Multi release modeling of a software with testing effort and fault reduction factor

In today's fast moving day to day life almost everything is more or less dependent on software. This dependence on software has increased the demand of reliable software in no time. Hence software firms are now a days releasing multiple versions of the software instead of providing a software with less number of bugs and removing the bugs of the previous version in the next up-gradation Firms remove the bugs of the previous version in the next up-gradation or by updating the software. But removal of bugs is not a simple task and at the time of removal it may be possible that testing team may introduce some new bugs to it. In the existing software reliability literature numerous models are proposed incorporating effort spent on removing the bugs. In this paper we have incorporated one more attribute of fault reduction factor in the effort based multi release modelling of a software. Fault reduction factors (FRFs) play an important role in software reliability and are generally defined as the ratio of the total number of reduced faults to the total number of failures experienced. FRFs are not fixed and it is affected by many factors, e.g., imperfect debugging, resource allocations, and debugging time lag. Taking this into consideration we propose two effort based multi up-gradation software reliability growth models incorporating time dependent FRF. Numerical illustration of the proposed model is done on a real life data set of tandem computers for four release.