Many distributed data and knowledge base applications call for a structured approach to collaborative construction of large ontologies (conceptualizations of objects, properties, and relationships between objects of interest in specific domains). This award from the National Science Foundation to ISU researchers Dr. Vasant Honavar, Dr. Giora Slutzki, and doctoral student Jie Bao working in collaboration with Dr. Doina Caragea (KSU) and Dr. George Voutsadakis (LSSU), provides support for research aimed at addressing the need of such applications for ontology languages, distributed reasoning algorithms, and software tools that support rapid collaborative assembly and use of complex ontologies through partial and selective reuse of independently created ontology modules. The researchers will explore the language features, syntax, and semantics of modular ontology languages, develop a family of description logics (DL) based modular ontology languages, namely Package-Based Description logics (P-DL) as well as open source software tools for collaborative construction and use of ontologies in information integration and knowledge discovery applications (e.g., in comparative genomics). The resulting tools can potentially transform distributed data and knowledgebase applications in the same way that the World-Wide Web has transformed the construction, sharing and use of hyperlinked documents and Wiki has transformed encyclopedia construction.