"A substantial experimental literature suggests that a personal solicitation is an effective way to induce people to make charitable donations. We examine whether this result generalizes to a non-experimental setting. Specifically, we estimate the effect of a marginal personal solicitation using...

The importance of comprehensive annotations for learning resources is widely recognized. However, it is often unclear how these annotations should be created. A promising solution might be that learners annotate learning resources during execution of learning processes. This paper examines...

One of the principles of managing structured knowledge of an application domain is to exploit the notion of an ontology. Generalization of knowledge entities using formal semantic metadata enables classification and structuring of knowledge for better metadata management. Classification serves...