Structured Spreadsheet Modeling and Implementation

Developing an error-free spreadsheet has been a problem since the beginning of end-user computing. In this paper, we present a methodology that separates the modeling from the implementation. Using proven techniques from Information Systems and Software Engineering, we present strict, but simple, rules governing the implementation from the model. The resulting spreadsheet should be easier to understand, audit and maintain.Comment: In Proceedings of the 2nd Workshop on Software Engineering Methods in Spreadsheet

A Parametric Worst Case Analysis for a Machine Scheduling Problem

We consider the problem of minimizing the makespan when scheduling tasks on two uniform parallel machines, where one machine is q times as efficient on each task as is the other. We compute the maximum relative error of the LPT (largest processing time first) heuristic as a function of q. In the special case that the two machines are identical (q = 1), our problem and heuristic are identical to the problem and heuristic analyzed by Graham [1969]