Maintenance of object oriented systems through re-engineering: a case study

Unregulated evolution of software often leads to software ageing which not only makes the product difficult to maintain but also breaks the consistency between design and implementation. In such a case, it may become necessary to re-engineer the software so that it becomes maintainable again. In this paper we present the case study of the reengineering of the People Tracking subsystem of a surveillance system written in C++. We discuss the problems, the challenges and the approaches taken, and we show how the re-engineered product is now better maintainable. We also discuss the generation of the relevant artefacts - from requirement document through to design document.