Information retrieval (IR) functions serve a critical role in many information systems. There are many techniques and operations have been developed in IR that do not require radical changes or re-implementation. The implemented IR algorithms can be distributed or their functions made available through the framework of web services. A key idea behind web services is that frequently used functions can be implemented once and offered to other application or software environments through programmatic interfaces. Web services in the IR domain have not been widely tested. Library of User-Oriented Concepts for Access Services (LUCAS) offers IR functions such as term extraction, term clustering, and document classification as web services. It has successfully served other information systems such as the Biological Knowledge through Ontologies (BioKnOT) and the Extensible Networked Association-based Bioinformatics Learning Environment (ENABLE) Knowledge Base. In this poster, we demonstrate the utility of LUCAS to the ENALBE system. ENABLE project is funded by NSF to extend digital library technologies in the emerging domain of bioinformatics and develop novel interfaces to support association-based learning of bioinformatics resources. The ENABLE Knowledge Base provides functions for bioinformatics resource collection and management. We will present the design of the LUCAS system, implemented using the web service framework, and how the LUCAS system can be used to develop effective and efficient complex information systems. LUCAS interacts with the ENABLE Knowledge Base by means of web services, providing an automated indexing service. Sections that follow present further details.