In this article we answer the complexity question of two dual criteria scheduling problems which had been open for a long time. Both problems are single machine scheduling problems and both have the number of tardy jobs as the primary criterion. However, the first problem has the total completion time and the second one has the total tardiness as the secondary criterion. We show that both probl...

This paper deals with the permutation flowshop scheduling problem time lags constraints to minimize total weighted tardiness criterion by using Branch and Bound algorithm. A new lower bound was developed for problem. The computational experiments indicate that proposed algorithm provides good solution in terms of quality requirements.

In this paper, we present a Branch-and-Bound procedure to minimize total tardiness on one machine with arbitrary release dates. We introduce new lower bounds and we generalize some well-known dominance properties. Our procedure handles instances as large as 500 jobs although some 60 jobs instances remain open. Computational results show that the proposed approach outperforms the best known proc...

We study the approximability of minimum total weighted tardiness with a modified objective which includes an additive constant. This ensures the existence of a positive lower bound for the minimum value. Moreover the new objective has a natural interpretation in Just-In-Time production systems.

In this paper, we present a Branch and Bound procedure to minimize total tardiness on one machine with different release dates. We introduce a new lower bound and we generalize some well-known dominance properties. Our procedure handles instances as large as 500 jobs although some 60 jobs instances remain open. We also show how we can generalize different techniques to minimize total completion...

This paper proposes exact algorithms to generate optimal timing schedules for a given sequence of operations in job shops minimize the total weighted earliness and tardiness. The are proposed two shop scheduling scenarios, one involving due dates only last operation each other all on jobs. Computational experiments benchmark problem instances reveal that, case scenario job, faster than those ge...