Modeling Hydrology Data Using a Robust Least Trimmed Squares Fuzzy Regression Approach

Document Type : Original Paper

Authors

1 Department of Statistics, Semnan University, Semnan, Iran

2 Semnan University

Abstract

Estimation methods of parameters of fuzzy least-squares regression have very sensitivity to unusual data (e.g. outliers). In the presence of outliers, most of the existing estimation methods of parameters of this kind of models using least-squares approach provide unexpected and unreliable estimators with amounts of errors. Therefore, in this paper a robust least trimmed squares fuzzy regression model is described for modeling for crisp input-fuzzy output variables. In this approach, the constructed target function in model parameter estimation problem in such a way which minimizes the sum of the  smallest squared residuals. This method has an algorithm that estimates the optimal values of the parameters based on different selected combinations of  good observations of the data set of size . Therefore, this method has the ability of reducing the effects of such a data in estimation of the parameters of the model. Finally, the investigated fuzzy regression model is applied and studied to modeling real-world data set in hydrology which sometimes contains outlier points. In this regard, a comparison study between the proposed method and ordinary least squares fuzzy regression method is considered. The comparison results of the applied study reveal that for this particular data set the proposed method performs better fitting than the well-known ordinary fuzzy least-squares regression model. Also the proposed method identified the points that have bad effect on estimation problem of the parameters.

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[1] Huber, P. and Ronchetti, E.M. (2009). Robust Statistics, 2ed. Wiley, Hoboken, NJ.
[2] Rousseeuw, P.J. and Leroy, A.M. (1987). Robust Regression and Outlier Detection, Wiley, Hoboken, NJ.
[3] Andersen, R. (2007). Modern Methods for Robust Regression, Sage: Thousand Oaks, CA.
[4] Roozbeh, M. (2016). Robust ridge estimator in restricted semi-parametric regression ‎models, ‎ Journal Multivariate Analysis147, 127-144.
[5] D'Urso, P., Massari, R. and Santoro, A. (2011). Robust fuzzy regression analysis, Information Sciences, 181, 4154-4174.
[6] Chachi, J. and Roozbeh, M. (2017). A fuzzy robust regression approach applied to bedload transport data, Communications in Statistics-Simulation and Computation46, 1703-1714.
[7] Chachi, J., Taheri, S.M., Fattahi, S. and Hosseini Ravandi, S.A. (2017). Two robust fuzzy regression models and their applications to predict imperfections of cotton yarn, Journal of Textiles and Polymers, In Press.
[8] Arefi, M. and Taheri, S.M. (2015). Least squares regression based on Atanassov’s intuitionistic fuzzy inputs-outputs and Atanassov’s intuitionistic fuzzy parameters, IEEE Transactions on Fuzzy Systems, 23, 1142-1154.
[9] Ferraro, M.B., Coppi, R., Gonzalez-Rodriguez, G. and Colubi, A. (2010). A linear regression model for imprecise response, International Journal of Approximate Reasoning, 51, 759-770.
[10] Chachi, J. and Taheri, S.M. (2016). Multiple fuzzy regression model for fuzzy input-output data, Iranian Journal of Fuzzy Systems13, 63-78.
[11] Chachi, J., Taheri, S.M. and Arghami, N.R. (2014). A hybrid fuzzy regression model and its application in hydrology engineering, Applied Soft Computing25, 149-158.
 [12] Chachi, J., Taheri, S.M. and Rezaei Pazhand, H. (2016). Suspended load estimation using L1-Fuzzy regression, L2-Fuzzy regression and MARS-Fuzzy regression models, Hydrological Sciences Journal61, 1489-1502.
[13] Coppi, R., D'Urso, P., Giordani, P. and Santoro, A. (2006). Least squares estimation of a linear regression model with LR fuzzy response, Computational Statistics and Data Analysis51, 267-286.
[14] Hung, W.L. and Yang, M.S. (2006). An omission approach for detecting outliers in fuzzy regressions models, Fuzzy Sets and Systems157, 3109-3122.
[15] Peters, G. (1994). Fuzzy linear regression with fuzzy intervals, Fuzzy Sets and Systems 63, 45-55.
[16] Zimmermann, H.J. (2001). Fuzzy Set Theory and Its Applications, 4th ed., Kluwer Nihoff, Boston.
[17] Chang, P.T. and Lee, S. (1994). Fuzzy linear regression with spreads unrestricted in sign, Computers and Mathematics with Applications, 28, 61-70.
[18] Fox, J. and Weisberg, S. (2011). An R Companion to Applied Regression. 2nd ed., Sage Publications: Thousand Oaks, CA.