TY - JOUR ID - 7113 TI - Codifying A Proper Mathematical Model for Predicting The Repair of The Tractors Used in Shahid Beheshti Cultivation Firm of Dezfoul. JO - International Journal of Advanced Biological and Biomedical Research JA - IJABBR LA - en SN - 2383-2762 AU - Amoozadeh, Rahim AU - Sheykh Davoudi, Mohammad Javad AU - Ghasemnejad, Heidar Ali AU - Dehghani, Vahid AU - Eshraghi Mofrad, Farajolla AD - MA, Department of Agriculture, Islamic Azad University, Shooshtar Branch, Shooshtar, Iran AD - Associate Professor, Department of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran AD - Department of Agriculture, Islamic Azad University, Shooshtar Branch, Shooshtar, Iran Y1 - 2014 PY - 2014 VL - 2 IS - 2 SP - 526 EP - 534 KW - Harvester KW - Replacement age KW - Mathematical model KW - Neural network DO - N2 - This study tries to codify a proper mathematical model which can be predict the costs of repair and maintaining the tractors as precisely as possible for three common models of tractors in Shahid Beheshti cultivation firm in Andimeshk-Ahvaz road of Dezfoul. Studied tractors include: Newhland TM155 Tractor which is chosen from the most perfect file of 10 tractor machines and Jandier tractor-3140 of 35 machines. Then we calculated  the cumulative values ​​of the two sets of data was used for different years of tractors working  fitted to the final performance of the mathematical model of the six (linear exponential reverse multiple, second and third degree ) the by method of least squares and use of an computer software. With this operation, the most proper model of estimating maintenance cost for all three types of tractors is obtained as a multiplicative model and the corresponding parameters were calculated. In addition, the final model which is the best fit for a cumulative repair costs for operating hours of all tractors, was determined by multiplying. In order to determine the economic life (replacement age) 61 tractors in three different models based on price, the amount of interest rate and annual depreciation was calculated for each model and used along with the annual cost of maintenance for determining the economic life. UR - https://www.ijabbr.com/article_7113.html L1 - https://www.ijabbr.com/article_7113_348e572071d818140bb9537352050ff2.pdf ER -