Showing papers on "Single-machine scheduling published in 1989"

Schedule generation and reconfiguration for parallel machines

Abstract: A methodology for scheduling independent jobs with due dates on identical, parallel machines is presented. The jobs have different levels of importance and various processing times on the machines, and the objective is to minimize the total weighted job tardiness of the schedule. Since the problem is NP hard, the goal is not to obtain the optimal schedule. Rather, an efficient near-optimal algorithm based on Lagrangian relaxation is presented. This approach provides a lower bound on the cost, which can be used as a measure of suboptimality. According to an implementation for a work center at Pratt and Whitney, most schedules generated are within 1% of the optima with reasonable CPU times. Furthermore, the method provides valuable job interaction information, which shop floor management uses to answer 'what if' questions, to reconfigure the schedule to accommodate dynamic changes, and to schedule new jobs. >

Single machine scheduling with controllable processing times and number of jobs tardy

Abstract: Most scheduling research has treated individual job processing times as fixed parameters. In many practical situations, however, a manager may exert processing time control through the allocation of a limited resource. We consider the problem of joint sequencing and resource allocatin when the scheduling criterion of interest is the number of tardy jobs. Theoretical results are derived that aid in developing the tradeoff curve between the number of tardy jobs and the total amount of allocated resource

Single-machine scheduling to minimize absolute deviation of completion times from a common due date

Abstract: The article considers a single-machine n-job scheduling problem to minimize the sum of absolute lateness given a common due date. Two models are defined depending on whether the start time t0 of schedules is arbitrary or fixed. Conditions are provided when those two models coincide. The developed branch-and-bound procedure is tested on nine known examples from the literature (6 ⩽ n ⩽ 14) and 90 medium-size random problems (15 ⩽ n ⩽ 25) with a fixed t0.

A Heuristic Solution Procedure to Minimize T on a Single Machine

Abstract: In this paper, a heuristic procedure utilizing the adjacent pairwise interchange (API) methodology to minimize mean tardiness (\(\overline{T}\)) in single-machine scheduling is presented. Results indicate that it provides a much better solution than does the Wilkerson-Irwin heuristic algorithm, which also tries to minimize \(\overline{T}\). Experimental results suggest that the heuristic solution is not affected by problem size, which is important if larger problems are to be solved. Also, the heuristic is not affected by the tightness of due dates.

On the real-time control of flexible manufacturing systems

Abstract: Additional results in the analysis of scheduling flexible manufacturing systems using the model proposed by J.R. Perkins and P.R. Kumar (IEEE Trans. on Autom. Control, vol.34, no.2, p.139-48, Feb. 1989) are presented. The concept of idling is used to derive a new lower bound on the performance of any bounded single machine scheduling policy. A discrete-time linear system is used to compute the backlog trajectories for a class of clearing policies. An example of unbounded backlog in a network is presented, using a clear-a-fraction policy. >

Minimizing the number of grab's changes in a single machine scheduling problem

Abstract: N operations subject to precedence constraints are to be sequenced on a single machine. Each operation can be executed by exactly one of the machine's grabs. The task is to find a schedule minimizing the number of grab's changes. This “Robot Sequencing Problem” was introduced and studied by K. Richter. Here we study its graph theoretical counterpart called “Acyclic Subdivision Problem” and the complexity of a generalization called “Restricted Robot Sequencing Problem”.