Scheduling with a due-window for acceptable lead-times

Due-dates are often determined during sales negotiations between customers and the sales team of the firm. In the preliminary (pre-sale) stage, the customer provides a time interval (due-window) of his preferred due-dates. This interval reflects acceptable leadtimes, which are functions of the customer resource constraints (e.g. storage or personnel limitations). If the due-dates are assigned either prior to or after the due-window, the firm is penalized accordingly. The final contract refers to the penalties of the actual delivery times as well. Thus, for given (realized) due-dates, the firm is also penalized according to the earliness/tardiness of the delivery time of the products. The model introduced in this paper considers both parts of the sales negotiations (i.e., determination of the time interval for acceptable due-dates, and earliness/tardiness penalties of the actual delivery times). Scheduling literature contains three major procedures for assigning due-dates to jobs: ( ) assigning a common due-date for all the jobs (also known as CON), ( ) assigning jobdependent due-dates which are (linear) functions of the job processing times (also known as SLK), and ( ) assigning job-dependent due-dates which are penalized if exceed prespecified deadlines (also known as DIF). One extension of these models is to a setting of due-window. In this setting, jobs completed within a time interval (rather than at a time point) are not penalized. Jobs completed prior to or after this time interval (window) are penalized according to their earliness/tardiness. The extensions of CON to a setting of common due-window (also known as CONW), and that of SLK to a due-window (SLKW) have been solved and published. The extension of DIF to a due-window is presented in this paper. ISS & MLB―September 24-26, 2013