4,350 results
Search Results
2. A System Identification Framework for Modeling Complex Combustion Dynamics Using Support Vector Machines
- Author
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Janakiraman, Vijay Manikandan, Nguyen, XuanLong, Sterniak, Jeff, Assanis, Dennis, Ferrier, Jean-Louis, editor, Bernard, Alain, editor, Gusikhin, Oleg, editor, and Madani, Kurosh, editor
- Published
- 2014
- Full Text
- View/download PDF
3. Analyses of Two Different Regression Models and Bootstrapping
- Author
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Gokalp, Fulya, Klatte, Diethard, editor, Lüthi, Hans-Jakob, editor, and Schmedders, Karl, editor
- Published
- 2012
- Full Text
- View/download PDF
4. Nanostructured Waste Paper Ash Treated Lateritic Soil and Its California Bearing Ratio Optimization
- Author
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Kennedy C. Onyelowe
- Subjects
020209 energy ,0211 other engineering and technologies ,Waste paper ,Soil science ,02 engineering and technology ,California bearing ratio ,021105 building & construction ,Soil stabilization ,Linear regression ,Soil water ,0202 electrical engineering, electronic engineering, information engineering ,Classification methods ,Water content ,Nonlinear regression ,Mathematics - Abstract
The stabilization potentials of NWPA and the CBR optimization were investigated on the treated olokoro lateritic soil. The soil was classified as an A-2-7 soil according to AASHTO classification method. From the stabilization procedure, it has been found that the admixture improved the strength characteristics of the stabilized lateritic soil for use as base material in pavement construction. With the laboratory results, a nonlinear regression relationship was formulated through the multiple regression algorithms for the California bearing ratio (R) as a dependent variable with optimum water content (w), maximum dry density (D), and percentage by weight additive of NWPA (SA) as the independent variables. The nonlinear relationship was linearized to enable the optimization operation with Simplex Linear Programming (Optimization) to be conducted. This iteration procedure was conducted and the results showed that the CBR (R) was optimized at Rmax=219.16% with x1= 48.103, x2=4.833, x3=13.45, and x4= 0.948 in the stabilization of lateritic soils with NWPA as an admixture applied in the percentages of 0, 3, 6, 9, 12, and 15%.
- Published
- 2017
5. Biodrying of pulp and paper secondary sludge: kinetics of volatile solids biodegradation
- Author
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César Huiliñir and Manuel Villegas
- Subjects
Paper ,Environmental Engineering ,Kinetics ,Bioengineering ,engineering.material ,Desiccation ,Waste Management and Disposal ,Water content ,Kinetic model ,Sewage ,Renewable Energy, Sustainability and the Environment ,Chemistry ,Pulp (paper) ,Air ,Environmental engineering ,Temperature ,Humidity ,General Medicine ,Biodegradation ,Models, Theoretical ,Pulp and paper industry ,Lower temperature ,Biodegradation, Environmental ,engineering ,Biodrying ,Volatilization ,Nonlinear regression ,Biotechnology - Abstract
This study focuses on the kinetics of volatile solids (VS) biodegradation of the biodrying process using pulp and paper secondary sludge. The experiments were carried out with air-flow rates of 0.51, 1.61, 3.25 and 5.26 L/min kg VS ) and initial moisture content of 64–66% w.b. Using five kinetic models and a nonlinear regression method, kinetic parameters were estimated and the models were analyzed with two statistical indicators. Higher air-flow rates cause greater moisture content reduction, lower temperature in the matrix, and lower VS reduction. At an air-flow rate as high as 5.26 L/min kg VS there is no biodrying but only convective drying. The kinetic models used successfully simulate the VS biodegradation under biodrying conditions, with a root mean square error (RMSE) between 0.007929 and 0.02744. In conclusion, we show for the first time that VS biodegradation in the biodrying process can be successfully modeled with a kinetic model.
- Published
- 2013
6. Estimation of Effective Length of Type-A Grounding System According to IEC 62305-3 Using a Machine Learning Regression Model.
- Author
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Lovrić, Dino, Krolo, Ivan, and Jurić-Grgić, Ivica
- Abstract
Two types of grounding systems are recommended for use in the international standard IEC 62305-3, Part 3: Physical damage to structures and life hazard. One of these is a radial-based grounding system (type-A), which is used in soil resistivities of up to 3000 Ω m and is considered in this paper. It is a well-known fact that during lightning strikes, only a part of the grounding wire contributes to dissipating the lightning current into the surrounding soil. This effective part of the grounding system depends on several features, such as soil resistivity, burial depth, and rise time of the dissipated lightning current. The effect of all of these features on the effective length of the type-A grounding system is explored in this paper. A suitable supervised machine learning regression model is developed, which will enable readers to accurately approximate the effective length of the type-A grounding system for realistic values of input features. The trained model in the paper yielded an R 2 value of 0.99998 on the test set. In addition, two simple mathematical formulas are also provided, which produce similar but less accurate results ( R 2 values of 0.989883 and 0.998557, respectively). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
7. Invited discussion paper small-sample distributional properties of nonlinear regression estimators (a geometric approach)
- Author
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Andeej Pizman
- Subjects
Statistics and Probability ,Mathematical optimization ,Heuristic ,Gaussian ,Estimator ,Probability density function ,Conditional probability distribution ,Edgeworth series ,symbols.namesake ,Approximation error ,symbols ,Applied mathematics ,Statistics, Probability and Uncertainty ,Nonlinear regression ,Mathematics - Abstract
The paper is mainly a survey of the topic how to approximate the probability density of the parameter estimator in a nonlinear regression model. A short presentation of the geometry of the model and a heuristic discussion of the model and a heuristic discussion of the “irregularities” of the estimates are given. In the model with Gaussian errors we present the asymptotic normal approximation, the approximationby the second order Edgeworth expansion, a conditional density of BARNDORFF-NIELSEN, and mainly the approximation called “flat” or “saddlepoint” approximation, which will be shown to have several interesting properties. Further, we present the possibility of improving the approximation in some models, the extension of the approximation to some cases of nongaussian errors, and besides the maximum likelihood estimator we consider also the weighted least-squares estimator, with the weights not depending on the error concariance matrix.
- Published
- 1990
8. Maximum Correntropy Criterion-Based UKF for Loosely Coupling INS and UWB in Indoor Localization.
- Author
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Yan Wang, You Lu, Yuqing Zhou, and Zhijian Zhao
- Subjects
INERTIAL navigation systems ,NONLINEAR regression ,COVARIANCE matrices ,NOISE measurement ,KALMAN filtering - Abstract
Indoor positioning is a key technology in today's intelligent environments, and it plays a crucial role in many application areas. This paper proposed an unscented Kalman filter (UKF) based on the maximum correntropy criterion (MCC) instead of the minimummean square error criterion (MMSE). This innovative approach is applied to the loose coupling of the Inertial Navigation System (INS) and Ultra-Wideband (UWB). By introducing the maximum correntropy criterion, the MCCUKF algorithm dynamically adjusts the covariance matrices of the system noise and the measurement noise, thus enhancing its adaptability to diverse environmental localization requirements. Particularly in the presence of non-Gaussian noise, especially heavy-tailed noise, the MCCUKF exhibits superior accuracy and robustness compared to the traditional UKF. The method initially generates an estimate of the predicted state and covariance matrix through the unscented transform (UT) and then recharacterizes the measurement information using a nonlinear regression method at the cost of theMCC. Subsequently, the state and covariance matrices of the filter are updated by employing the unscented transformation on the measurement equations. Moreover, to mitigate the influence of non-line-of-sight (NLOS) errors positioning accuracy, this paper proposes a k-medoid clustering algorithm based on bisection k-means (Bikmeans). This algorithm preprocesses the UWB distance measurements to yield a more precise position estimation. Simulation results demonstrate that MCCUKF is robust to the uncertainty of UWB and realizes stable integration of INS and UWB systems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Do cross-border investors benchmark commercial real estate markets? : Evidence from relative yields and risk premia for a European investment horizon
- Author
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Oertel, Cay, Willwersch, Jonas, and Cajias, Marcelo
- Published
- 2020
- Full Text
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10. Cotton farming industry development and policy finance support for demand estimation in Aksu.
- Author
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Yang, Airong and Xia, Yong
- Subjects
COTTON trade ,AGRICULTURAL industries ,FARM produce prices ,DATA mining ,NONLINEAR regression ,AGRICULTURAL prices ,COTTON growing - Abstract
Using data mining, the purpose of this study is to forecast and analyze the growth of the cotton cultivation industry and the policy financial support demands in the Aksu region. Data mining is a method for maximizing the value of data via the application of numerous algorithms. In contrast to conventional data mining, which adheres to specific algorithms, data mining employs a variety of analysis algorithms to analyze raw data, such as image and panel data, and produce accurate results. In this paper, we propose a data mining method that combines the semantic segmentation algorithm of remote sensing images with various nonlinear regression algorithms to predict the demand for policy-based financial support in a specific region based on a combination of multiple factors, including agricultural crop cultivation area, catastrophe analyses, agricultural price and inflation rates, etc. This paper intends to estimate and analyze actual data pertaining to the cotton cultivation industry in Aksu, and this methodology can further improve the policy-based financial inverse model. The methods presented in this paper can further improve countercyclical regulation of policy finance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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11. Fitting Models to Biological Data Using Linear and Nonlinear Regression: A Practical Guide to Curve Fitting. By Harvey Motulsky and , Arthur Christopoulos. Oxford and New York: Oxford University Press. $65.00 (hardcover); $29.95 (paper). 351 p; ill.; index. ISBN: 0–19–517179–9 (hc); 0–19–517180–2 (pb). 2004
- Author
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Roberto Maass-Moreno
- Subjects
Biological data ,Index (economics) ,Curve fitting ,Applied mathematics ,General Agricultural and Biological Sciences ,Nonlinear regression ,Mathematics - Published
- 2005
12. An effective Q extraction method via deep learning.
- Author
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Li, Fang, Yu, Zhenzhen, and Ma, Jianwei
- Subjects
VERTICAL seismic profiling ,DEEP learning ,QUALITY factor ,NONLINEAR regression - Abstract
The quality factor (Q) is a parameter reflecting the physical properties of reservoirs. Accurate estimation of the quality factor plays an important role in improving the resolution of seismic data. Spectral-ratio method is a widely used traditional method based on the linear least-squares fitting to extract the quality factor, but is sensitive to noise. This is the main reason preventing this method from being widely used. Some supervised deep-learning methods are proposed to extract Q in which the construction of training labels is a key link. The proposed method is based on the spectral-ratio method to create training labels, avoiding errors in generating them. In contrast to the least-squares method, this paper proposes to use a nonlinear regression algorithm based on a fully connected network to fit the spectral logarithmic ratio and frequency. Meanwhile, the empirical equation is applied to constrain prediction results. The proposed method can effectively overcome the influence of noise and improve the accuracy of prediction results. Tests on the synthesized data of vertical seismic profile and common middle profile show that the proposed method has better generalization ability than the spectral-ratio method. Applying the method to the field vertical seismic profile data successfully extracts the quality factor, which can provide effective information for dividing stratigraphic layers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
13. Sound Speed Inversion Based on Multi-Source Ocean Remote Sensing Observations and Machine Learning.
- Author
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Feng, Xiao, Tian, Tian, Zhou, Mingzhang, Sun, Haixin, Li, Dingzhao, Tian, Feng, and Lin, Rongbin
- Subjects
MACHINE learning ,REMOTE sensing ,SPEED of sound ,OCEAN ,NONLINEAR regression ,ORTHOGONAL functions - Abstract
Ocean sound speed is important for underwater acoustic applications, such as communications, navigation and localization, where the assumption of uniformly distributed sound speed profiles (SSPs) is generally used and greatly degrades the performance of underwater acoustic systems. The acquisition of SSPs is necessary for the corrections of the sound ray propagation paths. However, the inversion of SSPs is challenging due to the intricate relations of interrelated physical ocean elements and suffers from the high costs of calculations and hardware deployments. This paper proposes a novel sound speed inversion method based on multi-source ocean remote sensing observations and machine learning, which adapts to large-scale sea regions. Firstly, the datasets of SSPs are generated utilizing the Argo thermohaline profiles and the empirical formulas of the sound speed. Then, the SSPs are analyzed utilizing the empirical orthogonal functions (EOFs) to reduce the dimensions of the feature space as well as the computational load. Considering the nonlinear regression relations of SSPs and the observed datasets, a general framework for sound speed inversion is formulated, which combines the designed machine learning models with the reduced-dimensional feature representations, multi-source ocean remote sensing observations and water temperature data. After being well trained, the proposed machine learning models realize the accurate inversion of the targeted ocean region by inputting the real-time ocean environmental data. The experiments verify the advantages of the proposed method in terms of the accuracy and effectiveness compared with conventional methods. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
14. HIGHLY ROBUST TRAINING OF REGULARIZED RADIAL BASIS FUNCTION NETWORKS.
- Author
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Kalina, Jan, Vidnerova, Petra, and Janacek, Patrik
- Subjects
RADIAL basis functions ,LEAST squares ,NONLINEAR regression ,REGRESSION analysis ,QUANTILE regression ,OUTLIER detection - Abstract
Radial basis function (RBF) networks represent established tools for nonlinear regression modeling with numerous applications in various fields. Because their standard training is vulnerable with respect to the presence of outliers in the data, several robust methods for RBF network training have been proposed recently. This paper is interested in robust regularized RBF networks. A robust inter-quantile version of RBF networks based on trimmed least squares is proposed here. Then, a systematic comparison of robust regularized RBF networks follows, which is evaluated over a set of 405 networks trained using various combinations of robustness and regularization types. The experiments proceed with a particular focus on the effect of variable selection, which is performed by means of a backward procedure, on the optimal number of RBF units. The regularized inter-quantile RBF networks based on trimmed least squares turn out to outperform the competing approaches in the experiments if a highly robust prediction error measure is considered. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. An Improved Method for the Determination of the Reservoir-Gas Specific Gravity for Retrograde Gases (includes associated papers 20006 and 20010 )
- Author
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J.W. Jennings, W.D. McCain, and D.K. Gold
- Subjects
Chemistry ,Strategy and Management ,Energy Engineering and Power Technology ,Separator (oil production) ,Thermodynamics ,Improved method ,Mechanics ,Petroleum reservoir ,Natural gas field ,Fuel Technology ,Exact solutions in general relativity ,Industrial relations ,Nonlinear regression ,Specific gravity ,Retrograde condensation - Abstract
Summary A method is presented that provides an improved estimate of the reservoir-gas specific gravity for retrograde-gas reservoirs from field production information. This method offers several improvements over previous methods. First, a new term has been introduced into the gas-gravity equation in order to emulate the exact solution of the equation. This term, the additional gas production, Gpa, accounts for the gas production from the low-pressure separator and stock tank. Second, a correlation for the vapor equivalent of the primary-separator liquid, Veq, has been improved. And third, Gpa and Veq correlations were developed for both two-stage and three-stage separation systems. These correlations were developed with the flash liberation results from laboratory fluid analyses. The models were fit to the data by nonlinear regression. The estimate of the reservoir-gas specific gravity is significantly improved by incorporating the new Gpa and improved Veq correlations into the gas-gravity equation. Also, the improved Veq correlation, which accounts for the low-pressure separator gas, stock-tank gas, and stock-tank liquid production, can be used to obtain better estimates of oil fluid withdrawal. Introduction The reservoir-gas specific gravity is used by petroleum engineers to gas pseudocritical properties, gas-law deviation factors, and real-gas pseudopressure for bottomhole pressure calculations, deliverability analysis, and reservoir material-balance calculations. The reservoir-gas specific gravity for a retrograde-gas reservoir can be determined by two methods. The first method requires that fluid samples of the primary-separator liquid and gas be obtained from the well, that their respective compositions be determined in the laboratory, and that they then be recombined according to the producing gas/liquid ratio. The second method uses the field production information in the form of a mathematical recombination expression. The laboratory fluid analysis provides the most accurate determination of reservoir-gas specific gravity; however, the field production information can provide a very reliable estimate. The equation for calculating the reservoir-gas specific gravity from production information requires knowledge of separator gas and stock-tank liquid production and the specific gravities of the respective fluids. For a three-stage separation system (consisting of primary and secondary separators and a stock tank), the gas specific gravities and production rates from the primary separator, secondary separator, and stock tank, and the stock-tank liquid gravity, must be known. For a two-stage separation system (consisting of a primary separator and a stock tank), the gas specific gravities and production rates from the primary separator and stock tank, and the stock-tank liquid gravity, must be known. In many cases, only the primary-separator gas production rate and specific gravity, and the stock-tank liquid production rate and gravity, are measured. The gas production from low-pressure separators (the secondary separator and stock tank for a three-stage system, or the stock tank for a two-stage system) is often not measured. Hence, to calculate the reservoir-gas specific gravity with production data, either this production has to be measured or a method to predict these values has to be used. The correlations for additional gas production, Gpa, and the vapor equivalent of the primary-separator liquid, Veq, account for the unknown values needed to calculate the reservoir-gas specific gravity. The Gpa correlation is a new correlation. Previously, the terms represented by Gpa have been assumed negligible. The purpose of the Gpa correlation is to predict the gas production after the primary separator so that this production can be incorporated in the equation for the reservoir-gas specific gravity. The Veq correlation presented here is an improvement of an earlier correlation. Veq accounts for the gas and liquid production after the primary separator. The purpose of the Veq correlation is two-fold; in addition to its use in calculating the reservoir-gas specific gravity, it can be used to calculate the reservoir fluid withdrawal. A correlation for Veq was first proposed by Leshikar. This method is based on Eilerts and Cotton's correlation for condensate gravity and molecular weight and on Beal's correlation for gas solubility. The independent parameters in this method are the primary-separator pressure and API gravity of the stock-tank liquid. Leshikar's correlation underestimates Veq at high primary-separator pressures and stock-tank liquid gravities because Beal's correlation was developed with black-oil data and not retrograde-gas data. Additionally, liquids with high molecular weights in addition to retrograde gases were used in the development of Eilerts' correlation. Leshikar's correlation for Veq results in an average absolute error of 16% when compared with the gas samples used in this study. A different approach was taken in the development of an improved Veq correlation. Veq is the equivalent volume of gas represented by the primary-separator liquid, Veq can be defined in terms of the production after primary separation takes place--that is, the secondary-separator gas/liquid ratio (for a three-stage system), the stock-tank gas/liquid ratio, and the gravity and molecular weight of the stock-tank liquid. Similarly, Gpa can be defined in terms of the secondary-separator (for a three-stage system)and stock-tank gas/liquid ratios and gas specific gravities. These production values were generated with a flash liberation algorithm with different conditions of separator pressures and temperatures for 234 retrograde-gas samples collected worldwide. Both two-stage and three-stage separation systems were simulated. Non-linear regression was used to fit appropriate models to the data. The independent parameters in the models are the primary-separator pressure and temperature, the specific gravity of the primary-separator gas, the gravity of the stock-tank liquid, the secondary-separator temperature (for a three-stage separation system), and the stock-tank temperature. The purpose of this paper is to present the new Gpa and improved Veq correlations for both two-stage and three-stage separation systems and to show how to calculate the reservoir-gas specific gravity and reservoir fluid withdrawal with these correlations. Theory The specific gravity of the reservoir gas, gamma g, for a three-stage flash liberation process can be calculated with the recombination expression (1) The recombination expression for a two-stage separation system is (2) JPT P. 747^
- Published
- 1989
16. Drying kinetics of ‘gueroba’ (Syagrus oleracea) fruit pulp
- Author
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Daniel Emanuel Cabral de Oliveira, Osvaldo Resende, Weder N. Ferreira, Ana P. P. Jorge, and Lígia C. de M. Silva
- Subjects
0106 biological sciences ,Environmental Engineering ,Coefficient of determination ,Materials science ,Agriculture (General) ,Kinetics ,Activation energy ,engineering.material ,Thermal diffusivity ,01 natural sciences ,S1-972 ,Syagrus oleracea ,AIC ,BIC ,Water content ,Pulp (paper) ,mathematical modeling ,04 agricultural and veterinary sciences ,Pulp and paper industry ,Midilli ,040103 agronomy & agriculture ,engineering ,0401 agriculture, forestry, and fisheries ,Agronomy and Crop Science ,Nonlinear regression ,010606 plant biology & botany - Abstract
The ‘Gueroba’ fruit can be used to produce flours with potential for the development of new products from the ‘Cerrado’ socio-biodiversity. The objective was to estimate the drying kinetics and determine the effective diffusion coefficient and activation energy for the pulp of ‘gueroba’ fruits subjected to different drying temperatures. ‘Gueroba’ fruits were manually pulped, removing the mesocarp with the epicarp, and this material was identified as the pulp. The material was subjected to oven drying at temperatures of 40, 50, 60 and 70 °C. Nonlinear regression models were fitted to the experimental data. The most adequate model was selected through the coefficient of determination, mean relative and estimated errors, Chi-square test, AIC and BIC. As the drying temperature increases, the processing time to achieve the same moisture content decreases, due to the increase in water diffusivity inside the product. The Midilli model showed the best fit to the experimental data obtained. The effective diffusion coefficients of the pulp of ‘gueroba’ fruits showed magnitudes between 3.11 x 10-9 to 5.84 x 10-9 m2 s-1 for temperatures from 40 to 70 °C. The activation energy of the process was 18.34 kJ mol-1.
- Published
- 2020
17. Exponential excitations for effective identification of Wiener system.
- Author
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Maik, Gabriel, Mzyk, Grzegorz, and Wachel, Paweł
- Subjects
NONLINEAR estimation ,IMPULSE response ,NONLINEAR regression ,SYSTEM identification ,FIR - Abstract
The paper considers the problem of nonparametric estimation of nonlinear characteristic in the FIR Wiener system. Methods proposed so far have suffered from the so-called 'curse of dimensionality' and their practical applications have been limited to the very short impulse responses of the linear component. In the proposed approach, the class of (stochastically initialised) repeated exponential input excitations is introduced, and a modified kernel-based estimator is presented. It is shown that the rate of convergence to the genuine system characteristic is significantly improved and does not depend on the length of the impulse response of the linear dynamic block. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Machine learning method predicting thermal performance of conformal cooling systems.
- Author
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Zhao, Zhiqiang
- Subjects
COOLING systems ,NONLINEAR regression ,REGRESSION analysis ,THERMAL efficiency ,MACHINE learning - Abstract
The incorporation of conformal cooling systems has significantly enhanced the efficiency and quality of injection molding process. While several automated methods have been developed for creating conformal cooling channels in injection molds, the current optimization process for conformal cooling design parameters is hindered by labor-intensive iterative thermal simulation processes and the substantial reliance on empirical human knowledge. This paper presents an innovative machine learning method to assess the thermal performance of conformal cooling systems by employing a combination of a non-linear regression model and a neural network. By employing a logarithmic regression model describing the temperature graph and a neural network predicting the coefficients of the logarithmic regression model, the thermal performance of specified conformal cooling systems can be assessed and predicted precisely. This methodology empowers designers to evaluate the thermal efficiency of conformal cooling systems efficiently and effectively to further optimize the conformal cooling design parameters without relying on tedious manual thermal and fluid simulation processes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Machine Learning Techniques for Blind Beam Alignment in mmWave Massive MIMO.
- Author
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Ktari, Aymen, Ghauch, Hadi, and Rekaya-Ben Othman, Ghaya
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MACHINE learning ,MATRIX decomposition ,LOW-rank matrices ,NONLINEAR regression ,ANTENNAS (Electronics) - Abstract
This paper proposes methods for Machine Learning (ML)-based Beam Alignment (BA), using low-complexity ML models, and achieves a small pilot overhead. We assume a single-user massive mmWave MIMO, Uplink, using a fully analog architecture. Assuming large-dimension codebooks of possible beam patterns at U E and B S , this data-driven and model-based approach aims to partially and blindly sound a small subset of beams from these codebooks. The proposed BA is blind (no CSI), based on Received Signal Energies (RSEs), and circumvents the need for exhaustively sounding all possible beams. A sub-sampled subset of beams is then used to train several ML models such as low-rank Matrix Factorization (MF), non-negative MF (NMF), and shallow Multi-Layer Perceptron (MLP). We provide an extensive mathematical description of these models and the algorithms for each of them. Our extensive numerical results show that, by sounding only 10 % of the beams from the U E and B S codebooks, the proposed ML tools are able to accurately predict the non-sounded beams through multiple transmitted power regimes. This observation holds as the codebook sizes at U E and B S vary from 128 × 128 to 1024 × 1024 . [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. Linear and Non-Linear Regression Methods for the Prediction of Lower Facial Measurements from Upper Facial Measurements.
- Author
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Terblanche, Jacques, Merwe, Johan van der, and Laubscher, Ryno
- Subjects
NONLINEAR regression ,ORTHOGNATHIC surgery ,MEASUREMENT errors ,RANDOM forest algorithms ,PREDICTION models - Abstract
Accurate assessment and prediction of mandible shape are fundamental prerequisites for successful orthognathic surgery. Previous studies have predominantly used linear models to predict lower facial structures from facial landmarks or measurements; the prediction errors for this did not meet clinical tolerances. This paper compared non-linear models, namely a Multilayer Perceptron (MLP), a Mixture Density Network (MDN), and a Random Forest (RF) model, with a Linear Regression (LR) model in an attempt to improve prediction accuracy. The models were fitted to a dataset of measurements from 155 subjects. The test-set mean absolute errors (MAEs) for distance-based target features for the MLP, MDN, RF, and LR models were respectively 2.77 mm, 2.79 mm, 2.95 mm, and 2.91 mm. Similarly, the MAEs for angle-based features were 3.09°, 3.11°, 3.07°, and 3.12° for each model, respectively. All models had comparable performance, with neural network-based methods having marginally fewer errors outside of clinical specifications. Therefore, while non-linear methods have the potential to outperform linear models in the prediction of lower facial measurements from upper facial measurements, current results suggest that further refinement is necessary prior to clinical use. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. An improved regression‐based perturb and observation global maximum power point tracker methods.
- Author
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Gundogdu, Hasan, Demirci, Alpaslan, Tercan, Said Mirza, and Durusu, Ali
- Subjects
ELECTRIC power ,MAXIMUM power point trackers ,RENEWABLE natural resources ,POWER electronics ,POWER semiconductors ,NONLINEAR regression - Abstract
Solar photovoltaic energy is a vital renewable resource because it is clean, endless, and pollution‐free. Due to the fast growth of the semiconductor and power electronics sectors, photovoltaic (PV) technologies are climbing significant attention in modern electrical power applications. Operating PV energy conversion systems at the maximum power point is essential for getting the maximum power output and raising efficiency. This paper proposes a regression‐based Perturb and Observe method to quickly find a global maximum power point, avoiding being stuck in local maxima, likewise analytical and metaheuristic methods. The improved control focuses on the narrowed search areas by linear and non‐linear regression analyses using the generated PV model on a flexible Python environment. Furthermore, the method's accuracy is validated in real time under variable temperatures, irradiations, and loads. This method was proven with a hardware implementation. The proposed method is more than 98% accurate and can withstand long‐term modelling. The suggested regression‐based perturbation and observation method provided a short learning time and easy implementation. Additionally, the dynamic recorded results can be visualized for researchers to utilize efficiently. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Gas Free Dissipation Characteristics Analysis and Safety Repair Time Determination of Buried Pipeline Leakage Based on CFD.
- Author
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Bu, Fanxi, He, Yuheng, Liu, Ming, Lv, Zhuoran, Bai, Jinyu, Leng, Chunmiao, and Wang, Zhihua
- Subjects
GAS leakage ,NATURAL gas transportation ,NONLINEAR regression ,LEAST squares ,GAS distribution - Abstract
Buried pipelines, as the most common method of natural gas transportation, are prone to pipeline leakage accidents and are difficult to detect due to their harsh and concealed environment. This paper focused on the problem regarding the free dissipation of residual gas in buried gas pipelines and soil after closing the gas supply end valve after a period of leakage by numerical simulation. A multiple non-linear regression model was established based on the least squares method and multiple regression theory, and MATLAB 2016b mathematical calculation software was used to solve the problem. The research results indicated that compared to the gas leakage diffusion stage, the pressure and velocity distribution during the free dissipation stage were significantly reduced. The increase in leakage time, pipeline pressure, leakage size, and pipeline burial depth led to a large accumulation of natural gas, which increased the concentration and distribution range of gas on the same free dissipation stage monitoring line. A prediction model for natural gas concentration in the free dissipation stage was established with an average error of 7.88%. A calculation model for the safety repair time of buried gas pipeline leakage accidents was further derived to determine the safety repair time of leakage accidents. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Performance analysis of classifiers in detection of CVD using PPG signals.
- Author
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Rajaguru, Harikumar, Shankar, M. Gowri, Nanthakumar, S. P., and Murugan, I. Arul
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CARDIOVASCULAR system ,GAUSSIAN mixture models ,NONLINEAR regression ,BLOOD vessels ,ERROR rates ,HEART ,TOES - Abstract
To measure the circulatory system of skin using infrared light, PPG is extensively utilized. PPG has a lot of innate focal points like affordability, non-prominent in nature and goes probably as a versatile demonstrative gadget. It helps in the assessment of circulatory strain, oxygen inundation levels, heart yield and for administering distinctive other autonomic components of the body. For the amazing screening of different pathologies, PPG fills in as a huge promising framework. The improvement of blood in the vessel which spreads from the heart to the toes and fingertips is reflected by the PPG signals. In this paper, PPG signals are utilized for a singular patient who is encountering cardio vascular issues. For the PPG signals, the Firefly clusters and Dragonfly selector algorithms is utilized. In this study an in depth analysis of classifiers in detection of cardiovascular diseases (CVD) is done with the help of capnobase database. The following classifiers are used in this paper linear regression, Nonlinear Regression, Logistic regression, Bayesian linear discriminant classifier (BDLC) and Gaussian Mixture Model (GMM) and firefly. The plan and execution of a PPG are very economical and have a simple support. It is also used for the peripheral blood fluorescent and venous filling time. Results show that the Linear Regression classifier exceeds the other five classifiers in terms of accuracy (65.85%), F1 score (68.18%), MCC (0.316), Jaccard metric (51.72%), and error rate (34.15%). [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
24. P‐6.1: Research about LCD Flicker Testing Methods and Conversion Relationship.
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Chao, Yu, Xiny, Cheng, and Changlin, Leng
- Subjects
TEST methods ,REGRESSION analysis ,NONLINEAR regression ,MATHEMATICAL statistics ,LIQUID crystal displays ,TESTING equipment - Abstract
As a common technology product in life, display screen has been deeply embedded in various fields, and the display performance is the key indicator to determine the quality of display products. The evaluation of screen flicker is one of the key control parameters to evaluate the optical performance of the screen. As the paper introduced, commonly there are two methods of testing flicker: FMA method and JEITA method. This paper makes a research about the above two evaluation methods in time and frequency domain. Particularly, by using nonlinear regression of the mathematical statistics, this paper deduces the mathematical relationship of the two methods for the evaluating in the normal data field. Also, this paper gives accurate conversion formula and the precision analysis. By using the empirical formula, the complexity of existing test equipment can be simplified, the cost and test time can be saved greatly. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
25. A hybridmodel formetro passengers flow prediction.
- Author
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Yuqing Sun and Kaili Liao
- Subjects
NONLINEAR regression ,WAVELET transforms ,SEARCH algorithms ,LONG-term memory ,TRAFFIC flow ,FORECASTING - Abstract
In this paper, a novel ensemble learning model named EWT-EnsemLSTM-SSA, which assembles long short-term memory (LSTM), support vector regression (SVR), and sparrow search algorithm (SSA), is a proposed to deal with long term metro passenger flow volume prediction, which is an essential content of traffic flow prediction problems. Firstly, the empirical wavelet transform (EWT) method is introduced to decompose the original dataset into five wavelet time-sequence data for further prediction. Then, a cluster of LSTMs with diverse hidden layers and neuron counts are employed to explore and exploit the implicit information of the EWT-decomposed signals. Next, the output of LSTMs is aggregated into a nonlinear regression method SVR. Lastly, SSA is utilized to optimize the SVR automatically. The proposed EWT-EnsemLSTM-SSA model is applied in three case studies, using the data collected from the passengers' amount in the Minneapolis, America metro, divided into one hour in one day. Experiment results, which compare the proposed EnsemLSTM-SSA model with five conventional time series forecasting models, show that the proposed model can achieve a better performance than the traditional prediction algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
26. Multivariate nonlinear regression analysis of hydraulic fracturing parameters based on hybrid FEM–DEM.
- Author
-
Li, Yang and Lan, Tianxiang
- Subjects
NONLINEAR regression ,HYDRAULIC fracturing ,POISSON'S ratio ,REGRESSION analysis ,NONLINEAR analysis - Abstract
Purpose: This paper aims to employ a multivariate nonlinear regression analysis to establish a predictive model for the final fracture area, while accounting for the impact of individual parameters. Design/methodology/approach: This analysis is based on the numerical simulation data obtained, using the hybrid finite element–discrete element (FE–DE) method. The forecasting model was compared with the numerical results and the accuracy of the model was evaluated by the root mean square (RMS) and the RMS error, the mean absolute error and the mean absolute percentage error. Findings: The multivariate nonlinear regression model can accurately predict the nonlinear relationships between injection rate, leakoff coefficient, elastic modulus, permeability, Poisson's ratio, pore pressure and final fracture area. The regression equations obtained from the Newton iteration of the least squares method are strong in terms of the fit to the six sensitive parameters, and the model follow essentially the same trend with the numerical simulation data, with no systematic divergence detected. Least absolutely deviation has a significantly weaker performance than the least squares method. The percentage contribution of sensitive parameters to the final fracture area is available from the simulation results and forecast model. Injection rate, leakoff coefficient, permeability, elastic modulus, pore pressure and Poisson's ratio contribute 43.4%, −19.4%, 24.8%, −19.2%, −21.3% and 10.1% to the final fracture area, respectively, as they increased gradually. In summary, (1) the fluid injection rate has the greatest influence on the final fracture area. (2)The multivariate nonlinear regression equation was optimally obtained after 59 iterations of the least squares-based Newton method and 27 derivative evaluations, with a decidability coefficient R2 = 0.711 representing the model reliability and the regression equations fit the four parameters of leakoff coefficient, permeability, elastic modulus and pore pressure very satisfactorily. The models follow essentially the identical trend with the numerical simulation data and there is no systematic divergence. The least absolute deviation has a significantly weaker fit than the least squares method. (3)The nonlinear forecasting model of physical parameters of hydraulic fracturing established in this paper can be applied as a standard for optimizing the fracturing strategy and predicting the fracturing efficiency in situ field and numerical simulation. Its effectiveness can be trained and optimized by experimental and simulation data, and taking into account more basic data and establishing regression equations, containing more fracturing parameters will be the further research interests. Originality/value: The nonlinear forecasting model of physical parameters of hydraulic fracturing established in this paper can be applied as a standard for optimizing the fracturing strategy and predicting the fracturing efficiency in situ field and numerical simulation. Its effectiveness can be trained and optimized by experimental and simulation data, and taking into account more basic data and establishing regression equations, containing more fracturing parameters will be the further research interests. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
27. Microseismic Data-Direct Velocity Modeling Method Based on a Modified Attention U-Net Architecture.
- Author
-
Zhou, Yixiu, Han, Liguo, Zhang, Pan, Zeng, Jingwen, Shang, Xujia, and Huang, Wensha
- Subjects
VELOCITY ,NONLINEAR regression ,DEEP learning ,NONLINEAR equations ,ANTICLINES ,GEOLOGICAL modeling - Abstract
In microseismic monitoring, the reconstruction of a reliable velocity model is essential for precise seismic source localization and subsurface imaging. However, traditional methods for microseismic velocity inversion face challenges in terms of precision and computational efficiency. In this paper, we use deep learning (DL) algorithms to achieve precise and efficient real-time microseismic velocity modeling, which holds significant importance for ensuring engineering safety and preventing geological disasters in microseismic monitoring. Given that this task was approached as a non-linear regression problem, we adopted and modified the Attention U-Net network for inversion. Depending on the degree of coupling among microseismic events, we trained the network using both single-event and multi-event simulation records as feature datasets. This approach can achieve velocity modeling when dealing with inseparable microseismic records. Numerical tests demonstrate that the Attention U-Net can automatically uncover latent features and patterns between microseismic records and velocity models. It performs effectively in real time and achieves high precision in velocity modeling for Tilted Transverse Isotropy (TTI) velocity structures such as anticlines, synclines, and anomalous velocity models. Furthermore, it can provide reliable initial models for traditional methods. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. Stochastic Time Complexity Surfaces of Computing Node.
- Author
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Borisov, Andrey and Ivanov, Alexey
- Subjects
TIME complexity ,PARAMETER identification ,PROBABILITY theory ,VECTOR valued functions ,DATABASES - Abstract
The paper is devoted to the formal description of the running time of the user task on some virtual nodes in the computing network. Based on the probability theory framework, this time represents a random value with a finite mean and variance. For any class of user task, these moments are the functions of the node resources, task numerical characteristics, and the parameters of the current node state. These functions of the vector arguments can be treated as some surfaces in the multidimensional Euclidean spaces, so the proposed models are called the stochastic time complexity surfaces. The paper also presents a class of functions suitable for the description of both the mean and variance. They contain unknown parameters which should be estimated. The article includes the statement of the parameter identification problem given the statistical results of the node stress testing, recommendations concerning the test planning, and preprocessing of the raw experiment data. To illustrate the performance of the proposed model, the authors design it for an actual database application—the prototype of the passengers' personal data anonymization system. Its application functions are classified into two user task classes: the data anonymization procedures and fulfillment of the statistical queries. The authors identify the stochastic time complexity surfaces for both task types. The additional testing experiments confirm the high performance of the suggested model and its applicability to the solution of the practical providers' problems. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Nonlinear regression analysis and response surface modeling of Cr (VI) removal from synthetic wastewater by an agro-waste Cocos Nucifera: Box-Behnken Design (BBD)
- Author
-
Krishna Murari Prasad Singh, R. K. Tiwary, Mahendra Yadav, and Binu Kumari
- Subjects
0106 biological sciences ,Materials science ,Shell (structure) ,Plant Science ,Process variable ,010501 environmental sciences ,Pulp and paper industry ,01 natural sciences ,Pollution ,Box–Behnken design ,Adsorption ,Cocos nucifera ,Wastewater ,Environmental Chemistry ,Coir ,Nonlinear regression ,010606 plant biology & botany ,0105 earth and related environmental sciences - Abstract
In this study mixture of coconut shell and coir was used for Cr (VI) removal from synthetic wastewater and statistical tool Response Surface Modeling (RSM) was applied to optimize process parameter...
- Published
- 2020
30. Application Conditions of Binomial Regression Method for Reserves Evaluation of Geopressured Gas Reservoirs
- Author
-
Zhu, Song-bai, Sun, He-dong, Xian, Bo, Gan, Nian-ping, Shao, Jian-bo, Wu, Dong-hui, Wang, Yan-li, Dong, Chen, Liu, Xiao-dong, Wu, Wei, Series Editor, and Lin, Jia'en, editor
- Published
- 2024
- Full Text
- View/download PDF
31. Editorial.
- Author
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Upadhyaya, Lalit Mohan
- Subjects
DIOPHANTINE equations ,NONLINEAR regression - Published
- 2023
32. Production of tomato cultivated in different nutritive solutions.
- Author
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Antônio Turchiello, Marcos, Dal'Col Lúcio, Alessandro, Godoi, Rodrigo, de Paula Ribeiro, Ana Lúcia, and Fontana, André
- Subjects
SPRING ,AUTUMN ,NONLINEAR regression ,TOMATOES ,ANALYSIS of variance ,PLANT nutrition ,PLANT productivity ,PLASTIC bags ,FRUIT - Abstract
The objective this paper is determine the highest performance of fresh mass and number of fruits in tomato crops using different nutrient solution. An absolute hybrid with a semi-determined growth was used. It was grown in a protected environment using a fertigated substrate inside plastic bags containing ten liters of solution. The experiment was completely randomized with four levels of fertilization and five replications. Two experiments were carried out in two cultivation cycles (spring 2018 and autumn 2019) by performing an analysis of variance and Scott & Knott test and estimating the parameters of nonlinear logistic model and its critical points for both variables in each treatment. The mean fruit mass per plant was 3.70 kg for the spring experiment and 3.80 kg for the autumn experiment. The mean number of fruits per plant was 10.50 and 10.70 fruits for spring and autumn, respectively. There are significant differences between the treatments KO46, KO45 and KO56 compared to KO69 for fruit mass in the autumn experiment. For the other variables and cultivation cycles, the treatments did not show statistical differences. The logistic growth model fitted the weight and number of tomato fruits according to days after transplanting the seedlings and evidenced production cycle data, highlighting the main differences between the nutrient solutions. The nutritional solutions KO46, KO45 and KO56 are recommended for growing Gaúcho tomatoes in substrate. The nutrient solution KO56 has the best performance because it has a higher K availability, meets the balance of loads and antagonism between nutrients, provides equal response of means mass and number of fruits, and has a lower N:K ratio and balance of K over Ca and Mg, thus favoring fruit production, precocity, and development. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. Measuring fuel consumption in vehicle routing: new estimation models using supervised learning.
- Author
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Heni, Hamza, Arona Diop, S., Renaud, Jacques, and Coelho, Leandro C.
- Subjects
ENERGY consumption ,SUPERVISED learning ,EMISSIONS (Air pollution) ,CONSUMPTION (Economics) ,NONLINEAR regression ,SUPPORT vector machines - Abstract
In this paper, we propose and assess the accuracy of new fuel consumption estimation models for vehicle routing. Based on real-world data consisting of instantaneous fuel consumption, time-varying speeds observations, and high-frequency traffic, we propose effective methods to estimate fuel consumption. By carrying out nonlinear regression analysis using supervised learning methods, namely Neural Networks, Support Vector Machines, Conditional Inference Trees, and Gradient Boosting Machines, we develop new models that provide better prediction accuracy than classical models. We correctly estimate consumption for time-dependent point-to-point routing under realistic conditions. Our methods provide a more precise alternative to classical regression methods used in the literature, as they are developed for a specific situation. Extensive computational experiments under realistic conditions show the effectiveness of the proposed machine learning consumption models, clearly outperforming macroscopic and microscopic consumption models such as the Comprehensive Modal Emissions Model (CMEM) and the Methodology for Estimating air pollutant Emissions from Transport (MEET). Based on sensitivity analyses we show that MEET underestimates real-world consumption by 24.94% and CMEM leads to an overestimation of consumption by 7.57% with optimised parameters. Our best machine learning model (Gradient Boosting Machines) exhibited superior estimation accuracy with a gap of only 1.70%. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Prediction of biogas production rate from anaerobic hybrid reactor by artificial neural network and nonlinear regressions models
- Author
-
Yavuz Demirci and Fatih Tufaner
- Subjects
Economics and Econometrics ,Suspended solids ,Environmental Engineering ,Hydraulic retention time ,020209 energy ,02 engineering and technology ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,Pulp and paper industry ,01 natural sciences ,General Business, Management and Accounting ,Biogas ,Volatile suspended solids ,0202 electrical engineering, electronic engineering, information engineering ,Environmental Chemistry ,Hybrid reactor ,Environmental science ,Effluent ,Nonlinear regression ,0105 earth and related environmental sciences ,Total suspended solids - Abstract
In the present study, a three-layer artificial neural network (ANN) and nonlinear regression models were developed to predict the performance of biogas production from the anaerobic hybrid reactor (AHR). Firstly, the performance of an AHR which is filled with perlite (2.38–4.36 mm) at fill rates of 1/3, 1/4 and 1/5 for the treatment of synthetic wastewater was investigated at a loading rate of 5, 7.5, 10, 12.5 and 15 kg COD m−3 day with 12, 24, 36 and 48 h of hydraulic retention time (HRT) under mesophilic conditions (37 ± 1 °C). In this study, experimental data were used to estimate the biogas production rate with models produced using both ANNs and nonlinear regression methods. Moreover, ten related variables, such as reactor fill ratio, influent pH, effluent pH, influent alkalinity, effluent alkalinity, organic loading rate, effluent chemical oxygen demand, effluent total suspended solids, effluent suspended solids and effluent volatile suspended solids, were selected as inputs of the model. Finally, ANN and nonlinear regression models describing the biogas production rate were developed. The R2, IA, FA2, RMSE, MB for ANNs and nonlinear regression models were found to be 0.9852 and 0.9878, 0.9956 and 0.9945, 0.9973 and 0.9254, 217.4 and 332, 36 and 222, respectively. The statistical quality of ANNs and nonlinear regression models were found to be significant due to its high correlation between experimental and simulated biogas values. The ANN model generally showed greater potential in determining the relationship between input data and the biogas production rate according to statistical parameters (except R2 and R). The results showed that the proposed ANNs and nonlinear regression models performed well in predicting the biogas production rate of AHR on behalf of avoiding economic and environmental sustainability problems.
- Published
- 2020
35. Proposed Equations for HCM-6 Passenger Car Equivalent Values.
- Author
-
Hurtado-Beltran, Antonio and Rilett, Laurence R.
- Subjects
HIGHWAY capacity ,NONLINEAR regression ,REGRESSION analysis ,PASSENGERS ,AUTOMOBILES ,EXPRESS highways - Abstract
In the current version of the Highway Capacity Manual (HCM-6), the equal capacity passenger car equivalency (EC-PCE) method is used to account for the effect of trucks for capacity analyses. The EC-PCEs for freeway segments were estimated using a microsimulationbased methodology where a nonlinear regression model (NLRM) with 15 model parameters was used to develop capacity adjustment factor (CAF) models using the microsimulation data as input. The objective of this paper is to introduce a simpler nonlinear regression model with 6 model parameters that can be used for the estimation of CAF values and EC-PCE values for freeway and multilane highway segments. It was found that the proposed model can readily substitute the original model with little loss in fidelity. The CAF formulae developed in this paper can be used to calculate EC-PCE values directly, obviating the need for the HCM-6 EC-PCE tables. Equally important, the simpler models provide the user with a better understanding of the trade-offs between capacity, CAF, and EC-PCE values and the parameters that affect them. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
36. Development of a Land Price Model for a Medium Sized Indian City.
- Author
-
Kumar, V. S. Sanjay, Yoonus, Shabana, and Anjaneyulu, M. V. L. R.
- Subjects
CENTRAL business districts ,REAL property sales & prices ,GEOGRAPHIC information systems ,NONLINEAR regression ,LAND use - Abstract
Land price plays a crucial role in the development of a region, which serves as an indicator of the features of a property. The primary goal of this paper is to explore the relationship between land price and various geographical and accessibility parameters and thereby arrive at a model to predict the land price. Based on literature surveys, the parameters that influence land price are identified further through which data collection from primary surveys, the creation of a road network map, a geographic information system (GIS) analysis to determine the distance to the central business district (CBD), measurement of road density and access road width, assessment of employment opportunities through establishment surveys, and identification of various land use parcels in the study region are accomplished. The land prices are collected from recently sold parcels in each of the zones in the study region. A negative and significant correlation is observed between land price and distance to the CBD. Positive correlations are observed between land price and other factors considered, such as road density, availability of educational facilities, employment opportunities, and the extent of commercial and residential land use areas. A non-linear regression model is developed that can predict land price depending on the significant parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Airborne Radar Space–Time Adaptive Processing Algorithm Based on Dictionary and Clutter Power Spectrum Correction.
- Author
-
Gao, Zhiqi, Deng, Wei, Huang, Pingping, Xu, Wei, and Tan, Weixian
- Subjects
RADAR in aeronautics ,CLUTTER (Radar) ,ENCYCLOPEDIAS & dictionaries ,POWER spectra ,MACHINE learning ,NONLINEAR regression - Abstract
Sparse recovery space–time adaptive processing (SR-STAP) technology improves the moving target detection performance of airborne radar. However, the sparse recovery method with a fixed dictionary usually leads to an off-grid effect. This paper proposes a STAP algorithm for airborne radar based on dictionary and clutter power spectrum joint correction (DCPSJC-STAP). The algorithm first performs nonlinear regression in a non-stationary clutter environment with unknown yaw angles, and it corrects the corresponding dictionary for each snapshot by updating the clutter ridge parameters. Then, the corrected dictionary is combined with the sparse Bayesian learning algorithm to iteratively update the required hyperparameters, which are used to correct the clutter power spectrum and estimate the clutter covariance matrix. The proposed algorithm can effectively overcome the off-grid effect and improve the moving target detection performance of airborne radar in actual complex clutter environments. Simulation experiments verified the effectiveness of this algorithm in improving clutter estimation accuracy and moving target detection performance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Spatial–Temporal Analysis-Based Video Quality Assessment: A Two-Stream Convolutional Network Approach.
- Author
-
He, Jianghui, Wang, Zhe, Liu, Yi, and Song, Yang
- Subjects
CONVOLUTIONAL neural networks ,NONLINEAR regression ,FEATURE extraction - Abstract
In system processing, video inevitably suffers from distortion, which leads to quality degradation and affects the user experience. Therefore, it is of great importance to design an accurate and effective objective video quality assessment (VQA) method. In this paper, by considering the multi-dimensional characteristics for video and visual perceptual mechanism, a two-stream convolutional network for VQA is proposed based on spatial–temporal analysis, named TSCNN-VQA. Specifically, for feature extraction, TSCNN-VQA first extracts spatial and temporal features by two different convolutional neural network branches, respectively. After that, the spatial–temporal joint feature fusion is constructed to obtain the joint spatial–temporal features. Meanwhile, the TSCNN-VQA also integrates an attention module to guarantee that the process conforms to the mechanism that the visual system perceives video information. Finally, the overall quality is obtained by non-linear regression. The experimental results in both the LIVE and CSIQ VQA datasets show that the performance indicators obtained by TSCNN-VQA are higher than those of existing VQA methods, which demonstrates that TSCNN-VQA can accurately evaluate video quality and has better consistency with the human visual system. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Forecast of sales of selected food products in retail using Fourier series analysis and non-linear regression.
- Author
-
Kačmáry, Peter, Bindzár, Peter, Kovalčík, Jakub, and Ondov, Marek
- Subjects
FOURIER analysis ,REGRESSION analysis ,NONLINEAR regression ,NONLINEAR analysis ,SALES forecasting ,FORECASTING ,FOURIER series - Abstract
Purpose: The purpose of this paper is to apply and verify Fourier series analysis in combination with non-linear regression as a tool of forecasting and planning of inputs in the logistics process of a retail chain store. Design/methodology/approach: For many popular products, a significant effect of seasonality of sales is expected; therefore, the method of Fourier series was chosen as one of the main forecast calculation techniques. However, the use of this method directly for forecasting sales has a limitation in the form of a complete reconstruction of the shape of the curve from of the given monitored time. Thus, the forecast is based only on the significant harmonic components from the Fourier series analysis that will participate in forecast forming. In addition, to respect the trend of series, the results of Fourier series analysis are combined with the non-linear regression. Findings: The results showed that the number of significant harmonic components from the Fourier series analysis is suitable to reflect the future behaviour of the sale in standard market conditions. Forecasting of the sale and accurate purchase planning of goods has a positive effect on reducing the waste of unsold products after their shelf and on increasing of a customer satisfaction. Research limitations/implications: This study has an application in a certain period of time (relatively calm behaviour of the food market) and only for a certain region. Therefore, it is not possible to generalize these results as the behaviour of consumers, e.g. within the state. It will also be interesting to monitor and forecast sales of other food items. Practical implications: This provides a practical and relatively simple tool for implementing or improving the process of forecasting seasonally dependent products in the food industry. Originality/value: This study shows the possibility of forecast that is based on adding the significant harmonic components from the Fourier series analysis to form forecast with the non-linear regression. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Uncertain logistic regression models.
- Author
-
Jinling Gao and Zengtai Gong
- Subjects
REGRESSION analysis ,NONLINEAR regression ,LOGISTIC regression analysis ,ECONOMIC forecasting ,NONLINEAR analysis ,DATA mining - Abstract
Logistic regression is a generalized nonlinear regression analysis model and is often used for data mining, automatic disease diagnosis, economic prediction, and other fields. In this paper, we first aimed to introduce the concept of uncertain logistic regression based on the uncertainty theory, as well as investigating the likelihood function in the sense of uncertain measure to represent the likelihood of unknown parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Forecasting Oil Prices with Non-Linear Dynamic Regression Modeling.
- Author
-
Moreno, Pedro, Figuerola-Ferretti, Isabel, and Muñoz, Antonio
- Subjects
NONLINEAR regression ,REGRESSION analysis ,PETROLEUM sales & prices ,MACHINE learning ,TIME-based pricing - Abstract
The recent energy crisis has renewed interest in forecasting crude oil prices. This paper focuses on identifying the main drivers determining the evolution of crude oil prices and proposes a statistical learning forecasting algorithm based on regression analysis that can be used to generate future oil price scenarios. A combination of a generalized additive model with a linear transfer function with ARIMA noise is used to capture the existence of combinations of non-linear and linear relationships between selected input variables and the crude oil price. The results demonstrate that the physical market balance or fundamental is the most important metric in explaining the evolution of oil prices. The effect of the trading activity and volatility variables are significant under abnormal market conditions. We show that forecast accuracy under the proposed model supersedes benchmark specifications, including the futures prices and analysts' forecasts. Four oil price scenarios are considered for expository purposes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. The resilience of German regions facing the crisis in 2008/2009: the effects of innovation, specialisation, qualifications and sectoral structure.
- Author
-
Celebioglu, Fatih and Brenner, Thomas
- Subjects
QUANTILE regression ,SERVICE industries ,GREAT Recession, 2008-2013 ,ABSTRACTING & indexing services ,NONLINEAR regression ,ECONOMIC recovery - Abstract
Purpose: The purpose of this paper is to explain the effects of innovation, specialisation, qualifications and sectoral structure on the resilience of German regions (municipal level) facing the Great Recession in 2008/2009. Design/methodology/approach: To calculate the effects of various variables on the resilience of German regions against the Great Recession, the authors use quantile regressions. To measure resilience, the authors create a number of indexes representing different parts of the economy: resistance performance index, recovery performance index, shift-share resistance index, shift-share recovery index, manufacturing resistance index, manufacturing recovery index, service resistance index and service recovery index. Findings: The results of this study confirm that locations with employment growth before the crisis and with a good industry structure show better employment dynamics during and after the crisis. The authors find evidence for positive relationship between innovativeness, qualification, the share of the service sector, specialisation and resistance. The authors obtain positive results for related variety and both resistance and recovery. The share of the manufacturing sector only shows a positive relationship with recovery. Originality/value: The authors expand the existing literature in three aspects: First, instead of using regions as observation units, the authors conduct the analyses on the basis of municipalities and their surroundings. By doing so, the authors reduce the modifiable area unit problem because the authors do not rely on regions defined for administrative reasons. Second, the authors apply quantile regressions to detect nonlinear effects. Third, in addition to the resilience of the whole economy, the authors also study the resilience of the manufacturing and service sectors separately and examine the resilience of the local shift effect. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Soft Computing-Based Models for Estimating the Ultimate Bearing Capacity of an Annular Footing on Hoek–Brown Material.
- Author
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Keawsawasvong, Suraparb, Sangjinda, Kongtawan, Jitchaijaroen, Wittaya, Alzabeebee, Saif, Suksiripattanapong, Cherdsak, and Sukkarak, Raksiri
- Subjects
- *
NONLINEAR regression , *FINITE element method , *PROCESS capability , *REGRESSION analysis - Abstract
The finite element limit analysis solution presented in this paper offers novel approaches for estimating the ultimate bearing capacity of annular foundations on Hoek–Brown criterion. The study examines the effects of five of dimensionless parameters, including the ratio of internal to external radii, the depth ratio, the adhesive factor, the yield parameter, and the geological strength index, on the findings of bearing capacity as well as the processes of collapse. Furthermore, one of the soft-computing regression methodologies, the multi-objective evolutionary polynomial regression analysis (MOGA-EPR) method, is utilized along with the requirement of the FELA outcomes as input data. This paper provides accurate limit-state predictions for annular footings on diverse rock masses using the MOGA-EPR model. By using the MOGA-EPR approach, the findings are highly precise and trustworthy, empowering designers to choose the best annular foundation design for various Hoek–Brown material varieties. Moreover, this study extends its scope by encompassing the application of multiple linear regression, multiple nonlinear regression, and artificial neural network models for an extensive comparative analysis. The amalgamation of these models widens the evaluative framework, fostering a more comprehensive exploration of predictive capabilities and insights into the stability assessment of annular footings across rock mass conditions. Through this multifaceted approach, a holistic comprehension emerges, thereby enhancing the decision-making process pertaining to the design of annular foundations within diverse Hoek–Brown material contexts. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. AN ADAPTIVE DIFFERENTIAL EVOLUTION ALGORITHM WITH A BOUND ADJUSTMENT STRATEGY FOR SOLVING NONLINEAR PARAMETER IDENTIFICATION PROBLEMS.
- Author
-
Wongsa, Watchara, Puphasuk, Pikul, and Wetweerapong, Jeerayut
- Subjects
PARAMETER identification ,DIFFERENTIAL evolution ,BIOLOGICAL evolution ,NONLINEAR regression ,ALGORITHMS - Abstract
Copyright of Informatics Control Measurement in Economy & Environment Protection / Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska is the property of Lublin University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
45. Seismic vulnerability estimation of RC structures considering empirical and numerical simulation methods.
- Author
-
Li, Si-Qi, Du, Ke, Li, Yi-Ru, Han, Jia-Cheng, Qin, Peng-Fei, and Liu, Hong-Bo
- Subjects
SEISMIC response ,EARTHQUAKE hazard analysis ,COMPUTER simulation ,EARTHQUAKE resistant design ,NONLINEAR regression ,STRUCTURAL failures ,STEEL bars - Abstract
Empirical and probabilistic risk analysis methods can relatively accurately predict the seismic vulnerability of reinforced concrete (RC) structures. Using various intensity measures to estimate and forecast the seismic hazard of RC structures can contribute to the development of typical structural seismic resilience and vulnerability models. However, traditional empirical and analytical vulnerability studies rely more on field observation data and seismic risk algorithms and less on numerical simulation analysis for validation and optimization, resulting in limitations and fuzziness in the accuracy of the developed structural risk models. To explore the damage modes of RC frame structures under different intensities, this paper innovatively combines numerical model algorithms with empirical vulnerability methods to conduct empirical vulnerability and numerical simulation analyses on RC structures. Using probability statistics and nonlinear regression analysis methods, a prediction model for estimating the fragility of RC structures was proposed, and 858 RC structure damage samples from a typical city (Dujiangyan) during the Wenchuan earthquake in China on May 12, 2008, were used for model verification and comparative analysis. Using seismic response analysis theory, 901,530 acceleration records of the Wenchuan earthquake detected by eight actual seismic stations were selected, and nonlinear dynamic time history analysis was conducted. A four-story RC structural model was established using finite element software, and numerical simulation analysis was conducted on the model using 117,863 real earthquake acceleration data points obtained from actual monitoring stations during the Wenchuan earthquake. The acceleration time history curves and incremental dynamic analysis curves of the RC structure under different intensity measures were generated. By combining the moire algorithm and numerical simulation technology, damage stress clouds of steel bars and concrete under different intensity measures were generated, and the accuracy of the developed empirical vulnerability model was verified via numerical simulation results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. A Piecewise Linear Regression Model Ensemble for Large-Scale Curve Fitting.
- Author
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Moreno-Carbonell, Santiago and Sánchez-Úbeda, Eugenio F.
- Subjects
MACHINE learning ,REGRESSION analysis ,CURVE fitting ,PARALLEL processing ,PARALLEL algorithms ,NONLINEAR regression - Abstract
The Linear Hinges Model (LHM) is an efficient approach to flexible and robust one-dimensional curve fitting under stringent high-noise conditions. However, it was initially designed to run in a single-core processor, accessing the whole input dataset. The surge in data volumes, coupled with the increase in parallel hardware architectures and specialised frameworks, has led to a growth in interest and a need for new algorithms able to deal with large-scale datasets and techniques to adapt traditional machine learning algorithms to this new paradigm. This paper presents several ensemble alternatives, based on model selection and combination, that allow for obtaining a continuous piecewise linear regression model from large-scale datasets using the learning algorithm of the LHM. Our empirical tests have proved that model combination outperforms model selection and that these methods can provide better results in terms of bias, variance, and execution time than the original algorithm executed over the entire dataset. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Applications of resampling methods in multivariate Liu estimator.
- Author
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Pirmohammadi, Shima and Bidram, Hamid
- Subjects
MULTICOLLINEARITY ,NONLINEAR regression ,REGRESSION analysis ,RESEARCH personnel ,INDEPENDENT variables ,POCKETKNIVES - Abstract
Multicollinearity among independent variables is one of the most common problems in regression models. The aftereffects of this problem, such as ill-conditioning, instability of estimators, and inflating mean squared error of ordinary least squares estimator (OLS), in the multivariate linear regression model (MLRM) are the same that of linear regression models. To combat multicollinearity, several approaches have been presented in the literature. Liu estimator (LE), as a well known estimator in this connection, has been used in linear, generalized linear, and nonlinear regression models by researchers in recent years. In this paper, for the first time, LE and jackknifed Liu estimator (JLE) are investigated in MLRM. To improve estimators in the sense of mean squared error, two known resampling methods, i.e., jackknife and bootstrap, are used. Finally, OLS, LE, and JLE are compared by a simulation study and also using a real data set, by resampling methods in MLRM. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Prediction Of Char Production From Slow Pyrolysis Of Lignocellulosic Biomass Using Multiple Nonlinear Regression And Artificial Neural Network
- Author
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Ting Yan Li, Jiawei Wang, Huan Xiang, Güray Yildiz, and Yang Yang
- Subjects
Coefficient of determination ,business.industry ,Fossil fuel ,Biomass ,Lignocellulosic biomass ,Raw material ,Pulp and paper industry ,slow pyrolysis ,Analytical Chemistry ,Fuel Technology ,Environmental science ,Char ,business ,Nonlinear regression ,Pyrolysis ,lignocellulosic biomass ,artificial neural network ,char - Abstract
Char produced from lignocellulosic biomass via slow pyrolysis have become one of the most feasible alternatives that can partially replace the utilisation of fossil fuels for energy production. In this study, the relationship between compositions of lignocellulosic biomass, operating conditions of slow pyrolysis, and characteristics of produced char have been analysed by using multiple nonlinear regression (MnLR) and artificial neural networks (ANN). Six input variables (temperature, solid residence time, production capacity, particle size, and fixed carbon and ash content) and five responses (char yield, and fixed carbon, volatile matter, ash content, HHV of produced char) were selected. A total of 57 literature references with 393–422 datasets were used to determine the correlation and coefficient of determination (R2) between the input variables and responses. High correlation results (>0.5) existed between pyrolysis temperature and char yield (-0.502) and volatile matter of produced char (-0.619), ash content of feedstock and fixed carbon (-0.685), ash content (0.871) and HHV (-0.571) of produced char. Whilst the quadratic model was selected for the regression model, then the model was further optimised by eliminating any terms with p-values greater than 0.05. The optimised MnLR model results showed a reasonable prediction ability of char yield (R2= 0.5579), fixed carbon (R2= 0.7763), volatile matter (R2= 0.5709), ash (R2= 0.8613), and HHV (R2= 0.5728). ANN model optimisation was carried out as the results showed “trainbr” training algorithm, 10 neurons in the hidden layer, and “tansig” and “purelin” transfer function in hidden and output layers, respectively. The optimised ANN models had higher accuracy than MnLR models with the R2greater than 0.75, including 0.785 for char yield, 0.855 for fixed carbon, 0.752 for volatile matter, 0.951 for ash and 0.784 for HHV, respectively. The trained models can be used to predict and optimise the char production from slow pyrolysis of biomass without expensive experiments.
- Published
- 2021
49. Operation Energy Consumption Estimation Method of Electric Bus Based on CNN Time Series Prediction.
- Author
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Xing, Yan, Li, Yachao, Liu, Weidong, Li, Wenqing, and Meng, Lingxuan
- Subjects
ELECTRIC motor buses ,ENERGY consumption ,TIME series analysis ,DEEP learning ,CONVOLUTIONAL neural networks ,NONLINEAR regression ,REGRESSION analysis - Abstract
In order to further improve the accuracy of electric bus energy consumption estimation and reduce the complexity of using data, the paper proposes a new method for estimating electric bus energy consumption based on a deep learning approach with a data-driven model. The method can estimate the single-trip energy consumption of an electric bus by employing CNN (convolutional neural network) to time series prediction, which takes into account easily accessible trip data of electric buses, including initial SOC (state of charge), average speed, average temperature. First, we need to convert the raw data into a trip dataset by preprocessing the collected real-world trip data of an electric bus. Then, the single trip of the bus from the original station to the terminal station is considered the basic unit for energy consumption estimation, and the trip data are processed in a quasi-time series. Following that, the trip data were modified so that the subsequent convolutional operations more closely matched the interactions between adjacent trips, and a time series prediction method based on CNN was used instead of the regression analysis methods used in traditional data-driven models. Finally, single-trip operation energy consumption estimation of electric buses is achieved with time series prediction based on CNN, and this method is compared and analysed with the LSTM (long-short term memory) time series prediction method and multivariate nonlinear regression prediction methods in traditional data-driven models. The results show that the energy consumption estimation model for electric buses developed in this paper has a higher prediction accuracy, which can improve by 3.68 percent over the traditional multivariate nonlinear regression prediction method and by 1.32 percent over the LSTM time series prediction method. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
50. Survey of Point Cloud Registration Methods and New Statistical Approach.
- Author
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Marek, Jaroslav and Chmelař, Pavel
- Subjects
POINT cloud ,RANDOM fields ,ESTIMATION theory ,POINT set theory ,NONLINEAR regression ,RECORDING & registration ,COVARIANCE matrices - Abstract
The use of a 3D range scanning device for autonomous object description or unknown environment mapping leads to the necessity of improving computer methods based on identical point pairs from different point clouds (so-called registration problem). The registration problem and three-dimensional transformation of coordinates still require further research. The paper attempts to guide the reader through the vast field of existing registration methods so that he can choose the appropriate approach for his particular problem. Furthermore, the article contains a regression method that enables the estimation of the covariance matrix of the transformation parameters and the calculation of the uncertainty of the estimated points. This makes it possible to extend existing registration methods with uncertainty estimates and to improve knowledge about the performed registration. The paper's primary purpose is to present a survey of known methods and basic estimation theory concepts for the point cloud registration problem. The focus will be on the guiding principles of the estimation theory: ICP algorithm; Normal Distribution Transform; Feature-based registration; Iterative dual correspondences; Probabilistic iterative correspondence method; Point-based registration; Quadratic patches; Likelihood-field matching; Conditional random fields; Branch-and-bound registration; PointReg. The secondary purpose of this article is to show an innovative statistical model for this transformation problem. The new theory needs known covariance matrices of identical point coordinates. An unknown rotation matrix and shift vector have been estimated using a nonlinear regression model with nonlinear constraints. The paper ends with a relevant numerical example. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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