Eg n jjobs thru m obs machines for each machine there

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: thru m obs machines) For each machine, there are n factorial order of factorial jobs. Jobs may also be processed on machines in any order. (Almost 25billion possible schedules) schedules) Johnson’s algorithm provides a efficient solution to scheduling n jobs on two machines. 7 All All Possible Schedules for Two Jobs on Two Machines Two Example 8.5 Job 1 2 3 4 5 Machine A 5 1 9 3 10 Machine B 2 6 7 8 4 8 Example Example Job 1 2 3 4 5 6 7 8 Machine A 5 7 3 0 2 5 4 7 Machine B 3 6 4 7 1 4 1 6 Results for Multiple Machines The optimal solution for scheduling n jobs on two machines is always a permutation schedule (that is, jobs are done in the same order on both machines). (This is the basis for Johnson’s algorithm.) algorithm.) For three machines, a permutation schedule is still optimal if we restrict attention to total flow time only. Under rare circumstances, the two machine algorithm can be used to solve the three machine case. When scheduling two jobs on m machines, the problem can be solved by graphical means. 9 Assembly Line Balancing Characteristics of the Assembly Line Balancing Characteristics problem. A collection of n tasks must be completed on each item item Tasks are assigned to stations. Tasks must be sequenced properly, and certain tasks may not be done at the same station. The objective is to assign tasks to stations to minimize the cycle time, C. The general problem is difficult to solve optimally, but effective heuristics are available. (the text discusses one known as the ranked positional weight technique.) technique Schematic Schematic of a Typical Assembly Line Typical 10 Reading Reading Textbook page 455 – 465. Selected Problems 3, 4, 5, 7, 10 3, 11...
View Full Document

Ask a homework question - tutors are online