Browsing by Subject "Single Machine Scheduling"

Now showing 1 - 3 of 3

Open Access
Auction based scheduling for distributed systems
(2005) Zarifoğlu, Emrah
Businesses deal with huge databases over a geographically distributed supply network. When this is combined with scheduling and planning needs, it becomes too difficult to handle. Recently, Fast Consumer Goods sector tends to consolidate their manufacturing facilities on a single supplier serving to a distributed customer network. This decentralized structure causes imperfect information sharing between customers and the supplier. We model this problem as a single machine distributed scheduling problem with job agents representing the customers and the machine agent representing the supplier. For benchmarking purpose, we analyzed the problem under three different scenarios: decentralized utility case (realistic case), centralized utility case, centralized cost case (classical single machine early/tardy problem). We developed Auction Based Algorithm by exploiting the opportunity to use game theoretic approach to solve the problem in the decentralized utility case. We used optimization techniques (Lagrangean Relaxation and Branch-and-Bound) for the centralized cases. Results of our extensive computational experiments indicate that Auction Based Algorithm converges to the upper bound found for the total utility measure.
Open Access
Robustness and stability measures for scheduling policies in a single machine environment
(2002) Gören, Selçuk
Scheduling is a decision making process that concerns allocation of limited resources (machines, material handling equipment, operators, tools, fixtures, etc.) to competing tasks (operations of jobs) over time with the goal of optimizing one or more objectives. The output of this decision process is time/machine/operation assignments. In classical scheduling theory, the objective is generally maximizing some measure of system performance. In addition to classical performance measures two new criteria are used in modern scheduling literature: "robustness" and "stability". In this thesis, we propose several robustness and stability measures and policies. Two new surrogate measures are also developed since the exact measures are difficult to calculate. These surrogate measures are embedded in a tabu search algorithm to generate robust and stable schedules for a single machine subject to random machine breakdowns. We show that our surrogate measures are better than well-known and commonly used average slack method.
Open Access
Single machine total tardiness problem: exact and heuristic algorithms based on Beta-sequence and decomposition theorems
(1994) Kara, Bahar
The primary concern of this thesis is to analyze single machine total tardiness problem and to develop both an exact algorithm and a heuristic algorithm. The analysis of the literature reveals that exact algorithms are limited to 100 jobs. We enlarge this limit considerably by basing our algorithms on the ¡3- Sequence and decomposition theorems from the recent literature. With our algorithm, we exactly solve 200 job problems in low CPU time, and we also solved 120 out of 160 test problems with 500 jobs. In addition we develop a heuristic based on our exact algorithm which results in optimum solutions in 30% of test problems and stays with 9% of the optimal in all test runs.