List Scheduling in Order of α-Points on a Single Machine
نویسنده
چکیده
Many approximation results for single machine scheduling problems rely on the conversion of preemptive schedules into (preemptive or non-preemptive) solutions. The initial preemptive schedule is usually an optimal solution to a combinatorial relaxation or a linear programming relaxation of the scheduling problem under consideration. It therefore provides a lower bound on the optimal objective function value. However, it also contains structural information which is useful for the construction of provably good feasible schedules. In this context, list scheduling in order of so-called α-points has evolved as an important and successful tool. We give a survey and a uniform presentation of several approximation results for single machine scheduling with total weighted completion time objective from the last years which rely on the concept of α-points.
منابع مشابه
The Power of α–Points in Preemptive Single Machine Scheduling
We consider the NP-hard preemptive single machine scheduling problem to minimize the total weighted completion time subject to release dates. A natural extension of Smith’s ratio rule is to preempt the currently active job whenever a new job arrives that has higher ratio of weight to processing time. We prove that the competitive ratio of this simple on-line algorithm is precisely 2. We also sh...
متن کاملMinimizing Total Weighted Tardiness with Drop Dead Dates in Single Machine Scheduling Problem
This paper deals with minimization of tardiness in single machine scheduling problem when each job has two different due-dates i.e. ordinary due-date and drop dead date. The drop dead date is the date in which jobs’ weights rise sharply or the customer cancels the order. A linear programming formulation is developed for the problem and since the problem is known to be NP-hard, three heuristic...
متن کاملJIT single machine scheduling problem with periodic preventive maintenance
This article investigates a JIT single machine scheduling problem with a periodic preventive maintenance. Also to maintain the quality of the products, there is a limitation on the maximum number of allowable jobs in each period. The proposed bi-objective mixed integer model minimizes total earliness-tardiness and makespan simultaneously. Due to the computational complexity of the problem, mult...
متن کاملSingle-machine scheduling considering carryover sequence-dependent setup time, and earliness and tardiness penalties of production
Production scheduling is one of the very important problems that industry and production are confronted with it. Production scheduling is often planned in the industrial environments while productivity in production can improve significantly the expansion of simultaneous optimization of the scheduling plan. Production scheduling and production are two areas that have attracted much attention in...
متن کاملMinimizing the Number of Tardy Jobs in the Single Machine Scheduling Problem under Bimodal Flexible and Periodic Availability Constraints
In single machine scheduling problems with availability constraints, machines are not available for one or more periods of time. In this paper, we consider a single machine scheduling problem with flexible and periodic availability constraints. In this problem, the maximum continuous working time for each machine increases in a stepwise manner with two different values allowed. Also, the durati...
متن کامل