Abstract
Sugarcane harvesting is the most critical operation within sugarcane agro-industrial companies. Simultaneously with the harvest, sugarcane transportation is carried out using transport baskets (bins). In the case of sugarcane transportation, since the systems are mechanical, their reliability decreases as usage and age increase. Therefore, annual maintenance plays a vital role in enhancing the reliability of these transport machines. This research was conducted using Classic and Fuzzy GERT (Graphical Evaluation and Review Technique) methods at the Dehkhoda Sugarcane Agro-Industrial Company during the 2023-2024 crop year. The Work Breakdown Structure (WBS) and the GERT network model for the repair of sugarcane transport baskets were developed. Following the scheduling phase, the results obtained from the GERT method were compared with the actual time spent on system repairs to determine the accuracy of the estimates. The completion time for repairing a sugarcane transport basket was estimated at 102.44 hours using the Classic GERT method. However, using the Fuzzy GERT method, the calculated repair times were 140.06, 107.30, and 74.55 hours (representing the fuzzy intervals). Furthermore, the results indicated that 23.28% of the actual repair completion times fell outside the estimated fuzzy time range. The findings demonstrated that the resulting network model provides maintenance managers with a clear framework for making timely decisions, ensuring that the execution phase aligns with the planned schedule and operations are completed within the optimal timeframe.
EXTENDED ABSTRACT
Introduction 
Sugarcane is one of the most important industrial products in Iran, serving as the primary source of sugar production and a key supplier of raw materials for numerous ancillary industries. It is only commercially cultivated in Khuzestan Province. The area under sugarcane cultivation in Khuzestan Province is 135,000 hectares. In sugarcane farming and industry companies, the most important operation is sugarcane harvesting, and this stage has a major contribution to the profitability or loss of these companies. In mechanical sugarcane harvesting, sugarcane fields are first set on fire to destroy the leaves, then the sugarcane is harvested with a harvester. At the same time as the harvesting operation, sugarcane is also transported by basket. The optimal and appropriate use of sugarcane carrying baskets, combined with a proper balance between the level of harvesting operations and the number of active machines, ensures that the operation starts and ends at the right time. This prevents losses due to delays in sugarcane harvesting and reduces additional costs. In the case of sugarcane transportation, since the systems in question are mechanical, the reliability of the system decreases with increasing use and also with its increasing lifespan. Therefore, annual repairs play a crucial role in enhancing the reliability of sugarcane carrying machines.
Material and Methods 
This research was conducted using the classical and fuzzy Garrett method in Dehkhoda Sugarcane Cultivation and Industry Company in the 1402-1403 crop year. The work breakdown structure diagram and the Garrett network model of sugarcane basket repairs were drawn. In this research, after scheduling, the results obtained from the Garrett method were compared with the actual time spent on repairs of the sugarcane carrying system, and the fit of the estimates was determined. For this purpose, to determine the actual time required for repairs of the sugarcane carrying system, a sample was randomly selected from the sugarcane carrying baskets, and the actual duration of repairs in each was determined. Then, the actual time of completion of the operation was compared with the estimated time. The sugarcane carrying system in Dehkhoda Sugarcane Cultivation and Industry Company includes 45 18-ton baskets. In this research, to schedule the annual repairs of the carrying system, statistics and data related to the repairs of 25 sugarcane carrying baskets were collected. Data from other devices was used to measure the actual time of repairs against the calculated schedule.
Results and Discussion 
The completion time of the sugarcane cart repairs was estimated to be 102.44 hours using the classic Garrett method. However, in the fuzzy Garrett method, the calculated times for sugarcane cart repairs were 140.06, 107.30, and 74.55 hours. The results also showed that 23.28 percent of the actual completion times of the cart repairs were estimated outside the fuzzy time. Solving the fuzzy lattice network for sugarcane basket repairs involves evaluating the network loops and the nodes. The outputs of this method include the operation completion time and the scheduling of other nodes in the network, which were obtained by performing calculations for node and end node evaluation. The operation completion time is a fuzzy number, and considering that the input factors of the network are triangular fuzzy numbers, the result of the operation completion time is also a triangular fuzzy number. That is, in fuzzy grid networks, the operation completion time is not a definite number, but rather a time interval and a fuzzy number that aligns with reality and helps eliminate tensions in the operation monitoring sessions. The fuzzy time for completing the maintenance of the basket is equal to T ̃_project=MT ̃_E=(74.55,107.30,140.06)(time unit: hours). Now, the maintenance manager has a time interval for completing the operation and can analyze it based on α slices. α can be considered as a risk level, and the decision maker can calculate and analyze the operation completion time interval at different risk levels. The lower (optimistic) and upper (pessimistic) limits of the α=0.5 cutoff for the basket repairs were obtained as 90.92 and 123.68 hours, respectively. The larger α is, the smaller the desired interval and the greater the accuracy. Therefore, the project manager can calculate and analyze the time interval required to complete the operation at different risk levels, and it is better to consider α as large. Additionally, the average time for basket repairs was determined to be 107.30 hours through defuzzification. However, the results obtained from the Garrett method in this study are close to the actual completion time of the operation, making the estimates more accurate. The actual duration of annual repairs for 20 baskets (out of a total of 45 baskets) at Dehkhoda Agriculture and Industry Company, which were repaired during the 1402-1403 crop year, was determined based on the information available in the company's mechanical equipment technical office. 23.28 percent of the actual completion times of basket repairs are estimated to be outside the fuzzy time.
Conclusions 
The fuzzy Garrett method provides the repair unit manager with the opportunity to place the completion time in the estimated range appropriately, by considering other effective factors involved in the operation, so that there is no disruption in the implementation of activities and on the other hand, the costs of not completing the work on time are minimized. It also provides the possibility to create cuts at different time points and monitor the process of operation execution, modifying it as necessary. Finally, implementing and making the method practical and getting feedback, defining and determining the sugarcane machinery repair system and creating an information management system for them, examining the possibility of allocating resources and balancing the cost-time of sugarcane transportation system repairs with network models, and carefully and comprehensively examining the lags during work and the reasons for delays in operations in the sugarcane transportation system repair process and providing solutions to reduce them are suggested.
Acknowledgements
The authors would like to thank Shahid Chamran University of Ahvaz, for providing funding for this research.
Author Contributions
Mehdi Anafecheh: Data collection and processing
Nasim Monjezi: Supervision and management
Data Availability Statement
This section details where supporting data can be found, typically including links to publicly archived datasets. If no data is reported, "Not applicable" should be stated.
Ethical Considerations
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Conflict of Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper
Funding Statement
The author(s) received no specific funding for this research