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This paper aims to address the issue of long-term stability of services and systems depending on service-oriented architecture that has become a popular architecture in systems development and is often implemented using Web services. However, the dependency, especially on externally provided services, can impact the reliability of a system. This is often caused by the loose coupling also implying a less stringent policy for change management and notifications. Therefore, the authors characterise the types of changes that can happen in remote services and propose the concept of resilient web services (RWSs) as an example on how to upgrade existing services to better support the long-term stability of services and systems.

Having analysed several use cases where systems broke because of external dependencies not correctly maintained, the authors derived requirements for RWSs.

By means of a prototype implementation and evaluation of this solution in a case study, the feasibility of the approach was verified. Several scenarios of changes in WSs were simulated, correctly identified and responded to.

The authors propose a set of extensions to existing standards such as Web Services Description Language to improve the long-term availability of services in SOAs. A prototype implementation was developed for service monitoring and RWSs.

The purpose of this paper is to investigate the feasibility of solving an integrated flight scheduling, fleet assignment and crew pairing problem for an on-demand service using a small, up to 19-seater, aircraft.

Evolutionary algorithm is developed to solve the problem. Algorithm design assumes indirect solution representation that allows to evaluate partially feasible solutions only and speed up calculations. Tested algorithm implementation takes advantage of the graphic processing unit.

Performed tests confirm that the algorithm can successfully solve the defined integrated scheduling problem.

The presented algorithm allows to optimise on-demand transport service operation within minutes.

Optimisation of operation cost contributes to better accessibility of transport.

The presented integrated formulation allows to avoid sub optimal solutions that are results of solving sequential sub problems. Indirect representation and evaluation strategy can be applied to speed up calculations in other problems as well.