Browsing by Subject "Time and motion study"

Now showing 1 - 3 of 3

Open Access
A problem space algorithm for single machine weighted tardiness problems
(Taylor & Francis Inc., 2003) Avcı, S.; Aktürk, M. S.; Storer, R. H.
We propose a problem space genetic algorithm to solve single machine total weighted tardiness scheduling problems. The proposed algorithm utilizes global and time-dependent local dominance rules to improve the neighborhood structure of the search space. They are also a powerful exploitation (intensifying) tool since the global optimum is one of the local optimum solutions. Furthermore, the problem space search method significantly enhances the exploration (diversification) capability of the genetic algorithm. In summary, we can improve both solution quality and robustness over the other local search algorithms reported in the literature.
Open Access
Reactive scheduling in a dynamic and stochastic FMS environment
(Taylor & Francis, 2003) Sabuncuoğlu, İ.; Kızılışık, Ö. B.
In this paper, we study the reactive scheduling problems in a dynamic and stochastic manufacturing environment. Specifically, we develop a simulationbased scheduling system for flexible manufacturing systems. We also propose several reactive scheduling policies (i.e. when-to-schedule and how-to-schedule policies) and test their performances under various experimental conditions, processing time variations, and machine breakdowns. Moreover, we compare offline and online scheduling schemes in a dynamic manufacturing environment. The results of extensive simulation experiments indicate that the variable-timeresponse is better than the fixed-time-response. The full scheduling scheme generally performs better than the partial scheduling. Finally, the online scheduling is more robust to uncertainty and variations in processing times than the optimumseeking offline scheduling. A comprehensive bibliography is also provided in the paper.
Open Access
Single machine earliness-tardiness scheduling problems using the equal-slack rule
(Palgrave Macmillan Ltd., 1994) Oğuz, C.; Dincer, C.
The purpose of this paper is to analyze a special case of the non-pre-emptive single machine scheduling problem where the distinct due dates for each job are related to processing times according to the Equal-Slack rule. The scheduling objective is to minimize the sum of earliness and tardiness penalties. After determining some properties of the problem, the unrestricted case is shown to be equivalent to a polynomial time solvable problem, whereas the restricted case is shown to be NP-hard, and suggestions are made for further research.