Overview of TRP Decision Support System ( Assignment)

1. Overview of TRP Decision Support System( Assignment) Using QS Software

2. Overview of ASTS Decision Support System • This program solves assignment (AS) and traveling salesman (TS) problems. • The size of problems solved by this program depends on the memory in your computer. • For the assignment problems, tasks may represent jobs while the objects may indicate workers. • The assignment is solved by the Hungarian method. • The traveling salesman problem is solved by a branch-and-bound procedure which repeatedly solves the assignment problem by assigning city- to-city links. • The program provides free and fixed formats to enter and modify input data. • The problem can be saved on or read from a disk(ette).

3. ASTS Cont. • The ASTS Decision Support System allows you to define names of objects and tasks with up to 6 characters. • The default names are O1,O2,...,On and T1,T2,...,Tn for AS problems and C1,C2,...,Cn for TS problems. • For small problems with up to 9 objects and 9 tasks, you have the option of displaying every iteration of the Hungarian method. • ASTS can solve much larger problems but without displaying iterations. • After the problem has been solved, you can display and print the final solution. • At any time, you may press the F8 key to hardcopy the output on the screen; or press the F9 key to return tothe function menu; or press the F10 key to exit QS. • Enjoy using your ASTS Decision Support System!

4. The Assignment Method • The assignment method is a specialized linear programming solution procedure that is rather simple to perform. • Given a table of jobs and machines, it develops an opportunity cost matrix for assigning particular jobs to particular machines. • With this technique, only one job may be assigned to each machine.

5. The Procedure • Perform row reductions by subtracting the minimum value in each row from all other row values. • Perform column reductions by subtracting the minimum value in each column from all other column values. • Cross out all zeros in the matrix using the minimum number of horizontal or vertical lines. • If the number of lines equals the number of rows in the matrix, an optimum solution has been reached and assignments can be made where the zeros appear. Otherwise, modify the matrix by subtracting the minimum uncrossed value from all other uncrossed values and adding the same amount to all cells where two lines intersect. All other values in the matrix remain unchanged. • Repeat steps 3 and 4 until an optimum solution is reached.

6. Solutions • Solutions are given in terms of minimizing cost or maximizing profit. • The solution could represent minimized time, maximized quality levels, or other variables. • The solution can be provided for minimizing the sum of assignment values or minimizing the worst value. • The assignment method produces good, but not necessarily optimum, results when minimizing a maximum value.

7. Sequencing • When more than one job is assigned to a machine or activity, the operator needs to know the order in which to process the jobs. • The process of prioritizing jobs is called sequencing. • If no particular order is specified, the operator would probably process the job that arrived first. • This default sequence is called first-come, first served (FCFS). • Or, if jobs are stacked upon arrival to a machine, it might be easier to process the job first that arrived last and is now on top of the stack. This is called last-come, first-served (LCFS) sequencing.

8. QS Main Menu This is the QS main menu Users can choose from these different programs The two being used today will be Transshipment Assignment / Traveling Salesman

10. Demonstration • Let’s take a look at a few examples now using QS software to solve and analyze transshipment & assingment problems.