In a multi-project environment, we sometimes need to periodically schedule the tasks for each project and assign staff to the tasks. Such a decision-making problem has been studied in literature; however, learning effect of staff has not been considered in previous studies. This research formulates a mixed nonlinear program for project scheduling and staff allocation problems, which considers learning effect of staff. The objective function is to minimize outsourcing costs. A genetic algorithm (GA) is proposed to solve the problem. Experiments for solving various sizes of test problems has been carried out to validate the proposed GA.

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This paper formulates and solves a route planning problem for semiconductor manufacturing. In order to quickly respond to rising demand, a semiconductor company usually adopts a dual-fab strategy to expand capacity. That is, two fab sites are built as neighbours and can easily share capacity. Through the capacity-sharing design, a product may be produced by a cross-fab route. That is, some operations of a product are carried out in one fab and the other operations in the other fab. This leads to a routing planning problem, which involves two decisions -determining the cut-off point of the cross-fab route and the route ratio for each product -in order to maximise the throughput subject to a cycle time constraint. An LP-GA method is proposed to solve the route planning problem. We first use the LP module to make the cut-off point decisions, and proceed to use the GA module for making the decision on the route ratio. Experimental results show that the LP-GA method significantly outperforms other methods.Keywords: operations management; operations strategy; operations planning IntroductionThe semiconductor manufacturing industry has to consider the following three factors when expanding capacity. The equipment costs are very expensive, perhaps costing over one billion dollars for a 12 inch wafer fab. The lead time for equipment acquisition is quite long, ranging from 3 to 9 months. However, building the factory space is relatively inexpensive, but with a much longer lead time -taking about one to two years.In order to respond quickly to rising demand, a semiconductor company usually adopts a dual-fab strategy to expand capacity. That is, a large-scale factory space that can accommodate two fabs is established in advance. Then, the equipment for the two fabs is gradually moved into the space over time according to market demand. The two fabs, close to each other in location, support each other and should be managed in an integrated manner.In such a dual-fab configuration, a relatively easy way to manage is to manufacture each wafer job in one fab. That is, each fab is run separately, without any mutual support in capacity. Such a separated-operation paradigm usually leads to an underutilisation of equipment. To remedy the underutilisation issue, a cross-fab production paradigm is proposed. This means that a wafer job is partly manufactured in one fab and partly manufactured in the other fab.