Decision support system for lumber procurement and dry kiln scheduling: A fuzzy system theory application.

摘要

In this research, lumber kiln drying operations are represented as a scheduling model involving n independent and non-preemptive jobs on m non-identical/identical, parallel machines (kilns) ;The algorithm has been incorporated in a decision support system (DSS) to assist in lumber management. The DSS interactively assists the user in determining a plan for drying/purchasing lumber to meet demand requirements and minimize total costs. The DSS (1) utilizes heuristic scheduling algorithms to obtain good solutions for the sequence, timing, and content of each kiln charge; (2) evaluates the costs of obtaining dry lumber from alternative sources, e.g., green, air-dried, and kiln-dried lumbers. (3) constructs a total cost function that considers procurement costs, in-house drying costs, inventory carrying costs, and then recommends the timing and quantity of purchases from each source.;Crisp and fuzzy scheduling models are incorporated into the DSS. Due dates, dry kiln processing times, and kiln availability dates are represented as fuzzy numbers to reflect the uncertainty associated with the "true" values of these variables. Use of the DSS is described and dry kiln loading schedules developed using crisp and fuzzy models are compared. The benefits of using fuzzy models versus crisp models are reported.