Single machine scheduling models with deterioration and learning: handling precedence constraints via priority generation

We consider various single machine scheduling problems in which the processing time of a job depends either on its position in a processing sequence or on its start time. We focus on problems of minimizing the makespan or the sum of (weighted) completion times of the jobs. In many situations we show that the objective function is priority-generating, and therefore the corresponding scheduling problem under series-parallel precedence constraints is polynomially solvable. In other situations we provide counter-examples that show that the objective function is not priority-generating.

Capturing teachers' experience of learning design through case studies

This article distinguishes three dimensions to learning design: a technological infrastructure, a conceptual framework for practice that focuses on the creation of structured sequences of learning activities, and a way to represent and share practice through the use of mediating artefacts. Focusing initially on the second of these dimensions, the article reports the key findings from an exploratory study, eLIDA CAMEL. This project examined a hitherto under-researched aspect of learning design: what teachers who are new to the domain perceive to be its value as a framework for practice in the design of both flexible and classroom-based learning. Data collection comprised 13 case studies constructed from participants' self-reports. These suggest that providing students with a structured sequence of learning activities was the major value to teachers. The article additionally discusses the potential of such case studies to function as mediating artefacts for practitioners who are considering experimenting with learning design.