The 5th International Symposium on Rules: Research Based and Industry Focused (RuleML-2011@IJCAI), collocated in Barcelona, Spain, with the 22nd International Joint Conference on Artificial Intelligence, was the premier place to meet and to exchange ideas from all fields of rule technology. The aim of RuleML-2011 was to build a bridge between academia and industry in the field of rules and semantic technology, and so to stimulate the cooperation and interoperability between business and research, by bringing together rule system providers, participants in rule standardization efforts, open source communities, practitioners, and researchers. This annual symposium is the flagship event of the Rule Markup and Modeling Initiative (RuleML).

The RuleML Initiative (www.ruleml.org) is a non-profit umbrella organization of several technical groups organized by representatives from academia, industry and government working on rule technology and its applications. Its aim is to promote the study, research and application of rules in heterogeneous distributed environments such as the Web. RuleML maintains effective links with other major international societies and acts as intermediary between various ‘specialized’ rule vendors, applications, industrial and academic research groups, as well as standardization efforts from, for example, W3C, OMG, and OASIS.

The International Symposium on Rules, RuleML, has evolved from an annual series of international workshops since 2002, international conferences in 2005 and 2006, and international symposia since 2007. In 2011 two instalments of the RuleML Symposium took place. The first one was held in conjunction with IJCAI 2011 (International Joint Conference on Artificial Intelligence) in Barcelona in July, and the second was collocated with the Business Rule Forum in November in Fort Lauderdale, Florida, USA. For RuleML-2011@IJCAI, a selection of the best papers was presented during a joint session with IJCAI, called “Large Track of Best Papers from Sister Conferences.” The authors of these papers also submitted a revised version of their papers for inclusion in the IJCAI proceedings.