Rule Languages for the Semantic Web

Ontology plays a major role in Semantic Web to describe the meaning about data on the web. Some inferences can be gleaned from the ontology model itself, but others may not be expressible in the ontology language (usually OWL) and require a more functional representation. Semantic Rules are required to infer implicit inference. It is away of expressing additional things that can be inferred from your dataset. Rules layer is on top of the OWL in semantic web-layered architecture. This layer is less developed and active area of research. Various Rule languages have been developed by the authors for the Semantic web such as RuleML (Rule Markup Language), SWRL (Semantic Web Rule Language), RIF (Rule Interchange Format), R2ML (REWERSE Rule Markup Language) and many more. This paper aims to discuss the state of the art with respect to semantic rule-based technologies. It gives an overview of the rules and rule languages that are currently available to support rule-based- and ontology-based reasoning, and it also reviews some of the limitations of these technologies in terms of their inability to deal with uncertain or imprecise data, incomplete knowledge, decidability and their poor performance in some reasoning contexts.