In the present study, Artificial Intelligence (AI) based gene expression programming (GEP) is used to develop a model to predict the performance and emission characteristics of a single-cylinder diesel engine fueled w...
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In the present study, Artificial Intelligence (AI) based gene expression programming (GEP) is used to develop a model to predict the performance and emission characteristics of a single-cylinder diesel engine fueled with linseed oil methyl ester (LOME) blended with mineral diesel. The data to be used for GEP were obtained experimentally by varying the biodiesel/mineral diesel blending ratio, engine load, fuel injection pressure, and fuel injection timing. The GEP-based model was developed to predict the brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), NOx, and unburned hydrocarbon (UHC) emission. A major part (70%) of the collected data was used for training and remaining (30%) was used for model validation. The developed GEP model was robust enough to provide a high degree of accuracy in the prediction of engine performance and emission parameters. The statistical measure of model robustness such as coefficient of correlation (R) was in the range of 0.9926-0.9999 and the coefficient of determination (R2) was 0.9854-0.9998 for the output prediction. The root mean square error (RMSE) in the GEP model predicted results were in the range of 0.0048-2.597 and mean absolute error (MSE) was ***: AI: Artificial Intelligence;BSFC: Brake specific fuel consumption;bTDC: Before top dead center;BTE: Brake thermal efficiency;B0: (MOME 0% + Mineral diesel 100%);B10: (MOME 10% + Mineral diesel 90%);B20: (MOME 20% + Mineral diesel 80%);CI: Compression ignition;CO: Carbon monoxide;ET: expression tree;FIP: Fuel injection pressure;FIT: Fuel injection timing;GEP: gene expression programming;ICE: Internal combustion engine;ID: Ignition delay;MAE: Mean absolute error;MIT: Machine identical tool;NOx: Nitrogen oxides;ppm: Parts per million;R: Regression coefficient;R2: Coefficient of determination;RMSE: Root mean square error;UHC: Unburned hydrocarbon
Forecasting wind power is vital to ensure steady, sustainable, and renewable energy. The complex nonlinear nature of wind flow and its interrelated factors make power prediction challenging. This study predicted wind ...
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Forecasting wind power is vital to ensure steady, sustainable, and renewable energy. The complex nonlinear nature of wind flow and its interrelated factors make power prediction challenging. This study predicted wind power curves inspired by the Biologically Inspired Evolutionary Computation (BIEC) paradigm, incorporating gene expression programming (GEP), Artificial Neural Networks (ANN), Least Square Support Vector Machines (LSSVM), and Random Forest (RF) models. Key input parameters include wind speed, yaw azimuth, turbulent intensity, veer, horizontal and vertical shear, ambient temperature, blade pitch, and rotor speed. The study evaluates these models' effectiveness using root mean square error (RMSE) and correlation coefficient R. Results indicate that the GEP model offers transparent modeling, emphasizing critical inputs like wind speed, rotor speed, blade pitch angle, and temperature for wind power prediction. The GEP model identified wind speed, rotor speed, blade pitch angle, and temperature as the most influential parameters, with variable importance index (Ii) values of 69.39%, 24.39%, 5.46%, and 0.64% for training, and 69.37%, 25.03%, 4.98%, and 0.54% for validation. The study demonstrates the GEP model's efficacy in accurately forecasting wind power curve, achieving a high correlation with training and validation coefficients of 0.9899 and 0.994, respectively, outperforming traditional models with minor errors.
The consideration of the inherently non-local characteristics of turbulence is an open challenge and subject to many investigations. Recent approaches rely on the utilization of spatially configured Neural Networks su...
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The consideration of the inherently non-local characteristics of turbulence is an open challenge and subject to many investigations. Recent approaches rely on the utilization of spatially configured Neural Networks such as e.g. Convolutional Neural Networks to account for non-local effects (Comput. Methods Appl. Mech. Eng. 384:113927, 2021). Nevertheless, approaches featuring Neural Networks are not easily available for gene expression programming. An alternative option, to consider non-local effects, is the use of partial differential equations (PDE) like an additional convection-diffusion equation as is done for example in several transition models such as the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma$$\end{document}- model by Menter et al. (Flow Turbul. Combust. 583-619, 2015). Consequently, instead of only modeling a local correction factor directly using GEP, we equip the input quantities with an additional optional convection-diffusion equation of which we model the production term, diffusion constants and boundary type. The methodology is applied on a set of low pressure turbine testcases in order to find transition models. Resulting expressions are further analysed in terms of underlying mechnims and logical foundations.
Learning accurate numerical constants when developing algebraic models is a known challenge for evolutionary algorithms, such as gene expression programming (GEP). This paper introduces the concept of adaptive symbols...
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Learning accurate numerical constants when developing algebraic models is a known challenge for evolutionary algorithms, such as gene expression programming (GEP). This paper introduces the concept of adaptive symbols to the GEP framework by Weatheritt and Sandberg (J Comput Phys 325:22-37, 2016a) to develop advanced physics closure models. Adaptive symbols utilize gradient information to learn locally optimal numerical constants during model training, for which we investigate two types of nonlinear optimization algorithms. The second contribution of this work is implementing two regularization techniques to incentivize the development of implementable and interpretable closure models. We apply L2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$L_2$$\end{document} regularization to ensure small magnitude numerical constants and devise a novel complexity metric that supports the development of low complexity models via custom symbol complexities and multi-objective optimization. This extended framework is employed to four use cases, namely rediscovering Sutherland's viscosity law, developing laminar flame speed combustion models and training two types of fluid dynamics turbulence models. The model prediction accuracy and the convergence speed of training are improved significantly across all of the more and less complex use cases, respectively. The two regularization methods are essential for developing implementable closure models and we demonstrate that the developed turbulence models substantially improve simulations over state-of-the-art models.
The accurate prediction of the equivalent hydraulic aperture (EHA) in a single fracture is of paramount importance for the investigation of fracture flow capacity. Previous studies primarily relied on fitting experime...
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The accurate prediction of the equivalent hydraulic aperture (EHA) in a single fracture is of paramount importance for the investigation of fracture flow capacity. Previous studies primarily relied on fitting experimental data to obtain the EHA, failing to accurately characterize the impact of the strong nonlinearity among fracture geometric parameters on EHA. This research integrates 170 datasets of measured EHA, incorporating key geometric parameters: average mechanical aperture (bm), peak roughness height (xi), and the joint roughness coefficient (JRC). These three main geometric characteristic parameters, used as input parameters, are the primary factors influencing the EHA. The gene expression programming (GEP) method was utilized to construct a model for predicting EHA (bh). The developed GEP model was then compared with 6 existing empirical models, as well as 2 AI models (Random Forest (RF) and Support Vector Machine (SVM)). The results indicate that the GEP model (R2 = 0.997) and the SVM model (R2 = 0.9944) both demonstrate high accuracy, evidenced by the GEP model's low RMSE (0.014) and MAE (0.01) values. The sensitivity analysis indicates that in the GEP model, the hydraulic aperture increases linearly with the increase of bm, decreases linearly with the increase of xi, and initially increases but then decreases as JRC increases. These findings provide insightful contributions to the assessment of hydraulic conductivity in the rough single fracture. GEP model accurately predicts hydraulic aperture (R-2 = 0.997) with clear *** model outperforms six existing empirical & two AI models in *** m, JRC as key in hydraulic aperture, impact is *** model shows complex impact of geometry on hydraulic aperture
As per the performance grading scheme, the selection of asphalt binder for a particular location requires information on seven-day maximum and one-day minimum pavement temperatures. Pavement surface temperatures are u...
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As per the performance grading scheme, the selection of asphalt binder for a particular location requires information on seven-day maximum and one-day minimum pavement temperatures. Pavement surface temperatures are usually related to the surrounding air temperature. This study presents a methodology for developing air temperature predictive models using high resolution long-term weather data of India. gene expression programming (GEP), an evolutionary computing algorithm, was used to evaluate the expressions governing the air temperature as a function of latitude, longitude, elevation, relative humidity, wind speed, solar radiation, and rainfall intensity. A new methodology to evaluate the optimum tree depth for achieving reasonably high accuracy but at reasonably smaller tree depth was also proposed. Statistical analysis involving comparing the goodness of fit and distribution of the prediction error was conducted to understand the prediction capability of the proposed models. The statistical analysis proved the reasonably high predictive power of the geneexpressions corresponding to the optimum tree depth. The proposed seven-day maximum and one-day minimum air temperature predictive models have a very simple structure that can be used by field engineers for hand calculation with little effort.
This paper focuses on the stability analysis of three-dimensional rectangular trapdoors beneath cohesivefrictional soils via three-dimensional finite element limit analysis (3D FELA). By applying Terzaghi's superp...
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This paper focuses on the stability analysis of three-dimensional rectangular trapdoors beneath cohesivefrictional soils via three-dimensional finite element limit analysis (3D FELA). By applying Terzaghi's superposition method, the average upper bound and lower bound limit analyses are conducted to determine three stability factors: the cohesion factor (Fc), the surcharge factor (Fs), and the unit weight factor (Fr). Additionally, a machine learning technique, specifically genetic expressionprogramming (GEP), is employed to develop explicit predictive equations for each stability factor. The numerical results show excellent performance of the GEP model prediction, with R2 values of 0.991, 0.992, and 0.994 for the cohesion, surcharge, and unit weight stability factors, respectively. A series of equations, figures, and tables were subsequently developed to determine the stability factors of a rectangular trapdoor. The incorporation of modern machine learning techniques with advanced 3D FELA makes this study highly significant for geotechnical engineering practices.
The present work aims to propose a model for calculating unconfined compressive strength (UCS) of soil stabilized by geopolymer based on gene expression programming (GEP). The new model is compared with earlier models...
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The present work aims to propose a model for calculating unconfined compressive strength (UCS) of soil stabilized by geopolymer based on gene expression programming (GEP). The new model is compared with earlier models developed from artificial neural networks (ANN), multivariable regression analysis (MVR), multi-genegenetic programming (MGGP), and support vector machines (SVM) models. The results indicate that the GEP model is superior to MVR and MGGP models and quite comparable to ANN and SVM models. The study demonstrates the robustness of the GEP model through parametric analysis. Additionally, this model is simpler and easier to use in practice.
Given the growing concern over global warming and the critical role of carbon dioxide(CO_(2))in this phenomenon,the study of CO_(2)-induced alterations in coal strength has garnered significant attention due to its im...
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Given the growing concern over global warming and the critical role of carbon dioxide(CO_(2))in this phenomenon,the study of CO_(2)-induced alterations in coal strength has garnered significant attention due to its implications for carbon sequestration.A large number of experiments have proved that CO_(2) interaction time(T),saturation pressure(P)and other parameters have significant effects on coal ***,accurate evaluation of CO_(2)-induced alterations in coal strength is still a difficult problem,so it is particularly important to establish accurate and efficient prediction *** study explored the application of advancedmachine learning(ML)algorithms and gene expression programming(GEP)techniques to predict CO_(2)-induced alterations in coal *** were developed,including three metaheuristic-optimized XGBoost models(GWO-XGBoost,SSA-XGBoost,PO-XGBoost)and three GEP models(GEP-1,GEP-2,GEP-3).Comprehensive evaluations using multiple metrics revealed that all models demonstrated high predictive accuracy,with the SSA-XGBoost model achieving the best performance(R2—Coefficient of determination=0.99396,RMSE—Root Mean Square Error=0.62102,MAE—Mean Absolute Error=0.36164,MAPE—Mean Absolute Percentage Error=4.8101%,RPD—Residual Predictive Deviation=13.4741).Model interpretability analyses using SHAP(Shapley Additive exPlanations),ICE(Individual Conditional Expectation),and PDP(Partial Dependence Plot)techniques highlighted the dominant role of fixed carbon content(FC)and significant interactions between FC and CO_(2) saturation pressure(P).Theresults demonstrated that the proposedmodels effectively address the challenges of CO_(2)-induced strength prediction,providing valuable insights for geological storage safety and environmental applications.
The inverse design of molecules has attracted widespread attention in the field of chemical molecular design. However, existing methods fail to address the diversity of the generated molecules. In this work, we propos...
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The inverse design of molecules has attracted widespread attention in the field of chemical molecular design. However, existing methods fail to address the diversity of the generated molecules. In this work, we propose a molecule generation method called GEP-DNN4Mol to generate molecules with good diversity and desired properties in the exploration of vast chemical space. GEP-DNN4Mol leverages a special gene expression programming algorithm as a generator for molecular generations, uses a deep neural network as an evaluator to guide the update of the generator by extracting the molecular features of the generated molecules, and couples with SMILES and SELFIES molecular representations. The experimental results show that the proposed approach outperforms the state-of-the-art methods in the performance of generated molecules and the efficiency of exploration in chemical space. The molecules generated by GEP-DNN4Mol have advantages in terms of total validity, high novelty, and good diversity.
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