceptable to the user.

scholarly journals AN INVESTIGATION ON THE IMPROVEMENT OF CONSTRUCTION EXPENDITURE FORECASTING

2013 ◽  
Vol 19 (5) ◽  
pp. 759-711 ◽  
Author(s):  
Andrew Ross ◽  
Katie Dalton ◽  
Begum Sertyesilisik
Keyword(s):  
Cash Flow ◽  
Construction Projects ◽  
Case Study Research ◽  
Research Strategy ◽  
Flow Models ◽  
Improved Model ◽  
Work Affect ◽  
Cash Flow Forecast ◽  
Parameter Values

This study aims to determine the accuracy of the cash flow models and to investigate if these models could be more accurate if they accounted for the potentially influential variables specific to individual construction projects. An analytical case study research strategy has been implemented in collecting data for the construction projects. The data collected has been tested against recognised models. Statistical analyses have been carried out on the data for the specified variables, culminating in the potential proposal of an improved model with respect to these identified variables. The results revealed that the independent variables (type of construction, procurement route and type of work) affect the cash flow forecast. The findings suggested that a model could be more accurate with the input of more job-specific variables and that Hudson's DHSS model is best suited to a construction project procured traditionally. Adopting the ‘trial and error’ approach, Hudson's DHSS model has been recognised as an accurate model that could be adapted slightly, through changing the parameter values. The clients and the contractors are the main beneficiaries approached for this study.

scholarly journals Monte Carlo ice flow modeling projects a new stable configuration for Columbia Glacier, Alaska, by c. 2020

2012 ◽  
Vol 6 (2) ◽  
pp. 893-930 ◽  
Author(s):  
W. Colgan ◽  
W. T. Pfeffer ◽  
H. Rajaram ◽  
W. Abdalati
Keyword(s):  
Monte Carlo ◽  
Dynamic Equilibrium ◽  
Stable Configuration ◽  
Ice Flow ◽  
Wide Range ◽  
Ensemble Mean ◽  
Iceberg Calving ◽  
Calving Rate ◽  
Parameter Values

Abstract. Due to the abundance of observational datasets collected since the onset of its retreat (c. 1983), Columbia Glacier, Alaska, provides an exciting modeling target. We perform Monte Carlo simulations of the form and flow of Columbia Glacier, using a 1-D (depth-integrated) flowline model, over a wide range of parameter values and forcings. An ensemble filter is imposed following spin-up to ensure that only simulations which accurately reproduce observed pre-retreat glacier geometry are retained; all other simulations are discarded. The selected ensemble of simulations reasonably reproduces numerous highly transient post-retreat observed datasets with a minimum of parameterizations. The selected ensemble mean projection suggests that Columbia Glacier will achieve a new dynamic equilibrium (i.e. "stable") ice geometry c. 2020, by which time iceberg calving rate will have returned to approximately pre-retreat values. Comparison of the observed 1957 and 2007 glacier geometries with the projected 2100 glacier geometry suggests that, by 2007, Columbia Glacier had already discharged ∼83 % of its total sea level rise contribution expected by 2100. This case study therefore highlights the difficulties associated with the future extrapolation of observed glacier mass loss rates that are dominated by iceberg calving.

scholarly journals An Analysis of A Three-Phase Versus A Four-Phase Traffic Lights Regulation for A Four-Leg Intersection

2020 ◽  
Vol 26 (2) ◽  
pp. 192-201
Author(s):  
Sri Redjeki Pudjaprasetya ◽  
Dear Michiko Noor
Keyword(s):  
Traffic Management ◽  
Traffic Density ◽  
Traffic Light ◽  
Traffic Lights ◽  
Characteristic Lines ◽  
Three Phase ◽  
Light Management ◽  
Phase Regulation ◽  
Parameter Values

Traffic management of intersections is an important factor that can determine traffic density at the intersection, as well as its surrounding. Long traffic queues we encounter in daily life, were often caused by ineffectiveness of traffic lights management of the cross sections.In this article, an analytic study of traffic light management of a four-leg intersection, based on the kinematic LWR model, was presented. Comparison was based on observing the end of queues over three cycles of red-green lights, under the assumption of a constant traffic flux. On every leg of the intersection, the end of the queues were obtained from characteristic lines of the shock waves.From these observations, the three phase regulation was preferred over the four-phase one. Finally, a case study of Taman Sari - Baltos intersection located in Bandung City, Indonesia, was discussed. Parameter values used in these simulations were obtained from direct observation. 

scholarly journals Comparison of different algorithms for simultaneous estimation of multiple parameters in kinetic metabolic models

2010 ◽  
Vol 7 (3) ◽  
Author(s):  
Syed Murtuza Baker ◽  
Kai Schallau ◽  
Björn H. Junker
Keyword(s):  
Parameter Estimation ◽  
Computational Models ◽  
Optimization Methods ◽  
Optimization Techniques ◽  
Simultaneous Estimation ◽  
Multiple Parameters ◽  
Reliable Parameter ◽  
Metabolic Models ◽  
Parameter Values

SummaryComputational models in systems biology are usually characterized by a lack of reliable parameter values. This is especially true for kinetic metabolic models. Experimental data can be used to estimate these missing parameters. Different optimization techniques have been explored to solve this challenging task but none has proved to be superior to the other. In this paper we review the problem of parameter estimation in kinetic models. We focus on the suitability of four commonly used optimization techniques of parameter estimation in biochemical pathways and make a comparison between those methods. The suitability of each technique is evaluated based on the ability of converging to a solution within a reasonable amount of time. As most local optimization methods fail to arrive at a satisfactory solution we only considered the global optimization techniques. A case study of the upper part of Glycolysis consisting 15 parameters is taken as the benchmark model for evaluating these methods.

Design Shell for Parametric Design at Embodiment Stage

2003 ◽  
Author(s):  
Adwait Vaidya ◽  
Jami Shah
Keyword(s):  
Parametric Design ◽  
Problem Definition ◽  
Design Stage ◽  
Embodiment Design ◽  
System Requirements ◽  
Parameter Values ◽  
Domain Independent

The embodiment design stage involves determination of geometric sizes, key parameter values, and matching of component variables to system requirements. This embodiment design stage can be parametrically represented as an iterative design-redesign problem. This paper presents a domain independent characterization of such problems; the characterization includes problem definition, design relations/procedures, and measures of goodness. The paper also discusses representation issues and solution techniques for design-redesign problems. Design tasks are differentiated as domain independent or problem specific and the scope of each design task with respect to the characterization is delineated. A Design Shell implemented on the basis of this characterization is described. This shell can be configured for evaluating designs in any domain. A case study illustrates the use of this Design Shell in characterizing a specific design problem and exploring its design space.

scholarly journals What is Missing from the Prescription of Hydrology for Land Surface Schemes?

2016 ◽  
Vol 17 (7) ◽  
pp. 2013-2039 ◽  
Author(s):  
Bruce Davison ◽  
Alain Pietroniro ◽  
Vincent Fortin ◽  
Robert Leconte ◽  
Moges Mamo ◽  
...  
Keyword(s):  
Land Surface ◽  
River Flow ◽  
Surface Heterogeneity ◽  
Heat Fluxes ◽  
Hydrologic Models ◽  
Land Surface Water ◽  
Weather And Climate ◽  
Central Canada ◽  
Parameter Values

Abstract Land surface schemes (LSSs) are of potential interest both to hydrologists looking for innovative ways to simulate river flow and the land surface water balance and to atmospheric scientists looking to improve weather and climate predictions. This paper discusses three ideas, which are grounded in hydrological science, to improve LSS predictions of streamflow and latent heat fluxes. These three possibilities are 1) improved representation of lateral flow processes, 2) the appropriate representation of surface heterogeneity, and 3) calibration to streamflow as a way to account for parameter uncertainty. The current understanding of lateral hydrological processes is described along with their representation of a selected group of LSSs. Issues around spatial heterogeneity are discussed, and calibration in hydrologic models and LSSs is examined. A case study of an evapotranspiration-dominated basin with over 10 years of extensive observations in central Canada is presented. The results indicate that in this particular basin, calibration of streamflow presents atmospheric modelers with a unique opportunity to improve upon the current practice of using lookup tables to define parameter values. More studies are needed to determine if model calibration to streamflow is an appropriate method for generally improving LSS-modeled heat fluxes around the globe.

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