The Unified Modelling Language (UML) ostensibly assumes a four level (meta) modelling framework, both for its definition and for the conceptual context in which its users operate. In practice, however, it is still dominated by the traditional two level (model + data) view of object modelling and neither supports nor applies the four level framework properly. This not only diminishes the clarity...

Abstract In overly congested airports requests for landing and take-off slots are allocated according to the IATA World Scheduling Guidelines (WSG). A central concept of these guidelines is prioritization satisfaction requested a hierarchy that recognizes historic usage rights slots. number criteria have been proposed in literature optimize airport slot allocation decisions. Multi-objective pro...

The traditional approach in analysing IEA data has been to use single-level statistical models. This paper argues that multilevel modelling offers a wider spectrum in analysing IEA data because of multi-stage sampling, since students are nested within classes, classes within schools, and schools within countries. Two illustrative examples are used to provide support to this argument. In the fir...

Language descriptions are a multi-level issue. In particular, the de nition and handling of instantiation semantics connects three levels. This paper looks at two language workbenches without support for multi-level modelling and their handling of the multi-level part of language descriptions. From these observations, the importance of runtime instantiation in terms of an underlying machine is ...

As the range of modelling approaches that claim to be “multi-level” diversifies, there is growing debate in the literature about what multi-level modelling actually is and what form supporting languages and infrastructures should take. However, there is no consensus yet on how this debate should be framed and what objective criteria should be used to evaluate different approaches. It is clear f...