Semantic Event-based Service Oriented Architecture

Concept We will develop and use secure semantic event-based service oriented architecture as a common infrastructure for our testbeds and prototype integrated applications. 9/11/2018

Team Faculty Interactions with other groups Core Students Anupam Joshi Tim Finin Interactions with other groups Ravi Sandhu C Zhai Core Students Kishor Datar Audumbar Chormale 9/11/2018

Key Goals Infrastructure for Testbed Research Adding Semantics and our Policy mechanisms to WSDL, WS-Policy, WS-Security etc. Creating a system to capture events, infer context, and distribute it to the policy, information management, and social networking components. 9/11/2018

Use Open Source WS Frameworks Axis is essentially a SOAP engine - a framework for constructing SOAP processors such as clients, servers, gateways, etc. Axis also includes: A simple stand-alone server A server which plugs into servlet engines such as Tomcat Extensive support for the Web Service Description Language (WSDL) Tool that generates Java classes from WSDL. Some sample programs A tool for monitoring TCP/IP packets Open source webservices frameworks such as WSO2 based on Axis that allow webservices to be written in C/C++, Perl, Ruby, … Source: http://ws.apache.org/axis/java/user-guide.html, http://wso2.com/products/ 9/11/2018

Adding Semantics to WSDL The Web Services Description Language (WSDL) Way to describe the abstract functionalities of a service and concretely how and where to invoke it. WSDL 2.0 W3C Recommendation does not include semantics in the description Two services can have similar descriptions while meaning totally different things, or they can have very different descriptions yet similar meaning The Semantic Annotations for WSDL and XML Schema (SAWSDL) Mechanisms to add semantic annotations to WSDL components. Provides mechanisms by which concepts from the semantic models that are defined either within or outside the WSDL document can be referenced from within WSDL components as annotations. Disambiguate the description of Web services during automatic discovery and composition of the Web services. Source: http://www.w3.org/2002/ws/sawsdl/ 9/11/2018

Context Service Policies will be evaluated “in context” – the need to share is a function of the state of the world Should your medical records be proactively shared with EMTs that are responding to a natural disaster in your region ? Only if they are treating you Similar considerations for Information Management and Knowledge Discovery and Social Networks Two key issues Inferring context in face of streaming knowledge Distributing context information 9/11/2018

Inferring Context – a surgical scenario Patient Monitor Stream KB Processor (TelegraphCQ) Continuous Context Queries Knowledge Base Assert facts Assert Events RFID System Medicines Tools Staff Context Aware Agent Database Medical Encounter Record Patient History Staff Medical Supplies

CQs on Semantic Streaming Data… Reasoning process involves computationally heavy techniques such as graph traversals. In case of streaming data, the incoming data rate is much higher than time taken by the reasoner for inferencing. Hence the need for combining streaming data handling systems with reasoning techniques to build a Streaming Knowledge Base. 9/11/2018

Preliminary Steps Combining the continuous query processors with Semantic Web techniques to build a partial RDFS and OWL reasoner that can deal with streaming data. Comparing the performance of our approach with that of Jena and show that our approach achieves a soft real-time performance for fast streaming data. 9/11/2018

Pre-processing of an ontology RDFS or OWL ontology Static Data Store Property - subproperty Propertytree Class - subclass Classtree Ontology Processor Predicate - range RangeInfo DomainInfo Predicate - domain InverseInfo Property - inverse 9/11/2018

Pre-processing of an ontology rdfs:subClassOf – e.g. “Mammal” class is a subclass of “Animal” class. It’s transitive in nature. rdfs:subPropertyOf – e.g. “fatherOf” property is a sub-property of the property “parentOf”. rdfs:domain – e.g. the domain of the property “fatherOf” is “Male” class. 9/11/2018

Pre-processing of an ontology rdfs:range – e.g. the range of the property “square” is “non-negative number”. owl:inverseOf – e.g. the inverse of the property “parentOf” is “childOf” property. 9/11/2018

Stream Processing Choice of stream processing engine TelegraphCQ – Accepts a stream of tuples as input. Allows a join between static tables and dynamic streams. Can run in two modes – PostgreSQL mode - runs as a normal DBMS system. TelegraphCQ mode – can issue continuous queries to the stream. Allows Windowed queries in two ways Landmark Window – the start point of the window is fixed whereas the end point moves ahead continuously. Sliding Window – the start point as well as the end point of the window move ahead continuously. 9/11/2018

Query for Class of Concern Stream Processing Query for Class of Concern Input Triple Stream Detected Instances Input Stream Handler Event Detector Enhanced Stream Static Data Store RangeInfo DomainInfo Classtree PropertyTree InverseInfo 9/11/2018

Comparing TCQ approach to Jena approach Different ontology sizes (from 118 KB to 23.1 MB) Classes with varying numbers of subclasses (from 49 to 56,731). Classes with different depths of subclasses (from 2 to 9). Different data rates (from 1 triple per second to 100 triples per second). 9/11/2018

Comparative Graphs 9/11/2018

Comparative Graphs 9/11/2018

Comparative Graphs 9/11/2018

Publish/Subscribe mechanism for webservices Asynchronous messaging paradigm with lots of existing research and implementations Published messages classified into classes, without knowledge of what subscribers there may be Subscribers express interest in classes, and receive messages that are of interest, without knowledge of what publishers there are 9/11/2018

Problems in the Semantic Context World How do you describe classes of interest, which are elements in some ontology? A SPARQL based approach combines expressive power and efficiency SPARQL query defines trigger event of interest and additional context properties to be reported Results are RDF “graphlet” which satisfies that query and contains additional information A component can add graph result to its KB for processing 9/11/2018

Extending SPARQL RDF (including OWL and RIF) will be the standard data and knowledge interchange formalism SPARQL has good support for queries We’ll develop and implement extensions supporting other speech acts as needed, including Request Inform Negotiation actions Etc. 9/11/2018