Pruning rules for optimal runway sequencing

This paper investigates runway sequencing for real world scenarios at one of the world's busiest airports, London Heathrow. Several pruning principles are introduced that enable significant reductions of the problem's average complexity, without compromising the optimality of the resulting sequences, nor compromising the modelling of important real world constraints and objectives. The pruning principles are generic and can be applied in a variety of heuristic, meta-heuristic or exact algorithms. They could also be applied to different runway configurations, as well as to different variants of the machine scheduling problem with sequence dependent setup times, the generic variant of the runway sequencing problem in this paper. They have been integrated into a dynamic program for runway sequencing, which has been shown to be able to generate optimal sequences for large scale problems at an extremely low computational cost, whilst considering complex non-linear and non-convex objective functions that offer significant flexibility to model real world preferences and real world constraints. The results shown here counter the proliferation of papers that claim that runway sequencing problems are too complex to solve exactly and therefore attempt to solve them heuristically

Relationship between supply chain integration and performance

This study analyzes survey-based studies examining the benefits of supply chain integration (SCI) and presents opportunities for further empirical examination. The literature review method is used to evaluate the empirical research published from 1990 to 2012. The analysis reveals that internal integration serves as a foundation for establishing external collaboration. There is empirical evidence on the positive effect of supplier integration on performance, whereas the findings on benefits through customer integration are conflicting. While researchers have made significant progress in our understanding of SCI, there is a substantial need for more work to provide in-depth insights into the potential of SCI and to improve the methodological issues. This study makes three contributions. First, this study expands the current understanding of benefits and considerations in implementing internal, supplier, and customer integration. Second, this study provides a critique of the empirical work and offers research agendas that can stimulate future researchers to carefully explore the topic. Finally, this study enhances the quality of analysis by employing the five-step approach proposed by Vokurka and O\u27Leary-Kelly (J Oper Manag 18(4):485-501, 2000). © 2013 Springer Science+Business Media New York