In this paper optimal outpatient appointment scheduling is studied. A local search procedure is derived that converges to the optimal schedule with a weighted average of expected waiting times of patients, idle time of the doctor and tardiness (lateness) as objective. No-shows are allowed to happen. For certain combinations of parameters the well-known Bailey-Welch rule is found to be the optim...

We present new MIP formulations for the single machine total weighted tardiness problem. These formulations are based on a partition of the time horizon into intervals. This partition is done in such a way that the problem reduces to the problem of assigning jobs to intervals. This leads to a compact formulation that can be solved with standard integer programming techniques. We also introduce ...

In this paper we present a set of benchmark instances and a benchmark instance generator for a single-machine scheduling problem known as the weighted tardiness scheduling problem with sequence-dependent setups. Furthermore, we argue that it is an ideal benchmark problem for soft computing in that it is computationally hard and does not lend itself well to exact solution procedures. Additionall...

In this paper we study the permutation #owshop scheduling problem with an increasing and decreasing series of dominating machines. The objective is to minimize one of the "ve regular performance criteria, namely, total weighted completion time, maximum lateness, maximum tardiness, number of tardy jobs and makespan. We establish that these "ve cases are solvable by presenting a polymonial-time s...

In this note, we consider a single machine scheduling problem with generalized total tardiness objective function. A pseudo-polynomial time solution algorithm is proposed for a special case of this problem. Moreover, we present a new graphical algorithm for another special case, which corresponds to the classical problem of minimizing the weighted number of tardy jobs on a single machine. The l...

We consider a single-machine scheduling problem with equal-sized jobs. The objective is to minimize the maximum weighted earliness-tardiness and due-date costs. We present an algorithm to solve this problem. Our algorithm makes use of bottleneck jobs and priority queues, and has a computational complexity of O(n logn). This complexity is a significant improvement of the existing algorithm in th...

We propose a general approach for nding minmax regret solutions for a class of combinatorial optimization problems with an objective function of minimax type and uncertain objective function coe cients. The approach is based on reducing a problem with uncertainty to a number of problems without uncertainty. The method is illustrated on bottleneck combinatorial optimization problems, minimax mul...

The study deals with scheduling a set of independent jobs with unequal release dates to minimize total weighted tardiness on a single machine. We propose new dominance properties that are incorporated in a branch and bound algorithm. The proposed algorithm is tested on a set of randomly generated problems with 10, 15 and 20 jobs. To the best of our knowledge, this is the first exact approach th...

Previous research in the single machine total weighted tardiness problem (SMTWTP) has led to the proposition of effective local search strategies. At least existing benchmark instances from the literature do not pose a challenge for state-of-the-art algorithms. This paper describes the proposition of two classes of novel instances for the single machine total weighted tardiness problem. In resp...

art exact algorithms suffer from relatively poor performances. On the other hand the problem has been successfully tackled by local search heuristic algorithms where the neighborhood of a solution is usually computed by applying swap (a.k.a. pairwise interchange) operators to the working sequence. Dynasearch is a neighborhood search technique introduced by Congram et al. [1] whose main feature ...