Editorial message: special track on coordination models, languages and applications

The notion of coordination is more and more pervading many research fields both inside and outside Computer Science. Many research areas such as software engineering, intelligent systems, agent technologies, Internet applications, programming languages, parallel and distributed computing, all raise issues that concern the interaction among different sorts of entities --- processes, objects, components, agents --- as well as its management. Despite their apparent diversity, this wide and heterogeneous range of problems actually exhibit large overlaps, and can be effectively faced and solved using a relatively reduced set of conceptual tools --- the notion of coordination model among the main ones. The purpose of a coordination model is represent and shape the space of interaction among entities --- whatever they are, however they interact. >From an engineering viewpoint, coordination languages and systems should enable engineers to integrate a number of possibly heterogeneous components, and to govern their interaction so as to form a (potentially distributed) software system with desired characteristics and functionalities.Accordingly, the Special Track on Coordination Models, Languages and Applications takes deliberately a broad view of what is coordination. Besides the traditional areas covering data-driven, control-driven, and hybrid models and languages, the track invited contributions from several areas where the concept of coordination is relevant, such as multiagent systems, Web applications, software architectures, middleware platforms, knowledge-based systems, groupware and workflow management, etc.In response to the call for papers, 42 high quality submissions from 18 different countries were submitted to this special track, and fed into the reviewing process. Altogether, there were more than 100 reviewers, and over 235 reviews were submitted by them --- an average of more than 5 reviews for each paper. Based on the reviewers' reports, the general ACM SAC guidelines for acceptance and rejection of submissions, and the unavoidable time and space constraints associated with any conference, it was possible to select only 16 of these submissions as regular papers for presentation at the track. In the process, a number of good and interesting papers had to be rejected. Among the papers presented at the special track, a further selection and revision process will lead to the publication of a Special Issue on Coordination and Knowledge Engineering that will appear on The Knowledge Engineering Review (http://uk.cambridge.org/journals/ker/).