The Ontology Modularization tool implemented an algorithm for extracting modules from OWL ontologies. The algorithms and the characteristics of the extracted modules are described in our WWW-2007 paper: "Just the Right Amount: Extracting Modules From ontologies" . The module extraction functionality has been implemented using the well-known OWL API, and integrated in the ontology editor Swoop.
Currently, the user interface of Swoop provides functionality for:
CEL (classifier for EL) is the first reasoner for the description logic EL+, supporting as its main reasoning task the computation of the subsumption hierarchy induced by EL+ ontologies. The most distinguishing feature of CEL is that, unlike other modern DL reasoners, it implements a polynomial-time algorithm. The supported description logic EL+ offers a selected set of expressive means that are tailored towards the formulation of medical and biological ontologies.
The InstExp (Instance Explorer) tool supports and guides the semi-automatic completion of ontologies by adding either new subsumption relationships or new counterexamples. More precisely, InstExp is an interactive tool that aims to support enriching an ontology by asking questions to a domain expert. It asks questions of the form "Is it true that objects that have properties a,b,c also have the properties d, e, f?". The domain expert is expected to answer "yes" or "no". If she answers with "no", then she is expected to provide a counterexample, and this counterexample is added to the ontology. If she answers "yes", then the ontology is updated with a new inclusion axiom. When the process stops, the ontology is complete in a certain sense. The advantage of the method is that it guarantees to ask the minimum number of questions to the expert in order to acquire the missing part of the knowledge.
The Sonic (Simple ontology non-standard inference component) system implements a collection of non-standard inferences. The implemented inferences are the basis for a number of approaches to extend and maintain ontologies as for instance the bottom-up approach. The Sonic system comes in two parts: the Sonic server and the Sonic plug-in. The Sonic server implements inferences such as computation of (least) common subsumers, concept approximation and concept matching. The plug-in supplies a GUI to access these inferences from within the ontology editor Protege.
Quonto is a Java-based reasoner for DL-Lite with GCIs that is able to manage a large amount of concept and role instances (from thousands to millions) through relational database technology. Quonto is the only system that currently supports query answering of unrestricted unions of conjunctive queries over description logics. Currently, Quonto has its own Java-based interface, and accepts inputs in a proprietary XML format.
The RacerPro Description Logic and Semantic Web inference system supports the SHIQ(Dn) description logic (DL). A highly optimized tableaux calculus is implemented. As a description logic system, RacerPro's most prominent features are the support of so-called ABoxes as well as for expressive Concrete Domains. Furthermore, RacerPro contains a high-performance query and rule language called nRQL. From a theoretical perspective, nRQL offers at least so-called grounded conjunctive queries, but goes far beyond the expressivity of grounded conjunctive queries (e.g., non-monotonic features, classical negated roles and expressive concrete domain querying features are provided). From the viewpoint of the Semantic Web, RacerPro implements OWL Lite and OWL DL (currently with approximations for nominals). Other relevant Semantic Web languages such as SWRL and SPARQL are supported as well. RacerPro uses the AllegroGraph triple store of Franz Inc. in order to realize persistent and scalable RDF(S) processing and shallow reasoning capabilities (e.g., inference-aware SPARQL queries can be evaluated on secondary memory). The RacerPro server supports a number of protocols, among them the semantic middleware standards such as DIG with extensions.
RacerPorter is the graphical default client for RacerPro. It supports textual (shell-based) as well as widget- and graph-based interaction modes. Different tabs of its multi-tabbed interface visualize different perspectives of a RacerPro server. Various different RacerPro servers and corresponding sessions can be managed and maintained in parallel. RacerPorter is primarily an ontology browsing and inspection tool (a so-called OBIT), although textual authoring facilities are provided as well - an Emacs-compatible editor with buffer-evaluation mechanism is included. RacerPorter employs a simple and coherent yet powerful usage concept - a clipboard not only provides a data structure for input/output argument passing in order to realize functional compositions of inference services invoked by the user, but is also used to control focus of and navigation in the provided graph displays (taxonomy display, ABox graph, role hierarchy display). Another emphasis is put on ad-hoc querying mechanisms (e.g., powerful shell-based interaction), thus semantic ad-hoc queries can control e.g., the graph displays.
OntoSynt tool provides an automatic support for extracting from a relational database schema its conceptual view. That is, it extracts semantics "hidden" in the relational sources by wrapping them by means of an ontology. The approach is specifically tailored for semantic information access: in order for queries over the ontology to be answered by using the data residing in the relational sources. In such setting, the semantic mapping between the database and its conceptualisation is a crucial aspect, which is captured by associating views over the data source to elements of the extracted ontology.
ICOM is an advanced CASE tool which allows the user to design multiple extended Entity-Relationship diagrams with inter- and intra-schema constraints. Complete logical reasoning is employed by the tool to verify the specification, infer implicit facts, devise stricter constraints, and manifest any inconsistency. The intention behind ICOM is to provide a simple, freeware conceptual modelling tool that demonstrates the use of, and stimulates interest in, the novel and powerful knowledge representation based technologies for database and ontology design. In particular, we are interested to cooperate with researchers and companies considering the opportunity to incorporate these technologies in their tools. A new version of ICOM for designing UML class diagrams is under development.