on after-tax cash
flow. The objective of this model is to maximise the net present value (NPV) of the
7282 W.-H. Tsai et al.
after-tax cash flows over a project life of N years. NPV maximisation incorporates three
important elements: the magnitude of project cash flows, the net change in investment, and
the timing of the cash flows. The generalised after-tax cash flows for a typical GMS project
can be expressed as follows: