scholarly journals Multiple Linear Regression Models for Predicting Nonpoint-Source Pollutant Discharge from a Highland Agricultural Region

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1156 ◽  
Author(s):  
Jae Cho ◽  
Jong Lee

Sediment runoff from dense highland field areas greatly affects the quality of downstream lakes and drinking water sources. In this study, multiple linear regression (MLR) models were built to predict diffuse pollutant discharge using the environmental parameters of a basin. Explanatory variables that influence the sediment and pollutant discharge can be identified with the model, and such research could play an important role in limiting sediment erosion in the dense highland field area. Pollutant load per event, event mean concentration (EMC), and pollutant load per area were estimated from stormwater survey data from the Lake Soyang basin. During the wet season, heavy rains cause large amounts of suspended sediment and the occurrence of such rains is increasing due to climate change. The explanatory variables used in the MLR models are the percentage of fields, subbasin area, and mean slope of subbasin as topographic parameters, and the number of preceding dry days, rainfall intensity, rainfall depth, and rainfall duration as rainfall parameters. In the MLR modeling process, four types of regression equations with and without log transformation of the explanatory and response variables were examined to identify the best performing regression model. The performance of the MLR models was evaluated using the coefficient of determination (R2), root mean square error (RMSE), coefficient of variation of the root mean square error (CV(RMSE)), the ratio of the RMSE to the standard deviation of the observed data (RSR) and the Nash–Sutcliffe model efficiency (NSE). The performance of the MLR models of pollutant load except total nitrogen (TN) was good under the condition of RSR, and satisfactory for the NSE and R2. In the EMC and load/area models, the performance for suspended solids (SS) and total phosphorus (TP) was good for the RSR, and satisfactory for the NSE and R2. The standardized coefficients for the models were analyzed to identify the influential explanatory variables in the models. In the final performance evaluation, the results of jackknife validation indicate that the MLR models are robust.

2019 ◽  
Author(s):  
Amrin Amrin

Tingkat inflasi tidak dapat dianggap remeh dalam sistem perekonomian suatu negara dan pelaku bisnis pada umumnya. Jika inflasi dapat diramalkan dengan akurasi yang tinggi, tentunya dapat dijadikan dasar pengambilan kebijakan pemerintah dalam mengantisipasi aktivitas ekonomi di masa depan. Pada penelitian ini akan digunakan metode prediksi neural network backpropagation dan multiple linear regression untuk memprediksi tingkat inflasi bulanan di indonesia, selanjutnya membandingkan manakah yang terbaik dari kedua metode tersebut. Data inflasi yang digunakan bersumber dari Badan Pusat Statistik dari tahun 2006-2015, dimana 80% sebagai data training dan 20% sebagai data testing. Dari hasil analisis data yang dilakukan disimpulkan bahwa Performa model multiple linear regression lebih baik dibandingkan dengan metode neural network backpropagation dengan nilai mean absolute deviation (MAD) sebesar 0.0380, mean square error (MSE) sebesar 0.0023, dan nilai Root Mean Square Error (RMSE) sebesar 0.0481


Author(s):  
Reza Norouzi ◽  
Parveen Sihag ◽  
Rasoul Daneshfaraz ◽  
John Abraham ◽  
Vadoud Hasannia

Abstract This study was designed to evaluate the ability of Artificial Intelligence (AI) methods including ANN, ANFIS, GRNN, SVM, GP, LR, and MLR to predict the relative energy dissipation(ΔE/Eu) for vertical drops equipped with a horizontal screen. For this study, 108 experiments were carried out to investigate energy dissipation. In the experiments, the discharge rate, drop height, and porosity of the screens were varied. Parameters yc/h, yd/yc, and p were input variables, and ΔE/Eu was the output variable. The efficiencies of the models were compared using the following metrics: correlation coefficient (CC), mean absolute error (MAE), root-mean-square error (RMSE), Normalized root mean square error (NRMSE) and Nash–Sutcliffe model efficiency (NSE). Results indicate that the performance of the ANFIS_gbellmf based model with a CC value of 0.9953, RMSE value of 0.0069, MAE value of 0.0042, NRMSE value as 0.0092 and NSE value as 0.9895 was superior to other applied models. Also, a linear regression yielded CC = 0.9933, RMSE = 0.0083, and MAE = 0.0067. This linear model outperformed multiple linear regression models. Results from a sensitivity study suggest that yc/h is the most effective parameter for predicting ΔE/Eu.


Author(s):  
Fitria Habibatul Hamdanah ◽  
Devi Fitrianah

Penjualan merupakan syarat mutlak kelangsungan suatu usaha, karena dengan penjualan maka akan didapatkan keuntungan. Metode Linear Regression dan Generalized Linear Model merupakan metode pendekatan yang didukung dengan perhitungan RSME. RMSE (Root Mean Square Error) berfungsi untuk mendapatkan besaran tingkat kesalahan dari hasil prediksi, dimana semakin kecil (mendekati 0) nilai RMSE maka semakin akurat nilai prediksinya. Pada setiap Usaha Mikro Kecil Menengah (UMKM) aktivitas transaksi dan pelayanan terhadap konsumen setiap harinya semakin lama semakin meningkat, sehingga tanpa disadari hal ini dapat menimbulkan tumpukan data yang semakin membesar. UMKM biasanya mengeluarkan beberapa item berbeda untuk ditawarkan ke pasar dengan harga yang berbeda, namun tidak semua barang banyak peminatnya. Keberhasilan penjualannya menentukan keberlanjutan untuk umkm itu sendiri. Pada penelitian ini akan dibandingkan penggunaan algoritma Linear Regression dengan Generalized Linear Model yang diimplementasikan pada data penjualan yang sudah diinputkan sebelumnya guna menghasilkan prediksi penjualan barang untuk tahun berikutnya. Hasil perhitungan menunjukkan bahwa algoritma Linear Regression dengan nilai RSME, MSE,MAPE sebesar 1,983; 3,933; dan 1,518 sedangkan hasil dari algoritma Generalized Linear Model dengan nilai RSME, MSE, MAPE sebesar 4,827; 23,295; dan 3,882. Berdasarkan perhitungan prediksi oleh algoritma Linear Regression dan Generalized Linear Model dapat disimpulkan bahwa nilai RSME pada algoritma Linear Regression menunjukkan perhitungan paling baik dikarenakan nilai RSME paling kecil.


Irrigation is the most critical process for agriculture, but irrigation is the largest consumer of fresh water and causes the loss of large quantities because of the inaccuracy in crop water estimation. Our proposed system aims to improve irrigation management by estimating the amount of water needed by the crop accurately and reduces the number of meteorological parameters needed for such estimation. Detection of the reference crop evapotranspiration (ETo) is the most critical process in crop water estimation, that is considered through our proposed solution by implementing machine learning models using neural networks and linear regression to predict daily ETo using climate data like temperature, humidity, wind speed, and solar radiation. Comparing our system results with FAO-56 Penman-Monteith ET0 and cropwat8.0 software as benchmark, show that our proposed system is better than the linear regression model, in terms of determination coefficient (R^2)=.9677 and root mean square error(RMSE) =.1809, while the multiple linear regression model achieved determination coefficient (R^2)=.68 and root mean square error(RMSE) =3.01. Our system then used the predicted ETo and Crop coefficient (Kc) from FAO, to estimate crop evapotranspiration (ETc) for precision irrigation target.


2017 ◽  
Vol 63 (5) ◽  
pp. 282-290
Author(s):  
Anna E. Gavrilova ◽  
Elena V. Nagaeva ◽  
Olga Yu. Rebrova ◽  
Tatiana Yu. Shiryaeva

Background. Predicting the efficacy of rGH therapy in patients with GH deficiency, based on the final achieved height (FAH) criterion, is an important tool for the clinician. It enables a personalized approach to the treatment of patients with GH deficiency: to recommend careful adherence to the regimen and dosage of the drug, evaluate the efficacy of therapy in different groups of patients, and clearly demonstrate the factors affecting the FAH indicator. Aim — to develop mathematical models for predicting FAH and its standard deviation score (SDS) in patients with GH deficiency in the Russian population. Material and methods. For simulation, we used the data of 121 patients diagnosed with GH deficiency who received rGH since the time of diagnosis to the time of final height and were followed-up at the Institute of Pediatric Endocrinology of the Endocrinology Research Centre in the period between 1978 and 2016. As model predictors, we used 11 indicators: the gender, chronological age at the time of GH deficiency diagnosis, puberty status, disease form, regularity of rGH therapy, height SDS at birth, height SDS at the time of GH deficiency diagnosis, bone age at the time of GH deficiency diagnosis, bone age/chronological index, SDS of a genetically predicted height, and maximum stimulated GH level in a clonidine test. To generate models, we used multiple linear regression, artificial neural networks (ANNs), and the Statistica 13 software. Results. The developed ANNs demonstrated a high accuracy of predicting FAH (the root-mean-square error was 4.4 cm, and the explained variance fraction was 76%) and a lower accuracy of predicting the FAH SDS (the root-mean-square error was 0.601 SDS, and the explained variance fraction was 42%). Linear regression models that were based on quantitative predictors only had a substantially worse quality. Free software implementation was developed for the best produced ANN. Conclusion. An ANN-based software-implemented model for predicting FAH uses indicators available for any clinician as predictors and can be used for individual prediction of FAH. In the future, the use of larger databases for simulation will improve the quality of predicting the efficacy of rGH therapy.


2021 ◽  
Vol 13 (9) ◽  
pp. 1630
Author(s):  
Yaohui Zhu ◽  
Guijun Yang ◽  
Hao Yang ◽  
Fa Zhao ◽  
Shaoyu Han ◽  
...  

With the increase in the frequency of extreme weather events in recent years, apple growing areas in the Loess Plateau frequently encounter frost during flowering. Accurately assessing the frost loss in orchards during the flowering period is of great significance for optimizing disaster prevention measures, market apple price regulation, agricultural insurance, and government subsidy programs. The previous research on orchard frost disasters is mainly focused on early risk warning. Therefore, to effectively quantify orchard frost loss, this paper proposes a frost loss assessment model constructed using meteorological and remote sensing information and applies this model to the regional-scale assessment of orchard fruit loss after frost. As an example, this article examines a frost event that occurred during the apple flowering period in Luochuan County, Northwestern China, on 17 April 2020. A multivariable linear regression (MLR) model was constructed based on the orchard planting years, the number of flowering days, and the chill accumulation before frost, as well as the minimum temperature and daily temperature difference on the day of frost. Then, the model simulation accuracy was verified using the leave-one-out cross-validation (LOOCV) method, and the coefficient of determination (R2), the root mean square error (RMSE), and the normalized root mean square error (NRMSE) were 0.69, 18.76%, and 18.76%, respectively. Additionally, the extended Fourier amplitude sensitivity test (EFAST) method was used for the sensitivity analysis of the model parameters. The results show that the simulated apple orchard fruit number reduction ratio is highly sensitive to the minimum temperature on the day of frost, and the chill accumulation and planting years before the frost, with sensitivity values of ≥0.74, ≥0.25, and ≥0.15, respectively. This research can not only assist governments in optimizing traditional orchard frost prevention measures and market price regulation but can also provide a reference for agricultural insurance companies to formulate plans for compensation after frost.


Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1020
Author(s):  
Yanqi Dong ◽  
Guangpeng Fan ◽  
Zhiwu Zhou ◽  
Jincheng Liu ◽  
Yongguo Wang ◽  
...  

The quantitative structure model (QSM) contains the branch geometry and attributes of the tree. AdQSM is a new, accurate, and detailed tree QSM. In this paper, an automatic modeling method based on AdQSM is developed, and a low-cost technical scheme of tree structure modeling is provided, so that AdQSM can be freely used by more people. First, we used two digital cameras to collect two-dimensional (2D) photos of trees and generated three-dimensional (3D) point clouds of plot and segmented individual tree from the plot point clouds. Then a new QSM-AdQSM was used to construct tree model from point clouds of 44 trees. Finally, to verify the effectiveness of our method, the diameter at breast height (DBH), tree height, and trunk volume were derived from the reconstructed tree model. These parameters extracted from AdQSM were compared with the reference values from forest inventory. For the DBH, the relative bias (rBias), root mean square error (RMSE), and coefficient of variation of root mean square error (rRMSE) were 4.26%, 1.93 cm, and 6.60%. For the tree height, the rBias, RMSE, and rRMSE were—10.86%, 1.67 m, and 12.34%. The determination coefficient (R2) of DBH and tree height estimated by AdQSM and the reference value were 0.94 and 0.86. We used the trunk volume calculated by the allometric equation as a reference value to test the accuracy of AdQSM. The trunk volume was estimated based on AdQSM, and its bias was 0.07066 m3, rBias was 18.73%, RMSE was 0.12369 m3, rRMSE was 32.78%. To better evaluate the accuracy of QSM’s reconstruction of the trunk volume, we compared AdQSM and TreeQSM in the same dataset. The bias of the trunk volume estimated based on TreeQSM was −0.05071 m3, and the rBias was −13.44%, RMSE was 0.13267 m3, rRMSE was 35.16%. At 95% confidence interval level, the concordance correlation coefficient (CCC = 0.77) of the agreement between the estimated tree trunk volume of AdQSM and the reference value was greater than that of TreeQSM (CCC = 0.60). The significance of this research is as follows: (1) The automatic modeling method based on AdQSM is developed, which expands the application scope of AdQSM; (2) provide low-cost photogrammetric point cloud as the input data of AdQSM; (3) explore the potential of AdQSM to reconstruct forest terrestrial photogrammetric point clouds.


2013 ◽  
Vol 860-863 ◽  
pp. 2783-2786
Author(s):  
Yu Bing Dong ◽  
Hai Yan Wang ◽  
Ming Jing Li

Edge detection and thresholding segmentation algorithms are presented and tested with variety of grayscale images in different fields. In order to analyze and evaluate the quality of image segmentation, Root Mean Square Error is used. The smaller error value is, the better image segmentation effect is. The experimental results show that a segmentation method is not suitable for all images segmentation.


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