Optimal software implementation considering reliability and cost

It is becoming increasingly difficult to create software products that simultaneously provide high reliability, rapid delivery and low cost. This research deals with the cost of achieving reliable software. Assume a software package has been designed and is ready for implementation. To implement this software package, a set of modules will have to be purchased and many programming and integration tasks will have to be performed. The performance of a programming task consists of the detailed design of a module, coding and unit testing. An integration task consists of the additional testing and debugging needed when the code included in separately tested tasks is joined together. The implementation process ends when the package has been integrated and tested. A model for deriving cost allocations is presented. The objective of the model is to maximize reliability while satisfying a budget constraint. The option of developing modules in-house as well as the option of purchasing them if available are considered in the optimization. The paper includes a branch and bound scheme to derive an optimal solution.