The eXtensible Knowledge Server (XKS™)

The XKS™ is our ontology-based, deductive data base management system (DBMS).
It is designed to perform sophisticated queries involving concepts such as but by no means limited to:

• location and geospatial reasoning
• extensive inference on antecedent facts,
• time and temporal reasoning,
• provenance and information security.

Controlling Logic

The IODE™ and XKS™ use ISO Standard Common Logic, extended with temporal reasoning and quantification over predicates. We can also ingest W3C OWL for customers with commitments to that standard.

Query

The XKS™ query tools enable analysts to perform complex, ad hoc queries that are impossible or prohibitively difficult with standard SQL querying.

Characteristics of the OW XKS™ include:

• Ontology-based deductive DBMS
• Integrated inference & storage
• Ontology as schema, views, constraints
• ACID properties
• Proof carrying
• Built-in temporal-interval logic
• Constraint checking
• Semantic query optimization
• Thread-level parallelism
• Runs on all later versions of Windows including Vista, and Linux
• Java 1.5 (and later) client-server API

XKS™ Functional Components

The Server Presentation Layer is Ontology Works' API for programmatically interfacing with all of Ontology Works Knowledge Servers. It is a JDBC-flavored API, consisting of database connection management, logical entity creation, logical fact assertion and deletion, and logical query processing. This layer also provides a number of supporting tools to construct legal queries and logical sentences.

The Semantic Query Optimizer (SQO) provides a wide range of static query optimizations. Common first order logic queries are manipulated in the context of the ontology the database is using and optimized for parallel execution. The SQO uses many logic transforms to arrive at provably best-case expressions for inputs.

Our Inference Engine (PiQuE Engine) is highly optimized for parallel query processing, working with the Semantic Optimizer to allow many parts of a single query expression to run in parallel. This is useful even in a single processor machine since different parts of a query typically need to access different logical extents, and the parallel nature of the Pique engine means that computational steps can be underway while disk accesses is blocking.

The XKS Scalable Storage Layer utilizes commodity relational database systems as its primary storage layer. A variety of relational DBMS' can be used, ranging from small, embedded engines to enterprise scale servers. Depending on the store chosen, this model allows for the Virtual Knowledge Server Architecture whereby multiple XKS instances all utilize the same store to allow for extremely high rate query access.