Research Article
Service Capacity Reserve under Uncertainty by Hospital’s ER Analogies: A Practical Model for Car Services
Table 3
List of acronyms: parameters and variables-simulation inputs and outputs.
| (a) |
| | Acronym | Definition | Source | Parameter |
| | Lab | Retail labour rate | DMS data | Constant | | Ntec | Number of available technicians | | Constant | | WBN | Total number of staffed work bays | | Constant | | Number of work bays per technician (WBN/Ntec) | | Constant (from 1 to 2) |
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| (b) Simulation Random Inputs |
| | Acronym | Definition | Source | Prob. distribution |
| | ED | Elective demand | DMS data | ARIMA | | HPRES | Working time per month (hours) | (399,65; 85,92) | | InvoT | Invoiced time | (373,76; 76,9) | | NED | Nonelective demand (NED = TV – ED) | ARIMA | | Nveh | Number of vehicles arriving to the service per day | (6,13; 1,85) | | PartsCost | Cost of parts sale | (21297,95; 11963,79) | | PS | Parts sale | (27278,41; 13517,82) | | TV | Total demand | ARIMA | | WDM | Working days per month | (21; 1) | | WTD | Daily working time (hours per day) | (6,51; 1,13) |
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| (c) Simulation random outputs |
| | Acronym | Definition | Source |
| | ATPV | Average cycle service time per vehicle (hours) | Queuing + simulation | | CAP | Service incremental capacity | | CAPRNED | Capacity reserve cost to serve all nonelective demands | | CAPRNED1 | Capacity reserve cost to serve 1 unexpected vehicle | | CEW | Empty work bay cost estimation | | DMS | Dealer management system | | EFC | Service system efficiency | | EFCTec | Operating efficiency per technician | | EFCVeh | Operating efficiency per vehicle | | GSR | Monthly gross service revenue estimation | | InvoTn | Invoiced time estimation | | OCC | Service occupancy | | PartsCostn | Cost of parts sale estimation | | PFunit | Profit per vehicle in service | | PSn | Parts sale estimation | | Pstec | Parts sale per technician | | Tcust | Customer waiting time | | TEXP | Monthly workshop total cost estimation | | Tparts | Parts lead time | | TPF | Service total gross profit estimation | | TSR | Total preparation time. TSR = TCust + TParts | | TSW | Service time per vehicle | | VhW | Average number of vehicles that are being worked | | Wtec | Average number of technicians that are working |
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| (d) Other queuing system outputs |
| | Acronym | Definition | Source |
| | f(den_1) | Mathematical operator | Queuing + simulation | | FTI | Fraction of time that a technician is idle | | Average number of vehicles in the Q-NTec | | Lq | Average number of vehicles in the queue | | Probability vehicles are in the queuing system (Q-Ntec) | | Po | Probability of no calling units in the queuing system | | Po−1 | Po inverse | | Arrival rate vehicles/hour | | Service rate vehicles/hour |
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