An enhanced rostering model for airline crews
June 2001
Computers & Operations Research 28(7):671-688
Authors: 
Herbert Dawid 
Johannes König 
Christine Strauss
Link to ResearchGate: An_enhanced_rostering_model_for_airline_crews
Abstract: This paper introduces an efficient adaptation of the branch-and-bound technique that solves real-world rostering problems for airline crews. The efficiency of the algorithm is based on the exploitation of rostering-specific properties (e.g. variable selection, branching strategy and cutting-planes). This approach shortens the solution process and outperforms standard techniques. Furthermore, we formally introduce a general concept of downgrading that makes it possible to solve certain rostering problems that might otherwise have no solution. This paper also computes a sample monthly schedule on the basis of a medium-sized European airline’s real data. Scope and purpose: The scheduling of airline crews and the assignment of crews to flights are important and difficult planning functions that most airlines undertake on a monthly basis. Solving a so-called rostering problem includes the construction of individualized schedules that take into account various pre-assignments (like training or observer flights), as well as crew requests (such as days off or preferred flights). The European rostering approach implies large scale and complex integer problems with 10000 variables and several hundred constraints. This paper develops a new algorithm (SWIFTROSTER) that incorporates several strategies that exploit problem-specific knowledge in order to solve even large problems in very short runtimes, thus outperforming commercial solvers. Using real data from a medium-sized European airline the article demonstrates that our approach generates efficient solutions that can be applied in the real world to produce crew schedules.
Supplements in Airline Cabin Service
February 2000
In book: Information and Communication Technologies in Tourism 2000 – Proceedings of the International Conference in Barcelona, Spain, 2000
Publisher: Springer Vienna
Editors: Daniel Fesenmaier, Stefan Klein, Dimitros Buhalis
Authors: Johannes König Christine Strauss
Link to ResearchGate: Supplements_in_Airline_Cabin_Service
Abstract: Airlines and their services are very often part of the supply chain in tourism. Therefore, the quality of on-board service contributes to the passengers’ overall satisfaction with the entire journey. Given that the cost of personnel is the second highest component of direct operational costs next to fuel, airlines are more inclined to reduce the level of their workforces rather than to invest in additional services. Our paper presents how the quality level of services can be raised by ensuring that appropriate steps are taken during the operational planning phase in which crews are assigned to certain flights. A basic crew rostering model is extended by introducing constraints that produce a schedule that raises a flight’s service quality without causing additional costs. The ideas presented in this paper are also applicable to cruise lines, international hotel chains, and railway companies.
Rostering-Integrated Services and Crew Efficiency
January 2000
Information Technology & Tourism 3(1):1-18
Authors: Johannes König Christine Strauss
Link to ResearchGate: Rostering-Integrated_Services_and_Crew_Efficiency
Abstract: Given that the cost of personnel is one of the highest direct operational costs, service-intensive enterprises are more inclined to reduce the level of their workforces rather than to invest in additional services. Our paper presents (1) how the quality level of services can be augmented and (2) how the workforce can be used efficiently by extending a basic model through adequate constraints. Although this article focuses exemplarily on airlines the concepts proposed are also applicable to crew rostering for airlines, cruise lines, international hotel chains, and railway companies. An adaptation of the efficient rostering algorithm SWIFTROSTER is used to provide exemplary results for such service improvements and efficiency measures.