Scheduling the repair of aircraft components - a case study

In aircraft components maintenance shops, components are distributed amongst repair groups and their respective technicians based on the type of repair, on the technicians skills and workload, and on the customer required dates. This distribution planning is typically done in an empirical manner based on the group leader’s past experience. Such a procedure does not provide any performance guarantees, leading frequently to undesirable delays on the delivery of the aircraft components. Among others, a fundamental challenge faced by the group leaders is to decide how to distribute the components that arrive without customer required dates. This paper addresses the problems of prioritizing the randomly arriving of aircraft components (with or without pre-assigned customer required dates) and of optimally distributing them amongst the technicians of the repair groups. We proposed a formula for prioritizing the list of repairs, pointing out the importance of selecting good estimators for the interarrival times between repair requests, the turn-around-times and the man hours for repair. In addition, a model for the assignment and scheduling problem is designed and a preliminary algorithm along with a numerical illustration is presented.

From illiteracy to literacy in adult- hood: A microlongitudinal study

Little is known about literacy acquisition in adults. Yet, our former studies suggest that the majority of the changes induced by literacy in children also occur in adulthood. Based on this observation as well as on what we know from developmental studies on reading acquisition, we designed an intensive literacy course in which each difficulty (either phono- logical or visual) of the alphabetic code is introduced in turn in lessons dedicated to overcoming it. We applied this course for 3 1∕2 months to 9 adult Portuguese illiterates. They were tested five times: two before starting the course (pre-tests), two during the course, and just after they completed the course. We tracked their evolution in reading and writing, metaphonology, memory for spoken nonwords, speech in noise perception, and visual abilities, including mirror-image discrimination. Most participants learned to read and write and showed associated enhancements in several domains, in particular in phonological skills.