Optimal Scheduling for New Product Development

L. Najmias, C. Schmidt and I.E Grossmann


Screen Shots:
Initial screen
Gantt Chart

PRODEV is a computer program written in C language for optimal scheduling for new product development. It is based on the MILP (Mixed Integer Linear Program) developed by Craig Schmidt and Ignacio Grossmann (1998). The model considers a schedule with N tasks each having a probability of success, and K scenarios with given probabilities of occurrence. For each scenario every task has a cost and a duration.

Given the above information, there are two models PRODEV can optimize

  • .The first model is a fixed completion time model, where the schedule's overall completion time is set a priori by the user.
  • In the second model,which is a fixed income function model, the user supplies a piecewise linear income function and PRODEV determines the optimal schedule length.

For both models, the user can supply a discount rate (in fractional form),and precedence constraints that tell PRODEV if a given task must precede or succeed another task in the schedule.

Once the data of the problem is supplied, PRODEV generates a new text file called "master.dat" containing all the information. This file is used by GAMS to run the model from a master file called "master.gms", which contains all the model equations. The optimization is performed using the OSL solver for both LP and MILP problems. After this step, GAMS generates three text files containing information to derive the optimal schedule (""), summary of results ("master.out) and Gantt chart ("") of the problem. The first text file is used by DOT to derive the optimal schedule in a postscript format (called ""),which is then displayed using GHOSTVIEW. The second text file is copied into a new text file called "filename.out", which contains all the output information in table form, and is displayed using EMACS. The third data file generated by GAMS is again used by DOT to generate a postscript file called "", which contains the Gantt chart of the problem and is displayed using GHOSTVIEW.

Please note that it is not possible to view the derived schedules in due to the fact that neither DOT nor GHOSTVIEW are able to function in this operating system. If possible, the user is adviced to run PRODEV from, where a fuller, faster version of PRODEV can be found in the path: /usr/user/lnn/PRODEV/.

PRODEV has been developed by Leonardo Najmias in line with Craig Schmidt's PhD research project, under the supervision of Ignacio Grossmann.

References for PRODEV:

Schmidt, C.W. and I.E. Grossmann, "Optimization Models for the Scheduling of Testing Tasks in New Product Development", Ind.Eng.Chem. Res. 35, 3498-3510 (1996).