preventive maintenance scheduling of generating units is addressed as a long-term scheduling in power system studies aiming to increase the reliability incorporating cost reduction. it consists of knowing which generating units should be shut down for regular safety inspection. in this paper, a new formulation of preventive maintenance scheduling associated with cost reduction index (cri) is pr...

Aggregate production planning (APP) is one of the most important issues carried out in manufacturing environments which seeks efficient planning, scheduling and coordination of all production activities that optimizes the company's objectives. In this paper, we develop a mixed integer linear programming (MILP) model for an integrated aggregate production planning system with closed loop supply ...

Software-engineering academics focussed for many years on the costs of developing the first version of a product, and ignored the costs of subsequent maintenance. We taught our students the 'waterfall model', and biased research towards the sort of tools and ideas that complemented it, such as formal methods. Meanwhile the economics of software had changed. Software is now so complex that the o...

This paper investigates the effects of preventive-maintenance cost functions on the optimal preventive-maintenance policy for a leased product with Weibull life-time distribution. During the lease period, any product failures are rectified by minimal repairs and may incur a penalty to the lessor, if the time duration for performing a minimal repair exceeds a pre-specified time limit. To reduce ...

In an empirical analysis of sixty-five software maintenance projects in a large IBM COBOL transaction processing environment, the impacts of correctable software complexity upon project costs were estimated. Module size, procedure size, and the use of complex branching were all found to significantly affect software maintenance costs. It was estimated that projects involving maintenance of syst...